Plasma processing equipment, upper electrode assembly and its assembly method

Abstract

This invention proposes an upper electrode assembly disposed at the top of the reaction chamber of a plasma processing device, comprising: a mounting substrate and a gas spray head, the mounting substrate and the gas spray head being connected and fixed by a fastening device; and a thermoelectric connection assembly disposed between the mounting substrate and the gas spray head, the thermoelectric connection assembly comprising a raised ring and a covering film, the covering film being disposed on the top surface of the gas spray head, the raised ring being disposed circumferentially along the mounting substrate, the raised ring comprising a first end and a second end opposite to each other, the first end being fixed to the bottom surface of the mounting substrate, the second end being embedded in the covering film, and the second end always maintaining contact with the covering film, for dividing the upper electrode assembly into at least two ventilation areas; this invention saves material consumption, and through the always-contacting raised ring and covering film, it stably achieves thermoelectric conduction between the mounting substrate and the gas spray head, as well as mutual isolation between the ventilation areas.

Description

Technical Field

[0001] This invention relates to the field of semiconductor equipment, and more specifically to a plasma processing device, an upper electrode assembly, and an assembly method thereof. Background Technology

[0002] Vacuum processing equipment is widely used in the semiconductor industry, and plasma processing equipment is a commonly used type of vacuum processing equipment. The working principle of plasma processing equipment is to generate plasma by means of radio frequency coupled discharge, and then use the plasma to perform processing processes such as deposition and etching.

[0003] Among them, capacitively coupled plasma (CCP) etching equipment with upper and lower electrodes is one of the main plasma processors. The lower electrode is generally an electrostatic chuck above the base, and the upper electrode assembly generally includes a mounting substrate and a gas spray head disposed below the mounting substrate. The mounting substrate and the gas spray head are connected by bolts. Multiple gas channels run from top to bottom through the mounting substrate and the gas spray head. The gas channels are used to deliver process gas into the reaction chamber. Under the action of the upper and lower electrodes, the process gas dissociates into plasma, which reacts with the surface of the substrate, changing the morphology of the substrate surface, thereby completing the etching process.

[0004] Currently, in order to regulate the gas in different areas of the substrate surface separately, a rubber ring is placed between the mounting substrate and the gas spray head to divide the lower electrode assembly into at least two concentric ventilation areas, thereby achieving independent gas control between different areas. In order to achieve stable control of the gas spray head temperature and the entire RF circuit, a special thermally conductive pad (shim) is placed between the mounting substrate and the gas spray head to achieve heat and electricity conduction. This method of separating the rubber ring and thermal pad allows the mounting substrate and gas spray head to fit tightly during the assembly of plasma equipment at room temperature. However, during the use of the plasma equipment, due to the difference in the coefficients of thermal expansion between the mounting substrate and the gas spray head (the mounting substrate is generally metal, while the gas spray head is silicon or silicon carbide), a gap will form between them at high process temperatures. The plasma below the gas spray head diffuses into this gap and then comes into contact with the rubber ring and thermal pad. With prolonged and repeated use of the CCP etching equipment, the rubber ring and thermal pad will gradually be corroded by the plasma. This not only increases material consumption, but the corrosion of the rubber ring and thermal pad also affects the contact between the mounting substrate and the gas spray head, affecting the thermal and electrical conductivity between them, and thus affecting the processing effect of the plasma below the gas spray head on the substrate.

[0005] In summary, a new upper electrode assembly needs to be developed for plasma processing equipment, which can stably achieve gas isolation between different regions of the upper electrode assembly at different temperatures, and also achieve stable thermoelectric conduction between the mounting substrate and the gas spray head. Summary of the Invention

[0006] The purpose of this invention is to provide a plasma processing device, an upper electrode assembly, and an assembly method thereof, in order to solve the problem that when the current upper electrode assembly separates different gas regions, a significant gap is generated between the mounting substrate and the gas spray head. When plasma enters this gap, it consumes the thermoelectric connection components, thereby affecting the contact between the mounting substrate and the gas spray head and resulting in poor thermal and electrical conductivity between them.

[0007] To achieve the above objectives, the present invention proposes an upper electrode assembly disposed at the top of the reaction chamber of a plasma processing device, comprising: a mounting substrate and a gas spray head, the mounting substrate and the gas spray head being connected and fixed by a fastening device; and a thermoelectric connection assembly disposed between the mounting substrate and the gas spray head, the thermoelectric connection assembly comprising a metal protruding ring and a covering film, the covering film being disposed on the top surface of the gas spray head, the protruding ring being disposed circumferentially along the mounting substrate, the protruding ring comprising a first end and a second end opposite to each other, the first end being fixed to the bottom surface of the mounting substrate, the second end being embedded in the covering film, and the second end always maintaining contact with the covering film, for dividing the upper electrode assembly into at least two ventilation areas.

[0008] Optionally, the longitudinal section of the protruding ring is tapered, with the area of ​​its first end being larger than the area of ​​its second end.

[0009] Optionally, after the second end of the protruding ring is embedded in the covering film, the covering film is present between the second end of the protruding ring and the top surface of the gas spray head.

[0010] Optionally, the covering film uniformly covers the top surface of the gas spray head, and the thickness of the covering film is greater than 100 μm.

[0011] Optionally, the cover film and the mounting substrate are made of the same material.

[0012] Optionally, the hardness of the raised ring is not less than the hardness of the covering film.

[0013] Optionally, both the raised ring and the cover film are made of aluminum, the raised ring is integrally formed with the mounting substrate, and the cover film is applied to the top surface of the gas spray head by thermal evaporation or vapor deposition.

[0014] Optionally, the bottom surface of the mounting substrate is composed of a first part and a second part. The first part is provided with the protruding ring, and the second part, which is located at the position where a gap is generated between the bottom surface of the mounting substrate and the cover film at the process temperature, is covered with an anodized coating.

[0015] Optionally, the upper electrode assembly is provided with multiple gas channels distributed in a dispersed manner, each gas channel passing through the mounting substrate and the gas spray head, and the gas channel is used to input process gas into the reaction chamber.

[0016] Optionally, the raised rings can be configured as N, and the raised rings are concentrically arranged with the mounting substrate. These raised rings divide the upper electrode assembly into N+1 concentric ventilation areas, and the gas channels are distributed in the ventilation areas.

[0017] Optionally, the area of ​​the first end of the outer ring's raised ring is larger than the area of ​​the first end of the inner ring's raised ring.

[0018] Optionally, each of the protruding rings includes at least two concentric protruding sub-rings.

[0019] A second aspect of the present invention provides a plasma processing device, comprising: a reaction chamber having a base for placing a substrate to be processed within the reaction chamber, and the aforementioned upper electrode assembly disposed opposite to the base and located at the top of the reaction chamber; a radio frequency power supply connected to the base, and a reaction gas supply channel connected to the gas channel of the upper electrode assembly; wherein a raised ring divides the upper electrode assembly into multiple ventilation zones to achieve independent gas control in different ventilation zones.

[0020] A third aspect of the present invention provides a method for assembling an upper electrode assembly, comprising the following steps: A covering film is placed on the top surface of the gas spray head, and a raised ring is provided circumferentially on the bottom surface of the mounting substrate. The protruding ring is pressed and embedded into the cover film, thereby separating the mounting base and the gas spray head into multiple ventilation areas; The gas spray head and the mounting base are connected and fixed by a fastening device to form the upper electrode assembly; The gas spray head and the mounting base plate are provided with multiple through gas channels, and the corresponding gas channels are aligned when connecting the gas spray head and the mounting base plate.

[0021] Optionally, the covering film can be uniformly covered on the top surface of the gas spray head by thermal evaporation or vapor deposition.

[0022] Optionally, after the raised ring is provided on the bottom surface of the mounting substrate and before the raised ring is embedded in the cover film, an anodized coating is applied to the second portion corresponding to the part of the mounting substrate exposed in the reaction chamber and the location where a gap is generated between the bottom surface of the mounting substrate and the cover film at the process temperature.

[0023] Optionally, a plurality of concentric raised rings are provided on the bottom surface of the mounting substrate.

[0024] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects: In the upper electrode assembly proposed in this invention, a thermoelectric connection assembly is provided between the mounting substrate and the gas spray head. This thermoelectric connection assembly includes a raised ring and a covering film. The covering film is disposed on the top surface of the gas spray head, and the raised ring is arranged circumferentially along the mounting substrate. The second end of the raised ring is embedded in the covering film, and the two are controlled to maintain contact at room temperature and process temperature, thereby separating the ventilation areas. Furthermore, the consistently contacting raised ring and covering film stably achieve thermoelectric conduction between the mounting substrate and the gas spray head, as well as mutual isolation between the ventilation areas. This solution uses a metal thermoelectric connection assembly instead of an organic one, avoiding the consumption of organic thermoelectric connection assemblies by plasma. This solution further enhances the heat conduction between the mounting substrate and the gas spray head by using a cover film made of the same material as the mounting substrate. The cover film has the same coefficient of thermal expansion and thermal conductivity as the mounting substrate, so that heat is conducted from the gas spray head to the mounting substrate more quickly. As a result, the deformation of the gas spray head and the mounting substrate is small, and the gap formed between them is also small. As a result, less plasma enters the gap, further reducing the consumption of plasma on the thermoelectric connection components. This solution expands the heat conduction area between the gas spray head and the mounting substrate by setting a raised ring including at least two raised sub-rings, further accelerating the heat conduction rate between the two, reducing the impact of heat accumulation on the deformation of the gas spray head and the mounting substrate, reducing the gap between the two, and further ensuring the contact between the raised ring and the cover film, thereby better isolating different ventilation areas. This design sets the first end area of ​​the outer ring's raised ring to be larger than the first end area of ​​the inner ring's raised ring, thereby accelerating the heat conduction speed of the outer ring of the upper electrode assembly, reducing the accumulation of heat on the outer ring of the gas spray head, thus reducing the deformation of the outer ring of the gas spray head and the mounting substrate, making it less likely for a significant gap to form between their outer rings, and reducing the amount of plasma entering the gap. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a capacitively coupled plasma (CCP) processing device. Figure 2 This is a schematic diagram of the reaction chamber and upper electrode assembly according to an embodiment of the present invention; Figure 3 This is a partial structural schematic diagram of a thermoelectric connection assembly according to an embodiment of the present invention; Figure 4 This is a partial structural schematic diagram of the upper electrode assembly according to an embodiment of the present invention; Figure 5 This is a bottom view of the mounting substrate according to an embodiment of the present invention. Detailed Implementation

[0026] The technical solutions, structural features, achieved objectives, and effects of the present invention will be described in detail below with reference to the accompanying drawings in the embodiments of the present invention.

[0027] It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions. They are only used to facilitate and clarify the purpose of illustrating the embodiments of the present invention, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationship, or adjustments to the size should still fall within the scope of the technical content disclosed in the present invention, provided that they do not affect the effects and objectives that the present invention can produce.

[0028] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only the expressly listed elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0029] Current capacitively coupled plasma (CCP) processing equipment, such as Figure 1 As shown, the system includes a reaction chamber 100, which contains a gas spray head 150 and a base 180 disposed opposite to the gas spray head 150. A reaction area is formed between the gas spray head 150 and the base 180. The gas spray head 150 is connected and fixed to a mounting plate 120 above it. The gas spray head 150 and the mounting plate 120 together serve as the upper electrode assembly of the reaction chamber. Multiple gas channels 130 pass through the upper electrode assembly from top to bottom.

[0030] To achieve independent gas control in different areas of the reaction zone, the upper electrode assembly is divided into multiple ventilation zones by multiple thermoelectric connection components 140. Each thermoelectric connection component 140 generally includes: multiple concentric annular grooves 141 formed on the lower surface of the mounting substrate 120; an annular rubber ring 142 disposed within each annular groove 141 and matching the groove; and a thermally conductive pad 143 disposed between the lower surface of the mounting substrate 120 and the upper surface of the gas spray head 150, with the thermally conductive pad 143 and the rubber ring 142 horizontally offset. By distributing multiple annular grooves 141 and rubber rings 142 between the mounting substrate 120 and the gas spray head 150, the upper electrode assembly is divided into multiple concentric ventilation zones. Multiple gas channels 130 are distributed within these ventilation zones, and the gas channels 130 in different ventilation zones are not interconnected. Thermoelectric conduction between the mounting substrate 120 and the gas spray head 150 is achieved through the thermally conductive pad 143.

[0031] When assembling the plasma processing equipment at room temperature, the lower surface of the mounting substrate 120 can be controlled to be in close contact with the upper surface of the gas spray head 150. However, during the process, when the temperature of the reaction chamber 100 rises to the process temperature, the plasma below the gas spray head 150 comes into contact with the gas spray head 150. The high-temperature plasma conducts heat into the gas spray head 150. Due to the contact between the mounting substrate 120 and the gas spray head 150 and the presence of the thermoelectric connection assembly 140, heat is conducted from the gas spray head 150 back to the mounting substrate 120. The mounting substrate 120 is provided with cooling pipes, thereby reducing the heat conducted to the mounting substrate. The heat is carried away by the substrate 120. During the above process, both the mounting substrate 120 and the gas spray head 150 are heated. However, because the mounting substrate 120 and the gas spray head 150 are made of different materials—the mounting substrate 120 is generally made of metal, such as aluminum, while the gas spray head 150 is generally made of silicon or silicon carbide—their thermal conductivity and coefficient of thermal expansion are different (aluminum has a higher thermal conductivity and coefficient of thermal expansion than silicon or silicon carbide). Therefore, the thermal expansion of the mounting substrate 120 is greater than that of the gas spray head 150, resulting in an unevenly distributed gap between the mounting substrate 120 and the gas spray head 150. At this time, heat is carried away from the gas spray head. When heat is transferred from the gas nozzle 150 to the mounting substrate 120, it relies more heavily on the thermoelectric connection assembly 140. However, since the thermoelectric connection assembly 140 mainly consists of an organic rubber ring 142 and a thermally conductive pad 143, its heat conduction rate is significantly reduced. This causes heat to accumulate within the gas nozzle 150. This accumulated heat also affects the lower part of the mounting substrate 120, increasing the deformation of both the gas nozzle 150 and the lower part of the mounting substrate 120. Consequently, the gap between the mounting substrate 120 and the gas nozzle 150 widens, allowing plasma from the reaction area to diffuse into this gap and come into contact with the thermally conductive material. The gasket 143 and rubber ring 142 are corroded by active groups formed by the dissociation of gases such as C4F8 and O2 in the plasma. These active groups corrode the organic materials of the rubber ring 142 and the thermally conductive gasket 143. With prolonged and repeated use of the plasma processing equipment, the thermally conductive gasket 143 and rubber ring 142 are gradually corroded by the active groups in the plasma, leading to the wear and tear of the materials (thermally conductive gasket 143 and rubber ring 142) of the thermoelectric connection component 140. As the corrosion of the thermally conductive gasket 143 and rubber ring 142 becomes more severe, it will also affect the contact and thermoelectric conduction between the mounting substrate 120 and the gas spray head 150. When the rubber ring 142 is corroded more severely, it will also affect the isolation of the gas channels 130 between different ventilation areas, thus making it impossible to independently control the gas in different areas.

[0032] To address the aforementioned issues, this invention discloses an upper electrode assembly. By providing a concentric metal protrusion ring on the bottom surface of a mounting substrate and a metal covering film on the top surface of a gas spray head, the protrusion ring embeds into the covering film when the mounting substrate and gas spray head are pressed and fixed together. During the process, the protrusion ring remains in contact with the covering film to form a seal, dividing the upper electrode assembly into at least two ventilation zones. Since this invention eliminates the need for organic rubber rings and thermally conductive pads as thermoelectric connection components to separate different ventilation zones between the mounting substrate and the gas spray head, the thermoelectric connection components of this invention do not suffer from the defect of being easily corroded by active groups formed by the dissociation of gases such as C4F8 and O2 in plasma, thus reducing material loss. Furthermore, this upper electrode assembly can stably achieve gas isolation between different ventilation zones at different temperatures (especially process temperatures), providing a basis for independent gas control in different ventilation zones. Additionally, the metal thermoelectric connection components achieve stable thermoelectric conduction between the mounting substrate and the gas spray head.

[0033] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0034] like Figure 2 As shown, the reaction chamber 200 of a plasma device in this embodiment includes a generally cylindrical reaction chamber sidewall 160. The reaction chamber 200 includes an upper electrode assembly and a base 180 disposed opposite to the upper electrode assembly. An electrostatic chuck is provided above the base 180 for carrying the substrate 170 to be processed. The electrostatic chuck also serves as a lower electrode. The reaction area is between the upper electrode assembly and the lower electrode. Multiple gas channels 230 run from top to bottom through the upper electrode assembly. Each gas channel 230 connects a gas buffer 110 to the reaction area below a gas spray head 150. The gas buffer 110 is also connected to a process gas source through an external reaction gas supply channel, thereby spraying process gas into the reaction area through the gas channels 230. Low-frequency and high-frequency power are applied to one of the upper electrode assembly or the lower electrode through a matching network 190 to generate a radio frequency electric field in the reaction area, dissociating the process gas into plasma, and causing an etching reaction on the surface of the substrate 170.

[0035] The upper electrode assembly includes: a mounting substrate 220, a disc-shaped gas spray head 250 connected below the mounting substrate 220, and a thermoelectric connection assembly 240 disposed between the mounting substrate 220 and the gas spray head 250; the thermoelectric connection assembly 240 includes: a cover film 242 disposed on the top surface of the gas spray head 250, and an annular protrusion ring 241 disposed circumferentially along the mounting substrate 220, the protrusion ring 241 being concentric with the mounting substrate 220; Figure 3As shown, the protruding ring 241 includes a first end 2411 and a second end 2412 opposite to each other. The first end 2411 is fixed to the bottom surface of the mounting substrate 220, and the second end 2412 is pressed and embedded in the cover film 242. The second end 2412 always keeps in contact with the cover film 242, thereby dividing the upper electrode assembly into at least two ventilation areas. Multiple gas channels 230 are distributed in these ventilation areas, and the gas channels 230 in different ventilation areas are not interconnected.

[0036] like Figure 3 and Figure 4 As shown, for the assembled reaction chamber 200, after the second end 2412 is embedded in the covering film 242, the top surface of the covering film 242 is in contact with the bottom surface of the mounting substrate 220, and the second end 2412 of the protruding ring 241 has the covering film 242 between it and the top surface of the gas spray head 250. That is, the second end 2412 is in contact with the covering film 242 to isolate the ventilation area, and the second end 2412 is not in contact with the gas spray head 250. The mounting substrate 220 and the gas spray head 250 can conduct heat and electricity through the protruding ring 241 and the covering film 242 between them.

[0037] As attached Figures 2 to 4 As shown, the longitudinal section of the protruding ring 241 is conical, and the area of ​​its first end 2411 is larger than the area of ​​its second end 2412. Therefore, when assembling the upper electrode assembly, the covering film 242 at the second end 2412 experiences greater pressure, and the second end 2412 is more easily pressed into the covering film 242, thereby dividing the upper electrode assembly into at least two ventilation areas. Figure 4 (A, B, C, D in the diagram). Furthermore, to make the second end 2412 easier to embed into the cover film 242, the hardness of the protruding ring 241 is set to be no less than the hardness of the cover film 242.

[0038] At the process temperature, the high-temperature plasma below the gas spray head 250 contacts the gas spray head 250, conducting heat into the gas spray head 250. Due to the contact between the mounting substrate 220 and the gas spray head 250, and the presence of the thermoelectric connection assembly 240, heat is conducted from the gas spray head 250 to the mounting substrate 220. The mounting substrate 220 is provided with cooling pipes to remove the heat conducted to it. During this process, because the top surface of the gas spray head 250 is covered with a metal cover film 242, the heat conduction rate between the metal cover film 242 and the metal mounting substrate 220 is faster than the direct heat conduction rate between the metal mounting substrate and the silicon-based gas spray head in the prior art. Furthermore, the cover film 242 and the protruding ring 241 in the thermoelectric connection assembly 240 of this invention are also metal, and the heat conduction rate of the thermoelectric connection assembly 240 is also greater than that of the organic materials in the prior art. The rubber ring 142 and the thermal pad 143 are of high quality, so heat can be conducted more quickly from the gas spray head 250 to the mounting substrate 220 and then carried away by the cooling pipes. This heat conduction process is rapid, reducing the heat accumulation in the gas spray head 250. As a result, the deformation of the lower part of the mounting substrate 220 and the gas spray head 250 is smaller than that in the prior art, and gaps are less likely to form between them. Even if the gas spray head 250 and the mounting substrate 220 undergo slight deformation due to heat, causing the gap between them to affect the heat conduction between the cover film 242 and the mounting substrate 220, since the protruding ring 241 is always in contact with the cover film 242 and is made of metal, it can continue to quickly transfer the heat of the gas spray head 250 to the mounting substrate 220, preventing heat accumulation that would increase the deformation of the gas spray head 250 and the mounting substrate 220, thereby keeping the gap between them at a small level. During the above process, since the raised ring 241 remains in contact with the cover film 242 at the process temperature, it quickly conducts heat between the gas spray head 250 and the mounting substrate 220, while also isolating the gas channels 230 in different ventilation areas.

[0039] This embodiment uses a metal thermoelectric connection component 240 to conduct heat between the gas spray head 250 and the mounting substrate 220. This increases the heat transfer rate between the mounting substrate 220 and the gas spray head 250 compared to existing technologies, thereby reducing the gap between them. Consequently, less plasma enters the gap. Furthermore, since the thermoelectric connection component 240 does not use organic components, its corrosive effect is reduced compared to existing technologies. This avoids the corrosion of the thermoelectric connection component that affects the thermoelectric conduction between the mounting substrate 220 and the gas spray head 250, as well as the gas isolation between different ventilation areas, as is common in existing technologies.

[0040] The bottom surface of the mounting substrate 220 is composed of a first part and a second part. The first part is provided with the raised ring 241, and the second part is the portion of the bottom surface of the mounting substrate 220 without the raised ring 241. A gap will be generated between the bottom surface of the mounting substrate 220 and the cover film 242 at the process temperature. The second part corresponding to the location of the gap and the portion of the mounting substrate 220 exposed in the reaction chamber 200 are both covered with an anodized coating. Since the anodized coating has the characteristic of being resistant to plasma corrosion, covering the bottom surface of the mounting substrate 220 and the portion of the mounting substrate 220 exposed in the reaction chamber 200 with anodized coating can protect the bottom surface of the mounting substrate 220 and the portion of the mounting substrate 220 exposed in the reaction chamber 200 from plasma corrosion. For the second portion corresponding to the location where no gap is formed between the mounting substrate 220 and the cover film 242, no anodic oxide coating is applied. Because no anodic oxide coating is applied at this location, the mounting substrate 220 and the cover film 242 can directly conduct electricity, enhancing the electrical conduction between the mounting substrate 220 and the gas spray head 250. Furthermore, since no gap is formed at this location under process temperature, the absence of an anodic oxide coating minimizes the corrosive effect of plasma on the mounting substrate 220. Additionally, the first portion, i.e., the raised ring 241, is also not covered with an anodic oxide coating to avoid affecting the electrical conduction between the mounting substrate 220 and the gas spray head 250. The specific locations where a gap is formed or not formed between the mounting substrate 220 and the cover film 242 are determined based on actual conditions.

[0041] Furthermore, the area of ​​the first end of the outer ring 241 is set to be larger than the area of ​​the first end of the inner ring 242, so as to... Figure 4 For example, the area of ​​the first end of the outermost raised ring 241c is larger than the area of ​​the first end of the middle raised ring 241b, and the area of ​​the first end of the middle raised ring 241b is larger than the area of ​​the first end of the inner raised ring 241a. Since the outer sidewall of the upper electrode assembly can also contact the plasma, the deformation of its outer ring is greater than that of the inner ring. It is easier for a gap to be generated between the mounting substrate 220 and the gas spray head 250. Therefore, by setting a raised ring 242 with a larger area on the outer ring to conduct heat between the cover film 242 and the mounting substrate 220, the heat conduction rate of the outer ring is accelerated, and the heat accumulation on the outer ring of the gas spray head 250 is reduced. This reduces the deformation of the outer ring of the gas spray head 250 and the mounting substrate 220, making it less likely for a significant gap to be generated between their outer rings, and reducing the plasma entering the gap.

[0042] The cover film 242 uniformly covers the top surface of the gas spray head 250 and has a certain thickness to accommodate the raised ring 241. The cover film 242 is always in contact with the raised ring 241 to ensure the thermoelectric conductivity and gas isolation effect of the upper electrode assembly. That is, regardless of whether the upper electrode assembly is processed at room temperature or in a high-temperature process environment, the raised ring 241 is embedded within the cover film 242. Therefore, it can ensure the electrical and thermal conductivity between the mounting substrate 220 and the gas spray head 250 while isolating the gas channels 230 in different ventilation areas. In this embodiment, the thickness of the cover film 242 is set to be greater than 100 μm.

[0043] Since the silicon-based gas spray head 250 is generally single crystal, the second end 2412 of the protrusion ring 241 has the covering film 242 between it and the top surface of the gas spray head 250 at room temperature. At the process temperature, even after the mounting substrate 220 and the gas spray head 250 undergo slight deformation, the second end 2412 of the protrusion ring 241 will never contact the gas spray head 250, thereby preventing the second end 2412 of the protrusion ring 241 from touching the top of the gas spray head 250 and causing it to break when the upper electrode assembly deforms.

[0044] Furthermore, the raised ring 241 is made of the same material as the mounting substrate 220 to reduce metal contamination within the reaction chamber 100. The mounting substrate 220 is generally made of metal; for example, in this embodiment, it is made of aluminum. Therefore, the raised ring 241 is also made of aluminum, and it is integrally formed with the mounting substrate 220, reducing the impact of welding or other connection methods on the thermoelectric conductivity of the mounting substrate 220. In other embodiments, other metal materials with a hardness not less than that of the cover film 242 can also be used as the raised ring 241.

[0045] Furthermore, the material of the cover film 241 is the same as that of the mounting substrate 220, that is, the cover film 241 is an aluminum film, so that the expansion coefficient and thermal conductivity coefficient of the mounting substrate 220 and the cover film 241 are the same. At this time, the material of the cover film 241 and the raised ring 241 are also the same, so that the heat of the gas spray head 250 passes through the aluminum cover film 241 and the aluminum raised ring 241 in sequence, and reaches the aluminum mounting substrate 220. The cover film 241 is in close contact with the gas spray head 250. In this process, the heat is transferred in the same metal material, the heat conduction rate is fast, and no heat accumulation will occur. The deformation of the mounting substrate 220 and the gas spray head 250 is small, and gaps are not easily generated between the mounting substrate 220 and the gas spray head 250.

[0046] Before assembling the electrode assembly, the cover film 241 is applied to the top surface of the gas spray head 250 by thermal evaporation or vapor deposition.

[0047] The mounting base plate 220 and the gas spray head 250 are connected and fixed by a fastening device. In this embodiment, multiple corresponding connection holes are provided on the bottom surface of the mounting base plate 220 and the top surface of the gas spray head 250. The connecting holes are also provided on the cover film 242 on the top surface of the gas spray head 250. At room temperature, bolts are used to pass through these connection holes to connect the mounting base plate 220 and the gas spray head 250, so that the bottom surface of the mounting base plate 220 is in contact with the cover film 242.

[0048] like Figures 2 to 4 As shown, in this embodiment, each raised ring 241 includes two concentric raised sub-rings. The two raised sub-rings are distributed in an inner and outer ring pattern to improve the thermoelectric conductivity and gas isolation effect of the thermoelectric connection assembly 240. Specifically, by setting two raised sub-rings, the heat conduction area between the gas spray head 250 and the mounting substrate 220 is expanded, further accelerating the heat conduction rate and reducing the impact of heat accumulation on the deformation of the gas spray head 250 and the mounting substrate 220, thereby further reducing the gap between them. Furthermore, by setting two raised sub-rings, the contact between the raised ring 241 and the covering film 242 is further ensured, thereby better isolating different ventilation areas. In other embodiments, more raised sub-rings can be set to obtain better thermoelectric conductivity and gas isolation effect of the thermoelectric connection assembly 240.

[0049] In this embodiment, the thermoelectric connection assembly 240 divides the upper electrode assembly into four concentric ventilation zones, such as... Figure 4 and Figure 5 As shown, the area within the first raised ring 241a is the first ventilation area A; the area between the second raised ring 241b and the first raised ring 241a is the second ventilation area B; the area between the third raised ring 241c and the second raised ring 241b is the third ventilation area C; and the area outside the third raised ring 241c is the fourth ventilation area D. Multiple gas channels 230 are distributed within these ventilation areas. The gas channels 230 in different ventilation areas are not interconnected. As mentioned above, due to the presence of the metal thermoelectric connection component 240, gaps are less likely to occur between the mounting substrate 220 and the cover film 242. Furthermore, since the raised ring 241 and the cover film 242 always maintain contact, even if a gap occurs between the mounting substrate 220 and the cover film 242, gas in one gas channel 230 cannot enter the gas channels 230 of other ventilation areas through that gap. This achieves isolation of the ventilation areas and provides a basis for independent gas control in different ventilation areas. In other embodiments, N raised rings 241 concentric with the mounting substrate 220 can be provided to divide the upper electrode assembly into N+1 concentric ventilation areas, with multiple gas channels 230 distributed in these ventilation areas.

[0050] The present invention also provides a plasma processing apparatus, comprising: a reaction chamber 200, wherein the reaction chamber 200 has a base 180 for placing a substrate 170 to be processed, and an upper electrode assembly disposed opposite to the base 180 and located at the top of the reaction chamber 200; a radio frequency power supply connected to the base 180, and a reaction gas supply channel connected to the gas channel 230 of the upper electrode assembly, thereby delivering external process gas into the gas channel 230 and then into the reaction chamber 200; at least one protruding ring 242 dividing the upper electrode assembly into at least two ventilation areas to achieve independent gas control in different ventilation areas.

[0051] The present invention also provides a method for assembling an upper electrode assembly, for assembling the above-mentioned upper electrode assembly, comprising the following steps: A cover film 242 is uniformly covered on the top surface of the gas spray head 250 by thermal evaporation or vapor deposition, and multiple raised rings 241 concentric with the mounting substrate 220 are integrally formed on the bottom surface of the mounting substrate 220 along the circumferential direction. An anodized coating is applied to the second portion at the location where a gap is formed between the bottom surface of the mounting substrate 220 and the cover film 242 at the process temperature, and to the portion of the mounting substrate 220 exposed in the reaction chamber 200; wherein the bottom surface of the mounting substrate 220 is composed of the second portion and the first portion having a raised ring 241. The protruding ring 241 is pressed and embedded into the cover film 242, thereby separating the mounting base plate 220 and the gas spray head 250 into multiple ventilation areas. By passing bolts through the corresponding connection holes on the gas spray head 250 and the mounting base plate 220, the gas spray head 250 and the mounting base plate 220 are connected and fixed to form an upper electrode assembly.

[0052] The gas spray head 250 and the mounting base plate 220 are provided with multiple through gas channels 230. When connecting the gas spray head 250 and the mounting base plate 220, the corresponding gas channels 230 are aligned so that each gas channel 230 passes through the upper electrode assembly from top to bottom.

[0053] The aforementioned upper electrode assembly is assembled into the reaction chamber 200, and the reaction chamber 200 is used for plasma etching. During the process, the heat of the high-temperature plasma is conducted to the gas spray head 250, and then passes through the metal cover film 241 and the metal protrusion ring 241 in sequence, reaching the metal mounting substrate 220. The heat is carried away by the cooling pipes in the mounting substrate 220. During this process, the heat conduction rate is fast and no heat accumulation occurs. The deformation of the mounting substrate 220 and the gas spray head 250 is minimal, and gaps are not easily generated between the mounting substrate 220 and the gas spray head 250. Furthermore, the protrusion ring 241 and the cover film 242 always remain in contact, thereby achieving gas isolation and stable thermoelectric conduction.

[0054] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. An upper electrode assembly disposed at the top of the reaction chamber of a plasma processing device, characterized in that, include: A mounting substrate and a gas spray head are connected and fixed by a fastening device. Multiple gas channels are dispersedly arranged in the upper electrode assembly, each gas channel penetrating both the mounting substrate and the gas spray head, and the gas channels are used to introduce process gas into the reaction chamber. A thermoelectric connection assembly is disposed between the mounting substrate and the gas spray head. The thermoelectric connection assembly includes a raised ring and a covering film. The covering film is disposed on the top surface of the gas spray head. The raised ring is arranged circumferentially along the mounting substrate. The raised ring includes a first end and a second end opposite to each other. The first end is fixed to the bottom surface of the mounting substrate, and the second end is embedded in the covering film and always maintains contact with the covering film, used to divide the upper electrode assembly into at least two ventilation areas. Both the raised ring and the covering film are made of metal.

2. The upper electrode assembly as described in claim 1, characterized in that, The longitudinal section of the protruding ring is conical, with the area of ​​its first end being larger than the area of ​​its second end.

3. The upper electrode assembly as described in claim 1, characterized in that, After the second end of the protruding ring is embedded in the covering film, the covering film is between the second end of the protruding ring and the top surface of the gas spray head.

4. The upper electrode assembly as described in claim 1, characterized in that, The covering film evenly covers the top surface of the gas spray head, and the thickness of the covering film is greater than 100 μm.

5. The upper electrode assembly as described in claim 1, characterized in that, The cover film and the mounting substrate are made of the same material.

6. The upper electrode assembly as described in claim 5, characterized in that, Both the raised ring and the cover film are made of aluminum. The raised ring is integrally formed with the mounting substrate, and the cover film is applied to the top surface of the gas spray head by thermal evaporation or vapor deposition.

7. The upper electrode assembly as claimed in claim 1, characterized in that, The bottom surface of the mounting substrate is composed of a first part and a second part. The first part is provided with the protruding ring. The portion of the mounting substrate exposed in the reaction chamber and the second part corresponding to the location where a gap is generated between the bottom surface of the mounting substrate and the cover film at the process temperature are both covered with an anodized coating.

8. The upper electrode assembly as claimed in claim 1, characterized in that, The raised rings are configured as N, and the raised rings are concentrically arranged with the mounting substrate. These raised rings divide the upper electrode assembly into N+1 concentric ventilation areas, and the gas channels are distributed in the ventilation areas.

9. The upper electrode assembly as described in claim 8, characterized in that, The area of ​​the first end of the outer ring is larger than the area of ​​the first end of the inner ring.

10. The upper electrode assembly as claimed in claim 8, characterized in that, Each of the protruding rings includes at least two concentric protruding sub-rings.

11. A plasma processing device, characterized in that, include: The reaction chamber has a base for placing a substrate to be processed, and an upper electrode assembly as described in any one of claims 1-10 is disposed opposite to the base and located at the top of the reaction chamber; an radio frequency power supply is connected to the base, a reaction gas supply channel is connected to the gas channel of the upper electrode assembly, and the protruding ring divides the upper electrode assembly into multiple ventilation areas to achieve independent gas control in different ventilation areas.

12. A method for assembling an upper electrode assembly, characterized in that, Includes the following steps: A covering film is placed on the top surface of the gas spray head, and a raised ring is provided circumferentially on the bottom surface of the mounting substrate. The protruding ring is pressed and embedded into the cover film, thereby separating the mounting substrate and the gas spray head into multiple ventilation areas; both the protruding ring and the cover film are made of metal; the gas spray head and the mounting substrate are connected and fixed by a fastening device to form an upper electrode assembly; wherein, the gas spray head and the mounting substrate are provided with multiple through gas channels, and the corresponding gas channels are aligned when connecting the gas spray head and the mounting substrate.

13. The assembly method of the upper electrode assembly as described in claim 12, characterized in that, The covering film is uniformly covered on the top surface of the gas spray head by thermal evaporation or vapor deposition.

14. The assembly method of the upper electrode assembly as described in claim 12, characterized in that, After a raised ring is provided on the bottom surface of the mounting substrate and before the raised ring is embedded in the cover film, an anodized coating is applied to the second portion corresponding to the part of the mounting substrate exposed in the reaction chamber and the location where a gap is formed between the bottom surface of the mounting substrate and the cover film at the process temperature.

15. The assembly method of the upper electrode assembly as described in claim 12, characterized in that, Multiple concentric raised rings are provided on the bottom surface of the mounting substrate.

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