Electrostatic chuck aluminum nitride face plate material and preparation method thereof

Abstract

The invention discloses an electrostatic chuck aluminum nitride face plate material and a preparation method thereof.The preparation method comprises the following steps that firstly, aluminum nitride powder, titanium nitride powder, titanium oxide powder and yttrium oxide powder are subjected to vacuum drying, and the mass ratio of the aluminum nitride powder to the titanium nitride powder to the yttrium oxide powder is (90-100): (3-15): (1-3): (2-6); step 2, performing wet mixing and ball milling on the product obtained in the step 1, drying, grinding and sieving to obtain uniformly dispersed ceramic powder; step 3, filling a mold with the ceramic powder, pre-pressing, maintaining the pressure when the pressure is increased to 30-100 MPa to obtain a ceramic pre-pressed blank, and carrying out vacuum drying to obtain a blank body; and 4, carrying out hot pressed sintering on the green body, applying a load when the temperature rises to 1600-1800 DEG C, and carrying out furnace cooling. The material of the aluminum nitride face plate of the electrostatic chuck is an aluminum nitride / titanium nitride ceramic material. The process engineering adopted by the invention is compact, and hydrolysis of aluminum nitride in air is reduced; the mechanical strength is excellent, and the resistivity is stable.

Description

Technical Field

[0001] This invention pertains to ceramic materials and their manufacturing methods, specifically to an electrostatic chuck aluminum nitride faceplate material and its preparation method. Background Technology

[0002] Early semiconductor processes used mechanical clamping or vacuum chucks to hold wafers, but mechanical clamping easily damaged wafer edges, and vacuum chucks failed in a vacuum environment and suffered from uneven heat dissipation. As process precision increased to the nanometer level, the demands for wafer flatness, temperature uniformity, and low contamination spurred the need for electrostatic adsorption technology. Electrostatic chucks create an electrostatic field between the electrodes and the wafer by applying a DC voltage, utilizing the Coulomb force or the Johnsen-Rahbek (JR) effect to adsorb the wafer. Among these, the JR-type chuck has a stronger adsorption force (up to 10⁻⁶) due to the limited resistance of its dielectric layer. 4 -10 5 Aluminum nitride (AN) has become the mainstream technology. Advanced processes (such as below 5nm) have stringent requirements for temperature control accuracy, necessitating zoned temperature control technology (increasing the temperature zones from 2 to over 100 zones), while also needing compatibility with high vacuum and plasma environments, thus driving aluminum nitride materials to become the mainstream material.

[0003] Existing methods for preparing aluminum nitride electrostatic chucks suffer from drawbacks such as complex preparation processes, high preparation costs, low thermal conductivity, and uncontrollable and mismatched resistivity in electrical properties. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a method for preparing an electrostatic chuck aluminum nitride faceplate material that is low in cost, easy to operate and highly processable. Another purpose of this invention is to provide an electrostatic chuck aluminum nitride faceplate material with good mechanical properties and adjustable resistivity and thermal conductivity.

[0005] Technical solution: The present invention provides a method for preparing an aluminum nitride faceplate material for an electrostatic chuck, comprising the following steps:

[0006] Step 1, powder drying: Vacuum drying of aluminum nitride, titanium nitride, titanium oxide, and yttrium oxide powders in a mass ratio of 90~100:3~15:1~3:2~6;

[0007] Step 2, Preparation of mixed powder: The material obtained in Step 1 is wet-mixed ball milled, dried, and then ground and sieved to obtain uniformly dispersed ceramic powder;

[0008] Step 3, pre-pressing: Ceramic powder is filled into the mold and pre-pressed. When the pressure rises to 30~100 MPa, the pressure is held to obtain the ceramic pre-pressed blank. Vacuum drying is then performed to obtain the blank.

[0009] Step 4, hot pressing sintering: The billet is hot pressed and sintered. When the temperature rises to 1600~1800℃, a load is applied. After cooling with the furnace, the electrostatic chuck aluminum nitride faceplate material is obtained.

[0010] Furthermore, in step one, the vacuum drying temperature is 25~80℃, and the vacuum drying time is 20~60 hours.

[0011] Furthermore, in step two, the wet mixing medium for wet ball milling is anhydrous ethanol.

[0012] Furthermore, in step two, the wet ball milling speed is 300~400 r / min, and the time is 24~30 hours.

[0013] Furthermore, in step two, the drying temperature is 40~80℃, the drying time is 20~80 hours, and the wet-mixed ball mill is immediately placed into a rotary evaporator for drying.

[0014] Furthermore, in step two, the sieving is performed through a 200-400 mesh sieve.

[0015] Furthermore, in step three, pre-compression is performed using a hydraulic press, and the pressure holding time is 30-50 minutes.

[0016] Furthermore, in step three, the vacuum drying temperature is 80~200℃, and the vacuum drying time is 6~30 hours.

[0017] Furthermore, in step three, the load is applied when the temperature rises to 1600°C, and the pressure rises to 30 MPa when the temperature rises to 1800°C. This temperature and pressure are maintained for 1-2 hours.

[0018] The electrostatic chuck aluminum nitride faceplate material of this invention is an aluminum nitride / titanium nitride ceramic material with a flexural strength of 450~502MPa and a fracture toughness of 3.7~5MPa·m. 1 / 2 The resistivity is 10 4 ~10 14 Ω·cm, thermal conductivity is 150~200W / (m·K).

[0019] Preparation principle: Titanium nitride and titanium oxide are used as resistance modifiers, and yttrium oxide is used as a sintering aid. During preparation, titanium nitride and titanium oxide form a conductive network material with adjustable resistance due to point defects. This network serves as both a primary source of point defects in the solid solution phase and as dispersed particles of the second phase. Yttrium oxide acts as a sintering aid for the glassy phase, filling the grain boundaries of aluminum nitride / titanium nitride, etc.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0021] 1. The process adopted is compact, which reduces the risk of aluminum nitride being hydrolyzed in the air and increasing impurities;

[0022] 2. Pre-pressed aluminum nitride exhibits superior mechanical strength compared to directly hot-pressed sintered aluminum nitride, and its resistivity can be maintained relatively stably.

[0023] 3. Titanium nitride and titanium oxide are used as resistance modifiers, and the resistivity and thermal conductivity of the prepared aluminum nitride / titanium nitride ceramics can be adjusted according to the content of titanium nitride.

[0024] 4. The prepared aluminum nitride / titanium nitride faceplate ceramic material achieved a flexural strength of 450~500MPa and a fracture toughness of 3.7~5MPa·m. 1 / 2 . Attached Figure Description

[0025] Figure 1 This is the XRD pattern of the product obtained in Embodiment 1 of the present invention;

[0026] Figure 2 This is a microstructure diagram of the product obtained in Example 3 of the present invention. Detailed Implementation

[0027] Unless otherwise specified, all materials and reagents used in the following embodiments are commercially available. Experimental methods not specifically described in the embodiments are generally performed under standard conditions or as recommended by the manufacturer.

[0028] Example 1

[0029] A method for preparing an electrostatic chuck aluminum nitride faceplate material with adjustable resistivity and thermal conductivity includes the following steps:

[0030] (1) Powder drying: First, put the raw materials aluminum nitride, titanium nitride, titanium oxide and yttrium oxide powders with different contents into a vacuum oven and dry them at 40°C for 40 hours. The particle size of aluminum nitride powder is 0.5μm, the particle size of titanium nitride is 30nm, the particle size of titanium oxide is 10nm and the particle size of yttrium oxide is 30nm.

[0031] (2) The raw materials consist of aluminum nitride, titanium nitride, and yttrium oxide, with titanium nitride and titanium oxide serving as resistance modifiers and yttrium oxide as a sintering aid. 90g of aluminum nitride with a particle size of 0.5μm, 15g of titanium nitride with a particle size of 30nm, 5g of titanium oxide with a particle size of 10nm, and 5g of yttrium oxide with a particle size of 30nm were wet-mixed using anhydrous ethanol. The raw materials were then ball-milled at 400r / min for 24h with a ball-to-material ratio of 1:2. The wet-mixed powder was then dried at 50℃ for 50 hours using a rotary evaporator. After grinding and passing through a 300-mesh sieve, uniformly dispersed ceramic powder was obtained.

[0032] (3) Pre-pressing: The mixed powder is filled into the mold and pre-pressed using a hydraulic press. When the pressure rises to 30MPa, it is held for 30 minutes to obtain the ceramic pre-pressed blank. Before proceeding to the next step after pressing, it is placed in a vacuum oven at 150℃ and dried for 24 hours.

[0033] (4) Hot pressing sintering: Aluminum nitride / titanium nitride ceramics are prepared by hot pressing sintering process. The green body is hot pressed and sintered. When the temperature rises to 1600℃, the load is applied. When the temperature rises to 1800℃, the pressure rises to 30 MPa. The temperature and pressure are maintained for 1.5h. After cooling in the furnace, aluminum nitride / titanium nitride ceramics are obtained.

[0034] The aluminum nitride / titanium nitride ceramic material finally obtained in this embodiment has a flexural strength of 501.21 MPa and a fracture toughness of 4.77 MPa·m. 1 / 2 The resistivity is 5.23 × 10⁻⁶. 4 Ω·cm, thermal conductivity is 156.42 W / (m·K).

[0035] like Figure 1 The XRD pattern of the product after adding titanium nitride and titanium oxide shows the presence of characteristic peaks of titanium nitride.

[0036] Example 2

[0037] A method for preparing an electrostatic chuck aluminum nitride faceplate material with adjustable resistivity and thermal conductivity includes the following steps:

[0038] (1) Powder drying: First, put the raw materials aluminum nitride, titanium nitride, titanium oxide and yttrium oxide powders with different contents into a vacuum oven and dry them at 60°C for 40 hours. The particle size of aluminum nitride powder is 1μm, the particle size of titanium nitride is 50nm, the particle size of titanium oxide is 30nm and the particle size of yttrium oxide is 50nm.

[0039] (2) Preparation of mixed powder: First, 92 g of aluminum nitride, 5 g of yttrium oxide, 3 g of titanium nitride, 1 g of titanium oxide and an appropriate amount of anhydrous ethanol were mixed together for wet mixing. The wet mixing process was to put the raw materials and anhydrous ethanol into a ball mill jar and ball mill at 400 r / min for 24 h with a ball-to-material ratio of 1:2. Then, the wet-mixed powder was dried at 60°C for 50 hours using a rotary evaporator. After grinding and passing through a 300-mesh sieve, a uniformly dispersed ceramic powder was obtained.

[0040] (3) Pre-pressing: The mixed powder is filled into the mold and pre-pressed using a hydraulic press at a pressure of 35 MPa. The pressure is maintained for 30 min to obtain the pre-pressed ceramic blank.

[0041] (4) Hot pressing sintering: Aluminum nitride / titanium nitride ceramics are prepared by hot pressing sintering process. The green body is hot pressed and sintered. When the temperature rises to 1600℃, the load is applied. When the temperature rises to 1800℃, the pressure rises to 30 MPa. The temperature and pressure are maintained for 1.5h. After cooling in the furnace, aluminum nitride / titanium nitride ceramics are obtained.

[0042] The ceramic material obtained in this embodiment has a flexural strength of 470.86 MPa and a fracture toughness of 5.01 MPa·m. 1 / 2 The resistivity is 2.12 × 10⁻⁶. 11 Ω·cm, thermal conductivity is 180.22 W / (m·K).

[0043] Example 3

[0044] A method for preparing an electrostatic chuck aluminum nitride faceplate material with adjustable resistivity and thermal conductivity includes the following steps:

[0045] (1) Powder drying: First, put the raw materials aluminum nitride, titanium nitride, titanium oxide and yttrium oxide powders with different contents into a vacuum oven and dry them at 40°C for 40 hours. The particle size of aluminum nitride powder is 1.2μm, the particle size of titanium nitride is 30nm, the particle size of titanium oxide is 20nm and the particle size of yttrium oxide is 30nm.

[0046] (2) Preparation of different mixed powders: First, 94 g of aluminum nitride, 5 g of yttrium oxide, 1 g of titanium nitride, 1 g of titanium oxide and an appropriate amount of anhydrous ethanol were mixed together for wet mixing. The wet mixing process was to put the raw materials and anhydrous ethanol into a ball mill jar and ball mill at 400 r / min for 24 h with a ball-to-material ratio of 1:2. Then, the wet-mixed powder was dried at 80°C for 20 hours using a rotary evaporator. After grinding and passing through a 300-mesh sieve, uniformly dispersed ceramic powder was obtained.

[0047] (3) Pre-pressing: In a steel mold, a hydraulic press is used for pre-pressing at a pressure of 30 MPa. The pressure is maintained for 30 min. After pre-pressing, the mold is placed in a vacuum oven at 200°C for 6 hours before proceeding to the next step.

[0048] (4) Hot pressing sintering: Aluminum nitride / titanium nitride ceramics are prepared by hot pressing sintering process. The green body is hot pressed and sintered. When the temperature rises to 1600℃, the load is applied. When the temperature rises to 1800℃, the pressure rises to 30 MPa. The temperature and pressure are maintained for 1.5h. After cooling in the furnace, aluminum nitride / titanium nitride ceramics are obtained.

[0049] The ceramic material obtained in this embodiment has a flexural strength of 440.21 MPa and a fracture toughness of 4.20 MPa·m. 1 / 2 The resistivity is 8.44 × 10⁻⁶. 12Ω·cm, thermal conductivity is 190.65 W / (m·K).

[0050] Example 4

[0051] A method for preparing an electrostatic chuck aluminum nitride faceplate material with adjustable resistivity and thermal conductivity includes the following steps:

[0052] (1) Powder drying: First, put the raw materials aluminum nitride, titanium nitride, titanium oxide and yttrium oxide powders with different contents into a vacuum oven and dry them at 25°C for 60 hours. The particle size of aluminum nitride powder is 0.8μm, the particle size of titanium nitride is 30nm, the particle size of titanium oxide is 20nm and the particle size of yttrium oxide is 30nm.

[0053] (2) Preparation of different mixed powders: First, 94 g of aluminum nitride, 5 g of yttrium oxide, 1 g of titanium nitride, 3 g of titanium oxide and an appropriate amount of anhydrous ethanol were mixed together for wet mixing. The wet mixing process was to put the raw materials and anhydrous ethanol into a ball mill jar and ball mill at 300 r / min for 30 h with a ball-to-material ratio of 1:2. Then, the wet-mixed powder was dried at 40°C for 80 h using a rotary evaporator. After grinding and passing through a 200-mesh sieve, uniformly dispersed ceramic powder was obtained.

[0054] (3) Pre-pressing: In a steel mold, a hydraulic press is used for pre-pressing at a pressure of 30 MPa. The pressure is maintained for 50 min. After pre-pressing, the mold is placed in a vacuum oven at 200°C for 6 hours before proceeding to the next step.

[0055] (4) Hot pressing sintering: Aluminum nitride / titanium nitride ceramics are prepared by hot pressing sintering process. The green body is hot pressed and sintered. When the temperature rises to 1600℃, the load is applied. When the temperature rises to 1800℃, the pressure rises to 30 MPa. The temperature and pressure are maintained for 1 h. After cooling in the furnace, aluminum nitride / titanium nitride ceramics are obtained.

[0056] Example 5

[0057] A method for preparing an electrostatic chuck aluminum nitride faceplate material with adjustable resistivity and thermal conductivity includes the following steps:

[0058] (1) Powder drying: First, put the raw materials aluminum nitride, titanium nitride, titanium oxide and yttrium oxide powders with different contents into a vacuum oven and dry them at 80°C for 20 hours. The particle size of aluminum nitride powder is 0.8μm, the particle size of titanium nitride is 50nm, the particle size of titanium oxide is 20nm and the particle size of yttrium oxide is 50nm.

[0059] (2) Preparation of different mixed powders: First, 94 g of aluminum nitride, 5 g of yttrium oxide, 1 g of titanium nitride, 1 g of titanium oxide and an appropriate amount of anhydrous ethanol were mixed together for wet mixing. The wet mixing process was to put the raw materials and anhydrous ethanol into a ball mill jar and ball mill at 350 r / min for 27 h with a ball-to-material ratio of 1:2. Then, the wet-mixed powder was dried at 80°C for 20 hours using a rotary evaporator. After grinding and passing through a 400-mesh sieve, uniformly dispersed ceramic powder was obtained.

[0060] (3) Pre-pressing: In a steel mold, a hydraulic press is used for pre-pressing at a pressure of 30 MPa. The pressure is maintained for 40 min. After pre-pressing, the mold is placed in a vacuum oven at 80°C for 20 hours before proceeding to the next step.

[0061] (4) Hot pressing sintering: Aluminum nitride / titanium nitride ceramics are prepared by hot pressing sintering process. The green body is hot pressed and sintered. When the temperature rises to 1600℃, the load is applied. When the temperature rises to 1800℃, the pressure rises to 30 MPa. The temperature and pressure are maintained for 2 hours. After cooling in the furnace, aluminum nitride / titanium nitride ceramics are obtained.

[0062] Table 1 Performance parameters of aluminum nitride / titanium nitride ceramics in series 1, 2, 3, 4, and 5

[0063]

[0064] As shown in Table 1, the aluminum nitride / titanium nitride ceramic obtained in Example 2 exhibits the best overall mechanical properties, while the aluminum nitride / titanium nitride ceramic obtained in Example 3 has the highest resistivity. This is related to the titanium nitride content; as the titanium nitride content increases, its resistivity and thermal conductivity decrease, while its mechanical properties slightly improve. The aluminum nitride / titanium nitride ceramic obtained in Example 4 has the lowest thermal conductivity, which is related to the titanium oxide content. As the titanium oxide content increases, the thermal conductivity decreases.

Claims

1. A method for preparing an aluminum nitride faceplate material for an electrostatic chuck, characterized in that, Includes the following steps: Step 1: Vacuum dry aluminum nitride, titanium nitride, titanium oxide, and yttrium oxide powders in a mass ratio of 90~100:3~15:1~3:2~6; Step 2: The material obtained in Step 1 is wet-mixed and ball-milled, dried, and then ground and sieved to obtain a uniformly dispersed ceramic powder. Step 3: Fill the ceramic powder into the mold and pre-press it. When the pressure rises to 30~100 MPa, hold the pressure to obtain the ceramic pre-pressed blank. Vacuum dry to obtain the blank. Step four: hot pressing and sintering the billet. When the temperature rises to 1600~1800℃, a load is applied and the billet is cooled in the furnace to obtain the electrostatic chuck aluminum nitride faceplate material.

2. The method for preparing an aluminum nitride faceplate material for an electrostatic chuck according to claim 1, characterized in that: In step one, the aluminum nitride powder has a particle size of 0.5-1.2 μm, the titanium nitride has a particle size of 20-50 nm, the titanium oxide has a particle size of 10-30 nm, and the yttrium oxide powder has a particle size of 30-50 nm. The vacuum drying temperature is 25-80℃, and the vacuum drying time is 20-60 hours.

3. The method for preparing an aluminum nitride faceplate material for an electrostatic chuck according to claim 1, characterized in that: In step two, the wet mixing medium for wet ball milling is anhydrous ethanol.

4. The method for preparing an aluminum nitride faceplate material for an electrostatic chuck according to claim 1, characterized in that: In step two, the wet ball milling speed is 300~400 r / min, and the time is 24~30 hours.

5. The method for preparing an aluminum nitride faceplate material for an electrostatic chuck according to claim 1, characterized in that: In step two, the drying temperature is 40~80℃ and the drying time is 20~80 hours. After wet mixing and ball milling, the mixture is immediately placed in a rotary evaporator for drying.

6. The method for preparing an aluminum nitride faceplate material for an electrostatic chuck according to claim 1, characterized in that: In step two, the sieving is performed through a 200-400 mesh sieve.

7. The method for preparing an aluminum nitride faceplate material for an electrostatic chuck according to claim 1, characterized in that: In step three, pre-pressurization is performed using a hydraulic press, and the pressure holding time is 30-50 minutes.

8. The method for preparing an aluminum nitride faceplate material for an electrostatic chuck according to claim 1, characterized in that: In step three, the vacuum drying temperature is 80~200℃, and the vacuum drying time is 6~20 hours.

9. A method for preparing an aluminum nitride faceplate material for an electrostatic chuck according to claim 1, characterized in that: In step three, the load is applied when the temperature rises to 1600°C, and the pressure rises to 30 MPa when the temperature rises to 1800°C. This temperature and pressure are maintained for 1-2 hours.

10. The electrostatic chuck aluminum nitride faceplate material obtained by the preparation method of the electrostatic chuck aluminum nitride faceplate material according to claim 1, characterized in that: It is an aluminum nitride / titanium nitride ceramic material with a flexural strength of 450~502MPa and a fracture toughness of 3.7~5MPa·m. 1 / 2 The resistivity is 10 4 ~10 14 Ω·cm, thermal conductivity is 150~200W / (m·K).

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