TWI892884B - Plasma processing equipment, upper electrode assembly and assembly method thereof - Google Patents

Abstract

The present invention proposes an upper electrode assembly, which is arranged at the top of the reaction chamber of the plasma processing equipment, comprising: a mounting substrate and a gas shower head, wherein the mounting substrate and the gas shower head are connected and fixed by a fastening device; a thermoelectric connection assembly arranged between the mounting substrate and the gas shower head, wherein the thermoelectric connection assembly comprises a raised ring and a covering film, wherein the covering film is arranged on the top surface of the gas shower head, the raised ring is arranged along the circumference of the mounting substrate, and the raised ring is arranged along the circumference of the mounting substrate. The raised ring includes a first end and a second end. The first end is fixed to the bottom surface of the mounting substrate, and the second end is embedded in the covering film. The second end always maintains contact with the covering film, and is used to separate the upper electrode assembly into at least two ventilation areas. The present invention saves material consumption and stably achieves thermal and electrical conduction between the mounting substrate and the gas shower head, as well as mutual isolation between the ventilation areas, through the raised ring and the covering film that are always in contact.

Description

Plasma processing equipment, upper electrode assembly and assembly method thereof

The present invention relates to the field of semiconductor equipment, and more particularly to a plasma processing device, an upper electrode assembly, and an assembly method thereof.

Vacuum processing equipment is widely used in the semiconductor industry, and plasma processing equipment is a commonly used type of vacuum processing equipment. Plasma processing equipment operates by generating plasma using radio frequency coupled discharge, which is then used to perform deposition, etching, and other processing processes.

Among these, capacitively coupled plasma (CCP) etching equipment, which features upper and lower electrodes, is one of the primary plasma processors. The lower electrode is typically an electrostatic chuck mounted above a susceptor. The upper electrode assembly typically includes a mounting base and a gas shower head positioned below the base. The base and shower head are connected by bolts, and multiple gas channels run through them from top to bottom. These channels are used to transport 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 substrate surface, changing the substrate's topography and completing the etching process.

Currently, to regulate gas flow to different areas of the substrate surface, a rubber ring is placed between the mounting base and the gas showerhead, dividing the lower electrode assembly into at least two concentric ventilation zones. This allows for independent gas flow control in these zones. To ensure stable temperature control of the gas showerhead and the entire RF circuit, a special thermally conductive shim is placed between the mounting base and the gas showerhead to facilitate thermal and electrical conduction. This rubber ring and thermal pad separation method can ensure that the mounting substrate and the gas spray head fit tightly when assembling the plasma equipment at room temperature. However, during the use of the plasma equipment, due to the different thermal expansion coefficients of the mounting substrate and the gas spray head (the mounting substrate is generally metal, and the gas spray head is silicon or silicon carbide), a gap will be generated between the mounting substrate and the gas spray head at high process temperatures, and the plasma below the gas spray head will be affected. The plasma diffuses into the gap and contacts the rubber ring and thermal pad. Over extended use of the CCP etching equipment, the rubber ring and thermal pad are gradually corroded by the plasma. This not only increases material consumption but also affects the contact between the mounting substrate and the gas shower head, affecting the thermal and electrical conductivity between the two, and thus the plasma treatment of the substrate under the gas shower head.

In summary, a new top electrode assembly is needed for plasma processing equipment that can stably achieve gas isolation between different regions of the top electrode assembly at different temperatures and also achieve stable thermoelectric conduction between the mounting substrate and the gas showerhead.

The present invention aims to provide a plasma processing apparatus, an upper electrode assembly, and an assembly method thereof to address the problem in which, when separating different gas zones in the upper electrode assembly, a significant gap is created between the mounting substrate and the gas shower head. Plasma enters this gap, consuming the thermoelectric connection components, thereby affecting the contact between the mounting substrate and the gas shower head and resulting in poor thermal and electrical conductivity between the two.

To achieve the above objectives, the present invention provides an upper electrode assembly, mounted at the top of a reaction chamber in a plasma processing apparatus, comprising: a mounting base and a gas shower head, the mounting base and the gas shower head being connected and fixed by a fastening device; and a thermoelectric connection assembly disposed between the mounting base and the gas shower head. The thermoelectric connection assembly comprises a metal raised ring and a covering film, the covering film being disposed on the top surface of the gas shower head. The raised ring is disposed circumferentially around the mounting base and includes a first end and a second end, opposing each other. The first end is fixed to the bottom surface of the mounting base, while the second end is embedded in the covering film and always maintains contact with the covering film, thereby dividing the upper electrode assembly into at least two ventilation areas.

Optionally, the longitudinal cross-section of the raised ring is conical, with the first end area being larger than the second end area.

Optionally, after the second end of the raised ring is embedded in the covering film, the covering film is located between the second end of the raised ring and the top surface of the gas shower head.

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

Optionally, the covering film and the mounting substrate are made of the same material.

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

Optionally, the raised ring and the covering film are both made of aluminum, the raised ring is integrally formed with the mounting substrate, and the covering film is covered on the top surface of the gas shower head by thermal evaporation or vapor deposition.

Optionally, the bottom surface of the mounting substrate is composed of a first portion and a second portion, the first portion being provided with the raised ring, and the portion of the mounting substrate exposed within the reaction chamber and the second portion corresponding to a location where a gap is generated between the bottom surface of the mounting substrate and the covering film at the process temperature are both covered with an anodic oxide coating.

Optionally, a plurality of gas channels are dispersedly provided in the upper electrode assembly, each gas channel passing through the mounting substrate and the gas shower head, and the gas channel is used to supply process gas into the reaction chamber.

Optionally, the number of the raised rings may be 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.

Optionally, the first end area of the raised ring of the outer ring is larger than the first end area of the raised ring of the inner ring.

Optionally, each of the raised rings comprises at least two concentric raised sub-rings.

A second aspect of the present invention provides a plasma processing apparatus comprising: a reaction chamber having a susceptor for placing a substrate to be processed; an upper electrode assembly disposed opposite the susceptor and located at the top of the reaction chamber; an RF power supply connected to the susceptor; a reaction gas supply channel connected to the gas channel of the upper electrode assembly; and a raised ring that divides the upper electrode assembly into multiple ventilation zones to enable independent gas control in different ventilation zones.

A third aspect of the present invention provides a method for assembling an upper electrode assembly, comprising the following steps: covering the top surface of a gas shower head with a covering film and providing a circumferentially disposed raised ring on the bottom surface of a mounting substrate; press-fitting the raised ring into the covering film to separate the mounting substrate and the gas shower head into multiple ventilation areas; and connecting and securing the gas shower head and the mounting substrate via a fastener to form the upper electrode assembly. The gas shower head and the mounting substrate are provided with multiple penetrating gas channels, and corresponding gas channels are aligned when connecting the gas shower head and the mounting substrate.

Optionally, the covering film is evenly coated on the top surface of the gas shower head by thermal evaporation or vapor deposition.

Optionally, after providing a raised ring on the bottom surface of the mounting substrate and before embedding the raised ring in the covering film, an anodic oxide coating is applied to a portion of the mounting substrate exposed to the reaction chamber and a second portion corresponding to a location where a gap is generated between the bottom surface of the mounting substrate and the covering film at the process temperature.

Optionally, a plurality of concentric raised rings are provided on the bottom surface of the mounting base.

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 by the present invention, a thermoelectric connection assembly is provided between the mounting substrate and the gas shower head, wherein the thermoelectric connection assembly includes a raised ring and a covering film, the covering film being provided on the top surface of the gas shower head, the raised ring being provided along the circumference of the mounting substrate, the second end of the raised ring being embedded in the covering film and controlling the two to always maintain contact at room temperature and process temperature, thereby achieving the purpose of separating the ventilation area; and The thermoelectric conduction between the mounting substrate and the gas shower head and the mutual isolation between the ventilation areas are stably achieved through the raised ring and the covering film that are always in contact. This solution replaces the thermoelectric connection components made of organic materials with thermoelectric connection components made of metal materials, thereby avoiding the consumption of the thermoelectric connection components made of organic materials by plasma. This solution further enhances the heat conduction between the mounting substrate and the gas shower head by using a covering film made of the same material as the mounting substrate. The expansion coefficient and thermal conductivity coefficient of the covering film and the mounting substrate are the same. The number of protrusions is the same, so that heat is transferred from the gas shower head to the mounting substrate more quickly, and the deformation of the gas shower head and the mounting substrate is small, and the gap formed between the two is also small. The amount of plasma entering the gap becomes less, further reducing the consumption of plasma on the thermoelectric connection components; this solution expands the heat conduction area between the gas shower head and the mounting substrate by providing a raised ring including at least two raised sub-rings, further accelerating the heat conduction rate between the two, and reducing the heat accumulation on the gas shower head and the mounting substrate. This reduces deformation, minimizes the gap between the two, and further ensures contact between the raised ring and the cover film, thereby better isolating different ventilation areas. This solution configures the first end area of the outer raised ring to be larger than the first end area of the inner raised ring. This accelerates heat conduction from the outer ring of the upper electrode assembly and reduces heat accumulation in the outer ring of the gas shower head. This reduces deformation of the outer rings of the gas shower head and the mounting base, making it less likely to form a significant gap between the two outer rings, thereby reducing the amount of plasma entering the gap.

100: Reaction Chamber

110: Gas Buffer

120: Installing the Baseboard

130: Gas channel

140: Thermoelectric connection assembly

141: Annular groove

142: Rubber ring

143: Thermal pad

150: Gas shower head

160: Side wall of the reaction chamber

170: Substrate

180: Base

190: Matching Network

200: Reaction Chamber

220: Installing the Baseboard

230: Gas channel

240: Thermoelectric connection assembly

241: Raised Ring

241a: Raised ring

241b: Raised ring

241c: Raised ring

2411: First End

2412: Second End

242: Covering film

250: Gas shower head

A: First ventilation area

B: Second ventilation area

C: Third ventilation area

D: Fourth ventilation area

Figure 1 is a schematic diagram of the structure of a capacitively coupled plasma (CCP) processing device; Figure 2 is a schematic diagram of the structure of the reaction chamber and upper electrode assembly of an embodiment of the present invention; Figure 3 is a schematic diagram of a portion of the structure of the thermoelectric connection assembly of an embodiment of the present invention; Figure 4 is a schematic diagram of a portion of the structure of the upper electrode assembly of an embodiment of the present invention; Figure 5 is a schematic diagram of the bottom view of the mounting substrate of an embodiment of the present invention.

The following will be combined with the drawings in the embodiments of the present invention to provide a detailed description of the technical solutions, structural features, objectives achieved, and effects of the embodiments of the present invention.

It should be noted that the figures are extremely simplified and not to exact proportions. They are intended solely to facilitate and clearly illustrate the embodiments of the present invention and are not intended to limit the conditions for its implementation. Therefore, they have no substantive technical significance. Any structural modifications, proportional changes, or size adjustments, provided they do not affect the efficacy and objectives of the present invention, shall remain within the scope of the technical content disclosed herein.

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

As shown in Figure 1, current capacitively coupled plasma (CCP) processing equipment includes a reaction chamber 100. The reaction chamber 100 includes a gas showerhead 150 and a base 180 disposed opposite the gas showerhead 150, forming a reaction zone between the gas showerhead 150 and the base 180. The gas showerhead 150 is connected and fixed to a mounting substrate 120 above it. Together, the gas showerhead 150 and the mounting substrate 120 serve as the upper electrode assembly of the reaction chamber. Multiple gas channels 130 extend from top to bottom through the upper electrode assembly.

In order to achieve independent control of the gas in different areas within the reaction area, the upper electrode assembly is divided into multiple ventilation areas by multiple thermoelectric connection components 140. The thermoelectric connection components 140 generally include: multiple concentric annular grooves 141 opened on the lower surface of the mounting substrate 120, an annular rubber ring 142 disposed in each annular groove 141 and matching the annular groove 141, and a thermal pad 143 disposed between the lower surface of the mounting substrate 120 and the upper surface of the gas shower head 150. The thermally conductive pad 143 and the rubber ring 142 are horizontally offset. Multiple annular grooves 141 and rubber rings 142 are disposed between the mounting substrate 120 and the gas shower head 150 to separate the upper electrode assembly into multiple concentric ventilation zones. The multiple gas channels 130 are distributed within these ventilation zones. The gas channels 130 within different ventilation zones are not interconnected, and thermal and electrical conduction between the mounting substrate 120 and the gas shower head 150 is achieved through the thermally conductive pad 143.

When assembling the above-mentioned 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 shower head 150. However, during the process, when the temperature of the reaction chamber 100 rises to the process temperature, the plasma below the gas shower head 150 contacts the gas shower head 150, and the high-temperature plasma transfers heat to the gas shower head 150. Due to the contact between the mounting substrate 120 and the gas shower head 150 and the presence of the thermoelectric connection assembly 140, the heat is transferred from the gas shower head 150 to the mounting substrate 120. The mounting substrate 120 is provided with a cooling pipe, thereby transferring the heat transferred to the mounting substrate 120. 20 is taken away. In the above process, both the mounting substrate 120 and the gas shower head 150 are heated. However, since the mounting substrate 120 and the gas shower head 150 are made of different materials, the mounting substrate 120 is generally made of metal, such as aluminum, and the gas shower head 150 is generally made of silicon or silicon carbide. The thermal conductivity and thermal expansion coefficient of the two are different (the thermal conductivity and thermal expansion coefficient of aluminum are both greater than those of silicon or silicon carbide). Therefore, the thermal expansion amplitude of the mounting substrate 120 is greater than that of the gas shower head 150, resulting in an unevenly distributed gap between the mounting substrate 120 and the gas shower head 150. At this time, the heat from the gas shower head 150 is transferred to the mounting substrate 120. When the gas shower head 150 transmits heat to the mounting substrate 120, it needs to rely more on the thermoelectric connection assembly 140. However, since the thermoelectric connection assembly 140 is mainly composed of an organic material rubber ring 142 and a heat conductive pad 143, its heat conduction rate is significantly reduced, resulting in heat accumulation in the gas shower head 150. The heat accumulated in the gas shower head 150 will also affect the lower part of the mounting substrate 120, thereby increasing the deformation of the gas shower head 150 and the lower part of the mounting substrate 120, resulting in an increase in the gap between the mounting substrate 120 and the gas shower head 150. The plasma in the reaction area diffuses into the gap between the two and then contacts the Thermal pad 143 and rubber ring 142, because the plasma includes C4F8, O2 and other gases that are decomposed to form active groups, these active groups will corrode the rubber ring 142 and thermal pad 143 made of organic materials; with the long-term and repeated use of the plasma processing equipment, the thermal pad 143 and rubber ring 14 2 is gradually corroded by the active radicals in the plasma, causing wear of the thermoelectric connection assembly 140 material (thermal gasket 143 and rubber ring 142). As corrosion of the thermal gasket 143 and rubber ring 142 becomes more severe, it also affects the contact and thermal conductivity between the mounting substrate 120 and the gas showerhead 150. When the rubber ring 142 is corroded more severely, it also affects the isolation of the gas channels 130 between different ventilation zones, making it impossible to independently control the gas in different zones.

To solve the above problems, the present invention discloses an upper electrode assembly. A metal raised ring concentric with the mounting substrate is provided on the bottom surface of the mounting substrate, and a metal covering film is provided on the top surface of the gas shower head. When the mounting substrate and the gas shower head are pressed together, the raised ring sinks into the covering film. During the process, the raised ring and the covering film are kept in contact, forming a seal, thereby dividing the upper electrode assembly into at least two ventilation areas. Because the mounting substrate and the gas shower head of the present invention do not require an organic rubber ring or a thermally conductive gasket as a thermoelectric connection component to separate different ventilation areas, the thermoelectric connection assembly of the present invention is free of the risk of being easily damaged by C ₄ F ₈ and O 2 in the plasma. The _upper electrode assembly can also stably isolate the gases between different ventilation zones at different temperatures (especially process temperatures), providing a foundation for independent gas control in different ventilation zones. Furthermore, the metal thermoelectric connection assembly enables stable thermoelectric conduction between the mounting substrate and the gas showerhead.

The following is a detailed description of the embodiments of the present invention with reference to the drawings.

As shown in FIG2 , a reaction chamber 200 of a plasma apparatus according to 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 the upper electrode assembly. An electrostatic chuck is disposed above the base 180 for supporting a substrate 170 to be processed. The electrostatic chuck also serves as a lower electrode. A reaction region is defined between the upper electrode assembly and the lower electrode. Multiple gas channels 230 penetrate the upper electrode assembly from top to bottom. Each gas channel 230 connects the gas buffer 110 to the reaction zone below the gas showerhead 150. The gas buffer 110 is also connected to a process gas source via an external reaction gas supply channel, spraying process gas into the reaction zone through the gas channels 230. Low-frequency and high-frequency power are applied to the upper electrode assembly or the lower electrode via the matching network 190, generating an RF electric field within the reaction zone, dissociating the process gas into plasma, which then initiates an etching reaction on the surface of the substrate 170.

The upper electrode assembly includes: a mounting substrate 220, a disc-shaped gas shower head 250 connected to the bottom of the mounting substrate 220, and a thermoelectric connection assembly 240 disposed between the mounting substrate 220 and the gas shower head 250; the thermoelectric connection assembly 240 includes: a covering film 242 disposed on the top surface of the gas shower head 250, and an annular raised ring 241 disposed along the circumference of the mounting substrate 220, the raised ring 241 being concentric with the mounting substrate 220; as shown in FIG3 As shown, the raised ring 241 includes a first end 2411 and a second end 2412. The first end 2411 is fixed to the bottom surface of the mounting substrate 220, while the second end 2412 is press-fitted and embedded in the cover film 242. The second end 2412 always maintains contact with the cover film 242, thereby dividing the upper electrode assembly into at least two ventilation areas. The multiple gas channels 230 are distributed in these ventilation areas, and the gas channels 230 in different ventilation areas are not connected.

As shown in Figures 3 and 4 , in 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. The covering film 242 is located between the second end 2412 of the raised ring 241 and the top surface of the gas shower head 250. This means that the second end 2412 is in contact with the covering film 242, isolating the ventilation area. The second end 2412 is not in contact with the gas shower head 250, allowing thermal and electrical conduction between the mounting substrate 220 and the gas shower head 250 through the raised ring 241 and covering film 242.

As shown in Figures 2 to 4, the raised ring 241 has a tapered longitudinal cross-section, with the area of its first end 2411 being larger than the area of its second end 2412. Consequently, when assembling the top electrode assembly, the cover film 242 at the second end 2412 is subjected to greater pressure, making it easier for the second end 2412 to press and sink into the cover film 242, thereby dividing the top electrode assembly into at least two ventilation areas (A, B, C, and D in Figure 4). Furthermore, to facilitate the insertion of the second end 2412 into the cover film 242, the hardness of the raised ring 241 is set to be no less than that of the cover film 242.

At the process temperature, the high temperature plasma below the gas shower head 250 contacts the gas shower head 250, and conducts heat into the gas shower head 250. Due to the contact between the mounting substrate 220 and the gas shower head 250 and the presence of the thermoelectric connection assembly 240, heat is conducted from the gas shower head 250 to the mounting substrate 220. The mounting substrate 220 is provided with a cooling pipe to take away the heat conducted to the mounting substrate 220. In this process, due to the gas The top surface of the shower head 250 is covered with a metal coating 242. The heat conduction rate between the metal coating 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 shower head in the prior art. In addition, the coating 242 and the raised ring 241 in the thermoelectric connection assembly 240 of the present invention are also made of metal. The heat conduction rate of the thermoelectric connection assembly 240 is also greater than that of the organic material in the prior art. The rubber ring 142 and the heat conductive pad 143 are provided, so that heat can be transferred from the gas shower head 250 to the mounting base 220 more quickly and then carried away by the cooling pipe. The rapid heat transfer process reduces the heat accumulation in the gas shower head 250, thereby reducing the deformation of the lower portion of the mounting base 220 and the gas shower head 250 compared to the deformation in the prior art, and it is not easy to generate a gap between the two. Even if the gas shower head 250 and the mounting base 220 are Due to slight deformation caused by heat, the gap between the two affects heat conduction between the cover film 242 and the mounting substrate 220. Because the raised ring 241 is always in contact with the cover film 242 and is made of metal, it can continue to quickly transfer heat from the gas shower head 250 to the mounting substrate 220, preventing heat accumulation and causing increased deformation of the gas shower head 250 and the mounting substrate 220, thereby maintaining a relatively small gap between the two. During this process, the raised ring 241 maintains contact with the cover film 242 at the process temperature, rapidly transferring heat between the gas shower head 250 and the mounting substrate 220 while isolating the gas channels 230 in different ventilation areas.

This embodiment provides a metal thermoelectric connection assembly 240 to conduct heat between the gas shower head 250 and the mounting substrate 220. This increases the heat conduction rate between the mounting substrate 220 and the gas shower head 250 compared to the prior art. This reduces the gap between the mounting substrate 220 and the gas shower head 250, and reduces the amount of plasma that enters the gap. Furthermore, after the plasma enters the gap, because the thermoelectric connection assembly 240 does not use components made of organic materials, the plasma's corrosive effects on the thermoelectric connection assembly 240 are reduced compared to prior art. This eliminates the problem of corrosion of the thermoelectric connection assembly in prior art, which would affect thermoelectric conduction between the mounting substrate 220 and the gas showerhead 250, as well as the gas isolation between different ventilation areas.

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 part of the bottom surface of the mounting substrate 220 that is not provided with the raised ring 241. A gap will be generated between the bottom surface of the mounting substrate 220 and the covering film 242 at the process temperature. The second part corresponding to the position where the gap is generated and the part of the mounting substrate 220 exposed in the reaction chamber 200 are covered with an anodic oxide coating. Since the anodic oxide coating has the characteristics of resistance to plasma corrosion, the bottom surface of the mounting substrate 220 and the part of the mounting substrate 220 exposed in the reaction chamber 200 can be protected from being electrolytically eroded by covering with the anodic oxide coating. The second portion corresponding to the position where no gap is generated between the mounting substrate 220 and the covering film 242 is not covered with the anodic oxide coating. Since the anodic oxide coating is not covered there, the mounting substrate 220 and the covering film 242 can be directly conductive thereto, thereby enhancing the electrical conductivity between the mounting substrate 220 and the gas shower head 250. Since no gap is generated at this location at process temperatures, no anodic oxide coating is applied here, minimizing the impact of plasma corrosion on the mounting substrate 220. Furthermore, the first portion, i.e., the raised ring 241, is also not covered with an anodic oxide coating to prevent it from affecting electrical conduction between the mounting substrate 220 and the gas showerhead 250. The specific locations where a gap is generated or not generated between the mounting substrate 220 and the covering film 242 are determined based on actual conditions.

Furthermore, the first end area of the outer ring raised ring 241 is larger than the first end area of the inner ring raised ring 241. Taking Figure 4 as an example, the first end area of the outermost ring raised ring 241c is larger than the first end area of the middle ring raised ring 241b, and the first end area of the middle ring raised ring 241b is larger than the first end area of the inner ring raised ring 241a. Because the outer ring sidewalls of the upper electrode assembly are also exposed to plasma, their deformation is greater than that of the inner ring, making it more likely for a gap to form between the outer ring's mounting substrate 220 and the gas shower head 250. Therefore, a larger raised ring 241 is provided on the outer ring to conduct heat between the cover film 242 and the mounting substrate 220. This accelerates the heat transfer rate of the outer ring and reduces heat accumulation in the outer ring of the gas shower head 250. This, in turn, minimizes the deformation of the outer rings of the gas shower head 250 and the mounting substrate 220, making it less likely for a significant gap to form between the outer rings and reducing the amount of plasma entering the gap.

The covering film 242 evenly covers the top surface of the gas shower head 250 and has a thickness sufficient to accommodate the raised ring 241. The covering film 242 is always in contact with the raised ring 241 to ensure the thermal and electrical conductivity of the upper electrode assembly and the gas isolation effect. That is, whether the upper electrode assembly is processed at room temperature or in a high-temperature process environment, the raised ring 241 remains embedded in the covering film 242. This ensures electrical and thermal conductivity between the mounting substrate 220 and the gas shower head 250 while isolating the gas channels 230 in different ventilation areas. In this embodiment, the covering film 242 is set to a thickness greater than 100 μm.

Because the silicon-based gas shower head 250 is typically single crystal, the cover film 242 is positioned between the second end 2412 of the raised ring 241 and the top surface of the gas shower head 250 at room temperature. Furthermore, at process temperatures, even when the mounting substrate 220 and the gas shower head 250 undergo slight deformation, the second end 2412 of the raised ring 241 remains clear of the gas shower head 250. This prevents the second end 2412 of the raised ring 241 from contacting the top of the gas shower head 250 and causing breakage when the upper electrode assembly deforms.

Furthermore, the raised ring 241 is constructed from the same material as the mounting substrate 220 to minimize metal contamination within the reaction chamber 100. The mounting substrate 220 is typically made of metal. For example, in this embodiment, the mounting substrate 220 is made of aluminum. Therefore, the raised ring 241 is also constructed of aluminum. The raised ring 241 is integrally formed with the mounting substrate 220, minimizing the impact of welding or other connection methods on the thermal conductivity of the mounting substrate 220. In other embodiments, the raised ring 241 may be constructed from other metal materials with a hardness no less than that of the cover film 242.

Furthermore, the material of the covering film 242 is the same as that of the mounting substrate 220, that is, the covering film 242 is an aluminum film, so that the expansion coefficient and thermal conductivity coefficient of the mounting substrate 220 and the covering film 242 are the same. At this time, the covering film 242 and the raised ring 241 are also made of the same material, so that the heat of the gas shower head 250 passes through the aluminum covering film 242, the aluminum material, and the aluminum material. The raised ring 241 reaches the aluminum mounting base 220, and the covering film 242 is tightly attached to the gas shower head 250. During this process, heat is transferred through the same metal material, with a rapid heat conduction rate, preventing heat accumulation. The mounting base 220 and the gas shower head 250 experience minimal deformation, and a gap is unlikely to form between the mounting base 220 and the gas shower head 250.

Before assembling the electrode assembly, the top surface of the gas shower head 250 is covered with the covering film 242 by thermal evaporation or vapor deposition.

The mounting base 220 and the gas shower 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 220 and the top surface of the gas shower head 250. The cover film 242 on the top surface of the gas shower head 250 also has these connection holes. At room temperature, bolts are inserted through these connection holes to connect the mounting base 220 and the gas shower head 250, ensuring that the bottom surface of the mounting base 220 and the cover film 242 are in contact with each other.

As shown in FIG2 to FIG4, each raised ring 241 in this embodiment includes two concentric raised sub-rings, which are arranged in an inner and outer circles to improve the thermoelectric conductive performance and gas isolation effect of the thermoelectric connection assembly 240. Specifically, by providing a double-circle raised sub-ring, the thermal conductivity between the gas shower head 250 and the mounting substrate 220 is expanded. This increases the heat transfer area, further accelerating the heat transfer rate and reducing the impact of heat accumulation on deformation of the gas showerhead 250 and the mounting substrate 220, thereby further reducing the gap between them. Furthermore, the provision of two raised sub-rings further ensures contact between the raised ring 241 and the cover film 242, thereby better isolating different ventilation areas. In other embodiments, more raised sub-rings may be provided to achieve even better thermal conductivity and gas isolation for the thermoelectric connection assembly 240.

The thermoelectric connection assembly 240 of this embodiment divides the upper electrode assembly into four concentric ventilation areas, as shown in Figures 4 and 5. 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 described above, due to the presence of the metal thermoelectric connection assembly 240, a gap is unlikely to form between the mounting substrate 220 and the cover film 242. Moreover, because the raised ring 241 and the cover film 242 always maintain contact, even if a gap is formed between the mounting substrate 220 and the cover film 242, the gas in one gas channel 230 cannot pass through the gap into the gas channels 230 in other ventilation areas. This achieves isolation of the ventilation areas and provides a basis for independent control of the gas in different ventilation areas. In other embodiments, N raised rings 241 may be provided concentrically with the mounting substrate 220 to divide the upper electrode assembly into N+1 concentric ventilation areas, with multiple gas channels 230 distributed within these ventilation areas.

The present invention also provides a plasma processing apparatus comprising: a reaction chamber 200 having a susceptor 180 for placing a substrate 170 to be processed; an upper electrode assembly located at the top of the reaction chamber 200 and opposite the susceptor 180; an RF power supply connected to the susceptor 180; a reaction gas supply channel connected to a gas channel 230 of the upper electrode assembly, thereby transporting external process gas into the gas channel 230 and into the reaction chamber 200; and at least one raised ring 241 separating the upper electrode assembly into at least two ventilation zones to enable independent gas control in different ventilation zones.

The present invention also provides a method for assembling an upper electrode assembly, which is used to assemble the upper electrode assembly, including the following steps: uniformly covering the top surface of the gas shower head 250 with a covering film 242 by thermal evaporation or vapor deposition, and arranging a plurality of protruding rings 241 concentric with the mounting substrate 220 on the bottom surface of the mounting substrate 220 in an integral manner along the circumferential direction; and arranging the second portion of the mounting substrate 220 corresponding to the position where the gap is generated between the bottom surface of the mounting substrate 220 and the covering film 242 at the process temperature and the mounting substrate 220 exposed to the atmosphere. The portion exposed within the reaction chamber 200 is covered with an anodic oxide coating. The bottom surface of the mounting substrate 220 is composed of this second portion and a first portion with a raised ring 241. The raised ring 241 is press-fitted into the covering film 242, thereby separating the mounting substrate 220 and the gas shower head 250 into multiple ventilation areas. Bolts are inserted through corresponding connection holes on the gas shower head 250 and the mounting substrate 220 to connect and secure the gas shower head 250 to the mounting substrate 220, forming the upper electrode assembly.

The gas shower head 250 and the mounting substrate 220 are provided with a plurality of penetrating gas channels 230. When connecting the gas shower head 250 and the mounting substrate 220, the corresponding gas channels 230 are aligned so that each gas channel 230 penetrates the upper electrode assembly from top to bottom.

The 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 transferred to the gas shower head 250, and then passes through the metal coating film 242 and the metal protrusion ring 241 to the metal mounting substrate 220. The cooling pipes are removed during this process. The heat transfer rate is rapid, preventing heat accumulation. The mounting base 220 and the gas shower head 250 experience minimal deformation, making it difficult for a gap to form between them. Furthermore, the raised ring 241 and the covering film 242 maintain contact at all times, achieving gas isolation and stable thermal conductivity.

Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. After reading the above, various modifications and alternatives to the present invention will be apparent to those skilled in the art. Therefore, the scope of protection of the present invention shall be defined by the attached patent application.

110: Gas buffer 160: Reaction chamber sidewall 170: Substrate 180: Base 190: Matching network 200: Reaction chamber 230: Gas channel 240: Thermoelectric junction assembly 241: Raised ring 242: Covering film 250: Gas showerhead

Claims (16)

A top electrode assembly is disposed at the top of a reaction chamber of a plasma processing apparatus. The top electrode assembly comprises: a mounting substrate and a gas shower head, the mounting substrate and the gas shower head being connected and fixed by a fastening device; a thermoelectric connection assembly disposed between the mounting substrate and the gas shower head, the thermoelectric connection assembly comprising a raised ring and a covering film. The covering film is disposed on the top surface of the gas shower head. The raised ring is disposed circumferentially around 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, thereby dividing the top electrode assembly into at least two ventilation areas. The upper electrode assembly as described in claim 1, wherein the longitudinal cross-section of the protruding ring is conical, and the first end area is larger than the second end area. The upper electrode assembly as described in claim 1, wherein after the second end of the raised ring is embedded in the covering film, the covering film is located between the second end of the raised ring and the top surface of the gas shower head. The upper electrode assembly as described in claim 1, wherein the covering film uniformly covers the top surface of the gas shower head, and the thickness of the covering film is greater than 100 μm. The upper electrode assembly as described in claim 1, wherein the cover film and the mounting substrate are made of the same material. The upper electrode assembly as described in claim 5, wherein the raised ring and the covering film are both made of aluminum, the raised ring is integrally formed with the mounting substrate, and the covering film is covered on the top surface of the gas shower head by thermal evaporation or vapor deposition. An upper electrode assembly as described in claim 1, wherein the bottom surface of the mounting substrate consists of a first part and a second part, the first part is provided with the raised ring, and the part of the mounting substrate exposed in the reaction chamber and the second part corresponding to the position where a gap is generated between the bottom surface of the mounting substrate and the covering film at the process temperature are both covered with an anodic oxide coating. The upper electrode assembly as described in claim 1, wherein a plurality of gas channels are dispersedly provided in the upper electrode assembly, each of the gas channels penetrates the mounting substrate and the gas shower head, and the gas channels are used to input process gas into the reaction chamber. As described in claim 8, the upper electrode assembly, wherein the raised rings can be set to N, the raised rings are concentrically arranged with the mounting substrate, and the raised rings divide the upper electrode assembly into N+1 concentric ventilation areas, and the gas channels are distributed in the ventilation areas. The upper electrode assembly as described in claim 9, wherein the first end area of the outer raised ring is larger than the first end area of the inner raised ring. The upper electrode assembly as described in claim 9, wherein each of the raised rings includes at least two concentric raised sub-rings. A plasma processing apparatus comprises: a reaction chamber having a susceptor for placing a substrate to be processed therein; an upper electrode assembly according to any one of claims 1 to 11, disposed opposite the susceptor and located at the top of the reaction chamber; an RF power supply connected to the susceptor; a reaction gas supply channel connected to the gas channel of the upper electrode assembly; and a raised ring separating the upper electrode assembly into multiple ventilation zones to enable independent gas control in different ventilation zones. A method for assembling an upper electrode assembly comprises the following steps: Covering the top surface of a gas shower head with a covering film and providing a circumferentially raised ring on the bottom surface of a mounting base; Compressing and embedding the raised ring into the covering film, thereby separating the mounting base and the gas shower head into multiple ventilation areas; Connecting and securing the gas shower head and the mounting base with a fastener to form the upper electrode assembly; The gas shower head and the mounting base are provided with multiple gas passages extending therethrough, and corresponding gas passages are aligned when connecting the gas shower head and the mounting base. The method for assembling an upper electrode assembly as described in claim 13, wherein the covering film is uniformly covered on the top surface of the gas shower head by thermal evaporation or vapor deposition. The method for assembling an upper electrode assembly as described in claim 13, wherein after a raised ring is provided on the bottom surface of the mounting substrate and before the raised ring is embedded in the covering film, an anodic oxide coating is applied to a second portion of the mounting substrate at a position corresponding to a portion of the mounting substrate exposed in the reaction chamber and a position where a gap is generated between the bottom surface of the mounting substrate and the covering film at a process temperature. A method for assembling an upper electrode assembly as described in claim 13, wherein a plurality of concentric raised rings are provided on the bottom surface of the mounting substrate.