JPS612324A - Retaining device - Google Patents

Abstract

PURPOSE:To prevent the generation of warpage due to attraction by a method wherein a relief part, with which the circumferential part of the material to be retained is relieved, is provided on the attracting surface of a holder, thereby enabling to avoid the holder to come in contact with the protruded part formed on the back side circumferential part of the material to be retained. CONSTITUTION:A holder 1 formed almost in square-shaped plane surface is provided on a retaining device, and a suction hole 2 of square-shaped annular groove is concentrically arranged on the upper surface of the holder 1. A suction path 3 is connected to the groove bottom of said suction hole 2 and the suction path 3 is connected to a vacuum pump. A slanting surface part 4, as a relief part, is formed in such a manner that it is inclined toward the outside in the state wherein it is formed concentrically with the suction hole 2 in annular strip form. The slanting surface part 4 is provided avoiding the circumferential part on the back side of the glass substrate 6 in a suitable height. Even when a protruded part 8 is generated on the circumferential part on the back side of the glass substrate 6, it can be prevented from contacting with the holder 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a holding technique, particularly a technique for holding a plate-shaped object. and wafers and the like.

[Background technology]

In the manufacture of semiconductor devices, when a mask pattern is printed on a glass substrate using an exposure device, a device that holds the glass substrate, which is the original plate of the photomask, is used to hold the glass substrate placed on the holder. A holding device is conceivable that uses a suction port to attract and hold the material.

However, in such a holding device, if the resist applied to the front surface wraps around from the periphery of the glass substrate to the back surface, the convex portion around the back surface of the resist will be sandwiched between the glass substrate and the holder. Therefore, the inventor has revealed that there is a problem in that the adsorption causes the glass substrate to warp and become depressed in the center.

[Purpose of the invention]

An object of the present invention is to provide a holding technique that can prevent an object to be held from being warped and deformed due to adsorption.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

In other words, by providing an escape part on the suction surface of the holder to escape the peripheral part of the object to be held, if a convex part is formed around the back surface of the object, contact with the convex part can be avoided and the suction can be carried out. This is to prevent the occurrence of warping due to

〔Example〕

FIG. 1 is a plan view showing a holding device which is an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view thereof.

In this embodiment, this holding device includes a holder 1 formed into a substantially square flat plate shape, and suction ports 2 are arranged concentrically in a square annular groove on the top surface of the holder 1. has been done. A suction path 3 is connected to the groove bottom of the suction port 2, and the suction path 3 is connected to a suitable negative pressure supply means (not shown) such as a vacuum pump.

On the peripheral part of the upper surface of the holder 1, a sloped part 4 as a relief part is formed in an annular shape that is substantially concentric with the suction port 2 so as to be inclined outwardly. The enclosed central portion is a substantially circular plane and forms the suction surface portion 5 .

The area of the suction surface portion 5 is set such that it can reliably hold a glass substrate 6 as an object to be held, which is an original plate of a photomask, without being deformed by suction. The slope portion 4 is formed so as to escape the peripheral portion of the back surface of the glass substrate 6 by an appropriate height.
The slope is set to be as gentle as possible. Note that it is desirable to provide a radius at the shoulder portion where the slope portion 4 and the suction surface portion 5 intersect.

Next, the effect will be explained.

For example, when positioning the glass substrate 6 with respect to the exposure light source when printing a pattern on the glass substrate 6, which is the original plate of a photomask, using an exposure device, the glass substrate 6 whose surface is coated with the resist 7 is placed on the holder 1. They are placed almost concentrically. When the suction port 2 is sucked through the suction path 3, the back surface of the glass substrate 6 is attracted to the upper surface of the holder 1, thereby being fixedly held in the holder 1.

By the way, when the glass substrate 6 is rotated at high speed and a resist solution is dropped on the surface of the glass substrate to apply the resist 7 to the surface of the glass substrate 6, the resist goes around to the periphery of the back surface of the glass substrate 6, and the resist solution is dropped onto the surface of the glass substrate 6. It is conceivable that a convex portion 8 may be formed in the portion.

Then, when the glass substrate 6 on which the resist protrusions 8 are formed on the periphery of the back surface is attracted to the upper surface of the holder 1, the protrusions 8 are sandwiched between the upper surface of the holder 1 and the back surface of the glass substrate 6. Since a gap is formed between the holder 1 and the glass substrate 6 at the center, this gap bone and the glass substrate Fi6
This will cause warping due to suction.

If the mask pattern is printed while the glass substrate 6 is warped, errors will occur in the pattern, which will cause misalignment of multilayer patterns in the manufacture of semiconductor devices.

However, in the holding device having the above configuration, since the slope portion 4 is formed at the peripheral portion of the upper surface of the holder 1, the occurrence of warping of the glass substrate 6 is avoided. That is, since the convex portion 8 formed around the back surface of the glass substrate 6 faces the slope portion 4 of the holder 1, it is spaced apart from the top surface of the holder 1, and there is no space between the glass substrate 6 and the holder 1. The glass substrate 6 is not pinched in the center.
There is no gap between the holder 1 and the holder 1.

Therefore, since the glass substrate 6 is attracted to the suction surface portion 5 in the center of the holder 1 while remaining flat, no warping occurs.

When the glass substrate 6 is attracted to the suction surface section 7 of the holder 1, at the shoulder where the suction surface section 7 and the slope section 4 intersect, there is a boundary between the contact surface with the holder 1 and the non-contact surface on the back surface of the glass substrate 6. Since a line is formed, there is a risk that traces of the boundary line will be imprinted on the back surface of the glass substrate 6 due to the adsorption force. However, since the slope portion 4 has a gentle slope, marking of the boundary line is prevented. If a radius is formed in the shoulder part between the suction surface part 7 and the slope part 4,
Prevention of traces becomes even more reliable.

〔effect〕

(1) By forming an escape part on the periphery of the suction surface of the holder to escape the peripheral part of the object to be held, it is possible to avoid the occurrence of a gap between the object to be held and the holder in the central part. Therefore, it is possible to prevent the object to be held from being warped due to adsorption.

(2) Since it is possible to prevent the object to be held from warping, when printing a mask pattern on a glass substrate in the manufacture of semiconductor devices, it is possible to prevent pattern printing errors and to prevent multilayer patterns from forming. One cause of mismatch between patterns in overlapping exposure can be eliminated.

(3) By configuring the relief part around the object to be held by a slope with a gentle slope, it is possible to attract and hold a part of the back surface of the object to be held. It is possible to prevent suction traces from being imprinted on the back surface.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the escape portion for escaping the periphery of the object to be held is not limited to the slope portion, but may be formed from an annular groove or the like formed in the periphery of the suction surface of the holder.

[Application field]

In the above description, the invention made by the present inventor was mainly applied to the application field for holding a glass substrate that is a photomask original plate, which is the field in which the invention was made by the present inventor, but the invention is not limited thereto. In the manufacture of semiconductor devices, it can also be applied as a holding device for holding wafers.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a holding device which is an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view thereof. 1... Holder, 2... Suction port, 3... Suction path, 4
. . . slope portion, 5 . . . suction surface portion, 6 . . . glass substrate (object to be held), 7 . . . resist, 8 . Agent Patent Attorney Akira Takahashi Mistake 1 Diagram 2 Cause

Claims (1)

[Scope of Claims] 1. A holding device in which a holder that holds a plate-shaped object by suction through a suction port has an escape portion formed on the suction surface of the holder to allow the peripheral portion of the object to escape. 2. The holding device according to claim 1, wherein the relief portion is a slope portion that slopes toward the periphery of the holder. 3. The holding device according to claim 2, wherein the slope of the slope portion is set to be gentle.