Electrostatic chuck and semiconductor processing apparatus

Abstract

This invention provides an electrostatic chuck and semiconductor processing equipment. The electrostatic chuck includes an annular air passage, a main air passage group, and a secondary air passage group. The annular air passage is located near the edge of the upper surface of the chuck body, defining a heat exchange area within it. The main air passage group surrounds a central air inlet, and the secondary air passage group surrounds the main air passage group. The main air passage group is connected to both the central air inlet and the secondary air passage group, and is configured to increase the speed at which the back-blown gas flowing from the central air inlet is delivered to the secondary air passage group. The secondary air passage group is connected to both the main air passage group and the annular air passage, and is configured to ensure uniform distribution of the back-blown gas at different locations within the heat exchange area. The electrostatic chuck and semiconductor processing equipment provided by this invention can effectively shorten the back-blown gas passage time while ensuring the stability and uniformity of the back-blown gas pressure, thereby increasing equipment productivity.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more specifically, to an electrostatic chuck and semiconductor processing equipment. Background Technology

[0002] An electrostatic chuck (ESC) is used to hold a wafer by electrostatic attraction, preventing the wafer from moving or misaligning during the process. During the process, a back-blown gas at a certain pressure is introduced into the gap between the ESC and the wafer to improve the heat transfer capability of the ESC to the wafer, avoiding vacuum insulation and thus improving the ESC's ability to control the wafer temperature. In addition, the ESC can also provide radio frequency bias voltage to the wafer.

[0003] Electrostatic chucks are typically placed in a vacuum chamber. Taking a Physical Vapor Deposition (PVD) machine as an example, when the wafer is transferred to the vacuum chamber of the PVD machine and placed on the electrostatic chuck, the vacuum chamber is in a background vacuum state (the background vacuum level is typically around 10). -8 Torr or 10 -9 (On the order of Torr). At this point, the wafer and the electrostatic chuck are in a vacuum-insulated state. The electrostatic chuck cannot control the temperature of the wafer. It is necessary to introduce back-blown gas into the gap between the two and maintain a certain pressure (e.g., 1-20 Torr). The back-blown gas can transfer heat between the electrostatic chuck and the wafer to achieve the temperature control capability of the electrostatic chuck.

[0004] Electrostatic chucks can be divided into two types: Coulomb type and Johnsen-Rahbek effect (JR type). The Coulomb type electrostatic chuck works by using the electrostatic attraction between the electrodes and the wafer to attract the wafer, while the JR type electrostatic chuck works by using the electrostatic attraction between the upper surface of the chuck and the wafer. To improve heat transfer efficiency, air channels are usually provided on the upper surface of the electrostatic chuck to help backblown gas diffuse to different locations on the wafer. However, because the electrodes in the Coulomb type electrostatic chuck are close to the wafer, the dielectric layer above the electrodes is thin, making it impossible to create these air channels. In contrast, the electrodes in the JR type electrostatic chuck are farther from the wafer, resulting in a thicker dielectric layer above the electrodes, allowing for the creation of air channels.

[0005] However, for JR-type electrostatic chucks, the existing air passage structure requires back-blown gas to be introduced for a relatively long time (more than 100 seconds) in order to ensure that the stability and uniformity of the back-blown gas pressure meet the process requirements before the PVD process can begin. The PVD process time is generally only in the range of 20-100 seconds, resulting in low equipment capacity and making it unsuitable for industrial production. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes an electrostatic chuck and semiconductor processing equipment, which can effectively shorten the back-blowing gas ventilation time while ensuring that the back-blowing gas pressure meets the requirements of stability and uniformity, thereby improving the equipment's production capacity.

[0007] To achieve the purpose of this invention, an electrostatic chuck is provided for use in semiconductor processing equipment. The chuck body includes a chuck body, and the upper surface of the chuck body is provided with a bump structure, a central air inlet, and an air passage structure. The bump structure is located in the non-air passage area of ​​the upper surface of the chuck body and is used to support the wafer. The bearing surface of the bump structure has a preset distance from the upper surface of the chuck body.

[0008] The air passage structure includes an annular air passage, a main air passage group, and a secondary air passage group. The annular air passage is located at the edge of the upper surface of the chuck body to define a heat exchange area inside it. The main air passage group and the secondary air passage group are both distributed in the heat exchange area, and the main air passage group surrounds the central air inlet, while the secondary air passage group surrounds the main air passage group.

[0009] The main air duct assembly is connected to the central air inlet and the secondary air duct assembly respectively, and is configured to increase the speed at which the back-blown gas flowing out of the central air inlet is delivered to the secondary air duct assembly.

[0010] The secondary air duct group is connected to the main air duct group and the annular air duct respectively, and is configured to enable the back-blown gas to be evenly distributed at different positions in the heat exchange area.

[0011] Optionally, the projected area of ​​the main air passage assembly on the upper surface of the chuck body is less than or equal to 50% of the area of ​​a designated region on the upper surface of the chuck body, where the designated region is the area of ​​a circle with the center of the upper surface as its center and a designated diameter.

[0012] Optionally, the specified diameter is 50 mm.

[0013] Optionally, the main air duct group includes multiple main air ducts evenly distributed circumferentially around the central air inlet. Each main air duct is arranged radially along the central air inlet, and the air inlet end of each main air duct is connected to the central air inlet, while the air outlet end of each main air duct is connected to the secondary air duct group.

[0014] Optionally, the width of the main airway is greater than or equal to 0.5 mm and less than or equal to 3 mm; the depth of the main airway is greater than or equal to 0.1 mm and less than or equal to 0.4 mm; and the number of main airways is greater than or equal to 9 and less than or equal to 20.

[0015] Optionally, the secondary airway group includes a primary sub-airway group, which includes multiple secondary airways. The outlet of each primary airway is connected to the inlet of at least one secondary airway, and the multiple secondary airways connected to the same primary airway extend from the outlet of that primary airway in different directions away from the central inlet; or,

[0016] The secondary airway group includes multiple levels of sub-airway groups that are sequentially arranged in a direction away from the central air inlet. Each level of the sub-airway group includes multiple secondary airways. The outlet end of each main airway is connected to the inlet end of at least one secondary airway in the adjacent first-level sub-airway group. Multiple secondary airways connected to the same main airway extend from the outlet end of the main airway in different directions away from the central air inlet. The outlet end of each secondary airway in the upstream level is connected to the inlet end of at least one secondary airway in the adjacent downstream level. Multiple secondary airways in the downstream level connected to the same primary airway in the upstream level extend from the outlet end of the secondary airway in the upstream level in different directions away from the central air inlet.

[0017] Optionally, the width of the secondary airway is greater than or equal to 0.5 mm and less than or equal to 3 mm; the depth of the secondary airway is greater than or equal to 0.1 mm and less than or equal to 0.4 mm; and the number of secondary airways is greater than or equal to 9 and less than or equal to 100.

[0018] Optionally, the secondary airway group includes two levels of sub-airway groups, namely a first-level airway group and a second-level airway group. The first-level airway group includes multiple primary airways. The outlet of each primary airway is connected to the inlet of three of the primary airways. Among the three primary airways connected to the same primary airway, the middle primary airway is coaxial with the primary airway, and the two primary airways on both sides are symmetrically distributed with respect to the middle primary airway. Furthermore, the outlets of any two adjacent primary airways connected to different primary airways converge to form a first common outlet.

[0019] The second-level airway group includes multiple secondary airways. Among the three primary airways connected to the same primary airway, the outlet of the middle primary airway is connected to the inlet of two of the secondary airways. Each first common outlet is connected to the inlet of two of the secondary airways. Furthermore, any two adjacent secondary airways connected to the outlet of the primary airway and the outlet of the secondary airway connected to the first common outlet converge to form a second common outlet, which is connected to the annular airway.

[0020] Optionally, the secondary airway group further includes multiple transition airways, with the inlet end of each transition airway correspondingly connected to each of the second common air outlet ends, and the outlet end of each transition airway connected to the annular airway.

[0021] Optionally, the diameter of the annular centerline of the annular airway is greater than or equal to 270 mm and less than or equal to 290 mm; the radial width of the annular airway is greater than or equal to 0.5 mm and less than or equal to 3 mm; and the depth of the annular airway is greater than or equal to 0.1 mm and less than or equal to 0.4 mm.

[0022] Optionally, the bump structure includes a plurality of bumps evenly distributed in the non-air passage area, wherein the total orthographic projection area of ​​the plurality of bumps on the upper surface of the chuck body accounts for a proportion of greater than or equal to 2% and less than or equal to 10% of the upper surface area of ​​the chuck body.

[0023] Optionally, the preset spacing is greater than or equal to 2μm and less than or equal to 10μm.

[0024] As another technical solution, the present invention also provides a semiconductor processing apparatus, including a process chamber and an electrostatic chuck disposed in the process chamber, wherein the electrostatic chuck is the electrostatic chuck provided by the present invention.

[0025] The present invention has the following beneficial effects:

[0026] The electrostatic chuck provided by this invention has an air passage structure including an annular air passage, a main air passage group, and a secondary air passage group. The annular air passage is located at the edge near the upper surface of the chuck body, defining a heat exchange area inside it to ensure that the air pressure in this area is not affected by the chamber pressure, thus ensuring air pressure stability and enabling the back-blown gas to perform normal heat exchange. The main air passage group and the secondary air passage group are both distributed in this heat exchange area. The main air passage group surrounds the central air inlet and is connected to both the central air inlet and the secondary air passage group. It is configured to increase the speed at which the back-blown gas flowing out of the central air inlet is delivered to the secondary air passage group, thereby ensuring that the back-blown gas can quickly diffuse from the central air inlet to the surrounding areas. The secondary air passage group surrounds the main air passage group and is connected to both the main air passage group and the annular air passage group. It is configured to ensure that the back-blown gas is evenly distributed at different positions in the heat exchange area. The main air duct assembly mentioned above plays a major role in enabling the back-blown air pressure to quickly reach the stability requirements, while the secondary air duct assembly plays a major role in enabling the back-blown gas to quickly reach the uniformity requirements. Therefore, by combining the main air duct assembly and the secondary air duct assembly, the back-blown gas ventilation time can be effectively shortened while ensuring that the back-blown air pressure reaches the stability and uniformity requirements, thereby improving the equipment's production capacity.

[0027] The semiconductor processing equipment provided by this invention, by employing the electrostatic chuck provided by this invention, can effectively shorten the back-blowing gas passage time while ensuring that the back-blowing gas pressure meets the requirements of stability and uniformity, thereby improving the equipment's production capacity. Attached Figure Description

[0028] Figure 1 This is a side cross-sectional view of the electrostatic chuck provided in the first embodiment of the present invention;

[0029] Figure 2 A top view of the air passage structure of the electrostatic chuck provided in the first embodiment of the present invention;

[0030] Figure 3 Another top view of the air passage structure of the electrostatic chuck provided in the first embodiment of the present invention;

[0031] Figure 4 This is a top view of the air passage structure of the electrostatic chuck provided in the second embodiment of the present invention;

[0032] Figure 5 This is an overall top view of the electrostatic chuck provided in the third embodiment of the present invention;

[0033] Figure 6 for Figure 5 A partial top view of the electrostatic chuck;

[0034] Figure 7This is a comparison graph of the average air pressure versus time curves of the electrostatic chuck used in the third embodiment of the present invention and the electrostatic chuck of the prior art.

[0035] Figure 8 This is a comparison graph showing the relationship between air pressure and wafer position between the electrostatic chuck used in the third embodiment of the present invention and the electrostatic chuck of the prior art. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solution of the present invention, the electrostatic chuck and semiconductor processing equipment provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0037] First Embodiment

[0038] Please see Figure 1 This embodiment provides an electrostatic chuck 1, which includes a chuck body 11. Electrodes 12 are disposed within the chuck body 11. These electrodes 12 are typically electrically connected to a DC power supply to provide power for adsorbing wafers. Generally, the portion of the chuck body 11 above the electrodes 12 is a dielectric layer, and the portion below the electrodes 12 is a base. Both the dielectric layer and the base are made of ceramic material, and the electrodes 12 can be embedded within the ceramic material by sintering.

[0039] The electrostatic chuck 1 provided in this embodiment is a Johnsen-Rahbek effect (JR type) electrostatic chuck. Its working principle is to use the electrostatic attraction generated between the upper surface 111 of the chuck body 11 and the wafer 2 to attract the wafer 2. Based on this, in this embodiment, the upper surface 111 of the chuck body 11 is provided with a bump structure, a central air inlet, and an air passage structure. The bump structure includes a plurality of bumps 13 evenly distributed in the non-air passage area (the area other than the central air inlet and air passage structure). The bearing surface formed by the plurality of bumps 13 is used to support the wafer 2, and there is a preset distance (i.e., the height of the bumps 13) between the bearing surface and the upper surface 111 of the chuck body 11. The preset distance is set to generate a sufficiently large electrostatic attraction between the upper surface 111 of the chuck body 11 and the wafer 2 to ensure that the wafer 2 does not move or misalign during the process.

[0040] The following formula is the Coulomb's law formula:

[0041]

[0042] Where F is the electrostatic attraction; K is the Coulomb constant; Q is the charge on the upper surface 111; q is the charge on the lower surface of wafer 2; and r is the distance between the lower surface of wafer 2 and the upper surface 111 of chuck body 11 (for JR type electrostatic chuck).

[0043] According to Coulomb's law, the electrostatic attraction F is proportional to the square of the distance r. Therefore, the magnitude of the electrostatic attraction F mainly depends on the size of the distance r; the smaller the distance r, the greater the electrostatic attraction F. Furthermore, the electrostatic attraction F is proportional to the charge Q on the upper surface 111. Therefore, the larger the area of ​​the upper surface 111 excluding the protrusion structure and the air passage structure, the greater the electrostatic attraction F.

[0044] Based on the above principle, optionally, the preset distance between the bearing surface formed by the multiple bumps 13 and the upper surface 111 of the chuck body 11 is greater than or equal to 2μm and less than or equal to 10μm. By setting the preset distance within this range, it can be ensured that the electrostatic attraction F will not be insufficient due to the preset distance being too large, which may cause the wafer 2 to move or misalign during the process; it can also be ensured that the thermal conductivity of the back-blown gas will not be reduced due to the preset distance being less than the molecular mean free path of the back-blown gas introduced between the wafer 2 and the upper surface 111 during the process, which would affect the temperature control capability of the electrostatic chuck.

[0045] Alternatively, the total projected area of ​​the plurality of bumps 13 on the upper surface 111 of the chuck body 11 is greater than or equal to 2% and less than or equal to 10% of the area of ​​the upper surface 111. By setting the above percentage within this range, it can be ensured that the area of ​​the upper surface 111 is not insufficient due to the percentage being too large, which would result in insufficient charge Q on the upper surface 111 and ultimately insufficient electrostatic attraction F. At the same time, it can be ensured that uniform and stable support for the wafer 2 cannot be achieved due to the percentage being too small.

[0046] In some alternative embodiments, the plurality of protrusions 13 can be evenly distributed on a plurality of circles with different radii centered at the center of the upper surface 111 in the non-airway region, for example... Figure 5 The diagram shows the arrangement of the plurality of protrusions 13. Alternatively, they can be arranged in an array in non-airway regions, such as a rectangular array or an array of any other shape. The present invention does not impose any particular limitation on the number or arrangement of the plurality of protrusions 13.

[0047] In some alternative embodiments, the bump 13 can be made of TAC (hydrogen-free diamond-like carbon) material and fabricated using a filtered cathode vacuum arc (FCVA) method. Bumps fabricated using this method exhibit good wear resistance and can withstand high temperatures, thereby improving the lifespan of the electrostatic chuck.

[0048] In some optional embodiments, the distance between the electrode 11 and the upper surface 111 of the chuck body 11 is greater than or equal to 0.5 mm and less than or equal to 2 mm. By setting this distance within this range, a better electrostatic attraction F can be obtained.

[0049] Please see Figure 2 The central air inlet 112 is located at the center of the upper surface 111 of the chuck body 11, and is used to introduce back-blown gas between the upper surface 111 and the wafer 2 to achieve heat exchange between the two, thereby achieving temperature control of the electrostatic chuck.

[0050] Please see Figure 2 The airway structure includes an annular airway 31, a main airway group, and a secondary airway group. The annular airway 31 is located near the edge of the upper surface 111 of the chuck body 11 and is used to define the heat exchange area (including the inner ring region 111a and the outer ring region 111b) on its inner side. Since the edge region 111c of the upper surface 111 of the chuck body 11 is connected to the interior of the chamber, the air pressure in this region will drop sharply, causing the back-blown gas to be unable to exchange heat in the edge region 111c. In this case, with the help of the annular airway 31, the air pressure in the heat exchange area (including the inner ring region 111a and the outer ring region 111b) inside the annular airway 31 can be guaranteed not to be affected by the chamber pressure, ensuring the stability of the air pressure and enabling the back-blown gas to exchange heat normally.

[0051] In some optional embodiments, the diameter of the annular centerline of the annular air passage 31 is greater than or equal to 270 mm and less than or equal to 290 mm, preferably 280 mm; the radial width of the annular air passage 31 is greater than or equal to 0.5 mm and less than or equal to 3 mm, preferably 2 mm; and the depth of the annular air passage 31 is greater than or equal to 0.1 mm and less than or equal to 0.4 mm, preferably 0.2 mm. The aforementioned ranges for the diameter, radial width, and depth of the annular air passage 31 ensure that the area of ​​the heat exchange region is maximized while also ensuring that the air pressure within the heat exchange region inside the annular air passage 31 is not affected by the chamber pressure, thus guaranteeing air pressure stability and enabling the back-blown gas to perform normal heat exchange.

[0052] Both the main air duct assembly and the secondary air duct assembly are located in the aforementioned heat exchange area. The main air duct assembly surrounds the central air inlet 112, for example, located in... Figure 2 The inner ring region 111a; the secondary airway group surrounds the main airway group, for example, located in Figure 2 The outer ring region 111b is defined as follows: the main air passage group is connected to the central air inlet 112 and the secondary air passage group respectively, and is configured to increase the speed at which the back-blown gas flowing out of the central air inlet 112 is delivered to the secondary air passage group, thereby ensuring that the back-blown gas can quickly diffuse from the central air inlet 112 to the surrounding area, that is, to increase the diffusion speed of the back-blown gas. The main air passage group plays a major role in enabling the back-blown gas pressure to quickly reach the stability requirements.

[0053] Since the main air duct assembly is located in the inner ring region 111a near the central air inlet 112, and the air pressure at the central air inlet 112 is higher than in other regions, if the projected area of ​​the main air duct assembly on the upper surface 111 of the chuck body 11 is too large, it can easily lead to high air pressure in the inner ring region 111a, causing the wafer to bulge in this region. To solve this problem, the projected area of ​​the main air duct assembly on the upper surface 111 of the chuck body 11 is less than or equal to 50% of the area R of a specified region. This specified area R is the area of ​​a circle with the center of the upper surface 111 as its center and a diameter of a specified diameter, which is the region within the outer periphery of the inner ring region 111a. Optionally, this specified diameter is, for example, 50 mm.

[0054] Of course, the projected area on the upper surface 111 of the chuck body 11 should not be too small, so as to ensure that the back-blown gas can quickly diffuse from the central air inlet 112 to the surrounding areas, so that the back-blown air pressure can quickly reach the stability requirements.

[0055] In some optional embodiments, the aforementioned main air duct group includes multiple main air ducts 32 evenly distributed circumferentially around the central air inlet 112. Each main air duct 32 is arranged radially along the central air inlet to minimize the path of the back-blown gas to the outer ring region 111b, thereby ensuring that the back-blown gas can quickly diffuse from the central air inlet 112 to the surrounding areas. Furthermore, the inlet end of each main air duct 32 is connected to the central air inlet 112, and the outlet end of each main air duct 32 is connected to the secondary air duct group. The back-blown gas flowing out through the central air inlet 112 simultaneously diffuses to the surrounding areas through each main air duct 32 and flows into the secondary air duct group.

[0056] In some optional embodiments, the projected area of ​​the main air passage group on the upper surface 111 of the chuck body 11 can be adjusted by setting parameters such as the number, width, and depth of the main air passages 32. For example, the width of the main air passage 32 is greater than or equal to 0.5 mm and less than or equal to 3 mm, preferably 2 mm; the depth of the main air passage 32 is greater than or equal to 0.1 mm and less than or equal to 0.4 mm, preferably 0.2 mm; the number of main air passages 32 is greater than or equal to 9 and less than or equal to 20, preferably 10. For example Figure 2 The diagram shows 15 main air channels 32. By setting the number, width, and depth of the main air channels 32 within the aforementioned range, it is possible to ensure that the projected area of ​​the main air channel group on the upper surface 111 of the chuck body 11 is not too large, which would result in high air pressure in the inner ring region 111a and cause the wafer to "bulge" in that region. At the same time, it is possible to ensure that the projected area on the upper surface 111 of the chuck body 11 is large enough so that the back-blown gas can quickly diffuse from the central air inlet 112 to the surrounding areas, thereby achieving a rapid and stable back-blown air pressure.

[0057] It should be noted that the main airway assembly is not limited to the structure used in the above embodiments. In practical applications, any other structure can be used, as long as it can enable the back blow pressure to quickly reach the stability requirements.

[0058] The secondary air duct group is connected to both the main air duct group and the annular air duct 31, and is configured to ensure uniform distribution of the back-blown gas at different locations within the heat exchange area (including the inner ring region 111a and the outer ring region 111b). In other words, the secondary air duct group enables rapid and uniform diffusion of the back-blown gas. The secondary air duct group plays a key role in quickly achieving the required uniformity of the back-blown gas. Therefore, by combining the main air duct group and the secondary air duct group, the back-blown gas ventilation time can be effectively shortened while ensuring the stability and uniformity of the back-blown gas pressure, thereby increasing equipment productivity.

[0059] It should be noted that, since the distance between the gas channel areas where the main gas channel group and the secondary gas channel group are located and the wafer surface is relatively large, while the distance between the non-gas channel area on the upper surface 111 and the wafer surface is relatively small, the main gas channel group and the secondary gas channel group can guide the diffusion of the back-blown gas. At the same time, both are connected to the non-gas channel area. Therefore, after the back-blown gas flows along the main gas channel group and the secondary gas channel group in sequence, it will further diffuse into the non-gas channel area, and finally fill the entire heat exchange area with back-blown gas, thereby achieving uniform and stable gas pressure between the heat exchange area and the wafer surface.

[0060] In some alternative embodiments, the secondary airway group includes a primary sub-airway group, such as Figure 2 As shown, this sub-airway group is located in the outer ring region 111b and includes multiple secondary airways 33. The outlet end of each main airway 32 is connected to the inlet ends of two of the secondary airways 33. The two secondary airways 33 connected to the same main airway 32 extend from the outlet end of the main airway 32 in different directions away from the central air inlet 112. For example, Figure 2 Two secondary air passages 33, which are connected to the same main air passage 32, extend away from the central air inlet 112 and away from each other, and finally connect with the annular air passage 31. Since each pair of secondary air passages 33 serves as two branches of the main air passage 32, the back-blown gas flowing out of the main air passage 32 can be further diffused from the outlet of the main air passage 32 in different directions away from the central air inlet 112, thereby enabling the back-blown gas to quickly reach the required uniformity.

[0061] It should be noted that in practical applications, the number of secondary air passages 33 connected to the same main air passage 32 can also be one. In this case, different secondary air passages 33 can be interconnected, which can also achieve the effect of quickly achieving the uniformity requirement of the back-blown gas. Alternatively, the number of secondary air passages 33 connected to the same main air passage 32 can be three or more, for example, as shown below. Figure 3 As shown, the number of secondary airways 33 connected to the same main airway 32 can also be 3, and this number can be freely set according to specific needs.

[0062] In some optional embodiments, the width of the secondary air passage 33 is greater than or equal to 0.5 mm and less than or equal to 3 mm, preferably 2 mm; the depth of the secondary air passage 33 is greater than or equal to 0.1 mm and less than or equal to 0.4 mm, preferably 0.2 mm; and the number of secondary air passages 33 is greater than or equal to 9 and less than or equal to 100, preferably 20. By setting the width, depth, and number of secondary air passages 33 within the above-mentioned value range, the back-blown gas can be effectively made to quickly achieve the required uniformity.

[0063] It should also be noted that the aforementioned secondary air passage 33 is not limited to a straight channel; it can also be any other channel of any shape, such as a curved channel or a zigzag channel. The present invention does not impose any particular restrictions on this.

[0064] Second Embodiment

[0065] Please see Figure 4 The electrostatic chuck provided in this embodiment differs from the first embodiment described above only in that the structure of the secondary airway group is different, and multiple transition airways 34 are added. The differences between this embodiment and the first embodiment described above will be described in detail below.

[0066] Specifically, such as Figure 4 As shown, on the upper surface 111 of the chuck body 11, an annular transition region 111d is further divided between the outer ring region 111b and the annular air passage 31. Based on this, the secondary air passage group includes a primary sub-air passage group located in the outer ring region 111b and comprising multiple secondary air passages 33. The outlet end of each primary air passage 32 is connected to the inlet ends of two secondary air passages 33. Furthermore, the two secondary air passages 33 connected to the same primary air passage 32 extend from the outlet end of the primary air passage 32 in different directions away from the central air inlet 112. For example, Figure 2 Two secondary air passages 33 connected to the same main air passage 32 extend away from the central air inlet 112 and away from each other. Furthermore, the outlets of any two adjacent secondary air passages 33 connected to different main air passages 32 converge to form a common outlet A, thereby enabling the two secondary air passages 33 to be interconnected, which can further improve the efficiency of the back-blown gas to quickly achieve the uniformity requirements.

[0067] Furthermore, the aforementioned secondary airway group also includes multiple transition airways 34, which are located in the aforementioned annular transition region 111d. The inlet of each transition airway 34 is connected to a common outlet A, and the outlet of each transition airway 34 is connected to the annular airway 31. Through the transition airways 34, the interconnected secondary airways 33 can be further connected to the annular airway 31.

[0068] It should be noted that in practical applications, the aforementioned transition airway 34 can be omitted, that is, the aforementioned annular transition area 111d can be omitted, and the aforementioned common air outlet A can be directly extended to the location of the annular airway 31 and connected to it.

[0069] The other structures and functions of the electrostatic chuck provided in this embodiment are the same as those in the first embodiment described above, and will not be repeated here.

[0070] Third Embodiment

[0071] As a preferred embodiment, please refer to Figure 5 and Figure 6 The electrostatic chuck provided in this embodiment differs from the first and second embodiments described above only in the structure of the secondary airway assembly. The differences between this embodiment and the first and second embodiments will be described in detail below.

[0072] like Figure 5 and Figure 6 As shown, the secondary airway group comprises two levels of sub-airway groups that are sequentially arranged in a direction away from the central air inlet 112, and both are located in the aforementioned outer ring region. The two levels of sub-airway groups are the first-level airway group and the second-level airway group, wherein the first-level airway group includes multiple primary airways 33a, and the second-level airway group includes multiple secondary airways 33b.

[0073] Each main airway 32 has its outlet end connected to the inlet end of three primary airways 33a. Among the three primary airways connected to the same main airway 32, the middle primary airway 331 is coaxial with the main airway 32, and the two secondary primary airways 332 are symmetrically distributed relative to the middle primary airway 331. Furthermore, the outlet ends of any two adjacent primary airways 331 connected to different main airways 32 converge to form a first common outlet end A1. Among the three primary airways connected to the same main airway 32, the outlet end of the middle primary airway 331 is connected to two secondary airways 33b. The air inlet is connected to the air outlet, and each first common air outlet A1 is connected to the air inlet of two of the second air passages 33b; and any two adjacent second air passages 33b connected to the air outlet of the first air passage 331 and connected to the first common air outlet A1 converge to form a second common air outlet A2, or in other words, any two adjacent second air passages 33b connected to different air outlets (including the air outlet of the first air passage 331 and the first common air outlet A1) converge to form a second common air outlet A2, and the second common air outlet 33b is connected to the annular air passage 31.

[0074] Optionally, the above-mentioned secondary airway group also includes multiple transition airways 34, with the air inlet of each transition airway 34 connected to each of the second common air outlets A2, and the air outlet of each transition airway 34 connected to the annular airway 31.

[0075] The following is based on Figure 5 The experiment was conducted using the airway structure of the electrostatic chuck shown as an example. The specific parameters include: the width of the main airway 32, the secondary airway 33, the annular airway 31 and the transition airway 34 are all 2 mm; the number of main airways 32 is 15; the total number of secondary airways is 60; and the diameter of the annular center line of the annular airway 31 is 280 mm.

[0076] Figure 7 This is a comparison graph showing the average air pressure versus time curves of the electrostatic chuck used in the third embodiment of the present invention and the electrostatic chuck of the prior art. Figure 7As shown, when the average air pressure reaches line B1, it is considered that the average air pressure meets the process requirements; when the average air pressure reaches line B2, it is considered that the stability of the average air pressure meets the process requirements, and the PVD process can begin at this time. Typically, the value of B1 is 90% of the value of B2. Curve S1 is the curve of average air pressure versus time for the electrostatic chuck in the prior art; curve S2 is the curve of average air pressure versus time for the electrostatic chuck used in the third embodiment of this invention. By comparison, it can be seen that the time point t2 (over 100s) corresponding to line B1 on curve S1 is greater than the time point t1 (around 12s) corresponding to line B1 on curve S2. That is, the electrostatic chuck used in the third embodiment of this invention can reach lines B1 and B2 faster than the prior art. This proves that the electrostatic chuck provided in this embodiment can effectively shorten the back-blowing gas ventilation time while ensuring that the back-blowing air pressure meets the stability requirements.

[0077] Figure 8 This is a comparison graph showing the relationship between air pressure and wafer position between the electrostatic chuck used in the third embodiment of the present invention and a prior art electrostatic chuck. (See attached graph.) Figure 8 As shown, curve S1 is the curve of the electrostatic chuck in the prior art regarding gas pressure and wafer position; curve S2 is the curve of the electrostatic chuck used in the third embodiment of the present invention regarding gas pressure and wafer position. By comparison, it can be seen that the gas pressure in curve S1 gradually decreases from the center (150mm) of the wafer to the edge, with the highest gas pressure at the center being 680Pa and the lowest at the edge being 340Pa, indicating poor gas pressure uniformity. In contrast, curve S2 shows a very small difference in gas pressure between the center (150mm) and the edge, both around 680Pa. This demonstrates that the electrostatic chuck provided in this embodiment can effectively improve the stability of back-blown gas pressure.

[0078] It should be noted that the above third embodiment is only a preferred embodiment, and the present invention is not limited thereto. In practical applications, the secondary airway group may also include three or more sub-airway groups that are sequentially arranged in a direction away from the central air inlet 112. In this case, the outlet end of each main airway 32 is connected to the inlet end of at least one secondary airway in the adjacent first-level sub-airway group, and multiple secondary airways connected to the same main airway 32 extend from the outlet end of the main airway 32 in different directions away from the central air inlet 112; the outlet end of each secondary airway in the upstream level is connected to the inlet end of at least one secondary airway in the adjacent downstream level, and multiple secondary airways in the downstream level connected to the same primary airway in the upstream level extend from the outlet end of the secondary airway in the upstream level in different directions away from the central air inlet 112.

[0079] The other structures and functions of the electrostatic chuck provided in this embodiment are the same as those in the first and second embodiments described above, and will not be repeated here.

[0080] In summary, the electrostatic chucks provided in the above embodiments of the present invention, by combining the main air duct group and the secondary air duct group, can effectively shorten the back-blowing gas ventilation time while ensuring the stability and uniformity of the back-blowing gas pressure, thereby improving equipment productivity.

[0081] As another technical solution, embodiments of the present invention also provide a semiconductor processing apparatus, including a process chamber and an electrostatic chuck disposed in the process chamber, wherein the electrostatic chuck adopts the electrostatic chuck provided in the above embodiments of the present invention.

[0082] The semiconductor processing equipment provided in this embodiment of the invention, by employing the electrostatic chuck provided in this embodiment of the invention, can effectively shorten the back-blowing gas passage time while ensuring that the back-blowing gas pressure meets the requirements of stability and uniformity, thereby improving the equipment's production capacity.

[0083] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An electrostatic chuck, used in semiconductor processing equipment, comprising a chuck body, characterized in that, The upper surface of the chuck body is provided with a central air inlet and an air passage structure; The air passage structure includes an annular air passage, a main air passage group, and a secondary air passage group. The annular air passage is located at the edge of the upper surface of the chuck body to define a heat exchange area inside it. The main air passage group and the secondary air passage group are both distributed in the heat exchange area, and the main air passage group surrounds the central air inlet, while the secondary air passage group surrounds the main air passage group. The main air duct group includes multiple main air ducts evenly distributed around the central air inlet. Each main air duct is arranged radially along the central air inlet. The air inlet end of each main air duct is connected to the central air inlet, and the air outlet end of each main air duct is connected to the secondary air duct group. The secondary airway group comprises multiple levels of sub-airway groups arranged sequentially in a direction away from the central air inlet. Each level of the sub-airway group includes multiple secondary airways. The outlet end of each main airway is connected to the inlet ends of multiple secondary airways in the adjacent level of the sub-airway group. Multiple secondary airways connected to the same main airway extend from the outlet end of that main airway in different directions away from the central air inlet. The outlet end of each secondary airway in the upstream level is connected to multiple secondary airways in the adjacent downstream level. The inlet end of the channel is connected to the same primary air channel of the upstream level. Multiple secondary air channels of the downstream level extend from the outlet end of the secondary air channel of the upstream level in different directions away from the central inlet. Each secondary air channel of the sub-air channel group adjacent to the annular air channel converges with the adjacent secondary air channel to form a common outlet end, which is connected to the annular air channel. At least two of the outlet ends of all adjacent secondary air channels of other sub-air channel groups not adjacent to the annular air channel converge to form a common outlet end.

2. The electrostatic chuck according to claim 1, characterized in that, The width of the secondary airway is greater than or equal to 0.5 mm and less than or equal to 3 mm; the depth of the secondary airway is greater than or equal to 0.1 mm and less than or equal to 0.4 mm; and the number of the secondary airways is greater than or equal to 9 and less than or equal to 100.

3. The electrostatic chuck according to claim 1, characterized in that, The secondary airway group includes two levels of sub-airway groups, namely a first-level airway group and a second-level airway group. The first-level airway group includes multiple primary airways. The outlet of each primary airway is connected to the inlet of three primary airways. Among the three primary airways connected to the same primary airway, the middle primary airway is coaxial with the primary airway, and the two primary airways on both sides are symmetrically distributed relative to the middle primary airway. Furthermore, the outlets of the two primary airways on both sides converge with the outlets of the adjacent primary airways to form a first common outlet. The second-level airway group includes multiple secondary airways. Among the three primary airways connected to the same main airway, the outlet of the middle primary airway is connected to the inlet of two of the secondary airways. Each first common outlet is connected to the inlet of two of the secondary airways. Furthermore, the outlet of each secondary airway converges with the outlet of the adjacent secondary airway to form a second common outlet, which is connected to the annular airway.

4. The electrostatic chuck according to claim 1 or 3, characterized in that, The secondary airway group also includes multiple transition airways, the inlet of each of the transition airways being connected to the common outlet of each of the adjacent annular airways, and the outlet of each of the transition airways being connected to the annular airway.

5. The electrostatic chuck according to any one of claims 1-3, characterized in that, The diameter of the annular airway's centerline is greater than or equal to 270 mm and less than or equal to 290 mm; the radial width of the annular airway is greater than or equal to 0.5 mm and less than or equal to 3 mm; and the depth of the annular airway is greater than or equal to 0.1 mm and less than or equal to 0.4 mm.

6. The electrostatic chuck according to claim 1, characterized in that, The upper surface of the chuck body is also provided with a bump structure. The bump structure is located in the non-gas channel area of ​​the upper surface of the chuck body and is used to support the wafer. The bearing surface of the bump structure and the upper surface of the chuck body have a preset distance. The bump structure includes multiple bumps evenly distributed in the non-airway region. The total orthographic projection area of ​​the multiple bumps on the upper surface of the chuck body accounts for more than 2% and less than or equal to 10% of the upper surface area of ​​the chuck body.

7. The electrostatic chuck according to claim 6, characterized in that, The preset spacing is greater than or equal to 2μm and less than or equal to 10μm.

8. A semiconductor processing apparatus, comprising a process chamber and an electrostatic chuck disposed in the process chamber, characterized in that, The electrostatic chuck is the electrostatic chuck described in any one of claims 1-7.

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