JP3816426B2 - Process processing equipment - Google Patents

Description

なお、Ｉ(ｘ，ｙ)は、例えば図２１に示す検出像１８５の０次回折光１８４の強度を表す。
【００６７】
この方法は、回転位置θ₁又はθ₂が存在する範囲（θ₁−δ₀＜θ＜θ₁＋δ₀又はθ₂−δ₀＜θ＜θ₂＋δ₀）を予め知っている必要があり、存在範囲をより正確に予測できたときに検出精度が向上する。従って、事前にオリフラ合わせ等により各ワーク（ウエハ）の向き、つまりチップ配列方向θをある範囲にそろえておく必要がある。また、１次以上の回折光が存在しない場合は、加算範囲を０度から９０度にしても理論上は完全な値が算出できる。従って、１次以上の回折光強度は小さい方が望ましい。演算時間が問題にならなければ、２次元のＨｏｕｇｈ変換を用いれば良いのは言うまでもない。
【００６８】
また、以上の式ではθを算出してヒストグラムを求めたが、演算時間の短縮と言う観点からは、ｔａｎθ、ｓｉｎθあるいはｃｏｓθを算出してヒストグラムを求めても良い。微細な光軸のずれがあった場合、θは誤差を持った状態で算出される可能性がある。この回折光を用いた方式の場合、微細な光軸のずれは具体的には、ヒストグラムのピークの山割れ現象（図２７（ｃ）に示す。）となる。これは、図２７（ｂ）に示すように、回折パターン１８４の場合、真の直線の方向θに対して芯ずれの際に算出される誤差を持った角度が、＋側と−側に存在するために生じる。従って、上記に示したように、重心を算出する場合、光軸のずれはキャンセルされることになる。この意味でも、（３）式に基づいて、重心を求める方法は高精度算出が期待できる。
【００６９】
以上の１次元のＨｏｕｇｈ変換を用いた方法は、光軸中心が、検出した画像上に無い場合も適用可能である。具体的には、画像の外に存在する光軸中心を画像と同一の座標系で表せばよい。
この回折光を用いる方法では、光軸中心の検出信号出力が極端に大きい場合が多く画像上の光軸中心の周囲の広い範囲に渡って検出器の出力が飽和してしまうことが多い。そこで、光軸中心の適当な範囲をマスクしてしまい、θの算出に使わない方が検出精度が向上する場合が多い。このマスクは、光学系上に設置された遮光板、あるいは、検出した信号の中心部のデータを用いないと言ったソフト上のｓマスクであっても良い。
実際には、図２１の検出像１８５に示すように、±１次あるいは±２次の回折パターン１９２が形成、検出される。ところが、通常は、これらのパターン１９２は、０次回折光１８４より微弱であるため、以下に示す方法で無視できる。第一に、しきい値を用いて２値化する方法、第二に多値のデータを用いる方法である。検出器が２次元の場合を説明したが、１次元の検出器を用いても以下のように、回転検出系が実現できる。
【００７０】
即ち、図２３に示す処理装置でウエハ回転ずれを補正することができる。この処理装置（補正装置）は、回転検出光学系１１０ｅ（検出器１７５）、回転検出算出系１８６、隣接チップ対応点ベクトル算出系（ａ、ａ’の座標関係）１８７、画像データを記憶するメモリ１８９、比較手段１９０から構成される。回転検出算出系１８６では、上記説明した方法によりチップ配列の方向θが算出される。このθと、設計データから入力されるチップピッチｐのデータより、隣接チップ対応ベクトルが算出される。チップ比較手段１９０では、メモリ１８９に蓄積されたメモリ情報からリニアイメージセンサ４０の長手方向に対する隣接チップ対応ベクトルにより対応点（図２４に示すａとａ’、ｂとｂ’）が取り出され、信号出力が比較されて、不一致による異物信号１８８が検出される。ここで、視野は、チップピッチの２倍より大きい必要がある。また、ワーク（ウエハ）の許容傾き（異物検査を実施する上で許容できるワークの傾きの範囲）をθとすると、メモリ１８９に記憶するメモリの範囲ｌは、リニアイメージセンサ４０の視野サイズにｓｉｎθを乗じた長さの範囲を記録できる容量が必要になる。
【００７１】
次にワーク走査方向比較方式での回転補正について図２４（ｂ）に基づいて説明する。即ち、比較する隣接チップが、図２４（ａ）に示すように、リニアイメージセンサ４０の長手方向の場合について説明してきたが、比較対象チップは、リニアイメージセンサ４０の長手方向である必要はなく、以下に説明するように、リニアイメージセンサ４０の長手方向に直角な方向、すなわち、ワークの走査方向であっても良い。上記のリニアイメージセンサ４０の長手方向の比較と同様に、リニアイメージセンサ４０の長手方向に直角な方向に対する隣接チップ対応ベクトルを算出することにより隣接チップの対応点を求めることができる。メモリのサイズ（メモリ範囲ｌ）についても同様の演算により算出できる。
【００７２】
この場合、検出視野がチップサイズに対して十分に大きな値を持っていない場合であってもチップ比較が実現できる反面、ハンドリング機構等によるワークの送り精度を高くして、走査方向に存在する隣接チップの対応点を正確に知る必要がある。また、この走査方向比較では、θが０度に近い場合、照明のムラ、検出レンズのムラなどの影響がなくなるという効果がある。
【００７３】
次に回転合わせ機構による回転補正について図２５及び図２６を用いて説明する。即ち、前記メモリを用いた処理装置による回転補正に対して、回転検出算出系１８６で算出されるチップ配列の方向θ（図２６に示す。）に基づいて光学系３６全体（照明系３１及び回転検出光学系１１０も一緒にしても良い。）またはワーク（ウエハ）を回転させることによって、隣接チップの対応点の算出を簡便にすることができる。そしてチップ比較手段１９１において、メモリ１８９に蓄積されたメモリ情報から対応点が取り出され、信号出力が比較されて不一致による異物信号１８８が検出される。さらにこの方法の効果として、ワーク（ウエハ）を走査する機構の精度（送り速度のムラ、光軸方向の振動、走査方向検出器方向の振動など）が悪い場合でも対応できる点がある。また、このように回転合わせ機構を用いることにより、走査方向とチップ配列方向を垂直にする必用がなくなる。また、空間フィルター３９を用いる場合、空間フィルター３９の角度がチップ配列に対して正確に合うため、空間フィルター３９の効果を最大限に引き出すことができる。
【００７４】
次に０次カット空間フィルター方式＋チップ比較について説明する。即ち、チップ比較方式を用いる場合、必ずしもｎ次の回折光を遮光する空間フィルター３９を用いる必要のない場合がある。特に、ウエハ４上に形成されたチップパターンの最小セルサイズが小さくなり、その１次以上の回折光が検出レンズ３７に入らない場合、０次光だけを遮光すればよいことがある。この場合、空間フィルター３９を用いる際に必要なウエハ４のそりに対する対応、ウエハ４の傾きに対する対応が不必要になるという利点がある。ウエハ上のチップ配列方向が図３０に示すように、θの時の回折光及び検出レンズの開口の様子を図２８、図２９に示す。図２８は照明の入射角度α、検出レンズ３７の見込み角γとし、ある球面２８２を想定し、この球面２８２と照明の交点２８３、検出レンズ３７の見込み角との交線２８４を図２９に示す。なお、２８３は球面２８２上の入射点、２８５は球面２８２上の出射点である。ここで、検出レンズ３７に０次回折光が入射しないようにウエハ４をθ方向に回転する事によって、ウエハ４上の主なパターンの情報を消去することができる。これにより、ウエハ４内のパターン上に付着した異物あるいは欠陥を強調して検出することができる。このようにして検出した後に、上記のチップ比較を実施すれば、上記の異物や欠陥を検出できる。検出光学系３８がパターンを逃げる条件の式は次に示す（４）式で得られるｘ０まで相対的にウエハ４を回転する。つまり、ｘ０−θだけ相対的にウエハ４を回転する。
ｓｉｎα・ｓｉｎ（ｘ０）＞ｓｉｎγ （４）
この際の回転角ｘ０の最大値ｘ０（ｍａｘ）は、上記の（４）式より次の（５）式の関係で求められる。
ｓｉｎ（ｘ０（ｍａｘ））＝ｓｉｎγ／ｓｉｎα （５）
即ち、ウエハ４と検出器４０を含めた検出光学系３６との間の相対的な回転ストロークは、上記のｘ０（ｍａｘ）が実現できるように選定されれば十分である。具体的には、検出光学系３６の対物レンズ３７の開口数（ＮＡ＝ｓｉｎγ）が０．１程度（焦点距離ｆ＝約７０ｍｍ（図１０（ｂ）に示すように搬送室１０４の外側から透明な窓１０６を通してワーク（ウエハ）４上の異物を検出するためには焦点距離ｆとして約５０ｍｍ以上は必要となるためである。）、焦点深度が約±６０μｍ（自動焦点合わせをしないでワーク（ウエハ）４上の異物を検出するために焦点深度として±４０μｍ〜±３０μｍ程度が必要となる。）で、αが６０度の場合、ｘ０（ｍａｘ）は約６．６度となり、検出光学系３６の対物レンズ３７の開口数（ＮＡ＝ｓｉｎγ）が０．０８程度（焦点距離ｆ＝約９０ｍｍ、焦点深度が約±６０μｍ）で、αが８５度の場合、ｘ０（ｍａｘ）は約４．６度となり、ｘ０（ｍａｘ）、即ち相対的な回転ストロークとして５度から１０度程度の回転許容範囲が実現できれば十分である。ワーク（ウエハ）４がθとして、θ＞ｘ０（ｍａｘ）の条件で搬送されてくるのならば、ワーク（ウエハ）４または検出光学系３６を回転させることが必要でないことは明らかである。
【００７５】
以上の方法は、検出光学系３６の中に０次カットフィルター３９を設置する必要がなくなるため、検出光学系３６の結像性能を落とさずに済むと言う効果がある。
【００７６】
ここでは、上記の０次回折光が遮光できれば良いわけであるから、ウエハ４の回転角度θが０度になるように設定されても良い。この場合、図３及び図３１に示す０次カットフィルター３９が必要になる。この場合の０次カットフィルター３９は幅を広めに、具体的には、０次回折光が十分に遮光できるように実験的に求められるものである。この場合、前述したように、ウエハ４の回転を検出し、回転補正を実施してチップ配列ベクトルを算出してチップ比較を実現する方法と、ウエハの回転検出はせずにチップ比較をしない方法が考えられる。しかしながら、チップ比較を実施する方法が、実施しない方法に対して検出感度等が低くなる。特に、ウエハ４上に形成されたパターンにおいては、角部の丸みのように様々な方向成分を有して０次カットフィルター３９で全てを取り除くことができない。従って、チップ比較をすることによって０次カットフィルター３９で消去できないものも除去することができる。
【００７７】
［第９実施例］
次に検査ユニット（検出ヘッド１ａ、ハンドリング機構５等から構成）の設置に関して説明する。即ち、以上説明した検査ユニットを所定の仕様でプロセス装置（図１、図９及び図１０に示す。）、ウエハの搬送系５（図１、図９及び図１０に示す。）、ウエハストッカ部１３１（図１３に示す。）等に設置すればよい。検査時には、この検査ユニット（検出ヘッド１ａ）を構成する検出光学系３６の焦点深度の範囲内で、ワーク（ウエハ）４の検査面を通過させる。即ち、この際、ワーク（ウエハ）４の検査面を、この焦点深度の範囲内で通過させれば良い。また、ワーク（ウエハ）４を載置するステージまたは搬送するアーム等のハンドリング機構によっては、ウエハのそりが吸収できない場合があり、このような場合、後述する自動焦点や自動傾き合わせが必要になる。この場合であっても、ウエハのそりの曲率は問題になるレベルではない。
【００７８】
次にワーク（ウエハ）４を搬送するためのハンドリング機構５におけるアーム５ａについて図３３に基づいて説明する。前記したようにワーク（ウエハ）４の検査面を、検査ユニット（検出ヘッド）１ａの検出光学系３６の焦点深度の範囲内にする必要がある。そのため、ワーク（ウエハ）４を平坦なステージまたはアームに吸着する必要がある。真空中においては、真空吸着ができないため静電吸着タイプの吸着方式が望ましい。たとえば、静電吸着タイプの搬送アームの例を図３３（ａ）、（ｂ）に示す。この静電吸着アーム３３１（５ａ）の電気回路３３３（図３３（ｂ）に示す。）の構成の例を示している。ウエハ４のそりは±１０μｍ程度におさえる必要がある。
【００７９】
図３３（ｂ）に静電チャック３３２の断面を示す。１対の電極３３３を並べたものであり、２極に高電圧３３５をかける。吸着開始時にスイッチング信号３３７に基づいてスイッチング回路３３６を制御して高電圧３３５からの電圧をかけ、吸着除去時にスイッチング信号３３７に基づいてスイッチング回路３３６を制御して２局を短絡する。このステージは、あくまで、ワーク（ウエハ）４の搬送用として、前述した搬送ロボット（ハンドリング機構）５のアーム５ａとして使用されるものであり、かつ、ワーク（ウエハ）４のそりをなくすものである。従って、ローダ又はアンローダ（ウエハカセット）８ａ、８ｂからワーク（ウエハ）４を引き抜くに十分な薄さを有し、ワーク（ウエハ）４のそりを矯正するに十分な厚さを有するものである。具体的には、厚さ２ｍｍ〜６ｍｍ程度のセラミックがよい。また、大きさも、ワーク（ウエハ）４のそりを矯正するに十分なものでなければならない。具体的には、ワーク（ウエハ）４の半径の６割から１０割の半径を持つ形状が良い。もちろん、形状は円盤状である必要はなく、矩形、三角形等の他の形状であってかまわない。
また図３３（ｃ）、（ｄ）に、大気中の搬送アーム３２１の断面を示す。この搬送アーム３２１には、真空源（図示せず。）に接続された排気通路３２４に連通した穴３２３につながった真空吸着溝３２２が設けられ、ワーク（ウエハ）４を真空吸着できるように構成されている。このように大気中では、搬送アーム５ａにおいて図３３（ｃ）、（ｄ）に３２１で示す真空吸着式が使用できるので、上記真空吸着式が望ましい。もちろん前述したように静電吸着であっても良い。また、そのほかの形状、厚さ、材質等は、前述した静電吸着タイプのものと基本的には同一である。
このような、搬送アーム５ａは、異物検査のためだけでなく、ワーク（ウエハ）４のそりが問題になるその他の用途にも用いられるべきものであることは言うまでもない。即ち、ハンドリング機構（搬送ロボット）５の搬送アーム５ａは、プロセス装置（図１、図９及び図１０に示す。）、ウエハの搬送系５（図１、図９及び図１０に示す。）、ウエハストッカ部１３１（図１３に示す。）等に設置され、ワーク（ウエハ）４を搬送するためのものである。
【００８０】
次にワーク（ウエハ）のそり対応の装置について図３４〜図３８を参照して説明する。本発明による異物検査装置１は、ワーク（ウエハ）４にそりがあった場合、２つの点で問題になる。一つは、そりによる検出光学系（対物レンズ３７）３６の焦点位置の変動である。たとえば、図３４（ａ）に示すように、８インチウエハ４の中央が周囲に対して４００μｍ膨らんだような形状のそりがある場合、視野３４１の３５ｍｍの範囲では光軸方向に最大約１４０μｍの変動となる。２つめは、このそりによるウエハ４の表面の傾きにより、ウエハパターンのフーリエ変換像の位置が、予め設置されている空間フィルター３９と位置ずれを起こしてしまい空間フィルタリング効果が損なわれることである。上記の程度のそりの場合、つまり（Δδ＝１４０μｍ／３５ｍｍ）の傾きの場合、図３６に示すようにフーリエ変換面３６１での位置ずれは、（１４０μｍ／３５ｍｍ）・（ｆ＝７０ｍｍ）となり、２８０μｍの位置ずれとなる。なお、ｆは、検出光学系（対物レンズ３７）３６の焦点距離である。
【００８１】
これら２つの問題を解決するため以下の方法が必要となる。
上記説明したように、ウエハ全体では、複雑な形状をしたそりも、３５ｍｍの視野３４１内では、ほぼ平面と考えられる。従って、図３４（ａ）に示すように、この視野３４１内の中央部での法線方向と光軸を合わせるような調整機構を設ければよい。即ち、図３４（ｂ）、図３５〜図３８にウエハ４のそり対応の装置を示す。この装置は、そりの検出部３４５ａ，３４５ｂとそりへの合わせ機構部３８１とから構成される。
【００８２】
即ち、この装置（そりの検出部３４５ａ，３４５ｂとそりへの合わせ機構部３８１とから構成される。）は、光源３１（図３４（ｂ）に示す。）又は光源３４９（図３５（ｂ）に示す。）、ミラー３４８を有する結像光学系３４６（図３４（ｂ）に示す。）又は結像光学系３５０（図３５（ｂ）に示す。）、２分割検出器（１次元又は２次元のイメージセンサでも良い。）３４７、２分割検出器３４７からの信号ａ，ｂについて処理する信号処理系３５０、図３８に示すように該信号処理系３５０から得られるワーク（ウエハ）の表面の傾きΔδを示す信号３５１を受信して駆動部を制御するコントローラ３８２、該コントローラ３８２からの駆動信号によって駆動される駆動部３８３から構成される。光源３１、３４９から射出した光は、結像光学系３４６、３５０により２分割検出器３５２上に結像される。信号処理系３５０では、この２分割検出器３５２における受光部３５２ａからの信号ａと受光部３５２ｂからの信号ｂとにより、例えば、コントラスト（ａ−ｂ）／（ａ＋ｂ）等の算出処理を施し、この値（ａ−ｂ）／（ａ＋ｂ）（図３７に示す。）が、０（合傾範囲内）になるように検出光学系３６全体を、そりへの合わせ機構部３８１により光軸とリニア検出器４０を含む平面内でΔδ方向に回転させ、そりの法線方向と光軸が重なるように調整する。この調整は、検出光学系３６とワーク（ウエハ）４が相対的に走査される間、自動的、独立に調整され続ける。図３５（ａ）に、２分割検出器３５２においてワーク（ウエハ）４の傾きに応じて検出する状態を示す。即ち、ワーク（ウエハ）４の表面が傾いていない場合、２分割検出器３５２において中心線３５６に位置する実線で示す光束３５４を受光し、ワーク（ウエハ）４の表面がΔδ方向に傾いている場合、２分割検出器３５２において中心線３５６から偏位した点線で示す光束３５５を受光することになる。
また、上記の信号処理系３５０ではコントラストを算出したが、差ａ−ｂ、あるいは比ａ／ｂ等の演算であっても良い。また、この際の回転中心は、光軸とワーク（ウエハ）４との交点あるいはその近傍であることが望ましい。この場合、ワーク（ウエハ）４内の視野が、走査方向に垂直な方向で変動することがないからである。
【００８３】
そりへの合わせ機構部３８１の構造は、ボールベアリングを用いた構造、板バネを用いた構造、コイルバネを用いた構造、リンク構造などであってかまわないが、図３８に、コイルバネ３８８を用いた構造を一例として示す。この場合、傾き合わせの回転中心はコイルバネの中心付近になり、光軸とワーク（ウエハ）４との交点からやや離れることになるが、十分交点に近いと考えられる。なぜなら、この回転中心と上記交点との距離をｄとすると、上記の例の傾きが存在した場合の光軸傾きの調整結果として、視野の検出器方向のずれは、（１４０μｍ／３５ｍｍ）・（ｄ＝たとえば３５ｍｍ）＝１４０μｍとなり、問題になるほど大きな値ではない。さらにリンク構造等を用いこの回転中心を上記の交点に近づけることができる。この際のΔδ方向の駆動系は、圧電素子を用いても、図３８に示したように、パルスモータ３８３の出力軸に取付けられたカム機構３８４を用いても良い。３８７は、枠状をした検出ヘッド１ａの基台（ベース）である。パルスモータ３８３及びパルスモータ３８５は、基台（ベース）３８７に取付けられている。３８９は、照明光学系３１及び検出光学系３６を取り付けた板部材である。従って、照明光学系３１及び検出光学系３６は、パルスモータ３８３を回転駆動することによってカム機構３８４によりコイルバネ３８８を中心にしてΔδ方向に傾斜して補正することになる。またパルスモータ３８５を回転駆動することによってカム機構３８６によりＺ方向にΔｚ変位して補正することになる。
【００８４】
次に自動焦点検出系について図３８〜図４４を参照して説明する。即ち、ワーク（ウエハ）４のそりは、ワーク（ウエハ）４の傾きとなると同時に、特にワーク（ウエハ）４の周辺部で、焦点位置からのずれとなって現れる。従って、この焦点位置の検出と調整機構が必要になる。図３９に自動焦点検出系の一実施例を示す。自動焦点検出系は、光源４０５、スリット４０６、結像光学系４０４、スリット４０１ａ，４０１ｂ、検出器４０２ａ，４０２ｂ、信号処理系４０３、駆動系３８５，３８６（図３８に示す。）より構成される。光源４０５としては、より輝度の高いものが望ましく、結像光学系４０４を通して焦点位置測定対象物（ワーク（ウエハ）４）上にスリット４０６の像が結像される。さらに同一の結像光学系４０４により、ワーク（ウエハ）４上に結像したスリット像が検出器４０２ａ，４０２ｂの前に設置されたスリット４０１ａ，４０１ｂ上に結像される。ここで、光源４０５の後のスリット４０６と検出器４０２ａ，４０２ｂの前のスリット４０１ａ，４０１ｂは完全に共役な位置にあるのが望ましい。即ち、これらのスリット４０６、４０１ａ，４０１ｂの形状は同一であり、結像光学系４０４の横倍率分だけ大きさが異なっている必要がある。ここで、これら検出器４０２ａ，４０２ｂの各々の前に設置されたスリット４０１ａ，４０１ｂは、焦点が合う位置から光軸方向にそれぞれ後方にΔＺ₁、前方にΔＺ₂ずらされて設置される。４０１は、結像光学系４０４の開口数（ＮＡ）を決定する視野絞り（フィルタ）である。４０７、４０８はハーフミラーである。
【００８５】
以下、焦点位置検出の作用について説明する。
図４１にデルタ関数（スリットの短軸方向）Ｐ（ｕ）（図４１（ｃ）に示す。）、焦点ぼけ関数（ベッセル関数）Ｄ（ｕ）（図４１（ｂ）に示す。）及び光学的伝達関数（円錐状の関数）Ｍ（ｕ）（図４１（ａ）に示す。）のフーリエ変換、つまりフーリエ変換領域での形状を示す。検出信号は、これらの関数の積（Ｍ（ｕ）・Ｄ（ｕ）・Ｐ（ｕ））（図４１（ｄ）に示す。）を取り、さらにフーリエ変換して算出された形となる。図４２（ａ）にこの形状を示す。焦点ぼけが生じたとき、像の大きさが広がり、検出信号のレベルが下がる現象を示す。従って、同じ大きさの開口（スリット）４０１ａ，４０１ｂを配置し、この開口４０１ａ，４０１ｂを通過してきた信号（図４２（ｂ）に示す。）を各検出器４０２ａ，４０２ｂにおいて測定する。ここで、２つの検出器４０２ａ，４０２ｂの位置をそれぞれ前後に配置しておけば、焦点ずれが生じたとき、図４３（ａ）に示すように一方が増加し、一方が減少する。そこで、信号処理系４０３において、この２つの信号のコントラスト（ａ−ｂ）／（ａ＋ｂ）を算出すれば、図４３（ｂ）に示す信号となり、これが０点（許容範囲内）を通過するのが焦点位置になる。４０５は光源、４０６は２次光源を形成するスリットである。
【００８６】
この発明を実施する上で考慮すべきことは、２つの検出器４０２ａ，４０２ｂをどれだけ離すか、結像光学系４０４の開口数（ＮＡ）をいくつにすべきかの２点である。これは、本発明の自動焦点系の測定レンジ及び測定精度と密接に関わる。具体的には、一方の検出器からの出力信号のピーク位置とこの出力信号がピーク位置から１／１００程度に下がる位置までが焦点深度となり、２つの検出器４０２ａ，４０２ｂの間の距離はこの焦点距離分だけ離すのがよい。レンズ４０４の開口数はこの焦点深度を決めることになるため、測定レンジを広げたい場合は、開口数を小さく、測定精度を向上したい場合は、開口数を大きくする。レンジと精度の両立は難しいため、以下に示すような工夫がいる。
【００８７】
レンズ４０４の瞳上に図４０に示すような長方形状（あるいは楕円、長円等）のマスク４１０ａを載置し、ｘ方向、ｙ方向で開口数を変えるようにする。さらに２次光源のスリット４０６ａを図に示すような２つの直行するスリットを設け、それぞれを２組の検出器４０２ａ，４０２ｂと検出器４０２ａ’，４０２ｂ’で別々に検出する。この際、開口数の違いによりそれぞれのスリットの焦点深度が異なるため、検出器４０２ａ，４０２ｂと検出器４０２ａ’，４０２ｂ’との間の距離はそれぞれの組で異なるように設定する。具体的には、長方形のマスク４１０ａの短い方向では、開口数が小さくなるため焦点深度が大きくなり検出器間の距離も離す必要が有る。図４４（ａ）には、検出器４０２ａから出力される信号ａ、検出器４０２ｂから出力される信号ｂ、検出器４０２ａ’から出力される信号ａ’、検出器４０２ｂ’から出力される信号ｂ’を示す。また図４４（ｂ）には、信号処理系４０３で処理された（ａ−ｂ）／（ａ＋ｂ）と、（ａ’−ｂ’）／（ａ’＋ｂ’）との信号を示す。この２つのレンジの焦点検出系を組み合わせることにより、つまり、粗精度高レンジの系で高精度低レンジの測定レンジまで調整することができるので、総合的には、高精度、高レンジの焦点検出系が実現できる。ここではスリットを用いているが、複数のスリット任意な位置に配列したものであっても、ある幅を持ったリング形状のスリットであっても、あるいはこれらの組み合わせたものであってもかまわない。
【００８８】
ここでスリットの変わりにピンホールでもかまわないが、スリットを用いることによりスリットの長手方向の積分効果が現れる。ワーク（ウエハ）４上に回路パターン等のパターンが形成されており、更に２つの検出器４０２ａ，４０２ｂ及び４０２ａ’，４０２ｂ’のスリットへの結像位置が多少のズレがある場合、２つの検出器４０２ａ，４０２ｂ及び４０２ａ’，４０２ｂ’の信号は、焦点変動に対して同一形状の変動をしなくなる。上記の積分効果によってこのようなスリットの位置ずれがある場合であってもその影響を軽減できる効果がある。
本実施例の自動焦点検出系では、ワーク（ウエハ）４に傾きがあっても、無視できるという効果を有する。また、縞パターン投影するタイプより信号処理系が単純であると言う効果がある。
また、本実施例では、ワーク（ウエハ）４上に結像するいわゆる２次光源としてスリットを用いているが、スリットを用いずに点光源を用いても、あるいは、検出器側だけにスリット（あるいはピンホール）を用いても良い。
以上説明した実施例によれば、縞パターン投影等の煩雑な信号処理をせずに、焦点位置が自動的に算出される。
自動焦点検出部は、ここに示したような光を用いるものでも、あるいは、静電容量を用いるものでも、また気圧変化を検出するものでも良い。
【００８９】
図４５及び図４６にワーク（ウエハ）のそりの対応と自動焦点合わせとの両方を行わせる実施例を示す。即ち、照明光学系３１でワーク（ウエハ）４の表面に集束照明された線状の光束４１を結像光学系４５１で２分割検出器（１次元又は２次元のイメージセンサでも良い。）４５２上に結像させ、４５２ａと４５２ｂとの境界である中心に線状の光束４１が結像されるのを検出することによって検出光学系３６の自動焦点合わせを行うことができる。即ち、例えば、受光部４５２ａからの信号ａと受光部４５２ｂからの信号ｂとに対して（ａ−ｂ）／（ａ＋ｂ）なる演算を信号処理系４０３で施してその値が０になるように、例えば図３８に示すように検出光学系３６をＺ方向に微動させることによってワーク（ウエハ）４の表面を自動焦点合わせを行うことができる。同時に照明光学系３１でワーク（ウエハ）４の表面に集束照明された線状の光束４１を結像光学系３４６で２分割検出器（１次元又は２次元のイメージセンサでも良い。）３５２上に結像させ、３５２ａと３５２ｂとの境界である中心に線状の光束４１が結像されるのを検出することによって検出光学系３６をワーク（ウエハ）４の表面の傾きに合わせることができる。即ち、例えば、受光部３５２ａからの信号ａと受光部３５２ｂからの信号ｂとによって（ａ−ｂ）／（ａ＋ｂ）なる演算を信号処理系３５０で施してその値が０になるように、例えば図３８に示すように検出光学系３６をΔδ方向に微動させることによってワーク（ウエハ）４の表面の傾きに合わせることができる。即ち、図４５及び図４６に傾き補正、自動焦点の実施例を示す。本実施例は、検出器３５２、４５２は、前述したような、２分割素子を用いたものであるが、検査のための照明光学系３１の光束を用いるものである。図示するように、傾き検出は、ウエハ上の検査位置（照明点）のフーリエ変換の位置にｙ方向で２分割されるように２分割検出器３５２を置く。また、自動焦点は、ウエハ上の検査位置（照明点）の結像の位置にｘ方向で２分割されるように２分割検出器４５２を置く。このような構成により新たな照明を必要としない効果がある。
【００９０】
［第１０実施例］
次に検査ユニット（検出ヘッド）１ａ，１ａ’を、プロセス装置（ウエハ４上にＡｌ等の金属薄膜を形成するスパッタ装置、ウエハ４上に絶縁薄膜を形成するＣＶＤ装置、エッチングを施すエッチング装置等）（図１、図９及び図１０に示す。）、ウエハの搬送系５（図１、図９及び図１０に示す。）、ウエハストッカ部１３１（図１３に示す。）等に設置する仕方について、図４７及び図４８を用いて説明する。
【００９１】
即ち、本発明において、２チップ比較検査をする際、図２２〜図２４に示すように回転補正オペレータ１８７が必要になるが、この回転補正オペレータをソフト処理（電気的処理）で行うことができる。しかし、空間フィルタ（０次カットフィルタ）３９を用いる場合（図３及び図３１に示す。）においては、空間フィルタ３９の方向とウエハ上に形成されたチップ格子の向きθとを合わせる必要があり、また空間フィルタ（０次カットフィルタ）３９を用いない場合（図２９に示す。）においても、ウエハ上に形成されたチップ格子の向きθをｘ０（ｍａｘ）より大きくする必要がある。一方、プロセス装置に搬入されてハンドリング機構５の搬送アーム５ａで搬送される場合、通常ウエハ４はオリフラ合わせされており、±１０度以下の回転ずれが生じた状態である。従って、この回転ずれをウエハ側か、あるいは検査ユニット（検出ヘッド）１ａ，１ａ’側のどちらかで補正することが必要となる。
【００９２】
ウエハ４側で行おうとすると、ハンドリング機構（ロボット機構）５において、搬送アーム５ａの先端（ウエハ４の中心）を中心にして微回転させる必要があり、搬送アーム５ａの駆動制御が複雑となる。また搬送アーム５ａの先端に微動回転ステージを設けて、この微動回転ステージを微回転駆動させて回転ずれを補正することができるが、搬送アーム５ａの機構が複雑になってしまう。また搬送アーム５ａとは、別に回転ステージを設けることも考えられるが、この回転ステージを設けるためのスペースが必要となる。このように、プロセス処理装置内に設置されたハンドリング機構（ロボット機構）５として特殊なものにしなければならなくなり、共通性が失われることになる。
【００９３】
そこで、検査ユニット（検出ヘッド）１ａ，１ａ’側で回転ずれ補正を行うと上記課題は解決することができる。しかし、検査ユニット（検出ヘッド）１ａ，１ａ’の機構は、多少複雑になる。図４７には、検査ユニット（検出ヘッド）１ａ，１ａ’側で回転ずれ補正を行う実施例を示す。
図４７（ａ）に示す実施例では、例えば３チャンネル（照明光学系３１と検出光学系３６との組を３組）の検査ユニット（検出ヘッド）１ａ，１ａ’をアーム部材４７１上に設置し、該アーム部材の中心４７３を回転中心にしてアーム部材４７１全体を、円弧状ガイド（円弧状レール）４７２に沿って摺動自在に片持ち支持して回転できるように構成している。なお、４７４は、円弧状ガイド（円弧状レール）４７２上に固定された歯車である。４７５はアーム部材４７１上に設けられたモータであり、出力軸に取り付けられた歯車が、上記歯車４７４と噛み合っている。そしてモータ４７５を回転駆動させることによって、アーム部材４７１は４７３を中心にして回転し、±１０度以下の回転ずれを補正することができる。
【００９４】
図４７（ｂ）に示す実施例では、例えば３チャンネル（照明光学系３１と検出光学系３６との組を３組）の検査ユニット（検出ヘッド）１ａ，１ａ’をアーム部材４７１上に設置し、該アーム部材の中心４７３を回転中心にしてアーム部材４７１全体を、円弧状ガイド（円弧状レール）４７２に沿って摺動自在に片持ち支持して回転できるように構成している。なお、４７６は、アーム部材４７１に固定された歯車である。４７７は円弧状ガイド（円弧状レール）４７２上に設けられたモータであり、出力軸に取り付けられた歯車が、上記歯車４７６と噛み合っている。そしてモータ４７７を回転駆動させることによって、アーム部材４７１は４７３を中心にして回転し、±１０度以下の回転ずれを補正することができる。
【００９５】
上記実施例では、回転のガイド４７２として、中心が上記のアーム部材４７１の中心４７３になるような円弧状のものを用いている。しかしながら、このガイドは、このような円弧状のものである必要はなく直線状のガイドとリンク機構を用いても良い。
図４７（ｃ）に示す実施例では、例えば３チャンネル（照明光学系３１と検出光学系３６との組を３組）の検査ユニット（検出ヘッド）１ａ，１ａ’を板状部材４７９上に設置し、該板状部材４７９を、基台（ベース）に片持ちで固定されたアーム４７８の先端において軸心４７３に回転自在に支持して構成している。そしてアーム４７８の先端の軸心４７３にモータ４８０を設け、該モータ４８０の出力軸を板状部材４７９に直結し、モータ４８０を回転駆動させることによって、板状部材４７９は軸心４７３を中心にして回転し、±１０度以下の回転ずれを補正することができる。
このように、検査ユニット（検出ヘッド）１ａ，１ａ’をアーム部材４７１、または固定されたアーム４７８により片持ち支持するように構成したことにより、検査ユニット（検出ヘッド）１ａ，１ａ’を、４７３を中心にして、±１０度以下の回転ずれを補正する機構として、必要スペースを最小にすることができる。
【００９６】
図４８には、回転ずれを補正する機構のない検査ユニット（検出ヘッド）１ａ，１ａ’を片持ち支持する実施例を示す。４８２は、例えば３チャンネルを備えた検査ユニット（検出ヘッド）１ａ，１ａ’を搭載した板状部材であり、この板状部材の下側にミラー３５を取り付けている。しかし、ミラー３５は、後述するように、必ずしも、板状部材４８２に取り付ける必要はない。そしてこの板状部材４８２は、基台４８１に対して片持ち支持で装着できるように構成されている。このように構成することによって、検査ユニット（検出ヘッド）１ａ，１ａ’の取り外しを容易にすることができる。この取り外し機構は、鋼球あるいはころ４８３を利用しているため、取り外しても再設置の際位置が再現され、再調整の手間を省く効果がある。
【００９７】
次に図１、図９及び図１０に示す実施例と同様に、更に異物検査装置１を構成する検査ユニット（検出ヘッド）１ａ、１ａ’のプロセス成膜装置への適用について図４９〜図５１に基づいて説明する。即ち、半導体の生産は、効率生産を目的に大口径化が進んでいる。また、製品完成までの日数（工完日数）の短縮が叫ばれている。枚葉処理は上記の課題を対策する方法として成膜装置、エッチング装置などの処理装置で進んでいる。さらに、これらの装置を安定に稼働させ、かつ上記の工完日数をのばさないようにする必要がある。本発明は、ウエハの処理前後の搬送中に異物欠陥の検査をすることにより、この課題を解決するものである。具体的には、多くのプロセス処理装置で、図１０、図５０に示すような、中心搬送室１０４を中心にしたマルチチャンバ方式が用いられている。この方式に共通した中心搬送室１０４上に、今まで説明した検査ユニット１ａ、１ａ’を設置する構成としている。このようにすることにより、異物検査装置１と、プロセス処理装置の設置上のインターフェイスを規格化することができ、異物検査装置１の適用をなめらかにできる。ここでは、中心搬送室１０４に設置したが、マルチチャンバの一室（予備室）５０１に設置しても良い。さらに、これらの処理装置では一度真空内に入れたウエハを大気に開放せずに複数の処理を施すことがある。このような場合、真空内のウエハ上の異物を検査する必要がある。そこで、真空内のウエハを、図１０と同様に、図４９に示す真空室に設置された窓（ダミー・ポート）１０６ｄを介して、大気中に設置した検査ユニット（検出ヘッド）１ａ、１ａ’を用いて真空室内のウエハ上の異物を検出する。ここで、図４９に示した、真空窓１０６ｄを含むフランジを規格品とすればよい。
【００９８】
図５１（ａ）には、照明光学系３１のミラー３５を真空室（搬送室）１０４内に設置すべく、真空対応標準フランジ１０６に取り付けた実施例を示したものである。図５１（ｂ）には、照明光学系３１のミラー３５を真空室（搬送室）１０４内に設置すべく、窓（ダミー・ポート）１０６ｄの下側に取り付けた実施例を示したものである。照明光をウエハ４の表面に対して角度αが少なくとも６０度以上で照明しようとするとミラー３５を真空室（搬送室）１０４に設置せざるを得なくなる。即ち、透明な窓を通して斜め方向から照明したのでは、集光性が確保できなくなるからである。また、検出光学系３６の対物レンズ３７としては、異物の検出感度を向上させるために、ＮＡ（開口数）の大きな（例えば０．２）、即ち焦点距離ｆの短い（例えばｆ＝４０ｍｍ程度）小形のレンズを使用した方がよい。そうすると透明窓１０６の下面と搬送されるウエハ４の表面との間の間隙が（例えば２０ｍｍ程度）非常に狭くなる。従って、図１０（ｂ）に示すように、ミラー３５を大気中においた場合、真空対応標準フランジ１０６を標準化できなくなると共に該真空対応標準フランジ１０６の下面とウエハ４の表面との間に間隙を形成することが難しくなる。一方、ミラー３５を真空室内に設置した方が、真空対応標準フランジ１０６を標準化できると共に、ミラー３５が搬送されるウエハ４の表面に余裕をもって接触しないようにミラー３５を設置することは可能となる。
【００９９】
検査ユニット（検出ヘッド）１ａ、１ａ’が真空窓１０６から切り離して設置され，位置調整可能なタイプの場合、搬送アーム５ａに対する光学系の位置調整が容易である。つまり、検査ユニット（検出ヘッド）１ａ、１ａ’を取り外し、更に取り付けるような場合、この設置時に必要な調整は、光学系３１、３６の全体のｚ方向と光学系３１、３６が持つ直線状の視野の傾きとの２自由度の調整だけになる。また、先に説明したウエハ４のそりに追従した自動傾き補正、及び自動焦点などの機構を用いる場合、この光学系３１、３６が真空窓１０６から切り離して設置され、位置調整可能なタイプが必然である。（もちろん、照明光学系３１の光強度が十分にあり、照明光束を十分広くできるような場合は、自動焦点も、自動傾き補正も検出光学系３６だけで良いため、照明用のミラー３５等の一部の部品が真空窓１０６側に設置されていても問題ない。）また、このようなタイプの検出系の場合、真空装置でない処理装置に設置する場合もそのまま検査ユニット（検出ヘッド）１ａ、１ａ’を設置できるという効果がある。ただし、検出光学系３６の対物レンズ３７の開口数（ＮＡ）が大きい（例えば０．２〜０．３）場合、対物レンズの収差が問題になり、予め真空窓１０６を考慮に入れてレンズ系を設計する必要があるため、大気中でもここで示したような窓を収差補正用に用いる必要がある。
また、検査ユニット（検出ヘッド）１ａ、１ａ’の取り外しを容易にする構成を図４８に示す。これは、鋼球あるいはころ４８３を利用し、取り外しても再設置の際位置が再現され、再調整の手間を省く効果がある。
また、図５１（ｂ）に示すように、照明用のミラー３５を真空窓１２６ｄに接着する構造は、フランジ１０６の構造を単純にする効果を有する。この場合、検出光学系３６とウエハ４の表面との間の間隙を多くとることができるので、窓ガラス１０６ｄ、フランジ１０６とも厚くできる効果がある。
【０１００】
ウエハ４上に成膜された膜の粒径が大きいような工程の場合、照明はできる限り大きな入射角度（αが６０度に近い角度）で入射するのが望ましい。逆に、ウエハ上に成膜された膜の粒径が小さく膜質が殆ど鏡面に近い工程の場合、照明はできる限り小さな入射角度（αが８０〜８５度）で入射するのが望ましい。これは、入射角が大きいと、膜の粒径からの反射がおさえられ、異物が強調されるからである。また、膜質が鏡面に近い場合は、より前方散乱を検出できるように、入射角は小さい方がよい。従って、本発明のオンマシン異物検査装置のような場合、各装置毎に成膜する膜が決定されているのであるから、膜に合う入射角度が選択されるべきである。
【０１０１】
また図５２に示すように、検出光学系３６の対物レンズ（テレセントリック光学系）３７の先に迷光を遮光する遮光板（フィルタ）５２１、５２２を設置する方が望ましい。即ち、前述した実施例においては、照明光学系３１により、強力な照明を用いるためウエハ表面あるいはレンズ表面での反射が原因になって、リニアイメージセンサ４０で検出する検出像に迷光が入ることがある。そこで図５２に示すような遮光板５２１、５２２を検出光学系３６の光路に設置する。これは、リニアイメージセンサ（検出器）４０が線状であり、レンズの全光束の内すべてを有効に活用していないため、活用されない部分は遮光してしまうと言う思想である。この効果をさらに有効にするため、この遮光板５２１、５２
２を複数段設置するのがよい。更に、検査ユニット（検出ヘッド）１ａ、１ａ’を室内の照明が入らないようにカバーできないような場合においても、室内の照明の影響を受けることもない。
【０１０２】
［第１１実施例］
次に異物検査における走査モード（搬送モード）について、図５３〜図５６を用いて説明する。図５３（ａ）（ｂ）に、一般的なウエハハンドリング機構（ウエハ搬送ロボット）５を示す。このような構成（肩部５ｃと該肩部５ｃに垂直軸回りにモータ（図示せず）によって回転駆動される上腕のアーム５ｂと該上腕のアーム５ｂの先端に垂直軸回りにモータ（図示せず）によって回転駆動される前腕のアーム５ａとで構成される。）のロボットでは、搬送アーム５ａの回転が等速度の場合、ウエハ４の搬送速度は等速にならない。この結果、リニアイメージセンサ４０で異物を検出するとき、画素サイズが場所により変動したり、蓄積時間が変わることにより検出出力が変動したりすることがある。これは、前述したように（図２２〜図２５）、チップ比較の対応点を算出する際に問題になる。
【０１０３】
そこで、１）ロボットが直線運動になるような制御をする、２）検出した画像平面がゆがまないように検出時の蓄積時間を制御する、３）画像はゆがんだまま取り込んで電気回路によるウエハの回転補正時にチップ比較の対応点を対応させる、等の処理を施す必要がある。
【０１０４】
このようなタイプのロボットでは、各時間に図５４（ｂ）に示したようなサインカーブの速度の運動をする。したがって、各時間には図５４（ａ）に示したようなサインカーブの位置に移動する。即ち、前述したように、上記のタイプのロボットでは、ウエハの位置ｘは、次の（６）式の関係を有し、時間ｔと共に図５４（ａ）に示したようなサインカーブになる。
ｘ＝ｌ・ｓｉｎ（ωｔ） （６）
ここで、ωはロボットの回転軸の各速度である。従って、ウエハの走査速度は、ｘを時間微分したｘドットで表され、次の（７）式の関係となり、図５４（ｂ）で示される。
ｘ（ドット）＝ｌ・ω・ｃｏｓ（ωｔ） （７）
このようなステージを用いる場合の対応方法の内、３）の電気回路によるウエハの回転補正時にチップ比較の対応点を対応させる方法について図５６（ａ）に基づいて説明する。この方法では、ウエハ４が載置された状態で、まずウエハの傾きθが回転検出処理１８６においてウエハ回転方向検出器１１０から検出される信号に基づいて算出され、このウエハの傾きθに応じて、参照テーブル５６１により比較対象のチップの座標関係（ｍpx，ｍpy）が求められる。この座標関係（ｍpx，ｍpy）に応じて、メモリ１８９上に格納された検出信号から、比較演算手段１９０により比較対象チップの情報が引き出され比較される。ここで、参照テーブル５６１は、演算処理を高速にするために用いられているものであり、必ずしも必要なものではない。参照テーブル５６１は、ウエハ走査の非等速性に対応するものである。ウエハの走査速度（ｘ（ドット））は、ロボットアームの各位置で一意的に決まり、ある速度で運動した際の検出画像ゆがみも一意的に決まるため、ロボットアーム５ａ，５ｂの各位置で検出画像ゆがみは一意的に決まる。そこで、ロボットアーム５ａ，５ｂの各位置毎にチップ比較時の対応点の位置座標を対応させることができる。この対応関係を参照テーブル５６１とする。
【０１０５】
一例として、ロボットの腕の長さｌ＝１００ｍｍ，腕の初期位相ε０＝３０度（腕の回転位相範囲−３０度＜ε＜３０度）、ロボットの回転パルスレートｆ０、画素サイズｐｓ＝７ミクロン、蓄積時間ｔｉ＝１ｍｓｅｃ、最大速度ｖｍ＝７ｍｍ／ｓｅｃの場合、チップピッチｐ＝１０ｍｍのウエハがθ＝５度の傾きを持って走査される時について具体的数値を算出してみる。
比較チップの関係座標をｘ方向、ｙ方向それぞれの差画素数（ｍpx、ｍpy）で示す。
ｍpx＝ｐ・ｓｉｎθ／ｐｓ＝１２４
ｍpy＝ｐ・ｃｏｓθ／ｐｓ＝１４２３
ここで、最大速度で搬送されている場合は、この値で、検出画素は正方形となる。ここで、搬送速度ｖ＝０．８・ｖｍの時、ｍpx＝１２４画素、ｍpy＝１４２３画素では、正方形にならない。
この速度で搬送して、正方形にするためには、
ｍpx＝（ｐ・ｓｉｎθ／ｐｓ）・（ｖｍ／ｖ）＝１５５
ｍpy＝（ｐ・ｃｏｓθ／ｐｓ）＝１４２３
となる。
ここで、腕の回転位相範囲が−３０度＜ε＜３０度程度の時は、上記のような近似式でも特に問題はないが、これより広い場合、あるいは、さらに高精度で管理したい場合は、以下の近似を用いない方法を用いて参照テーブル５６１を作成するのがよい。
【０１０６】
ｘ（ｍ）＝ｖｍ・（ｆ０／２π）ｓｉｎ（２π・ｎ／ｆ０−ε０）＋Ｃ（積分定数）
ここで、ｍ＝（２・ｌ／ｐｓ）・ｎの時、ｘ（ｍ＋ｍpx）−ｘ（ｍ）＝ｐ・ｓｉｎθを満たすように、ｍpxを算出する。ｍpyは変化しない。
参照テーブル５６１は、ｎに対応して、ｍpx，ｍpyを算出しておけばよい。
また、２）検出した画像平面がゆがまないように検出時の蓄積時間を制御する方法について説明する。
この方法は、図５５に示すウエハ（搬送アーム）の速度曲線（ｘ（ドット））を予め知っておきこの曲線に対応してリニアイメージセンサ（検出器）４０の蓄積時間を変化させるものである。各検出画素が正方形（リニアイメージセンサ（検出器）４０が正方形でない場合は、リニアイメージセンサ（検出器）４０の画素形状に相似な図形、たとえば長方形）になるように蓄積時間を変化させるものである。このためには、ステージの走査速度（ｘ（ドット））の逆数Ｔｉに比例するような蓄積時間にすれば、各位置で縦横の倍率が一定になる。
【０１０７】
即ち、図５６（ｂ）に示すように、ステージパルスカウンタ５６２により搬送ロボット５のエンコーダから検出されるロボットアーム５ａ，５ｂの回転角度からウエハ（搬送アーム）の送り位置（ｘ）が計測され、この位置毎に演算手段５６３によりウエハ（搬送アーム）の速度（ｘ（ドット））が算出され、この速度から蓄積時間が算出される。タイミング発生手段５６４では、演算手段５６３で算出された蓄積時間でニリアイメージセンサ４０からの信号が検出されるようにタイミング信号５６５を発生する。この信号５６５を用いて検出された画像信号ｉは、検出の時点で、ゆがみがない状態で一時的にメモリ１８９に格納される。一方、図２３に示すように、θ検出処理１８６でウエハの傾きθが検出され、この値と設計データからのチップピッチｐを基に対応点の座標を作成し、この座標を基にメモリ１８９に格納されているデータを引き出し対応点を比較演算手段１９０で比較することにより異物を示す信号１８８を検出することができる。
【０１０８】
ここで、検出信号ｉは、蓄積時間が異なるため、大きさが真の値からずれてしまう。この検出信号ｉのずれも、上記の方法に準ずる方法で、補正可能なのは言うまでもない。ところが、この補正により、ノイズも強調されてしまうことがある。故に、機構によりθ合わせを実施した後に信号を検出する方法が、最も良いデータを与える。
【０１０９】
［第１２実施例］
次に鏡面ウエハを保有するプロセス装置について図５７を用いて説明する。
図５７に鏡面ウエハを搭載したプロセス装置の実施例を示す。本発明に係わる異物検査システムでは、主に表面にパターンニングされた製品ウエハの異物を検査あるいはモニタする。ここで、表面にパターンがないウエハ（鏡面ウエハ）では、製品ウエハより高感度で異物を検査できる。そこで、プロセス装置の異物管理を鏡面ウエハを用いて実施することができる。ところが、この鏡面ウエハの異物検査では、装置からのウエハの搬送を含め時間と手間がかかっていたため、高頻度の検査ができないのが現実であった。また、鏡面ウエハの洗浄保管の手間も問題であった。
そこで、装置自体に鏡面ウエハのストッカ５７１を設置し、特定の頻度で、この鏡面ウエハ４ａを装置内を搬送し、本発明に係わるオンマシン異物検査装置１の検査ユニット１ａ，１ａ’で、表面検査を実施する構成とした。これにより、上記の問題を解決して、高頻度の装置異物モニタリングが実現される。
【０１１０】
本発明の装置は、ウエハストッカ５７１、昇降システム５７２、カセット室１０２、１０３、搬入口５７３、異物検査ユニット１ａ，１ａ’、搬送アーム５ａ、搬送ロボット５、中央搬送室１０４、プロセス処理室１０１等構成される。ここで、ウエハ４は、カセット（１ロット２５枚のウエハが運搬されるタイプ、あるいはその他の数値の複数枚のウエハが運搬されるもの、あるいは、枚葉のウエハが運搬されるもの）１３２に載置された状態で、搬入口５７３から搬入される。ここで、ウエハカセット１３２の載置される位置に、載置されたウエハ４がそれぞれ平行になる状態で、鏡面ウエハ４ａを載置するウエハストッカ５７２が設置されている。鏡面ウエハ４ａを載置するウエハストッカ５７２の位置は、この位置でなくても搬送アーム５ａが搬送しやすい他の場所であっても良い。
【０１１１】
ここで、通常は、ウエハカセット１３２内のウエハ４が処理される。ここで、任意のタイミング、具体的には、ウエハ１ロット（１カセット）毎、あるいは数ロット毎、あるいは１日に１回等のタイミングで、ウエハストッカ５７２内の鏡面ウエハ４ａが搬送される。ウエハは、任意の搬送経路、具体的には、プロセス処理を含む通常の搬送経路、あるいは短縮された経路等の経路で搬送後、異物検査ユニット１ａ，１ａ’で、表面異物が検査される。
さらに、この鏡面ウエハ４ａは、使用してウエハストッカ５７２に収納する毎に洗浄するわけではないので、使用する度に鏡面ウエハ４ａ上の異物は徐々に増えていくが、この変化が急峻でない限りは、特に問題にならない。そこで、このモニタリングでは、搬送前（前回の検査結果）の異物付着マップ（図５８（ａ）に示す状態）と搬送後の異物付着マップ（図５８（ｂ）に示す状態）の差を取り、この差（図５８（ｃ）に示す状態）を、検査データとする。このようにして、鏡面ウエハ４ａ上に付着した異物の状態を検出することができる。
【０１１２】
次に窓部での異物付着モニタについて説明する。ここで、鏡面ウエハ４ａの代わりに、プロセス処理室に設置された観察窓の内面を検査ユニット１ａで直接検査あるいはモニタリングしても良い。この場合、表面は、鏡面であるため高感度で検査が可能である。また、鏡面ウエハ４ａの搬送ストックなどの煩雑さがない。また、処理中、処理間、等常時モニタできる等の効果がある。ここで、検査ユニット１ａは、前述したような１次元検出器を走査して用いても良いし、２次元の検出器を用いても良い。さらに、ウエハ表面異物との関係を事前に把握しておき、ウエハ表面に異常が発生したようなときの観察窓の様子を予めデータベースに格納しておくと、ウエハの表面の観察をせずとも観察窓の表面検査だけで装置の発塵状態を知ることができる。
【０１１３】
ここで処理室壁面、観察窓を含む内面は、プロセス処理と共にゆっくり汚染されていく。この様子は、異物検出信号（異物の数あるいは検出信号強度）の緩やかな変化として観察される。ここで、表面からの膜離れ、あるいは、異常な異物発生が合った場合、前記の緩やかな変化ではない、急峻な変化が観察される。この急峻な変化は、急峻な増加だけでなく、急峻な信号減少であっても異常とされるべきである。表面の膜のはがれの場合、急峻な信号減少として観察されることが多い。
このような異常を検出した場合、処理室壁面の掃除、その他の対策が施される。さらに、観察窓は、異物が付着するという点で装置内の壁面と同等の性質を持っているのが望ましい。具体的には、温度、表面の粗さ、材質（薄い金属膜等を蒸着し材質を同じにしておく。この場合、薄い金属膜は光を透過する。）等を同じにしておくのが望ましい。
【０１１４】
次にシェーディングの補正について説明する。本発明では、隣接チップ間で信号出力を比較するため、照明はより均一な強度で照射されるべきである。ところが、レーザのビームは一般的に中心が強く周辺が弱い。結果的に、照明強度は、直線上の視野の中央付近で強く周囲で弱くなっている。そこで、図３に示す照明光学系３１の射出位置付近（シリンドリカルレンズ３４の前に）にこの強度分布を逆に補正するような補正板を挿入する。この補正板は、曲線状のスリットであってもよく、中央付近の透過率を落としたＮＤフィルターであってもよい。
【０１１５】
【発明の効果】
本発明によれば、半導体ウエハ、ＴＦＴ基板等の半導体基板に対して成膜するスパッタ装置及びＣＶＤ装置、パターンを形成するエッチング装置、レジスト塗布装置、露光装置、洗浄装置等の様々なプロセス処理装置において、半導体ウエハ、ＴＦＴ基板等の半導体基板に対して異常な付着異物の発生を低減して半導体を高歩留まりで生産することができる効果を奏する。
【０１１６】
また本発明によれば、半導体ウエハ、ＴＦＴ基板等の半導体基板に対して成膜するスパッタ装置及びＣＶＤ装置、パターンを形成するエッチング装置、レジスト塗布装置、露光装置、洗浄装置等の様々なプロセス処理装置において、半導体ウエハ、ＴＦＴ基板等の半導体基板に対して異常な付着異物の発生に対してアラーム等のフィードバックを行うことができ、このフィードバックに基づいて部分的に、または全体について洗浄したり、供給ガスの条件、排気の条件、温度条件、印加電圧等のプロセス条件を制御することにより異常な異物の発生を著しく低減して半導体を高歩留まりで生産することができる効果を奏する。
【０１１７】
また本発明によれば、半導体ウエハ、ＴＦＴ基板等のワーク（半導体基板）を多数保管する製品保管装置において、多数のワーク上に付着した異物の状態を調べてワークを排出することができるので、多数の異物が付着したワークに対してその後のプロセス処理を続行することを防止することができ、その結果半導体を高歩留まりで生産することができる効果を奏する。
【図面の簡単な説明】
【図１】本発明に係わるプロセス処理装置に異物検査装置を設置した場合の実施例を示した図である。
【図２】本発明に係わる全体のシステム構成を示した図である。
【図３】本発明に係わる検査ユニット（検出ヘッド）の具体的構成を示す図である。
【図４】本発明に係わる検査ユニット（検出ヘッド）におけるチャンネル数と走査の仕方との関係を示した図である。
【図５】本発明に係わる処理による増加異物マップの算出の仕方を説明するための図である。
【図６】本発明に係わる着工ロット単位或いはウエハ単位に検出される異物数を示す図である。
【図７】本発明に係わる着工ロット単位において、ウエハ毎に最大、最小、平均値の異物数を示す図である。
【図８】本発明に係わる過去の解析事例に基づいて異常の異物発生原因を推定する仕方を説明するための図である。
【図９】本発明に係わるプロセス処理装置に異物検査装置を設置した場合の図１とは異なる実施例を示した図である。
【図１０】本発明に係わるプロセス処理装置に異物検査装置を設置した場合の図１及び図９とは異なる実施例を示した図である。
【図１１】本発明に係わる異物検査装置にウエハコード識別装置を備えたシステム構成を示す図である。
【図１２】本発明に係わる識別コードが印字されたウエハを示す図である。
【図１３】本発明に係わるウエハストッカに異物検査装置を設置した場合の実施例を示した図である。
【図１４】図１３に示す保管棚の部分を示す図である。
【図１５】本発明に係わるウエハのオリフラを検出してウエハ回転方向を検出する実施例を説明するための図である。
【図１６】本発明に係わるウエハのオリフラを検出してウエハ回転方向を検出する図１５と異なる実施例を説明するための図である。
【図１７】本発明に係わるウエハ上に形成されたチップ格子を検出してウエハ回転方向を検出する実施例を説明するための図である。
【図１８】本発明に係わるウエハ上に形成されたチップ格子を検出してウエハ回転方向を検出する図１７と異なる実施例を説明するための図である。
【図１９】本発明に係わるウエハ上に形成されたチップ格子を検出してウエハ回転方向を検出する図１７及び図１８と異なる実施例を説明するための図である。
【図２０】本発明に係わるウエハ上に形成されたチップ格子を検出してウエハ回転方向を検出する図１７及び図１８及び図１９と異なる実施例を説明するための図である。
【図２１】本発明に係わる検出像からウエハの回転角を検出する仕方を説明するための図である。
【図２２】本発明に係わるチップ比較において回転補正オペレータを施すための説明図である。
【図２３】本発明に係わるソフト処理で行うチップ比較システムを示す図である。
【図２４】図２３の説明図である。
【図２５】本発明に係わる回転機構を用いて行うチップ比較システムを示す図である。
【図２６】図２５の説明図である。
【図２７】本発明に係わる検出像からウエハの回転角を検出するための説明図である。
【図２８】照明光とウエハからの回折光と対物レンズの開口数との関係を示す正面図である。
【図２９】照明光とウエハからの回折光と対物レンズの開口数との関係を示す平面図である。
【図３０】ウエハのチップ配列方向を示す図である。
【図３１】空間フィルタで０次回折光を遮光する説明図である。
【図３２】本発明に係わる検査ユニットにおける検出光学系の焦点深度とワーク検査面との関係を示す図である。
【図３３】本発明に係わるハンドリング機構（搬送ロボット）の搬送アームにおいて、ウエハを吸着する構成を示す図である。
【図３４】ウエハのそりに基づいて、ウエハの傾きを検出する光学系の実施例を示す図である。
【図３５】ウエハのそりに基づいて、ウエハの傾きを検出する光学系の図３４と異なる実施例を示す図である。
【図３６】ウエハのそりに基づいて、空間フィルタの位置における０次回折光のずれを示す図である。
【図３７】合傾範囲を示す図である。
【図３８】検査ユニット（検出ヘッド）を傾き合わせ、及び自動焦点合わせさせるための機構を示す図である。
【図３９】自動焦点合わせさせるための検出光学系を示す図である。
【図４０】精密に自動焦点合わせさせるための検出光学系を示す図である。
【図４１】自動焦点合わせするための各種信号処理波形を示す図である。
【図４２】自動焦点合わせするための信号波形を示す図である。
【図４３】信号ａ，ｂ、（ａ−ｂ）／（ａ＋ｂ）とΔＺとの関係を示す図である。
【図４４】信号ａ，ａ’，ｂ，ｂ’、（ａ−ｂ）／（ａ＋ｂ），（ａ’−ｂ’）／（ａ’＋ｂ’）とΔＺとの関係を示す図である。
【図４５】照明光学系の照明光束を用いて傾き検出と焦点検出とを行う光学系を示す正面図である。
【図４６】照明光学系の照明光束を用いて傾き検出と焦点検出とを行う光学系を示す平面図である。
【図４７】検査ユニット（検出ヘッド）をウエハ平面内で回転ずれ補正させる機構を示す斜視図である。
【図４８】検査ユニット（検出ヘッド）を簡単に装着させる機構を示す図である。
【図４９】本発明に係わるプロセス処理装置の搬送室上蓋に装着するダミー・ポートを示す図である。
【図５０】本発明に係わるプロセス処理装置において、予備室に検査ユニットを設置した場合の実施例を示す図である。
【図５１】本発明に係わるプロセス処理装置において、検査ユニットを搬送室の外側に設置して、照明光学系のミラーを搬送室内に設置した実施例を示す図である。
【図５２】本発明に係わる検査ユニットにおいて迷光を遮光する実施例を示す図である。
【図５３】本発明に係わるハンドリング機構（搬送ロボット）でウエハを搬送する場合についての説明図である。
【図５４】本発明に係わるハンドリング機構（搬送ロボット）でウエハを搬送する場合において変位ｘとその速度（ｘ（ドット））との関係を示す図である。
【図５５】本発明に係わるハンドリング機構（搬送ロボット）でウエハを搬送する場合において速度（ｘ（ドット））とその逆数Ｔｉとの関係を示す図である。
【図５６】本発明に係わるチップ比較においてハンドリング機構（搬送ロボット）でウエハを搬送する場合における速度変動を考慮して行う構成と、本発明に係わるハンドリング機構（搬送ロボット）でウエハを搬送する場合における速度変動を考慮してリニアイメージセンサにおける蓄積時間を制御する構成を示す図である。
【図５７】本発明に係わるプロセス処理装置において、検査ユニットでストックした鏡面ウエハを用いて異物検出を行う実施例を示す図である。
【図５８】図５７に示す実施例において鏡面ウエハを用いた場合の異物検出データを得る手法を説明するための図である。
【符号の説明】
１…異物検査装置、１ａ，１ａ’…検査ユニット（検出ヘッド）、
１ｂ…走査ステージ、３…Θステージ、４…ワーク（ウエハ）、
５…ハンドリング機構（搬送ロボット）、５ａ…搬送アーム、
６…バッファチャンバ、７…プロセス処理室、
８ａ，８ｂ…ワーク供給用ステーション（ローダ、アンローダ）、
９…データ処理部（ＣＰＵ）、１０…制御装置、１１…検査制御装置、
２０…異物データ解析コンピュータ、２０ｇ…データベース（ハードディスク）、
２１…分析装置、２２…検査装置、３１…照明光学系、３５…ミラー、
３６…検出光学系、３９…空間フィルタ、
３７…テレセントリック光学系（対物レンズ）、４０…リニアイメージセンサ、
４１…照明された線状の光束、９１…プロセス処理装置、９２…処理室、
９４…ガス流量測定ユニット、９５…ガス圧測定ユニット、
９６…放射率測定ユニット、設備状態データ収集、９８…ローディング室、
９９…アンローディング室、１０１…反応室、１０２…ローダ部、
１０４…搬送室、１０５…上蓋、１０６…真空対応標準フランジ、
１１０…ウエハ回転検出系、１１１…ウエハコード識別装置、
１３１…ウエハストッカ、１３２…ウエハカセット、
１３３…ウエハカセット搬送ロボット、１８７…回転補正オペレータ、
１８９…メモリ、１９０…比較処理手段、１８６…回転検出処理。[0001]
[Industrial application fields]
The present invention relates to a semiconductor wafer in various process processing apparatuses such as a sputtering apparatus and a CVD apparatus for forming a film on a semiconductor substrate such as a semiconductor wafer and a TFT substrate, an etching apparatus for forming a pattern, a resist coating apparatus, an exposure apparatus, and a cleaning apparatus. , A process processing apparatus and its system capable of producing a semiconductor substrate at a high yield by reducing the occurrence of abnormal adhered foreign matter on a semiconductor substrate such as a TFT substrate, and product storage for storing a large number of workpieces such as semiconductor wafers. Relates to the device.
[0002]
[Prior art]
Japanese Patent Laid-Open No. 5-218163 and Japanese Patent Laid-Open No. 3-44054 are known as conventional techniques related to the semiconductor production method and the system thereof.
[0003]
[Problems to be solved by the invention]
However, the above-described prior art includes various process processes such as a sputtering apparatus and a CVD apparatus for forming a film on a semiconductor substrate such as a semiconductor wafer and a TFT substrate, an etching apparatus for forming a pattern, a resist coating apparatus, an exposure apparatus, and a cleaning apparatus. In the apparatus, the problem of reducing the generation of abnormal adhered foreign matters to a semiconductor substrate such as a semiconductor wafer or a TFT substrate so that the semiconductor substrate can be produced at a high yield has not been sufficiently considered.
[0004]
In order to solve the above problems, an object of the present invention is to provide a sputtering apparatus and a CVD apparatus for forming a film on a semiconductor substrate such as a semiconductor wafer and a TFT substrate, an etching apparatus for forming a pattern, a resist coating apparatus, an exposure apparatus, and a cleaning apparatus. To provide a process processing apparatus and a system capable of producing a semiconductor substrate at a high yield by reducing the occurrence of abnormal adhered foreign matter on a semiconductor substrate such as a semiconductor wafer and a TFT substrate in various process processing apparatuses It is in.
[0005]
Another object of the present invention is to provide a product storage device that checks the state of foreign matter adhering to a large number of workpieces such as semiconductor wafers and discharges the workpieces.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention detects foreign matter adhering to a workpiece transported by a handling mechanism in a transport chamber in a process processing apparatus such as a sputtering apparatus, a CVD apparatus, or an etching apparatus. In this way, the illumination optical system that irradiates the light beam focused from the oblique direction with respect to the surface of the workpiece and the scattered light from the foreign matter on the workpiece irradiated by the illumination optical system is collected and received by the photoelectric conversion means A foreign matter detection apparatus comprising: a detection head composed of a plurality of sets of detection optical systems to be detected in addition; and a processing means for processing a signal detected from a photoelectric conversion means of the detection head and extracting a signal from the foreign matter A process processing apparatus is provided. The present invention also includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transport chamber of the process processing device in a processing device such as a sputtering device, a CVD device, or an etching device. Is a process processing apparatus characterized by Further, the present invention provides a transparent processing apparatus in which a foreign matter adhering to a workpiece conveyed by a handling mechanism in a transfer chamber in the process processing apparatus is provided in an upper lid of the transfer chamber in a process apparatus such as a sputtering apparatus, a CVD apparatus, or an etching apparatus. A process processing apparatus comprising a foreign object detection device for detecting through a window. According to another aspect of the present invention, there is provided a process processing apparatus such as a sputtering apparatus, a CVD apparatus, an etching apparatus, or the like, wherein a foreign substance detection device for detecting foreign substances adhering to a workpiece processed in the processing chamber is provided in the spare chamber. It is a processing device. Further, the present invention is a process processing apparatus such as a sputtering apparatus, a CVD apparatus, or an etching apparatus, which adheres to a work (semiconductor wafer, TFT substrate, etc.) transported by a handling mechanism in a transport chamber or a spare chamber in the process processing apparatus. A foreign matter detection device for detecting foreign matter is provided, and the state of foreign matter attached to the workpiece (the number of attached foreign matter or the attached foreign matter map (distribution)) in the process processing device detected by the foreign matter detection device is managed in units of a lot or a wafer. A process processing apparatus comprising a management means.
[0007]
Further, the present invention is a process processing apparatus such as a sputtering apparatus, a CVD apparatus, or an etching apparatus, which adheres to a work (semiconductor wafer, TFT substrate, etc.) transported by a handling mechanism in a transport chamber or a spare chamber in the process processing apparatus. A foreign matter detection device for detecting foreign matter is provided, and the state of foreign matter attached to the workpiece (the number of attached foreign matters or the attached foreign matter map (distribution)) in the process processing device detected by the foreign matter detection device is temporally measured in units of construction lots or wafers. The process processing apparatus is characterized by comprising management means for managing whether or not there is a tendency to increase.
[0008]
The present invention also provides a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transport chamber or a spare chamber in a process processing device such as a sputtering device, a CVD device, or an etching device. A foreign matter state (the number of attached foreign matters or an attached foreign matter map (distribution)) on a workpiece in the process processing apparatus detected by the foreign matter detecting device is managed in units of lots or wafers, and the lot units to be managed are managed Or, it is provided with a management control means for controlling the timing or cycle of the stop or cleaning of the process processing in the process processing apparatus (full cleaning or cleaning of only parts) based on the state of foreign matter adhering to the work in units of work. Is a process processing apparatus. The present invention also provides a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transport chamber or a spare chamber in a process processing device such as a sputtering device, a CVD device, or an etching device. Management means for managing the state of foreign matter adhering to the workpiece in the process processing device detected by the foreign matter detection device, in units of construction lots or wafers, and alarm generation means for generating an alarm when the management means recognizes an abnormality A process processing apparatus comprising:
[0009]
According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head composed of a plurality of detection optical systems for collecting and detecting the scattered light and detecting it by the photoelectric conversion means, and further processing the signal detected from the photoelectric conversion means to obtain a signal from a foreign substance. And a processing means for extracting. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head composed of a plurality of detection optical systems for collecting and detecting the scattered light and detecting it by the photoelectric conversion means, and further processing the signal detected from the photoelectric conversion means to obtain a signal from a foreign substance. And a rotation detecting optical system for optically detecting the orientation flat direction of the workpiece or the arrangement direction of the chips. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head comprising a plurality of detection optical systems for collecting and detecting the scattered light received by the photoelectric conversion means, and rotation for optically detecting the orientation flat direction of the workpiece or the arrangement direction of the chips A detection optical system and a signal detected from the photoelectric conversion means by performing rotation correction on the coordinates on the workpiece based on the orientation flat direction of the workpiece or the chip arrangement direction detected by the rotation detection optical system And processing means for extracting a signal from a foreign substance by performing chip comparison. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head comprising a plurality of detection optical systems for collecting and detecting the scattered light received by the photoelectric conversion means, and rotation for optically detecting the orientation flat direction of the workpiece or the arrangement direction of the chips From the pattern on the workpiece by performing relative rotation correction between the workpiece and the detection head based on the direction of the orientation flat of the workpiece detected by the detection optical system and the rotation detection optical system or the arrangement direction of the chips. Processing means for extracting a signal from a foreign substance on the basis of a signal detected from the photoelectric conversion means so that the generated zero-order diffracted light is not incident on the detection optical system. The features. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. And a detection head comprising a plurality of detection optical systems that detect and detect light by photoelectric conversion means through a spatial filter that collects the scattered light and shields the 0th-order diffracted light, and the orientation of the workpiece or the orientation of the chip Rotation detection optical system for optically detecting the arrangement direction, and relative rotation between the workpiece and the detection head based on the orientation of the orientation flat of the workpiece or the chip arrangement direction detected by the rotation detection optical system The zero-order diffracted light generated from the pattern on the workpiece after correction is shielded by the spatial filter, and the signal from the foreign matter is obtained based on the signal detected from the photoelectric conversion means. Characterized by comprising a processing means for output. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head comprising a plurality of detection optical systems for collecting and detecting the scattered light received by the photoelectric conversion means, and rotation for optically detecting the orientation flat direction of the workpiece or the arrangement direction of the chips A detection optical system and the next generation generated from the pattern on the workpiece by correcting the rotation of the detection head with respect to the workpiece based on the orientation flat direction of the workpiece or the arrangement direction of the chips detected by the rotation detection optical system. And processing means for extracting a signal from a foreign substance based on a signal detected from the photoelectric conversion means so that the folded light does not enter the detection optical system.
[0010]
According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. And a detection head comprising a plurality of detection optical systems that detect and detect light by photoelectric conversion means through a spatial filter that collects the scattered light and shields the 0th-order diffracted light, and the orientation of the workpiece or the orientation of the chip A rotation detection optical system for optically detecting the arrangement direction; and a rotation correction of the detection head for the workpiece based on the orientation flat direction of the workpiece or the chip arrangement direction detected by the rotation detection optical system. A processing means for extracting a signal from a foreign substance based on a signal detected from the photoelectric conversion means by blocking zero-order diffracted light generated from a pattern on a workpiece with the spatial filter. Characterized by comprising and.
[0011]
According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. It is characterized in that a detection head composed of a plurality of pairs with a detection optical system that collects the scattered light and receives and detects it with a photoelectric conversion means is detachably supported in a cantilever manner. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head composed of a plurality of pairs with a detection optical system that collects the scattered light and receives and detects it with a photoelectric conversion means, and is supported in a cantilever manner so as to be able to rotationally correct the workpiece. It is characterized by. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. And a detection head comprising a plurality of detection optical systems that collect and collect the scattered light received by a photoelectric conversion means and support it by a mechanism capable of rotationally correcting the workpiece. To do.
[0012]
According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head composed of a plurality of detection optical systems for collecting and detecting the scattered light and detecting it by the photoelectric conversion means, and further processing the signal detected from the photoelectric conversion means to obtain a signal from a foreign substance. A processing means for extracting; a rotation detection optical system for optically detecting the orientation flat direction of the workpiece or the chip arrangement direction; an inclination detection optical system for detecting the tilt of the workpiece surface; and a height of the workpiece surface. And a height detection optical system for detection. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head composed of a plurality of detection optical systems that collect and scatter scattered light received by a photoelectric conversion means, and detect a signal from a foreign substance by processing a signal detected from the photoelectric conversion means A rotation detecting optical system for optically detecting the orientation flat direction or chip arrangement direction of the workpiece, an inclination detecting optical system for detecting the tilt of the surface of the workpiece, and the tilt detecting optical system. And an inclination control mechanism for controlling the inclination of the detection head with respect to the workpiece in accordance with the detected inclination of the workpiece. According to the present invention, in the process processing apparatus, the foreign object detection device includes an illumination optical system that irradiates a light beam focused in an oblique direction with respect to the surface of the work, and a foreign object on the work that is irradiated by the illumination optical system. A detection head composed of a plurality of detection optical systems that collect and scatter scattered light received by a photoelectric conversion means, and detect a signal from a foreign substance by processing a signal detected from the photoelectric conversion means , A rotation detecting optical system for optically detecting the orientation of the workpiece or the arrangement direction of the chips, a height detecting optical system for detecting the height of the surface of the work, and the height detection And a height control mechanism for controlling the height of the detection head with respect to the workpiece in accordance with the height of the workpiece detected from an optical system.
[0013]
According to the present invention, in the process processing apparatus, the work is attracted to the transfer arm of the handling mechanism by electromagnetic attraction. According to another aspect of the present invention, a product storage device (wafer stocker) is provided with a foreign matter inspection device for measuring a foreign matter adhesion state on a workpiece stored in the product storage device. The present invention also includes a foreign matter inspection device for measuring the state of foreign matter adhesion to a workpiece stored in the product storage device in a product storage device (wafer stocker), and the foreign matter on the workpiece measured by the foreign matter inspection device. A product storage device comprising control means for controlling the delivery of a workpiece to the next process based on the adhesion state.
[0014]
According to the present invention, in the product storage apparatus (wafer stocker), the foreign matter detection apparatus irradiates a light beam focused from an oblique method with respect to a surface of the work, and a work irradiated by the illumination optical system. A detection head composed of a plurality of detection optical systems that collect and scatter scattered light from the above foreign matter and receive and detect it by the photoelectric conversion means, and further processing the signal detected from the photoelectric conversion means And a processing means for extracting a signal from. According to the present invention, in the product storage device, the foreign object detection device includes an illumination optical system that irradiates a light beam focused from an oblique direction with respect to a surface of the work, and a foreign matter on the work that is irradiated by the illumination optical system. A detection head composed of a plurality of detection optical systems for collecting and detecting the scattered light and detecting it by the photoelectric conversion means, and further processing the signal detected from the photoelectric conversion means to obtain a signal from a foreign substance. And a rotation detecting optical system for optically detecting the orientation flat direction of the workpiece or the arrangement direction of the chips.
[0015]
According to the present invention, in the product storage device, the foreign object detection device includes an illumination optical system that irradiates a light beam focused from an oblique direction with respect to a surface of the work, and a foreign matter on the work that is irradiated by the illumination optical system. A detection head comprising a plurality of detection optical systems for collecting and detecting the scattered light received by the photoelectric conversion means, and rotation for optically detecting the orientation flat direction of the workpiece or the arrangement direction of the chips A detection optical system and a signal detected from the photoelectric conversion means by performing rotation correction on the coordinates on the workpiece based on the orientation flat direction of the workpiece or the chip arrangement direction detected by the rotation detection optical system And processing means for extracting a signal from a foreign substance by performing chip comparison. According to the present invention, in the product storage device, the foreign object detection device includes an illumination optical system that irradiates a light beam focused from an oblique direction with respect to a surface of the work, and a foreign matter on the work that is irradiated by the illumination optical system. A detection head comprising a plurality of detection optical systems for collecting and detecting the scattered light received by the photoelectric conversion means, and rotation for optically detecting the orientation flat direction of the workpiece or the arrangement direction of the chips From the pattern on the workpiece by performing relative rotation correction between the workpiece and the detection head based on the direction of the orientation flat of the workpiece detected by the detection optical system and the rotation detection optical system or the arrangement direction of the chips. Processing means for extracting a signal from a foreign substance based on a signal detected from the photoelectric conversion means so that the generated 0th-order diffracted light is not incident on the detection optical system. And butterflies. According to the present invention, in the product storage device, the foreign object detection device includes an illumination optical system that irradiates a light beam focused from an oblique direction with respect to a surface of the work, and a foreign matter on the work that is irradiated by the illumination optical system. And a detection head comprising a plurality of detection optical systems that detect and detect light by photoelectric conversion means through a spatial filter that collects the scattered light and shields the 0th-order diffracted light, and the orientation of the workpiece or the orientation of the chip Rotation detection optical system for optically detecting the arrangement direction, and relative rotation between the workpiece and the detection head based on the orientation of the orientation flat of the workpiece or the chip arrangement direction detected by the rotation detection optical system The zero-order diffracted light generated from the pattern on the workpiece after correction is shielded by the spatial filter, and the signal from the foreign matter is extracted based on the signal detected from the photoelectric conversion means. Characterized by comprising a processing unit that.
[0016]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. A processing means for creating a foreign matter map of a work in the start lot unit or wafer unit based on the foreign matter state (the number of attached foreign matter or the attached foreign matter map (distribution)) on the workpiece in the process processing apparatus, and a workpiece in a known workpiece analysis example The storage means for registering the correspondence database between the foreign matter map and the cause thereof, and the foreign matter map of the workpiece in the start lot or wafer unit created by the processing means and the correspondence database registered in the storage means are compared. A process processing apparatus or a process It is a system.
[0017]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. Based on the state of foreign matter attached to the workpiece at least before or after process processing (number of attached foreign matter or attached foreign matter map (distribution)), the number of foreign matter attached to the workpiece in process processing is managed in units of lots or wafers. When the state of foreign matter adhering to the work in the start lot or work unit to be managed tends to increase due to changes over time or becomes abnormal beyond the control value, the process processing is stopped in the start lot or work unit. A process processing apparatus or a process processing, characterized by comprising control means for controlling the process processing. It is a system.
[0018]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. Process processing that is calculated by comparing the workpiece adhering foreign matter state (the number of adhering foreign matters or the adhering foreign matter map (distribution)) and the workpiece adhering foreign matter state (the number of adhering foreign matters or the adhering foreign matter map (distribution)) after processing. The state of foreign matter adhering to the workpiece is managed in units of lots or wafers, and when the state of foreign matter adhering to workpieces in the managed lot units or workpieces tends to increase due to changes over time or exceeds the control value Control means for controlling process processing by stopping process processing in units of construction lots or work units when an abnormality occurs A process apparatus or process processing system characterized by comprising.
[0019]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. Based on at least the state of foreign matter attached to the workpiece before or after process processing (the number of attached foreign matter or attached foreign matter map (distribution)), the state of foreign matter attached to the workpiece in process processing is managed in units of lots or wafers. When the state of foreign matter adhering to the workpiece in the start lot or workpiece unit to be managed tends to increase due to changes over time or becomes abnormal beyond the control value, it is registered from the detected foreign matter state on the workpiece. The cause of failure is estimated based on a database showing the correspondence between the foreign matter map of the workpiece and the cause of the failure A process apparatus or process processing system characterized by comprising a control means for controlling the process process to remove the the defective cause Te.
[0020]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. The state of foreign matter adhered to the workpiece in the process processing calculated by comparing the state of foreign matter adhered to the workpiece before processing and the state of foreign matter adhered to the workpiece after processing is managed in units of lots or wafers. When the number of foreign objects attached to a workpiece in lot units or workpiece units tends to increase due to changes over time, or when the value exceeds the control value, the registered workpiece is detected from the detected foreign object state on the workpiece. The cause of the defect is estimated based on the database indicating the correspondence between the foreign matter map and the cause of the defect, and the cause of the defect is removed. A process apparatus or process processing system characterized by comprising a control means for controlling a process treatment.
[0021]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. In addition, the state of foreign matter adhered to the workpiece in the process processing is managed in units of the start lot or wafer based on the state of the foreign matter attached to the workpiece before or after the process processing. When the foreign matter attached to the workpiece tends to increase due to changes over time, or when the control value exceeds the control value, the processing conditions of the registered process processing device and the workpiece are determined from the detected foreign matter attached to the workpiece. The defect processing conditions are estimated based on a database indicating the correlation with the foreign matter occurrence status on the A process apparatus or process processing system characterized by comprising a control means for controlling the processing conditions of the process treatment to remove the condition.
[0022]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. The state of foreign matter adhered to the workpiece in the process processing calculated by comparing the state of foreign matter adhered to the workpiece before processing and the state of foreign matter adhered to the workpiece after processing is managed in units of lots or wafers. The process registered from the detected foreign matter state on the workpiece when the foreign matter state on the workpiece in the lot unit or workpiece unit tends to increase due to time changes or becomes abnormal beyond the control value. Defect processing conditions are estimated based on a database that shows the correlation between processing conditions of the processing equipment and the occurrence of foreign matter on the workpiece. A process apparatus or process processing system characterized by comprising the control means for controlling the processing conditions of the process treated to remove the defective processing conditions Te.
[0023]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. Based on the state of foreign matter attached to a workpiece, the state of foreign matter attached to the workpiece in process processing is managed in units of lots or wafers. When there is a tendency to increase due to changes, or when an abnormality occurs beyond the control value, the detected foreign matter state on the workpiece is stored in a database indicating the correspondence between the registered foreign matter map of the workpiece and its cleaning condition. An execution means for estimating a cleaning condition based on the cleaning condition and executing cleaning in the process processing apparatus based on the cleaning condition is provided. A process apparatus or process processing system, characterized in that the.
[0024]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. The state of foreign matter adhered to the workpiece in the process processing calculated by comparing the state of foreign matter adhered to the workpiece before processing and the state of foreign matter adhered to the workpiece after processing is managed in units of lots or wafers. When the number of foreign objects attached to a workpiece in lot units or workpiece units tends to increase due to changes over time, or when the value exceeds the control value, the registered workpiece is detected from the detected foreign object state on the workpiece. The cleaning condition is estimated based on a database indicating correspondence between the foreign matter map and the cleaning condition, and a process is performed according to the cleaning condition. A process apparatus or process processing system characterized by comprising an execution means for executing the cleaning of the management device.
[0025]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. Based on the state of foreign matter attached to a workpiece, the state of foreign matter attached to the workpiece in process processing is managed in units of lots or wafers. When there is a tendency to increase due to changes, or when an abnormality occurs beyond the control value, a database indicating the correspondence between the foreign matter map of the registered workpiece and the process processing device is determined from the measured foreign matter state on the workpiece. Execution of identifying a process processing device based on and performing cleaning in the identified process processing device Process processing apparatus or process processing system characterized by comprising a stage.
[0026]
The present invention further includes a foreign matter detection device for detecting foreign matter adhering to a workpiece transported by a handling mechanism in a transfer chamber or a spare chamber in the process processing device, and the foreign matter detection device detects the foreign matter. The state of foreign matter adhered to the workpiece in the process processing calculated by comparing the state of foreign matter adhered to the workpiece before processing and the state of foreign matter adhered to the workpiece after processing is managed in units of lots or wafers. When the number of foreign objects attached to the work in lot units or work units tends to increase due to changes over time, or when it becomes abnormal beyond the control value, the registered work is determined from the measured state of foreign substances attached to the workpiece. The process processing device is identified based on the database indicating the correspondence between the foreign matter map and the process processing device. Process processing apparatus or process processing system characterized by comprising an execution means for executing the cleaning in the process apparatus.
[0027]
In addition, the present invention is characterized in that a common interface is provided for various process apparatuses or simple stages, and that one detection head can be used as a plurality of apparatuses or a single inspection machine by being replaced with these apparatuses. The present invention further includes a code identification device for identifying a code such as a product type, a lot number, and a wafer number printed on a workpiece (semiconductor substrate) processed by various process processing apparatuses. In the present invention, foreign matter data corresponding to the process processing apparatus is extracted.
[0028]
[Action]
With the above-described configuration, a semiconductor is used in various process processing apparatuses such as a sputtering apparatus and a CVD apparatus for forming a film on a semiconductor substrate such as a semiconductor wafer and a TFT substrate, an etching apparatus for forming a pattern, a resist coating apparatus, an exposure apparatus, and a cleaning apparatus. It is possible to reduce the generation of abnormal adhered foreign matter on a semiconductor substrate such as a wafer or a TFT substrate and to produce a semiconductor with a high yield. Moreover, in the above-described configuration, in various process processing apparatuses such as a sputtering apparatus and a CVD apparatus for forming a film on a semiconductor substrate such as a semiconductor wafer and a TFT substrate, an etching apparatus for forming a pattern, a resist coating apparatus, an exposure apparatus, and a cleaning apparatus. It is possible to provide feedback such as an alarm for the occurrence of abnormal adhered foreign matter on a semiconductor substrate such as a semiconductor wafer or a TFT substrate. By controlling process conditions such as the above conditions, exhaust conditions, temperature conditions, and applied voltage, the generation of abnormal foreign matters can be significantly reduced, and semiconductors can be produced at a high yield. Further, in the product storage apparatus for storing a large number of workpieces (semiconductor substrates) such as semiconductor wafers, TFT substrates, etc., it is possible to check the state of foreign matter adhering to a large number of workpieces and discharge the workpieces. It is possible to prevent the subsequent process from being continued on the workpiece to which foreign matter has adhered, and as a result, it is possible to produce a semiconductor with a high yield.
[0029]
【Example】
Embodiments of the present invention will be specifically described with reference to the drawings.
[0030]
[First embodiment]
First, a first embodiment will be described with reference to FIGS.
[0031]
As a typical process processing apparatus, a CVD apparatus for forming a thin film such as an insulating film on the work 4, a sputtering apparatus for forming a metal thin film or the like on the work 4, and a formed metal thin film There is an etching processing apparatus that forms a circuit pattern by performing an etching process on the like. FIG. 1 is a schematic diagram in which a foreign substance inspection apparatus is mounted in the process processing apparatus. This apparatus has one or a plurality of process processing chambers 7, work supply stations (supply station (loader) 8a, recovery stations (unloader)) 8a and 8b, such as those equipped with a loader or unloader, and a detection head 1a, A scanning stage 1b and a θ stage 3 mounted with a workpiece 4 and rotationally positioned (rotation corrected) at least in the rotation Θ direction (note that the θ stage 3 electrically rotationally corrects an image signal detected by a linear image sensor. It is not always necessary.) And a foreign substance inspection apparatus 1 having a data processing unit (CPU) 9 and an inspection control apparatus 11 for driving and controlling the scanning stage 1b and the Θ stage 3 is installed. It is composed. Before the workpiece (wafer) 4 is transferred from the workpiece supply stations 8a and 8b to the process processing chamber 7 via the buffer chamber 6 by the robot mechanism 5, the foreign matter inspection apparatus 1 attaches foreign matter or the like to the workpiece 4. The workpiece 4 is transferred to the process processing chamber 7 via the buffer chamber 6 by the handling robot mechanism 5. At this time, the data processing unit (CPU) 9 of the foreign matter inspection apparatus 1 calculates the measurement result of the foreign matter and the like, and if the value exceeds the management standard value Mp, the process processing in the process processing chamber 7 is performed. In order to avoid this, it is also possible to take a method such as sending an alarm signal to the control device 10 that controls the process processing device to control the robot mechanism 5 that handles it and returning it to the work supply stations 8a and 8b. By doing so, it is possible to reduce the creation of work defects in the process processing chamber 7, and to improve the operating rate of the process processing apparatus. On the other hand, the work 4 transferred to the process processing chamber 7 is subjected to film formation processing or etching processing in the process processing chamber 7. Next, when the processed workpiece 4 is returned to the workpiece supply stations 8a and 8b by the handling robot mechanism 5, the workpiece 4 after the process is measured by the foreign substance inspection apparatus 1 to measure the adhesion state of foreign matters and the like to the workpiece 4. After that, the robot mechanism 5 handling the workpiece 4 is stored in the workpiece supply stations 8a and 8b. At this time, the result of the measured adhesion state of foreign matter or the like on the workpiece 4 is processed by the CPU 9a or the like of the data processing unit 9 shown in FIG. 2 and stored as a database in the memory 9b or a hard disk (not shown). Then, the CPU 9a of the data processing unit 9 performs processing that indicates the adhesion state of foreign matter or the like on the work before being supplied to the process processing chamber 7 stored in the memory 9b or hard disk (not shown) as a database (before process processing). Pre-foreign matter map (shown in FIG. 5 (a)) and treated foreign matter map (shown in FIG. 5 (a)) showing the adhesion state of foreign matter etc. on the workpiece when processed and discharged (after process processing) 5 (b))), and an increased foreign matter map obtained by performing processing for comparing the number of foreign matter or the foreign matter detection position and showing the adhesion state of foreign matter on the workpiece in the process processing in the process processing chamber 7. (Shown in FIG. 5C) (the increased number of foreign substances and their positions) are displayed on the monitor 9e or the printer 9f. An example of the display is shown in FIG. In FIG. 5, the difference between the processed foreign matter map shown in FIG. 5 (a) and the foreign matter map before processing shown in FIG. 5 (b) is taken and processed as shown in FIG. (A) The number and position of increased foreign matter. (The difference between the post-processing foreign matter map and the pre-processing foreign matter map is described in Japanese Patent Application Laid-Open No. 2-170279.) The distribution (map) of the foreign matter including the number and size (for example, three levels of large, medium and small) of the adhered foreign matter is calculated by the CPU 9a of the data processing unit 9 and stored in the memory 9b or a hard disk (not shown). Can be obtained.
[0032]
As an example of the detection head 1a, there is a configuration shown in FIGS. 3A and 3B as described in Japanese Patent Laid-Open No. 5-218163. That is, as shown in an enlarged view in FIG. 3B, the illumination optical system 31 includes a semiconductor laser 32 that outputs laser light with high brightness (high intensity) and a beam of laser light output from the semiconductor laser 32. A beam diameter expanding optical system 33 that expands the diameter, a uniaxial condensing lens (cylindrical lens) 34 that condenses the laser beam expanded by the beam diameter expanding optical system 33 in a straight line (slit shape), and the uniaxial A mirror 35 that reflects the laser beam condensed by the direction condensing lens 34 and irradiates the workpiece 4 in a straight line (slit shape), and has a shallow angle with respect to the surface of the workpiece 4. It is comprised so that it may irradiate with. Although the light is condensed linearly (slit) by the uniaxial condenser lens 34, it is possible to irradiate laser light linearly (slit) with a scanning optical system such as a galvanometer mirror. Since it is necessary to scan at high speed with a scanning optical system, the optical system becomes complicated, but a beam diameter expanding optical system is unnecessary, and a semiconductor laser that outputs laser light with high brightness (high intensity) can be used. The detection optical system 36 has a wide field of view (high NA (numerical aperture) such as 0.4 to 0.6) that collects scattered reflected light generated from the surface of the work 4 by the irradiated linear laser light. A circuit existing on the surface of the workpiece 4, which includes a telecentric optical system 37, 38, a variable spatial filter 39 disposed substantially in the Fourier transform plane of the telecentric optical system 37, 38, and a linear image sensor 40. The variable reflection filter 39 shields the scattered reflected light or the spatial frequency of the repetitive circuit pattern from the edge of the pattern, and the linear image sensor 40 receives the scattered reflected light from the foreign matter. Upward is the scanning stay in the uniaxial direction (x-axis direction) of the workpiece 4 or the detection head 1a under the control of the control device 11. As shown in FIG. 3A, the detection head 1a has the illumination optical system 31 and the detection optical system 36 so that the adhesion state of foreign matter or the like can be inspected on almost the entire surface of the workpiece 4 by scanning with 1b. 6 are arranged in a staggered manner, and therefore, when the workpiece 4 or the detection head 1a is scanned once relatively in one axial direction (x-axis direction), FIG. As shown to (a), the adhesion state of a foreign material etc. can be test | inspected over the whole surface of the workpiece | work 4. FIG.
[0033]
On the other hand, as the detection head 1a, three pairs of the illumination optical system 31 and the detection optical system 36 are arranged and configured so that the workpiece 4 or the detection head 1a is relatively uniaxially (x-axis). When the scanning is performed once in the direction (direction), there is a region that is not inspected as shown in FIG. 4B, but the adhesion state of foreign matter or the like can be inspected in a substantial region on the workpiece 4. According to this, the detection head 1a can be simplified, and the detection head can be scanned at high speed.
In addition, as the detection head 1a, two pairs of the illumination optical system 31 and the detection optical system 36 are arranged and configured, and the workpiece 4 or the detection head 1a is controlled by the control from the control device 11. If scanning is performed three times in one axial direction (x-axis direction) while relatively shifting in the y-axis direction, the adhesion state of foreign matter or the like can be inspected over the entire surface of the workpiece 4 as shown in FIG. . However, in this case, it is necessary to scan the work 4 or the detection head 1a three times in the x-axis direction while relatively shifting in the y-axis direction, and the number of detection head sets can be greatly reduced. The mechanism becomes complicated, and more inspection time is required.
[0034]
In FIG. 2, a large number of foreign substance inspection apparatuses 1 and process processing apparatus control devices (information such as process gas flow rate, process gas pressure, workpiece (wafer) temperature, voltage applied to the workpiece, etc.) are also input. Are connected, and a scanning electron microscope (SEM) 21a, a secondary ion mass spectrometer (SIMS) 21b, and a scanning tunneling microscope (STM) 21c are connected to an inspection device 22 including a foreign matter inspection device 22a and a pattern inspection device 22b. 1 shows an overall system configuration composed of a foreign matter data analysis computer 20 and the like by an analysis device 21 composed of a spectroscopic device (STS) 21d and the like. The foreign matter data analysis computer 20 includes a CPU 20a having a memory 20b, a keyboard 20c and a mouse 20d for inputting data, a foreign matter analysis result, an abnormal process apparatus name that must display an alarm, an abnormal start lot, and a wafer. Display device 20e, foreign matter analysis result, abnormal process device name for which an alarm must be displayed, output device 20f such as a printer for outputting an abnormal start lot or start wafer, and start in each process processing device The external storage device (hard disk) 20g stores the correlation between the occurrence state of foreign matter and the estimated or confirmed cause of occurrence of foreign matter on a lot basis or on a start wafer basis. The foreign matter data analysis computer 20 receives data from a large number of foreign matter inspection apparatuses 1 and the control device 10 of the process processing apparatus in which the inspection devices are installed, and starts a lot that exceeds the foreign matter management values Mp and Mq. As a result, the result of detailed analysis of the start wafer and the start wafer by the inspection device 22 or the analysis device 21 and the estimated cause of failure (input by the input means 20c) are input, and the start lot unit or start time in each process processing device is input. Correlation between the occurrence state of foreign matter and the estimated or confirmed cause of foreign matter for each wafer is stored in an external storage device (hard disk) 20g.
[0035]
[Second Embodiment]
Next, a second embodiment will be described with reference to FIGS. 6, 1 and 2. FIG.
FIG. 6 shows the relationship between the number of detected foreign matter measured on the wafer 4 and the start lot or start wafer. This figure shows, as an example, a film forming apparatus, particularly a process apparatus. The film formation processing apparatus uses monosilane gas (SiH_Four), Phosphine gas (PH_Three) Or the like is introduced into the processing chamber, and a film is formed on the wafer by a chemical reaction. The chemically reacted product also adheres to the wall surface in the processing chamber, and the adhered matter is peeled off with the passage of time. For this reason, periodic plasma cleaning or the like is performed depending on the number of processed sheets.
[0036]
However, if plasma cleaning or the like is performed, the product cannot be started and the product start capability is reduced. Therefore, in order to improve the product start capability, for example, the foreign substance adhering to the wafer is almost always detected by the detection head 1a of the foreign substance inspection apparatus 1 shown in FIG. 1, and the CPU 9a of the data processing unit 9 shown in FIG. By managing the number of adhered foreign substances in units of 20 wafers) or starting wafer units, it is possible to continue the product construction even if it exceeds the normal cleaning cycle if the adhered foreign substances on the wafer are within the control value Mp. It is. In addition, the CPU 9a of the data processing unit 9 manages the number of foreign particles attached to the start lot unit or start wafer unit, and even if the attached foreign matter on the wafer is within the control value Mp, the CPU 9a continues in the start lot unit or start wafer unit. If there is an increasing trend, an alarm is directly issued to the display device 9e or the like or the control device 10 that controls the process processing device, and instructions such as cleaning in the process processing device can be given. On the other hand, the CPU 9a of the data processing unit 9 manages the number of foreign particles attached to the start lot (for example, 20 wafers) or wafer unit, and if the amount of foreign particles attached to the wafer exceeds the management value Mp, the display device at that time 9e or the like or an alarm is directly issued to the control device 10 that controls the process processing apparatus, and an instruction for cleaning or the like in the process processing apparatus is issued. In this way, in the case of a truly abnormal condition, the process processing device is cleaned and the like, and even if there are no abnormalities in the past, regular cleaning has been carried out and the operating rate of the processing device has been reduced. It becomes possible to up.
[0037]
In the above-described embodiment, the case where the data processing unit 9 of the foreign matter inspection apparatus 1 manages the number of attached foreign matters in units of start lots or start wafers has been described, but the foreign matter data analysis computer 20 in which a plurality of foreign matter inspection devices are connected. , The number of adhered foreign substances is managed in units of lots or wafers based on the adhesion status of the foreign substances generated on the wafer obtained from the data processing section 9 of the foreign substance inspection apparatus 1, and an alarm is processed in the data processing section of the foreign substance inspection apparatus 1. 9 or directly to the control device 10 that controls the process processing device.
[0038]
[Third embodiment]
Next, a third embodiment will be described with reference to FIG. 7, FIG. 1, and FIG.
For example, FIG. 7 shows the relationship between the number of detected foreign matters (maximum value, minimum value, and average value in wafer units) measured on the wafer (work) 4 and the start lot unit in the foreign matter inspection apparatus 1 shown in FIGS. Shown in FIG. 7 shows, as an example, a film forming apparatus similar to FIG. In normal management performed by the CPU 9a of the data processing unit 9 of the foreign matter inspection apparatus 1, if the maximum number of foreign matter detected on the wafer is within the foreign matter management value Mq in the start lot (for example, 25 wafers), the measured start Lot wafers are discharged from the loader 8a or unloader 8b of the film forming apparatus to the next process and started. Further, in the normal management performed by the CPU 9a of the data processing unit 9 of the foreign matter inspection apparatus 1, when the maximum number of foreign matter detected on the wafer exceeds the foreign matter management value Mq, film formation is performed on the measured start lot or start wafer. A judgment is made as to whether foreign matter or the like taken out from the loader 8a or unloader 8b of the processing apparatus and manually attached affects the yield. If there is no problem, the process proceeds from the loader 8a or unloader 8b of the film forming apparatus to the next process. Pay out. Here, regarding the troubled lot or wafer, the foreign matter data analysis computer 20 performs a failure analysis based on the relationship information between the occurrence state of the foreign matter and the cause of the failure stored in the hard disk 20g, and the foreign matter is attached. Investigate the cause and implement countermeasures for the film forming equipment. However, in normal management performed by the CPU 9a of the data processing unit 9 of the foreign substance inspection apparatus 1, even if the maximum number of detected foreign substances or the average number of detected foreign substances is within the foreign substance management value Mq, the upper limit in the foreign substance management value Mq When the limit is continuously increasing or gradually increasing in units of start lots, the foreign matter management value is set in multiple stages even within the foreign matter management value Mq, and several consecutive lots or several wafers are set. Is continued, the data processing unit 9 of the foreign substance inspection apparatus 1 generates an alarm directly to the display device 9e or the control device 10 that controls the process processing device.
[0039]
[Fourth embodiment]
Next, a fourth embodiment will be described with reference to FIG. 8, FIG. 1 and FIG.
FIG. 8 shows a system for measuring a workpiece (wafer) 4 with the foreign substance inspection apparatus 1 shown in FIG. 1 and analyzing an abnormal workpiece by comparing with a past case. This system includes a foreign matter inspection apparatus 1 and a foreign matter data analysis computer (workstation: W / S) 20 including a database 20g. The workpiece (wafer) is measured by the foreign object inspection apparatus 1, data (foreign matter map, number of detected foreign matter) is registered in the database 20g for the abnormal work, and the failure cause is analyzed for the abnormal work after that. The countermeasure contents are additionally registered in the data such as the foreign matter map registered in the database 20g of the foreign matter data analysis computer 20 using the input means 9c of the data processing unit 9 or the input means 20c of the foreign matter data analysis computer 20. In this way, data for abnormal workpieces is registered in the database 20g each time. If the workpiece (wafer) 4 to be measured next based on the accumulated data has an abnormality exceeding the abnormality management values Mp and Mq, the distribution of the abnormality map is shown as a past analysis example (data (1) is a foreign object Compared with the band distribution at the center of the wafer, the data (2) is a foreign object distributed at one location on the left edge of the wafer, and the data (N) is a foreign material distributed at four locations around the wafer). If there is something similar to the past analysis case (previous mode), the countermeasure content (the cause of failure and the countermeasure content are registered in the database in correspondence with the past analysis case (foreign substance distribution).) Are displayed on the display means 20e, output to the output device 20f, or fed back to the control device 10 of the process processing apparatus. The distribution of the foreign matter on the wafer 4 is as follows. The foreign matter aggregate is separated so as to be surrounded by a circle of radius r or a rectangle (rectangle) of each side a × b, and from the center of the wafer to the center of gravity position of the foreign matter aggregate. The distance and the size of the two-dimensional spread around the center of gravity (for example, the radius r of the circle when it can be surrounded by a circle, the length of each side when it can be surrounded by a rectangle) Half a / 2 × b / 2). It becomes possible to make the cause of the defect and the countermeasure content correspond to the aggregate of foreign matters in the lot unit or wafer unit thus classified.
[0040]
[Fifth embodiment]
Next, a fifth embodiment will be described with reference to FIG. 9, FIG. 1 and FIG.
9A and 9B are schematic diagrams for managing the apparatus state of the process processing apparatus.
That is, the process processing apparatus 91 shown in FIG. 9A includes a gas flow rate measuring unit 94 that measures the flow rate of gas supplied from the gas source 93 to the inside of the processing chamber 92, and the gas pressure or degree of vacuum inside the processing chamber 92. A gas pressure measuring unit 95 for measuring the emissivity based on the amount of radiation generated from a wafer of a known temperature in advance, the emissivity measured by the emissivity measuring unit 96 and the in-process emissivity A wafer actual temperature measuring unit 97 for measuring the actual wafer temperature based on the radiation amount Q generated from the wafer is added, and the wafer is transferred between the processing chamber 92 and the loading chamber 98 or the unloading chamber 99 inside the transfer chamber 97. This is an embodiment in which a foreign matter inspection apparatus 1 for inspecting foreign matter on a wafer 4 conveyed by an arm mechanism 5 is mounted. In general, a process processing apparatus inputs processing conditions and performs wafer processing according to the conditions. The state of the process processing apparatus during the processing, for example, the degree of vacuum or gas pressure measured by the gas pressure measurement unit 95, the gas flow rate measured by the gas flow rate measurement unit 94, and the wafer measured by the wafer actual temperature measurement unit 97 Is sent to the equipment state data collection system 97 in the control device 10, and the equipment state data collection system 97 measures the measurement results (foreign matter occurrence status, start of construction) on the wafer 4 processed at that time. When the gas pressure in the processing chamber 92 fluctuates between the end of the process processing or before and after the process processing, the total number of foreign matters measured in lot units or start wafer units) When there is a change in the flow rate of gas supplied into the processing chamber 92, or there is a change in the temperature of the wafer, a correlation with the occurrence of foreign matter is calculated, and these phases are calculated. You can accumulate data. Then, the control device 10 estimates the cause of the failure when a large amount of foreign matter is generated based on the occurrence state of the foreign matter measured in the foreign matter inspection device 1 and the accumulated correlation data, and together with the cause of the failure. An alarm can be issued. At this time, it is obvious that the cause of the defect may be estimated using data stored in the hard disk 20g of the foreign matter data analysis computer 20. Reference numeral 100 denotes a control device that performs various controls in the process processing apparatus 91 including the transfer arm mechanism 5.
[0041]
The process processing apparatus shown in FIG. 9B processes the equipment state data collection system 97 in the data processing unit 9 of the foreign substance inspection apparatus 1 so as to accumulate correlation data in the memory 9b or a hard disk (not shown). It is composed. Even in this case, the cause of the failure when a large amount of foreign matter occurs is estimated based on the occurrence state of the foreign matter measured by the foreign matter inspection apparatus 1 and the correlation data stored in the memory 9b or the hard disk (not shown). An alarm can be issued along with the cause of the failure.
[0042]
[Sixth embodiment]
Next, a sixth embodiment will be described with reference to FIG. 10, FIG. 1, FIG. 2, and FIG. That is, FIG. 10A shows an embodiment in which an on-machine foreign matter inspection device (on-machine foreign matter monitor) 1 is mounted on a process film forming apparatus. This process film forming apparatus includes a loader (L) unit 102, an unloader (U / L) unit 103, a transfer chamber 104, and a reaction chamber 101. The transfer arm mechanism 5 is provided in the transfer chamber 104 and above the transfer chamber 104. It has a detection head 1a 'for on-machine foreign matter monitoring. The wafer 4 is received from the loader unit 102 and transferred to the reaction chamber 101 by the transfer arm mechanism 5. The wafer 4 processed in the reaction chamber 101 is returned to the unloader chamber 103 by the transfer arm mechanism 5. At that time, the surface of the wafer 4 being moved by the transfer arm mechanism 5 is monitored (inspected) by the on-machine foreign matter monitoring detection head 1 a ′ mounted on the upper side of the transfer chamber 104. In this embodiment, the surface of the wafer 4 after processing is monitored, but it is also possible to monitor the surface of the wafer 4 before processing or before and after processing.
[0043]
FIG. 10B shows a cross section of the detection head portion 1a 'for on-machine foreign matter monitoring. The inside of the transfer chamber 104 is a vacuum atmosphere, and the wafer 4 being moved by the transfer arm 5 a of the transfer arm mechanism 5 is monitored (inspected) by the detection head 1 a ′ mounted on the upper side of the transfer chamber 104. The detection head 1 a ′ is attached on a vacuum-compatible standard flange 106 attached to the upper cover 105 of the transfer chamber 104. The detection head 1a ′ includes an illumination optical system 31, a detection optical system 36, and a wafer rotation detection system (details will be described later) 110, and the rotation of the wafer 4 is detected by the wafer rotation detection system 110 in software. The surface of the wafer 4 corrected (by image processing) and illuminated by the illumination optical system 31 is monitored (inspected) by the detection optical system 36. In addition, the illumination part 106a, the detection part 106b, and the detection part 106c of the detection head 1a 'in the vacuum-compatible standard flange 106 are made of transparent parts. The mirror 35 may be mounted on the vacuum compatible standard flange 106.
In the above embodiment, monitoring (inspection) is performed via the vacuum-compatible standard flange 106. However, the detection head main body 1a 'can be reduced in size so that it can be installed in the transfer chamber 104, that is, in a vacuum atmosphere. is there.
[0044]
[Sixth embodiment]
Next, a sixth embodiment will be described with reference to FIGS.
FIG. 11 shows a schematic diagram in which the foreign matter inspection apparatus 1 is equipped with a wafer code identification device 111 for reading the product type name, lot number, wafer number, etc. on the wafer by printing or bar code display. The wafer code identification device 111 includes an optical system (not shown) for printing and reading, and a recognition processing unit (not shown) for identifying printing. The wafer supply / dispensing station for the foreign matter inspection apparatus 1 or the measurement station of the foreign matter inspection apparatus 1 is provided with a wafer code identification code and printed on the wafer 4 as shown in FIG. The characters No and Wafer No are identified. On the other hand, the foreign matter or the like is measured on the same wafer 4 by the foreign matter inspection apparatus 1. The print data of the wafer and the measurement data of the foreign matter are transferred together to the data management system (data processing unit) 9. In this way, management can be performed in wafer units in addition to lot units in which how much foreign matter or the like is attached to which wafer 4. These data may be stored in the hard disk 20g or the like in the foreign matter data analysis computer 20, managed by the foreign matter data analysis computer 20, and fed back to the control device 10 of each of the process processing apparatuses A to N.
Further, even when there are a plurality of the same process processing apparatuses, the unit of the process processing apparatuses A to N can be obtained by inputting which process processing apparatus A to N the wafer is started by the inspection condition instruction on the foreign substance inspection apparatus 1 side. Can manage. For this reason, for example, the manufacturing apparatus (process processing apparatus) A has few foreign substances and the like, but for example, the manufacturing apparatus B has a large number of foreign substances and so on. Therefore, the data management system (data processing unit) 9 narrows down abnormal process apparatuses. Easy to do.
[0045]
[Seventh embodiment]
Next, a seventh embodiment will be described with reference to FIGS.
FIG. 13 shows a schematic diagram in which the foreign matter inspection apparatus 1 is mounted on a wafer stocker 131 that stores a large number of wafer cassettes 132. The configuration of this apparatus includes a wafer stocker 131, a wafer cassette transfer robot 133, a storage shelf 134, a foreign matter inspection apparatus 1, a data management system 9, and the like.
The wafer cassette (which may include a cassette case) 132 is loaded and unloaded from the wafer case take-out entrance 135. The wafer cassette 132 containing the wafers stored in the wafer stocker 131 is placed on the storage shelf 134. A plurality of wafer cassettes 132 stored in the wafer stocker 131 are transferred to the side of the foreign substance inspection apparatus 1 by the wafer cassette transfer robot 133 before being delivered. Therefore, the wafer 4 stored in the wafer cassette 132 is taken out by a wafer handling mechanism (not shown) (not shown) installed in the foreign substance inspection apparatus 1 (measuring a mechanism similar to 5), and foreign matters on the wafer 4 are measured. To do. These measured results are processed by a data management system (data processing unit) 9 and stored in a memory 9b or a hard disk (not shown). Further, these data can be stored in the hard disk 20g or the like in the foreign matter data analysis computer 20.
[0046]
On the other hand, as shown in FIG. 14, when the wafer cassette 132 is accommodated in the wafer case 136, the cassette case upper lid 136a is hooked by the case hook 137, and the storage shelf 134 is lowered to move to the cassette case lower lid 136b. On the other hand, the cassette case upper lid 136a is opened. Next, the wafer cassette carrying robot 133 takes out the wafer cassette 132 storing a large number of wafers 4 in the cassette case lower lid 136 b and places it on the side of the foreign matter inspection apparatus 1. Thereafter, foreign matter and the like are measured in the same manner as described above.
The data management system (data processing unit) 9 performs management of entering / exiting of the wafer cassette 132 and management of measurement results of foreign matters and the like. As described above, for the wafer 4 that is not measured after the process processing, the foreign matter and the like are measured when the wafer 4 is stored in the wafer stocker 131, so that the product start time can be performed without delay and the time can be shortened. In addition, for a product (wafer) to which foreign matter or the like is frequently attached, the data management system (data processing unit) 9 can control the delivery to the next process in the wafer stocker 131, thereby preventing the creation of defects. it can.
[0047]
[Eighth embodiment]
Next, an eighth embodiment will be described with reference to FIGS.
The wafer rotation correction will be described. That is, a wafer rotation direction detector 110 (shown in FIG. 10) is provided immediately before the foreign matter detection optical systems (detection heads) 1a and 1a 'shown in FIGS. The wafer rotation amount obtained by the wafer rotation direction detector 110 is obtained when the wafer rotation stage (Θ stage) 3 is provided, or when the hand of the robot mechanism 5 for handling the wafer has a rotation mechanism, or the foreign matter detection optical system. When the (detection head) 1a rotates, it is mechanically corrected thereby. When there is no rotation correction mechanism, rotation correction is performed by an electric circuit or software processing. In the case of rotation correction by an electric circuit or software processing, a rotation correction mechanism by a Θ stage or a robot mechanism hand or a foreign matter detection optical system is not required, and therefore the mechanism can be simplified and miniaturized. At the same time, it is possible to easily cope with changes in the dimensions of the wafer.
First, in order to detect the rotation direction of the wafer,
(1) The orientation flat direction of the wafer is detected.
(2) The circuit pattern direction of the wafer is detected.
(1) Diffracted light detection
(2) Circuit pattern image detection (feature extraction)
Strictly speaking, since the circuit pattern direction and the orientation flat direction are deviated, when it is necessary to accurately detect the direction of the circuit pattern, the direction of the circuit pattern must be detected.
[0048]
The wafer 4 passes under the wafer rotation direction detector 110 or detects the rotation direction of the wafer when temporarily stopped.
(1) A method for detecting the orientation flat direction of the wafer will be specifically described.
A detection method of the first wafer rotation direction detector 110a will be described with reference to FIG. That is, the wafer 4 passes under the illumination system having several light emitting points 152 along the wafer moving direction V and moves from the position 153 to the position 154. The locus 155 on the wafer 4 of the illumination light emitted from the light emitting point 152 of the illumination system of the wafer rotation direction detector 151 is shown. In the case of the light emission point A, the time As when the illumination light starts to hit the wafer 4 and the time Ae when the wafer 4 is removed are measured, and this is also performed for the other light emission points B to G. The direction of the orientation flat 156 of the wafer 4 is obtained from the above data and the moving time of the wafer 4, and the rotational deviation amount θ1 of the wafer 4 is calculated. As a method for detecting the rotation direction of the wafer 4, there are scribe area detection, chip detection, and special mark detection such as alignment marks.
[0049]
The detection method of the second wafer rotation direction detector 110b and the third wafer rotation direction detector 110c will be described with reference to FIG.
That is, the second wafer rotation direction detector 110b, as shown in (b), reflects the reflected light reflected from the contour including the illumination light source 162 that illuminates linearly and the orientation flat edge of the wafer 4 that is illuminated linearly. The direction of the orientation flat edge 156 (rotation deviation amount θ2 of the wafer 4) is obtained on the basis of the reflected image signal detected by the sensor 163, as in FIG. Can do. Here, in the case of detecting reflected light in this way, in addition to detecting the orientation flat edge, the feature of the image of the circuit pattern (including scribe area detection, chip detection, alignment mark, etc.) on the surface of the wafer 4 is extracted. By doing so, it is also possible to calculate and detect the amount of rotational deviation of the wafer.
Further, as shown in (c), the second wafer rotation direction detector 110c includes an illumination light source 166 that linearly illuminates and a linear sensor 167 that detects light shielded by the contour including the orientation flat edge of the wafer 4. Based on the shielding light image signal detected by the sensor 167, the direction of the orientation flat edge 156 can be obtained in the same manner as in FIG.
[0050]
(2) A method for detecting the circuit pattern direction of the wafer will be specifically described.
First, a method for detecting the amount of wafer rotation deviation by detecting diffracted light from a circuit pattern on the wafer will be described.
FIG. 17 shows a method of detecting diffracted light from a circuit pattern on the wafer 4 by the wafer rotation direction detector 110d in order to detect the wafer rotation direction. Light emitted from an illumination light source 171 composed of a laser light source or the like is condensed by a condenser lens 172 and reflected by a mirror 173 to illuminate a circuit pattern on the wafer 4 by oblique illumination, and the diffracted light is directed upward. It detects with the objective lens 174 and the detector 175 which were provided in FIG. Here, the detector 175 is installed at the Fourier transform plane position of the objective lens 174, and the wafer 4 may be moved in a uniaxial direction or temporarily stopped. The detection images on the Fourier transform plane are shown in FIGS. FIG. 6B shows the case where the wafer is not rotated (wafer reference position), and the diffracted light (0th-order light) 177 from the main circuit pattern or the repeated circuit pattern on the wafer is centered in the detector 175 (Y-axis direction). The center of the image. FIG. 4C shows the case where the wafer is rotated, and the diffracted light (0th order light) 178 from the main circuit pattern or the repetitive circuit pattern on the wafer forms an image shifted by Δd from the center of the detector 175. This deviation amount Δd has a correlation with the wafer rotation deviation amount θ3, and the wafer rotation deviation amount θ3 can be obtained from the deviation amount Δd. That is, the CPU 176 connected to the detector 175 can calculate the shift amount Δd from the image signal based on the diffracted light detected from the detector 175, and can calculate the wafer rotation shift amount θ3 from the shift amount Δd. . Here, the light emitted from the illumination light source 171 is condensed and irradiated (projected) on the surface of the wafer 4 from an oblique direction, so that the diffracted light is sharpened as the illumination light source 171 is a point light source. Therefore, the detection accuracy of the rotational deviation amount of the wafer is increased. As the detector, a TV camera, a one-dimensional linear sensor, a position sensor, or the like can be used.
[0051]
Next, FIG. 18 shows a case where vertical illumination is used instead of the oblique illumination in FIG. 17 (wafer rotation) as a method of detecting diffracted light from the circuit pattern on the wafer in order to detect the wafer rotation deviation amount. A direction detector 110e) is shown. That is, instead of the illumination light source 171, the condenser lens 172, and the mirror 173 in FIG. 17, the illumination light source 181 and the half mirror 182 are used. In this case, the size of the unit main body can be reduced as compared with FIG. 17, and all the angles (360 degrees) can be detected in the rotational deviation angle of the wafer. That is, since the circuit pattern formed on the wafer 4 mainly includes an X-direction component and a Y-direction component, as shown in (b) when there is no wafer rotation (wafer reference position). When the cross-shaped diffracted light (0th-order light) 183 forms an image in the X and Y axis directions of the detector 175 and the wafer is rotated, the diffracted light 184 is converted into the X of the detector 175 as shown in FIG. , The image is shifted from the Y-axis direction by an angle θ4. The CPU 176 connected to the detector 175 calculates the angle deviation amount θ4 from the image signal based on the cross-shaped diffracted light detected from the detector 175, and calculates the rotation deviation amount θ4 of the wafer from the angle deviation amount θ4. be able to.
[0052]
Next, in FIG. 19, as a method of detecting diffracted light from the circuit pattern on the wafer in order to detect the amount of wafer rotation deviation, the detector and lens installed above in FIG. A wafer rotation direction detector 110f) is shown. That is, instead of the detector 175 and the lens 174 in FIG. 17, the detector 192 and the lens 193 are installed in an oblique direction. The illumination optical system 194 including the illumination light source 195 and the condenser lens 196 is also arranged so that the detection optical system 191 including the detector 192 and the lens 193 is opposed to each other. In this case, when the wafer is not rotated (wafer reference position), the diffracted light (0th order light) 197 forms an image at the center of the detector 193 (center in the Y-axis direction) as shown in FIG. In the case of rotation, as shown in (c), the diffracted light 198 is imaged with the deviation Δd ′ and the angle Δθ5 shifted from the center of the detector 192 (center in the Y-axis direction). The synthesized deviation amount Δd ′ + Δθ5 has a correlation with the wafer rotational deviation amount θ5, and the wafer rotational deviation amount θ5 can be obtained from the synthesized deviation amount Δd ′ + Δθ5. That is, the CPU 176 connected to the detector 193 calculates a shift amount Δd ′ + Δθ5 synthesized from the image signal based on the diffracted light detected from the detector 192, and the rotational shift amount of the wafer from the shift amount Δd ′ + Δθ5. θ5 can be calculated.
[0053]
Next, FIG. 20 shows a method of using the circuit pattern image on the wafer by the wafer rotation direction detector 110g in order to detect the wafer rotation deviation amount. That is, a circuit pattern on the wafer 4 is illuminated by an upper illumination optical system 201 constituted by the illumination light source 202, the condenser lens 203, the mirror 204, and the half mirror 205, and the circuit on the illuminated wafer 4 is illuminated. A light image of the pattern is detected by a detection optical system 206 including an objective lens 207, an imaging lens 208, and a detector 209. When the detector 209 is a TV camera, a temporary still image of the wafer is obtained. When the detector 209 is a linear sensor, the wafer is uniaxially scanned and an optical image of a circuit pattern on the formed wafer 4 is obtained. It can be detected by imaging. The detected image is shown in FIG. The CPU 176 connected to the detector 209 can calculate the rotational deviation amount of the wafer 4 by detecting the tilt angle of the chip 210 or the direction of the scribe area 211 in the image shown in FIG.
[0054]
Next, a technique related to rotation alignment will be described.
[0055]
The object of the present application is basically a semiconductor, but may be a substrate on which a fine pattern is repeatedly formed, for example, a liquid crystal display element and a substrate in the formation process, or other patterns.
[0056]
In the foreign matter inspection apparatus of the present application, the adjacent chip comparison is an important technology. This adjacent chip comparison technology knows the corresponding point of the adjacent chip, compares the detected output signal level of the corresponding point, and if it is the same signal level, determines that there is no defect or foreign matter in any chip, and the signal level If the difference is large, it is determined that a defect or a foreign substance exists on the chip having the higher signal level.
[0057]
In this technique, it is necessary to find a corresponding point between adjacent chips as described above. Of course, any method for finding the corresponding points may be used. As an example, after all the data is acquired, the correlation function of the data is taken for the directions x and y considered to be the direction in which the chips are arranged, and the chip size p and the arrangement direction θ may be calculated from the period of the correlation function. Since this method requires a large capacity for a storage device for storing data, the following method is also conceivable. That is, it is possible to know the corresponding points between adjacent chips by fetching the chip pitch p from the design data and detecting the chip arrangement direction for each wafer. (Fig. 22)
In this method, it is necessary to know the direction of chip arrangement, that is, the direction of rotation of the wafer. As one method, the orientation of the orientation flat (orientation flat) 156 formed on the wafer 4 may be measured. This is based on the premise that the orientation of the orientation flat is used as a reference when forming the pattern. As another method, the direction θ of the chip formed on the wafer may be directly measured. However, the pattern formed on the wafer is often complicated, and it is difficult to measure the pattern formation direction from the pattern shape. Here, as shown by the wafer rotation direction detector 110e in FIG. 21, when a light beam is irradiated onto the formed pattern, diffraction occurs due to the shape of the pattern, and the diffraction pattern can be detected. Since many patterns on a wafer are often formed by repeating basic patterns having x and y directions, this diffraction pattern mainly emits in the x and y directions, in other words, as shown in FIG. Thus, the 0th-order diffracted light 184 is diffracted in the x and y directions. Therefore, by measuring the direction of the 0th-order diffracted light 184 from the detection image (diffraction image) 185, the direction θ of the pattern on the wafer 4 can be accurately known.
[0058]
The measured chip arrangement direction θ is used to know the corresponding point (coordinate relation 187 between a and a ′ shown in FIG. 23) between adjacent chips on the acquired data (wafer rotation correction 187 by electrical processing shown in FIG. 21). The image data obtained by the linear image sensor 40 (the image shown in the memory range in FIG. 24) is sequentially stored in the memory 189 for comparison. The means 190 realizes the comparative inspection (defect inspection of foreign matter or the like) by sequentially comparing these corresponding points (a and a ′, b and b ′ shown in FIG. 24). This method requires a storage capacity for temporarily storing the captured image data in the memory 189, while realizing a highly reliable system that does not require a mechanism unit.
[0059]
As another method, as shown in FIG. 26, the entire detection system 36 is rotated so that the longitudinal direction of the linear image image sensor (one-dimensional detector) 40 is parallel to the chip arrangement direction θ. Thus, it is possible to ensure that the corresponding points on the adjacent chips are on the detector 40. By this method, the capacity for temporarily storing the image data in the memory 189 to know the corresponding points can be minimized. On the contrary, since this method needs to rotate the entire detector 36, a rotation mechanism is required.
[0060]
The above method has an effect that it is possible to detect a chip arrangement method of a work (wafer) in which no orientation flat or notch is formed on the work (wafer). In addition, since this method directly measures a pattern on a workpiece (wafer), it is possible to take higher-precision measurement and higher-accuracy corresponding points than a method using an orientation flat or the like.
[0061]
Hereinafter, a specific configuration of the rotation detection unit 110 will be described with reference to FIG. 21 (the same configuration is also shown in FIG. 18). The rotation detection unit 110e includes a light source 181 that is as close to a point light source as possible, a half mirror 182, an imaging optical system 174, and a two-dimensional detector 175. The point light source 181 forms an image on the detector 175 via the half mirror 182, the imaging optical system 174, and the wafer 4. Here, the workpiece (wafer) 4 may basically be considered as a mirror.
[0062]
Here, a space between the imaging optical system 174 and the workpiece (wafer) 4 is preferably an infinite system (telecentric optical system). When this portion is configured as an infinite system, the detection result is not greatly affected even if the position of the workpiece (wafer) 4 in the optical axis direction varies slightly.
[0063]
An image (diffracted image) 185 detected by the detector 175 is shown in FIG. In many semiconductor patterns and liquid crystal display patterns, zero-order diffracted light 184 in the x and y directions as shown in the figure is detected as a cross-shaped straight line. Here, the direction of the diffracted light 184 corresponds to the direction of the chip arrangement θ on the wafer 4.
[0064]
From the image 185 detected here, the direction of a straight line forming a cross shape can be measured by the well-known Hough transform 186. What is characteristic here is that when the workpiece (wafer) 4 is placed perpendicularly or substantially perpendicular to the optical axis, the Hough transform, which is usually two-dimensional, can be compressed to one-dimensional. Next, two straight lines (1) and (2) are shown.
xsinθ₁−y cos θ₁= 0 (1)
xcosθ₂+ Ysinθ₂= 0 (2)
Where θ₂= (Π / 2) + θ₁
Θ of this line₁, Θ₂Since they are known to be orthogonal to each other, there is essentially one variable. Here, θ can be calculated by substituting the coordinates on the straight line into x and y in the above equations (1) and (2) with the center of the optical axis as the origin of the image. This θ is calculated for all points on the image, and a histogram weighted by the detection output on the image at that time is created as shown in FIG. The peak of this histogram is θ₁, Θ₂become. This is because a large signal is detected in pixels on a straight line.
[0065]
Here, in reality, in order to improve the accuracy of θ, it is necessary to make the histogram stage have a high resolution. However, if the histogram stage is set to high resolution, the value on the vertical axis becomes small, the curve is not smooth, and the accuracy when calculating the peak is lowered. Therefore, as a method for solving these trade-offs, the center-of-gravity calculation method shown in the following equation (3) is preferable. Equation (3) is θ₁The calculation formula of₂Can be calculated in the same manner.
[0066]
[Expression 1]

Note that I (x, y) represents, for example, the intensity of the 0th-order diffracted light 184 of the detection image 185 shown in FIG.
[0067]
This method uses the rotational position θ₁Or θ₂Is the range (θ₁−δ₀<Θ <θ₁+ Δ₀Or θ₂−δ₀<Θ <θ₂+ Δ₀) Must be known in advance, and the detection accuracy improves when the existence range can be predicted more accurately. Accordingly, it is necessary to align the orientation of each workpiece (wafer), that is, the chip arrangement direction θ in a certain range in advance by orientation flat alignment or the like. If there is no diffracted light of the first or higher order, a theoretically complete value can be calculated even if the addition range is 0 to 90 degrees. Therefore, it is desirable that the first-order or higher-order diffracted light intensity is small. Needless to say, two-dimensional Hough transform may be used if the calculation time does not matter.
[0068]
In the above formula, θ is calculated to obtain a histogram. However, from the viewpoint of shortening the calculation time, tan θ, sin θ, or cos θ may be calculated to obtain the histogram. If there is a slight deviation of the optical axis, θ may be calculated with an error. In the case of the method using this diffracted light, the minute deviation of the optical axis is specifically the phenomenon of the peak break in the histogram (shown in FIG. 27C). This is because, as shown in FIG. 27B, in the case of the diffraction pattern 184, there are angles on the + side and the − side that have an error that is calculated in the case of misalignment with respect to the true straight line direction θ. To occur. Therefore, as described above, when calculating the center of gravity, the deviation of the optical axis is cancelled. Also in this sense, the method for obtaining the center of gravity based on the equation (3) can be expected to calculate with high accuracy.
[0069]
The above method using the one-dimensional Hough transform can be applied even when the center of the optical axis is not on the detected image. Specifically, the center of the optical axis existing outside the image may be expressed in the same coordinate system as the image.
In this method using diffracted light, the detection signal output at the center of the optical axis is often extremely large, and the output of the detector is often saturated over a wide range around the center of the optical axis on the image. Therefore, in many cases, the detection accuracy is improved by masking an appropriate range at the center of the optical axis and not using it in the calculation of θ. This mask may be a light shielding plate installed on the optical system, or a software s mask that does not use data at the center of the detected signal.
Actually, as shown in a detection image 185 in FIG. 21, a ± first-order or ± second-order diffraction pattern 192 is formed and detected. However, since these patterns 192 are usually weaker than the 0th-order diffracted light 184, they can be ignored by the following method. The first is a method of binarization using a threshold value, and the second is a method of using multivalued data. Although the case where the detector is two-dimensional has been described, a rotation detection system can be realized as follows even if a one-dimensional detector is used.
[0070]
That is, the wafer rotation deviation can be corrected by the processing apparatus shown in FIG. The processing device (correction device) includes a rotation detection optical system 110e (detector 175), a rotation detection calculation system 186, an adjacent chip corresponding point vector calculation system (coordinate relationship between a and a ′) 187, and a memory for storing image data. 189 and comparison means 190. In the rotation detection calculation system 186, the direction θ of the chip arrangement is calculated by the method described above. An adjacent chip correspondence vector is calculated from this θ and data of the chip pitch p input from the design data. In the chip comparison means 190, corresponding points (a and a ′, b and b ′ shown in FIG. 24) are extracted from the memory information stored in the memory 189 by the adjacent chip corresponding vector in the longitudinal direction of the linear image sensor 40, and the signal The outputs are compared, and a foreign object signal 188 due to mismatch is detected. Here, the field of view needs to be larger than twice the chip pitch. Further, when the allowable tilt of the workpiece (wafer) (the allowable tilt range of the workpiece for performing the foreign substance inspection) is θ, the memory range l stored in the memory 189 is sinθ in the visual field size of the linear image sensor 40. A capacity capable of recording the range of the length multiplied by is required.
[0071]
Next, rotation correction in the workpiece scanning direction comparison method will be described with reference to FIG. That is, the case where the adjacent chip to be compared is in the longitudinal direction of the linear image sensor 40 as shown in FIG. 24A has been described, but the comparison target chip is not necessarily in the longitudinal direction of the linear image sensor 40. As will be described below, the direction may be a direction perpendicular to the longitudinal direction of the linear image sensor 40, that is, the workpiece scanning direction. Similar to the comparison in the longitudinal direction of the linear image sensor 40, the corresponding point of the adjacent chip can be obtained by calculating the adjacent chip corresponding vector in the direction perpendicular to the longitudinal direction of the linear image sensor 40. The memory size (memory range l) can also be calculated by the same calculation.
[0072]
In this case, even if the detection field of view does not have a sufficiently large value with respect to the chip size, chip comparison can be realized, but on the other hand, the workpiece feeding accuracy by the handling mechanism or the like is increased and the adjacent in the scanning direction is present. It is necessary to know the corresponding points of the chip accurately. Further, in this comparison of scanning directions, when θ is close to 0 degrees, there is an effect that the influence of illumination unevenness, detection lens unevenness, and the like is eliminated.
[0073]
Next, rotation correction by the rotation alignment mechanism will be described with reference to FIGS. That is, for the rotation correction by the processing device using the memory, the entire optical system 36 (the illumination system 31 and the rotation) based on the chip arrangement direction θ (shown in FIG. 26) calculated by the rotation detection calculation system 186. The detection optical system 110 may also be used together.) By rotating the work (wafer), it is possible to simplify the calculation of the corresponding points of the adjacent chips. Then, in the chip comparison means 191, the corresponding points are extracted from the memory information stored in the memory 189, the signal outputs are compared, and the foreign object signal 188 due to the mismatch is detected. Further, as an effect of this method, it is possible to cope with a case where the accuracy of the mechanism for scanning the workpiece (wafer) (unevenness of feed rate, vibration in the optical axis direction, vibration in the scanning direction detector direction, etc.) is poor. Further, by using the rotation alignment mechanism in this way, it is not necessary to make the scanning direction and the chip arrangement direction perpendicular to each other. Further, when the spatial filter 39 is used, the angle of the spatial filter 39 accurately matches the chip arrangement, so that the effect of the spatial filter 39 can be maximized.
[0074]
Next, the 0th-order cut space filter system + chip comparison will be described. That is, when the chip comparison method is used, it may not always be necessary to use the spatial filter 39 that shields the nth-order diffracted light. In particular, when the minimum cell size of the chip pattern formed on the wafer 4 is reduced and the first-order or higher-order diffracted light does not enter the detection lens 37, only the zero-order light may be shielded. In this case, there is an advantage that it is not necessary to cope with the warp of the wafer 4 and to cope with the inclination of the wafer 4 which are necessary when using the spatial filter 39. FIG. 28 and FIG. 29 show the state of the diffracted light and the opening of the detection lens when the chip arrangement direction on the wafer is as shown in FIG. 28 assumes an incident angle α of illumination and a prospective angle γ of the detection lens 37, and assumes a certain spherical surface 282. FIG. 29 shows intersection lines 284 of the spherical surface 282, the intersection of illumination 283, and the prospective angle of the detection lens 37. . Reference numeral 283 denotes an incident point on the spherical surface 282, and reference numeral 285 denotes an outgoing point on the spherical surface 282. Here, the main pattern information on the wafer 4 can be erased by rotating the wafer 4 in the θ direction so that the 0th-order diffracted light does not enter the detection lens 37. Thereby, it is possible to emphasize and detect the foreign matter or the defect attached on the pattern in the wafer 4. If the above chip comparison is performed after detection in this way, the above foreign matter and defect can be detected. The expression for the condition under which the detection optical system 38 escapes the pattern rotates the wafer 4 relatively up to x0 obtained by the following expression (4). That is, the wafer 4 is relatively rotated by x0−θ.
sin α · sin (x0)> sin γ (4)
At this time, the maximum value x0 (max) of the rotation angle x0 is obtained by the relationship of the following equation (5) from the above equation (4).
sin (x0 (max)) = sinγ / sinα (5)
That is, it is sufficient if the relative rotation stroke between the wafer 4 and the detection optical system 36 including the detector 40 is selected so as to realize the above x0 (max). Specifically, the numerical aperture (NA = sin γ) of the objective lens 37 of the detection optical system 36 is about 0.1 (focal length f = about 70 mm (transparent from the outside of the transfer chamber 104 as shown in FIG. 10B). This is because a focal length f of about 50 mm or more is required to detect foreign matter on the workpiece (wafer) 4 through the transparent window 106), and the focal depth is about ± 60 μm (the workpiece (without automatic focusing) In order to detect foreign matter on the wafer 4, a depth of focus of about ± 40 μm to ± 30 μm is necessary.) When α is 60 degrees, x0 (max) is about 6.6 degrees, and the detection optical system When the numerical aperture (NA = sin γ) of the 36 objective lens 37 is about 0.08 (focal length f = about 90 mm, depth of focus is about ± 60 μm) and α is 85 degrees, x0 (max) is about 4. 6 degrees, x0 (max), that is It is sufficient if a rotation allowable range of about 5 to 10 degrees can be realized as a counter rotation stroke.If the workpiece (wafer) 4 is transported under the condition of θ> x0 (max) with θ, the workpiece Obviously, it is not necessary to rotate the (wafer) 4 or the detection optical system 36.
[0075]
The above method eliminates the need to install the zero-order cut filter 39 in the detection optical system 36, and thus has an effect that the imaging performance of the detection optical system 36 is not deteriorated.
[0076]
Here, it is only necessary to block the above-described 0th-order diffracted light, so the rotation angle θ of the wafer 4 may be set to 0 degrees. In this case, the 0th-order cut filter 39 shown in FIGS. 3 and 31 is required. In this case, the 0th-order cut filter 39 is experimentally required to have a wider width, specifically, to sufficiently shield the 0th-order diffracted light. In this case, as described above, the rotation of the wafer 4 is detected, the rotation correction is performed to calculate the chip arrangement vector, and the chip comparison is realized, and the method of not performing the wafer rotation detection and performing the chip comparison Can be considered. However, the method of performing chip comparison has lower detection sensitivity or the like than the method of not performing the comparison. In particular, the pattern formed on the wafer 4 has various directional components such as round corners and cannot be completely removed by the zero-order cut filter 39. Accordingly, by comparing the chips, those that cannot be erased by the 0th-order cut filter 39 can be removed.
[0077]
[Ninth embodiment]
Next, installation of the inspection unit (consisting of the detection head 1a, the handling mechanism 5, etc.) will be described. That is, the inspection unit described above is a process apparatus (shown in FIGS. 1, 9 and 10) with predetermined specifications, a wafer transfer system 5 (shown in FIGS. 1, 9 and 10), and a wafer stocker unit. 131 (shown in FIG. 13) or the like. At the time of inspection, the inspection surface of the workpiece (wafer) 4 is allowed to pass within the range of the focal depth of the detection optical system 36 constituting the inspection unit (detection head 1a). That is, at this time, the inspection surface of the workpiece (wafer) 4 may be passed within the range of the focal depth. Further, depending on the handling mechanism such as a stage on which the workpiece (wafer) 4 is placed or a transfer arm, the warp of the wafer may not be absorbed. In such a case, automatic focusing or automatic tilt adjustment described later is required. . Even in this case, the curvature of the wafer warp is not at a problem level.
[0078]
Next, the arm 5a in the handling mechanism 5 for transporting the workpiece (wafer) 4 will be described with reference to FIG. As described above, the inspection surface of the workpiece (wafer) 4 needs to be within the range of the focal depth of the detection optical system 36 of the inspection unit (detection head) 1a. Therefore, it is necessary to suck the work (wafer) 4 on a flat stage or arm. Since vacuum suction cannot be performed in a vacuum, an electrostatic suction type suction method is desirable. For example, an example of an electrostatic adsorption type transfer arm is shown in FIGS. An example of the configuration of the electric circuit 333 (shown in FIG. 33B) of the electrostatic adsorption arm 331 (5a) is shown. The warp of the wafer 4 needs to be adjusted to about ± 10 μm.
[0079]
FIG. 33B shows a cross section of the electrostatic chuck 332. A pair of electrodes 333 are arranged, and a high voltage 335 is applied to two poles. At the start of suction, the switching circuit 336 is controlled based on the switching signal 337 to apply a voltage from the high voltage 335, and at the time of suction removal, the switching circuit 336 is controlled based on the switching signal 337 to short-circuit the two stations. This stage is only used as the arm 5a of the above-described transfer robot (handling mechanism) 5 for transferring the work (wafer) 4 and eliminates warping of the work (wafer) 4. . Therefore, it is thin enough to pull out the workpiece (wafer) 4 from the loader or unloader (wafer cassette) 8a, 8b, and has a thickness sufficient to correct warpage of the workpiece (wafer) 4. Specifically, a ceramic having a thickness of about 2 mm to 6 mm is preferable. Also, the size must be sufficient to correct the warp of the workpiece (wafer) 4. Specifically, a shape having a radius of 60% to 100% of the radius of the workpiece (wafer) 4 is preferable. Of course, the shape does not have to be a disk shape, and may be another shape such as a rectangle or a triangle.
FIGS. 33C and 33D show a cross section of the transfer arm 321 in the atmosphere. The transfer arm 321 is provided with a vacuum suction groove 322 connected to a hole 323 communicating with an exhaust passage 324 connected to a vacuum source (not shown) so that the workpiece (wafer) 4 can be vacuum-sucked. Has been. Thus, in the atmosphere, the vacuum suction method shown by 321 in FIGS. 33 (c) and 33 (d) can be used in the transfer arm 5a. Therefore, the vacuum suction method is preferable. Of course, electrostatic adsorption may be used as described above. Other shapes, thicknesses, materials, etc. are basically the same as those of the electrostatic adsorption type described above.
It goes without saying that such a transfer arm 5a should be used not only for foreign object inspection but also for other uses where warping of the workpiece (wafer) 4 becomes a problem. That is, the transfer arm 5a of the handling mechanism (transfer robot) 5 includes a process apparatus (shown in FIGS. 1, 9 and 10), a wafer transfer system 5 (shown in FIGS. 1, 9 and 10), and the like. It is installed in a wafer stocker unit 131 (shown in FIG. 13) or the like and is used for transporting a workpiece (wafer) 4.
[0080]
Next, an apparatus for warping a workpiece (wafer) will be described with reference to FIGS. The foreign matter inspection apparatus 1 according to the present invention is problematic in two respects when the workpiece (wafer) 4 is warped. One is a change in the focal position of the detection optical system (objective lens 37) 36 due to warping. For example, as shown in FIG. 34A, when there is a warp having a shape such that the center of the 8-inch wafer 4 swells by 400 μm with respect to the periphery, the maximum is about 140 μm in the optical axis direction in the range of 35 mm of the visual field 341 It becomes a fluctuation. Second, due to the inclination of the surface of the wafer 4 due to the warp, the position of the Fourier transform image of the wafer pattern is displaced from the spatial filter 39 installed in advance, and the spatial filtering effect is impaired. In the case of the warp of the above degree, that is, in the case of an inclination of (Δδ = 140 μm / 35 mm), as shown in FIG. 36, the positional deviation on the Fourier transform plane 361 is (140 μm / 35 mm) · (f = 70 mm) The positional deviation is 280 μm. Note that f is the focal length of the detection optical system (objective lens 37) 36.
[0081]
In order to solve these two problems, the following method is required.
As described above, a sled having a complicated shape in the entire wafer is considered to be almost flat in the field of view 341 of 35 mm. Therefore, as shown in FIG. 34 (a), an adjustment mechanism may be provided that aligns the optical axis with the normal direction at the center in the field of view 341. That is, FIG. 34B and FIGS. 35 to 38 show an apparatus for warping the wafer 4. This apparatus includes sled detection units 345a and 345b and a sled alignment mechanism unit 381.
[0082]
In other words, this apparatus (comprising the warp detecting portions 345a and 345b and the warp adjusting mechanism portion 381) includes the light source 31 (shown in FIG. 34 (b)) or the light source 349 (FIG. 35 (b)). ), An imaging optical system 346 having a mirror 348 (shown in FIG. 34B) or an imaging optical system 350 (shown in FIG. 35B), a two-divided detector (one-dimensional or two-dimensional) 347, a signal processing system 350 for processing the signals a and b from the two-divided detector 347, and a surface of a workpiece (wafer) obtained from the signal processing system 350 as shown in FIG. The controller 382 receives the signal 351 indicating the inclination Δδ and controls the drive unit, and the drive unit 383 driven by the drive signal from the controller 382. Light emitted from the light sources 31 and 349 is imaged on the two-divided detector 352 by the imaging optical systems 346 and 350. In the signal processing system 350, for example, the contrast (ab) / (a + b) is calculated by the signal a from the light receiving unit 352a and the signal b from the light receiving unit 352b in the two-divided detector 352, The entire detection optical system 36 is linearly aligned with the optical axis by the sled alignment mechanism 381 so that this value (ab) / (a + b) (shown in FIG. 37) becomes 0 (within the tilting range). It is rotated in the Δδ direction within a plane including the detector 40 and adjusted so that the normal direction of the warp and the optical axis overlap. This adjustment is automatically and independently adjusted while the detection optical system 36 and the workpiece (wafer) 4 are relatively scanned. FIG. 35A shows a state where the two-divided detector 352 detects according to the inclination of the workpiece (wafer) 4. That is, when the surface of the workpiece (wafer) 4 is not inclined, the two-divided detector 352 receives a light beam 354 indicated by a solid line located at the center line 356, and the surface of the workpiece (wafer) 4 is inclined in the Δδ direction. In this case, the two-divided detector 352 receives a light beam 355 indicated by a dotted line deviated from the center line 356.
Further, although the contrast is calculated in the signal processing system 350 described above, an operation such as a difference a−b or a ratio a / b may be performed. In addition, it is desirable that the rotation center at this time is the intersection of the optical axis and the workpiece (wafer) 4 or the vicinity thereof. This is because the visual field in the work (wafer) 4 does not vary in the direction perpendicular to the scanning direction.
[0083]
The structure of the sled fitting mechanism 381 may be a structure using a ball bearing, a structure using a leaf spring, a structure using a coil spring, a link structure, or the like, but the coil spring 388 is used in FIG. The structure is shown as an example. In this case, the rotation center of the tilt alignment is near the center of the coil spring, and is slightly away from the intersection between the optical axis and the workpiece (wafer) 4, but is considered to be sufficiently close to the intersection. This is because if the distance between the center of rotation and the intersection is d, the deviation of the field of view in the detector direction is (140 μm / 35 mm) · ( d = 35 mm) = 140 μm, which is not so large as to be a problem. Further, the center of rotation can be brought close to the above intersection using a link structure or the like. The drive system in the Δδ direction at this time may use a piezoelectric element, or may use a cam mechanism 384 attached to the output shaft of the pulse motor 383 as shown in FIG. Reference numeral 387 denotes a base (base) of the frame-shaped detection head 1a. The pulse motor 383 and the pulse motor 385 are attached to a base (base) 387. Reference numeral 389 denotes a plate member to which the illumination optical system 31 and the detection optical system 36 are attached. Therefore, the illumination optical system 31 and the detection optical system 36 are tilted in the Δδ direction around the coil spring 388 and corrected by the cam mechanism 384 by driving the pulse motor 383 to rotate. Further, when the pulse motor 385 is driven to rotate, the cam mechanism 386 corrects the displacement by Δz in the Z direction.
[0084]
Next, the automatic focus detection system will be described with reference to FIGS. That is, the warp of the workpiece (wafer) 4 becomes the inclination of the workpiece (wafer) 4 and appears as a deviation from the focal position, particularly in the peripheral portion of the workpiece (wafer) 4. Therefore, this focal position detection and adjustment mechanism is required. FIG. 39 shows an embodiment of the automatic focus detection system. The automatic focus detection system includes a light source 405, a slit 406, an imaging optical system 404, slits 401a and 401b, detectors 402a and 402b, a signal processing system 403, and drive systems 385 and 386 (shown in FIG. 38). . The light source 405 preferably has higher luminance, and an image of the slit 406 is formed on the focus position measurement object (work (wafer) 4) through the imaging optical system 404. Further, by the same imaging optical system 404, slit images formed on the workpiece (wafer) 4 are formed on slits 401a and 401b installed in front of the detectors 402a and 402b. Here, it is desirable that the slit 406 after the light source 405 and the slits 401a and 401b in front of the detectors 402a and 402b are at completely conjugate positions. That is, the slits 406, 401 a, and 401 b have the same shape and need to have different sizes by the lateral magnification of the imaging optical system 404. Here, the slits 401a and 401b installed in front of the detectors 402a and 402b are respectively rearward in the optical axis direction from the in-focus position by ΔZ.₁, Forward ΔZ₂Installed with a shift. Reference numeral 401 denotes a field stop (filter) that determines the numerical aperture (NA) of the imaging optical system 404. Reference numerals 407 and 408 denote half mirrors.
[0085]
Hereinafter, the operation of focal position detection will be described.
FIG. 41 shows a delta function (short axis direction of the slit) P (u) (shown in FIG. 41 (c)), a defocus function (Bessel function) D (u) (shown in FIG. 41 (b)) and optical. 4 shows a Fourier transform of a general transfer function (conical function) M (u) (shown in FIG. 41A), that is, a shape in a Fourier transform region. The detection signal takes a product (M (u) · D (u) · P (u)) (shown in FIG. 41 (d)) of these functions, and further has a form calculated by Fourier transform. FIG. 42 (a) shows this shape. When defocusing occurs, the image size increases and the level of the detection signal decreases. Accordingly, openings (slits) 401a and 401b having the same size are arranged, and signals (shown in FIG. 42B) passing through the openings 401a and 401b are measured by the detectors 402a and 402b. Here, if the positions of the two detectors 402a and 402b are respectively arranged at the front and rear, when defocusing occurs, one increases and one decreases as shown in FIG. Therefore, if the signal processing system 403 calculates the contrast (ab) / (a + b) of these two signals, the signal shown in FIG. 43 (b) is obtained, which passes through the 0 point (within the allowable range). Becomes the focal position. Reference numeral 405 denotes a light source, and reference numeral 406 denotes a slit forming a secondary light source.
[0086]
What should be considered in practicing the present invention are two points, how far the two detectors 402a and 402b are separated from each other, and what the numerical aperture (NA) of the imaging optical system 404 should be. This is closely related to the measurement range and measurement accuracy of the autofocus system of the present invention. Specifically, the peak depth of the output signal from one detector and the position where this output signal falls to about 1/100 from the peak position is the focal depth, and the distance between the two detectors 402a and 402b is this It is better to keep the focal length apart. Since the numerical aperture of the lens 404 determines the depth of focus, the numerical aperture is decreased when the measurement range is to be expanded, and the numerical aperture is increased when the measurement accuracy is to be improved. Since it is difficult to achieve both range and accuracy, the following techniques are available.
[0087]
A rectangular (or ellipse, oval, etc.) mask 410a as shown in FIG. 40 is placed on the pupil of the lens 404, and the numerical aperture is changed in the x and y directions. Further, the slit 406a of the secondary light source is provided with two orthogonal slits as shown in the figure, and each of them is detected separately by two sets of detectors 402a and 402b and detectors 402a 'and 402b'. At this time, since the depth of focus of each slit differs depending on the numerical aperture, the distance between the detectors 402a and 402b and the detectors 402a 'and 402b' is set to be different in each group. Specifically, in the short direction of the rectangular mask 410a, the numerical aperture is decreased, so that the depth of focus is increased and the distance between the detectors needs to be increased. FIG. 44A shows a signal a output from the detector 402a, a signal b output from the detector 402b, a signal a ′ output from the detector 402a ′, and a signal b output from the detector 402b ′. 'Indicates. FIG. 44B shows signals (a−b) / (a + b) and (a′−b ′) / (a ′ + b ′) processed by the signal processing system 403. By combining the focus detection systems of these two ranges, that is, it is possible to adjust to the high precision low range measurement range with a coarse precision high range system, so overall, high precision, high range focus detection. A system can be realized. Although slits are used here, a plurality of slits may be arranged at arbitrary positions, a ring-shaped slit having a certain width, or a combination thereof. .
[0088]
Here, a pinhole may be used instead of the slit, but by using the slit, an integration effect in the longitudinal direction of the slit appears. If a pattern such as a circuit pattern is formed on the workpiece (wafer) 4 and the image forming positions on the slits of the two detectors 402a, 402b and 402a ′, 402b ′ are slightly shifted, two detections are made. The signals of the devices 402a and 402b and 402a ′ and 402b ′ do not change in the same shape with respect to the focus change. Even if there is such a displacement of the slit due to the integration effect, the effect can be reduced.
The automatic focus detection system of this embodiment has an effect that even if the work (wafer) 4 is inclined, it can be ignored. In addition, there is an effect that the signal processing system is simpler than the type in which the fringe pattern is projected.
In the present embodiment, a slit is used as a so-called secondary light source that forms an image on the workpiece (wafer) 4. However, a point light source may be used without using a slit, or a slit ( Alternatively, a pinhole) may be used.
According to the embodiment described above, the focal position is automatically calculated without performing complicated signal processing such as fringe pattern projection.
The automatic focus detection unit may use light as shown here, may use capacitance, or may detect a change in atmospheric pressure.
[0089]
FIG. 45 and FIG. 46 show an embodiment in which both the work (wafer) warping and automatic focusing are performed. That is, the linear light beam 41 focused and illuminated on the surface of the workpiece (wafer) 4 by the illumination optical system 31 is displayed on the two-divided detector (a one-dimensional or two-dimensional image sensor) 452 by the imaging optical system 451. Then, the detection optical system 36 can be automatically focused by detecting that the linear light beam 41 is imaged at the center which is the boundary between 452a and 452b. That is, for example, the signal processing system 403 performs an operation of (ab) / (a + b) on the signal a from the light receiving unit 452a and the signal b from the light receiving unit 452b so that the value becomes zero. For example, as shown in FIG. 38, the surface of the workpiece (wafer) 4 can be automatically focused by finely moving the detection optical system 36 in the Z direction. At the same time, the linear light beam 41 focused and illuminated on the surface of the workpiece (wafer) 4 by the illumination optical system 31 is placed on the two-divided detector (which may be a one-dimensional or two-dimensional image sensor) 352 by the imaging optical system 346. The detection optical system 36 can be adjusted to the inclination of the surface of the workpiece (wafer) 4 by forming an image and detecting the formation of the linear light beam 41 at the center which is the boundary between 352a and 352b. That is, for example, the signal processing system 350 performs an operation of (a−b) / (a + b) using the signal a from the light receiving unit 352a and the signal b from the light receiving unit 352b so that the value becomes 0. As shown in FIG. 38, the surface of the workpiece (wafer) 4 can be adjusted by finely moving the detection optical system 36 in the Δδ direction. That is, FIG. 45 and FIG. 46 show examples of tilt correction and automatic focus. In the present embodiment, the detectors 352 and 452 use the two-divided element as described above, but use the light beam of the illumination optical system 31 for inspection. As shown in the figure, in the tilt detection, a two-divided detector 352 is placed so as to be divided into two in the y direction at the Fourier transform position of the inspection position (illumination point) on the wafer. In addition, the automatic focus places the two-divided detector 452 so as to be divided into two in the x direction at the imaging position of the inspection position (illumination point) on the wafer. With such a configuration, there is an effect that no new illumination is required.
[0090]
[Tenth embodiment]
Next, the inspection units (detection heads) 1a and 1a ′ are replaced with a process apparatus (a sputtering apparatus for forming a metal thin film such as Al on the wafer 4, a CVD apparatus for forming an insulating thin film on the wafer 4, an etching apparatus for performing etching, etc. (Shown in FIGS. 1, 9 and 10), a wafer transfer system 5 (shown in FIGS. 1, 9 and 10), a wafer stocker unit 131 (shown in FIG. 13), etc. Will be described with reference to FIGS. 47 and 48. FIG.
[0091]
That is, in the present invention, when the two-chip comparative inspection is performed, the rotation correction operator 187 is required as shown in FIGS. 22 to 24. This rotation correction operator can be performed by software processing (electric processing). . However, when the spatial filter (0th-order cut filter) 39 is used (shown in FIGS. 3 and 31), it is necessary to match the direction of the spatial filter 39 with the direction θ of the chip lattice formed on the wafer. Even when the spatial filter (0th-order cut filter) 39 is not used (shown in FIG. 29), it is necessary to make the orientation θ of the chip lattice formed on the wafer larger than x0 (max). On the other hand, when the wafer 4 is carried into the process apparatus and is carried by the carrying arm 5a of the handling mechanism 5, the wafer 4 is normally aligned and is in a state where a rotational deviation of ± 10 degrees or less occurs. Therefore, it is necessary to correct this rotational deviation either on the wafer side or on the inspection unit (detection head) 1a, 1a 'side.
[0092]
If the operation is to be performed on the wafer 4 side, the handling mechanism (robot mechanism) 5 needs to be slightly rotated around the tip of the transfer arm 5a (the center of the wafer 4), and the drive control of the transfer arm 5a becomes complicated. Further, a fine movement rotary stage can be provided at the tip of the transfer arm 5a and the fine movement rotary stage can be driven to rotate finely to correct the rotational deviation, but the mechanism of the transfer arm 5a becomes complicated. Further, it is conceivable to provide a rotary stage separately from the transfer arm 5a, but a space for providing this rotary stage is required. In this way, the handling mechanism (robot mechanism) 5 installed in the process processing apparatus must be special, and the commonality is lost.
[0093]
Therefore, the above-described problem can be solved by correcting the rotational deviation on the inspection unit (detection head) 1a, 1a 'side. However, the mechanisms of the inspection units (detection heads) 1a and 1a 'are somewhat complicated. FIG. 47 shows an embodiment in which rotational deviation correction is performed on the inspection units (detection heads) 1a and 1a 'side.
In the embodiment shown in FIG. 47A, for example, inspection units (detection heads) 1a and 1a ′ of three channels (three sets of the illumination optical system 31 and the detection optical system 36) are installed on the arm member 471. The entire arm member 471 is slidably supported along an arcuate guide (arced rail) 472 around the center 473 of the arm member so as to be rotatable. Reference numeral 474 denotes a gear fixed on an arc-shaped guide (arc-shaped rail) 472. A motor 475 is provided on the arm member 471, and a gear attached to the output shaft meshes with the gear 474. By rotating the motor 475, the arm member 471 rotates around 473, and a rotational deviation of ± 10 degrees or less can be corrected.
[0094]
In the embodiment shown in FIG. 47 (b), for example, inspection units (detection heads) 1a and 1a ′ of three channels (three sets of the illumination optical system 31 and the detection optical system 36) are installed on the arm member 471. The entire arm member 471 is slidably supported along an arcuate guide (arced rail) 472 around the center 473 of the arm member so as to be rotatable. Reference numeral 476 denotes a gear fixed to the arm member 471. Reference numeral 477 denotes a motor provided on an arc guide (arc rail) 472, and a gear attached to the output shaft meshes with the gear 476. By rotating the motor 477, the arm member 471 rotates about 473, and a rotational deviation of ± 10 degrees or less can be corrected.
[0095]
In the above embodiment, a circular guide whose center is the center 473 of the arm member 471 is used as the rotation guide 472. However, the guide need not be such an arc shape, and a linear guide and a link mechanism may be used.
In the embodiment shown in FIG. 47 (c), for example, inspection units (detection heads) 1a and 1a ′ of 3 channels (3 sets of illumination optical system 31 and detection optical system 36) are installed on a plate-like member 479. The plate-like member 479 is configured to be rotatably supported by an axis 473 at the tip of an arm 478 that is cantilevered to a base (base). A motor 480 is provided on the shaft center 473 at the tip of the arm 478, the output shaft of the motor 480 is directly connected to the plate member 479, and the motor 480 is driven to rotate, whereby the plate member 479 is centered on the shaft center 473. The rotational deviation of ± 10 degrees or less can be corrected.
As described above, the inspection units (detection heads) 1a and 1a ′ are cantilevered by the arm member 471 or the fixed arm 478, so that the inspection units (detection heads) 1a and 1a ′ are 473. As a mechanism for correcting a rotational deviation of ± 10 degrees or less around the center, the required space can be minimized.
[0096]
FIG. 48 shows an embodiment in which inspection units (detection heads) 1a and 1a 'having no mechanism for correcting rotational deviation are cantilevered. Reference numeral 482 denotes a plate-like member on which inspection units (detection heads) 1a and 1a 'having three channels are mounted, for example, and a mirror 35 is attached to the lower side of the plate-like member. However, the mirror 35 is not necessarily attached to the plate-like member 482 as will be described later. The plate-like member 482 is configured to be cantilever mounted on the base 481. With this configuration, the inspection units (detection heads) 1a and 1a 'can be easily removed. Since this detaching mechanism uses a steel ball or roller 483, even if it is removed, the position is reproduced at the time of re-installation, and there is an effect of eliminating the trouble of readjustment.
[0097]
Next, similarly to the embodiment shown in FIGS. 1, 9 and 10, the application of inspection units (detection heads) 1a and 1a ′ constituting the foreign matter inspection apparatus 1 to a process film forming apparatus will be described with reference to FIGS. Based on In other words, semiconductor manufacturing has been increasing in diameter for the purpose of efficient production. In addition, there is a call for shortening the number of days to complete the product (the number of days to complete the work). Single wafer processing is progressing in a processing apparatus such as a film forming apparatus and an etching apparatus as a method for solving the above-described problems. Furthermore, it is necessary to operate these devices stably and not to extend the above-mentioned completion days. The present invention solves this problem by inspecting foreign matter defects during conveyance before and after processing of a wafer. Specifically, in many process processing apparatuses, a multi-chamber system centering on the central transfer chamber 104 as shown in FIGS. 10 and 50 is used. The inspection units 1a and 1a 'described so far are installed on the central transfer chamber 104 common to this method. By doing in this way, the interface on the installation of the foreign substance inspection apparatus 1 and the process processing apparatus can be standardized, and the application of the foreign substance inspection apparatus 1 can be made smooth. Here, it is installed in the central transfer chamber 104, but it may be installed in one chamber (preliminary chamber) 501 of the multi-chamber. Further, in these processing apparatuses, a plurality of processes may be performed without releasing the wafer once put in the vacuum to the atmosphere. In such a case, it is necessary to inspect foreign matter on the wafer in vacuum. Therefore, the inspection units (detection heads) 1a and 1a ′ installed in the atmosphere are placed in the vacuum through the window (dummy port) 106d installed in the vacuum chamber shown in FIG. Is used to detect foreign matter on the wafer in the vacuum chamber. Here, the flange including the vacuum window 106d shown in FIG. 49 may be a standard product.
[0098]
FIG. 51A shows an embodiment in which the mirror 35 of the illumination optical system 31 is attached to a vacuum-compatible standard flange 106 so as to be installed in the vacuum chamber (transfer chamber) 104. FIG. 51B shows an embodiment in which the mirror 35 of the illumination optical system 31 is attached to the lower side of the window (dummy port) 106 d so as to be installed in the vacuum chamber (transfer chamber) 104. . If the illumination light is to be illuminated at an angle α of at least 60 degrees or more with respect to the surface of the wafer 4, the mirror 35 must be installed in the vacuum chamber (transfer chamber) 104. That is, if the illumination is performed through an oblique direction through a transparent window, the light collecting property cannot be secured. The objective lens 37 of the detection optical system 36 has a large NA (numerical aperture) (for example, 0.2), that is, a short focal length f (for example, f = about 40 mm) in order to improve the detection sensitivity of foreign matter. It is better to use a small lens. As a result, the gap between the lower surface of the transparent window 106 and the surface of the wafer 4 to be transferred becomes very narrow (for example, about 20 mm). Accordingly, as shown in FIG. 10B, when the mirror 35 is placed in the atmosphere, the vacuum-compatible standard flange 106 cannot be standardized and a gap is formed between the lower surface of the vacuum-compatible standard flange 106 and the surface of the wafer 4. It becomes difficult to form. On the other hand, when the mirror 35 is installed in the vacuum chamber, the vacuum-compatible standard flange 106 can be standardized, and the mirror 35 can be installed so as not to contact the surface of the wafer 4 on which the mirror 35 is conveyed with a margin. .
[0099]
In the case where the inspection units (detection heads) 1a and 1a 'are installed separately from the vacuum window 106 and can be adjusted in position, it is easy to adjust the position of the optical system with respect to the transport arm 5a. In other words, when the inspection units (detection heads) 1a and 1a ′ are removed and attached, the adjustment required at the time of installation is the entire z direction of the optical systems 31 and 36 and the linear shape of the optical systems 31 and 36. Only 2 degrees of freedom adjustment with the tilt of the field of view. Further, when using the mechanism such as the automatic tilt correction and the automatic focus following the warp of the wafer 4 described above, the optical systems 31 and 36 are installed separately from the vacuum window 106, and the position adjustable type is inevitably required. It is. (Of course, when the light intensity of the illumination optical system 31 is sufficient and the illumination light beam can be made sufficiently wide, the auto focus and the automatic tilt correction need only be performed by the detection optical system 36. There is no problem even if some parts are installed on the vacuum window 106 side.) In addition, in the case of such a type of detection system, the inspection unit (detection head) 1a, There is an effect that 1a 'can be installed. However, when the numerical aperture (NA) of the objective lens 37 of the detection optical system 36 is large (for example, 0.2 to 0.3), the aberration of the objective lens becomes a problem, and the lens system taking into account the vacuum window 106 in advance. Therefore, it is necessary to use a window as shown here for aberration correction even in the atmosphere.
FIG. 48 shows a configuration that facilitates removal of the inspection units (detection heads) 1a and 1a '. This uses a steel ball or roller 483, and even if it is removed, the position is re-established at the time of re-installation, and there is an effect of saving the trouble of readjustment.
In addition, as shown in FIG. 51B, the structure in which the illumination mirror 35 is bonded to the vacuum window 126d has an effect of simplifying the structure of the flange 106. In this case, since the gap between the detection optical system 36 and the surface of the wafer 4 can be increased, there is an effect that both the window glass 106d and the flange 106 can be thickened.
[0100]
In the case of a process in which the particle size of the film formed on the wafer 4 is large, it is desirable that the illumination be incident at a maximum incident angle (an angle close to 60 degrees). Conversely, when the film formed on the wafer has a small particle size and the film quality is almost mirror-like, it is desirable that the illumination be incident at the smallest possible incident angle (α is 80 to 85 degrees). This is because when the incident angle is large, reflection from the particle size of the film is suppressed, and foreign matter is emphasized. In addition, when the film quality is close to a mirror surface, the incident angle should be small so that forward scattering can be detected more. Therefore, in the case of the on-machine foreign matter inspection apparatus of the present invention, the film to be formed is determined for each apparatus, and therefore the incident angle that matches the film should be selected.
[0101]
Further, as shown in FIG. 52, it is desirable to install light shielding plates (filters) 521 and 522 that shield stray light ahead of an objective lens (telecentric optical system) 37 of the detection optical system 36. That is, in the above-described embodiment, since the illumination optical system 31 uses strong illumination, stray light may enter the detection image detected by the linear image sensor 40 due to reflection on the wafer surface or lens surface. is there. Therefore, light shielding plates 521 and 522 as shown in FIG. 52 are installed in the optical path of the detection optical system 36. This is the idea that the linear image sensor (detector) 40 is linear and does not effectively use all of the total luminous flux of the lens, so that the unused portion is shielded from light. In order to make this effect more effective, the light shielding plates 521 and 52 are provided.
It is preferable to install two or more stages. Furthermore, even when the inspection units (detection heads) 1a and 1a 'cannot be covered so that the indoor lighting does not enter, the inspection units (detection heads) 1a and 1a' are not affected by the indoor lighting.
[0102]
[Eleventh embodiment]
Next, the scanning mode (conveyance mode) in the foreign substance inspection will be described with reference to FIGS. FIGS. 53A and 53B show a general wafer handling mechanism (wafer transfer robot) 5. Such a structure (shoulder 5c and upper arm 5b rotated by a motor (not shown) around the shoulder 5c and a motor (not shown) around the vertical axis at the tip of the upper arm 5b). In the robot of the forearm that is rotationally driven by (1)), the transfer speed of the wafer 4 is not constant when the transfer arm 5a rotates at a constant speed. As a result, when the foreign image is detected by the linear image sensor 40, the pixel size may vary depending on the location, or the detection output may vary due to the change of the accumulation time. As described above (FIGS. 22 to 25), this becomes a problem when the corresponding points of the chip comparison are calculated.
[0103]
Therefore, 1) control the robot to move linearly, 2) control the accumulation time at the time of detection so that the detected image plane is not distorted, 3) capture the image while distorting it, and It is necessary to perform processing such as corresponding points of chip comparison at the time of rotation correction.
[0104]
Such a type of robot moves at a speed of a sine curve as shown in FIG. 54 (b) at each time. Therefore, at each time, it moves to the position of the sine curve as shown in FIG. That is, as described above, in the robot of the above type, the wafer position x has the relationship of the following equation (6) and becomes a sine curve as shown in FIG.
x = l · sin (ωt) (6)
Here, ω is each speed of the rotation axis of the robot. Therefore, the scanning speed of the wafer is represented by x dots obtained by time differentiation of x, and is represented by the following equation (7), as shown in FIG.
x (dot) = l · ω · cos (ωt) (7)
Of the corresponding methods in the case of using such a stage, the method of associating corresponding points of chip comparison at the time of wafer rotation correction by the electric circuit of 3) will be described with reference to FIG. In this method, the wafer inclination θ is first calculated based on a signal detected from the wafer rotation direction detector 110 in the rotation detection process 186 in a state where the wafer 4 is placed, and the wafer inclination θ is determined according to the wafer inclination θ. The reference table 561 determines the coordinate relationship (mpx, mpy) of the comparison target chip. In accordance with this coordinate relationship (mpx, mpy), the comparison calculation means 190 extracts information of the comparison target chip from the detection signal stored on the memory 189 and compares it. Here, the reference table 561 is used for speeding up the arithmetic processing, and is not necessarily required. The reference table 561 corresponds to the non-constant speed of wafer scanning. The wafer scanning speed (x (dot)) is uniquely determined at each position of the robot arm, and the detected image distortion when moving at a certain speed is also uniquely determined. Therefore, the wafer scanning speed is detected at each position of the robot arms 5a and 5b. Image distortion is uniquely determined. Therefore, the position coordinates of the corresponding points at the time of chip comparison can be made to correspond to each position of the robot arms 5a and 5b. This correspondence is referred to as a reference table 561.
[0105]
As an example, the length of the robot arm l = 100 mm, the initial phase of the arm ε0 = 30 degrees (arm rotation phase range−30 degrees <ε <30 degrees), the robot rotation pulse rate f0, and the pixel size ps = 7 microns. When the accumulation time ti = 1 msec and the maximum speed vm = 7 mm / sec, specific numerical values will be calculated for the case where a wafer having a chip pitch p = 10 mm is scanned with an inclination of θ = 5 degrees.
The relational coordinates of the comparison chip are indicated by the difference pixel numbers (mpx, mpy) in the x and y directions.
mpx = p · sin θ / ps = 124
mpy = p · cos θ / ps = 1423
Here, in the case of being conveyed at the maximum speed, the detection pixel becomes a square with this value. Here, when the conveyance speed is v = 0.8 · vm, when mpx = 124 pixels and mpy = 1423 pixels, the square is not formed.
In order to transport at this speed and make a square,
mpx = (p · sin θ / ps) · (vm / v) = 155
mpy = (p · cos θ / ps) = 1423
It becomes.
Here, when the rotational phase range of the arm is about −30 degrees <ε <30 degrees, there is no particular problem with the above approximate expression, but when it is wider than this, or when it is desired to manage with higher accuracy The reference table 561 is preferably created using a method that does not use the following approximation.
[0106]
x (m) = vm · (f0 / 2π) sin (2π · n / f0−ε0) + C (integral constant)
Here, when m = (2 · l / ps) · n, mpx is calculated so as to satisfy x (m + mpx) −x (m) = p · sin θ. mpy does not change.
The reference table 561 may calculate mpx and mpy corresponding to n.
Also, 2) a method for controlling the accumulation time at the time of detection so that the detected image plane is not distorted will be described.
In this method, the velocity curve (x (dot)) of the wafer (transfer arm) shown in FIG. 55 is known in advance, and the accumulation time of the linear image sensor (detector) 40 is changed corresponding to this curve. . The accumulation time is changed so that each detection pixel is a square (when the linear image sensor (detector) 40 is not a square, the figure is similar to the pixel shape of the linear image sensor (detector) 40, for example, a rectangle). is there. For this purpose, if the accumulation time is proportional to the reciprocal Ti of the stage scanning speed (x (dot)), the vertical and horizontal magnifications are constant at each position.
[0107]
That is, as shown in FIG. 56 (b), the feed position (x) of the wafer (transfer arm) is measured from the rotation angle of the robot arms 5a and 5b detected by the encoder of the transfer robot 5 by the stage pulse counter 562, The speed (x (dot)) of the wafer (transfer arm) is calculated by the calculation means 563 for each position, and the accumulation time is calculated from this speed. The timing generation unit 564 generates a timing signal 565 so that the signal from the nilia image sensor 40 is detected during the accumulation time calculated by the calculation unit 563. The image signal i detected using this signal 565 is temporarily stored in the memory 189 at the time of detection without any distortion. On the other hand, as shown in FIG. 23, the wafer inclination θ is detected by the θ detection processing 186, and the coordinates of the corresponding points are created based on this value and the chip pitch p from the design data, and the memory 189 is based on the coordinates. A signal 188 indicating a foreign object can be detected by extracting the data stored in and comparing the corresponding points with the comparison calculation means 190.
[0108]
Here, since the detection signal i has different accumulation times, the magnitude deviates from the true value. It goes without saying that the deviation of the detection signal i can be corrected by a method according to the above method. However, this correction may also enhance noise. Therefore, the method of detecting the signal after performing θ adjustment by the mechanism gives the best data.
[0109]
[Twelfth embodiment]
Next, a process apparatus having a mirror wafer will be described with reference to FIG.
FIG. 57 shows an embodiment of a process apparatus equipped with a mirror wafer. The foreign matter inspection system according to the present invention mainly inspects or monitors foreign matter on a product wafer patterned on the surface. Here, on a wafer (mirror wafer) having no pattern on the surface, foreign matter can be inspected with higher sensitivity than a product wafer. Therefore, foreign matter management of the process apparatus can be performed using a mirror surface wafer. However, in the inspection of foreign matter on the mirror-finished wafer, since it takes time and labor including the transfer of the wafer from the apparatus, it is actually impossible to inspect frequently. In addition, the trouble of cleaning and storing the mirror wafer has also been a problem.
Therefore, a mirror wafer stocker 571 is installed in the apparatus itself, and the mirror wafer 4a is transported through the apparatus at a specific frequency. The inspection unit 1a, 1a 'of the on-machine foreign matter inspection apparatus 1 according to the present invention is It was set as the structure which implements inspection. As a result, the above-described problem is solved and high-frequency device foreign matter monitoring is realized.
[0110]
The apparatus of the present invention includes a wafer stocker 571, an elevating system 572, cassette chambers 102 and 103, carry-in port 573, foreign substance inspection units 1a and 1a ', transfer arm 5a, transfer robot 5, central transfer chamber 104, process processing chamber 101, and the like. Composed. Here, the wafers 4 are stored in a cassette 132 (a type in which 25 wafers in one lot are transported, or in which a plurality of wafers having other numerical values are transported, or in which a single wafer is transported) 132. It is carried in from the carry-in entrance 573 in a state where it is placed. Here, at the position where the wafer cassette 132 is placed, a wafer stocker 572 for placing the mirror wafer 4a is placed in a state where the placed wafers 4 are parallel to each other. The position of the wafer stocker 572 on which the mirror wafer 4a is placed may not be this position but may be another place where the transfer arm 5a can easily transfer.
[0111]
Here, normally, the wafer 4 in the wafer cassette 132 is processed. Here, the mirror wafer 4a in the wafer stocker 572 is transferred at an arbitrary timing, specifically, at every wafer lot (one cassette), every several lots, or once a day. After the wafer is transported through an arbitrary transport path, specifically, a normal transport path including process processing, or a shortened path, the surface foreign matter is inspected by the foreign matter inspection units 1a and 1a '.
Further, since the mirror wafer 4a is not cleaned every time it is used and stored in the wafer stocker 572, the foreign matter on the mirror wafer 4a gradually increases with each use, as long as this change is not steep. Is not a problem. Therefore, in this monitoring, the difference between the foreign matter adhesion map (state shown in FIG. 58 (a)) before conveyance (previous inspection result) and the foreign matter adhesion map (state shown in FIG. 58 (b)) after conveyance is taken. This difference (state shown in FIG. 58 (c)) is taken as inspection data. In this way, it is possible to detect the state of foreign matter adhering to the mirror surface wafer 4a.
[0112]
Next, the foreign matter adhesion monitor at the window will be described. Here, instead of the mirror wafer 4a, the inner surface of the observation window installed in the process chamber may be directly inspected or monitored by the inspection unit 1a. In this case, since the surface is a mirror surface, inspection can be performed with high sensitivity. Moreover, there is no complication such as a transfer stock of the mirror surface wafer 4a. Further, there is an effect that it can be constantly monitored during processing, between processing, and the like. Here, the inspection unit 1a may scan and use a one-dimensional detector as described above, or may use a two-dimensional detector. Furthermore, if the relationship between the wafer surface foreign matter is grasped in advance and the state of the observation window when an abnormality occurs on the wafer surface is stored in the database in advance, it is possible to observe the wafer surface without observing it. It is possible to know the dust generation state of the device only by surface inspection of the observation window.
[0113]
Here, the processing chamber wall and the inner surface including the observation window are slowly contaminated with the process. This state is observed as a gradual change in the foreign object detection signal (the number of foreign substances or the detection signal intensity). Here, when the film is separated from the surface or abnormal foreign matter is generated, a steep change, not the above-mentioned gentle change, is observed. This steep change should be regarded as abnormal not only with a steep increase but also with a steep signal decrease. In the case of surface film peeling, it is often observed as a sharp signal decrease.
When such an abnormality is detected, cleaning of the processing chamber wall surface and other measures are taken. Furthermore, it is desirable that the observation window has a property equivalent to that of the wall surface in the apparatus in that foreign matter adheres. Specifically, it is desirable to keep the same temperature, surface roughness, material (a thin metal film or the like is vapor deposited, and the material is the same. In this case, the thin metal film transmits light). .
[0114]
Next, shading correction will be described. In the present invention, the illumination should be illuminated with more uniform intensity in order to compare the signal output between adjacent chips. However, the laser beam generally has a strong center and a weak periphery. As a result, the illumination intensity is strong near the center of the visual field on a straight line and is weak at the periphery. Therefore, a correction plate that reversely corrects this intensity distribution is inserted in the vicinity of the emission position of the illumination optical system 31 shown in FIG. 3 (before the cylindrical lens 34). The correction plate may be a curved slit, or an ND filter with reduced transmittance near the center.
[0115]
【The invention's effect】
According to the present invention, various process processing apparatuses such as a sputtering apparatus and a CVD apparatus for forming a film on a semiconductor substrate such as a semiconductor wafer and a TFT substrate, an etching apparatus for forming a pattern, a resist coating apparatus, an exposure apparatus, and a cleaning apparatus. In this case, there is an effect that it is possible to produce a semiconductor with a high yield by reducing the generation of abnormal adhered foreign matter on a semiconductor substrate such as a semiconductor wafer or a TFT substrate.
[0116]
Further, according to the present invention, various process processes such as a sputtering apparatus and a CVD apparatus for forming a film on a semiconductor substrate such as a semiconductor wafer and a TFT substrate, an etching apparatus for forming a pattern, a resist coating apparatus, an exposure apparatus, and a cleaning apparatus. In the apparatus, it is possible to perform feedback such as an alarm for the occurrence of abnormal adhering foreign matter on a semiconductor substrate such as a semiconductor wafer or a TFT substrate. By controlling process conditions such as supply gas conditions, exhaust conditions, temperature conditions, and applied voltage, it is possible to remarkably reduce the occurrence of abnormal foreign matters and to produce semiconductors at a high yield.
[0117]
Further, according to the present invention, in a product storage device for storing a large number of workpieces (semiconductor substrates) such as semiconductor wafers, TFT substrates, etc., it is possible to investigate the state of foreign matter adhering to a large number of workpieces and discharge the workpieces. It is possible to prevent a subsequent process from being continued on a workpiece on which a large number of foreign substances have adhered, and as a result, it is possible to produce a semiconductor with a high yield.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment when a foreign substance inspection apparatus is installed in a process processing apparatus according to the present invention.
FIG. 2 is a diagram showing an overall system configuration according to the present invention.
FIG. 3 is a diagram showing a specific configuration of an inspection unit (detection head) according to the present invention.
FIG. 4 is a diagram showing the relationship between the number of channels and the scanning method in an inspection unit (detection head) according to the present invention.
FIG. 5 is a diagram for explaining how to calculate an increased foreign matter map by processing according to the present invention.
FIG. 6 is a diagram showing the number of foreign matters detected in the start lot unit or wafer unit according to the present invention.
FIG. 7 is a diagram showing the maximum, minimum, and average number of foreign matters for each wafer in a construction lot unit according to the present invention.
FIG. 8 is a diagram for explaining how to estimate the cause of occurrence of abnormal foreign matter based on past analysis examples according to the present invention.
FIG. 9 is a view showing an embodiment different from FIG. 1 when a foreign substance inspection apparatus is installed in the process processing apparatus according to the present invention.
10 is a view showing an embodiment different from FIGS. 1 and 9 when a foreign substance inspection apparatus is installed in the process processing apparatus according to the present invention. FIG.
FIG. 11 is a diagram showing a system configuration in which a foreign matter inspection apparatus according to the present invention includes a wafer code identification device.
FIG. 12 is a view showing a wafer on which an identification code according to the present invention is printed.
FIG. 13 is a view showing an embodiment when a foreign substance inspection apparatus is installed in a wafer stocker according to the present invention.
14 is a diagram showing a part of the storage shelf shown in FIG. 13;
FIG. 15 is a view for explaining an embodiment for detecting the orientation flat of the wafer and detecting the rotation direction of the wafer according to the present invention.
FIG. 16 is a view for explaining an embodiment different from FIG. 15 in which the orientation flat of the wafer according to the present invention is detected to detect the rotation direction of the wafer.
FIG. 17 is a diagram for explaining an embodiment in which a chip lattice formed on a wafer according to the present invention is detected to detect a wafer rotation direction.
18 is a view for explaining an embodiment different from FIG. 17 in which the chip lattice formed on the wafer according to the present invention is detected to detect the wafer rotation direction.
FIG. 19 is a view for explaining an embodiment different from FIGS. 17 and 18 in which the chip lattice formed on the wafer according to the present invention is detected to detect the wafer rotation direction.
20 is a view for explaining an embodiment different from FIGS. 17, 18 and 19 in which a chip lattice formed on a wafer according to the present invention is detected to detect the rotation direction of the wafer. FIG.
FIG. 21 is a diagram for explaining how to detect the rotation angle of a wafer from a detection image according to the present invention.
FIG. 22 is an explanatory diagram for applying a rotation correction operator in the chip comparison according to the present invention.
FIG. 23 is a diagram showing a chip comparison system performed by software processing according to the present invention.
24 is an explanatory diagram of FIG. 23. FIG.
FIG. 25 is a diagram showing a chip comparison system using a rotation mechanism according to the present invention.
26 is an explanatory diagram of FIG. 25. FIG.
FIG. 27 is an explanatory diagram for detecting a rotation angle of a wafer from a detection image according to the present invention.
FIG. 28 is a front view showing the relationship among illumination light, diffracted light from a wafer, and numerical aperture of an objective lens.
FIG. 29 is a plan view showing the relationship among illumination light, diffracted light from a wafer, and numerical aperture of an objective lens.
FIG. 30 is a diagram showing a chip arrangement direction of a wafer.
FIG. 31 is an explanatory diagram for shielding 0th-order diffracted light with a spatial filter;
FIG. 32 is a diagram showing the relationship between the depth of focus of the detection optical system and the workpiece inspection surface in the inspection unit according to the present invention.
FIG. 33 is a diagram showing a configuration for adsorbing a wafer in a transfer arm of a handling mechanism (transfer robot) according to the present invention.
FIG. 34 is a diagram showing an embodiment of an optical system that detects the tilt of the wafer based on the warp of the wafer.
FIG. 35 is a diagram showing an embodiment different from FIG. 34 of the optical system for detecting the tilt of the wafer based on the warp of the wafer.
FIG. 36 is a diagram showing the shift of the 0th-order diffracted light at the position of the spatial filter based on the wafer warp.
FIG. 37 is a diagram showing a tilting range.
FIG. 38 is a diagram showing a mechanism for tilting and automatically focusing an inspection unit (detection head).
FIG. 39 is a diagram showing a detection optical system for automatic focusing.
FIG. 40 is a diagram showing a detection optical system for performing precise automatic focusing.
FIG. 41 is a diagram illustrating various signal processing waveforms for automatic focusing.
FIG. 42 is a diagram showing signal waveforms for automatic focusing.
FIG. 43 is a diagram showing a relationship between signals a, b, (ab) / (a + b) and ΔZ.
FIG. 44 is a diagram showing the relationship between signals a, a ′, b, b ′, (a−b) / (a + b), (a′−b ′) / (a ′ + b ′) and ΔZ.
FIG. 45 is a front view showing an optical system that performs tilt detection and focus detection using the illumination light beam of the illumination optical system.
FIG. 46 is a plan view showing an optical system that performs tilt detection and focus detection using the illumination light beam of the illumination optical system.
47 is a perspective view showing a mechanism for correcting the rotational deviation of the inspection unit (detection head) in the wafer plane. FIG.
FIG. 48 is a diagram showing a mechanism for easily mounting an inspection unit (detection head).
FIG. 49 is a diagram showing a dummy port attached to the upper cover of the transfer chamber of the process processing apparatus according to the present invention.
FIG. 50 is a diagram showing an embodiment when an inspection unit is installed in a spare room in the process processing apparatus according to the present invention.
FIG. 51 is a diagram showing an embodiment in which an inspection unit is installed outside the transfer chamber and a mirror of the illumination optical system is set in the transfer chamber in the process processing apparatus according to the present invention.
FIG. 52 is a diagram showing an example in which stray light is shielded in the inspection unit according to the present invention.
FIG. 53 is an explanatory diagram of a case where a wafer is transferred by a handling mechanism (transfer robot) according to the present invention.
FIG. 54 is a diagram showing the relationship between displacement x and speed (x (dot)) when a wafer is transferred by the handling mechanism (transfer robot) according to the present invention.
FIG. 55 is a diagram showing the relationship between the speed (x (dot)) and its reciprocal Ti when the wafer is transferred by the handling mechanism (transfer robot) according to the present invention.
FIG. 56 shows a configuration in consideration of speed fluctuation when a wafer is transferred by the handling mechanism (transfer robot) in the chip comparison according to the present invention, and a case where the wafer is transferred by the handling mechanism (transfer robot) according to the present invention. It is a figure which shows the structure which controls the accumulation | storage time in a linear image sensor in consideration of the speed fluctuation in.
FIG. 57 is a diagram showing an embodiment in which foreign matter detection is performed using a specular wafer stocked by an inspection unit in the process processing apparatus according to the present invention.
58 is a diagram for describing a technique for obtaining foreign matter detection data when a mirror wafer is used in the embodiment shown in FIG. 57. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Foreign substance inspection apparatus, 1a, 1a '... Inspection unit (detection head),
1b ... scanning stage, 3 ... Θ stage, 4 ... workpiece (wafer),
5 ... Handling mechanism (transfer robot), 5a ... Transfer arm,
6 ... buffer chamber, 7 ... process chamber,
8a, 8b ... Work supply station (loader, unloader),
9 ... Data processing unit (CPU), 10 ... Control device, 11 ... Inspection control device,
20 ... Foreign matter data analysis computer, 20g ... Database (hard disk),
21 ... Analyzer, 22 ... Inspector, 31 ... Illumination optical system, 35 ... Mirror,
36: Detection optical system, 39: Spatial filter,
37 ... Telecentric optical system (objective lens), 40 ... Linear image sensor,
41 ... Illuminated linear light beam, 91 ... Process processing device, 92 ... Processing chamber,
94: Gas flow rate measuring unit, 95: Gas pressure measuring unit,
96 ... emissivity measurement unit, equipment state data collection, 98 ... loading room,
99 ... Unloading chamber, 101 ... Reaction chamber, 102 ... Loader section,
104 ... transfer chamber, 105 ... upper lid, 106 ... standard flange for vacuum,
110 ... Wafer rotation detection system, 111 ... Wafer code identification device,
131 ... Wafer stocker, 132 ... Wafer cassette,
133 ... Wafer cassette transfer robot, 187 ... Rotation correction operator,
189... Memory, 190... Comparison processing means, 186.

Claims (10)

A semiconductor substrate supply station comprising a unloader unit having a cassette containing a loader and a semiconductor substrate having a cassette housing a semiconductor substrate,
A process chamber in which a large number of chip circuit patterns are arranged on the semiconductor substrate by performing a process on the input semiconductor substrate ;
A process processing apparatus comprising a transfer chamber having a handling mechanism for transferring a semiconductor substrate between the process processing chamber and the semiconductor substrate supply station,
Provided with a foreign matter detection device configured to detect the distribution of foreign matter attached to a semiconductor substrate transported in the transport chamber after the process processing taken out from at least the process processing chamber,
The foreign object detection device includes a chuck that sucks a semiconductor substrate transported in the transport chamber, an illumination optical system that irradiates a slit-shaped light beam that is linearly focused from an oblique direction on the surface of the semiconductor substrate , and the illumination The reflected and scattered light from the surface of the semiconductor substrate irradiated by the optical system is collected by an objective lens, and the scattered and reflected light from the edge of the circuit pattern formed on the semiconductor substrate or the spatial frequency of the repeated circuit pattern is Fourier transformed. A detection head configured to include a detection optical system that shields light with a spatial filter installed on a surface , receives the reflected scattered light that has passed through the spatial filter with a linear image sensor , converts the light into an image signal, and outputs the image signal; a scanning means for scanning and the detection head and the chuck relatively least linearly, the relative scanning direction to scan the linearly by said scanning means A rotation detection optical system for optically detecting the amount of rotation deviation in the arrangement direction of the chips on the semiconductor substrate adsorbed by the back; and the illumination optical system based on the amount of rotation deviation detected by the rotation detection optical system, A rotation deviation correction mechanism for correcting the scanning direction in which the entire detection head including the spatial filter and the linear image sensor is rotated so as to scan in the straight line to be aligned with the arrangement direction of the chips on the semiconductor substrate; In a state where the scanning direction in which the linear scanning is performed by the deviation correction mechanism is aligned with the arrangement direction of the chips on the semiconductor substrate, the scanning head is relatively positioned with respect to the semiconductor substrate attracted to the chuck. adjacent chips arranged on a semiconductor substrate by using an image signal obtained from the linear image sensor of the detection head scans at least a straight line Process treatment and wherein the the composed image signals respectively obtained from the corresponding point and a processing means for generating a distribution of foreign matter on a semiconductor substrate have groups Dzu its disagreement with chip comparison. The process processing apparatus according to claim 1, wherein the scanning unit includes a scanning stage on which the detection head is mounted or the handling mechanism . In the detection head of the foreign material detecting device, the process processing apparatus according to claim 1 or 2, characterized in that to constitute a set of the said detection optical system and the illumination optical system with a plurality disposed. In the detection head of the foreign object detection device, an inclination detection optical system for optically detecting the inclination of the surface of the semiconductor substrate attracted by the chuck, and a surface of the semiconductor substrate detected by the inclination detection optical system 4. The process according to claim 1 , further comprising an inclination correction unit that adjusts an inclination of the detection optical system itself based on an inclination to adjust the inclination of the surface of the semiconductor substrate. apparatus. In the detection head of the foreign object detection device, a defocus detection optical system for optically detecting defocus on the surface of the semiconductor substrate adsorbed by the chuck, and a semiconductor substrate detected by the defocus detection optical system 4. An automatic focusing means for automatically focusing on the surface of the semiconductor substrate by finely moving the detection optical system itself in the height direction based on the defocus of the surface of the semiconductor substrate. The process processing apparatus as described in any one. In the detection head of the foreign material detecting device, at least the illuminating optical system and the detection optical system provided outside the transfer chamber, a transparent window provided in the transfer chamber by the illumination optical system provided outside the transfer chamber the adsorbed to the chuck of the transfer chamber portion is irradiated on a semiconductor substrate, providing a diffused reflection light from the semiconductor substrate of the transfer chamber portion on the outside of the transfer chamber through a transparent window provided in the transfer chamber through process processing apparatus according to any one of claims 1 to 5, characterized by being configured to detect by the detecting optical system. Said process processing chamber, the process processing apparatus according to any one of claims 1 to 6, characterized in that it constitutes a multi-chamber around the transfer chamber. Furthermore, the distribution of foreign matter adhering to the semiconductor substrate in the process processing is managed in units of the start lot or semiconductor substrate based on the distribution of foreign matter on the semiconductor substrate after the process processing created by the processing means of the foreign matter detection device. In addition, there is a management means for generating an alarm when the distribution of foreign matter on the semiconductor substrate in the start lot or semiconductor substrate unit to be managed tends to increase due to temporal changes or becomes abnormal beyond the control value. process processing apparatus according to any one of claims 1 to 7, characterized in that the. Furthermore, the distribution of foreign matter adhering to the semiconductor substrate in the process processing is managed in units of start lots or semiconductor substrates based on the distribution of foreign matters on the semiconductor substrate after the process processing created by the processing means of the foreign matter detection device. The process created by the processing means when the distribution of foreign matters on the semiconductor substrate in the start lot or semiconductor substrate unit to be managed tends to increase due to temporal changes or becomes abnormal beyond the control value. A management means for estimating the cause of failure based on a database showing correspondence between the distribution of foreign matter on a registered semiconductor substrate and the cause of failure from the distribution of foreign matter on the semiconductor substrate after processing is provided. The process processing apparatus according to any one of claims 1 to 7 . Furthermore, the distribution of foreign matter adhering to the semiconductor substrate in the process processing is managed in units of the start lot or semiconductor substrate based on the distribution of foreign matter on the semiconductor substrate after the process processing created by the processing means of the foreign matter detection device. The process created by the processing means when the distribution of foreign matters on the semiconductor substrate in the start lot or semiconductor substrate unit to be managed tends to increase due to temporal changes or becomes abnormal beyond the control value. Management means for estimating the cause of failure from the distribution of foreign matter on the semiconductor substrate after processing based on a database indicating the correspondence between the distribution of foreign matter on the registered semiconductor substrate and the cause of the failure, and estimation by the management means And a control means for controlling the process control in the process chamber so as to remove the cause of the failure. To 7 process treatment apparatus according to any one of.

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