JP2008226973A - Exposure system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure system which eliminates a need of separately operating a scanning direction masking member in response to scanning operation by a reticle stage, and, at the same time, can remove particles sticking to the reticle or a chuck member. <P>SOLUTION: The exposure system synchronously scans the reticle stage on which the reticle is disposed and a sensitive board stage on which a sensitive board is disposed to transfer a pattern formed on the surface of the reticle to the sensitive board. The reticle stage includes a moving table which moves in a scanning direction, the chuck member which is disposed on the moving table with the chuck member suction surface set downward to suck up the reticle, the scanning direction masking member which is disposed on the moving table to limit an exposure area in the scanning direction of the reticle, and a moving means which is disposed on the moving table to move the scanning direction masking member in movement accompanying vibrations. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exposure apparatus used for lithography such as a semiconductor integrated circuit.

In an EUV exposure apparatus that uses EUV light as exposure light, the reticle stage on which the reticle is placed and the wafer stage on which the wafer is placed are scanned in synchronization, and the reticle pattern of the exposure light reflected by the reticle is placed on the wafer. Transfer exposure is performed.
Then, various exposure areas can be set by moving a light shielding member called a reticle blind to a predetermined position. In the EUV exposure apparatus, as a light shielding member, a fixed blind that defines an exposure area of exposure light, a scanning direction light shielding member that restricts an exposure area in the scanning direction of the reticle, and a non-scanning direction light shielding that restricts an exposure area in the non-scanning direction of the reticle. A member is disposed between the reticle and the projection optical system.
JP-A-6-232031

However, the conventional EUV exposure apparatus has a problem that a scanning direction light-shielding member for limiting the exposure area in the scanning direction of the reticle is required to be separately driven in accordance with the scanning operation of the reticle stage.
Further, the reticle stage is provided with a chuck member that attracts the reticle, but it is desired to effectively remove particles adhering to the reticle or chuck member.

  The present invention has been made to solve such a conventional problem, and eliminates the need to separately operate the scanning direction light shielding member in response to the scanning operation of the reticle stage, and at the same time, removes particles adhering to the reticle or chuck member. An object of the present invention is to provide an exposure apparatus that can be removed.

  In the exposure apparatus of the first invention, a reticle stage on which a reticle is arranged and a sensitive substrate stage on which a sensitive substrate is arranged are scanned synchronously, and a pattern formed on the surface of the reticle is formed on the sensitive substrate. In the exposure apparatus for transferring, the reticle stage includes a moving table that moves in a scanning direction, a chuck member that is arranged on the moving table with an adsorption surface downward, and that adsorbs the reticle, and is arranged on the moving table. A scanning direction light shielding member that limits an exposure area in the scanning direction, and a moving unit that is arranged on the moving table and moves the scanning direction light shielding member with vibration.

An exposure apparatus according to a second invention is the exposure apparatus according to the first invention, wherein the moving means has an ultrasonic linear actuator.
An exposure apparatus according to a third aspect is characterized in that, in the exposure apparatus according to the first or second aspect, the moving table is a fine movement table arranged so as to be finely movable on a coarse movement table moving in a scanning direction. .

An exposure apparatus according to a fourth aspect is the exposure apparatus according to any one of the first to third aspects, wherein the chuck member is an electrostatic chuck.
An exposure apparatus according to a fifth invention is the exposure apparatus according to any one of the first to fourth inventions, wherein the moving means moves the end of the scanning direction light shielding member outside the reticle pattern surface during exposure. It is located below the non-pattern part.

An exposure apparatus of a sixth invention is characterized in that, in the exposure apparatus of the fifth invention, the moving means positions the end portions of the pair of scanning direction light shielding members at the non-pattern portions on both sides of the reticle. To do.
An exposure apparatus according to a seventh aspect is the exposure apparatus according to any one of the first to sixth aspects, wherein a non-scanning direction light shielding member that limits an exposure area in the non-scanning direction of the reticle, and an exposure area of the exposure light And a fixed blind that defines

  An exposure apparatus according to an eighth aspect is characterized in that, in the exposure apparatus according to the seventh aspect, the scanning direction light shielding member, the fixed blind, and the non-scanning direction light shielding member are sequentially arranged from the side closer to the reticle. And

  In the exposure apparatus of the present invention, it is not necessary to separately operate the scanning direction light shielding member in response to the scanning operation of the reticle stage, and at the same time, particles adhering to the reticle or chuck member can be removed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an embodiment of the exposure apparatus of the present invention.
The exposure apparatus includes a light source unit 11, an illumination optical system 13, a reticle stage 15, a projection optical system 17, and a wafer stage 19.
The light source unit 11 converts the target material into plasma and generates pulsed light composed of EUV light.

In the light source unit 11, a gas or liquid target material is intermittently ejected from the tip of the nozzle 21 into the light emitting unit 23. The laser light 27 emitted from the laser device 25 is condensed on the target material via the lens 29, and the target material is turned into plasma. Thereby, EUV light 31 composed of pulsed light is generated.
The illumination optical system 13 guides illumination light to the lower surface of the reticle 33 arranged below the reticle stage 15.

  In the illumination optical system 13, the EUV light 31 from the light source unit 11 becomes a substantially parallel light beam via the concave reflecting mirror 35 that acts as a collimator mirror, and includes a first fly-eye mirror 37 and a second fly-eye mirror 39. The light enters the optical integrator 41. Thereby, a substantial surface light source having a predetermined shape (in this example, an arc shape but not limited to this shape) is formed in the vicinity of the reflection surface of the second fly-eye mirror 39. The EUV light 31 from the substantial surface light source is reflected by the reflecting mirrors 43 and 45 and then deflected by the planar reflecting mirror 47.

The reticle stage 15 has a coarse movement table 48 and a fine movement table 49. The coarse movement table 48 is movable in the X, Y, and Z directions, and moves the reticle 33 in the scanning direction via the fine movement table 49. The fine movement table 49 is arranged on the coarse movement table 48 so as to be finely movable.
An electrostatic chuck 51 is fixed below the fine movement table 49, and a reticle 33 is held by suction on the lower surface of the electrostatic chuck 51. Below the reticle 33, scanning direction light shielding members 53 and 54, a fixed blind 55, and a non-scanning direction light shielding member 57 are arranged. Details of the light shielding members 53, 54, 55, and 57 will be described later.

  The EUV light 31 deflected by the plane reflecting mirror 47 passes through the openings of the non-scanning direction light shielding member 57, the fixed blind 55 and the scanning direction light shielding members 53, 54, and forms an elongated arc-shaped illumination region on the lower surface of the reticle 33. To do. For convenience of explanation, the non-scanning direction light blocking member 57, the fixed blind 55, and the scanning direction light blocking members 53 and 54 block the illumination light incident on the reticle 33, but block the light beam reflected from the reticle 33. It is also good. Further, the light beam may be shielded on both the incident side and the reflection side. In other words, it may be arranged so that the shape of the exposure area on the wafer can be finally defined.

The reticle 33 has a multilayer film that reflects the EUV light 31 and an absorber pattern layer for forming a pattern. The EUV light 31 is patterned by reflecting the EUV light 31 with the reticle 33.
The projection optical system 17 has four reflecting mirrors, and each of the mirrors 17 a to 17 d is provided with a multilayer film that reflects the EUV light 31. The EUV light 31 reflected and patterned by the reticle 33 is sequentially reflected from the first mirror 17 a to the fourth mirror 17 d to form a reduced image of the reticle pattern on the wafer 61.

  The wafer stage 19 is movable in the X, Y, and Z directions. An electrostatic chuck 59 is fixed on the upper side of the wafer stage 19, and the wafer 61 is attracted and held on the upper surface of the electrostatic chuck 59. When exposing the die on the wafer 61, the EUV light 31 is irradiated onto a predetermined area of the reticle 33, and the reticle 33 and the wafer 61 are at a predetermined speed according to the reduction ratio of the projection optical system 17 with respect to the projection optical system 17. It moves with. In this way, the pattern of the reticle 33 is exposed to a predetermined exposure range (with respect to the die) on the wafer 61.

2 and 3 show details of the reticle stage 15.
In FIG. 2, a fine movement table 49 is disposed below the coarse movement table 48. The fine movement table 49 is held below the coarse movement table 48 via an attitude control actuator 62 and can be finely moved by the attitude control actuator 62.
An electrostatic chuck 51 is fixed below the fine movement table 49. The reticle 33 is held by suction on the suction surface 51 a on the lower surface of the electrostatic chuck 51. Below the reticle 33, the projection optical system 17 is disposed, and between the reticle 33 and the projection optical system 17, the scanning direction light shielding members 53 and 54, the fixed blind 55, and the non-scanning direction light shielding member 57 are sequentially disposed. . By disposing the scanning direction light shielding members 53 and 54 in the vicinity of the reticle 33, the light shielding accuracy by the scanning direction light shielding members 53 and 54 can be improved.

  The scanning direction light shielding members 53 and 54 are movable in the scanning direction (Y direction) of the fine movement table 49 along the guide member 63 disposed on the fine movement table 49. As shown in FIG. 3, a pair of guide members 63 are disposed on the lower surface of fine movement table 49 at positions on both sides of reticle 33 (electrostatic chuck 51). The pair of guide members 63 extend in the scanning direction (Y direction) of the fine movement table 49. Further, the scanning direction light shielding members 53 and 54 are disposed on the pair of guide members 63. The scanning direction light shielding members 53 and 54 are disposed across a pair of guide members 63, and both ends thereof are guided by the guide members 63. The guide member 63 is provided with a moving mechanism 65 (not shown in FIGS. 2 and 3) for moving the scanning direction light shielding members 53 and 54 in the scanning direction.

  As shown in FIG. 4, the moving mechanism 65 includes an ultrasonic linear actuator 67 and a linear guide 69. The guide member 63 is formed with a rectangular recess 63a. An ultrasonic linear actuator 67 and a linear guide 69 are disposed in the recess 63a with the end portions of the scanning direction light shielding members 53 and 54 interposed therebetween. The linear guide 69 guides the end portions of the scanning direction light shielding members 53 and 54. The ultrasonic linear actuator 67 moves the light blocking members 53 and 54 in the scanning direction by driving a piezoelectric element (not shown). As a result of the driving of the piezoelectric element, a relatively large vibration is generated in the guide member 63 as compared with the case where a linear motor is used. The ultrasonic linear actuator 67 is well known and will not be described in detail. In addition, the guide member 63 is divided at the center in the scanning direction to prevent vibration interference of the pair of ultrasonic linear actuators 67 arranged on both sides of the guide member 63, but the illustration is omitted.

The positions of the scanning direction light blocking members 53 and 54 on the linear guide 69 can be measured by a linear encoder (not shown). When the reticle 33 is replaced or when the fiducial mark is autofocused, the scanning direction light shielding members 53 and 54 are positioned outside the reticle 33 in the scanning direction, as shown in FIG.
In FIG. 3, a symbol S indicates an arcuate illumination area irradiated on the pattern surface 33 a of the reticle 33. The direction of the straight line passing through the center of the arcuate illumination area S in the radial direction is the scanning direction of the reticle 33. A pair of scanning direction light shielding members 53 and 54 that limit the scanning direction of the reticle 33 are disposed at positions on both sides of the illumination region S in the scanning direction. The scanning direction light shielding members 53 and 54 prevent the exposure area from protruding before and after scanning, and are sometimes called mask blinds or synchronous blinds. Note that a non-pattern portion 33 b is formed outside the pattern surface 33 a of the reticle 33 so as to surround the pattern surface 33 a and no pattern is formed.

  At the time of exposure, as shown in FIGS. 5 and 6, the inner ends of the scanning direction light shielding members 53 and 54 are positioned at the boundary between the pattern surface 33 a of the reticle 33 and the non-pattern portion 33 b. This state is maintained during exposure, and the scanning direction light blocking members 53 and 54 are not moved. At the start of the exposure operation, as shown in FIG. 5A, the scanning direction light blocking member 54 is located at a position covering the illumination area S, and the exposure area of the reticle 33 in the scanning direction is limited. At the end of the exposure operation, as shown in FIG. 5B, the scanning direction light shielding member 53 is located at a position covering the illumination area S, and the exposure area of the reticle 33 in the scanning direction is limited. This prevents unnecessary illumination light from being applied to the wafer 61.

As shown in FIG. 3, the non-scanning direction light blocking members 57 are arranged on both sides of the arcuate illumination area S in the direction perpendicular to the scanning direction. The non-scanning direction light blocking member 57 determines the scanning width by limiting the non-scanning direction of the illumination area S. The non-scanning direction light shielding member 57 can be moved in a direction perpendicular to the scanning direction by a driving device (not shown).
The fixed blind 55 defines the shape of the arcuate illumination area S that is irradiated onto the reticle 33. The fixed blind 55 is a slit for determining the projection area of the projection optical system 17, and defines the maximum exposure area in the case of still exposure in which the reticle stage 15 is not scanned. Since the fixed blind 55 is desirably installed close to the pattern surface 33a of the reticle 33 in terms of optical design, it is installed close to the lower side of the scanning direction light shielding members 53 and 54 as shown in FIG.

  In the exposure apparatus described above, since the scanning direction light shielding members 53 and 54 are provided on the fine movement table 49 of the reticle stage 15, the scanning direction light shielding members 53 and 54 move together with the fine movement table 49. Therefore, it is not necessary to separately operate the scanning direction light shielding members 53 and 54 in response to the scanning operation of the reticle stage 15 at the start and end of the exposure operation, and the synchronous operation of the reticle stage 15 and the scanning direction light shielding members 53 and 54 is performed. Control can be dispensed with.

  Further, in the above-described exposure apparatus, since the scanning direction light blocking members 53 and 54 are moved by the moving mechanism 65 including the ultrasonic linear actuator 67, particles adhering to the reticle 33 or the electrostatic chuck 51 are effectively removed. Can be removed. That is, when the ultrasonic linear actuator 67 is used for the moving mechanism 65, a relatively large vibration is generated in the guide member 63 as compared with the case where a linear motor is used, and this vibration is transmitted to the electrostatic chuck 51. The electrostatic chuck 51 vibrates.

  Therefore, when exchanging the reticle 33, before attaching the reticle 33 to the electrostatic chuck 51, the moving mechanism 65 is operated for a predetermined time to reciprocate the scanning direction light shielding members 53, 54, thereby attracting the electrostatic chuck 51. Particles attached to the surface 51a can be dropped by gravity to remove the particles from the adsorption surface 51a. As a result, when the reticle 33 is attracted to the electrostatic chuck 51, the presence of particles between the electrostatic chuck 51 and the reticle 33 is reduced, and the mounting accuracy of the reticle 33 can be improved.

  In addition, after the reticle 33 is attached to the electrostatic chuck 51, the moving mechanism 65 is operated for a predetermined time to reciprocate the scanning direction light shielding members 53 and 54, so that the particles adhering to the pattern surface 33a of the reticle 33 are gravitated. The particles can be removed from the pattern surface 33a. Thereby, the presence of particles on the pattern surface 33a is reduced, and the exposure accuracy can be improved.

Further, in the exposure apparatus described above, as shown in FIGS. 5 and 6, the inner ends of the scanning direction light shielding members 53 and 54 are positioned below the boundary between the pattern surface 33a of the reticle 33 and the non-pattern portion 33b as shown in FIGS. Therefore, it is possible to prevent the reticle 33 from being damaged when it is accidentally dropped. That is, at the time of exposure, when the reticle 33 is accidentally dropped because the power supply of the electrostatic chuck 51 is turned off due to a malfunction or the like, the reticle 33 is placed on the scanning direction light shielding members 53 and 54 to prevent the reticle 33 from being damaged. Is done.
(Supplementary items of the embodiment)
As mentioned above, although this invention was demonstrated by embodiment mentioned above, the technical scope of this invention is not limited to embodiment mentioned above, For example, the following forms may be sufficient.

(1) In the above-described embodiment, an example in which the scanning direction light shielding members 53 and 54 are moved by the moving mechanism 65 including the ultrasonic linear actuator 67 has been described. However, vibration is generated when the scanning direction light shielding member is moved. Any moving mechanism may be used.
(2) In the above-described embodiment, the example in which the electrostatic chuck 51 is used as the chuck member has been described. However, any chuck member that can attract the reticle may be used.

  (3) In the above-described embodiment, the example in which the present invention is applied to the reticle stage 15 including the coarse movement table 48 and the fine movement table 49 and the electrostatic chuck 33 is arranged on the fine movement table 49 has been described. It can also be applied to a reticle stage that does not exist. In this case, an electrostatic chuck, a scanning direction light shielding member, and a moving mechanism are arranged on a table corresponding to the coarse movement table.

(4) In the above-described embodiment, the example in which the laser-generated plasma light source is used as the light source of the EUV light 31 has been described. For example, the target material is intermittently supplied between the electrodes, and discharge is performed in accordance with the target material. It may be a discharge plasma X-ray source that generates light.
(5) In the above-described embodiment, an example in which the present invention is applied to an EUV light exposure apparatus has been described. However, the present invention can be widely applied to an exposure apparatus that exposes a sensitive substrate with exposure light reflected by a reticle. .

It is explanatory drawing which shows one Embodiment of the exposure apparatus of this invention. FIG. 2 is an explanatory diagram showing details of the reticle stage of FIG. 1. FIG. 3 is an explanatory view showing a state when the reticle stage of FIG. 2 is viewed from below. It is explanatory drawing which shows the moving mechanism of a scanning direction light shielding member. It is explanatory drawing which shows the position at the time of exposure of the scanning direction light-shielding member from the lower side. It is explanatory drawing which shows the position at the time of exposure of the scanning direction light shielding member from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 15 ... Reticle stage, 19 ... Wafer stage, 33 ... Reticle, 33a ... Pattern surface, 33b ... Non-pattern part, 48 ... Coarse movement table, 49 ... Fine movement table, 51 ... Electrostatic chuck, 53, 54 ... Scanning direction light shielding member , 55 ... fixed blind, 57 ... non-scanning direction light shielding member, 61 ... wafer, 63 ... guide member, 65 ... moving mechanism, 67 ... ultrasonic linear actuator.

Claims (8)

In an exposure apparatus that synchronously scans a reticle stage on which a reticle is arranged and a sensitive substrate stage on which a sensitive substrate is arranged, and transfers a pattern formed on the surface of the reticle onto the sensitive substrate.
The reticle stage is
A moving table that moves in the scanning direction;
A chuck member that is disposed on the moving table with the suction surface facing downward and sucks the reticle;
A scanning direction light-shielding member that is disposed on the moving table and limits an exposure area in the scanning direction of the reticle;
Moving means arranged on the moving table to move the scanning direction light blocking member with vibration;
An exposure apparatus comprising: The exposure apparatus according to claim 1, wherein
The exposure apparatus according to claim 1, wherein the moving means includes an ultrasonic linear actuator. The exposure apparatus according to claim 1 or 2,
The exposure apparatus according to claim 1, wherein the movement table is a fine movement table that is arranged to be finely movable on a coarse movement table that moves in a scanning direction. The exposure apparatus according to any one of claims 1 to 3,
The exposure apparatus, wherein the chuck member is an electrostatic chuck. The exposure apparatus according to any one of claims 1 to 4,
The exposure apparatus is characterized in that the moving means positions an end portion of the scanning direction light shielding member below a non-pattern portion outside the pattern surface of the reticle during exposure. The exposure apparatus according to claim 5, wherein
The exposure apparatus is characterized in that the moving means positions end portions of the pair of scanning direction light shielding members on the non-pattern portions on both sides of the reticle. The exposure apparatus according to any one of claims 1 to 6,
A non-scanning direction light blocking member for limiting an exposure area of the reticle in the non-scanning direction;
A fixed blind that defines an exposure area of the exposure light;
An exposure apparatus comprising: The exposure apparatus according to claim 7, wherein
The exposure apparatus, wherein the scanning direction light shielding member, the fixed blind, and the non-scanning direction light shielding member are arranged in order from the side close to the reticle.

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