JP4477784B2

JP4477784B2 - Placement mechanism of workpiece

Info

Publication number: JP4477784B2
Application number: JP2001027237A
Authority: JP
Inventors: 哲也斉藤
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 2001-02-02
Filing date: 2001-02-02
Publication date: 2010-06-09
Anticipated expiration: 2021-02-02
Also published as: JP2002231794A

Description

【０００１】
【発明の属する技術分野】
本発明は、例えばチタン（Ｔｉ）膜、窒化チタン（ＴｉＮ）膜等の薄膜を被処理体表面に成膜する成膜装置に用いられる被処理体の載置機構に関し、更に詳しくは、被処理体の裏面での成膜用ガスの堆積を防止することができる被処理体の載置機に関する。
【０００２】
【従来の技術】
半導体製造工程には配線膜やバリヤ膜を成膜する工程がある。バリヤ膜は配線膜の配線材料（例えば、銅、タングステン、アルミニウム等）とシリコンとの反応を防止する薄膜で、その材料として例えば電気抵抗が小さく、耐食性に優れたＴｉ、ＴｉＮ等の金属材料が汎用されている。この成膜工程では配線膜の種類に即して種々の成膜装置が用いられる。例えばバリヤ膜を成膜する場合には、極めて薄いＴｉ膜をプラズマＣＶＤにより成膜し、このＴｉ膜を窒化処理し、更に、ＴｉＣｌ４とアンモニアガスを用いて熱ＣＶＤでＴｉＮ膜を成膜している。また、成膜処理に先立って被処理体（例えば、ウエハ）を載置する載置体等の表面にＴｉＮのプリコート膜を施し、載置体上のウエハ面内の熱的均一性を保持すると共に載置体等に起因する金属汚染等を防止している。
【０００３】
而して、例えばＴｉＮ膜の成膜処理には図６に示す成膜装置が用いられる。この成膜装置は、同図に示すように、処理容器１と、この処理容器１内に配置された載置機構２とを備えている。処理容器１の上部には成膜用ガスのガス供給部１Ａが形成され、下部には成膜後のガスを排気する排気部１Ｂが形成されている。また、載置機構２はウエハＷを載置する載置体（サセプタ）２Ａと、サセプタ２Ａ上でウエハＷを授受する複数のリフタピン２Ｂと、これらのリフタピン２Ｂが垂直に固定されたアーム２Ｃと、このアーム２Ｃを昇降させる昇降駆動機構（例えば、エアシリンダ）２Ｄとを備えている。また、図６、図７に示すようにサセプタ２Ａには複数のリフタピン２Ｂに対応する貫通孔２Ｅが形成され、各貫通孔２Ｅにはリフタピン２Ｂがそれぞれ貫通している。
【０００４】
ところで、サセプタ２Ａ上にウエハＷを載置してＴｉＮ膜を成膜する場合には、通常サセプタ２Ａを内蔵ヒータ２Ｆで加熱してウエハＷを例えば６５０〜６８０℃で成膜処理するため、サセプタ２Ａとアーム２Ｃが熱膨張する。ところが、サセプタ２Ａとアーム２Ｃはそれぞれ異なる材料によって形成されているため、両者２Ａ、２Ｃ間で熱膨張に差が生じる。そのため、図７の（ａ）に示すように貫通孔２Ｅの内径は両者２Ａ、２Ｃ間の熱膨張を吸収する大きさに設定され、成膜処理時の高温下で両者２Ａ、２Ｃが熱膨張しても図７の（ｂ）に示すように熱膨張差を貫通孔２Ｅで吸収して一点鎖線位置から実線位置まで偏倚するようにしてある。
【０００５】
【発明が解決しようとする課題】
しかしながら、従来に被処理体の載置機構の場合には、貫通孔２Ｅの内径がリフタピン２Ｂの外径より大きく設定され、両者２Ａ、２Ｃ間に大きな隙間があるため、成膜処理時に成膜用ガスが図７の（ａ）に矢印で示すようにサセプタ２Ａの下面からリフタピン２Ｂと貫通孔２Ｅ間の隙間を通ってウエハＷの裏面に達し、ウエハＷの裏面や貫通孔２Ｅの内周面に成膜用ガスの反応生成物等が堆積し、この堆積物がパーティクルの発生源になる虞がある。また、堆積物が原因となってリフタピン２Ｂが貫通孔２Ｅで固着し、リフタピン２Ｂの動作不良をもたらす虞もある。
【０００６】
尚、特開平６−３１８６３０号公報には上述と同種の課題を解決した発明について記載されているが、機構的に複雑で、コスト的に高くなりがちである。
【０００７】
本発明は、上記課題を解決するためになされたもので、被処理体の裏面での堆積物の生成を確実に防止すると共に被処理体の処理時に常にリフタピンを円滑に動作させることができ、しかも簡単な機構で安価に実現することができる被処理体の載置機構を提供することを目的としている。
【０００８】
【課題を解決するための手段】
本発明の請求項１に記載の被処理体の載置機構は処理容器内に配置され且つこの処理容器内に供給された成膜用ガスで成膜するための被処理体を載置する載置体と、この載置体に形成された複数の貫通孔にそれぞれ挿入され且つ上記被処理体を上記載置体上で受け渡すための複数のリフタピンと、これらのリフタピンを支持する支持体と、この支持体を介して上記各リフタピンを昇降させる昇降機構とを備えた載置機構において、上記リフタピンを上記支持体上に載置すると共に、上記リフタピンと上記貫通孔の隙間を上記成膜用ガスが実質的に上記載置体の下面側から上面側へ通過しない隙間として設定し、また、上記リフタピンの基端が遊嵌する凹部を上記支持体上に設けたことを特徴とするものである。
【０００９】
また、本発明の請求項２に記載の被処理体の載置機構は、処理容器内に配置され且つこの処理容器内に供給された成膜用ガスで成膜するための被処理体を載置する載置体と、この載置体に形成された複数の貫通孔にそれぞれ挿入され且つ上記被処理体を上記載置体上で受け渡すための複数のリフタピンと、これらのリフタピンを支持する支持体と、この支持体を介して上記各リフタピンを昇降させる昇降機構とを備えた載置機構において、上記各貫通孔の上端に上記載置体の凹陥部をそれぞれ連設すると共に上記各貫通孔に軸部を嵌入して上記貫通孔を閉じる蓋部材を上記各凹陥部にそれぞれ載置し、且つ、上記各リフタピンの上端を上記貫通孔内に挿入すると共に上記リフタピンを上記支持体上に載置し、更に、上記リフタピンの基端が遊嵌する凹部を上記支持体上に設けたことを特徴とするものである。
【００１１】
また、本発明の請求項３に記載の被処理体の載置機構は、請求項１または請求項２に記載の発明において、上記リフタピンの基端からの高さを調整可能にしたことを特徴とするものである。
【００１２】
また、本発明の請求項４に記載の被処理体の載置機構は、請求項１〜請求項３のいずれか１項に記載の発明において、上記載置体にプリコート膜を設けたことを特徴とするものである。
【００１３】
また、本発明の請求項５に記載の被処理体の載置機構は、請求項１〜請求項４のいずれか１項に記載の発明において、上記貫通孔の軸方向長さと、上記貫通孔の内径と上記リフタピンまたは上記蓋部材の軸部の外径の差とに基づくアスペクト比を少なくとも３０以上に設定したことを特徴とするものである。
【００１４】
【発明の実施の形態】
以下、図１〜図５に示す実施形態に基づいて本発明を説明する。
本実施形態の被処理体の載置機構１０は、図１に示すように、処理容器２０内に配置された載置体（サセプタ）１１と、このサセプタ１１上で被処理体（例えば、ウエハ）Ｗを受け渡す複数のリフタピン１２と、これらのリフタピン１２を支持する支持体（アーム）１３と、このアーム１３を昇降駆動させる昇降駆動機構（例えば、エアシリンダ）１４とを備えている。処理容器２０は例えばアルマイト加工されたアルミニウムによって形成され、その上部には成膜用ガスをシャワー状にして供給する中空状のガス供給部２１が処理容器２０と一体的に形成されている。このガス供給部２１の上面には成膜用ガスの供給部２１Ａが形成され、そのサセプタ１１との対向面２１Ｂ全面には成膜用ガスをシャワー状にして供給する多数のガス供給孔２１Ｃが均等に分散して形成されている。
【００１５】
上記サセプタ１１は例えば窒化アルミニウム等のセラミックによって形成され、、支持柱１５によって水平に支持されている。サセプタ１１の内部にはヒータ１６が埋設され、ヒータ１６を介してウエハＷを所定の成膜温度まで加熱し維持するようにしている。リフタピン１２は例えばアルミナ等のセラミックによって形成され、サセプタ１１に形成された貫通孔１１Ａ内に挿入されている。アーム１３は例えばリフタピン１２と同様にアルミナによってリング状に形成されている。このアーム１３はエアシリンダ１４のロッド１４Ａに連結され、ロッド１４Ａで水平に支持されている。
【００１６】
ところで、上記リフタピン１２は、図１に示すように、下降端に位置する時には上端が少なくとも貫通孔１１Ａ内に位置し、ウエハＷの受け渡しを行う時には図２に示すようにエアシリンダ１４を介して貫通孔１１Ａから突出してウエハＷをサセプタ１１の上方で支持する。また、リフタピン１２は、図１、図２に示すように、アーム１３上面にリフタピン１２の基端部の断面形状に即して形成された凹陥部１３Ａ内に載置されている。従って、リフタピン１２はアーム１３の凹陥部１３Ａ内で自重により支持されている。また、リフタピン１２はシムＳによって高さを微調整できるようにしてある。
【００１７】
上記凹陥部１３Ａは、成膜処理時の高温下でサセプタ１１とアーム１３間に熱膨張差を吸収できる大きさに形成され、熱処理時にサセプタ１１とアーム１３間で熱膨張差が生じてもリフタピン１２が凹陥部１３Ａ内で位置ずれするようになっている。このようにサセプタ１１とアーム１３間の熱膨張差を凹陥部１３Ａ内で吸収するようにしてあるため、本実施形態では従来のようにサセプタ１１の貫通孔１１Ａ内径をリフタピン１２の外径より大きく設定する必要はない。従って、本実施形態では貫通孔１１Ａは単にリフタピン１２の昇降ガイドとして利用するため、貫通孔１１Ａとリフタピン１２間の隙間は成膜用ガスが実質的に通過できず、リフタピン１２が貫通孔１１Ａにおいて昇降できる極力狭い隙間に設定されている。
【００１８】
そこで、上記隙間と成膜用ガスの通過の関係について検討した結果、隙間を以下のように設定すれば良いことが判った。即ち、図３に示すように、上記貫通孔１１Ａの内径をＤ、リフタピン１２の外径をｄ及び貫通孔１１Ａの厚さ（本実施形態では貫通孔の上端に凹陥部（座ぐり）が形成されているため、凹陥部の底面からサセプタ１１の下面までの長さ）をｔとして設定し、サセプタ１１の厚さｔと隙間（（Ｄ−ｄ）／２）との関係をアスペクト比（ｔ／〔（Ｄ−ｄ）／２〕）として定義して隙間におけるガス通過を観察すると、アスペクト比を少なくとも３０、より好ましくは８０〜１００に設定すれば、隙間における成膜用ガスの通過を防止することができ、ひいてはウエハＷ裏面での成膜用ガスの反応生成物の堆積を防止してパーティクルの発生源を無くし、更に、貫通孔１１Ａ内における反応生成物の付着を防止して貫通孔１１Ａにおけるリフタピン１２の固着を防止することができる。
【００１９】
以上説明したように本実施形態によれば、リフタピン１２をアーム１３上に載置すると共に、リフタピン１２と貫通孔１１Ａの隙間を成膜用ガスが実質的にサセプタ１１の下面側から上面側へ通過しない大きさ、より具体的には隙間とサセプタ１１の厚さのアスペクト比を少なくとも３０、より好ましくは８０〜１００に設定したため、成膜処理時にウエハＷの裏面や貫通孔１１Ａ内での反応生成物の堆積を防止してパーティクルの発生源を無くすると共に貫通孔１１Ａでのリフタピン１２の固着を防止することができる。従って、成膜処理時には常にリフタピン１２が円滑に作動し、成膜処理前後のウエハＷの受け渡しを円滑に行うことができる。しかも、リフタピン１２をアーム１３上に載置するだけの構造であるため、コスト的にも従来のものと殆ど変わらず、低コストで実現することができ、また、従来の載置機構の構造に少し手を加えるだけで本実施形態の載置機構１０を得ることができる。
【００２０】
また、図４は本発明の他の実施形態を示す要部断面図である。本実施形態ではサセプタ１１の全面にプリコート膜１７を施した以外は上記実施形態に準じて構成されている。プリコート膜１７はウエハＷの成膜処理に先立って成膜用ガスを用いて処理容器２０内に例えばＴｉＮ膜を施すことによって形成される薄膜である。このようにプリコート膜を施すことにより成膜用ガスが貫通孔１１Ａの隙間を殆ど通過せず、ウエハＷの裏面まで達しなくなる。その理由は、ウエハＷへの成膜処理時に成膜用ガスが貫通孔１１Ａの下端開口（入口）近傍のプリコート膜１７と直に反応して入口近傍における成膜用ガスの殆どが消費され、貫通孔１１Ａ内で成膜用ガスの濃度勾配が急激に低下するためと考えられる。従って、上述のようにアスペクト比を設定した上で成膜処理に先立ってサセプタ１１全面にプリコート膜１７を設けることで、成膜プロセス条件によってはウエハＷ裏面等における反応生成物の堆積及びリフタピン１２の固着をより確実に防止することができる。
【００２１】
また、図５の（ａ）、（ｂ）は本発明の更に他の実施形態を示す図である。本実施形態では、貫通孔１１Ａに蓋部材１８を設け、この蓋部材１８をリフタピン１２で突き上げるようにしたものである。そして、サセプタ１１の貫通孔１１Ａの上端開口には凹陥部１１Ｂが連設され、貫通孔１１Ａの軸心と凹陥部１１Ｂの軸心は互いに一致している。その他は図１〜図３に示す実施形態に準じて構成されている。
【００２２】
而して、上記蓋部材１８は、図５の（ａ）、（ｂ）に示すように、キャップ部１８Ａと、このキャップ部１８Ａの下面に連設された軸部１８Ｂとからなっている。キャップ部１８Ａの直径は貫通孔１１Ａの直径より大径で凹陥部１１Ｂの直径より小径に形成され、軸部１８Ｂの直径は貫通孔１１Ａの直径より小径に形成されている。そして、キャップ部１８Ａの下面と凹陥部１１Ｂの底面は互いに密着するように形成されている。キャップ部１８Ａと凹陥部１１Ｂの底面は互いに密着すれば、平坦面、テーパ面等の如何なる形態であっても良い。また、軸部１８Ｂは中空状に形成され、この中空部にリフタピン１２の先端が嵌入している。従って、蓋部材１８は、軸部１８Ｂが貫通孔１１Ａ内に嵌入すると共にキャップ部１８Ａで貫通孔１１Ａの上端開口を閉じている。キャップ部１８Ａは軸部１８Ｂが貫通孔１１Ａ内で偏っても貫通孔１１Ａの上端開口を閉じる大きさに形成されている。軸部１８Ｂと貫通孔１１Ａの隙間は貫通孔１１Ａ内での反応生成物の付着を防止するために上記各実施形態の隙間が好ましい。
【００２３】
また、上記リフタピン１２は、例えば、小径部１２Ａと、大径部１２Ｂと、これら両者を繋ぐ連結部１２Ｃからなっている。小径部１２Ａの直径は蓋部材１８の軸部１８Ｂの中空部に嵌入するように形成され、連結部１２Ｃは小径部１２Ａから大径部１２Ｂへと徐々に太くなるように形成されている。小径部１２Ａの先端は軸部１８Ｂの最奥部に達しているが、貫通孔１１Ａが十分に長い場合には達していなくても良く、リフタピン１２で蓋部材１８をサセプタ１１の上方へ突き上げることができれば良い。従って、蓋部材１８の軸部１８Ｂは中空状でなくても良い。軸部１８Ｂが中空でない場合には、軸部１８Ｂの下端が貫通孔１１Ａの下端に達することなく、貫通孔１１Ａの下端の空間にリフタピン１２を挿入でき、リフタピン１２、蓋部材１８の昇降によって抜け落ちなければ良い。リフタピン１２も上記各実施形態と同様にアーム１３の凹陥部１３Ａ内に載置されている。従って、本実施形態によれば、蓋部材１８のキャップ部１８Ａで貫通孔１１Ａを閉じることができるため、上記各実施形態と同様の作用効果を期することができる。尚、本実施形態の場合にはサセプタ１１にプリコート膜を設けなくてもウエハＷ裏面への堆積物の生成等を確実に防止することができる。
【００２４】
【実施例】
次に、実施例に基づいてアスペクト比やプリコート膜の作用効果について具体的に説明する。
【００２５】
実施例１
本実施例では、まず下記サセプタにプリコート膜を設けた。この際、２００ｍｍ用のサセプタを使用し、サセプタの貫通孔としては下記の一種類で、リフタピンとしては下記の三種類を使用した。次いで、ウエハにＴｉＮ膜を施したが、この成膜プロセスではウエハの裏面に成膜用ガスの反応生成物を確実に堆積させるために、通常のウエハへの成膜厚（２０ｎｍ）に要する処理時間の５倍の時間（５分）でプロセス圧力も十分に高い高圧プロセス条件でウエハにＴｉＮ膜を施した。そして、成膜後にウエハ裏面での貫通孔における堆積物（ピン孔跡）の有無を目視観察し、その結果を下記表１にピン孔跡の有無として示した。尚、表１には三種類のリフタピンは、蓋部材の無い二種類のリフタピンをストレートピン▲１▼、▲２▼として、蓋部材の有るリフタピンを蓋付きピンとして示した。
［サセプタの条件］
▲１▼サセプタ厚：１７．０ｍｍ
▲２▼凹陥部深さ：３．１ｍｍ
▲３▼貫通孔直径：４．０ｍｍ
▲４▼リフタピン：
ストレートピン▲１▼の直径＝３．６ｍｍ
ストレートピン▲２▼の直径＝３．４ｍｍ
蓋付きピンの軸部の直径＝３．６ｍｍ
【００２６】
実施例２
本実施例では実施例１と同一のサセプタを使用し、サセプタにはプリコート膜を設けなかった。そして、ウエハにＴｉＮ膜を施したが、この成膜プロセスでは成膜時間が５分でプロセス圧力は比較的低い低圧プロセス条件でウエハに成膜処理を施した後、実施例１と同様にピン孔跡の有無を目視観察し、その結果を下記表１に示した。
【００２７】
［比較例１］
本比較例では実施例１と同一のサセプタを使用し、サセプタにプリコート膜を設けずに、実施例１と同一の高圧プロセス条件で成膜処理を施した後、実施例１と同様にピン孔跡の有無を目視観察し、その結果を下記の表１に示した。
【００２８】
【表１】

【００２９】
上記表１に示す結果によれば、プリコート膜を設けた実施例１の場合にはストレートピン▲１▼、▲２▼共に一枚目のウエハからピン孔跡が確認されなかった。つまり、アスペクト比が７０であるストレートピン▲１▼、アスペクト比が４６であるストレートピン▲２▼のいずれの場合にもピン孔跡が無く、堆積物の生成が認められなかった。これに対して、プリコート膜を設けない比較例１の場合にはストレートピン▲１▼に３枚目のウエハまでピン孔跡が確認された。この比較例１ではストレートピン▲２▼についてのデータはないが、ストレートピン▲２▼はストレートピン▲１▼よりも隙間が大きくなることからピン孔跡が認められると推定される。
【００３０】
これらのことから、サセプタにプリコート膜が施されている場合には、ウエハに成膜処理を施す時に貫通孔の入口近傍のプリコート膜において成膜用ガスが反応して貫通孔内での濃度勾配が急激に低下し、ウエハまで達しないと推定される。これに対して、プリコート膜のない場合には、ウエハへの成膜時にサセプタでの成膜反応に潜伏時間（INCUBATION TIME）があって未反応の成膜用ガスが消費しきれずに貫通孔を通過してウエハ裏面に堆積物が生成するものと推定される。また、実施例１の蓋付きピンの場合には当然のことではあるがピン孔跡が確認されなかった。
【００３１】
一方、プリコート膜のないサセプタを用いて低圧プロセス条件でウエハに成膜処理を施した場合には、上記表１の結果からも明らかなようにストレートピン▲２▼の場合でも一枚目のウエハからウエハ裏面にピン孔跡が確認されなかった。ストレートピン▲１▼については確認してないが、隙間の大きなストレートピン▲２▼でピン孔跡が確認されないことから、ストレートピン▲１▼の場合でもウエハの裏面に堆積物が生成しないものと推定される。つまり、低圧プロセスであれば、ストレートピンのアスペクト比が４６もあれば、ウエハ裏面に堆積物が生成されないことが判った。
【００３２】
尚、本発明は上記各実施形態に何等制限されるものではない。例えば、上記実施形態ではアーム上にリフタピンを載置する凹陥部を設けた場合について説明したが、この凹陥部は設けなくても良い。要は、リフタピンを支持体上に載置し、リフタピンと貫通孔との隙間をリフタピンが昇降し得る最小限の隙間に設定してあれば良い。
【００３３】
【発明の効果】
本発明によれば、被処理体の裏面での堆積物の生成を確実に防止すると共に被処理体の処理時に常にリフタピンを円滑に動作させることができ、しかも簡単な機構で安価に実現することができる被処理体の載置機構を提供することができる。
【図面の簡単な説明】
【図１】本発明の被処理体の載置機構の一実施形態の要部を示す断面図である。
【図２】図１に示すサセプタ上でウエハを受け渡す時のリフタピンとウエハとの関係を示す部分断面図である。
【図３】リフタピンと隙間のアスペクト比を説明するための断面図である。
【図４】図１に示すサセプタにプリコート膜を設けた状態を拡大して示す模式図である。
【図５】本発明の被処理体の載置機構の他の実施形態の要部を拡大して示す断面図で、（ａ）はウエハを受け渡す状態を示す図、（ｂ）はウエハをサセプタ上に載置した状態を示す図である。
【図６】従来の成膜装置の断面構造を示す概念図である。
【図７】図１に示すサセプタとリフタピンの関係を示す要部断面図で、（ａ）は常温状態を示す図、（ｂ）は成膜処理時を示す図である。
【符号の説明】
１０被処理体の載置機構
１１サセプタ
１１Ａ貫通孔
１１Ｂ凹陥部
１２リフタピン
１３アーム（支持体）
１３Ａ凹陥部
１４昇降駆動機構
１８蓋部材
１８Ａキャップ部
１８Ｂ軸部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mounting mechanism for a target object used in a film forming apparatus for forming a thin film such as a titanium (Ti) film or a titanium nitride (TiN) film on the surface of the target object. The present invention relates to a placement machine for an object to be processed that can prevent deposition of a deposition gas on the back surface of the body.
[0002]
[Prior art]
The semiconductor manufacturing process includes a process of forming a wiring film or a barrier film. The barrier film is a thin film that prevents the reaction between the wiring material of the wiring film (for example, copper, tungsten, aluminum, etc.) and silicon. As the material, for example, a metal material such as Ti or TiN that has low electrical resistance and excellent corrosion resistance is used. It is widely used. In this film forming process, various film forming apparatuses are used according to the type of the wiring film. For example, when forming a barrier film, an extremely thin Ti film is formed by plasma CVD, this Ti film is nitrided, and further a TiN film is formed by thermal CVD using TiCl4 and ammonia gas. Yes. Prior to the film forming process, a TiN precoat film is applied to the surface of a mounting body or the like on which an object to be processed (for example, a wafer) is mounted to maintain thermal uniformity within the wafer surface on the mounting body. At the same time, metal contamination caused by the mounting body is prevented.
[0003]
Thus, for example, the film forming apparatus shown in FIG. 6 is used for the film forming process of the TiN film. As shown in FIG. 1, the film forming apparatus includes a processing container 1 and a mounting mechanism 2 disposed in the processing container 1. A gas supply unit 1A for forming a film is formed in the upper part of the processing container 1, and an exhaust unit 1B for exhausting the gas after film formation is formed in the lower part. The mounting mechanism 2 includes a mounting body (susceptor) 2A for mounting the wafer W, a plurality of lifter pins 2B for transferring the wafer W on the susceptor 2A, and an arm 2C to which these lifter pins 2B are fixed vertically. And an elevating drive mechanism (for example, an air cylinder) 2D for elevating and lowering the arm 2C. As shown in FIGS. 6 and 7, through holes 2E corresponding to a plurality of lifter pins 2B are formed in the susceptor 2A, and the lifter pins 2B penetrate the respective through holes 2E.
[0004]
By the way, when the wafer W is placed on the susceptor 2A to form a TiN film, the susceptor 2A is normally heated by the built-in heater 2F to form the wafer W at, for example, 650 to 680 ° C. 2A and arm 2C are thermally expanded. However, since the susceptor 2A and the arm 2C are made of different materials, there is a difference in thermal expansion between the two

susceptors

2A and 2C. Therefore, as shown in FIG. 7A, the inner diameter of the through hole 2E is set to a size that absorbs the thermal expansion between the two 2A and 2C, and the two 2A and 2C are thermally expanded at a high temperature during the film forming process. Even so, as shown in FIG. 7B, the difference in thermal expansion is absorbed by the through-hole 2E so as to deviate from the one-dot chain line position to the solid line position.
[0005]
[Problems to be solved by the invention]
However, in the case of a conventional mechanism for placing an object to be processed, the inner diameter of the through hole 2E is set larger than the outer diameter of the lifter pin 2B, and there is a large gap between the two

holes

2A and 2C. As shown by an arrow in FIG. 7A, the working gas reaches the back surface of the wafer W from the lower surface of the susceptor 2A through the gap between the lifter pin 2B and the through hole 2E, and the back surface of the wafer W and the inner periphery of the through hole 2E. There is a possibility that a reaction product of the film forming gas accumulates on the surface, and this deposit becomes a generation source of particles. Further, the lifter pin 2B is fixed by the through-hole 2E due to the deposit, and there is a possibility that the lifter pin 2B may malfunction.
[0006]
Japanese Patent Application Laid-Open No. 6-318630 describes an invention that solves the same kind of problem as described above, but it is mechanically complex and tends to be expensive.
[0007]
The present invention was made in order to solve the above-described problem, and can reliably prevent the formation of deposits on the back surface of the object to be processed and can smoothly operate the lifter pin at all times during the processing of the object to be processed . In addition, an object of the present invention is to provide a placement mechanism for an object to be processed that can be realized with a simple mechanism at low cost.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a mounting mechanism for mounting a target object that is disposed in a processing container and for forming a film with a film forming gas supplied into the processing container. A mounting body, a plurality of lifter pins which are respectively inserted into a plurality of through holes formed in the mounting body and deliver the object to be processed on the mounting body, and a support body which supports the lifter pins. The mounting mechanism includes a lifting mechanism that lifts and lowers each of the lifter pins through the support. The lifter pin is mounted on the support and the gap between the lifter pin and the through hole is used for the film formation. The gap is set so that gas does not substantially pass from the lower surface side to the upper surface side of the mounting body, and a concave portion in which the base end of the lifter pin is loosely fitted is provided on the support body. is there.
[0009]
According to a second aspect of the present invention, there is provided a mounting mechanism for an object to be processed, which is disposed in the processing container and for forming a film with the film forming gas supplied into the processing container. A mounting body to be placed, a plurality of lifter pins that are respectively inserted into a plurality of through holes formed in the mounting body and deliver the object to be processed on the mounting body, and support the lifter pins In the mounting mechanism comprising a support and a lifting mechanism that lifts and lowers each lifter pin through the support, the recessed portion of the mounting body is connected to the upper end of each through-hole, and A lid member that inserts a shaft portion into the hole and closes the through hole is placed in each recessed portion, and the upper end of each lifter pin is inserted into the through hole, and the lifter pin is placed on the support. placed, further, the base end of the lifter pin is Yu A recess is characterized in that provided on the support.
[0011]
According to a third aspect of the present invention, there is provided a mechanism for placing an object to be processed, wherein the height from the base end of the lifter pin can be adjusted in the first or second aspect of the invention. It is what.
[0012]
According to a fourth aspect of the present invention, there is provided a mechanism for placing an object to be processed according to the invention described in any one of the first to third aspects, wherein a precoat film is provided on the upper body. It is a feature.
[0013]
In addition, according to a fifth aspect of the present invention, there is provided the workpiece mounting mechanism according to any one of the first to fourth aspects, wherein the axial length of the through hole and the through hole are the same. The aspect ratio is set to at least 30 or more based on the difference between the inner diameter of the lifter pin and the outer diameter of the shaft portion of the lifter pin or the lid member.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the embodiment shown in FIGS.
As shown in FIG. 1, the processing object mounting mechanism 10 of the present embodiment includes a mounting body (susceptor) 11 disposed in a processing container 20 and a processing object (for example, a wafer) on the susceptor 11. ) A plurality of lifter pins 12 that deliver W, a support body (arm) 13 that supports these lifter pins 12, and a lift drive mechanism (for example, an air cylinder) 14 that drives the arms 13 up and down. The processing container 20 is made of, for example, anodized aluminum, and a hollow gas supply unit 21 that supplies a film-forming gas in a shower shape is integrally formed with the processing container 20 at an upper portion thereof. A film forming gas supply unit 21A is formed on the upper surface of the gas supply unit 21, and a plurality of gas supply holes 21C for supplying the film forming gas in a shower form are formed on the entire surface 21B facing the susceptor 11. It is uniformly distributed.
[0015]
The susceptor 11 is made of a ceramic such as aluminum nitride, and is supported horizontally by a support column 15. A heater 16 is embedded in the susceptor 11 so that the wafer W is heated and maintained up to a predetermined film formation temperature via the heater 16. The lifter pin 12 is made of ceramic such as alumina and is inserted into a through hole 11 A formed in the susceptor 11. The arm 13 is formed in a ring shape from alumina, for example, like the lifter pin 12. The arm 13 is connected to the rod 14A of the air cylinder 14 and is supported horizontally by the rod 14A.
[0016]
By the way, as shown in FIG. 1, the lifter pin 12 is located at the upper end at least in the through hole 11A when positioned at the lower end, and when transferring the wafer W via the air cylinder 14 as shown in FIG. The wafer W protrudes from the through hole 11 A and is supported above the susceptor 11. As shown in FIGS. 1 and 2, the lifter pin 12 is placed in a recessed portion 13 A formed on the upper surface of the arm 13 in accordance with the cross-sectional shape of the base end portion of the lifter pin 12. Therefore, the lifter pin 12 is supported by its own weight in the recessed portion 13 A of the arm 13. The lifter pin 12 can be finely adjusted by the shim S.
[0017]
The recessed portion 13A is formed to have a size capable of absorbing a difference in thermal expansion between the susceptor 11 and the arm 13 at a high temperature during the film forming process. Even if a difference in thermal expansion occurs between the susceptor 11 and the arm 13 during heat treatment, the lifter pin 12 is displaced in the recessed portion 13A. Thus, since the difference in thermal expansion between the susceptor 11 and the arm 13 is absorbed in the recessed portion 13A, in this embodiment, the inner diameter of the through hole 11A of the susceptor 11 is larger than the outer diameter of the lifter pin 12 as in the prior art. It is not necessary to set. Therefore, in the present embodiment, the through hole 11A is merely used as a lifting guide for the lifter pin 12, and therefore, the film forming gas cannot substantially pass through the gap between the through hole 11A and the lifter pin 12, and the lifter pin 12 is in the through hole 11A. The gap is set as narrow as possible.
[0018]
Thus, as a result of examining the relationship between the gap and the passage of the film forming gas, it was found that the gap should be set as follows. That is, as shown in FIG. 3, the inner diameter of the through-hole 11A is D, the outer diameter of the lifter pin 12 is d, and the thickness of the through-hole 11A (in this embodiment, a recess (a counterbore) is formed at the upper end of the through-hole. Therefore, the length from the bottom surface of the recessed portion to the lower surface of the susceptor 11 is set as t, and the relationship between the thickness t of the susceptor 11 and the gap ((D−d) / 2) is represented by the aspect ratio (t / [(D−d) / 2]) and gas passage through the gap is observed, and if the aspect ratio is set to at least 30, more preferably 80 to 100, passage of the film forming gas in the gap is prevented. As a result, deposition of the reaction product of the film forming gas on the back surface of the wafer W is prevented to eliminate the generation source of the particles, and further, the adhesion of the reaction product in the through hole 11A is prevented. Lifter pin in 11A It is possible to prevent the second fixing.
[0019]
As described above, according to the present embodiment, the lifter pin 12 is placed on the arm 13, and the film forming gas substantially passes from the lower surface side of the susceptor 11 to the upper surface side through the gap between the lifter pin 12 and the through hole 11 A. Since the aspect ratio of the size that does not pass, more specifically, the gap and the thickness of the susceptor 11 is set to at least 30, more preferably 80 to 100, the reaction in the back surface of the wafer W or in the through hole 11A during the film forming process. It is possible to prevent product accumulation and eliminate the generation source of particles, and to prevent the lifter pins 12 from sticking in the through holes 11A. Therefore, the lifter pins 12 always operate smoothly during the film forming process, and the wafer W can be transferred smoothly before and after the film forming process. In addition, since the lifter pin 12 is simply mounted on the arm 13, it can be realized at a low cost with almost no change in cost, and the structure of the conventional mounting mechanism can be realized. The placement mechanism 10 of the present embodiment can be obtained with a little effort.
[0020]
Moreover, FIG. 4 is principal part sectional drawing which shows other embodiment of this invention. In this embodiment, the susceptor 11 is configured in accordance with the above embodiment except that the precoat film 17 is applied to the entire surface. The precoat film 17 is a thin film formed by applying, for example, a TiN film in the processing container 20 using a film forming gas prior to the film forming process of the wafer W. By applying the precoat film in this way, the film forming gas hardly passes through the gaps of the through holes 11A and does not reach the back surface of the wafer W. The reason is that during the film forming process on the wafer W, the film forming gas reacts directly with the precoat film 17 in the vicinity of the lower end opening (inlet) of the through hole 11A, and most of the film forming gas in the vicinity of the inlet is consumed. This is presumably because the concentration gradient of the film-forming gas rapidly decreases in the through hole 11A. Accordingly, by setting the aspect ratio as described above and providing the precoat film 17 on the entire surface of the susceptor 11 prior to the film formation process, depending on the film formation process conditions, the reaction product is deposited on the back surface of the wafer W and the lifter pins 12. Can be more reliably prevented.
[0021]
FIGS. 5A and 5B are views showing still another embodiment of the present invention. In this embodiment, a lid member 18 is provided in the through hole 11A, and the lid member 18 is pushed up by the lifter pin 12. And the recessed part 11B is connected with the upper end opening of 11 A of through-holes of the susceptor 11, and the axial center of 11 A of through-holes, and the axial center of the recessed part 11B are mutually corresponded. Others are configured according to the embodiment shown in FIGS.
[0022]
Thus, as shown in FIGS. 5A and 5B, the lid member 18 is composed of a cap portion 18A and a shaft portion 18B connected to the lower surface of the cap portion 18A. The diameter of the cap part 18A is larger than the diameter of the through hole 11A and smaller than the diameter of the recessed part 11B, and the diameter of the shaft part 18B is smaller than the diameter of the through hole 11A. The lower surface of the cap portion 18A and the bottom surface of the recessed portion 11B are formed to be in close contact with each other. As long as the bottom surfaces of the cap portion 18A and the recessed portion 11B are in close contact with each other, any form such as a flat surface or a tapered surface may be used. The shaft portion 18B is formed in a hollow shape, and the tip of the lifter pin 12 is fitted into the hollow portion. Accordingly, in the lid member 18, the shaft portion 18B is fitted into the through hole 11A, and the upper end opening of the through hole 11A is closed by the cap portion 18A. The cap portion 18A is formed to a size that closes the upper end opening of the through hole 11A even if the shaft portion 18B is deviated in the through hole 11A. The gap between the shaft portion 18B and the through hole 11A is preferably the gap of each of the above embodiments in order to prevent the reaction product from adhering in the through hole 11A.
[0023]
The lifter pin 12 includes, for example, a small diameter portion 12A, a large diameter portion 12B, and a connecting portion 12C that connects both of them. The diameter of the small diameter portion 12A is formed so as to fit into the hollow portion of the shaft portion 18B of the lid member 18, and the connecting portion 12C is formed so as to gradually increase from the small diameter portion 12A to the large diameter portion 12B. The tip of the small diameter portion 12A reaches the innermost portion of the shaft portion 18B, but may not be reached when the through hole 11A is sufficiently long, and the lid member 18 is pushed up above the susceptor 11 by the lifter pin 12. I hope you can. Therefore, the shaft portion 18B of the lid member 18 may not be hollow. When the shaft portion 18B is not hollow, the lifter pin 12 can be inserted into the space at the lower end of the through hole 11A without the lower end of the shaft portion 18B reaching the lower end of the through hole 11A. Without it, it ’s good. The lifter pin 12 is also placed in the recessed portion 13A of the arm 13 as in the above embodiments. Therefore, according to this embodiment, since the through hole 11A can be closed by the cap portion 18A of the lid member 18, the same effect as that of each of the above embodiments can be expected. In the case of the present embodiment, it is possible to reliably prevent the formation of deposits on the back surface of the wafer W without providing a precoat film on the susceptor 11.
[0024]
【Example】
Next, the effect of the aspect ratio and the precoat film will be specifically described based on examples.
[0025]
Example 1
In this example, first, a precoat film was provided on the following susceptor. At this time, a susceptor for 200 mm was used, and the following three types of susceptor through holes were used, and the following three types were used as lifter pins. Next, a TiN film was applied to the wafer. In this film formation process, in order to reliably deposit a reaction product of a film forming gas on the back surface of the wafer, a process required for a normal film thickness (20 nm) on the wafer is performed. A TiN film was applied to the wafer under high-pressure process conditions in which the process pressure was sufficiently high in 5 times the time (5 minutes). And after film-forming, the presence or absence of the deposit (pin hole trace) in the through-hole in the back surface of a wafer was observed visually, and the result was shown as the presence or absence of the pin hole trace in the following Table 1. In Table 1, the three types of lifter pins are shown as two types of lifter pins without a cover member as straight pins (1) and (2), and lifter pins with a cover member as pins with a lid.
[Conditions for susceptor]
(1) Thickness of susceptor: 17.0mm
(2) Depression depth: 3.1mm
(3) Through-hole diameter: 4.0 mm
(4) Lifter pin:
Straight pin (1) diameter = 3.6 mm
Straight pin (2) diameter = 3.4 mm
Diameter of shaft part of pin with lid = 3.6mm
[0026]
Example 2
In this example, the same susceptor as in Example 1 was used, and no precoat film was provided on the susceptor. Then, a TiN film was applied to the wafer. In this film formation process, the film formation time was 5 minutes and the process pressure was relatively low. The presence or absence of hole marks was visually observed, and the results are shown in Table 1 below.
[0027]
[Comparative Example 1]
In this comparative example, the same susceptor as in Example 1 was used, and after forming the film under the same high pressure process conditions as in Example 1 without providing a precoat film on the susceptor, the pin holes were the same as in Example 1. The presence or absence of traces was visually observed, and the results are shown in Table 1 below.
[0028]
[Table 1]

[0029]
According to the results shown in Table 1 above, in the case of Example 1 provided with the precoat film, pin hole marks were not confirmed from the first wafer in both the straight pins (1) and (2). That is, there was no pin hole trace in any of the straight pin (1) having an aspect ratio of 70 and the straight pin (2) having an aspect ratio of 46, and no formation of deposits was observed. On the other hand, in the case of Comparative Example 1 in which no precoat film was provided, pin hole traces were confirmed up to the third wafer on the straight pin (1). In Comparative Example 1, there is no data on the straight pin (2). However, the straight pin (2) has a larger gap than the straight pin (1), so it is estimated that pin hole marks are observed.
[0030]
For these reasons, when the pre-coating film is applied to the susceptor, the concentration gas in the through-hole is reacted with the film-forming gas in the pre-coating film near the entrance of the through-hole when the film is formed on the wafer. It is presumed that the value rapidly decreases and does not reach the wafer. On the other hand, when there is no precoat film, there is an incubation time in the film formation reaction on the susceptor during film formation on the wafer, so that the unreacted film formation gas cannot be consumed and the through hole is formed. It is presumed that deposits are formed on the backside of the wafer after passing through. Moreover, in the case of the pin with a cover of Example 1, the pin hole trace was not confirmed though it was natural.
[0031]
On the other hand, when a film is formed on the wafer under low pressure process conditions using a susceptor without a precoat film, the first wafer is obtained even in the case of straight pins (2), as is clear from the results in Table 1 above. No pin hole traces were found on the backside of the wafer. The straight pin (1) has not been confirmed, but since there is no pin hole trace on the straight pin (2) with a large gap, no deposit is generated on the back surface of the wafer even in the case of the straight pin (1). Presumed. In other words, it was found that in the low pressure process, if the straight pin has an aspect ratio of 46, no deposit is generated on the back surface of the wafer.
[0032]
The present invention is not limited to the above embodiments. For example, although the case where the recessed part which mounts a lifter pin was provided on the arm was demonstrated in the said embodiment, this recessed part does not need to be provided. In short, the lifter pin is placed on the support, and the gap between the lifter pin and the through hole may be set to a minimum gap that allows the lifter pin to move up and down.
[0033]
【The invention's effect】
According to the onset bright, realized cheaply always able to operate the lifter pins smoothly, yet simple mechanism when processing the workpiece as well as reliably prevent the formation of deposits on the back surface of the object The mounting mechanism of the to-be-processed object which can be provided can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of an embodiment of a mounting mechanism for an object to be processed according to the present invention.
2 is a partial cross-sectional view showing a relationship between a lifter pin and a wafer when the wafer is delivered on the susceptor shown in FIG. 1;
FIG. 3 is a cross-sectional view for explaining an aspect ratio between a lifter pin and a gap.
4 is an enlarged schematic view showing a state in which a precoat film is provided on the susceptor shown in FIG. 1. FIG.
5A and 5B are enlarged cross-sectional views showing a main part of another embodiment of the mounting mechanism for the object to be processed according to the present invention, in which FIG. It is a figure which shows the state mounted on the susceptor.
FIG. 6 is a conceptual diagram showing a cross-sectional structure of a conventional film forming apparatus.
7 is a cross-sectional view of a main part showing the relationship between the susceptor and the lifter pins shown in FIG. 1, in which (a) shows a room temperature state, and (b) shows a film forming process. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 To-be-processed mounting mechanism 11 Susceptor 11A Through-hole 11B Recessed part 12 Lifter pin 13 Arm (support body)
13A Concave portion 14 Elevating drive mechanism 18 Lid member 18A Cap portion 18B Shaft portion

Claims

In a plurality of through holes formed in the mounting body, a mounting body on which a target object to be deposited with the film forming gas supplied in the processing container is formed. A plurality of lifter pins that are respectively inserted and deliver the object to be processed on the mounting body, a support body that supports the lifter pins, and a lifting mechanism that lifts and lowers the lifter pins through the support body. In the mounting mechanism, the lifter pin is mounted on the support, and the film forming gas substantially passes from the lower surface side to the upper surface side of the mounting body through the gap between the lifter pin and the through hole. A mounting mechanism for an object to be processed, characterized in that a recess is provided on the support, which is set as a gap not to be closed and in which a base end of the lifter pin is loosely fitted .

In a plurality of through holes formed in the mounting body, a mounting body on which a target object to be deposited with the film forming gas supplied in the processing container is formed. A plurality of lifter pins that are respectively inserted and deliver the object to be processed on the mounting body, a support body that supports the lifter pins, and a lifting mechanism that lifts and lowers the lifter pins through the support body. In the mounting mechanism provided, the concave portion of the above-described mounting body is connected to the upper end of each through-hole, and a lid member that closes the through-hole by inserting a shaft portion into each through-hole is provided for each of the concave portions. And the upper end of each lifter pin is inserted into the through hole, the lifter pin is placed on the support, and a recess in which the base end of the lifter pin is loosely fitted is provided on the support. the processing being characterized in that provided in the upper The body of the mounting mechanism.

The mounting mechanism for the object to be processed according to claim 1 or 2 , wherein a height from a base end of the lifter pin is adjustable.

The mounting mechanism for the object to be processed according to any one of claims 1 to 3, wherein a precoat film is provided on the mounting body.

The aspect ratio based on the axial length of the through hole and the difference between the inner diameter of the through hole and the outer diameter of the shaft portion of the lifter pin or the lid member is set to at least 30 or more. The mounting mechanism of the to-be-processed object of any one of Claim 4 .