Plasma processing device

Abstract

A plasma processing device comprises: a reaction chamber body, a plasma channel plate is arranged on the top of the reaction chamber body, and the plasma channel plate comprises: a plasma channel plate body; a channel plate positioning piece surrounding the side of the plasma channel plate body; a conductive and heat conductive ring located between the channel plate positioning piece and the top wall of the reaction chamber body; and a plasma generating unit located above the plasma channel plate body. The plasma processing device can avoid the problem of damage to the plasma channel plate under high temperature conditions and poor grounding of the plasma channel plate.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to a plasma processing device. Background Art

[0002] In semiconductor manufacturing, multiple processes are involved, and each process is completed by certain equipment and processes. Among them, plasma reactions are often used for chemical and physical deposition, etching, and photoresist ashing removal of semiconductor wafers and other substrates. Commonly used plasma sources include ICP, CCP, and microwave generation methods. For the photoresist ashing removal process, the following processes are usually carried out: 1) Spinning the photoresist onto the semiconductor substrate; 2) Targetedly exposing the photoresist layer to light for development, forming a specific photoresist pattern on the top of the semiconductor substrate, that is, part of the semiconductor substrate to be processed is exposed; 3) Etching or high-dose ion implantation into the exposed part of the semiconductor substrate; 4) Removing the photoresist that acts as a mask during etching or high-dose ion implantation, which is what we call the photoresist ashing removal process. Typically, the photoresist ashing removal process includes two types: photoresist mask removal after the etching process; photoresist mask removal after the high-dose ion implantation process. For the photoresist ashing removal process, it is usually not desirable for the high-energy ions in the plasma to directly react with the photoresist, but rather it is desirable for a high-temperature chemical reaction to occur between the chemically active free radical intermediates in the plasma and the photoresist.

[0003] Generally, the photoresist ashing reaction chamber consists of a plasma generating chamber and a wafer processing chamber. In order to prevent the high-energy ions in the plasma from causing irreversible physical bombardment damage (Plasma Induced Damage) to the wafer during the photoresist ashing removal process, a plasma channel plate is usually installed between the plasma generating chamber and the wafer processing chamber. The plasma channel plate is a porous disc structure, and neutral chemically active groups can pass through freely, while charged ions are quenched (Quench) after hitting the grid. The neutral chemically active groups that pass through the plasma channel plate undergo a high-temperature chemical reaction with the wafer on the high-temperature wafer tray to remove residual photoresist on the wafer surface.

[0004] However, the plasma channel plate in the prior art is easily damaged under high temperature conditions. Summary of the invention

[0005] The problem solved by the present invention is to provide a plasma processing device, which can avoid the problem of damage of a plasma channel plate under high temperature conditions and poor grounding of the plasma channel plate.

[0006] In order to solve the above technical problems, the present invention provides a plasma processing device, comprising: a reaction chamber body, a plasma channel plate is arranged on the top of the reaction chamber body, and the plasma channel plate comprises: a plasma channel plate body; a channel plate positioning piece surrounding the side of the plasma channel plate body; a conductive and heat-conductive ring located between the channel plate positioning piece and the top wall of the reaction chamber body; and a plasma generating unit located above the plasma channel plate body.

[0007] Optionally, the surface hardness of the electrically conductive and thermally conductive ring is smaller than the hardness of the channel plate positioning member.

[0008] Optionally, the material of the electrically conductive and thermally conductive ring is graphite.

[0009] Optionally, the conductive and heat-conductive ring includes a conductive and heat-conductive ring body, a first film layer located on the top of the conductive and heat-conductive ring body, and a second film layer located on the bottom of the conductive and heat-conductive ring body; the first film layer, the conductive and heat-conductive ring body and the second film layer are arranged along the central axis of the conductive and heat-conductive ring body; the first film layer is in contact with the channel plate positioning piece, and the second film layer is in contact with the top wall of the reaction chamber body; the hardness of the conductive and heat-conductive ring body is greater than the hardness of the first film layer and the second film layer, and the hardness of the first film layer and the second film layer is less than the hardness of the channel plate positioning piece.

[0010] Optionally, the material of the electrically conductive and thermally conductive ring body is aluminum, and the material of the first film layer and the second film layer is graphite.

[0011] Optionally, the thickness of the electrically conductive and thermally conductive ring is 0.08 mm to 0.15 mm.

[0012] Optionally, the resistivity of the conductive and thermally conductive ring is less than or equal to 1×10 -5 Ω*m; the thermal conductivity of the conductive and thermally conductive ring is greater than or equal to 100W / (m*K).

[0013] Optionally, the electrically conductive and thermally conductive ring is grounded.

[0014] Optionally, it further includes: a cooling system, the cooling system including: a cold source; a channel located in the top wall of the reaction chamber body, the channel being connected to the cold source through a pipeline.

[0015] Optionally, the channel plate positioning piece has a plurality of first positioning holes passing through the channel plate positioning piece; the conductive and thermally conductive ring has a plurality of second positioning holes passing through the conductive and thermally conductive ring, and the first positioning holes and the second positioning holes are connected; the plasma processing device also includes: a fastener, which fastens the channel plate positioning piece and the conductive and thermally conductive ring to the top wall of the reaction chamber body, and the fastener is located in the first positioning hole and the second positioning hole.

[0016] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0017] The plasma processing device provided by the technical solution of the present invention includes: an electrically conductive heat-conducting ring located between the channel plate positioning member and the top wall of the reaction chamber body. Since the hardness of the electrically conductive heat-conducting ring is less than that of the channel plate positioning member, the electrically conductive heat-conducting ring is flexible relative to the channel plate positioning member. After the channel plate positioning member and the electrically conductive heat-conducting ring are fastened to the top wall of the reaction chamber body, the channel plate positioning member and the top wall of the reaction chamber body can be well contacted, and the contact area between the channel plate positioning member and the top wall of the reaction chamber body is increased, thereby improving the heat conduction effect between the channel plate positioning member and the top wall of the reaction chamber body. Therefore, when the plasma channel plate is under high temperature conditions, the heat energy of the plasma channel plate body can be conducted to the top wall of the reaction chamber body through the channel plate positioning member and the electrically conductive heat-conducting ring, avoiding large stress on the plasma channel plate body at high temperature, thereby ensuring good flatness of the plasma channel plate body and avoiding damage to the plasma channel plate. Secondly, since the contact area between the channel plate positioning piece and the top wall of the reaction chamber body is increased, the contact resistance between the channel plate positioning piece and the top wall of the reaction chamber body is reduced, thereby enhancing the conductive effect between the channel plate positioning piece and the reaction chamber body, and increasing the contact capacitance between the channel plate positioning piece and the reaction chamber body, so that the radio frequency current can enter the reaction chamber body and then to the ground more smoothly from the plasma channel plate body, thereby enhancing the grounding effect of the plasma channel plate, and increasing the quenching speed of the plasma channel plate body on the charged particles in the plasma, thereby improving the filtering effect of the plasma channel plate body. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the cross-sectional structure of a plasma processing device;

[0019] Figure 2 is a schematic cross-sectional structural diagram of a plasma processing device in one embodiment of the present invention;

[0020] Figure 3 1 is a top view of a plasma channel plate assembly in one embodiment of the present invention. DETAILED DESCRIPTION

[0021] As described in the background art, the plasma channel plate in the prior art is easily damaged under high temperature conditions and the plasma channel plate has a problem of poor grounding.

[0022] Typical structures such as Figure 1As shown, the plasma processing device includes: a wafer processing chamber 3; a wafer tray 1; a wafer 2; a plasma channel plate body 4; a channel plate positioning member 5; a plasma channel plate fixing screw 6; a plasma generator 7; a plasma generating chamber 8; an air inlet 9; and an air outlet 10.

[0023] Usually, the plasma channel plate body 4 and the channel plate positioning member 5 are an integrated structure, and the channel plate positioning member 5 is fixed to the cavity top wall of the wafer processing chamber 3 by the plasma channel plate fixing screw 6 and is kept grounded (taking Al material as an example). The plasma channel plate body 4 can usually be made of a conductive material, such as Al, or an insulating material, such as ceramics. However, in order to increase the filtering effect of the plasma channel plate body 4 on charged particles in the plasma, the plasma channel plate body 4 and the channel plate positioning member 5 are often made of a conductive material and are grounded.

[0024] After research, it was found that this installation and fixing method has the following problems:

[0025] 1. The problem of releasing the high-temperature thermal deformation stress of the plasma channel plate body 4. Specifically, the high-density plasma in the plasma generator 7 will continue to heat the plasma channel plate body 4. Due to the high hardness of the channel plate positioning member 5, it is difficult for the channel plate positioning member 5 to fully contact the top wall of the wafer processing chamber 3. The contact area between the channel plate positioning member 5 and the top wall of the wafer processing chamber 3 is small (point contact is presented at the microscopic level). Therefore, the plasma channel plate body 4 cannot transfer heat to the upper cavity of the wafer processing chamber 3 in time, and then the plasma channel plate body 4 will generate thermal deformation stress due to high temperature. Usually, tensile stress appears on the top surface of the plasma channel plate body 4, and compressive stress appears on the bottom surface of the plasma channel plate body 4, resulting in the central surface of the plasma channel plate body 4 bending toward the plasma generator 7. When the temperature of the plasma channel plate body 4 is heated by plasma from 20°C to 200°C, the radial expansion of the plasma channel plate body 4 reaches about 2mm; in order to release this expansion, the bending amount of the grid surface of the plasma channel plate body 4 toward the plasma direction will reach 2mm. During the cyclic expansion-contraction process of "low temperature-high temperature-low temperature-high temperature-...", the center of the plasma channel plate body 4 may be slightly broken and damaged to produce debris, which in turn leads to particle contamination of the wafer.

[0026] 2. The problem of insufficient grounding of the plasma channel plate main body 4. Specifically, since the contact area between the channel plate positioning member 5 and the top wall of the wafer processing chamber 3 is small, the contact resistance between the channel plate positioning member 5 and the top wall of the wafer processing chamber 3 is large and the contact capacitance is small, that is, the grounding effect of the plasma channel plate main body 4 is not ideal, which makes the quenching speed of the charged particles in the plasma by the plasma channel plate main body 4 insufficient.

[0027] In order to solve the above technical problems, the present invention provides a plasma processing device, comprising: a reaction chamber body, a plasma channel plate is arranged on the top of the reaction chamber body, and the plasma channel plate comprises: a plasma channel plate body; a channel plate positioning piece surrounding the side of the plasma channel plate body; a conductive and heat conductive ring located between the channel plate positioning piece and the top wall of the reaction chamber body; and a plasma generating unit located above the plasma channel plate body. The plasma processing device can avoid the problem of damage to the plasma channel plate under high temperature conditions and poor grounding of the plasma channel plate.

[0028] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] An embodiment of the present invention provides a plasma processing device, Figure 2 and Figure 3 , comprising: a reaction chamber body 30, a plasma channel plate is arranged on the top of the reaction chamber body 30; the plasma channel plate comprises: a plasma channel plate body 40; a channel plate positioning piece 50 located at the side of the plasma channel plate body 40, a conductive and thermal conductive ring 60 located between the channel plate positioning piece 50 and the top wall of the reaction chamber body 30; and a plasma generating unit located above the plasma channel plate body 40.

[0030] The surface hardness of the electrically conductive and thermally conductive ring 60 is smaller than the hardness of the channel plate positioning member 50 .

[0031] In one embodiment, the conductive and thermally conductive ring 60 is made of graphite, so that the conductive and thermally conductive ring 60 has better electrical and thermal conductivity.

[0032] In another embodiment, the conductive heat-conducting ring 60 includes a conductive heat-conducting ring body, a first film layer located at the top of the conductive heat-conducting ring body, and a second film layer located at the bottom of the conductive heat-conducting ring body; the first film layer, the conductive heat-conducting ring body, and the second film layer are arranged along the central axis of the conductive heat-conducting ring body; the first film layer is in contact with the channel plate positioning member, and the second film layer is in contact with the top wall of the reaction chamber body. The hardness of the conductive heat-conducting ring body is greater than that of the first film layer and the second film layer. Specifically, the material of the conductive heat-conducting ring body is aluminum, and the material of the first film layer and the second film layer is graphite.

[0033] Since the hardness of the conductive heat-conducting ring body is greater than that of the first film layer and the second film layer, the conductive heat-conducting ring 60 body has a greater hardness, so that the conductive heat-conducting ring 60 is not easy to have a self-brittle crack problem when being fixed. Since the hardness of the first film layer and the second film layer is relatively small, the hardness of the first film layer and the second film layer is less than the hardness of the channel plate positioning member 50, so that the contact area between the first film layer and the channel plate positioning member 50 is larger, and the contact area between the second film layer and the top wall of the reaction chamber body 30 is larger.

[0034] In a specific embodiment, the thickness of the electrically conductive and thermally conductive ring 60 is 0.08 mm to 0.15 mm.

[0035] The resistivity of the conductive and thermally conductive ring 60 is less than or equal to 1×10 -5 The thermal conductivity of the conductive and thermally conductive ring 60 is greater than or equal to 100 W / (m*K).

[0036] In this embodiment, the conductive heat-conducting ring 60 is grounded. Specifically, the reaction chamber body 30 is grounded, and the material of the reaction chamber body 30 in contact with the conductive heat-conducting ring 60 is metal, such as aluminum. The conductive heat-conducting ring 60 is electrically connected to the reaction chamber body 30, so that the conductive heat-conducting ring 60 is grounded.

[0037] The plasma channel plate body 40 is a disk-shaped porous structure.

[0038] In this embodiment, the channel plate positioning member 50 and the plasma channel plate body 40 are made of metal, such as aluminum.

[0039] The plasma channel plate body 40 and the channel plate positioning member 50 are an integrated structure.

[0040] The plasma processing device further comprises: a cooling system, the cooling system comprising: a cooling source; a channel located in the top wall of the reaction chamber body, the channel being connected to the cooling source through a pipeline. Specifically, the channel has a liquid inlet 60 and a liquid outlet 13 .

[0041] In this embodiment, the channel plate positioning member 50 has a plurality of first positioning holes 51 penetrating the channel plate positioning member 50 ; the conductive and thermally conductive ring 60 has a plurality of second positioning holes 61 penetrating the conductive and thermally conductive ring 60 , and the first positioning holes and the second positioning holes are connected.

[0042] The plasma processing device further includes a fastener 70, which fastens the channel plate positioning member 50 and the conductive and thermally conductive ring 60 to the top wall of the reaction chamber body 30, and the fastener 70 is located in the first positioning hole and the second positioning hole. The fastener 70 may be a screw, for example.

[0043] The plasma processing device further includes: a wafer clamping platform 14 located in the reaction chamber body 30 , the surface of the wafer clamping platform 14 is suitable for placing the wafer 20 ; the central axis of the plasma channel plate body 40 coincides with the central axis of the wafer clamping platform 14 .

[0044] The plasma generating unit comprises: a reaction chamber medium tube 90 and a radio frequency antenna 80 located on the side wall of the reaction chamber medium tube 90. The top of the reaction chamber medium tube 90 has an air inlet 15. The bottom of the reaction chamber body 30 also has an air outlet 11.

[0045] The RF antenna 80 excites the gas in the medium tube 90 entering the reaction chamber to generate plasma. The charged particles (including ions and electrons) in the plasma will be filtered out by the plasma channel plate body 40. The charged ions will be quenched after hitting the surface wall of the plasma channel plate body 40. The neutral chemically active groups in the plasma will freely pass through the plasma channel plate body 40 into the reaction chamber body 30 to reach the surface of the wafer 20. The neutral chemically active groups that pass through the plasma channel plate body 40 react with the wafer 20 on the wafer clamping platform 14. Specifically, a high-temperature chemical reaction is performed, for example, residual photoresist on the surface of the wafer 20 can be removed.

[0046] The plasma processing device provided in this embodiment includes: a conductive heat-conducting ring located between the channel plate positioning member and the top wall of the reaction chamber body. Since the hardness of the conductive heat-conducting ring is less than that of the channel plate positioning member, the conductive heat-conducting ring is flexible relative to the channel plate positioning member. After the channel plate positioning member and the conductive heat-conducting ring are fastened to the top wall of the reaction chamber body, the channel plate positioning member and the top wall of the reaction chamber body can be well contacted, and the contact area between the channel plate positioning member and the top wall of the reaction chamber body is increased, thereby improving the heat conduction effect between the channel plate positioning member and the top wall of the reaction chamber body, thereby improving the heat conduction effect between the channel plate positioning member and the top wall of the reaction chamber body. Therefore, when the plasma channel plate is under high temperature conditions, the heat energy of the plasma channel plate body can be conducted to the top wall of the reaction chamber body through the channel plate positioning member and the conductive heat-conducting ring, avoiding large stress on the plasma channel plate body at high temperature, thereby ensuring good flatness of the plasma channel plate body and avoiding damage to the plasma channel plate. Secondly, since the contact area between the channel plate positioning piece and the top wall of the reaction chamber body is increased, the contact resistance between the channel plate positioning piece and the top wall of the reaction chamber body is reduced, thereby enhancing the conductive effect between the channel plate positioning piece and the reaction chamber body, and increasing the contact capacitance between the channel plate positioning piece and the reaction chamber body, so that the radio frequency current can enter the reaction chamber body and then to the ground more smoothly from the plasma channel plate body, thereby enhancing the grounding effect of the plasma channel plate, and increasing the quenching speed of the plasma channel plate body on the charged particles in the plasma, thereby improving the filtering effect of the plasma channel plate body.

[0047] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A plasma processing device, characterized in that: include: A reaction chamber body, wherein a plasma channel plate is disposed on the top of the reaction chamber body, and the plasma channel plate comprises: a plasma channel plate body; a channel plate positioning member surrounding the side of the plasma channel plate body; an electrically conductive and heat-conductive ring located between the channel plate positioning piece and the top wall of the reaction chamber body, wherein the surface hardness of the electrically conductive and heat-conductive ring is less than the hardness of the channel plate positioning piece; a plasma generating unit located above the plasma channel plate body; The material of the electrically conductive and thermally conductive ring is graphite.

2. The plasma processing device according to claim 1, characterized in that: The conductive and heat-conductive ring comprises a conductive and heat-conductive ring body, a first film layer located at the top of the conductive and heat-conductive ring body, and a second film layer located at the bottom of the conductive and heat-conductive ring body; the first film layer, the conductive and heat-conductive ring body and the second film layer are arranged along the central axis of the conductive and heat-conductive ring body; the first film layer contacts the channel plate positioning piece, and the second film layer contacts the top wall of the reaction chamber body; the hardness of the conductive and heat-conductive ring body is greater than the hardness of the first film layer and the second film layer, and the hardness of the first film layer and the second film layer is less than the hardness of the channel plate positioning piece.

3. The plasma processing device according to claim 2, characterized in that: The material of the main body of the electrically conductive and thermally conductive ring is aluminum, and the materials of the first film layer and the second film layer are graphite.

4. The plasma processing device according to claim 1, characterized in that: The thickness of the electrically conductive and thermally conductive ring is 0.08 mm to 0.15 mm.

5. The plasma processing device according to claim 1, characterized in that: The resistivity of the conductive and thermally conductive ring is less than or equal to 1×10 -5 Ω*m; the thermal conductivity of the conductive and thermally conductive ring is greater than or equal to 100W / (m*K).

6. The plasma processing device according to claim 1, characterized in that: The electrical and thermal conductive ring is grounded.

7. The plasma processing device according to claim 1, characterized in that: Also includes: A cooling system, the cooling system comprising: a cooling source; A channel is located in the top wall of the reaction chamber body, and the channel is connected to the cold source through a pipeline.

8. The plasma processing device according to claim 1, characterized in that: The channel plate positioning member has a plurality of first positioning holes penetrating the channel plate positioning member; the conductive and thermally conductive ring has a plurality of second positioning holes penetrating the conductive and thermally conductive ring, and the first positioning holes and the second positioning holes are connected; The plasma processing device further includes a fastener, which fastens the channel plate positioning member and the conductive and thermally conductive ring to the top wall of the reaction chamber body, and the fastener is located in the first positioning hole and the second positioning hole.

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