JP2004072088A - Substrate detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate detecting device with high precision by which a state of storing substrates in FOUP is detected accurately. <P>SOLUTION: A substrate detecting device 1 comprises an opening 11c, from which substrates W are inserted and taken out, and detects the substrates W stored in a substrate storage 11 having grooves 11d in two or more stages, the grooves 11d being provided for storing and holding the inserted plurality of substrates W substantially in a horizontal direction. The device comprises a plurality of receivers 52 which are attached to a member 59 opposed to the opening 11c and are arranged in series along the height direciton of the substrate storage 11 and a transmitter 51 which is set movably along the longitudinal direction of the substrate storage 11 and transmits a signal to the substrates W stored in the grooves 11d of the substrate storage 11. The signal transmitted from the transmitter 51 is received by the receiver 52, so that it is possible to detect the presence or absence and the state of the substrates W stored in the grooves 11d of the substrate storage 11. <P>COPYRIGHT: (C)2004,JPO

Description

【００５５】
ここで、Ｌｘは、ＰＳＤ７２の素子長（電極７２ａ、７２ｂ間の距離）である。
したがって、受信器７２は、受信した信号の強度と受信した信号の受信器７２内における受信位置とを検出可能になっている。そして、受信器７２は、受信器７２にて受信された信号の上記強度に相当する強度出力Ｉと上記受信位置に相当する位置出力Ｘｍとを出力することができる、又は、強度出力Ｉと位置出力Ｘｍとを演算可能な状態の情報（電極信号Ｉ１及びＩ２）を出力することができる。
【００５６】
以上説明したように、基板検出装置１は、複数の受信器５２が、カセット１１の開口１１ｃに対峙する部材５９に直列的に配列されて取り付けられており、発信器５１のみが上下移動して基板Ｗを検出するため、安定して発信器５１から発せられる信号を受信することができ、カセット１１内の基板の収納状態を正確に検出することができる。また、上下移動するのは発信器５１のみであり、さらに、シャッター５ａに取り付けられて移動するものであるため、基板検出装置の機構を簡略化することができる。そして、複数の受信器５２を直列的に配列することで、一体型の長尺な受信器を作製する手間も必要なく、発信器５１のみを上下移動させて基板Ｗを検出する基板検出装置を簡単に実現できる。
【００５７】
つぎに、基板検出装置１による基板Ｗを検出するための制御構成について図３をもとに説明する。図３は、発信器５１、受信器５２、基板Ｗ、シャッター５ａ及びその支持部材５ｂ、螺軸６１、ステッピングモータ６０などの関係を模式的に示している。発信器５２は、シャッター５ａ及び支持部材５ｂを介してステッピングモータ６０、螺軸６１により上下移動させられる。
【００５８】
図３において、基板検出装置１は、受信器コントローラ６３と、発信器移動コントローラ６４と、発信器コントローラ６５と、基板検出モジュール６６とを有している。受信器コントローラ６３は、受信器５２（以下、「ＰＳＤ５２」ともいう）で受信された信号の処理等を行う。発信器移動コントローラ６４は、ステッピングモータ６０を制御することで発信器５１（以下、「ＬＤ５１」ともいう）の移動位置を制御する。発信器コントローラ６５は、ＬＤ５１から照射するビームのオン、オフ切り換え及びその出力等の制御を行う。基板検出モジュール６６は、これらの各コントローラ（６３、６４、６５）と通信可能に接続され、後述するように、各溝１１ｄにおける基板Ｗの収納状態を把握する。
【００５９】
まず、基板検出モジュール６６では、シャッター駆動装置５の進退機構５ｄが、シャッター５ａを退避させてカセット１１の蓋１１ｂの取り外しが終了したタイミングで（図２参照）、エアーシリンダ５６への圧縮空気の供給切り替えを行うための電磁弁６７に対して切り替え指令を送信する。これにより、エアーシリンダ５６に対してロッド５７が前進し、ＬＤ５１がカセット１１内に進出する（図１参照）。
【００６０】
アーム５３が旋回され、ＬＤ５１がカセット１１内に進出すると、基板検出モジュール６６では、発信器移動コントローラ６４に対してパルス指令を送信するとともに、発信器コントローラ６５に対してビーム照射指令を送信する。これにより、ＬＤ５１からはビーム（信号）が照射され、発信器移動コントローラ６４では、受信したパルス指令に応じてステッピングモータ６０を回転駆動し、このモータ６０の回転に伴い、螺軸６１が回転し、シャッター５ａとともにＬＤ５１が下降を開始する。
【００６１】
ＬＤ５１の下降とともに、順次、各ＰＳＤ５２にてＬＤ５１から発せられるビームが受信されていく。このとき、カセット１１の各溝１１ｄに基板Ｗが収納されていると、基板Ｗの存在している部分では、ＬＤ５１からＰＳＤ５２へと至るビームの経路Ｓ（信号経路）が遮られる。そして、ＰＳＤ５２にて受信された信号による受信器出力（ＰＳＤ出力）は、受信器コントローラ６３により基板検出モジュー６６へと送信される。
【００６２】
受信器コントローラ６３は、各ＰＳＤ５２から電極信号Ｉ１及びＩ２を受信し、電極信号Ｉ１及びＩ２の和である強度出力Ｉと、前述した（１）式から求めることができる位置出力Ｘｍとを算出する。そして、受信器コントローラ６３は、強度出力Ｉ及び位置出力Ｘｍを基板検出モジュール６６に送信する。したがって、受信器出力（ＰＳＤ出力）としては、強度出力Ｉと位置出力Ｘｍとが受信器コントローラ６３から基板検出モジュール６６へと送信される。なお、受信器コントローラ６３が、位置出力Ｘｍの演算を行わずに強度出力Ｉのみを算出し、受信器出力として強度出力Ｉのみを基板検出モジュール６６へと送信するものであってもよい。
【００６３】
基板検出モジュール６６は、得られたＰＳＤ出力に基づいて、カセット１１の高さ方向に沿って移動中のＬＤ５１の位置と対応させて（即ち、パルス指令と対応させて）集計したＰＳＤ出力の分布を各ＰＳＤ５２ごとに（即ち、カセット１１の各溝１１ｄごとに）求める。図６は、基板Ｗが正常な状態で各溝１１ｄに収納されている場合に検出される各ＰＳＤ５２におけるＰＳＤ出力の分布を示すものである。図６では、ＰＳＤ出力の分布として強度出力Ｉの分布を示している。基板Ｗが正常な収納状態にある場合、図６に示すように、強度出力ＩとしてのＰＳＤ出力（縦軸）とＬＤ５１の位置（横軸）との関係は、１次元アレイ型の出力分布として求めることができる。そして、この得られたＰＳＤ出力の分布長さに相当する受信信号全体幅Ｃ（以下、「ＰＳＤ全体幅Ｃ」または「全体幅Ｃ」ともいう）を算出することができる。また、基板ＷによりＰＳＤ５２へと至る信号経路Ｓが遮られることでＰＳＤ全体幅Ｃにおけるビームが受信されなかった部分の長さに相当する受信信号遮断幅Ｄ（以下、「遮断幅Ｄ」または「遮光幅Ｄ」ともいう）も算出することができる。なお、溝１１ｄに基板Ｗが収納されていない場合は、遮断幅Ｄは発生しない。
【００６４】
遮断幅Ｄの値は基板Ｗの厚さによって決まるため、溝１１ｄに基板Ｗが複数枚重ねで収納されている状態では、図７に示すように、正常な状態（図６）よりも遮断幅Ｄが広がった状態として求められる。この広がった遮断幅Ｄの値により、同一の溝１１ｄに収納されている基板Ｗの枚数を把握することが可能になる。基板検出モジュール６６では、基板Ｗの寸法（基板の厚み）等に基づいて予め設定した所定の閾値Ｄｖ（以下、「既知基板幅Ｄｖ」ともいう）と、算出された遮断幅Ｄとを比較することで、各溝１１ｄに収納された基板Ｗが複数枚重ねで収納されている状態を検出することができる。
【００６５】
また、基板Ｗが斜め差し（段違い、クロススロット）で収納されている状態では、図８に示すように、正常な状態（図６）よりも全体幅Ｃが狭まった状態として求められる（図８においては、正常な状態の全体幅Ｃから狭まった部分を点線で示している）。この狭まった全体幅Ｃの値により、斜め差しの状態を把握することが可能になる。基板検出モジュール６６では、各ＰＳＤ５２における信号受信可能幅（ＰＳＤ出力分布の最大幅であり、基板Ｗが正常に収納されている状態では、ほぼＰＳＤ全体幅Ｃに一致する値）の寸法に基づいて予め設定した所定の閾値Ｃｖ（以下、「既知ＰＳＤ幅Ｃｖ」ともいう）と、得られたＰＳＤ出力の分布長さとして算出された全体幅Ｃとを比較することで、全体幅Ｃの値が、既知ＰＳＤ幅Ｃｖの値に対して変化が無ければ、基板Ｗが斜め差しで収納されていないと判断される。このように、基板検出モジュール６６は、既知ＰＳＤ幅Ｃｖと全体幅Ｃとを比較することで基板Ｗが斜め差しで収納されている状態を判断して検出することができる。
【００６６】
なお、カセット１１の蓋１１ｂをシャッター５ｂにより開く際の動作により、基板Ｗがカセット１１の各溝１１ｄから開口１１ｃ側に飛び出すようにしてずれてしまい少し傾いている状態が発生する場合がある。すなわち、図９に示すように、少し開口１１ｃ側に飛び出した状態で傾いて収納された状態になる（実線で示された正規位置から点線で示された飛び出し状態になる）ことがある。しかし、このような飛び出し状態で収納されてはいるものの、基板搬送装置８（図２参照）での取り出し操作が可能であれば正常な収納状態であると判断しても差し支えないことになる。
【００６７】
図９における正規位置に基板Ｗがある場合、図１０（ａ）に示すような波形のＰＳＤ出力分布が得られ、遮断幅Ｄの値も略同一の値になり、また、全体幅Ｃにおいて遮断幅Ｄが存在する位置（図１０において、所定の基準点Ｏから求めた、遮断幅Ｄの中心が存在する位置Ｇ）も略同一位置となる。しかし、図９における飛び出し状態に基板Ｗがある場合、図１０（ｂ）に示すような波形のＰＳＤ出力分布が得られることになる。すなわち、遮断幅Ｄの中心が存在する位置Ｇが正規位置の場合とずれ、遮断幅Ｄの幅も正規位置にある場合とは変化する。
【００６８】
このような、少し傾いて収納されてはいるもの正常な収納状態であると判断しても差し支えないような微妙な収納状態についても、正確に検出することが望ましい。そこで、基板検出モジュール６６では、前述の受信信号全体幅Ｃ及び受信信号遮断幅Ｄに加え、全体幅Ｃにおいて遮断幅Ｄの中心が存在する位置に相当する受信信号遮断位置Ｇを算出する。そして、前述した所定の閾値（既知基板幅）Ｄｖを基板Ｗの寸法および算出した遮断位置Ｇに基づいて設定し、この遮断位置Ｇに応じて設定した既知基板幅Ｄｖと遮断幅Ｄとを比較することで、図１０（ｂ）に示すようなＰＳＤ出力分布が得られた場合であっても、基板Ｗが飛び出し状態にあることを把握することができる。遮断位置Ｇに応じて既知基板幅Ｄｖを設定する具体的な例としては、例えば下式（２）に示すように遮断位置Ｇに比例して変更する方法を用いることができる。
【００６９】
【数２】

【００７０】
ただし、Ｋ１、Ｋ２は、各溝１１ｄと各ＰＳＤ５２との位置関係によって設定する定数である。
なお、既知基板幅Ｄｖを、遮断位置Ｇの一次式でなく、二次式として設定したり、遮断位置Ｇの値に応じたテーブル値として設定したり、種々の方法を選択し得る。
【００７１】
つぎに、図１１を参照しつつ、基板検出装置１による基板Ｗの収納状態を検出する処理フローについて説明する。まず、ＬＤ５１からビームを発しながＬＤ５１の下降を始め、基板Ｗのスキャンを開始する（Ｓ１０１）。ＰＳＤ５２では、ＬＤ５１から発したビームが基板Ｗの存在していない部分で受信され、この受信したＰＳＤ出力が基板検出モジュール６６へと送信される。そして、基板検出モジュール６６は、ＬＤ５２の位置情報（ステッピングモータ６０のパルス指令）とともにＰＳＤ出力の集計を行う（Ｓ１０２）。
【００７２】
基板検出モジュール６６では、前述したように、ＰＳＤ出力に基づいて、各ＰＳＤ５２ごとにおける遮断幅Ｄ（遮光幅Ｄ）および全体幅Ｃを算出する（Ｓ１０３）。このとき、ＰＳＤ出力については、所定の閾値を境に判定して求めた２値化信号として処理してもよい。そして、ＰＳＤ出力ごとに、全体幅Ｃ中に遮光が存在するか否か（すなわち、遮光幅Ｄがゼロでない値として算出できるか否か）を判断する（Ｓ１０４）。判断対象となっている当該ＰＳＤ出力に、遮光が無ければ、さらに、当該全体幅Ｃと前述の既知ＰＳＤ幅Ｃｖとを比較する（Ｓ１０５）。当該全体幅Ｃの値が、既知ＰＳＤ幅Ｃｖの値に対して変化が無ければ、当該ＰＳＤ出力に対応する溝１１ｄには基板Ｗが存在していないと判断される（Ｓ１０６）。変化がある場合は、図８を用いて説明したように、斜め差し（クロススロット）の状態にあると判断される（Ｓ１１１）。
【００７３】
また、処理ステップＳ１０４にて、当該全体幅Ｃ中に遮光が存在すると判断された場合（遮光幅Ｄが算出された場合）は、当該遮光幅Ｄを前述の既知基板幅Ｄｖと比較する（Ｓ１０７）。この比較においては、当該遮光幅Ｄの値と既知基板幅Ｄｖの値と大小を比較し（Ｓ１０８）、当該遮光幅Ｄが既知基板幅Ｄｖより小さければ、当該ＰＳＤ出力に対応する溝１１ｄには、基板Ｗが１枚収納されている（即ち、正常な状態で収納されている）と判断する（Ｓ１０９）。なお、既知基板幅Ｄｖの値としては、基板１枚の厚みよりも大きく２枚の厚みよりも小さい寸法を判定できる値にしておく。また、前述のように、既知基板幅Ｄｖとしては、遮断位置Ｇに基づいた設定にすることで、図９を用いて説明した飛び出し状態ではあるが正常な収納状態を検出することができる。
【００７４】
ステップＳ１０８にて、当該遮光幅Ｄが、既知基板幅Ｄｖよりも大きければ、さらに、当該ＰＳＤ出力に対応する溝１１ｄに基板Ｗが複数枚収納されているのか、あるいはクロススロットの状態にあるのかの判断が行われる（Ｓ１１０）。ステップＳ１０５においては、クロススロットの状態を全体幅Ｃの変化を判断することで検出するが、基板Ｗの位置と、隣り合うＰＳＤ間のＰＳＤが配列されていない部分（不感帯）の長さ、ＰＳＤ５２と溝１１ｄとの位置関係、などによっては、クロススロット状態であっても遮光が生じる場合（遮光幅Ｄが発生している場合）がある。この場合、通常想定される基板Ｗが複数枚重ねになった状態よりも、遮光幅Ｄがさらに大きくなる。したがって、この閾値を既知複数枚基板幅として設定しておき、この既知複数枚基板幅と遮光幅Ｄとを比較することで（Ｗ１０８）、複数枚重ね状態であるかクロススロット状態であるか判定できる。すなわち、遮光幅Ｄが既知複数枚基板幅よりも大きければ、クロススロット状態と判断し（Ｓ１１１）、当該ＰＳＤ出力に対応する溝１１ｄは、基板設置異常であると判断される（Ｓ１１２）。また、遮光幅Ｄが既知複数枚基板幅より大きくなければ、複数枚重ね状態であると判断し（Ｓ１１３）、当該ＰＳＤ出力に対応する溝１１ｄが、基板設置異常であると判断される（Ｓ１１４）。
【００７５】
以上説明した処理を基板検出モジュール６６にて行うことにより、カセット１１内における全ての溝１１ｄに対しての基板Ｗの収納状態を正確に検出することができ、複数枚重ねや斜め差しといった不規則な基板収納状態についても、正確に把握することが可能になる。
【００７６】
最後に、本実施形態例に係る基板検出装置１の動作について、既述した部分については適宜割愛しながら説明する。まず、図２において、図示しない搬送設備等によって搬送されてきたカセット１１が、載置部３のカセットステージ２の上に載置される。載置された後、カセット１１は、カセット駆動機構４によって前進駆動される。このとき、シャッター５ａは、通過口１０ａを塞いでいる。そして、カセット１１がシャッター５ａに近接する位置にまで移動してくると、シャッター５ａに設けられている図示しないロック機構が、カセット１の蓋１１ｂに設けられた固定機構１１ｅのピニオン１１ｇと連結し、固定機構１１ｅが解除され（図１９参照）、容器１１ａから蓋１１ｂを取り外し可能な状態となるとともに、蓋１１ｂがシャッター５ａに保持される。
【００７７】
つぎに、シャッター５ａは、シャッター進退機構５ｄにより後退させられる。後退することで、カセット１の開口１１ｃは、開いた状態となり、蓋１１ｂを保持したシャッター５ａとカセット１１との間に空間が生じる。
ここで図１を参照すると、後退した後の状態のシャッター５ａが図示されており、そして、エアーシリンダ５６およびロッド５７により旋回揺動される前の状態のアーム５３が実線で図示されている。この状態から、ロッド５７のエアーシリンダ５６に対する前進動作により、リンク部材（５５ａ、５５ｂ）および揺動軸５４を介して、アーム５３が２点鎖線の位置まで揺動し、アーム５３の一端５３ａに取り付けられたＬＤ５１が、カセット１１内に進出する。
【００７８】
ＬＤ５１が、カセット１１内に進出すると、ＬＤ５１からは、受信器５２に向かって線光が発せられる。そして、シャッター駆動装置５の昇降機構５ｃによって、シャッター５ａが降下するとともに、ＬＤ５１とＰＳＤ５２との間で走査されるようにして、基板Ｗが存在しているところでは、信号経路が遮られ、基板Ｗが存在していないところでは、信号経路が遮られずに、ＰＳＤ５２まで信号が到達して受信される。
【００７９】
そして、ＬＤ５１の降下とともに、順次、移動中のＬＤ５１の位置に対応する各ＰＳＤ５２の出力が得られる。シャッター５ａの降下とともに、ＬＤ５１が、カセット１１の最下段の溝１１ｄの通過が完了すると、全てのＰＳＤ５２についての出力が得られるとともに、基板検出モージュール６６にて、前述したように各溝１１ｄにおける基板Ｗの収納状態が検出され、当該カセット１１の基板収納情報が得られる。そして、例えば、基板処理装置１の処理部９にて、当該カセット１１の処理が行われる場合に、この基板収納情報に基づいて、カセット１１の特定に溝１１ｄから基板Ｗを取り出すとともに、処理後さらにその基板Ｗを取り出した特定の溝１１ｄへと返却収納するような場合に利用されることになる。
【００８０】
なお、カセット１１内で、基板Ｗの検出のための信号発信が終了すると、アーム５３は、通過口１０ａに突出した状態から、再び、図１に実線で示す状態へと退避する。
【００８１】
以上が、本実施形態例に係る基板検出装置１についての説明であるが、この基板検出装置１によると、簡易な装置構成で、ＦＯＵＰ内の基板の収納状態を正確に検出可能な高精度の検出装置を得ることができる。
【００８２】
また、実施の形態は、上記に限定されるものではなく、例えば、次のように変更して実施してもよい。
【００８３】
（１）本実施形態においては、カセット１１の高さ方向に沿って移動中のＬＤ７１（発信器７１）の位置と対応させて集計するＰＳＤ出力（受信器出力）として強度出力Ｉのみを用いる例を説明したが、強度出力Ｉ及び位置出力Ｘｍ両方ともに用いて集計するものであってもよい。
【００８４】
図１２は、基板Ｗが傾いている場合の信号経路を説明する図である。発信器５１の光軸（線光の照射方向）に対して基板Ｗが僅かに傾くと、ＬＤ５１から照射された信号は、基板Ｗの側面と反射して遮られるだけでなく、基板の表面とも反射して遮られることになる。即ち、基板Ｗの表面で反射すると、ＬＤ５１からＰＳＤ５２へと至る信号経路は折れ曲がり、ＰＳＤ５２に斜めに信号が入射することになる。このとき、基板Ｗの表面の反射率が高いと、図１２（ａ）に示すように、基板Ｗの表面で反射し、信号は、ほとんど減衰することなくＰＳＤ５２に入射する。一方、基板Ｗの表面の反射率が低いと、図１２（ｂ）に示すように、基板Ｗの表面で反射し、信号は、大きく減衰してＰＳＤ５２に入射する。このように、基板Ｗの表面の反射率が異なると、図１２（ａ）及び（ｂ）に示すように、基板Ｗの傾き角度が同じでも、信号が受信されなかった部分の長さとして算出される遮断幅Ｄの大きさが大きく異なってしまう場合がある。このため、カセット１１内に収納されている基板Ｗとして、反射率が高いものと低いものとが混在している場合、基板Ｗの収納状態を判断するために遮断幅Ｄと比較する所定の閾値（既知基板幅Ｄｖなど）を適切に設定できない場合がある。
【００８５】
そこで、基板検出モジュール６６が、ＰＳＤ５２（受信器５２）にて受信された信号による強度出力Ｉと位置出力Ｘｍ（受信器コントローラ６３で算出された出力Ｉ、Ｘｍ）とに基づいて、カセット１１の各溝１１ｄごとに、カセット１１の高さ方向に沿って移動中のＬＤ５１（発信器５１）の位置と対応させて集計した強度出力Ｉの分布長さに相当する受信信号全体幅Ｃ１を算出する。そして、同様に、各溝１１ｄごとに、基板ＷによりＰＳＤ５２へと至る信号経路が遮られることで全体幅Ｃ１におけるＬＤ５１からの１本の直線経路のみを経て受信される信号（基板Ｗの表面で反射されずにＬＤ５１から直接ＰＳＤ５２へと入射する信号）が受信されなかった部分の長さに相当する受信信号遮断幅Ｄ２を算出する。
【００８６】
図１３は、上記の全体幅Ｃ１及び遮断幅Ｄ２の算出方法を説明する図であって、基板Ｗが傾いて収納されている場合に検出されるＰＳＤ５２の強度出力Ｉ及び位置出力ＸｍをＬＤ５１の位置に対応させて集計した分布を示す図である。また、図１４は、図１３の検出例に対応する基板Ｗの収納状態を説明する図である。なお、図１４では、基板ＷのＰＳＤ５２側が少し持ち上がるように傾いている状態を例示している。
【００８７】
ＬＤ５１の位置に対するＰＳＤ５２の位置出力Ｘｍは、信号が基板Ｗに遮られずに直進して入射するときは直線的に変化し、図１３に示す線形領域の分布となる。一方、信号が基板Ｗに遮られるときは、電極信号Ｉ１、Ｉ２が適切に得られず、式（１）をもとに位置出力Ｘｍを算出することができない。したがって、強度出力Ｉが予め設定した所定の閾値Ｉｖ（強度閾値Ｉｖ）より小さいときには、基板検出モジュール６６は、位置出力Ｘｍを無視し、データ無しとして処理する。
【００８８】
また、信号が、基板Ｗの表面で反射して遮られると、基板Ｗの表面で信号経路が折れ曲がるため、図１４の例では、ＰＳＤ７２への信号入射位置が、ＬＤ５１の移動方向と逆方向に移動することになる。このため、位置出力Ｘｍの分布は、図１３に示すように、直線状の線形領域の分布から外れて曲線状の反射領域の分布となる。
【００８９】
ここで、本実施形態と同様に、基板検出モジュール６６が、強度出力Ｉが強度閾値Ｉｖ以下となる部分の長さ（信号が受信されなかった部分の長さに相当する）を算出すると、遮断幅の長さはＤ１と算出されることになる。しかし、反射領域の存在も考慮し、基板検出モジュール６６は、強度出力Ｉが強度閾値Ｉｖ以下の部分と、強度出力Ｉが強度閾値Ｉｖ以上であっても位置出力Ｘｍが線形領域以外となる部分とを合わせた長さＤ２を算出する。
【００９０】
なお、位置出力Ｘｍが、線形領域以外であるかどうかの判定は、下式（３）による判定方法Ｍ１や、下式（４）による判定方法Ｍ２などに基づいて行うことができる。
【００９１】
【数３】

【００９２】
【数４】

【００９３】
判定方法Ｍ１は、上式（３）によって算出したΔ１の絶対値が予め設定した所定の閾値を超える場合に線形領域以外であると判断する方法である。なお、式（３）中におけるＬＤ位置とは図１３示すＬＤ位置の座標であり、Ａ１、Ａ２は定数である。
【００９４】
また、判定方法Ｍ２は、予め機器調整時などに基板Ｗが無い状態で測定しておいた位置出力Ｘｍの参照値と位置出力Ｘｍとの差Δ２を（４）式に基づいて算出し、Δ２が予め設定しておいた所定の閾値を超える場合に線形領域以外であると判断する方法である。
【００９５】
以上のように、全体幅Ｃ１及び遮断幅Ｄ２を算出すると、次いで、基板検出モジュール６６は、本実施形態の場合と同様の手順により基板Ｗの収納状態を判断する。即ち、基板検出モジュール６６は、まず、各ＰＳＤ５２における信号受信可能幅の寸法に基づいて予め設定した所定の閾値Ｃｖ（既知ＰＳＤ幅Ｃｖ）と全体幅Ｃ１とを比較するとともに、基板Ｗの寸法に基づいて予め設定した所定の閾値Ｄｖ（既知基板幅Ｄｖ）と遮断幅Ｄ２とを比較する。これにより、各溝１１ｄに収納された基板Ｗの収納状態を判断する。
【００９６】
以上、図１３及び１４を参照しながら説明した変形例によると、基板Ｗの表面で反射して受信された信号を除去して、全体幅Ｃ１及び遮断幅Ｄ２を演算することができる。これにより、基板表面の反射率が大きく異なる基板Ｗが混在する場合でも、反射率の違いによる影響によらず基板Ｗの傾き状態を正確に評価することが可能になる。したがって、本実施形態の場合と同様の作用効果を奏するとともに、基板表面の反射率が異なる基板Ｗがカセット１１内に混在していても正確に基板Ｗの収納状態を検出することができる。
【００９７】
（２）また、基板検出モジュール７６が、強度出力Ｉ及び位置出力Ｘｍ両方ともに用いて集計するものである場合、上記の変形例とは異なる集計方法を選択しているものであってもよい。図１５は、図１４に示す状態の基板Ｗを検出する場合において、上記変形例とは異なる方法で強度出力Ｉ及び位置出力Ｘｍを集計して基板収納状態を判断する例を説明する図である。
【００９８】
まず、ＬＤ５１がカセット１１の高さ方向に沿って移動したときにＰＳＤ５２にて受信された信号をもとに、受信器コントローラ６３が、強度出力Ｉと位置出力Ｘｍとを算出してこれを基板検出モジュール６６に送信する。そして、図１５（ａ）に示すように、基板検出モジュール６６が、ＰＳＤ５２にて受信された信号による強度出力Ｉと位置出力Ｘｍとに基づいて、カセット１１の各溝１１ｄごとに、位置出力Ｘｍに対応させて集計した強度出力Ｉの分布を求める。図１４の例のように基板Ｗの表面で反射した後にＰＳＤ５２で受信される信号は、ＰＳＤ５２への信号入射位置がＬＤ５１の移動方向と逆方向に移動するとともに、強度出力Ｉが減少していくことになる。このため、図１５（ａ）に示すように、位置出力Ｘｍに対応させて集計した強度出力Ｉの分布は、多価関数的な反射領域の分布となる。なお、図１５（ａ）では、強度出力Ｉが、強度閾値Ｉｖ以下のときは、データ無しとして処理している場合を示している。
【００９９】
次に、基板検出モジュール６６は、同一の位置出力Ｘｍに対して複数の強度出力Ｉが存在している場（図１５（ａ）の場合）には、図１５（ｂ）に示すように強度出力Ｉの値の大きい方のみを残した一価関数的な分布に修正する。
【０１００】
そして、基板検出モジュール６６は、図１５（ａ）又は図１５（ｂ）の分布から、強度出力Ｉの分布長さに相当する受信信号全体幅Ｃ２を算出する。また、図１５（ｂ）の分布から、強度出力Ｉの分布が存在しない部分の長さＤ３を算出する。この長さＤ３を算出することで、基板ＷによりＰＳＤ５２へと至る信号経路が遮られることで全体幅Ｃ２におけるＬＤ５１からの１本の直線経路のみを経て受信される信号が受信されなかった部分の長さに相当する受信信号遮断幅Ｄ３を算出したことになる。
【０１０１】
以上のように、全体幅Ｃ２及び遮断幅Ｄ３を算出すると、次いで、基板検出モジュール６６は、本実施形態の場合と同様の手順により基板Ｗの収納状態を判断する。即ち、基板検出モジュール６６は、まず、各ＰＳＤ５２における信号受信可能幅の寸法に基づいて予め設定した所定の閾値Ｃｖ（既知ＰＳＤ幅Ｃｖ）と全体幅Ｃ２とを比較するとともに、基板Ｗの寸法に基づいて予め設定した所定の閾値Ｄｖ（既知基板幅Ｄｖ）と遮断幅Ｄ３とを比較する。これにより、各溝１１ｄに収納された基板Ｗの収納状態を判断する。
【０１０２】
以上、図１５を参照しながら説明した変形例によると、基板Ｗの表面で反射して受信された信号を除去して、全体幅Ｃ２及び遮断幅Ｄ３を演算することができる。これにより、基板表面の反射率が大きく異なる基板Ｗが存在する場合でも、反射率の違いによる影響によらず基板Ｗの傾き状態を正確に評価することができる。したがって、本実施形態の場合と同様の作用効果を奏するとともに、基板表面の反射率が異なる基板Ｗがカセット１１内に混在していても正確に基板Ｗの収納状態を検出することができる。
【０１０３】
また、ＬＤ５１（発信器５１）が移動する際の位置情報が無くても、カセット１１の高さ方向に沿った全体幅Ｃ２と遮断幅Ｄ３とを算出することができる。即ち、全体幅Ｃ２及び遮断幅Ｄ３の算出にＬＤ５１の位置に関する情報を必要としないため、発信器５１の移動機構としては、ステッピングモータ６０などの移動中の位置を高精度に検出できるものを用いる必要がない。例えば、発信器５１の昇降機構５ｃとしてエアシリンダなどの簡易な機構を用いて、発信器５１の移動機構を簡略化できる。
【０１０４】
（３）本実施形態においては、各受信器５２がカセット１１の各溝１１ｄにそれぞれ対応するように設けられていたが、必ずしもこの通りでなくてもよい。例えば、図１６に示すように、各受信器５２がカセット１１における各溝１１ｄの複数段毎（図１６では、２段毎）に対応するように設けられるものであっても、本発明の効果を奏し得る。この場合には、遮断幅Ｄによって、複数枚重ね状態およびクロススロット状態の判定を行う。なお、この場合、ＰＳＤ出力分布中において、複数の遮断幅Ｄが存在することもあるが、本実施形態と同様にしてＰＳＤ全体幅を算出し、合わせてこのＰＳＤ全体幅の中心位置を算出して、ＰＳＤ全体幅及びその中心位置の変化の様子を把握することで、クロススロット状態を判断し検出することができる。
【０１０５】
（４）図１６の変形例に示すように、隣り合う受信器５２間には受信器５２が配列されていない部分（不感帯）が存在するが、カセット１１の高さ方向に沿って直列的に配列される複数の受信器５２が、少なくとも不感帯の長さに相当する距離分は、カセット１１の高さ方向に移動可能に設けられているものであってもよい。すなわち、例えば、図２に示す部材５９が、上下に不感帯長さに相当する距離分だけ往復動作を行うものなどであってもよい。このような構成にすることで、発信器５１を一旦上下移動させて基板Ｗの収納状態を検出した後、受信器５２を、不感帯の長さに相当する距離分上下に移動させ、再度発信器５１を上下移動させて基板Ｗの収納状態を検出させることができる。そして、受信器５２にて２度にわたってそれぞれ受信された信号によるこれらの受信器出力を重ね合わせることで、受信器５２が配設されていない部分が存在していない場合と同様の受信器出力を得ることができる。したがって、各溝１１ｄにおける基板Ｗの収納状態を正確に検出することができるとともに、複数の受信器５２を無駄なく効率よく配列することができる。
【０１０６】
（５）また、本実施形態においては、カセット１１の高さ方向に沿って直列的に配列される複数の受信器は、単列に配列されていたが、必ずしもこの通りでなくてもよい。すなわち、複数の受信器５２が、カセット１１の高さ方向に沿う複数列に配列されているものであってもよい。図１７は、この変形例を示したものであり、２列に配列された受信器列（受信器列６８ａおよび受信器列６８ｂ）と発信器５１との位置関係を上から見た様子を表した模式図である。発信器５１から発せられた線光の一部は、ハーフミラー６９を介して分光され、受信器列６８ａに配列された受信器５２にて受信される。また、ハーフミラー６９を通過した残りの線光は、プリズム７０で屈折され、受信器列６８ｂに配列された受信器５２にて受信される。そして、複数の受信器列６８ａ及び６８ｂは、カセット１１の高さ方向における各受信器５２の位置を互いにずらすようにして各受信器５２が配設されている。このため、一方の受信器列においては受信器５２が配設されていない部分（不感帯）が存在していても、その部分に対応する位置に、他方の受信器列においては受信器５２が配設されている状態にすることができる。これにより、発信器５１にて一旦基板Ｗの収納状態を検出した後、単列に配設された受信器列を不感帯に相当する距離だけ上下に移動させ、再度発信器５１を上下移動させて基板Ｗの収納状態を検出する場合と同様の効果が得られる。すなわち、それぞれの受信器列（６８ａ及び６８ｂ）で受信された受信器出力を重ね合わせることで、不感帯が存在しない場合と同様の受信器出力を得ることができるという効果が得られる。したがって、カセット１１の各溝１１ｄにおける基板Ｗの収納状態を正確に検出することができるとともに、複数の受信器５２を無駄なく効率よく配列することができる。
【０１０７】
また、図１７に示す変形例においては、発信器５１から信号として発せられる線光の受信器５２へと至る経路を、ハーフミラー６９を用いて分光することで、複数の受信器列（６８ａ、６８ｂ）に配列される各受信器５２に向かってそれぞれ線光を発することができる。これにより、直列的に配列される複数の受信器５２を複数列に配列している場合であっても、１つの発信器５１によって、複数列に配列されるそれぞれの受信器列（６８ａ、６８ｂ）に向かって同時に線光を発することができる。したがって、基板検出装置１の装置構成を簡略化できる。なお、複数の受信器列は、３列以上に設けられているものであってもよい。この場合、ハーフミラーで２度以上分光することで、各受信器列の受信器に対して線光を発することができる。
【０１０８】
（６）本実施形態においては、発信器５１から発せられた線光をそのまま受信器５２にて受信する例を説明しているが、必ずしもこのとおりでなくてもよく、発信器５１から信号として発せられる線光（ビーム）の照射径を集光手段により縮径することで、受信器５２に向かってこの縮径されたビームが発せられるものであってもよい。集光手段として、例えば、発信器５１と受信器５２との間にレンズを配し、これにより発信器５１から発したビームの照射径を絞ることができる。この構成によると、照射されたビームが拡散してしまうことを防止でき、発信器５１から受信器５２へと至る安定したビームの経路を容易に形成することができる。このため、受信器５２における発信器５１から発せられたビームの受信精度が向上し、ＦＯＵＰ内における基板Ｗの収納状態を正確に検出できる。
【０１０９】
（７）また、発信器５１から信号として発せられる線光の受信器５２へと至る経路を、線光反射手段または線光屈折手段あるいは線光誘導手段を用いて変更することで、受信器５２への線光照射角度を調整するものであってもよい。線光反射手段としては、図１７に示すようにミラー等を用いることができ、また、線光屈折手段としては、図１７に示すようにプリズム等を用いることができる。線光誘導手段としては、光ファイバのような光導管を用い、例えば、図１における発信器５１の取り付け位置まで光ファイバの先端を延ばして取り付け、その先端から線光を発するものであってもよい。このように、線光反射手段又は線光屈折手段あるいは線光誘導手段を用いることで、受信器５２への線光照射角度を容易に調整することができ、線光の受信精度を向上させることができる。
【０１１０】
（８）図１８（ａ）の模式図に示すように、本実施形態においては、発信器５１を揺動動作可能なアーム５３に取り付け、発信器５１をカセット１１内に進出可能にするものであるが必ずしもこの通りでなくてもよい。例えば、図１８（ｂ）に示すように、複数のリンク部材が蛇腹状に組み合わされ、カセット１１に対して垂直に進退可能な（図中両端矢印方向に往復動作可能な）蛇腹アーム７１の先端に発信器５１が取り付けられているようなものであってもよい。この構成によっても、本発明と同様の効果を奏し得る。
【０１１１】
（９）本実施形態においては、発信器５１のみがカセット１１内に向かって進退可能に取り付けられていたが、複数の受信器５２も、カセット１１内に向かって進退可能にもうけられるものであってもよい。例えば、図２に示す部材５９に対して、複数の受信器５２を一体的に支持するアームを取り付け、このアームがカセット１１内に向かって進退可能に支持されているものであってもよい。
【０１１２】
（１０）本実施形態においては、発信器５１は、シャッター５ａに対して取り付けられているものであるが、シャッター駆動装置５とは別途設けられる昇降装置に取り付けられているものであっても本発明と同様の効果が得られる。
【０１１３】
（１１）本実施形態においては、複数の受信器５２は、隔壁１０に平行に延設された部材５９に対して取り付けられているが、隔壁１０に一体に複数の受信器５２が取り付けられているものであっても本発明と同様の効果が得られる。
【０１１４】
（１２）本実施形態においては、発信器５１と受信器５２との間に形成される信号経路が、基板Ｗの存在によって遮られることにより、基板Ｗの収納状態を検出していくものであるが、必ずしもこの通りでなくてもよい。例えば、基板Ｗの周囲側面に反射した信号を受信器５２で受信することで、基板Ｗの存在を検出するものであってもよい。
【０１１５】
【発明の効果】
以上説明したように、請求項１の発明によると、複数の受信器が、基板収納容器の開口に対峙する部材に直列的に配列されて取り付けられており、発信器のみが上下移動して基板を検出するため、安定して発信器から発せられる信号を受信することができ、ＦＯＵＰ内の基板の収納状態を正確に検出することができる。また、上下移動するのは発信器のみであるので、基板検出装置の機構を簡略化することができる。そして、複数の受信器を直列的に配列することで、一体型の長尺な受信器を作製する手間も必要なく、発信器のみを上下移動させて基板を検出する基板検出装置を簡単に実現できる。したがって、簡易な装置構成で、ＦＯＵＰ内の基板の収納状態を正確に検出可能な高精度の検出装置を得ることができる。
【０１１６】
請求項２の発明によると、基板収納容器内に向かって進出した発信器と、直列的に配列された受信器との間に形成される信号経路が、基板に遮られることにより、基板検出が行われるものであるため、確実で正確な基板検出が可能になる。また、発信器は、遮蔽板駆動装置に取り付けられており、遮蔽板駆動装置の昇降動作とともに、基板の検出が行われるため、迅速な検出が可能になるとともに、発信器用の上下移動機構を別途設ける必要がなく、基板検出装置の機構が簡略化できる。
【０１１７】
請求項３の発明によると、各溝における基板の収納状態を正確に検出することができるとともに、複数の受信器を無駄なく効率よく配列することができる。
【０１１８】
請求項４の発明によると、発信器から受信器へと至る安定した線光経路を形成することが容易になり、発信器から発せられた線光の受信精度が向上し、ＦＯＵＰ内における基板の収納状態を正確に検出できる。
【０１１９】
請求項５の発明によると、受信器への線光照射角度を容易に調整することができ、線光の受信精度を向上させることができる。
【０１２０】
請求項６の発明によると、受信信号遮断幅を算出して所定の閾値と比較することで、基板が複数枚重ねで収納されている状態を検出することができ、また、受信信号全体幅を算出して所定の閾値と比較することで、基板が斜め差しで収納されている状態を検出することができる。したがって、不規則な基板収納状態についても、正確に検出することが可能になる。
【０１２１】
請求項７の発明によると、基板の表面で反射して受信された信号を除去して、受信信号全体幅及び受信信号遮断幅を演算することができる。これにより、基板表面の反射率が大きく異なる基板が混在する場合でも、反射率の違いによる影響によらず基板の傾き状態を正確に評価することが可能になる。そして、受信信号遮断幅と所定の閾値とを比較することで基板が複数枚重ねで収納されている状態を検出でき、受信信号全体幅を所定の閾値と比較することで基板が斜め差しで収納されている状態を検出できる。したがって、基板表面の反射率が異なる基板が基板収納容器内に混在していても正確に基板の収納状態を検出することができる。
【０１２２】
請求項８の発明によると、基板の表面で反射して受信された信号を除去して、受信信号全体幅及び受信信号遮断幅を演算することができる。これにより、基板表面の反射率が大きく異なる基板が存在する場合でも、反射率の違いによる影響によらず基板の傾き状態を正確に評価することができる。そして、受信信号遮断幅と所定の閾値とを比較することで基板が複数枚重ねで収納されている状態を検出でき、受信信号全体幅を所定の閾値と比較することで基板が斜め差しで収納されている状態を検出できる。したがって、基板表面の反射率が異なる基板が基板収納容器内に混在していても正確に基板の収納状態を検出することができる。
【０１２３】
請求項９の発明によると、受信信号遮断幅を算出して所定の閾値と比較することで、基板が複数枚重ねで収納されている状態を検出することができ、また、受信信号全体幅を算出して所定の閾値と比較することで、基板が斜め差しで収納されている状態を検出することができる。すなわち、不規則な基板収納状態についても、正確に検出することが可能になる。そして、受信信号遮断幅を、受信信号遮断位置に基づいて設定する所定の閾値と比較することで、ＦＯＵＰの各溝から開口側にずれてしまい少し傾いて収納されてはいるものの正常な収納状態であると判断しても差し支えないような微妙な収納状態についても正確に検出することができる。
【０１２４】
請求項１０の発明によると、発信器を一旦上下移動させて基板の収納状態を検出した後、受信器を、隣り合う受信器間の受信器が配設されていない部分の長さに相当する距離分上下に移動させ、再度発信器を上下移動させて基板の収納状態を検出させることができる。そして、受信器にて受信された信号によるこれらの受信器出力を重ね合わせることで、受信器が配設されていない部分が存在していない場合と同様の受信器出力を得ることができる。したがって、各溝における基板の収納状態を正確に検出することができるとともに、複数の受信器を無駄なく効率よく配列することができる。
【０１２５】
請求項１１の発明によると、複数列に配列されたそれぞれの受信器列を、基板収納容器高さ方向における各受信器の位置を互いにずらすようにして各受信器を配設することができる。これにより、一つの受信器列においては受信器が配設されていない部分が存在していても、その部分に対応する位置に、他の受信器列においては受信器が配設されている状態にすることができる。したがって、各溝における基板の収納状態を正確に検出することができるとともに、複数の受信器を無駄なく効率よく配列することができる。また、基板の飛び出しによる傾きを検出することもできる。
【０１２６】
請求項１２の発明によると、直列的に配列される複数の受信器を複数列に配列している場合であっても、一つの発信器によって、複数列に配列されるそれぞれの受信器列に向かって同時に線光を発することができる。したがって、装置構成を簡略化できる。
【図面の簡単な説明】
【図１】本発明の一実施形態に係る基板検出装置が、基板処理装置に取り付けられている状態を例示する図であり、図１（ａ）は上面図、図１（ｂ）は基板処理装置側から見た図を示す。
【図２】図１に示す基板検出装置が取り付けられる基板処理装置の概略図である。
【図３】図１に示す基板検出装置の制御構成を示す模式図である。
【図４】図１に示す基板検出装置において、複数の受信器が基板収納容器高さ方向に沿って直列的に配列されている様子を示す模式図である。
【図５】図１に示す基板検出装置の受信器であるＰＳＤ素子の構成を説明する概略図である。
【図６】図１に示す基板検出装置において、基板が正常な状態で基板収納容器の溝に収納されている場合に検出される受信器出力の分布を示す図である。
【図７】図１に示す基板検出装置において、基板が複数枚重ねの状態で基板収納容器の溝に収納されている場合に検出される受信器出力の分布を示す図である。
【図８】図１に示す基板検出装置において、基板が斜め差しの状態で基板収納容器の溝に収納されている場合に検出される受信器出力の分布を示す図である。
【図９】基板が基板収納容器の溝から開口側に飛び出すようにしてずれてしまい少し傾いている状態（飛び出し状態）を説明する図である。
【図１０】図１に示す基板検出装置において、基板が正常な状態で基板収納容器の溝に収納されている場合（図１０（ａ））に検出される受信器出力の分布と、飛び出し状態で収納されている場合（図１０（ｂ））に検出される受信器出力の分布とをそれぞれ示す図である。
【図１１】図１に示す基板検出装置による基板の収納状態を検出する処理フローについて説明する図である。
【図１２】基板が傾いて収納されている場合の信号経路を説明する図である。
【図１３】変形例に係る基板検出装置を説明する図であって、基板が傾いて収納されている場合に検出される受信器の強度出力及び位置出力の分布を示す図である。
【図１４】図１３の検出例に対応する基板の収納状態を説明する図である。
【図１５】変形例に係る基板検出装置を説明する図であって、基板が傾いて収納されている場合に検出される受信器の強度出力の位置出力に対する分布を示す図である。
【図１６】変形例に係る基板検出装置を説明する図である。
【図１７】変形例に係る基板検出装置を説明する図である。
【図１８】変形例に係る基板検出装置を説明する図である。
【図１９】ＦＯＵＰにおける基板の収納状態を説明する図である。
【図２０】ＦＯＵＰ内に基板が収納されている状態を示す斜視図である。
【符号の説明】
１　基板検出装置
５　遮蔽板駆動装置
５ａ　遮蔽板
１１　ＦＯＵＰ
１１ａ　容器
１１ｃ　開口
１１ｄ　溝
５１　発信器
５２　受信器
５３　アーム
５９　部材
６６　基板検出モジュール
Ｗ　基板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a substrate detection device that detects the presence or absence of a substrate stored in a substrate storage container.
[0002]
[Prior art]
2. Description of the Related Art When a substrate such as a semiconductor wafer is transported in a semiconductor product manufacturing process or the like, a plurality of substrates are usually stored in a substrate storage container (hereinafter, referred to as a "cassette") and transported between each process. The required processing is performed for each cassette. In this case, it is necessary to first grasp the storage state of the substrate for each cassette before processing by the substrate processing apparatus. Therefore, in a substrate processing apparatus that processes a substrate stored in a cassette, a substrate detection device that detects the presence or absence of a substrate is provided (for example, see Patent Document 1).
[0003]
In the substrate detection device described in Patent Document 1, a cassette called an open cassette is used as a cassette for storing a plurality of substrates. An opening for inserting and removing a substrate is provided on the front side of the open cassette (hereinafter, simply referred to as “cassette”), and an opening smaller than the opening is provided on the back side of the cassette. I have. A plurality of grooves are formed in the cassette for holding the substrate substantially horizontally. In order to grasp in advance the substrate storage state in such a cassette before substrate processing, a substrate detecting means is provided in the cassette mounting portion. The substrate detecting means is a transmission type sensor composed of a light emitting element and a light receiving element which are arranged to face each other so as to sandwich the cassette from the front and rear, and this transmission type sensor is disposed from the uppermost groove in the cassette to the lowermost one. By moving the substrate up and down to the groove, the presence or absence of the substrate stored in each groove in the cassette is grasped.
[0004]
However, with the recent increase in the size of substrates, new standards have been negotiated for cassettes for storing the substrates. A cassette conforming to this standard is called a FOUP (front opening unified pod). The FOUP is provided with only one opening for inserting and removing a substrate, and a detachable lid is attached to this opening.
[0005]
In the above-mentioned FOUP, since there is only one opening, it is possible to detect the presence or absence of a substrate housed in each groove of the cassette by a transmission type sensor sandwiching the cassette from the front and rear as disclosed in Patent Document 1. Can not. For this reason, in order to detect the substrate, an operation of once opening the lid attached to the opening is absolutely necessary, so that the operation for detecting the substrate is complicated, and the detection device is likely to be complicated. And it is difficult to perform accurate detection.
[0006]
In order to alleviate such restrictions, after opening the lid of the FOUP, while lowering and retracting the mechanism for removing the lid, a sensor consisting of a pair of light emitter and receiver mounted on this mechanism, A device that detects the presence / absence of a substrate by blocking light in this order is disclosed (for example, see Patent Document 2).
[0007]
[Patent Document 1]
JP-A-3-297156
[Patent Document 2]
US Patent No. 6,188,323
[0008]
[Problems to be solved by the invention]
However, also in the device described in Patent Document 2, it is necessary to attach sensors on the light emitting side and the light receiving side to the mechanism for removing the lid, and it is inevitable that the substrate detecting device is complicated to some extent.
[0009]
In addition, since the light-emitting device and the light-receiving device detect the substrate while moving together, the detection operation is likely to be unstable, and a high-precision detection device capable of performing more stable and accurate detection has been developed. It is in a situation that is required.
[0010]
Furthermore, there is a problem that it is difficult to detect properly when the substrate is stored in an irregular state. FIG. 20 shows a part of the cassette 100 as viewed from the opening 101 side together with the substrate 102 held and accommodated in each groove, but the substrates 102a, 102d, 102e, and the gaps 103a to 103c are: The presence or absence of a substrate can be detected. However, in the case of a two-layered substrate 102b (or three or more layers) or an obliquely inserted (stepped, cross-slot) 102c, the light-emitting device and the light-receiving device are blocked while moving simultaneously. Therefore, it is difficult to properly detect the storage state.
[0011]
The present invention has been made in view of the above circumstances, and has as its object to provide a high-precision substrate detection device capable of accurately detecting the storage state of a substrate in a FOUP with a simple device configuration. .
[0012]
[Means for Solving the Problems]
In order to solve the above problem, the substrate detecting device according to claim 1 includes an opening for inserting and removing a substrate, and a plurality of grooves for storing and holding the inserted plurality of substrates substantially horizontally. A substrate detection device for detecting a stored substrate with respect to a substrate storage container provided in a step, which is attached to a member facing the opening, and is serially arranged along a height direction of the substrate storage container. A plurality of receivers arranged, and a transmitter that is installed so as to be movable in the vertical direction of the substrate storage container and emits a signal toward a substrate stored in each groove of the substrate storage container, The presence / absence and state of the substrate stored in each groove of the substrate storage container are detected by receiving a signal emitted from a transmitter by the receiver.
[0013]
According to this configuration, a plurality of receivers are arranged and mounted in series on a member facing the opening of the substrate storage container, and only the transmitter moves up and down to detect the substrate. The signal emitted from the container can be received, and the stored state of the substrate in the FOUP can be accurately detected. Also, since only the transmitter moves up and down, the mechanism of the substrate detecting device can be simplified. By arranging a plurality of receivers in series, there is no need to create an integrated long receiver, and a board detection device that detects the board by moving only the transmitter up and down can be easily realized. it can. Therefore, it is possible to obtain a high-precision detection device capable of accurately detecting the storage state of the substrate in the FOUP with a simple device configuration.
[0014]
According to a second aspect of the present invention, in the substrate detecting device according to the first aspect, the transmitter moves forward and backward into the substrate storage container with respect to a shielding plate driving device that advances and retreats and moves up and down the shielding plate that opens and closes the opening. It is attached so as to be able to detect the presence or absence and state of the substrate by blocking a signal path from the transmitter to the receiver by the substrate.
[0015]
According to this configuration, the substrate is detected by blocking the signal path formed between the transmitter that has advanced into the substrate storage container and the receivers arranged in series by the substrate. Therefore, reliable and accurate substrate detection can be performed.
In addition, the transmitter is attached to the shielding plate driving device, and the board is detected together with the raising and lowering operation of the shielding plate driving device, so that quick detection is possible, and a vertical moving mechanism for the transmitter is separately provided. There is no need to provide them, and the mechanism of the substrate detection device can be simplified.
[0016]
The substrate detection device according to claim 3, wherein the plurality of receivers are configured such that each receiver corresponds to each groove of the substrate storage container or each receiver corresponds to the substrate. It is characterized in that it is provided so as to correspond to a plurality of steps of each groove in the storage container.
[0017]
According to this configuration, the storage state of the substrate in each groove can be accurately detected, and a plurality of receivers can be efficiently arranged without waste.
[0018]
The substrate detecting device according to claim 4, wherein the irradiation diameter of the linear light emitted as a signal from the transmitter is reduced by a light collecting unit in the receiver according to any one of claims 1 to 3, so that The line light having the reduced diameter is emitted toward the light source.
[0019]
According to this configuration, it is easy to form a stable line light path from the transmitter to the receiver, the accuracy of receiving the line light emitted from the transmitter is improved, and the storage state of the substrate in the FOUP is improved. Can be detected accurately.
[0020]
The substrate detecting device according to claim 5, wherein the path of the line light emitted as a signal from the transmitter to the receiver is a line light reflecting unit or a line light. The irradiation angle of the linear light to the receiver is adjusted by changing the angle using the refraction means or the linear light guiding means.
[0021]
According to this configuration, the irradiation angle of the linear light to the receiver can be easily adjusted, and the receiving accuracy of the linear light can be improved.
[0022]
The substrate detection device according to claim 6, according to any one of claims 1 to 5, based on a receiver output by a signal received by the receiver, for each groove of the substrate storage container, The total width of the reception signal corresponding to the distribution length of the receiver output calculated in correspondence with the position of the transmitter moving along the height direction of the substrate storage container, and reaches the receiver by the substrate. Calculates a reception signal cutoff width corresponding to the length of the portion where the signal was not received in the entire reception signal width by blocking the signal path, and based on the size of the signal receivable width in each of the receivers. By comparing a predetermined threshold value to be set with the entire width of the reception signal, and comparing a predetermined threshold value to be set based on the size of the substrate with the reception signal cutoff width, the received signal is accommodated in each of the grooves. The storage state of the substrate Wherein the determining.
[0023]
According to this configuration, by calculating the reception signal cutoff width and comparing it with a predetermined threshold value, it is possible to detect a state in which a plurality of substrates are housed in a stack, and calculate the entire reception signal width. By comparing with a predetermined threshold value, it is possible to detect a state in which the board is stored obliquely. Therefore, it is possible to accurately detect an irregular substrate storage state.
[0024]
According to a seventh aspect of the present invention, in the substrate detecting device according to any one of the first to fifth aspects, the receiver can detect a strength of a received signal and a reception position of the received signal in the receiver. The receiver outputs an intensity output corresponding to the intensity of the signal received by the receiver and a position output corresponding to the reception position, or calculates the intensity output and the position output. Outputs information of a possible state, and based on the intensity output and the position output by the signal received by the receiver, for each groove of the substrate storage container, along the substrate storage container height direction. The total width of the received signal corresponding to the distribution length of the intensity output corresponding to the position of the transmitter that is moving during the movement, and the signal path reaching the receiver by the substrate is blocked by the received signal. The transmission in the overall width And a reception signal cutoff width corresponding to a length of a portion where the signal is not received, which is received through only one linear path from the receiver, is calculated based on a dimension of a signal receivable width in each of the receivers. By comparing a predetermined threshold value to be set with the entire width of the reception signal, and comparing a predetermined threshold value to be set based on the size of the substrate with the reception signal cutoff width, the received signal is accommodated in each of the grooves. The storage state of the substrate is determined.
[0025]
According to this configuration, it is possible to remove the signal reflected and received on the surface of the substrate, and calculate the entire reception signal width and the reception signal cutoff width. This makes it possible to accurately evaluate the tilt state of the substrate regardless of the influence of the difference in reflectance even when substrates having significantly different reflectances on the substrate surface coexist. Then, by comparing the reception signal cutoff width with a predetermined threshold value, it is possible to detect a state in which a plurality of substrates are stored in a stack, and by comparing the entire reception signal width with the predetermined threshold value, the substrate is stored obliquely. Status can be detected. Therefore, even if substrates having different reflectances on the substrate surface are mixed in the substrate storage container, the stored state of the substrate can be accurately detected.
[0026]
The substrate detecting device according to claim 8 is the device according to any one of claims 1 to 5, wherein the receiver can detect a strength of a received signal and a reception position of the received signal in the receiver. The receiver outputs an intensity output corresponding to the intensity of the signal received by the receiver and a position output corresponding to the reception position, or calculates the intensity output and the position output. Outputs information of a possible state, based on the intensity output and the position output by a signal received by the receiver when the transmitter moves along the substrate storage container height direction, For each groove of the substrate storage container, the overall width of the received signal corresponding to the distribution length of the intensity output corresponding to the position output, and the signal path to the receiver is blocked by the substrate. To the overall width of the received signal And a reception signal cutoff width corresponding to a length of a portion where the signal received through only one linear path from the transmitter is not received, and a signal reception width in each of the receivers is calculated. By comparing a predetermined threshold set based on the size of the received signal with the entire width of the reception signal, and comparing a predetermined threshold set based on the size of the substrate with the reception signal cutoff width, the respective grooves are formed. The storage state of the substrate stored in the storage device is determined.
[0027]
According to this configuration, it is possible to remove the signal reflected and received on the surface of the substrate, and calculate the entire reception signal width and the reception signal cutoff width. This makes it possible to accurately evaluate the inclination state of the substrate regardless of the influence of the difference in the reflectance even when there is a substrate having a significantly different reflectance on the substrate surface. Then, by comparing the reception signal cutoff width with a predetermined threshold value, it is possible to detect a state in which a plurality of substrates are stored in a stack, and by comparing the entire reception signal width with the predetermined threshold value, the substrate is stored obliquely. Status can be detected. Therefore, even if substrates having different reflectances on the substrate surface are mixed in the substrate storage container, the stored state of the substrate can be accurately detected.
[0028]
The substrate detection device according to claim 9, according to any one of claims 1 to 5, based on a receiver output by a signal received by the receiver, for each groove of the substrate storage container, The total width of the reception signal corresponding to the distribution length of the receiver output calculated in correspondence with the position of the transmitter moving along the height direction of the substrate storage container, and reaches the receiver by the substrate. There is a reception signal cutoff width corresponding to the length of the portion where the signal was not received in the entire reception signal width by blocking the signal path, and a center of the receiver signal cutoff width in the entire reception signal width. The received signal cutoff position corresponding to the position is calculated, and a predetermined threshold value set based on the board size and the cutoff position is compared with the received signal cutoff width, based on the dimension between the grooves. Set By comparing the constant threshold value and the reception signal cutoff width, characterized in that to determine the storage state of said substrate accommodated in the grooves.
[0029]
According to this configuration, by calculating the reception signal cutoff width and comparing it with a predetermined threshold value, it is possible to detect a state in which a plurality of substrates are housed in a stack, and calculate the entire reception signal width. By comparing with a predetermined threshold value, it is possible to detect a state in which the board is stored obliquely. That is, it is possible to accurately detect an irregular substrate storage state. Then, by comparing the reception signal cutoff width with a predetermined threshold value set based on the reception signal cutoff position, the FOUP is shifted from each groove toward the opening side and is stored slightly inclined, but is stored normally. It is possible to accurately detect even a delicate storage state that may be judged to be the same.
[0030]
The substrate detection device according to claim 10, wherein, in any one of claims 1 to 9, the plurality of receivers arranged in series along the height direction of the substrate storage container are at least adjacent to each other. A distance corresponding to the length of the portion where the receiver is not provided between the receivers is provided so as to be movable in the height direction of the substrate storage container.
[0031]
According to this configuration, the transmitter is temporarily moved up and down to detect the stored state of the substrate, and then the receiver is moved up and down by a distance corresponding to the length of the portion where the receiver is not disposed between adjacent receivers. And the transmitter is moved up and down again to detect the stored state of the substrate. Then, by superimposing these receiver outputs based on the signals received by the receiver, it is possible to obtain the same receiver output as when there is no portion where the receiver is not provided. Therefore, the storage state of the substrate in each groove can be accurately detected, and the plurality of receivers can be efficiently arranged without waste.
[0032]
The substrate detection device according to claim 11, wherein the plurality of receivers arranged in series along the height direction of the substrate storage container are the same as the substrate storage container height according to any one of claims 1 to 9. It is characterized by being arranged in a plurality of rows along the vertical direction.
[0033]
According to this configuration, the receivers arranged in a plurality of rows can be arranged such that the positions of the receivers in the substrate storage container height direction are shifted from each other. As a result, even if there is a portion where a receiver is not provided in one receiver row, a state where the receiver is provided in another receiver row at a position corresponding to the portion. Can be Therefore, the storage state of the substrate in each groove can be accurately detected, and the plurality of receivers can be efficiently arranged without waste.
[0034]
The substrate detection device according to claim 12, according to claim 11, by splitting a path of the linear light emitted as a signal from the transmitter to the receiver by using a half mirror, thereby forming the plurality of rows. A line light is emitted toward each of the receivers arranged.
[0035]
According to this configuration, even when a plurality of receivers arranged in series are arranged in a plurality of rows, one transmitter simultaneously transmits each receiver row arranged in a plurality of rows. It can emit linear light. Therefore, the device configuration can be simplified.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a state in which a substrate detection apparatus 1 according to the present embodiment is attached to a part of a substrate processing apparatus 50. FIG. 1A is a top view, and FIG. () Is a diagram viewed from the substrate processing apparatus 50 side. FIG. 3 is a schematic diagram illustrating a control configuration of the substrate detection device 1. FIG. 2 is a diagram illustrating a schematic configuration of a substrate processing apparatus 50 in which the substrate detection apparatus 1 is used.
[0037]
First, in FIG. 2, an outline of a substrate processing apparatus 50 using the substrate detection apparatus 1 will be described. In FIG. 2, the substrate processing apparatus 50 is illustrated as a side view including a partial cross section. The substrate processing apparatus 50 is a substrate processing apparatus corresponding to a substrate storage container called a FOUP (front opening unified pod) in which a lid is attached to an opening for inserting and removing a substrate.
[0038]
The substrate processing apparatus 50 takes out the substrate W from the FOUP 11 (hereinafter, referred to as a “cassette 11”), performs a predetermined process on the substrate W (not shown in detail), and a cassette on which the cassette 11 is placed. The mounting section 3 on which the stage 2 is provided is configured to be separated by a partition wall 10. The partition 10 is provided with a passage port 10a at a position corresponding to each cassette stage 2, and has a shielding plate 5a (hereinafter, referred to as a "shutter 5a") that opens and closes the passage 10a. 5 ”) and a substrate transfer device 8 are further provided between the partition wall 10 and the processing unit 9.
[0039]
Here, the cassette 11 is exemplified in FIG. 19, and includes a container 11a for storing the substrate W and a lid 11b which is detachably fitted into an opening 11c provided in the container 11a. On the inner wall of the container 11a, a multi-stage groove 11d is provided so as to oppose, and the substrate W is housed in each groove 11d while being held substantially horizontally. A fixing mechanism 11e for fixing the lid 11b to the container 11a is embedded in the lid 11b. The fixing mechanism 11e includes two lock members 11f each having a cut rack and a rotatable pinion 11g that meshes with the rack. Be composed. The rotation of the pinion 11g causes the lock member 11f to protrude from the lid 11b, thereby fixing the container 11a and the lid 11b.
[0040]
Again, in FIG. 2, the cassette stage 2 is configured to be able to advance and retreat in the direction of the partition 10 (Y direction) by the cassette driving mechanism 4 provided below the cassette stage 2. Then, the cassette driving mechanism 4 is configured to drive a screw shaft 4b screwed to a convex portion 2a provided on the lower surface of the cassette stage 2 by an electric motor 4a. When the cassette 11 is placed on the cassette stage 2, the electric motor 4 a rotates the screw shaft 4 b forward to move the cassette stage 2 toward the partition 10. When the processing of all the substrates W in the cassette 1 is completed, the electric motor 4a rotates the screw shaft 4b in the reverse direction to move the cassette stage 2 backward.
[0041]
The above-described passage opening 10 a is formed in the partition 10 at a position facing the cassette 11 so as to be substantially the same size as the cassette 11. The passage opening 10a is for taking out and storing the substrate W from the cassette 11, and excluding the atmosphere between the processing unit 9 and the mounting unit 3 except when the substrate W is loaded and unloaded from the cassette 11. It is closed by a shutter 5a to shut off.
[0042]
The transmitter 51 of the substrate detecting device 1 according to the present embodiment is attached to the shutter 5a of the shutter driving device 5, and the shutter 5a is attached to the lifting mechanism 5c by the support member 5b. The substrate detecting device 1 will be described later in detail.
The support member 5b is formed in the shape of an L-shaped arm extending downward. The support member 5b is driven up and down in the Z direction by an elevating mechanism 5c to which the base end of the support member 5b is attached, and further supports the elevating mechanism 5c. It is driven forward and backward in the Y direction by the forward and backward mechanism 5d.
[0043]
The elevating mechanism 5c is configured by a so-called screw feed mechanism that drives a screw shaft screwed to the base end of the support member 5b by an electric motor. The reciprocating mechanism 5d is also configured by a screw feed mechanism that moves the elevating mechanism 5c forward and backward in the Y direction. That is, the arrow (a) in FIG. 2 indicates the moving direction and the arrow (b) indicates the moving direction. FIG. 2 shows the state of the shutter 5a before and after the vertical movement after the lid 11b of the cassette 11 is removed.
[0044]
A substrate transfer device 8 is provided between the shutter driving device 5 and the processing unit 9. The substrate transport device 8 takes out the substrate W from the cassette 11 after the substrate detecting device 1 detects the storage state of the substrate W in the cassette 11 as described later and transfers the substrate W to the processing unit 9. After the above process is completed, the substrate W is further received and stored in the cassette 11 again. The substrate transfer device 8 has an arm 8a for holding the substrate W, and the arm 8a is configured to be able to advance and retreat in a horizontal plane by a screw feed mechanism provided on the arm support 8b. The arm support 8b is connected to and supported by an output shaft of a motor built in the arm turntable 8c. The rotation of the electric motor allows the arm 8a to rotate in a horizontal plane. Further, the arm turntable 8c can be moved up and down by an elevating mechanism 8d constituted by a screw feed mechanism. The lifting mechanism 8d is mounted on a slide mechanism 8e that can slide in the X direction in the figure.
[0045]
The above is the description of the substrate processing apparatus 50 in which the substrate detection apparatus 1 is used. The storage state of the substrate W in the cassette 11 is detected by the substrate detection apparatus 1 described later, and the cassette 11 First, the processing of the substrate W is performed.
[0046]
Hereinafter, the substrate detection device 1 according to the present embodiment will be described. As shown in FIGS. 1 to 3, the substrate detection device 1 includes a transmitter 51 that emits a beam (line light) as a signal, and a plurality of receivers 52 that receive a signal emitted from the transmitter 51. are doing. The transmitter 51 is attached via an arm 53 to a shutter driving device 5 that moves the shutter 5a that opens and closes the opening 11c by removing the lid 11b of the cassette 11 and moves up and down. The arm 53 is swingably mounted at an upper end of the shutter 5a at one end 53a, and a transmitter 51 is mounted at the other end 53b.
[0047]
After the arm 53 swings and swings as described later to advance into the opening 11c of the cassette 11, the transmitter 51 outputs a signal (line light) toward the substrate W stored in each groove 11d of the cassette 11. And this signal can be received by a receiver 52 described later. Further, since the signal path S from the transmitter 51 to the receiver 52 is blocked by the substrate W, the presence or absence and the state of the substrate W are detected as described later. In addition, as the transmitter 51, an LD (laser diode), an LED (light emitting diode), or the like can be used.
[0048]
FIG. 1 shows a mechanism for turning and swinging the arm 53 to which the transmitter 51 is attached. In this drawing, one end 53a of an arm 53 serving as a swing center is attached to a swing shaft 54 rotatably supported via a bearing, and a side of the swing shaft 54 to which the arm 53 is attached is described. A link member 55a is attached to the opposite end, and the other end of the link member 55a is swingably attached to the link member 55b. The other end of the link member 55b is swingably attached to a rod 57 provided on the air cylinder 56. With these configurations, by switching the compressed air supplied to the air cylinder 56 to move the rod 57 back and forth, the swing shaft 54 is driven to rotate only a predetermined rotation angle via the link members 55b and 55a, and the arm 53 swings, and the transmitter 51 advances and retreats into the cassette 11. That is, when the rod 57 projects from the air cylinder 56, the transmitter 51 advances into the cassette 11 through the opening 11c.
[0049]
As described above, when the transmitter 51 advances into the cassette 11, the state of the substrate W can be detected by the signal path S formed between the transmitter 51 and the receiver 52. Further, since the transmitter 51 is mounted on the upper part of the shutter 5a, the transmitter 51 moves up and down in accordance with the up and down movement of the shutter 5a, and the substrate W stored in each groove 11d of the cassette 11 is moved by the shutter. With the lowering of 5a, detection can be performed sequentially.
[0050]
A stopper 58 is provided above the shutter 5a near the one end 53a of the arm 53. The stopper 58 controls the turning range of the arm 53 by abutting on the side surface of the arm 53 when the transmitter 51 advances into the cassette 11, and positions the transmitter 51. Accordingly, a minute variation in the position that occurs when the rod 57 is driven by the air cylinder 56 can be suppressed, and the transmitter 51 can be accurately positioned.
[0051]
Next, the receiver 52 will be described. As shown in FIGS. 1 and 2, when the cassette 11 is placed on the cassette stage 2 and the opening 11 c thereof faces the passage opening 10 a of the partition 10, the member 59 is positioned so as to face the opening 11 c. , A plurality of receivers 52 are attached. The plurality of receivers 52 are arranged in series along the height direction of the cassette 11. A state in which the plurality of receivers 52 are arranged in series is shown in the schematic diagrams of FIGS. As shown in these drawings, the plurality of receivers 52 are provided such that each receiver 52 corresponds to each groove 11d of the cassette 11. Accordingly, the signal S emitted while the transmitter 51 moves up and down (moves in the direction of the arrow in the figure) is received by each receiver 52 (see FIG. 11), and the storage state of the substrate W in each groove 11d is described later. Will be grasped as if to. The receiver 52 may be a photo diode (PD), a position sensitive detector (PSD), a charge coupled device (CCD), or the like. When a PSD or a CCD is used as an element for the receiver, the incident position of the light beam in the receiver can be detected.
[0052]
Hereinafter, a case where a PSD element is used as the receiver 52 will be described as an example.
FIG. 5 is a schematic diagram illustrating a configuration of a receiver 52 (hereinafter, also referred to as “PSD 52”) including a PSD element. In the PSD 52, electrodes 52b and 52c are formed at both ends of the light receiving surface 52a. Then, from the electrodes (52a, 52b), electrode signals I1, I2 are output which are inversely proportional to the incident position of the signal (line light) and the distance between the electrodes. FIG. 5 illustrates a case where a signal is incident on a position shifted by a distance Xm downward from the center position of the PSD 52 in the cassette height direction.
[0053]
In the PSD 52, the sum I (I = I1 + I2) of I1 and I2 is proportional to the intensity of the incident signal (the intensity of the linear light). Then, the incident position Xm can be obtained by the following equation (1).
[0054]
(Equation 1)

[0055]
Here, Lx is the element length of the PSD 72 (the distance between the electrodes 72a and 72b).
Therefore, the receiver 72 can detect the strength of the received signal and the reception position of the received signal in the receiver 72. The receiver 72 can output an intensity output I corresponding to the intensity of the signal received by the receiver 72 and a position output Xm corresponding to the reception position, or the intensity output I and the position output It is possible to output information (electrode signals I1 and I2) in a state where the output Xm can be calculated.
[0056]
As described above, in the substrate detection device 1, the plurality of receivers 52 are mounted in series on the member 59 facing the opening 11c of the cassette 11, and only the transmitter 51 moves up and down. Since the substrate W is detected, a signal emitted from the transmitter 51 can be stably received, and the storage state of the substrate in the cassette 11 can be accurately detected. Further, only the transmitter 51 moves up and down, and furthermore, it moves while being attached to the shutter 5a, so that the mechanism of the substrate detecting device can be simplified. And, by arranging the plurality of receivers 52 in series, there is no need for the trouble of manufacturing an integrated long receiver, and a substrate detection device that detects the substrate W by moving only the transmitter 51 up and down is not required. It can be easily realized.
[0057]
Next, a control configuration for detecting the substrate W by the substrate detection device 1 will be described with reference to FIG. FIG. 3 schematically shows the relationship among the transmitter 51, the receiver 52, the substrate W, the shutter 5a and its supporting member 5b, the screw shaft 61, the stepping motor 60, and the like. The transmitter 52 is moved up and down by a stepping motor 60 and a screw shaft 61 via a shutter 5a and a support member 5b.
[0058]
In FIG. 3, the substrate detection device 1 has a receiver controller 63, a transmitter movement controller 64, a transmitter controller 65, and a substrate detection module 66. The receiver controller 63 processes a signal received by the receiver 52 (hereinafter, also referred to as “PSD 52”). The transmitter movement controller 64 controls the movement position of the transmitter 51 (hereinafter, also referred to as “LD51”) by controlling the stepping motor 60. The transmitter controller 65 controls on / off switching of a beam emitted from the LD 51 and control of its output. The board detection module 66 is communicably connected to each of these controllers (63, 64, 65), and grasps the storage state of the board W in each groove 11d, as described later.
[0059]
First, in the board detection module 66, at the timing when the retracting mechanism 5d of the shutter driving device 5 retreats the shutter 5a and removes the lid 11b of the cassette 11 (see FIG. 2), the compressed air to the air cylinder 56 is released. A switching command is transmitted to an electromagnetic valve 67 for switching the supply. Thus, the rod 57 advances with respect to the air cylinder 56, and the LD 51 advances into the cassette 11 (see FIG. 1).
[0060]
When the arm 53 is turned and the LD 51 advances into the cassette 11, the substrate detection module 66 transmits a pulse command to the transmitter movement controller 64 and transmits a beam irradiation command to the transmitter controller 65. Thereby, a beam (signal) is emitted from the LD 51, and the transmitter movement controller 64 drives the stepping motor 60 in accordance with the received pulse command, and the screw shaft 61 rotates with the rotation of the motor 60. Then, the LD 51 starts moving down together with the shutter 5a.
[0061]
As the LD 51 descends, the beams emitted from the LD 51 are sequentially received by each PSD 52. At this time, if the substrate W is stored in each groove 11d of the cassette 11, the path S (signal path) of the beam from the LD 51 to the PSD 52 is blocked in the portion where the substrate W exists. Then, a receiver output (PSD output) based on the signal received by the PSD 52 is transmitted to the board detection module 66 by the receiver controller 63.
[0062]
The receiver controller 63 receives the electrode signals I1 and I2 from each PSD 52, and calculates the intensity output I which is the sum of the electrode signals I1 and I2 and the position output Xm which can be obtained from the above-described equation (1). . Then, the receiver controller 63 transmits the intensity output I and the position output Xm to the substrate detection module 66. Therefore, as the receiver output (PSD output), the intensity output I and the position output Xm are transmitted from the receiver controller 63 to the substrate detection module 66. Note that the receiver controller 63 may calculate only the intensity output I without calculating the position output Xm, and transmit only the intensity output I to the substrate detection module 66 as a receiver output.
[0063]
Based on the obtained PSD output, the substrate detection module 66 associates the position of the LD 51 moving along the height direction of the cassette 11 with the position of the LD 51 (that is, the distribution of the PSD output totaled in correspondence with the pulse command). Is obtained for each PSD 52 (that is, for each groove 11d of the cassette 11). FIG. 6 shows the distribution of the PSD output in each PSD 52 detected when the substrate W is stored in each groove 11d in a normal state. FIG. 6 shows the distribution of the intensity output I as the distribution of the PSD output. When the substrate W is in the normal storage state, as shown in FIG. 6, the relationship between the PSD output (vertical axis) as the intensity output I and the position (horizontal axis) of the LD 51 is a one-dimensional array type output distribution. You can ask. Then, it is possible to calculate the whole reception signal width C (hereinafter, also referred to as “the whole PSD C” or “the whole width C”) corresponding to the obtained distribution length of the PSD output. Further, the signal path S leading to the PSD 52 is blocked by the substrate W, so that the received signal cutoff width D (hereinafter, referred to as “cutoff width D” or “cutoff width D”) corresponding to the length of the portion where the beam is not received in the entire PSD C of the PSD. Light-shielding width D ") can also be calculated. When the substrate W is not stored in the groove 11d, the cutoff width D does not occur.
[0064]
Since the value of the cutoff width D is determined by the thickness of the substrate W, as shown in FIG. 7, when the plurality of substrates W are stacked in the groove 11d, the cutoff width is smaller than in the normal state (FIG. 6). D is required as a spread state. The number of substrates W accommodated in the same groove 11d can be grasped from the value of the widened interruption width D. In the substrate detection module 66, a predetermined threshold value Dv (hereinafter, also referred to as “known substrate width Dv”) set in advance based on the dimensions of the substrate W (substrate thickness) and the like, and the calculated cutoff width D are compared. Thus, it is possible to detect a state in which a plurality of substrates W stored in each groove 11d are stored in a stack.
[0065]
Further, in a state where the substrate W is stored obliquely (stepped, cross slot), as shown in FIG. 8, the entire width C is determined to be smaller than that in the normal state (FIG. 6) (FIG. 8). In the figure, a portion narrowed from the entire width C in a normal state is indicated by a dotted line). The value of the reduced overall width C makes it possible to grasp the state of the oblique insertion. In the board detection module 66, the signal receivable width (the maximum width of the PSD output distribution, which is substantially equal to the entire PSD width C when the board W is normally housed) in each PSD 52 is determined based on the dimension. By comparing a predetermined threshold value Cv set in advance (hereinafter also referred to as “known PSD width Cv”) with the obtained overall width C calculated as the distribution length of the PSD output, the value of the overall width C is calculated. If there is no change with respect to the value of the known PSD width Cv, it is determined that the substrate W is not accommodated obliquely. As described above, the board detection module 66 can determine and detect the state in which the board W is stored obliquely by comparing the known PSD width Cv with the entire width C.
[0066]
When the lid 11b of the cassette 11 is opened by the shutter 5b, the substrate W may be displaced so as to protrude from each groove 11d of the cassette 11 toward the opening 11c, and may be slightly tilted. That is, as shown in FIG. 9, there is a case where the storage device is tilted and stored while being slightly protruded toward the opening 11 c side (from a normal position indicated by a solid line to a protruded state indicated by a dotted line). However, although stored in such a protruding state, if it is possible to perform a take-out operation with the substrate transfer device 8 (see FIG. 2), it can be safely determined that the storage state is normal.
[0067]
When the substrate W is located at the normal position in FIG. 9, a PSD output distribution having a waveform as shown in FIG. 10A is obtained, the value of the cutoff width D is also substantially the same, and the cutoff is performed in the entire width C. The position where the width D exists (the position G where the center of the cutoff width D is found from the predetermined reference point O in FIG. 10) is also substantially the same position. However, when the substrate W is in the protruding state in FIG. 9, a PSD output distribution having a waveform as shown in FIG. 10B is obtained. That is, the position G where the center of the cutoff width D exists is different from the case where the position is the normal position, and the width of the cutoff width D is also different from the case where the position G is also the normal position.
[0068]
It is desirable to accurately detect even such a delicate storage state in which it is possible to determine that the storage state is normal even though the storage state is slightly inclined. Therefore, the board detection module 66 calculates the received signal cutoff position G corresponding to the position where the center of the cutoff width D exists in the entire width C, in addition to the above-described received signal entire width C and received signal cutoff width D. Then, the above-mentioned predetermined threshold value (known substrate width) Dv is set based on the dimensions of the substrate W and the calculated interruption position G, and the known substrate width Dv set according to the interruption position G is compared with the interruption width D. By doing so, even when the PSD output distribution as shown in FIG. 10B is obtained, it is possible to grasp that the substrate W is in a protruding state. As a specific example of setting the known substrate width Dv according to the blocking position G, a method of changing the known substrate width Dv in proportion to the blocking position G as shown in the following equation (2) can be used.
[0069]
(Equation 2)

[0070]
However, K1 and K2 are constants set based on the positional relationship between each groove 11d and each PSD 52.
In addition, the known substrate width Dv may be set as a quadratic expression instead of a linear expression of the cutoff position G, may be set as a table value according to the value of the cutoff position G, or various methods may be selected.
[0071]
Next, a processing flow for detecting the stored state of the substrate W by the substrate detection device 1 will be described with reference to FIG. First, the LD 51 starts lowering while emitting a beam from the LD 51, and starts scanning the substrate W (S101). In the PSD 52, the beam emitted from the LD 51 is received in a portion where the substrate W does not exist, and the received PSD output is transmitted to the substrate detection module 66. Then, the board detection module 66 totals the PSD output together with the position information of the LD 52 (pulse command of the stepping motor 60) (S102).
[0072]
As described above, the board detection module 66 calculates the blocking width D (light blocking width D) and the overall width C for each PSD 52 based on the PSD output (S103). At this time, the PSD output may be processed as a binarized signal determined based on a predetermined threshold. Then, for each PSD output, it is determined whether or not light shielding exists in the entire width C (that is, whether or not the light shielding width D can be calculated as a non-zero value) (S104). If there is no shading in the PSD output to be determined, the overall width C is further compared with the above-mentioned known PSD width Cv (S105). If the value of the overall width C does not change from the value of the known PSD width Cv, it is determined that the substrate W does not exist in the groove 11d corresponding to the PSD output (S106). If there is a change, as described with reference to FIG. 8, it is determined that the camera is in an oblique insertion (cross slot) state (S111).
[0073]
If it is determined in the processing step S104 that the light shielding exists in the entire width C (when the light shielding width D is calculated), the light shielding width D is compared with the above-mentioned known substrate width Dv (S107). ). In this comparison, the value of the light-shielding width D is compared with the value of the known substrate width Dv (S108), and if the light-shielding width D is smaller than the known substrate width Dv, the groove 11d corresponding to the PSD output is placed in the groove 11d. It is determined that one substrate W is stored (that is, stored in a normal state) (S109). The value of the known substrate width Dv is set to a value that can determine a dimension larger than the thickness of one substrate and smaller than the thickness of two substrates. In addition, as described above, by setting the known substrate width Dv based on the cutoff position G, it is possible to detect a normal stored state that is a protruding state described with reference to FIG.
[0074]
In step S108, if the light-shielding width D is larger than the known substrate width Dv, whether a plurality of substrates W are stored in the groove 11d corresponding to the PSD output or whether the substrate W is in a cross slot state Is determined (S110). In step S105, the state of the cross slot is detected by judging a change in the overall width C. However, the position of the substrate W, the length of a portion (dead zone) where PSDs between adjacent PSDs are not arranged, and the PSD 52 Depending on the positional relationship between the groove and the groove 11d, there is a case where light is blocked even in the cross slot state (a case where the light blocking width D is generated). In this case, the light-shielding width D is further increased as compared to a state in which a plurality of substrates W are normally assumed. Therefore, this threshold value is set as a known plural substrate width, and the known plural substrate width is compared with the light shielding width D (W108) to determine whether the plural substrates are in a stacked state or a cross slot state. it can. That is, if the light-shielding width D is larger than the width of the known plurality of substrates, it is determined that the slot is in a cross slot state (S111), and the groove 11d corresponding to the PSD output is determined to have an abnormal substrate installation (S112). If the light-shielding width D is not larger than the width of the known plural substrates, it is determined that the plural substrates are superposed (S113), and the groove 11d corresponding to the PSD output is determined to be abnormal in the substrate installation (S114). ).
[0075]
By performing the above-described processing in the substrate detection module 66, the storage state of the substrates W in all the grooves 11d in the cassette 11 can be accurately detected, and irregularities such as stacking a plurality of substrates or oblique insertion can be achieved. It is possible to accurately grasp even the substrate storage state.
[0076]
Finally, the operation of the substrate detection device 1 according to the present embodiment will be described while omitting the above-described portions as appropriate. First, in FIG. 2, the cassette 11 transported by a transport facility (not shown) or the like is placed on the cassette stage 2 of the loading unit 3. After being placed, the cassette 11 is driven forward by the cassette drive mechanism 4. At this time, the shutter 5a blocks the passage opening 10a. When the cassette 11 moves to a position close to the shutter 5a, a lock mechanism (not shown) provided on the shutter 5a is connected to a pinion 11g of a fixing mechanism 11e provided on the lid 11b of the cassette 1. Then, the fixing mechanism 11e is released (see FIG. 19), and the lid 11b can be removed from the container 11a, and the lid 11b is held by the shutter 5a.
[0077]
Next, the shutter 5a is moved backward by the shutter moving mechanism 5d. By retreating, the opening 11c of the cassette 1 is opened, and a space is generated between the shutter 5a holding the lid 11b and the cassette 11.
Referring now to FIG. 1, the shutter 5a in a state after being retracted is shown, and the arm 53 before being swung by the air cylinder 56 and the rod 57 is shown by a solid line. From this state, the forward movement of the rod 57 with respect to the air cylinder 56 causes the arm 53 to swing through the link members (55a, 55b) and the swing shaft 54 to the position indicated by the two-dot chain line. The attached LD 51 advances into the cassette 11.
[0078]
When the LD 51 advances into the cassette 11, the LD 51 emits linear light toward the receiver 52. Then, as the shutter 5a is lowered by the elevating mechanism 5c of the shutter driving device 5, and scanning is performed between the LD 51 and the PSD 52, the signal path is blocked where the substrate W is present, Where W does not exist, the signal reaches the PSD 52 and is received without interruption of the signal path.
[0079]
Then, as the LD 51 descends, the output of each PSD 52 corresponding to the position of the moving LD 51 is sequentially obtained. When the LD 51 completes the passage of the lowermost groove 11d of the cassette 11 with the lowering of the shutter 5a, the outputs of all the PSDs 52 are obtained, and the substrate detection module 66 outputs the signals in the respective grooves 11d as described above. The storage state of the substrate W is detected, and the substrate storage information of the cassette 11 is obtained. Then, for example, when the processing of the cassette 11 is performed in the processing unit 9 of the substrate processing apparatus 1, the substrate W is taken out from the groove 11d to specify the cassette 11 based on the substrate storage information, and Further, it is used when the substrate W is returned and stored in the specific groove 11d from which it has been taken out.
[0080]
When the signal transmission for detecting the substrate W is completed in the cassette 11, the arm 53 retreats from the state of protruding to the passage opening 10a to the state shown by the solid line in FIG. 1 again.
[0081]
The above is the description of the substrate detection device 1 according to the present embodiment. According to the substrate detection device 1, with a simple device configuration, it is possible to accurately detect the storage state of the substrate in the FOUP with high accuracy. A detection device can be obtained.
[0082]
The embodiments are not limited to the above, and may be modified as follows, for example.
[0083]
(1) In the present embodiment, an example in which only the intensity output I is used as the PSD output (receiver output) to be counted in association with the position of the LD 71 (transmitter 71) moving along the height direction of the cassette 11 Has been described, but the totalization may be performed using both the intensity output I and the position output Xm.
[0084]
FIG. 12 is a diagram illustrating a signal path when the substrate W is inclined. When the substrate W is slightly inclined with respect to the optical axis of the transmitter 51 (the irradiation direction of the linear light), the signal emitted from the LD 51 not only reflects off the side surface of the substrate W but also blocks the surface of the substrate. It will be reflected and blocked. That is, when the signal is reflected by the surface of the substrate W, the signal path from the LD 51 to the PSD 52 is bent, and a signal is obliquely incident on the PSD 52. At this time, if the reflectance of the surface of the substrate W is high, as shown in FIG. 12A, the light is reflected on the surface of the substrate W, and the signal enters the PSD 52 with almost no attenuation. On the other hand, if the reflectance of the surface of the substrate W is low, the light is reflected on the surface of the substrate W as shown in FIG. As described above, when the reflectance of the surface of the substrate W is different, as shown in FIGS. 12A and 12B, even if the inclination angle of the substrate W is the same, it is calculated as the length of the portion where no signal is received. There is a case where the magnitude of the cutoff width D is greatly different. For this reason, when the substrates W accommodated in the cassette 11 include a substrate having a high reflectance and a substrate having a low reflectance, a predetermined threshold value to be compared with the cutoff width D to determine the accommodation state of the substrates W (Such as the known substrate width Dv) may not be set properly.
[0085]
Therefore, the board detection module 66 detects the intensity of the signal I received by the PSD 52 (receiver 52) and the position output Xm (outputs I and Xm calculated by the receiver controller 63) and outputs the cassette 11 For each groove 11d, a total reception signal width C1 corresponding to the distribution length of the intensity output I calculated in association with the position of the LD 51 (transmitter 51) moving along the height direction of the cassette 11 is calculated. . Similarly, for each groove 11d, the signal path to the PSD 52 is blocked by the substrate W, so that the signal received via only one linear path from the LD 51 in the entire width C1 (the surface of the substrate W A reception signal cutoff width D2 corresponding to the length of a portion where a signal that is not reflected and directly enters the PSD 52 from the LD 51 is not received is calculated.
[0086]
FIG. 13 is a diagram for explaining a method of calculating the overall width C1 and the cutoff width D2. The intensity output I and the position output Xm of the PSD 52, which are detected when the substrate W is stored in a tilted state, are output from the LD 51. It is a figure which shows the distribution aggregated corresponding to the position. FIG. 14 is a view for explaining a stored state of the substrate W corresponding to the detection example of FIG. FIG. 14 illustrates a state in which the substrate 52 is inclined so that the PSD 52 side of the substrate W is slightly lifted.
[0087]
The position output Xm of the PSD 52 with respect to the position of the LD 51 changes linearly when the signal enters straight without being interrupted by the substrate W, and has a distribution in a linear region shown in FIG. On the other hand, when the signal is blocked by the substrate W, the electrode signals I1 and I2 are not properly obtained, and the position output Xm cannot be calculated based on the equation (1). Therefore, when the intensity output I is smaller than a predetermined threshold value Iv (intensity threshold value Iv), the substrate detection module 66 ignores the position output Xm and processes as no data.
[0088]
When the signal is reflected and blocked on the surface of the substrate W, the signal path is bent on the surface of the substrate W. Therefore, in the example of FIG. 14, the signal incident position on the PSD 72 is opposite to the moving direction of the LD 51. Will move. Therefore, as shown in FIG. 13, the distribution of the position output Xm deviates from the distribution of the linear linear region, and becomes the distribution of the curved reflection region.
[0089]
Here, similarly to the present embodiment, when the substrate detection module 66 calculates the length of the portion where the intensity output I is equal to or less than the intensity threshold value Iv (corresponding to the length of the portion where no signal is received), the cutoff is performed. The length of the width will be calculated as D1. However, in consideration of the presence of the reflection area, the substrate detection module 66 determines the part where the intensity output I is equal to or less than the intensity threshold Iv and the part where the position output Xm is outside the linear area even if the intensity output I is equal to or greater than the intensity threshold Iv. To calculate the length D2.
[0090]
The determination as to whether or not the position output Xm is outside the linear region can be made based on a determination method M1 based on the following equation (3), a determination method M2 based on the following equation (4), and the like.
[0091]
[Equation 3]

[0092]
(Equation 4)

[0093]
The determination method M1 is a method of determining that the region is outside the linear region when the absolute value of Δ1 calculated by the above equation (3) exceeds a predetermined threshold. The LD position in the equation (3) is the coordinates of the LD position shown in FIG. 13, and A1 and A2 are constants.
[0094]
In addition, the determination method M2 calculates a difference Δ2 between the reference value of the position output Xm and the position output Xm measured in advance without the substrate W at the time of device adjustment or the like based on the equation (4). Is a method of judging that the region is outside the linear region when exceeds a predetermined threshold value set in advance.
[0095]
After calculating the overall width C1 and the cutoff width D2 as described above, the substrate detection module 66 then determines the stored state of the substrate W in the same procedure as in the present embodiment. That is, the board detection module 66 first compares the entire width C1 with a predetermined threshold value Cv (known PSD width Cv) set in advance based on the size of the signal receivable width in each PSD 52, and determines the size of the board W. Then, a predetermined threshold value Dv (known substrate width Dv) set in advance is compared with the cutoff width D2. Thereby, the storage state of the substrate W stored in each groove 11d is determined.
[0096]
As described above, according to the modified example described with reference to FIGS. 13 and 14, it is possible to calculate the overall width C1 and the cutoff width D2 by removing the signal reflected and received on the surface of the substrate W. This makes it possible to accurately evaluate the inclination state of the substrate W regardless of the influence of the difference in reflectance even when the substrates W having significantly different reflectances on the substrate surface coexist. Therefore, the same operational effects as those of the present embodiment can be obtained, and even if the substrates W having different reflectances on the substrate surface are mixed in the cassette 11, the stored state of the substrates W can be accurately detected.
[0097]
(2) In the case where the board detection module 76 is to sum up data using both the intensity output I and the position output Xm, a method different from the above-described modification may be selected. FIG. 15 is a diagram illustrating an example in which, when the substrate W in the state illustrated in FIG. 14 is detected, the intensity output I and the position output Xm are totaled and the substrate storage state is determined by a method different from the above-described modification. .
[0098]
First, the receiver controller 63 calculates the intensity output I and the position output Xm based on the signal received by the PSD 52 when the LD 51 moves along the height direction of the cassette 11, and calculates the intensity output I and the position output Xm. Transmit to the detection module 66. Then, as shown in FIG. 15A, the substrate detection module 66 outputs a position output Xm for each groove 11d of the cassette 11 based on the intensity output I and the position output Xm based on the signal received by the PSD 52. The distribution of the intensity output I totaled in accordance with the above is obtained. In the signal received by the PSD 52 after being reflected on the surface of the substrate W as in the example of FIG. 14, the signal output position to the PSD 52 moves in the direction opposite to the moving direction of the LD 51, and the intensity output I decreases. Will be. Therefore, as shown in FIG. 15A, the distribution of the intensity outputs I totaled in correspondence with the position outputs Xm is a distribution of the reflection area in a multivalent function. Note that FIG. 15A shows a case where the processing is performed with no data when the intensity output I is equal to or less than the intensity threshold Iv.
[0099]
Next, when a plurality of intensity outputs I exist for the same position output Xm (in the case of FIG. 15A), the substrate detection module 66 determines the intensity as shown in FIG. The distribution is corrected to a monovalent distribution leaving only the larger value of the output I.
[0100]
Then, the board detection module 66 calculates the entire reception signal width C2 corresponding to the distribution length of the intensity output I from the distribution of FIG. 15A or 15B. Further, the length D3 of the portion where the distribution of the intensity output I does not exist is calculated from the distribution of FIG. By calculating the length D3, the signal path to the PSD 52 is blocked by the substrate W, so that the signal received via only one linear path from the LD 51 in the entire width C2 is not received. This means that the reception signal cutoff width D3 corresponding to the length has been calculated.
[0101]
After calculating the overall width C2 and the cutoff width D3 as described above, the substrate detection module 66 then determines the stored state of the substrate W in the same procedure as in the present embodiment. That is, the board detection module 66 first compares a predetermined threshold value Cv (known PSD width Cv) set in advance based on the size of the signal receivable width in each PSD 52 with the entire width C2, and determines the size of the board W. Then, a predetermined threshold value Dv (known substrate width Dv) set in advance is compared with the cutoff width D3. Thereby, the storage state of the substrate W stored in each groove 11d is determined.
[0102]
As described above, according to the modification described with reference to FIG. 15, it is possible to calculate the overall width C2 and the cutoff width D3 by removing the signal reflected and received on the surface of the substrate W. Thus, even when there is a substrate W having a significantly different reflectance on the substrate surface, the tilt state of the substrate W can be accurately evaluated regardless of the influence of the difference in the reflectance. Therefore, the same operational effects as those of the present embodiment can be obtained, and even if the substrates W having different reflectances on the substrate surface are mixed in the cassette 11, the stored state of the substrates W can be accurately detected.
[0103]
Further, even if there is no positional information when the LD 51 (transmitter 51) moves, the overall width C2 and the cutoff width D3 along the height direction of the cassette 11 can be calculated. That is, since information on the position of the LD 51 is not required for calculating the overall width C2 and the cutoff width D3, a mechanism that can detect the moving position such as the stepping motor 60 with high accuracy is used as the moving mechanism of the transmitter 51. No need. For example, the moving mechanism of the transmitter 51 can be simplified by using a simple mechanism such as an air cylinder as the elevating mechanism 5c of the transmitter 51.
[0104]
(3) In the present embodiment, the receivers 52 are provided so as to correspond to the grooves 11d of the cassette 11, respectively. For example, as shown in FIG. 16, even if each receiver 52 is provided so as to correspond to each of a plurality of stages (every two stages in FIG. 16) of each groove 11d in the cassette 11, the effect of the present invention can be obtained. Can be played. In this case, the multi-layer state and the cross slot state are determined based on the cutoff width D. In this case, there may be a plurality of cutoff widths D in the PSD output distribution. However, the entire PSD width is calculated in the same manner as in the present embodiment, and the center position of the entire PSD width is calculated. Thus, the cross slot state can be determined and detected by grasping the state of the change of the entire PSD width and the center position thereof.
[0105]
(4) As shown in the modification of FIG. 16, there is a portion (dead zone) where the receivers 52 are not arranged between the adjacent receivers 52, but they are serially arranged along the height direction of the cassette 11. The plurality of receivers 52 arranged may be provided so as to be movable in the height direction of the cassette 11 at least for a distance corresponding to the length of the dead zone. That is, for example, the member 59 shown in FIG. 2 may perform a reciprocating operation vertically by a distance corresponding to the dead zone length. With such a configuration, after the transmitter 51 is once moved up and down to detect the stored state of the substrate W, the receiver 52 is moved up and down by a distance corresponding to the length of the dead zone, and The stored state of the substrate W can be detected by moving the 51 up and down. Then, by superimposing these receiver outputs based on the signals respectively received twice in the receiver 52, the same receiver output as in the case where there is no portion where the receiver 52 is not provided exists. Obtainable. Therefore, the storage state of the substrate W in each groove 11d can be accurately detected, and the plurality of receivers 52 can be efficiently arranged without waste.
[0106]
(5) Also, in the present embodiment, the plurality of receivers arranged in series along the height direction of the cassette 11 are arranged in a single row, but this is not necessarily the case. That is, the plurality of receivers 52 may be arranged in a plurality of rows along the height direction of the cassette 11. FIG. 17 shows this modification, and shows a top view of the positional relationship between the receiver row (receiver row 68a and receiver row 68b) and the transmitter 51 arranged in two rows. FIG. A part of the line light emitted from the transmitter 51 is split via the half mirror 69 and received by the receivers 52 arranged in the receiver array 68a. The remaining linear light that has passed through the half mirror 69 is refracted by the prism 70 and received by the receivers 52 arranged in the receiver row 68b. The receivers 52 are arranged in the plurality of receiver rows 68a and 68b such that the positions of the receivers 52 in the height direction of the cassette 11 are shifted from each other. For this reason, even if there is a portion (dead zone) where the receiver 52 is not provided in one of the receiver rows, the receiver 52 is provided in a position corresponding to the portion. It can be in the installed state. Thereby, once the storage state of the substrate W is detected by the transmitter 51, the receiver row arranged in a single row is moved up and down by a distance corresponding to the dead zone, and the transmitter 51 is moved up and down again. The same effect as in the case of detecting the stored state of the substrate W can be obtained. That is, by superimposing the receiver outputs received by the respective receiver columns (68a and 68b), the effect of obtaining the same receiver output as when no dead zone exists can be obtained. Therefore, the storage state of the substrate W in each groove 11d of the cassette 11 can be accurately detected, and the plurality of receivers 52 can be efficiently arranged without waste.
[0107]
In the modification shown in FIG. 17, the path of the linear light emitted as a signal from the transmitter 51 to the receiver 52 is separated using the half mirror 69 so that a plurality of receiver rows (68a, A line light can be emitted toward each receiver 52 arranged in 68b). Thereby, even when the plurality of receivers 52 arranged in series are arranged in a plurality of rows, each transmitter row (68a, 68b) arranged in a plurality of rows by one transmitter 51. ) Can be emitted simultaneously. Therefore, the device configuration of the substrate detection device 1 can be simplified. The plurality of receiver rows may be provided in three or more rows. In this case, by splitting the light twice or more by the half mirror, linear light can be emitted to the receivers in each receiver row.
[0108]
(6) In the present embodiment, an example in which the line light emitted from the transmitter 51 is directly received by the receiver 52 has been described. The reduced beam may be emitted toward the receiver 52 by reducing the irradiation diameter of the emitted linear light (beam) by the focusing means. As a condensing means, for example, a lens is arranged between the transmitter 51 and the receiver 52, whereby the irradiation diameter of the beam emitted from the transmitter 51 can be reduced. According to this configuration, it is possible to prevent the irradiated beam from being diffused, and it is possible to easily form a stable beam path from the transmitter 51 to the receiver 52. For this reason, the receiving accuracy of the beam emitted from the transmitter 51 in the receiver 52 is improved, and the stored state of the substrate W in the FOUP can be accurately detected.
[0109]
(7) The path of the linear light emitted as a signal from the transmitter 51 to the receiver 52 is changed by using the linear light reflecting means, the linear light refracting means, or the linear light guiding means, so that the receiver 52 It may be one that adjusts the angle of irradiation of linear light to the object. A mirror or the like can be used as the linear light reflecting means as shown in FIG. 17, and a prism or the like can be used as the linear light refracting means as shown in FIG. As the linear light guiding means, an optical conduit such as an optical fiber is used. For example, even if the distal end of the optical fiber is extended to the mounting position of the transmitter 51 in FIG. 1 and attached, the linear light is emitted from the distal end. Good. As described above, by using the linear light reflecting means, the linear light refracting means, or the linear light guiding means, the linear light irradiation angle to the receiver 52 can be easily adjusted, and the receiving accuracy of the linear light can be improved. Can be.
[0110]
(8) As shown in the schematic diagram of FIG. 18A, in the present embodiment, the transmitter 51 is attached to an arm 53 that can swing, so that the transmitter 51 can advance into the cassette 11. Yes, but not necessarily. For example, as shown in FIG. 18 (b), a plurality of link members are combined in a bellows shape, and the tip of a bellows arm 71 which can vertically advance and retreat with respect to the cassette 11 (can reciprocate in both arrow directions in the figure). The transmitter 51 may be attached to the transmitter. With this configuration, the same effect as the present invention can be obtained.
[0111]
(9) In the present embodiment, only the transmitter 51 is mounted so as to be able to advance and retreat into the cassette 11, but the plurality of receivers 52 are also provided so as to be able to advance and retreat into the cassette 11. You may. For example, an arm for integrally supporting the plurality of receivers 52 may be attached to the member 59 shown in FIG. 2, and this arm may be supported so as to be able to advance and retreat into the cassette 11.
[0112]
(10) In the present embodiment, the transmitter 51 is attached to the shutter 5a. However, even if the transmitter 51 is attached to an elevating device provided separately from the shutter driving device 5, The same effect as the invention can be obtained.
[0113]
(11) In the present embodiment, the plurality of receivers 52 are attached to the member 59 extending parallel to the partition 10, but the plurality of receivers 52 are attached to the partition 10 integrally. However, the same effects as those of the present invention can be obtained.
[0114]
(12) In the present embodiment, the stored state of the substrate W is detected by blocking the signal path formed between the transmitter 51 and the receiver 52 by the presence of the substrate W. However, this need not be the case. For example, the presence of the substrate W may be detected by receiving the signal reflected on the peripheral side surface of the substrate W by the receiver 52.
[0115]
【The invention's effect】
As described above, according to the first aspect of the present invention, a plurality of receivers are arranged and mounted in series on a member facing the opening of the substrate storage container. , The signal emitted from the transmitter can be received stably, and the stored state of the substrate in the FOUP can be accurately detected. Also, since only the transmitter moves up and down, the mechanism of the substrate detecting device can be simplified. By arranging a plurality of receivers in series, there is no need to create an integrated long receiver, and a board detection device that detects the board by moving only the transmitter up and down can be easily realized. it can. Therefore, it is possible to obtain a high-precision detection device capable of accurately detecting the storage state of the substrate in the FOUP with a simple device configuration.
[0116]
According to the second aspect of the present invention, the signal path formed between the transmitter that has advanced into the substrate storage container and the serially arranged receivers is blocked by the substrate, so that the substrate detection can be performed. Since this is performed, reliable and accurate substrate detection can be performed. In addition, the transmitter is attached to the shielding plate driving device, and the board is detected together with the raising and lowering operation of the shielding plate driving device, so that quick detection is possible, and a vertical moving mechanism for the transmitter is separately provided. There is no need to provide them, and the mechanism of the substrate detection device can be simplified.
[0117]
According to the third aspect of the present invention, the storage state of the substrate in each groove can be accurately detected, and a plurality of receivers can be efficiently arranged without waste.
[0118]
According to the invention of claim 4, it is easy to form a stable line light path from the transmitter to the receiver, the accuracy of receiving the line light emitted from the transmitter is improved, and the substrate in the FOUP is The storage state can be accurately detected.
[0119]
According to the fifth aspect of the invention, it is possible to easily adjust the irradiation angle of the linear light to the receiver, and it is possible to improve the receiving accuracy of the linear light.
[0120]
According to the invention of claim 6, by calculating the reception signal cutoff width and comparing it with a predetermined threshold value, it is possible to detect a state in which a plurality of substrates are stored in a stacked state, and to reduce the entire reception signal width. By calculating and comparing the calculated value with a predetermined threshold value, it is possible to detect a state in which the board is stored obliquely. Therefore, it is possible to accurately detect an irregular substrate storage state.
[0121]
According to the seventh aspect of the present invention, it is possible to calculate the entire reception signal width and the reception signal cutoff width by removing the signal reflected and received on the surface of the substrate. This makes it possible to accurately evaluate the tilt state of the substrate regardless of the influence of the difference in reflectance even when substrates having significantly different reflectances on the substrate surface coexist. Then, by comparing the reception signal cutoff width with a predetermined threshold value, it is possible to detect a state in which a plurality of substrates are stored in a stack, and by comparing the entire reception signal width with the predetermined threshold value, the substrate is stored obliquely. Status can be detected. Therefore, even if substrates having different reflectances on the substrate surface are mixed in the substrate storage container, the stored state of the substrate can be accurately detected.
[0122]
According to the eighth aspect of the present invention, it is possible to calculate the entire reception signal width and the reception signal cutoff width by removing a signal reflected and received on the surface of the substrate. This makes it possible to accurately evaluate the inclination state of the substrate regardless of the influence of the difference in the reflectance even when there is a substrate having a significantly different reflectance on the substrate surface. Then, by comparing the reception signal cutoff width with a predetermined threshold value, it is possible to detect a state in which a plurality of substrates are stored in a stack, and by comparing the entire reception signal width with the predetermined threshold value, the substrate is stored obliquely. Status can be detected. Therefore, even if substrates having different reflectances on the substrate surface are mixed in the substrate storage container, the stored state of the substrate can be accurately detected.
[0123]
According to the ninth aspect of the present invention, by calculating the reception signal cutoff width and comparing it with a predetermined threshold value, it is possible to detect a state in which a plurality of substrates are stored in a stack, and to reduce the entire reception signal width. By calculating and comparing the calculated value with a predetermined threshold value, it is possible to detect a state in which the board is stored obliquely. That is, it is possible to accurately detect an irregular substrate storage state. Then, by comparing the reception signal cutoff width with a predetermined threshold value set based on the reception signal cutoff position, the FOUP is shifted from each groove toward the opening side and is stored slightly inclined, but is stored normally. It is possible to accurately detect even a delicate storage state that may be judged to be the same.
[0124]
According to the tenth aspect of the present invention, after the transmitter is temporarily moved up and down to detect the stored state of the substrate, the receiver is equivalent to the length of the portion where the receiver is not disposed between adjacent receivers. By moving the transmitter up and down by the distance and moving the transmitter up and down again, the stored state of the substrate can be detected. Then, by superimposing these receiver outputs based on the signals received by the receiver, it is possible to obtain the same receiver output as when there is no portion where the receiver is not provided. Therefore, the storage state of the substrate in each groove can be accurately detected, and the plurality of receivers can be efficiently arranged without waste.
[0125]
According to the eleventh aspect of the present invention, the receivers arranged in a plurality of rows can be arranged such that the positions of the receivers in the height direction of the substrate storage container are shifted from each other. As a result, even if there is a portion where a receiver is not provided in one receiver row, a state where the receiver is provided in another receiver row at a position corresponding to the portion. Can be Therefore, the storage state of the substrate in each groove can be accurately detected, and the plurality of receivers can be efficiently arranged without waste. Further, it is also possible to detect the inclination due to the protrusion of the substrate.
[0126]
According to the twelfth aspect of the present invention, even when a plurality of receivers arranged in series are arranged in a plurality of rows, a single transmitter can be used to arrange each receiver row arranged in a plurality of rows. It can emit line light at the same time. Therefore, the device configuration can be simplified.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams illustrating a state in which a substrate detection apparatus according to an embodiment of the present invention is mounted on a substrate processing apparatus. FIG. 1A is a top view, and FIG. Fig. 3 shows a view from the device side.
FIG. 2 is a schematic view of a substrate processing apparatus to which the substrate detection device shown in FIG. 1 is attached.
FIG. 3 is a schematic diagram showing a control configuration of the substrate detection device shown in FIG.
FIG. 4 is a schematic view showing a state in which a plurality of receivers are arranged in series along the height direction of the substrate storage container in the substrate detection device shown in FIG.
5 is a schematic diagram illustrating a configuration of a PSD element which is a receiver of the substrate detection device shown in FIG.
FIG. 6 is a diagram showing a distribution of a receiver output detected when the substrate is stored in a groove of the substrate storage container in a normal state in the substrate detection device shown in FIG. 1;
7 is a diagram illustrating a distribution of a receiver output detected when a plurality of substrates are stored in the groove of the substrate storage container in a state where a plurality of substrates are stacked in the substrate detection device illustrated in FIG. 1;
FIG. 8 is a diagram showing a distribution of a receiver output detected when the substrate is stored in the groove of the substrate storage container in an obliquely inserted state in the substrate detection device shown in FIG. 1;
FIG. 9 is a diagram illustrating a state in which the substrate is shifted from the groove of the substrate storage container toward the opening side and slightly tilted (projection state).
10 shows the distribution of the output of the receiver detected when the substrate is stored in the groove of the substrate storage container in a normal state (FIG. 10A), and the pop-out state in the substrate detection device shown in FIG. 11 (a) and 11 (b) are diagrams respectively showing the distribution of the output of the receiver detected in the case where it is stored in FIG.
11 is a diagram illustrating a processing flow for detecting a stored state of a substrate by the substrate detection device illustrated in FIG.
FIG. 12 is a diagram illustrating a signal path when a substrate is stored in a tilted state.
FIG. 13 is a diagram illustrating a substrate detection device according to a modification, and is a diagram illustrating a distribution of the intensity output and the position output of the receiver detected when the substrate is stored in an inclined state.
FIG. 14 is a diagram illustrating a stored state of a substrate corresponding to the detection example of FIG. 13;
FIG. 15 is a diagram illustrating a substrate detection device according to a modification, and is a diagram illustrating a distribution of the intensity output of the receiver with respect to the position output detected when the substrate is stored in an inclined state.
FIG. 16 is a diagram illustrating a substrate detection device according to a modification.
FIG. 17 is a diagram illustrating a substrate detection device according to a modification.
FIG. 18 is a diagram illustrating a substrate detection device according to a modification.
FIG. 19 is a diagram illustrating a state in which a substrate is stored in the FOUP.
FIG. 20 is a perspective view showing a state in which a substrate is stored in the FOUP.
[Explanation of symbols]
1 Substrate detection device
5 Shield plate drive
5a Shield plate
11 FOUP
11a container
11c opening
11d groove
51 transmitter
52 receiver
53 arm
59 members
66 Substrate detection module
W substrate

Claims (12)

A substrate storage container provided with an opening for inserting and removing a substrate and having a plurality of grooves for storing and holding a plurality of inserted substrates substantially horizontally is provided for detecting a stored substrate. A substrate detection device for performing,
A plurality of receivers attached to a member facing the opening and arranged in series along a height direction of the substrate storage container; and a plurality of receivers installed movably in a vertical direction of the substrate storage container. A transmitter that emits a signal toward the substrate housed in each groove of
A substrate detection device, wherein the presence / absence and state of a substrate stored in each groove of the substrate storage container are detected by receiving a signal emitted from the transmitter by the receiver. The transmitter is attached to the shielding plate driving device that moves the shielding plate that opens and closes the opening and retracts and moves up and down toward the inside of the substrate storage container. The substrate detection device according to claim 1, wherein the presence or absence and the state of the substrate are detected by blocking a path by the substrate. The plurality of receivers are provided such that each receiver corresponds to each groove of the substrate storage container, or that each receiver corresponds to each of a plurality of stages of each groove in the substrate storage container. 3. The substrate detecting device according to claim 1, wherein The reduced diameter light is emitted toward the receiver by reducing the irradiation diameter of the light emitted as a signal from the transmitter by a focusing unit. The substrate detection device according to any one of claims 1 to 7. By changing the route of the linear light emitted as a signal from the transmitter to the receiver using linear light reflecting means, linear light refracting means, or linear light guiding means, the receiver can be irradiated with linear light The substrate detection device according to any one of claims 1 to 4, wherein the angle is adjusted. Based on a receiver output based on a signal received by the receiver, for each groove of the substrate storage container, totaling is made in correspondence with the position of the transmitter moving along the substrate storage container height direction. And the length of the portion where the signal was not received in the entire width of the received signal, because the signal path leading to the receiver was blocked by the substrate. And the received signal cutoff width corresponding to
A predetermined threshold set based on the size of the signal receivable width in each of the receivers and the received signal overall width are compared, and a predetermined threshold and the received signal cutoff width set based on the size of the substrate are provided. The substrate detection device according to any one of claims 1 to 5, wherein the storage state of the substrate stored in each of the grooves is determined by comparing. The receiver is capable of detecting a strength of a received signal and a reception position of the received signal in the receiver,
The receiver outputs an intensity output corresponding to the intensity of the signal received by the receiver and a position output corresponding to the reception position, or can calculate the intensity output and the position output. Output status information,
Based on the intensity output and the position output by the signal received by the receiver, for each groove of the substrate storage container, the position of the transmitter moving along the substrate storage container height direction And the total width of the received signal corresponding to the distribution length of the intensity output corresponding to the total length of the received signal. Calculate the received signal cutoff width corresponding to the length of the portion where the signal received only through the straight line path was not received,
A predetermined threshold set based on the size of the signal receivable width in each of the receivers and the received signal overall width are compared, and a predetermined threshold and the received signal cutoff width set based on the size of the substrate are provided. The substrate detection device according to any one of claims 1 to 5, wherein the storage state of the substrate stored in each of the grooves is determined by comparing. The receiver is capable of detecting a strength of a received signal and a reception position of the received signal in the receiver,
The receiver outputs an intensity output corresponding to the intensity of the signal received by the receiver and a position output corresponding to the reception position, or can calculate the intensity output and the position output. Output status information,
Based on the intensity output and the position output by the signal received by the receiver when the transmitter moves along the substrate storage container height direction, for each groove of the substrate storage container, The entire width of the received signal corresponding to the distribution length of the intensity output corresponding to the position output, and the transmitter in the entire width of the received signal by blocking a signal path to the receiver by the substrate. And a received signal cutoff width corresponding to the length of the portion where the signal received via only one straight path from the signal was not received, and
A predetermined threshold set based on the size of the signal receivable width in each of the receivers and the received signal overall width are compared, and a predetermined threshold and the received signal cutoff width set based on the size of the substrate are provided. The substrate detection device according to any one of claims 1 to 5, wherein the storage state of the substrate stored in each of the grooves is determined by comparing. Based on a receiver output based on a signal received by the receiver, for each groove of the substrate storage container, totaling is made in correspondence with the position of the transmitter moving along the substrate storage container height direction. And the length of the portion where the signal was not received in the entire width of the received signal, because the signal path leading to the receiver was blocked by the substrate. Calculate the received signal cutoff width corresponding to the position, and the received signal cutoff position corresponding to the position where the center of the receiver signal cutoff width exists in the entire received signal width,
A predetermined threshold set based on the size of the substrate and the cutoff position is compared with the reception signal cutoff width, and a predetermined threshold set based on the size of the signal receivable width in each of the receivers and the reception are set. The substrate detection device according to any one of claims 1 to 5, wherein a storage state of the substrate stored in each of the grooves is determined by comparing a signal cutoff width. The plurality of receivers arranged in series along the substrate storage container height direction is at least a distance equivalent to the length of a portion where the receiver between the adjacent receivers is not provided, The substrate detection device according to any one of claims 1 to 9, wherein the substrate detection device is provided so as to be movable in a height direction of the substrate storage container. The plurality of receivers arranged in series along the substrate storage container height direction are arranged in a plurality of rows along the substrate storage container height direction. The substrate detection device according to claim 1. By splitting the path of the linear light emitted as a signal from the transmitter to the receiver using a half mirror, the linear light is emitted toward the receivers arranged in the plurality of rows. The substrate detecting device according to claim 11, wherein

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