(19)【発行国】日本国特許庁(JP)
(12)【公報種別】公開特許公報(A)
(11)【公開番号】P2022179370
(43)【公開日】2022-12-02
(54)【発明の名称】両面加工機械の運転方法および両面加工機械
(51)【国際特許分類】
B24B 37/015 20120101AFI20221125BHJP
B24B 37/08 20120101ALI20221125BHJP
B24B 57/02 20060101ALI20221125BHJP
B24B 37/005 20120101ALI20221125BHJP
H01L 21/304 20060101ALI20221125BHJP
【ＦＩ】
B24B37/015
B24B37/08
B24B57/02
B24B37/005 B
H01L21/304 621A
【審査請求】未請求
【請求項の数】10
【出願形態】ＯＬ
【外国語出願】
(21)【出願番号】P 2022074481
(22)【出願日】2022-04-28
(31)【優先権主張番号】10 2021 113 131.6
(32)【優先日】2021-05-20
(33)【優先権主張国・地域又は機関】DE
(71)【出願人】
【識別番号】517033148
【氏名又は名称】ラップマスター ヴォルターズ ゲーエムベーハー
(74)【代理人】
【識別番号】100080182
【弁理士】
【氏名又は名称】渡辺 三彦
(74)【代理人】
【識別番号】100142572
【弁理士】
【氏名又は名称】水内 龍介
(72)【発明者】
【氏名】ロバート ラブリック
【テーマコード（参考）】
3C047
3C158
5F057
【Ｆターム（参考）】
3C047FF03
3C047GG01
3C158AA07
3C158AC01
3C158AC04
3C158BA02
3C158BA08
3C158BC03
3C158CB03
3C158CB05
3C158DA18
3C158EA01
3C158EB02
5F057AA02
5F057AA34
5F057AA41
5F057BA12
5F057CA19
5F057DA02
5F057DA05
5F057DA11
5F057FA42
5F057GA07
5F057GA27
5F057GB03
5F057GB13
5F057GB31
5F057GB40
(57)【要約】
【課題】
より長時間の両面加工機械の停止時間後でも、従来技術と比較してスループットが増加し、その結果コストが減少し得る方法、および上に説明したタイプの両面加工機械を提供すること。
【解決手段】
両面加工機械、特に両面研磨機を運転する方法であって、両面加工機械は、回転駆動装置によって互いに相対的に回転可能な上部作業ディスク（１０）と下部作業ディスク（１２）とを備え、平坦なワークピースを加工するための作業ギャップ（１４）が上部作業ディスク（１０）と下部作業ディスク（１２）との間に形成されており、ワークピースを加工する加工工程の前に、加熱工程において、少なくとも作業ディスク（１０、１２）を加熱装置（３０）により運転温度に加熱することを特徴としたこと。
【選択図】図１
より長時間の両面加工機械の停止時間後でも、従来技術と比較してスループットが増加し、その結果コストが減少し得る方法、および上に説明したタイプの両面加工機械を提供すること。
【解決手段】
両面加工機械、特に両面研磨機を運転する方法であって、両面加工機械は、回転駆動装置によって互いに相対的に回転可能な上部作業ディスク（１０）と下部作業ディスク（１２）とを備え、平坦なワークピースを加工するための作業ギャップ（１４）が上部作業ディスク（１０）と下部作業ディスク（１２）との間に形成されており、ワークピースを加工する加工工程の前に、加熱工程において、少なくとも作業ディスク（１０、１２）を加熱装置（３０）により運転温度に加熱することを特徴としたこと。
【選択図】図１
【特許請求の範囲】
【請求項1】
両面加工機械、特に両面研磨機を運転する方法であって、前記両面加工機械は、回転駆動装置によって互いに相対的に回転可能な上部作業ディスク（１０）と下部作業ディスク（１２）とを備え、平坦なワークピースを加工するための作業ギャップ（１４）が前記上部作業ディスク（１０）と前記下部作業ディスク（１２）との間に形成されており、ワークピースを加工する加工工程の前に、加熱工程において、少なくとも前記作業ディスク（１０、１２）を加熱装置（３０）により運転温度に加熱することを特徴とする、方法。
【請求項2】
前記加熱工程において、加熱した加熱液体が、前記作業ギャップ（１４）に流されることを特徴とする、請求項１に記載の方法。
【請求項3】
前記加熱液体が、スラリー用の供給開口部（２３）を通って、前記作業ギャップ（１４）に流されることを特徴とする、請求項２に記載の方法。
【請求項4】
前記作業ディスク（１０、１２）が、前記加熱工程中に、前記回転駆動装置により同じ回転方向に回転することを特徴とする、請求項１から３のいずれかに記載の方法。
【請求項5】
前記作業ディスク（１０、１２）が、前記加熱工程中に、前記作業ディスク（１０、１２）の間にあるスペーサ、または前記上部および／または下部作業ディスク（１０、１２）のマウントを固定することにより、互いに所定の間隔を空けて保持され得ることを特徴とする、請求項１から４のいずれかに記載の方法。
【請求項6】
前記加熱した加熱液体を、前記上部作業ディスク（１０）および／または下部作業ディスク（１２）に設計された焼き戻しチャネル（３０）を通して、前記加熱工程中に流し得ることを特徴とする、請求項１から５のいずれかに記載の方法。
【請求項7】
少なくとも前記作業ディスク（１０、１２）が、前記加熱工程中に電気加熱装置（３０）、特に少なくとも１つの電気加熱マット（３０）により運転温度に加熱され得ることを特徴とする、請求項１から６のいずれかに記載の方法。
【請求項8】
前記上部作業ディスク（１０）および／または下部作業ディスク（１２）の温度が前記加熱工程中に測定され、前記加熱工程が前記運転温度に達した後に終了することを特徴とする、請求項１から7のいずれかに記載の方法。
【請求項9】
両面加工機械、特に両面研磨機であって、前記両面加工機械は、上部作業ディスク（１０）と下部作業ディスク（１２）とを備え、平坦なワークピースを加工するための作業ギャップ（１４）が前記上部作業ディスク（１０）と前記下部作業ディスク（１２）との間に形成されており、かつ前記両面加工機械は、前記上部作業ディスク（１０）と前記下部作業ディスク（１２）とが互いに相対的に回転可能である回転駆動装置を備え、ワークピースを加工する加工工程の前の加熱工程において、少なくとも前記作業ディスク（１０、１２）を運転温度に加熱するための加熱装置（３０）が設けられていることを特徴とする、両面加工機械。
【請求項10】
請求項１から８のいずれかに記載の方法を実施するように設計されていることを特徴とする、請求項９に記載の両面加工機械。
【発明の詳細な説明】
【技術分野】
【0001】
本発明は、両面加工機械、特に両面研磨機を運転する方法であって、両面加工機械は、回転駆動装置によって互いに相対的に回転可能な上部作業ディスクと下部作業ディスクとを備え、平坦なワークピースを加工するための作業ギャップが上部作業ディスクと下部作業ディスクとの間に形成されている方法に関する。
【0002】
また、本発明は、両面加工機械、特に両面研磨機であって、両面加工機械は、上部作業ディスクと下部作業ディスクとを備え、平坦なワークピースを加工するための作業ギャップが上部作業ディスクと下部作業ディスクとの間に形成されており、かつ両面加工機械は、上部作業ディスクと下部作業ディスクとが互いに相対的に回転可能である回転駆動装置を備える両面加工機械に関する。
【背景技術】
【0003】
両面加工機械、例えば両面研磨機では、半導体ウエハなどの平坦なワークピースが、上部作業ディスクと下部作業ディスクとの間に形成された作業ギャップで加工、例えば研磨される。加工中、作業ディスクは、回転駆動装置により互いに相対的に回転する。平坦なワークピースは、例えば、加工中に作業ギャップ中の円形経路に沿って動く、いわゆるロータディスクの凹部に配置可能であり、その間、ロータディスクの軸を中心に回転する。したがって、ワークピースは、作業ギャップを通るサイクロイド軌道に沿って誘導され、加工される。このような両面加工機械により、加工されたワークピースの非常に高い表面品質、特に非常に高い均一性が達成される。加工品質の重要なパラメータは、ＧＢＩＲ値（Ｇｌｏｂａｌ Ｂａｃｋｓｉｄｅ Ｉｄｅａｌ Ｆｏｃａｌ Ｐｌａｎｅ Ｒａｎｇｅ）であることが知られている。
【0004】
特にワークピースの物質除去加工の際には、いわゆるスラリーが、作業ギャップに供給される場合が多い。このため、上部作業ディスクおよび／または下部作業ディスクは、対応する供給開口部を有することができる。また例えば、上部作業ディスクおよび／または下部作業ディスクに、加工工程の間、作業ディスクを特定の運転温度に保持するために加工中に冷却液、例えば水を流すための、迷路状の焼き戻しチャネルを設けることも知られている。さらに例えば、加工工程の間、作業ギャップの半径方向に間隔を空けた複数の位置において、加工されたワークピースの厚さを測定し、目標とする特定の厚さに達した後に、加工工程を終了することも知られている。厚さの測定には、例えば、渦電流センサまたは光センサなどの様々なセンサが知られている。
【0005】
実際には、両面加工機械において特に長時間の停止時間の後、停止時間終了後に行われる最初の加工運転の加工結果は、最良のものではないことが示されてきた。したがって、例えば、特定のＧＢＩＲ値は通常、複数回の加工運転を行った後でないと得られず、このために必要な加工運転の回数は、両面加工機械の停止時間の長さに依存するようである。特定の品質基準に達するまで、このような加工運転の間に加工されたワークピースは、最良ではない加工結果を有し、したがって、より低い品質要件においてしか使用できず、特にいわゆるプライムウエハとしては使用できない。最良の加工品質に達するまでに必要な加工運転に試験用のワークピースを使用する場合は、不良品を回避できる。しかしながら、試験用のワークピースを使用すると、加工機械のスループットが低下し、それに対応してコストが増加することになる。
【発明の概要】
【発明が解決しようとする課題】
【0006】
上述の従来技術から進めて、本発明の目的は、より長時間の両面加工機械の停止時間後でも、従来技術と比較してスループットが増加し、その結果コストが減少し得る方法、および上に説明したタイプの両面加工機械を提供することである。
【課題を解決するための手段】
【0007】
本発明は、独立請求項１および９によって目的を達成する。有利な実施形態は、従属請求項、明細書および図面にて開示される。
【0008】
問題となっているタイプの方法において、本発明は、ワークピースを加工する加工工程の前の加熱工程において、少なくとも作業ディスクを加熱装置により運転温度に加熱するという点で、目的を達成する。問題となっているタイプの両面加工機械において、本発明は、ワークピースを加工する加工工程の前の加熱工程において、少なくとも作業ディスクを運転温度に加熱するための加熱装置を設けるという点で、目的を達成する。
【0009】
両面加工機械は、例えば両面研磨機であってもよい。ただし、例えば、両面研削機または両面ラップ盤といった、他の両面加工機械も想定される。作業ディスクは、それぞれ、作業用カバー、例えば研磨布を有することができる。平坦なワークピースは、例えば、半導体ウエハとすることができる。上部作業ディスクは、上部支持ディスクに固定可能である。それに応じて、下部作業ディスクは、下部支持ディスクに固定可能である。作業ディスクの間に形成された作業ギャップ内でのワークピースの加工中、作業ディスクは、互いに相対的に回転可能である。このために、対応する回転駆動装置が設けられる。例えば、作業ディスクは、互いに反対方向に回転するように駆動可能である。
【0010】
本発明は、特定の加工品質に達するために必要な上述の加工運転の回数は、運転の開始時にはまだかなり低温である作業ディスクの温度と関連しているという知識に基づいている。特により長時間の停止時間後は、作業ディスクと、該当する場合は支持ディスクも、運転温度未満に冷却している可能性がある。従来技術で記載された加工運転の過程においては、その後に、作業ディスクを運転温度に達するまで連続的に加熱することにより、特定の加工結果を達成してきた。しかしながら、上でも説明したように、この手順は、スループットの低下、またはそれぞれコストの増加につながる。
【0011】
したがって、本発明は、上記の加熱運転を回避するために、最初の加工工程の前に、少なくとも上部および下部作業ディスクを加熱するための、外部の加熱装置またはそれぞれ外部の加熱源を設けるという着想に基づいている。外部の加熱装置またはそれぞれ外部の加熱源はこの場合、ワークピースの加工のために提供される両面加工機械のコンポーネントに加えて設けられるものであって、それに対応して作業ギャップ内でのワークピースの加工により形成されるものではない。説明したように、そのような加工中にも熱が発生し、数回の加熱運転後に、作業ディスクが運転温度に達することにより、加工結果が必要な基準を満たすようになる。しかしながら、本発明によると、これとは別に加熱装置を設けることにより、作業ギャップ中でワークピースを加工しなくても、作業ディスクの加熱が実現される。特に、本発明による加熱工程の間、作業ギャップには加工するワークピースは配置されない。上で説明した加熱運転は、回避される。したがって、加熱工程の終了後、加工工程をすぐに続けて行うことができ、最初の加工運転で、ここで加工されるワークピースは既に、目標とするパラメータを満たす。その結果、両面加工機械のスループットが増加し、コストが減少する。上部作業ディスクおよび下部作業ディスクの運転温度は、例えば２０℃～３０℃の間の範囲であり、例えば約２５℃である。
【0012】
作業ディスクに加えて、設けられている場合は、作業ディスクを保持する支持ディスクも、当然ながら加熱装置により運転温度に加熱され得る。これにより、作業ディスクが、常に確実に運転温度を維持できる。
【0013】
説明したように、加熱工程の後、両面加工機械の作業ギャップで、ワークピースを加工する１回または複数回の加工工程が続けて行われる。加工工程は特に、例えば、研磨、ラップ加工、または研削といった、ワークピースの物質除去加工を含む。上で説明したように、このため、複数のワークピースをいわゆるロータディスクの凹部に、浮いた状態で載置できる。ロータディスクは、一方では作業ディスクを通る円形経路に沿って動き、他方では、ロータディスク自体の軸を中心に回転する。その結果、ワークピースは、作業ギャップを通るサイクロイド軌道に沿って動き、それにより最良の加工結果が達成される。ロータディスクは、例えば、作業ギャップの内側および／または外側縁部のスプロケット上を回転することができる。
【0014】
加熱工程は、両面加工機械の制御装置および／または調節装置により、制御またはそれぞれ調節され、特に開始および終了し得る。調節装置は特に、加熱源の温度および加熱工程の持続時間を、調節パラメータとして使用可能である。例えば、加熱工程中に作業ディスクが回転する場合、作業ディスクの回転スピードも、調節パラメータとして使用可能である。したがって、加熱工程は、制御装置またはそれぞれ調節装置により、制御またはそれぞれ調節可能である。
【0015】
一実施形態によると、加熱工程中に、加熱した加熱液体が作業ギャップに流される。加熱液体は、例えば、加熱源によって加熱した水とすることができる。加熱液体は、例えば、所望の運転温度よりも幾分高い温度、例えば５～１０℃高い温度を有することができる。
【0016】
特に実用的な方法では、加熱液体を、スラリー用の供給開口部を通して、作業ギャップに流すことができる。上で説明したように、上部作業ディスクおよび／または下部作業ディスクは、スラリーを作業ギャップに供給するための、そのような供給開口部を有することができる。これらの開口部を通して、作業ギャップに加熱液体を流すことができ、同時に作業ギャップ内で確実に、加熱液体が特に均一に分配されるようにする。供給開口部は、例えば、上部作業ディスクおよび／または下部作業ディスクの軸方向穴として設計される。
【0017】
加熱工程中、回転駆動装置により、作業ディスクを同じ回転方向に、具体的には、同じ方向に、さらに具体的には、同じ回転速度で回転可能である。それにより、作業ディスク、特に作業ディスクの半径方向の範囲の全体において均一な加熱、また該当する場合は、支持ディスクの均一な加熱が達成できるが、研磨パッドは影響を受けない。しかしながら、加熱工程中、作業ディスクが回転せずに、静止したままである可能性もある。
【0018】
作業ディスクは、加熱工程中、作業ディスクの間のスペーサにより、または上部作業ディスクおよび／または下部作業ディスクのマウントを固定することにより、互いに所定の間隔を空けて保持できる。これにより、作業ディスクおよび該当する場合は支持ディスクの、特に規定された効果的な加熱が達成される。このように、作業ギャップを所定の方法で設定するために、上部作業ディスクおよび／または下部作業ディスクは、対応するマウントにより高さが設定可能である。この設定は、加熱工程中に作業ディスク間に所定の距離を確保するために、前の例示的な実施形態に従って使用できる。作業ディスクを固定するために、例えば、いわゆるクランプシューズを使用できる。しかしながら、作業ディスク間に適切なスペーサを用いることにより、作業ディスク間に所定の距離を確保することも可能である。例えば、作業ギャップの半径方向外側の領域に、半径方向内側の領域よりも狭いギャップを設定することにより、スペーサをギャップ内に保持できる。
【0019】
別の実施形態によると、加熱工程中に、上部作業ディスクおよび／または下部作業ディスクに設計された焼き戻しチャネルを通して、加熱した加熱液体を流すことができる。また上で説明したように、例えば、両面加工機械の上部作業ディスクおよび／または下部作業ディスクは、焼き戻しチャネルを有し、加工中に作業ディスクの望ましくない加熱を防止するために、ワークピースの加工中、焼き戻しチャネルを通して冷却液、例えば水を流す。上部作業ディスクおよび／または下部作業ディスクに設計されたこれらの、例えば迷路状の焼き戻しチャネルは、前に記載した実施形態において、特に以下のような実用的な方法で使用可能である。加熱工程中、冷却液の代わりに、所定の方法で加熱した加熱液体を、焼き戻しチャネルを通して流すことによって、作業ディスクの加熱が効果的に実現される。当然のことながら、対応する焼き戻しチャネルを、上部作業ディスクと上部支持ディスクとの間、および／または下部作業ディスクと下部支持ディスクとの間に設計することも可能であろう。また、上部支持ディスクおよび／または下部支持ディスクに、対応する焼き戻しチャネルを設計することも想定されるであろう。したがって、このように設計された焼き戻しチャネルを通して、加熱した加熱液体を流すことも可能である。
【0020】
別の実施形態によると、加熱工程において、少なくとも作業ディスクを電気加熱装置、特に少なくとも１つの電気加熱マットにより、運転温度に加熱できる。そのような電気加熱装置、例えば、電気加熱マットは、例えば、上部作業ディスクおよび／または下部作業ディスク、上部支持ディスクおよび／または下部支持ディスクおよび／または上部作業ディスクと上部支持ディスクとの間および／または下部作業ディスクと下部支持ディスクとの間に設計可能である。そのような電気加熱装置により、作業ディスクの特に急速かつ規定された加熱が実現できる。
【0021】
別の実施形態によると、上部作業ディスクおよび／または下部作業ディスクの温度は、加熱工程中に測定可能である。そして、温度測定により運転温度に達したと判定された後、加熱工程を終了することができる。このために、例えば、加熱工程中に上部作業ディスクおよび／または下部作業ディスクの温度を測定する温度センサを、上部作業ディスクおよび／または下部作業ディスクに設計することができる。温度センサが運転温度に達したと検知すると、加熱工程を終了することができる。加熱工程は、このようにして検知された温度が運転温度に達した後、自動的に終了することができる。このため、対応する温度センサの温度測定値は、制御および／または調節装置に適用でき、したがって加熱工程の制御および／または調節は、それらの測定値に基づくことができる。
【0022】
本発明による両面加工機械は、本発明による方法を実施するために設計され得る。したがって本発明による方法は、本発明による両面加工機械により、実施可能である。
【0023】
本発明の例示的な実施形態は、図面に基づいて以下により詳細に説明される。
【図面の簡単な説明】
【0024】
【発明を実施するための形態】
【0025】
特に明記しない限り、同一の参照番号は、図中の同一の対象を示す。
【0026】
図１に示す両面加工機械は、例えば、両面研磨機であってもよく、環状の上部作業ディスク１０と、同様に環状の下部作業ディスクとを備える。作業ディスク１０、１２の間には、環状の作業ギャップ１４が形成され、その中で平坦なワークピース、例えば、半導体ウエハを加工、例えば研磨できる。説明したように、ワークピースは、浮いた状態で、いわゆるロータディスクの凹部に載置できる。ロータディスクは、作業ギャップ１４を通る円形経路に沿って動くことができ、その間、ロータディスク自体の軸を中心に回転する。このため、ロータディスクは、例えば、作業ギャップ１４の内側および／または外側縁部のスプロケット上を回転可能である。このこと自体は公知であり、したがって、より詳細には説明されない。
【0027】
上部作業ディスク１０は上部支持ディスク１６に固定され、下部作業ディスク１２は下部支持ディスク１８に固定される。作業ギャップ１４でのワークピースの加工中、上部支持ディスク１６と下部支持ディスク１８、それらと共に上部作業ディスク１０と下部作業ディスク１２は、回転軸２０を中心に回転駆動装置（より詳細には示されず）により、互いに相対的に回転する。例えば、作業ディスク１０、１２またはそれぞれ支持ディスク１６、１８は、反対方向に回転するように駆動可能である。
【0028】
図１に、上部および下部作業ディスク１０、１２のさらなる様々なコンポーネントを示す。明瞭にするために、作業ディスク１０、１２のうちの１つのみについて示す。より詳細に以下に記載される対応するコンポーネントを、作業ディスク１０、１２の両方において設計可能であることを理解されたい。
【0029】
示される例では、上部作業ディスク１０は、作業ギャップ１４にスラリーを供給するための供給ライン２２を有する。供給ライン２２はそれぞれ、作業ギャップ１４に通じる供給開口部２３を有する。さらに、図１では、距離センサ２４、例えば、渦電流センサ２４が上部作業ディスク１０に設けられており、ワークピースの加工中に、加工されるワークピースまでの距離と、作業ギャップ１４の異なる半径位置におけるワークピースの厚さとを測定する。図１では、複数の温度センサ２６も上部作業ディスク１０に設計されており、温度センサ２６は、特に加熱工程と、例えば、加工工程中においても、少なくとも上部作業ディスク１０の温度を測定する。説明したように、温度センサは、下部作業ディスク１２にも設けることができる。上部支持ディスク１６および下部支持ディスク１８についても、同様である。示される例では、温度センサ２６からの測定結果は、両面加工機械の制御および／または調節装置２８に適用される。制御および／または調節装置２８は、以下において説明される加熱工程を含む、両面加工機械の運転を制御またはそれぞれ調節する。
【0030】
また、発熱体３０を下部作業ディスク１２に概略的に示す。発熱体３０は、例えば、電気発熱体とすることができ、例えば電気発熱マット３０とすることができる。しかしながら、発熱体３０は、以下にも説明されるように、加熱工程中に、加熱した加熱液体がその中を流れる、迷路状に配置された焼き戻しチャネル３０とすることができる。発熱体３０はまた、上部作業ディスク１０に設計可能である。上部支持ディスク１６および下部支持ディスク１８についても、同様である。
【0031】
本発明による方法において、作業ギャップ１４でワークピースを加工する加工工程の前に、上部作業ディスク１０および下部作業ディスク１２の温度を、まず加熱工程において特定の運転温度にする。温度は、制御および／または調節装置２８により、制御またはそれぞれ調節可能である。例えば、加熱した加熱液体を、加熱工程で供給ライン２２および供給開口部２３を通して、作業ギャップ１４に流すことができる。加熱液体の供給中に、作業ディスク１０、１２および支持ディスク１６、１８は、作業ギャップ１４内で回転可能である。加熱工程中、例えば、上部作業ディスク１０および／または下部作業ディスク１２のマウントを固定することにより、作業ディスク１０、１２を互いに所定の間隔をおいて保持できる。温度センサ２６は、特定の運転温度に達したときに検知できる。制御および／または調節装置２８はその後、加熱工程を終了することができる。続いて、１つまたは複数の加工工程、特に例えば、研磨、ラップ加工、または研削などの物質除去加工により、ワークピースを加工できる。
【0032】
代替的にまたは追加的に、加熱工程で、加熱した加熱液体を、焼き戻しチャネル３０を通して流すことができ、それにより、作業ディスク１０、１２の温度は、特定の運転温度に上昇し得る。さらに代替的にまたは追加的に、加熱工程で、電気加熱装置３０、特に加熱マット３０を用いて、少なくとも作業ディスク１０、１２を運転温度に加熱できる。上に説明したように、運転温度の検知およびそれに対応する加熱工程の終了は、制御および／または調節装置２８により行うことができる。制御および／または調節装置２８は、供給された加熱液体の温度、機械加熱装置３０の加熱出力および加熱工程の持続時間を、制御および／または調節パラメータとして使用可能である。作業ディスク１０、１２が回転するとき、作業ディスク１０、１２の回転速度も使用可能である。
【0033】
図２は、従来技術による加熱と、本発明による加熱の結果を示す図である。それぞれの場合において、両面加工機械の加熱運転の回数に対し、規格化されたＧＢＩＲ値が示されている。曲線３２は、両面加工機械を室温で３日間稼働せず、本発明による加熱工程なしに、ワークピースを加工工程で加工するために使用した場合を指す。特定のＧＢＩＲ値（規格化された値で、可能な限り１に近くなければならない）に達するために、３回の加熱運転が必要であったことが示されている。
【0034】
曲線３４は、曲線３２に対応し、両面加工機械を一晩だけ室温で置いて、稼働させなかった場合を表す。ここでは、所望のＧＢＩＲ値に達するまでに必要な加熱運転の回数が、１回に減少している。しかしながら、対応するスループットの損失またはそれぞれに対応するコストの増加が、依然として記録される。
【0035】
曲線３６は、両面加工機械を一晩室温で置いて稼働させず、最初の加工工程（１回目の運転）の前に、本発明による加熱工程を実施した場合の結果を示す。曲線３６は、１回目の加工運転で、既に所望のＧＢＩＲ値が得られていることを示す。対応するスループットの損失またはそれぞれ対応するコストの増加が回避できた。
【符号の説明】
【0036】
１０ 上部作業ディスク
１２ 下部作業ディスク
１４ 作業ギャップ
１６ 上部支持ディスク
１８ 下部支持ディスク
２０ 回転軸
２２ 供給ライン
２３ 供給開口部
２４ 距離センサ
２６ 温度センサ
２８ 制御および／または調節装置
３０ 発熱体
３２ 曲線
３４ 曲線
３６ 曲線
１２ 下部作業ディスク
１４ 作業ギャップ
１６ 上部支持ディスク
１８ 下部支持ディスク
２０ 回転軸
２２ 供給ライン
２３ 供給開口部
２４ 距離センサ
２６ 温度センサ
２８ 制御および／または調節装置
３０ 発熱体
３２ 曲線
３４ 曲線
３６ 曲線
【図1】
【図2】
【外国語明細書】
Method for Operating a Double-Sided Processing Machine and Double-Sided Processing Machine
The invention relates to a method for operating a double-sided processing machine, in particular a double-sided polishing machine, which comprises a top working disk and a bottom working disk which can be rotated relative to each other by means of a rotary drive and between which a working gap for processing flat workpieces is formed.
The invention also relates to a double-sided processing machine, in particular a double-sided polishing machine, comprising a top working disk and a bottom working disk, between which a working gap for processing flat workpieces is formed, and comprising a rotary drive with which the top working disk and the bottom working disk can be rotated relative to each other.
In double-sided processing machines, for example double-sided polishing machines, flat workpieces such as semiconductor wafers are processed, for example polished, in a working gap formed between a top working disk and a bottom working disk. During processing, the working disks are rotated relative to each other by means of a rotary drive. The flat workpieces can be located, for example, in recesses of what are known as rotor disks which move along a circular path through the working gap during processing and in doing so rotate about their axis. The workpieces are thus guided along cycloidal paths through the working gap and processed. Very high surface qualities of the processed workpieces, in particular very high evenness, can be achieved with such double-sided processing machines. An important parameter for the processing quality is known to be the GBIR value (Global Backside Ideal Focal Plane Range).
During the in particular material-removing processing of the workpieces, what is known as slurry is often supplied to the working gap. For this purpose, the top working disk and/or the bottom working disk can have corresponding supply openings. It is also known, for example, to provide the top working disk and/or the bottom working disk with, for example, labyrinthine tempering channels through which a cooling liquid, for example water, is conducted during processing in order to keep the working disks at a specified operating temperature during a processing step. It is also known to measure the thickness of the processed workpieces, for example, at multiple radially distanced locations of the working gap, during a processing step and to terminate the processing step after a specified target thickness has been reached. For the thickness measurement, various sensors are known, for example, eddy current sensors or also optical sensors.
In practice, is has been shown that, in particular after a longer downtime of a double-sided processing machine, the processing result of the first processing runs performed after ending the downtime is not yet optimal. Thus, for example, a specified GBIR value is regularly only reached after multiple processing runs, wherein the number of the processing runs required for this seem to depend on the duration of the downtime of the double-sided processing machine. The workpieces processed during such processing runs until the specified quality criteria have been reached have a non-optimal processing result and are accordingly only usable for lower quality requirements, in particular not as what are known as prime wafers. If test workpieces are used for the processing runs required to reach the optimal processing quality, rejects can be avoided. However, this leads to a lower throughput of the processing machine and correspondingly higher costs.
Proceeding from the explained prior art, the object of the invention is to provide a method and a double-sided processing machine of the type explained above, with which the throughput can be increased compared to the prior art even after longer downtime of the double-sided processing machine and the costs can be lowered accordingly.
The invention achieves the object with the independent claims 1 and 9. Advantageous embodiments are disclosed in the dependent claims, the description and the figures.
For a method of the type in question, the invention achieves the object in that, before a processing step for processing workpieces, at least the working disks are heated to an operating temperature by means of a heating apparatus in a heating step. For a double-sided processing machine of the type in question, the invention achieves the object in that a heating apparatus is provided for heating at least the working disks to an operating temperature in a heating step before a processing step for processing workpieces.
The double-sided processing machine can be, for example, a double-sided polishing machine. However, other double-sided processing machines are also conceivable, for example, double-sided grinding machines or double-sided lapping machines. The working disks can each have a working covering, for example a polishing pad. The flat workpieces can be, for example, semiconductor wafers. The top working disk can be fastened to a top support disk. Accordingly, the bottom working disk can be fastened to a bottom support disk. During processing of workpieces in the working gap formed between the working disks, they can be rotated relative to each other. A corresponding rotary drive is provided for this. For example, the working disks can be driven to rotate in opposite directions to each other.
The invention is based on the knowledge that the processing runs described above that are required in order to reach the specified processing quality correlate with a temperature of the working disks that is still too low at the beginning. In particular after longer downtime, the working disks and if applicable the support disks can cool below the operating temperature. In the course of the processing runs described in the prior art, the working disks are then successively heated until they have reached their operating temperature and the specified processing results have thus been achieved. As also explained above, this procedure leads, however, to reduced throughput or respectively increased costs.
The invention is therefore based on the idea of providing an external heating apparatus or respectively an external heating source with which at least the top and bottom working disks are heated before a first processing step to prevent the heating runs described above. The external heating apparatus or respectively external heating source is in this case provided in addition to the components of the double-sided processing machine provided for the processing of the workpieces and is correspondingly not formed by processing workpieces in the working gap. As explained, during such processing, heat is also generated so that, after several heating runs, the working disks reach their operating temperature and the processing result thus meets the required criteria. However, according to the invention a heating apparatus is provided that is separate from this and that achieves a heating of the working disks even without processing workpieces in the working gap. In particular, during the heating step according to the invention, no workpieces to be processed are arranged in the working gap. The heating runs explained above are avoided. Accordingly, after the conclusion of the heating step, a processing step can directly follow, wherein the workpieces processed hereby already meet the target parameters in the first processing run. The throughput of the double-sided processing machine is increased accordingly and the costs are reduced. The operating temperature of the top working disk and the bottom working disk can be, for example, in a range between 20°C and 30°C, for example about 25°C.
In addition to the working disks, support disks holding the working disks, if provided, can of course also be heated to an operating temperature with the heating apparatus. This ensures that the working disks can hold their operating temperature at all times.
As explained, after the heating step one or more processing steps for processing workpieces in the working gap of the double-sided processing machine follow. The processing steps comprise in particular material-removing processing of the workpieces, for example, polishing, lapping, or grinding. As explained above, multiple workpieces can be mounted in a floating manner in recesses of what are known as rotor disks for this purpose. The rotor disks move, on one hand, along a circular path through the working gap and, on the other hand, rotate about their own axis. As a result, the workpieces move along cycloidal paths through the working gap, whereby an optimal processing result is achieved. The rotor disks can roll, for example, on sprockets on the inner and/or outer edge of the working gap.
The heating step can be controlled or respectively regulated, in particular initiated and terminated, by a control apparatus and/or a regulation apparatus of the double-sided processing machine. The regulation apparatus can use in particular the temperature of the heating source and the duration of the heating step as regulation parameters. When the working disks are rotated during the heating step, for example, the rotational speed of the working disks can also be used. Accordingly, the heating step can be controlled or respectively regulated by the control apparatus or respectively regulation apparatus.
According to one embodiment, a heated heating liquid is conducted into the working gap in the heating step. This can be, for example, water heated by means of a heating source. The heating liquid can have, for example, a somewhat higher temperature than the desired operating temperature, for example 5 to 10°C higher.
In a particularly practical manner, the heating liquid can be conducted into the working gap through supply openings for a slurry. As explained above, the top working disk and/or the bottom working disk can have such supply openings for slurry to be supplied to the working gap. The heating liquid can be conducted into the working gap through these, whereby at the same time a particularly even distribution of the heating liquid in the working gap is ensured. The supply openings are designed, for example, as axial bores in the top working disk and/or the bottom working disk.
During the heating step, the working disks can be rotated in the same direction of rotation, in particular in the same direction, further particularly with the same rotational speed, by means of a rotary drive. An even heating of the working disks, in particular of the entire radial extent of the working disks, and if applicable the support disks, can thereby be achieved, wherein the polishing pads are not influenced. However, it is also possible that the working disks are not rotated, meaning stay still, during the heating step.
The working disks can be held during the heating step by spacers between the working disks or by locking a mount of the top and/or the bottom working disk at a defined distance to each other. This achieves a particularly defined and effective heating of the working disks and if applicable the support disks. The top working disk and/or the bottom working disk can be settable in height by means of a corresponding mount in order to thus set the working gap in a defined manner. This setting can be used according to the previous exemplary embodiment in order to ensure a defined distance between the working disks during the heating step. To lock the working disks, for example, what are known as clamping shoes can be used. However, it is also possible to ensure the defined distance between the working disks by using suitable spacers between the working disks. The spacers can be held in the gap, for example, by setting a narrower gap in the radially outer region of the working gap than in the radially inner region of the working gap.
According to another embodiment, heated heating liquid can be conducted in the heating step through tempering channels designed in the top working disk and/or in the bottom working disk. As also explained above, for example, top working disks and/or bottom working disks of double-sided processing machines have tempering channels, through which a cooling liquid, for example water, is conducted during workpiece processing in order to prevent an undesired heating of the working disks during processing. These, for example labyrinthine, tempering channels designed in the top working disk and/or the bottom working disk can be used in the previous embodiment in a particularly practical manner in that, during the heating step, a heating liquid heated in a defined manner is conducted through the tempering channels instead of a cooling liquid and thus the heating of the working disks is realized effectively. Of course, it would also be possible for corresponding tempering channels to be designed between the top working disk and a top support disk and/or between a bottom working disk and a bottom support disk. It would also be conceivable for corresponding tempering channels to be designed in a top support disk and/or a bottom support disk. Accordingly, the heated heating liquid can also be conducted through tempering channels designed in this manner.
According to another embodiment, at least the working disks can be heated to an operating temperature in the heating step by means of an electrical heating apparatus, in particular by means of at least one electrical heating mat. Such an electrical heating apparatus, for example, an electrical heating mat, can be designed, for example, in the top working disk and/or the bottom working disk, in a top support disk and/or a bottom support disk and/or between a top working disk and a top support disk and/or a bottom working disk and a bottom support disk. By means of such an electrical heating apparatus, a particularly fast and defined heating of the working disks can be realized.
According to another embodiment, the temperature of the top working disk and/or the bottom working disk can be measured during the heating step, and the heating step can be terminated after the operating temperature has been reached, as determined by the temperature measurement. For this purpose, temperature sensors, for example, can be designed in the top working disk and/or the bottom working disk which measure the temperature of the top working disk and/or the bottom working disk during the heating step. If the temperature sensors detect that the operating temperature has been reached, the heating step can be terminated. The heating step can be terminated automatically after the operating temperature detected in this way has been reached. The temperature measurement values of corresponding temperature sensors can be applied for this purpose to a control and/or regulation apparatus and the control and/or regulation of the heating step can be based on them accordingly.
The double-sided processing machine according to the invention can be designed to perform the method according to the invention. Accordingly, the method according to the invention can be performed with a double-sided processing machine according to the invention.
An exemplary embodiment of the invention is explained in greater detail below based on figures. Schematically:
Figure 1 shows a double-sided processing machine according to the invention in a sectional view, and
Figure 2 shows a diagram to explain the method according to the invention.
The same reference signs refer to the same objects in the figures unless indicated otherwise.
The double-sided processing machine shown in Figure 1, in which it can be, for example, a double-sided polishing machine, has an annular top working disk 10 and a likewise annular bottom working disk 12. Between the working disks 10, 12, an annular working gap 14 is formed in which flat workpieces, for example, semiconductor wafers, can be processed, for example polished. As explained, the workpieces can be mounted in a floating manner in recesses of what are known as rotor disks. The rotor disks can be moved along a circular path through the working gap 14 and in doing so rotate about their own axis. For this purpose, the rotor disks can roll, for example, on sprockets on the inner and/or outer edge of the working gap 14. This is known per se and is therefore not explained in more detail.
The top working disk 10 is fastened to a top support disk 16, and the bottom working disk 12 is fastened to a bottom support disk 18. During processing of workpieces in the working gap 14, the top support disk 16 and the bottom support disk 18, and with them the top working disk 10 and the bottom working disk 12, are rotated relative to each other about an axis of rotation 20 by means of a rotary drive which is not shown in more detail. For example, the working disks 10, 12 or respectively the support disks 16, 18 can be driven to rotate in opposite directions.
In Figure 1, various further components of the top and bottom working disks 10, 12 are shown, wherein they are shown only for one of the working disks 10, 12 for reasons of clarity. It should be understood that the corresponding components, described in more detail in the following, can be designed in both working disks 10, 12.
In the example shown, the top working disk 10 has supply lines 22 for supplying a slurry to the working gap 14. The supply lines 22 each have supply openings 23 opening into the working gap 14. In addition, in Figure 1 distance sensors 24, for example, eddy current sensors 24, are provided in the top working disk 10 and measure the distance to the workpieces to be processed and thus their thickness at different radial locations of the working gap 14 during workpiece processing. In Figure 1, multiple temperature sensors 26 are also designed in the top working disk 10, which sensors measure the temperature at least of the top working disk 10 in particular during a heating step but also, for example, during a processing step. As explained, temperature sensors can also be provided in the bottom working disk 12. The same applies to the top support disk 16 and the bottom support disk 18. In the example shown, the measurement results from the temperature sensors 26 are applied to a control and/or regulation apparatus 28 of the double-sided processing machine. This controls or respectively regulates the operation of the double-sided processing machine, including a heating step still to be explained in the following.
A heating element 30 is also shown schematically in the bottom working disk 12. The heating element 30 can be, for example, an electrical heating element 30, for example an electrical heating mat 30. However, the heating element 30 can also be a, for example, labyrinthine arrangement of tempering channels 30 through which heated heating liquid is conducted in a heating step, as will also be explained below. The heating element 30 can in turn also be designed in the top working disk 10. The same applies to the top support disk 16 and the bottom support disk 18.
In the method according to the invention, before a processing step for processing workpieces in the working gap 14, the temperature of the top working disk 10 and the bottom working disk 12 is first brought to a specified operating temperature in a heating step. This can be controlled or respectively regulated by the control and/or regulation apparatus 28. For example, heated heating liquid can be conducted into the working gap 14 in the heating step through the supply lines 22 and the supply openings 23. The working disks 10, 12 and the support disks 16, 18 can be rotated in the working gap 14 during the supply of the heating liquid. During the heating step, the working disks 10, 12 can be held at a defined distance from each other, for example by locking a mount of the top working disk 10 and/or of the bottom working disk 12. The temperature sensors 26 can detect when the specified operating temperature has been reached. The control and/or regulation apparatus 28 can then terminate the heating step. Subsequently, workpieces can be processed in one or more processing steps, in particular material-removing processing, for example, polishing, lapping, or grinding.
Alternatively or additionally, heated heating liquid can be conducted through the tempering channels 30 in the heating step and the temperature of the working disks 10, 12 can thereby be heated to the specified operating temperature. It is further possible alternatively or additionally to heat at least the working disks 10, 12 to the operating temperature in the heating step by means of the electrical heating apparatus 30, in particular the heating mat 30. Detecting the operating temperature and the corresponding termination of the heating step can take place, as explained above, by the control and/or regulation apparatus 28. The control and/or regulation apparatus 28 can use the temperature of the supplied heating liquid, the heating output of the electrical heating apparatus 30 and the duration of the heating step as control and/or regulation parameters. When the working disks 10, 12 are rotated, the rotational speed of the working disks 10, 12 can also be used.
Figure 2 shows a diagram with results of a heating according to the prior art and according to the invention. The GBIR value is shown normalized in each case over the number of heating runs of the double-sided processing machine. The curve 32 refers to the case in which the double-sided processing machine was not operated for three nights and days at room temperature and then was used to process workpieces in processing steps without a heating step according to the invention. It is shown that three heating runs were required in order to reach a specified GBIR value, which should be as close to 1 as possible in the normalized version.
The curve 34 describes a case corresponding to the curve 32, wherein the double-sided processing machine stood idle, however, for only one night at room temperature. Here, the number of required heating runs until the desired GBIR value is reached is shortened to one run. However, a corresponding throughput loss or respectively a corresponding cost increase is still registered.
The curve 36 shows the results for a double-sided processing machine which has stood idle for one night at room temperature and in which a heating step according to the invention was performed before the first processing step (run one). The curve 36 shows that the first processing run here already has the desired GBIR value. Corresponding throughput loss or respectively corresponding cost increases could be avoided.
List of Reference Signs
10 Top working disk
12 Bottom working disk
14 Working gap
16 Top support disk
18 Bottom support disk
20 Axis of rotation
22 Supply lines
23 Supply openings
24 Distance sensors
26 Temperature sensors
28 Control and/or regulation apparatus
30 Heating element
32 Curve
34 Curve
36 Curve
The invention relates to a method for operating a double-sided processing machine, in particular a double-sided polishing machine, which comprises a top working disk and a bottom working disk which can be rotated relative to each other by means of a rotary drive and between which a working gap for processing flat workpieces is formed.
The invention also relates to a double-sided processing machine, in particular a double-sided polishing machine, comprising a top working disk and a bottom working disk, between which a working gap for processing flat workpieces is formed, and comprising a rotary drive with which the top working disk and the bottom working disk can be rotated relative to each other.
In double-sided processing machines, for example double-sided polishing machines, flat workpieces such as semiconductor wafers are processed, for example polished, in a working gap formed between a top working disk and a bottom working disk. During processing, the working disks are rotated relative to each other by means of a rotary drive. The flat workpieces can be located, for example, in recesses of what are known as rotor disks which move along a circular path through the working gap during processing and in doing so rotate about their axis. The workpieces are thus guided along cycloidal paths through the working gap and processed. Very high surface qualities of the processed workpieces, in particular very high evenness, can be achieved with such double-sided processing machines. An important parameter for the processing quality is known to be the GBIR value (Global Backside Ideal Focal Plane Range).
During the in particular material-removing processing of the workpieces, what is known as slurry is often supplied to the working gap. For this purpose, the top working disk and/or the bottom working disk can have corresponding supply openings. It is also known, for example, to provide the top working disk and/or the bottom working disk with, for example, labyrinthine tempering channels through which a cooling liquid, for example water, is conducted during processing in order to keep the working disks at a specified operating temperature during a processing step. It is also known to measure the thickness of the processed workpieces, for example, at multiple radially distanced locations of the working gap, during a processing step and to terminate the processing step after a specified target thickness has been reached. For the thickness measurement, various sensors are known, for example, eddy current sensors or also optical sensors.
In practice, is has been shown that, in particular after a longer downtime of a double-sided processing machine, the processing result of the first processing runs performed after ending the downtime is not yet optimal. Thus, for example, a specified GBIR value is regularly only reached after multiple processing runs, wherein the number of the processing runs required for this seem to depend on the duration of the downtime of the double-sided processing machine. The workpieces processed during such processing runs until the specified quality criteria have been reached have a non-optimal processing result and are accordingly only usable for lower quality requirements, in particular not as what are known as prime wafers. If test workpieces are used for the processing runs required to reach the optimal processing quality, rejects can be avoided. However, this leads to a lower throughput of the processing machine and correspondingly higher costs.
Proceeding from the explained prior art, the object of the invention is to provide a method and a double-sided processing machine of the type explained above, with which the throughput can be increased compared to the prior art even after longer downtime of the double-sided processing machine and the costs can be lowered accordingly.
The invention achieves the object with the independent claims 1 and 9. Advantageous embodiments are disclosed in the dependent claims, the description and the figures.
For a method of the type in question, the invention achieves the object in that, before a processing step for processing workpieces, at least the working disks are heated to an operating temperature by means of a heating apparatus in a heating step. For a double-sided processing machine of the type in question, the invention achieves the object in that a heating apparatus is provided for heating at least the working disks to an operating temperature in a heating step before a processing step for processing workpieces.
The double-sided processing machine can be, for example, a double-sided polishing machine. However, other double-sided processing machines are also conceivable, for example, double-sided grinding machines or double-sided lapping machines. The working disks can each have a working covering, for example a polishing pad. The flat workpieces can be, for example, semiconductor wafers. The top working disk can be fastened to a top support disk. Accordingly, the bottom working disk can be fastened to a bottom support disk. During processing of workpieces in the working gap formed between the working disks, they can be rotated relative to each other. A corresponding rotary drive is provided for this. For example, the working disks can be driven to rotate in opposite directions to each other.
The invention is based on the knowledge that the processing runs described above that are required in order to reach the specified processing quality correlate with a temperature of the working disks that is still too low at the beginning. In particular after longer downtime, the working disks and if applicable the support disks can cool below the operating temperature. In the course of the processing runs described in the prior art, the working disks are then successively heated until they have reached their operating temperature and the specified processing results have thus been achieved. As also explained above, this procedure leads, however, to reduced throughput or respectively increased costs.
The invention is therefore based on the idea of providing an external heating apparatus or respectively an external heating source with which at least the top and bottom working disks are heated before a first processing step to prevent the heating runs described above. The external heating apparatus or respectively external heating source is in this case provided in addition to the components of the double-sided processing machine provided for the processing of the workpieces and is correspondingly not formed by processing workpieces in the working gap. As explained, during such processing, heat is also generated so that, after several heating runs, the working disks reach their operating temperature and the processing result thus meets the required criteria. However, according to the invention a heating apparatus is provided that is separate from this and that achieves a heating of the working disks even without processing workpieces in the working gap. In particular, during the heating step according to the invention, no workpieces to be processed are arranged in the working gap. The heating runs explained above are avoided. Accordingly, after the conclusion of the heating step, a processing step can directly follow, wherein the workpieces processed hereby already meet the target parameters in the first processing run. The throughput of the double-sided processing machine is increased accordingly and the costs are reduced. The operating temperature of the top working disk and the bottom working disk can be, for example, in a range between 20°C and 30°C, for example about 25°C.
In addition to the working disks, support disks holding the working disks, if provided, can of course also be heated to an operating temperature with the heating apparatus. This ensures that the working disks can hold their operating temperature at all times.
As explained, after the heating step one or more processing steps for processing workpieces in the working gap of the double-sided processing machine follow. The processing steps comprise in particular material-removing processing of the workpieces, for example, polishing, lapping, or grinding. As explained above, multiple workpieces can be mounted in a floating manner in recesses of what are known as rotor disks for this purpose. The rotor disks move, on one hand, along a circular path through the working gap and, on the other hand, rotate about their own axis. As a result, the workpieces move along cycloidal paths through the working gap, whereby an optimal processing result is achieved. The rotor disks can roll, for example, on sprockets on the inner and/or outer edge of the working gap.
The heating step can be controlled or respectively regulated, in particular initiated and terminated, by a control apparatus and/or a regulation apparatus of the double-sided processing machine. The regulation apparatus can use in particular the temperature of the heating source and the duration of the heating step as regulation parameters. When the working disks are rotated during the heating step, for example, the rotational speed of the working disks can also be used. Accordingly, the heating step can be controlled or respectively regulated by the control apparatus or respectively regulation apparatus.
According to one embodiment, a heated heating liquid is conducted into the working gap in the heating step. This can be, for example, water heated by means of a heating source. The heating liquid can have, for example, a somewhat higher temperature than the desired operating temperature, for example 5 to 10°C higher.
In a particularly practical manner, the heating liquid can be conducted into the working gap through supply openings for a slurry. As explained above, the top working disk and/or the bottom working disk can have such supply openings for slurry to be supplied to the working gap. The heating liquid can be conducted into the working gap through these, whereby at the same time a particularly even distribution of the heating liquid in the working gap is ensured. The supply openings are designed, for example, as axial bores in the top working disk and/or the bottom working disk.
During the heating step, the working disks can be rotated in the same direction of rotation, in particular in the same direction, further particularly with the same rotational speed, by means of a rotary drive. An even heating of the working disks, in particular of the entire radial extent of the working disks, and if applicable the support disks, can thereby be achieved, wherein the polishing pads are not influenced. However, it is also possible that the working disks are not rotated, meaning stay still, during the heating step.
The working disks can be held during the heating step by spacers between the working disks or by locking a mount of the top and/or the bottom working disk at a defined distance to each other. This achieves a particularly defined and effective heating of the working disks and if applicable the support disks. The top working disk and/or the bottom working disk can be settable in height by means of a corresponding mount in order to thus set the working gap in a defined manner. This setting can be used according to the previous exemplary embodiment in order to ensure a defined distance between the working disks during the heating step. To lock the working disks, for example, what are known as clamping shoes can be used. However, it is also possible to ensure the defined distance between the working disks by using suitable spacers between the working disks. The spacers can be held in the gap, for example, by setting a narrower gap in the radially outer region of the working gap than in the radially inner region of the working gap.
According to another embodiment, heated heating liquid can be conducted in the heating step through tempering channels designed in the top working disk and/or in the bottom working disk. As also explained above, for example, top working disks and/or bottom working disks of double-sided processing machines have tempering channels, through which a cooling liquid, for example water, is conducted during workpiece processing in order to prevent an undesired heating of the working disks during processing. These, for example labyrinthine, tempering channels designed in the top working disk and/or the bottom working disk can be used in the previous embodiment in a particularly practical manner in that, during the heating step, a heating liquid heated in a defined manner is conducted through the tempering channels instead of a cooling liquid and thus the heating of the working disks is realized effectively. Of course, it would also be possible for corresponding tempering channels to be designed between the top working disk and a top support disk and/or between a bottom working disk and a bottom support disk. It would also be conceivable for corresponding tempering channels to be designed in a top support disk and/or a bottom support disk. Accordingly, the heated heating liquid can also be conducted through tempering channels designed in this manner.
According to another embodiment, at least the working disks can be heated to an operating temperature in the heating step by means of an electrical heating apparatus, in particular by means of at least one electrical heating mat. Such an electrical heating apparatus, for example, an electrical heating mat, can be designed, for example, in the top working disk and/or the bottom working disk, in a top support disk and/or a bottom support disk and/or between a top working disk and a top support disk and/or a bottom working disk and a bottom support disk. By means of such an electrical heating apparatus, a particularly fast and defined heating of the working disks can be realized.
According to another embodiment, the temperature of the top working disk and/or the bottom working disk can be measured during the heating step, and the heating step can be terminated after the operating temperature has been reached, as determined by the temperature measurement. For this purpose, temperature sensors, for example, can be designed in the top working disk and/or the bottom working disk which measure the temperature of the top working disk and/or the bottom working disk during the heating step. If the temperature sensors detect that the operating temperature has been reached, the heating step can be terminated. The heating step can be terminated automatically after the operating temperature detected in this way has been reached. The temperature measurement values of corresponding temperature sensors can be applied for this purpose to a control and/or regulation apparatus and the control and/or regulation of the heating step can be based on them accordingly.
The double-sided processing machine according to the invention can be designed to perform the method according to the invention. Accordingly, the method according to the invention can be performed with a double-sided processing machine according to the invention.
An exemplary embodiment of the invention is explained in greater detail below based on figures. Schematically:
Figure 1 shows a double-sided processing machine according to the invention in a sectional view, and
Figure 2 shows a diagram to explain the method according to the invention.
The same reference signs refer to the same objects in the figures unless indicated otherwise.
The double-sided processing machine shown in Figure 1, in which it can be, for example, a double-sided polishing machine, has an annular top working disk 10 and a likewise annular bottom working disk 12. Between the working disks 10, 12, an annular working gap 14 is formed in which flat workpieces, for example, semiconductor wafers, can be processed, for example polished. As explained, the workpieces can be mounted in a floating manner in recesses of what are known as rotor disks. The rotor disks can be moved along a circular path through the working gap 14 and in doing so rotate about their own axis. For this purpose, the rotor disks can roll, for example, on sprockets on the inner and/or outer edge of the working gap 14. This is known per se and is therefore not explained in more detail.
The top working disk 10 is fastened to a top support disk 16, and the bottom working disk 12 is fastened to a bottom support disk 18. During processing of workpieces in the working gap 14, the top support disk 16 and the bottom support disk 18, and with them the top working disk 10 and the bottom working disk 12, are rotated relative to each other about an axis of rotation 20 by means of a rotary drive which is not shown in more detail. For example, the working disks 10, 12 or respectively the support disks 16, 18 can be driven to rotate in opposite directions.
In Figure 1, various further components of the top and bottom working disks 10, 12 are shown, wherein they are shown only for one of the working disks 10, 12 for reasons of clarity. It should be understood that the corresponding components, described in more detail in the following, can be designed in both working disks 10, 12.
In the example shown, the top working disk 10 has supply lines 22 for supplying a slurry to the working gap 14. The supply lines 22 each have supply openings 23 opening into the working gap 14. In addition, in Figure 1 distance sensors 24, for example, eddy current sensors 24, are provided in the top working disk 10 and measure the distance to the workpieces to be processed and thus their thickness at different radial locations of the working gap 14 during workpiece processing. In Figure 1, multiple temperature sensors 26 are also designed in the top working disk 10, which sensors measure the temperature at least of the top working disk 10 in particular during a heating step but also, for example, during a processing step. As explained, temperature sensors can also be provided in the bottom working disk 12. The same applies to the top support disk 16 and the bottom support disk 18. In the example shown, the measurement results from the temperature sensors 26 are applied to a control and/or regulation apparatus 28 of the double-sided processing machine. This controls or respectively regulates the operation of the double-sided processing machine, including a heating step still to be explained in the following.
A heating element 30 is also shown schematically in the bottom working disk 12. The heating element 30 can be, for example, an electrical heating element 30, for example an electrical heating mat 30. However, the heating element 30 can also be a, for example, labyrinthine arrangement of tempering channels 30 through which heated heating liquid is conducted in a heating step, as will also be explained below. The heating element 30 can in turn also be designed in the top working disk 10. The same applies to the top support disk 16 and the bottom support disk 18.
In the method according to the invention, before a processing step for processing workpieces in the working gap 14, the temperature of the top working disk 10 and the bottom working disk 12 is first brought to a specified operating temperature in a heating step. This can be controlled or respectively regulated by the control and/or regulation apparatus 28. For example, heated heating liquid can be conducted into the working gap 14 in the heating step through the supply lines 22 and the supply openings 23. The working disks 10, 12 and the support disks 16, 18 can be rotated in the working gap 14 during the supply of the heating liquid. During the heating step, the working disks 10, 12 can be held at a defined distance from each other, for example by locking a mount of the top working disk 10 and/or of the bottom working disk 12. The temperature sensors 26 can detect when the specified operating temperature has been reached. The control and/or regulation apparatus 28 can then terminate the heating step. Subsequently, workpieces can be processed in one or more processing steps, in particular material-removing processing, for example, polishing, lapping, or grinding.
Alternatively or additionally, heated heating liquid can be conducted through the tempering channels 30 in the heating step and the temperature of the working disks 10, 12 can thereby be heated to the specified operating temperature. It is further possible alternatively or additionally to heat at least the working disks 10, 12 to the operating temperature in the heating step by means of the electrical heating apparatus 30, in particular the heating mat 30. Detecting the operating temperature and the corresponding termination of the heating step can take place, as explained above, by the control and/or regulation apparatus 28. The control and/or regulation apparatus 28 can use the temperature of the supplied heating liquid, the heating output of the electrical heating apparatus 30 and the duration of the heating step as control and/or regulation parameters. When the working disks 10, 12 are rotated, the rotational speed of the working disks 10, 12 can also be used.
Figure 2 shows a diagram with results of a heating according to the prior art and according to the invention. The GBIR value is shown normalized in each case over the number of heating runs of the double-sided processing machine. The curve 32 refers to the case in which the double-sided processing machine was not operated for three nights and days at room temperature and then was used to process workpieces in processing steps without a heating step according to the invention. It is shown that three heating runs were required in order to reach a specified GBIR value, which should be as close to 1 as possible in the normalized version.
The curve 34 describes a case corresponding to the curve 32, wherein the double-sided processing machine stood idle, however, for only one night at room temperature. Here, the number of required heating runs until the desired GBIR value is reached is shortened to one run. However, a corresponding throughput loss or respectively a corresponding cost increase is still registered.
The curve 36 shows the results for a double-sided processing machine which has stood idle for one night at room temperature and in which a heating step according to the invention was performed before the first processing step (run one). The curve 36 shows that the first processing run here already has the desired GBIR value. Corresponding throughput loss or respectively corresponding cost increases could be avoided.
List of Reference Signs
10 Top working disk
12 Bottom working disk
14 Working gap
16 Top support disk
18 Bottom support disk
20 Axis of rotation
22 Supply lines
23 Supply openings
24 Distance sensors
26 Temperature sensors
28 Control and/or regulation apparatus
30 Heating element
32 Curve
34 Curve
36 Curve
Claims
1. A method for operating a double-sided processing machine, in particular a double-sided polishing machine, which comprises a top working disk (10) and a bottom working disk (12) which can be rotated relative to each other by means of a rotary drive and between which a working gap (14) for processing flat workpieces is formed, characterized in that, before a processing step for processing workpieces, at least the working disks (10, 12) are heated to an operating temperature by means of a heating apparatus (30) in a heating step.
2. The method according to claim 1, characterized in that a heated heating liquid is conducted into the working gap (14) in the heating step.
3. The method according to claim 2, characterized in that the heating liquid is conducted into the working gap (14) through supply openings (23) for a slurry.
4. The method according to any of the preceding claims, characterized in that the working disks (10, 12) are rotated in the same direction of rotation by means of the rotary drive during the heating step.
5. The method according to any of the preceding claims, characterized in that the working disks (10, 12) can be held during the heating step by spacers between the working disks (10, 12) or by locking a mount of the top and/or the bottom working disk (10, 12) at a defined distance from each other.
6. The method according to any of the preceding claims, characterized in that heated heating liquid can be conducted in the heating step through tempering channels (30) designed in the top working disk (10) and/or in the bottom working disk (12).
7. The method according to any of the preceding claims, characterized in that at least the working disks (10, 12) can be heated to an operating temperature in the heating step by means of an electrical heating apparatus (30), in particular at least one electrical heating mat (30).
8. The method according to any of the preceding claims, characterized in that the temperature of the top working disk (10) and/or the bottom working disk (12) is measured during the heating step, and that the heating step is terminated after the operating temperature has been reached.
9. A double-sided processing machine, in particular a double-sided polishing machine, comprising a top working disk (10) and a bottom working disk (12), between which a working gap (14) for processing flat workpieces is formed, and comprising a rotary drive with which the top working disk (10) and the bottom working disk (12) can be rotated relative to each other, characterized in that a heating apparatus (30) is provided for heating at least the working disks (10, 12) to an operating temperature in a heating step before a processing step for processing workpieces.
10. The double-sided processing machine according to claim 9, characterized in that it is designed to perform the method according to any of claims 1 to 8.
1. A method for operating a double-sided processing machine, in particular a double-sided polishing machine, which comprises a top working disk (10) and a bottom working disk (12) which can be rotated relative to each other by means of a rotary drive and between which a working gap (14) for processing flat workpieces is formed, characterized in that, before a processing step for processing workpieces, at least the working disks (10, 12) are heated to an operating temperature by means of a heating apparatus (30) in a heating step.
2. The method according to claim 1, characterized in that a heated heating liquid is conducted into the working gap (14) in the heating step.
3. The method according to claim 2, characterized in that the heating liquid is conducted into the working gap (14) through supply openings (23) for a slurry.
4. The method according to any of the preceding claims, characterized in that the working disks (10, 12) are rotated in the same direction of rotation by means of the rotary drive during the heating step.
5. The method according to any of the preceding claims, characterized in that the working disks (10, 12) can be held during the heating step by spacers between the working disks (10, 12) or by locking a mount of the top and/or the bottom working disk (10, 12) at a defined distance from each other.
6. The method according to any of the preceding claims, characterized in that heated heating liquid can be conducted in the heating step through tempering channels (30) designed in the top working disk (10) and/or in the bottom working disk (12).
7. The method according to any of the preceding claims, characterized in that at least the working disks (10, 12) can be heated to an operating temperature in the heating step by means of an electrical heating apparatus (30), in particular at least one electrical heating mat (30).
8. The method according to any of the preceding claims, characterized in that the temperature of the top working disk (10) and/or the bottom working disk (12) is measured during the heating step, and that the heating step is terminated after the operating temperature has been reached.
9. A double-sided processing machine, in particular a double-sided polishing machine, comprising a top working disk (10) and a bottom working disk (12), between which a working gap (14) for processing flat workpieces is formed, and comprising a rotary drive with which the top working disk (10) and the bottom working disk (12) can be rotated relative to each other, characterized in that a heating apparatus (30) is provided for heating at least the working disks (10, 12) to an operating temperature in a heating step before a processing step for processing workpieces.
10. The double-sided processing machine according to claim 9, characterized in that it is designed to perform the method according to any of claims 1 to 8.
Abstract
The invention relates to a method for operating a double-sided processing machine, in particular a double-sided polishing machine, which comprises a top working disk and a bottom working disk which can be rotated relative to each other by means of a rotary drive and between which a working gap for processing flat workpieces is formed, wherein, before a processing step for processing workpieces, at least the working disks are heated to an operating temperature by means of a heating apparatus in a heating step. The invention also relates to a corresponding double-sided processing machine.
The invention relates to a method for operating a double-sided processing machine, in particular a double-sided polishing machine, which comprises a top working disk and a bottom working disk which can be rotated relative to each other by means of a rotary drive and between which a working gap for processing flat workpieces is formed, wherein, before a processing step for processing workpieces, at least the working disks are heated to an operating temperature by means of a heating apparatus in a heating step. The invention also relates to a corresponding double-sided processing machine.