JPH0847835A - Suction plate of vacuum chuck - Google Patents

Abstract

PURPOSE:To provide the suction plate of a vacuum chuck which is formed out of a porous body, and can improve flatness of the suction plate forming suction face by cutting. CONSTITUTION:This suction plate 1 is formed out of porous sintered resin trifluoride manufactured from resin trifluoride grain material of mean grain diameter 100mum, and a non-ventilating layer 2 is formed on the outer circumferential part of the suction plate 1 by suckingly injecting silicone rubber. The length of the non-ventilating layer 2 in the diametral direction of the suction plate 1 is set about 100mum. Young's modulus of the silicone rubber is about 1/100 of Young's modulus of sintered resin trifluoride. The suction face side of the suction plate 1 is flatly cut so as to form a suction face 1a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum chuck suction plate.

[0002]

2. Description of the Related Art Conventionally, as a suction plate for a vacuum chuck, there is known a suction plate having a plate-shaped porous body having a large number of through holes communicating with both front and back surfaces. Then, by sucking air from one surface of the suction plate, an object to be sucked such as a silicon wafer is sucked to the other surface. Examples of the material of this porous body include copper, aluminum,
Stainless steel, fluororesin, etc. are used. And
The adsorption plate is formed of a porous body obtained by compression molding and heat sintering fine particles of these materials. As shown in FIG. 3, such a suction plate 21 is fitted to a chuck plate 22, and the chuck plate 22 is attached to the chuck body 2.
Fixed to 3. At this time, there are two methods for sealing the outer peripheral portion of the suction plate 21 as follows.

For example, as shown in FIG. 3, a suction plate 21 made of sintered copper, sintered aluminum, sintered stainless steel or the like has a concave portion of a chuck plate 22 having a columnar concave portion formed on one surface side. Housed within. The chuck plate 22 is made of, for example, copper, aluminum, stainless steel, or the like.
The outer peripheral surface of the suction plate 21 of this type is sealed by the inner peripheral surface of the recess of the chuck plate 22. In this state, the suction surface side of the suction plate 21 is cut by the milling cutter together with the chuck plate 22 to form the suction surface 21a. That is, the suction plate 2
1 is cut along with the suction surface side of the chuck plate 22 so that both surfaces are flush with each other.

Further, as shown in FIG. 5, the suction plate 24 made of sintered fluororesin is fixed to one side of the chuck plate 25 formed in a disc shape. This type of suction plate 2
A non-breathable layer 24 </ b> A is formed on the outer peripheral portion of 5 by applying a synthetic resin such as an epoxy resin to the entire outer peripheral surface or by injecting the synthetic resin into the outer peripheral portion of the chuck plate 24. Then, the non-air-permeable layer 24A seals the outer peripheral surface of the adsorption plate 24, and the inner peripheral portion is formed as an adsorption portion 24B that adsorbs. In this state, the suction surface side of the suction plate 24 is flattened to form a suction surface 24a.

[0005]

However, when the suction surface side of the former suction plate 21 is flatly cut, the heights of the surfaces formed by cutting the suction plate 21 and the chuck plate 22 may be different from each other. there were. Similarly, when the suction surface side of the latter suction plate 24 is flat-cut, the suction portion 24
The height of the surface formed by cutting each of B and the non-air-permeable layer 24A may be different. That is, in the case of the former suction plate 21, as shown in FIGS.
The suction surface 21a of the chuck plate 22 protrudes from the suction surface side of the chuck plate 22. Conversely, the suction surface side of the chuck plate 22 protrudes from the suction surface 21a of the suction plate 21. In the case of the latter suction plate 24, the non-venting layer 24A has the suction portion 24B.
Jump out more. This is because the suction plate 21 and the chuck plate 2
2 or the difference in Young's modulus and hardness between the suction portion 24B and the non-venting layer 24A is caused by addition of cutting conditions such as cutting speed and cutting depth. As a result, the suction plate 2
High flatness was not obtained for the suction surfaces 21a and 24a of Nos. 1 and 24.

When the vacuum chuck provided with the suction plates 21 and 24 is used, for example, in a rotary head of a spin coater for spin-coating a silicon wafer with a photoresist in a semiconductor integrated circuit manufacturing process, or a chuck device of a CVD apparatus / sputtering apparatus. , The wafer is not attracted when it is flat. As a result, the thickness of the thin film formed on the wafer becomes uneven. Therefore, variations in semiconductor integrated circuits manufactured from this wafer are large. Similarly, when a thin film is formed on a glass substrate of a liquid crystal display (LCD), a uniform film thickness cannot be obtained.

Further, the Young's modulus is different between the adsorbing portion 24B formed only of the sintered fluororesin having a low Young's modulus and the non-venting layer 24A formed by injecting an epoxy resin having a high Young's modulus. Therefore, temporarily, the suction surface 24 of the suction plate 24
Even if a high flatness is obtained in a, when a thin silicon wafer is adsorbed, the adsorbing portion 24B and the non-venting layer 24A have different deformation amounts, so that the silicon wafer is deformed.

Alternatively, when performing precision typesetting on a silicon wafer or a glass substrate, an accurate focus cannot be obtained unless the wafer or the like is flatly fixed by suction, thereby causing variations in manufactured products. Further, even when the wafer / glass substrate on the suction plate is heated, a uniform temperature distribution cannot be obtained, so that a thin film having a uniform thickness cannot be formed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to improve the flatness of a suction surface of a suction plate formed of a porous material and having a suction surface formed by cutting. It is an object of the present invention to provide a vacuum chuck suction plate that can be used.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to an outer peripheral portion of an adsorbing plate formed of a porous body having a large number of through holes communicating with both front and back surfaces. A non-breathable layer is formed by injecting a sealing material into the air to block the flow of air, and the suction plate of the vacuum chuck suctions air from one surface of the suction plate to suction the object to be suctioned on the other surface. The Young's modulus of the sealing material was set to be sufficiently smaller than the Young's modulus of the porous body so that the Young's modulus of the non-ventilated layer formed was substantially equal to the Young's modulus of the porous body.

According to a second aspect of the present invention, in the suction plate of the vacuum chuck according to the first aspect, the porous body is formed of sintered fluororesin, and the sealing material is silicon resin. According to a third aspect of the invention, in the suction plate of the vacuum chuck according to the first aspect, the porous body is made of sintered metal and the sealing material is epoxy resin.

[0012]

According to the first aspect of the invention, the Young's modulus of the non-breathable layer formed on the outer peripheral portion of the suction plate becomes substantially equal to the Young's modulus of the porous body forming the suction plate. That is,
The Young's modulus of the formed non-breathable layer becomes substantially equal to the Young's modulus of the part other than the non-breathable layer of the suction plate. As a result, the deviations of the cutting surfaces actually formed in the non-permeable layer and the portion other than the non-permeable layer become substantially equal to the surface of the suction plate through which the blade passes during cutting.

According to the second aspect of the present invention, in addition to the operation of the first aspect, the adsorbing plate is formed of a sintered fluororesin having a low hardness. Things are held flexibly.

According to the invention described in claim 3, in addition to the function of the invention described in claim 1, since the rigidity of the suction part is high, the deformation of the suction plate due to the suction of the suctioned part is prevented. It

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention is shown in FIG.
2 will be described. The suction plate 1 is formed as follows. A prototype of an adsorption plate 1 made of a sintered trifluoride resin as a porous body by filling a molding die with a trifluoride resin particle material having an average particle diameter of about 100 μm, and compression-molding and heat-sintering. To mold. This prototype is cut into a predetermined shape to form the suction plate 1. In this embodiment, the average diameter of the through holes formed inside the porous body is approximately 100 μm, and the porosity is 42%. The Young's modulus of the sintered trifluoride resin is approximately 40 kg / mm ² .

Next, the non-venting layer 2 is formed on the outer peripheral portion of the adsorption plate 1. First, as shown in FIG. 2, the suction plate 1 is housed in a housing hole 3 a formed in the center of a disc-shaped casting jig 3. At this time, the lower surface of the suction plate 1 is brought into close contact with the bottom of the accommodation hole 3a. Further, the shielding plate 4 is fixed to the upper surface of the suction plate 1 in close contact. Next, the silicone resin 5 is injected between the accommodation hole 3a and the suction plate 1, and air is sucked from the suction port 3b formed at the bottom of the accommodation hole 3a. By this suction, the silicone resin 5 is injected into the outer peripheral portion of the suction plate 1. In this example, the silicone resin 5 was injected into the outer peripheral portion to form the non-venting layer 2 having a length of 100 μm in the radial direction of the adsorption plate 1. Therefore, the portion of the suction plate 1 other than the non-air-permeable layer 2 becomes the suction portion 6 through which air flows between the front and back. The Young's modulus of the silicon resin is almost 1/100 that of the sintered trifluoride resin. This suction plate was bonded and fixed to the upper surface of the chuck plate 7 formed in a disk shape with aluminum.

After the suction plate 1 is completely fixed to the chuck plate 7, the suction surface side of the suction plate 1 is cut by a milling cutter to form a suction surface 1a. Cutting includes rough cutting, medium cutting, and finish cutting. First, in rough cutting, the suction surface side of the suction plate 1 is cut several times with a cut amount of approximately 10 μm. By this rough cutting, relatively large irregularities on the suction surface side are removed. In medium cutting, cutting is performed several times while gradually reducing the cutting depth. In medium cutting, the size of the burr generated in the through hole portion on the cutting surface becomes gradually smaller. Finally, as a final cutting, the cutting is performed with a cutting amount of approximately 1 μm. By the finish cutting, the suction surface 1a is finally formed. As a result of measuring the flatness of the suction surface 1a formed as described above, the protrusion amount of the non-breathable layer 2 from the suction portion 6 could be set to 0 to 0.2 μm. Heretofore, a non-venting layer 2 is formed by injecting an epoxy resin into the outer peripheral portion of the adsorption plate 1 of the sintered trifluoride resin formed by the same manufacturing method as in the present embodiment, and the same plane cutting as in the present embodiment The amount of protrusion of the non-breathable layer 2 from the suction portion 6 on the formed suction surface 1a was 2 to 10 μm.

As described above, in the present embodiment, the adsorption plate 1 is formed of sintered trifluoride resin, and the non-venting layer 2 is formed of a Young's modulus approximately one hundredth of the Young's modulus of the sintered trifluoride resin. Formed by injecting a silicon resin 5 having The increase in the Young's modulus of the non-breathable layer 2 formed by the injection of the silicon resin 5 with respect to the adsorption portion 6 was set to be negligible.
That is, the Young's modulus of the non-ventilated layer 2 of the suction plate 1 and the Young's modulus of the suction portion 6 were made substantially equal. As a result, the level difference between the non-air-permeable layer 2 and the suction portion 6 on the suction surface 1a formed by plane cutting can be set to 0 to 0.2 μm, which is significantly smaller than the conventional level. Therefore, the flatness of the suction surface 1a can be significantly increased as compared with the conventional case.

Further, since the Young's modulus of the suction portion 6 of the suction plate 1 and that of the non-breathable layer 2 are substantially equal, even when a thin work such as a silicon wafer is suctioned, the flatness of the suction surface 1a is not lost. .

It should be noted that the present invention is not limited to the above-described embodiment, but may be configured as follows. (1) The porous material forming the adsorption plate 1 is not limited to the sintered trifluoride resin, but may be a sintered body of synthetic resin such as tetrafluororesin, nylon resin, polyacetal resin, or the like. Further, instead of the silicone resin, a nitrile rubber having a Young's modulus of about 1/100 of the synthetic resin may be used.

(2) The porous body forming the suction plate 1 may be made of a metal material such as sintered copper, sintered aluminum, and sintered stainless steel. In this case, as the sealing material, for example,
It is possible to use a synthetic resin such as an epoxy resin or a phenol resin whose Young's modulus is almost 1/100 of that of the porous body of the metal material. That is, a material having a higher Young's modulus than silicon resin can be used.

(2) The average particle diameter of the trifluoride resin and the average diameter of the through holes may be changed appropriately. (3) The radial length of the suction plate 1 of the non-venting layer 2 to be formed may be changed appropriately.

(4) Instead of injecting the silicone resin 5 into the outer peripheral portion of the suction plate 1 by suction, the silicone resin 5 may be injected by natural permeation to form the non-venting layer 2. In this specification, means and members according to the configuration of the present invention are:
It shall be defined as follows.

(1) The through hole means a space formed in the material forming the suction plate and allowing the air to flow between the front and back surfaces of the suction plate by connecting these spaces to each other. (2) The sealing material is a non-venting material that is injected into the outer peripheral portion of the adsorption plate formed of a porous body having a large number of through holes for allowing air to flow therethrough and blocks air circulation between both sides of the outer peripheral portion. It means a material forming a layer, and is not limited to thermosetting resins such as epoxy resin and phenol resin, but also includes elastomers such as silicon resin and nitrile rubber.

[0025]

As described above in detail, according to the invention described in claim 1, the flatness of the suction surface of the suction plate formed of the porous body and having the suction surface formed by cutting is improved. be able to.

According to the second aspect of the present invention, in addition to the above effects, it is possible to prevent damage due to the adsorption of the object to be adsorbed. According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, it is possible to adsorb the object without deforming it.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a suction plate according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a state in which a silicone resin is injected into the outer peripheral portion of the suction plate by suction.

FIG. 3 is a cross-sectional view showing a conventional suction plate.

FIG. 4 is likewise a sectional view of a suction plate.

FIG. 5 is likewise a sectional view of the suction plate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Adsorption plate, 2 ... Non-venting layer, 5 ... Silicon resin as sealing material.

Claims (3)

[Claims] 1. A sealing material (5) is injected into an outer peripheral portion of an adsorption plate (1) formed of a porous body having a large number of through holes communicating with both front and back surfaces to block air flow. A suction plate of a vacuum chuck which forms a ventilation layer (2) and sucks air from one surface of the suction plate (1) to suck an object to be suctioned on the other surface. Rate of the formed non-breathable layer (2)
The suction plate of a vacuum chuck having a Young's modulus sufficiently smaller than the Young's modulus of the porous body so that the Young's modulus of the porous body becomes substantially equal to the Young's modulus of the porous body. 2. The vacuum chuck suction plate according to claim 1, wherein the porous body is formed of a sintered fluororesin, and the sealing material (5) is used.
Is a vacuum chuck suction plate made of silicon resin. 3. The vacuum chuck suction plate according to claim 1, wherein the porous body is made of a sintered metal and the sealing material (5) is an epoxy resin.