JP3594819B2 - Substrate processing equipment - Google Patents

Description

【００３０】
この処理順序によれば、未処理基板はインデクサＩＤから払い出されて、密着強化処理、冷却処理およびレジスト塗布処理が行われた後、加熱処理部ＨＰ１にてプリベークが施される（処理順序▲５▼）。その後、冷却処理の後インターフェイスＩＦを介して露光装置に渡され、露光処理に供される（処理順序▲７▼）。そして、露光済みの基板はインターフェイスＩＦを介してユニット配置部ＭＰに戻され、エッジ露光処理部ＥＥ１にて端縁部露光が行われた後（処理順序▲８▼）、露光後ベークプレート部ＰＥＢにて露光後ベークが施され（処理順序▲９▼）、さらにその後、冷却処理、現像処理が行われ、処理済み基板として再びインデクサＩＤに戻される。すなわち、本実施形態においては、加熱処理部ＨＰ１が露光前ベーク部に、露光後ベークプレート部ＰＥＢが露光後ベーク部にそれぞれ相当する。
【００３１】
なお、表１中において、かっこ書きにて示した処理部は、並行処理が行われる処理部を示している。すなわち、各処理工程での所要時間は同一ではないため、所要時間の長い工程については等価な２つの処理部を割り当てて、そのいずれかにおいて処理するようにしているのである。例えば、インデクサＩＤから払い出された未処理基板は、密着強化部ＡＨＬ１または密着強化部ＡＨＬ２のいずれか空いている方に搬入され、またレジスト塗布処理が終了した基板は加熱処理部ＨＰ１または加熱処理部ＨＰ２のいずれかに搬入されプリベークが行われるのである。従って、加熱処理部ＨＰ２も露光前ベーク部に相当する。但し、本明細書においては、理解を容易にするため、表１中のかっこ書きにて示した処理部以外の処理部に順次搬送されて、一連の基板処理が行われるものとする。
【００３２】
＜２．プリベークおよび露光後ベークにおける基板の向き＞
表１に示す処理順序において、基板がインデクサＩＤから払い出された後、インターフェイスＩＦに渡されるまでの工程（処理順序▲１▼〜▲７▼）では、各処理部における基板の向きは同一である。すなわち、各処理部に所定の向きにて搬入された基板は、それと同一の向きにて搬出され、そのままの向きで次工程の処理部に搬入されるという手順が繰り返されるのである。なお、塗布処理部ＳＣ１は、基板を回転させつつレジスト塗布を行うのであるが、回転前の基板の向きと同じ向きで回転を停止するようにしているため、処理前後の基板の向きは同一となる。
【００３３】
ところで、通常、基板にはその結晶方位を示すオリフラまたはノッチが設けられており、基板の向きはそのようなオリフラまたはノッチを光学的に検出することによって認識される。本実施形態においても、基板がインデクサＩＤから払い出された後、インターフェイスＩＦに渡されるまでの工程におけるその基板の向きを検知すべく、密着強化部ＡＨＬ１から冷却処理部ＣＰ２までのいずれかの処理部に基板のオリフラまたはノッチを光学的に検出してその向きを検知する機構を設けておく。なお、密着強化部ＡＨＬ１から冷却処理部ＣＰ２までのいずれかの処理部に光学的検出機構を設ける代わりに、基板処理装置内に光学的検出専用の処理部を設けるようにしてもよい。そして、検知された露光処理前における基板の向きは制御部１０に伝達され、記憶される。
【００３４】
次に、基板は露光処理を行う露光装置に渡されるのであるが、露光装置は、露光処理前における基板の向きとは関係なく、露光処理に最適な向きに基板を回動させて処理を行い、その向きのまま露光処理後の工程に渡す。従って、エッジ露光処理部ＥＥ１に搬入される基板の向きは露光処理前工程での基板の向きとは異なるものとなっている可能性が高い。
【００３５】
ここで、本実施形態においては、制御部１０が露光処理前における基板の向きを参照しつつエッジ露光処理部ＥＥ１に指示を与え、エッジ露光処理部ＥＥ１がその指示に基づいて基板を回動させ、当該基板の向きを露光処理前工程での基板の向きと同一または１８０゜回動させた向きにして搬出するのである。よって、本実施形態においては、エッジ露光処理部ＥＥ１（ＥＥ２）が基板回動手段に相当し、制御部１０が回動制御手段に相当する。
【００３６】
図６は、エッジ露光処理部ＥＥ１の概略を模式的に示した平面図である。そもそも、エッジ露光処理部ＥＥ１は、基板Ｗの端縁部のレジスト膜を除去するために、露光部５０から基板端縁部に光を照射しつつ、駆動部５１がその基板を回転させることによって、基板Ｗの端縁部全体を露光する処理部である。そして、一般に、エッジ露光処理部ＥＥ１は、エッジセンサ５２にオリフラ５５（またはノッチ）を光学的に検出させることによって基板の回転角度を認識しつつ端縁部露光を行う。つまり、エッジ露光処理部ＥＥ１は、端縁部露光を行うために、基板を回転させる駆動部５１と基板の回転角度を検出する機構であるエッジセンサ５２とを備えているのである。そして、本実施形態では、エッジ露光処理部ＥＥ１がそのような本来備えている機能を用い、制御部１０の指示に従って基板の向きを調整するのである。
【００３７】
端縁部露光が終了し、向きの調整が行われた基板は、調整後そのままの向きにて露光後ベークプレート部ＰＥＢに渡される。なお、露光後ベークプレート部ＰＥＢからインデクサＩＤに渡されるまでの工程においては、上記露光前処理工程と同様に、各処理部における基板の向きは同一である。
【００３８】
以上のように、本実施形態においては、制御部１０がエッジ露光処理部ＥＥ１を制御し、露光前ベーク部たる加熱処理部ＨＰ１における基板の向きと露光後ベーク部たる露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が０゜または１８０゜となるようにエッジ露光処理部ＥＥ１に基板の向きを調整させているのである。
【００３９】
図７は、露光後ベークプレート部ＰＥＢの概略を模式的に示した平面図である。同図により、上記のことをさらに敷衍すると、露光前ベーク部たる加熱処理部ＨＰ１における基板Ｗの搬入口側端部ＷＥが露光後ベーク部たる露光後ベークプレート部ＰＥＢにおいて搬入口側ＩＰまたは奥側ＯＰに位置するように、制御部１０がエッジ露光処理部ＥＥ１に基板Ｗを回動させているのである（図７の場合、加熱処理部ＨＰ１における搬入口側端部ＷＥを露光後ベークプレート部ＰＥＢにおいて奥側ＯＰに位置させている）。なお、露光後ベークプレート部ＰＥＢにおける搬入口側ＩＰとは、搬送ロボットＴＲ１がアクセスするために露光後ベークプレート部ＰＥＢに設けられた搬入口６０に最も近い側であり、奥側ＯＰとは搬入口６０から最も遠い側である。加熱処理部ＨＰ１における搬入口側および奥側も同様の定義である。また、加熱処理部ＨＰ１における基板Ｗの搬入口側端部ＷＥとは、加熱処理部ＨＰ１の搬入口に最も近い搬入口側に位置していた基板Ｗの端部である。
【００４０】
ところで、上記相対角度を０゜とするか１８０゜とするかは、レジストの種類およびレジストの目標膜厚によって決定される。
【００４１】
周知のように、レジストには、露光された部分が現像液によって溶解されるポジティブレジストと露光された部分が現像後に残留するネガティブレジストとの２種類がある。また、半導体チップ等の最終製品に要求される特性に応じて、塗布処理部ＳＣ１、ＳＣ２において基板に塗布するレジストの目標膜厚が異なる。そして、レジストの種類およびレジストの目標膜厚は、予め制御部１０に入力されており、制御部１０はそれらの情報を参照することにより、レジストの種類およびレジストの目標膜厚に応じて上記相対角度を０゜とするか１８０゜とするかを決定し、エッジ露光処理部ＥＥ１に基板の向きを調整させるのである。レジストの種類およびレジストの目標膜厚に基づく相対角度の決定は、具体的には以下のようにして行われる。
【００４２】
＜２−１．第１のパターン＞
図３は、レジストの膜厚と現像後のレジスト線幅との相関を示す図である。同図に示すように、レジストの膜厚と現像後のレジスト線幅との相関関係は、膜厚ＴＨ付近の膜厚に着眼した場合膜厚ＴＨを境界にして２つのパターンに分類することができる。すなわち、基板に塗布されたレジストの膜厚が膜厚ＴＨよりも厚いときは、レジスト膜厚が厚くなるほどレジスト線幅が太くなるという正の特性が認められ、膜厚ＴＨよりも薄いときは、レジスト膜厚が厚くなるほどレジスト線幅が細くなるという負の特性が認められる。なお、このようなレジストの膜厚とレジスト線幅との相関関係は、レジストの種類によらず同じである。
【００４３】
ここでは、まず、第１のパターンとして、レジストの目標膜厚が膜厚ＴＨよりも厚いＡであって、かつレジストの種類がネガティブレジストである場合について説明する。
【００４４】
既述したように、加熱処理部ＨＰ１および露光後ベークプレート部ＰＥＢでは、搬送ロボットＴＲ１がアクセスする搬入口側の方が奥側よりも外気に曝されやすく、プリベークおよび露光後ベークにおいて搬入口側の基板の温度の方が奥側の温度よりも若干低くなるという温度勾配が生じる。つまり、加熱処理部ＨＰ１および露光後ベークプレート部ＰＥＢのいずれにおいても搬入口側から奥側に向けて温度が高くなるという同様の温度勾配が生じているのである。
【００４５】
プリベークは、塗布処理部ＳＣ１において塗布されたレジスト中の余分な溶媒成分を蒸発させ、レジストと基板との密着性を強固にするために行われるものであるが、基板に温度勾配が生じると溶媒成分の蒸発の程度に差が生じ、温度の高い奥側の方が搬入口側よりも溶媒成分の蒸発の程度が大きくなる。その結果、溶媒成分の蒸発が少ない搬入口側のレジスト膜厚の方が奥側のレジスト膜厚よりも厚くなるのである。
【００４６】
レジストの目標膜厚が膜厚Ａである場合、図３に示すように、膜厚Ａの近傍においてはレジスト膜厚が厚くなるほどレジスト線幅が太くなるため、レジスト膜厚の厚い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも太くなる。つまり、レジストの目標膜厚が膜厚Ａである場合、加熱処理部ＨＰ１でのプリベークにおけるレジスト線幅への温度依存性は、温度が高くなるにしたがってレジスト線幅が細くなるという特性であり、温度の低い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも太くなるのである。
【００４７】
一方、露光後ベークプレート部ＰＥＢでの露光後ベークにおいては、基板に温度勾配が生じると露光時の光化学反応による生成物である酸の活性度に差が生じる。すなわち、温度が高いほど酸活性が大きくなるため、温度の高い奥側の方が搬入口側よりも酸活性が大きくなる。
【００４８】
レジストの種類がネガティブレジストである場合、酸活性が大きくなると露光部分のレジストの硬化の程度が大きくなり、その結果レジスト線幅が太くなるのである。従って、酸活性の大きい奥側のレジスト線幅の方が搬入口側のレジスト線幅よりも太くなる。つまり、レジストの種類がネガティブレジストである場合、露光後ベークプレート部ＰＥＢでの露光後ベークにおけるレジスト線幅への温度依存性は、温度が高くなるにしたがってレジスト線幅が太くなるという特性であり、温度の低い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも細くなるのである。
【００４９】
上述の如く、加熱処理部ＨＰ１および露光後ベークプレート部ＰＥＢのいずれにおいても搬入口側から奥側に向けて温度が高くなるという同様の温度勾配が生じている。そして、第１のパターンでは、プリベークにおけるレジスト線幅への温度依存性と露光後ベークにおけるレジスト線幅への温度依存性とが逆特性となるため、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける基板の向きとを同じにすれば、プリベークにおいて基板に生じた温度勾配が線幅に与える影響と露光後ベークにおいて当該基板に生じた温度勾配が線幅に与える影響とが相殺され、最終的なレジスト線幅均一性は向上する。
【００５０】
従って、第１のパターンにおいては、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が０゜となるように基板の向きを調整すれば、現像処理後のレジスト線幅均一性を向上させることができる。逆に、当該相対角度が１８０゜となるように基板の向きを調整すると、プリベークにおいて基板に生じた温度勾配が線幅に与える影響と露光後ベークにおいて当該基板に生じた温度勾配が線幅に与える影響とが加算され、現像処理後のレジスト線幅均一性が著しく劣化する。
【００５１】
＜２−２．第２のパターン＞
次に、第２のパターンとして、レジストの目標膜厚が膜厚ＴＨよりも厚いＡであって、かつレジストの種類がポジティブレジストである場合について説明する。
【００５２】
上記第１のパターンと同様に、レジストの目標膜厚が膜厚Ａであるため、加熱処理部ＨＰ１でのプリベークにおけるレジスト線幅への温度依存性は、温度が高くなるにしたがってレジスト線幅が細くなるという特性であり、温度の低い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも太くなる。
【００５３】
一方、露光後ベークプレート部ＰＥＢでの露光後ベークにおいては、基板に温度勾配が生じると露光時の光化学反応による生成物である酸の活性度に差が生じ、温度が高いほど酸活性が大きくなるため、温度の高い奥側の方が搬入口側よりも酸活性が大きくなるのは上記第１のパターンと同様である。
【００５４】
第２のパターンでは、レジストの種類がポジティブレジストであるため、酸活性が大きくなると露光部分が現像液によって溶かされる程度が大きくなり、その結果レジスト線幅が細くなるのである。従って、酸活性の大きい奥側のレジスト線幅の方が搬入口側のレジスト線幅よりも細くなる。つまり、レジストの種類がポジティブレジストである場合、露光後ベークプレート部ＰＥＢでの露光後ベークにおけるレジスト線幅への温度依存性は、温度が高くなるにしたがってレジスト線幅が細くなるという特性であり、温度の低い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも太くなるのである。
【００５５】
加熱処理部ＨＰ１および露光後ベークプレート部ＰＥＢのいずれにおいても搬入口側から奥側に向けて温度が高くなるという同様の温度勾配が生じている。そして、第２のパターンでは、プリベークにおけるレジスト線幅への温度依存性と露光後ベークにおけるレジスト線幅への温度依存性とが同じ特性となるため、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける基板の向きとを反転させれば、プリベークにおいて基板に生じた温度勾配が線幅に与える影響と露光後ベークにおいて当該基板に生じた温度勾配が線幅に与える影響とが相殺され、最終的なレジスト線幅均一性は向上する。
【００５６】
従って、第２のパターンにおいては、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が１８０゜となるように基板の向きを調整すれば、現像処理後のレジスト線幅均一性を向上させることができる。逆に、当該相対角度が０゜となるように基板の向きを調整すると、プリベークにおいて基板に生じた温度勾配が線幅に与える影響と露光後ベークにおいて当該基板に生じた温度勾配が線幅に与える影響とが加算され、現像処理後のレジスト線幅均一性が著しく劣化する。
【００５７】
＜２−３．第３のパターン＞
次に、第３のパターンとして、レジストの目標膜厚が膜厚ＴＨよりも薄いＢであって、かつレジストの種類がネガティブレジストである場合について説明する。
【００５８】
基板に温度勾配が生じると溶媒成分の蒸発の程度に差が生じ、温度の高い奥側の方が搬入口側よりも溶媒成分の蒸発の程度が大きくなり、溶媒成分の蒸発が少ない搬入口側のレジスト膜厚の方が奥側のレジスト膜厚よりも厚くなるのは、上記第１のパターンと同じである。
【００５９】
レジストの目標膜厚が膜厚Ｂである場合、図３に示すように、膜厚Ｂの近傍においてはレジスト膜厚が厚くなるほどレジスト線幅が細くなるため、レジスト膜厚の厚い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも細くなる。つまり、レジストの目標膜厚が膜厚Ｂである場合、加熱処理部ＨＰ１でのプリベークにおけるレジスト線幅への温度依存性は、温度が高くなるにしたがってレジスト線幅が太くなるという特性であり、温度の低い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも細くなるのである。
【００６０】
一方、露光後ベークプレート部ＰＥＢでの露光後ベークにおいては、上記第１のパターンと同様に、レジストの種類がネガティブレジストであるため、レジスト線幅への温度依存性は、温度が高くなるにしたがってレジスト線幅が太くなるという特性であり、温度の低い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも細くなるのである。
【００６１】
よって、第３のパターンでは、プリベークにおけるレジスト線幅への温度依存性と露光後ベークにおけるレジスト線幅への温度依存性とが同じ特性となるため、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける基板の向きとを反転させれば、プリベークにおいて基板に生じた温度勾配が線幅に与える影響と露光後ベークにおいて当該基板に生じた温度勾配が線幅に与える影響とが相殺され、最終的なレジスト線幅均一性は向上する。
【００６２】
従って、第３のパターンにおいては、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が１８０゜となるように基板の向きを調整すれば、現像処理後のレジスト線幅均一性を向上させることができる。逆に、当該相対角度が０゜となるように基板の向きを調整すると、プリベークにおいて基板に生じた温度勾配が線幅に与える影響と露光後ベークにおいて当該基板に生じた温度勾配が線幅に与える影響とが加算され、現像処理後のレジスト線幅均一性が著しく劣化する。
【００６３】
＜２−４．第４のパターン＞
次に、第４のパターンとして、レジストの目標膜厚が膜厚ＴＨよりも薄いＢであって、かつレジストの種類がポジティブレジストである場合について説明する。
【００６４】
上記第３のパターンと同様に、レジストの目標膜厚が膜厚Ｂであるため、加熱処理部ＨＰ１でのプリベークにおけるレジスト線幅への温度依存性は、温度が高くなるにしたがってレジスト線幅が太くなるという特性であり、温度の低い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも細くなるのである。
【００６５】
一方、露光後ベークプレート部ＰＥＢでの露光後ベークにおいては、上記第２のパターンと同様に、レジストの種類がポジティブレジストであるため、レジスト線幅への温度依存性は、温度が高くなるにしたがってレジスト線幅が細くなるという特性であり、温度の低い搬入口側のレジスト線幅の方が奥側のレジスト線幅よりも太くなるのである。
【００６６】
よって、第４のパターンでは、プリベークにおけるレジスト線幅への温度依存性と露光後ベークにおけるレジスト線幅への温度依存性とが逆特性となるため、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける基板の向きとを同じにすれば、プリベークにおいて基板に生じた温度勾配が線幅に与える影響と露光後ベークにおいて当該基板に生じた温度勾配が線幅に与える影響とが相殺され、最終的なレジスト線幅均一性は向上する。
【００６７】
従って、第４のパターンにおいては、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が０゜となるように基板の向きを調整すれば、現像処理後のレジスト線幅均一性を向上させることができる。逆に、当該相対角度が１８０゜となるように基板の向きを調整すると、プリベークにおいて基板に生じた温度勾配が線幅に与える影響と露光後ベークにおいて当該基板に生じた温度勾配が線幅に与える影響とが加算され、現像処理後のレジスト線幅均一性が著しく劣化する。
【００６８】
＜２−５．総括＞
以上のように、レジストの目標膜厚は、加熱処理部ＨＰ１でのプリベークにおけるレジスト線幅への温度依存性に影響を与える。以下の表２はその内容をまとめたものである。
【００６９】
【表２】

【００７０】
加熱処理部ＨＰ１でのプリベークにおいて基板に温度勾配が生じた結果、搬入口側のレジスト線幅と奥側のレジスト線幅との間に線幅差ｔが発生する。
【００７１】
一方、レジストの種類は、露光後ベークプレート部ＰＥＢでの露光後ベークにおけるレジスト線幅への温度依存性に影響を与える。以下の表３はその内容をまとめたものである。
【００７２】
【表３】

【００７３】
露光後ベークプレート部ＰＥＢでの露光後ベークにおいて基板に温度勾配が生じた結果、搬入口側のレジスト線幅と奥側のレジスト線幅との間に線幅差Ｔが発生する。なお、露光後ベークでの温度依存性の方がプリベークでの温度依存性よりも大きいためＴ＞ｔとなる。
【００７４】
このように、レジストの目標膜厚が膜厚ＴＨよりも厚いか薄いか、及び、レジストの種類がポジティブレジストかネガティブレジストかによって条件の組み合わせは４パターン存在し、それぞれのパターンについて、プリベークにて基板に生じた温度勾配が線幅に与える影響と露光後ベークにて当該基板に生じた温度勾配が線幅に与える影響とを相殺するようにしているのである。
【００７５】
図４は、レジストの種類がネガティブレジストである場合の線幅均一性を示す図である。同図の横軸には、露光後ベークプレート部ＰＥＢ内における基板の位置を示している。
【００７６】
レジストの種類がネガティブレジストである場合において、レジストの目標膜厚が膜厚ＴＨよりも厚いＡのときは（第１のパターン）、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が０゜となるように基板の向きを調整すれば、温度勾配が線幅に与える影響が相殺され、線幅差はＴ−ｔとなる（図４中の実線）。逆に、当該相対角度が１８０゜となるように基板の向きを調整すると、温度勾配が線幅に与える影響が加算され、線幅差はＴ＋ｔとなる（図４中の点線）。
【００７７】
また、レジストの種類がネガティブレジストである場合において、レジストの目標膜厚が膜厚ＴＨよりも薄いＢのときは（第３のパターン）、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が１８０゜となるように基板の向きを調整すれば、温度勾配が線幅に与える影響が相殺され、線幅差はＴ−ｔとなる（図４中の実線）。逆に、当該相対角度が０゜となるように基板の向きを調整すると、温度勾配が線幅に与える影響が加算され、線幅差はＴ＋ｔとなる（図４中の点線）。
【００７８】
図５は、レジストの種類がポジティブレジストである場合の線幅均一性を示す図である。図４と同様に、図５の横軸には、露光後ベークプレート部ＰＥＢ内における基板の位置を示している。
【００７９】
レジストの種類がポジティブレジストである場合において、レジストの目標膜厚が膜厚ＴＨよりも厚いＡのときは（第２のパターン）、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が１８０゜となるように基板の向きを調整すれば、温度勾配が線幅に与える影響が相殺され、線幅差はＴ−ｔとなる（図５中の実線）。逆に、当該相対角度が０゜となるように基板の向きを調整すると、温度勾配が線幅に与える影響が加算され、線幅差はＴ＋ｔとなる（図５中の点線）。
【００８０】
また、レジストの種類がポジティブレジストである場合において、レジストの目標膜厚が膜厚ＴＨよりも薄いＢのときは（第４のパターン）、加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が０゜となるように基板の向きを調整すれば、温度勾配が線幅に与える影響が相殺され、線幅差はＴ−ｔとなる（図５中の実線）。逆に、当該相対角度が１８０゜となるように基板の向きを調整すると、温度勾配が線幅に与える影響が加算され、線幅差はＴ＋ｔとなる（図５中の点線）。
【００８１】
＜３．変形例＞
以上、本発明の実施の形態について説明したが、この発明は上記の例に限定されるものではない。例えば、上記実施形態においては、エッジ露光処理部ＥＥ１に基板の向きを調整させるようにしていたが、これに限定されるものではなく、基板を回転させる駆動部と基板の回転角度を検出する機構とを備えた角度調整専用の基板回動処理部を設けるようにしてもよい。また、露光済みの基板をインターフェイスＩＦから搬送ロボットＴＲ１に渡すときに、インターフェイスＩＦに設けられた受け渡しロボットのＹ方向の位置を変えることによって搬送ロボットＴＲ１への基板受け渡し角度を変化させ、基板の向きを調整するようにしてもよい。換言すれば、露光を行った後、露光後ベークプレート部ＰＥＢまでの基板処理順路のうちのいずれかに設けられて加熱処理部ＨＰ１における基板の向きと露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が０゜または１８０゜となるようにできるようなものであれば、いかなる手段であってもよい。
【００８２】
また、上記の実施の形態においては、レジストの種類及びレジストの目標膜厚に応じて、露光前ベーク部たる加熱処理部ＨＰ１における基板の向きと露光後ベーク部たる露光後ベークプレート部ＰＥＢにおける当該基板の向きとのなす相対角度が０゜または１８０゜となるように基板の向きを調整して露光前加熱処理において基板に生じた温度勾配が線幅に与える影響と露光後加熱処理において当該基板に生じた温度勾配が線幅に与える影響とを相殺するようにした例を示したが、本発明はこれに限定されるものではなく、必要に応じて、露光前加熱処理において生じた温度勾配が線幅に与える影響と露光後加熱処理において基板に生じた温度勾配が線幅に与える影響とを相殺可能な所望の任意の相対角度（即ち、相対角度が０゜または１８０゜からそれぞれ所定角度ずれた場合を含む）となるように、露光前ベーク部たる加熱処理部ＨＰ１における基板の向きと露光後ベーク部たる露光後ベークプレート部ＰＥＢにおける基板の向きとを調整するようにしてもよい。
【００８３】
【発明の効果】
以上説明したように、請求項１ないし請求項６のいずれかの発明によれば、露光前加熱処理において基板に生じた温度勾配が線幅に与える影響と露光後加熱処理において当該基板に生じた温度勾配が線幅に与える影響とが相殺されるように、露光前ベーク部における基板の向きと露光後ベーク部における当該基板の向きとのなす相対角度を基板回動手段に調整させているため、現像処理後の基板におけるレジスト膜の線幅均一性を向上することができる。
【００８４】
また、請求項７の発明によれば、基板に塗布するレジストの種類およびレジスト膜厚に応じて、露光前ベーク部における基板の搬入口側端部が露光後ベーク部において搬入口側または奥側に位置するように、当該基板を回動させているため、露光前加熱処理において基板に生じた温度勾配が線幅に与える影響と露光後加熱処理において当該基板に生じた温度勾配が線幅に与える影響とが相殺され、請求項１の発明と同様の効果を得ることができる。
【図面の簡単な説明】
【図１】本発明に係る基板処理装置の全体構成を示す図である。
【図２】図１の基板処理装置における処理部の配置構成を説明する図である。
【図３】レジストの膜厚と現像後のレジスト線幅との相関を示す図である。
【図４】レジストの種類がネガティブレジストである場合の線幅均一性を示す図である。
【図５】レジストの種類がポジティブレジストである場合の線幅均一性を示す図である。
【図６】エッジ露光処理部の概略を模式的に示した平面図である。
【図７】露光後ベークプレート部の概略を模式的に示した平面図である。
【符号の説明】
１０ 制御部
ＥＥ１、ＥＥ２ エッジ露光処理部
ＨＰ１、ＨＰ２ 加熱処理部
ＰＥＢ 露光後ベークプレート部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pre-exposure bake treatment after applying a resist to a surface of a semiconductor substrate, a glass substrate for a liquid crystal display device, a glass substrate for a photomask, a substrate for an optical disk, etc. (hereinafter, simply referred to as a “substrate”). The present invention relates to a substrate processing apparatus that performs a heat treatment.
[0002]
[Prior art]
In general, a series of substrate processing is achieved by sequentially performing a resist coating process, an exposure process, a developing process, and a heat treatment associated therewith on the substrate as described above. That is, for a substrate having a surface coated with a photoresist (in the present specification, a chemically amplified resist, hereinafter simply referred to as a “resist”), a pre-exposure bake (hereinafter, referred to as “resist”) is performed before the exposure. Pre-baking ”). Then, after the substrate is subjected to an exposure process, a post-exposure baking process (hereinafter, referred to as “post-exposure bake”) is performed, and then a development process using a developing solution is performed. It is done.
[0003]
Of the above, the pre-bake is performed to evaporate an excess solvent component in the applied resist and to strengthen the adhesion between the resist and the substrate. The post-exposure bake is performed for the purpose of activating a chemical reaction that causes a change in the dissolution rate with respect to a developer due to a catalytic action of a product generated by a photochemical reaction at the time of exposure. Each of these processes performs a heat treatment on a substrate at a predetermined temperature for a predetermined time, and is performed by a heat processing unit having a hot plate.
[0004]
[Problems to be solved by the invention]
By the way, a substrate is carried in from the substrate transfer robot to the above-described heat treatment unit for performing pre-bake or post-exposure bake, and the substrate is taken out by the transfer robot. Then, the transfer robot causes the transfer arm to access from the carry-in side of the heat treatment unit. Therefore, in the heat treatment section, the carry-in side is more likely to be exposed to outside air than the back side (the side opposite to the carry-in side), and the temperature on the carry-in side tends to be slightly lower than the temperature on the back side. . Therefore, even in the pre-bake and the post-exposure bake, a temperature gradient occurs in which the temperature of the substrate on the carry-in side is slightly lower than the temperature on the back side.
[0005]
On the other hand, the orientation of the substrate subjected to a series of substrate processing is the same in each of the process before the exposure process and the process after the exposure process, but the process before the exposure process and the process after the exposure process are the same. The orientation is different from the process. This is because the exposure apparatus (stepper) that performs the exposure process performs the process by rotating the substrate in an optimal direction for the exposure process regardless of the orientation of the substrate before the exposure process, and performs the process after the exposure process in that direction. This is because it is passed to the process.
[0006]
Therefore, conventionally, no adjustment has been made between the orientation of the substrate in the pre-bake and the orientation of the substrate in the post-exposure bake, and as a result, the temperature gradient of the substrate in the pre-bake and the temperature gradient of the substrate in the post-exposure bake have been reduced. Had various correlations. Then, due to such circumstances, the line width uniformity of the resist film on the substrate after the development processing has been impaired, and there has been a problem that the yield of the product has decreased.
[0007]
The present invention has been made in view of the above problems, and has as its object to provide a substrate processing apparatus capable of improving the line width uniformity of a resist film on a substrate after a development process.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of claim 1 includes a pre-exposure bake section for performing a pre-exposure bake section on a substrate before resist application and before exposure, and a post-exposure bake section for performing a post-exposure bake processing on the substrate before post-exposure development. A substrate processing apparatus comprising: (a) a substrate rotation device that is provided on any one of substrate processing routes to the post-exposure bake unit after the exposure, and rotates the substrate. Moving means; and (b) a rotation control means for controlling the substrate rotation means, wherein the rotation control means has an effect on a line width of a temperature gradient generated in the substrate in the pre-exposure baking. The orientation of the substrate in the pre-exposure bake section and the orientation of the substrate in the post-exposure bake section are set such that the influence of the temperature gradient generated on the substrate in the post-exposure bake on the line width is offset. Set the relative angle to the It is made to adjust to.
[0009]
According to a second aspect of the present invention, in the substrate processing apparatus according to the first aspect of the present invention, the rotation control means adjusts the relative angle in accordance with a type of resist applied to the substrate and a resist film thickness. .
[0010]
According to a third aspect of the present invention, in the substrate processing apparatus according to the second aspect of the present invention, the resist applied to the substrate is a negative resist, and the thickness of the resist applied to the substrate is a resist film thickness. When the line width becomes thicker as the thickness becomes larger, the rotation control means controls the substrate rotation means so that the relative angle becomes 0 °.
[0011]
According to a fourth aspect of the present invention, in the substrate processing apparatus according to the second aspect of the present invention, the resist applied to the substrate is a positive resist, and the thickness of the resist applied to the substrate is a resist film thickness. When the line width becomes thicker as the thickness becomes larger, the rotation control means controls the substrate rotation means so that the relative angle becomes 180 °.
[0012]
According to a fifth aspect of the present invention, in the substrate processing apparatus according to the second aspect of the present invention, the resist applied to the substrate is a negative resist, and the thickness of the resist applied to the substrate is a resist film thickness. If the line width becomes thinner as the thickness becomes larger, the rotation control means controls the substrate rotation means so that the relative angle becomes 180 °.
[0013]
According to a sixth aspect of the present invention, in the substrate processing apparatus according to the second aspect of the present invention, the resist applied to the substrate is a positive resist, and the thickness of the resist applied to the substrate is a resist film thickness. If the line width becomes thinner as the thickness becomes larger, the rotation control means controls the substrate rotation means so that the relative angle becomes 0 °.
[0014]
Further, the invention according to claim 7 includes a pre-exposure bake unit for performing a pre-exposure bake unit for performing a pre-exposure bake process on the substrate before exposure after resist application, and a post-exposure bake unit for performing a post-exposure bake process on the substrate before the post-exposure development. (A) substrate rotating means provided in any one of substrate processing routes to the post-exposure bake unit after the exposure, and for rotating the substrate; b) rotation control means for controlling the substrate rotation means, wherein the rotation control means controls the rotation of the substrate in the pre-exposure bake unit in accordance with the type of resist applied to the substrate and the resist film thickness. The substrate rotating means rotates the substrate so that the carry-in side end is located on the carry-in side or the back side in the post-exposure bake portion.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
<1. Overall Configuration of Substrate Processing Apparatus>
First, the overall configuration of the substrate processing apparatus according to the present invention will be described. FIG. 1 is a diagram showing an overall configuration of a substrate processing apparatus according to the present invention. FIG. 1A is a plan view of the substrate processing apparatus, and FIG. 1B is a front view of the substrate processing apparatus. In FIG. 1, an XYZ orthogonal coordinate system is added to clarify the directional relationship. Here, a horizontal plane parallel to the floor is defined as an XY plane, and a vertical direction is defined as a Z direction.
[0017]
As shown in FIG. 1, in the present embodiment, the substrate processing apparatus includes an indexer ID for carrying in / out a substrate, a plurality of processing units for performing processing on the substrate, and a substrate transport unit for transporting the substrate to each processing unit. It comprises a unit arrangement section MP to be arranged, and an interface IF provided for carrying in / out a substrate between an exposure apparatus (not shown) and the unit arrangement section MP.
[0018]
The unit disposition portion MP includes a chemical cabinet 11 at the lowermost portion for accommodating a pipe or the like for supplying / discharging a processing liquid such as a resist. As processing units, coating processing units SC1 and SC2 (spin coater) that perform resist coating processing while rotating the substrate, and development processing units SD1 and SD2 (spin developer) that perform development processing of the substrate after exposure are arranged. . Above these liquid processing units, a multi-stage heat treatment unit 20 for performing heat treatment on the substrate is disposed at the front and rear of the apparatus. Further, as shown in FIG. 1, between the multi-step heat treatment section 20 on the front side (negative direction side in the Y direction) and the rear side (positive direction side in the Y direction) of the apparatus, an edge of the substrate is provided. EE1 and EE2 are arranged respectively.
[0019]
In the central part of the apparatus sandwiched between the coating processing units SC1 and SC2 and the development processing units SD1 and SD2, all of the surrounding processing units (liquid processing unit, heat treatment unit and edge exposure processing units EE1 and EE2) are accessed and accessed. A transfer robot TR1 is provided as a substrate transfer means for transferring a substrate between the two. The transfer robot TR1 is movable in the vertical direction and is rotatable around a central vertical axis.
[0020]
Note that a filter fan unit FFU that forms a downflow of clean air is installed at the top of the unit arrangement section MP. Further, a filter fan unit FFU for forming a downflow of clean air on the side of the liquid processing section is also provided directly above each of the coating processing sections SC1 and SC2 and the developing processing sections SD1 and SD2.
[0021]
Next, FIG. 2 is a diagram illustrating an arrangement configuration of the processing unit in FIG. Above the coating unit SC1, a three-stage heat treatment unit is disposed as the multi-stage heat treatment unit 20. Among these, a heat treatment section HP1 for performing the heat treatment of the substrate is provided at a position of the second step counted from the lowest step, and a heat treatment section HP2 is similarly provided for the third step. In the lowermost stage, a cooling processing unit CP1 for performing a cooling process on the substrate is provided.
[0022]
A heat treatment unit having a two-stage configuration is disposed above the coating treatment unit SC2 as the multi-stage heat treatment unit 20. Among these, the adhesion strengthening portion AHL1 for performing the adhesion strengthening process on the substrate is provided at the position of the first stage from the lowermost stage, and the adhesion strengthening portion AHL2 is similarly provided for the second stage. Although the uppermost stage is empty in the case of the apparatus of the present embodiment, a heat treatment unit, a cooling treatment unit, or another heat treatment unit can be incorporated according to the application and purpose.
[0023]
Above the development processing unit SD1, a three-stage heat treatment unit is disposed as the multi-stage heat treatment unit 20. Of these, the cooling processing unit CP4 is provided at the position of the first stage from the lowest stage, and the heating processing units HP3 and HP4 are provided at the positions of the second and third stages.
[0024]
Above the development processing unit SD2, a three-stage heat treatment unit is disposed as the multi-stage heat treatment unit 20. Of these, cooling processing units CP2 and CP3 are provided at the first and second stages from the bottom, and at the third stage, post-exposure bake for performing post-exposure bake on the substrate. A plate part PEB is provided.
[0025]
Then, a predetermined process is performed on the substrate by sequentially transporting the substrate between the liquid processing unit, the heat treatment unit, and the edge exposure processing units EE1 and EE2 by the transport robot TR1 provided at the center of the unit arrangement unit MP. be able to.
[0026]
The interface IF has a function of temporarily stocking the substrate on which the resist application has been completed in the unit disposition portion MP so as to pass the substrate to the exposure apparatus or to receive the exposed substrate from the exposure apparatus. Although not shown, the robot includes a robot that transfers a substrate to and from the transport robot TR1, and a buffer cassette that places the substrate. Further, the indexer ID includes a mounting portion for mounting a cassette capable of accommodating a plurality of substrates, and a transfer robot (not shown) for transferring substrates between the cassette and the transfer robot TR1. And a function of paying out unprocessed substrates from the cassette to the transfer robot TR1, and receiving processed substrates from the transfer robot TR1 and storing them in the cassette.
[0027]
Further, the substrate processing apparatus includes a control unit 10. The control unit 10 is configured using a computer, and is electrically connected to the transport robot TR1, the liquid processing unit, the heat treatment unit, and the edge exposure processing units EE1 and EE2, and manages and controls all of the operations.
[0028]
Table 1 below shows an example of substrate processing in this substrate processing apparatus. Such a processing order is input as a recipe in advance, and the control unit 10 causes the transport robot TR1 to transport the substrate according to the recipe.
[0029]
[Table 1]

[0030]
According to this processing order, the unprocessed substrate is paid out from the indexer ID, and after the adhesion strengthening processing, the cooling processing, and the resist coating processing are performed, the pre-baking is performed in the heating processing unit HP1 (processing sequence ▲). 5 ▼). After that, after the cooling process, it is transferred to the exposure apparatus via the interface IF and is subjected to the exposure process (processing order {circle around (7)}). The exposed substrate is returned to the unit arrangement section MP via the interface IF, and after the edge exposure is performed in the edge exposure processing section EE1 (processing order {circle around (8)}), the post-exposure bake plate section PEB is processed. After the exposure, baking is performed (processing order [9]), and thereafter, cooling processing and development processing are performed, and the substrate is returned to the indexer ID again as a processed substrate. That is, in the present embodiment, the heat treatment section HP1 corresponds to a pre-exposure bake section, and the post-exposure bake plate section PEB corresponds to a post-exposure bake section.
[0031]
In Table 1, the processing units shown in parentheses indicate the processing units where parallel processing is performed. That is, since the required time in each processing step is not the same, two equivalent processing units are allocated to the step having a long required time, and the processing is performed in any one of them. For example, the unprocessed substrate paid out from the indexer ID is carried into the vacant one of the adhesion strengthening part AHL1 and the adhesion reinforcement part AHL2, and the substrate on which the resist coating processing has been completed is subjected to the heat treatment part HP1 or the heat treatment part HPL. This is carried into one of the units HP2 and prebaked. Therefore, the heat treatment section HP2 also corresponds to a pre-exposure bake section. However, in this specification, for ease of understanding, it is assumed that the substrate is sequentially transported to processing units other than the processing units indicated by parentheses in Table 1 to perform a series of substrate processing.
[0032]
<2. Substrate orientation in pre-bake and post-exposure bake>
In the processing sequence shown in Table 1, in the steps (processing sequence (1) to (7)) after the substrate is paid out from the indexer ID and passed to the interface IF, the direction of the substrate in each processing unit is the same. is there. That is, the procedure is repeated in which the substrate carried into each processing unit in a predetermined direction is carried out in the same direction, and carried into the next processing unit in the same direction. Note that the coating processing unit SC1 performs the resist coating while rotating the substrate. However, since the rotation is stopped in the same direction as the direction of the substrate before rotation, the directions of the substrate before and after the processing are the same. Become.
[0033]
Incidentally, the substrate is usually provided with an orientation flat or notch indicating its crystal orientation, and the orientation of the substrate is recognized by optically detecting such an orientation flat or notch. Also in this embodiment, in order to detect the orientation of the substrate in the process from when the substrate is paid out from the indexer ID to when it is passed to the interface IF, any one of the processes from the adhesion strengthening unit AHL1 to the cooling unit CP2 is detected. The unit is provided with a mechanism for optically detecting the orientation flat or notch of the substrate and detecting the orientation thereof. Instead of providing an optical detection mechanism in any of the processing units from the adhesion strengthening unit AHL1 to the cooling processing unit CP2, a processing unit dedicated to optical detection may be provided in the substrate processing apparatus. Then, the detected orientation of the substrate before the exposure processing is transmitted to the control unit 10 and stored.
[0034]
Next, the substrate is passed to the exposure apparatus that performs the exposure processing, and the exposure apparatus performs the processing by rotating the substrate in an optimal direction for the exposure processing regardless of the orientation of the substrate before the exposure processing. Is passed to the step after the exposure processing in that direction. Therefore, there is a high possibility that the direction of the substrate carried into the edge exposure processing unit EE1 is different from the direction of the substrate in the pre-exposure process.
[0035]
Here, in the present embodiment, the control unit 10 gives an instruction to the edge exposure processing unit EE1 while referring to the orientation of the substrate before the exposure processing, and the edge exposure processing unit EE1 rotates the substrate based on the instruction. The substrate is carried out with the direction of the substrate being the same as the direction of the substrate in the pre-exposure processing step or the direction rotated by 180 °. Therefore, in the present embodiment, the edge exposure processing unit EE1 (EE2) corresponds to the substrate rotation unit, and the control unit 10 corresponds to the rotation control unit.
[0036]
FIG. 6 is a plan view schematically showing an outline of the edge exposure processing unit EE1. In the first place, the edge exposure processing unit EE1 rotates the substrate by rotating the substrate while irradiating the substrate edge with light from the exposure unit 50 to remove the resist film at the edge of the substrate W. , A processing unit that exposes the entire edge of the substrate W. In general, the edge exposure processing unit EE1 performs edge exposure while recognizing the rotation angle of the substrate by causing the edge sensor 52 to optically detect the orientation flat 55 (or notch). That is, the edge exposure processing unit EE1 includes the driving unit 51 for rotating the substrate and the edge sensor 52 as a mechanism for detecting the rotation angle of the substrate in order to perform edge exposure. In the present embodiment, the edge exposure processing unit EE1 adjusts the orientation of the substrate in accordance with an instruction from the control unit 10 by using such inherent functions.
[0037]
The substrate whose edge has been exposed and whose orientation has been adjusted is transferred to the post-exposure bake plate unit PEB in the same orientation after the adjustment. In the process from the post-exposure bake plate portion PEB to the transfer to the indexer ID, the orientation of the substrate in each processing portion is the same as in the pre-exposure process.
[0038]
As described above, in the present embodiment, the control unit 10 controls the edge exposure processing unit EE1, and determines the orientation of the substrate in the heating processing unit HP1 as the pre-exposure bake unit and the post-exposure bake plate unit PEB as the post-exposure bake unit. The direction of the substrate is adjusted by the edge exposure processing unit EE1 so that the relative angle between the substrate and the direction of the substrate becomes 0 ° or 180 °.
[0039]
FIG. 7 is a plan view schematically showing the outline of the post-exposure bake plate portion PEB. Referring to the drawing, the above can be further extended. When the end WE of the substrate W at the entrance side of the heat treatment section HP1 as the pre-exposure bake section is located at the entrance side IP or at the depth at the post-exposure bake plate section PEB as the post-exposure bake section. That is, the control unit 10 rotates the substrate W to the edge exposure processing unit EE1 so as to be positioned on the side OP (in the case of FIG. 7, the post-exposure bake plate is used for the carry-in entrance end WE of the heating processing unit HP1). The part PEB is located on the back side OP). Note that the carry-in side IP in the post-exposure bake plate part PEB is the side closest to the carry-in port 60 provided in the post-exposure bake plate part PEB for the transfer robot TR1 to access. The side farthest from the mouth 60. The same definition applies to the carry-in side and the back side in the heat treatment section HP1. In addition, the carry-in side end WE of the substrate W in the heat treatment unit HP1 is an end of the substrate W located on the carry-in side closest to the carry-in entrance of the heat treatment unit HP1.
[0040]
Incidentally, whether the relative angle is set to 0 ° or 180 ° is determined by the type of the resist and the target film thickness of the resist.
[0041]
As is well known, there are two types of resists, a positive resist in which exposed portions are dissolved by a developer, and a negative resist in which exposed portions remain after development. Further, the target film thickness of the resist applied to the substrate in the coating processing units SC1 and SC2 differs depending on the characteristics required for the final product such as a semiconductor chip. The type of the resist and the target film thickness of the resist are input to the control unit 10 in advance, and the control unit 10 refers to the information and, based on the type of the resist and the target film thickness of the resist, sets the relative position. It is determined whether the angle is 0 ° or 180 °, and the edge exposure processing unit EE1 adjusts the direction of the substrate. The determination of the relative angle based on the type of the resist and the target film thickness of the resist is specifically performed as follows.
[0042]
<2-1. First pattern>
FIG. 3 is a diagram showing a correlation between the resist film thickness and the resist line width after development. As shown in the figure, the correlation between the resist film thickness and the developed resist line width can be classified into two patterns with the film thickness TH as a boundary when focusing on a film thickness near the film thickness TH. it can. That is, when the film thickness of the resist applied to the substrate is larger than the film thickness TH, the positive characteristic that the resist line width becomes larger as the film thickness of the resist is larger, and when the film thickness is smaller than the film thickness TH, The negative characteristic that the resist line width becomes narrower as the resist film thickness increases is recognized. The correlation between the resist film thickness and the resist line width is the same regardless of the type of the resist.
[0043]
Here, the case where the target film thickness of the resist is A which is larger than the film thickness TH and the type of the resist is a negative resist will be described first as the first pattern.
[0044]
As described above, in the heat treatment section HP1 and the post-exposure bake plate section PEB, the carry-in side accessed by the transport robot TR1 is more easily exposed to the outside air than the back side, and the carry-in side in pre-bake and post-exposure bake. A temperature gradient occurs in which the temperature of the substrate is slightly lower than the temperature on the back side. In other words, a similar temperature gradient occurs in which the temperature increases from the carry-in side toward the back side in both the heat treatment section HP1 and the post-exposure bake plate section PEB.
[0045]
The pre-bake is performed in order to evaporate an excess solvent component in the resist applied in the coating processing unit SC1 and to strengthen the adhesiveness between the resist and the substrate. There is a difference in the degree of evaporation of the components, and the degree of evaporation of the solvent components is higher at the back side where the temperature is higher than at the entrance side. As a result, the resist film thickness on the carry-in side where evaporation of the solvent component is small is larger than the resist film thickness on the back side.
[0046]
When the target film thickness of the resist is the film thickness A, as shown in FIG. 3, the resist line width becomes larger as the resist film thickness increases in the vicinity of the film thickness A. The resist line width is larger than the resist line width on the back side. That is, when the target film thickness of the resist is the film thickness A, the temperature dependency on the resist line width in the pre-bake in the heat treatment section HP1 is such that the resist line width becomes narrower as the temperature increases. The resist line width on the side of the entrance where the temperature is low is larger than the resist line width on the back side.
[0047]
On the other hand, in the post-exposure bake in the post-exposure bake plate portion PEB, if a temperature gradient occurs in the substrate, a difference occurs in the activity of the acid which is a product of the photochemical reaction at the time of exposure. In other words, the higher the temperature is, the greater the acid activity is. Therefore, the acid activity is higher on the back side where the temperature is higher than on the carry-in side.
[0048]
When the type of the resist is a negative resist, as the acid activity increases, the degree of curing of the resist in the exposed portion increases, and as a result, the resist line width increases. Therefore, the resist line width on the back side having a large acid activity is larger than the resist line width on the carry-in side. In other words, when the type of the resist is a negative resist, the temperature dependency on the resist line width in the post-exposure bake in the post-exposure bake plate portion PEB is a characteristic that the resist line width increases as the temperature increases. In other words, the resist line width on the carry-in side where the temperature is low is narrower than the resist line width on the back side.
[0049]
As described above, in both the heat treatment section HP1 and the post-exposure bake plate section PEB, a similar temperature gradient occurs in which the temperature increases from the carry-in side to the back side. In the first pattern, the temperature dependence on the resist line width in the pre-bake and the temperature dependence on the resist line width in the post-exposure bake have opposite characteristics. If the orientation of the substrate in the bake plate portion PEB is the same, the effect of the temperature gradient generated on the substrate in the pre-bake on the line width and the effect on the line width of the substrate in the post-exposure bake are offset. As a result, the final resist line width uniformity is improved.
[0050]
Therefore, in the first pattern, if the direction of the substrate is adjusted so that the relative angle between the direction of the substrate in the heat treatment section HP1 and the direction of the substrate in the post-exposure bake plate section PEB becomes 0 °, the development can be performed. The uniformity of the resist line width after the processing can be improved. Conversely, when the orientation of the substrate is adjusted so that the relative angle becomes 180 °, the influence of the temperature gradient generated on the substrate in pre-bake on the line width and the temperature gradient generated on the substrate in post-exposure bake on the line width In addition, the uniformity of the resist line width after the development processing is significantly deteriorated.
[0051]
<2-2. Second pattern>
Next, the case where the target film thickness of the resist is A which is larger than the film thickness TH and the type of the resist is a positive resist will be described as a second pattern.
[0052]
As in the case of the first pattern, the target film thickness of the resist is the film thickness A. Therefore, the temperature dependency on the resist line width in the pre-bake in the heat treatment section HP1 is such that the resist line width increases as the temperature increases. The resist line width is narrower, and the resist line width on the lower entrance side is wider than the resist line width on the far side.
[0053]
On the other hand, in the post-exposure bake in the post-exposure bake plate portion PEB, when a temperature gradient occurs in the substrate, a difference occurs in the activity of the acid which is a product of the photochemical reaction at the time of exposure, and the higher the temperature, the larger the acid activity becomes. Therefore, the acid activity is higher on the back side where the temperature is higher than on the carry-in side, as in the first pattern.
[0054]
In the second pattern, since the type of the resist is a positive resist, when the acid activity increases, the extent to which the exposed portion is dissolved by the developing solution increases, and as a result, the resist line width decreases. Therefore, the resist line width on the back side having a large acid activity is smaller than the resist line width on the carry-in side. That is, when the type of the resist is a positive resist, the temperature dependency on the resist line width in the post-exposure bake in the post-exposure bake plate portion PEB is a characteristic that the resist line width becomes narrower as the temperature increases. In other words, the resist line width on the lower entrance side is larger than the resist line width on the far side.
[0055]
In both the heat treatment section HP1 and the post-exposure bake plate section PEB, a similar temperature gradient occurs in which the temperature increases from the carry-in side to the back side. In the second pattern, the temperature dependence on the resist line width in the pre-bake and the temperature dependence on the resist line width in the post-exposure bake have the same characteristics. By reversing the direction of the substrate in the bake plate portion PEB, the effect of the temperature gradient generated on the substrate in the pre-bake on the line width is offset by the effect of the temperature gradient generated on the substrate on the line width in the post-exposure bake. As a result, the final resist line width uniformity is improved.
[0056]
Therefore, in the second pattern, if the direction of the substrate is adjusted so that the relative angle between the direction of the substrate in the heat treatment unit HP1 and the direction of the substrate in the post-exposure bake plate unit PEB is 180 °, the development can be performed. The uniformity of the resist line width after the processing can be improved. Conversely, when the orientation of the substrate is adjusted so that the relative angle becomes 0 °, the influence of the temperature gradient generated on the substrate in pre-bake on the line width and the temperature gradient generated on the substrate in post-exposure bake on the line width are reduced. In addition, the uniformity of the resist line width after the development processing is significantly deteriorated.
[0057]
<2-3. Third pattern>
Next, the case where the target film thickness of the resist is B smaller than the film thickness TH and the type of the resist is a negative resist will be described as a third pattern.
[0058]
If a temperature gradient occurs on the substrate, the degree of evaporation of the solvent component will be different, and the higher temperature side will have a greater degree of evaporation of the solvent component than the carry-in side and will have less evaporation of the solvent component. The fact that the thickness of the resist is larger than the thickness of the resist on the back side is the same as in the first pattern.
[0059]
In the case where the target film thickness of the resist is the film thickness B, as shown in FIG. 3, in the vicinity of the film thickness B, as the resist film thickness increases, the resist line width becomes narrower. The resist line width is smaller than the resist line width on the back side. That is, when the target film thickness of the resist is the film thickness B, the temperature dependency on the resist line width in the pre-bake in the heat treatment section HP1 is a characteristic that the resist line width increases as the temperature increases. The resist line width on the side of the entrance where the temperature is low is smaller than the resist line width on the back side.
[0060]
On the other hand, in the post-exposure bake in the post-exposure bake plate part PEB, as in the case of the first pattern, since the type of the resist is a negative resist, the temperature dependence on the resist line width is such that the temperature increases. Therefore, the resist line width is large, and the resist line width on the carry-in side where the temperature is low is smaller than the resist line width on the back side.
[0061]
Therefore, in the third pattern, the temperature dependency on the resist line width in the pre-bake and the temperature dependency on the resist line width in the post-exposure bake have the same characteristics. By reversing the direction of the substrate in the bake plate portion PEB, the effect of the temperature gradient generated on the substrate in the pre-bake on the line width is offset by the effect of the temperature gradient generated on the substrate on the line width in the post-exposure bake. As a result, the final resist line width uniformity is improved.
[0062]
Therefore, in the third pattern, if the direction of the substrate is adjusted so that the relative angle between the direction of the substrate in the heat treatment unit HP1 and the direction of the substrate in the post-exposure bake plate unit PEB is 180 °, the development can be performed. The uniformity of the resist line width after the processing can be improved. Conversely, when the orientation of the substrate is adjusted so that the relative angle becomes 0 °, the influence of the temperature gradient generated on the substrate in pre-bake on the line width and the temperature gradient generated on the substrate in post-exposure bake on the line width are reduced. In addition, the uniformity of the resist line width after the development processing is significantly deteriorated.
[0063]
<2-4. Fourth pattern>
Next, a case where the target film thickness of the resist is B smaller than the film thickness TH and the type of the resist is a positive resist will be described as a fourth pattern.
[0064]
Similarly to the third pattern, the target film thickness of the resist is the film thickness B. Therefore, the temperature dependency on the resist line width in the pre-bake in the heat treatment section HP1 is such that the resist line width increases as the temperature increases. The width of the resist line on the loading entrance side where the temperature is low is smaller than the width of the resist line on the back side.
[0065]
On the other hand, in the post-exposure bake in the post-exposure bake plate portion PEB, as in the case of the second pattern, since the type of resist is a positive resist, the temperature dependency on the resist line width becomes higher as the temperature increases. Therefore, the resist line width is small, and the resist line width on the carry-in side where the temperature is low is larger than the resist line width on the back side.
[0066]
Therefore, in the fourth pattern, the temperature dependency on the resist line width in the pre-bake and the temperature dependency on the resist line width in the post-exposure bake have opposite characteristics. If the orientation of the substrate in the bake plate portion PEB is the same, the effect of the temperature gradient generated on the substrate in the pre-bake on the line width and the effect on the line width of the substrate in the post-exposure bake are offset. As a result, the final resist line width uniformity is improved.
[0067]
Therefore, in the fourth pattern, if the direction of the substrate is adjusted so that the relative angle between the direction of the substrate in the heat treatment unit HP1 and the direction of the substrate in the post-exposure bake plate unit PEB becomes 0 °, the development can be performed. The uniformity of the resist line width after the processing can be improved. Conversely, when the orientation of the substrate is adjusted so that the relative angle becomes 180 °, the influence of the temperature gradient generated on the substrate in pre-bake on the line width and the temperature gradient generated on the substrate in post-exposure bake on the line width In addition, the uniformity of the resist line width after the development processing is significantly deteriorated.
[0068]
<2-5. Summary>
As described above, the target film thickness of the resist affects the temperature dependency on the resist line width in the pre-bake in the heat treatment section HP1. Table 2 below summarizes the contents.
[0069]
[Table 2]

[0070]
As a result of the temperature gradient occurring in the substrate in the pre-bake in the heat treatment section HP1, a line width difference t occurs between the resist line width on the carry-in side and the resist line width on the back side.
[0071]
On the other hand, the type of the resist affects the temperature dependency on the resist line width in the post-exposure bake in the post-exposure bake plate portion PEB. Table 3 below summarizes the contents.
[0072]
[Table 3]

[0073]
As a result of a temperature gradient occurring in the substrate during the post-exposure bake in the post-exposure bake plate portion PEB, a line width difference T occurs between the resist line width on the carry-in side and the resist line width on the back side. Note that T> t because the temperature dependency in the post-exposure bake is greater than the temperature dependency in the pre-bake.
[0074]
As described above, there are four combinations of conditions depending on whether the target film thickness of the resist is thicker or thinner than the film thickness TH, and whether the type of the resist is a positive resist or a negative resist. The effect of the temperature gradient generated on the substrate on the line width is offset by the effect of the temperature gradient generated on the substrate on the line width in the post-exposure bake.
[0075]
FIG. 4 is a diagram showing the line width uniformity when the type of the resist is a negative resist. The horizontal axis of the figure shows the position of the substrate in the post-exposure bake plate portion PEB.
[0076]
In the case where the type of the resist is a negative resist, when the target film thickness of the resist is A which is larger than the film thickness TH (first pattern), the orientation of the substrate in the heat treatment part HP1 and the bake plate part PEB after the exposure. If the direction of the substrate is adjusted so that the relative angle with the direction of the substrate becomes 0 °, the influence of the temperature gradient on the line width is canceled out, and the line width difference becomes Tt (see FIG. 4). solid line). Conversely, if the direction of the substrate is adjusted so that the relative angle becomes 180 °, the effect of the temperature gradient on the line width is added, and the line width difference becomes T + t (dotted line in FIG. 4).
[0077]
When the resist type is a negative resist and the target film thickness of the resist is B smaller than the film thickness TH (third pattern), the orientation of the substrate in the heat treatment section HP1 and the post-exposure bake plate section If the direction of the substrate is adjusted so that the relative angle of the PEB with the direction of the substrate becomes 180 °, the influence of the temperature gradient on the line width is offset, and the line width difference becomes Tt (FIG. 4). Solid line inside). Conversely, if the direction of the substrate is adjusted so that the relative angle becomes 0 °, the effect of the temperature gradient on the line width is added, and the line width difference becomes T + t (dotted line in FIG. 4).
[0078]
FIG. 5 is a diagram showing the line width uniformity when the type of the resist is a positive resist. As in FIG. 4, the horizontal axis in FIG. 5 indicates the position of the substrate in the post-exposure bake plate portion PEB.
[0079]
In the case where the type of the resist is a positive resist, when the target film thickness of the resist is A which is larger than the film thickness TH (second pattern), the orientation of the substrate in the heat treatment section HP1 and the post-exposure bake plate section PEB. If the direction of the substrate is adjusted so that the relative angle to the direction of the substrate becomes 180 °, the effect of the temperature gradient on the line width is canceled out, and the line width difference becomes Tt (see FIG. 5). solid line). Conversely, if the direction of the substrate is adjusted so that the relative angle becomes 0 °, the effect of the temperature gradient on the line width is added, and the line width difference becomes T + t (dotted line in FIG. 5).
[0080]
When the resist type is a positive resist and the target film thickness of the resist is B smaller than the film thickness TH (fourth pattern), the orientation of the substrate in the heat treatment section HP1 and the post-exposure bake plate section If the orientation of the substrate is adjusted so that the relative angle of the PEB with the orientation of the substrate becomes 0 °, the effect of the temperature gradient on the line width is canceled out, and the line width difference becomes Tt (FIG. 5). Solid line inside). Conversely, when the direction of the substrate is adjusted so that the relative angle becomes 180 °, the effect of the temperature gradient on the line width is added, and the line width difference becomes T + t (dotted line in FIG. 5).
[0081]
<3. Modification>
The embodiments of the present invention have been described above, but the present invention is not limited to the above examples. For example, in the above embodiment, the edge exposure processing unit EE1 adjusts the direction of the substrate. However, the present invention is not limited to this. A driving unit that rotates the substrate and a mechanism that detects the rotation angle of the substrate are used. May be provided with a substrate rotation processing unit dedicated to angle adjustment having the following. Further, when transferring the exposed substrate from the interface IF to the transfer robot TR1, the position of the transfer robot provided in the interface IF in the Y direction is changed to change the substrate transfer angle to the transfer robot TR1, and the direction of the substrate is changed. May be adjusted. In other words, after the exposure, the substrate orientation in the heat processing unit HP1 and the substrate orientation in the post-exposure bake plate unit PEB are provided in any of the substrate processing routes up to the post-exposure bake plate unit PEB. Any means may be used as long as the relative angle between them can be made 0 ° or 180 °.
[0082]
Further, in the above embodiment, the orientation of the substrate in the heat treatment section HP1 as the pre-exposure bake section and the direction of the post-exposure bake plate section PEB as the post-exposure bake section are determined according to the type of the resist and the target thickness of the resist. The orientation of the substrate is adjusted so that the relative angle with the orientation of the substrate is 0 ° or 180 °. Although an example was shown in which the temperature gradient generated at the time of offsetting the influence on the line width was shown, the present invention is not limited to this. Has a desired relative angle (that is, the relative angle is 0 ° or 18) that can offset the effect of the temperature on the line width and the effect of the temperature gradient generated on the substrate in the post-exposure bake on the line width. The directions of the substrate in the heat treatment unit HP1 as the pre-exposure bake unit and the directions of the substrates in the post-exposure bake plate unit PEB as the post-exposure bake unit are adjusted so as to include a case where the angle is shifted by a predetermined angle from ゜. It may be.
[0083]
【The invention's effect】
As described above, according to any one of the first to sixth aspects of the present invention, the influence of the temperature gradient generated on the substrate in the pre-exposure baking process on the line width and the effect of the temperature gradient generated on the substrate in the post-exposure baking process Since the relative angle between the direction of the substrate in the bake section before exposure and the direction of the substrate in the bake section after exposure is adjusted by the substrate rotating means so that the influence of the temperature gradient on the line width is offset. In addition, the line width uniformity of the resist film on the substrate after the development processing can be improved.
[0084]
Further, according to the invention of claim 7, the entrance side end of the substrate in the pre-exposure bake section is the entrance side or the back side in the post-exposure bake section, depending on the type of resist applied to the substrate and the resist film thickness. Since the substrate is rotated so as to be positioned at a position, the temperature gradient generated in the substrate in the pre-exposure baking affects the line width and the temperature gradient generated in the substrate in the post-exposure baking corresponds to the line width. The influence of the influence is offset, and the same effect as the first aspect of the invention can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a substrate processing apparatus according to the present invention.
FIG. 2 is a diagram illustrating an arrangement configuration of a processing unit in the substrate processing apparatus of FIG.
FIG. 3 is a diagram showing a correlation between a resist film thickness and a resist line width after development.
FIG. 4 is a diagram showing line width uniformity when the type of resist is a negative resist.
FIG. 5 is a diagram illustrating line width uniformity when the type of resist is a positive resist.
FIG. 6 is a plan view schematically showing an outline of an edge exposure processing unit.
FIG. 7 is a plan view schematically showing an outline of a post-exposure bake plate portion.
[Explanation of symbols]
10 control unit
EE1, EE2 Edge exposure processing unit
HP1, HP2 Heat treatment section
PEB Bake plate after exposure

Claims (7)

A pre-exposure bake unit that performs pre-exposure bake processing on the substrate before exposure after resist coating, and a post-exposure bake unit that performs post-exposure bake processing on the substrate before development after exposure,
(A) substrate rotating means provided on any of the substrate processing routes to the post-exposure bake unit after the exposure, and for rotating the substrate;
(B) rotation control means for controlling the substrate rotation means;
With
The rotation control unit cancels out the effect of the temperature gradient generated on the substrate in the pre-exposure baking process on the line width and the effect of the temperature gradient generated on the substrate in the post-exposure baking process on the line width. As described above, the substrate processing apparatus is characterized in that the substrate rotating means adjusts the relative angle between the direction of the substrate in the pre-exposure bake section and the direction of the substrate in the post-exposure bake section. The substrate processing apparatus according to claim 1,
The substrate processing apparatus, wherein the rotation control means adjusts the relative angle according to a type of resist applied to the substrate and a resist film thickness. The substrate processing apparatus according to claim 2,
When the resist applied to the substrate is a negative resist, and in the film thickness of the resist applied to the substrate, the line width becomes thicker as the resist film thickness increases,
The substrate processing apparatus, wherein the rotation control means controls the substrate rotation means so that the relative angle becomes 0 °. The substrate processing apparatus according to claim 2,
When the resist applied to the substrate is a positive resist, and in the thickness of the resist applied to the substrate, if the line width becomes thicker as the resist film thickness increases,
The substrate processing apparatus, wherein the rotation control means controls the substrate rotation means so that the relative angle is 180 °. The substrate processing apparatus according to claim 2,
When the resist applied to the substrate is a negative resist, and in the film thickness of the resist applied to the substrate, the line width becomes thinner as the resist film thickness increases,
The substrate processing apparatus, wherein the rotation control means controls the substrate rotation means so that the relative angle is 180 °. The substrate processing apparatus according to claim 2,
When the resist applied to the substrate is a positive resist, and in the film thickness of the resist applied to the substrate, the line width becomes thinner as the resist film thickness increases,
The substrate processing apparatus, wherein the rotation control means controls the substrate rotation means so that the relative angle becomes 0 °. A pre-exposure bake unit that performs pre-exposure bake processing on the substrate before exposure after resist coating, and a post-exposure bake unit that performs post-exposure bake processing on the substrate before development after exposure,
(A) substrate rotating means provided on any of the substrate processing routes to the post-exposure bake unit after the exposure, and for rotating the substrate;
(B) rotation control means for controlling the substrate rotation means;
With
The rotation control means, depending on the type of resist applied to the substrate and the resist film thickness, the entrance side end of the substrate in the pre-exposure bake section to the entrance side or the back side in the post-exposure bake section A substrate processing apparatus, wherein the substrate is rotated by the substrate rotating means so as to be positioned.

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