Lower electrode assembly and plasma processing device

Abstract

The invention provides a lower electrode assembly and a plasma processing device, and the lower electrode assembly comprises an electrostatic chuck which is used for supporting a substrate to be processed in a reaction cavity of the plasma processing device; the plurality of gas transmission channels are arranged in a manner of penetrating through the electrostatic chuck; each gas transmission channel comprises a first vent hole, a second vent hole and a first mounting groove which are communicated with one another; wherein the second vent hole is located below the first vent hole, the second vent hole is communicated with the first vent hole through the first mounting groove, and the size of the upper end of the first mounting groove is at least two times larger than that of the lower end of the first vent hole in the direction parallel to the substrate; and a first porous plug is arranged in the first mounting groove. By enlarging the size of the upper end of the first mounting groove in the direction parallel to the substrate, the distance between the substrate and the side wall of the first mounting groove is increased, the electric field intensity in the first vent hole is reduced, and the phenomenon of arc discharge in the first vent hole is effectively reduced.

Description

Technical Field

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

[0002] In the field of semiconductor manufacturing technology, it is often necessary to perform plasma treatment (such as etching or chemical vapor deposition) on a substrate to be processed in a plasma processing device. The plasma processing device includes a vacuum reaction chamber, in which a lower electrode assembly is arranged, and the lower electrode assembly is used to support the substrate to be processed. When the reaction gas is input into the reaction chamber, one or more radio frequency (RF) power supplies can be applied separately to the lower electrode assembly to transmit RF power to the lower electrode assembly, thereby generating an RF electric field inside the reaction chamber to ionize the reaction gas into plasma 10 (such as Figure 1 As shown), the surface of the substrate is processed by chemical and / or physical action between the plasma and the substrate surface.

[0003] In the plasma treatment process, in order to prevent the substrate from overheating, cooling gases such as helium are often used to remove the heat from the substrate to achieve temperature control of the substrate. In order to achieve the above purpose, a number of pores are usually provided in the lower electrode assembly for transmitting the cooling gas through the pores to the back of the substrate, thereby achieving heat transfer between the lower electrode assembly and the substrate. However, as the accuracy of the etching process continues to improve, the voltage of the RF power supply applied to the lower electrode assembly continues to increase. When the RF voltage applied to the lower electrode assembly increases, a high voltage difference is formed between the substrate and the lower electrode assembly, which can easily lead to arcing discharge in the pores inside the lower electrode assembly, resulting in damage to the lower electrode assembly or even scrapping. Summary of the Invention

[0004] The object of the present invention is to provide a lower electrode assembly and a plasma processing device to prevent arc discharge of cooling gas in each gas transmission channel in the lower electrode assembly, reduce the damage of arc discharge to the lower electrode assembly, and thereby extend the service life of the lower electrode assembly.

[0005] To achieve the above-mentioned objectives, the present invention provides a lower electrode assembly, which includes: an electrostatic chuck for supporting a substrate to be processed in a reaction chamber of a plasma processing device; a plurality of gas transmission channels, which are arranged through the electrostatic chuck; each of the gas transmission channels includes a first air vent, a second air vent and a first mounting groove that are interconnected; wherein, the second air vent is located below the first air vent, and the second air vent is interconnected with the first air vent through the first mounting groove, and along a direction parallel to the substrate, the upper end size of the first mounting groove is at least 2 times larger than the lower end size of the first air hole; a first porous plug is arranged in the first mounting groove.

[0006] Optionally, along a direction parallel to the substrate surface, the upper end dimension of the first mounting groove is larger than the lower end dimension thereof.

[0007] Optionally, from a top view, the upper end and the lower end of the first mounting groove are circular, and the diameter of the upper end of the first mounting groove is larger than the diameter of the lower end of the first mounting groove.

[0008] Optionally, the electrostatic chuck includes a base and an insulating layer located on a surface of the base; the base and the insulating layer are connected by an adhesive layer.

[0009] Optionally, the first ventilation hole and the first mounting groove are both located in the insulating layer; and the second ventilation hole passes through the base and the adhesive layer.

[0010] Optionally, the first ventilation hole passes through the insulating layer, the first mounting groove and the second ventilation hole are located in the base and the adhesive layer, and the first mounting groove and the second ventilation hole pass through the base and the adhesive layer.

[0011] Optionally, the lower electrode assembly further includes a second mounting groove, which is located between the second vent hole and the first mounting groove, a second porous plug is disposed in the second mounting groove, and a top end of the second porous plug is connected to a bottom end of the first porous plug.

[0012] Optionally, the upper diameter of the second mounting groove is larger than the lower diameter of the second mounting groove.

[0013] Optionally, the first mounting groove is in a truncated cone shape, and a ratio of an upper diameter to a lower diameter of the truncated cone-shaped first mounting groove is greater than 1.1 and less than 10.

[0014] Optionally, the diameter of the upper end of the first truncated cone-shaped installation groove is less than or equal to 10 mm, and the height of the first truncated cone-shaped installation groove ranges from 1 mm to 20 mm.

[0015] Optionally, the first mounting groove is hemispherical, and the radius of the hemispherical first mounting groove ranges from 0.2 mm to 10 mm.

[0016] Optionally, the first mounting groove is a cylinder, and the diameter of the bottom surface of the cylinder is greater than 4 mm.

[0017] The present invention also provides a plasma processing device, which includes: a reaction chamber; a lower electrode assembly as described above is provided at the bottom of the reaction chamber, for carrying a substrate to be processed; a gas supply assembly, arranged opposite to the lower electrode assembly, for introducing reaction gas into the reaction chamber to perform plasma treatment on the substrate to be processed.

[0018] Optionally, the plasma processing device is a capacitively coupled plasma processing device or an inductively coupled plasma processing device.

[0019] Compared with the prior art, the technical solution of the present invention has at least the following advantages:

[0020] The present invention increases the distance between the back surface of the substrate and the sidewall of the first mounting groove by enlarging the dimension of the upper end of the first mounting groove in a direction parallel to the substrate to at least twice the diameter of the lower end of the first vent hole. Since the voltage difference between the substrate and the sidewall of the first mounting groove remains unchanged, the electric field strength in the first vent hole is reduced, thereby reducing the occurrence of arc discharge in the first vent hole.

[0021] At the same time, by configuring the first mounting groove to have a larger dimension at the upper end parallel to the substrate and a smaller diameter at the lower end, the hollow volume in the base is reduced while effectively preventing arc discharge from occurring in the first vent hole. This not only increases the thermal conductivity and electrical capacitance between the base and the substrate, but also avoids affecting other components installed in the base.

[0022] Furthermore, by arranging a second mounting groove with a second porous plug below the first mounting groove, the voltage between the substrate and the electrostatic chuck can be more concentrated at the first porous plug and the second porous plug, greatly reducing the voltage distributed in the first vent hole, thereby more effectively reducing the arc discharge phenomenon in the first vent hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of a lower electrode assembly;

[0024] Figure 2 for Figure 1 Schematic diagram of the electric field strength in the upper through-holes of the middle and lower electrode assemblies;

[0025] Figure 3 is a schematic diagram of a first embodiment of a lower electrode assembly of the present invention;

[0026] Figure 4 is a schematic diagram of a second embodiment of a lower electrode assembly of the present invention;

[0027] Figure 5 for Figure 4 Schematic diagram of the electric field strength of the lower electrode assembly;

[0028] Figure 6 A schematic diagram of a variation of the second embodiment of the lower electrode assembly of the present invention;

[0029] Figure 7 for Figure 6 Schematic diagram of the electric field strength of the lower electrode assembly;

[0030] Figure 8 is a schematic diagram of a third embodiment of a lower electrode assembly of the present invention;

[0031] Figure 9 for Figure 8 Schematic diagram of the electric field strength of the lower electrode assembly;

[0032] Figure 10 is a schematic diagram of a fourth embodiment of a lower electrode assembly of the present invention;

[0033] Figure 11 is a cross-sectional schematic diagram of a plasma processing device of the present invention;

[0034] Figure 12 It is a cross-sectional schematic diagram of another plasma processing device of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the appended Figure 1 ~Attachment Figure 12 , the technical solutions, structural features, objectives achieved and effects in the embodiments of the present invention are described in detail.

[0036] It should be noted that the drawings are in a very simplified form and use non-precise proportions. They are only used to conveniently and clearly assist in explaining the embodiments of the present invention, and are not used to limit the conditions for the implementation of the present invention. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose that can be achieved by the present invention.

[0037] 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 any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series 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.

[0038] During the plasma treatment process, in order to prevent the substrate W from overheating during the process, cooling gases such as helium are often used to remove the heat from the substrate W, so as to achieve temperature control of the substrate W. Figure 1As shown, a plurality of air holes 140 are provided in the lower electrode assembly 100. The air holes 140 include an upper through hole 141 and a lower through hole 142 interconnected through a first mounting groove 143. The upper through hole 141 is close to the back surface of the substrate W. Cooling gas is transmitted to the back surface of the substrate W through the air holes 140, thereby achieving heat transfer between the lower electrode assembly 100 and the substrate W. However, as the accuracy of the etching process continues to improve, the voltage of the RF power supply applied to the lower electrode assembly continues to increase. When the RF voltage applied to the lower electrode assembly increases to a certain level, a high voltage difference will be formed between the substrate W and the lower electrode assembly 100, which is very likely to cause arc discharge 20 in the upper through hole 141, thereby causing damage to the lower electrode assembly 100 and the substrate W.

[0039] In a specific embodiment, if Figure 2 As shown, Figure 2 for Figure 1 The equipotential line distribution diagram of the upper through hole 141 of the air hole 140 of the lower electrode assembly 100 close to the back surface of the substrate W, Figure 2 The dotted lines in FIG represent equipotential lines. In this embodiment, the potential difference between the substrate W and the lower electrode assembly 100 is set to 1 kV. The result diagram obtained by the simulation experiment (such as FIG Figure 2 shown), Figure 2 The potential difference between adjacent equipotential lines in the graph is 100V. Figure 2 As can be seen in the figure, the equipotential lines in the upper through hole 141 are densely distributed, which means that the electric field strength is strong. The average electric field strength in the upper through hole 141 is about 3.0×10 5 V / m, arc discharge is more likely to occur.

[0040] To address the above-mentioned drawbacks, the present invention adjusts the structure of the air holes. First, the structure of the upper first through-hole remains unchanged to ensure the passage of cooling gas through the first air hole. Second, the end of the lower through-hole near the back of the substrate is expanded, that is, the diameter of the upper end of the first mounting groove is increased to increase the distance between the substrate and the sidewall of the first mounting groove, thereby increasing the capacitance of the first mounting groove, reducing the electric field strength within the upper through-hole, and reducing the probability of arc discharge in the upper through-hole. Detailed description is as follows:

[0041] <First embodiment>

[0042] Based on the above invention ideas, please refer to Figure 3 , Figure 3A cross-sectional view of a lower electrode assembly 200 is provided for a first embodiment, wherein the lower electrode assembly 200 includes: an electrostatic chuck 201 for supporting a substrate W to be processed in a reaction chamber of a plasma processing apparatus; a plurality of gas transmission channels 202, which are arranged through the electrostatic chuck 201, and the bottom ends of the gas transmission channels 202 are connected to a cooling gas source (not shown in the figure) for transmitting cooling gas to the back side of the substrate W; each of the gas transmission channels 202 includes a first air vent 221 that is interconnected and a second air vent 222 located below the first air vent 221; each of the second air vent 222 is interconnected with the first air vent 221 through a first mounting groove 223, and the dimension of the upper end of the first mounting groove 223 in a direction parallel to the substrate is at least twice the dimension of the lower end of the first air vent 221; a first porous plug 224 is arranged in the first mounting groove 223, and the shape of the first porous plug 224 matches the shape of the first mounting groove 223.

[0043] In this embodiment, the upper and lower ends of the first mounting groove 223 are circular when viewed from above. The upper end of the first mounting groove 223 is the end closest to the substrate W, and the lower end of the first mounting groove 223 is the end connected to the second vent hole 222. By enlarging the dimension of the upper end of the first mounting groove 223 parallel to the substrate to at least twice the diameter of the lower end of the first vent hole 221, the distance between the back surface of the substrate W and the sidewall of the first mounting groove 223 is increased, thereby increasing the partial pressure in the first mounting groove 223, reducing the electric field strength within the first vent hole 221, and reducing the occurrence of arc discharge within the first vent hole 221. At the same time, the first porous plug 224 disposed in the first mounting groove 223 also effectively prevents arc discharge of the cooling gas within the first mounting groove 223.

[0044] Specifically, such as Figure 3As shown, the electrostatic chuck 201 includes a base 213 and an insulating layer 211 located on the surface of the base 213; the base 213 and the insulating layer 211 are connected by an adhesive layer 212. In this embodiment, the first vent 221 and the first mounting groove 223 are both located within the insulating layer 211; the second vent 222 penetrates the base 213 and the adhesive layer 212 and connects to the first mounting groove 223, forming a connected gas transmission channel 202, allowing cooling gas to be transmitted to the back side of the substrate W through the second vent 222, the first mounting groove 223, and the first vent 221 in sequence. By setting the first mounting groove 223 in the insulating layer 211, the dielectric constant of the area where the first mounting groove 223 is set in the insulating layer 211 is reduced, so that the voltage in the first vent hole 221 can be more quickly divided by the first porous plug 224 in the first mounting groove 223, thereby reducing the voltage in the first vent hole 221, thereby reducing the electric field strength in the first vent hole 221, and effectively reducing the arc discharge phenomenon in the first vent hole 221.

[0045] Further, if Figure 3 As shown, from a top view, the upper and lower ends of the first mounting groove 223 are circular, and the upper diameter of the first mounting groove 223 is larger than the lower diameter of the first mounting groove 223, so that the cross-section of the first mounting groove 223 forms a shape that is wide at the top and narrow at the bottom. In this embodiment, the shape of the first mounting groove 223 is truncated cone. Optionally, the ratio of the upper diameter to the lower diameter of the truncated cone-shaped first mounting groove 223 is greater than 1.1 and less than 10, and the upper diameter of the truncated cone-shaped first mounting groove is less than or equal to 10 mm. The height of the truncated cone-shaped first mounting groove 223 ranges from 1 mm to 20 mm to avoid the hollow volume of the first mounting groove 223 being too large, which may cause the first mounting groove 223 to interfere with other through holes in the base 213 (such as the lifting hole for setting the lifting pin). By setting the first mounting groove 223 to have a large diameter at the upper end and a small diameter at the lower end, the hollow volume in the base 213 is reduced while effectively preventing arc discharge from occurring in the first vent hole 221. This not only increases the thermal conductivity and capacitance between the base 213 and the substrate W, but also avoids affecting other components installed in the base 213.

[0046] It should be noted that, in other embodiments, the top view shape of the first mounting groove 223 may also be any polygon, such as a square, a pentagon, etc. The present invention does not specifically limit the top view shape of the first mounting groove 223.

[0047] <Second embodiment>

[0048] Figure 4 is a cross-sectional view of the lower electrode assembly 200 of the second embodiment, as shown in FIG. Figure 4As shown, the structure of the lower electrode assembly 200 is substantially the same as that of the first embodiment, with the following differences: the first vent hole 221 penetrates the insulating layer 211, the first mounting groove 223 and the second vent hole 222 are located in the base 213 and the adhesive layer 212, and the first mounting groove 223 and the second vent hole 222 penetrate the base 213 and the adhesive layer 212. Specifically, the top of the first mounting groove 223 is located in the adhesive layer 212 and communicates with the first vent hole 221, while the remaining portion is located in the base 213; the second vent hole 222 is entirely located in the base 213, and the top of the second vent hole 222 is connected to the bottom of the first mounting groove 223, forming a gas transmission channel 202 that penetrates the electrostatic chuck 201, allowing the cooling gas to be transmitted to the back side of the substrate W along the second vent hole 222, the first mounting groove 223, and the first vent hole 221 in sequence. By setting the first mounting groove 223 in the base 213 and the adhesive layer 212, that is, the first mounting groove 223 is located below the insulating layer 211, the distance between the substrate W and the side wall of the first mounting groove 223 is further increased. Since the voltage difference between the substrate and the side wall of the first mounting groove 223 remains unchanged, the electric field strength in the first ventilation hole 221 is reduced, and the probability of arc discharge in the first ventilation hole 221 is reduced.

[0049] Likewise, in this embodiment, Figure 4 As shown, from a top view, the upper and lower ends of the first mounting groove 223 are circular, and the upper diameter of the first mounting groove 223 is larger than the lower diameter of the first mounting groove 223, so that the cross section of the first mounting groove 223 forms a shape that is wide at the top and narrow at the bottom. Optionally, the first mounting groove 223 is a truncated cone, that is, the upper diameter of the first mounting groove 223 is larger than the lower diameter of the first mounting groove 223, and has a trapezoidal cross section that is wide at the top and narrow at the bottom (such as Figure 4 shown).

[0050] The structure of the second embodiment is simulated, and the potential difference between the substrate W and the lower electrode assembly 200 is set to 1kV, and the potential difference between adjacent equipotential lines (dashed lines in the figure) is 100V. The result diagram obtained by the simulation experiment (as shown in FIG Figure 5 shown), Figure 5 The potential difference between adjacent equipotential lines in the graph is 100V. Figure 5 It can be seen from the figure that the equipotential line distribution ratio in the first vent hole 221 of the second embodiment is Figure 2 The electric field lines in the prior art are more sparsely distributed. The simulation results show that the average electric field strength in the first vent hole 221 in the second embodiment is about 1.3×10 5 V / m, compared with the average electric field strength of 3.0×10 5The V / m decreases significantly, which means that the electric field intensity in the first vent hole 221 of this embodiment decreases, thereby preventing the occurrence of arc discharge.

[0051] Further, based on the second embodiment, a modification is made, such as Figure 6 As shown, Figure 6 This is another variation of the second embodiment, specifically: the shape of the first mounting groove 223 in the second embodiment is set to a hemispherical shape, and the radius of the hemispherical first mounting groove 223 ranges from 0.2mm to 10mm. Similarly, the width of the cross-section of the hemispherical first mounting groove 223 decreases from the upper end (i.e., the end connected to the first vent 221) to the lower end (i.e., the end connected to the second vent 222), forming a shape that is wide at the top and narrow at the bottom, increasing the distance from the substrate W to the upper side wall of the first mounting groove 223, increasing the capacitance of the upper end of the first mounting groove 223, and at the same time, since the voltage difference between the substrate and the side wall of the first mounting groove 223 remains unchanged, the electric field strength in the first vent 221 is reduced, reducing the probability of arc discharge in the first vent 221.

[0052] The simulation experiment was conducted on the second embodiment with a hemispherical shape. The potential difference between the substrate W and the lower electrode assembly 200 was set to 1 kV, and the potential difference between adjacent equipotential lines was 100 V. The result diagram obtained by the simulation experiment (as shown in FIG Figure 7 shown), Figure 7 The potential difference between adjacent equipotential lines (dashed lines in the figure) is 100V. Figure 7 It can be seen from the figure that the equipotential line distribution in the first vent hole 221 of the second embodiment with a hemispherical shape is greater than that in the first vent hole 221 of the second embodiment. Figure 2 The electric field lines in the prior art are more sparsely distributed. The simulation results show that the average electric field strength in the first vent hole 221 of the second embodiment with a hemispherical shape is about 1.4×10 5 V / m, compared with the average electric field strength of 3.0×10 5 The V / m decreases significantly, which means that the electric field intensity in the first vent hole 221 of this embodiment decreases, thereby preventing the occurrence of arc discharge.

[0053] <Third embodiment>

[0054] Figure 8 is a cross-sectional view of the lower electrode assembly 200 of the third embodiment, as shown in FIG. Figure 8As shown, the structure of the lower electrode assembly 200 is roughly the same as that in the second embodiment, and the differences include: the first mounting groove 223 is a column, that is, the size of the upper end of the first mounting groove 223 along the direction parallel to the substrate is equal to the size of the lower end along the direction parallel to the substrate, and the size of the cylindrical first mounting groove 223 along the direction parallel to the substrate is greater than 4 mm, so as to ensure that the size of the upper end of the first mounting groove 223 along the direction parallel to the substrate is at least twice the diameter of the lower end of the first vent 221, and at the same time increase the distance from the substrate W to the side wall of the first mounting groove 223, so that the capacitance of the first mounting groove 223 is increased, and the first mounting groove 223 can accommodate more voltage. Since the voltage difference between the substrate and the side wall of the first mounting groove 223 remains unchanged, the electric field strength in the first vent 221 is reduced, and the arc discharge in the first vent 221 is reduced. It should be noted that, in other embodiments, the top view shape of the first mounting groove 223 may be any polygon, such as a square, a pentagon, etc. The present invention does not specifically limit the top view shape of the first mounting groove 223.

[0055] Specifically, taking the first mounting groove as a cylinder as an example, that is, from a top view, the upper end and the lower end of the first mounting groove are both circular. Figure 1 As shown, the bottom diameter of the first mounting groove 143 in the prior art is 3.8 mm (i.e., the diameter size of the first mounting groove commonly used in the prior art). Through simulation experiments, it can be found that the electric field in the upper through hole 141 above the first mounting groove 143 is dense and the electric field intensity is relatively large. The average electric field intensity in the upper through hole 141 is about 3.0×10 5 V / m; and in the third embodiment, as Figure 8 As shown, the bottom diameter of the first mounting groove 223 is set to 4.2 mm, which is at least 10% larger than the diameter of the first mounting groove 143 in the prior art ( Figure 8 dotted line in the figure).

[0056] The structure of the third embodiment is simulated, and the potential difference between the substrate W and the lower electrode assembly 200 is set to 1 kV. The result diagram obtained by the simulation experiment (as shown in FIG Figure 9 shown), Figure 9 The potential difference between adjacent equipotential lines (dashed lines in the figure) is 100V. Figure 9 It can be seen from the figure that the equipotential line distribution ratio in the first vent hole 221 of the third embodiment is Figure 2 The electric field lines in the prior art are more sparsely distributed. The simulation results show that the average electric field strength in the first vent hole 221 in the third embodiment is about 1.8×10 5 V / m, compared with the average electric field strength of 3.0×10 5The V / m decreases significantly, which means that the electric field intensity in the first vent hole 221 of this embodiment decreases, thereby preventing the occurrence of arc discharge.

[0057] It should be noted that the shape of the first mounting groove 223 in the first embodiment can also be set to be hemispherical or cylindrical with a diameter greater than 4 mm, so as to increase the distance from the substrate W to the upper side wall of the first mounting groove 223, thereby increasing the capacitance of the first mounting groove 223 and reducing the electric field strength in the first ventilation hole 221, thereby achieving the purpose of reducing the probability of arc discharge in the first ventilation hole 221.

[0058] <Fourth embodiment>

[0059] Figure 10 is a cross-sectional view of the lower electrode assembly 200 of the fourth embodiment, as shown in FIG. Figure 10 As shown, the structure within the insulating layer 211 of the lower electrode assembly 200 is substantially the same as that of the first embodiment, with the following differences: the lower electrode assembly 200 further includes a second mounting groove 225, which is located between the second vent hole 222 and the first mounting groove 223. A second porous plug 226 is disposed within the second mounting groove 225, and the top end of the second porous plug 226 is connected to the bottom end of the first porous plug 224. By disposing the second mounting groove 225 with the second porous plug 226 below the first mounting groove 223, the voltage between the substrate W and the electrostatic chuck 201 can be more concentrated at the first porous plug 224 and the second porous plug 226, significantly reducing the voltage distributed within the first vent hole 221 and thereby more effectively reducing arcing discharge within the first vent hole 221.

[0060] Specifically, such as Figure 10As shown, the top of the second mounting groove 225 is located in the adhesive layer 212 and the top of the second porous plug 226 installed in the second mounting groove 225 contacts the bottom of the first porous plug 224 installed in the first mounting groove 223, so as to realize the communication between the first porous plug 224 and the second porous plug 226; the remaining parts of the second mounting groove 225 are located at the bottom of the base 213 and connected to the top of the second air hole 222 located in the base 213, forming a gas transmission channel 202 running through the electrostatic chuck 201, so that the cooling gas is transmitted to the back side of the substrate W along the second air hole 222, the second porous plug 226, the first porous plug 224 and the first air hole 221 in sequence. In other embodiments, a connecting hole (not shown) is provided between the first porous plug 224 and the second porous plug 226, that is, the first porous plug 224 and the second porous plug 226 are spaced apart, the upper end of the connecting hole is connected to the first porous plug 224, and the lower end of the connecting hole is connected to the second porous plug 226. The first porous plug 224 and the second porous plug 226 are connected through the connecting hole, so that the cooling gas can be sequentially transmitted to the back side of the substrate W through the second vent 222, the second porous plug 226, the connecting hole, the first porous plug 224 and the first vent 221. Further, as Figure 10 As shown, the upper diameter of the second mounting groove 225 is larger than the lower diameter of the second mounting groove 225, which also increases the capacitance of the upper end of the second mounting groove 225, so that the second mounting groove 225 can accommodate more voltage. Combined with the first mounting groove 223, the electric field strength in the first vent 221 is further reduced, effectively preventing arc discharge in the first vent 221.

[0061] It should be noted that, in this embodiment, the shapes of the first installation groove 223 and the second installation groove 225 can be any one or a combination of two of the shapes in the first to third embodiments.

[0062] Accordingly, the present invention also provides a plasma processing device, please refer to Figure 11 , Figure 11A cross-sectional schematic diagram of a plasma processing apparatus according to an embodiment of the present invention includes a reaction chamber 300. The reaction chamber 300 includes a generally cylindrical reaction chamber sidewall 301 made of a metal material. An opening 302 is provided in the reaction chamber sidewall 301 for allowing a substrate W to enter and exit. A gas showerhead 320 and a lower electrode assembly 310, positioned opposite the gas showerhead 320, are disposed within the reaction chamber 300. The gas showerhead 320 is connected to a gas supply device 325 for supplying reactant gas into the reaction chamber 300. In this embodiment, the gas showerhead 320 serves as the upper electrode of the reaction chamber 300. The lower electrode assembly 310 is similar to the lower electrode assembly described in any of the above embodiments. An electrostatic electrode 313 is disposed within the insulating layer 311 of the lower electrode assembly 310. The electrostatic electrode 313 is connected to a DC voltage source 330 to generate an electrostatic attraction force to support and secure the substrate W to be processed during the process. At the same time, the lower electrode assembly 310 serves as the lower electrode of the reaction chamber 300 . That is, in this embodiment, the reaction chamber 300 is a capacitively coupled plasma processing device, and a reaction region is formed between the upper electrode and the lower electrode.

[0063] During the plasma treatment process of this embodiment, at least one RF power source 350 is applied to one of the upper electrode or the lower electrode through a matching network 352, generating a RF electric field between the upper electrode and the lower electrode to dissociate the reaction gas into plasma. The plasma contains a large number of active particles such as electrons, ions, excited atoms, molecules and free radicals. These active particles can undergo various physical and chemical reactions with the surface of the substrate W to be processed, causing the morphology of the substrate W to change, thereby completing the substrate surface processing process. Figure 11 As shown, an exhaust pump 340 is further provided below the reaction chamber 300 for discharging reaction by-products from the reaction chamber to maintain the environment within the reaction chamber 300 .

[0064] The present invention also provides another plasma processing device, please refer to Figure 12 , Figure 12 A schematic cross-sectional view of another plasma processing apparatus according to an embodiment of the present invention includes a reaction chamber 400 having a generally cylindrical reaction chamber sidewall 401 made of metal. An opening 402 is provided in the reaction chamber sidewall for accommodating the entry and exit of substrates. An insulating window 417 is provided above reaction chamber sidewall 401. An inductively coupled coil 415 is disposed above insulating window 417. An RF power source 418 applies an RF voltage to inductively coupled coil 415 via an RF matching network 416. In this embodiment, reaction chamber 400 is an inductively coupled plasma processing apparatus.

[0065] The reaction chamber 400 is provided with an inner liner 420 to protect the inner wall of the reaction chamber from being corroded by plasma. A gas injection port 403 is provided on one end of the side wall of the reaction chamber 400 near the insulating window 417. In other embodiments, a gas injection port can also be provided in the central area of ​​the insulating window 417. The gas injection port 403 is used to inject the reaction gas into the reaction chamber 400. The radio frequency power of the radio frequency power source 418 drives the inductive coupling coil 415 to generate a strong high-frequency alternating magnetic field, so that the low-pressure reaction gas in the reaction chamber 400 is ionized to generate plasma. A lower electrode assembly 410 is provided at the bottom of the reaction chamber 400. The lower electrode assembly 410 is the lower electrode assembly in any of the above embodiments. An electrostatic electrode 413 is provided within the insulating layer 411 of the lower electrode assembly 410. The electrostatic electrode 413 is connected to a DC voltage source 430 to generate an electrostatic attraction to support and fix the substrate W to be processed during the process.

[0066] Similarly, the plasma generated by the plasma processing device in this embodiment contains a large number of active particles such as electrons, ions, excited atoms, molecules and free radicals. The above-mentioned active particles can undergo various physical and chemical reactions with the surface of the substrate to be processed, causing the morphology of the substrate surface to change, that is, completing the etching process. A biased RF power source 450 applies a biased RF voltage to the base through an RF matching network 452 to control the bombardment direction of the charged particles in the plasma. An exhaust pump 440 is also provided below the reaction chamber 400 to discharge the reaction by-products from the reaction chamber and maintain the vacuum environment in the reaction chamber 400.

[0067] It should be noted that Figure 11 and Figure 12 The lower electrode assembly can be the above Figures 1 to 10 Any design of the lower electrode assembly.

[0068] In summary, the lower electrode assembly and plasma processing apparatus provided by the present invention increase the distance between the back surface of the substrate W and the sidewall of the first mounting groove 223 by enlarging the dimension of the upper end of the first mounting groove 223 in a direction parallel to the substrate to at least twice the diameter of the lower end of the first vent hole 221, thereby increasing the capacitance of the first mounting groove 223. The first mounting groove 223 can accommodate more voltage, reducing the electric field strength within the first vent hole 221, and reducing the occurrence of arc discharge within the first vent hole 221.

[0069] At the same time, by configuring the first mounting groove 223 to have a larger diameter at the upper end and a smaller diameter at the lower end, the hollow volume in the base 213 is reduced while effectively preventing arc discharge from occurring in the first vent hole 221. This not only increases the thermal conductivity and electrical capacitance between the base 213 and the substrate W, but also avoids affecting other components installed in the base 213.

[0070] Furthermore, by providing a second mounting groove 225 with a second porous plug 226 below the first mounting groove 223, the voltage between the substrate W and the electrostatic chuck 201 can be more concentrated at the first porous plug 224 and the second porous plug 226, thereby greatly reducing the voltage distributed in the first vent 221, thereby more effectively reducing the arc discharge phenomenon in the first vent 221.

[0071] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. 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: An electrostatic chuck is used to support a substrate to be processed in a reaction chamber of a plasma processing device; a plurality of gas transmission channels disposed throughout the electrostatic chuck; Each of the gas transmission channels includes a first air vent, a second air vent and a first mounting groove that are interconnected; wherein, the second air vent is located below the first air vent, the second air vent and the first air vent are interconnected through the first mounting groove, and along a direction parallel to the substrate surface, the upper end size of the first mounting groove is at least 2 times larger than the lower end size of the first air hole; a first porous plug is provided in the first mounting groove.

2. The lower electrode assembly according to claim 1, wherein: Along a direction parallel to the substrate surface, the upper end dimension of the first mounting groove is larger than the lower end dimension thereof.

3. The lower electrode assembly according to claim 2, wherein: From a top view, the upper end and the lower end of the first mounting groove are circular, and the diameter of the upper end of the first mounting groove is larger than the diameter of the lower end of the first mounting groove.

4. The lower electrode assembly according to claim 1 or 3, wherein: The electrostatic chuck comprises a base and an insulating layer located on the surface of the base; the base and the insulating layer are connected via an adhesive layer.

5. The lower electrode assembly according to claim 4, wherein: The first ventilation hole and the first mounting groove are both located in the insulating layer; the second ventilation hole passes through the base and the adhesive layer.

6. The lower electrode assembly according to claim 4, wherein: The first vent hole passes through the insulating layer, the first mounting groove and the second vent hole are located in the base and the adhesive layer, and the first mounting groove and the second vent hole pass through the base and the adhesive layer.

7. The lower electrode assembly according to claim 4, wherein: Also includes: The second mounting groove is located between the second vent hole and the first mounting groove. A second porous plug is provided in the second mounting groove, and a top end of the second porous plug is connected to a bottom end of the first porous plug.

8. The lower electrode assembly according to claim 7, wherein: The diameter of the upper end of the second installation groove is larger than the diameter of the lower end of the second installation groove.

9. The lower electrode assembly according to claim 3, wherein: The first mounting groove is in a truncated cone shape, and a ratio of an upper diameter to a lower diameter of the first truncated cone-shaped mounting groove is greater than 1.1 and less than 10.

10. The lower electrode assembly according to claim 9, wherein: The diameter of the upper end of the first truncated cone-shaped installation groove is less than or equal to 10 mm, and the height of the first truncated cone-shaped installation groove ranges from 1 mm to 20 mm.

11. The lower electrode assembly according to claim 2, wherein: The first mounting groove is hemispherical, and the radius of the hemispherical first mounting groove ranges from 0.2 mm to 10 mm.

12. The lower electrode assembly according to claim 1, wherein: The first mounting groove is a cylinder, and the diameter of the bottom surface of the cylinder is greater than 4 mm.

13. A plasma processing device, characterized in that: include: reaction chamber; The bottom of the reaction chamber is provided with a lower electrode assembly according to any one of claims 1 to 12, for carrying a substrate to be processed; The gas supply assembly is arranged opposite to the lower electrode assembly and is used to introduce reaction gas into the reaction chamber to perform plasma treatment on the substrate to be processed.

14. The plasma processing apparatus according to claim 13, wherein: The plasma processing apparatus is a capacitively coupled plasma processing apparatus or an inductively coupled plasma processing apparatus.

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