JPH08115868A - Cleaning device for aligner - Google Patents

Abstract

PURPOSE: To automatically and easily eliminate various kinds of foreign objects on a wafer holder. CONSTITUTION: While organic material abrasion materials 32A-32C of a scrub unit 21 and high-hardness abrasion materials 33A-33C are pressed against a wafer holder 9 by a rotary arm 20A, gears 27A, 27B, and 27C are rotated in planetary gear system by a drive motor 26 and drive rollers 28A, 28B,... interlocked to the gears are rotated, thus sliding the abrasion materials on a wafer holder 9. The press force of the abrasion material is adjusted based on the press force detected by a pressure sensor 31 and at the same time a foreign object dropped by abrasion is unloaded to the outside via an exhaust duct 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in a projection exposure apparatus used for manufacturing a semiconductor device, a liquid crystal display device, etc. by using a photolithography technique, and a wafer holder for holding a photosensitive substrate. The present invention relates to a cleaning device for an exposure device, which is suitable for being applied to a device for cleaning the surface of a substrate holding member.

[0002]

2. Description of the Related Art A projection exposure apparatus for exposing a pattern image of a reticle (or photomask, etc.) onto a wafer on a wafer stage via a projection optical system when manufacturing a semiconductor device, a liquid crystal display device or the like by a photolithography process. Is used. In such a conventional projection exposure apparatus, in order to hold the wafer in a flat state so as not to move, a wafer holder attached on a wafer stage sucks and holds the wafer.

However, if a wafer is attracted in the presence of foreign matter such as dust or dirt between the wafer holder holding the wafer and the wafer, the foreign matter deteriorates the flatness of the exposed surface of the wafer. The deterioration of the degree of change in the exposed surface is
This has been a cause of positional deviation error and focus error of each shot area of the wafer, and has been a major factor of deteriorating the yield in manufacturing LSIs and the like. Therefore, conventionally, the exposure process is generally stopped at regular intervals, the wafer holder is moved to a position where the operator can reach, and the operator moves the wafer holder with a grindstone or a dust-free cloth to wipe the entire wafer holder. It was

On the other hand, in order to make the cleaning work more efficient, the applicant of the present invention has disclosed that in Japanese Patent Application Nos. 4-230069 and 5-216570, a wafer holder is automatically mounted using a cleaning member such as a grindstone. Cleaning technology and wafer focus position (position in the optical axis direction of the projection optical system)
Using the focus position detection means to detect the, the technology to determine the presence of foreign matter by comparing the focus position of the previous shot area and the focus position of the current shot area, and the detection result of the focus position detection means Has been proposed to find a region requiring cleaning on the surface of the wafer holder, and the technique for focusing on the region requiring cleaning is proposed.

[0005]

However, since the minute foreign matter on the surface of the wafer holder is firmly attached by various kinds of van der Waals force, chemical bonding force, binding force by static electricity, etc. However, there is an inconvenience that it is difficult to remove it sufficiently even if the technique is used. This is because even if the wafer holder is wiped off with a dust-free cloth or a grindstone, the resist and dust that have been peeled off once again adhere to other areas and remain on the wafer holder. In addition, once peeled resist and dust enter the vacuum suction groove and vacuum suction hole on the wafer holder,
At the timing of vacuum-off (release of adsorption) of the wafer holder, those resists and the like may be blown again onto the surface of the wafer holder to cause recontamination. It was difficult to completely remove the resist and dust in such a state by the conventional technique.

Furthermore, since the surface of the wafer holder is not hydrophilic due to the influence of various photoresists, it is difficult to remove the resist by peeling it off with a dust-free cloth or the like. Therefore, since the abrasive material such as a grindstone is frequently used for cleaning automatically or manually, the abrasive material may damage the surface of the wafer holder itself.

Further, the wafer holder is usually provided with a wafer transfer portion (a vertically moving pin or the like), but the photoresist and dust adhering to the wafer transfer portion cause a problem of strength of the transfer portion, a difference in position, and the like. Since it could not be removed due to the above problem, the residual resist and dust adhering to the transfer part sometimes move to the wafer holder when the wafer is transferred. Therefore, there are cases in which a good result may not be obtained even if the wafer holder is cleaned many times, and further, the residual resist and the like may contaminate not only the wafer holder but also the peripheral devices (stage, etc.). It was

In view of the above problems, an object of the present invention is to provide a cleaning device for an exposure apparatus which can automatically and easily remove various foreign substances attached to the surface of a wafer holder (substrate holding member). A further object of the present invention is to provide a cleaning device for an exposure apparatus, which can easily remove various foreign substances, and in which the foreign substances once peeled do not adhere to and remain on other regions of the wafer holder again. .

Another object of the present invention is to provide a cleaning device for an exposure apparatus which can remove foreign matter on the surface of a wafer holder without damaging the surface of the wafer holder even if the surface of the wafer holder is not hydrophilic. .

[0010]

A cleaning device for a first exposure apparatus according to the present invention is, for example, as shown in FIGS. 1 and 2, a photosensitive member having a mask pattern held on a substrate holding member (9). Of the exposure apparatus for exposing the substrate (10) of the above, and for cleaning the surface of the substrate holding member, a solid first cleaning member (33B) and a second cleaning containing an organic material. The member (32B), the pressing means (18, 19) for contacting and biasing the first and second cleaning members with the surface of the substrate holding member (9), and the first and second cleaning members. Drive means (26, 27A) for moving the substrate holding member (9) on the surface of the substrate holding member (9), and pressure contact force detecting means (31) for detecting the pressure contact force applied to the surface of the substrate holding member (9) by the pressurizing means. The pressure contact force detected by this pressure contact force detection means A pressing force control means (43) for controlling the pressing force applied from the pressurizing means (18, 19) on the substrate holding member (9) Zui, and has a.

In this case, it is desirable to provide exhaust means (25) for sucking and exhausting gas in the vicinity of the substrate holding member (9). The second cleaning apparatus for the exposure apparatus of the present invention, as shown in FIGS. 1 and 3, for example, has a mask pattern on a photosensitive substrate (10) held on a substrate holding member (9). A light source (56A) for irradiating the surface of the substrate holding member (9) with ultraviolet rays in an apparatus for cleaning the surface of the substrate holding member provided in an exposure device for exposing.
A shielding member (24B, 36B) that substantially shields the space from the surface of the substrate holding member (9) to the light source (56A) and the space outside thereof, and the substrate holding member covered with this shielding member ( The exhaust means (52) for sucking and exhausting gas near the surface of (9).

In this case, the illuminance detecting means (53) for detecting the illuminance of the ultraviolet rays emitted from the light source (56A), and the light source (5) based on the illuminance detected by the illuminance detecting means.
6A) light source control means (44) for controlling the light emission intensity,
Is desirable. Further, a temperature detecting means (46) for detecting the temperature of the substrate holding member (9) and a cooling means (42) for cooling the substrate holding member (9) based on the detection result of the temperature detecting means are provided. Is desirable.

Further, as shown in FIGS. 1 to 3, the cleaning device for the third exposure apparatus of the present invention has a photosensitive substrate (10) holding a mask pattern on the substrate holding member (9). ) An apparatus for cleaning the surface of a substrate holding member provided in an exposure apparatus for exposing the above, a solid first cleaning member (33B) and a second cleaning member (32B) containing an organic material. A driving means (21) for moving the substrate holding member (9) in contact with the surface thereof, a light source (56A) for irradiating the surface of the substrate holding member (9) with ultraviolet rays, and a surface of the substrate holding member (9). A shield member (24B, 3) that substantially shields the space up to the light source and the space outside thereof.
6B) and a substrate holding member (9) covered with this shielding member
Irradiation evacuation means (22) having evacuation means (52) for sucking and exhausting gas in the vicinity of the surface, driving means (21),
Switching means (18, 19, 20A, 2) for alternately mounting the irradiation evacuation means (22) on the surface of the substrate holding member (9).
0B), and.

[0014]

According to the cleaning apparatus for the first exposure apparatus of the present invention, a solid first cleaning member such as a grindstone,
A second cleaning member containing an organic material such as a synthetic resin brush is slid at the same time while being pressed against the surface of the substrate holding member (9). Moreover, since the pressure contact force can be controlled, by adjusting the pressure contact force according to the type and state of the foreign matter, various foreign matter such as resist and dust on the surface of the substrate holding member (9) can be automatically and Can be easily and almost completely removed. At this time, since the first and second cleaning member sides move while the substrate holding member (9) is stationary, the cleaning operation is safely performed.

Also, the gas in the vicinity of the substrate holding member (9)
If an exhaust means for sucking and exhausting is provided, hold the substrate
Fine foreign matter separated from the surface of the member (9) is
It is sucked by the exhaust means together with the body, and again the substrate holding member
It does not adhere to the surface of (9). Then a second exposure
According to the cleaning device for the apparatus, the substrate holding member
The surface of (9) is irradiated with ultraviolet light, and the ultraviolet light causes
Zon occurs. Therefore, the vacuum of the substrate holding member (9)
Peel resist or organic material that has entered the adsorption groove or vacuum adsorption hole, etc.
Material Small pieces such as abrasives interact with UV and ozone
Causes carbon dioxide (CO ₂) And water vapor (H₂O) and
It is decomposed and exhausted. Therefore, the substrate holding member (9)
On the surface of the substrate holding member (9) without fear of scratching the surface
To remove virtually all of the organic dust from
Is possible. Moreover, since a shielding member is provided,
Eliminates the risk of contaminating equipment around.

Further, when the substrate holding member (9) is provided with the substrate transfer section (40), ultraviolet rays are applied to the surface of the substrate holding member (9) and the entire upper surface of the transfer section (40). As a result, the entire irradiation surface is made hydrophilic, and the small pieces of residual resist, dust, and organic material abrasives existing on the surface are less likely to adhere (difficult to stick) and are easy to remove. Therefore, these foreign matters can be easily removed.

When the emission intensity of the light source (56A) can be controlled according to the detection result of the illuminance detecting means (53), the integrated value of the detection results of the illuminance detecting means (53) reaches a predetermined value. The light source (56A) is caused to emit light to control the integrated irradiation amount. Further, when the cooling means (42, 45) for cooling the substrate holding member (9) based on the detection result of the temperature detecting means (46) is provided, the temperature of the substrate holding member (9) is changed by the irradiation of ultraviolet rays. So as not to rise too much,
The substrate holding member (9) is cooled.

Next, according to the third cleaning apparatus for the exposure apparatus of the present invention, the driving means (21) for wiping (or shaving) the foreign matter with the cleaning member and the irradiation and exhaust means (22).
Since various foreign substances can be efficiently removed, the non-contact irradiation exhaust means (22) reduces the number of times the first cleaning member such as a high hardness abrasive is used. The risk of damaging the surface of the substrate holding member (9) is greatly reduced. Further, it is also possible to carry out only the non-contact cleaning, and the substrate holding member (9) can be automatically and easily cleaned by selecting an appropriate cleaning method in various combinations according to the situation of contamination. .

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cleaning device for an exposure apparatus according to the present invention will be described below with reference to the drawings. In this example, the present invention is applied to a cleaning device for a wafer holder of a projection exposure apparatus. FIG. 1 shows a main part of a projection exposure apparatus provided with the cleaning device of the present embodiment. In FIG. 1, a reticle pattern (not shown) under illumination light for exposure passes through a projection optical system 11. Then, each shot area of the wafer 10 is projected and exposed. The Z axis is taken parallel to the optical axis of the projection optical system 11, and the Cartesian coordinate system in the plane perpendicular to the Z axis is the X axis and the Y axis.

First, the base 1 is installed on a vibration isolation table (not shown), and the Y stage 2, the X stage 4, and the
A Z stage 6, a rotary plate 7 (see FIG. 2), a tilt plate 8 and a wafer holder 9 are installed, and a wafer 10 is suction-held on the wafer holder 9. In this case, the Y stage 2 is driven by the drive motor 3 in the Y direction, the X stage 4 is driven by the drive motor 5 in the X direction, the Z stage 6 positions the wafer 10 in the Z direction, and the rotary plate 7 and the tilting plate are tilted. The plate 8 corrects the rotation angle and the inclination angle of the wafer 10, respectively. Further, an X-axis moving mirror 12X and a Y-axis moving mirror 12Y are fixed on the Z stage 6, and the interferometers 13X and 1 are respectively fixed by the moving mirrors 12X and 12Y.
The measurement laser beams LBX and LBY from 3Y are reflected, and the X coordinate and Y coordinate of the Z stage 6 are constantly monitored by the interferometers 13X and 13Y, respectively.

A plurality of grooves (not shown) for adsorption are also formed on the surface of the wafer holder 9 of this embodiment, and the exhaust holes in these grooves are connected to a vacuum pump (not shown). Also,
As shown in FIG. 2A, an elevating table 38 is attached so that it can be moved in the Z direction by a drive motor 39 along an L-shaped guide 37 fixed to the upper surface of the X stage 4. Three pin-shaped wafer transfer parts 40 are planted on the upper surface of the. Each of these three wafer transfer parts 40 is inserted into a through hole provided in the wafer holder 9, and the wafer transfer part 40 extends from the position lower than the protruding part of the wafer holder 9 along the Z direction by a predetermined width from the protruding part. It is possible to stop at any position up to a high position. In addition, exhaust holes for vacuum suction are formed in the center of the wafer transfer part 40, and these exhaust holes are connected to a vacuum pump (not shown) via an exhaust duct 41.

Further, a temperature sensor 46 such as a thermistor or a thermocouple is embedded near the surface of the wafer holder 9, and a cooling hose 42 for supplying a fluid (cooling liquid) such as Fluorinert for cooling the wafer holder 9 is provided on the bottom surface of the wafer holder 9. It is connected. Returning to FIG. 1, the oblique incidence type focus position detection system including the projection optical system 14 and the light receiving optical system 16 is arranged on the side surface of the projection optical system 11. From the projection optical system 14 to the wafer 10 located at the exposure center of the projection optical system 11.
A slit image 15 is obliquely projected onto the optical axis of the projection optical system 11 with respect to the upper measurement point, and the reflected light from the wafer 10 reimages the slit image 15 in the light receiving optical system 16. When the wafer 10 is displaced in the Z direction, the light receiving optical system 16
The position of the slit image re-formed inside is laterally displaced, and the light receiving optical system 16 outputs a focus signal corresponding to the lateral displacement amount. Therefore, from the focus signal, the focus position (Z-direction position) of the wafer 10 at the measurement point
Is detected. In the present embodiment, the X stage 4 and the Y stage 2 are driven, and the distribution of the focus position on the entire surface of the wafer 10 is measured by the focus position detection system thereof, whereby the flatness (flatness) of the surface of the wafer 10 is measured. ) Is measured.

Next, a cleaning device 17 is arranged on the front side of the base 1 of the projection exposure apparatus. In this cleaning device 17, a Z-axis driving unit 18 is installed in the vicinity of the base 1, a vertical moving shaft 19 is provided on the Z-axis driving unit 18 so as to be movable in the Z direction, and is rotated around the vertical moving shaft 19. Two rotating arms 20A and 20B are attached so that they can be freely fixed at a desired rotation angle.
The amount of movement of the vertical movement shaft 19 in the Z direction and the rotation arm 20A
The rotation angles of 20 and 20B are controlled by the control unit 43.

A scrub unit 21 is fixed to the bottom surface of the tip of one rotating arm 20A, and an irradiation unit 22 for irradiating ultraviolet rays is fixed to the bottom surface of the tip of the other rotating arm 20B. In this case, the wafer 10 is taken out from the wafer holder 9 and the X stage 4
Is moved in the + X direction and the Y stage 2 is moved in the -Y direction, and the vertical movement shaft 19 is slid downward, so that the scrub unit 21 can be mounted on the wafer holder 9. Then, the vertical drive shaft 19 is slid upward, the rotary arm 20A is rotated clockwise, and then the rotary arm 20B is rotated clockwise to slide the vertical moving shaft 19 downward.
The irradiation unit 22 can be mounted on the wafer holder 9. That is, in this embodiment, the vertical movement shaft 19,
By operating the rotary arms 20A and 20B, either the scrub unit 21 or the irradiation unit 22 can be mounted on the wafer holder 9. Further, the pressure contact force at that time can be adjusted by the position of the vertical moving shaft 19 in the Z direction. In the example of FIG. 1, the rotary arms 20A and 20B
Can only rotate and move up and down, but the rotating arm 2
A slide mechanism may be provided in the middle of 0A and 20B so that the rotary arms 20A and 20B can further advance and retreat in the radial direction.

Next, referring to FIG. 2, the scrub unit 2
The configuration 1 will be described in detail. 2A is a sectional view showing a state in which the scrub unit 21 is mounted on the wafer holder 9, and FIG. 2B is a bottom view taken along the line AA of FIG. 2A. In FIG. 2A, the upper frame 23 is screwed to the bottom of the rotating arm 20A, and the shield cover 24A is attached so as to cover the upper frame 23. Further, the drive motor 26 is fixed to the upper end of the rotary arm 20A, the gear 27A is fitted to the drive shaft of the drive motor 26, and the gear 27A has three gears (two gears 27B in FIG. 2A). 27C only appearing) and these gears are driven in a planetary gear system. The drive system can be replaced by a belt system or a planetary roller system.

The middle frame 30 is fixed to the bottom surfaces of the gear 27A and the other three gears via bearings 29A, and the lower frame 34 is fixed to the bottom surface of the middle frame 30. To gears 27A to 27
The drive roller 2 is attached to each of C and the shaft of another gear (not shown).
8A to 28C and a drive roller (not shown) are connected. Then, on the bottom surface of the drive roller 28A, as shown in FIG. 2B, plate-shaped organic material abrasives 32A, 32D each having a quadrant shape, and high hardness abrasives 33A, 33 are provided.
C is fixed so as to be a disk as a whole, and the disk-shaped organic material abrasives 32B and 32C are fixed to the bottom surfaces of the drive rollers 28B and 28C, respectively. The hardness abrasive 33B is fixed. As the organic material abrasives 32A to 32D, a polyvinyl alcohol (PVA) brush, a nylon brush, a sponge, or the like can be used. On the other hand, a grindstone or the like can be used as the high hardness abrasives 33A to 33C.

The organic material abrasives 32A to 32D and the high hardness abrasives 33A to 33C are arranged in parallel on the wafer holder 9.
Is pressed against the surface of the convex portion. At this time, the tip of the wafer transfer part 40 is also set at the same height as the surface of the convex portion of the wafer holder 9, so that the tip of the wafer transfer part 40 can be cleaned. In addition, a strain gauge, a pressure sensor 31 such as a semiconductor pressure sensor is arranged between the gear 27C and the middle frame 30, and the pressure sensor 31 causes the abrasives 32A to 32D and 33A to 33C to project from the convex portion of the wafer holder 9. The pressure contact force with respect to the surface of the wafer transfer part 40 is detected, and a detection signal is supplied to the control part 43 of FIG. The control unit 43 adjusts the position of the vertical movement shaft 19 so that the detection signal of the pressure sensor 31 becomes a level corresponding to a predetermined pressure contact force.

Further, a shield hood 36A is attached to the outside of the shield cover 24A so as to oppose the side surface of the lower frame 34, and a pressure for detecting the pressure contact force between the inclined plate 8 and the shield hood 36A is attached to the shield hood 36A. A sensor 35A is installed, and the detection signal of this pressure sensor 35A is also supplied to the control unit 43 in FIG. In this case, abrasives 32A-3
In the state where 2D and 33A to 33C are pressed against the surface of the convex portion of the wafer holder 9 with a predetermined pressing force, the shielding hood 36A is pressed against the inclined plate 8 with another predetermined pressing force. . As a result, the inside of the shield cover 24 and the shield hood 36A is sealed when the wafer holder 9 is cleaned. The control unit 43 in FIG. 1 can also move the scrub unit 21 up and down according to the detection output of the pressure sensor 35A.

Further, the exhaust hole in the upper part of the upper frame 23 is
Connected to a suction device (not shown) via the exhaust duct 25,
Through the exhaust duct 25, all the foreign substances, dust, etc. generated in the shield cover 24 and the shield hood 36A are sucked. Further, an exhaust pressure sensor (not shown) is connected to the exhaust duct 25, and the exhaust pressure sensor monitors exhaust gas. The exhaust pressure sensor can be replaced by an exhaust flow velocity sensor.

In this embodiment, by rotating the drive motor 26 shown in FIG. 2 (a), the organic material abrasives 32A and 32D and the high hardness abrasive 33 as shown in FIG. 2 (b).
The disk made of A and 33C rotates clockwise, whereby the organic material polishing material 32B, the organic material polishing material 32C, and the high hardness polishing material 33B rotate counterclockwise,
Moreover, these organic material abrasives 32B and organic material abrasives 32
C and the high hardness abrasive 33B are synchronized with the lower frame 34.
It rotates in the direction of θ through the ring-shaped opening. As a result, the entire surface of the wafer holder 9 is alternately cleaned with the organic material polishing material and the high hardness polishing material. Further, all the foreign matter, dust, etc. generated at this time are sucked through the exhaust duct 25.
Therefore, various foreign substances are efficiently and almost completely dropped from the projection of the wafer holder 9 and the surface of the wafer transfer unit 40, and the dropped foreign substances are not discharged to the outside and reattached.

Next, the structure of the irradiation unit 22 will be described in detail with reference to FIGS. 3 and 4. 3 is a cross-sectional view showing a state in which the irradiation unit 22 is mounted on the wafer holder 9 and the height of the tip of the wafer transfer portion 40 is adjusted to the height of the convex portion of the wafer holder 9, and FIG. FIG. 6 is a cross-sectional view showing a state where a wafer transfer part 40 is raised in the Z direction with respect to FIG.

In FIG. 3, the frame 51 is screwed to the bottom surface of the rotary arm 20B, the shield cover 24B is attached to the side surface of the frame 51, and four ultraviolet rays are attached to the lamp holding metal fitting 55 fixed inside the shield cover 24B. Lamps 56A and 56B (the other two are arranged in a direction perpendicular to the paper surface of FIG. 3) are held. Shield cover 24
A reflecting plate 54 that reflects ultraviolet rays downward is disposed between B and the ultraviolet lamps 56A and 56B, and an ultraviolet light quantity sensor 53 including a photodiode or the like is provided in the frame 51 through an opening in the reflecting plate 54. There is. A detection signal corresponding to the illuminance at the ultraviolet light quantity sensor 53 is supplied to the power supply unit 44, and the power supply unit 44 supplies power to the ultraviolet lamps 56A and 56B so that the illuminance becomes a predetermined value.

Further, a shield hood 36B is provided so as to cover the shield cover 24B to the inclined plate 8, and a pressure sensor 35 for detecting a pressure contact force on the surface of the shield hood 36B.
B is attached, and the detection signal of the pressure sensor 35B is also shown in FIG.
Is supplied to the control unit 43. The control unit 43 adjusts the position of the vertical movement shaft 19 based on the detection signal from the pressure sensor 35B so that the pressure contact force from the shield hood 36B to the inclined plate 8 becomes a predetermined pressure contact force.

In FIG. 3, ultraviolet lamps 56A and 56A are provided.
When B is turned on, ozone (O
₃ ), carbon dioxide (CO ₂ ) and water vapor (H ₂ O) are generated, but their diffusion is prevented by the shielding cover 24B and the shielding hood 36B. Further, a suction pump (not shown) is connected to a central portion of the frame 51 and a hole penetrating the rotary arm 20B via an exhaust duct 52, and gas generated in the shield cover 24B and the shield hood 36B is exhausted. It is adapted to be discharged to the outside through the duct 52.

Further, the temperature sensor 46 in the wafer holder 9
Is supplied to the cooling device 45,
When the temperature of the wafer holder 9 exceeds the allowable value,
The cooling liquid is supplied to the bottom surface of the wafer holder 9 via the cooling hose 42. This prevents the temperature of the wafer holder 9 from rising due to the irradiation of ultraviolet rays. In the scrub unit 21 of FIG. 2, the tip of the wafer transfer part 40 could be cleaned, but the side surface thereof was difficult to clean. On the other hand, in the irradiation unit 22 of this example,
As shown in FIG. 4, by holding the tip end portion of the wafer transfer part 40 so as to protrude from the upper surface of the wafer holder 9 by a height H, the ultraviolet rays are applied not only to the upper surface (adsorption surface) of the wafer transfer part 40 but also to the side surface thereof. It can be irradiated. As a result, foreign matter on the side surface of the wafer transfer part 40 can also be removed.

Next, an example of the operation in the case of cleaning the upper surfaces of the wafer holder 9 and the wafer transfer section 40 of the projection exposure apparatus in this embodiment will be described with reference to the flowcharts of FIGS. 7 and 8. This flowchart shows the operation when the projection exposure apparatus is provided with both the ultraviolet irradiation unit 22 and the scrub unit 21, and the two units are switched and used.

First, in step 101 of FIG. 7, after the wafer 10 to be exposed is transferred from the wafer loader system (not shown) to the wafer transfer section 40 (see FIG. 4) protruding above the wafer holder 9 of FIG. Wafer transfer unit 4
0 is lowered and the wafer 10 is vacuum-adsorbed on the wafer holder 9. After that, while moving the wafer 10 two-dimensionally through the Y stage 2 and the X stage 4, the flatness (flatness) of the wafer 10 is passed through the focus position detection system including the projection optical system 14 and the light receiving optical system 16. To measure. In the next step 102, if the flatness measurement result is within a predetermined allowable value, step 103
Then, the exposure sequence for the wafer 10 is continued.

However, if the flatness measurement result exceeds the allowable value, the process proceeds to step 104, and it is determined whether the projection exposure apparatus of this example is set to the automatic cleaning mode. If the automatic cleaning mode is not set, the process proceeds to step 112, and a warning message indicating that the flatness exceeds the allowable value is displayed, and then step 11
In step 3, a process stored in advance in the host computer or a process instructed by the operator by an operator call is executed, and in step 114 thereafter, the exposure ends.

On the other hand, when the automatic cleaning mode is set in step 104, the value of the cleaning set number parameter prepared to prevent damage due to excessive cleaning of the wafer holder 9 is evaluated in step 105. When the value of the cleaning set number of times parameter has already been counted up to the predetermined set value, the process proceeds to step 112, a warning is displayed, and then the process proceeds to step 113. When the value of the cleaning set number of times is less than or equal to the set value, the flatness is re-measured using the same wafer 10 in step 106. If the re-measured result is within the allowable value, the process proceeds to step 102, and the subsequent sequence is as described above.

However, if the remeasurement result deviates from the allowable value again, the process proceeds to step 107 to store the measured wafer 10 in an unload cassette (not shown), and then in step 108, the scrub unit 21. Are automatically mounted on the wafer holder 9. That is, the X stage 4 and the Y stage 2 respectively move to the cleaning position, and after the rotating arm 20A of the scrub unit 21 rotates toward the wafer holder 9, the scrub unit 21 moves vertically downward to the wafer holder 9 side together with the vertical movement shaft 19. Move to Figure 2
The state becomes as shown in (a).

At the time of exposure, the scrub unit 21
As shown in FIG. 1, the UV irradiation unit 22 and the UV irradiation unit 22 stand by outside the movement stroke range of the X stage 4 and the Y stage 2, and do not interfere with the exposure operation at all. After the scrub unit 21 is mounted as shown in FIG. 2A, in step 109, the high hardness abrasives 33A to 33C and the organic material abrasives 32A to 3A shown in FIG.
The pressure sensor 31 detects the pressure contact force with respect to the 2D wafer holder 9.
The pressure contact force of the shielding hood 36A against the inclined plate 8 is detected by the pressure sensor 35A. If it is determined that either one of the detection results does not match the predetermined pressure contact force within the predetermined allowable range, the process proceeds to step 112 and a warning or the like is performed.

When both the pressure contact forces match the set pressure contact force, it is further determined by the detection signal of the exhaust pressure sensor (not shown) whether or not the exhaust by the exhaust duct 25 is normal. Exhaust by the exhaust duct 25 is started immediately before mounting the scrub unit 21. If the exhaust gas is not normal, the routine proceeds to step 112, where error countermeasures are executed, and if the exhaust gas is normal, the routine proceeds to step 110, where the scrub unit 21 is operated until a preset scrub setting time elapses. The drive motor 26 is rotated to scrub (wipe and scrape) the upper surfaces of the wafer holder 9 and the wafer transfer part 40. At this time, the drive rollers 28A, 28B, ... Rotate respectively, and the peripheral drive rollers 28B, 28C, ... Perform planetary rotation, so that the high hardness abrasives 33A-33C and the organic material abrasives 32A-32D are The surfaces of the wafer holder 9 and the wafer transfer part 40 are slid. After scrub, step 111
In step 3, the scrub unit 21 is moved upward from the wafer holder 9 and further raised and rotated to move the scrub unit 21 to the original standby position.

Next, in step 115 of FIG. 8, the ultraviolet irradiation unit 22 is automatically mounted on the wafer holder 9. As described above, at the time of exposure shown in FIG. 1, the irradiation unit 22 also stands by outside the range of the movement stroke of the X stage 4 and the Y stage 2, and holds the state in which the exposure operation is not disturbed at all. The method of automatically mounting the irradiation unit 22 is the same as that of the scrub unit 21.

In the subsequent step 116, a more detailed partial exhaust check than the exhaust check in step 109 for the scrub unit 21 is performed by software. This is because the following chemical reaction is performed inside the shield cover 24B and the shield hood 36B in FIG. 3 (or FIG. 4). That is, when the ultraviolet lamps 56A and 56B start emitting light, wavelengths of 185 nm and 254 nm are used in this example.
Ultraviolet rays of the above continuously emit light, and each wavelength causes the following two chemical reactions in succession. However, in the following formula,
h is Planck's constant, ν is the frequency of light, and hν is the energy of the light.

[0045]

[Chemical formula 1] 3O ₂ + hν (wavelength 185 nm) → 2O ₃

[0046]

Embedded image O ₃ + hν (wavelength 254 nm) → O ₂ + O ^{* In} this formula, O ^* represents atomic oxygen. This means that ozone (O ₃ ) and atomic oxygen (O ^* ) are generated in the shield cover 24B and the shield hood 36B.

At the same time, the residual resist on the wafer holder 9 and the wafer transfer section 40, and the organic material polishing material 32A.
Since both of the separated pieces of .about.32D (18a) are organic substances, the following chemical reactions are caused in addition to the above-mentioned chemical reactions. That is, organic substances (hydrocarbons, etc.) are carbon C, hydrogen H,
Although it is composed of atoms of oxygen and oxygen, the bond energy of C—H and the like is smaller than the above-mentioned ultraviolet energy hν, so that individual bonds are broken as follows.

[0048]

[Chemical formula 3] C−H + hν (wavelength 254 nm and 185 n
m) → C + H Further, the carbon atom (C) and the hydrogen atom (H) thus cut off are combined with ozone (O ₃ ) and atomic oxygen (O ^* ) generated by the above chemical reaction, Thus, carbon dioxide (CO ₂ ) and water (H ₂ O) are generated.

[0049]

## STR00004 ## C + 2H + O ₂ + O ^* → CO ₂ + H ₂ O Although the above chemical reaction is generally known, in order to remove the above reaction products from the wafer holder 9, exhaust gas is exhausted through the exhaust duct 52. Has been done. In the unlikely event that exhaust has not been performed sufficiently (normally), step 1 in Fig. 1
The process shifts to 12 and a warning is displayed and the above-mentioned processing is performed.
If the exhaust is sufficiently performed, the process proceeds to step 117 and the ultraviolet lamps 56A and 56B are turned on. The power (current) supplied at this time is, for example, a predetermined constant standard power. Next, at step 118, the detection signal of the ultraviolet light quantity sensor 53 is monitored.

After that, when the illuminance of the ultraviolet lamps 56A and 56B is normal, heat is generated during the ultraviolet irradiation process. Therefore, it is determined in step 119 based on the detection signal of the temperature sensor 46 whether the temperature of the wafer holder 9 is normal. judge. At this time, the wafer holder 9 by the cooling device 45
However, if the temperature of the wafer holder 9 still rises above the set value, the cooling capacity of the cooling device 45 is increased. If it is still insufficient, the emission power of the ultraviolet lamps 56A and 56B is lowered to continue irradiation. Even if such measures are taken, if the temperature of the wafer holder 9 becomes too high, step 1
After performing the warning display at 20, the process proceeds to step 122 and the irradiation of the ultraviolet lamps 56A and 56B is stopped. If the temperature of the wafer holder 9 is normal, the routine proceeds to step 121, where it is determined whether or not the ultraviolet irradiation time has ended.

In this embodiment, the ultraviolet lamps 56A and 56B are arranged so that a preset cumulative irradiation energy can be obtained.
The irradiation time is controlled. Generally, an ultraviolet lamp (particularly a low-pressure mercury lamp) has a variation characteristic of irradiation power with respect to a lighting time T as shown in FIG. 5, and when the supply power and the irradiation time are the same, integrated irradiation from the initial time t ₀ The amount is totally different from the integrated irradiation amount from time t ₁₀₀₀ after lighting for 1000 hours, for example. Therefore, by integrating the detection signal of the ultraviolet light amount sensor 53, it is determined that the irradiation time has ended when the desired integrated irradiation amount is obtained.

Specifically, as shown in FIG. 6, when the ultraviolet lamp starts to emit light at time t ₀ , its irradiation amount [mW
/ Cm ² ] changes like a curve 57A, and when the ultraviolet lamp starts emitting light at time t ₁₀₀₀ , the irradiation amount changes like a curve 57B, and the convergent value of the curve 57B changes to the curve 57B.
It is smaller than the convergence value of A. Therefore, in order to obtain a predetermined integrated dose, the irradiation time is set to T1 when the irradiation is started from time t _0, and the irradiation time is set to T2 (T2> T1) when the irradiation is started from time t _1000. The integrated area 58A of the curve 57B and the integrated area 58B of the curve 57B may be made equal. In this case, the integrated areas 58A and 58B
Is a value obtained by multiplying the integrated value of the detection signal of the ultraviolet light amount sensor 53 by a predetermined coefficient, so that the integrated value of the detection signal of the ultraviolet light amount sensor 53 is a predetermined value at any point of irradiation. The irradiation time may be set so that

If the predetermined integrated irradiation amount has not been reached, the process returns to step 116, and the operations of steps 116 to 119 are repeated until the predetermined integrated irradiation amount is obtained. At this time, in step 118, the ultraviolet light amount sensor 5
The detection signal of No. 3 is used to detect the defect or life of the ultraviolet lamps 56A and 56B. That is, when the ultraviolet lamps 56A and 56B are not lit, or the amount of emitted light is significantly reduced and the irradiation time becomes too long,
The process described above is performed after the process proceeds to step 112 in FIG. 1 to display a warning.

When the cumulative irradiation dose reaches a predetermined value in step 121 and the irradiation time ends, step 122
At step 123, the irradiation of ultraviolet rays is stopped, and the process waits while continuing exhausting through the exhaust duct 52 for a preset time. This is because the wafer holder 9 and the like may not be cooled immediately even if the ultraviolet lamps 56A and 56B are turned off, and the above-described reaction product may remain inside the shield cover 24B and the shield hood 36B. is there.

After the irradiation unit 22 is mounted on the wafer holder 9, that is, after the irradiation unit 22 is on standby for a set time at the ultraviolet irradiation position, the irradiation unit 22 is detached upward from the wafer holder 9 in step 124, and The irradiation unit 22 is rotated and raised to move to the original standby position shown in FIG. Next Step 1
In step 25, in the case other than the ultraviolet irradiation stop due to various abnormalities, that is, in the case of normal termination, the state of cleaning is recorded in the control unit of the projection exposure apparatus main body in step 126, and after completion of cleaning display, step The process will move to 101 again. The sequence shown in FIGS. 7 and 8 is one of the selectable sequences, and a combination of various operations is selected at any time according to the contamination state of the surface of the wafer holder 9 or the wafer transfer unit 40. It is possible to For example, since the automatic cleaning mode has been turned off for a long period of time, the surface of the wafer holder 9 may be a hydrophobic surface after the state where the wafer holder 9 has not been cleaned. It is possible to select a sequence of performing scrub cleaning using the scrub unit 21 after performing ultraviolet irradiation using the irradiation unit 22.

Further, the wafer transfer unit 4 is irradiated with the ultraviolet rays.
It is also possible to provide a sequence in which the organic substance (residual resist or dust) attached to the inside of the opening for the wafer transfer unit 40 in the wafer holder 9 and the side surface of the wafer transfer unit 40 as well as the tip end thereof is removed by moving 0 up and down. Good. It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various configurations can be adopted without departing from the gist of the present invention.

[0057]

According to the first cleaning apparatus for the exposure apparatus of the present invention, the solid cleaning member and the cleaning member containing the organic material are pressed against the substrate holding member in parallel and slid. However, there is an advantage that foreign matter such as residual resist and dust, which has been difficult to remove conventionally, can be automatically and easily removed.
Further, since the pressure contact force of the solid cleaning member can be controlled, the pressure contact force can be adjusted according to the foreign matter, and the substrate holding member can be prevented from being damaged.

Furthermore, since the stage on the substrate holding member side can be cleaned while stopped, the risk of mutual damage due to mechanical interference between the stage and the cleaning device can be significantly reduced. Further, when the exhaust means is provided, the foreign matter removed from the surface of the substrate holding member is discharged together with the surrounding gas, so that the foreign matter thus removed does not adhere to other areas again.

Next, according to the second cleaning apparatus for the exposure apparatus of the present invention, the foreign matter is decomposed into carbon dioxide, water vapor and the like by irradiation of ultraviolet rays, and these gases are exhausted. There is an advantage that it is possible to easily remove the residual resist, dust, and the like that have entered a place such as a vacuum suction groove or a vacuum suction hole on the holding member (wafer holder) that cannot be cleaned with an abrasive.

At the same time, the surface of the substrate holding member (wafer holder, wafer transfer portion) is made hydrophilic by the chemical reaction caused by the irradiation of ultraviolet rays, so that residual resist, dust, etc. are less likely to adhere (difficult to stick). . In addition, since it becomes easier to remove the adhered resist and dust, it is possible to reduce the cleaning frequency. At this time, by controlling the light emission intensity of the light source based on the detection result of the illuminance detection means, for example, the irradiation can be stopped when the integrated irradiation amount reaches a predetermined value.
Further, when the substrate holding member is cooled based on the temperature of the substrate holding member, it is possible to prevent the temperature rise of the substrate holding member due to the irradiation of ultraviolet rays.

Furthermore, according to the third cleaning apparatus for the exposure apparatus of the present invention, the method of sliding a plurality of cleaning members and the method of irradiating ultraviolet rays can be switched and used, so that various foreign substances are automatically detected. In addition, there is an advantage that it can be easily removed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a projection exposure apparatus including an embodiment of a cleaning device according to the present invention.

2A is a cross-sectional view showing a state in which a scrub unit 21 is mounted on a wafer holder 9, and FIG. 2B is FIG. 2A.
It is a bottom view which followed the AA line of.

FIG. 3 shows an ultraviolet irradiation unit 22 on the wafer holder 9.
FIG. 4 is a cross-sectional view showing a state in which is mounted and the height of the wafer transfer part 40 is adjusted to the height of the wafer holder 9.

FIG. 4 is an enlarged cross-sectional view showing a case where the height of the wafer transfer part 40 is made higher than that of the wafer holder 9 from the state of FIG.

FIG. 5 is a diagram showing a change in irradiation power with respect to a lighting time of a general ultraviolet lamp.

FIG. 6 is a diagram for explaining a method of controlling the irradiation amount of ultraviolet rays according to an embodiment of the present invention.

FIG. 7 is a flowchart showing the first half of an example of the operation when cleaning is performed by switching between the scrub unit and the ultraviolet irradiation unit.

FIG. 8 is a flowchart showing a second half of an example of an operation in which cleaning is performed by switching between the scrub unit and the ultraviolet irradiation unit.

[Explanation of symbols]

 2 Y stage 4 X stage 6 Z stage 7 Rotating plate 8 Tilt plate 9 Wafer holder 10 Wafer 11 Projection optical system 14 Projection optical system of focus position detection system 16 Light receiving optical system of focus position detection system 17 Cleaning device 19 Vertical movement axis 20A, 20B Rotating arm 21 Scrub unit 22 Irradiation unit 24A, 24B Shielding cover 25, 52 Exhaust duct 31, 35A, 35B Pressure sensor 32A-32D Organic material abrasive 33A-33C High hardness abrasive 36A, 36B Shielding hood 40 Wafer passing part 42 Cooling hose 45 Cooling device 46 Temperature sensor 53 UV light intensity sensor 56A, 56B UV lamp

Claims (6)

[Claims] 1. An exposure device for exposing a mask pattern onto a photosensitive substrate held on a substrate holding member,
In a device for cleaning the surface of the substrate holding member, a solid first cleaning member, a second cleaning member containing an organic material, and the first and second cleaning members are provided in the substrate holding member. Pressurizing means for contacting and biasing the surface, driving means for moving the first and second cleaning members on the surface of the substrate holding member, and pressure contact applied to the surface of the substrate holding member by the pressing means. Pressure contact force detecting means for detecting force, and pressure contact force control means for controlling the pressure contact force applied to the substrate holding member from the pressure applying means based on the pressure contact force detected by the pressure contact force detecting means. A cleaning device for an exposure apparatus, which is characterized by: 2. An exhaust means for sucking and exhausting gas in the vicinity of the substrate holding member is provided.
A cleaning device for the exposure apparatus described. 3. An exposure device, which exposes a mask pattern onto a photosensitive substrate held on a substrate holding member,
In a device for cleaning the surface of the substrate holding member, a light source that irradiates the surface of the substrate holding member with ultraviolet light, and a space from the surface of the substrate holding member to the light source and a space outside thereof are substantially blocked. A cleaning device for an exposure apparatus, comprising: a shielding member for controlling the exposure of the substrate holding member covered with the shielding member; 4. An illuminance detection means for detecting the illuminance of ultraviolet rays emitted from the light source, and a light source control means for controlling the emission intensity of the light source based on the illuminance detected by the illuminance detection means. The cleaning device for an exposure apparatus according to claim 3, wherein: 5. A temperature detecting means for detecting a temperature of the substrate holding member, and a cooling means for cooling the substrate holding member based on a detection result of the temperature detecting means. A cleaning device for the exposure device according to 3 or 4. 6. An exposure device for exposing a mask pattern onto a photosensitive substrate held on a substrate holding member,
In the apparatus for cleaning the surface of the substrate holding member, a driving unit that moves the first cleaning member in a solid state and the second cleaning member containing an organic material in contact with the surface of the substrate holding member; A light source that irradiates the surface of the substrate holding member with ultraviolet light, a shielding member that substantially shields the space from the surface of the substrate holding member to the light source and the space outside thereof, and the shielding member covered with the shielding member. Irradiation evacuation means having exhaust means for sucking and exhausting gas near the surface of the substrate holding member; switching means for alternately mounting the driving means and the irradiation evacuation means on the surface of the substrate holding member. A cleaning device for an exposure apparatus, which is characterized in that