CN118919476A - Electrostatic chuck device - Google Patents

Abstract

An electrostatic chuck device (1) of the present invention is provided with: a plurality of internal electrodes (20); an insulating organic film (40) provided on both sides of the internal electrode (20) in the thickness direction; and a ceramic layer (60) laminated on the upper surface (2 a) in the thickness direction of the laminate (2) including at least the internal electrode (20) and the insulating organic film (40) with an intermediate layer (50) interposed therebetween.

Description

Electrostatic chuck device

This application is a divisional application of a patent application with an application date of December 25, 2019, application number 201980086522.9, and invention name “Electrostatic Chuck Device”.

Technical Field

The invention relates to an electrostatic chuck device.

Background Art

When semiconductor integrated circuits are manufactured using semiconductor wafers, or when liquid crystal panels are manufactured using insulating substrates such as glass substrates and films, substrates such as semiconductor wafers, glass substrates, and insulating substrates need to be adsorbed and held at a specified location. Therefore, in order to adsorb and hold these substrates, mechanical chucks and vacuum chucks based on mechanical methods are used. However, these holding methods have problems such as difficulty in uniformly holding the substrate (adsorbate), inability to use in a vacuum, and excessive temperature rise on the sample surface. Therefore, in recent years, electrostatic chuck devices that can solve these problems have been used when holding the adsorbate.

The electrostatic chuck device has a conductive support member that serves as an internal electrode, and a dielectric layer composed of a dielectric material covering the conductive support member as a main part. The adsorbed body can be adsorbed by the main part. If a voltage is applied to the internal electrode in the electrostatic chuck device to generate a potential difference between the adsorbed body and the conductive support member, an electrostatic adsorption force is generated between the dielectric layers. As a result, the adsorbed body is supported to be roughly flat relative to the conductive support member.

As conventional electrostatic chuck devices, there are known electrostatic chuck devices in which an insulating organic film is stacked on an internal electrode to form a dielectric layer (for example, see Patent Document 1). Also, there are known electrostatic chuck devices in which a dielectric layer is formed by spraying ceramics on an internal electrode (for example, see Patent Document 2). Also, there are known electrostatic chuck devices in which a ceramic layer is formed by spraying ceramics on an insulating organic film stacked on an internal electrode (for example, see Patent Document 3).

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2004-235563

Patent Document 2: Japanese Utility Model Publication No. 6-36583

Patent Document 3: Japanese Patent No. 5054022

Summary of the invention

Technical problem to be solved by the invention

The electrostatic chuck device described in Patent Document 1 has excellent adsorption force by utilizing the Coulomb force formed by a dielectric layer composed of an insulating organic film provided on an internal electrode. However, the electrostatic chuck device has the following technical problems: low resistance to the plasma environment used by the dry etching device and short product life.

In addition, an electrostatic chuck device having a dielectric layer formed by spraying ceramic on an internal electrode as described in Patent Document 2 has plasma resistance. However, since there are gaps between ceramic particles, it is not only difficult to obtain stable insulation, but also the dielectric layer must be thickened to ensure insulation. Therefore, as an electrostatic chuck device that uses Coulomb force to adsorb an adsorbed object, there is a technical problem that it is difficult to obtain a high adsorption force.

In addition, in an electrostatic chuck device having a ceramic layer formed by spraying ceramic on an insulating organic film stacked on an internal electrode as described in Patent Document 3, since the ceramic layer is sprayed on the insulating organic film, it is necessary to form a concave-convex surface on the insulating organic film. However, the insulating property of the insulating organic film is reduced by forming the concave-convex surface and spraying the ceramic. When used as an electrostatic chuck device, the thickness of the ceramic layer is required to be at least 100 μm. In addition, when spraying ceramic on the insulating organic film, the end of the insulating organic film cannot be covered by the ceramic layer. When the end of the insulating organic film is exposed, the plasma resistance of the electrostatic chuck device is reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrostatic chuck device having excellent plasma resistance and voltage resistance and also excellent adsorption properties.

Technical solutions to solve problems

The present invention has the following aspects.

[1] An electrostatic chuck device, characterized in that it comprises: a plurality of internal electrodes; an insulating organic film provided on both sides of the internal electrodes in a thickness direction; and a ceramic layer stacked via an intermediate layer on an upper surface in a thickness direction of a stack including at least the internal electrodes and the insulating organic film.

[2] The electrostatic chuck device according to [1], wherein the ceramic layer covers the entire outer surface of the stacked body via the intermediate layer.

[3] The electrostatic chuck device according to [1] or [2], characterized in that the ceramic layer comprises: a base layer; and a surface layer formed on the upper surface of the base layer and having projections and depressions.

[4] The electrostatic chuck device according to any one of [1] to [3], wherein the intermediate layer includes: at least one of an organic insulating resin and an inorganic insulating resin, and at least one of an inorganic filler and a fibrous filler.

[5] The electrostatic chuck device according to [4], wherein the inorganic filler is at least one of a spherical powder and a random powder.

[6] The electrostatic chuck device according to [5], characterized in that the spherical powder and the random powder are at least one selected from the group consisting of aluminum oxide, silicon dioxide and yttrium oxide.

[7] The electrostatic chuck device according to any one of [4] to [6], wherein the fibrous filler is at least one selected from the group consisting of plant fibers, inorganic fibers, and fiberized organic resins.

[8] The electrostatic chuck device according to any one of [1] to [7], wherein the insulating organic film is a polyimide film.

[9] An electrostatic chuck device according to any one of [1] to [8], characterized in that the insulating organic film is composed of a first insulating organic film arranged on the lower surface side of the internal electrode in the thickness direction and a second insulating organic film arranged on the upper surface side of the internal electrode in the thickness direction, a first adhesive layer is arranged on the surface of the first insulating organic film on the opposite side of the internal electrode, and a second adhesive layer is arranged between the first insulating organic film and the internal electrode arranged on the upper surface side in the thickness direction of the first insulating organic film and the second insulating organic film, and the total thickness of the first adhesive layer, the thickness of the first insulating organic film, the thickness of the internal electrode, the thickness of the second adhesive layer, the thickness of the second insulating organic film, the thickness of the intermediate layer and the thickness of the ceramic layer is less than 200 μm.

Effects of the Invention

According to the present invention, it is possible to provide an electrostatic chuck device having excellent plasma resistance and voltage resistance and also excellent adsorption properties.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a schematic structure of an electrostatic chuck device according to the present invention, taken along a height direction of the electrostatic chuck device.

DETAILED DESCRIPTION

Next, an electrostatic chuck device according to an embodiment of the present invention will be described. In the drawings used in the following description, the dimensional ratios of the components are not necessarily the same as the actual ones.

In addition, the present embodiment is a specific description for better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified.

[Electrostatic chuck device]

FIG. 1 is a cross-sectional view showing a schematic structure of an electrostatic chuck device according to the present embodiment, taken along a height direction of the electrostatic chuck device.

As shown in FIG1 , the electrostatic chuck device 1 of the present embodiment includes: a substrate 10, a plurality of internal electrodes 20, an adhesive layer 30, an insulating organic film 40, an intermediate layer 50, and a ceramic layer 60. Specifically, as shown in FIG1 , the electrostatic chuck device 1 of the present embodiment includes: a substrate 10, a first internal electrode 21, a second internal electrode 22, a first adhesive layer 31, a second adhesive layer 32, a first insulating organic film 41, a second insulating organic film 42, an intermediate layer 50, and a ceramic layer 60.

In the electrostatic chuck device 1 of the present embodiment, on the surface 10a of the substrate 10 (the upper surface in the thickness direction of the substrate 10), a first adhesive layer 31, a first insulating organic film 41, a first internal electrode 21 and a second internal electrode 22, a second adhesive layer 32, a second insulating organic film 42, an intermediate layer 50 and a ceramic layer 60 are stacked in order.

The insulating organic film 40 is provided on both sides (the upper surface 20a in the thickness direction of the internal electrode 20 and the lower surface 20b in the thickness direction of the internal electrode 20) of the internal electrode 20. Specifically, the second insulating organic film 42 is provided on the upper surface 21a side in the thickness direction of the first internal electrode 21 and the upper surface 22a side in the thickness direction of the second internal electrode 22. In addition, the first insulating organic film 41 is provided on the lower surface 21b side in the thickness direction of the first internal electrode 21 and the lower surface 22b side in the thickness direction of the second internal electrode 22.

A first adhesive layer 31 is provided on the surface of the first insulating organic film 41 opposite to the internal electrode 20 (lower surface 41 b of the first insulating organic film 41 ). A second adhesive layer 32 is provided between the first insulating organic film 41 and the internal electrode 20 provided on the upper surface 41 a in the thickness direction of the first insulating organic film 41 , and the second insulating organic film 42 .

The total thickness of the first adhesive layer 31, the first insulating organic film 41, the internal electrode 20, the second adhesive layer 32, the second insulating organic film 42, the intermediate layer 50, and the ceramic layer 60 (ceramic base layer 61, ceramic surface layer 62) (hereinafter referred to as "total thickness (1)") is preferably 200 μm or less, more preferably 170 μm or less. If the total thickness (1) is 200 μm or less, the electrostatic chuck device 1 has excellent withstand voltage characteristics and plasma resistance, resulting in excellent adsorption force.

The total thickness of the first adhesive layer 31, the first insulating organic film 41, the internal electrode 20, the second adhesive layer 32, and the second insulating organic film 42 (hereinafter referred to as "total thickness (2)") is preferably 110 μm or less, and more preferably 90 μm or less. When the total thickness (2) is 110 μm or less, the electrostatic chuck device 1 has excellent withstand voltage characteristics and plasma resistance, resulting in excellent adsorption force.

The total thickness of the second adhesive layer 32 and the second insulating organic film 42 (hereinafter referred to as "total thickness (3)") is preferably 50 μm or less, and more preferably 40 μm or less. When the total thickness (2) is 50 μm or less, the electrostatic chuck device 1 has excellent voltage resistance and plasma resistance, resulting in excellent adsorption force.

A ceramic layer 60 is stacked via an intermediate layer 50 on an upper surface 2 a (an upper surface 42 a of the second insulating organic film 42 ) in the thickness direction of the stacked body 2 including at least the internal electrode 20 and the insulating organic film 40 .

As shown in Figure 1, the ceramic layer 60 preferably covers the entire outer surface 2b of the stack 2 (the upper surface 2a of the stack 2, the side surface (the surface along the thickness direction of the stack 2, the side surface of the first adhesive layer 31, the side surface of the second adhesive layer 32, the side surface of the first insulating organic film 41 and the side surface of the second insulating organic film 42) via the intermediate layer 50. In other words, the intermediate layer 50 preferably covers the entire outer surface of the stack 2, and the ceramic layer 60 covers the entire outer surface of the intermediate layer 50 (the upper surface 50a of the intermediate layer 50, the side surface (the surface along the thickness direction of the stack 2) 50b).

As shown in FIG. 1 , the ceramic layer 60 preferably includes a ceramic base layer 61 and a ceramic surface layer 62 formed on an upper surface 61 a of the ceramic base layer 61 (the upper surface in the thickness direction of the ceramic base layer 61 ) and having projections and depressions.

The total thickness of the ceramic base layer 61, the ceramic surface layer 62, the intermediate layer 50, the second adhesive layer 32, and the second insulating organic film 42 (hereinafter referred to as "total thickness (4)") is preferably 125 μm or less, and more preferably 110 μm or less. If the total thickness (4) is 125 μm or less, the electrostatic chuck device 1 has excellent withstand voltage characteristics and plasma resistance, resulting in excellent adsorption force.

The first internal electrode 21 and the second internal electrode 22 may be in contact with the first insulating organic film 41 or the second insulating organic film 42. In addition, as shown in FIG1 , the first internal electrode 21 and the second internal electrode 22 may be formed inside the second adhesive layer 32. The arrangement of the first internal electrode 21 and the second internal electrode 22 may be appropriately designed.

The first internal electrode 21 and the second internal electrode 22 are independent of each other, so not only voltages of the same polarity but also voltages of different polarities can be applied. The first internal electrode 21 and the second internal electrode 22 are not particularly limited in their electrode pattern and shape as long as they can adsorb adsorbed bodies such as conductors, semiconductors and insulators. In addition, only the first internal electrode 21 can be provided as a single pole.

The electrostatic chuck device 1 of this embodiment is not particularly limited to other layer structures as long as the ceramic layer 60 is stacked at least on the upper surface 42a of the second insulating organic film 42 via the intermediate layer 50. For example, the substrate 10 shown in FIG. 1 may not be provided.

The substrate 10 is not particularly limited, and examples thereof include a ceramic substrate, a silicon carbide substrate, and a metal substrate made of aluminum, stainless steel, or the like.

The internal electrode 20 is not particularly limited as long as it is an electrode made of a conductive material that can show electrostatic adsorption force when a voltage is applied. As the internal electrode 20, for example, a film made of a metal such as copper, aluminum, gold, silver, platinum, chromium, nickel, tungsten, or a film made of at least two metals selected from the above metals is preferably used. Examples of such a metal film include film formation by evaporation, plating, sputtering, or the like, and film formation by coating and drying a conductive paste. Specifically, metal foils such as copper foil can be used.

The thickness of the internal electrode 20 is not particularly limited as long as the thickness of the second adhesive layer 32 is greater than the thickness of the internal electrode 20. The thickness of the internal electrode 20 is preferably 20 μm or less. If the thickness of the internal electrode 20 is 20 μm or less, it is difficult to generate unevenness on the upper surface 42a when the second insulating organic film 42 is formed. As a result, when the ceramic layer 60 is formed on the second insulating organic film 42 and when the ceramic layer 60 is polished, it is difficult to generate defects.

The thickness of the internal electrode 20 is preferably 1 μm or more. When the thickness of the internal electrode 20 is 1 μm or more, sufficient bonding strength can be obtained when the internal electrode 20 is bonded to the first insulating organic film 41 or the second insulating organic film 42 .

When voltages of different polarities are applied to the first internal electrode 21 and the second internal electrode 22, the interval between the adjacent first internal electrodes 21 and the second internal electrodes 22 (the interval in a direction perpendicular to the thickness direction of the internal electrode 20) is preferably 2 mm or less. If the interval between the first internal electrode 21 and the second internal electrode 22 is 2 mm or less, sufficient electrostatic force is generated between the first internal electrode 21 and the second internal electrode 22, and sufficient adsorption force is generated.

It is preferred that the distance from the internal electrode 20 to the adsorbate, that is, the distance from the upper surface 21a of the first internal electrode 21 and the upper surface 22a of the second internal electrode 22 to the adsorbate adsorbed on the ceramic surface layer 62 (the total thickness of the second adhesive layer 32, the second insulating organic film 42, the intermediate layer 50, the ceramic base layer 61, and the ceramic surface layer 62 present on the upper surface 21a of the first internal electrode 21 and the upper surface 22a of the second internal electrode 22) is 50 μm to 125 μm. If the distance from the internal electrode 20 to the adsorbate is 50 μm or more, the insulation of the laminate composed of the second adhesive layer 32, the second insulating organic film 42, the intermediate layer 50, the ceramic base layer 61, and the ceramic surface layer 62 can be ensured. On the other hand, if the distance from the internal electrode 20 to the adsorbate is 125 μm or less, sufficient adsorption force is generated.

As the adhesive constituting the adhesive layer 30, an adhesive having one or more resins selected from epoxy resin, phenolic resin, styrene block copolymer, polyamide resin, acrylonitrile-butadiene copolymer, polyester resin, polyimide resin, silicone resin, amine compound, bismaleimide compound, etc. as the main component can be used.

As epoxy resins, there can be cited: bifunctional or multifunctional epoxy resins such as bisphenol epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, trihydroxyphenylmethane epoxy resins, tetraglycidylphenol alkane epoxy resins, naphthalene epoxy resins, diglycidyl diphenylmethane epoxy resins, and diglycidyl biphenyl epoxy resins. Among these, bisphenol epoxy resins are preferred. Among bisphenol epoxy resins, bisphenol A epoxy resins are particularly preferred. In addition, when epoxy resin is used as the main component, curing agents and curing accelerators for epoxy resins such as imidazoles, tertiary amines, phenols, dicyandiamides, aromatic diamines, and organic peroxides can also be used as needed.

Examples of the phenolic resin include alkylphenolic resins, p-phenylphenolic resins, novolac resins such as bisphenol A-type phenolic resins, resol resins, and polyphenylene phenolic resins.

Examples of the styrene-based block copolymer include styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and styrene-ethylene-propylene-styrene copolymer (SEPS).

The thickness of the adhesive layer 30 (the first adhesive layer 31 and the second adhesive layer 32) is not particularly limited, but is preferably 5 μm to 20 μm, and more preferably 10 μm to 20 μm. If the thickness of the adhesive layer 30 (the first adhesive layer 31 and the second adhesive layer 32) is 5 μm or more, the function of the adhesive is fully exerted. On the other hand, if the thickness of the adhesive layer 30 (the first adhesive layer 31 and the second adhesive layer 32) is 20 μm or less, the insulation between the internal electrodes 20 can be ensured without compromising the adsorption force.

The material constituting the insulating organic film 40 is not particularly limited, and for example, polyesters such as polyethylene terephthalate, polyolefins such as polyethylene, polyimide, polyamide, polyamide-imide, polyethersulfone, polyphenylene sulfide, polyetherketone, polyetherimide, triacetylcellulose, silicone rubber, polytetrafluoroethylene, etc. can be used. Among them, polyesters, polyolefins, polyimide, silicone rubber, polyetherimide, polyethersulfone, polytetrafluoroethylene are preferred from the point of view of excellent insulation, and polyimide is more preferred. As a polyimide film, for example, Kapton (trade name) manufactured by Toray DuPont Co., Ltd. and Upilex (trade name) manufactured by Ube Industries, Ltd. can be used.

The thickness of the insulating organic film 40 (the first insulating organic film 41 and the second insulating organic film 42) is not particularly limited, but is preferably 10 μm to 100 μm, and more preferably 10 μm to 50 μm. If the thickness of the insulating organic film 40 (the first insulating organic film 41 and the second insulating organic film 42) is 10 μm or more, insulation can be ensured. On the other hand, if the thickness of the insulating organic film 40 (the first insulating organic film 41 and the second insulating organic film 42) is 100 μm or less, sufficient adsorption force is generated.

The intermediate layer 50 preferably contains at least one of an organic insulating resin and an inorganic insulating resin, and at least one of an inorganic filler and a fibrous filler.

The organic insulating resin is not particularly limited, and examples thereof include polyimide-based resins, epoxy-based resins, and acrylic-based resins.

The inorganic insulating resin is not particularly limited, and examples thereof include silane-based resins and silicone-based resins.

The intermediate layer 50 preferably contains polysilazane. Examples of polysilazane include materials known in the art. Polysilazane may be organic polysilazane or inorganic polysilazane. These materials may be used alone or in combination of two or more.

The content of the inorganic filler in the intermediate layer 50 is preferably 100 to 300 parts by mass, more preferably 150 to 250 parts by mass, relative to 100 parts by mass of polysilazane. If the content of the inorganic filler in the intermediate layer 50 is within the above range, the inorganic filler particles can form unevenness on the surface of the resin film as the cured product of the intermediate layer 50, so that the powder of the spraying material can easily enter between the inorganic filler particles, thereby making the spraying material firmly adhered to the resin film surface.

The inorganic filler is not particularly limited, but is preferably at least one selected from the group consisting of alumina, silica, and yttrium oxide.

The inorganic filler is preferably at least one of a spherical powder and a random powder.

In addition, spherical powder refers to a spherical body with rounded corners of powder particles, and irregular powder refers to powder in a shape such as a crushed, plate-like, flaky, or needle-like shape that cannot be fixed.

The average particle size of the inorganic filler is preferably 1 μm to 20 μm. When the inorganic filler is a spherical powder, the diameter (outer diameter) is taken as the particle size, and when the inorganic filler is a random powder, the longest part of the shape is taken as the particle size.

It is preferred that the fibrous filler is at least one selected from the group consisting of plant fibers, inorganic fibers, and fiberized organic resins.

Examples of the plant fiber include pulp and the like.

Examples of the inorganic fibers include fibers made of alumina.

Examples of the fiberized organic resin include fibers made of aramid, Teflon (registered trademark), and the like.

The inorganic filler is preferably used together with the fibrous filler, and the total content of the inorganic filler and the fibrous filler is preferably 10 volume % to 80 volume % relative to the entire intermediate layer 50 (100 volume %). If the total content of the inorganic filler and the fibrous filler in the intermediate layer 50 is within the above range, the ceramic layer 60 can be uniformly formed on the intermediate layer 50 by thermal spraying.

The thickness of the intermediate layer 50 is preferably 1 μm to 40 μm, more preferably 5 μm to 20 μm. If the thickness of the intermediate layer 50 is 1 μm or more, the ceramic layer 60 can be uniformly formed on the intermediate layer 50 by spraying without making the intermediate layer 50 partially thin. On the other hand, if the thickness of the intermediate layer 50 is 40 μm or less, sufficient adsorption force is generated.

The material constituting the ceramic layer 60 is not particularly limited, and examples thereof include boron nitride, aluminum nitride, zirconium oxide, silicon oxide, tin oxide, indium oxide, quartz glass, soda glass, lead glass, borosilicate glass, zirconium nitride, titanium oxide, etc. These materials may be used alone or in combination of two or more.

These materials are preferably in the form of powders having an average particle size of 1 μm to 25 μm. By using such powders, voids in the ceramic layer 60 can be reduced and the withstand voltage of the ceramic layer 60 can be improved.

The thickness of the ceramic base layer 61 is preferably 10 μm to 80 μm, and more preferably 40 μm to 60 μm. If the thickness of the ceramic base layer 61 is 10 μm or more, sufficient plasma resistance and voltage resistance are exhibited. On the other hand, if the thickness of the ceramic base layer 61 is 80 μm or less, sufficient adsorption force is generated.

The thickness of the ceramic surface layer 62 is preferably 5 μm to 20 μm. If the thickness of the ceramic surface layer 62 is 5 μm or more, the irregularities can be formed over the entire range of the ceramic surface layer 62. On the other hand, if the thickness of the ceramic surface layer 62 is 20 μm or less, sufficient adsorption force is generated.

The ceramic surface layer 62 can improve its adsorption force by polishing its surface, and can adjust the surface roughness to Ra.

Here, the surface roughness Ra means a value measured by a method specified in JIS B0601-1994.

The surface roughness Ra of the ceramic surface layer 62 is preferably 0.05 μm to 0.5 μm. If the surface roughness Ra of the ceramic surface layer 62 is within the above range, the adsorbate can be adsorbed well. When the surface roughness Ra of the ceramic surface layer 62 increases, the contact area between the adsorbate and the ceramic surface layer 62 becomes smaller, so the adsorption force also decreases.

In the electrostatic chuck device 1 of the present embodiment described above, there are provided: a plurality of internal electrodes 20; an insulating organic film 40 provided on both sides in the thickness direction of the internal electrode 20; and a ceramic layer 60 laminated on the upper surface 2a in the thickness direction of the laminate 2 including at least the internal electrode 20 and the insulating organic film 40 via the intermediate layer 50. Therefore, at least on the upper surface 2a side in the thickness direction of the laminate 2, the plasma resistance and the voltage resistance can be improved, and abnormal discharge during use can be suppressed. Therefore, the electrostatic chuck device 1 of the present embodiment is also excellent in adsorption.

In the electrostatic chuck device 1 of the present embodiment, as long as the ceramic layer 60 covers the entire outer surface of the stack 2 via the intermediate layer 50, the plasma resistance and voltage resistance can be improved on the upper surface 2a side and the side surface 2b side of the stack 2, and abnormal discharge during use can be suppressed. Therefore, the adsorption property of the electrostatic chuck device 1 of the present embodiment is further improved.

In the electrostatic chuck device 1 of the present embodiment, the ceramic layer 60 includes a ceramic base layer 61 and a ceramic surface layer 62 formed on an upper surface 61 a of the ceramic base layer 61 and having projections and depressions, thereby enabling control to achieve a desired adsorption force.

In the electrostatic chuck device 1 of the present embodiment, the intermediate layer 50 includes at least one of an organic insulating resin and an inorganic insulating resin and at least one of an inorganic filler and a fibrous filler, thereby allowing the ceramic layer 60 to be uniformly formed on the intermediate layer 50 .

In the electrostatic chuck device 1 of the present embodiment, the inorganic filler is at least one of a spherical powder and an irregular powder, thereby, the filling state in the resin of the intermediate layer 50 can be designed to be uniformly dispersed or densely filled, and it can also be designed so that a part of the filler is exposed from the resin, thereby improving the close contact with the ceramic base layer 61.

In the electrostatic chuck device 1 of the present embodiment, the fibrous filler is at least one selected from the group consisting of plant fibers, inorganic fibers and fiberized organic resins, thereby improving the strength and toughness of the intermediate layer 50, improving the close contact with the ceramic base layer 61 achieved by arranging fibers on the surface of the intermediate layer 50, and alleviating deformation caused by the difference in thermal expansion coefficients between the ceramic base layer 61 and the insulating organic film 40 separated by the intermediate layer 50.

In the electrostatic chuck device 1 of the present embodiment, the insulating organic film is a polyimide film, thereby improving the withstand voltage.

In the electrostatic chuck device 1 of the present embodiment, the inorganic filler composed of spherical powder and random powder is at least one selected from the group consisting of alumina, silica, and yttrium oxide, thereby improving plasma resistance and voltage resistance.

[Method for manufacturing electrostatic chuck]

1 , a method for manufacturing an electrostatic chuck device 1 according to the present embodiment will be described.

A metal such as copper is deposited on the surface 41a of the first insulating organic film 41 (the upper surface in the thickness direction of the first insulating organic film 41) to form a metal film. Then, the metal film is etched to pattern into a predetermined shape to form the first internal electrode 21 and the second internal electrode 22.

Next, the second insulating organic film 42 is bonded onto the upper surface 20 a of the internal electrode 20 via the second adhesive layer 32 .

Next, the stack consisting of the first insulating organic film 41, the internal electrode 20, the second adhesive layer 32 and the second insulating organic film 42 is joined to the surface 10a of the substrate 10 via the first adhesive layer 31 in such a way that the lower surface 41b of the first insulating organic film 41 is located on the surface 10a side of the substrate 10.

Next, the intermediate layer 50 is formed so as to cover the entire outer surface of the laminated body 2 including the internal electrode 20 and the insulating organic film 40 .

The method for forming the intermediate layer 50 is not particularly limited as long as the intermediate layer 50 can be formed to cover the entire outer surface of the laminate 2. Examples of the method for forming the intermediate layer 50 include bar coating, spin coating, and spray coating.

Next, the ceramic base layer 61 is formed so as to cover the entire outer surface of the intermediate layer 50 .

The method for forming the ceramic base layer 61 includes, for example: applying a slurry containing a material constituting the ceramic base layer 61 to the entire outer surface of the intermediate layer 50, and sintering it to form the ceramic base layer 61; spraying the material constituting the ceramic base layer 61 to the entire outer surface of the intermediate layer 50 to form the ceramic base layer 61, etc.

Here, thermal spraying refers to a method of forming a film by heating and melting a material to be a coating layer (the ceramic base layer 61 in this embodiment) and then injecting it toward a treatment object using compressed gas.

Next, the ceramic surface layer 62 is formed on the upper surface 61 a of the ceramic base layer 61 .

The method for forming the ceramic surface layer 62 includes, for example: applying a mask of a prescribed shape to the upper surface 61a of the ceramic base layer 61, and then spraying the material constituting the ceramic surface layer 62 onto the upper surface 61a of the ceramic base layer 61 to form the ceramic surface layer 62; spraying the material constituting the ceramic surface layer 62 onto the entire upper surface 61a of the ceramic base layer 61 to form the ceramic surface layer 62, and then cutting the ceramic surface layer 62 by sandblasting to form the ceramic surface layer 62 into a concave-convex shape, etc.

Through the above steps, the electrostatic chuck device 1 of this embodiment can be manufactured.

Example

Hereinafter, the present invention will be described in more detail by way of Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1]

A 9 μm thick copper is plated on one side of a polyimide film (trade name: Kapton, manufactured by Toray DuPont) with a film thickness of 12.5 μm as the first insulating organic film 41. A photoresist is applied to the surface of the copper foil, and then a development process is performed after pattern exposure, and unnecessary copper foil is removed by etching. Then, the copper foil on the polyimide film is washed and the photoresist is removed, thereby forming the first internal electrode 21 and the second internal electrode 22. An insulating adhesive sheet semi-cured by drying and heating is laminated on the first internal electrode 21 and the second internal electrode 22 as the second adhesive layer 32. As the insulating adhesive sheet, a material formed into a sheet by mixing and dissolving 27 parts by mass of bismaleimide resin, 3 parts by mass of diaminosiloxane, 20 parts by mass of resol phenolic resin, 10 parts by mass of biphenyl epoxy resin, and 240 parts by mass of ethyl acrylate-butyl acrylate-acrylonitrile copolymer in an appropriate amount of tetrahydrofuran is used. Then, a 12.5 μm thick polyimide film (trade name: Kapton, manufactured by DuPont Toray) was attached as the second insulating organic film 42 , and a laminated body bonded by heat treatment was obtained. The thickness of the second adhesive layer 32 after drying was 20 μm.

In addition, a sheet composed of an insulating adhesive having the same component as the semi-cured insulating adhesive sheet is laminated as a first adhesive layer 31 on the surface of the first insulating organic film 41 of the laminate on the opposite side to the surface on which the first internal electrode 21 and the second internal electrode 22 are formed. Then, the laminate is attached to the aluminum substrate 10 and bonded by heat treatment. In addition, the thickness of the first adhesive layer 31 after drying is 10 μm.

Next, 100 parts by mass of polysilazane and 200 parts by mass of an inorganic filler composed of aluminum oxide (average particle size: 3 μm) were mixed in butyl acetate as a diluent, and the inorganic filler was uniformly dispersed using an ultrasonic disperser to prepare a coating material.

Next, the coating was sprayed on the surface of the second insulating organic film 42 of the laminate bonded to the substrate 10 and the surface of the laminate 2, and then heated and dried to form an intermediate layer 50. The thickness of the dried intermediate layer 50 on the surface of the second insulating organic film 42 was 10 μm.

Next, aluminum oxide (Al ₂ O ₃ ) powder (average particle size: 8 μm) was sprayed onto the entire surface of the intermediate layer 50 by plasma spraying to form a ceramic base layer 61 having a thickness of 50 μm.

Next, a mask of a predetermined shape was applied to the surface of the ceramic base layer 61 , and then the above-mentioned aluminum oxide (Al ₂ O ₃ ) powder (average particle size: 8 μm) was thermally sprayed onto the surface of the ceramic base layer 61 to form a ceramic surface layer 62 having a thickness of 15 μm.

Next, the adsorption surface of the ceramic surface layer 62 for adsorbing the adsorbed object is plane-ground by a diamond grinding wheel, thereby obtaining the electrostatic chuck device of Example 1.

The surface of the obtained electrostatic chuck device was measured in accordance with JIS B0601-1994. As a result, the surface roughness Ra was 0.3 μm.

[Example 2]

An electrostatic chuck device of Example 2 was obtained in the same manner as in Example 1 except that the thickness of the first insulating organic film 41 and the thickness of the second insulating organic film 42 were changed to 25 μm.

[Example 3]

The electrostatic chuck device of Example 3 is obtained in the same manner as in Example 1, except that in Example 1, the thickness of the first insulating organic film 41 and the thickness of the second insulating organic film 42 are changed to 38 μm, the thickness of the second adhesive layer 32 is changed to 10 μm, and the thickness of the first internal electrode 21 and the thickness of the second internal electrode 22 are changed to 5 μm.

[Comparative Example 1]

The electrostatic chuck device of Comparative Example 1 is obtained in the same manner as in Example 1, except that in Example 1, the thickness of the first insulating organic film 41 and the thickness of the second insulating organic film 42 are changed to 50 μm, the thickness of the ceramic base layer 61 is changed to 30 μm, the thickness of the intermediate layer 50 is changed to 15 μm, the thickness of the first internal electrode 21 and the thickness of the second internal electrode 22 are changed to 5 μm, and the thickness of the first adhesive layer 31 is changed to 20 μm.

[Comparative Example 2]

An electrostatic chuck device of Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that the thickness of the ceramic base layer 61 was changed to 50 μm.

[Comparative Example 3]

The electrostatic chuck device of Comparative Example 3 was obtained in the same manner as Comparative Example 2, except that in Comparative Example 2, the thickness of the ceramic surface layer 62 was changed to 20 μm, the thickness of the ceramic base layer 61 was changed to 80 μm, and the thickness of the intermediate layer 50 was changed to 30 μm.

[Comparative Example 4]

An electrostatic chuck device of Comparative Example 4 was obtained in the same manner as Comparative Example 3 except that aluminum oxide (Al ₂ O ₃ ) powder (average particle size: 8 μm) was directly sprayed onto the surface of the second insulating organic film 42 by plasma spraying without providing the intermediate layer 50 .

Table 1 shows the thickness of each layer of the electrostatic chuck devices obtained in Examples 1 to 3 and Comparative Examples 1 to 4 and the total value thereof.

[Table 1]

Next, the withstand voltage characteristics, the adsorption force, and the plasma resistance were evaluated using the electrostatic chuck devices obtained in Examples 1 to 3 and Comparative Examples 1 to 4. Table 2 shows the results.

[Evaluation items]

＜Withstand voltage characteristics＞

The withstand voltage characteristics were evaluated by applying a voltage of ±2.5 kV to the first internal electrode 21 and the second internal electrode 22 of the electrostatic chuck device under vacuum (10 Pa) by a high voltage power supply device and maintaining the voltage for 2 minutes. During the 2-minute period, visual observation was performed, and no change was considered "qualified", while insulation breakdown between the electrodes or between the insulating organic film and the ceramic layer was considered "unqualified".

＜Adsorption capacity＞

As for the adsorption force, a dummy wafer made of silicone is used as the adsorbate, and it is adsorbed on the surface of the electrostatic chuck device under vacuum (below 10Pa), and a voltage of ±2.5kV is applied to the first internal electrode 21 and the second internal electrode 22, and then maintained for 30 seconds. While maintaining the applied voltage, helium is allowed to flow from the through hole provided in the substrate 10, and the amount of helium leakage is measured while increasing the air pressure. The ability to stably adsorb the dummy wafer at an air pressure of 100Torr is considered "qualified", and the inability to stably adsorb is considered "unqualified". Stable adsorption means that the wafer will not float due to increasing the helium pressure, and the helium leakage will not increase sharply.

＜Plasma resistance＞

For plasma resistance, the electrostatic chuck device was set in a parallel plate RIE device, and then oxygen (10sccm) and carbon tetrafluoride gas (40sccm) were introduced using a high-frequency power supply (output 250W) under vacuum (below 20Pa), and the changes in the surface state of the electrostatic chuck device after 24 hours of exposure were visually observed. The surface was considered "qualified" if the ceramic layer remained on the entire surface, and "unqualified" if part of the ceramic layer disappeared and the insulating organic film was exposed.

[Table 2]

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Withstand voltage characteristics qualified qualified qualified qualified qualified qualified qualified Adsorption qualified qualified qualified qualified Failure Failure Failure Plasma resistance qualified qualified qualified Failure qualified qualified Failure

As can be seen from Table 2, the electrostatic chuck devices obtained by Examples 1 to 3 are films in which the distance from the surface 10a of the substrate 10 to the surface of the ceramic surface layer 62 is less than 200 μm, but it can be confirmed that the voltage resistance characteristics and plasma resistance are excellent, and the results show that the adsorption force is excellent.

On the other hand, the electrostatic chuck device obtained in Comparative Example 1 had a thin ceramic base layer 61, and therefore could not obtain sufficient plasma resistance. The electrostatic chuck devices obtained in Comparative Examples 2 and 3 had a distance from the surface 10a of the substrate 10 to the surface of the ceramic surface layer 62 exceeding 200 μm, and therefore it was confirmed that the adsorption force was poor.

In addition, since the electrostatic chuck device obtained in Comparative Example 4 does not have the intermediate layer 50, it can be confirmed that the ceramic sprayed material is not sufficiently attached to the surface of the second insulating organic film 42, and the plasma resistance is poor.

Industrial Applicability

According to the electrostatic chuck device of the present invention, by stacking a ceramic layer via an intermediate layer on the upper surface in the thickness direction of a stacked body including an internal electrode and an insulating organic film provided on both sides in the thickness direction, it is possible to obtain a high adsorption force while having excellent plasma resistance and voltage resistance characteristics. Therefore, according to the electrostatic chuck device of the present invention, a conductive body or semiconductor such as a wafer for a dry etching device in a semiconductor manufacturing process can be stably electrostatically adsorbed and held.

Description of reference numerals:

1: electrostatic chuck device; 2: laminate; 10: substrate; 20: internal electrode; 21: first internal electrode; 22: second internal electrode; 30: adhesive layer; 31: first adhesive layer; 32: second adhesive layer; 40: insulating organic film; 41: first insulating organic film; 42: second insulating organic film; 50: intermediate layer; 60: ceramic layer; 61: ceramic base layer; 62: ceramic surface layer.

Claims (9)

1. An electrostatic chuck device, characterized in that it comprises: multiple internal electrodes; an insulating organic film provided on both sides of the internal electrode in the thickness direction; and a ceramic layer laminated on an upper surface in a thickness direction of a laminate including at least the internal electrode and the insulating organic film via an intermediate layer, The intermediate layer contains polysilazane. 2. The electrostatic chuck device according to claim 1, characterized in that: The ceramic layer covers the entire outer surface of the stacked body via the intermediate layer. 3. The electrostatic chuck device according to claim 1, characterized in that: The ceramic layer includes: a base layer; and a surface layer formed on the upper surface of the base layer and having projections and depressions. 4. The electrostatic chuck device according to claim 1, characterized in that: The intermediate layer includes at least one of an organic insulating resin and an inorganic insulating resin, and at least one of an inorganic filler and a fibrous filler. 5. The electrostatic chuck device according to claim 4, characterized in that: The inorganic filler is at least one of spherical powder and irregular powder. 6. The electrostatic chuck device according to claim 5, characterized in that: The spherical powder and the irregular powder are at least one selected from the group consisting of aluminum oxide, silicon dioxide, and yttrium oxide. 7. The electrostatic chuck device according to claim 4, characterized in that: The fibrous filler is at least one selected from the group consisting of plant fiber, inorganic fiber and fiberized organic resin. 8. The electrostatic chuck device according to claim 1, characterized in that: The insulating organic film is a polyimide film. 9. The electrostatic chuck device according to any one of claims 1 to 8, characterized in that: The insulating organic film is composed of a first insulating organic film provided on the lower surface side of the internal electrode in the thickness direction and a second insulating organic film provided on the upper surface side of the internal electrode in the thickness direction. A first adhesive layer is provided on a surface of the first insulating organic film on the side opposite to the internal electrode. A second adhesive layer is provided between the first insulating organic film and the internal electrode provided on the upper surface side in the thickness direction of the first insulating organic film and the second insulating organic film, The total thickness of the first adhesive layer, the first insulating organic film, the internal electrode, the second adhesive layer, the second insulating organic film, the intermediate layer and the ceramic layer is less than 200 μm.