Porous plug assembly, electrostatic chuck and plasma etching apparatus

Abstract

The present invention discloses a porous plug assembly, an electrostatic chuck, and a plasma etching apparatus. The porous plug assembly includes a porous plug body having a porous structure, in which gas enters from the bottom surface of the porous plug body, passes through the porous plug body, and exits from the top surface of the porous plug body. The porous plug assembly also includes an insulating dense layer having side portions and lateral portions, the side portions being formed on side walls of the porous plug body, and the lateral portions extending from tips of the lateral portions in at least one direction between a direction away from the porous plug body and a direction toward the porous plug body. The lateral portions reduce the risk of the adhesive layer being corroded by plasma. The porous plug assembly also reduces the discharge space and the risk of arcing. Furthermore, the porous plug assembly can effectively solve the problem of the adhesive layer clogging the porous plug body.

Description

[Technical Field]

[0001] The present invention relates to the field of plasma equipment, and more particularly to porous plug assemblies, electrostatic chucks, and plasma etching apparatus. [Background technology]

[0002] The electrostatic chuck is a core component of a plasma etching system. A dielectric plate is attached to the base of the electrostatic chuck as a support platform for the wafer. The electrostatic chuck is also equipped with gas holes through which cooling gas flows to the backside of the wafer, absorbing heat and lowering its temperature. With the development of storage technology, the radio frequency power used in plasma etching systems has become increasingly higher, and the voltage applied to the electrostatic chuck has also become increasingly higher. When processing a wafer with plasma, the cooling gas in the gas holes is likely to break down, causing arcing and damaging the wafer and the electrostatic chuck.

[0003] In the prior art, the breakdown resistance voltage of the gas hole is improved by disposing a porous plug in the gas hole. However, currently, increasingly stringent process requirements, uncertainties in the manufacturing process, and various influences that occur during the use of the electrostatic chuck (e.g., adverse effects due to thermal expansion and contraction of the electrostatic chuck) have placed even higher requirements on the breakdown resistance of the porous plug. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a porous plug assembly, an electrostatic chuck, and a plasma etching apparatus that are breakdown resistant. [Means for solving the problem]

[0005] In order to achieve the above object, the present invention provides a porous plug assembly, comprising: a porous plug body having a porous structure, the porous plug body including a top surface, a bottom surface, and a side wall, wherein gas can enter from the bottom surface and pass through the porous plug body and exit from the top surface; and an insulating dense layer including a side portion and a lateral portion, the side portion being provided on the side wall of the porous plug body, the side portion having a tip and a bottom end, the bottom end being flush with the bottom surface, and the tip being not lower than the top surface, the lateral portion extending from the tip of the lateral portion in at least one direction away from the porous plug body and towards the porous plug body, and the upper surface of the lateral portion being flush with the tip.

[0006] Optionally, the lateral portion extends at least in a direction approaching the porous plug body, and a lower surface of the lateral portion is not higher than the top surface.

[0007] Optionally, the lower surface of the lateral portion is flush with and covers a portion of the top surface.

[0008] Optionally, the lower surface of the lateral portion is lower than the top surface, and the area of ​​the top surface is smaller than the area of ​​the bottom surface.

[0009] Optionally, the lateral portion further extends away from the porous plug body.

[0010] Optionally, the bottom ends of the side portions are provided with elastic members.

[0011] Optionally, the porosity of the porous plug body is 30% to 60%.

[0012] Optionally, the porous plug body is a porous ceramic and the dense layer is a ceramic.

[0013] The present invention further provides an electrostatic chuck, comprising: a base having a first through hole, the base having the above-mentioned porous plug assembly disposed in the first through hole; and a dielectric plate having an electrode for generating an electrostatic attraction, the upper surface of the dielectric plate being used to fix a wafer, the lower surface of the dielectric plate being connected to the base via an adhesive layer, the lateral portion including a dielectric plate positioned between the lower surface of the dielectric plate and the base, the dielectric plate having a second through hole axially penetrating the dielectric plate, the second through hole communicating with the first through hole.

[0014] Optionally, the lateral portion extends at least in a direction away from the porous plug body, and an adhesive layer is provided between a lower surface of the lateral portion and the base.

[0015] Optionally, the upper surface of the base is stepped, having a relatively low first upper surface and a relatively high second upper surface, and an adhesive layer is provided between the lower surface of the lateral portion and the first upper surface.

[0016] Optionally, an insulating layer is provided between the adhesive layer and the base.

[0017] Optionally, the insulating layer is alumina.

[0018] Optionally, an adhesive layer is provided between the side portion and the base.

[0019] The present invention further provides a plasma etching apparatus comprising a reaction chamber, the above-described electrostatic chuck, an upper electrode, a cooling device, and a high-frequency power supply, wherein the electrostatic chuck is disposed in the reaction chamber and is used to support a wafer and serves as a lower electrode of the reaction chamber, the cooling device is in communication with the electrostatic chuck and is used to deliver a cooling gas to the wafer, the upper electrode is disposed opposite the electrostatic chuck, and a high-frequency power supply is applied to the upper electrode or the electrostatic chuck to generate a high-frequency electric field between the upper electrode and the electrostatic chuck, thereby dissociating a reactive gas into plasma and etching the wafer. [Effects of the Invention]

[0020] Compared with the prior art, the present invention includes at least the following beneficial effects:

[0021] (1) The porous plug assembly of the present invention includes a porous plug body having a porous structure and an insulating dense layer. The dense layer includes a side portion and a lateral portion. The lateral portion can effectively protect the adhesive layer, reducing the risk of the adhesive layer being corroded by plasma and improving the corrosion resistance of the electrostatic chuck.

[0022] (2) The lateral portions of the dense layer of the present invention can prevent the adhesive layer from entering the top surface of the porous plug body and blocking the pores of the porous plug body.

[0023] (3) In the present invention, an adhesive layer is provided between the lateral portion of the dense layer and the base, and an elastic member is provided at the bottom end of the lateral portion of the dense layer, which provides compensation for the slit between the dielectric plate and the lateral portion of the dense layer and prevents arcing due to the slit being too large.

[0024] (4) The dense layer of the present invention also reduces the discharge space and the risk of arcing. The outwardly extending lateral portions overlap with the adhesive layer and the alumina insulating layer, significantly improving the breakdown resistance voltage. Even if defects exist in the adhesive layer or the alumina insulating layer, the dense layer can exhibit excellent breakdown resistance. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 2 is a structural schematic diagram of a plasma etching chamber. [Figure 2] FIG. 1 is a schematic diagram of a conventional electrostatic chuck structure. [Figure 3] 1 is a structural schematic diagram of a porous plug assembly according to the present invention. FIG. [Figure 4] 1 is a structural schematic diagram of a porous plug assembly according to the present invention. FIG. [Figure 5] 1 is a structural schematic diagram of a porous plug assembly according to the present invention. FIG. [Figure 6] 1 is a structural schematic diagram of a porous plug assembly according to the present invention. FIG. [Figure 7] 1 is a structural schematic diagram of a porous plug assembly according to the present invention. FIG. [Figure 8] 1 is a structural schematic diagram of a porous plug assembly according to the present invention. FIG. [Figure 9] 1 is a structural schematic diagram of an electrostatic chuck according to the present invention; [Figure 10] 1 is a structural schematic diagram of an electrostatic chuck according to the present invention; [Figure 11] 1 is a structural schematic diagram of an electrostatic chuck according to the present invention; [Figure 12] 1 is a structural schematic diagram of an electrostatic chuck according to the present invention; [Figure 13] 1 is a structural schematic diagram of an electrostatic chuck according to the present invention; [Figure 14] 1 is a structural schematic diagram of an electrostatic chuck according to the present invention; [Figure 15] 1 is a structural schematic diagram of an electrostatic chuck according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0026] The technical solutions of the present invention will be described clearly and completely below with reference to the drawings, and it is obvious that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments, and all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without any creative effort are all within the scope of protection of the present invention.

[0027] In the description of the present invention, the orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the orientations or positional relationships shown in the drawings and are merely for the purpose of easily describing or simplifying the description of the present invention. They do not necessarily indicate or imply that the indicated devices or elements must have a specific orientation or be constructed or operated in a specific orientation, and therefore cannot be understood as limitations on the present invention. In addition, the terms "first," "second," and "third" are used merely for the purpose of description and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, unless otherwise clearly specified or limited, the terms "attach," "connect," and "connect" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, an integral connection, a mechanical connection, a direct connection, an indirect connection via an intermediate medium, or internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0029] FIG. 1 shows a plasma processing procedure in a plasma etching chamber. An electrostatic chuck 100 serves as both a support platform for a wafer 200 and a lower electrode in the reaction chamber. An upper electrode 400 in the reaction chamber faces the electrostatic chuck 100. A high-frequency power supply is applied to the upper electrode 400 or the electrostatic chuck 100, generating a high-frequency electric field between the upper electrode 400 and the electrostatic chuck 100, dissociating a reactive gas into plasma 300 and processing the wafer 200 fixed to the electrostatic chuck 100. The electrostatic chuck 100 can also adjust and control the temperature of the wafer 200 placed thereon. The electrostatic chuck 100 is provided with gas holes and is connected to a cooling device 500. Cooling gas from the cooling device 500 flows through the gas holes to the backside of the wafer 200, absorbing heat from the wafer 200 and thereby reducing the temperature of the wafer 200.

[0030] As shown in FIG. 2 , the electrostatic chuck 100 includes a base 110 and a dielectric plate 130 attached to the base 110. The dielectric plate 130 is connected to the base 110 via an adhesive layer 120. The dielectric plate 130 is provided with an electrode for generating an electrostatic attraction force. To adjust the temperature of the wafer 200, the base 110 is provided with a first through-hole 111, and the dielectric plate 130 is provided with a second through-hole 131 axially penetrating the dielectric plate 130. The second through-hole 131 communicates with the first through-hole 111. The first through-hole 111 is connected to a cooling device (not shown) via a passage 112. Cooling gas flows from the cooling device, passes through the passage 112, the first through-hole 111, and the second through-hole 131 in this order, and contacts the back surface of the wafer 200 fixed to the dielectric plate 130, thereby adjusting and controlling the temperature of the wafer 200.

[0031] The high-power high-frequency electric field is likely to cause an arc reaction in the cooling gas in the first through-hole 111, resulting in arc damage to the electrostatic chuck 100. The conditions for the breakdown of the cooling gas include: (1) the voltage difference is greater than the voltage threshold at which the cooling gas breaks down; and (2) the discharge space is sufficiently large, i.e., the discharge space is much larger than the mean free path of the cooling gas, and satisfies the continuity of the arc action.

[0032] In the prior art, a porous plug assembly 700 including a porous plug body 710 and a dense layer 720 is typically provided in the first through-hole 111. The porous plug body 710 has a porous structure, allowing the cooling gas to enter the bottom surface 711 of the porous plug body 710, pass through the porous plug body 710, exit from the top surface 712, enter the second through-hole 131, and contact the wafer 200. After the porous plug assembly 700 is filled, the discharge space of the cooling gas in the first through-hole 111 is reduced, thereby reducing the possibility of breakdown of the cooling gas. The insulating dense layer 720 is provided on the sidewall of the porous plug body 710, thereby improving the breakdown resistance of the porous plug body 710.

[0033] However, as the precision of wafer processing increases, the RF power applied to the electrostatic chuck 100 increases. The high-power RF electric field affects the porous plug assembly 700, and the breakdown resistance of the porous plug assembly 700 must be further improved. When using the porous plug assembly 700 described above, the slit between the dielectric plate 130 and the porous plug assembly 700 is too large (usually the same thickness as the adhesive layer 120), which can cause arc discharge. Arc discharge is particularly likely to occur at the end surface 121 of the adhesive layer 120. The adhesive layer 120 generally uses an organic adhesive, which is more susceptible to plasma corrosion than the dense layer 720. The corroded adhesive layer 120 cannot effectively cover the base 110, increasing the risk of arc discharge.

[0034] Based on this, the present application provides a porous plug assembly that can reduce the risk of breakdown of an electrostatic chuck. As shown in FIGS. 3 to 8 , the present application provides a porous plug assembly 600 that includes a porous plug body 610 having a porous structure and an insulating dense layer 620. The porous plug body 610 may be cylindrical or have any other shape, and the dense layer 620 surrounds the sidewall of the porous plug body 610. The porous plug body 610 may be made of porous ceramic, such as alumina or aluminum nitride, and the through-holes in the porous ceramic may be straight or curved.

[0035] The cooling gas enters the porous plug body 610 from a bottom surface 611, passes through the porous plug body 610, and exits from a top surface 612 of the porous plug body 610. Optionally, the porosity of the porous plug body 610 is 30% to 60%. If the porosity is too small, the flow rate of the cooling gas passing through the porous plug body 610 is too small, and if the porosity is too large, the pressure resistance of the porous plug body 610 is too low. Preferably, the porosity of the porous plug body 610 is 50%.

[0036] The dense layer 620 includes a side portion 621 and a lateral portion 622, the side portion 621 being formed on a side wall of the porous plug body 610, and the lateral portion 622 being formed at a tip 6211 of the side portion 621, and the lateral portion 622 extending in at least one direction away from the porous plug body 610 (i.e., outward) and approaching the porous plug body 610 (i.e., inward). The upper surface of the lateral portion 622 is substantially flush with the tip 6211 of the lateral portion 621. The dense layer 620 is made of at least one of ceramic, epoxy resin, and silicone resin.

[0037] 3 , the lateral portions 622 extend outward, and the top surface 612 of the porous plug body is not covered with the dense layer 620. In this embodiment, the upper surfaces of the lateral portions 622 and the tips 6211 of the lateral portions 621 are substantially flush with the top surface 612 of the porous plug body 610, and the bottom ends 6212 of the lateral portions 621 are substantially flush with the bottom surface 611 of the porous plug body 610.

[0038] In the embodiment shown in Figure 4, the bottom end 6212 of the lateral portion 621 is approximately flush with the bottom surface 611 of the porous plug body 610, and the tip 6211 of the lateral portion 621 is higher than the top surface 612 of the porous plug body 610, i.e., the distance from the bottom end 6212 to the tip 6211 of the lateral portion 621 is greater than the axial length of the porous plug body 610.

[0039] In the embodiment shown in FIG. 5, the lateral portions 622 extend inward, and the lower surfaces of the lateral portions 622 are substantially flush with the top surface 612, i.e., the lateral portions 622 cover a portion of the top surface 612, and gas flows out from the areas of the top surface 612 that are not covered by the dense layer 620.

[0040] 6 , the lateral portions 622 extend inward, and the upper surface of the lateral portions 622 is not lower than the top surface 612, the lower surface of the lateral portions 622 is lower than the top surface 612, the area of ​​the top surface 612 is smaller than the bottom surface 611, and the porous plug body 610 has a generally convex shape. In this case, the distance from the bottom end 6212 to the tip 6211 of the lateral portions 621 is not smaller than the distance from the bottom surface 611 to the top surface 612 of the porous plug body 610.

[0041] Compared with FIGS. 5 and 6, in the embodiment shown in FIGS. 7 and 8, the lateral portions 622 extend inward and outward at the same time, and the cross section of the dense layer 620 has a substantially T-shaped structure.

[0042] The present invention further provides an electrostatic chuck including the porous plug assembly 600. As shown in FIG. 9 , a first through-hole 111 is formed in a base 110 of the electrostatic chuck, and the porous plug assembly 600 is disposed in the first through-hole 111. A dielectric plate 130 is disposed on the base 110, and an upper surface of the dielectric plate 130 is used to fix a lateral portion of a wafer. A second through-hole 131 is formed in the dielectric plate 130, axially penetrating the dielectric plate 130, and the second through-hole 131 is connected to the first through-hole 111. An adhesive layer 120 is provided between the lower surface of the dielectric plate 130 and the base 110 to bond the dielectric plate 130 to the base 110.

[0043] In this embodiment, the lateral portions 622 extend outward, so that the adhesive layer 120 is surrounded by the base 110, the dense layer 620, and the dielectric plate 130. The end surface 121 of the adhesive layer 120 is shielded by the dense layer 620 and is not directly exposed to the plasma environment. The dense layer 620 has good corrosion resistance and can protect the end surface 121 of the adhesive layer 120. Compared with the prior art, the discharge space between the dielectric plate 130 and the porous plug assembly 600 is relatively small, which is unfavorable for the occurrence of arc discharge. The dense layer 620 also has a very high breakdown resistance voltage, which can improve the breakdown resistance of the peripheral region of the porous plug body 610.

[0044] 10 , the upper surface of the lateral portion 622 is higher than the top surface 612 of the porous plug body 610. In this embodiment, a gap 6120 exists between the lower surface of the dielectric plate 130 and the top surface 612. The dielectric plate 130 does not contact the top surface 612, which can reduce the obstruction of gas outflow caused by the dielectric plate 130. The dense layer 620 has a very high breakdown voltage and can improve the breakdown resistance of the peripheral region of the porous plug body 610.

[0045] In the embodiment shown in FIG. 11 , the lateral portions 622 extend inward. The dielectric plate 130 is disposed on the lateral portions 622 of the dense layer 620, and the upper surface of the base 110 is not higher than the upper surface of the lateral portions 622. The adhesive layer 120 is filled between the base 110 and the dielectric plate 130. The adhesive layer 120 is surrounded by the base 110, the dense layer 620, and the dielectric plate 130. The end surface 121 of the adhesive layer 120 is shielded by the dense layer 620 and is not directly exposed to the plasma environment. The extended lateral portions 622 cover a portion of the top surface 612, preventing the plasma from penetrating the lateral portions 622 of the dense layer 620 along the top surface 612 of the porous plug body 610 and corroding the adhesive layer 120.

[0046] The adhesive layer 120 is typically formed of a fluid gel-like material. When the adhesive layer 120 is processed, the gel-like material tends to flow into the porous plug body 610, causing pore clogging and affecting the breathability of the porous plug body 610. In this embodiment, the lateral portions 622 of the dense layer 620 cover a portion of the top surface 612. The extended lateral portions 622 increase the distance between the adhesive layer 120 and the region of the top surface 612 of the porous plug body 610 from which gas flows (i.e., the region not covered by the lateral portions 622). This reduces the likelihood of the adhesive layer 120 flowing onto the top surface 612 of the porous plug body 610 and causing pore clogging. The outwardly extending lateral portions 622 also serve to prevent pore clogging by the adhesive gel-like material. Compared to the prior art, the discharge space between the dielectric plate 130 and the porous plug assembly 600 is relatively small, which is unfavorable for arc discharge. The dense layer 620 also has a very high breakdown voltage resistance, and can improve the breakdown resistance of the peripheral region of the porous plug body 610 .

[0047] Typically, when fabricating an electrostatic chuck, a first through-hole is first formed in the base, and a porous plug assembly is inserted into the first through-hole. A dielectric plate is then bonded to the base via an adhesive layer. The dielectric plate is then pressed axially to reduce the gap between the dielectric plate and the lateral portions of the dense layer, firmly adhering the dielectric plate to the base. The lower surface of the dielectric plate is adjacent to the upper surface of the lateral portion. If a gap exists between the two surfaces, the gap is favorable for preventing arcing. However, due to the potential for tolerances in the production process, errors during processing, and the relatively brittle material of the dielectric plate, if the porous plug assembly and the base are both hard-contact, pressing the dielectric plate axially may cause the dielectric plate to burst. The gap between the lower surface of the dielectric plate and the upper surface of the lateral portion may be relatively large.

[0048] As shown in FIG. 12 , in the present invention, an adhesive layer 120 is further installed between the lower surface of the lateral portion 622 and the base 110. Specifically, the upper surface of the base 110 is stepped, having a relatively low first upper surface and a relatively high second upper surface, and the adhesive layer 120 is installed between the lower surface of the lateral portion 622 and the first upper surface. The adhesive layer 120 is a soft gel-like material. When the dielectric plate 130 is pressed against the base 110, the adhesive layer 120 between the lower surface of the lateral portion 622 and the base 110 can compensate for the slit 6121 between the upper surface of the lateral portion 622 and the dielectric plate 130. After bonding, the width of the slit 6121 is 0.1 mm or less, thereby eliminating the slit 6121 and achieving a perfect bonding between the lateral portion 622 and the dielectric plate 130.

[0049] In other embodiments, particularly for those in which the lateral portions 622 extend inward, the lateral portions 622 do not overlap the base 110, and the slits 6121 cannot be compensated for by providing the adhesive layer 120 on the lateral portions 622. To ensure sufficient bonding between the lateral portions 622 and the dielectric plate 130, in the embodiment shown in FIG. 13 , an elastic member 630 is provided at the bottom end of the lateral portion 621 of the dense layer 620. When the dielectric plate 130 is pressed, the entire porous plug assembly 600 moves downward along the axial direction together with the dielectric plate 130, and the elastic member 630 is compressed between the porous plug assembly 600 and the base 110 to compensate for the slits between the lateral portions 622 and the dielectric plate 130.

[0050] In another embodiment, an insulating layer is provided between the adhesive layer 120 and the base 110. The insulating layer is made of alumina, which can further protect the base and prevent direct arc damage between the base 110 and the wafer 200.

[0051] In another embodiment, an adhesive layer is provided between the side portion 621 and the base 110. The adhesive layer 120 between the lower surface of the dielectric plate 130 and the base 110, the adhesive layer 120 between the lower surface of the lateral portion 622 and the base 110, and the adhesive layer between the side portion 621 and the base 110 are in communication with each other.

[0052] The present invention further provides a plasma etching apparatus comprising a reaction chamber, the above-described electrostatic chuck, an upper electrode, a cooling device, and a high-frequency power supply, wherein the electrostatic chuck is disposed in the reaction chamber and is used to support a wafer and serves as a lower electrode of the reaction chamber, the cooling device is in communication with the electrostatic chuck and is used to deliver a cooling gas to the wafer, the upper electrode is disposed opposite the electrostatic chuck, and a high-frequency power supply is applied to the upper electrode or the electrostatic chuck, and a high-frequency electric field is generated between the upper electrode and the electrostatic chuck, thereby dissociating a reactive gas into plasma and etching the wafer.

[0053] The technical means of the present invention will be introduced below through two preferred embodiments.

[0054] Example 1 As shown in FIG. 14 , this embodiment provides an electrostatic chuck, which includes a base 110 and a dielectric plate 130 mounted on the base 110. The dielectric plate 130 is connected to the base 110 via an adhesive layer 120. To adjust the temperature of a wafer (not shown), the base is provided with a first through-hole 111, and the dielectric plate 130 is provided with a second through-hole 131 axially penetrating the dielectric plate 130. The second through-hole 131 communicates with the first through-hole 111. Cooling gas passes through the first through-hole 111 and the second through-hole 131 in order to contact the back surface of the wafer fixed to the dielectric plate 130, thereby adjusting and controlling the wafer temperature. In this embodiment, the cooling gas is helium gas.

[0055] A porous plug assembly 600 is provided in the first through-hole 111. The porous plug assembly 600 includes a porous plug body 610 having a porous structure and an insulating dense layer 620. The porosity of the porous plug body 610 is 50%, and gas enters the porous plug body 610 from a bottom surface 611, passes through the porous plug body 610, and exits from a top surface 612 of the porous plug body 610. The dense layer 620 is made of a ceramic material with a porosity smaller than that of the porous plug body 610. The dense layer 620 includes a side portion 621 and a lateral portion 622. The lateral portion 622 extends inward and outward simultaneously. An upper surface of the lateral portion 622 is substantially flush with a tip 6211 of the lateral portion 621, and a lower surface of the lateral portion 622 is substantially flush with the top surface 612.

[0056] The lateral portion 622 includes an outwardly extending first unit 6221 and an inwardly extending second unit 6222. The second unit 6222 covers a portion of the top surface 612, and gas flows out from the area of ​​the top surface 612 that is not covered by the second unit 6222.

[0057] The adhesive layer 120 has a stepped shape and is made up of a first adhesive layer 1201 and a second adhesive layer 1202 that are connected to each other. The first adhesive layer 1201 is provided between the lower surface of the dielectric plate 130 and the base 110, and adheres the dielectric plate 130 to the base 110. The extended first units 6221 occupy the filling space of the first adhesive layer 1201, and the first adhesive layer 1201 is separated from the area where the porous plug assembly 600 comes into contact with plasma, making it difficult for the plasma to corrode the adhesive layer 120. The second adhesive layer 1202 is provided between the lower surface of the first units 6221 and the base 110. The dielectric plate 130 is pressed axially to connect the dielectric plate 130 to the base 110, and the first unit 6221 is pressed downward together with the dielectric plate 130 to push out the second adhesive layer 1202, and the soft second adhesive layer 1202 provides compensation for the slit between the lateral portion 622 and the dielectric plate 130, making the slit within 0.1 mm.

[0058] The adhesive layer 120 may further include a third adhesive layer 1203 provided between the side portion 621 and the base 110. The third adhesive layer 1203 communicates with the second adhesive layer 1202, and the adhesive layer 120 is formed as a continuous overall structure. In other embodiments, the third adhesive layer 1203 may not be provided. An insulating layer 140 is further provided between the adhesive layer 120 and the base 110, and the insulating layer 140 is made of alumina.

[0059] The outwardly extending first unit 6221 overlaps with the adhesive layer 120 and the alumina insulating layer, significantly improving breakdown resistance voltage and providing excellent breakdown resistance even when defects exist in the adhesive layer 120 or the alumina insulating layer. Compared to the prior art, the discharge space between the dielectric plate 130 and the porous plug assembly 600 is relatively small, which is unfavorable for arc discharge. The lateral portion 622 effectively protects the adhesive layer 120 and reduces the risk of the adhesive layer 120 being corroded by plasma. Furthermore, the lateral portion also allows the adhesive layer 120 to penetrate into the top surface of the porous plug body 610, preventing clogging of the pores in the porous plug body 610.

[0060] Example 2 15 , the electrostatic chuck according to this embodiment is substantially the same as that of Example 1. In this embodiment, the lateral portions 622 extend inward and outward simultaneously, the upper surfaces of the lateral portions 622 are substantially flush with the tips 6211 of the side portions 621, the lower surfaces 612 of the lateral portions 622 are lower than the top surfaces, and the area of ​​the top surfaces 612 is smaller than the bottom surfaces 611, and the porous plug body 610 is substantially convex.

[0061] The dielectric plate 130 may extend above the top surface 612, with a gap 6120 between the bottom surface of the dielectric plate 130 and the top surface 612. The dielectric plate 130 may not contact the top surface 612, reducing the obstruction to the outflow of gas.

[0062] In this embodiment, an elastic member 630 is installed at the bottom end of the lateral portion 621, and the elastic member 630, together with the second adhesive layer 1202, can provide compensation for the slit between the dielectric plate 130 and the lateral portion 622.

[0063] In view of the above, the present invention provides a porous plug assembly, an electrostatic chuck, and a plasma etching apparatus. The porous plug assembly includes a porous plug body having a porous structure and an insulating dense layer. The dense layer has side portions formed on side walls of the porous plug body and lateral portions formed at the ends of the side portions and extending in a substantially horizontal direction. The extended lateral portions extend the distance between the adhesive layer of the electrostatic chuck and the plasma, thereby reducing the risk of the adhesive layer being corroded by the plasma and improving the corrosion resistance of the electrostatic chuck. The porous plug assembly further reduces the discharge space and reduces the risk of arcing. The porous plug assembly effectively solves the problem of the adhesive layer clogging the porous plug body.

[0064] Although the present invention has been described in detail through the above preferred embodiments, the above description should not be construed as a limitation on the present invention. After reading the above content, various modifications and alternatives to the present invention will be obvious to those skilled in the art. Therefore, the scope of protection of the present invention shall be limited to the claims. [Explanation of symbols]

[0065] 100 Electrostatic Chuck 110 base 111 first through hole 112 Passage 120 Adhesive layer 1201 First adhesive layer 1202 Second adhesive layer 1203 Third adhesive layer 121 End face 130 Dielectric plate 131 Second through hole 140 Insulating Layer 200 wafers 300 Plasma 400 Upper electrode 500 Cooling device 600, 700 Porous Plug Assembly 610, 710 Porous plug body 611, 711 bottom 612, 712 top surface 6120 Gap 6121 Slit 620, 720 compact layer 621 Lateral part 6211 Tip 6212-bottom end 622 Horizontal section 630 Elastic member

Claims

1. 1. A porous plug assembly comprising: a porous plug body having a porous structure, the porous plug body including a top surface, a bottom surface, and a sidewall, wherein gas can enter from the bottom surface, pass through the porous plug body, and exit from the top surface; an insulating dense layer including a side portion and a lateral portion, the side portion being provided on a side wall of the porous plug body, the insulating dense layer having a top end and a bottom end, the bottom end being flush with the bottom surface, and the top end not lower than the top surface; the lateral portion extends from a tip of the side portion in at least one direction of a direction away from the porous plug body and a direction approaching the porous plug body, A porous plug assembly, wherein an upper surface of the lateral portion is flush with the tip.

2. the lateral portion extends at least in a direction approaching the porous plug body, The porous plug assembly of claim 1 , wherein a lower surface of the lateral portion is no higher than the top surface.

3. The porous plug assembly of claim 2 , wherein a lower surface of the lateral portion is flush with and partially covers the top surface.

4. The lower surface of the lateral portion is lower than the top surface, The porous plug assembly of claim 2 , wherein the area of ​​the top surface is smaller than the area of ​​the bottom surface.

5. The porous plug assembly according to any one of claims 2 to 4, wherein the lateral portion further extends in a direction away from the porous plug body.

6. The porous plug assembly according to claim 1 , wherein the bottom ends of the side portions are provided with elastic members.

7. 2. The porous plug assembly according to claim 1, wherein the porosity of the porous plug body is 30% to 60%.

8. the porous plug body is a porous ceramic; The porous plug assembly of claim 1 , wherein the dense layer is ceramic.

9. An electrostatic chuck, a base provided with a first through hole, the base having the porous plug assembly according to any one of claims 1 to 8 provided in the first through hole; a dielectric plate provided with an electrode for generating an electrostatic attraction, the dielectric plate having an upper surface used to fix a wafer, a lower surface connected to the base via an adhesive layer, and the lateral portion located between the lower surface of the dielectric plate and the base; a second through-hole penetrating the dielectric plate in the axial direction; The electrostatic chuck, wherein the second through-hole communicates with the first through-hole.

10. the lateral portion extends at least in a direction away from the porous plug body, 10. The electrostatic chuck of claim 9, wherein an adhesive layer is provided between the lower surface of the lateral portion and the base.

11. the upper surface of the base is stepped and has a relatively low first upper surface and a relatively high second upper surface; 11. The electrostatic chuck of claim 10, wherein an adhesive layer is provided between the lower surface of the lateral portion and the first upper surface.

12. 10. The electrostatic chuck of claim 9, wherein an insulating layer is provided between the adhesive layer and the base.

13. 13. The electrostatic chuck of claim 12, wherein the insulating layer is alumina.

14. 10. The electrostatic chuck of claim 9, wherein an adhesive layer is provided between the side portions and the base.

15. A plasma etching apparatus, a reaction chamber, the electrostatic chuck according to any one of claims 9 to 14, an upper electrode, a cooling device, and a high-frequency power supply; the electrostatic chuck is disposed in the reaction chamber, is used to support a wafer, and serves as a lower electrode of the reaction chamber; the cooling device is in communication with the electrostatic chuck and is used to deliver a cooling gas to the wafer; the upper electrode is provided facing the electrostatic chuck, the high frequency power supply is applied to the upper electrode or the electrostatic chuck to generate a high frequency electric field between the upper electrode and the electrostatic chuck, thereby dissociating a reactive gas into plasma and etching the wafer.

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