JP4818505B2

JP4818505B2 - Wafer polishing head

Info

Publication number: JP4818505B2
Application number: JP2000319376A
Authority: JP
Inventors: 由夫中村; 晴道小山
Original assignee: FUJIKOSHI MACHINE INDUSTRY CO.,LTD.
Current assignee: FUJIKOSHI MACHINE INDUSTRY CO.,LTD.
Priority date: 2000-10-19
Filing date: 2000-10-19
Publication date: 2011-11-16
Anticipated expiration: 2020-10-19
Also published as: JP2002134447A

Description

【０００１】
【発明の属する技術分野】
本発明はウェーハ研磨ヘッドに関し、更に詳細には定盤に貼付された研磨布の研磨面に近接可能に設けられた本体部と、本体部内に出入可能に設けられ、ウェーハの被研磨面が研磨面に対向するようにウェーハを保持するウェーハ保持盤とを具備するウェーハ研磨ヘッドに関する。
【０００２】
【従来の技術】
ウェーハ研磨装置には、回転可能に設けられた定盤に貼付された研磨布の研磨面に近接可能に設けられた本体部と、この本体部内に出入可能に設けられ、ウェーハの被研磨面が研磨面に対向するようにウェーハを保持するウェーハ保持盤とを具備するウェーハ研磨ヘッドが設けられている。
かかるウェーハ研磨ヘッドが設けられたウェーハ研磨装置では、研磨剤を供給した研磨布の研磨面に、ウェーハ保持盤に保持されたウェーハの被研磨面を所定の荷重で押し付けつつ、定盤を回転させてウェーハの被研磨面を鏡面研磨する。
しかし、研磨作業中にウェーハの角部の過研磨等に因って研磨布の研磨面に毛羽立ちや波打ち等の荒れが生ずることがある。この様な荒れが生ずると、研磨精度が低下し易くなる。また、ウェーハの角部が過研磨されると、研磨後のウェーハに厚み斑が発生し易い。
【０００３】
かかる研磨布の研磨面に生じる毛羽立ちや波打ち及び研磨後のウェーハの厚み斑等を解消すべく、特開平４−３４３６５８号公報には、図４に示すウェーハ研磨ヘッド１００が提案されている。
このウェーハ研磨ヘッド１００には、シリンダ装置等の昇降駆動手段（図示せず）及びモータ等の回転駆動手段（図示せず）によって上下動可能に設けられた回転主軸１０２の下端部に固着された本体部１０４と、本体部１０４の定盤（図示せず）側に開口された凹部内に、リング状の弾性膜体１０８によって吊持されたウェーハ保持盤１０６とが出入可能に設けられ、且つ本体部１０４の定盤側には、ウェーハ保持盤１０６を囲むように、リング状の修正板１１０が固着されている。
かかる本体部１０４内には、本体部１０４の凹部内壁面、ウェーハ保持盤１０６の表面及び弾性膜体１０８によって囲まれた空間部１１２が形成され、この空間部１１２内には、加圧手段１１４からの圧縮空気が給排気される。
尚、ウェーハ保持盤１０６の定盤側には、真空ポンプ等の減圧手段１１８に連結された通路１２０によってウェーハ１１６が減圧吸着されている。
【０００４】
【発明が解決しようとする課題】
図４に示すウェーハ研磨ヘッド１００は、シリンダ装置等の昇降駆動手段によってウェーハ研磨ヘッド１００を所定位置まで降下し、本体部１０４に設けられたウェーハ保持盤１０６に減圧吸着されているウェーハ１１６の被研磨面を、定盤に貼着された研磨布の研磨面に近接させる。
次いで、加圧手段１１４からの圧縮空気を空間部１１２に供給し、ウェーハ保持盤１０６を弾性膜体１０８の吊持力に抗して押出すことにより、ウェーハ１１６の被研磨面を研磨布の研磨面に所定の押圧力（荷重）で押圧できる。
その後、モータ等の回転駆動手段を駆動してウェーハ研磨ヘッド１００を回転しつつ、所定の押圧力（荷重）を加えてウェーハ１１６の被研磨面を研磨する。
【０００５】
この様に、シリンダ装置等の昇降駆動手段及び加圧手段１１４からの圧縮空気によってウェーハ１１６の被研磨面を、定盤に貼着された研磨布の研磨面に所定の押圧力で押圧した際、本体部１０４の定盤側にウェーハ保持盤１０６を囲むように固着したリング状の修正板１１０も、図５に示す様に、研磨布１２２を押圧する。
したがって、研磨の際に、ウェーハ保持盤１０６に吸着されたウェーハ１１６によって押圧される研磨布１２２の押圧面と、その周縁部も修正板１１０によって押圧されている押圧面とは、図５に示す様に、実質的に同一面にできる。
このため、ウェーハ１１６の角部の過研磨等に起因した、研磨布１２２の研磨面に毛羽立ちや波打ち等の発生及び研磨後のウェーハ１１６に生ずる厚み斑を防止できる。
しかし、修正板１１０による研磨布１２２の押圧量は、シリンダ装置等の昇降駆動手段によるウェーハ研磨ヘッド１００の降下位置によって決定され、修正板１１０の研磨布１２２の押圧量を単独で調整できない。
このため、研磨の際に、修正板１１０とウェーハ１１６との研磨布１２２の押圧量を実質的に同一となるように調整できない場合、図６に示す如く、修正板１１０によって押圧された押圧面と、ウェーハ１１６の被研磨面によって押圧された研磨布１２２の押圧面とが相違し、両押圧面との段差面にウェーハ１１６の角部が接触して研磨される。
この様に、ウェーハ１１６の角部が段差面によって研磨されると、研磨布１２２の研磨面に毛羽立ちや波打ち等の荒れが発生し易くなり、研磨後のウェーハにも厚み斑が発生し易くなる。
そこで、本発明の課題は、研磨の際に、ウェーハ保持盤に保持されたウェーハの被研磨面による研磨布の押圧量と、ウェーハの被研磨面による研磨布の押圧面の周縁面を押圧する修正部材の押圧量とを、単独で容易に調整し得るウェーハ研磨ヘッドを提供することにある。
【０００６】
【課題を解決するための手段】
本発明者等は、前記課題を解決すべく、先ず、修正部材とウェーハ保持盤との研磨布に対する押圧量を、互いに独立して調整可能となるように、修正部材とウェーハ保持盤とを別個の弾性膜体によってウェーハ研磨ヘッドの本体部に吊持したところ、修正部材とウェーハ保持盤との研磨布に対する押圧量を単独で調整できたものの、修正部材に定盤の研磨面に対して平行方向への揺れが発生するため、修正部材による研磨布の押圧量の正確な調整は困難であった。
このため、本発明者等は更に検討を重ねた結果、修正部材とウェーハ保持盤との研磨布に対する押圧量を互いに独立して調整可能となるように、別個の弾性膜体によってウェーハ研磨ヘッドの本体部に吊持すると共に、修正部材の研磨面と平行方向への揺れ防止部材を設けることによって、ウェーハ保持盤の研磨布に対する押圧量に対応して修正部材による研磨布の押圧量を容易に且つ正確に調整できることを見出し、本発明に到達した。
【０００７】
すなわち、本発明は、定盤に貼付された研磨布の研磨面に近接可能に設けられた本体部と、前記本体部内に出入可能に設けられ、ウェーハの被研磨面が前記研磨面に対向するように前記ウェーハを保持するウェーハ保持盤とを具備し、前記本体部が前記研磨布の研磨面に近接した際に、前記ウェーハの被研磨面が前記研磨布の研磨面に所定の荷重で押し付けられて研磨されるように、前記ウェーハ保持盤が前記本体部から押出されるウェーハ研磨ヘッドにおいて、該本体部には、前記ウェーハの被研磨面を前記研磨布の研磨面に所定の荷重で押し付けて研磨する際に、前記ウェーハの被研磨面によって押圧される前記研磨布の押圧面の周縁面を、前記押圧面と同一面となるように、前記研磨布の研磨面を押圧して修正する修正部材が、前記ウェーハ保持盤を囲むように設けられ、且つ前記ウェーハ保持盤及び修正部材の各々は、前記定盤の研磨布を押圧する押圧量を互いに独立して調整可能となるように、前記本体部に装着されていると共に、前記修正部材の前記研磨面に対して平行方向への揺れ止めを図る揺れ止め部材が設けられ、該揺れ止め部材は、研磨ヘッドの本体部にウェーハ保持盤を吊持する装着部材から延出されて形成され、第１弾性膜体によって前記修正部材上部が前記本体部に吊持され、前記第１弾性膜体とは別体の第２弾性膜体が、前記修正部材中途部と前記本体部とに固着されて、前記揺れ止め部材として該修正部材の揺れ止めを図り、前記第１弾性膜体の上面と前記本体部の内壁面とによって囲まれた空間部に、加圧手段から圧縮空気を供給して、前記修正部材の前記研磨布方向への押出量を調整することを特徴とするウェーハ研磨ヘッドにある。
【０００８】
かかる本発明において、ウェーハ保持盤と修正部材との各々を、本体部に弾性膜体から成る装着部材によって吊持することにより、ウェーハ保持盤と修正部材との研磨布の押圧量の調整に圧縮空気を用いることができる。
また、修正部材の揺れ止め部材を、弾性膜体によって形成することにより、修正部材の揺れ止めを容易に図ることができる。
更に、修正部材の揺れ止め部材を、研磨ヘッドの本体部にウェーハ保持盤を吊持する装着部材から延出して形成することによって、揺れ止め部材と装着部材とを一体化でき、部品点数の増加を抑制できる。
【０００９】
ウェーハ研磨ヘッドのウェーハ保持盤に保持されているウェーハの被研磨面を、定盤に貼着されている研磨布の研磨面に所定の荷重を加えて研磨する際には、ウェーハ研磨ヘッドの本体部を、ウェーハの被研磨面が定盤の研磨面に近接する所定位置まで降下した後、本体部からウェーハ保持盤を定盤の研磨面方向に押出し、ウェーハの被研磨面を研磨布の研磨面に押し付ける。
したがって、高荷重で研磨する場合は、研磨ヘッドの本体部からのウェーハ保持盤の押出量が、低荷重で研磨する場合に比較して大となる。このため、従来の如く、修正部材が研磨ヘッドの本体部に固着されていると、研磨する際に、ウェーハに加えられる荷重によって、ウェーハ保持盤の本体部からの押出量が異なるため、ウェーハの被研磨面による研磨布の押圧量と、修正部材による研磨布の押圧量とが相違する。
この点、本発明によれば、ウェーハ保持盤と修正部材との定盤に貼付された研磨布に対する押圧量を互いに独立して調整できる。このため、修正部材による定盤の研磨布に対する押圧量を、ウェーハの被研磨面による定盤の研磨面に対する押圧量に対応して適正量となるように単独で調整できる。
しかも、修正部材は、定盤の研磨布を押圧する際に、研磨布の研磨面に対して平行方向への揺れ止めを図ることができ、修正部材の定盤の研磨布に対する押圧量を正確に調整できる。
【００１０】
【発明の実施の形態】
本発明に係るウェーハ研磨ヘッドの一例を図１に示す。図１は、ウェーハ研磨ヘッド１０の概略を説明する概略断面図である。
ウェーハ研磨ヘッド１０には、シリンダ装置等の昇降駆動手段（図示せず）及びモータ等の回転駆動手段（図示せず）によって、定盤２２に貼着された研磨布２４に対して上下動可能に設けられた回転主軸１２の下端部に、本体部１４が固着されている。この本体部１４には、定盤２２側に開口された凹部１６と、凹部１６を囲むように形成された環状凹部２０とが形成されており、凹部１６内には、ウェーハ保持盤１８が設けられている。更に、環状凹部２０には、定盤２２の研磨布２４の研磨面に平行に延出された延出部２６ａと、延出部２６ａに直交し且つ研磨布２４に対して垂直な垂直部２６ｂとから成る、縦断面形状がＬ字状の修正部材２６が設けられている。このため、修正部材２６は、ウェーハ保持盤１８を囲むように設けられている。
尚、ウェーハ保持盤１８の研磨布２４側には、真空ポンプ等の減圧手段４２に連結された通路４４によってウェーハ４６が減圧吸着されている。
【００１１】
凹部１６内に設けられたウェーハ保持盤１８は、ウェーハ保持盤１８に一端部が固着されていると共に、凹部１６と環状凹部２０とを画する境界部３０に中途部が固定されたリング状のゴム等から成る弾性膜体２８によって、本体部１４に吊持されている。更に、弾性膜体２８の他端部は、修正部材２６の垂直部２６ｂの中途部に固着され、修正部材２６の研磨布２４と平行方向への揺れ止めを図っている。
かかる凹部１６の内壁面、ウェーハ保持盤１８の表面及び弾性膜体２８によって、空間部３２が形成されており、空間部３２内には、加圧手段３４からの圧縮空気が給排気される。加圧手段３４からの圧縮空気が空間部３２に供給された際には、ウェーハ保持盤１８は弾性膜体２８の吊持力に抗して研磨布２４の方向に凹部１６から押出され、加圧手段３４からの圧縮空気の供給が停止され、空間部３２から圧縮空気が排気された際には、ウェーハ保持盤１８は弾性膜体２８の吊持力によって、凹部３２内に引き戻される。
したがって、空間部３２内の圧縮空気の圧力を調整することによって、ウェーハ保持盤１８の凹部３２からの押出量を調整できる。
【００１２】
この様に、ウェーハ保持盤１８を本体部１４に吊持する弾性膜体２８は、ウェーハ保持盤１８の周縁に沿ってリング状に形成されており、図２（ａ）に示す様に、その一端部がウェーハ保持盤１８の周縁端に固着されていると共に、中途部が本体部１４の一部である境界部３０の先端面に固着されている。更に、弾性膜体２８の他端部は、修正部材２６の垂直部２６ｂの中途に固着されている。
かかる弾性膜体２８のうち、ウェーハ保持盤１８の周縁端と境界部３０の先端面との間は、加圧手段３４から圧縮空気が供給される空間部３２を形成するため、ウェーハ保持盤１８の周縁端及び境界部３０の先端面と弾性膜体２８とが全周に亘って密着していることを要する。このため、ウェーハ保持盤１８の周縁端及び境界部３０の先端面に、弾性膜体２８の中途部及び一端部をリング状の固着板４８，５０を挟み込み螺子等によって固着することにより、ウェーハ保持盤１８の周縁端及び境界部３０の先端面に弾性膜体１８の中途部及び一端部を全周に亘って密着させることができる。
【００１３】
かかる弾性膜体２８の境界部３０の先端面から延出された弾性膜体２８の他端部は、修正部材２６の垂直部２６ｂの中途部に固着されている。弾性膜体２８の境界部３０の先端面から修正部材２６の間は、修正部材２６の研磨布２４の研磨に対して平行方向への揺れ止めを図る揺れ止め部材として作用する。このため、修正部材２６の垂直部２６ｂの中途部に弾性膜体２８の他端部が固着されていればよく、密着していることは要しない。したがって、螺子のみによって弾性膜体２８の他端部を垂直部２６ｂの中途部に固着できる。
【００１４】
また、縦断面形状がＬ字状の修正部材２６は、その垂直部２６ｂの端面が環状凹部２０の内壁面間に掛け渡されたリング状のゴム等から成る弾性膜体３６に固着され、延出部２６ａが研磨布２４の研磨面に平行となるように本体部１４内に吊持されている。
更に、環状凹部２０の内壁面及び弾性膜体３６によって囲まれた空間部３８が形成され、この空間部３８には、加圧手段４０からの圧縮空気が給排気される。加圧手段４０からの圧縮空気が空間部３８に供給された際には、修正部材２６は弾性膜体３６の吊持力に抗して研磨布２４の方向に本体部１４から押出され、加圧手段４０からの圧縮空気の供給が停止され、空間部３８から圧縮空気が排気された際には、修正部材２６は弾性膜体３６の吊持力によって、本体部１４内に引き戻される。
したがって、空間部３８内の圧縮空気の圧力を調整することによって、修正部材２６の延出部２６ａの研磨布２４方向への押出量を調整できる。
【００１５】
この様に、修正部材２６を本体部１４に吊持する弾性膜体３６は、リング状に形成され、環状凹部２０の内壁面間に掛け渡されている。かかる弾性膜体３６の一端部は、リング状の固着板５２によって環状凹部２０を形成する内壁面の一方側に、リング状の固着板５２によって本体部１４に固着され、他端部は内壁面の一方側に挟み込まれて固着されている。
かかる弾性膜体３６には、修正部材２６の垂直部２６ａの端面が、バックアップリング５４を介して固着されている。この固着にも、螺子等によって垂直部２６ｂに固着されたリング状の固着板５６が用いられている。
また、バックアップリング５４は、幅狭の垂直部２６ｂの端面よりも幅広に形成されており、弾性膜体３６の動作を幅狭の垂直部２６ｂの端面に伝達できる。
【００１６】
図１及び図２に示すウェーハ研磨ヘッド１０によって、ウェーハ保持盤１８に保持されたウェーハ４６の被研磨面を研磨する際には、シリンダ装置等の昇降駆動手段（図示せず）によってウェーハ研磨ヘッド１０を降下し、ウェーハ保持盤１８に保持されたウェーハ４６の被研磨面を定盤２２に貼着された研磨布２４の研磨面に近接させる。
次いで、加圧手段３４を駆動して圧縮空気を空間部３２に供給し、ウェーハ４６の被研磨面が研磨布２４の研磨面を所定の荷重で押圧するように、ウェーハ保持盤１８を本体部１４の凹部１６から押出す。
更に、加圧手段４０を駆動して空間部３８に圧縮空気を供給し、修正部材２６の延出部２６ａを本体部１４から押出し、図２（ａ）に示す様に、ウェーハ４６の被研磨面による研磨布２４の押圧面と、延出部２６ａによる研磨布２４の押圧面とが実質的に同一面とする。この際に、修正部材２６は、弾性膜体２８によって研磨布２４に対して平行方向への揺れを防止できるため、修正部材２６を形成する延出部２６ａの本体部１４からの押出量を正確に且つ容易に調整できる。
その後、定盤２２及びウェーハ研磨ヘッド１０を異なる速度で回転することによって、ウェーハ保持盤１８に保持されているウェーハ４６の被研磨面を研磨できる。
かかる研磨の際には、図２（ａ）に示す様に、ウェーハ４６の被研磨面による研磨布２４の押圧面と、延出部２６ａによる研磨布２４の押圧面とが実質的に同一面とすることができ、ウェーハ４６の角部等が研磨布２４による過研磨を防止できると共に、研磨布２４の研磨面に毛羽立ちや波打ち等の発生を防止できる。このため、ウェーハ４６の研磨精度を向上できる。
尚、以上、説明してきた図１及び図２では、弾性膜体２８の一部を修正部材２６の揺れ止め部材として用いているが、弾性膜体２８と別体の弾性膜体を揺れ止め部材として用いてもよく、非弾性体から成る揺れ止め部材を用いてもよい。
【００１７】
図１及び図２に示す修正部材２６の延出部２６ａは、図３に示す様に、ウェーハ４６の全周を囲むように形成されている。かかる延出部２６ａは、図２（ａ）に示す様に、研磨布２４の研磨面に接触するため、スラリー状の研磨液（以下、スラリーと称することがある）がウェーハ４６の研磨面に供給され難くなる場合がある。
この場合、図３に示す様に、修正部材２６の延出部２６ａの研磨布２４と接触する面に、スラリーが通る溝５８，５８・・を形成することが好ましい。かかる溝５８、５８・・の各々の形状を、修正部材２６の回転方向（矢印Ｒ）に沿った曲線状とすることによって、修正部材２６の矢印Ｒ方向への回転によって、スラリーは矢印Ｓ方向にウェーハ４６の研磨面に供給される。
この様に、修正部材２６の延出部２６ａに溝５８，５８・・を形成することは、ウェーハ４６の直径に対して定盤２２の直径が充分に大きい場合に好適である。
一方、ウェーハ４６の直径に対し、定盤２２の直径が同等乃至若干大きい程度の場合（定盤２２が小さい場合）は、ウェーハ１２に被研磨面の全面にスラリーを効果的に供給することは難しい。このため、ウェーハ４６の被研磨面が接触する研磨布２４にスラリーが直接供給される様に、定盤２２及び研磨布２４に穿設したスラリー供給用孔からスラリーを噴出してもよい。
【００１８】
【発明の効果】
本発明に係るウェーハ研磨ヘッドによれば、研磨の際に、ウェーハの角部等が研磨布による過研磨を防止できると共に、研磨布の研磨面に毛羽立ちや波打ち等の発生を防止できる。その結果、ウェーハの研磨精度を向上できる。
【図面の簡単な説明】
【図１】本発明に係るウェーハ研磨ヘッドの概要を説明する縦断面図である。
【図２】図１に示す弾性膜体２８、３６の固着状態を説明する部分断面図である。
【図３】修正部材２６の延出部２６ａの研磨布２４と接触する面の形状を説明する正面図である。
【図４】従来のウェーハ研磨ヘッドの概要を説明する縦断面図である。
【図５】図４に示すウェーハ研磨ヘッドを用いた研磨状況を説明するための部分断面図である。
【図６】図４に示すウェーハ研磨ヘッドを用いた他の研磨状況を説明するための部分断面図である。
【符号の説明】
１０ウェーハ研磨ヘッド
１２回転主軸
１４本体部
１６凹部
１８ウェーハ保持盤
２０環状凹部
２２定盤
２４研磨布
２６修正部材
２８，３６弾性膜体
３０境界部
３２，３８空間部
３４，４０加圧手段
４２減圧手段
４６ウェーハ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wafer polishing head, and more specifically, a main body provided so as to be close to a polishing surface of a polishing cloth affixed to a surface plate, and provided so as to be able to enter and exit from the main body. The present invention relates to a wafer polishing head comprising a wafer holding disk for holding a wafer so as to face the surface.
[0002]
[Prior art]
The wafer polishing apparatus is provided with a main body portion provided close to a polishing surface of a polishing cloth affixed to a surface plate provided in a rotatable manner, and a main body portion detachably provided in the main body portion. A wafer polishing head including a wafer holding disk for holding the wafer so as to face the polishing surface is provided.
In a wafer polishing apparatus provided with such a wafer polishing head, the surface plate is rotated while pressing the surface to be polished of the wafer held by the wafer holding plate against the polishing surface of the polishing cloth supplied with the abrasive with a predetermined load. Then, the polished surface of the wafer is mirror-polished.
However, roughness such as fuzz and undulation may occur on the polishing surface of the polishing cloth due to overpolishing of the corners of the wafer during the polishing operation. When such roughening occurs, the polishing accuracy tends to decrease. Further, if the corner portion of the wafer is overpolished, unevenness of thickness is likely to occur on the polished wafer.
[0003]
In order to eliminate the fuzz and waviness generated on the polishing surface of the polishing cloth and the uneven thickness of the polished wafer, Japanese Patent Laid-Open No. 4-343658 proposes a wafer polishing head 100 shown in FIG.
The wafer polishing head 100 is fixed to a lower end portion of a rotary spindle 102 that can be moved up and down by a lift drive means (not shown) such as a cylinder device and a rotary drive means (not shown) such as a motor. A main body 104 and a wafer holder 106 suspended by a ring-shaped elastic film body 108 are provided in a recessed manner opened on the surface plate (not shown) side of the main body 104 so as to be able to enter and exit, and A ring-shaped correction plate 110 is fixed to the surface plate side of the main body 104 so as to surround the wafer holding plate 106.
In the main body 104, a space 112 surrounded by the inner wall surface of the concave portion of the main body 104, the surface of the wafer holding plate 106 and the elastic film body 108 is formed. Compressed air from is supplied and exhausted.
Incidentally, the wafer 116 is adsorbed to the surface of the wafer holding plate 106 under reduced pressure by a passage 120 connected to a pressure reducing means 118 such as a vacuum pump.
[0004]
[Problems to be solved by the invention]
The wafer polishing head 100 shown in FIG. 4 lowers the wafer polishing head 100 to a predetermined position by a lift drive means such as a cylinder device, and covers the wafer 116 to be sucked by the wafer holding plate 106 provided in the main body 104 under reduced pressure. The polishing surface is brought close to the polishing surface of the polishing cloth adhered to the surface plate.
Next, compressed air from the pressurizing means 114 is supplied to the space portion 112, and the wafer holding plate 106 is pushed out against the suspending force of the elastic film body 108, whereby the surface to be polished of the wafer 116 is made of a polishing cloth. The polishing surface can be pressed with a predetermined pressing force (load).
Thereafter, the surface to be polished of the wafer 116 is polished by applying a predetermined pressing force (load) while rotating the wafer polishing head 100 by driving a rotation driving means such as a motor.
[0005]
In this way, when the surface to be polished of the wafer 116 is pressed against the polishing surface of the polishing cloth adhered to the surface plate with a predetermined pressing force by the compressed air from the raising / lowering driving means and the pressurizing means 114 such as a cylinder device. The ring-shaped correction plate 110 fixed so as to surround the wafer holding plate 106 on the surface plate side of the main body 104 also presses the polishing cloth 122 as shown in FIG.
Accordingly, FIG. 5 shows the pressing surface of the polishing pad 122 pressed by the wafer 116 adsorbed on the wafer holder 106 during polishing and the pressing surface whose peripheral portion is also pressed by the correction plate 110. Similarly, it can be made substantially the same surface.
For this reason, it is possible to prevent the occurrence of fluffing and undulation on the polishing surface of the polishing pad 122 due to overpolishing of the corners of the wafer 116, and unevenness in the thickness of the wafer 116 after polishing.
However, the pressing amount of the polishing pad 122 by the correction plate 110 is determined by the lowered position of the wafer polishing head 100 by the lift driving means such as a cylinder device, and the pressing amount of the polishing pad 122 of the correction plate 110 cannot be adjusted independently.
Therefore, when the amount of pressing of the polishing pad 122 between the correction plate 110 and the wafer 116 cannot be adjusted to be substantially the same during polishing, the pressing surface pressed by the correction plate 110 as shown in FIG. And the pressing surface of the polishing pad 122 pressed by the surface to be polished of the wafer 116 is different from each other, and the corner portion of the wafer 116 comes into contact with the step surface between the pressing surfaces and is polished.
As described above, when the corner portion of the wafer 116 is polished by the stepped surface, the polishing surface of the polishing cloth 122 is likely to be rough, such as fluffing and undulation, and thickness unevenness is also likely to occur in the polished wafer. .
Accordingly, the object of the present invention is to press the amount of pressing of the polishing cloth by the polished surface of the wafer held by the wafer holder and the peripheral surface of the pressing surface of the polishing cloth by the polished surface of the wafer during polishing. An object of the present invention is to provide a wafer polishing head capable of easily adjusting the pressing amount of the correction member independently.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors first separate the correction member and the wafer holding plate from each other so that the pressing amount of the correction member and the wafer holding plate against the polishing cloth can be adjusted independently of each other. When the elastic film body is suspended from the main body of the wafer polishing head, the pressing amount of the correction member and the wafer holding plate against the polishing cloth can be adjusted independently, but the correction member is parallel to the polishing surface of the surface plate. Since the vibration in the direction occurs, it is difficult to accurately adjust the pressing amount of the polishing pad by the correction member.
For this reason, as a result of further studies, the inventors have made it possible to adjust the amount of pressing of the correction member and the wafer holding plate against the polishing cloth independently of each other by using a separate elastic film body. By suspending on the main body and providing an anti-swaying member in the direction parallel to the polishing surface of the correction member, the pressing amount of the polishing cloth by the correction member can be easily adjusted in accordance with the pressing amount of the wafer holder against the polishing cloth. And the inventors have found that it can be adjusted accurately, and have reached the present invention.
[0007]
That is, the present invention provides a main body provided to be close to the polishing surface of the polishing cloth affixed to the surface plate, and provided so as to be able to enter and exit from the main body, and the surface to be polished of the wafer faces the polishing surface. And a wafer holding disk for holding the wafer, and when the main body is close to the polishing surface of the polishing cloth, the surface to be polished of the wafer is pressed against the polishing surface of the polishing cloth with a predetermined load. In the wafer polishing head in which the wafer holding disk is pushed out from the main body so as to be polished, the main body is pressed against the polishing surface of the wafer against the polishing surface of the polishing cloth with a predetermined load. When polishing, the peripheral surface of the pressing surface of the polishing cloth pressed by the surface to be polished of the wafer is corrected by pressing the polishing surface of the polishing cloth so that it is flush with the pressing surface. The correction member is The wafer holding plate and the correction member are provided on the main body so that the pressing amount for pressing the polishing cloth of the surface plate can be adjusted independently of each other. An anti- sway member that is mounted and prevents the correction member from shaking in a direction parallel to the polishing surface is provided, and the anti- sway member suspends the wafer holding disk on the main body of the polishing head. The correction member upper part is suspended from the main body by the first elastic film body, and the second elastic film body separate from the first elastic film body is formed from the mounting member. Affixed to the midway part and the main body part, aiming to prevent the correction member as the anti-sway member, and in the space part surrounded by the upper surface of the first elastic film body and the inner wall surface of the main body part, Supply the compressed air from the pressurizing means, the correction In the wafer polishing head and adjusting the extrusion amount of the the polishing cloth direction of wood.
[0008]
In the present invention, each of the wafer holding plate and the correction member is suspended on the main body by a mounting member made of an elastic film body, thereby compressing the pressing amount of the polishing cloth between the wafer holding plate and the correction member. Air can be used.
In addition, by forming the anti-sway member of the correction member with an elastic film body, it is possible to easily prevent the correction member from shaking.
Furthermore, the anti-sway member of the correction member extends from the mounting member that suspends the wafer holder on the main body of the polishing head, so that the anti-sway member and the mounting member can be integrated, increasing the number of parts. Can be suppressed.
[0009]
When polishing the polished surface of the wafer held by the wafer holding disk of the wafer polishing head by applying a predetermined load to the polishing surface of the polishing cloth adhered to the surface plate, the main body of the wafer polishing head After the wafer surface is lowered to a predetermined position where the polished surface of the wafer is close to the polishing surface of the surface plate, the wafer holding plate is pushed out from the main body toward the polishing surface of the surface plate, and the polished surface of the wafer is polished by the polishing cloth. Press against the surface.
Therefore, in the case of polishing with a high load, the amount of extrusion of the wafer holder from the main body of the polishing head becomes larger than that in the case of polishing with a low load. For this reason, if the correction member is fixed to the main body of the polishing head as in the prior art, the amount of extrusion from the main body of the wafer holder varies depending on the load applied to the wafer during polishing. The pressing amount of the polishing pad by the surface to be polished is different from the pressing amount of the polishing pad by the correction member.
In this regard, according to the present invention, it is possible to independently adjust the amount of pressing against the polishing cloth affixed to the surface plate of the wafer holding plate and the correction member. For this reason, the pressing amount of the surface plate on the polishing pad by the correction member can be adjusted independently so as to be an appropriate amount corresponding to the pressing amount of the polishing surface of the wafer on the polishing surface of the surface plate.
In addition, when the correction member presses the polishing cloth of the surface plate, the correction member can prevent shaking in a direction parallel to the polishing surface of the polishing cloth. Can be adjusted.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
An example of a wafer polishing head according to the present invention is shown in FIG. FIG. 1 is a schematic sectional view for explaining the outline of the wafer polishing head 10.
The wafer polishing head 10 can be moved up and down with respect to the polishing cloth 24 affixed to the surface plate 22 by a lift drive means (not shown) such as a cylinder device and a rotation drive means (not shown) such as a motor. A main body portion 14 is fixed to the lower end portion of the rotary main shaft 12 provided on the main body 14. The main body 14 is formed with a recess 16 opened to the surface plate 22 side and an annular recess 20 formed so as to surround the recess 16, and a wafer holding plate 18 is provided in the recess 16. It has been. Further, the annular recess 20 includes an extended portion 26 a extending parallel to the polishing surface of the polishing cloth 24 of the surface plate 22, and a vertical portion 26 b perpendicular to the extending portion 26 a and perpendicular to the polishing cloth 24. And a correction member 26 having an L-shaped longitudinal section is provided. Therefore, the correction member 26 is provided so as to surround the wafer holding plate 18.
Incidentally, the wafer 46 is adsorbed on the polishing pad 24 side of the wafer holding plate 18 by a passage 44 connected to a decompression means 42 such as a vacuum pump.
[0011]
The wafer holder 18 provided in the recess 16 has a ring-like shape in which one end is fixed to the wafer holder 18 and a midway part is fixed to a boundary 30 that defines the recess 16 and the annular recess 20. The main body 14 is suspended by an elastic film body 28 made of rubber or the like. Further, the other end portion of the elastic film body 28 is fixed to the middle portion of the vertical portion 26 b of the correction member 26 to prevent the correction member 26 from shaking in the direction parallel to the polishing pad 24.
A space 32 is formed by the inner wall surface of the recess 16, the surface of the wafer holder 18 and the elastic film body 28, and compressed air from the pressurizing means 34 is supplied and exhausted into the space 32. When the compressed air from the pressurizing means 34 is supplied to the space 32, the wafer holder 18 is pushed out of the recess 16 in the direction of the polishing cloth 24 against the suspension force of the elastic film body 28, and applied. When the supply of compressed air from the pressure means 34 is stopped and the compressed air is exhausted from the space 32, the wafer holding plate 18 is pulled back into the recess 32 by the suspension force of the elastic film body 28.
Therefore, by adjusting the pressure of the compressed air in the space 32, the amount of extrusion from the recess 32 of the wafer holder 18 can be adjusted.
[0012]
As described above, the elastic film body 28 for suspending the wafer holding plate 18 on the main body 14 is formed in a ring shape along the peripheral edge of the wafer holding plate 18, and as shown in FIG. One end portion is fixed to the peripheral edge of the wafer holding plate 18, and the midway portion is fixed to the front end surface of the boundary portion 30 that is a part of the main body portion 14. Further, the other end portion of the elastic film body 28 is fixed in the middle of the vertical portion 26 b of the correction member 26.
In the elastic film body 28, a space portion 32 to which compressed air is supplied from the pressurizing means 34 is formed between the peripheral edge of the wafer holding plate 18 and the front end surface of the boundary portion 30. It is necessary that the peripheral edge and the distal end surface of the boundary portion 30 and the elastic film body 28 are in close contact with each other over the entire circumference. For this reason, the middle part and one end part of the elastic film body 28 are sandwiched between the peripheral edge of the wafer holding plate 18 and the front end surface of the boundary part 30 with the ring-like fixing plates 48 and 50 sandwiched between them and fixed by screws or the like. The middle part and one end part of the elastic film body 18 can be brought into close contact with the peripheral edge of the board 18 and the front end surface of the boundary part 30 over the entire circumference.
[0013]
The other end portion of the elastic film body 28 extending from the front end surface of the boundary portion 30 of the elastic film body 28 is fixed to the middle portion of the vertical portion 26 b of the correction member 26. A space between the front end surface of the boundary portion 30 of the elastic film body 28 and the correction member 26 functions as a vibration preventing member for preventing the correction member 26 from shaking in a direction parallel to the polishing of the polishing pad 24. For this reason, the other end part of the elastic film body 28 should just be fixed to the middle part of the perpendicular part 26b of the correction member 26, and it is not necessary to adhere | attach. Therefore, the other end portion of the elastic film body 28 can be fixed to the middle portion of the vertical portion 26b only by the screw.
[0014]
The correcting member 26 having an L-shaped longitudinal cross section is fixed to an elastic film body 36 made of a ring-shaped rubber or the like in which the end surface of the vertical portion 26b is stretched between the inner wall surfaces of the annular recess 20 and extends. The protruding portion 26 a is suspended in the main body portion 14 so as to be parallel to the polishing surface of the polishing pad 24.
Further, a space 38 surrounded by the inner wall surface of the annular recess 20 and the elastic film body 36 is formed, and compressed air from the pressurizing means 40 is supplied to and discharged from the space 38. When the compressed air from the pressurizing means 40 is supplied to the space portion 38, the correction member 26 is pushed out from the main body portion 14 in the direction of the polishing cloth 24 against the suspension force of the elastic film body 36 and applied. When the supply of compressed air from the pressure means 40 is stopped and the compressed air is exhausted from the space 38, the correction member 26 is pulled back into the main body 14 by the suspension force of the elastic film body 36.
Therefore, by adjusting the pressure of the compressed air in the space 38, the amount of extension of the extending portion 26a of the correction member 26 in the direction of the polishing pad 24 can be adjusted.
[0015]
In this way, the elastic film body 36 that suspends the correction member 26 on the main body 14 is formed in a ring shape, and is stretched between the inner wall surfaces of the annular recess 20. One end portion of the elastic film body 36 is fixed to one side of the inner wall surface forming the annular recess 20 by the ring-shaped fixing plate 52, and the other end portion is fixed to the main body portion 14 by the ring-shaped fixing plate 52. It is sandwiched and fixed to one side of the.
The end face of the vertical portion 26 a of the correction member 26 is fixed to the elastic film body 36 via a backup ring 54. For this fixing, a ring-shaped fixing plate 56 fixed to the vertical portion 26b with a screw or the like is used.
The backup ring 54 is formed wider than the end surface of the narrow vertical portion 26b, and the operation of the elastic film body 36 can be transmitted to the end surface of the narrow vertical portion 26b.
[0016]
When polishing the surface to be polished of the wafer 46 held on the wafer holder 18 by the wafer polishing head 10 shown in FIGS. 1 and 2, the wafer polishing head is moved by a lifting drive means (not shown) such as a cylinder device. 10 is lowered, and the surface to be polished of the wafer 46 held on the wafer holding plate 18 is brought close to the polishing surface of the polishing pad 24 attached to the surface plate 22.
Next, the pressurizing means 34 is driven to supply compressed air to the space 32, and the wafer holding plate 18 is moved to the main body so that the surface to be polished of the wafer 46 presses the polishing surface of the polishing pad 24 with a predetermined load. It extrudes from the 14 recessed parts 16. FIG.
Further, the pressurizing means 40 is driven to supply compressed air to the space portion 38, the extending portion 26a of the correction member 26 is pushed out from the main body portion 14, and the wafer 46 is polished as shown in FIG. The pressing surface of the polishing pad 24 by the surface and the pressing surface of the polishing pad 24 by the extending portion 26a are substantially the same surface. At this time, since the correcting member 26 can prevent the elastic film body 28 from shaking in the direction parallel to the polishing pad 24, the amount of extension of the extending portion 26a forming the correcting member 26 from the main body portion 14 can be accurately determined. And can be adjusted easily.
Thereafter, the surface to be polished of the wafer 46 held on the wafer holding plate 18 can be polished by rotating the surface plate 22 and the wafer polishing head 10 at different speeds.
At the time of such polishing, as shown in FIG. 2A, the pressing surface of the polishing pad 24 by the surface to be polished of the wafer 46 and the pressing surface of the polishing pad 24 by the extending portion 26a are substantially the same surface. In addition, the corners of the wafer 46 can be prevented from being overpolished by the polishing cloth 24, and the occurrence of fluffing and waving on the polishing surface of the polishing cloth 24 can be prevented. For this reason, the polishing accuracy of the wafer 46 can be improved.
1 and 2 described above, a part of the elastic film body 28 is used as an anti-sway member for the correction member 26, but the elastic film body separate from the elastic film body 28 is used as an anti-sway member. Or an anti-sway member made of an inelastic material may be used.
[0017]
The extension part 26a of the correction member 26 shown in FIGS. 1 and 2 is formed so as to surround the entire circumference of the wafer 46, as shown in FIG. As shown in FIG. 2A, the extending portion 26 a comes into contact with the polishing surface of the polishing pad 24, so that a slurry-like polishing liquid (hereinafter sometimes referred to as slurry) is applied to the polishing surface of the wafer 46. It may be difficult to be supplied.
In this case, as shown in FIG. 3, it is preferable to form grooves 58, 58... Through which the slurry passes on the surface of the extending portion 26 a of the correction member 26 that contacts the polishing pad 24. The shape of each of the grooves 58, 58,... Is curved along the direction of rotation of the correction member 26 (arrow R), so that the slurry is rotated in the direction of arrow S by the rotation of the correction member 26 in the direction of arrow R. To the polishing surface of the wafer 46.
In this way, forming the grooves 58, 58... In the extending portion 26 a of the correction member 26 is suitable when the diameter of the surface plate 22 is sufficiently larger than the diameter of the wafer 46.
On the other hand, when the diameter of the surface plate 22 is equal to or slightly larger than the diameter of the wafer 46 (when the surface plate 22 is small), the slurry can be effectively supplied to the entire surface of the surface to be polished to the wafer 12. difficult. Therefore, the slurry may be ejected from the slurry supply holes formed in the surface plate 22 and the polishing cloth 24 so that the slurry is directly supplied to the polishing cloth 24 with which the surface to be polished of the wafer 46 contacts.
[0018]
【The invention's effect】
According to the wafer polishing head of the present invention, during polishing, the corners of the wafer can be prevented from being overpolished by the polishing cloth, and the occurrence of fluffing and undulation on the polishing surface of the polishing cloth can be prevented. As a result, the polishing accuracy of the wafer can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view for explaining an outline of a wafer polishing head according to the present invention.
FIG. 2 is a partial cross-sectional view for explaining a fixed state of elastic film bodies 28 and 36 shown in FIG.
FIG. 3 is a front view for explaining the shape of the surface of the extension part 26a of the correction member 26 that comes into contact with the polishing pad 24;
FIG. 4 is a longitudinal sectional view for explaining an outline of a conventional wafer polishing head.
FIG. 5 is a partial cross-sectional view for explaining a polishing situation using the wafer polishing head shown in FIG. 4;
6 is a partial sectional view for explaining another polishing situation using the wafer polishing head shown in FIG. 4; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Wafer grinding | polishing head 12 Main axis | shaft 14 Main-body part 16 Recessed part 18 Wafer holding board 20 Annular recessed part 22 Surface plate 24 Polishing cloth 26 Correction member 28, 36 Elastic film body 30 Boundary part 32, 38 Space part 34, 40 Pressurizing means 42 Decompression Means 46 Wafer

Claims

A main body provided so as to be close to the polishing surface of the polishing cloth affixed to the surface plate, and provided in the main body so as to be able to enter and exit, and holds the wafer so that the polished surface of the wafer faces the polishing surface. And a wafer holding disk that, when the main body is close to the polishing surface of the polishing cloth, the polishing surface of the wafer is pressed against the polishing surface of the polishing cloth with a predetermined load and polished. In the wafer polishing head in which the wafer holding plate is extruded from the main body,
The main body portion has a peripheral surface of the pressing surface of the polishing cloth that is pressed by the polishing surface of the wafer when the polishing surface of the wafer is pressed against the polishing surface of the polishing cloth with a predetermined load. A correction member that presses and corrects the polishing surface of the polishing cloth so as to be the same surface as the pressing surface is provided so as to surround the wafer holding plate,
And each of the wafer holding plate and the correction member is mounted on the main body so that the pressing amount for pressing the polishing cloth of the surface plate can be adjusted independently of each other,
An anti- sway member for preventing the correction member from shaking in a direction parallel to the polishing surface is provided, and the anti- sway member extends from a mounting member that suspends a wafer holding disk on the main body of the polishing head. Formed,
The upper part of the correction member is suspended from the main body by the first elastic film body,
A second elastic film body separate from the first elastic film body is fixed to the middle part of the correction member and the main body part, and the correction member is prevented from shaking as the anti-swing member;
Compressed air is supplied from the pressurizing means to the space surrounded by the upper surface of the first elastic film body and the inner wall surface of the main body to adjust the amount of extrusion of the correction member in the polishing cloth direction. A wafer polishing head characterized by that.

The wafer polishing head according to claim 1, wherein the wafer holding disk is suspended from the main body portion by a mounting member made of an elastic film body.