JPH0582631A - Vacuum chuck for semiconductor wafer - Google Patents

Abstract

PURPOSE:To chuck a semiconductor wafer with high accuracy by eliminating the influence by dust and by preventing the deformation of the semiconductor wafer. CONSTITUTION:The plurality of suction grooves 4, each having a suction hole 6 on its bottom, are formed concentrically on a suction face 2 and dust adhesion preventing grooves 5 having a width larger than that of the suction groove 4 are concentrically formed on the suction face 2 which are located between the adjacent suction grooves 4 and a vacuum pump 9 is installed for setting the pressure in the suction grooves 4 at a required vacuum pressure through each suction hole 6. By installing a pressure adjustor 12 which adjusts the pressure of the inside of each dust adhesion preventing groove 5 to the required pressure through an air hole made on the bottom of each groove 5, the pressure of the inside of the dust adhesion preventing grooves is made to have such a value that it may not have any influence by suction from the suction grooves or by the width of the dust adhesion preventing grooves.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer vacuum chuck for vacuum-sucking a semiconductor wafer such as a silicon wafer for flatness measurement, lapping or grinding.

[0002]

2. Description of the Related Art Conventionally, a vacuum chuck for semiconductor wafers of this type is shown in FIG. 4, for example, in order to prevent defective adhesion due to the presence of dust between a semiconductor wafer, which is an object to be adsorbed, and an adsorption surface. In addition, a plurality of suction grooves 22 each having a suction hole 21 at the bottom are formed on the suction surface 2 of the chuck body 23.
4 is provided concentrically with each other, and a dust adhesion preventing groove 25 wider than the suction groove 22 is provided on the suction surface 24 between the adjacent suction grooves 22.
And a vacuum pump (not shown) which makes each suction groove 22 have a required vacuum pressure through each suction hole 21.
No. 445), or as shown in FIG. 5, the dust adhesion prevention groove 25 is provided with a leak hole 26 communicating with the atmosphere in the bottom portion of the dust adhesion prevention groove 25 (actual opening 62-). No. 23447).

[0003]

However, in the above-mentioned conventional vacuum chuck for semiconductor wafer, the semiconductor wafer W is provided by providing the dust adhesion preventing groove 25.
Since the adsorption area in contact with the dust is reduced and the dust is trapped in the dust adhesion preventing groove 25, the influence of the dust can be eliminated, but in the case of the one shown in FIG. Alternatively, because of the roughness, the inside of the dust adhesion prevention groove 25 is also vacuum-sucked through the adsorption groove 22, so that the semiconductor wafer W is curved and deformed so as to protrude into the dust adhesion prevention groove 25 as shown in FIG. In the case of the one shown in FIG. 5, the inside of the dust adhesion preventing groove 25 communicates with the atmosphere through the leak hole 26 and becomes a pressure much larger than the inside of the adsorption groove 22. As described above, there is a problem that the portion of the semiconductor wafer W corresponding to the dust adhesion preventing groove 25 is curved and deformed so as to project outward. Therefore, an object of the present invention is to provide a semiconductor wafer vacuum chuck capable of preventing deformation of a semiconductor wafer and chucking the semiconductor wafer with high accuracy while eliminating the influence of dust.

[0004]

In order to solve the above-mentioned problems, a vacuum chuck for semiconductor wafers according to the present invention is provided with a plurality of suction grooves having suction holes at the bottom thereof, which are concentrically formed on the suction surface, and which are adjacent to each other. For semiconductor wafers, in which a dust adhesion prevention groove wider than the suction groove is concentrically provided on the suction surface between the grooves, and a vacuum pump is provided to bring each suction groove to a required vacuum pressure through each suction hole. The vacuum chuck is provided with a pressure adjusting means for adjusting the inside of each of the dust adhesion preventing grooves to a required pressure through a ventilation hole formed in each bottom.

[0005]

In the above means, the suction area in contact with the semiconductor wafer is reduced, and the pressure in the dust adhesion prevention groove is kept at a value that can eliminate the influence of suction from the adsorption groove and the dust adhesion prevention groove width. Be done.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a plan view and a cross-sectional view of a main part of a semiconductor wafer vacuum chuck according to an embodiment of the present invention.

In the figure, reference numeral 1 denotes a disk-shaped chuck body made of metal, ceramics, glass or the like.
Four suction grooves 4 are concentrically provided with the suction hole 3 at the center as the center, and the suction surface 2 between the suction holes 3 and the adjacent suction grooves 4 is wider than the suction grooves 4. The dust adhesion preventing groove 5 is provided concentrically. Suction holes 6 are formed at the bottom of each suction groove 4 along the radius of the chuck body 1, and the suction holes 6 and the suction holes 3 at the center are formed.
Are communicated with each other through a communication hole 7 formed in the chuck body 1. The communication hole 7 is opened on the outer peripheral surface of the chuck body 1 and is connected to a vacuum pump 9 that interposes a pressure adjuster 8 to bring each suction groove 4 to a required vacuum pressure. On the other hand, at the bottom of each dust adhesion preventing groove 5, a ventilation hole 10 forms an angle of about 90 ° with the row of suction holes 6 and the chuck body 1 is formed.
These vent holes 10 are installed along the radius of
Are communicated with each other by a communication hole 11 formed in the chuck body 1. The communication hole 11 is opened on the outer peripheral surface of the chuck body 1, and the atmosphere is supplied so that each dust adhesion preventing groove 5 has a required pressure capable of eliminating the influence of the suction from the suction groove 4 and the width of the dust adhesion preventing groove 5. It is connected to a pressure adjuster 12 as a pressure adjusting means.

In the semiconductor wafer vacuum chuck having the above structure, when chucking the semiconductor wafer W,
Since the adsorption area in contact with the semiconductor wafer W is reduced and the dust is captured by the dust adhesion preventing groove 5, adverse effects such as deformation of the semiconductor wafer W due to the inclusion of dust can be eliminated and the surface to be attracted of the semiconductor wafer W can be eliminated. The pressure in the dust adhesion preventing groove 5 which is reduced due to the vacuum suction in the suction groove 22 due to the unevenness or roughness of the
Is adjusted to the required pressure by the semiconductor wafer W
The deformation of the portion corresponding to the dust adhesion preventing groove 5 can be reduced, and the semiconductor wafer can be chucked with high accuracy.

A vacuum chuck having a suction groove width of 0.5 mm, a distance between the suction grooves of 10 mm, and a dust adhesion prevention groove width of 8 mm is used to insert a silicon wafer having a thickness of 0.6 mm into the suction groove. When chucking at a pressure of -500 mmHg, when the inside of the dust adhesion prevention groove becomes -100 mmHg due to leakage due to roughness or unevenness of the back surface of the silicon wafer, it is calculated that the surface of the silicon wafer is deformed by 0.2 μm at the maximum. Pressure of 0mmHg, -1mmHg and -2mmH by pressure regulator
g, the amount of deformation of the silicon wafer surface is 0.003 μm, as shown by curves A, B and C in FIG.
m, 0.0005 μm and 0.001 μm.

Therefore, the pressure inside the groove for preventing dust adhesion is
It can be understood that the deformation amount of the portion corresponding to the dust adhesion preventing groove of the silicon wafer can be set to be equal to or less than the deformation amount of the portion corresponding to the suction groove by setting it to 1 mmHg. In the embodiment described above, the suction hole 3 is formed in the center of the suction surface 2.
However, the diameter of the innermost suction groove 4 may be reduced and only the dust adhesion preventing groove 5 may be provided inside the suction groove 4.

[0011]

As described above, according to the vacuum chuck for a semiconductor wafer of the present invention, the adsorption area in contact with the semiconductor wafer becomes small, and the dust is trapped in the dust adhesion preventing groove. In addition to eliminating the adverse effects of semiconductor wafer deformation, etc., the pressure inside the dust adhesion prevention groove becomes the required pressure that can eliminate the effects of suction from the adsorption groove and dust adhesion prevention groove width, etc. It is possible to reduce the deformation of the portion of the wafer corresponding to the dust adhesion preventing groove, and it is possible to chuck the semiconductor wafer with high accuracy.

[Brief description of drawings]

FIG. 1 is a plan view of a vacuum chuck for a semiconductor wafer according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a semiconductor wafer vacuum chuck according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of an amount of deformation of a surface of a semiconductor wafer chucked by a semiconductor wafer vacuum chuck according to an embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a conventional semiconductor wafer vacuum chuck.

FIG. 5 is a sectional view of a main part of another conventional semiconductor wafer vacuum chuck.

[Explanation of symbols]

 2 Adsorption surface 4 Adsorption groove 5 Dust adhesion prevention groove 6 Suction hole 9 Vacuum pump 10 Vent hole 12 Pressure regulator

Claims (1)

[Claims] 1. A plurality of suction grooves having suction holes at the bottom are provided concentrically on the suction surface, and dust adhesion prevention grooves wider than the suction grooves are concentrically provided on the suction surface between adjacent suction grooves. And in the semiconductor wafer vacuum chuck provided with a vacuum pump that makes each suction groove a required vacuum pressure through each suction hole, a ventilation hole opened in each bottom of each dust adhesion prevention groove is provided. A vacuum chuck for a semiconductor wafer, which is provided with pressure adjusting means for adjusting the pressure to a required pressure via the vacuum chuck.