Electrostatic chuck, lower electrode assembly and plasma processing device

Abstract

The invention provides an electrostatic chuck, a lower electrode assembly and a plasma processing device, the electrostatic chuck is used for bearing a substrate in the plasma processing device, the electrostatic chuck comprises an insulating layer, the upper surface of the insulating layer is opposite to the lower surface of the substrate, and an electrode is arranged in the insulating layer; the plurality of mutually communicated air guide grooves are arranged on the upper surface of the insulating layer; a plurality of vent holes penetrating through the insulating layer are formed in the air guide groove; the air guide cover plate is arranged in the air guide groove, is positioned above the vent holes and covers the corresponding vent holes; and a gas guide channel is arranged in the gas guide cover plate and is communicated with the vent hole and the gas guide groove, so that heat-conducting gas is transmitted between the insulating layer and the substrate through the vent hole and the gas guide channel in sequence. According to the electrostatic chuck, the ventilation holes of the electrostatic chuck are covered with the air guide cover plate provided with the multiple air guide through holes, it is guaranteed that heat conduction gas is evenly diffused on the surface of the electrostatic chuck, and meanwhile the risk that the heat conduction gas discharges at the ventilation holes is reduced.

Description

Technical Field

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

[0002] During plasma processing (such as etching or plasma enhanced chemical vapor deposition, etc.), an electrostatic chuck disposed in a reaction chamber is often used to fix, support and transport semiconductor substrates. The electrostatic chuck uses electrostatic attraction rather than traditional mechanical methods to fix the substrate, which can reduce damage to the substrate caused by mechanical clamping. During the reaction process, a reaction gas is introduced into the reaction chamber, and then radio frequency power is applied to the reaction chamber to activate and dissociate the reaction gas to form plasma, so that the semiconductor substrate can be processed by the plasma.

[0003] In the plasma treatment process, in order to control the temperature of the substrate, helium and other heat-conducting gases are often used as a medium to transfer heat. In order to facilitate the diffusion of helium on the surface of the electrostatic chuck, the electrostatic chuck is usually provided with a number of helium slots, and a number of air holes are provided in each helium slot. Helium and other heat-conducting gases can be transferred between the electrostatic chuck and the substrate through the air holes and the helium slots, thereby achieving heat transfer between the electrostatic chuck and the substrate.

[0004] Since the RF voltage is mainly distributed in a capacitive manner, the relative dielectric constant of a vacuum or gas is 1, and the capacitance is usually small; at the same time, according to the capacitance calculation formula of a flat plate capacitor, the greater the distance between the two plates, the smaller the capacitance. Furthermore, according to the voltage distribution principle of the capacitor, the smaller the capacitance, the greater the voltage obtained. Therefore, in the plasma reaction process, it is found that the position of the helium tank with pores on the electrostatic chuck has the highest discharge risk. The inner wall of the pores can be easily punctured, and then impurity particles are generated in the pores and the helium tank, resulting in contamination of the substrate. Therefore, how to ensure uniform diffusion of the heat-conducting gas while reducing the risk of discharge is a problem that the present invention needs to solve. Summary of the invention

[0005] The object of the present invention is to provide an electrostatic chuck, a lower electrode assembly and a plasma processing device to prevent the heat-conducting gas in the gas guide grooves and the air holes on the electrostatic chuck from being ionized or broken down under the action of radio frequency power to produce discharge, while ensuring the uniformity of the diffusion of the heat-conducting gas, thereby ensuring the temperature uniformity of the substrate.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] The first aspect of the present invention provides an electrostatic chuck for carrying a substrate in a plasma processing device, comprising: an insulating layer, whose upper surface is opposite to the lower surface of the substrate, and an electrode is provided inside the insulating layer; a plurality of mutually connected gas guide grooves, which are arranged on the upper surface of the insulating layer; a plurality of air vents penetrating the insulating layer are provided in the gas guide grooves; an air guide cover plate, which is arranged in the gas guide grooves and is located above the air vents to cover the corresponding air vents; an air guide channel is provided in the air guide cover plate, and the air guide channel connects the air vents and the gas guide grooves, so that the heat-conducting gas is transmitted to between the insulating layer and the substrate through the air vents and the gas guide channel in sequence.

[0008] Preferably, the direction of the air guiding channel is perpendicular to the direction of the vent hole.

[0009] Preferably, the upper surface of the insulating layer includes a plurality of protrusions, and the protrusions are used to support the substrate so that a diffusion gap for the heat-conducting gas is formed between the lower surface of the substrate and the upper surface of the insulating layer.

[0010] Preferably, the top height of the air guide cover plate is located between the bottom surface of the air guide groove and the upper surface of the insulation layer.

[0011] Preferably, the width of the position where the air guide groove is provided with the air vent is greater than the width of the remaining positions of the air guide groove, and there is a gap between the outer side surface of the air guide cover plate and the inner side surface of the air guide groove.

[0012] Preferably, it also includes an annular boss extending horizontally upward along the circumferential edge of the upper surface of the insulating layer, for preventing the escape of heat-conducting gas between the insulating layer and the substrate.

[0013] Preferably, the air guide channel is a plurality of air guide holes arranged at intervals in the horizontal direction of the air guide cover plate, and each of the air guide holes is connected to the air vent hole, so that the heat-conducting gas is evenly diffused.

[0014] Preferably, the diameter of the air guiding channel is smaller than the diameter of the vent hole.

[0015] Preferably, a hollow cavity is formed between the air guide cover plate and the lower surface of the air guide groove, the hollow cavity is communicated with the air vent, and the side wall of the air guide cover plate is provided with at least one air guide port to form an air guide channel.

[0016] Preferably, the air guide cover plate is provided with at least one pair of air guide ports, and each pair of air guide ports is symmetrically arranged on opposite side walls of the air guide cover plate to form an air guide channel that crosses the air guide cover plate.

[0017] Preferably, the insulating layer and the air guide cover plate are both made of ceramic.

[0018] The second aspect of the present invention provides a lower electrode assembly, which includes: the above-mentioned electrostatic chuck, a base for supporting the electrostatic chuck is provided below the electrostatic chuck; a heating layer is provided between the base and the electrostatic chuck, and a plurality of heaters are provided in the heating layer for heating the substrate; a ventilation pipeline is provided in the base, and the ventilation pipeline passes through the base and the heating layer in sequence and is connected to the ventilation hole for transmitting heat-conducting gas.

[0019] Preferably, the base further includes a cooling channel for passing a cooling liquid to cool the base.

[0020] Preferably, it also includes a lifting channel that runs through the electrostatic chuck, the heating layer and the base, and the lifting channel is provided with lifting pins for lifting the substrate.

[0021] The third aspect of the present invention provides a plasma processing device, which includes: a reaction chamber; the bottom of the reaction chamber is provided with the above-mentioned lower electrode assembly for carrying a substrate to be processed; a gas supply assembly arranged opposite to the lower electrode assembly; a reaction gas is introduced into the reaction chamber through the gas supply assembly to perform plasma etching on the substrate; a radio frequency source is electrically connected to the lower electrode assembly and is used to excite the reaction gas to form plasma.

[0022] Compared with the prior art, the present invention has at least the following advantages:

[0023] The gas guide cover provided by the present invention is easy to machine. By machining a plurality of gas guide channels with controllable spacing and diameter on the gas guide cover, the heat-conducting gas is evenly diffused and distributed on the surface of the electrostatic chuck, thereby ensuring the temperature uniformity of the substrate W on the electrostatic chuck.

[0024] On the one hand, the present invention covers the vent holes of the electrostatic chuck with a gas guide cover plate extending longitudinally and transversely along the gas guide groove, so that the width above the vent hole is reduced from the distance between the two inner sides of the gas guide groove to the distance between the inner side of the gas guide groove and the outer side of the gas guide cover plate. Under a certain radio frequency power, the width above the vent hole exposed to the helium environment is significantly reduced compared to the width above the existing vent hole exposed to the helium environment, thereby reducing the voltage distributed in the space above the vent hole, thereby reducing the risk of discharge, and avoiding the problem of damage to the substrate caused by discharge due to the dissociation or breakdown of the heat-conducting gas at the vent hole caused by excessive voltage.

[0025] On the other hand, by setting a plurality of gas-conducting channels on the gas-conducting cover plate, and the diameter of the gas-conducting channels is smaller than the diameter of the vent holes, the vent holes with larger diameters that were originally exposed to the helium environment are decomposed into gas-conducting channels with smaller diameters, thereby reducing the probability of discharge at the vent holes, and further avoiding the phenomenon of discharge caused by the dissociation or breakdown of the heat-conducting gas. Furthermore, the gas-conducting channels can be arranged at intervals along the circumference of the gas-conducting cover plate, or symmetrically arranged on the two opposite side walls of the gas-conducting cover plate to form gas flow channels that cross the gas-conducting cover plate, thereby improving the diffusion uniformity and flow efficiency of the heat-conducting gas, thereby improving the heat-conducting efficiency of the heat-conducting gas, and ensuring the temperature uniformity of the substrate.

[0026] In summary, an electrostatic chuck, a lower electrode assembly and a plasma processing device of the present invention, by covering the air holes of the electrostatic chuck with an air guide cover extending laterally and longitudinally along the air guide groove, and a plurality of air guide holes are provided on the air guide cover, thereby ensuring that the heat-conducting gas is evenly diffused on the surface of the electrostatic chuck, thereby ensuring the temperature uniformity of the substrate on the electrostatic chuck, and avoiding the problem of damage to the substrate caused by discharge due to the dissociation or breakdown of the heat-conducting gas at the air holes caused by excessive voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a cross-sectional schematic diagram of a lower electrode assembly in the prior art;

[0028] Figure 2 is a top view of an embodiment of an electrostatic chuck of the present invention;

[0029] Figure 3 is a cross-sectional schematic diagram of an embodiment of an electrostatic chuck in the present invention;

[0030] Figure 4 is a three-dimensional schematic diagram of an embodiment of an electrostatic chuck in the present invention;

[0031] Figure 5 A partially enlarged top view of an embodiment of an electrostatic chuck of the present invention;

[0032] Figure 6 is a cross-sectional schematic diagram of another embodiment of an electrostatic chuck in the present invention;

[0033] Figure 7 is a cross-sectional schematic diagram of the lower electrode assembly in the present invention;

[0034] Figure 8 Schematic diagram of a plasma processing device according to the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that, in this article, the terms "include", "comprises", "has" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "includes..." or "comprising..." do not exclude the existence of other elements in the process, method, article or terminal device including the elements.

[0037] It should be noted that the drawings are all in very simplified form and use inaccurate ratios, and are only used to conveniently and clearly assist in explaining an embodiment of the present invention.

[0038] In the prior art, Figure 1 As shown, the surface of the electrostatic chuck 10 is provided with a helium tank 12, and a plurality of pores 11 are provided in the helium tank 12 for transmitting helium to the surface of the electrostatic chuck 10. During the reaction process, the surface of the electrostatic chuck 10 will be directly exposed to the action of the radio frequency power. Since the space corresponding to the position where the pores 11 are provided in the helium tank 12 is relatively large, the voltage distributed in the space is relatively large, and the helium at the pores 11 will be more easily dissociated or broken down under the action of the radio frequency power to form discharge, causing certain damage to the substrate, and also generating some impurity particles, resulting in substrate contamination.

[0039] In view of the above-mentioned defects, the idea adopted by the present invention is to reduce the space that can accommodate helium at the position of the helium slot 12 corresponding to the air hole 11, that is, to reduce the volume occupied by the helium between the side walls of the helium slot 12, thereby increasing the capacitance of the position of the air hole 11 corresponding to the helium slot 12, so as to reduce the voltage obtained at this position, thereby reducing the discharge probability of the air hole 11, and avoiding the problem of helium at the air hole 11 on the electrostatic chuck 10 being dissociated or broken down to form discharge.

[0040] Based on the above invention ideas, an embodiment of the present invention provides an electrostatic chuck 100 for carrying a substrate in a plasma processing device, such as Figure 2 and Figure 3As shown, the electrostatic chuck 100 includes an insulating layer 101, whose upper surface is opposite to the lower surface of the substrate W and is provided with an electrode 111 inside; the electrode 111 is connected to a DC power supply, and by applying the DC power supply, an electrostatic force is generated between the substrate W and the insulating layer 101, so that the substrate W is firmly adsorbed on the electrostatic chuck 100; the upper surface of the insulating layer 101 is provided with a plurality of mutually connected air guide grooves 102, and the air guide grooves 102 are provided with a plurality of air vents 103 penetrating the insulating layer 101, which are used to provide air to the electrostatic chuck 100 and the substrate to be processed. W; an air-conducting cover plate 104, which is arranged in the air-conducting groove 102 and is located above the air vent 103, and the air-conducting cover plate 104 has a lateral and longitudinal extension in the air-conducting groove 102, so that the air-conducting cover plate 104 can cover the corresponding air vent 103, and an air-conducting channel 141 is arranged in the air-conducting cover plate 104, and the air-conducting channel 141 connects the air vent 103 with the air-conducting groove 102, so that the heat-conducting gas is transmitted to between the insulating layer 101 and the substrate W through the air vent 103 and the air-conducting channel 141 in sequence.

[0041] In this embodiment, by providing an air guide cover plate 104 extending longitudinally and transversely along the air guide groove 102 above the air vent 103, the space for accommodating the heat-conducting gas at the position of the air guide groove 102 corresponding to the air vent 103 is reduced, and replaced by a heat-conducting cover plate 104 with a larger dielectric constant. Specifically, after the air guide cover plate 104 is added to the air guide groove 102, the flow width of the heat-conducting gas above the air vent 103 is reduced from the distance between the two inner side surfaces of the air guide groove 102 to the distance between the inner side surface of the air guide groove 102 and the outer side surface of the air guide cover plate 104. Under a certain RF power, the width of the air hole 103 with the air-conducting cover plate 104 exposed to the heat-conducting gas environment is significantly reduced compared to the width of the existing air hole 11 exposed to the heat-conducting gas environment, thereby reducing the voltage distributed in the space above the air hole 103, thereby reducing the risk of discharge and avoiding the problem of damage to the substrate caused by discharge due to the dissociation or breakdown of the heat-conducting gas at the air hole 103 caused by excessive voltage.

[0042] Among them, Figure 2As shown, in this embodiment, the gas guide grooves 102 include a plurality of annular gas guide grooves 121 arranged around the electrostatic chuck 100, a plurality of linear gas guide grooves 122 arranged at intervals along the radial direction of the electrostatic chuck 100, and a circular gas guide groove 123 arranged at the center of the electrostatic chuck 100; each of the linear gas guide grooves 122 connects each annular gas guide groove 121 with the circular gas guide groove 123, that is, the annular gas guide groove 121 connects each linear gas guide groove 122 with the circular gas guide groove 123, and finally forms mutually connected gas guide grooves 102 on the electrostatic chuck 100, so that the heat-conducting gas can be uniformly diffused on the electrostatic chuck 100 along the gas guide grooves 102, which is beneficial to the uniformity of the substrate temperature. In this embodiment, the gas guide holes 103 are arranged in each linear gas guide groove 122 and the circular gas guide groove 123. In other embodiments, the gas guide holes 103 can be arranged in the annular gas guide groove 121 according to the layout requirements.

[0043] Further, if Figure 2 and Figure 3 As shown, the direction of the gas guide channel 141 is arranged perpendicularly to the direction of the vent hole 103. After the heat-conducting gas is transmitted to the gas guide cover plate 104 along the vent hole 103, it continues to flow along the gas guide channel 141 in the gas guide cover plate 104. Since the gas guide channel 141 is arranged perpendicularly to the vent hole 103, the flow direction of the heat-conducting gas changes from vertical to horizontal, making it easier for the heat-conducting gas to flow and diffuse along the direction of the gas guide groove 102, thereby ensuring the flow rate of the heat-conducting gas and thereby improving the uniformity of the substrate temperature.

[0044] In order to ensure that there is a diffusion gap for the heat-conducting gas between the substrate W and the electrostatic chuck 100 and to avoid excessive temperature difference on the back side of the substrate W, as shown in FIG. Figure 3 The upper surface of the insulating layer 101 includes a plurality of protrusions 112, which are arranged between adjacent linear gas guide grooves 122, and are used to support the substrate W, so that a diffusion gap for heat-conducting gas is formed between the lower surface of the substrate W and the upper surface of the insulating layer 101, thereby improving the uniformity of distribution of heat-conducting gas on the lower surface of the substrate W. If the protrusions 112 are not provided, since the electrostatic chuck 100 adsorbs the substrate W on the upper surface of the electrostatic chuck 100 by electrostatic force, the lower surface of the substrate W will be in direct contact with the upper surface of the insulating layer 101, that is, the lower surface of the substrate W is closely attached to the upper surface of the insulating layer 101, so that the heat-conducting gas can only flow in the gas guide grooves 102, thereby reducing the heat transfer efficiency between the substrate and the heat-conducting gas, thereby causing a decrease in the uniformity of the substrate temperature.

[0045] Further, if Figure 3As shown, the top height of the air guide cover plate 104 is located between the bottom surface of the air guide groove 102 and the upper surface of the insulating layer 101, so as to prevent the air guide cover plate 104 from being too high and lifting the substrate W, thereby causing the electrostatic chuck 100 to be unable to adsorb the substrate W through electrostatic force. It should be noted that if the upper surface of the insulating layer 101 is provided with a protrusion 112, the top height of the air guide cover plate 104 is not higher than the height of the protrusion 112.

[0046] In order to prevent the air guide cover plate 104 from being completely blocked in the air guide groove 102, Figure 4 and Figure 5 As shown, the width of the position where the air vent 103 is provided in the air guide groove 102 is greater than the width of the other positions of the air guide groove 102, and there is a gap between the outer side surface of the air guide cover plate 104 and the inner side surface of the air guide groove 102, so that when the heat-conducting gas flows along the air guide groove 102 to the air guide cover plate 104, the heat-conducting gas can flow through the gap; at the same time, the widened part of the air guide groove 102 also increases the diffusion space of the heat-conducting gas, so that the heat-conducting gas can be initially diffused in the diffusion space after flowing out of the air guide channel 141, and then flow along the direction of the air guide groove 102.

[0047] Further, if Figure 2 and Figure 3 As shown, the electrostatic chuck 100 also includes an annular boss 105 extending horizontally upward along the circumferential edge of the upper surface of the insulating layer 101, and the upper surface of the annular boss 105 is in contact with the lower surface of the substrate W, forming a closed area between the lower surface of the substrate W and the upper surface of the insulating layer 101 of the electrostatic chuck 100, effectively preventing the escape of the heat-conducting gas diffused between the insulating layer 101 and the substrate W; at the same time, if the protrusion 112 is not provided on the upper surface of the insulating layer 101, the closed area formed by the circumferential edge of the substrate W overlapping the annular boss 105 can also be used as a diffusion gap to allow the heat-conducting gas to flow and diffuse in the area, thereby improving the distribution uniformity of the heat-conducting gas on the lower surface of the substrate W.

[0048] like Figure 2 to Figure 5 As shown, the air guide channel 141 is a plurality of air guide holes arranged at intervals in the horizontal direction of the air guide cover plate 104, and each of the air guide holes is connected to the vent hole 103, so that the heat transfer gas diffuses more evenly. Figure 4 and Figure 5As shown, the air guide cover plate 104 covers two air vents 103, and eight air guide holes 142 are arranged at intervals in the horizontal circumference of the air guide cover plate 104, and each air vent 103 is connected with four air guide holes 142 to form four air guide channels, so that the heat-conducting gas can flow out of the air guide cover plate 104 along the air guide holes 142 after flowing from the air vent 103 to the air guide cover plate 104; at the same time, the two air vents 103 located in the same air guide cover plate 104 are connected through an air guide hole 142 to improve the flow efficiency of the heat-conducting gas. Of course, in other embodiments, the air guide hole 142 can also be a through hole arranged across the air guide cover plate 104, and the air guide hole 142 is connected with the air vent 103 to increase the number of air guide channels, that is, to increase the flow channel of the heat-conducting gas, and improve the flow uniformity and flow efficiency of the heat-conducting gas.

[0049] Further, if Figure 2 to Figure 5 As shown, the diameter of the gas guide channel 141 is smaller than the diameter of the vent hole 103. With this arrangement, the original heat-conducting gas flowing through the vent hole 103 with a larger diameter is decomposed into gas guide channels 141 with a smaller diameter, which can reduce the probability of discharge at the vent hole 103 and further avoid the phenomenon of discharge due to dissociation or breakdown of the heat-conducting gas.

[0050] Taking into account the controllability of actual mechanical processing and the particularity of the plasma treatment process, the material of the insulating layer 101 and the air guide cover plate 104 provided in this embodiment is preferably ceramic, so that the diameter size of the air guide channel 141 on the air guide cover plate 104 can be more easily controlled while meeting the plasma treatment process.

[0051] In another embodiment, if Figure 6 As shown, a hollow cavity is formed between the lower side of the air guide cover plate 204 and the air guide groove 102, the hollow cavity is connected to the vent hole 103, and the side wall of the air guide cover plate 204 is provided with at least one air guide port 242 to form an air guide channel 241. Specifically, in this embodiment, the air guide cover plate 204 includes a top wall and four side walls, the four side walls are arranged in the circumference of the lower surface of the top wall, surrounding the hollow cavity; the hollow cavity is connected to the vent hole 103, and at least one air guide port 242 is provided on each side wall, the air guide port 242 is connected to the hollow cavity to form the air guide channel 241, when the heat-conducting gas flows along the vent hole 103 to the hollow cavity, it is initially diffused in the hollow cavity to improve the uniformity of the flow rate of the heat-conducting gas flowing out from different air guide ports 242, thereby ensuring the diffusion uniformity of the heat-conducting gas.

[0052] As an optional embodiment, Figure 6As shown, the air guide cover plate 204 is provided with at least one pair of air guide ports 242, and each pair of air guide ports 242 is symmetrically arranged on opposite side walls of the air guide cover plate 204, forming an air guide channel 241 that crosses the air guide cover plate 204. Further, if the opening size of the air guide ports 242 is equal to the area of ​​the side wall on one side, the air guide cover plate 204 is composed of a top wall and two oppositely arranged side walls, and the symmetrically arranged air guide ports 242 are opened on two side walls along the gas flow direction of the air guide groove 102. By increasing the opening area of ​​the air guide ports 242, it is more conducive to the diffusion of the heat-conducting gas along the gas flow direction of the air guide groove 102, which speeds up the flow rate of the heat-conducting gas and thus improves the heat conduction efficiency.

[0053] like Figure 7 As shown, the present invention also provides a lower electrode assembly 300, which is arranged in the reaction chamber of the plasma processing device, and includes the above-mentioned electrostatic chuck 100, and a base 301 for supporting the electrostatic chuck 100 is arranged below the electrostatic chuck 100; a heating layer 302 is arranged between the base 301 and the electrostatic chuck 100, and a plurality of heaters 321 are arranged in the heating layer 302 for heating the substrate W; an adhesive layer (not shown) is also arranged below the heating layer 302, and the electrostatic chuck 100 and the heating layer 302 are bonded to the base 301 through the adhesive layer; a ventilation line 304 is arranged in the base 301, and the ventilation line 304 passes through the base 301 and the heating layer 302 in sequence and is connected to the ventilation hole 103 for transmitting heat-conducting gas. Because the ventilation hole 103 of the electrostatic chuck 100 in this embodiment is covered with a gas guide cover plate 104 provided with a gas guide channel 141. The lower electrode assembly provided in this embodiment is suitable for any plasma processing device that needs to control the temperature of the processed substrate, such as a capacitively coupled plasma processing device and an inductively coupled plasma processing device. In this embodiment, by setting a gas guide cover plate 104 on the vent hole 103, the gas flow interval between the gas guide grooves 102 corresponding to the vent hole 103 is reduced, thereby reducing the risk of discharge; at the same time, a plurality of gas guide channels 141 are set on the gas guide cover plate 104, so that the heat-conducting gas can flow evenly into the gas guide groove 102 through the gas guide channel 141, thereby achieving uniform diffusion and distribution of the heat-conducting gas on the surface of the electrostatic chuck 100, thereby improving the temperature uniformity of the substrate W.

[0054] Further, if Figure 7 As shown, a cooling channel 303 is further provided in the base 301 . The cooling channel 303 is provided along the circumference of the base 301 , and the cooling channel 303 is connected to a cooling liquid source. The cooling liquid is passed into the cooling channel 303 to cool the base 301 .

[0055] As an optional embodiment, the gas source connected to the ventilation pipe 304 is helium; the helium is transmitted to the space between the substrate W and the insulating layer 101 through the ventilation pipe 304, the ventilation hole 103 and the gas guide cover 104 in sequence. The guiding effect of the gas guide cover 104 on the helium is more conducive to achieving uniform diffusion distribution of the helium on the surface of the electrostatic chuck 100, thereby ensuring the temperature uniformity of the substrate W on the electrostatic chuck 100, so as to promote the uniformity of substrate etching. Specifically, when the substrate W needs to be cooled, the coolant is introduced into the cooling channel 303 of the base 301 to cool the base 301. At this time, the temperature of the insulating layer 101 decreases due to the influence of the cooled base 301. Helium, as a heat-conducting gas, can transfer the excess heat of the substrate W to the insulating layer 101. When the substrate W needs to be heated, the heating layer 302 heats the insulating layer 301. Helium, as a heat-conducting gas, can transfer the excess heat of the insulating layer 101 to the substrate W to ensure the temperature uniformity of the substrate W. The heat conduction efficiency is adjusted by adjusting the helium pressure. When the helium pressure is high, the heat conduction efficiency is high; when the helium pressure is low, the heat conduction efficiency is low.

[0056] like Figure 7 As shown, the base 301 further includes a lifting channel 305 that runs through the electrostatic chuck 100, the heating layer 302 and the base 301. The lifting channel 305 is provided with lifting pins (not shown) for lifting the substrate W. The lifting channel 305 and the cooling channel 303, the heater 321 and the electrode 111 are all staggered to avoid affecting the normal operation of the cooling channel 303, the heater 321 and the electrode 111.

[0057] The present invention also provides a plasma processing device, such as Figure 8 As shown, it comprises: a reaction chamber 401; the bottom of the reaction chamber 401 is provided with the above-mentioned lower electrode assembly 300 for carrying the substrate W to be processed; a gas supply assembly 402 arranged opposite to the lower electrode assembly 300; a reaction gas is introduced into the reaction chamber 401 through the gas supply assembly 402 to perform plasma etching on the substrate W; a radio frequency source 403, electrically connected to the lower electrode assembly 300, for exciting the reaction gas to form plasma. For the same reason, the plasma processing device provided by the present invention can avoid the problem of damage to the substrate caused by the discharge phenomenon caused by the dissociation of the heat-conducting gas at the vent of the electrostatic chuck.

[0058] The gas guide cover plate 104 provided by the present invention is easy to machine. By machining a plurality of gas guide channels 141 with controllable spacing and diameter on the gas guide cover plate 104, the heat-conducting gas is evenly diffused and distributed on the surface of the electrostatic chuck 100, thereby ensuring the temperature uniformity of the substrate W on the electrostatic chuck 100.

[0059] On the one hand, the present invention covers the vent 103 of the electrostatic chuck 100 with a gas guide cover 104 extending longitudinally and transversely along the gas guide groove 102, so that the width above the vent 103 is reduced from the distance between the two inner sides of the gas guide groove 102 to the distance between the inner side of the gas guide groove 102 and the outer side of the gas guide cover 104. Under a certain radio frequency power, the width above the vent 103 with the gas guide cover 104 exposed to the helium environment is significantly reduced compared to the width above the existing gas hole 11 exposed to the helium environment, thereby reducing the voltage distributed in the space above the vent 103, thereby reducing the risk of discharge, and avoiding the problem of damage to the substrate caused by discharge due to the dissociation or breakdown of the heat-conducting gas at the vent 103 caused by excessive voltage.

[0060] On the other hand, by setting a plurality of gas-conducting channels 141 on the gas-conducting cover plate 104, and the diameter of the gas-conducting channels 141 is smaller than the diameter of the vent hole 103, the vent hole 103 with a larger diameter originally exposed to the helium environment is decomposed into gas-conducting channels 141 with a smaller diameter, thereby reducing the probability of discharge at the vent hole 103, and further avoiding the phenomenon of discharge caused by the dissociation or breakdown of the heat-conducting gas. Furthermore, the gas-conducting channels 141 can be arranged at intervals along the circumference of the gas-conducting cover plate 104, or symmetrically arranged on two opposite side walls of the gas-conducting cover plate 104 to form a gas flow channel that crosses the gas-conducting cover plate, thereby improving the diffusion uniformity and flow efficiency of the heat-conducting gas, thereby improving the heat-conducting efficiency of the heat-conducting gas, and ensuring the temperature uniformity of the substrate W.

[0061] In summary, an electrostatic chuck, a lower electrode assembly and a plasma processing device of the present invention, by covering the air holes of the electrostatic chuck with an air guide cover extending laterally and longitudinally along the air guide groove, and a plurality of air guide holes are provided on the air guide cover, thereby ensuring that the heat-conducting gas is evenly diffused on the surface of the electrostatic chuck, thereby ensuring the temperature uniformity of the substrate on the electrostatic chuck, and avoiding the problem of damage to the substrate caused by discharge due to the dissociation or breakdown of the heat-conducting gas at the air holes caused by excessive voltage.

[0062] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. An electrostatic chuck for carrying a substrate in a plasma processing device, It is characterized in that include: An insulating layer, the upper surface of which is opposite to the lower surface of the substrate, and an electrode is provided inside the insulating layer; A plurality of mutually connected air guide grooves, which are arranged on the upper surface of the insulating layer; The air guide groove is provided with a plurality of air vents penetrating the insulating layer; An air guide cover plate, which is arranged in the air guide groove and located above the air vents, covering the corresponding air vents; An air guide channel is provided in the air guide cover plate, and the air guide channel connects the air vents and the air guide grooves, so that the heat-conducting gas is transmitted to between the insulating layer and the substrate through the air vents and the air guide channel in sequence.

2. The electrostatic chuck according to claim 1, It is characterized in that The direction of the air guide channel is perpendicular to the direction of the vent hole.

3. The electrostatic chuck according to claim 1, It is characterized in that The upper surface of the insulating layer includes a plurality of protrusions, and the protrusions are used to support the substrate so that a diffusion gap for heat-conducting gas is formed between the lower surface of the substrate and the upper surface of the insulating layer.

4. The electrostatic chuck according to claim 1, It is characterized in that The top height of the air guide cover plate is located between the bottom surface of the air guide groove and the upper surface of the insulating layer.

5. The electrostatic chuck according to claim 1, It is characterized in that The width of the position where the air guide groove is provided with the air vent is greater than the width of the remaining positions of the air guide groove, and there is a gap between the outer side surface of the air guide cover plate and the inner side surface of the air guide groove.

6. The electrostatic chuck according to claim 1, It is characterized in that It also includes an annular boss extending horizontally upward along the circumferential edge of the upper surface of the insulating layer, which is used to prevent the escape of heat-conducting gas between the insulating layer and the substrate.

7. The electrostatic chuck according to claim 1, It is characterized in that The air guide channel is a plurality of air guide holes arranged at intervals in the horizontal direction of the air guide cover plate, and each of the air guide holes is connected to the vent hole, so that the heat-conducting gas is evenly diffused.

8. The electrostatic chuck according to claim 7, It is characterized in that The diameter of the air guiding channel is smaller than the diameter of the vent hole.

9. The electrostatic chuck according to claim 1, It is characterized in that A hollow cavity is formed between the air guide cover plate and the lower surface of the air guide groove, the hollow cavity is communicated with the air vent, and the side wall of the air guide cover plate is provided with at least one air guide port to form an air guide channel.

10. The electrostatic chuck according to claim 9, It is characterized in that At least one pair of air guide ports is disposed on the air guide cover plate, and each pair of air guide ports is symmetrically disposed on opposite side walls of the air guide cover plate to form an air guide channel that crosses the air guide cover plate.

11. The electrostatic chuck according to claim 1, It is characterized in that The insulating layer and the air guide cover plate are both made of ceramic.

12. A lower electrode assembly, It is characterized in that include: The electrostatic chuck according to any one of claims 1 to 11, wherein a base for supporting the electrostatic chuck is provided below the electrostatic chuck; A heating layer is provided between the base and the electrostatic chuck, and a plurality of heaters are provided in the heating layer for heating the substrate; A ventilation pipeline is arranged in the base, and the ventilation pipeline passes through the base and the heating layer in sequence and is connected with the ventilation hole for transmitting heat-conducting gas.

13. The lower electrode assembly according to claim 12, It is characterized in that The base also includes a cooling channel for passing cooling liquid to cool the base.

14. The lower electrode assembly according to claim 12, It is characterized in that It also includes a lifting channel that runs through the electrostatic chuck, the heating layer and the base, and the lifting channel is provided with lifting pins for lifting the substrate.

15. A plasma processing device, It is characterized in that include: Reaction chamber; The bottom of the reaction chamber is provided with a lower electrode assembly as claimed in any one of claims 12 to 14 for carrying a substrate to be processed; A gas supply assembly disposed opposite to the lower electrode assembly; Introducing reaction gas into the reaction chamber through the gas supply assembly to perform plasma etching on the substrate; A radio frequency source is electrically connected to the lower electrode assembly and is used to excite the reaction gas to form plasma.

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