Electrostatic chuck and preparation method thereof

Abstract

The invention discloses an electrostatic chuck and a preparation method thereof, and belongs to the technical field of electrostatic chucks, and the preparation method comprises the following steps: S1, manufacturing a metal substrate layer through machining and welding processes, and reserving a water channel, a lift-pin hole, a helium hole and a threaded hole in the metal substrate layer; s2, manufacturing the lower dielectric layer through machining, processing the lower dielectric layer to a corresponding size, and leaving a lift-pin hole and a helium hole in the lower dielectric layer; s3, the upper surface of the metal base material layer is subjected to sand blasting treatment; s4, manufacturing the lower dielectric layer on the upper surface of the metal substrate layer through a plasma spraying process; s5, performing hole sealing treatment on the lower dielectric layer; s6, performing sand blasting treatment on the upper surface of the lower dielectric layer; s7, manufacturing an upper dielectric layer on the lower dielectric layer through a plasma spraying process; and S8, manufacturing a side dielectric layer on the side surfaces of the metal substrate and the dielectric layer through a plasma spraying process.

Description

Technical Field

[0001] The invention relates to the technical field of electrostatic chucks, and in particular to an electrostatic chuck and a preparation method thereof. Background Art

[0002] Electrostatic chuck is a key component in semiconductor equipment and is widely used in processes such as ion implantation, dry etching, chemical vapor deposition and physical vapor deposition. The traditional electrostatic chuck structure consists of a metal substrate, an upper dielectric layer, a lower dielectric layer and an electrode layer therebetween. The upper dielectric layer and the lower dielectric layer are usually made of ceramic materials, and there are two main manufacturing processes: plasma spraying and high-temperature sintering. Sintered ceramics have a high density and have excellent resistance to plasma erosion and voltage resistance, but their manufacturing process is complex and costly. In view of this, a new electrostatic chuck structure and its manufacturing process are designed to solve the above problems and improve its voltage resistance and insulation performance. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a high insulation resistance, high withstand voltage electrostatic chuck and a preparation method thereof, which has a reasonable structure, a simple process and a low cost.

[0004] In order to solve the above technical problems, the technical solution of the present invention is:

[0005] In one aspect, the present invention discloses an electrostatic chuck, comprising:

[0006] A metal substrate layer, wherein the metal substrate layer is made of metal or alloy;

[0007] a lower dielectric layer, the lower dielectric layer being disposed on the metal substrate layer;

[0008] an upper dielectric layer, the upper dielectric layer being disposed on the lower dielectric layer;

[0009] The side dielectric layer includes a first side dielectric layer arranged on the outer wall of the metal substrate layer, a second side dielectric layer arranged on the outer wall of the lower dielectric layer, and a third dielectric layer arranged on the outer wall of the upper dielectric layer, so as to protect the upper dielectric layer and the lower dielectric layer and repair them after damage.

[0010] Preferably, the thickness of the lower dielectric layer is 0.2 mm to 0.5 mm, and the preparation material of the lower dielectric layer includes aluminum oxide, yttrium oxide, and aluminum nitride. The lower dielectric layer is manufactured by a plasma spraying process and then sealed with a sealing agent to improve its voltage resistance and insulation performance.

[0011] Preferably, the thickness of the upper dielectric layer is 0.2 mm to 0.5 mm, and the preparation material of the upper dielectric layer includes aluminum oxide and yttrium oxide. The upper dielectric layer is manufactured by plasma spraying to improve its voltage resistance and insulation performance.

[0012] Preferably, the thickness of the first side dielectric layer, the second side dielectric layer, and the third side dielectric layer are all 0.2 mm to 1 mm, the materials for making the first side dielectric layer, the second side dielectric layer, and the third side dielectric layer are aluminum oxide and yttrium oxide, and the first side dielectric layer, the second side dielectric layer, and the third side dielectric layer are all made by plasma spraying to ensure their voltage resistance and insulation performance.

[0013] Another aspect of the present invention discloses a method for preparing the electrostatic chuck as described above, the method comprising the following steps:

[0014] S1: manufacturing the metal substrate layer by machining and welding processes, and leaving a water channel, a lift-pin hole, a helium hole and a threaded hole in the metal substrate layer;

[0015] S2: manufacturing the lower dielectric layer by machining, machining the lower dielectric layer to a corresponding size, and leaving lift-pin holes and helium holes in the lower dielectric layer;

[0016] S3: sandblasting the upper surface of the metal substrate layer;

[0017] S4: forming the lower dielectric layer on the upper surface of the metal substrate layer by a plasma spraying process;

[0018] S5: performing sealing treatment on the lower dielectric layer;

[0019] S6: performing sandblasting on the upper surface of the lower dielectric layer;

[0020] S7: forming an upper dielectric layer on the lower dielectric layer by a plasma spraying process;

[0021] S8: forming a side dielectric layer on the side of the metal substrate and the dielectric layer by a plasma spraying process.

[0022] Preferably, in step S3, the upper surface of the metal substrate layer is sandblasted, and in step S6, the upper surface of the lower dielectric layer is sandblasted. The sandblasting material used in the sandblasting is white corundum with a mesh size of 40 to 100. The surface roughness of the metal substrate layer after sandblasting is greater than 3 μm, so as to prepare the lower dielectric layer on the upper surface of the metal substrate layer and improve the density. After sandblasting, the surface roughness of the lower dielectric layer is greater than 3 μm.

[0023] Preferably, the plasma spraying in step S4, step S7 and step S8 all uses Ar as carrier gas with a pressure of 40-60 psi, so that the spraying is more uniform and the coating is more delicate.

[0024] Preferably, in step S5, the lower dielectric layer is sealed, and the sealing agent is any one of a silicate sealing agent, an aluminate sealing agent, a mineral filler, a polymer-modified inorganic sealing agent, and a ceramic sealing agent.

[0025] The above technical solution has the following beneficial effects:

[0026] The electrostatic chuck structure and the manufacturing method thereof of the present application are that the lower dielectric layer and the upper dielectric layer are manufactured by plasma spraying process, the lower dielectric layer is sealed by a sealing agent, and then the upper dielectric layer is melt-sprayed, which improves the withstand voltage and insulation performance of the dielectric layer, thereby effectively ensuring the use requirements of the electrostatic chuck;

[0027] The plasma spraying process is used to reduce the complexity of the process and save costs. At the same time, spraying the first side dielectric layer, the second side dielectric layer, and the third side dielectric layer on the side can effectively insulate and is easy to repair when damaged by collision. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of the electrostatic chuck of the present invention. DETAILED DESCRIPTION

[0029] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] refer to Figure 1 In one aspect, the present invention discloses an electrostatic chuck, comprising:

[0031] The metal substrate layer 1 is made of metal or alloy, such as aluminum, aluminum alloy, or stainless steel. The metal substrate layer 1 includes a power supply part, a water channel, a lift-pin hole, a helium hole, and a threaded hole. Various structures are provided. The threaded hole is convenient for installation, so that the electrostatic chuck has the functions of support and heat dissipation;

[0032] A lower dielectric layer 2, wherein the lower dielectric layer 2 is disposed on the metal substrate layer 1;

[0033] An upper dielectric layer 3, the upper dielectric layer 3 is arranged on the lower dielectric layer 2;

[0034] Side dielectric layers, the side dielectric layers include a first side dielectric layer 4 disposed on the outer side wall of the metal substrate layer 1, a second side dielectric layer 5 disposed on the outer side wall of the lower dielectric layer 2, and a third dielectric layer 6 disposed on the outer side wall of the upper dielectric layer 3, so as to protect the upper dielectric layer 3 and the lower dielectric layer 2 and facilitate repair after damage;

[0035] The thickness of the lower dielectric layer 2 is 0.2 mm or 0.5 mm. In other implementations of the present embodiment, the thickness of the lower dielectric layer 2 is 0.35 mm. The preparation material of the lower dielectric layer 2 includes a mixture of aluminum oxide, yttrium oxide, and aluminum nitride or any one of the three. The lower dielectric layer 2 is made by a plasma spraying process and then sealed with a sealing agent to improve its withstand voltage and insulation performance.

[0036] The thickness of the upper dielectric layer 3 is 0.2 mm or 0.5 mm. In other implementations of the present embodiment, the thickness of the upper dielectric layer 3 is 0.35 mm. The preparation material of the upper dielectric layer 3 includes aluminum oxide, yttrium oxide or a mixture of the two. The upper dielectric layer 3 is made by plasma spraying to improve its withstand voltage and insulation performance.

[0037] The thickness of the first side dielectric layer 4 is 0.2 mm or 1 mm, the thickness of the second side dielectric layer 5 is 0.2 mm or 1 mm, and the thickness of the third side dielectric layer is 0.2 mm or 1 mm. In other implementations of this embodiment, the thickness of the first side dielectric layer 4 is 0.6 mm, the thickness of the second side dielectric layer 5 is 0.5 mm, and the thickness of the third side dielectric layer is 0.7 mm. The materials for making the first side dielectric layer 4, the second side dielectric layer 5, and the third side dielectric layer are aluminum oxide and yttrium oxide. The first side dielectric layer 4, the second side dielectric layer 5, and the third side dielectric layer are ceramic layers made by plasma spraying to ensure their voltage resistance and insulation performance; when the first side dielectric layer 4, the second side dielectric layer 5, and the third side dielectric layer are made by plasma spraying, the diameters of the upper dielectric layer 3, the lower dielectric layer 2, and the metal substrate layer 1 can be the same, so that the first side dielectric layer 4, the second side dielectric layer 5, and the third side dielectric layer are prepared together;

[0038] Another aspect of the present invention discloses a method for preparing an electrostatic chuck, which is used to prepare the above-mentioned electrostatic chuck, and the preparation method comprises the following steps:

[0039] S1: The metal substrate layer 1 is manufactured by machining and welding processes, and a water channel, a lift-pin hole, a helium hole and a threaded hole are left in the metal substrate layer 1. The metal substrate layer 1 is manufactured by a vacuum diffusion welding process. The metal substrate layer 1 adopts a vacuum diffusion welding process. The temperature is low, which can avoid thermal expansion deformation of the material due to internal stress, improve the flatness of the metal substrate layer 1, improve the flatness of other material layers, and thus improve the uniformity of the electrostatic adsorption force of the electrostatic chuck;

[0040] S2: manufacturing the lower dielectric layer 2 by machining, machining the lower dielectric layer 2 to a corresponding size, and leaving lift-pin holes and helium holes in the lower dielectric layer 2;

[0041] S3: sandblasting the upper surface of the metal substrate layer 1, using 40 mesh or 100 mesh white corundum as the sandblasting material, or 70 mesh white corundum, so that the surface roughness of the metal substrate after sandblasting is greater than 3 μm, such as 4 μm, and setting the surface roughness of the metal substrate layer 1 to be greater than 3 μm, so as to facilitate the preparation of the dielectric layer on the upper surface of the metal substrate layer 1, that is, to allow the lower dielectric layer 2 to adhere to the upper surface of the metal substrate layer 1, and also to improve the density;

[0042] S4: The lower dielectric layer 2 is formed on the upper surface of the metal substrate layer 1 by a plasma spraying process. When plasma spraying is performed, Ar is used as a carrier gas, and the pressure is 40 psi or 60 psi, or 50 psi. In this embodiment, Ar is used as a carrier gas in the spraying of the dielectric layer, which can make the spraying more uniform and the coating more delicate.

[0043] S5: performing a sealing treatment on the lower dielectric layer 2, wherein the sealing agent is any one of a silicate sealing agent, an aluminate sealing agent, a mineral filler, a polymer-modified inorganic sealing agent, and a ceramic sealing agent;

[0044] S6: performing sandblasting on the upper surface of the lower dielectric layer 2, wherein the sandblasting material is white corundum with a mesh number of 40 or 100, or white corundum with a mesh number of 70, so that the surface roughness of the lower dielectric layer 2 after sandblasting is greater than 3 μm, such as a surface roughness of 4 μm;

[0045] S7: an upper dielectric layer 3 is formed on the lower dielectric layer 2 by a plasma spraying process. Ar is used as a carrier gas with a pressure of 40 to 60 psi. Ar is used as a carrier gas during the spraying of the upper dielectric layer 3, and the carrier gas pressure is set within a suitable range for spraying, so that the spraying is more uniform and the coating is more delicate.

[0046] S8: A side dielectric layer is formed on the side of the metal substrate and the dielectric layer by a plasma spraying process. Ar is used as a carrier gas with a pressure of 40 to 60 psi during plasma spraying. In this scheme, Ar is used as a carrier gas during spraying of the side dielectric layer, and the carrier gas is selected within a suitable ratio range for spraying, which can make the spraying more uniform and the coating more delicate.

[0047] In the preparation method, the lower dielectric layer 2 and the upper dielectric layer 3 are both made by plasma spraying process, which can avoid the complexity of the process and save costs. At the same time, the first side dielectric layer 4, the second side dielectric layer 5, and the third side dielectric layer are sprayed on the side. The side dielectric layer can effectively insulate and is easy to repair if it is damaged by collision.

[0048] The electrostatic chuck structure and the manufacturing method thereof of the present application, the lower dielectric layer 2 and the upper dielectric layer 3 are manufactured by plasma spraying process, the lower dielectric layer 2 is sealed by a sealing agent, and then the upper dielectric layer 3 is melt-sprayed, which improves the withstand voltage and insulation performance of the dielectric layer, thereby effectively ensuring the use requirements of the electrostatic chuck;

[0049] The plasma spraying process can reduce the complexity of the process and save costs. At the same time, spraying the first side dielectric layer 4, the second side dielectric layer 5, and the third side dielectric layer on the side can effectively insulate and is easy to repair when damaged by collision.

[0050] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

Claims

1. An electrostatic chuck, characterized in that: The electrostatic chuck comprises: A metal substrate layer, wherein the metal substrate layer is made of metal or alloy; a lower dielectric layer, the lower dielectric layer being disposed on the metal substrate layer; an upper dielectric layer, the upper dielectric layer being disposed on the lower dielectric layer; The side dielectric layer includes a first side dielectric layer arranged on the outer wall of the metal substrate layer, a second side dielectric layer arranged on the outer wall of the lower dielectric layer, and a third dielectric layer arranged on the outer wall of the upper dielectric layer, so as to protect the upper dielectric layer and the lower dielectric layer and repair them after damage.

2. An electrostatic chuck according to claim 1, characterized in that: The thickness of the lower dielectric layer is 0.2 mm to 0.5 mm. The preparation material of the lower dielectric layer includes aluminum oxide, yttrium oxide, and aluminum nitride. The lower dielectric layer is made by plasma spraying process and then sealed with a sealing agent to improve its voltage resistance and insulation performance.

3. An electrostatic chuck according to claim 1, characterized in that: The thickness of the upper dielectric layer is 0.2 mm to 0.5 mm. The preparation material of the upper dielectric layer includes aluminum oxide and yttrium oxide. The upper dielectric layer is made by plasma spraying to improve its voltage resistance and insulation performance.

4. An electrostatic chuck according to claim 1, characterized in that: The thickness of the first side dielectric layer, the second side dielectric layer, and the third side dielectric layer are all 0.2 mm to 1 mm. The first side dielectric layer, the second side dielectric layer, and the third side dielectric layer are made of aluminum oxide and yttrium oxide. The first side dielectric layer, the second side dielectric layer, and the third side dielectric layer are all made by plasma spraying to ensure their voltage resistance and insulation performance.

5. A method for preparing an electrostatic chuck according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: S1: manufacturing the metal substrate layer by machining and welding processes, and leaving a water channel, a lift-pin hole, a helium hole and a threaded hole in the metal substrate layer; S2: manufacturing the lower dielectric layer by machining, machining the lower dielectric layer to a corresponding size, and leaving lift-pin holes and helium holes in the lower dielectric layer; S3: sandblasting the upper surface of the metal substrate layer; S4: forming the lower dielectric layer on the upper surface of the metal substrate layer by a plasma spraying process; S5: performing sealing treatment on the lower dielectric layer; S6: performing sandblasting on the upper surface of the lower dielectric layer; S7: forming an upper dielectric layer on the lower dielectric layer by a plasma spraying process; S8: forming a side dielectric layer on the side of the metal substrate and the dielectric layer by a plasma spraying process.

6. The method for preparing an electrostatic chuck according to claim 5, characterized in that: In the step S3, the upper surface of the metal substrate layer is sandblasted, and in the step S6, the upper surface of the lower dielectric layer is sandblasted. The sandblasting material used in the sandblasting is white corundum with a mesh size of 40 to 100. The surface roughness of the metal substrate layer after sandblasting is greater than 3 μm, so as to prepare the lower dielectric layer on the upper surface of the metal substrate layer and improve the density. After sandblasting, the surface roughness of the lower dielectric layer is greater than 3 μm.

7. The method for preparing an electrostatic chuck according to claim 5, characterized in that: The plasma spraying in step S4, step S7 and step S8 all uses Ar as carrier gas with a pressure of 40-60 psi to make the spraying more uniform and the coating more delicate.

8. The method for preparing an electrostatic chuck according to claim 5, characterized in that: In the step S5, the lower dielectric layer is sealed, and the sealing agent is any one of a silicate sealing agent, an aluminate sealing agent, a mineral filler, a polymer-modified inorganic sealing agent, and a ceramic sealing agent.

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