Medium and low temperature aluminum nitride ceramic heater and preparation method thereof

Abstract

The invention discloses a medium-low temperature aluminum nitride ceramic heater and a preparation method thereof. The medium-low temperature aluminum nitride ceramic heater comprises an aluminum nitride ceramic substrate and a metal water-cooling base or a ceramic connecting support body which are sequentially arranged from top to bottom, wherein the metal water-cooling base or the ceramic connecting support body is used for supporting the aluminum nitride ceramic substrate; the aluminum nitride ceramic matrix is prepared from the following raw materials in percentage by mass: 85-95% of aluminum nitride, 3-5% of yttrium oxide, 0-10% of titanium nitride, 0-10% of titanium diboride, 0-5% of silicon carbide, 0-5% of tungsten carbide and 0-5% of titanium dioxide. According to the aluminum nitride ceramic heater, the formula of the aluminum nitride ceramic matrix of the aluminum nitride ceramic heater is optimized, other materials such as yttrium oxide, titanium nitride, titanium diboride, silicon carbide, tungsten carbide and titanium dioxide are introduced, and the content of each component is changed through formula blending, so that the purpose of performance optimization is achieved; the volume resistivity of the aluminum nitride ceramic heater in the medium and low temperature environment is effectively reduced, the adsorption force in the machining process is guaranteed to meet the requirement, the preparation technology is simple, operation is easy to control, and industrial production is facilitated.

Description

A medium-low temperature aluminum nitride ceramic heater and its preparation method Technical Field

[0001] This invention relates to the field of semiconductor ceramics, and in particular to a medium-low temperature aluminum nitride ceramic heater and its preparation method. Background Technology

[0002] Physical vapor deposition (PVD) is a technique that transforms solid materials into a gaseous state through physical processes, and then deposits them onto a substrate surface to form a thin film. Under vacuum conditions, the material is transformed into gaseous atoms or molecules by the action of high temperature or high-energy particles. The gaseous atoms or molecules are transported in the vacuum environment and eventually deposited onto the substrate surface. This process requires precise control of pressure and temperature to ensure the uniformity and adhesion of the film.

[0003] Wafer bonding technology refers to the process of tightly joining two mirror-polished homogeneous or heterogeneous wafers together through chemical and physical interactions. After bonding, the atoms at the interface react under external forces to form covalent bonds, achieving a specific bonding strength at the interface. Compared to traditional soldering and bonding methods, wafer bonding typically operates at lower temperatures and pressures, which helps protect the internal structure and performance of the wafer.

[0004] In physical vapor deposition and wafer bonding processes, aluminum nitride heaters provide adsorption and heating. At medium to low temperatures (200-350℃), the volume resistivity of ordinary aluminum nitride heaters exceeds 10⁻⁶. 11 The volume resistivity of Ω•cm is relatively high, which leads to poor adsorption, failure to adhere to the substrate / wafer, slippage, and wafer detachment, affecting the normal operation of PVD equipment and wafer bonding equipment.

[0005] Therefore, it is necessary to design a new aluminum nitride ceramic heater to solve the above problems. Summary of the Invention

[0006] In view of this, the present invention addresses the deficiencies of the existing technology, and its main objective is to provide a medium-low temperature aluminum nitride ceramic heater and its preparation method. By modifying the material formulation to achieve modification, it effectively solves the problem of excessively high volume resistivity in existing aluminum nitride heaters at medium and low temperatures, reducing the volume resistivity to within 10-1. 8 -10 10 The adsorption force is measured in Ω·cm to ensure that the adsorption force meets the requirements during the processing. The method of this invention is simple, easy to operate, and conducive to large-scale production.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a medium-low temperature aluminum nitride ceramic heater, comprising an aluminum nitride ceramic substrate arranged sequentially from top to bottom and a metal water-cooled base or ceramic connecting support body providing support for the aluminum nitride ceramic substrate; the aluminum nitride ceramic substrate is prepared from the following raw materials by mass percentage: aluminum nitride 85%-95%, yttrium oxide 3-5%, titanium nitride 0-10%, titanium diboride 0-10%, silicon carbide 0-5%, tungsten carbide 0-5%, and titanium dioxide 0-5%.

[0008] As a preferred embodiment, the aluminum nitride ceramic substrate is internally provided with a resistive heating element circuit for heating.

[0009] As a preferred embodiment, the heater is provided with electrodes / leads at its edge, which are connected to the two ends of the internal resistive heating element circuit.

[0010] As a preferred embodiment, the heater is an aluminum nitride ceramic heater with a metal water-cooled base. The aluminum nitride ceramic substrate has a resistive heating element circuit for heating inside. The lower surface of the aluminum nitride ceramic substrate is connected to the metal water-cooled base by solder. The metal water-cooled base has a cooling water channel inside.

[0011] As a preferred embodiment, the heater is an aluminum nitride ceramic heater with a ceramic connecting support. The interior of the aluminum nitride ceramic substrate is provided with a resistive heating element circuit for heating, and the lower surface of the aluminum nitride ceramic substrate is connected to the ceramic connecting support by solder.

[0012] A method for preparing a medium-low temperature aluminum nitride ceramic heater includes the following steps: (1) Preparation of slurry: The raw materials for preparing the aluminum nitride ceramic matrix are mixed in a certain proportion, and solvent and dispersant are added and put into a ball mill containing alumina balls for ball milling. Then, binder and plasticizer are added to the ball mill and ball milling is continued to obtain a uniformly mixed granulated slurry; (2) Granulation: The mixed granulated slurry is granulated into granulated powder using a granulator and sieved and batched using a vibrating screen; (3) Debinding: The obtained granulated powder is poured into a mold and placed in a debinding furnace to remove organic matter from the granulated powder; (4) Hot pressing: A fixed weight of aluminum nitride granulated powder is filled into a graphite mold, and heating and adsorption functional bodies are placed in sequence. (5) Machining: The ceramic sintered parts are finally processed by double-sided grinding and machining equipment to obtain aluminum nitride ceramic matrix; (6) Brazing: The aluminum nitride ceramic matrix and the metal water-cooled base or ceramic connecting support are connected together by solder and placed in a brazing furnace for heat preservation to obtain ceramic brazed parts; (7) Surface treatment: The ceramic brazed parts are thinned, polished and sandblasted to prepare surface gas flow grooves and high gloss sealing strips for gas sealing; (8) Cleaning: The surface-treated workpiece is cleaned to obtain a medium and low temperature aluminum nitride ceramic heater.

[0013] As a preferred embodiment, in step (1), the raw materials of the aluminum nitride ceramic matrix include one or more of aluminum nitride, yttrium oxide, titanium nitride, titanium diboride, silicon carbide, tungsten carbide, and titanium dioxide.

[0014] As a preferred embodiment, in step (1), the solvent is ethanol; the dispersant is at least one of castor oil, fish oil, polyethylene glycol, and phosphate ester; the binder is polyvinyl butyral; and the plasticizer is at least one of dioctyl phthalate, dimethyl phthalate, dibutyl phthalate, and diisononyl phthalate.

[0015] As a preferred embodiment, in step (7), the ceramic brazed part is ground to the required size by a ceramic thinning machine to obtain a ceramic thinned part; the ceramic thinned part is polished for 4 hours by a cloth polishing machine and alumina polishing liquid with a weight of 15-30kg to obtain a ceramic polished part with a ceramic surface roughness of <0.1μm; the ceramic polished part is then processed by a sandblasting process, using compressed air as power to form a high-speed jet beam, which sprays the abrasive material at high speed onto the surface of the workpiece to be treated, to prepare surface gas flow grooves and a high-gloss sealing strip for gas sealing.

[0016] As a preferred embodiment, the polishing fluid is nano-alumina powder abrasive, and the abrasive is 300-600 mesh high-purity corundum sand.

[0017] The prepared low-temperature aluminum nitride ceramic heater was subjected to performance tests, including the following tests: (1) Adsorption force test: The aluminum nitride heater sample was powered by a DC high voltage power supply, and its adsorption force was tested using a precision digital display tensile tester under ±800V conditions; the test wafer was firmly mounted on the aluminum nitride heater, ensuring that its axis coincided with the axis of the tensile sensor and that the end face was absolutely horizontal. The test speed, contact force and other parameters were set, the program was started, the measured force-displacement curve was recorded, and the maximum adsorption force was obtained.

[0018] (2) Temperature uniformity test: The aluminum nitride heater was installed in the vacuum water-cooled chamber, and the TC wafer was laid flat on the surface of the aluminum nitride heater. The thermocouple cable was led out and connected to the external data acquisition unit through the vacuum feedthrough interface. After the preparation work was completed, the heater was set to 350°C through the temperature controller and heated at a slow heating rate to avoid thermal shock. When the controller showed that the temperature had reached the set value and stabilized, the data was recorded.

[0019] (3) Leakage current test: Use a precision withstand voltage tester to test its leakage current; connect the test leads correctly, with the high voltage output terminal (HV) connected to the DC positive terminal of the device under test, and the ground terminal (GND) connected to the DC negative terminal of the device under test. Set the test parameters: Select the DC test mode, set the required DC high voltage value, boost rate and test time, and start the test. During the voltage stabilization stage, the steady-state current value measured by the instrument is the DC leakage current.

[0020] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution, the present invention optimizes the formulation of the aluminum nitride ceramic matrix of the aluminum nitride ceramic heater, introduces other materials such as yttrium oxide, titanium nitride, titanium diboride, silicon carbide, tungsten carbide, and titanium dioxide, and changes the content of each component through formulation adjustment to achieve the purpose of performance optimization. It effectively reduces the volume resistivity of the aluminum nitride ceramic heater in medium and low temperature environments, so as to ensure that the adsorption force during the processing meets the requirements. The preparation process is simple, easy to operate and control, and conducive to industrial production.

[0021] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0022] Figure 1 is a cross-sectional view of the aluminum nitride ceramic heater with a metal cooling water base according to the present invention; Figure 2 is a cross-sectional view of the aluminum nitride ceramic heater with a ceramic connecting support according to the present invention.

[0023] Explanation of the symbols in the attached diagram: 1. Heating wire; 2. Aluminum nitride ceramic substrate; 3. Ceramic connecting support; 4. Metal water-cooled base; 5. Cooling water channel. Detailed Implementation

[0024] This invention discloses a medium-low temperature aluminum nitride ceramic heater, comprising an aluminum nitride ceramic substrate 2 arranged sequentially from top to bottom, and a metal water-cooled base 4 or a ceramic connecting support 3 providing support for the aluminum nitride ceramic substrate 2. The aluminum nitride ceramic substrate 2 is prepared from the following raw materials by mass percentage: aluminum nitride 85%-95%, yttrium oxide 3-5%, titanium nitride 0-10%, titanium diboride 0-10%, silicon carbide 0-5%, tungsten carbide 0-5%, and titanium dioxide 0-5%. The interior of the aluminum nitride ceramic substrate 2 is provided with a resistive heating element circuit for heating, which is a heating wire 1. Electrodes / leads (not shown in the figure) are provided at the edge of the heater, and these electrodes / leads are connected to both ends of the internal resistive heating element circuit.

[0025] As shown in Figure 1, the heater is an aluminum nitride ceramic heater with a metal water-cooled base 4. The aluminum nitride ceramic substrate 2 has a resistive heating element circuit for heating inside. The lower surface of the aluminum nitride ceramic substrate 2 is connected to the metal water-cooled base 4 by solder. The metal water-cooled base has a cooling water channel 5 inside.

[0026] As shown in Figure 2, the heater is an aluminum nitride ceramic heater with a ceramic connecting support 3. The aluminum nitride ceramic substrate 2 has a resistive heating element circuit for heating inside. The lower surface of the aluminum nitride ceramic substrate 2 is connected to the ceramic connecting support 3 by solder.

[0027] The present invention also discloses a method for preparing a medium-low temperature aluminum nitride ceramic heater, comprising the following steps: (1) Preparation of slurry: The raw materials for preparing aluminum nitride ceramic matrix 2 are mixed in a certain proportion, and the components are aluminum nitride (AlN), yttrium oxide (Y2O3), titanium nitride (TiN), titanium diboride (TiB2), silicon carbide (SiC), tungsten carbide (WC), and titanium dioxide (TiO2), with a particle size of 1.3-1.8μm. The raw materials are weighed accurately in a certain proportion, and based on the powder mass, 67-85 parts by weight of solvent and 1-3 parts by weight of dispersant are added to a ball mill containing 150-200 parts by weight of alumina balls with a particle size of 5-15mm. The mixture is processed at a speed of 40-70r / min for 24 hours. Then, 0.5-3 parts by weight of binder and 4-8 parts by weight of plasticizer are added to the ball mill, and the mixture is ball-milled for another 24 hours to obtain a uniformly mixed granulated slurry.

[0028] (2) Granulation: The mixed granulation slurry is granulated using a granulator to obtain granulated powder with a particle size of 80-150μm, and then sieved and batched using a vibrating screen.

[0029] (3) Debinding: Pour the obtained granulated powder into the mold and place it in the debinding furnace. Keep it at 500-600℃ for 4-6 hours to remove organic matter from the granulated powder.

[0030] (4) Hot pressing: A fixed weight of aluminum nitride granulated powder is filled into the graphite mold. The heating and adsorption functional bodies are placed into the graphite mold in sequence, and the two are separated by the granulated powder after debinding. The graphite mold is placed in the hot pressing sintering furnace for sintering. The temperature is maintained at 1800-1850℃ and 35MPa for 5-6 hours to obtain ceramic sintered parts.

[0031] (5) Machining: The sintered ceramic parts are finally processed by double-sided grinding and machining equipment to obtain an aluminum nitride ceramic matrix 2 with a flatness of <5μm and a surface roughness of less than 0.1μm.

[0032] (6) Brazing: The aluminum nitride ceramic substrate 2 and the metal water-cooled base 4 or the ceramic connecting support 3 are connected together by solder, placed in a brazing furnace, and kept at 1100℃±50℃ for 1 hour to obtain the ceramic brazed part.

[0033] (7) Surface treatment: The ceramic brazed parts are ground to the required dimensions using a ceramic thinning machine to obtain ceramic thinned parts. The ceramic thinned parts are then polished for 4 hours using a cloth polishing machine and alumina polishing liquid with a counterweight of 15-30 kg to obtain polished parts with a ceramic surface roughness of <0.1μm. The polished ceramic parts are then subjected to a sandblasting process, using compressed air to form a high-speed jet beam, which sprays 300-600 mesh high-purity corundum abrasive onto the surface of the workpiece to be treated, creating surface gas flow grooves and a high-gloss sealing strip for gas sealing.

[0034] (8) Cleaning: Clean the surface-treated workpiece by placing it in an ultrasonic cleaner, pouring in nano alumina powder abrasive, and cleaning at a low frequency of 28kHz; then, use high frequency 40kHz ultrasonic cleaning to remove more microscopic and fine impurity particles.

[0035] Further, in step (1), the solvent is ethanol; the dispersant is at least one of castor oil, fish oil, polyethylene glycol and phosphate ester; the binder is polyvinyl butyral; and the plasticizer is at least one of dioctyl phthalate, dimethyl phthalate, dibutyl phthalate and diisononyl phthalate.

[0036] Furthermore, in step (1), the optimal proportion of the solvent is 70 parts by weight; the optimal proportion of the dispersant is 2 parts by weight; and the optimal proportion of the binder is 2 parts by weight.

[0037] Furthermore, in step (7), the mechanical properties of the workpiece surface are improved by sandblasting, which increases the fatigue strength of the workpiece, increases the adhesion between it and the coating, prolongs the durability of the coating film, and also facilitates the leveling and decoration of the coating.

[0038] Furthermore, in step (1), the aluminum nitride ceramic raw materials contain the following weight percentages: aluminum nitride (AlN) 85%-95%, yttrium oxide (Y2O3) 3-5%, titanium nitride (TiN) 0-10%, titanium diboride (TiB2) 0-10%, silicon carbide (SiC) 0-2%, tungsten carbide (WC) 0-2%, and titanium dioxide (TiO2) 0-1%. The various formulations of the raw materials for the aluminum nitride ceramic matrix 2 are shown in the table below: Table 1: Detailed Formulation of Raw Materials for the Aluminum Nitride Ceramic Matrix

[0039] The test results of the properties of aluminum nitride ceramic raw materials with different formulations after machining in step (5) are shown in the table below: Table 2 Test results of the properties of raw material formulations of different aluminum nitride ceramic matrices after machining

[0040] Performance tests conducted on machined raw material formulations of different aluminum nitride ceramic matrices revealed that the introduction of materials such as titanium nitride, titanium diboride, silicon carbide, tungsten carbide, and titanium dioxide contributes to the optimization of ceramic properties, effectively reducing volume resistivity and improving flexural strength and dielectric constant. However, these materials also affect certain properties such as thermal conductivity, dielectric loss, and breakdown strength. Therefore, formulation optimization is necessary to ensure the appropriate introduction of these materials.

[0041] Among the raw material formulations for different aluminum nitride ceramic matrices, formulation 6-10 is preferred. Performance tests were conducted on products made from formulation 6-10, and the results are shown in Table 3 below: Table 3 Performance Test Results of Products Processed from Raw Material Formulations of Different Aluminum Nitride Ceramic Matrices

[0042] The performance test results of the products processed by different aluminum nitride ceramic raw material formulations show that the ceramic raw material formulation of Scheme 8 is the optimal formulation, which can effectively improve the ceramic adsorption force, enhance temperature uniformity, and reduce leakage current. The processed aluminum nitride heater has an adsorption force of 3867gf under DC high voltage power supply, a temperature uniformity of 3.8℃ at 350℃, and a leakage current of 0.43mA.

[0043] Scheme 8, consisting of 90% aluminum nitride (AlN), 5% yttrium oxide (Y2O3), 1.7% titanium nitride (TiN), 1.5% titanium diboride (TiB2), 1% silicon carbide (SiC), 0.5% tungsten carbide (WC), and 0.3% titanium dioxide (TiO2), is the optimal implementation scheme.

[0044] The key design focus of this invention is: by optimizing the formulation of the aluminum nitride ceramic matrix of the aluminum nitride ceramic heater, introducing other materials such as yttrium oxide, titanium nitride, titanium diboride, silicon carbide, tungsten carbide, and titanium dioxide, and by adjusting the formulation to change the content of each component, the performance is optimized. This effectively reduces the volume resistivity of the aluminum nitride ceramic heater in medium and low temperature environments, ensuring that the adsorption force during processing meets the requirements. The preparation process is simple, easy to operate and control, and conducive to industrial production.

[0045] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A medium-low temperature aluminum nitride ceramic heater, characterized in that: It includes an aluminum nitride ceramic matrix arranged from top to bottom and a metal water-cooled base or ceramic connecting support body that provides support for the aluminum nitride ceramic matrix; the aluminum nitride ceramic matrix is ​​prepared from the following raw materials in the following mass percentages: aluminum nitride 85%-95%, yttrium oxide 3-5%, titanium nitride 0-10%, titanium diboride 0-10%, silicon carbide 0-5%, tungsten carbide 0-5%, and titanium dioxide 0-5%.

2. The medium-low temperature aluminum nitride ceramic heater as described in claim 1, characterized in that: The aluminum nitride ceramic matrix has a resistive heating element circuit inside for heating.

3. A medium-low temperature aluminum nitride ceramic heater as described in claim 2, characterized in that: The heater is provided with electrodes / leads at its edge, which are connected to the two ends of the internal resistive heating element circuit.

4. A medium-low temperature aluminum nitride ceramic heater as described in claim 1, characterized in that: The heater is an aluminum nitride ceramic heater with a metal water-cooled base. The aluminum nitride ceramic substrate has a resistive heating element circuit for heating inside. The lower surface of the aluminum nitride ceramic substrate is connected to the metal water-cooled base by solder. The metal water-cooled base has a cooling water channel inside.

5. A medium-low temperature aluminum nitride ceramic heater as described in claim 1, characterized in that: The heater is an aluminum nitride ceramic heater with a ceramic connecting support. The interior of the aluminum nitride ceramic substrate is provided with a resistive heating element circuit for heating. The lower surface of the aluminum nitride ceramic substrate is connected to the ceramic connecting support by solder.

6. A method for preparing a medium-low temperature aluminum nitride ceramic heater as described in any one of claims 1-5, characterized in that: Includes the following steps: (1) Preparation of slurry: The raw materials for preparing aluminum nitride ceramic matrix are mixed in a certain proportion, and solvent and dispersant are added and put into a ball mill containing alumina balls for ball milling. Then, binder and plasticizer are added to the ball mill and ball milling is continued to obtain a uniformly mixed granulated slurry; (2) Granulation: The mixed granulated slurry is granulated into granulated powder using a granulator and sieved and batched using a vibrating screen; (3) Debinding: The obtained granulated powder is poured into a mold and placed in a debinding furnace to remove organic matter from the granulated powder; (4) Hot pressing: A fixed weight of aluminum nitride granulated powder is filled into a graphite mold, and the heating and adsorption functional bodies are placed into the graphite mold in sequence. Debinding is used between the two. After the granulation powder is separated, the graphite mold is placed in the hot pressing sintering furnace for sintering to obtain ceramic sintered parts; (5) Machining: the ceramic sintered parts are finally processed by double-sided grinding and machining equipment to obtain aluminum nitride ceramic matrix; (6) Brazing: the aluminum nitride ceramic matrix and the metal water-cooled base or ceramic connecting support are connected together by solder and placed in the brazing furnace for heat preservation to obtain ceramic brazed parts; (7) Surface treatment: the ceramic brazed parts are thinned, polished and sandblasted to prepare surface gas flow grooves and high gloss sealing strips for gas sealing; (8) Cleaning: the surface-treated workpiece is cleaned to obtain a medium and low temperature aluminum nitride ceramic heater.

7. The method for preparing a medium-low temperature aluminum nitride ceramic heater as described in claim 6, characterized in that: In step (1), the raw materials of the aluminum nitride ceramic matrix include one or more of aluminum nitride, yttrium oxide, titanium nitride, titanium diboride, silicon carbide, tungsten carbide, and titanium dioxide.

8. The method for preparing a medium-low temperature aluminum nitride ceramic heater as described in claim 6, characterized in that: In step (1), the solvent is ethanol; the dispersant is at least one of castor oil, fish oil, polyethylene glycol, and phosphate ester; and the binder is polyvinyl butyral. The plasticizer is at least one of dioctyl phthalate, dimethyl phthalate, dibutyl phthalate, and diisononyl phthalate.

9. The method for preparing a medium-low temperature aluminum nitride ceramic heater as described in claim 6, characterized in that: In step (7), the ceramic brazed parts are ground to the required dimensions by a ceramic thinning machine to obtain ceramic thinned parts; the ceramic thinned parts are polished for 4 hours by a cloth polishing machine and alumina polishing liquid with a weight of 15-30kg to obtain ceramic polished parts with a ceramic surface roughness of <0.1μm; This ceramic polishing part uses a sandblasting process, which uses compressed air to form a high-speed jet beam, and sprays the abrasive material at high speed onto the surface of the workpiece to be treated, creating surface gas flow grooves and a high-gloss sealing strip for gas sealing.

10. The method for preparing a medium-low temperature aluminum nitride ceramic heater as described in claim 9, characterized in that: The polishing fluid is nano-alumina powder abrasive, and the abrasive is 300-600 mesh high-purity corundum sand.

Images