Lower electrode assembly and plasma processing device

Abstract

A lower electrode assembly and a plasma processing device are disclosed. The lower electrode assembly includes: a first base for supporting a substrate, wherein a first cooling channel is provided therein; a second base disposed around the first base, forming two separate components, and the second base is provided with a second cooling channel; a heat insulation structure disposed between the first base and the second base, for independently controlling the temperature of the first base and the second base; an edge ring assembly disposed above the second base; and a device plate disposed below the first base and the second base, wherein the first base and the second base are fixedly connected to the device plate. The lower electrode assembly can independently control the temperature of the edge ring assembly.

Description

Technical Field

[0001] This invention relates to the field of semiconductors, and more particularly to a lower electrode assembly and a plasma processing apparatus. Background Technology

[0002] In plasma processing equipment, the plasma density distribution within the reaction chamber is directly proportional to the etching rate of the substrate; higher plasma density results in a higher etching rate, and lower plasma density results in a lower etching rate. Due to the plasma gas flow, the plasma density decreases in the central region of the substrate and increases at the edges, leading to a decrease in the etching rate in the central region and an increase in the etching rate at the edges, resulting in uneven etching rates on the substrate.

[0003] To address the aforementioned issues, an edge ring assembly is positioned around the periphery of the substrate. This effectively expands the radius of the substrate outwards, generating plasma under the same conditions above the edge ring assembly as above the substrate. This effectively extends the plasma distribution edge above the substrate to the outer wall of the edge ring assembly, increasing the plasma distribution range and broadening the plasma density distribution curve on the substrate surface. This results in a smoother plasma density distribution on the substrate, leading to a more uniform plasma density distribution and ensuring the uniformity of the etching process in both the edge and center regions.

[0004] However, the temperature control of existing edge ring assemblies mainly relies on the temperature control system of the substrate supporting the substrate, which means that the temperature of the edge ring assembly can only passively follow the changes in its surrounding environment. Summary of the Invention

[0005] The purpose of this invention is to provide a lower electrode assembly and a plasma processing device that can precisely and independently control the temperature of the edge ring assembly.

[0006] To achieve the above objectives, the present invention provides a lower electrode assembly, comprising: a first base for supporting a substrate, wherein a first cooling channel is provided therein; a second base disposed around the first base, being two separate components from the first base, wherein a second cooling channel is provided therein; a heat insulation structure disposed between the first base and the second base, for enabling independent temperature control of the first base and the second base; an edge ring assembly disposed above the second base; and a device plate disposed below the first base and the second base, wherein the first base and the second base are fixedly connected to the device plate.

[0007] Optionally, it may also include an edge ceramic layer formed on the surface of the second base, the edge ceramic layer having a thickness of 0.5 mm to 10 mm.

[0008] Optionally, the thickness of the edge ceramic layer is greater than or equal to 0.5 mm and less than or equal to 5 mm.

[0009] Optionally, the edge ceramic layer is formed by a sintering process.

[0010] Optionally, it also includes: an edge adjustment electrode disposed within the edge ceramic layer, used to adjust the thickness of the plasma sheath layer in the edge region of the substrate.

[0011] Optionally, it also includes: an edge adsorption electrode disposed within the edge ceramic layer for electrostatic adsorption of the edge ring assembly.

[0012] Optionally, the edge adjustment electrode and the edge adsorption electrode are arranged vertically; or, the edge adjustment electrode and the edge adsorption electrode are in the same plane and separated from each other.

[0013] Optionally, it also includes: an edge helium vent penetrating the second base and the edge ceramic layer, the edge helium vent being used to deliver heat-conducting gas to the underside of the edge ring assembly.

[0014] Optionally, it may also include: a substrate ceramic layer located on the surface of the first substrate for supporting the substrate; and a substrate adsorption electrode disposed within the substrate ceramic layer for electrostatically adsorbing the substrate.

[0015] Optionally, it also includes a substrate radio frequency source connected to the device board.

[0016] Optionally, it may also include: a substrate radio frequency electrode disposed within the substrate ceramic layer; and a substrate radio frequency source connected to the substrate radio frequency electrode.

[0017] Optionally, the substrate ceramic layer may be made of alumina, aluminum nitride, or sapphire; the edge ceramic layer may be made of alumina, aluminum nitride, or sapphire.

[0018] Optionally, the heat insulation structure is the gap between the first base and the second base.

[0019] Optionally, the heat insulation structure further includes a heat insulation layer located within the gap; the heat insulation layer includes Teflon, rubber, or polyimide.

[0020] Optionally, the height of the insulation layer is greater than or equal to the thickness of the second base and less than or equal to the sum of the thicknesses of the first base and the substrate ceramic layer.

[0021] Optionally, the first base is fixedly connected to the device board via a first fastener; the second base is fixedly connected to the device board via a second fastener.

[0022] Optionally, the edge ring assembly includes a focusing ring.

[0023] Optionally, the edge ring assembly further includes: a fixing ring disposed around the focusing ring; the fixing ring is fixedly connected to the second base by a third fastener.

[0024] Accordingly, the present invention also provides a plasma processing apparatus, comprising: a reaction chamber; and the aforementioned lower electrode assembly disposed within the reaction chamber.

[0025] Optionally, the plasma processing device is an inductively coupled plasma processing device, and the reaction chamber includes a reaction chamber sidewall; the inductively coupled plasma processing device further includes: an insulating window disposed above the reaction chamber sidewall; an inductor coil disposed above the insulating window; and a radio frequency power source connected to the inductor coil.

[0026] Optionally, the plasma processing device is an inductively coupled plasma processing device, further comprising: a gas spray head disposed at the top of the reaction chamber and opposite to the lower electrode assembly; and a radio frequency power source connected to the gas spray head or the first base.

[0027] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0028] In the lower electrode assembly provided by this invention, since the first base and the second base are two separate components, and a heat insulation structure is provided between the first base and the second base, temperature cross-contamination between the first base and the second base is not easily achieved. Due to the presence of the heat insulation structure, the first cooling channel within the first base is used only for temperature control of the substrate and does not affect the temperature of the edge ring assembly. Similarly, the second cooling channel within the second base is used only for temperature control of the edge ring assembly and does not affect the temperature of the substrate; the two are independent of each other and do not affect each other.

[0029] Furthermore, since the first and second bases are independent of each other, the edge ceramic layer can be formed on the surface of the second base using a process without the need for an additional component as the edge ceramic layer. The edge ceramic layer formed by this process can be made thinner, and there is no need to add a thermal pad between the edge ceramic layer and the second base to improve thermal conductivity. Therefore, more heat is transferred from the second cooling channel to the edge ring assembly, which is beneficial for better and faster temperature control of the edge ring assembly. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a lower electrode assembly;

[0031] Figure 2 This is a schematic diagram of the structure of a lower electrode assembly according to the present invention;

[0032] Figure 3 This is a schematic diagram of another lower electrode assembly according to the present invention;

[0033] Figure 4 This is a schematic diagram of another lower electrode assembly of the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of another lower electrode assembly of the present invention;

[0035] Figure 6 This is a schematic diagram of the structure of a plasma processing device according to the present invention;

[0036] Figure 7 This is a schematic diagram of another plasma processing device according to the present invention. Detailed Implementation

[0037] The following will be combined with the appendix in the embodiments of the present invention. Figure 1 ~Attached Figure 7 The technical solutions, structural features, objectives and effects achieved in the embodiments of the present invention will be described in detail.

[0038] 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.

[0039] 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.

[0040] As described in the background section, existing edge ring assemblies are difficult to control independently in terms of temperature. Figure 1As shown, a cooling channel 35 is provided within the base 33 for conveying coolant; a substrate ceramic layer 30 is disposed above the base 33. The base 33 typically includes a central region A and an edge region B located around the central region A, with the central region A protruding relative to the edge region B. The area above the central region A is used to support the substrate W, and the area above the edge region B is used to support an edge ring assembly 34.

[0041] Since the edge ring assembly 34 is disposed above the edge region B of the base 33, its temperature mainly depends on the temperature of the base 33, making independent temperature control difficult and resulting in temperature crosstalk between the substrate W and the edge ring assembly 34. In actual processing, for better surface treatment of the substrate W, the temperature of the edge ring assembly 34 may need to be higher or lower than the temperature of the substrate W. Figure 1 The design lacks flexibility, making it difficult to independently and flexibly control the temperature of the edge ring assembly 34.

[0042] To address this technical problem, the present invention provides a lower electrode assembly and its plasma processing device. This is achieved by setting up independent first and second bases, with the second base located around the first base. A heat insulation structure is provided between the first and second bases. The second base supports the edge ring assembly and contains a second cooling channel for independent and precise temperature control of the edge ring assembly. Detailed description follows:

[0043] Figure 2 This is a schematic diagram of the structure of a lower electrode assembly according to the present invention.

[0044] Please refer to Figure 2 The lower electrode assembly 100 includes: a first base 101 for supporting the substrate W, which has a first cooling channel 102 therein; a second base 103 located around the first base 101, which is a separate component from the first base 101, and has a second cooling channel 104 therein; a heat insulation structure located between the first base 101 and the second base 103 for independently controlling the temperature of the first base 101 and the second base 103; an edge ring assembly 106 located above the second base 103; and a device plate 107 located below the first base 101 and the second base 103, with the first base 101 and the second base 103 fixedly connected to the device plate 107.

[0045] In this embodiment, the first cooling channel 102 is used to transport coolant, which includes water. The coolant in the first cooling channel 102 is used to precisely control the temperature of the substrate W. The second cooling channel 104 is also used to transport coolant, which includes water. The coolant in the second cooling channel 104 is used to precisely control the temperature of the edge ring assembly 106. Since the first base 101 and the second base 103 are two independent components, and a heat insulation structure is provided between the first base 101 and the second base 103, the substrate W and the edge ring assembly 106 can be independently temperature controlled. Therefore, the temperature of the coolant in the first cooling channel 102 and the second cooling channel 104 can be adjusted according to actual process requirements, thereby independently controlling the surface temperature of the substrate W and the temperature of the edge ring assembly 106.

[0046] To better prevent temperature crosstalk between the substrate W and the edge ring assembly 106, in one embodiment, the heat insulation structure is a gap between the first base 101 and the second base 103. In another embodiment, the heat insulation structure further includes a heat insulation layer 110 located within the gap. The material of the heat insulation layer 110 includes Teflon, rubber, or polyimide. Furthermore, the heat insulation layer 110 not only has good heat insulation performance but also good corrosion resistance. Thus, even if a small amount of plasma leaks into the gap between the first base 101 and the second base 103, the heat insulation layer 110 is not easily corroded. Therefore, the heat insulation layer 110 can effectively isolate the first base 101 and the second base 103, preventing temperature interference between them.

[0047] In this embodiment, the lower electrode assembly 100 further includes: a substrate ceramic layer 180 located on the surface of the first base 101; and an edge ceramic layer 105 formed on the surface of the second base 103. The substrate ceramic layer 180 is made of alumina, aluminum nitride, or sapphire. The edge ceramic layer 105 is made of alumina, aluminum nitride, or sapphire.

[0048] In this embodiment, the heat insulation layer 110 is not only located in the gap between the first base 101 and the second base 103, but also extends upward to a portion of the sidewall of the substrate ceramic layer 180. This completely isolates the first base 101 and the second base 103 from each other, making the temperature control capabilities of the first cooling channel 102 and the second cooling channel 104 independent and less likely to interfere with each other. In fact, the insulation layer 110 does not necessarily have to extend upward to the sidewall of the substrate ceramic layer 180, but it must at least cover all the sidewalls of the second base 103. This can isolate the first base 101 and the second base 103, thereby reducing mutual interference between the first base 101 and the second base 103 and improving the independent temperature control capability of the substrate W and the edge ring assembly 106.

[0049] In existing technologies, such as Figure 1 As shown, the base 33 is typically an integral structure, which usually includes a central region A and an edge region B surrounding the central region A. The central region A protrudes relative to the edge region B. Through the sintering process, only the substrate ceramic layer 30 can be formed in the central region A, and it is difficult to form an edge ceramic layer on the top surface of the edge region at the same time. Usually, the edge ceramic layer is added as an additional component. In order to ensure the mechanical strength of the additional component edge ceramic layer, the thickness of the additional edge ceramic layer is relatively thick. Furthermore, the additional edge ceramic layer is an independent component from the upper and lower components. In order to better achieve the thermal conductivity between the additional edge ceramic layer and the upper and lower components, thermal pads need to be set between the additional edge ceramic layer and the upper and lower components respectively. This results in the cooling channel below the edge ring assembly 34 to the edge ring assembly 34 having not only a thick additional edge ceramic layer, but also an additional thermal pad, making the distance between the cooling channel and the edge ring assembly 34 relatively large. Therefore, the cooling capacity of the cooling channel to the edge ring assembly 34 is weak, and the temperature control feedback is slow.

[0050] In this embodiment, since the first base 101 and the second base 103 are two independent components, rather than a single stepped structure, the substrate ceramic layer 180 on the surface of the first base 101 and the edge ceramic layer 105 on the surface of the second base 103 can be formed independently through a sintering process. This avoids the problem of difficulty in sintering the edge ceramic layer 105 on the top surface of the edge region due to the stepped structure of the base, thus eliminating the need for an additional component as the edge ceramic layer 105. The edge ceramic layer 105 formed by the sintering process is relatively thin, for example, the thickness of the edge ceramic layer 105 formed by the sintering process is 0.5 mm to 10 mm, and the thickness of the edge ceramic layer 105 can be the thickness of the endpoint value, that is, the thickness of the edge ceramic layer 105 can be 0.5 mm or 10 mm, or even greater than or equal to 0.5 mm and less than or equal to 5 mm, so that the distance between the second cooling channel 104 and the edge ring assembly 106 is relatively short. Therefore, it is beneficial to quickly adjust the temperature of the edge ring assembly 106 through the second cooling channel 104.

[0051] Furthermore, the edge ceramic layer 105 formed by the sintering process can be directly formed on the surface of the second base 103. Therefore, there is no need to add a thermal pad between the edge ceramic layer 105 and the second base 103 to improve the thermal conductivity between them. This makes the distance between the second cooling channel 104 and the edge ring assembly 106 closer, and makes the temperature control of the edge ring assembly 106 by the second cooling channel 104 faster and more precise.

[0052] In this embodiment, the edge ring assembly 106 includes a focusing ring 106a and a fixing ring 106b, with the fixing ring 106b disposed around the focusing ring 106a. The focusing ring 106a is made of silicon or silicon carbide. The fixing ring 106b is made of ceramic or quartz, and is fixedly connected to the second base 103 via a third fastener (not shown in the figure) passing through the edge ring assembly 106. Because the focusing ring 106a is pressed against the edge ceramic layer 105 by the fixing ring 106b, the thermal conductivity between the focusing ring 106a and the edge ceramic layer 105 is increased.

[0053] In other embodiments, the edge ring assembly 106 is a single integral component.

[0054] In this embodiment, the lower electrode assembly 100 further includes: a substrate adsorption electrode 112 disposed within the substrate ceramic layer 180 for electrostatic adsorption of the substrate W; and an edge adsorption electrode 114 disposed within the edge ceramic layer 105 for electrostatic adsorption of the edge ring assembly 106. Since the substrate ceramic layer 180 is formed by a sintering process, its thickness is relatively thin, resulting in a strong adsorption capacity of the substrate adsorption electrode 112 for the substrate W. Similarly, since the edge ceramic layer 105 is formed by sintering, its thickness is relatively thin, and there is no thermal pad between the edge ceramic layer 105 and the upper and lower components, resulting in a strong adsorption capacity of the edge adsorption electrode 114 for the edge ring assembly 106. The edge adsorption electrode 114 has a strong adsorption capacity for the edge ring assembly 106, which makes the edge ring assembly 106 better adhered to the edge ceramic layer 105 and the contact area larger. Therefore, it is beneficial to further improve the temperature control speed and accuracy of the second cooling channel 104 on the edge ring assembly 106.

[0055] In this embodiment, the lower electrode assembly 100 further includes a device plate 107 disposed below the first base 101 and the second base 103, wherein the first base 101 and the second base 103 are fixedly connected to the device plate 107. The first base 101 is fixedly connected to the device plate 107 by a first fastener 109; the second base 103 is fixedly connected to the device plate 107 by a second fastener 108.

[0056] In this embodiment, the lower electrode assembly 100 further includes: a substrate adsorption power supply 150 electrically connected to the substrate adsorption electrode 112; an edge adsorption power supply 140 electrically connected to the edge adsorption electrode 114; and a substrate radio frequency (RF) source electrically connected to the device board 107. In this embodiment, the substrate RF source includes a source power source 120 and a bias power source 130. The source power source 120 is used to generate plasma, and the bias power source 130 is used to control the bombardment direction of the plasma. In other embodiments, the substrate RF source may be either a source power source or a bias power source.

[0057] Figure 3 This is a schematic diagram of another lower electrode assembly according to the present invention.

[0058] Please refer to Figure 3The lower electrode assembly 200 includes: a first base 201 for supporting the substrate W, which has a first cooling channel 202 therein; a second base 203 located around the first base 201, which is a separate component from the first base 201, and has a second cooling channel 204 therein; a heat insulation structure located between the first base 201 and the second base 203 for independently controlling the temperature of the first base 201 and the second base 203; an edge ring assembly 206 located above the edge ceramic layer 205; and a device plate 207 located below the first base 201 and the second base 203, with the first base 201 and the second base 203 fixedly connected to the device plate 207.

[0059] In this embodiment, the lower electrode assembly 200 further includes: a heat insulation structure (including a heat insulation layer 210), a substrate ceramic layer 280, a substrate adsorption electrode 212, an edge adsorption electrode 214, a first fastener 209, a second fastener 208, a substrate adsorption power supply 250, an edge adsorption power supply 240, and a substrate radio frequency source (source power source 220 and bias power source 230). It should be noted that the materials, functions, and locations of these features are different from those of the previous ones. Figure 2 The implementation methods are the same and will not be repeated here.

[0060] In this embodiment, since the first base 201 and the second base 203 are two independent bases, the first base 201 is provided with a first cooling channel 202, and the second base 203 is provided with a second cooling channel 204. The temperature of the substrate W is controlled by controlling the temperature of the coolant in the first cooling channel 202, and the temperature of the edge ring assembly 206 is controlled by controlling the temperature of the coolant in the second cooling channel 204. The two are independent of each other and do not interfere with each other. Furthermore, the heat insulation structure provided between the first base 201 and the second base 203 is used to further reduce temperature crosstalk between the first base 201 and the second base 203.

[0061] Since the first base 201 and the second base 203 are two independent components, the substrate ceramic layer 280 and the edge ceramic layer 205 can be formed by sintering processes, respectively. Since the substrate ceramic layer 280 and the edge ceramic layer 205 formed by the sintering process are both thin, the substrate W can be well adsorbed by the substrate adsorption electrode 212, and the edge ring assembly 206 can be well adsorbed by the edge adsorption electrode 214.

[0062] and Figure 2Compared to the previous embodiment, the differences include: the lower electrode assembly further includes an edge helium gas port 218 penetrating the second base 203 and the edge ceramic layer 205, the edge helium gas port 218 being used to supply heat-conducting gas to the area below the edge ring assembly 218. The heat-conducting gas includes helium, which has the highest thermal conductivity, facilitating better temperature regulation of the edge ring assembly 206. Furthermore, helium is an inert gas and generally has minimal impact on processes within the plasma processing apparatus.

[0063] and Figure 2 Compared to the previous embodiment, the difference includes an edge adjustment electrode 216 disposed within the edge ceramic layer 205. The edge adjustment electrode 216 is connected to an edge adjustment power supply 228 to adjust the plasma sheath thickness in the edge region of the substrate W, ensuring that the sheath layer at the center of the substrate to be processed has the same height as the area above the focusing ring, thereby improving etching uniformity. In one embodiment, the edge adjustment electrode 216 is an edge radio frequency electrode, and correspondingly, the edge adjustment power supply 228 is an edge radio frequency power supply. In another embodiment, the edge adjustment electrode 216 is a pulsed DC electrode, and correspondingly, the edge adjustment power supply 228 is a pulsed DC power supply.

[0064] Because the edge ceramic layer 205 is relatively thin, the distance between the edge adjustment electrode 216 located in the edge ceramic layer 205 and the edge ring assembly 206 is relatively short, which is beneficial for better adjusting the thickness of the plasma sheath layer in the edge region of the substrate W, thereby better adjusting the uniformity of the treatment effect in the central and edge regions of the substrate W surface.

[0065] In this embodiment, the edge adjustment electrode 216 and the edge adsorption electrode 214 are staggered, minimizing their mutual influence. Furthermore, the edge adjustment electrode 216 and the edge adsorption electrode 214 can be separately arranged on the same horizontal plane, with a smaller distance between the edge adjustment electrode 216 and the edge ring assembly 206, which is beneficial for improving coupling efficiency.

[0066] In this embodiment, the edge ring assembly 206 is a single unit, positioned as a focusing ring around the substrate W. In other embodiments, the edge ring assembly may be composed of several components.

[0067] Figure 4 This is a schematic diagram of another lower electrode assembly of the present invention.

[0068] Figure 4 Examples and Figure 2 and Figure 3The embodiments are similar. Since the first base 301 and the second base 303 are two independent bases, and the first base 301 has a first cooling channel 302, the coolant in the first cooling channel 302 is used to control the temperature of the substrate W, and the second base 303 has a second cooling channel 304, the coolant in the second cooling channel 304 is used to control the temperature of the edge ring assembly 306, the two are independent and do not interfere with each other. Furthermore, the heat insulation structure (including a heat insulation layer 310) provided between the first base 301 and the second base 303 is used to further reduce temperature crosstalk between the first base 301 and the second base 303.

[0069] and Figure 3 Similar to the embodiment, the lower electrode assembly 300 further includes: an edge helium gas port 318, which is used to deliver heat-conducting gas to the lower part of the edge ring assembly 306 to further improve the temperature control of the edge ring assembly 306; an edge adjustment electrode 316, disposed within the edge ceramic layer 305, which is connected to an edge adjustment power supply 328 for adjusting the thickness of the plasma sheath layer in the edge region of the substrate W; and an edge adsorption electrode 314, connected to an edge adsorption power supply 340, for electrostatically adsorbing the edge ring assembly 306.

[0070] Because the edge ceramic layer 305 is thin and has no thermal pad on its surface, the distance between the edge adjustment electrode 316 and the edge ring assembly 306 located within the edge ceramic layer 305 is relatively short. This facilitates better adjustment of the plasma sheath thickness in the edge region of the substrate W, thereby improving the uniformity of the treatment effect in the central and edge regions of the substrate W surface. Furthermore, the thinness of the edge ceramic layer 305 allows the edge adsorption electrode 314 and the edge ring assembly 306 to have better adsorption capacity, which is beneficial for better temperature control of the edge ring assembly 306.

[0071] In this embodiment, the edge adsorption electrode 314 and the edge adjustment electrode 316 are stacked vertically, with the edge adsorption electrode 314 positioned above the edge adjustment electrode 316. This arrangement is significant because if the edge adsorption electrode 314 were positioned below the edge adjustment electrode 316, it would be partially shielded by the edge adjustment electrode 316, making it difficult to effectively adsorb the edge ring assembly 306. Positioning the edge adsorption electrode 314 above the edge adjustment electrode 316 facilitates better adsorption of the edge ring assembly 306, and the radio frequency signal from the edge adjustment electrode 316 can couple to the edge ring assembly 306 across the edge adsorption electrode 314, which is beneficial for better adjustment of the plasma sheath thickness in the edge region of the substrate W.

[0072] In other embodiments, the edge adsorption electrode is located below the edge adjustment electrode.

[0073] Figure 5 This is a schematic diagram of the structure of another electrode assembly of the present invention.

[0074] Figure 5 The embodiment is similar to the one described above in that the coolant in the first coolant channel 402 can precisely control the temperature of the substrate W surface, and the coolant in the second coolant channel 404 can precisely control the temperature of the edge ring assembly 406; the two are independent of each other. To better prevent temperature crosstalk between the first base 401 and the second base 403, an isolation structure is provided between the first base 401 and the second base 403. Furthermore, the substrate adsorption electrode 412, the edge adsorption electrode 414, the edge adjustment electrode 416, the edge adsorption power supply 440, the edge adjustment power supply 428, and the edge helium gas port 418 are... Figure 4 The edge adsorption electrode 314, edge adjustment electrode 316, edge adsorption power supply 340, edge adjustment power supply 328, and edge helium gas hole 318 described in the embodiment have the same position and function, and will not be described again here.

[0075] The differences between this embodiment and the above embodiments include: a substrate RF electrode 438 is disposed within the substrate ceramic layer 480; a substrate RF source (in this embodiment, the substrate RF source includes: a source power source 420 and a bias power source 430) is connected to the substrate RF electrode 438. This arrangement makes the substrate RF source closer to the substrate, which is beneficial to improving the coupling efficiency.

[0076] Accordingly, the present invention also provides a plasma processing apparatus, the plasma processing apparatus comprising: a reaction chamber; and any of the aforementioned lower electrode components disposed within the reaction chamber.

[0077] In one embodiment, the plasma processing device is a capacitively coupled plasma processing device, such as... Figure 6As shown, the capacitively coupled plasma processing device is a device that generates plasma in a reaction chamber through capacitive coupling by a radio frequency power supply applied to an electrode plate for etching. It includes a reaction chamber 11, which has a generally cylindrical sidewall made of metallic material. An opening (not shown) is provided on the sidewall for accommodating the entry and exit of a substrate. A gas spray head 12 and a lower electrode assembly 13 opposite to the gas spray head are disposed within the reaction chamber. The lower electrode assembly 13 supports the substrate. The gas spray head 12 is connected to a gas supply device 19 for supplying reactive gas to the reaction chamber and also serves as the upper electrode of the reaction chamber. A reaction region is formed between the upper electrode and the lower electrode assembly. At least one power source 14 is applied to one of the upper or lower electrode components 13 through a matching network (not shown in the figure), generating a radio frequency electric field between the upper and lower electrode components to dissociate the reactant gas into plasma. A bias power source 15 is applied to the lower electrode component 13 to control the bombardment direction of the plasma. The plasma contains a large number of active particles such as electrons, ions, excited-state atoms, molecules, and free radicals. These active particles can undergo various physical and chemical reactions with the surface of the substrate, changing the morphology of the substrate surface, thus completing the etching process. An exhaust pump 18 is also provided below the reaction chamber 11 to discharge reaction byproducts from the reaction chamber and maintain the vacuum environment of the reaction chamber. In this embodiment, the power source 14 and the bias power source 15 constitute the substrate radio frequency source.

[0078] In another embodiment, the plasma processing device is an inductively coupled plasma processing device, such as... Figure 7 As shown, the inductively coupled plasma processing device is a device that uses the energy of a radio frequency (RF) power supply to enter the reaction chamber through an inductor coil in the form of magnetic field coupling, thereby generating plasma for etching. The inductively coupled plasma reactor includes a reaction chamber 21, which has a generally cylindrical sidewall made of metallic material. An opening (not shown) is provided on the sidewall for accommodating the entry and exit of a substrate. An insulating window 27 is provided above the sidewall, and an inductively coupled coil 29 is positioned above the window 27. A power source 28 applies RF voltage to the inductively coupled coil 29 through an RF matching network. The inductively coupled plasma reactor also includes a lower electrode assembly 23 located at the bottom of the reaction chamber 21, which supports the substrate.

[0079] In addition, an inner liner 22 is provided inside the reaction chamber to protect the inner wall of the reaction chamber from plasma corrosion. A gas injection port 26 is provided at one end of the side wall of the reaction chamber near the insulating window. In other embodiments, the gas injection port can also be provided in the central region of the insulating window 27. The gas injection port 26 is used to inject the reaction gas into the reaction chamber 21. The radio frequency power source 28 drives the inductively coupled coil 215 to generate a strong high-frequency alternating magnetic field, which ionizes the low-pressure reaction gas in the reaction chamber to generate plasma. A bias power source 25 applies a bias radio frequency voltage to the lower electrode assembly 23 through a radio frequency matching network to control the bombardment direction of charged particles in the plasma. The plasma contains a large number of active particles such as electrons, ions, excited-state atoms, molecules, and free radicals. These active particles can undergo various physical and chemical reactions with the surface of the substrate, changing the morphology of the substrate surface, i.e., completing the etching process. In this embodiment, the bias power source 25 serves as the radio frequency source for the substrate.

[0080] Whether it's a capacitively coupled plasma (CCP) processing device or an inductively coupled plasma processing device, the lower electrode assembly is the same as described above. Figures 1 to 5 In any of the structures shown, specifically, the lower electrode assembly includes: a first base for supporting the substrate, which has a first cooling channel therein; a second base located on the periphery of the first base, which is a separate component from the first base, and which has a second cooling channel therein; and a heat insulation structure located between the first base and the second base for independently controlling the temperature of the first base and the second base.

[0081] Because the first and second bases are independent of each other, the edge ceramic layer can be formed on the surface of the second base using a specific process, without the need for an additional component as the edge ceramic layer. The edge ceramic layer formed by this process can be made thinner, and there is no need to add a thermal pad between the edge ceramic layer and the second base to improve thermal conductivity. Therefore, more heat is transferred from the second cooling channel to the edge ring assembly, which facilitates better and faster temperature control of the edge ring assembly. Furthermore, the independence of the first and second bases means that the first cooling channel in the first base is only used for temperature control of the substrate and does not affect the temperature of the edge ring assembly. Similarly, the second cooling channel in the second base is only used for temperature control of the edge ring assembly and does not affect the temperature of the substrate; the two are independent and do not affect each other.

[0082] To better achieve thermal isolation between the first and second bases, a heat insulation structure is provided between them. Furthermore, since the second and first bases are two independent components, an edge ceramic layer can be formed on the surface of the second base through a sintering process. The thinner edge ceramic layer allows for faster and more accurate temperature control of the edge components within the second cooling channel.

[0083] Furthermore, the edge ring ceramic layer is also equipped with an edge adsorption electrode. The edge ceramic layer is relatively thin, and there is no thermal pad between the edge ceramic layer and the upper and lower components, resulting in a strong adsorption capacity of the edge adsorption electrode for the edge ring assembly. This strong adsorption capacity leads to better adhesion and a larger contact area between the edge ring assembly and the edge ceramic layer, thus further improving the speed and accuracy of temperature control of the edge ring assembly by the second cooling channel.

[0084] An edge adjustment electrode is also provided within the edge ring ceramic layer. Since the edge ceramic layer is relatively thin, the distance between the edge adjustment electrode and the edge ring assembly is relatively short, which is beneficial for better adjusting the thickness of the plasma sheath layer in the edge region of the substrate, thereby better adjusting the uniformity of the treatment effect in the central and edge regions of the substrate surface.

[0085] In addition, an edge helium gas port is provided below the edge ring assembly, which is used to supply heat-conducting gas to the area below the edge ring assembly. The heat-conducting gas includes helium, which has the highest thermal conductivity, thus facilitating better temperature regulation of the edge ring assembly. Furthermore, helium is an inert gas and generally has minimal impact on processes within the plasma processing device.

[0086] 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. A lower electrode assembly, characterized in that, include: The first base is used to support the substrate and has a first cooling channel inside it; The second base is located on the periphery of the first base and consists of two separate components. The second base has a second cooling channel inside. A heat insulation structure is provided between the first base and the second base to allow the first base and the second base to be independently temperature controlled. An edge ring assembly is disposed above the second base; The equipment plate is located below the first base and the second base, and the first base and the second base are fixedly connected to the equipment plate.

2. The lower electrode assembly as described in claim 1, characterized in that, Also includes: An edge ceramic layer is formed on the surface of the second base, the thickness of which is 0.5 mm to 10 mm.

3. The lower electrode assembly as described in claim 2, characterized in that, The thickness of the edge ceramic layer is greater than or equal to 0.5 mm and less than or equal to 5 mm.

4. The lower electrode assembly as described in claim 2, characterized in that, The edge ceramic layer is formed by a sintering process.

5. The lower electrode assembly as described in claim 2, characterized in that, Also includes: An edge adjustment electrode, disposed within the edge ceramic layer, is used to adjust the thickness of the plasma sheath layer in the edge region of the substrate.

6. The lower electrode assembly as described in claim 5, characterized in that, Also includes: An edge adsorption electrode is disposed within the edge ceramic layer for electrostatic adsorption of the edge ring assembly.

7. The lower electrode assembly as described in claim 6, characterized in that, The edge adjustment electrode and the edge adsorption electrode are arranged vertically; or, the edge adjustment electrode and the edge adsorption electrode are in the same plane and separated from each other.

8. The lower electrode assembly as described in claim 2, 5, or 6, characterized in that, Also includes: An edge helium vent extends through the second base and the edge ceramic layer, the edge helium vent being used to deliver thermally conductive gas to the underside of the edge ring assembly.

9. The lower electrode assembly as described in claim 2, characterized in that, Also includes: A substrate ceramic layer, located on the surface of the first substrate, is used to support the substrate; A substrate adsorption electrode is disposed within the ceramic layer of the substrate and is used for electrostatic adsorption of the substrate.

10. The lower electrode assembly as claimed in claim 9, characterized in that, Also includes: The substrate radio frequency source is connected to the device board.

11. The lower electrode assembly as claimed in claim 9, characterized in that, Also includes: The substrate radio frequency electrode is disposed within the substrate ceramic layer; A substrate radio frequency source is connected to the substrate radio frequency electrode.

12. The lower electrode assembly as claimed in claim 9, characterized in that, The substrate ceramic layer is made of aluminum oxide, aluminum nitride, or sapphire; the edge ceramic layer is made of aluminum oxide, aluminum nitride, or sapphire.

13. The lower electrode assembly as claimed in claim 1, characterized in that, The heat insulation structure is the gap between the sidewall of the first base and the sidewall of the second base.

14. The lower electrode assembly as claimed in claim 13, characterized in that, The heat insulation structure further includes a heat insulation layer located within the gap; the heat insulation layer includes Teflon, rubber, or polyimide.

15. The lower electrode assembly as claimed in claim 14, characterized in that, The height of the insulation layer is greater than or equal to the thickness of the second base and less than or equal to the sum of the thicknesses of the first base and the substrate ceramic layer.

16. The lower electrode assembly as claimed in claim 1, characterized in that, The first base is fixedly connected to the device board by a first fastener; the second base is fixedly connected to the device board by a second fastener.

17. The lower electrode assembly as claimed in claim 1, characterized in that, The edge ring assembly includes a focusing ring.

18. The lower electrode assembly as claimed in claim 17, characterized in that, The edge ring assembly further includes a fixing ring disposed around the focusing ring; the fixing ring is fixedly connected to the second base by a third fastener.

19. A plasma processing apparatus, characterized in that, include: reaction chamber; The lower electrode assembly according to any one of claims 1 to 18 is disposed within the reaction chamber.

20. The plasma processing apparatus as claimed in claim 19, characterized in that, The plasma processing device is an inductively coupled plasma processing device, and the reaction chamber includes a reaction chamber sidewall; the inductively coupled plasma processing device further includes: an insulating window disposed above the reaction chamber sidewall; an inductor coil disposed above the insulating window; and a radio frequency power source connected to the inductor coil.

21. The plasma processing apparatus as claimed in claim 19, characterized in that, The plasma processing device is an inductively coupled plasma processing device, and further includes: a gas spray head, disposed at the top of the reaction chamber and opposite to the lower electrode assembly; and a radio frequency power source connected to the gas spray head or the first base.

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