JPS61156733A - Apparatus for fixing plate-like object in vacuum - Google Patents

Abstract

PURPOSE:To correct a plate planately by fixing the circle of a plate with a plurality of devices arranged in a plane, outwardly applying a tension to a specific device with a spring in the radial direction of the plate. CONSTITUTION:A reference base 16 is provided oppositly of a reference plate 13 for placing a wafer12 and a device 15 for fixing the wafer with a spring 14, the wafer is nipped and held by a reference plate 17 and a spring 18, and a tension is applied radially of the wafer by a spring 20. when pulled by the spring 20, the reference plate 17 slides on the upper surface of the base 16 along a guard 21. The tension may be on the order of 1kg with a single clamp. With this structure, a large-sized wafer can be placed planarly in vacuum without twisting or warping, thereby enabling high-precision exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sample fixing device in vacuum, and in particular, when fixing a semiconductor wafer with an electron beam exposure device or the like in the manufacturing process of semiconductor devices, electrostatic In the chuck method, the locus of the electron beam fluctuates due to the influence of the electric field, making accurate drawing impossible. Therefore, this method relates to a wafer fixing device that does not have an electric field (and does not distort or twist the wafer).

[Conventional technology]

In recent years, semiconductor wafers have become denser and more highly integrated, and electron beam exposure and X-ray exposure have become practical as patterning methods. It has become necessary to expose semiconductor wafers in a flat and untwisted state, and as semiconductor wafers become larger in size, methods for fixing semiconductor wafers in vacuum become more important.

Conventionally, wafers have been fixed in a vacuum using an electrostatic chuck method or a mechanical method.

FIG. 4 is a sectional view of a conventional mechanical fixing device, in which the wafer fixing table 1 has a positioning pin 3 that comes into contact with the oriented flat (OF) portion of the wafer 2, and the wafer is The surface of the wafer is fixed by the bottle 3 and the presser metal fitting 4, while the wafer fixing table 1 is pushed upward by a spring 5 at the bottom.

Normally, regarding the flatness and twist of a wafer required for electron beam exposure, etc., the limit for warpage is said to be about 10 μm per exposure unit of the wafer, and the limit for the height of twist is 10 μm. In conventional mechanical fixing devices, both the warpage and twist of the wafer are about 30 μm to 40 μm.

Wafers with large warps and twists have disadvantages such as the need to increase the depth of focus during exposure, and also cause pattern distortion and complicated pattern connection.
The drawback was that highly accurate exposure was not possible.

There is also a method of fixing using a magnetic chuck method using an electromagnet, but in the case of electron beam exposure, the electromagnetic field formed by this electromagnet affects the electric field of the electron beam, which causes the trajectory of the electron beam to change. It is impossible to use because it changes.

[Problem that the invention seeks to solve]

In the device for fixing a plate-shaped object in a vacuum with the above configuration, it is simply fixed by applying mechanical pressure to the fixing device.
A problem with large wafers is the occurrence of flatness and distortion, which results in the inability to accurately pattern the semiconductor wafer.

[Means for solving problems]

The present invention provides a device for fixing a plate-like object in a vacuum that solves the above-mentioned problems. The plate-shaped body is fixed in a flat shape by a clamping device, and one of the plurality of clamping devices is provided with a spring that applies tension to the plate-shaped body in a radial direction to flatten the plate-shaped body in a vacuum. This can be achieved by a plate fixation device.

[Effect]

The present invention provides a plurality of clamps arranged in a planar manner around the circumference of a plate-shaped body to prevent warping or twisting of the semiconductor wafer surface when fixing a plate-shaped body such as a semiconductor wafer in a vacuum. It is fixed with a device, and certain clamp devices of the clamp device apply tension outward in the radial direction of the plate-shaped body using a spring or the like to make the plate-shaped body flat without warping or twisting. It is.

〔Example〕

FIG. 1 is a cross-sectional view illustrating a device for fixing a plate-shaped body in a vacuum according to an embodiment of the present invention.

There is a substrate placement table 11, on which a semiconductor wafer 12 is placed as a plate-like body.
There are a reference plate 13 for arranging the wafer, and a clamping device 15 for fixing the wafer using a spring 14.

Opposed to the wafer surface clamping device 15, there is a reference stand 16 serving as a reference surface in the opposite direction, and a clamp device 19 equipped with a reference plate 17 and a spring 18 for clamping the wafer.
A tension spring 20 is provided to apply tension to the inserted wafer in the radial direction.

In the figures, arrows indicate the direction of movement of the spring or clamping device.

FIG. 2 is a plan view from the front side of the wafer, and shows the relative position of the reference plate 17 to which tension is applied with respect to the reference plate 13 placed around the wafer 12. , since the purpose is to arrange the wafer flatly, 4
It is possible to appropriately arrange more than one reference plate.

FIG. 3 shows a cross-sectional view taken along the line X-X in FIG. It is configured to be able to slide, and is designed to constantly apply tension to the wafer.

Since the thickness of the wafer is normally 0.5 mm, the interposition gap may be set to this extent, and the tensile force for a single clamp portion may be approximately 1 kg.

The plate-shaped object fixing device according to the present invention reduces the warpage and twist of the wafer to 10 μm or less, making it possible to perform highly accurate patterning.

〔Effect of the invention〕

As explained above in detail, the present invention makes it possible to place a large semiconductor wafer in a vacuum on a flat plane without twisting or warping, and therefore enables high-precision electron beam exposure, etc. There is a great effect.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view illustrating a device for fixing a plate-shaped body in a vacuum according to an embodiment of the present invention, FIG. 2 is a diagram showing the relative arrangement of a wafer and a reference plate of the present invention, and FIG. FIG. 4 is a sectional view of a conventional mechanical fixing device. In the figure, 11 is a substrate placement table, 12 is a wafer, 13 is a reference plate, 14 is a spring, 15 is an inserting device,
16 is a reference stand, 17 is a reference plate, 18
19 is a spring, 19 is a clamp device, and 20 is a tension spring 21, which is a guard. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A plurality of positions around the plate-shaped body placed in a vacuum are fixed in a plane by a plurality of clamp devices on a fixing table, and tension is applied to the plate-shaped body in the radial direction by one of the plurality of clamp devices. 1. An apparatus for fixing a plate-like object in a vacuum, characterized in that an additional spring is provided to flatten the plate-like object.