JP6946076B2 - Vacuum suction member - Google Patents

Description

The present invention relates to a vacuum suction member used for sucking and holding a substrate such as a semiconductor substrate or a glass substrate for a liquid crystal display.

In semiconductor manufacturing equipment such as an exposure machine, for uniform adsorption of a substrate such as a semiconductor wafer, for example, a mounting portion made of a porous member is joined to a support portion made of a dense member with an adhesive such as resin or glass. A vacuum suction member composed of the above has been proposed (see, for example, Patent Document 1). According to the vacuum suction member, a vacuum suction force is applied to the substrate mounted on the mounting portion through the intake hole and the mounting portion formed in the support portion. The porous member has a network structure in which ceramic particles (for example, alumina particles) are connected by glass.

Japanese Unexamined Patent Publication No. 2005-205507

However, when the substrate is mounted on the mounting portion, the particles constituting the porous member may be desorbed due to the rubbing between the substrate and the mounting portion, and the desorbed particles may reduce the flatness of the substrate. .. In addition, the desorbed particles may cause scars on the surface of the substrate, which may deteriorate the yield of the product derived from the substrate.

Therefore, the present invention is to provide a vacuum suction member capable of suppressing desorption of particles constituting the porous member.

The vacuum suction member of the first aspect of the present invention is a vacuum suction member that includes a porous member and sucks and holds a substrate, and includes a coating film that covers the upper surface of the porous member, and the porosity of the coating film is the above. It is characterized in that it is smaller than the porosity of the porous member, and at least a part of the vacuum path formed by the communication of the open pores of the porous member is maintained without being blocked by the coating film.

The vacuum suction member of the second aspect of the present invention has an upper surface and a back surface, and is composed of a recess recessed in the direction from the upper surface to the back surface and a through hole provided from the back surface to the bottom surface of the recess. A dense member having a communication path, and a porous member accommodated in the recess of the dense member, having an upper surface and a back surface, and having a predetermined porosity, and adsorbing a substrate. A vacuum suction member for holding, the upper surface of the porous member is provided with a coating having a lower porosity than the porous member, and the open pores of the porous member or the porous member and the said. It is characterized in that communication between the front surface of the coating film and the back surface of the porous member of the secondary vacuum path formed by the open pores existing in the coating film is maintained.

According to the vacuum suction member of the present invention, when the substrate is placed on the vacuum suction member, the surface of the coating becomes the mounting surface of the substrate, and the porous member is removed from the substrate by the coating having a lower porosity than the porous member. Since it is protected, the falling off of the particles constituting the porous member is surely suppressed. Further, even if the upper surface of the porous member is provided with a coating film, the vacuum path (primary vacuum path) formed by communicating the open pores of the porous member is not blocked, and the surface of the coating film and the porous member are not blocked. Since the communication of the vacuum path (secondary vacuum path) with the back surface of the quality member is maintained, the air permeability is not impaired, so that the substrate placed on the upper surface of the vacuum suction member is surely vacuumed. It is adsorbed and held.

In the vacuum suction member of the present invention, it is preferable that at least a part of the porous member is composed of ceramic particles, and the coating film is a ceramic sprayed film.

According to the vacuum suction member having this structure, the adhesion between the porous member whose at least a part is composed of ceramic particles and the coating film which is a ceramic sprayed film is improved, and the firmness of the coating film is improved.

In the vacuum suction member of the present invention, the porosity of the coating film is preferably 1% or more and 20% or less.

According to the vacuum suction member having this configuration, the denseness of the coating film is designed within an appropriate range from the viewpoint of protecting the porous member.

In the vacuum suction member of the present invention, the coating film is preferably a conductive film.

According to the vacuum suction member having this configuration, even if static electricity is generated due to friction between the substrate and the coating film, the electric charge can move within the range where the coating film is continuous, and the accumulation of the electric charge is prevented. Therefore, the situation in which the electrostatic attraction hinders the separation between the substrate and the mounting portion is avoided, and the electrostatic destruction of the substrate or the product derived from the substrate is avoided.

Explanatory drawing which shows a part of the vacuum suction member as one Embodiment of this invention in the cross section. The explanatory view about the coating film formed on the upper surface of the porous member of the vacuum suction member as one Embodiment of this invention.

(First Embodiment)
(composition)
FIG. 1 shows a part of a vacuum suction member 3 as an embodiment of the present invention in cross section, and the vacuum suction member 3 includes a dense member 1, a porous member 2, and a coating film 22. There is.

The dense member 1 is composed of a ceramic sintered body selected from alumina, silicon nitride, silicon carbide and zirconia having a substantially flat plate shape (for example, a disk shape). The dense member 1 has a top surface 4 and a back surface 5, and is provided with a substantially circular recess 12 that is recessed from the top surface 4 toward the bottom surface 5 and a bottom surface 13 of the recess 12 from the bottom surface 5. A communication path 10 having an opening at the center of the bottom surface 13 of the recess 12 is formed, which is composed of a through hole. The bottom surface 13 of the recess 12 may be formed in a concave spherical shape so as to gradually decrease from the peripheral edge portion toward the central portion.

The porous member 2 is a substantially disk-shaped member including a front surface 6 and a back surface 7 and a side surface 8 between the front surface 6 and the back surface 7, and is a sintered body of alumina, alumina, and glass, or a sintered body of alumina, alumina, and glass. , Silicon carbide and glass sintered body. The pores of the porous member 2 communicate with each other between the front surface 6 and the back surface 7 to form open pores and form a secondary vacuum path. For example, the average pore diameter becomes 10 to 150 μm, and the porosity. Is designed to be 20-40%. Alumina powder or silicon carbide powder having an average particle diameter of 30 to 150 μm may be used as a raw material for the porous member 2. The porous member 2 is housed in the recess 12 of the dense member 1, and the side surface 8 is joined to the dense member 1 over the entire circumference while the back surface 7 is generally separated from the bottom surface 13 of the recess 12. Has been done.

The dense member 1 and the porous member 2 are joined in a state where glass or a bonding agent derived from glass and ceramics is interposed between the recess 12 of the dense member 1 and the porous member 2. The dense member 1 and the porous member 2 may be joined by the joining layer derived from the joining agent by fitting the porous member 2 into the recess 12 of the above and subjecting it to heat treatment.

The bottom surface 13 and the side surface of the recess 12 of the dense member 1 and the space defined by the back surface 7 of the porous member 2 form the primary vacuum path R1. The vacuum path is composed of a communication path 10, a primary vacuum path R1 and a secondary vacuum path R2.

A groove communicating with the communication path 10 (for example, a radial groove or a combination of a radial groove and a concentric groove) may be formed on the bottom surface 13 of the recess 12. Further, a part of the back surface 7 of the dense member 1 (a portion that does not correspond to the groove) may be joined to the bottom surface 13 of the recess 12. As the bonding agent, glass or a bonding agent derived from glass and ceramics may be used.

The production of the vacuum suction member 3 as an embodiment of the present invention is performed as follows. First, a dense member 1 made of a sintered body made of alumina or the like is prepared.
The recess 12 of the dense member 1 is filled with a slurry prepared by adding water or alcohol to alumina powder and glass powder, which are raw material powders of the porous member 2, or silicon carbide powder and glass powder. NS. Of the communication path 10 and the recess 12, the portion constituting the primary vacuum path R1 is previously closed or filled with a vanishing member such as resin.

After the slurry filled in the recess 12 of the dense member 1 is sufficiently dried, it is fired at the softening point or higher of the glass. As a result, the porous member 1 is accommodated in the concave portion 12, and the side surface is joined to the dense member 1 over the entire circumference while the lower surface is generally separated from the bottom surface 13 of the concave portion 12. Member 2 is formed. Further, a substantially cylindrical space whose upper and lower sides are defined by the lower surface of the porous member 2 and the bottom surface 13 of the recess 12 is formed at the same time as the primary vacuum path R1.

As shown in FIG. 2, the porous member 2 has a secondary vacuum path R2 composed of open pores 24 communicating from the surface 6 to the lower surface 7. A coating 22 is formed on the surface 6 of the porous member 2 to cover the upper surface of the porous member 2 or the ceramic particles 21 in the vicinity of the upper surface, at least partially, preferably completely. The portion where the coating film 22 partially covers the surface 6 of the porous member 2 or the ceramic particles 21 near the surface 6 is a part of the wall surface in which a part of the coating film 22 constitutes the opening holes 24 of the porous member 2. Also covers, an opening 23 is formed in a part of the coating film 22. The film 22 may be formed of a sprayed film, and its porosity is, for example, 1 to 20%, preferably 1 to 6%. When the porosity of the coating 22 is less than 1%, the adhesion between the particles constituting the porous member 2 and the coating 22 is lowered, and when the porosity of the coating 22 exceeds 20%, the coating 22 itself is separated from the porous member 2. It becomes easy to detach. The thickness of the coating film 22 is, for example, 1 to 300 [μm], preferably 1 to 30 [μm]. If the coating 22 is thicker than 300 μm, the air permeability of the secondary vacuum path R2 is impaired. If the coating film 22 is thinner than 1 μm, the effect of suppressing the shedding of the particles constituting the porous member 2 is reduced.

When the coating 22 completely covers the ceramic particles 21 on the upper surface 4 or the vicinity of the upper surface 4 of the porous member 2 and covers the opening 23 of the opening hole 24 of the porous member 2 in a closed state, the coating 22 itself covers the porous member 2. Since it is a porous body having a porosity different from that of the porous member 2, the open pores existing in the coating film 22 and the open pores 24 of the porous member 2 are combined to form a secondary vacuum path R2. The ceramic particles 21 show an island-shaped ceramic structure in a cross-sectional view.

The coating film 22 may be formed by a plasma spraying method. An inert gas such as Ar gas is passed between the pair of electrodes to generate an electric discharge to generate a plasma jet derived from the inert gas, and a raw material powder is supplied to the plasma jet to supply a porous member as a base material. By spraying on 2, the spray film derived from the raw material powder is formed as the coating film 22.

The coating 22 may be formed by the mHVOF thermal spraying method. A thermal spray film derived from the raw material powder is formed as a coating film 22 by supplying the raw material powder or a slurry thereof to a flame made of acetylene, ethylene, or propar and spraying the raw material powder or a slurry thereof onto the porous member 2 which is the base material.

The coating film 22 may be formed by an ion plating method. The porous member 2 which is the base material is housed in the chamber, and the chamber is put into a high vacuum state (for example, 10 ^-5 to 10 ^-3 [Pa]), and then an inert gas (argon, etc.) or a reactive gas (nitrogen, hydrocarbon) is placed. Inject hydrogen, etc.). By heating and evaporating the raw material (metal) with an electron beam from an electron gun (thermoelectron generating cathode), plasma ions derived from the raw material are generated, and the compound with the reactive gas is left in the porous member 2. The spray film derived from the raw material powder is formed as the coating film 22.

In addition, the coating film 22 may be formed by a plasma CVD method, a sputtering method, or the like.

When the substrate W is placed on the upper surface of the coating film 22, the upper and lower sides are defined with respect to the substrate W by the gap between the communication path 10, the bottom surface 13 of the recess 12 of the dense member 1 and the back surface 7 of the porous member 2. A vacuum suction force is applied through the primary vacuum path R1 that is formed and the secondary vacuum path R2 that is composed of the open pores 24 of the porous member 2 and the open pores that exist in the coating 22 to cause the substrate W to work. Adsorb and hold.

[Example]
[Example 1]
A substantially disk-shaped alumina sintered body having an outer diameter of 360 [mm] and a thickness of 30 [mm] was produced as the dense member 1. The compact member 1 is formed with a recess 12 that is recessed in a substantially circular shape from the upper surface 4 having a diameter of 300 [mm] and a depth of 5 [mm], and the compact member 1 is formed from the central portion of the bottom surface 13 of the recess 12. A through hole having a substantially circular cross section having a diameter of 10 [mm] was formed as a communication path 10 over the bottom surface 5 of 1.

A first alumina raw material powder (average particle size 120 [μm]), a second alumina raw material powder (average particle size 60 [μm]), borosilicate glass having an average particle size of 15 [μm] and distilled water as glass powder. A slurry was prepared by kneading at a mass ratio of 2: 1: 1: 1.

After filling the communication path 10 and the primary vacuum path R1 with the resin (disappearing member), the recess 12 of the dense member 1 was filled with the slurry, and the compact member 1 was vibrated to settle the powder in the slurry. .. If necessary, the slurry may be defoamed. Then, the water content of the slurry was evaporated by a drying treatment at 100 ° C., and the slurry was heat-treated at 1000 ° C. at 2 to 20 [hr] to prepare a porous member 2 composed of alumina particles and glass.

Then, the vacuum suction member 3 of Example 1 was produced by forming a coating film 22 made of alumina on the surface 6 of the porous member 2 by the plasma spraying method.

[Example 2]
The same conditions as in Example 1 except that a coating film 22 made of alumina was formed on the surface 6 of the porous member 2 using alumina powder (D50: 4 [μm]) as a raw material by the HVOF thermal spraying method instead of the plasma spraying method. The vacuum suction member 3 of Example 2 was produced.

[Example 3]
Example 3 under the same conditions as in Example 2 except that a coating film 22 made of silicon was formed on the surface 6 of the porous member 2 using silicon powder (D50: 2.7 [μm]) as a raw material by the HVOF thermal spraying method. The vacuum suction member 3 of the above was produced.

[Example 4]
By the ion plating method, Ti was used as a raw material, N ₂ was used as a reactive gas, and a coating film 22 made of TiN was formed on the surface 6 of the porous member 2 under the same conditions as in Example 1. The vacuum suction member 3 of Example 4 was produced.

[Comparison example]
[Comparative Example 1]
The vacuum suction member of Comparative Example 1 was produced under the same conditions as in Example 1 except that the coating 22 was not formed on the surface 6 of the porous member 2. That is, the surface 6 of the porous member 2 becomes the mounting surface of the substrate W.

(Evaluation method)
The thickness of the coating 22 of the vacuum suction member of each of the examples and the comparative examples was measured by SEM observation of the cross section. The porosity of the coating 22 of the vacuum suction member of each of the examples and the comparative examples was measured by the Archimedes method for the porous member 2 in accordance with JIS R1634, and the coating 22 was measured by the Archimedes method or the apparent volume by SEM observation. It was measured by the weight porosity method determined based on the specific gravity.

After the substrate W was placed on the upper surface of the coating film 22 of the vacuum suction member 3 of each of the examples and the comparative examples or on the upper surface of the porous member 2, scratches and scratches on the surface of the substrate W were evaluated. The evaluation method is based on JIS H0614, using a fluorescent lamp as a light source, and inspecting the entire surface of the substrate W with an illuminance of 1000 to 2000 lux on the surface of the substrate W. When the cumulative length is 300 (mm) / 4 or less of the diameter of the substrate W, it is judged as “◯”, and when it is more than that, it is judged as “x”.

The pressure in the vacuum suction path (communication path 10 → primary vacuum path R1 → secondary vacuum path R2) when the substrate W was sucked and held by the vacuum suction member 3 was measured as an index of the suction holding force. The sheet resistivity of the film 22 was measured using a high resistance / resistivity meter, Hi-Lester UX (manufactured by Mitsubishi Chemical Anateric Corporation) MCP-HT800. The surface potential of the substrate W when the substrate W was sucked and held by the vacuum suction member 3 was measured using a surface potential system # 344 (manufactured by Trek Japan).

The evaluation results are summarized in Table 1.

The following can be seen from Table 1. According to the vacuum suction member of each embodiment, no scratches or the like were found on the substrate W after suction holding, whereas according to the vacuum suction member of Comparative Example 1, the substrate W after suction holding was scratched or the like. Was seen. The suction holding force of the substrate W of the vacuum suction member of each example was not inferior to that of the vacuum suction member of Comparative Example 1. According to the vacuum suction members of Examples 3 and 4, it was shown that the coating film 22 had conductivity, and the substrate W was suppressed from being charged as compared with Comparative Example 1.

1 ... Dense member, 2 ... Porous member, 3 ... Vacuum suction member, 4 ... Top surface, 5 ... Bottom surface, 6 ... Surface surface, 7 ... Back surface, 8 ... Side surface, 10 ... Communication path, 12 ... Recession, 13 ... Bottom surface , 21 ... Ceramic particles, 22 ... Coating, 23 ... Opening, 24 ... Open pores, 25 ... Coating surface, R1 ... Primary vacuum path, R2 ... Secondary vacuum path.

Claims (4)

A vacuum suction member that has a porous member and holds the substrate by suction.
A coating covering the upper surface of the porous member is provided, the porosity of the coating is smaller than the porosity of the porous member, the thickness of the coating is 1 μm or more and 30 μm or less, and the porous member has. At least a part of the vacuum path formed by the communication of the open pores is maintained without being blocked by the coating, and at least a part of the porous member is composed of ceramic particles, and the coating is a ceramic spray film. vacuum suction member, characterized in der Rukoto. The vacuum suction member according to claim 1, wherein the porosity of the coating film is 1% or more and 20% or less. The vacuum suction member according to claim 1, wherein the coating film is a conductive film. A dense material that has an upper surface and a back surface and is formed with a recess that is recessed in the direction from the upper surface to the back surface and a communication path formed by a through hole provided from the back surface to the bottom surface of the recess. Parts and
A porous member housed in the recess of the dense member, having an upper surface and a back surface, and having a predetermined porosity.
A vacuum suction member for sucking and holding a substrate.
The upper surface of the porous member is provided with a coating having a porosity lower than that of the porous member, and the thickness of the coating is 1 μm or more and 30 μm or less.
At least a part of the porous member is composed of ceramic particles, and the coating film is a ceramic sprayed film.
Communication between the front surface of the coating and the back surface of the porous member in the secondary vacuum path composed of the open pores of the porous member or the open pores existing in the porous member and the coating is maintained. A vacuum suction member characterized by being present.

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