Internal heating type electrostatic chuck convenient to produce and uniform in heating and preparation method of internal heating type electrostatic chuck

Abstract

The invention discloses an internal heating type electrostatic chuck convenient to produce and uniform in heating and a preparation method of the internal heating type electrostatic chuck. A ceramic body of the electrostatic chuck comprises a ceramic layer, an adsorption electrode layer, a heating electrode layer and a glass layer. The ceramic layer and the adsorption electrode layer are prepared through a co-firing technology, the adsorption electrode layer is formed in the ceramic layer, the heating electrode layer and the glass layer are sequentially prepared on the lower surface of the ceramic layer in a printing and sintering mode, and the heating electrode layer is located between the ceramic layer and the glass layer. The preparation method comprises the following steps: S1, preparing a raw ceramic tape through a slurry preparation and tape casting process; s2, obtaining a ceramic layer and an adsorption electrode layer in the ceramic layer by adopting a multi-layer co-fired ceramic technology; and S3, sequentially preparing the heating electrode layer and the glass layer on the lower surface of the ceramic layer in a printing and sintering manner to obtain the ceramic body of the electrostatic chuck. The method has the advantages of being high in yield, easy to operate and low in cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to an inner heating electrostatic chuck with uniform heating and a preparation method thereof. BACKGROUND

[0002] In recent years, the semiconductor industry has developed rapidly, and in its manufacturing process, semiconductor components are increasingly highly integrated and high-performance. As an indispensable clamping component for wafer processing in semiconductor manufacturing, the demand for electrostatic chucks has increased dramatically.

[0003] To meet the demand for precise temperature control in modern semiconductor manufacturing processes, electrostatic chucks need to integrate heating functions, and temperature directly determines the yield, precision, and consistency of wafer processing. The heating function of an electrostatic chuck can be achieved through two methods: internal heating and external heating. In the former, the heating element is completely embedded in the ceramic body of the electrostatic chuck, and in the latter, the heating element is generally attached between the ceramic body and the base. Compared with external heating electrostatic chucks, internal heating electrostatic chucks have the advantages of short heat conduction path, fast temperature control response, and good temperature uniformity. However, due to the process of embedding the heating element in the ceramic body, there are disadvantages such as difficulty in sintering the ceramic body and low yield.

[0004] The ceramic body of the electrostatic chuck has integrated conductive circuits inside, and the ceramic body is often manufactured through multi-layer co-sintering ceramic technology. The typical process of multi-layer co-sintering ceramic technology includes slurry preparation, tape casting, green ceramic tape processing, via filling, internal electrode printing, lamination, isostatic pressing, machining, de-binding sintering, and soldering external electrodes. Among them, the quality of the green ceramic sheet prepared by tape casting is crucial. The green ceramic sheet, as the core substrate of multi-layer co-sintering ceramic technology, directly determines the feasibility of subsequent processes, the stability of the co-sintering process, and affects the performance and yield of the final product. One important quality indicator of the green ceramic sheet is thickness uniformity, which directly affects the thickness uniformity of the electrodes printed on the green ceramic sheet. Uneven electrode thickness results in inconsistent resistance and heating power at different locations, affecting temperature uniformity. In the process of green ceramic sheet lamination and isostatic pressing, different pressures are applied to thick and thin parts, which can cause poor interlayer bonding of the green ceramic sheet, resulting in defects such as delamination and bulging during the subsequent de-binding process, reducing the yield.

[0005] In addition to including the adsorption electrode, the inner heating type electrostatic chuck ceramic body is also designed with a heating electrode, and a large number of green ceramic sheets are required during lamination. The more the number of lamination layers, the more obvious the thickness difference of each part of the green body due to error accumulation, the greater the possibility of local poor bonding between the green ceramic sheet layers, the more difficult to guarantee the quality of the green body, and the higher the defective rate of the fired product. If the defective rate needs to be reduced, the standard of the green ceramic sheet needs to be improved under the condition that the number of lamination layers remains unchanged, such as the thickness uniformity requirement may need to be improved from ± 2% to ± 1% to obtain a green body with high quality and good interlayer bonding, but this significantly increases the production cost. In view of this, a new electrostatic chuck manufacturing process is designed to solve the above problems. SUMMARY

[0006] Therefore, the present application aims at the defects of the prior art, and the main purpose is to provide an inner heating type electrostatic chuck which is convenient to produce and has uniform heating, and a preparation method thereof, which has the advantages of high yield, simple operation and low cost.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions: An inner heating type electrostatic chuck which is convenient to produce and has uniform heating, the ceramic body of the electrostatic chuck comprises a ceramic layer, an adsorption electrode layer, a heating electrode layer and a glass layer; the ceramic layer and the adsorption electrode layer are prepared by co-firing technology, the adsorption electrode layer is formed in the ceramic layer, and the heating electrode layer and the glass layer are prepared on the lower surface of the ceramic layer in turn by printing and sintering, and the heating electrode layer is located between the ceramic layer and the glass layer.

[0008] As a preferred solution, the electrostatic chuck further comprises a metal base and a bonding material layer, the metal base is made of metal or alloy, the bonding material layer is made of silicone or elastic polymer, and the bonding material layer is combined and fixed on the upper surface of the metal base and located below the lower surface of the glass layer.

[0009] A preparation method of the inner heating type electrostatic chuck as described in any one of the preceding solutions, comprising the following steps: S1: preparing a green ceramic tape by slurry preparation and tape casting process; S2: obtaining the ceramic layer and the adsorption electrode layer in the ceramic layer by multi-layer co-firing ceramic technology; The process of the multi-layer co-firing ceramic technology comprises: first cutting, punching, screen printing and / or filling holes, and laminating and pressing the green ceramic tape to form a green ceramic body; then machining, degreasing and sintering the green body to form a ceramic body; S3: preparing the heating electrode layer and the glass layer on the lower surface of the ceramic layer in turn by printing and sintering to obtain the ceramic body of the electrostatic chuck.

[0010] As a preferred solution, the following steps are further included: S4: soldering the electrode post into the electrode hole of the ceramic body, and finally connecting the ceramic body to the metal base through a bonding process.

[0011] As a preferred solution, the slurry in step S1 comprises ceramic aggregate, sintering aid, and contains or does not contain resistance control agent; The ceramic aggregate is alumina or aluminum nitride. The resistance control agent is at least one of titanium oxide, titanium nitride, titanium, calcium oxide, vanadium nitride, tantalum nitride, titanium carbide, and molybdenum carbide. The mass ratio of the ceramic aggregate, sintering aid, and resistance control agent is 100: (0.5-5): (1-20).

[0012] As a preferred solution, the conductive slurry used in hole filling and printing in steps S2 and S3 is tungsten-molybdenum metal conductive slurry or ceramic conductive slurry with conductive phase added; and in step S2, the viscosity of the conductive slurry used for hole filling is 20,000-100,000 cp, and in steps S2 and S3, the viscosity of the conductive slurry used for printing is 2,000-10,000 cp.

[0013] As a preferred solution, the glass layer in step S3 is aluminum-silicon glass, quartz glass, zirconium-doped quartz glass, or borosilicate glass.

[0014] As a preferred solution, the aluminum-silicon glass has the following composition: 40-75% silicon dioxide, 15-45% aluminum oxide, 2-6% lithium oxide, 4-7% sodium oxide, 0.5-2% potassium oxide, 1-3% magnesium oxide, and 0.5-2% calcium oxide.

[0015] As a preferred solution, the preparation method of the glass layer in step S3 is as follows: First, avoid the positions of the adsorption electrode hole and the reserved heating electrode hole, and print aluminum-silicon glass slurry on the lower surface of the ceramic layer through silk screen printing; then place it in an oven and dry at 80-150°C for 10-20 min; heat the ceramic layer with the glass layer to 950-1200°C, sinter for 1-3 h, and then naturally cool down; repeat the process of printing aluminum-silicon glass slurry and sintering the glass layer until the thickness of the glass layer reaches 80-150 μm.

[0016] As a preferred solution, the aluminum-silicon glass paste is prepared by fully stirring and mixing an organic carrier, a functional phase and additives, and grinding; the organic carrier includes a solvent butyl carbitol or terpene ester, methyl cellulose or ethyl cellulose, and acrylic resin, accounting for 19-39% of the total mass of the paste; the functional phase is aluminum-silicon glass powder, accounting for 60-80% of the total mass of the paste; and the additives include a thixotropic agent, fumed silica, and a defoaming agent, accounting for 0.1-1% and 0.1-0.5% of the total mass of the paste, respectively.

[0017] Compared with the prior art, the present application has obvious advantages and beneficial effects, and specifically, the above technical solution can know that: Firstly, the ceramic body of the electrostatic chuck is divided into two parts, which are prepared by using the multi-layer co-fired ceramic technology and the printing sintering method, respectively. Specifically, the ceramic layer is prepared by using the multi-layer co-fired ceramic technology, that is, only the adsorption electrode layer is prepared by co-firing. Compared with the conventional method of co-firing the adsorption layer and the heating layer together, the number of co-fired layers is significantly reduced. Since the amount of green ceramic sheet is reduced, the possibility of poor interlayer bonding is reduced, and the defects of delamination and bulging in the subsequent glue removal process are avoided, thereby improving the yield. Since the thickness of the co-fired body is small, the co-firing difficulty is low, and the process complexity is also reduced.

[0018] Secondly, in the present application, the heating electrode layer is prepared on the lower surface of the ceramic layer by printing sintering. Since the ceramic layer has been sintered, the size is stable and accurate after fine grinding of the upper and lower surfaces, and the thickness uniformity of the heating electrode layer and the parallelism relative to the chuck surface can be guaranteed. Compared with the conventional method of printing the heating electrode layer on the green ceramic sheet, the quality problem of uneven thickness of the green ceramic sheet is avoided, which affects the uniformity of the thickness of the heating electrode layer, and finally causes uneven resistance of the electrode at each part, thereby leading to uneven heating temperature. The thickness of the heating electrode layer in the present application is more uniform, the heating power of each part is consistent during work, and uniform heating can be provided to the wafer.

[0019] Thirdly, in the present application, the heating electrode layer is located between the ceramic layer and the glass layer. Since the thermal conductivity of the glass layer is much lower than that of the ceramic layer, only one tenth of the latter, the heat generated by the heating electrode layer is more easily transmitted upward to the wafer, the heating is faster, the temperature rising response time of the wafer is short, and the effective heating efficiency is improved.

[0020] In order to more clearly illustrate the structural features and effects of the present application, the present application will be described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a cross-sectional schematic view of the electrostatic chuck of the preferred embodiment of the present application; Figure 2 is a step diagram of the preparation method of the electrostatic chuck of the preferred embodiment of the present application.

[0022] Brief Description of Drawings 10, metal base; 20, bonding material layer; 30, ceramic body; 31, ceramic layer; 32, adsorption electrode layer; 33, heating electrode layer; 34, glass layer. DETAILED DESCRIPTION

[0023] Please refer to Figure 1 Fig. 1 shows the specific structure of a kind of inner heating electrostatic chuck convenient for production and heating evenly according to the preferred embodiment of the present application, which comprises a metal base 10, a bonding material layer 20 and a ceramic body 30.

[0024] The metal base 10 is made of metal or alloy, and the metal base 10 includes water channels, pin holes, helium gas holes and the like in structure.

[0025] The bonding material layer 20 is fixed on the upper surface of the metal base 10 and located below the lower surface of the glass layer. In this embodiment, the bonding material layer 20 is made of silica gel or elastic polymer, which can effectively alleviate the thermal stress generated in the cold and hot cycle due to the difference in the thermal expansion coefficient between the metal base 10 and the ceramic body 30, and connect and protect the ceramic body 30 between the metal base 10 and the ceramic body 30.

[0026] The ceramic body 30 comprises a ceramic layer 31, an adsorption electrode layer 32, a heating electrode layer 33 and a glass layer 34; the ceramic layer 31 and the adsorption electrode layer 32 are prepared by multi-layer co-firing ceramic technology, the adsorption electrode layer 32 is shaped in the ceramic layer 31, and the heating electrode layer is prepared outside the ceramic body, which reduces the use amount of green ceramic sheet, reduces the possibility of poor interlayer bonding, avoids the defects of delamination and bulging in the subsequent glue removal process due to poor interlayer bonding, improves the yield, and at the same time, due to the small thickness of the co-fired body and low co-firing difficulty, the process complexity is also reduced. The heating electrode layer 33 and the glass layer 34 are prepared on the lower surface of the ceramic layer 31 in turn by printing and sintering, that is, the heating electrode layer 33 is stacked on the lower surface of the ceramic layer 31, the glass layer 34 is stacked on the lower surface of the ceramic layer 31 and the lower surface of the heating electrode layer 33, and the glass layer 34 is located on the upper surface of the bonding material layer 20.

[0027] The heating electrode layer 33 is prepared on the lower surface of the ceramic layer 31 in a printed sintering manner. Since the ceramic layer has been sintered, the size is stable and accurate after fine polishing of the upper and lower surfaces, the thickness uniformity of the heating electrode layer 33 and the parallelism relative to the chuck surface can be guaranteed, the problem of uneven resistance and uneven heating power of the electrode caused by uneven thickness of the heating electrode layer 33 is avoided, and uniform heating of the wafer is realized. Moreover, the heating electrode layer 33 is located between the ceramic layer 31 and the glass layer 34. Since the thermal conductivity of the glass layer 34 is much lower than that of the ceramic layer 31, only one tenth of the latter, the heat generated by the heating electrode layer 33 is more easily transmitted upward to the wafer, the heating is faster, the temperature rising response time of the wafer is short, and the effective heating efficiency is improved.

[0028] As shown in Figure 2 for the foregoing inner heating type electrostatic chuck, a preparation method is provided, comprising the following steps: S1: a green ceramic tape is prepared by slurry preparation and tape casting process; wherein the slurry in the step S1 contains ceramic aggregate, sintering aid, and contains or does not contain resistance control agent; S2: a ceramic layer and an adsorption electrode layer in the ceramic layer are obtained by using multi-layer co-sintering ceramic technology; The process of the multi-layer co-sintering ceramic technology includes: first, the green ceramic tape is cut, punched, screen printed and / or filled, laminated and pressed to form a ceramic green body with an embedded adsorption electrode layer; then the green body is machined, degreased and sintered to form a ceramic body; wherein the conductive slurry used for filling and printing is tungsten-molybdenum metal conductive slurry or ceramic conductive slurry doped with conductive phase, and the viscosity of the conductive slurry used for filling is 20000-100000 cp, and the viscosity of the conductive slurry used for printing is 2000-10000 cp; S3: a heating electrode layer and a glass layer are sequentially prepared on the lower surface of the ceramic layer in a printed sintering manner to obtain a ceramic body of the electrostatic chuck; wherein the glass layer contains aluminum-silicon glass, quartz glass, zirconium-doped quartz glass or boron-silicon glass, the conductive slurry used for printing is tungsten-molybdenum metal conductive slurry or ceramic conductive slurry doped with conductive phase, and the viscosity of the conductive slurry is 2000-10000 cp; S4: the electrode column is brazed into the electrode hole of the ceramic body, and finally the ceramic body is connected to the metal base through the bonding process.

[0029] In this embodiment, the preparation method of the inner heating type electrostatic chuck is specifically described as follows: S1-1: slurry preparation: ceramic aggregate, sintering aid, solvent, dispersant, binder and plasticizer are added into a ball mill, and after sufficient ball milling, a ceramic slurry for tape casting is obtained.

[0030] In this embodiment, the ceramic aggregate can be either alumina or aluminum nitride. Depending on the resistivity requirements of the chuck, a resistance regulator can be added for adjustment. The resistance regulator is at least one of titanium oxide, titanium nitride, titanium, calcium oxide, vanadium nitride, tantalum nitride, titanium carbide, and molybdenum carbide. The mass ratio of ceramic aggregate, sintering aid, and resistance regulator is 100:(0.5-5):(1-20). Taking aluminum nitride as an example, the following embodiment can be used as an example: using yttrium oxide as a sintering aid and titanium nitride as a resistance regulator, 80-100 parts by mass of aluminum nitride powder, 0.5-3 parts of yttrium oxide, and 5-15 parts of titanium nitride are added to a ball mill. The above raw materials, along with 80-200 parts of solvent and 0.1-1.5 parts of dispersant, are added to a ball mill and ball-milled for 4-12 hours. Then, 0.5-8 parts of binder and 0.5-5 parts of plasticizer are added to the ball mill and ball-milled for 1-6 hours to obtain a ceramic slurry.

[0031] S1-2: Casting: The ceramic slurry obtained in step S1-1 is subjected to vacuum degassing treatment for 0.5-3 hours to make the slurry viscosity reach 5000-12000cp; the degassed ceramic slurry is introduced into a casting machine and a green ceramic tape is prepared by casting.

[0032] S2-1: Cutting and punching: Cut the green ceramic strip from step S1 into slices to cut green ceramic pieces of the correct size. The specific size depends on the size of the electrostatic chuck being prepared, such as 540mm×540mm, 360mm×360mm, or 180mm×180mm. The green ceramic pieces are then punched or perforated to form positioning holes, interlayer through holes, and electrode holes.

[0033] S2-2: Hole-filling printing: After cutting and punching, the raw ceramic sheet is screen-printed to fill the interlayer vias with a hole-filling conductive paste. Then, an adsorption electrode layer 32 is printed on the raw ceramic sheet using a printing conductive paste. The conductive paste used for hole filling and printing is either a tungsten-molybdenum metal conductive paste or a ceramic conductive paste doped with a conductive phase. Furthermore, the viscosity of the hole-filling conductive paste is 20,000-100,000 cp, and the viscosity of the printing conductive paste is 2,000-10,000 cp.

[0034] S2-3: Lamination: Referring to the process drawings, the green ceramic sheets after the hole filling printing are placed into the lamination machine in sequence. After dispensing and pre-pressing, a No. 1 ceramic green body (also referred to as the first green body) with a certain bonding strength is obtained; the pre-pressing pressure is 5-20MPa.

[0035] S2-4: Isostatic pressing: The No. 1 ceramic green body is placed in an isostatic press for isostatic pressing to obtain the No. 2 ceramic green body (also referred to as the second green body) with higher bonding strength; the isostatic pressing process adopts the warm isostatic pressing process, with a temperature of 60-100℃, a pressure of 35-100MPa, and a holding time of 5-15min.

[0036] S2-5: Machining: The second ceramic green body from step S2-4 is cut into a circle by machining to obtain the required shape of the ceramic layer 31 of the electrostatic chuck.

[0037] S2-6: Debinding and Sintering: The machined and rounded No. 2 ceramic green body is loaded into the furnace. Through debinding and sintering, a ceramic green body with an internal adsorption electrode layer is obtained. An example can be implemented as follows: First, in air or a protective atmosphere, the temperature is increased from room temperature to 500-750℃ at a rate of 0.2-1℃ / min and held for 0.5-2 hours. Then, under a protective atmosphere, the temperature is further increased to 1400-1800℃ at a rate of 1.5-5℃ / min and held for 2-5 hours. After holding, the temperature is reduced to below 200℃ at a rate of 1-3℃ / min, and then cooled in the furnace.

[0038] S3-1: Polishing: Polish the upper and lower surfaces of the sintered ceramic blank from step S2-6. The parallelism between the upper and lower surfaces should be less than 50μm to obtain ceramic layer 31.

[0039] S3-2: Printing of heating electrodes and sintering curing: A heating electrode layer 33 is printed on the lower surface of the polished ceramic layer 31. The ceramic layer 31 is then placed in an oven and dried at 80-150℃ for 10-20 minutes. Next, it is sintered at 1400-1700℃ for 10-60 minutes under nitrogen protection to cure the conductive paste. The conductive paste used for printing is either a tungsten-molybdenum metal conductive paste or a ceramic conductive paste doped with a conductive phase.

[0040] S3-3: Preparation of the glass layer and sintering: A glass layer 34 of a certain thickness is obtained on the lower surface of the ceramic layer 31 and the lower surface of the heating electrode layer 33 by printing or spraying. The ceramic layer 31 with the glass layer 34 is heated to 950-1200℃ and sintered for 1-3 hours, then cooled naturally to obtain the ceramic body 30. The glass layer 34 is aluminosilicate glass, quartz glass, zirconium-doped quartz glass, or borosilicate glass, etc.

[0041] S4-1: First, braze the electrode posts to the electrode holes on the ceramic body 30. The electrode posts are connected to the adsorption electrode layer 32 and the heating electrode layer 33 respectively. The brazing solder used in the brazing process is gold-germanium-based solder or modified silver-copper-titanium-based solder. The brazing process takes place in a vacuum degree of less than 10°C. -3 In a Pa environment, the heating rate is 5-20℃ / min.

[0042] S4-2: Bonding process: A bonding material layer 20 is printed on the upper surface of the metal base 10. After multiple printings to make the bonding material layer 20 reach a thickness of 200-300μm, the ceramic body 30 with the brazed electrode posts is installed to obtain the required electrostatic chuck.

[0043] In step S3, the prepared glass layer 34 needs to be matched with the ceramic layer 31 in terms of thermal expansion coefficient to avoid delamination and cracking during sintering. Increasing the alumina content in aluminosilicate glass can make the glass network more complete, thereby increasing the softening temperature; changing the relative content of alumina and silicon dioxide and the content of alkali metals in aluminosilicate glass can also make the thermal expansion coefficient of aluminosilicate glass between 4-9×10⁻⁶. -6 / K interval adjustment (i.e., 4×10) -6 / K to 9×10 -6 Regardless of whether the main body of the ceramic layer 31 is alumina or aluminum nitride, the coefficient of thermal expansion of the glass layer can be close to that of the ceramic layer. Therefore, it can be concluded that aluminosilicate glass is superior as the glass layer 34 compared to other glasses. This invention also provides an aluminosilicate glass with the following composition by mass percentage: silicon dioxide 40-75%, alumina 15-45%, lithium oxide 2-6%, sodium oxide 4-7%, potassium oxide 0.5-2%, magnesium oxide 1-3%, and calcium oxide 0.5-2%.

[0044] In step S4, the brazing temperature should be lower than the softening temperature of the glass layer, preferably more than 150°C, so that the glass layer can maintain a good solid shape during brazing. The aluminosilicate glass of this invention has a softening point between 850-1050°C, depending on the alumina content. It is preferably brazed using solders such as gold-germanium based solder (brazing temperature 300-400°C) or silver-copper-titanium based solder (brazing temperature 650-900°C). As an example of silver-copper-titanium based solder, it can be prepared according to the method provided in patent publication CN118455834B, specifically by adding nickel, aluminum, tin, and other raw materials to a general silver-copper-titanium based solder to lower the melting temperature of the solder.

[0045] The following also provides a method for printing glass layer 34: Avoiding the locations of the adsorption electrode holes and the reserved heating electrode holes, aluminosilicate glass paste is screen-printed onto the lower surface of ceramic layer 31, and then dried in an oven at 80-150℃ for 10-20 minutes. The aluminosilicate glass paste is made by thoroughly mixing and grinding an organic carrier, functional phase, and additives. The organic carrier includes solvents such as butyl carbitol or terpineol, methylcellulose or ethylcellulose, and acrylic resin, accounting for 19-39% of the total mass of the paste; the functional phase is aluminosilicate glass powder, accounting for 60-80% of the total mass of the paste; the additives include thixotropic agent fumed silica and defoamer, accounting for 0.1-1% and 0.1-0.5% of the total mass of the paste, respectively. The ceramic layer 31 with glass layer 34 is heated to 950-1200℃ and sintered for 1-3 hours, then allowed to cool naturally. The printing of aluminosilicate glass paste and the sintering process of glass layer 34 are repeated until the thickness of glass layer 34 reaches 80-150 μm.

[0046] The key design focus of this invention is: First, this invention divides the ceramic body of the electrostatic chuck into two parts, which are prepared using multi-layer co-fired ceramic technology and printing sintering methods, respectively. Specifically, the ceramic layers are prepared using multi-layer co-fired ceramic technology, meaning only the adsorption electrode layer is prepared through co-firing. Compared to the conventional method of co-firing the adsorption and heating layers together, the number of co-fired layers is significantly reduced. Because the amount of green ceramic sheets used is reduced, the possibility of poor interlayer bonding is decreased, avoiding defects such as delamination and bulging during subsequent binder removal due to poor interlayer bonding, thus improving the yield rate. Furthermore, the thinner co-fired body reduces the difficulty of co-firing and lowers the complexity of the process.

[0047] Secondly, in this invention, the heating electrode layer is prepared on the lower surface of the ceramic layer through printing and sintering. Since the ceramic layer is already sintered, its dimensions are stable and precise after fine polishing of both surfaces, ensuring the uniformity of the heating electrode layer thickness and its parallelism relative to the chuck surface. Compared to the conventional method of printing the heating electrode layer onto a green ceramic substrate, this avoids the quality problem of uneven thickness in the green ceramic substrate, which affects the uniformity of the heating electrode layer thickness and ultimately leads to uneven resistance and uneven heating temperature. The heating electrode layer of this invention has a more uniform thickness, resulting in consistent heating power throughout the wafer during operation, providing uniform heating.

[0048] Furthermore, in this invention, the heating electrode layer is located between the ceramic layer and the glass layer. Since the thermal conductivity of the glass layer is much lower than that of the ceramic layer, only one-tenth of the latter, the heat generated by the heating electrode layer is more easily concentrated and transferred upward to the wafer, resulting in faster heating, shorter wafer temperature rise response time, and improved effective heating efficiency.

[0049] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An internally heated electrostatic chuck that is easy to manufacture and provides uniform heating, characterized in that: The ceramic body of the electrostatic chuck includes a ceramic layer, an adsorption electrode layer, a heating electrode layer, and a glass layer. The ceramic layer and the adsorption electrode layer are prepared by co-firing technology. The adsorption electrode layer is formed inside the ceramic layer. The heating electrode layer and the glass layer are prepared sequentially on the lower surface of the ceramic layer by printing and sintering. The heating electrode layer is located between the ceramic layer and the glass layer.

2. The internally heated electrostatic chuck according to claim 1, which is easy to manufacture and provides uniform heating, is characterized in that: The electrostatic chuck also includes a metal base and a bonding material layer. The metal base is made of metal or alloy, and the bonding material layer is made of silicone or elastic polymer. The bonding material layer is stacked and fixed on the upper surface of the metal base and located on the lower surface of the glass layer.

3. A method for preparing an internally heated electrostatic chuck that is easy to manufacture and provides uniform heating, as described in any one of claims 1-2, characterized in that: It includes the following steps: S1: Green ceramic tape is prepared through slurry preparation and casting process; S2: The ceramic layer and the adsorption electrode layer within the ceramic layer are obtained using multilayer co-fired ceramic technology; The process of the multi-layer co-fired ceramic technology includes: first, cutting, punching, screen printing and / or filling the holes of the green ceramic strip, stacking and pressing to form a ceramic green body; then, machining, debinding and sintering the green body to form a ceramic body. S3: The heating electrode layer and the glass layer are sequentially prepared on the lower surface of the ceramic layer by printing and sintering to obtain the ceramic body of the electrostatic chuck.

4. The method for preparing an internally heated electrostatic chuck that is easy to manufacture and provides uniform heating according to claim 3, characterized in that: It also includes the following steps: S4: The electrode post is brazed into the electrode hole of the ceramic body, and finally the ceramic body is connected to the metal base by bonding process.

5. The method for preparing an internally heated electrostatic chuck that is easy to manufacture and provides uniform heating according to claim 3, characterized in that: The slurry in step S1 includes ceramic aggregates, sintering aids, and may or may not contain resistance modifiers. The ceramic aggregate is aluminum oxide or aluminum nitride. The resistance regulator is at least one of titanium oxide, titanium nitride, titanium, calcium oxide, vanadium nitride, tantalum nitride, titanium carbide, and molybdenum carbide. The mass ratio of the ceramic aggregate, sintering aid, and resistance regulator is 100:(0.5-5):(1-20).

6. The method for preparing an internally heated electrostatic chuck that is easy to manufacture and provides uniform heating according to claim 3, characterized in that: The conductive paste used for filling holes and printing in steps S2 and S3 is a tungsten-molybdenum metal conductive paste or a ceramic conductive paste doped with a conductive phase; and in step S2, the viscosity of the conductive paste used for filling holes is 20,000-100,000 cp, and the viscosity of the conductive paste used for printing in steps S2 and S3 is 2,000-10,000 cp.

7. The method for preparing an internally heated electrostatic chuck that is easy to manufacture and provides uniform heating according to claim 3, characterized in that: In step S3, the glass layer contains aluminosilicate glass, quartz glass, zirconium-doped quartz glass, or borosilicate glass.

8. The method for preparing an internally heated electrostatic chuck that is easy to manufacture and provides uniform heating according to claim 7, characterized in that: The aluminosilicate glass comprises the following components by mass percentage: silicon dioxide 40-75%, aluminum oxide 15-45%, lithium oxide 2-6%, sodium oxide 4-7%, potassium oxide 0.5-2%, magnesium oxide 1-3%, and calcium oxide 0.5-2%.

9. A method for preparing an internally heated electrostatic chuck that is easy to manufacture and provides uniform heating, as described in claim 3 or 7, characterized in that: The method for preparing the glass layer in step S3 is as follows: First, avoiding the locations of the adsorption electrode holes and the reserved heating electrode holes, screen print aluminum-silicon glass paste on the lower surface of the ceramic layer; then place it in an oven and dry it at 80-150℃ for 10-20 minutes; heat the ceramic layer with the glass layer to 950-1200℃ and sinter for 1-3 hours, then let it cool naturally; repeat the process of printing aluminum-silicon glass paste and sintering the glass layer until the glass layer thickness reaches 80-150μm.

10. The method for preparing an internally heated electrostatic chuck that is easy to manufacture and provides uniform heating according to claim 9, characterized in that: The aluminosilicate glass slurry is formed by thoroughly mixing and grinding an organic carrier, a functional phase, and additives. The organic carrier includes solvents such as butyl carbitol or terpineol, methyl cellulose or ethyl cellulose, and acrylic resin, accounting for 19-39% of the total mass of the slurry. The functional phase is aluminosilicate glass powder, accounting for 60-80% of the total mass of the slurry. The additives include thixotropic fumed silica and defoamer, accounting for 0.1-1% and 0.1-0.5% of the total mass of the slurry, respectively.

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