JP3615592B2

JP3615592B2 - Polishing equipment

Info

Publication number: JP3615592B2
Application number: JP17460395A
Authority: JP
Inventors: 安雄稲田; 孝昭酒井
Original assignee: FUJIKOSHI MACHINE INDUSTRY CO.,LTD.
Current assignee: FUJIKOSHI MACHINE INDUSTRY CO.,LTD.
Priority date: 1995-07-11
Filing date: 1995-07-11
Publication date: 2005-02-02
Anticipated expiration: 2015-07-11
Also published as: JPH0929618A

Description

【０００１】
【産業上の利用分野】
本発明は、研磨装置に関し、さらに詳細にはワークを保持する保持部と、表面に研磨面が形成された定盤と、前記保持部と定盤とを相対的に運動させる運動機構を備える研磨装置に関する。この研磨装置としては、例えば半導体チップ用のウェーハ表面を鏡面研磨するために用いるウェーハの研磨装置がある。
【０００２】
【従来の技術】
近年、半導体装置の高集積化が進むに伴い、その基板であるシリコンウェーハの平坦度や表面品質の向上が厳しく要求されている。また、そのウェーハ表面にデバイスを形成した際の堆積形成された層間絶縁膜や金属配線の研磨においても、一層高精度に平坦化する要求が高まっている。従って、ウェーハの研磨装置については、ウェーハ表面を一層高精度に鏡面研磨できるもの、または、表面を基準とする高精度な研磨が要求されている。
【０００３】
従来、ウェーハの研磨装置には、ウェーハ表面の全面が、そのウェーハ表面に接触する定盤の研磨面へ、均等な圧力で押圧できるように、ウェーハを保持する保持部がエアバック機能を備えるものがある。
その研磨装置の保持部の一例を、図３に基づいて以下に説明する。
図３に示すように、回転する定盤５６上に軟質弾性部材からなる研磨布５８を接着して研磨面６０が形成され、その上方には回転および上下動可能な保持部４１が設けられている。その保持部４１は、下方に向けて開放する凹状のヘッド部材１１と、外側部１３ａがヘッド部材１１の内底面に固定されると共に内側部１３ｂが保持部材（以下、保持プレート１７と称することがある。）に固定されて保持プレート１７を上下方向及び水平方向への移動を微小範囲内で許容可能に吊持する板状の弾性部材１３と、ヘッド部材１１の内部を保持プレート１７および板状の弾性部材１３によって画成して設けられる密閉空間である圧力室１９と、圧力室１９に所定圧力の流体を供給する流体の供給手段（図示せず）とを具備する。また、２７はリング状の弾性部材であり、合成ゴム等により成形されたＯ−リング状の部材からなる。このリング状の弾性部材２７は、保持プレート１７の外周面と前記外壁側部１１ａの内周面との間に配され、保持プレート１７のヘッド部材１１との相対的移動（例えば相対的回転）を吸収および規制するように作用する。
【０００４】
この研磨装置によれば、保持プレート１７に水張り等で保持されたウェーハ表面は、板状の弾性部材１３のエアバック作用によって、研磨面６０の傾斜に素早く追随できると共に、そのようにウェーハ表面が研磨面６０の傾斜に追随した状態においても、ウェーハ表面全面を研磨面６０に均等な圧力で押圧できる。このため、ウェーハ４２の高い平行度及び平坦度を維持しつつウェーハの表面を好適に鏡面研磨できる。なお、保持プレート１７の表面には、ウェーハ４２を確実に水張りできるように、一般的に吸着性に富む表面を有するシート状のバッキング材が貼設されている。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記のウェーハの研磨装置では、保持プレートを介してウェーハを間接的に押圧しているから、保持プレートの平坦度の精度、保持プレートに加圧力が作用した際の変形による寸法変化、およびバッキング材の厚さの精度等による影響を受け易く、ウェーハの全面を、非常に高い精度で研磨することは難しいという課題があった。
また、ウェーハの外周部が多く研磨される傾向にあり、いわゆる外周のダレが発生し易く、ウェーハの全面について非常に高い精度の平坦度が要求される場合には対応できないという課題があった。
【０００６】
本発明の目的は、ワーク全面を研磨面へ均等に押圧することによってワーク全面を均一に研磨し、ワーク外周のダレを防止すると共に、ワーク表面の平坦度を向上できる研磨装置を提供することにある。
【０００７】
【課題を解決するための手段】
上記の目的を達成するため、本発明は次の構成を備える。
すなわち、本発明は、ワークを保持する保持部と、表面に研磨面が形成された定盤と、前記保持部と定盤とを相対的に運動させる運動機構とを備える研磨装置において、前記保持部が、下方に向けて開放する凹部を備えるヘッド部材と、該ヘッド部材の凹部内側に配された保持部材と、外側部が前記ヘッド部材の壁部に固定されると共に、内側部が前記保持部材に固定され、該保持部材を上下方向及び水平方向への移動を微小範囲内で許容可能に吊持する弾性部材と、前記ヘッド部材の内部を前記保持部材および前記弾性部材によって画成して設けられる第１圧力室と、弾性のある薄膜からなり、前記保持部材の外面側に外周部で固定され、外側面でワークに当接して該ワークを前記定盤の研磨面へ押圧可能に設けられた弾性薄膜と、前記保持部材の外側面および前記弾性薄膜の内側面によって画成される第２圧力室とを備え、前記第１圧力室へは第１流体供給手段によって所定圧力の流体が供給され、前記第２圧力室へは第２流体供給手段によって所定圧力の流体が供給されることを特徴とする研磨装置。
【０００８】
また、前記第１流体供給手段には第１圧力室へ供給される流体の圧力を調整する第１圧力調整装置が備えられ、前記第２流体供給手段には第２圧力室へ供給される流体の圧力を調整する第２圧力調整装置が備えられていることで、ワークの種々の研磨条件に好適に適応させることができ、研磨装置の汎用性が向上する。
【０００９】
【作用】
本発明によれば、第１圧力室へ第１流体供給手段によって所定圧力の流体を供給することで、保持部材全体を研磨面の傾斜に追随させることができると共に、第２圧力室へ第２流体供給手段によって所定圧力の流体を供給することで、弾性薄膜を介して、より直接的に流体圧による等圧力を作用させ、ワークを研磨面へ押圧することができる。
すなわち、第１圧力室の圧力で保持部材全体を研磨面へ均等な圧力で押圧し、保持部材と定盤表面の平行度を高い精度で確保し、加えて、第２圧力室の圧力でワークをより直接的に押圧できるため、さらに高い精度にワークを研磨面へ均等に押圧できる。従って、ワーク全面を均一に研磨することができる。
【００１０】
【実施例】
以下、本発明を、ウェーハの研磨装置に適用した場合の好適な実施例について、添付図面に基づいて詳細に説明する。
図１はウェーハの研磨装置の保持部４１ａの構成を示す正面断面図であり、図２は図１のウェーハの研磨装置を使用した場合の要部を拡大した状態を示す正面断面図である。
１０はヘッド部材であり、ワークであるウェーハを保持する保持部の外形部を構成する。このヘッド部材１０は、下方へ開放する凹状に形成されている。本実施例では、ヘッド部材１０は平板壁部１０ｂと筒状側壁部１０ｃによって構成されており、平板壁部１０ｂと筒状側壁部１０ｃの継ぎ合わせは、Ｏ−リング１１によって気密されている。
１２は保持プレートであり、ウェーハを保持するための保持部材の一態様である。この保持プレート１２は、ヘッド部材１０の凹部内側に配されている。
【００１１】
１４は弾性部材の一態様である板状の弾性部材であり、例えば硬質のゴム板材（本実施例では布入りニトリルゴム）によってドーナツ状に形成されている。外側部１４ａがヘッド部材１０の内底面に固定されると共に内側部１４ｂが保持プレート１２に固定されている。これにより、板状の弾性部材１４は、保持プレート１２を上下方向及び水平方向への移動を微小範囲内で許容可能に吊持している。板状の弾性部材１４の外側部１４ａは、ヘッド部材１０の内底面１０ａへ、ボルト（図示せず）の締め付けでリング部材１６によって挟さまれて固定される。また、板状の弾性部材１４の内側部１４ｂは、ボルト（図示せず）の締め付けで押さえリング１８に挟まれて保持プレート１２に固定されている。
【００１２】
２０は第１圧力室であり、ヘッド部材１０の内部を保持プレート１２および板状の弾性部材１４によって画成して設けられている。この第１圧力室２０内へは、所定圧力の流体が第１流体供給手段（図示せず）によって供給される。２２は第１配管であり、第１流体供給手段の圧力源と第１圧力室２０を連通している。前記第１流体供給手段には、第１圧力室２０へ供給される流体の圧力を調整する第１圧力調整装置（図示せず）が備えられている。
２６はリング状の弾性部材であり、例えばゴム等により成形されたＯ−リング状の部材からなる。このリング状の弾性部材２６は、保持プレート１２の外周面と筒状側壁部１０ｃの内周面の双方に当接するように配設され、保持プレート１２の水平方向の移動を微小範囲内で許容している。これにより、ウェーハが研磨される際に発生する水平方向（特に径方向）への作用力を吸収することができる。
【００１３】
３０は弾性薄膜であり、弾性のある薄膜からなり、保持プレート１２の外面側に、外周部３０ｂが、ボルト（図示せず）の締め付けで固定リング３１に挟まれることで固定されている。この弾性薄膜３０は、その外側面でワークに当接して、エアバック作用でワークを定盤の研磨面へ均等に押圧できるように設けられている。この弾性薄膜３０としては、シート状の弾性材と、吸着性に富む表面を有するシート状のバッキング材とを貼り合わせたものを用いることができる。また、表面がバッキング材の性質を有し、全体としては弾性材の作用をすることのできるよう、弾性材とバッキング材を合成した状態のものでもよい。このようにバッキング材を用いることで、弾性薄膜３０の表面にウェーハ２４が水等の液体の表面張力によって確実に貼着されている。
３２は第２圧力室であり、保持プレート１２の外側面１２ａおよび弾性薄膜３０の内側面３０ａによって画成される。この第２圧力室３２内へは、所定圧力の流体が第２流体供給手段（図示せず）によって供給される。なお、この第２流体供給手段の圧力源は、第２配管３３、管継手３４、および連通路３６を介して第２圧力室３２に連通している。
前記第２流体供給手段には第２圧力室３２へ供給される流体の圧力を調整する第２圧力調整装置（図示せず）が備えられている。
【００１４】
２８は凹部であり、ヘッド部材１０に設けられている。この凹部２８はヘッド部材１０の周方向に所定の間隔をおいて複数が設けられている。
３８はピン状部材であり、保持プレート１２に、凹部２８に対応して所定の間隔をおいて複数が立設されている。ピン状部材３８は、前記凹部２８へ挿入されて係合する凸部の一態様である。
このピン状部材３８は、フランジ状の先端部３８ａを備えており、凹部２８を形成する内底面２８ａと内径部２８ｂとの間で移動が規制される。これにより、保持プレート１２の上下方向の移動が規制されている。
また、ピン状部材の先端部３８ａは、凹部２８に対して所定の微小範囲内で相対的に移動可能に遊嵌された状態で係合する係合部として作用する。従って、ヘッド部材１０と保持プレート１２との微小範囲の相対的移動を許容し、板状の弾性部材１４に作用する複合力を緩和することができる。これにより、板状の弾性部材が損傷することを防止でき、結果的にエアーバック機能の低下を防止できる。
なお、本実施例では、保持プレート１２（保持部材）側にピン状部材３８（係合部）が設けられ、ヘッド部材１０側に凹部２８（被係合部）が設けられているが、逆に、保持部材に被係合部を設け、ヘッド部材１０側に係合部が設けられてもよい。
【００１５】
４０はテンプレートであり、弾性薄膜３０の外面側（下面）に装着され、ウェーハ２４を囲うことが可能に形成されており、ウェーハの横滑りを防止する。このテンプレート４０の厚さは、ウェーハ２４の厚さと同等に設定されている（本実施例では、ウェーハ２４の厚さよりも若干薄く設けられている）。なお、研磨剤（砥粒を含む液状の研磨剤）がテンプレート４０内に好適に供給されるように、テンプレート４０の表面に複数の溝を設けてもよい。
このようにテンプレート４０を設けることで、保持プレート１２が、そのテンプレート４０によって定盤５６の研磨面６０に受けられる（図２参照）ため、ウェーハ２４の外周のダレが発生することを防止できる。
【００１６】
なお、上記のウェーハの保持部、およびウェーハの保持部に設けられてウェーハ２４を研磨面６０に所定の押圧力で押圧する押圧手段の他に、ウェーハの研磨装置の基本的な構成としては、表面に研磨面６０が形成された定盤５６（図２および図３参照）、ウェーハ表面を研磨面６０に当接させるべくウェーハの保持部と定盤５６とを接離動させる接離動手段、ウェーハ２４が研磨面６０に当接・押圧された状態でウェーハ２４と定盤５６とを回転および／または往復動によって相対的に運動させる駆動手段、スラリー等を含む液状の研磨剤の供給手段がある。
【００１７】
次に以上の構成からなるウェーハの研磨装置に関して、その作動状態について説明する。
先ず、保持部４１ａを移動して、ウェーハ２４を、バッキング材の表面からなる弾性薄膜３０の外側面に、水の表面張力によって吸着させる。そして、保持部４１ａを移動して、ウェーハ２４を定盤５６の研磨面６０上に位置させる。
次に、第１圧力室２０へ第１流体供給手段によって所定圧力の流体を供給することで、保持プレート１２全体を研磨面６０に追随させて押圧させる。押圧前に研磨面６０が保持プレート１２の面に対して傾いていても、流体圧の作用で研磨面６０に好適に追随させて、保持プレート１２の全面を均等に押圧できる。
そして、第２圧力室３２へ第２流体供給手段によって所定圧力の流体を供給することで、弾性薄膜３０を介して、より直接的に流体圧による等圧力を作用させ、ウェーハ２４の全面を研磨面へ均等に押圧できる。
すなわち、第１圧力室２０の圧力で保持プレート１２全体を研磨面６０へ均等な圧力で押圧し、保持プレート１２と定盤５６表面の平行度を高い精度で確保し、加えて、第２圧力室３２の圧力でウェーハ２４をより直接的に押圧できるため、さらに高い精度でウェーハ２４を研磨面６０へ均等に押圧できる。従って、ウェーハ２４全面を均一に研磨することができる。特に、表面を基準とする高精度な研磨に有効である。
【００１８】
また、第１圧力調整装置によって第１圧力室２０へ供給される流体の圧力を調整すること、および第２圧力調整装置によって第２圧力室３２へ供給される流体の圧力を調整することで、研磨条件を容易に変更できる。従って、ウェーハの研磨条件に応じて、第１圧力室２０および第２圧力室３２に作用する各圧力値、およびその圧力値のバランスを容易に調整でき、研磨装置の汎用性を向上できる。
【００１９】
また、第１圧力室２０と第２圧力室３２の２段の圧力室の作用で、ウェーハ２４を研磨面に押圧することができるため、研磨面６０の傾斜（面振れ）が比較的大きくても、その傾斜に好適に追随することができる。
さらに、板状の弾性部材１４と、弾性薄膜３０の２段で、ウェーハ２４にかかる捩じれ力を吸収することができるため、ウェーハ２４を研磨面６０へ、より好適に押圧できる。
なお、このウェーハの研磨装置によれば、前記ウェーハ以外の被研磨部材であるワーク（例えばガラス薄板材、水晶等の硬脆性材料の表面）も鏡面状に研磨することもできる。
【００２０】
以上に説明してきた実施例では、圧縮空気によって保持プレート１２を介してウェーハ４２を研磨面に押圧する場合を説明したが、他の流体圧例えば水圧または油圧を利用することもできる。
以上、本発明の好適な実施例について種々述べてきたが、本発明はこの実施例に限定されるものではなく、発明の精神を逸脱しない範囲内でさらに多くの改変を施し得るのは勿論のことである。
【００２１】
【発明の効果】
本発明によれば、第１圧力室の圧力で保持部材全体を研磨面へ均等な圧力で押圧し、保持部材と定盤表面の平行度を高い精度で確保し、加えて、第２圧力室の圧力でワークをより直接的に押圧できるため、さらに高い精度にワークを研磨面へ均等に押圧できる。これにより、ワーク全面を均一に研磨することができ、ワーク外周のダレを防止すると共に、ワーク表面の平坦度を向上できるという著効を奏する。
【図面の簡単な説明】
【図１】本発明に係る研磨装置の保持部の正面断面図。
【図２】図１の実施例の使用状態を示す要部を拡大した正面断面図。
【図３】従来の技術を示す断面図。
【符号の説明】
１０ヘッド部材
１２保持プレート
１４板状の弾性部材
１４ａ外側部
１４ｂ内側部
２０第１圧力室
２４ウェーハ
３０弾性薄膜
３２第２圧力室
３６連通路
４０テンプレート
４１ａ保持部
５６定盤
５８研磨布
６０研磨面[0001]
[Industrial application fields]
The present invention relates to a polishing apparatus, and more particularly, a polishing device including a holding unit that holds a workpiece, a surface plate having a polishing surface formed on a surface thereof, and a movement mechanism that relatively moves the holding unit and the surface plate. Relates to the device. As this polishing apparatus, for example, there is a wafer polishing apparatus used for mirror-polishing the wafer surface for semiconductor chips.
[0002]
[Prior art]
In recent years, with the progress of high integration of semiconductor devices, there has been a strict demand for improvement in flatness and surface quality of a silicon wafer as a substrate. In addition, there is an increasing demand for planarization with higher accuracy in polishing of interlayer insulating films and metal wirings deposited when devices are formed on the wafer surface. Therefore, a wafer polishing apparatus is required to be able to mirror-polish the wafer surface with higher accuracy or to perform high-precision polishing based on the surface.
[0003]
Conventionally, a wafer polishing apparatus has an air bag function for holding a wafer so that the entire surface of the wafer can be pressed against the polishing surface of the surface plate contacting the wafer surface with equal pressure. There is.
An example of the holding unit of the polishing apparatus will be described below with reference to FIG.
As shown in FIG. 3, a polishing cloth 58 made of a soft elastic member is bonded to a rotating surface plate 56 to form a polishing surface 60, and a holding portion 41 that can be rotated and moved up and down is provided above the polishing surface 60. Yes. The holding portion 41 includes a concave head member 11 that opens downward, an outer portion 13a that is fixed to the inner bottom surface of the head member 11, and an inner portion 13b that is referred to as a holding member (hereinafter referred to as a holding plate 17). A plate-like elastic member 13 that is fixed to the holding plate 17 and allows the movement of the holding plate 17 in an up and down direction and a horizontal direction within a minute range, and the inside of the head member 11 is held by the holding plate 17 and the plate shape. The pressure chamber 19 is a sealed space defined by the elastic member 13, and fluid supply means (not shown) for supplying a fluid having a predetermined pressure to the pressure chamber 19. Reference numeral 27 denotes a ring-shaped elastic member, which is an O-ring-shaped member formed of synthetic rubber or the like. The ring-shaped elastic member 27 is disposed between the outer peripheral surface of the holding plate 17 and the inner peripheral surface of the outer wall side portion 11a, and relative movement (for example, relative rotation) of the holding plate 17 with the head member 11 is performed. Acts to absorb and regulate.
[0004]
According to this polishing apparatus, the wafer surface held by water filling or the like on the holding plate 17 can quickly follow the inclination of the polishing surface 60 by the air bag action of the plate-like elastic member 13, and the wafer surface can be Even in the state of following the inclination of the polishing surface 60, the entire surface of the wafer can be pressed against the polishing surface 60 with an equal pressure. For this reason, the surface of the wafer can be suitably mirror-polished while maintaining high parallelism and flatness of the wafer 42. Note that a sheet-like backing material having a surface that is generally rich in adsorptivity is attached to the surface of the holding plate 17 so that the wafer 42 can be reliably filled with water.
[0005]
[Problems to be solved by the invention]
However, in the above wafer polishing apparatus, since the wafer is indirectly pressed through the holding plate, the flatness accuracy of the holding plate, the dimensional change due to deformation when pressure is applied to the holding plate, and There is a problem that it is easily affected by the accuracy of the thickness of the backing material, and it is difficult to polish the entire surface of the wafer with very high accuracy.
Further, there is a problem that the outer peripheral portion of the wafer tends to be polished, so that so-called outer peripheral sagging is likely to occur, and it is not possible to cope with the case where a very high accuracy flatness is required on the entire surface of the wafer.
[0006]
An object of the present invention is to provide a polishing apparatus capable of uniformly polishing the entire surface of the workpiece by pressing the entire surface of the workpiece evenly against the polishing surface, preventing sagging of the outer periphery of the workpiece, and improving the flatness of the workpiece surface. is there.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises the following arrangement.
That is, the present invention provides a polishing apparatus comprising: a holding unit that holds a workpiece; a surface plate having a polishing surface formed on a surface; and a motion mechanism that relatively moves the holding unit and the surface plate. A head member having a recess that opens downward, a holding member disposed inside the recess of the head member, an outer portion being fixed to the wall of the head member, and an inner portion being the holding member An elastic member that is fixed to the member and that suspends the holding member in an up and down direction and a horizontal direction in an allowable range, and the inside of the head member is defined by the holding member and the elastic member. The first pressure chamber provided is made of an elastic thin film, and is fixed to the outer surface of the holding member at the outer peripheral portion, and abuts against the workpiece on the outer surface so that the workpiece can be pressed against the polishing surface of the surface plate. Formed elastic thin film A second pressure chamber defined by an outer surface of the member and an inner surface of the elastic thin film, and a fluid having a predetermined pressure is supplied to the first pressure chamber by a first fluid supply means. A polishing apparatus, wherein a fluid having a predetermined pressure is supplied to the second fluid supply means.
[0008]
The first fluid supply means includes a first pressure adjusting device that adjusts the pressure of the fluid supplied to the first pressure chamber, and the second fluid supply means includes a fluid supplied to the second pressure chamber. The second pressure adjusting device that adjusts the pressure of the workpiece can be suitably adapted to various polishing conditions of the workpiece, and the versatility of the polishing device is improved.
[0009]
[Action]
According to the present invention, by supplying a fluid having a predetermined pressure to the first pressure chamber by the first fluid supply means, the entire holding member can be made to follow the inclination of the polishing surface, and the second pressure chamber can be moved to the second pressure chamber. By supplying a fluid of a predetermined pressure by the fluid supply means, it is possible to apply the equal pressure by the fluid pressure more directly through the elastic thin film and press the work against the polishing surface.
That is, the entire holding member is pressed against the polishing surface with equal pressure by the pressure in the first pressure chamber, and the parallelism between the holding member and the surface of the surface plate is ensured with high accuracy. Since the workpiece can be pressed more directly, the workpiece can be evenly pressed to the polishing surface with higher accuracy. Therefore, the entire work surface can be uniformly polished.
[0010]
【Example】
DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments when the present invention is applied to a wafer polishing apparatus will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a front sectional view showing a configuration of a holding unit 41a of a wafer polishing apparatus, and FIG. 2 is a front sectional view showing an enlarged main part when the wafer polishing apparatus of FIG. 1 is used.
Reference numeral 10 denotes a head member, which constitutes an outer portion of a holding portion that holds a wafer as a workpiece. The head member 10 is formed in a concave shape that opens downward. In this embodiment, the head member 10 is constituted by a flat plate wall portion 10b and a cylindrical side wall portion 10c, and the joining of the flat plate wall portion 10b and the cylindrical side wall portion 10c is airtight by an O-ring 11.
Reference numeral 12 denotes a holding plate, which is an embodiment of a holding member for holding a wafer. The holding plate 12 is disposed inside the concave portion of the head member 10.
[0011]
Reference numeral 14 denotes a plate-like elastic member which is an embodiment of the elastic member, and is formed in a donut shape by, for example, a hard rubber plate material (in this embodiment, cloth-containing nitrile rubber). The outer portion 14 a is fixed to the inner bottom surface of the head member 10 and the inner portion 14 b is fixed to the holding plate 12. Thereby, the plate-like elastic member 14 suspends the holding plate 12 in such a manner that the movement in the vertical direction and the horizontal direction is allowable within a minute range. The outer portion 14 a of the plate-like elastic member 14 is fixed to the inner bottom surface 10 a of the head member 10 by being clamped by the ring member 16 by tightening bolts (not shown). Further, the inner portion 14 b of the plate-like elastic member 14 is fixed to the holding plate 12 by being sandwiched between the pressing rings 18 by tightening bolts (not shown).
[0012]
Reference numeral 20 denotes a first pressure chamber, and the inside of the head member 10 is defined by a holding plate 12 and a plate-like elastic member 14. A fluid having a predetermined pressure is supplied into the first pressure chamber 20 by a first fluid supply means (not shown). Reference numeral 22 denotes a first pipe which communicates the pressure source of the first fluid supply means and the first pressure chamber 20. The first fluid supply means includes a first pressure adjusting device (not shown) that adjusts the pressure of the fluid supplied to the first pressure chamber 20.
Reference numeral 26 denotes a ring-shaped elastic member, for example, an O-ring-shaped member formed of rubber or the like. The ring-shaped elastic member 26 is disposed so as to contact both the outer peripheral surface of the holding plate 12 and the inner peripheral surface of the cylindrical side wall portion 10c, and allows the horizontal movement of the holding plate 12 within a minute range. doing. Thereby, it is possible to absorb the acting force in the horizontal direction (particularly the radial direction) generated when the wafer is polished.
[0013]
Reference numeral 30 denotes an elastic thin film made of an elastic thin film, and the outer peripheral portion 30b is fixed to the outer surface side of the holding plate 12 by being sandwiched between fixing rings 31 by tightening bolts (not shown). The elastic thin film 30 is provided so as to abut against the workpiece on the outer surface thereof and to press the workpiece evenly against the polishing surface of the surface plate by an air bag action. As this elastic thin film 30, what stuck together the sheet-like elastic material and the sheet-like backing material which has the surface rich in adsorptivity can be used. Moreover, the surface may have a property of a backing material, and the elastic material and the backing material may be combined so that the whole can act as an elastic material. By using the backing material in this way, the wafer 24 is reliably adhered to the surface of the elastic thin film 30 by the surface tension of a liquid such as water.
Reference numeral 32 denotes a second pressure chamber, which is defined by the outer side surface 12 a of the holding plate 12 and the inner side surface 30 a of the elastic thin film 30. A fluid having a predetermined pressure is supplied into the second pressure chamber 32 by a second fluid supply means (not shown). Note that the pressure source of the second fluid supply means communicates with the second pressure chamber 32 via the second pipe 33, the pipe joint 34, and the communication path 36.
The second fluid supply means is provided with a second pressure adjusting device (not shown) for adjusting the pressure of the fluid supplied to the second pressure chamber 32.
[0014]
A concave portion 28 is provided on the head member 10. A plurality of the recesses 28 are provided at predetermined intervals in the circumferential direction of the head member 10.
Reference numeral 38 denotes a pin-like member, and a plurality of members are erected on the holding plate 12 at predetermined intervals corresponding to the recesses 28. The pin-shaped member 38 is an aspect of a convex portion that is inserted into and engaged with the concave portion 28.
The pin-shaped member 38 includes a flange-shaped tip portion 38a, and movement is restricted between an inner bottom surface 28a that forms the recess 28 and an inner diameter portion 28b. Thereby, the vertical movement of the holding plate 12 is restricted.
Further, the tip end portion 38a of the pin-shaped member acts as an engaging portion that engages with the concave portion 28 in a loosely movably fitted state within a predetermined minute range. Therefore, the relative movement of the head member 10 and the holding plate 12 in a minute range is allowed, and the combined force acting on the plate-like elastic member 14 can be reduced. Thereby, it can prevent that a plate-shaped elastic member is damaged, and can prevent the fall of an air bag function as a result.
In this embodiment, a pin-shaped member 38 (engagement portion) is provided on the holding plate 12 (holding member) side, and a recess 28 (engaged portion) is provided on the head member 10 side. In addition, an engaged portion may be provided on the holding member, and an engaging portion may be provided on the head member 10 side.
[0015]
Reference numeral 40 denotes a template, which is attached to the outer surface side (lower surface) of the elastic thin film 30 and is formed so as to be able to surround the wafer 24, and prevents the wafer from slipping. The thickness of the template 40 is set to be equal to the thickness of the wafer 24 (in this embodiment, it is provided slightly thinner than the thickness of the wafer 24). A plurality of grooves may be provided on the surface of the template 40 so that the abrasive (liquid abrasive containing abrasive grains) is suitably supplied into the template 40.
By providing the template 40 in this way, the holding plate 12 is received by the polishing surface 60 of the surface plate 56 by the template 40 (see FIG. 2), so that it is possible to prevent the outer periphery of the wafer 24 from sagging.
[0016]
In addition to the above-described wafer holding unit, and a pressing unit that is provided in the wafer holding unit and presses the wafer 24 against the polishing surface 60 with a predetermined pressing force, as a basic configuration of the wafer polishing apparatus, A surface plate 56 (see FIGS. 2 and 3) having a polishing surface 60 formed on the surface, and contact / separation means for moving the wafer holding portion and the surface plate 56 in contact with and separate from each other in order to bring the wafer surface into contact with the polishing surface 60. , A driving means for moving the wafer 24 and the surface plate 56 relative to each other by rotation and / or reciprocation while the wafer 24 is in contact with and pressed against the polishing surface 60; There is.
[0017]
Next, the operation state of the wafer polishing apparatus having the above configuration will be described.
First, the holding part 41a is moved, and the wafer 24 is adsorbed to the outer surface of the elastic thin film 30 made of the surface of the backing material by the surface tension of water. Then, the holding unit 41 a is moved to place the wafer 24 on the polishing surface 60 of the surface plate 56.
Next, by supplying a fluid of a predetermined pressure to the first pressure chamber 20 by the first fluid supply means, the entire holding plate 12 is caused to follow the polishing surface 60 and be pressed. Even if the polishing surface 60 is inclined with respect to the surface of the holding plate 12 before pressing, the entire surface of the holding plate 12 can be pressed evenly by suitably following the polishing surface 60 by the action of fluid pressure.
Then, by supplying a fluid of a predetermined pressure to the second pressure chamber 32 by the second fluid supply means, an equal pressure due to the fluid pressure is applied more directly through the elastic thin film 30, and the entire surface of the wafer 24 is polished. It can be pressed evenly onto the surface.
That is, the entire holding plate 12 is pressed against the polishing surface 60 with the pressure of the first pressure chamber 20 with a uniform pressure, and the parallelism between the holding plate 12 and the surface of the surface plate 56 is ensured with high accuracy. Since the wafer 24 can be pressed more directly by the pressure in the chamber 32, the wafer 24 can be pressed evenly onto the polishing surface 60 with higher accuracy. Therefore, the entire surface of the wafer 24 can be uniformly polished. In particular, it is effective for high-precision polishing based on the surface.
[0018]
Further, by adjusting the pressure of the fluid supplied to the first pressure chamber 20 by the first pressure adjusting device, and by adjusting the pressure of the fluid supplied to the second pressure chamber 32 by the second pressure adjusting device, Polishing conditions can be easily changed. Therefore, the pressure values acting on the first pressure chamber 20 and the second pressure chamber 32 and the balance of the pressure values can be easily adjusted according to the polishing conditions of the wafer, and the versatility of the polishing apparatus can be improved.
[0019]
Further, since the wafer 24 can be pressed against the polishing surface by the action of the two pressure chambers of the first pressure chamber 20 and the second pressure chamber 32, the inclination (surface runout) of the polishing surface 60 is relatively large. Can follow the inclination suitably.
Furthermore, since the twisting force applied to the wafer 24 can be absorbed by the two stages of the plate-like elastic member 14 and the elastic thin film 30, the wafer 24 can be more suitably pressed against the polishing surface 60.
In addition, according to this wafer polishing apparatus, a workpiece (for example, a surface of a hard brittle material such as a glass thin plate material or crystal) that is a member to be polished other than the wafer can also be polished into a mirror surface.
[0020]
In the embodiment described above, the case where the wafer 42 is pressed against the polishing surface by the compressed air via the holding plate 12 has been described. However, other fluid pressures such as water pressure or hydraulic pressure may be used.
The preferred embodiments of the present invention have been described above in various ways. However, the present invention is not limited to these embodiments, and it goes without saying that many more modifications can be made without departing from the spirit of the invention. That is.
[0021]
【The invention's effect】
According to the present invention, the entire holding member is pressed against the polishing surface with equal pressure by the pressure of the first pressure chamber, the parallelism between the holding member and the surface plate surface is ensured with high accuracy, and in addition, the second pressure chamber Since the workpiece can be pressed more directly with this pressure, the workpiece can be pressed evenly onto the polishing surface with higher accuracy. As a result, the entire surface of the workpiece can be uniformly polished, preventing the sagging of the outer periphery of the workpiece and improving the flatness of the workpiece surface.
[Brief description of the drawings]
FIG. 1 is a front sectional view of a holding part of a polishing apparatus according to the present invention.
2 is an enlarged front cross-sectional view showing a main part showing a use state of the embodiment of FIG. 1;
FIG. 3 is a cross-sectional view showing a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Head member 12 Holding plate 14 Plate-like elastic member 14a Outer part 14b Inner part 20 First pressure chamber 24 Wafer 30 Elastic thin film 32 Second pressure chamber 36 Communication path 40 Template 41a Holding part 56 Surface plate 58 Polishing cloth 60 Polishing surface

Claims

In a polishing apparatus comprising a holding unit that holds a workpiece, a surface plate having a polishing surface formed on a surface, and a movement mechanism that relatively moves the holding unit and the surface plate,
The holding part is
A head member having a recess that opens downward;
A holding member disposed inside the concave portion of the head member;
An elastic member having an outer portion fixed to the wall portion of the head member and an inner portion fixed to the holding member, and suspending the holding member in an up and down direction and in a horizontal range so as to be allowable. When,
A first pressure chamber provided by defining the inside of the head member by the holding member and the elastic member;
An elastic thin film made of an elastic thin film, fixed at the outer peripheral portion on the outer surface side of the holding member, and in contact with the work on the outer face so that the work can be pressed against the polishing surface of the surface plate;
A second pressure chamber defined by an outer surface of the holding member and an inner surface of the elastic thin film,
A polishing apparatus, wherein a fluid having a predetermined pressure is supplied to the first pressure chamber by a first fluid supply means, and a fluid having a predetermined pressure is supplied to the second pressure chamber by a second fluid supply means.

The first fluid supply means is provided with a first pressure adjusting device for adjusting the pressure of the fluid supplied to the first pressure chamber, and the second fluid supply means has a pressure of the fluid supplied to the second pressure chamber. The polishing apparatus according to claim 1, further comprising a second pressure adjusting device for adjusting the pressure.