JPH1110472A - Vacuum suction holding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To flatten a holding surface with high accuracy by taking one main surface of a porous ceramic plate as a holding surface, coating the peripheral edge part of the holding surface and the side of the porous ceramic plate with a sealing material such as resin, glass or the like to be air-tightly sealed, and making the sealing material coated on the peripheral edge part of the holding surface conductive. SOLUTION: As a sealing material 5, conductive resin or glass is applied to the side of a porous ceramic body 2 and stepped parts 2b, 2d of upper and lower one main surfaces and impregnated in such a manner as to fill up pores of the porous ceramic body 2. Further, coating is performed to fill up the stepped parts 2b, 2d of the upper and lower one main surfaces to be air-tightly sealed. Thus, the top of the sealing material 5 coated on the stepped part 2b and an adsorption surface are flattened to form the same flat surface to be taken as a holding surface 6 for a workpiece W. The workpiece W is placed on the holding surface 6 of a vacuum suction holding device 1, and vacuum- sucked from a sucking surface 4 by a vacuum pump to suck and hold the work piece W with good accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum suction holding device in which a holding portion of a holding surface is made of a porous ceramic, and more particularly to cutting a workpiece such as a semiconductor wafer or a substrate for a thin film magnetic head with a blade. It is suitable for dicing or slicing for separation.

[0002]

2. Description of the Related Art Conventionally, in the process of cutting and separating a workpiece such as a semiconductor wafer or a substrate for a magnetic head in a manufacturing process of a semiconductor device or a thin film magnetic head, a vacuum suction holding device for suctioning and holding the workpiece. Is used.

[0003] This type of vacuum suction holding device includes a device in which a suction portion of a holding surface is made of a porous ceramic body and a device in which a number of suction holes are formed in a dense ceramic plate. In the cutting / separating step, a porous type capable of obtaining a uniform adsorption force is often used.

FIG. 4 shows a general porous type vacuum suction holding device 21 in which a recess 25 opened at the center of a base 24 made of metal such as stainless steel has a diameter slightly smaller than the workpiece W. The workpiece W is held by fitting the porous ceramic body 22 and using the upper surface thereof as the suction surface 23 and positioning the suction surface 23 on the same plane as the top surface 28 of the rim 27 of the base 24. The surface 29 was formed. Then, the workpiece W placed on the holding surface 29 is sucked and fixed by vacuum suction through an exhaust hole 26 communicating with the concave portion 25 of the base 24, and the diamond blade 30 is fixed to the top of the rim 27. After making minute contact with the surface 28 and electrically detecting the contact to make the cutting start state, the diamond blade 30 is moved horizontally along the holding surface 29 or the vacuum suction holding device 21 is moved. The workpiece W is cut and separated into a predetermined shape by moving the workpiece W horizontally.

[0005]

However, in the case of a two-body structure in which the porous ceramic body 22 is fitted into the concave portion 25 of the base 24 as in the vacuum suction holding device 21 of FIG. 4, the base 24 made of metal is used. When the workpiece W is cut, the holding surface 29 of the vacuum suction holding device 21 is delicate due to the heat generated by friction with the diamond blade 30 because the difference in thermal expansion between the workpiece and the porous ceramic body 22 is large. There was a problem that it was deformed. For this reason, a large number of products cannot be cut out from a single substrate such as a semiconductor wafer or a substrate for a thin-film magnetic head according to predetermined dimensions, and productivity cannot be increased.

Further, since the suction surface 23 forming the holding surface 29 and the top surface 28 of the rim portion 27 are made of different materials, it is difficult to grind them so as to form the same plane.

That is, since the stainless steel forming the rim portion 27 has a lower hardness than the ceramics forming the suction surface 23, the top surface 28 of the rim portion 27 is cut more than the suction surface 23 when the surface is ground. There is a problem that a step is formed. Therefore, when a semiconductor wafer or a substrate for a thin-film magnetic head is cut as the workpiece W, the peripheral edge of the workpiece W is not held by the top surface 28 of the rim portion 27, so that the peripheral edge of the workpiece W It was not possible to cut out a product having a predetermined size.

In addition, in the case of a two-body structure as in the vacuum suction holding device 21 of FIG. 4, the porous ceramic body 22 and the base 24 constituting the suction surface 23 must be formed separately. In order to increase the number of points and flatten the adsorption surface 23 and the top surface 28 of the rim portion 27 on the same plane as described above, the dimensional accuracy of the porous ceramic body 22 and the base 24 must be strictly adjusted. There were also inconveniences such as having to manage.

[0009]

SUMMARY OF THE INVENTION In view of the above problems, a vacuum suction holding apparatus according to the present invention uses one main surface of a porous ceramic plate as a holding surface, and a peripheral portion of the holding surface and a porous ceramic plate. A sealing material such as resin or glass is applied to the side surface to seal airtightly, and at least a sealing material applied to a peripheral portion of the holding surface has conductivity. .

[0010]

The vacuum suction holding device according to the present invention has an integral structure in which a sealing material such as resin or glass is applied to the side surface of the porous ceramic plate and the peripheral portion of the suction surface. As described above, deformation of the holding surface due to processing heat generated at the time of cutting can be suppressed. In addition, the holding surface of the workpiece including the suction surface can be finished flat, and the sealing material is impregnated so as to fill the pores of the porous ceramic plate. Can be.

Furthermore, since the sealing material applied to at least the peripheral portion of the holding surface is made conductive, it is possible to electrically detect the minute contact of the diamond blade with the holding surface, and The workpiece can be cut without damaging the workpiece.

[0012]

Embodiments of the present invention will be described below.

FIG. 1 is a view showing an example of a vacuum suction holding apparatus 1 according to the present invention, in which (a) is a perspective view and (b) is XX of (a).
2 is an enlarged sectional view of a portion A in FIG. 1B.

The vacuum suction holding apparatus shown in FIG. 1 is a disk-shaped porous ceramic plate 2 having an outer diameter larger than the workpiece W.
The stepped portion 2b having a depth h of about 50 to 500 μm is provided at a peripheral portion of one main surface of the porous ceramic plate 2, and the surface of the central convex portion 2a is used as the suction surface 3 while the other main surface is formed. Is also provided with a step 2d having a depth h of about 50 to 500 μm at the peripheral edge thereof, and the surface of the central convex portion 2c is used as the suction surface 4. The outer shape of the suction surface 3 is formed to be equal to or slightly smaller than the workpiece W.

On the side surface of the porous ceramic body 2 and the step portions 2b and 2d of the upper and lower main surfaces, a conductive resin or glass as the sealing material 5 is provided.
Of the sealing material 5 applied to the stepped portion 2b and airtightly sealed so as to fill the stepped portions 2b and 2d of the upper and lower main surfaces. The suction surface 3 is flattened so as to form the same plane, and is used as a holding surface 6 for the workpiece W.

For this reason, if the workpiece W is placed on the holding surface 6 of the vacuum suction holding device 1 and vacuum-suctioned from the suction surface 4 by a vacuum pump (not shown), the workpiece W can be uniformly sucked. Thus, the workpiece W can be sucked and held, and the work piece W can be suction-held accurately with the flat holding surface 6 having no step.

In order to cut and separate the workpiece W fixed to the holding surface 6, first, the diamond blade 30 is brought into contact with the sealing material 5 applied to the peripheral portion of the holding surface 6 to start cutting. And

That is, as shown in FIG. 1B, if one of the power supplies is connected to the diamond blade 30 and the other is connected to the sealing material 5 applied to the vacuum suction holding device 1,
Since the sealing material 5 has conductivity, conduction can be achieved by bringing the diamond blade 30 into contact with the sealing material 5, and the diamond blade 30 is held by vacuum suction by measuring the flowing current with an ammeter. It is possible to confirm that the cutting surface has started to be in a state of minute contact with the holding surface 6 of the device 1.

Thus, the workpiece W can be cut and separated into a predetermined shape by moving the diamond blade 30 in the horizontal direction or by moving the vacuum suction holding device 1 in the horizontal direction.

The vacuum suction holding device 1 shown in FIG.
Since it is an integral structure made of the porous ceramic body 2, the holding surface 6 of the workpiece W can be a flat surface with no steps, and the deformation of the holding surface 6 due to processing heat generated during cutting can be suppressed. Since the workpiece W can be cut to a predetermined dimensional accuracy, for example, a large number of products are cut out from a single substrate such as a semiconductor wafer or a substrate for a thin film magnetic head, and each product is cut out. Even when the workpiece W that requires high dimensional accuracy is cut, all products can be cut out according to predetermined dimensions, and productivity can be greatly increased.

Further, since a resin or glass having conductivity is applied as a sealing material 5 to the side surface of the porous ceramic body 2 and the peripheral portion of the holding surface 6 and the airtight sealing is performed.
By vacuum suction from the suction surface 4, the workpiece W can be suction-held on the suction surface 3 with a desired suction force, and the diamond blade 30 is applied to the sealing material 5 applied to the peripheral edge of the holding surface 6. , Contact can be reliably established, so that the minute contact can be electrically detected, and the workpiece W can be detected without damaging the holding surface 6.
Can be cut and separated.

By the way, as the porous ceramic body 2 constituting the vacuum suction holding apparatus 1 having such an integrated structure,
In order to suppress deformation of the holding surface 6, a material having a rigidity (Young's modulus) of 8000 kg / mm ² or more is preferable. For example, ceramics such as alumina, zirconia, silicon nitride, silicon carbide, and aluminum nitride can be used.

In order to hold the workpiece W with a uniform suction force, the average pore diameter of the porous ceramic body 2 is 5 to 50 μm.
m and a porosity of 5 to 40% are preferred, and more preferably an average pore diameter of 5 to 10 μm and a porosity of 25 to 3
5% is good. This is because if the average pore diameter of the porous ceramic body 2 is less than 5 μm,
This is because even if the suction force is increased, a large suction force cannot be obtained because the gas flow resistance of the gas passing through the inside is too large. Conversely, if the average pore diameter is larger than 50 μm, the thin workpiece W This causes the pores to be recessed when suction is performed, thereby impairing the flatness accuracy of the workpiece W and making it impossible to cut the workpiece W to a predetermined dimensional accuracy.

The porosity of the porous ceramic body 2 is 5
If it is less than 1, the number of open pores communicating the suction surface 3 and the suction surface 4 is small, so that a uniform suction force cannot be obtained.
If it exceeds 0%, the rigidity of the porous ceramic plate 2 is greatly reduced, and the holding surface 6 may be deformed.

As the porous ceramic plate 2 of the present invention, granules obtained by granulating various raw materials are formed into a predetermined shape by a generally known ceramic forming means such as a uniaxial pressing method or an isopressing method. After that, it is only necessary to use porous ceramics obtained by firing at a temperature slightly lower than the temperature at which various raw materials can be completely sintered, and by appropriately adjusting the particle diameter of the granules and the firing temperature, a predetermined amount can be obtained. Average pore diameter and porosity. In addition, ceramic spheres made of various raw materials are formed in advance, and porous ceramics in which these are bonded with an adhesive component such as glass, or those obtained by bonding spherical ceramic calcined bodies with a binder or the like are used. It is also possible to use porous ceramics formed by sintering the contact portions of each ceramic calcined body by firing, and by using such porous ceramics, it is possible to reduce the particle diameter of ceramic spherical bodies and ceramic calcined bodies. By adjusting, it is possible to easily set a predetermined average pore diameter and a predetermined porosity, and it is possible to obtain a more uniform adsorption force.

On the other hand, as the sealing material 5 for hermetically sealing the periphery of the porous ceramic body 2, a material obtained by mixing a conductivity imparting agent with various resins or glass may be used.

For example, as the resin having conductivity, acrylic resin, epoxy resin, silicon resin, urethane resin, phenol resin, or the like can be used as the resin material. As the conductivity imparting agent, gold (Au) can be used. ), Silver (Ag), copper (C
u), a metal such as nickel (Ni) may be used. These conductivity-imparting agents are uniformly mixed and dispersed at a ratio of 60 to 90% by weight, preferably 80 to 85% by weight with respect to the resin material, so that the volume resistivity of the resin is 10 Ω · cm or less. Can be. For this reason, since a very small current can be passed, it is possible to reliably detect that the diamond blade 30 has minutely contacted.

The conductive glass may be L
Crystallization in which one or more of Fe ₂ O ₃ , Ni ₂ O ₃ , and Cu ₂ O are added to an i ₂ O—Al ₂ O ₃ —SiO ₂ system glass as a conductivity imparting agent and the surface resistance is less than 10 ³ Ω. It consists of glass or Na ₂ O-WO ₃ -P ₂ O ₅ system glass or Na ₂ O-WO ₃ -B ₂ O ₅ system glass, and has a surface resistance of Na _0.7 WO ₃ crystal deposited on the surface layer. 1Ω
Some degree of crystallized glass or the like can be used.

Also, since these sealing materials 5 can be made into a paste, they can be applied to the porous ceramic plate 2 and then cured, so that the pores can be appropriately impregnated, and the anchor effect can be obtained. Reliable adhesion strength is obtained, and airtight sealing can be achieved.

If the thickness of the sealing material 5 is too small, it is difficult to reliably close the pores existing on the outer surface of the porous ceramic body 2, and there is a possibility that the sealing cannot be performed airtightly. The thickness of the thinnest portion of the sealing material 5 including the portion impregnated in 2 is preferably 7 μm or more, more preferably 10 μm or more.

In this embodiment, the suction surface has a circular outer shape. However, the suction surface may be appropriately designed according to the shape of the workpiece W. For example, an elliptical or polygonal shape may be used. Or a star-shaped thing may be used.

Incidentally, the vacuum suction holding device 1 shown in FIG.
In the above, an example is shown in which both the side surface of the porous setum plate 2 and the peripheral edge of the holding surface 6 are hermetically sealed with a sealing material 5 having conductivity. In the present invention, at least the peripheral edge of the holding surface 6 is formed. It is sufficient that the sealing material 5 has conductivity. For example, the above-mentioned resin or glass containing no conductivity-imparting agent, or other well-known resin or glass is applied to the side surface of the porous setumic plate 2. At the same time, a structure in which the resin or glass containing a conductivity-imparting agent is applied to the sealing material 5 constituting the peripheral portion of the holding surface 6 may be employed.

In the vacuum suction holding device 1 shown in FIG. 1, a stepped portion 2b,
Although the example in which the 2d is provided is shown, as in the vacuum suction holding device 11 shown in FIG. 3, no step is provided on the upper and lower main surfaces of the porous ceramic plate 12, and the porous ceramic plate 12 except the suction surface 13 and the suction surface 14 is provided. The sealing material 15 may be sufficiently impregnated so as to fill the pores in the periphery of the porous ceramic plate 12. With such a structure, the holding surface 16 of the workpiece W can be further flattened. Further, the processing accuracy of the workpiece W can be improved.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the vacuum suction holding apparatus 1 shown in FIG.

First, in order to form the porous ceramic plate 2 of the vacuum suction holding device 1, Al ₂ O ₃
99% by weight of powder, SiO ₂ , M
gO was added and mixed together with a binder and a solvent in a total range of 1% by weight, and granulated by a spray drier to produce granules. Then, the granules are filled in a mold and formed into a disk shape, taken out of the mold, and fired at a temperature of about 1700 ° C. to form a porous material made of alumina ceramic having a porosity of 30% and an average pore diameter of 10 μm. A ceramic plate 2 was formed.

Next, the periphery of the upper and lower main surfaces of the porous ceramic plate 2 is subjected to grinding to form a stepped portion 2 of about 200 μm.
b, 2d are formed, and the top surface of the upper central convex portion 2a is polished to form the suction surface 3, and the top surface of the lower central convex portion 2c is polished to form the suction surface. 4 was formed. Then, silver (Ag) is added as a conductivity imparting agent to 80
The acrylic resin slurry mixed and dispersed by weight% is mixed with the side surface of the porous ceramic plate 2 and the step portion 2 of the upper and lower main surfaces.
After being applied to b and 2d, it is cured and hermetically sealed with a sealing material 5 having conductivity. Thereafter, the upper main surface is polished to form the holding surface 6 of the workpiece W. Thus, the vacuum suction holding device 1 shown in FIG. 1 was formed.

Then, when a product having a size of 50 × 50 mm is cut out from an 8-inch silicon wafer using the vacuum suction holding device 1, all products can be cut out. When the dimensions were measured, the dimensional error could be suppressed to ± 0.005 mm.

[0038]

As described above, according to the vacuum suction holding device of the present invention, one main surface of the porous ceramic plate is used as the holding surface, and the peripheral portion of the holding surface and the side surface of the porous ceramic plate are coated with resin or the like. A sealing material such as glass is applied and airtightly sealed, and at least the sealing material applied to the periphery of the holding surface is made conductive to flatten the holding surface with high precision. The workpiece can be accurately held with a uniform suction force. In addition, in the process of cutting the workpiece with the diamond blade, if the diamond blade is brought into contact with the sealing material forming the peripheral portion of the holding surface, conduction can be reliably achieved, so that the minute contact has been achieved. Electrical detection can be performed, and the workpiece can be cut and separated without damaging the holding surface.

In addition, since it is an integral structure made of a porous ceramic body, deformation of the holding surface due to processing heat generated at the time of cutting can be greatly suppressed, and the number of components in the structure can be reduced, and Since the production is easy, the production cost can be greatly reduced.

Thus, if the vacuum suction holding apparatus of the present invention is used for dicing or slicing of a semiconductor wafer or a substrate for a thin-film magnetic head, all products can be cut and separated to predetermined dimensions, and productivity can be reduced. Can be enhanced.

[Brief description of the drawings]

FIG. 1A is a perspective view showing an embodiment of the vacuum suction holding device of the present invention, and FIG. 1B is a cross-sectional view taken along line XX of FIG.

FIG. 2 is an enlarged sectional view of a portion A in FIG. 1 (b).

FIG. 3 is a cross-sectional view showing another embodiment of the vacuum suction holding device of the present invention.

FIG. 4 is a sectional view showing a conventional vacuum suction holding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum adsorption holding apparatus 2 ... Porous ceramic plate 2a ... Convex part 2b ... Step part 2c ... Convex part 2d ... Step part 3 ... Adsorption surface 4 ... Suction surface 5: Sealing material 6: Holding surface W: Workpiece

Claims (1)

[Claims] 1. A main surface of a porous ceramic plate is used as a holding surface, and a sealing material such as resin or glass is applied to a peripheral portion of the holding surface and a side surface of the porous ceramic plate to seal airtightly. And a sealing material applied to at least a peripheral portion of the holding surface has conductivity.