JP2006339347A

JP2006339347A - Reticle chuck

Info

Publication number: JP2006339347A
Application number: JP2005161309A
Authority: JP
Inventors: Atsushi Kimura; 篤史木村
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 2005-06-01
Filing date: 2005-06-01
Publication date: 2006-12-14

Abstract

<P>PROBLEM TO BE SOLVED: To stably hold a reticle by suppressing the deformation thereof due to dust biting. <P>SOLUTION: The reticle chuck includes a first holder for holding the reticle in right posture, a second holder arranged around the first holder, and an elastic member for sealing which has a resiliency in a direction perpendicular to the pattern plane of the reticle and is arranged around the second holder. The top face of the elastic member for sealing which is in contact with the rear face of the reticle is formed of a material having a small sticking property. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は半導体露光装置に用いられる、レチクルチャックに関するものである。 The present invention relates to a reticle chuck used in a semiconductor exposure apparatus.

半導体製造のフォトリソ工程には、レチクルの微細パターンを感光剤の塗布されたウェハー上に転写する露光装置が使用されている。半導体露光装置は色々な方式のものがあるが、最近はスリットあるいは円弧状の照明光をレチクルに照射し、スリットの長手方向は投影光学系の縮小倍率（例えば４：１）で露光を行い、短手方向はレチクルとウェハーを投影光学系の縮小倍率比で同期を取りながら露光する、いわゆるステップ・アンド・スキャン方式を採用した走査型露光装置が主流である。ステップ・アンド・スキャン方式では、レチクルおよびウェハーは各ショットごとに停止と移動による加減速を繰り返す。この時生じる加速度と基板の質量に応じた力が基板（レチクルやウェハー）にかかるため、この力に耐え得る程度の保持力で基板をステージに保持する必要がある。通常は真空吸着力で基板をステージに吸着保持している。 An exposure apparatus that transfers a fine pattern of a reticle onto a wafer coated with a photosensitive agent is used in a photolithography process of semiconductor manufacturing. There are various types of semiconductor exposure apparatuses. Recently, a slit or arc-shaped illumination light is irradiated onto a reticle, and the longitudinal direction of the slit is exposed at a reduction magnification (for example, 4: 1) of the projection optical system. In the short-side direction, a scanning exposure apparatus adopting a so-called step-and-scan method in which a reticle and a wafer are exposed while being synchronized with a reduction magnification ratio of a projection optical system is the mainstream. In the step-and-scan method, the reticle and wafer are repeatedly accelerated and decelerated by stopping and moving for each shot. Since a force corresponding to the acceleration generated at this time and the mass of the substrate is applied to the substrate (reticle or wafer), it is necessary to hold the substrate on the stage with a holding force that can withstand this force. Usually, the substrate is sucked and held on the stage by vacuum suction force.

特にレチクルステージはウェハーステージに比べて大きな速度（例えば４倍の速度）で走査する必要があり、これに伴って加速度もレチクルステージの方が大きくなるため、レチクルの保持をしっかり行なわなければならない。 In particular, the reticle stage needs to be scanned at a higher speed (for example, four times faster) than the wafer stage, and accordingly, the acceleration of the reticle stage is larger, so that the reticle must be firmly held.

図６はレチクルＲの保持機構を示す概略斜視図であり、レチクル天板１にセラミックからなるレチクルチャックベース２が搭載され、その４ヶ所にセラミックからなる真空吸着部３が設けられている。図７、８および９はそれぞれ真空吸着部３の拡大斜視図、拡大平面図、拡大断面図を示す。これらの図に示すように真空吸着部３は、外枠３１、複数の内部ピン３２で構成され、吸引穴３４からエアを吸引することによって、領域３３を真空にしてレチクルＲを保持している。ここで、外枠３１と内部ピン３２の上面は同一平面に仕上げており、レチクルＲの下面が密着したときのレチクルＲの平坦度を補償している。また、外枠３１は幅を充分にとることで、シール機能を持たせて領域３３に外気が浸入して真空を破ることがないようにし、かつ吸着保持したときの摩擦力を確保してレチクルステージの加速時にレチクルＲがずれるのを防いでいる。 FIG. 6 is a schematic perspective view showing a holding mechanism for the reticle R, in which a reticle chuck base 2 made of ceramic is mounted on the reticle top plate 1, and vacuum suction portions 3 made of ceramic are provided at four places. 7, 8 and 9 show an enlarged perspective view, an enlarged plan view and an enlarged sectional view of the vacuum suction part 3, respectively. As shown in these drawings, the vacuum suction section 3 is composed of an outer frame 31 and a plurality of internal pins 32, and sucks air from the suction holes 34 to evacuate the region 33 and hold the reticle R. . Here, the upper surfaces of the outer frame 31 and the inner pins 32 are finished in the same plane, and the flatness of the reticle R when the lower surface of the reticle R is in close contact is compensated. In addition, the outer frame 31 has a sufficient width so as to have a sealing function so that the outside air does not enter the region 33 and break the vacuum, and also ensures a frictional force when held by suction and the reticle. The reticle R is prevented from shifting when the stage is accelerated.

なお内部ピン３２がないと、レチクルＲは図１０のように真空吸着部３の内側でＲ’のように変形し、平坦度が悪化してしまうため、それを避けるために設けている。 Without the internal pin 32, the reticle R is deformed like R 'inside the vacuum suction portion 3 as shown in FIG. 10, and the flatness deteriorates.

又、従来例としては、例えば特許文献１と特許文献２をあげることが出来る。
特開昭６２−１００７５３号公報特開２００１−３３２４８０号公報 Moreover, as a prior art example, patent document 1 and patent document 2 can be mention | raise | lifted, for example.
JP-A-62-100753 JP 2001-332480 A

ところが、このような構成にすると、図１１のようにゴミ４が外枠３１とレチクルＲとの間に入り込んでしまうと、外枠３１はセラミックのような高剛性材料からなっているため、レチクルＲは変形が生じ（Ｒ’）、ディストーションの原因になってしまう。 However, with such a configuration, if the dust 4 enters between the outer frame 31 and the reticle R as shown in FIG. 11, the outer frame 31 is made of a highly rigid material such as ceramic. R is deformed (R ′) and causes distortion.

上記の課題を解決するために本発明のレチクルチャックは、レチクルの姿勢を保持する第１の保持部と、第１の保持部の周囲に配置された第２の保持部と、第２の保持部の周囲にレチクルのパターン面と直交する方向、すなわち厚さ方向にバネ性を有するシール用弾性部材を設けることで、レチクルをゴミかみによる変形を抑えて安定した保持を実現し、ディストーションを低減することができる。 In order to solve the above problems, a reticle chuck according to the present invention includes a first holding unit that holds the posture of the reticle, a second holding unit that is disposed around the first holding unit, and a second holding unit. By providing an elastic member for sealing that has spring properties in the direction perpendicular to the reticle pattern surface, that is, in the thickness direction, the reticle is held in a stable state by suppressing deformation due to dust and reducing distortion. can do.

以上説明したように本発明によれば、レチクルチャックにおいて保持部の周囲に、レチクルのパターン面と直交する方向の剛性が低く、レチクルとの吸着面は金属、テフロン（登録商標）コーティングおよびニッケルメッキなど固着しにくい材料であるシール用部材を設けることで、ゴミかみによるレチクルの平坦度の悪化を抑制し、ディストーションを低減した露光装置を提供することができる。 As described above, according to the present invention, the rigidity in the direction orthogonal to the pattern surface of the reticle is low around the holding portion in the reticle chuck, and the adsorption surface with the reticle is made of metal, Teflon (registered trademark), and nickel plating. By providing a sealing member that is a material that is difficult to adhere, it is possible to provide an exposure apparatus that suppresses deterioration of reticle flatness due to dust and reduces distortion.

以下、図１ないし図５を参照して本発明による改良されたレチクルチャックの実施の形態について説明する。 Hereinafter, an embodiment of an improved reticle chuck according to the present invention will be described with reference to FIGS.

図１から図３は本発明にかかわるレチクルチャックの第１実施例を示す概略図で、図１は真空吸着部１３の拡大斜視図、図２は拡大断面図、図３はレチクルＲ吸着時の拡大断面図である。 1 to 3 are schematic views showing a first embodiment of a reticle chuck according to the present invention. FIG. 1 is an enlarged perspective view of a vacuum suction portion 13, FIG. 2 is an enlarged sectional view, and FIG. It is an expanded sectional view.

真空吸着部１０３は、外枠１３１、複数の内部ピン１３２およびシール用部材１３５で構成され、吸引穴１３４からエアを吸引することによって、領域１３３を真空にしてレチクルＲを吸着保持している。外枠１３１および内部ピン１３２はセラミックのような高剛性材料からなり、シール用部材１３５はゴムからなる低弾性部材１３５ｂの上面に金属の薄板１３５ａが接着あるいは接合されている。このような構成にすると、レチクルＲは外枠１３１と内部ピン１３２だけでなく、シール用部材１３５にも密着するため、摩擦による保持力が大きくなる。その分外枠１３１の幅を減じることができ、外枠１３１とレチクルＲの間にゴミが入り込む確率が低くなる。また、シール用部材１３５とレチクルＲの間にゴミが入り込んでも、シール用部材１３５のレチクルＲのパターン面と直交する方向、すなわち厚さ方向の剛性が小さいため、ゴミかみによる反力はシール用部材１３５でかわすことができレチクルＲに変形を及ぼすことはない。さらに、シール用部材１３５の上面には金属の薄板１３５ａがあるため、レチクルＲが固着して交換時にレチクルＲをシール用部材１３５からはがすのが困難になることがないし、ゴムの成分（例えば可塑剤）がレチクルＲに付着することもない。 The vacuum suction unit 103 includes an outer frame 131, a plurality of internal pins 132, and a sealing member 135. By sucking air from the suction holes 134, the region 133 is evacuated to hold the reticle R by suction. The outer frame 131 and the inner pin 132 are made of a highly rigid material such as ceramic, and the sealing member 135 has a metal thin plate 135a bonded or bonded to the upper surface of a low elastic member 135b made of rubber. With such a configuration, the reticle R is brought into close contact with not only the outer frame 131 and the inner pin 132 but also the sealing member 135, so that the holding force by friction is increased. Accordingly, the width of the outer frame 131 can be reduced, and the probability that dust enters between the outer frame 131 and the reticle R is reduced. Further, even if dust enters between the sealing member 135 and the reticle R, the reaction force due to the dust bite is not effective for sealing because the rigidity in the direction perpendicular to the pattern surface of the reticle R of the sealing member 135, that is, the thickness direction is small. The member 135 can be dodged, and the reticle R is not deformed. Further, since there is a metal thin plate 135a on the upper surface of the sealing member 135, the reticle R is fixed and it is not difficult to peel off the reticle R from the sealing member 135 at the time of replacement. (Agent) does not adhere to the reticle R.

なお、シール用部材１３５の上面は外枠１３１および内部ピン１３２の上面より若干高くなっており、図２および図３に示すようにレチクルＲを吸着保持するとき最初にシール用部材１３５とレチクルＲが接触し、さらに吸引によってシール用部材１３５が厚さ方向に圧縮され外枠１３１および内部ピン１３２の上面にレチクルＲが接触し、安定した保持をすることができる。 Note that the upper surface of the sealing member 135 is slightly higher than the upper surfaces of the outer frame 131 and the inner pin 132. When the reticle R is sucked and held as shown in FIGS. Further, the sealing member 135 is compressed in the thickness direction by suction, and the reticle R comes into contact with the upper surfaces of the outer frame 131 and the inner pin 132, so that stable holding can be achieved.

本実施例では、シール用部材１３５の上面には金属の薄板１３５ａを接着あるいは接合しているが、テフロン（登録商標）コーティングや化学ニッケルメッキなどの表面処理によって薄膜を設けレチクルＲの固着およびゴムの成分の付着を防止してもよい。 In this embodiment, a thin metal plate 135a is bonded or bonded to the upper surface of the sealing member 135, but a thin film is provided by surface treatment such as Teflon (registered trademark) coating or chemical nickel plating, and the reticle R is fixed and rubber is bonded. The adhesion of these components may be prevented.

図４は本発明にかかわるレチクルチャックの第２実施例を示す拡大斜視図である。真空吸着部２０３は、複数の内部ピン２３２、内部ピン２３２を囲むように配置された複数の外枠ピン２３１およびシール用部材２３５で構成され、吸引穴からエアを吸引することによって、領域２３３を真空にしてレチクルＲを保持している。複数の外枠ピン２３１および内部ピン２３２はセラミックのような高剛性材料からなり、シール用部材２３５はゴムからなる低弾性部材２３５ｂの上面に金属の薄板２３５ａが接着あるいは接合されている。複数の外枠ピン２３１は、第１実施例における外枠１３１のようにレチクルＲとの接触面が連続した面ではなく離散的な面になっており、レチクルＲを吸引保持するための摩擦力が確保できれば、外枠ピン２３１とレチクルＲの間にゴミが入り込む確率がさらに低くなる。そして、第１実施例と同様に、シール用部材２３５とレチクルＲの間にゴミが入り込んでも、シール用部材２３５の厚さ方向の剛性が小さいため、レチクルＲに変形を及ぼすことはなく、シール用部材２３５の上面には金属の薄板２３５ａがあるため、レチクルＲがシール用部材２３５に固着して交換時にレチクルＲをはがすのが困難になることがないし、ゴムの成分（例えば可塑剤）がレチクルＲに付着することもない。 FIG. 4 is an enlarged perspective view showing a second embodiment of the reticle chuck according to the present invention. The vacuum suction unit 203 includes a plurality of inner pins 232, a plurality of outer frame pins 231 arranged so as to surround the inner pins 232, and a sealing member 235. By sucking air from the suction holes, the region 233 is formed. The reticle R is held in a vacuum. The plurality of outer frame pins 231 and inner pins 232 are made of a highly rigid material such as ceramic, and the sealing member 235 has a metal thin plate 235a bonded or bonded to the upper surface of a low elastic member 235b made of rubber. The plurality of outer frame pins 231 are discrete surfaces instead of a continuous surface with the reticle R like the outer frame 131 in the first embodiment, and a frictional force for sucking and holding the reticle R is provided. Can be ensured, the probability of dust entering between the outer frame pin 231 and the reticle R is further reduced. As in the first embodiment, even when dust enters between the sealing member 235 and the reticle R, the rigidity of the sealing member 235 in the thickness direction is small. Since there is a metal thin plate 235a on the upper surface of the member 235, the reticle R is not fixed to the sealing member 235 and it is difficult to remove the reticle R at the time of replacement. It does not adhere to the reticle R.

なお、シール用部材２３５の上面は外枠ピン２３１および内部ピン２３２の上面より若干高くなっており、レチクルＲを吸着保持するとき最初にシール用部材２３５とレチクルＲが接触し、さらに吸引によってシール用部材２３５が厚さ方向に圧縮され外枠ピン２３１および内部ピン２３２の上面にレチクルＲが接触し、安定した保持をすることができる。 Note that the upper surface of the sealing member 235 is slightly higher than the upper surfaces of the outer frame pin 231 and the inner pin 232, and when the reticle R is sucked and held, the sealing member 235 and the reticle R first come into contact with each other, and are further sealed by suction. The member 235 is compressed in the thickness direction, and the reticle R comes into contact with the upper surfaces of the outer frame pin 231 and the inner pin 232, so that stable holding can be achieved.

本実施例では、シール用部材２３５の上面には金属の薄板２３５ａを接合しているが、テフロン（登録商標）コーティングや化学ニッケルメッキなどの表面処理によって薄膜を設けレチクルＲの固着およびゴムの成分の付着を防止してもよい。 In this embodiment, a metal thin plate 235a is bonded to the upper surface of the sealing member 235. However, a thin film is provided by surface treatment such as Teflon (registered trademark) coating or chemical nickel plating, and the adhesion of the reticle R and the rubber component May be prevented.

図５は本発明にかかわるレチクルチャックの第３実施例を示す拡大断面図である。真空吸着部３０３は、外枠３３１、内部ピン３３２およびシール用部材３３５で構成され、吸引穴３３４からエアを吸引することによって、領域３３３を真空にしてレチクルＲを保持している。外枠３３１および内部ピン３３２は第１実施例と同様セラミックのような高剛性材料からなり、シール用部材３３５は金属からなりベローズ状の形状にすることによってレチクルＲのパターン面と直交する方向にバネ性を持たせている。このようにすることによって、シール用部材３３５とレチクルＲの間にゴミが入り込んでも、シール用部材３３５の厚さ方向の剛性が小さいため、レチクルＲに変形を及ぼすことはない。また、シール用部材３３５は金属からなるため、レチクルＲがシール用部材３３５に固着して交換時にレチクルＲをはがすのが困難になることがないし、ゴムの成分（例えば可塑剤）がレチクルＲに付着することもない。 FIG. 5 is an enlarged sectional view showing a third embodiment of the reticle chuck according to the present invention. The vacuum suction unit 303 includes an outer frame 331, an internal pin 332, and a sealing member 335, and sucks air from the suction hole 334 to evacuate the region 333 and hold the reticle R. The outer frame 331 and the inner pin 332 are made of a high-rigidity material such as ceramic as in the first embodiment, and the sealing member 335 is made of metal and has a bellows shape in a direction perpendicular to the pattern surface of the reticle R. Has springiness. By doing so, even if dust enters between the sealing member 335 and the reticle R, the rigidity in the thickness direction of the sealing member 335 is small, so that the reticle R is not deformed. Further, since the sealing member 335 is made of metal, the reticle R is fixed to the sealing member 335 so that it is not difficult to peel off the reticle R during replacement, and a rubber component (for example, a plasticizer) is not attached to the reticle R. There is no adhesion.

なお、シール用部材３３５の上面は外枠３３１および内部ピン３３２の上面より若干高くなっており、レチクルＲを吸着保持するとき最初にシール用部材３３５とレチクルＲが接触し、さらに吸引によってシール用部材３３５が厚さ方向に変形し外枠３３１および内部ピン３３２の上面にレチクルＲが接触し、安定した保持をすることができる。 Note that the upper surface of the sealing member 335 is slightly higher than the upper surfaces of the outer frame 331 and the inner pin 332, and when the reticle R is sucked and held, the sealing member 335 and the reticle R first come into contact with each other, and further, the sealing member is sealed by suction. The member 335 is deformed in the thickness direction, and the reticle R comes into contact with the upper surfaces of the outer frame 331 and the inner pin 332, so that stable holding can be achieved.

なお、保持部の周囲にシール用部材を設けたレチクルチャックの先行例として、例えば特開昭６２−１００７５３号に開示されたものがあるが、この場合はレチクルと保持部の接触を面から多点にしてゴミかみを防ぐものであり、シール用部材の構成に関する記述はなく本発明とは異なるものである。 As a prior example of a reticle chuck in which a sealing member is provided around the holding portion, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 62-1000075. In this case, the contact between the reticle and the holding portion is increased from the surface. In this respect, dust bites are prevented, and there is no description regarding the configuration of the sealing member, which is different from the present invention.

本発明における第１実施例である半導体露光装置に適用されるレチクルチャックの拡大斜視図。1 is an enlarged perspective view of a reticle chuck applied to a semiconductor exposure apparatus that is a first embodiment of the present invention. FIG. 本発明における第１実施例である半導体露光装置に適用されるレチクルチャックの拡大断面図。1 is an enlarged cross-sectional view of a reticle chuck applied to a semiconductor exposure apparatus that is a first embodiment of the present invention. 本発明における第１実施例である半導体露光装置に適用されるレチクルチャックのレチクル吸引時の拡大断面図。FIG. 3 is an enlarged cross-sectional view of a reticle chuck applied to the semiconductor exposure apparatus according to the first embodiment of the present invention during reticle suction. 本発明における第２実施例である半導体露光装置に適用されるレチクルチャックの拡大斜視図。The expansion perspective view of the reticle chuck applied to the semiconductor exposure apparatus which is 2nd Example in this invention. 本発明における第３実施例である半導体露光装置に適用されるレチクルチャックの拡大断面図。The expanded sectional view of the reticle chuck applied to the semiconductor exposure apparatus which is 3rd Example in this invention. 従来例におけるレチクルの保持機構を示す概略斜視図。FIG. 10 is a schematic perspective view showing a reticle holding mechanism in a conventional example. 従来例におけるレチクルチャックの拡大斜視図。The enlarged perspective view of the reticle chuck in a prior art example. 従来例におけるレチクルチャックの拡大平面図。The enlarged plan view of the reticle chuck in a prior art example. 従来例におけるレチクルチャックの拡大断面図。The expanded sectional view of the reticle chuck in a prior art example. 従来例におけるレチクルチャックで、内部ピンがない場合のレチクル吸引時の拡大断面図。The expanded sectional view at the time of reticle suction in the case of the reticle chuck in the conventional example when there is no internal pin. 従来例におけるレチクルチャックで、ゴミをかんだ場合のレチクル吸引時の拡大断面図。The expanded sectional view at the time of reticle attraction | suction at the time of biting dust with the reticle chuck in a prior art example.

Explanation of symbols

１レチクル天板
２レチクルチャックベース
３，１０３，２０３，３０３真空吸着部
３１，１３１，３３１外枠
２３１外枠ピン
３２，１３２，２３２，３３２内部ピン
３３，１３３，２３３，３３３真空領域
３４，１３４，３３４吸引穴
１３５，２３５，３３５シール用部材
１３５ａ，２３５ａ金属薄板
１３５ｂ，２３５ｂゴム
Ｒ，Ｒ’ レチクル DESCRIPTION OF SYMBOLS 1 Reticle top plate 2 Reticle chuck base 3,103,203,303 Vacuum adsorption part 31,131,331 Outer frame 231 Outer frame pin 32,132,232,332 Internal pin 33,133,233,333 Vacuum area 34,134 , 334 Suction hole 135, 235, 335 Sealing member 135 a, 235 a Metal thin plate 135 b, 235 b Rubber R, R ′ reticle

Claims

A first holding unit that holds the posture of the reticle, a second holding unit that is arranged around the first holding unit, and a direction perpendicular to the pattern surface of the reticle around the second holding unit. A reticle chuck provided with a spring elastic sealing member, wherein the upper surface of the sealing elastic member contacting the back surface of the reticle is made of a material having low adhesion.

2. The reticle chuck according to claim 1, wherein the sealing elastic member is made of a low elastic material such as rubber, and a thin plate with low adhesion is integrally provided on an upper surface in contact with the reticle back surface.

2. The reticle chuck according to claim 1, wherein the sealing elastic member is made of a low-elasticity material such as rubber, and the upper surface in contact with the back surface of the reticle is reduced in adhesion by coating or plating.

2. The reticle chuck according to claim 1, wherein the elastic member for sealing is made of metal and has a shape having a spring property.

5. The reticle chuck according to claim 1, wherein an inner side of the sealing elastic member is a negative pressure region due to Vac suction.

6. The reticle chuck according to claim 1, wherein an upper surface of the sealing elastic member is higher than upper surfaces of the first holding part and the second holding part.

The reticle chuck according to claim 1, wherein the first holding portion includes a plurality of pins.

The reticle chuck according to claim 1, wherein the second holding portion includes a plurality of pins.

The reticle chuck according to claim 1, wherein the second holding portion is a ring-shaped outer frame.