Composite dielectric material, method for manufacturing the same, and electrostatic chuck

Abstract

The application discloses a kind of composite dielectric material and preparation method thereof, electrostatic chuck, belong to electrostatic chuck technical field, composite dielectric material includes: ZrO2 Powder, Al2O3 Powder, Y2O3 Powder and SiO2 Powder, wherein, the weight ratio of ZrO2 Powder and Al2O3 Powder is 28~32:1 or 12~14:1, the weight percentage of SiO2 Powder is 5wt%, and the content of Y2O3 Powder is 4~6 mol% relative to ZrO2 Powder.The preparation method comprises: weighing ZrO2 Powder, Al2O3 Powder, Y2O3 Powder and SiO2 Powder according to the design ratio, and then uniformly mixing;Subsequently, heat treatment is carried out at 1300°C for 4~5 hours under air atmosphere;Then dry pressing forming is carried out, and after dry pressing forming, hot-pressing sintering is carried out at a temperature of 1500~1800°C, to prepare the composite dielectric material.

Description

Technical Field

[0001] This invention relates to the field of electrostatic chuck technology, and in particular to a composite dielectric material and its preparation method, and an electrostatic chuck. Background Technology

[0002] Alumina (Al₂O₃) is widely used as the dielectric material for electrostatic chucks due to its excellent insulating properties. To improve performance, especially to enable it to operate in the stronger and more stable Johnsen-Rahbek (JR) mode, Al₂O₃ typically requires doping modification. Currently, the industry commonly uses titanium dioxide (TiO₂) doping to reduce the volume resistivity of Al₂O₃ to achieve the JR mode.

[0003] However, this method has the following drawbacks: the decrease in resistivity is often accompanied by a decrease in the electrical stability of the material, leading to a reduction in breakdown voltage and affecting the long-term reliability and safety of the electrostatic chuck. Therefore, there is an urgent need to develop a composite dielectric material and its preparation method. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a composite dielectric material and its preparation method, as well as an electrostatic chuck, which can significantly improve dielectric properties and induce strong JR adsorption force while maintaining high breakdown strength and excellent stability.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A composite dielectric material, comprising:

[0007] The powder consists of ZrO2 powder, Al2O3 powder, Y2O3 powder, and SiO2 powder, wherein the weight ratio of ZrO2 powder to Al2O3 powder is 28–32:1 or 12–14:1, the weight percentage of SiO2 powder is 5 wt%, and the content of Y2O3 powder is 4–6 mol relative to ZrO2 powder.

[0008] Preferably, the weight ratio of ZrO2 powder to Al2O3 powder is 28 to 32:1.

[0009] Preferably, the weight ratio of ZrO2 powder to Al2O3 powder is 30:1.

[0010] A method for preparing the composite dielectric material as described above, the method comprising the following steps:

[0011] Weigh ZrO2 powder, Al2O3 powder, Y2O3 powder and SiO2 powder according to the design ratio, mix the weighed powders together, and then use a planetary ball mill at 180-220 rpm for 3-6 hours to make them uniformly mixed.

[0012] Subsequently, the mixture was heat-treated at 1300℃ for 4–5 hours in air to promote the formation of stable YSZ and ZrSiO4 phases.

[0013] Finally, the powder is cooled, sieved, and then dry-pressed. After dry pressing, it is hot-pressed and sintered at a temperature of 1500-1800℃. The pressure of hot pressing and sintering is 28-34 MPa. The heating program is as follows: the heating rate is 5℃ / min in the temperature range of 50-1000℃, and the temperature is continued to rise to the sintering temperature at a heating rate of 2℃ / min. After the sintering temperature stabilizes, it is held for 2-3 hours and then cooled in the furnace to obtain a ceramic sample, thus preparing a composite dielectric material.

[0014] Preferably, after dry pressing, hot pressing sintering is carried out at 1800℃. The pressure of hot pressing sintering is 30MPa. The heating program is as follows: the heating rate is 5℃ / min in the temperature range of 50~1000℃, and the temperature is continued to rise to 1800℃ at a heating rate of 2℃ / min. After the temperature stabilizes at 1800℃, it is held at that temperature for 2 hours and then cooled in the furnace to obtain a ceramic sample, thus preparing a composite dielectric material.

[0015] An electrostatic chuck prepared using the aforementioned composite dielectric material, wherein the electrostatic chuck exhibits an adsorption force on a glass substrate greater than 20 gf / cm. 2

[0016] Preferably, the breakdown voltage of the electrostatic chuck is 4100–4300V, and the dielectric strength is 16–18V / μm.

[0017] The above technical solution has the following beneficial effects:

[0018] Compared to existing technologies, the high-performance electrostatic chuck dielectric material prepared by this invention exhibits strong JR adsorption force (25 gf / cm). 2 While maintaining a high breakdown voltage (4200 V) and good mechanical properties, it can meet the requirements of next-generation semiconductor manufacturing for high-precision and high-reliability wafer clamping; in addition, the dry pressing process results in high material utilization and high stability. Attached Figure Description

[0019] Figure 1 The figure shows the adsorption force test results of the electrostatic chuck prepared from the composite dielectric material of this invention. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0021] A composite dielectric material, comprising:

[0022] The mixture comprises ZrO2 powder, Al2O3 powder, Y2O3 powder, and SiO2 powder, wherein the weight ratio of ZrO2 powder to Al2O3 powder is 28–32:1 or 12–14:1, the weight percentage of SiO2 powder is 5 wt%, and the content of Y2O3 powder is 4–6 mol% relative to ZrO2 powder.

[0023] Specifically, the composite dielectric material includes ZrO2 powder, Al2O3 powder, Y2O3 powder, and SiO2 powder. The weight ratio of ZrO2 powder to Al2O3 powder is 28–32:1 or 12–14:1, specifically 28:1, 32:1, 12:1, or 14:1. The preferred weight ratio is 28–32:1, and a more preferred ratio is 30:1. The weight percentage of SiO2 powder is fixed at 5 wt%, and the content of Y2O3 powder is 4 mol% or 6 mol% relative to ZrO2 powder.

[0024] The composite dielectric material of this application is used to prepare electrostatic chucks, which solves the problem that the existing technology uses doping with titanium dioxide to reduce the volume resistivity of Al2O3 in order to achieve JR mode. However, the reduction of resistivity is often accompanied by a decrease in the electrical stability of the material, resulting in a decrease in breakdown voltage, which affects the long-term working reliability and safety of the electrostatic chuck.

[0025] This invention abandons the traditional TiO2-doped Al2O3 system, adopting a ZrO2 / Al2O3 composite system as the matrix, and synergistically doping with Y2O3 and SiO2. By precisely controlling the weight ratio of ZrO2 to Al2O3 and fixing the SiO2 content at 5 wt% and the Y2O3 content at 4-6 mol% relative to ZrO2, a new composite material is formed. This composite material utilizes the high dielectric constant (approximately 25) of ZrO2 to enhance electrostatic adsorption, utilizes Y2O3 to stabilize the zirconium oxide phase and moderately adjust the ionic conductivity, and utilizes SiO2 to form a high-strength zirconium silicate (ZrSiO4) phase to enhance mechanical properties. Thus, optimal synergy is achieved among dielectric constant, resistivity, breakdown strength, and mechanical strength. The composite dielectric material is then prepared through dry pressing and sintering processes.

[0026] The composite dielectric material obtained by this invention solves the contradiction between "enhancing adsorption force" and "maintaining high insulation strength" that is difficult to achieve simultaneously in traditional materials. Specifically, the coating with the preferred composition (ZrO2 / Al2O3=30) achieves a relative permittivity of 22 and a dielectric constant of 1.0 × 10⁻⁶. 14 The volume resistivity of Ω·cm effectively induces the JR effect, resulting in an electrostatic chuck adsorption force of up to 25 gf / cm² on the glass substrate, far exceeding the industrial standard of 10-15 gf / cm². At the same time, the material exhibits a breakdown voltage of 4200 V and a dielectric strength of about 17 V / μm, and its voltage stability is significantly better than that of traditional TiO2-doped Al2O3 materials (breakdown voltage of about 3000 V).

[0027] A method for preparing the composite dielectric material as described above, the method comprising the following steps:

[0028] Weigh ZrO2 powder, Al2O3 powder, Y2O3 powder, and SiO2 powder according to the designed ratio, mix the weighed powders together, and then use a planetary ball mill at 180-220 rpm for 3-6 hours to achieve uniform mixing. Specifically, weigh ZrO2 powder, Al2O3 powder, Y2O3 powder, and SiO2 powder according to the designed ratio, mix them together, and then use a planetary ball mill at 180 or 220 rpm for 3 or 6 hours to achieve uniform mixing.

[0029] Subsequently, the mixture is heat-treated at 1300℃ in air for 4 to 5 hours to promote the formation of stable YSZ and ZrSiO4 phases; specifically, the heat treatment time can be 4 or 5 hours.

[0030] Finally, the powder is cooled, sieved, and then dry-pressed. After dry pressing, it is hot-pressed and sintered at a temperature of 1500-1800℃. The pressure of hot pressing and sintering is 28-34MPa. The heating program is as follows: the heating rate is 5℃ / min in the temperature range of 50-1000℃, and the temperature is continued to rise to the sintering temperature at a heating rate of 2℃ / min. After the sintering temperature stabilizes, it is held for 2-3 hours and then cooled in the furnace to obtain a ceramic sample, thus preparing a composite dielectric material.

[0031] Specifically, the hot pressing sintering temperature is in the range of 1500 to 1800℃, specifically 1500℃ or 1800℃. The hot pressing sintering pressure is 28MPa or 34MPa, or 30MPa. The heating rate in the temperature range of 50 to 1000℃ is 5℃ / min, and the temperature is continued to rise to the sintering temperature at a heating rate of 2℃ / min. After the sintering temperature stabilizes, it is held at that temperature for 2h or 3h.

[0032] In some embodiments, the hot pressing sintering temperature is 1800℃. After dry pressing, hot pressing sintering is performed at 1800℃. The pressure of hot pressing sintering is 30MPa. The heating program is as follows: the heating rate is 5℃ / min in the temperature range of 50~1000℃, and the temperature is continued to rise to 1800℃ at a heating rate of 2℃ / min. After the temperature stabilizes at 1800℃, it is held at that temperature for 2 hours. The ceramic sample is obtained by cooling in the furnace, and the composite dielectric material is prepared.

[0033] An electrostatic chuck prepared using the aforementioned composite dielectric material exhibits an adsorption force on a glass substrate greater than 20 gf / cm. 2 .

[0034] In some embodiments, the breakdown voltage of the electrostatic chuck is 4100–4300V and the dielectric strength is 16–18V / μm; specifically, the breakdown voltage of the electrostatic chuck can be 4200V and the dielectric strength can be 17V / μm.

[0035] Compared to existing technologies, this invention develops a high-performance electrostatic chuck dielectric material through a unique material composition design; this material induces strong JR adsorption force (25 gf / cm). 2 While maintaining a high breakdown voltage (4200 V) and good mechanical properties, it can meet the requirements of next-generation semiconductor manufacturing for high-precision and high-reliability wafer clamping; in addition, the dry pressing process results in high material utilization and high stability.

[0036] Example 1

[0037] Weigh ZrO2, Al2O3, Y2O3, and SiO2 raw materials according to the designed proportions. Set three different ZrO2 / Al2O3 weight ratios: 30:1, 13:1, and 3:1. The doping amount of Y2O3 is fixed at 4–6 mol% relative to ZrO2, and the doping amount of SiO2 is fixed at 5 wt%.

[0038] After mixing the powders, they were ball-milled at 200 rpm for 4 hours using a planetary ball mill to ensure uniform mixing. Subsequently, they were heat-treated at 1300°C for 4 hours in air atmosphere to promote the formation of stable YSZ and ZrSiO4 phases.

[0039] Finally, the powder was cooled, sieved, and then dry-pressed. It was then hot-pressed and sintered at 1800℃ under a pressure of 30 MPa. The heating program was as follows: a heating rate of 5℃ / min within the temperature range of 50–1000℃, and a heating rate of 2℃ / min within the temperature range of 1000–1800℃. The mixture was held at 1800℃ for 2 hours and then cooled in the furnace to obtain a ceramic sample, thus preparing a composite dielectric material. (Reference) Figure 1From left to right, the adsorption forces of the ZrO2 / Al2O3 weight ratios are 30:1, 13:1, and 3:1. When the ZrO2 / Al2O3 weight ratio is 30:1, the adsorption force of the prepared electrostatic chuck is 25 gf / cm. 2 When the ZrO2 / Al2O3 weight ratio is 13:1, the adsorption force of the prepared electrostatic chuck is 17.5 gf / cm. 2 When the ZrO2 / Al2O3 weight ratio is 3:1, the adsorption force of the prepared electrostatic chuck is 12.5 gf / cm. 2 In this embodiment, a preferred weight ratio of 30:1 induces strong JR adsorption (25 gf / cm). 2 ).

[0040] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A composite dielectric material, characterized in that, include: The powder consists of ZrO2 powder, Al2O3 powder, Y2O3 powder, and SiO2 powder, wherein the weight ratio of ZrO2 powder to Al2O3 powder is 28–32:1 or 12–14:1, the weight percentage of SiO2 powder is 5 wt%, and the content of Y2O3 powder is 4–6 mol relative to ZrO2 powder.

2. The composite dielectric material according to claim 1, characterized in that, The weight ratio of ZrO2 powder to Al2O3 powder is 28 to 32:

1.

3. The composite dielectric material according to claim 2, characterized in that, The weight ratio of ZrO2 powder to Al2O3 powder is 30:

1.

4. A method for preparing a composite dielectric material as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: Weigh ZrO2 powder, Al2O3 powder, Y2O3 powder and SiO2 powder according to the design ratio, mix the weighed powders together, and then use a planetary ball mill at 180-220 rpm for 3-6 hours to make them uniformly mixed. Subsequently, the mixture was heat-treated at 1300℃ for 4–5 hours in air to promote the formation of stable YSZ and ZrSiO4 phases. Finally, the powder is cooled, sieved, and then dry-pressed. After dry pressing, it is hot-pressed and sintered at a temperature of 1500-1800℃. The pressure of hot pressing and sintering is 28-34 MPa. The heating program is as follows: the heating rate is 5℃ / min in the temperature range of 50-1000℃, and the temperature is continued to rise to the sintering temperature at a heating rate of 2℃ / min. After the sintering temperature stabilizes, it is held for 2-3 hours and then cooled in the furnace to obtain a ceramic sample, thus preparing a composite dielectric material.

5. The method for preparing the composite dielectric material according to claim 4, characterized in that, After dry pressing, the material is hot-pressed and sintered at 1800℃. The pressure of the hot-pressing sintering is 30MPa. The heating program is as follows: the heating rate is 5℃ / min in the temperature range of 50~1000℃, and the temperature is continued to rise to 1800℃ at a heating rate of 2℃ / min. After the temperature stabilizes at 1800℃, it is held at that temperature for 2 hours and then cooled in the furnace to obtain a ceramic sample, thus preparing a composite dielectric material.

6. An electrostatic chuck prepared using the composite dielectric material as described in claim 3, characterized in that, The electrostatic chuck has an adsorption force greater than 20 gf / cm on the glass substrate. 2 .

7. The composite dielectric material and its preparation method according to claim 6, characterized in that, The breakdown voltage of the electrostatic chuck is 4100–4300V, and the dielectric strength is 16–18V / μm.

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