JP2002289493A - Substrate cooler and substrate cooling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate cooler and a substrate cooling method capable of performing a cooling process with good surface-uniformity for a short time with suppressing electrostatic charge. SOLUTION: The substrate cooler comprises a cooling plate 12 having a mounting surface 1a for mounting a substrate W, a vacuuming mechanism 12 for evacuating through vacuum holes 10 formed at the mounting surface 1a to vacuum the substrate to the mounting surface, and support pins 3 for contacting/separating the substrate W relative to the mounting surface 1a. A controller 20 controls the operation of the vacuuming mechanism 12 and the vertical motion of the support pins 3. The controller 20 holds the vacuuming mechanism 12 nonactive for a first time in a state that the substrate W is mounted on the mounting surface 1a (non-vacuumed cooling process) and then actuates the mechanism 12 for a second time to vacuum the substrate W to the mounting surface 1a (vacuumed cooling process).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor wafer,
A substrate cooling device and a substrate cooling device for cooling various substrates such as a glass substrate for a liquid crystal display device, a glass substrate for a plasma display panel, a glass substrate for a photomask, a substrate for an optical disk, a substrate for a magnetic disk, and a substrate for a magneto-optical disk. About the method.

[0002]

2. Description of the Related Art For example, in a manufacturing process of a liquid crystal display device, a photolithography for forming a fine thin film pattern on the surface of a rectangular glass substrate (hereinafter, simply referred to as "substrate") is performed. Lithographic processing is essential. In the photolithography process, a photoresist is applied to the substrate surface. Prior to this, the substrate is subjected to a cleaning process and a heat drying process. The substrate after the heating and drying treatment is cooled to room temperature by the substrate cooling device.

[0003] Substrate cooling devices are roughly classified into a proximity type and a contact type. The proximity type substrate cooling device includes a cooling plate and a support member that supports the substrate while maintaining a small distance from the surface of the cooling plate. That is, in the proximity type substrate cooling device, the substrate is subjected to a cooling process without contacting the surface of the cooling plate. On the other hand, a contact-type substrate cooling device includes a cooling plate, suction holes formed on the surface of the cooling plate,
An exhaust device is provided which vacuum-adsorbs the substrate to the surface of the cooling plate by exhausting through the suction holes.

In a contact-type substrate cooling device, when the substrate contracts during the cooling process, friction occurs between the substrate and the cooling plate in a state where the substrate surface is attracted to the surface of the cooling plate. Due to this friction, a large amount of static electricity is generated, and particles floating in the air are attracted to the surface of the substrate, which causes a problem that the quality of the substrate is impaired. Also,
When the substrate is lifted away from the cooling plate, the substrate is likely to be misaligned, which may cause a failure in the transfer between the substrate cooling device and the robot that transports the substrate, resulting in poor transport. There is also a problem that it is easy.

On the other hand, in the proximity type substrate cooling device, a large amount of static electricity is not generated because the cooling plate and the substrate are not in contact with each other, and therefore, when the substrate is moved up and down with respect to the cooling plate. Is unlikely to occur. However, as compared with the contact type substrate cooling apparatus, the processing time required for completing the cooling or temperature control processing is longer, and the substrate type is inferior to the contact type in terms of the in-plane uniformity of the substrate surface temperature.

Japanese Patent Application Laid-Open No. 5-182900 discloses an apparatus for precooling a substrate by holding the substrate above a cooling plate and then adsorbing the substrate to the surface of the cooling plate to cool the substrate. However, there is no difference from the above-mentioned contact type substrate cooling device in that the substrate shrinks in a state in which the substrate is in close contact with the surface of the cooling plate. Can not overcome.

An object of the present invention is to provide a substrate cooling apparatus and a substrate cooling method capable of performing a cooling process with good in-plane uniformity in a short time while suppressing generation of static electricity.

[0008]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided an image forming apparatus having a mounting surface (1a) on which a substrate (W) is mounted. A cooling plate (1) for cooling the substrate on the mounting surface, and suction means for sucking the substrate on the mounting surface by exhausting air through suction holes (10) formed in the mounting surface. 12), substrate holding means (3) for holding the substrate, and displacing the substrate so as to be in contact with or separated from the mounting surface, and controlling the substrate holding means to provide the substrate on the mounting surface. And controlling the suction means to be in an operation stop state for a first time in a state where the substrate is mounted on the mounting surface, and operating the suction means for a second time thereafter. And a control means (20) for causing the substrate to adhere to the mounting surface. It is a device. Note that the alphanumeric characters in parentheses represent corresponding components and the like in embodiments described later. Hereinafter, the same applies in this section.

According to a second aspect of the present invention, the control means includes:
By controlling the substrate holding means, the substrate is held at a position spaced a predetermined distance from the mounting surface for a third time before the substrate is mounted on the mounting surface. 2. The substrate cooling device according to claim 1, wherein the substrate is cooled. According to a third aspect of the present invention, there is provided a non-adsorption cooling step of mounting a substrate on a mounting surface of a cooling plate and cooling the substrate for a first time without adsorbing the substrate on the mounting surface. A suction cooling step of adsorbing the substrate placed on the mounting surface to the mounting surface and cooling the substrate for a second time, following the adsorption cooling step. .

According to a fourth aspect of the present invention, prior to the non-adsorption cooling step, the substrate is held at a position spaced a predetermined distance from the mounting surface and cooled for a third time. 4. The substrate cooling step according to claim 3, further comprising a step. According to the first or third aspect of the present invention, the substrate is placed on the mounting surface of the cooling plate, and the substrate is subjected to the cooling process (non- Adsorption cooling process). At this time, although the substrate shrinks due to cooling, a large amount of static electricity does not occur because the substrate is not attracted to the mounting surface.

Subsequent to the non-adsorption cooling process, the substrate is adsorbed on the mounting surface, and the cooling process (adsorption cooling process) is performed for a second time. This enables precise cooling processing, and achieves highly accurate in-plane uniformity with respect to the substrate temperature. The substrate is quickly cooled to a desired temperature by the non-adsorption cooling process and the adsorption cooling process performed by mounting the substrate on the mounting surface, and most of the substrate shrinkage in the cooling process is performed in the non-adsorption cooling process. Therefore, a large amount of static electricity is not accumulated on the substrate. Therefore, when the substrate is separated from the cooling plate, a large displacement of the substrate does not occur, so that a defective transfer of the substrate can be prevented.

Preferably, the first time is set to a time long enough to substantially complete the contraction of the substrate due to cooling. The second time is preferably determined so that sufficient in-plane uniformity of the substrate temperature is obtained. According to the second or fourth aspect of the present invention, prior to the non-adsorption cooling process, the substrate is placed at a predetermined distance from the mounting surface (preferably a position close to the mounting surface). The substrate is cooled while being held (non-contact cooling process). Thereby, when the substrate is placed on the mounting surface of the cooling plate for the non-adsorption cooling process, since the substrate shrinkage due to the cooling is almost finished, the distance between the substrate and the mounting surface of the cooling plate is reduced. Generation of static electricity due to friction can be more effectively suppressed.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an illustrative sectional view for explaining a configuration of a substrate cooling device according to an embodiment of the present invention. This substrate cooling device is a device for cooling a substrate W such as a rectangular glass substrate used for a liquid crystal display device, and includes a cooling plate 1 having a mounting surface 1a on which the substrate W is mounted on an upper surface. Have. The cooling plate 1 has, for example, five through holes 2 in a direction perpendicular to the mounting surface 1a (that is, in a vertical direction).
Are formed. For example, the through-hole 2 is substantially smaller than the outer diameter of the substrate W in plan view looking down on the mounting surface 1a, and is substantially at each vertex of a rectangle substantially similar to the outer diameter of the substrate W and at the intersection of diagonal lines. It is formed at the position where it matches. The support pins 3 are respectively inserted through the through holes 2. The support pins 3 are provided so that the height from the mounting surface 1a to the tip 3a is equal. Support pin 3
The tip 3a is formed into a substantially spherical shape so as to make point contact with the back surface of the substrate W.

The base end of the support pin 3 is commonly supported by a support member 4. A rack shaft 5 is connected to the support member 4. The rack shaft 5 is provided to extend in the vertical direction, and its gear portion 5a has an idle gear 6
(Pinion) is engaged. The idle gear 6 has a motor pulley 8 driven by a servomotor 7.
Are engaged. Therefore, the servo motor 7 is rotated forward /
By performing the reverse rotation, the rotation of the motor pulley 8 is transmitted to the rack shaft 5 via the idle gear 6, and is converted into the vertical movement of the rack shaft 5. Therefore, the five support pins 3 move up and down along the through hole 2, and the substrate W held at the tip 3a moves up and down.

On the mounting surface 1a of the cooling plate 1, a substrate W
A plurality of suction holes 10 are formed in a distributed manner in a region where is mounted. These suction holes 10 communicate with an exhaust passage 11 formed inside the cooling plate 1.
The exhaust passage 11 is connected to a suction mechanism 12 such as a vacuum pump via an exhaust pipe 13. On the other hand, in order to maintain the cooling plate 1 at a predetermined cooling temperature, a cooling water passage (not shown) is formed inside the cooling plate 1. The cooling water whose temperature has been adjusted by the temperature controller 14 is supplied to the cooling water passage through a cooling water supply pipe 15. The cooling water discharged from the cooling water passage is returned to the temperature controller 14 via a cooling water return pipe 16.

The operations of the servo motor 7 and the suction mechanism 12 are controlled by a control unit 20 including a microcomputer and the like. The control unit 20 moves the support pin 3 up and down by controlling the servomotor 7, and thereby moves the height of the support pin 3 between the board transfer position shown in FIG. 1 and the non-contact position shown in FIG. Cooling position,
And the contact cooling position shown in FIG. Figure 1
Is a position where the substrate W can be held at an upper position sufficiently separated from the mounting surface 1a of the cooling plate 1. At this substrate transfer position, the transfer of the substrate W between the support pins 3 and a substrate transfer robot (not shown) is performed.

In the non-contact cooling position shown in FIG. 2A, the tip 3a of the support pin 3 is placed on the mounting surface 1 of the cooling plate 1.
This is an upper and lower position slightly protruding from a. When the substrate W is held by the support pins 3 at the non-contact cooling position, a gap (about 0.3 to 0.5 mm) is provided between the back surface of the substrate W and the mounting surface 1a of the cooling plate 1. Proximity gap) is formed. At this non-contact cooling position, the substrate W can be cooled by the proximity method.

The contact cooling position shown in FIG. 2B is a position where the tip 3a of the support pin 3 enters the through hole 2 and is lower than the mounting surface 1a of the cooling plate 1. . In the process of lowering the support pins 3 supporting the substrate W to the contact cooling position, the substrate W is placed on the mounting surface 1a of the cooling plate 1 and comes into contact with the mounting surface 1a. At this time, if the suction mechanism 12 is held in the non-operation state, the substrate W is cooled in a contact state where the substrate W is not adsorbed on the mounting surface 1a of the cooling plate 1, so that the substrate W is subjected to the non-adsorption cooling process Become. On the other hand, when the suction mechanism 12 is operated and the air is exhausted through the suction holes 10 in a state where the substrate W is mounted on the mounting surface 1a, the substrate W is sucked on the mounting surface 1a of the cooling plate 1. Undergoes cooling treatment.
That is, the substrate W undergoes the adsorption cooling process.

FIG. 3 is a diagram for explaining an example of the cooling process performed by the substrate cooling device, and shows a change in the temperature of the substrate W with time. The control unit 20 controls the substrate W to be processed.
Before the is loaded, the support pins 3 are held at the substrate transfer position (see FIG. 1) by controlling the servomotor 7. In this state, when the substrate W is transferred to the support pins 3, the control unit 20 controls the servo motor 7 to lower the support pins 3 to the non-contact cooling position (see FIG. 2A). The substrate W is arranged at a position close to the mounting surface 1a with a small interval. In this state, the control unit 20 keeps the operation of the servomotor 7 stopped for a time Tp (third time: for example, 15 seconds). Thus, the cooling of the substrate W by the so-called proximity method proceeds. Although the substrate W contracts with this cooling, the lower surface of the substrate W is not in contact with the mounting surface 1a, so that static electricity may be generated due to frictional contact between the substrate W and the mounting surface 1a. Absent.

After cooling by the proximity method for the time Tp, the control unit 20 controls the servomotor 7 to lower the support pins 3 to the contact cooling position shown in FIG. As a result, the substrate W is placed on the placement surface 1a and undergoes a contact cooling process. However,
At this time, the control unit 20 sets the suction mechanism 12 to the time Tc_off.
(The first time: for example, 15 seconds), and keep it inactive. That is, the substrate W undergoes the non-adsorption cooling process for the time Tc_off.

After elapse of the time Tc_off, the control unit 20 holds the support pin 3 at the contact cooling position and operates the suction mechanism 12. As a result, exhaust is performed through the suction holes 10, and the substrate W is suctioned to the mounting surface 1a. This state
The adsorption cooling process is performed for a time Tc_on (second time: for example, 20 seconds). After elapse of the time Tc_on, the control unit 20 sets the suction mechanism 12 to the stopped state,
The suction of the substrate W on the mounting surface 1a is released. After that, the control unit 20 controls the servomotor 7 to raise the support pins 3 to the board transfer position (see FIG. 1). afterwards,
The substrate transfer robot receives the substrate W from the support pins 3.

As shown in FIG. 3, time Tc_off
, The temperature of the substrate W sharply drops. The substrate W contracts due to the rapid temperature drop. At this time, since the substrate W is not attracted to the mounting surface 1a of the cooling plate 1, the substrate W and the mounting surface 1a The amount of static electricity generated by friction is very small.
Then, after the temperature is sufficiently lowered by the non-adsorption cooling process, the adsorption cooling process for the time Tc_on is performed. By this adsorption cooling process, precise cooling of the substrate W is achieved, and highly accurate in-plane uniformity with respect to the substrate temperature can be realized. Further, by performing the non-contact cooling process over the time Tp prior to the non-adsorption cooling process at the time Tc_off, the shrinkage amount of the substrate W during the non-adsorption cooling process can be suppressed. As a result, the amount of generated static electricity is further reduced.

As described above, since a large amount of static electricity is not generated during the cooling process, when the support pins 3 are lifted to separate the substrate W from the mounting surface 1a, a positional shift of the substrate W may occur. Absent. Accordingly, there is no problem in transferring the substrate W from the support pins 3 to the substrate transfer robot, and thus, a transfer failure of the substrate can be prevented. FIG. 4 shows another operation example of the substrate cooling device.
After the substrate W to be processed is transferred to the support pins 3, the control unit 20 controls the servomotor 7 to lower the support pins 3 to the non-contact cooling position shown in FIG. In this state, the substrate cooling process by the so-called proximity method is performed for a time Tp (third time: for example, 10 seconds).

Next, the control unit 20 controls the servomotor 7 to lower the support pin 3 to the contact cooling position shown in FIG. Further, the control unit 20 activates the suction mechanism 12 to perform exhaust through the suction holes 10, and causes the substrate W to be suctioned to the mounting surface 1 a of the cooling plate 1. Thus, the adsorption cooling process is performed for the time Tc_on1 (for example, 10 seconds). Thus,
By performing the adsorption cooling process for the time Tc_on1 in addition to the cooling by the proximity method over the time Tp, the temperature of the substrate W can be rapidly lowered.

Next, the control unit 20 controls the suction mechanism 12 to be in a non-operation state, and releases the suction state of the substrate W on the mounting surface 1a. As a result, the non-adsorption cooling process is performed over the time Tc_off (first time: for example, 10 seconds). By the non-adsorption cooling process, the temperature of the substrate W rapidly decreases toward the target cooling temperature. The substrate W shrinks due to the rapid temperature change, but the substrate W is not adsorbed on the mounting surface 1a, so that a large amount of static electricity caused by friction between the mounting surface 1a and the back surface of the substrate W is generated. Does not occur.

Next, the control unit 20 operates the suction mechanism 12 again to cause the substrate W to be sucked on the mounting surface 1a. This state is maintained for a time Tc_on2 (second time: for example, 20 seconds), and the temperature of the substrate W is precisely controlled to the target cooling temperature by the adsorption cooling process. That is, highly accurate in-plane uniformity of the temperature of the substrate W can be realized. In the process shown in FIG. 4, since the adsorption cooling process is performed after the substrate cooling process by the proximity method, the temperature of the substrate can be rapidly lowered, and the time required for the substrate cooling process can be reduced. can do.

The substrate W has a time Tp and a time Tc_
The temperature drops rapidly after going on1. Then, with the temperature drop, the substrate W starts to largely contract. However, when a large contraction starts, the time Tc_off
, And the friction between the substrate W and the cooling plate 1 is small because the non-adsorption cooling process is performed, so that a large amount of static electricity is not generated. As described above, one embodiment of the present invention has been described, but the present invention can be embodied in other forms. For example, in the above embodiment, the substrate cooling process is performed by the proximity method before the substrate W is brought into contact with the mounting surface 1a of the cooling plate 1, but this process may be omitted. However, since the generation of static electricity due to the shrinkage of the substrate W can be suppressed by performing the substrate cooling process using the proximity method, the substrate method using the proximity method must be used in order to minimize the amount of generated static electricity. It is preferable to perform a cooling process.

In the above embodiment, the servo motor 7 and the rack and pinion mechanism are used to raise and lower the support pin 3. However, instead of such a drive mechanism, an air cylinder is used. A drive mechanism for raising and lowering the support pin 3 may be employed. However, when the air cylinder is used, the height of the support pin 3 can be set to only about two or three steps, whereas in the configuration of the above-described embodiment using the servo motor 7, the height of the support pin 3 is set. Can be adjusted steplessly. As a result, the transfer of the substrate and the cooling of the substrate can be performed at an arbitrary height, so that there is an advantage that the degree of freedom of control is increased.

In the above embodiment, the support pins 3 having the spherical tip 3a are used as the substrate holding means for holding the substrate W. However, other types of substrate holding means may be used. Good. However, the substrate holding means for holding the substrate W has a small contact area with the substrate W and the substrate W
It is preferable that the amount of generated static electricity due to friction at the time of shrinkage due to cooling is small. From this viewpoint, the substrate holding means is preferably a rod-shaped member like the support pin 3 of the above-described embodiment, and more preferably a form capable of holding the substrate W in point contact with the substrate W.

In addition, various design changes can be made within the scope of the matters described in the claims.

[Brief description of the drawings]

FIG. 1 is an illustrative cross-sectional view for explaining a configuration of a substrate cooling device according to an embodiment of the present invention.

FIG. 2 is a view showing the upper and lower positions of support pins for supporting a substrate.

FIG. 3 is a diagram for explaining an example of a cooling process by the substrate cooling device.

FIG. 4 is a diagram for explaining another example of the cooling process by the substrate cooling device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooling plate 1a Mounting surface 2 Through hole 3 Support pin 3a Tip 4 Support plate 5 Rack shaft 7 Servo motor 10 Suction hole 11 Exhaust path 12 Suction mechanism 13 Exhaust pipe 20 Control unit W Substrate

Claims (4)

[Claims] An exhaust system has a mounting surface on which a substrate is mounted, and a cooling plate for cooling the substrate on the mounting surface, and exhausting through a suction hole formed in the mounting surface. A suction means for sucking the substrate on the mounting surface, a substrate holding means for holding the substrate, and displacing the substrate so as to be in contact with or separated from the mounting surface, and controlling the substrate holding means. Then, the substrate is placed on the placement surface, and the suction means is controlled to be in an operation stop state for a first time in a state where the substrate is placed on the placement surface, and for a second time thereafter. Control means for operating the suction means to cause the substrate to be sucked on the mounting surface. 2. The method according to claim 1, wherein the control unit controls the substrate holding unit to place the substrate between the mounting surface and the mounting surface for a third time before mounting the substrate on the mounting surface. 2. The substrate cooling apparatus according to claim 1, wherein said substrate cooling apparatus is held at a position spaced apart by a predetermined distance. 3. A non-adsorption cooling step of mounting a substrate on a mounting surface of a cooling plate and cooling the substrate for a first time without adsorbing the substrate on the mounting surface. And a suction cooling step of adsorbing the substrate placed on the mounting surface to the mounting surface and cooling the substrate for a second time. 4. The method according to claim 1, further comprising, before the non-adsorption cooling step, a non-contact cooling step of cooling the substrate for a third time while holding the substrate at a predetermined distance from the mounting surface. The substrate cooling step according to claim 3, wherein: