Electrode assembly, preparation method thereof, capacitive coupling plasma discharge cavity and plasma device

Abstract

The invention belongs to the field of plasma devices, and particularly relates to an electrode assembly, a preparation method thereof, a capacitive coupling plasma discharge cavity and a plasma device. The electrode assembly comprises a heating disc, a supporting seat and an electrode, the supporting seat is vertically connected with the heating disc; the supporting seat is in a hollow tubular shape and comprises a tubular supporting seat base body and a first metal conductive layer covering the inner surface of the supporting seat base body. The supporting seat base body is made of a ceramic material; the electrode comprises a first part embedded in the heating disc and a second part located on the center shaft of the supporting base. Parasitic plasmas can be prevented from being generated in the vacuum cavity around the supporting seat, and the process stability is improved.

Description

Technical Field

[0001] This invention belongs to the field of plasma devices, specifically relating to an electrode assembly, its preparation method, a capacitively coupled plasma discharge cavity, and a plasma device. Background Technology

[0002] In capacitively coupled plasma (CCP) discharge cavities used in plasma-enhanced chemical vapor deposition (PECVD) or etching, the plasma between the upper and lower electrodes is useful for wafer processing, but plasma appearing in other unwanted locations is called parasitic plasma. Parasitic plasma can be generated around electrodes where radio frequency (RF) power is applied (ungrounded electrodes, ceramic electrodes) and around the support. Parasitic plasma is more likely to be generated when RF is input from the lower electrode or at high frequencies and high power. The instability of parasitic plasma can affect process stability.

[0003] Therefore, there is an urgent need to develop a capacitively coupled plasma discharge cavity that can avoid the generation of parasitic plasma. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an electrode assembly, its fabrication method, a capacitively coupled plasma discharge cavity, and a plasma device. This invention achieves conductivity of the support by covering the inner surface (atmospheric end) of a ceramic support with a conductive metal layer, thereby achieving grounding and preventing the generation of parasitic plasma in the vacuum cavity surrounding the support, thus avoiding impact on process stability.

[0005] Specifically, the present invention provides an electrode assembly, which includes a heating plate, a support base, and an electrode; the support base is perpendicularly connected to the heating plate; the support base is hollow tubular, and includes a tubular support base body and a first metal conductive layer covering the inner surface of the support base body; the support base body is made of ceramic material; the electrode includes a first part embedded inside the heating plate and a second part located on the central axis of the support base.

[0006] In one or more embodiments, the heating plate is made of ceramic.

[0007] In one or more embodiments, the support base is made of aluminum nitride and / or aluminum oxide.

[0008] In one or more embodiments, the material of the first metallic conductive layer is selected from one or more of aluminum, copper, silver, nickel, and gold.

[0009] In one or more embodiments, the first metal conductive layer is a mesh structure or a dense structure.

[0010] In one or more embodiments, the electrode is made of one or more of stainless steel, aluminum, and molybdenum.

[0011] In one or more embodiments, the first portion of the electrode is made of molybdenum.

[0012] In one or more embodiments, the material of the second portion of the electrode is selected from one or more of stainless steel, nickel, and gold-plated stainless steel.

[0013] In one or more embodiments, the electrode assembly further includes a metal substrate connected to one end of the support base away from the heating plate.

[0014] In one or more embodiments, the heating plate is made of aluminum nitride and / or aluminum oxide.

[0015] In one or more embodiments, the metal substrate is made of aluminum and / or stainless steel.

[0016] In one or more embodiments, the electrode assembly further includes a bend that connects the support and the metal substrate.

[0017] In one or more embodiments, the bent portion extends vertically outward along the central axis of the support.

[0018] In one or more embodiments, the surface of the bent portion away from the heating plate has a second metallic conductive layer.

[0019] In one or more embodiments, the material of the second metallic conductive layer is selected from one or more of aluminum, copper, silver, nickel, and gold.

[0020] In one or more embodiments, the second metal conductive layer is a mesh structure or a dense structure.

[0021] In one or more embodiments, the material of the first metal conductive layer on the inner surface of the support base is the same as or different from the material of the second metal conductive layer on the surface of the bent portion.

[0022] In one or more embodiments, the second metal conductive layer on the surface of the bent portion is made of aluminum or nickel, and the surface of the bent portion away from the heating plate is completely covered by the second metal conductive layer.

[0023] In one or more embodiments, the second metal conductive layer on the surface of the bent portion is made of aluminum or nickel, and the surface of the bent portion away from the heating plate is covered by the second metal conductive layer and an elastic annular seal; the elastic annular seal is located at the end of the second metal conductive layer.

[0024] In one or more embodiments, the second metal conductive layer on the surface of the bent portion is made of copper, silver, or gold, and the surface of the bent portion away from the heating plate is covered by the second metal conductive layer and an elastic annular seal; the elastic annular seal is located at the end of the second metal conductive layer.

[0025] The present invention provides a method for preparing the electrode assembly of the present invention, the method comprising depositing a first metal conductive layer on the inner surface of the support substrate using a chemical or physical method.

[0026] In one or more embodiments, the chemical method is electroless metallization, direct copper plating, thick film metallization, or thin film metallization.

[0027] In one or more embodiments, the physical method is to directly embed a metal sleeve and / or metal grid into the inner surface of the support base.

[0028] The present invention provides a capacitively coupled plasma discharge cavity comprising any of the electrode components described in the present invention.

[0029] The present invention provides a plasma device comprising any of the capacitively coupled plasma discharge cavities described in the present invention. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the capacitively coupled plasma discharge cavity according to some embodiments of the present invention, and a photograph of the electrode assembly portion therein.

[0031] Figure 2 The images show photographs of electrode components in some embodiments of the present invention and schematic diagrams of the heating plate, support base, and bending portion therein.

[0032] Figure 3 This is a cross-sectional view of the heating plate, support base, bending portion, and elastic annular seal in an electrode assembly according to some embodiments of the present invention.

[0033] Figure 4 This is a schematic diagram illustrating the physical method used to prepare electrode components in some embodiments of the present invention.

[0034] Figure 5 This is a parasitic plasma side view of the prior art electrode assembly support accessory of the present invention.

[0035] Figure 6 This is a capacitively coupled plasma discharge cavity (CCP cavity) according to some embodiments of the present invention. 1 is the upper electrode (gas spray plate), 2 is the electrode assembly, 3 is the radio frequency power supply, and 4 is the matching device. Detailed Implementation

[0036] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0037] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0038] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0039] In this document, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0040] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0041] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope defined by the claims.

[0042] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0043] The electrode assembly provided by this invention includes a heating plate, a support base, and electrodes. In this invention, the support base is vertically connected to the bottom of the heating plate.

[0044] In this invention, the heating plate can be a solid structure. In this invention, the heating plate can be made of ceramic material. In this invention, the ceramic material can be aluminum nitride and / or aluminum oxide. In this invention, the heating plate can be made of aluminum nitride and / or aluminum oxide.

[0045] In this invention, the support base is hollow and tubular, comprising a tubular support base substrate and a first conductive metal layer covering the inner surface (atmospheric end) of the support base substrate. In this invention, the support base substrate can be made of ceramic. In this invention, the support base substrate can be made of aluminum nitride and / or aluminum oxide. In this invention, the first conductive metal layer on the inner surface of the support base substrate can be made of one or more materials selected from aluminum, copper, silver, nickel, and gold. In this invention, the first conductive metal layer on the inner surface of the support base substrate can have a mesh structure or a dense structure.

[0046] In this invention, the electrode may include a first portion embedded inside the heating plate and a second portion located on the central axis of the support. In this invention, the first portion of the electrode may be made of molybdenum. Molybdenum is heat-resistant and has a suitable coefficient of thermal expansion. In this invention, the second portion of the electrode may be made of one or more materials selected from stainless steel, nickel, and gold-plated stainless steel.

[0047] In this invention, the electrode assembly further includes a metal substrate connected to the end of the support base away from the heating plate. In this invention, the metal substrate can be made of stainless steel and / or aluminum.

[0048] In this invention, the electrode assembly further includes a bent portion connecting the support base and the metal substrate. The bent portion can extend vertically outward along the central axis of the support base. The surface of the bent portion away from the heating plate has a second conductive metal layer. The bent portion can also be metallized to connect with the grounded metal base, achieving good grounding and thus preventing the generation of parasitic plasma. The material of the second conductive metal layer on the surface of the bent portion can be one or more selected from aluminum, copper, silver, nickel, and gold. The second conductive metal layer on the surface of the bent portion can be a mesh structure or a dense structure. The material of the first conductive metal layer on the inner surface of the support base substrate can be the same as or different from the material of the second conductive metal layer on the surface of the bent portion.

[0049] In this invention, the second conductive metal layer on the surface of the bent portion is made of aluminum or nickel, and the surface of the bent portion away from the heating plate can be completely covered by the second conductive metal layer. Alternatively, the second conductive metal layer on the surface of the bent portion is made of aluminum or nickel, and the surface of the bent portion away from the heating plate can be covered by the second conductive metal layer and an elastic annular seal; the elastic annular seal is located at the end of the second conductive metal layer. Another option is to use copper, silver, or gold as the material for the second conductive metal layer on the surface of the bent portion. This is because copper and silver have excessively high conductivity, and if small particles fall onto the microelectronic devices on the wafer surface, they can easily cause short circuits and damage. Therefore, copper, silver, or gold are incompatible, while aluminum and nickel are compatible materials for the inner wall of the cavity. Since the bent portion is partially conductive, the elastic annular seal can isolate the conductive metal layer from the vacuum. In this invention, the elastic annular seal can be an O-ring.

[0050] This invention provides a method for preparing the electrode assembly of the present invention, the method comprising depositing a first metallic conductive layer on the inner surface of the support substrate using a chemical or physical method. In this invention, the chemical method can be electroless metallization, direct copper plating metallization, thick-film metallization, or thin-film metallization. Specifically, electroless metallization equipment is simple, low-cost, and easy to mass-produce, but its bonding strength is low; direct copper plating metallization has good thermal conductivity, high bonding strength, and good mechanical properties, and is easy to mass-produce, but the oxidation process conditions of ceramics and Cu foil are difficult to control; thick-film metallization process is simple and can achieve small-scale production, but the transition layer is thick, and the adhesive can affect the thermal conductivity of the substrate after metallization; thin-film metallization produces a uniform metallized film layer, allows for fine processing, and has high bonding strength, but requires large equipment investment and is difficult to mass-produce. In this invention, the physical method can be to directly embed a metal sleeve and / or metal grid into the inner surface of the support substrate.

[0051] The present invention provides a capacitively coupled plasma discharge cavity (CCP cavity) including the electrode assembly of the present invention. The CCP cavity includes an upper electrode (gas spray plate), the electrode assembly of the present invention, a radio frequency power supply, and a matching device (feeding in radio frequency power).

[0052] The present invention provides a plasma device comprising the capacitively coupled plasma discharge cavity of the present invention.

[0053] Compared with the prior art, the present invention has the following beneficial technical effects: (1) The present invention achieves conductive treatment of the support by covering the inner surface of the ceramic support with a metal conductive layer, thereby achieving grounding and avoiding the generation of parasitic plasma in the vacuum cavity around the support (or other similar structures, such as SHD (Showerhead)), thus avoiding affecting the stability of the process; (2) The metal conductive layer of the present invention is located at the atmospheric end of the support, does not affect the plasma, is not damaged by the plasma, and is not polluted.

[0054] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. Unless otherwise stated, the methods, reagents, and materials used in the embodiments are conventional methods, reagents, and materials in the art. The raw material compounds in the embodiments are all commercially available.

[0055] Example 1

[0056] The capacitively coupled plasma discharge cavity in this embodiment (e.g.) Figure 6 As shown), the CCP cavity includes an upper electrode, an electrode assembly (in this embodiment), an RF power supply, and a matching unit. The electrode assembly includes a heating plate, a support base, electrodes, a metal substrate, and a bent portion. The support base is vertically connected to the heating plate. The heating plate is made of aluminum nitride ceramic. The support base is hollow and tubular, including a tubular support base body and a first metal conductive layer covering the inner surface of the support base body. The support base body is made of aluminum nitride ceramic. The first metal conductive layer is made of copper and has a uniform, dense thin film structure. The electrodes are embedded in the heating plate. The device consists of a first internal part and a second part located on the central axis of the support base. The first part of the electrode is a molybdenum mesh, and the second part of the electrode is a nickel rod. The support base is connected to a metal substrate at the end away from the heating plate. The metal substrate is made of aluminum. A bent portion is used to connect the support base and the metal substrate. The bent portion extends vertically outward along the central axis of the support base. The surface of the bent portion away from the heating plate has a second metal conductive layer. The second metal conductive layer is a uniform and dense thin film structure. The second metal conductive layer is made of aluminum, and the surface of the bent portion away from the heating plate is completely covered by the second metal conductive layer.

[0057] Example 2

[0058] The capacitively coupled plasma discharge cavity in this embodiment (e.g.) Figure 6As shown), the CCP cavity includes an upper electrode, an electrode assembly (in this embodiment), an RF power supply, and a matching unit. The electrode assembly (in this embodiment) includes a heating plate, a support base, electrodes, a metal substrate, and a bent portion. The support base is perpendicularly connected to the heating plate. The heating plate is made of aluminum nitride ceramic. The support base is hollow and tubular, including a tubular support base body and a first metal conductive layer covering the inner surface of the support base body. The support base body is made of aluminum nitride ceramic. The first metal conductive layer is made of copper and has a uniform, dense thin film structure. The electrodes include a first portion embedded inside the heating plate and a second portion located on the central axis of the support base. The electrode consists of two parts: a first part is a molybdenum mesh, and a second part is a nickel rod; a metal substrate, made of aluminum, is connected to the end of the support base away from the heating plate; a bent portion is used to connect the support base and the metal substrate, extending vertically outward along the central axis of the support base; the surface of the bent portion away from the heating plate has a second conductive metal layer, which is a uniform and dense thin film structure; the second conductive metal layer is made of copper; the surface of the bent portion away from the heating plate is covered by the second conductive metal layer and an elastic annular seal; the elastic annular seal is located at the end of the second conductive metal layer and is an O-ring.

[0059] The capacitively coupled plasma discharge cavity in this embodiment avoids the generation of parasitic plasma in the vacuum cavity around the support, thus preventing it from affecting process stability; at the same time, the metal conductive layer is located at the atmospheric end of the support, so it does not affect the plasma, is not damaged by the plasma, and is free from pollution.

Claims

1. An electrode assembly, characterized in that, The electrode assembly includes a heating plate, a support base, and electrodes; The support base is perpendicularly connected to the heating plate; The support base is in the shape of a hollow tube, and includes a tubular support base body and a first metal conductive layer covering the inner surface of the support base body; the support base body is made of ceramic material. The electrode comprises a first portion embedded inside the heating plate and a second portion located on the central axis of the support.

2. The electrode assembly as described in claim 1, characterized in that, The electrode assembly has one or more of the following characteristics: The heating plate is made of ceramic. The material of the support base is aluminum nitride and / or aluminum oxide; The material of the first metallic conductive layer is selected from one or more of aluminum, copper, silver, nickel, and gold; The first metal conductive layer has a mesh structure or a dense structure; The first part of the electrode is made of molybdenum; The material of the second part of the electrode is selected from one or more of stainless steel, nickel, and gold-plated stainless steel; The electrode assembly also includes a metal substrate connected to the end of the support base away from the heating plate.

3. The electrode assembly as described in claim 2, characterized in that, The electrode assembly has one or more of the following characteristics: The heating plate is made of aluminum nitride and / or aluminum oxide. The metal substrate is made of aluminum and / or stainless steel; The electrode assembly also includes a bent portion connecting the support and the metal substrate.

4. The electrode assembly as described in claim 3, characterized in that, The bent portion extends vertically outward along the central axis of the support; and / or The surface of the bent portion away from the heating plate has a second metallic conductive layer.

5. The electrode assembly as described in claim 4, characterized in that, The electrode assembly has one or more of the following characteristics: The material of the second metallic conductive layer is selected from one or more of aluminum, copper, silver, nickel, and gold; The second metal conductive layer has a mesh structure or a dense structure; The material of the first metal conductive layer on the inner surface of the support base may be the same as or different from the material of the second metal conductive layer on the surface of the bent portion.

6. The electrode assembly as claimed in claim 5, characterized in that, The second conductive metal layer on the surface of the bent portion is made of aluminum or nickel, and the surface of the bent portion away from the heating plate is completely covered by the second conductive metal layer; or The second metal conductive layer on the surface of the bent portion is made of aluminum or nickel, and the surface of the bent portion away from the heating plate is covered by the second metal conductive layer and an elastic annular seal; the elastic annular seal is located at the end of the second metal conductive layer; or The second metal conductive layer on the surface of the bent portion is made of copper, silver or gold. The surface of the bent portion away from the heating plate is covered by the second metal conductive layer and an elastic annular seal. The elastic annular seal is located at the end of the second metal conductive layer.

7. A method for preparing the electrode assembly according to any one of claims 1-6, characterized in that, The method includes setting a first metallic conductive layer on the inner surface of the support base using chemical or physical methods.

8. The method as described in claim 7, characterized in that, The chemical method is electroless metallization, direct copper plating, thick film metallization, or thin film metallization; or The physical method involves directly embedding a metal sleeve and / or metal grid into the inner surface of the support base.

9. A capacitively coupled plasma discharge cavity comprising the electrode assembly of any one of claims 1-6.

10. A plasma device comprising the capacitively coupled plasma discharge cavity of claim 9.

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