Electrostatic chuck and method for preparing the same

Abstract

The present invention provides an electrostatic chuck and a preparation method thereof, the electrostatic chuck comprising a base, a heating layer disposed on the base for heating a wafer, and an adsorption layer disposed on the heating layer for adsorbing the wafer, wherein an adhesive layer is disposed between the heating layer and the base, between the heating layer and the adsorption layer, and on the side of the heating layer, and is characterized in that it also comprises a sealing ring made of corrosion-resistant material, the sealing ring is provided with a plurality of through holes penetrating between the inner side and the outer side of the sealing ring, the sealing ring is disposed on the base and surrounds the heating layer, and is used to seal the adhesive layer located on the inner side of the sealing ring. The electrostatic chuck and the preparation method thereof provided by the present invention can significantly reduce the possibility and danger of particle contamination caused by etching of the adhesive layer, thereby improving the stability of the plasma etching process and increasing the yield of chip products.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to an electrostatic chuck and a preparation method thereof. Background Art

[0002] With the rapid innovation and development of modern chip processing technology, chip production capacity continues to increase, while the structure size continues to decrease, which requires strict control of particle contamination falling on the wafer during the plasma etching process of the chip. Because tiny particles larger than 5 nanometers may cause short circuits between different etched grooves or holes, making the chip units on the wafer unusable and scrapped, thereby reducing the product yield.

[0003] Figure 1 is a schematic diagram of the structure of an existing electrostatic chuck. Figure 1 The existing electrostatic chuck includes a base 11 and a heating layer 12 and an adsorption layer 14 which are sequentially arranged on the base 11 from bottom to top, wherein the base 11 is usually made of a metal material such as aluminum alloy, and a radio frequency feed-in is arranged in the base 11 (not shown in the figure). The heating layer 12 is used to heat the wafer 15, and the heating layer 12 usually includes a heat insulation plate, a heating plate and a uniform heating plate which are sequentially arranged from bottom to top. The adsorption layer 14 is usually made of a ceramic material, and an adsorption electrode is arranged in the adsorption layer 14, which is used to fix the wafer 15 on the adsorption layer by electrostatic adsorption. In addition, an adhesive layer 13 is arranged between the heating layer 12 and the base 11, between the heating layer 12 and the adsorption layer 14, and on the side of the heating layer 12, so as to bond and fix the base 11, the heating layer 12 and the adsorption layer 14 together. During use, the electrostatic chuck is usually surrounded by a base ring 16 and a focusing ring 17 arranged on the base ring 16.

[0004] However, during the plasma etching process, the plasma may etch the step surface of the focus ring 17, resulting in a pit A on the step surface. In this case, especially when the thickness of the adsorption layer 14 is relatively thin (about 1 mm), the plasma can easily diffuse through the gap between the adsorption layer 14 and the focus ring 17 to reach the side of the heating layer 12, and etch the adhesive layer 13 covering the side, resulting in the destruction of the adhesive layer 13. The diffusion direction of the plasma is as follows: Figure 1 As shown by the arrow in FIG. After being etched, the bonding layer 13 may diffuse to the surface of the wafer 15 to generate particle contamination, thereby affecting the process stability of the chip plasma etching and reducing the chip product yield. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes an electrostatic chuck and a preparation method thereof, which can significantly reduce the possibility and danger of particle contamination caused by etching of the bonding layer, thereby improving the stability of the plasma etching process and increasing the yield of chip products.

[0006] In order to achieve the purpose of the present invention, an electrostatic chuck is provided, comprising a base, a heating layer arranged on the base for heating a wafer, and an adsorption layer arranged on the heating layer for adsorbing the wafer, wherein an adhesive layer is arranged between the heating layer and the base, between the heating layer and the adsorption layer, and on the side of the heating layer, and further comprising a sealing ring made of corrosion-resistant material, wherein the sealing ring is provided with a plurality of through holes extending between the inner side and the outer side of the sealing ring, the sealing ring is arranged on the base and surrounds the heating layer, and is used to seal the adhesive layer located on the inner side of the sealing ring.

[0007] Optionally, each of the through holes comprises a tapered hole, one end opening of the tapered hole is located on the inner side of the sealing ring, and the other end opening extends toward the outer side of the sealing ring, and the diameter of the tapered hole decreases from the inner side to the outer side of the sealing ring.

[0008] Optionally, each of the through holes further comprises a straight through hole, one end of which is connected to the end of the tapered hole with the smallest opening diameter, and the other end extends to the outer surface of the sealing ring, and the diameter of the straight through hole is equal to the minimum diameter of the tapered hole.

[0009] Optionally, the opening diameter of the tapered hole on the outer side of the sealing ring is less than or equal to 3 mm; the opening diameter of the tapered hole on the inner side of the sealing ring is less than or equal to 15 mm;

[0010] The axial depth of the straight through hole is half of the axial depth of the through hole.

[0011] Optionally, the electrostatic chuck further comprises a protective ring made of corrosion-resistant material, wherein the protective ring is disposed on the base and surrounds the sealing ring, and the protective ring covers the side surfaces of the sealing ring, the side surfaces of the adsorption layer and at least part of the side surfaces of the base.

[0012] Optionally, the protection ring is a film layer formed on the side surface of the sealing ring, the side surface of the adsorption layer and at least part of the side surface of the base by spraying or deposition.

[0013] Optionally, the corrosion-resistant material includes ceramic material or ceramic-based composite material.

[0014] Optionally, the ceramic material includes Al 2 O3 , Y 2 O 3 , Y 3 Al 5 O 12 , YF 3 , YOF, ZrO 2 , Er 2 O 3 and SiC.

[0015] Optionally, the ceramic matrix composite material is Al 2 O 3 , Y 2 O 3 , Y 3 Al 5 O 12 , YF 3 , YOF, ZrO 2 , Er 2 O 3 A composite ceramic based on at least one of Si and SiC.

[0016] Optionally, the corrosion-resistant material includes metal.

[0017] Optionally, the sealing ring and the base are integrally formed.

[0018] Optionally, an edge area of ​​the base for supporting the sealing ring is lower than a central area of ​​the base for supporting the heating layer.

[0019] As another technical solution, the present invention further provides a method for preparing an electrostatic chuck, and the electrostatic chuck provided by the present invention is prepared. The preparation method comprises:

[0020] coating an adhesive material on the upper surface of the base;

[0021] placing the heating layer on the base coated with the bonding material;

[0022] Placing the sealing ring on the base and surrounding the heating layer;

[0023] Adding bonding material to the upper surface of the heating layer until the bonding material covers the upper surface of the heating layer and fills the gap between the side surface of the heating layer and the inner side surface of the sealing ring;

[0024] placing the adsorption layer on the heating layer coated with the bonding material;

[0025] Performing a hot pressing process to bond the base, the heating layer and the adsorption layer together through the bonding material, and allowing the bonding material to form the bonding layer;

[0026] Wherein, the maximum thermal pressure used in the hot pressing process is less than or equal to 70% of the yield strength or fracture strength of the sealing ring.

[0027] The present invention has the following beneficial effects:

[0028] In the technical solution of the electrostatic chuck and the preparation method thereof provided by the present invention, by adding a sealing ring with a corrosion-resistant material on the base, the sealing ring surrounds the heating layer and is used to seal the bonding layer located on the inner side of the sealing ring, so that the bonding layer can be prevented from being etched by plasma. At the same time, since the sealing ring has a corrosion-resistant material, its plasma etching resistance is stable, so that the possibility and danger of particle contamination can be significantly reduced, thereby improving the stability of the plasma etching process and improving the chip product yield. At the same time, the sealing ring is provided with a plurality of through holes penetrating between the inner side and the outer side of the sealing ring. When the hot pressing process is carried out, the above-mentioned through holes are conducive to the flow of the bonding material during the hot pressing deformation, so that the excess bonding material squeezed out can be discharged to the outside of the sealing ring through the through holes, so that the bonding layer formed after the hot pressing process is completed can meet the precision requirements of parameters such as thickness and flatness, thereby ensuring the production quality of the electrostatic chuck. In addition, the above-mentioned sealing ring can also increase the service life of the electrostatic chuck, extend the service life of the electrostatic chuck, thereby reducing the production cost and improving the production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of an existing electrostatic chuck;

[0030] Figure 2 A cross-sectional view of an electrostatic chuck provided in accordance with a first embodiment of the present invention;

[0031] Figure 3A A three-dimensional diagram of a sealing ring used in a first embodiment of the present invention;

[0032] Figure 3B An axial cross-sectional view of a sealing ring used in a first embodiment of the present invention;

[0033] Figure 3C for Figure 3B Enlarged view of the middle I area;

[0034] Figure 4 A cross-sectional view of an electrostatic chuck provided in accordance with a second embodiment of the present invention;

[0035] Figure 5 A cross-sectional view of an electrostatic chuck provided in accordance with a third embodiment of the present invention;

[0036] Figure 6 A cross-sectional view of an electrostatic chuck provided in accordance with a fourth embodiment of the present invention;

[0037] Figure 7 A flowchart of a method for preparing an electrostatic chuck provided in a fifth embodiment of the present invention;

[0038] Fig. 8A A process diagram of steps S1 to S3 of a method for preparing an electrostatic chuck provided in a fifth embodiment of the present invention;

[0039] Figure 8B This is a process diagram of steps S4 to S6 of a method for preparing an electrostatic chuck provided in a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solution of the present invention, the electrostatic chuck and the preparation method thereof provided by the present invention are described in detail below with reference to the accompanying drawings.

[0041] First embodiment

[0042] See also Figure 2 The electrostatic chuck provided in this embodiment includes a base 11, a heating layer 12 disposed on the base 11 for heating a wafer 15, and an adsorption layer 14 disposed on the heating layer 12 for adsorbing the wafer 15, wherein the base 11 is usually made of a metal material such as aluminum alloy, and optionally, a radio frequency feed-in (not shown in the figure) is disposed in the base 11, which is used to be electrically connected to a radio frequency power source so as to be able to feed radio frequency power. The heating layer 12, for example, includes a heat insulation plate (or heat insulation layer), a heating plate (or heater), and a uniform heating plate (or uniform heating layer) disposed sequentially from bottom to top. Of course, in practical applications, the specific structure of the heating layer 12 is not limited thereto, as long as the wafer 15 can be heated. The adsorption layer 14 is usually made of an insulating material such as ceramic, and an adsorption electrode (not shown in the figure) is disposed in the adsorption layer 14, which is used to fix the wafer 15 on the adsorption layer 14 by electrostatic adsorption.

[0043] The above-mentioned bonding layer 13 is arranged between the heating layer 12 and the base 11, between the heating layer 12 and the adsorption layer 14, and on the side of the heating layer 12. Figure 2 As shown, the bonding layer 13 can cover the heating layer 12 therein, and bond the base 11, the heating layer 12 and the adsorption layer 14 together. In practical applications, bonding layers are also provided between the heat insulation board (or heat insulation layer) and the heating board (or heater) in the heating layer 12, and between the heating board (or heater) and the uniform heating board (or uniform heating layer), so as to achieve bonding and fixing of the heat insulation board (or heat insulation layer), the heating board (or heater) and the uniform heating board (or uniform heating layer).

[0044] In some optional embodiments, the thickness of the bonding layer 13 may be greater than or equal to 0.05 mm and less than or equal to 0.5 mm. Preferably, the thickness of the bonding layer 13 may be greater than or equal to 0.1 mm and less than or equal to 0.2 mm.

[0045] On this basis, the electrostatic chuck further includes a sealing ring 21 made of corrosion-resistant material. The sealing ring 21 is disposed on the base 11 and surrounds the heating layer 12 to seal the adhesive layer 13 located inside the sealing ring 21 .

[0046] In some optional embodiments, the corrosion-resistant material includes a ceramic material or a ceramic-based composite material, which has stable plasma etching resistance and is far superior to the plasma etching resistance of bonding materials and the like.

[0047] In some optional embodiments, the ceramic material includes Al 2 O 3 , Y 2 O 3 , YF 3 , YOF, ZrO 2 , Er 2 O 3 and SiC.

[0048] In some optional embodiments, the ceramic matrix composite material may be, for example, Al 2 O 3 , Y 2 O 3 , YF 3 , YOF, ZrO 2 , Er 2 O 3 A composite ceramic based on at least one of Si and SiC.

[0049] In some optional embodiments, an axial gap 22 is provided between the upper surface of the sealing ring 21 and the lower surface of the adsorption layer 14. The axial gap 22 can avoid repeated positioning or even damage to the adsorption layer 14 due to direct contact, thereby preventing the adsorption layer 14 from being inaccurately positioned, unstablely positioned, or having positioning interference.

[0050] In some optional embodiments, the axial dimension of the axial gap 22 is greater than or equal to 0.05 mm and less than or equal to 0.5 mm. Preferably, the thickness of the bonding layer 13 may be greater than or equal to 0.1 mm and less than or equal to 0.2 mm. By limiting the axial dimension of the axial gap 22 to this numerical range, it is possible to prevent plasma from entering the inner side of the sealing ring 21 from the axial gap 22 to etch the bonding layer 13.

[0051] The electrostatic chuck provided in this embodiment can prevent the bonding layer 113 from being etched by plasma by means of the sealing ring 21. At the same time, since the sealing ring 21 is made of corrosion-resistant material, its plasma etching resistance is stable, which can significantly reduce the possibility and danger of particle contamination caused by etching of the bonding layer 13, thereby improving the stability of the plasma etching process and increasing the chip product yield. In addition, the sealing ring 21 can also increase the service life of the electrostatic chuck, extend the service life of the electrostatic chuck, thereby reducing production costs and improving production efficiency.

[0052] Moreover, if Figure 3A and Figure 3B As shown, the sealing ring 21 is provided with a plurality of through holes 211 penetrating between the inner side surface and the outer side surface of the sealing ring 21 .

[0053] In the process of preparing the electrostatic chuck, a hot pressing process is required to bond the heating layer 12 and the adsorption layer 14 to the base 11 through an adhesive material. Specifically, the adhesive material is coated between the heating layer 12 and the base 11, between the heating layer 12 and the adsorption layer 14, and on the side of the heating layer 12. During the hot pressing process, the adhesive material will soften under heating and is easy to flow and deform, and finally achieve sufficient welding with the contact surface (including the surface in contact with the base 11, the heating layer 12 and the adsorption layer 14) under the action of pressure.

[0054] During the hot pressing process, the through hole 211 is used to facilitate the flow of the adhesive material during hot pressing deformation, so that the excess adhesive material squeezed out can be discharged to the outside of the sealing ring 21 through the through hole 211, thereby ensuring that the adhesive layer 13 formed after the hot pressing process is completed can meet the precision requirements of parameters such as thickness and flatness, thereby ensuring the production quality of the electrostatic chuck.

[0055] It should be noted that before the above-mentioned hot pressing process is performed, the upper surface of the base 11 is first coated with an adhesive material; then the heating layer 12 is placed on the base 11 coated with the adhesive material; then the sealing ring 21 is placed on the base 11 and surrounds the heating layer 12, and then the adhesive material is added to the upper surface of the heating layer 12 until the adhesive material covers the upper surface of the heating layer 12 and fills the gap between the side of the heating layer 12 and the inner side of the sealing ring 21. In this way, the upper surface of the base 11, the upper surface and the side of the heating layer 12 are all covered with adhesive material.

[0056] In some optional embodiments, such as Figure 3A and Figure 3B As shown, there are multiple through holes 211, which are evenly distributed along the circumference of the sealing ring 21. However, the present invention is not limited thereto, and in practical applications, a suitable through hole arrangement can be selected according to specific needs.

[0057] In some optional embodiments, the number of the through holes 211 is greater than or equal to 5 and less than or equal to 100.

[0058] In some optional embodiments, such as Figure 3C As shown, each through hole 211 includes a tapered hole 211a and a straight hole 211b, wherein one end of the tapered hole 211a opens on the inner side of the sealing ring 21, and the other end opens to extend to the outer side of the sealing ring 21, and the diameter of the tapered hole 211a decreases from the inner side to the outer side of the sealing ring 21; one end of the straight hole 211b is connected to the end with the smallest opening diameter of the tapered hole 211a, and the other end extends to the outer side of the sealing ring 21, and the diameter of the straight hole 211b is equal to the smallest diameter of the tapered hole 211a. With the help of the tapered hole 211a, the excess adhesive material squeezed out during the hot pressing process can more easily enter the through hole 211 and be discharged from the outer side of the sealing ring 21, so as to release the stress generated by the different thicknesses of the adhesive material at different positions during hot pressing deformation, so that the thickness of the adhesive layer 13 finally formed can be uniform and the structure can be stable. At the same time, by using the through hole 211 b having a smaller diameter than the tapered hole 211 a , the risk of particle contamination caused by corrosion of the bonding material in the through hole 211 b during the process can be reduced.

[0059] In a specific embodiment, the opening diameter D1 of the tapered hole 211a on the outer side facing the sealing ring 21 is less than or equal to 3 mm; the opening diameter D2 of the tapered hole 211a on the inner side of the sealing ring 21 is less than or equal to 15 mm; the axial depth L1 of the straight hole 211b is half of the axial depth of the through hole 211 (i.e., the radial thickness L of the sealing ring 21). The radial thickness L of the sealing ring 21 is less than or equal to 10 mm, preferably less than or equal to 5 mm.

[0060] In some other optional embodiments, each through hole 211 may also include a tapered hole, that is, no straight through hole is provided, and one end opening of the tapered hole 211a is located on the inner side surface of the sealing ring 21, and the other end opening extends toward the outer side surface of the sealing ring 21 to the outer side surface of the sealing ring 21, that is, the end with the smallest opening diameter of the tapered hole 211a is located on the outer side surface of the sealing ring 21, which can also make it easier for excess adhesive material squeezed out during the hot pressing process to enter the through hole 211, while reducing the risk of particle contamination caused by corrosion of the adhesive material in the straight through hole 211b during the process.

[0061] In some optional embodiments, such as Figure 3C As shown, according to the hot pressing temperature and the thermal fluidity of the bonding material, the position of the through hole 211 in the axial direction of the sealing ring 21 can be located in the middle of the sealing ring 21 in the axial direction or slightly higher than the middle.

[0062] In practical applications, the structural dimensions of the sealing ring 21, such as the axial height and radial thickness, and the structure, dimensions and arrangement of the through holes 211, can be determined according to the structural design of other components of the electrostatic chuck. For example, the axial height of the sealing ring 21 is determined by the total axial height of the heating layer 12 and the bonding layer 13.

[0063] Second embodiment

[0064] The electrostatic chuck provided in this embodiment is an improvement made on the basis of the above-mentioned first embodiment. Specifically, Figure 4 As shown, the electrostatic chuck also includes a protective ring 23 made of corrosion-resistant material, which is arranged on the base 11 and surrounds the sealing ring 21, and the protective ring 23 covers the side of the sealing ring 21, the side of the adsorption layer 14 and at least part of the side of the base 11. Specifically, the base 11 has a boss, and the protective ring 23 covers the side of the boss of the base 11, the side of the sealing ring 21 and the side of the adsorption layer 14 from bottom to top. With the help of the protective ring 23, combined with the sealing ring 21, the particle contamination that may be caused by the adhesive layer on the side of the heating layer 12 can be completely eliminated.

[0065] In some optional embodiments, the corrosion-resistant material includes a ceramic material or a ceramic-based composite material, which has stable plasma etching resistance and is far superior to the plasma etching resistance of bonding materials and the like.

[0066] In some optional embodiments, the ceramic material includes Al 2 O 3 , Y 2 O 3 , Y 3 Al 5 O 12 , YF 3 , YOF, ZrO 2 , Er 2 O 3 and SiC.

[0067] In some optional embodiments, the ceramic matrix composite material may be, for example, Al 2 O 3 , Y 2 O 3 , Y 3 Al 5 O 12 , YF 3 , YOF, ZrO 2 , Er 2 O 3 A composite ceramic based on at least one of Si and SiC.

[0068] In some optional embodiments, the protection ring 23 may be a film layer (or coating) formed by spraying or deposition on the side of the sealing ring 21, the side of the adsorption layer 14 and at least part of the side of the base 11. Specific preparation methods include, but are not limited to: plasma spraying, physical vapor deposition (PVD), chemical vapor deposition (CVD), physical chemical vapor deposition (PCVD), plasma enhanced physical vapor deposition (PEPVD), plasma enhanced chemical vapor deposition (PECVD), ion beam enhanced deposition (IAD), etc.

[0069] Third embodiment

[0070] The electrostatic chuck provided in this embodiment is an improvement made on the basis of one of the first and second embodiments above. Specifically, Figure 5 As shown, the edge region 111 of the base 11 for supporting the sealing ring 21 ′ is lower than the central region 112 of the base 11 for supporting the heating layer 12 .

[0071] The edge area 111 and the center area 112 form an annular step, which not only facilitates the installation and positioning of the sealing ring 21 ′, but also increases the axial height relative to the sealing ring 21 in the aforementioned embodiment. The increase in size is beneficial to the processing and installation of the sealing ring.

[0072] Fourth embodiment

[0073] The electrostatic chuck provided in this embodiment is an improvement made on the basis of one of the first, second and third embodiments above. Specifically, Figure 6 As shown, the corrosion-resistant material of the sealing ring 21 ″ includes metal. The plasma etching resistance of the metal is also relatively stable, which is far superior to the plasma etching resistance of the bonding material and the like. The metal is, for example, an aluminum alloy.

[0074] In some optional embodiments, the sealing ring 21 ″ is integrally formed with the base 11 . In this way, not only can the installation steps of the sealing ring 21 ″ be saved and the preparation process of the electrostatic chuck be simplified, but also the cost can be reduced.

[0075] Fifth embodiment

[0076] As another technical solution, please also refer to Figure 7 and Fig. 8A , Figure 8B This embodiment provides a method for preparing an electrostatic chuck, which is used to prepare the electrostatic chuck provided in one of the first, second, third, and fourth embodiments, to prepare Figure 2 Taking the electrostatic chuck shown in the figure as an example, the preparation method includes:

[0077] S1, coating the adhesive material 13a on the upper surface of the base 11, such as Fig. 8A As shown in (A);

[0078] S2, placing the heating layer 12 on the base 11 coated with the above-mentioned adhesive material 13a, such as Fig. 8A As shown in (B);

[0079] S3, placing the sealing ring 21 on the base 11 and surrounding the heating layer 12, as shown in FIG. Fig. 8A As shown in (C);

[0080] S4, adding adhesive material 13b to the upper surface of the heating layer 12 until the adhesive material 13b covers the upper surface of the heating layer 12 and fills the gap between the side surface of the heating layer 12 and the inner side surface of the sealing ring 21, as shown in FIG. Figure 8B As shown in (D);

[0081] S5, placing the adsorption layer 14 on the heating layer 12 coated with the above-mentioned adhesive material 13b, such as Figure 8B As shown in (E);

[0082] S6, performing a hot pressing process to bond the base 11, the heating layer 12 and the adsorption layer 14 together through the above-mentioned bonding materials 13a and 13b, and making the above-mentioned bonding materials form a bonding layer 13, such as Figure 8B As shown in (F) in .

[0083] During the hot pressing process, the bonding materials 13a and 13b will become soft and easy to flow and deform under the heating state, and finally achieve full welding with the contact surface (including the surface in contact with the base 11, the heating layer 12 and the adsorption layer 14) under the action of pressure. In this way, the base 11, the heating layer 12 and the adsorption layer 14 can be bonded and fixed together. The electrostatic chuck formed after completing step S6 is as follows Figure 2 shown.

[0084] In some optional embodiments, the maximum heat pressure used in the above-mentioned hot pressing process is less than or equal to 70% of the yield strength (if the sealing ring 21 is made of a deformable plastic material) or the fracture strength (if the sealing ring 21 is made of a brittle material that cannot be plastically deformed) of the sealing ring 21. In this way, it can be ensured that the adhesive layer 13 coated with the heating layer 12 formed by the hot pressing process will not damage the sealing ring 21.

[0085] In some optional embodiments, the heating temperature used in the hot pressing process is 100° C.-130° C., and the heating temperature depends on the type of bonding material and the functional requirements for the electrostatic chuck.

[0086] In addition, it is necessary to control the thermal pressure and its distribution used in the hot pressing process to ensure that the base 11, the heating layer 12 and the adsorption layer 14 maintain good flatness and parallelism, so as to facilitate the flatness and parallelism of the upper surface of the adsorption layer 14 formed after the final grinding to meet the design requirements of the electrostatic chuck.

[0087] In summary, in the technical solution of the electrostatic chuck and its preparation method provided by the present invention, by adding a sealing ring with corrosion-resistant material on the base, the sealing ring surrounds the heating layer and is used to seal the bonding layer located on the inner side of the sealing ring, the bonding layer can be prevented from being etched by plasma. At the same time, since the sealing ring has a corrosion-resistant material, its plasma etching resistance is stable, which can significantly reduce the possibility and danger of particle contamination, thereby improving the stability of the plasma etching process and improving the chip product yield. At the same time, the sealing ring is provided with a plurality of through holes penetrating between the inner side and the outer side of the sealing ring. When the hot pressing process is carried out, with the help of the above-mentioned through holes, it is conducive to the flow of the bonding material during hot pressing deformation, so that the excess bonding material squeezed out can be discharged to the outside of the sealing ring through the through holes, thereby ensuring that the bonding layer formed after the hot pressing process is completed can meet the precision requirements of parameters such as thickness and flatness, thereby ensuring the production quality of the electrostatic chuck. In addition, with the help of the above-mentioned sealing ring, the service life of the electrostatic chuck can be increased, the service life of the electrostatic chuck can be extended, thereby reducing the production cost and improving the production efficiency.

[0088] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill 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, comprising a base, a heating layer disposed on the base for heating a wafer, and an adsorption layer disposed on the heating layer for adsorbing the wafer, in, An adhesive layer is arranged between the heating layer and the base, between the heating layer and the adsorption layer, and on the side of the heating layer, and is characterized in that it also includes a sealing ring made of corrosion-resistant material, and the sealing ring is provided with a plurality of through holes penetrating between the inner side and the outer side of the sealing ring, and the through holes allow the adhesive material of the adhesive layer to pass through under hot pressing. The sealing ring is arranged on the base and surrounds the heating layer, and is used to seal the adhesive layer located on the inner side of the sealing ring.

2. The electrostatic chuck according to claim 1, It is characterized in that Each through hole comprises a tapered hole, one end opening of the tapered hole is located on the inner side of the sealing ring, and the other end opening extends to the outer side of the sealing ring, and the diameter of the tapered hole decreases from the inner side to the outer side of the sealing ring.

3. The electrostatic chuck according to claim 2, It is characterized in that Each of the through holes also includes a straight through hole, one end of which is connected to the end of the tapered hole with the smallest opening diameter, and the other end extends to the outer surface of the sealing ring. The diameter of the straight through hole is equal to the minimum diameter of the tapered hole.

4. The electrostatic chuck according to claim 3, It is characterized in that The opening diameter of the tapered hole on the outer side of the sealing ring is less than or equal to 3 mm; the opening diameter of the tapered hole on the inner side of the sealing ring is less than or equal to 15 mm; The axial depth of the straight through hole is half of the axial depth of the through hole.

5. The electrostatic chuck according to claim 1, It is characterized in that The electrostatic chuck also includes a protection ring made of corrosion-resistant material, which is arranged on the base and surrounds the sealing ring. The protection ring covers the side of the sealing ring, the side of the adsorption layer and at least part of the side of the base.

6. The electrostatic chuck according to claim 5, It is characterized in that The protection ring is a film layer formed on the side surface of the sealing ring, the side surface of the adsorption layer and at least part of the side surface of the base by spraying or deposition.

7. The electrostatic chuck according to claim 1 or 5, It is characterized in that The corrosion-resistant material includes ceramic material or ceramic-based composite material.

8. The electrostatic chuck according to claim 7, It is characterized in that The ceramic material includes Al 2 O 3 , Y 2 O 3 , Y 3 Al 5 O 12 , YF 3 , YOF, ZrO 2 , Er 2 O 3 and SiC.

9. The electrostatic chuck according to claim 7, It is characterized in that The ceramic matrix composite material is Al 2 O 3 , Y 2 O 3 , Y 3 Al 5 O 12 , YF 3 , YOF, ZrO 2 , Er 2 O 3 A composite ceramic based on at least one of Si and SiC.

10. The electrostatic chuck according to claim 1, It is characterized in that The corrosion-resistant material includes metal.

11. The electrostatic chuck according to claim 10, It is characterized in that The sealing ring is integrally formed with the base.

12. The electrostatic chuck according to claim 1, It is characterized in that An edge region of the base for supporting the sealing ring is lower than a central region of the base for supporting the heating layer.

13. A method for preparing an electrostatic chuck, It is characterized in that Making an electrostatic chuck according to any one of claims 1 to 10 or claim 12, the preparation method comprising: coating an adhesive material on the upper surface of the base; placing the heating layer on the base coated with the bonding material; Placing the sealing ring on the base and surrounding the heating layer; Adding bonding material to the upper surface of the heating layer until the bonding material covers the upper surface of the heating layer and fills the gap between the side surface of the heating layer and the inner side surface of the sealing ring; placing the adsorption layer on the heating layer coated with the bonding material; Performing a hot pressing process to bond the base, the heating layer and the adsorption layer together through the bonding material, and allowing the bonding material to form the bonding layer; Wherein, the maximum thermal pressure used in the hot pressing process is less than or equal to 70% of the yield strength or fracture strength of the sealing ring.

Images