JP2001293650A - Manufacturing method of ceramic member for holding wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a wafer holding ceramic member adequate for a conveying/holding member of a semiconductor wafer, an LCD glass substrate, a magnetic disk substrate and the like. SOLUTION: In this manufacturing method of the wafer holding ceramic member, a projection is formed at a predetermined position of a ceramic substrate by a sandblast machining method, and the edge of the tip of the projection is finished like curved surface. The edge of the tip of the projection is polished using a brush holding abrasive grains on the surface or inside the bristles to be finished like curved surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a semiconductor wafer,
The present invention relates to a method for manufacturing a ceramic member for holding a wafer, which is suitable for transporting and holding a liquid crystal display (hereinafter referred to as LCD) glass substrate, a magnetic disk substrate, and the like.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing semiconductors such as LSIs, ceramic members such as alumina, silicon carbide, and aluminum nitride have been used as members for transporting and holding semiconductor wafers. For example, it is desirable that foreign matter, dust, and the like do not adhere to the wafer holding surface of a semiconductor wafer transporting and holding member, but if foreign matter, dust, or the like adheres to this portion, defocus may occur at the time of exposure, or a photoresist, etc. At the time of spin-coating of the coating liquid.

A pin contact method for solving such problems of foreign matter and dust by reducing the contact area of the wafer holding surface is disclosed in Japanese Patent Application Laid-Open Nos. 62-24639 and 2-2294.
No. 42 is proposed. Also, as a method of forming protrusions (pins) on the wafer holding surface, a blast mask is attached to the surface of the base material serving as the wafer holding surface, and exposed and developed to expose the shaved portion of the ceramic base material, and then sand or the like is exposed. A sand blasting method in which only the exposed portion is scraped off by spraying the abrasive material and only the portion where the blast mask is attached is left as a projection is disclosed in JP-A-62-24639, JP-A-62-221130, and the like. I have.

However, the sand blasting method described above has a disadvantage that the area of the blast mask cannot be reduced so much, and the area of the tip of the projection (wafer holding surface) in contact with the wafer increases. Was. That is, usually after attaching the blast mask,
Exposure, curing, and development expose the part to be removed, but if the area of the blast mask to be left (the part that becomes a protrusion) is small, the size and shape of the blast mask will vary during development, This is because the blast mask melts and disappears. Even if a blast mask having a small area can be formed, the blast mask is peeled off during sandblasting, and a part of the projection is not formed or chipping easily occurs. Furthermore, since the tips of the projections after the sandblasting are angular, the wafer surface is damaged, and foreign matter, dust, and the like easily adhere to the edge.

[0005] To solve the above-mentioned drawbacks, Japanese Patent Application Laid-Open No. 9-2836
No. 05, etc., a method in which a nylon brush is rotated to round the periphery of the protruding portion, or as shown in JP-A-8-139169, a protruding portion is formed on a ceramic substrate surface by a sandblasting method. After that, a diamond,
A method in which abrasive grains such as alumina are mixed with oil (lard), and this is applied to a brush made of heat-resistant nylon, piano wire, etc., and the brush is rotated to polish the protrusions on the surface of the ceramic base material and round the periphery of the tip. Has been proposed.

However, simply rotating the nylon brush described above only wears the nylon brush and has no polishing effect, and it is difficult to round the periphery of the tip of the projection.

[0007] On the other hand, in the method of rotating the brush after applying a mixture of the abrasive grains and the oil to the brush, the abrasive speed is extremely low because the abrasive grains are released from the brush. Variations in the amount tend to occur, and the polishing process requires a very long time, and a mixture of abrasive grains and oil must be added frequently, which increases the cost.

[0008]

SUMMARY OF THE INVENTION The present invention relates to the transfer of semiconductor wafers, LCD glass substrates, magnetic disk substrates, and the like.
An object of the present invention is to provide a method of manufacturing a ceramic member for holding a wafer suitable for a holding member or the like.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a projection is formed at a predetermined position on a ceramic substrate by a sandblasting method, and an edge portion at the tip of the projection is finished into a curved surface to form a ceramic member for holding a wafer. A method of manufacturing a ceramic member for holding a wafer, characterized in that an edge portion of a tip of a projection is polished with a brush holding abrasive grains on the surface and inside of a bristle portion to finish it into a curved surface. .

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The material of the ceramic substrate used in the present invention is not particularly limited as long as there is no problem in mechanical properties such as rigidity, abrasion resistance and hardness. For example, alumina, zirconia, cordierite, etc. And non-oxide ceramics such as silicon carbide, silicon nitride, and aluminum nitride.

As a method of forming the projections by the sand blasting method, for example, a blast mask is attached to the surface of a flat ceramic base material, and the blast mask is patterned into a required shape by exposure, curing, and development. There is a method in which after exposing the portion to be shaved, only the exposed portion is shaved with a sand blasting machine, and the remaining portion, specifically, the portion to which the blast mask is adhered is used as a projection.
In the above description, the blast mask has been described as an example in which the blast mask is attached to the surface of the ceramic substrate and then patterned. However, the blast mask may be attached to the surface of the ceramic substrate after patterning.

The blast mask used to form the projections is preferably a sheet made of a UV-sensitive resin such as urethane or acrylic. The diameter of the protrusion tip is preferably in the range of 0.2 to 1 mm, more preferably in the range of 0.22 to 0.8 mm. The height is preferably in the range of 30 to 200 μm, and more preferably in the range of 50 to 150 μm. In the present invention, it is preferable that the surface of the ceramic base material before the blast mask is applied is flattened by grinding, lapping, or the like so that the flatness is 5 μm or less. The flatness can be measured using an optical flat.

There is no particular limitation on the abrasive grains used for sandblasting. For example, abrasive grains having an average particle size of about 10 to 250 μm, such as silicon carbide and alumina, can be used. This abrasive for sand blasting is 100
By spraying the surface of the ceramic base material with a pressure of ~ 500 KPa, the portion where the blast mask is attached is not cut off and remains as it is, and the other portions are cut to a certain depth, and the protrusions having a desired shape and height ( Pins) can be formed. The shape of the projection is preferably a conical shape, a cylindrical shape, a quadrangular prism shape, a quadrangular pyramid shape, or the like.

The edge portion at the tip of the projection can be formed into a curved surface by polishing using a brush holding abrasive grains on the surface and inside of the bristle portion. The material of the abrasive grains is not particularly limited, but it is preferable to use diamond, alumina, zirconia, silicon carbide, or the like. Regarding the size of the abrasive grains, it is preferable to use small abrasive grains having a diameter in the range of 1 to 500 μm because the diameter of the projections of the ceramic base material is small.

There is no particular limitation on the material of the brush hair, but a resin-based material that can easily hold abrasive grains, such as nylon,
It is preferable to use vinyl chloride or the like. The hair diameter is
The range is preferably 0.1 to 2 mm, and the length is 5 mm.
A range of １００100 mm is preferred.

As a method of holding the abrasive grains, after mixing the liquid resin and the abrasive grains, the surface of the hair and the inside of the hair can be mixed and held by a method such as injection or extrusion. The holding amount (content) of the abrasive grains is preferably in the range of 5 to 50% by volume based on the hair.

In order to polish the edge of the tip of the projection using a brush having abrasive particles held on the surface and inside of the bristle portion to finish it into a curved surface, for example, the brush rotates, revolves, reciprocates, swings It is preferable that the polishing is performed by a combination of the above-described movement and the movement of the ceramic substrate as the workpiece, such as rotation, revolving, reciprocating movement, and swinging. 100 for brush rotation
The range of min3000 min ⁻¹ is preferred. The rotation speed of the ceramic substrate as the workpiece is 5 to 300 min ^-1.
Is preferable. It is to be noted that polishing with a brush as in the present invention is preferably performed in a wet manner, and is preferably performed using, for example, a water-soluble polishing liquid or various grinding liquids.

The shape of the tip of the projecting portion may be any shape as long as it has no edge portion and a curved surface.
It is preferably in the range of 0 μm, and more preferably in the range of 10 to 30 μm. R can be measured using a surface roughness / limb shape measuring device manufactured by Tokyo Seimitsu Co., Ltd.

[0019]

The present invention will be described below with reference to examples.

Example 1 After laminating a sheet-shaped ultraviolet-sensitive resin (Fuji Base Film, manufactured by Fuji Manufacturing Co., Ltd.) on the surface of a ceramic substrate having a flatness of 5 μm, a diameter of 200 mm and a thickness of 10 mm Then, a predetermined positive film is placed thereon, exposed to ultraviolet light from above, exposed only to cure the exposed portion, and then developed to remove the ultraviolet-sensitive resin in the unexposed portion of the ultraviolet light. Then, an ultraviolet-sensitive resin patterned in a desired shape was adhered to obtain a ceramic substrate having a partially exposed surface.

Next, using a sand blasting machine, the exposed portion of the ceramic substrate was exposed to silicon carbide abrasive grains having an average particle size of 60 μm at a pressure of 300 KPa, a lateral movement speed of 0.01 m / sec, and a vertical movement speed of 0.01 m / sec. The moving speed is sprayed 15 times at a speed of 0.05 m / sec, then the ultraviolet-sensitive resin is peeled off, and the protrusion 2 having the edge 1 at the tip as shown in FIG.
200 were formed. The diameter of the tip of the obtained protrusion 2 is in the range of 0.22 to 0.26 mm, and the height of the protrusion 2 is 9 mm.
It was 0 μm.

Thereafter, the ceramic base material 3 on which the projections 2 are formed is mounted on a work turntable 6 arranged on a work turntable support 5 of the polishing apparatus shown in FIG.
After fixing, the work rotating table 6 is rotated counterclockwise at a rotation speed of 50 min ^-1 , and the tip of the bristles 9 of the brush 8 attached to the tip of the brush fixing arm 7 is attached to the tip of the projection 2 of the ceramic base material 3. The brush 8 is rotated clockwise at a rotation speed of 1000 min ^-1 for 2 minutes each while supplying the polishing liquid from the upper portion of the brush 8 for 2 minutes, and then reversely rotated at the same rotation speed for 2 minutes, respectively. For 4 minutes, the edge 1 at the tip of the projection 2 of the ceramic base 3 was polished to obtain a ceramic base 3 finished in a curved shape as shown in FIG. In FIG. 2, reference numeral 10 denotes a polishing liquid supply tank, and reference numeral 11 denotes a supply nozzle.

The brush 8 used above is made of heat-resistant nylon bristles having a diameter of 0.55 mm and a length of 30 mm.
At a rate of 200 pieces per cm ² , a total of 120,000 pieces were used. In addition, a diamond abrasive having an average particle diameter of 5 μm was held on the heat-resistant nylon bristles by an extrusion method at a ratio of 10% by volume to the heat-resistant nylon. In FIG. 3, reference numeral 4 denotes a curved portion. In addition, when the shape was measured at arbitrary 20 places of the curved surface portion 4, it was in the range of R20 to 30 μm.

Next, the tip of the protrusion is polished by lapping so that the diameter is in the range of 0.16 to 0.20 mm.
Further, a through hole for vacuum suction and the like were formed to obtain a ceramic member for holding a wafer.

Comparative Example 1 Using a heat-resistant nylon brush which does not hold abrasive grains,
A ceramic substrate polished was obtained through the same steps as in Example 1 except that the work rotating table and the brush were polished clockwise and counterclockwise alternately for 2 minutes each for a long period of 24 hours in total. After the polishing process, any 2
Observation of the shape at 0 places revealed no evidence of a curved surface.

Comparative Example 2 A mixture of diamond abrasive grains having an average particle size of 5 μm and lard was attached to a heat-resistant nylon brush at a rate of 0.1 g / cm ³ with respect to the heat-resistant nylon, and a work rotating table and Example 1 except that the brush was polished clockwise and counterclockwise alternately for 2 minutes each for as long as 24 hours in total.
Through the same steps as above, a polished ceramic substrate was obtained. The mixture of diamond abrasive grains and lard used above had to be supplied 48 times during the polishing process because the mixture was severely released from the heat-resistant nylon brush. After the polishing treatment, the shape was measured at arbitrary 20 places at the tip of the protrusion, and it was found that only a curved surface of R2 to 5 μm was formed.

[0027]

The ceramic member for holding a wafer obtained by the method of the present invention is a ceramic member for holding a wafer, which is suitable for transferring and holding semiconductor wafers, LCD glass substrates, magnetic disk substrates and the like.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view showing a protrusion formed on a ceramic base material.

FIG. 2 is a perspective view showing a polishing apparatus.

FIG. 3 is a partially enlarged view showing a state in which an edge portion at the tip of a protrusion is rounded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Edge part 2 Projection part 3 Ceramic base material 4 Curved surface part 5 Rotary table support base 6 Rotary table 7 Brush fixing arm 8 Brush 9 Bristle 10 Polishing liquid supply tank 11 Supply nozzle

Claims (1)

[Claims] 1. A method of manufacturing a ceramic member for holding a wafer by forming a projection at a predetermined position on a ceramic base material by a sandblasting method, and finishing an edge portion of the tip of the projection into a curved surface. A method for producing a ceramic member for holding a wafer, characterized in that the edge portion of (1) is polished with a brush having abrasive grains held on the surface and inside of the bristle portion to finish it into a curved surface.