JP6159987B2 - Vacuum adsorption apparatus and method for manufacturing the same - Google Patents

Description

  The present invention relates to a vacuum suction apparatus for sucking and holding a processing substrate and a method for manufacturing the same.

  Conventionally, when a substrate such as a semiconductor wafer is transported, processed, or inspected, a vacuum suction device using a vacuum pressure has been used. Since such a vacuum suction device is required to have uniform suction, a device that holds the entire surface of the substrate by suction with a porous material has been studied.

  For example, a vacuum suction device has been proposed in which a placing portion made of a porous body is joined to a support portion and a base with an adhesive such as resin or glass (see Patent Document 1). In such a vacuum suction device, the support part is made of non-porous material and surrounds the outer periphery of the mounting part, and the base is a dense body. And it forms so that a board | substrate can be fixed to the adsorption | suction surface of a mounting part by carrying out vacuum suction from the lower suction hole.

  However, when a wafer or the like is fixed to the suction portion using such a porous body and grinding / polishing is performed, polishing dust accumulates on the suction surface of the mounting portion. For this reason, the grinding scrap accumulated on the suction surface weakens the suction force for attracting the wafer, and during suction, the wafer is deformed in the direction perpendicular to the suction surface, so that the flatness can be maintained with high accuracy. Sometimes it disappeared.

  Therefore, if the grinding scraps accumulated on the suction surface of the mounting part increase, the suction surface is polished to remove the clogged portion of the grinding scraps, and the newly exposed surface is used as the suction surface. The clogging is eliminated.

JP-A-53-090871

  As described above, the clogging of the grinding scraps has been eliminated by polishing the adsorption surface, but when the adsorption surface of the mounting portion is polished, the ceramic particles are likely to be degranulated on the exposed surface.

  The placing portion made of the porous ceramic is configured by bonding ceramic particles and glass particles, and segregation of glass occurs when the porous body is manufactured. Thereby, the bonding force of the ceramic particles is weakened, and the particles are shed. Such degranulation can damage thin substrates when the device is used.

  For such segregation of glass, it is conceivable to reduce the particle size of ceramic particles, increase the surface area of the particles, and increase the amount of glass particles filled in the gaps. This can improve the binding force of the particles, but it does not provide a drastic measure against degranulation.

  The present invention has been made in view of such circumstances, and a vacuum suction device that suppresses degranulation when the suction surface of the mounting portion is polished and enables grinding of the substrate with high accuracy, and its manufacture. It aims to provide a method.

  (1) In order to achieve the above object, the vacuum suction device of the present invention is a vacuum suction device for sucking and holding a processing substrate, has a mounting surface for holding and sucking the substrate, and is 60 μm or less. Present in a mass ratio of 0.15 to 0.45 with respect to the first skeleton particles and the first skeleton particles, and having an average particle diameter of 1/5 or less with respect to the first skeleton particles. It is formed as a ceramic porous body by being bonded to the second skeleton particles by a binding material, and there is substantially no gap between the mounting portion having a Rockwell hardness of 80 HRH or more and the mounting portion described above. It is characterized by comprising a ceramic dense body formed by firing, and a support portion having intake holes communicating with the pores of the mounting portion.

  As described above, in the vacuum adsorption device of the present invention, since the mounting portion is composed of two particle sizes of the first skeleton particles and the second skeleton particles, the second skeleton particles are contained in the pores of the first skeleton particles. Is mixed in to reduce the pore diameter and porosity. Further, the binding force and the rigidity of the binding material are increased by the anchor effect between the second skeleton particles and the binding material. With such a configuration, the Rockwell hardness of the mounting portion is improved, and degranulation when the adsorption surface is polished is suppressed. As a result, it is possible to suppress degranulation when the adsorption surface of the mounting portion is polished and to grind the substrate with high accuracy.

  (2) Further, in the vacuum adsorption device of the present invention, the first skeletal particles have a particle size D95 at which the cumulative number from the small particle size side becomes 95% of the total number of particles is not more than twice the average particle size. It has a particle size distribution. Thus, since the particle size of D95 is twice or less than the particle size of D50, the anchor effect by adding fine particles functions effectively.

  (3) Moreover, the vacuum adsorption device of the present invention is characterized in that the binder is present in a mass ratio of 0.1 to 0.2 with respect to the first skeleton particles. Thereby, the binding force and strength of the binding material are increased by the anchor effect of the second skeleton particles and the binding material.

  (4) Moreover, the vacuum suction device of the present invention is characterized in that the mounting portion has a bending strength of 55 MPa or more. Thereby, degranulation when the adsorption surface is polished can be suppressed.

(5) Moreover, as for the vacuum adsorption apparatus of this invention, the said description part is that the number of degranulation is 10 or less per 1 / cm < ² > in the peel test using the acrylic tape of adhesive strength 2.74N / cm. It is a feature. Thereby, the detachment of the mounting surface when the substrate is vacuum-sucked is suppressed, and the substrate can be ground with high accuracy.

  (6) Moreover, the vacuum suction apparatus of the present invention is characterized in that the placement section has a porosity of 25% or more and 45% or less. Thereby, the high intensity | strength which does not generate | occur | produce a degranulation can be obtained, maintaining a sufficient adsorption function.

  (7) Moreover, the vacuum suction apparatus of the present invention is characterized in that the mounting portion has a pore diameter of 15 μm or less in terms of median diameter. Thus, since the pore diameter is small, the strength of the placement portion can be improved.

  (8) Moreover, the vacuum suction device of the present invention is characterized in that the joint portion between the mounting portion and the support portion has a strength higher than the strength of the mounting portion alone. Thereby, since a gap does not occur in the joining portion, it is possible to prevent the mounting portion from being deformed by pressing of the grindstone even when the substrate is ground or polished. As a result, stable processing accuracy of the substrate can be obtained.

  (9) Moreover, the manufacturing method of the vacuum adsorption device of the present invention is the above-described manufacturing method of the vacuum adsorption device, wherein the first skeleton particles, the second skeleton particles, the first skeleton particles, and the second A slurry preparing step of combining a skeletal particle and mixing a binder particle having an average particle size of 1/10 or less with respect to the aggregate of the first skeleton particle and the second skeleton particle to prepare a slurry; A slurry filling step of filling the ceramic dense body having the slurry produced in the above step, and a firing step of firing at a temperature equal to or higher than the softening point of the binder particles together with a molded body formed by the slurry filled in the recess. It is characterized by including. Thereby, it can prevent that a clearance gap arises between a mounting part and a recessed part, can improve the intensity | strength of a mounting part, and can manufacture the vacuum suction apparatus with which it is hard to produce a degranulation in a mounting part.

  ADVANTAGE OF THE INVENTION According to this invention, the degranulation when the adsorption | suction surface of a mounting part is grind | polished is suppressed and the grinding | polishing of a board | substrate with high precision is enabled.

It is sectional drawing which shows schematic structure of the vacuum suction apparatus which concerns on this invention. (A), (b) It is a schematic diagram which shows the cross section of the porous body which mix | blended each single particle | grain porous body and particle size.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, the vacuum suction device of the present invention is simply referred to as a “vacuum suction device”.

[Configuration of vacuum suction device]
FIG. 1 is a cross-sectional view showing a schematic configuration of the vacuum suction device 1. The vacuum suction device 2 sucks and holds a processing substrate as an object to be sucked 6 when grinding a semiconductor wafer, a glass substrate for liquid crystal, or the like. As shown in FIG. 1, the vacuum suction device 1 includes a placement portion 2, a support portion 3, and an intake hole 4.

  The mounting portion 2 is formed of a porous body made of glass and one kind of ceramic selected from alumina, silicon nitride, silicon carbide, and zirconia, and has a mounting surface 2a for holding and adsorbing the object 6 to be adsorbed. doing. The pores of the mounting portion 2 made of a porous body communicate with each other. In addition, it is preferable that the mounting part 2 is formed of a porous body made of alumina and glass, or silicon carbide and glass. Moreover, the material of the mounting part 2 and the material of the support part 3 need to be the same in order for these joining surfaces to be integrally fired substantially without a gap.

  The placement portion 2 is formed as a porous body in which the first skeleton particles and the second skeleton particles are bonded together by a binder. The first skeleton particles have an average particle size of 60 μm or less. The second skeleton particles are present in a mass ratio of 0.15 or more and 0.45 or less with respect to the first skeleton particles, and have an average particle diameter of 1/5 or less with respect to the first skeleton particles.

  By having such a configuration, the second skeleton particles are mixed in the pores of the first skeleton particles, and the pore diameter and the porosity are reduced. In addition, due to the anchor effect between the second skeleton particles and the binding material, the binding force of the binding material and the strength of the mounting portion 2 are increased.

  The first skeletal particles preferably have a particle size distribution in which the cumulative number from the small particle size side is 95% of the total number of particles and the particle size D95 is not more than twice the average particle size. Thus, since the particle size of D95 is twice or less than the particle size of D50, the anchor effect by adding fine particles functions effectively.

  The binder is present in a mass ratio of 0.1 to 0.2 with respect to the first skeleton particles, and has an average particle diameter of 1/10 or less with respect to the aggregate of the first skeleton particles and the second skeleton particles. preferable. Thereby, the binding force of the binding material and the strength of the placement portion 2 are increased by the anchor effect of the second skeleton particles and the binding material.

  FIGS. 2A and 2B are schematic views showing cross sections of a single-particle porous body and a porous body in which particle sizes are mixed, respectively. As shown in FIG. 2 (a), a ceramic porous body composed of a single particle having the first skeleton particles 11 and the binder 12 (the particle diameter of the skeleton particles is single) has a binding force of the binder. And the strength of the porous body is lowered.

  On the other hand, as shown in FIG. 2B, when the second skeleton particles 13 are mixed in the pores of the first skeleton particles 11, the pore diameter and the porosity can be reduced. Further, due to the anchor effect with the glass powder to be the binder 12, the binding force of the binder and the strength of the porous body are increased, and a ceramic porous body having high strength can be manufactured.

  Since the mounting portion 2 is configured as such a porous body, it has a Rockwell hardness of 80 HRH or more and a bending strength of 55 MPa or more. As a result, degranulation when the adsorption surface is polished can be suppressed. Further, the grain removal when the adsorption surface of the mounting portion 2 is polished is suppressed, and the substrate can be ground with high accuracy.

  The placement unit 2 preferably has a porosity of 25% or more and 45% or less. Thereby, the high intensity | strength which does not generate | occur | produce a degranulation can be obtained, maintaining a sufficient adsorption function. Moreover, it is preferable that the mounting part 2 has a pore diameter of 15 μm or less in terms of median diameter. Thus, the strength of the mounting portion 2 can be improved by having a fine pore diameter.

Moreover, it is preferable that the mounting part 2 has 10 or less per 1 / cm < ² > in the number of shed particles in a peel test using an acrylic tape having an adhesive strength of 2.74 N / cm. Thereby, the detachment of the mounting surface 2 when the substrate is vacuum-sucked is suppressed, and the substrate can be ground with high accuracy.

  The placement surface 2a is an adsorption surface, and is formed by polishing together with the placement portion 2 and the support portion 3 around the placement portion. For example, a substrate such as a semiconductor wafer is placed on the placement surface 2a as the object to be adsorbed 6 and is used for adsorbing the substrate.

  The support part 3 surrounds and supports the outer edge of the mounting part 2 by the concave part 3a, and is made of one type of dense body of ceramics selected from alumina, silicon nitride, silicon carbide, and zirconia. As in the case of the mounting portion 2, among the above, it is preferably formed of alumina or silicon carbide. The joint interface between the placing portion 2 and the support portion 3 is baked integrally with substantially no gap.

The above-mentioned “fired integrally with substantially no gap” means that the porous body structure of the mounting portion is continuous up to the interface in contact with the supporting portion, and the mounting portion and the supporting portion are supported. This means that there is no gap at the joint interface with the part, and the placing part and the support part are integrally fired.

  It is preferable that the joint part of the mounting part 2 and the support part 3 has the intensity | strength more than the intensity | strength of a mounting part single-piece | unit. Thereby, since a gap does not occur in the joint portion, it is possible to prevent sinking deformation of the mounting portion 2 due to the pressing of the grindstone even during grinding / polishing of the adsorbent 6. As a result, stable processing accuracy to the adsorbent 6 is obtained.

  The support portion 3 has an intake hole 4 that communicates with the pores of the placement portion 2. The suction hole 4 has a hole shape provided so as to penetrate the support part 3 in the center part on the back side of the mounting part, and is sucked by a vacuum pump (not shown) through the suction hole 4. A semiconductor wafer or the like that is the object to be adsorbed 6 placed on the placement surface 2 a of the placement unit 2 can be vacuum-sucked to the placement unit 2. The gap 5 is provided over the entire back surface of the placement unit 2, and is provided for suction across the entire surface of the placement unit 2.

[Method of manufacturing vacuum suction device]
Next, a manufacturing method of the vacuum suction device 1 configured as described above will be described. First, water or alcohol is added to the first skeleton particles, the second skeleton particles, and the binder particles that bind the first skeleton particles and the second skeleton particles, which are the raw material powder of the porous body that forms the mounting portion 2. Add and mix to prepare slurry.

  As the first skeleton particles and the second skeleton particles, particles such as alumina or silicon carbide can be used. The first skeleton particles are those having an average particle diameter of 60 μm or less, and the second skeleton particles are those having an average particle diameter of 1/5 or less of the first skeleton particles. The formulation is determined so that the mass ratio is 0.15 to 0.45 with respect to the particles. The first skeletal particles preferably have a particle size distribution in which the particle size D95 at which the cumulative number from the small particle size side becomes 95% of the total particle number is not more than twice the average particle size.

  Glass or the like can be used as the binder. The binder particles are present in a mass ratio of 0.1 to 0.2 with respect to the first skeleton particles, and have an average particle size of 1/10 or less with respect to the aggregate of the first skeleton particles and the second skeleton particles. Is preferred. For mixing the raw materials, a known method such as a ball mill or a mixer can be applied. In consideration of the particle size of the ceramic powder and the addition amount of the glass powder, the addition amount of water or alcohol is adjusted so as to obtain a desired fluidity.

  Next, a ceramic support portion 3 made of alumina, zirconia, silicon carbide or silicon nitride provided with a recess is prepared. Then, the obtained slurry is filled in the concave portion of the support portion 3. At this time, vacuum defoaming for removing residual bubbles and vibration for enhancing filling are applied as necessary. In addition, the air intake holes 4 and the air gaps 5 are closed by a burned-out member such as wax or resin before pouring the slurry mixture to be the placement unit 2.

  Next, after the support portion in which the concave portion 3a is filled with the slurry is sufficiently dried to form the slurry, it is fired at a temperature equal to or higher than the softening point of the glass. At this time, if the firing temperature is lower than the softening point of the glass, sufficient integration cannot be achieved. On the other hand, if the firing temperature is too high, deformation or shrinkage occurs. In this manner, a vacuum suction device that prevents a gap from being formed between the mounting portion 2 and the recess 3a of the support portion 3, can improve the strength of the mounting portion 2, and is less likely to cause degranulation in the mounting portion 2. 1 can be manufactured.

[Example]
Examples of the present invention will be described below. In accordance with the above manufacturing method, a mounting portion was produced. The characteristics of the first skeleton particles, the second skeleton particles, and the binder particles at that time are as shown in Table 1 below. In addition, each addition amount of a 1st frame particle and a 2nd frame particle means the ratio of the sum total of both. Moreover, the addition amount of the binder particles means a ratio when the total addition amount of the first skeleton particles and the second skeleton particles is 1 (hereinafter the same).

When the mounting part was produced under the conditions shown in Table 1, the results shown in Table 2 below were obtained.

As shown in Table 2, the Rockwell hardness of each example was 80 HRH or more, and the strength of the mounting portion was 55 MPa or more. The porosity was 25% or more and 45% or less, and the pore diameter was 15 μm or less. The bonding strength between the mounting portion and the support portion was greater than the strength of the mounting portion alone. The number of shed grains was 10 / cm ² / piece or less.

  The average particle size of the first skeleton particles is 40 μm, the addition amount is 0.75 parts by weight, the particle size distribution of D95 is 72, the average particle size of the second skeleton particles is 8.0 μm, and the addition amount is 0.25 weight. When the average particle size of the binder particles was 2.5 μm and the addition amount was 0.15 parts by weight, the Rockwell hardness was particularly high.

[Comparative example]
Below, a comparative example is also demonstrated. Table 3 shows the manufacturing conditions of the mounting portion, and Table 4 shows the results after manufacturing.

In Comparative Example 1, since the first skeleton particles were 60 μm or more, the pore diameter was 15 μm or more. As a result, the Rockwell hardness became smaller than 80 HRH, and the number of shed grains exceeded 10. In Comparative Example 2, the particle diameter D95 at which the cumulative number from the small particle diameter side of the first skeletal particles was 95% of the total particle number was more than twice the average particle diameter, and the Rockwell hardness was less than 80 HRH. In Comparative Example 3, since the average particle diameter of the second skeleton particles was 1/5 or more of the average particle diameter of the first skeleton particles, the pore diameter was 15 μm or more. As a result, the Rockwell hardness was smaller than 80 HRH, the strength of the mounting portion was smaller than 55 MPa, and the number of shed grains was more than 10 / cm ² / piece.

In Comparative Example 4, since the amount of the second skeleton particles added was 0.15 or less, the pore diameter was 15 μm or more. As a result, the Rockwell hardness was smaller than 80 HRH, the strength of the mounting portion was smaller than 55 MPa, and the number of shed grains was more than 10 / cm ² / piece. In Comparative Example 5, since the added amount of the second skeleton particles was 0.45 parts by weight or more, the pore diameter was 15 μm or more. As a result, the Rockwell hardness became smaller than 80 HRH, and the strength of the mounting portion became smaller than 55 MPa. Further, the bonding strength between the mounting portion and the supporting portion was smaller than the strength of the mounting portion alone, and the number of shed grains was more than 10 / cm ² / piece.

In Comparative Example 6, since the average particle diameter of the binder particles was 1/10 or more of the average particle diameter of the first skeleton particles, shrinkage occurred during heat treatment, and cracks occurred in the porous body. In Comparative Example 7, since the amount of the binder particles added was 0.1 or less, the binding force of the particles was reduced, and the porosity was 45% or more. As a result, the Rockwell hardness became smaller than 80 HRH, and the strength of the mounting portion became smaller than 55 MPa. Further, the bonding strength between the mounting portion and the support portion is smaller than the strength of the mounting portion alone. The number of threshing was more than 10 / cm ² / piece. In Comparative Example 8, since the amount of binder particles added was 0.22 or more, shrinkage occurred during heat treatment, and cracks occurred in the porous body.

DESCRIPTION OF SYMBOLS 1 Vacuum suction apparatus 2 Mounting part 2a Mounting surface 3 Support part 3a Recessed part 4 Intake hole 5 Cavity 6 Adsorbed object (substrate)
11 First skeletal particle 12 Binder 13 Second skeletal particle

Claims (8)

A vacuum suction device for sucking and holding a processing substrate,
A first skeletal particle having a mounting surface for holding and adsorbing a substrate and having an average particle diameter of 60 μm or less and the first skeletal particle in a mass ratio of 0.15 to 0.45; A mounting portion that is formed as a ceramic porous body by binding a second skeletal particle having an average particle diameter of 1/5 or less to one skeletal particle by a binder, and having a Rockwell hardness of 80 HRH or more; ,
A support part having a suction hole that is formed of a ceramic dense body formed by integral firing with substantially no gap between the placement part and communicating with the pores of the placement part. Vacuum suction device.   2. The first skeletal particles have a particle size distribution in which a particle size D95 in which the cumulative number from the small particle size side becomes 95% of the total number of particles is not more than twice the average particle size. Vacuum suction device.   3. The vacuum adsorption device according to claim 1, wherein the binder is present in a mass ratio of 0.1 to 0.2 with respect to the first skeleton particles. 4.   The vacuum suction device according to any one of claims 1 to 3, wherein the placement portion has a bending strength of 55 MPa or more.   5. The placement unit according to any one of claims 1 to 4, wherein the number of shed particles is 10 or less per 1 / cm <2> in a peel test using an acrylic tape having an adhesive strength of 2.74 N / cm. The vacuum suction apparatus described.   The vacuum suction device according to any one of claims 1 to 5, wherein the placing portion has a porosity of 25% or more and 45% or less.   The vacuum suction device according to any one of claims 1 to 6, wherein the placement unit has a median diameter of 15 µm or less.   The vacuum suction device according to any one of claims 1 to 5, wherein a joint portion between the mounting portion and the support portion has a strength higher than that of the single mounting portion.

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