Lower electrode assembly and plasma processing device

Abstract

A lower electrode assembly and a plasma processing device, wherein the lower electrode assembly comprises: a base, in which a groove is provided; an electrostatic chuck, located on the base, for adsorbing a substrate to be processed, in which a first gas channel is provided, the first gas channel corresponds to the groove; a first ceramic part and a second ceramic part, which are arranged in the groove, and the two cooperate with each other to form a second gas channel, the second gas channel is interconnected with the first gas channel, and is used to transport cooling gas to the back of the substrate to be processed to control the temperature of the substrate to be processed, wherein the second gas channel is non-linear. The lower electrode assembly is conducive to reducing the occurrence of ignition discharge of the electrostatic chuck.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and in particular to a lower electrode assembly and a plasma processing device. Background Art

[0002] Among the various processes in semiconductor device manufacturing, plasma processing is a key process for shaping the substrate to a desired design. In a typical plasma treatment process, process gases are excited by radio frequency (RF) to form a plasma. This plasma, after passing through the electric field (capacitive coupling or inductive coupling) between the upper and lower electrodes, physically bombards and chemically reacts with the surface of the substrate to be processed, thereby treating the substrate surface.

[0003] The plasma treatment process is performed within a plasma processing apparatus, which includes a susceptor and an electrostatic chuck located above the susceptor. The electrostatic chuck is used to hold the substrate to be processed. Typically, helium holes are provided within the susceptor and electrostatic chuck to deliver helium to the backside of the substrate to be processed, thereby controlling its temperature. However, existing helium holes are prone to ignition discharge issues. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a lower electrode assembly and a plasma processing device to reduce the occurrence of ignition discharge in an electrostatic chuck.

[0005] In order to solve the above technical problems, the present invention provides a lower electrode assembly, including: a base, which is provided with a groove; an electrostatic chuck, located on the base, for adsorbing the substrate to be processed, and provided with a first gas channel, the first gas channel corresponding to the groove; used to transport cooling gas to the surface of the substrate to be processed to control the temperature of the substrate to be processed; a first ceramic part and a second ceramic part, which are arranged in the groove, and the two cooperate with each other to form a second gas channel, the second gas channel is interconnected with the first gas channel, and is used to transport cooling gas to the back side of the substrate to be processed to control the temperature of the substrate to be processed, wherein the second gas channel is non-linear.

[0006] Optionally, the base is made of metal; and the electrostatic chuck is made of ceramic.

[0007] Optionally, the second gas channel is a bent structure or a curved structure.

[0008] Optionally, when the non-straight line of the second gas channel is a bent structure, a first opening is provided at the bottom of the first ceramic part and passes through a portion of the first ceramic part, and a second opening is provided on the side wall of the top of the first ceramic part; an opening is provided at the bottom of the second ceramic part, the opening is used to accommodate the top of the first ceramic part, and the second opening is surrounded by the opening, a gap is formed between the top of the first ceramic part and the inner side wall of the opening, a third opening is provided at the top of the second ceramic part, and the first opening, the second opening, the gap and the third opening are connected, the first opening, the second opening, the gap and the third opening constitute the second gas channel, and the center line of the gap is not collinear with the center line of the first opening and the third opening.

[0009] Optionally, the first ceramic part includes a bottom part and a boss part located above the bottom part, the projected area of ​​the boss part on the base is smaller than the projected area of ​​the bottom part on the base, the first opening passes through the bottom part and part of the boss part, the second opening is provided with a side wall of the boss part, the opening of the second ceramic part is used to accommodate the boss part, and the boss part and the side wall of the opening form the gap.

[0010] Optionally, the first ceramic piece and the second ceramic piece are placed left and right or up and down, and cooperate with each other to form a non-linear second gas channel.

[0011] Optionally, the first ceramic part includes a first side, the second ceramic part includes a second side, the first ceramic part on the first side is serrated, the second ceramic part on the second side is serrated, and the first side and the second side cooperate with each other to form the second gas channel.

[0012] Optionally, the outer wall of the first ceramic part is provided with a spiral groove, and the second ceramic part is a cylindrical structure. The second ceramic part is sleeved on the outside of the first ceramic part, and the second gas channel is formed between the spiral groove and the inner wall of the second ceramic part.

[0013] Optionally, the first ceramic part and the second ceramic part are integrally formed, and the second gas channel is provided in the first ceramic part and the second ceramic part. The second gas channel is formed by stacking a plurality of diamond channels, and each diamond channel further includes a connecting channel connecting diagonals.

[0014] Optionally, it also includes: a high-frequency power source electrically connected to the lower electrode.

[0015] Optionally, the power of the high-frequency power source is 3KW to 12KW.

[0016] Optionally, the materials of the first ceramic component and the second ceramic component include: aluminum oxide, aluminum nitride or zirconium oxide.

[0017] Optionally, the cooling gas includes at least one of an inert gas, N2 and O2.

[0018] Correspondingly, the present invention also provides a plasma processing device, comprising: a reaction chamber; and the above-mentioned lower electrode assembly, located at the bottom of the reaction chamber.

[0019] Optionally, the plasma processing device is an inductively coupled plasma processing device, and the inductively coupled plasma processing device further includes: an insulating window located at the top of the reaction chamber; and an inductive coil located above the insulating window.

[0020] Optionally, the plasma processing device is a capacitively coupled plasma processing device, which includes: a mounting substrate located at the top of the reaction chamber; a gas shower head located below the mounting substrate and arranged opposite to the lower electrode assembly, for transporting reaction gas into the reaction chamber.

[0021] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0022] In the plasma processing device provided by the technical solution of the present invention, the plasma processing device includes a lower electrode assembly, a groove is provided in the base of the lower electrode assembly, the groove is used to accommodate a first ceramic part and a second ceramic part, the first ceramic part and the second ceramic part cooperate with each other to form a second gas channel, a first gas channel is provided in the electrostatic chuck, the first gas channel and the second gas channel are interconnected to form a transmission path for delivering cooling gas to the back side of the substrate to be processed, wherein the second gas channel is non-linear, so that the cooling gas turns during the transmission process and is extinguished at the turning point, thereby helping to reduce the problem of ignition discharge in the electrostatic chuck. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic structural diagram of a plasma processing device according to the present invention;

[0024] Figure 2 It is a structural schematic diagram of another plasma processing device of the present invention;

[0025] Figure 3 for Figure 1 An enlarged schematic diagram of the middle region A;

[0026] Figure 4 for Figure 3 A three-dimensional image of a first ceramic member;

[0027] Figure 5a and Figure 5b for Figure 3A three-dimensional image of a second ceramic member;

[0028] Figure 6 for Figure 1 Another enlarged schematic diagram of the middle area A;

[0029] Figure 7 for Figure 1 Another enlarged schematic diagram of the middle area A;

[0030] Figure 8 for Figure 1 Another enlarged schematic diagram of the middle area A;

[0031] Figure 9 for Figure 8 A top view of the first ceramic component and the second ceramic component. DETAILED DESCRIPTION

[0032] As described in the background art, ignition discharge is prone to occur in the electrostatic chuck of existing plasma processing devices. Therefore, the present invention is dedicated to providing a plasma processing device to reduce the occurrence of ignition discharge in the electrostatic chuck. The following is a detailed description:

[0033] Figure 1 This is a schematic structural diagram of a plasma processing device according to the present invention.

[0034] Please refer to Figure 1 The plasma processing device 1 includes: a reaction chamber 10; a lower electrode assembly located at the bottom of the reaction chamber 10, the lower electrode assembly including a base 12 and an electrostatic chuck 13 above the base 12, and an electrode 14 is provided in the electrostatic chuck 13 for adsorbing the substrate W to be processed.

[0035] In this embodiment, the plasma processing apparatus is a capacitively coupled plasma processing apparatus, further comprising: a mounting substrate 15 located at the top of the reaction chamber 10; and a gas showerhead 16 located below the mounting substrate 15, connected to a reaction gas source 17, for delivering reaction gas into the reaction chamber 10, and disposed opposite the lower electrode assembly. The gas showerhead 16 serves as the upper electrode of the plasma processing apparatus, and the electrostatic chuck 13 serves as the lower electrode of the plasma processing apparatus, with a reaction region formed between the upper and lower electrodes. At least one radio frequency power source 19 is applied to either the upper or lower electrode via a matching network 18, generating a radio frequency electric field between the upper and lower electrodes to dissociate the reaction gas into a plasma. The plasma contains a large number of active species, such as electrons, ions, excited atoms, molecules, and free radicals. These active species can undergo various physical and chemical reactions with the surface of the substrate W to be processed, thereby changing the substrate surface morphology and completing the etching process. An exhaust pump 20 is further provided below the reaction chamber 10 for discharging reaction by-products from the reaction chamber to maintain a vacuum environment in the reaction chamber.

[0036] The RF power source 19 is a high-frequency power source with a power range of 3 kW to 12 kW. The base 12 is made of metal, while the electrostatic chuck 13 is made of ceramic. The electrostatic chuck 13 is used to electrostatically attach the substrate W to be processed. When the high-frequency power source is applied to the base 12, a voltage difference is generated across the electrostatic chuck 13.

[0037] During the process of processing the surface of the substrate W to be processed, it is necessary to precisely control the temperature of the substrate W to be processed. A cooling channel is usually provided in the base 12, and the cooling channel is used to transport a coolant, and the coolant is used to cool the base 12. An insulating layer (not shown in the figure) is also provided between the electrostatic chuck 13 and the base 12, and a heater (not shown in the figure) is provided in the insulating layer, and the heater is used to heat the substrate to be processed. In addition, in order to better control the temperature of the substrate W to be processed, a gas channel 21 is usually provided in the base 12 and the electrostatic chuck 13. The gas channel 21 is used to transport a cooling gas to the back side of the substrate W to be processed. The cooling gas includes: at least one of an inert gas, N2 and O2, and the inert gas includes helium. Due to the voltage difference between the electrostatic chuck 13, ignition discharge is prone to occur during the transmission of the cooling gas in the gas channel 21.

[0038] Figure 2 Schematic diagram of the structure of another plasma processing device of the present invention.

[0039] In this embodiment, the plasma processing apparatus is an inductively coupled plasma processing apparatus. The inductively coupled plasma processing apparatus 5 includes a reaction chamber 501. The reaction chamber 501 includes a generally cylindrical reaction chamber sidewall made of metal. An opening 502 is provided in the reaction chamber sidewall for accommodating the entry and exit of substrates. An insulating window 517 is provided above the reaction chamber sidewall. An inductively coupled coil 515 is disposed above the insulating window 517. An RF power source 518 applies an RF voltage to the inductively coupled coil 515 via an RF matching network 516.

[0040] A liner 520 is provided within the reaction chamber to protect the inner wall of the reaction chamber from plasma corrosion. A gas injection port 503 is provided on one end of the reaction chamber sidewall near the insulating window. In other embodiments, a gas injection port can also be provided in the central area of ​​the insulating window 517. The gas injection port 503 is used to inject the reaction gas into the reaction chamber 501. The radio frequency power of the radio frequency power source 518 drives the inductive coupling coil 515 to generate a strong high-frequency alternating magnetic field, which ionizes the low-pressure reaction gas in the reaction chamber to generate plasma. A base 510 is provided downstream of the reaction chamber 500. An electrostatic chuck 512 is provided on the base 510. An electrostatic electrode 513 is provided within the electrostatic chuck 512 to generate electrostatic attraction to support and fix the substrate W to be processed during the process. The plasma contains a large number of active species such as electrons, ions, excited atoms, molecules, and free radicals. These active species can undergo various physical and chemical reactions with the surface of the substrate to be processed, causing the morphology of the substrate surface to change, thus completing the etching process. A bias RF power source 550 applies a bias RF voltage to the susceptor via an RF matching network 552 to control the impact direction of charged particles in the plasma. An exhaust pump 540 is also located below the reaction chamber 501 to remove reaction byproducts from the chamber and maintain a vacuum environment.

[0041] Similarly, to better control the temperature of the substrate W being processed, a gas channel 51 is typically provided within the pedestal 510 and electrostatic chuck 512. The gas channel 51 is used to deliver cooling gas, which includes at least one of an inert gas, N2, and O2, to the backside of the substrate W being processed. The inert gas may include helium. Due to the voltage difference across the electrostatic chuck 512, ignition discharges are easily generated during the cooling gas's transport within the gas channel 51.

[0042] The following is a detailed description of the lower electrode assembly:

[0043] Please refer to Figure 3 To Figure 5, Figure 3 for Figure 1 An enlarged schematic diagram of the middle region A, the lower electrode assembly includes: a base 12, which has a groove 120 (see Figure 2 ); an electrostatic chuck 13 is located on the base 12 and is used to adsorb the substrate W to be processed, and a first gas channel 131 is provided therein, and the first gas channel 131 corresponds to the groove 120; a first ceramic part 121 and a second ceramic part 122 are provided in the groove 120, and the two cooperate with each other to form a second gas channel, and the second gas channel is interconnected with the first gas channel 131, and is used to transport cooling gas to the back side of the substrate W to be processed to control the temperature of the substrate W to be processed, wherein the second gas channel is non-linear.

[0044] The materials of the first ceramic member 121 and the second ceramic member 122 include aluminum oxide, aluminum nitride, or zirconium oxide.

[0045] The significance of setting the first ceramic part 121 and the second ceramic part 122 is that: since the first ceramic part 121 and the second ceramic part 122 are both made of ceramic materials, the distance between the substrate W to be processed and the base 12 needs to span the electrostatic chuck 13, the first ceramic part 121 and the second ceramic part 122. Therefore, the distance between the substrate W to be processed and the base 12 is relatively far, which is beneficial to prevent arc discharge (arcing) from occurring in the first gas duct 131.

[0046] Figure 4 is a three-dimensional diagram of the first ceramic member 121, combined with Figure 3 and Figure 4 It can be seen that in this embodiment, the first ceramic part 121 includes: a bottom part 121a and a boss part 121b located above the bottom part 121a, the projected area of ​​the boss part 121b on the base 12 is smaller than the projected area of ​​the bottom part 121a on the base 12, the first ceramic part 121 is provided with a first opening 123 that passes through the bottom part 121a and part of the boss part 121b, and the side wall of the boss part 121b is provided with a second opening 124.

[0047] In other embodiments, a first opening is provided at the bottom of the first ceramic piece and penetrates part of the first ceramic piece, and a second opening is provided on the side wall of the top of the first ceramic piece; an opening is provided at the bottom of the second ceramic piece, and the opening is used to accommodate the top of the first ceramic piece, and the second opening is surrounded by the opening, and a gap is formed between the top of the first ceramic piece and the inner side wall of the opening, a third opening is provided at the top of the second ceramic piece, and the first opening, the second opening, the gap and the third opening are connected, and the first opening, the second opening, the gap and the third opening constitute the second gas channel.

[0048] Figure 5a and Figure 5b for Figure 2 A three-dimensional image of a second ceramic part.

[0049] Please refer to Figure 3 、 Figure 4 、 Figure 5a and Figure 5b , an opening 127 is provided at the bottom of the second ceramic part 122, and the opening 127 is used to accommodate the boss part 121b, and a gap 125 is formed between the boss part 121b and the inner wall of the opening 127, and a third opening 126 is provided at the top of the second ceramic part 122, and the first opening 123, the second opening 124, the gap 125 and the third opening 126 are connected, the first opening 123, the second opening 124, the gap 125 and the third opening 126 constitute a second gas channel, and the second gas channel is connected to the first gas channel 131, then the first opening 123, the second opening 124, the gap 125, the third opening 126 and the first gas channel 141 form the transmission path of the cooling gas, and the center line of the gap is not collinear with the center line of the first opening and the third opening.

[0050] Since the first opening 123 passes through the bottom part 121a and part of the boss part 121b, and the second opening 124 is provided on the side wall of the boss part 121b, the first opening 123 and the second opening 124 form an angle, and the gap 125 includes: a first gap between the side wall of the boss part 121b and the inner side wall of the opening 127 of the second ceramic part 122, and a second gap between the top of the boss part 121b and the bottom of the opening 127 of the second ceramic part 122, the first gap and the second gap form an angle, and the boss part 121b is provided on the side wall of the boss part 121b. The first gap between the side wall of the component 121b and the inner side wall of the opening 127 of the second ceramic component 122 forms an angle with the second opening 124, and the third opening 126 is arranged in the second ceramic component 122 at the bottom of the opening 127. Therefore, an angle is formed between the second gap and the third opening 126. It can be seen that the second gas channel is a multi-bending structure, so that the cooling gas continuously turns during the transmission process in the second gas channel, so that its energy is continuously reduced. Therefore, although there is a voltage difference between the upper and lower surfaces of the electrostatic chuck 13, ignition discharge is not easy to occur.

[0051] The transmission path of the cooling gas is non-linear transmission. In addition to the above-mentioned bending structure, the non-linear transmission can also be curved transmission.

[0052] Figure 6 for Figure 1 Another enlarged schematic diagram of area A in the middle.

[0053] In this embodiment, the electrostatic chuck 23 is arranged in the first gas channel 231, and the base 22 is arranged in the groove, and the groove is arranged in the first ceramic part 221 and the second ceramic part 222. The first ceramic part 221 includes a first side 1, and the second ceramic part 222 includes a second side 2. The first side 1 and the second side 2 are placed to match each other on the left and right, and a second gas channel 223 is formed between the first ceramic part 221 and the second ceramic part 222.

[0054] In this embodiment, the first side 1 is serrated, and the second side 2 is serrated, and the two cooperate to form a second gas channel 223. Since the second gas channel 223 is non-straight, the cooling gas turns during the transmission between the first gas channel 231 and the second gas channel 223, and is extinguished at the turning point. Therefore, it is helpful to reduce the problem of ignition discharge between the substrate to be processed and the electrostatic chuck 23.

[0055] Figure 7 for Figure 1 Another enlarged schematic diagram of area A in the middle.

[0056] Please refer to Figure 7 The first ceramic part and the second ceramic part are integrally formed into a ceramic part 34. The second gas channel 341 is provided in the ceramic part 34. The second gas channel 341 includes a plurality of diamond channels stacked together, and each diamond channel also includes a connecting channel 342 connecting the diagonals.

[0057] In this embodiment, since the second gas channel 341 is non-straight, the cooling gas turns during transmission between the first gas channel 331 and the second gas channel 341 and is extinguished at the turning point. This is beneficial to reducing the problem of ignition discharge between the substrate to be processed and the electrostatic chuck 33.

[0058] Figure 8 for Figure 1 Another enlarged schematic diagram of the middle area A; Figure 9 for Figure 8 A top view of the first ceramic component and the second ceramic component.

[0059] Please refer to Figure 8 and Figure 9 The outer wall of the first ceramic part 421 is provided with a spiral groove 423, and the second ceramic part 422 is a cylindrical structure. The second ceramic part 422 is sleeved on the outside of the first ceramic part 421, and the second gas channel is formed between the spiral groove 423 and the inner wall of the second ceramic part 422.

[0060] In this embodiment, since the spiral groove 423 is non-linear, the second gas channel formed between the spiral groove 423 and the inner wall of the second ceramic part 422 is non-linear, so that the cooling gas turns during the transmission process between the first gas channel 431 and the second gas channel, and is extinguished at the turning point. Therefore, it is helpful to reduce the problem of ignition discharge between the substrate to be processed and the electrostatic chuck 43.

[0061] Although the present invention is disclosed 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 scope of protection of the present invention shall be based on the scope defined by the claims.

Claims

1. A lower electrode assembly, characterized in that: include: A base having a groove therein; An electrostatic chuck, located on the base, used for adsorbing the substrate to be processed, and having a first gas channel therein, the first gas channel corresponding to the groove; The first ceramic part and the second ceramic part are arranged in the groove, and the two are placed left and right or up and down, and the two cooperate with each other to form a second gas channel, and the second gas channel is interconnected with the first gas channel, and is used to transport cooling gas to the back side of the substrate to be processed to control the temperature of the substrate to be processed, wherein the second gas channel is a bent structure or a curved structure; the first ceramic part is in contact with the groove, and the second ceramic part is in contact with the groove.

2. The lower electrode assembly according to claim 1, characterized in that The base is made of metal; the electrostatic chuck is made of ceramic.

3. The lower electrode assembly according to claim 1, characterized in that When the first ceramic part and the second ceramic part are placed up and down, the first ceramic part is provided with a first opening at the bottom which penetrates part of the first ceramic part, and the side wall of the top of the first ceramic part is provided with a second opening; the second ceramic part is provided with an opening at the bottom, the opening is used to accommodate the top of the first ceramic part, and the second opening is surrounded by the opening, a gap is formed between the top of the first ceramic part and the inner side wall of the opening, a third opening is provided at the top of the second ceramic part, and the first opening, the second opening, the gap and the third opening are connected, the first opening, the second opening, the gap and the third opening constitute the second gas channel, and the center line of the gap is not colinear with the center line of the first opening and the third opening.

4. The lower electrode assembly according to claim 3, characterized in that: The first ceramic part includes a bottom part and a boss part located above the bottom part, the projection area of ​​the boss part on the base is smaller than the projection area of ​​the bottom part on the base, the first opening passes through the bottom part and part of the boss part, the second opening is provided with a side wall of the boss part, the opening of the second ceramic part is used to accommodate the boss part, and the boss part and the side wall of the opening form the gap.

5. The lower electrode assembly according to claim 1, characterized in that: When the first ceramic piece and the second ceramic piece are placed left and right, the first ceramic piece includes a first side, the second ceramic piece includes a second side, the first ceramic piece on the first side is serrated, the second ceramic piece on the second side is serrated, and the first side and the second side cooperate with each other to form the second gas channel.

6. The lower electrode assembly according to claim 1, characterized in that The first ceramic piece and the second ceramic piece are integrally formed, and the second gas channel is provided in the first ceramic piece and the second ceramic piece. The second gas channel is formed by stacking a plurality of rhombus channels, and each rhombus channel further includes a connecting channel connecting diagonals.

7. The lower electrode assembly according to claim 1, characterized in that: Also includes: A high frequency power source is electrically connected to the lower electrode.

8. The lower electrode assembly according to claim 7, characterized in that The power of the high frequency power source is 3KW~12KW.

9. The lower electrode assembly according to claim 1, characterized in that: The materials of the first ceramic component and the second ceramic component include: aluminum oxide, aluminum nitride or zirconium oxide.

10. The lower electrode assembly according to claim 1, wherein: The cooling gas includes at least one of an inert gas, N2 and O2.

11. A plasma processing device, characterized in that: include: Reaction chamber; The lower electrode assembly according to any one of claims 1 to 10 is located at the bottom of the reaction chamber.

12. The plasma processing apparatus according to claim 11, wherein: The plasma processing device is an inductively coupled plasma processing device, and the inductively coupled plasma processing device further comprises: an insulating window located at the top of the reaction chamber; and an inductive coil located above the insulating window.

13. The plasma processing apparatus according to claim 11, wherein: The plasma processing device is a capacitively coupled plasma processing device, which includes: a mounting substrate located at the top of the reaction chamber; a gas shower head located below the mounting substrate and arranged opposite to the lower electrode assembly for conveying reaction gas into the reaction chamber.

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