Electrostatic chuck with microelectrodes and processing method

Abstract

The application relates to the technical field of semiconductor electrostatic chucks, in particular to an electrostatic chuck ceramic plate with microelectrodes and a processing method, and the specific steps include the following: determining a ceramic layer electrode forming surface and arranging a conductive layer, coating photoresist and drying, exposing and developing to form a reserved area and an etching area, etching and removing the photoresist to form an electrode base layer, electroplating and thickening after cleaning to form microelectrodes, and finally performing surface treatment on the microelectrodes. The method replaces the traditional process with a complete process, significantly improves the forming precision of the microelectrodes, solves the high-density integration problem of functional electrodes by layering and independently processing the electrostatic, temperature sensing and heating layer plates and then bonding, can realize accurate control of multiple temperature zones, is coherent in process, has strong operability, guarantees the quality of the microelectrodes, improves the chuck adsorption and temperature control performance, is suitable for semiconductor etching and other processes, and has practicality and industrial mass production value.

Description

Technical Field

[0001] This invention relates to the field of semiconductor electrostatic chuck technology, specifically to an electrostatic chuck with microelectrodes and its processing method. Background Technology

[0002] Electrostatic chucks (ESCs or E-CHUCKs) are used in semiconductor manufacturing processes to hold and support wafers. They utilize electrostatic adsorption to hold the wafer to be processed on their surface, preventing movement or misalignment during production. They are widely used in processes such as physical vapor deposition (PVD), chemical vapor deposition (CVD), and etching.

[0003] The main drawback of existing technology is that: Conventional electrostatic adsorption chucks use electrodes formed through machining, welding, or traditional printing processes to perform electrostatic, heating, and temperature sensing functions. These electrodes are relatively large and have low precision. The use of large electrodes or bulk materials makes it impossible to make the electrode patterns very small, which limits the electrode layout density and precision, and consequently affects the temperature control performance and functionality of the chuck. Furthermore, existing technologies struggle to integrate multiple functional electrodes at a high density within a limited plane. For instance, it is impossible to fabricate temperature sensing sensor electrodes and heating electrodes together at a high density, thus limiting the chuck's ability to achieve independent and precise control of multiple temperature zones.

[0004] Therefore, there is an urgent need to provide a solution to overcome the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide an electrostatic chuck with microelectrodes and a processing method thereof. The process is continuous, highly operable, ensures the quality of the microelectrodes, improves the adsorption and temperature control performance of the chuck, and is compatible with processes such as semiconductor etching. It has both practicality and industrial mass production value.

[0006] To achieve the above objectives, the present invention provides the following technical solution; A method for fabricating an electrostatic chuck with microelectrodes includes a ceramic chuck and a chuck base composed of an electrostatic layer, a temperature-sensing layer, and a heating layer. The ceramic chuck is mounted on the chuck base. The electrostatic layer, temperature-sensing layer, and heating layer are all ceramic layers, and microelectrodes are disposed on the ceramic layers. The microelectrodes have a linewidth of 5-50 μm and a line spacing of 10-100 μm, achieving a high-density layout. The specific steps are as follows: S10. Determine the electrode forming surface of the ceramic layer, and set a conductive layer on the entire electrode forming surface; S20. Coat a designated area on the conductive layer with photoresist and bake and dry it; S30. Expose and develop the photoresist coated on the conductive layer to form a retention area covered with photoresist of a predetermined electrode pattern and an etched area without photoresist coverage; S40. Etch away the etched area of ​​the conductive layer, and remove the photoresist from the retention area on the conductive layer to form an electrode base layer with a predetermined pattern; S50. Clean the entire ceramic layer after photoresist removal to remove residual photoresist and cleaning solution; perform electroplating thickening treatment on the electrode base layer on the electrode forming surface to form a thickened layer, and the thickened layer and the electrode base layer form a microelectrode; S60. Perform surface treatment on the microelectrode on the electrode forming surface.

[0007] After the electrostatic layer, temperature-sensing layer, and heating layer are independently processed into shaped microelectrodes according to the above steps S10 to S60, they are subjected to interlayer bonding treatment to form a ceramic plate. The ceramic plate is then installed with the chuck base to form an electrostatic chuck.

[0008] Furthermore, in S10, the conductive layer is set by sputtering deposition, and the material is a titanium-copper composite layer or a chromium-copper composite layer. The total thickness of the conductive layer is 150-700nm, of which the bottom layer is a titanium layer or chromium layer of 50-200nm and the top layer is a copper layer of 100-500nm. Before setting the conductive layer, the electrode forming surface of the ceramic layer is first cleaned and activated.

[0009] Furthermore, S20 also includes: S21. Applying positive photoresist to a designated area of ​​the conductive layer, with a photoresist thickness of 10-25 μm; S22. Drying the conductive layer after photoresist application with hot air at a temperature of 80-120°C for 15-30 minutes.

[0010] Furthermore, S30 also includes: S31. Exposing the photoresist to ultraviolet light using a mask, with an exposure dose of 100-200 mJ / cm² and an exposure time of 30-60 s. For every 5 μm increase in photoresist thickness, the exposure time is increased by 10 s. The mask pattern is consistent with the design pattern of the microelectrode to ensure that the reserved area is completely matched with the predetermined electrode pattern. S32. Immersing the exposed ceramic layer in 2.38% TMAH developing solution for development treatment, with a development temperature of 20-25℃ and a development time of 60-120 s.

[0011] Furthermore, in step S40, the etching depth is consistent with the total thickness of the conductive layer. The photoresist removal process uses 5%-10% dilute hydrochloric acid for etching and cleaning at room temperature for 10-30 seconds to remove surface metal oxides and loosen the photoresist edges. Then, the photoresist is removed by soaking in N-methylpyrrolidone swelling solution at 40-50°C for 5-10 minutes, combined with ultrasonic oscillation. The soaking temperature is 40-60°C, and the processing time is 10-30 minutes. The organic solvent is selected from one or a mixture of N-methylpyrrolidone, dimethyl sulfoxide, or acetone.

[0012] Furthermore, S50 also includes: S51. Surface activation of the ceramic layer after adhesive removal by plasma cleaning for 3-10 minutes; S52. Ultrasonic cleaning with anhydrous ethanol and deionized water in sequence for 5-10 minutes each to remove organic residues and ionic contamination; S53. Electroplating thickening treatment with electrode base layer 131 as cathode, using nickel or nickel-copper alloy as the electroplating metal, with an electroplating thickness of 5-30 μm.

[0013] Furthermore, the surface treatment of S60 includes passivation and polishing. The passivation treatment forms a passivation film on the surface of the microelectrode with a thickness of 5-15 nm; the polishing treatment makes the surface roughness of the microelectrode ≤0.1 μm.

[0014] Furthermore, the ceramic layer is alumina ceramic, and the microelectrode pattern is concentric circles, comb-like, or grid-like, with a layout density of ≥100 electrodes / cm². A thin-film temperature sensor is also integrated on the surface of the microelectrode of the temperature-sensing layer. The thin-film temperature sensor adopts a platinum resistance or thermocouple structure and is integrated with the microelectrode by sputtering deposition. The sensor accuracy is ≤±0.1℃.

[0015] Furthermore, a thin-film temperature sensor is integrated on the surface of the microelectrode of the temperature-sensing layer. The thin-film temperature sensor adopts a platinum resistance or thermocouple structure and is integrated with the microelectrode by sputtering deposition. The sensor accuracy is ≤ ±0.1℃.

[0016] Furthermore, a method for processing an electrostatic chuck with microelectrodes also includes another specific step: S100. Determine the electrode forming surface of the ceramic layer, and set the electrode layer on the entire electrode forming surface using PVD process; S200. Coat a designated area on the electrode layer with photoresist and bake and dry it; S300. Expose and develop the photoresist coated on the electrode layer to form a retention area covered with photoresist of a predetermined electrode pattern and an etched area without photoresist coverage; S400. Etch and remove the etched area of ​​the electrode layer, and remove the photoresist from the retention area on the electrode layer to form a microelectrode with a predetermined pattern; S500. Clean the entire ceramic layer after photoresist removal to remove residual photoresist and cleaning solution; S600. Perform surface treatment on the microelectrode on the electrode forming surface.

[0017] Furthermore, a method for processing an electrostatic chuck with microelectrodes also includes another specific step: S1000. Determine the electrode forming surface of the ceramic layer, and set the electrode layer on the entire electrode forming surface using PVD process; S2000. Perform laser processing on a designated area on the electrode layer to remove part of the electrode layer according to a predetermined pattern to form a microelectrode; S3000. Perform surface treatment on the microelectrode on the electrode forming surface.

[0018] The present invention also provides an electrostatic chuck with microelectrodes, comprising a ceramic plate, wherein the ceramic plate comprises a heating layer, a temperature sensing layer and an electrostatic layer bonded from bottom to top; the heating layer, the temperature sensing layer and the electrostatic layer are all ceramic layers with microelectrodes, the interlayer bonding strength is ≥15MPa, the microelectrode bonding force is ≥10N / cm, and the high temperature resistance is ≥400℃.

[0019] Furthermore, a ceramic plate with microelectrodes is mounted on a chuck base to form an electrostatic chuck for electrostatic adsorption of sheet-like materials; the ceramic plate and the chuck base may be circular, rectangular or other irregular shapes.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention replaces traditional processes with a complete workflow of "conductive layer setup → adhesive coating and drying → exposure and development → etching and adhesive removal → cleaning and electroplating → surface treatment," significantly improving the precision of microelectrode forming. Simultaneously, by independently processing electrostatic, temperature-sensing, and heating microelectrodes in layers and then bonding them, it solves the challenge of high-density integration of multiple functional electrodes, enabling independent and precise control of multiple temperature zones. This method is process-coherent, highly operable, ensures microelectrode forming quality, improves the stability of electrostatic chuck adsorption and temperature control performance, adapts to the process requirements of semiconductor etching, and possesses both practicality and industrial mass production value. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the molding process in Embodiment 1 of the present invention.

[0022] Figure 2This is a schematic diagram of the multilayer ceramic layer in Embodiment 1 of the present invention.

[0023] Figure 3 This is a schematic diagram of the molding process in Embodiment 2 of the present invention. Figure 4 This is a schematic diagram of the molding process in Embodiment 3 of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example

[0025] refer to Figure 1-2 As shown, this invention provides a method for processing an electrostatic chuck with microelectrodes, comprising a ceramic chuck and a chuck base composed of an electrostatic layer, a temperature-sensing layer, and a heating layer. The ceramic chuck is mounted on the chuck base. The electrostatic layer, temperature-sensing layer, and heating layer are all ceramic layers, and microelectrodes are disposed on the ceramic layers. The microelectrodes have a linewidth of 5-50 μm and a line spacing of 10-100 μm, achieving a high-density layout. The specific steps are as follows: S10. Determine the electrode forming surface of the ceramic layer, and set a conductive layer on the entire electrode forming surface; S20. Coat a designated area on the conductive layer with photoresist and bake and dry it; S30. Expose and develop the photoresist coated on the conductive layer to form a retention area covered with photoresist of a predetermined electrode pattern and an etched area without photoresist coverage; S40. Etch away the etched area of ​​the conductive layer, and remove the photoresist from the retention area on the conductive layer to form an electrode base layer 131 with a predetermined pattern; S50. Clean the entire ceramic layer after photoresist removal to remove residual photoresist and cleaning solution; perform electroplating thickening treatment on the electrode base layer 131 on the electrode forming surface to form a thickened layer 132, and the thickened layer 132 and the electrode base layer 131 form a microelectrode; S60. Perform surface treatment on the microelectrode on the electrode forming surface.

[0026] After the electrostatic layer, temperature-sensing layer, and heating layer are independently processed into shaped microelectrodes according to the above steps S10 to S60, they are subjected to interlayer bonding treatment to form a ceramic plate. The ceramic plate is then installed with the chuck base to form an electrostatic chuck.

[0027] Specifically, the ceramic layer 1 has a thickness of 0.3-1mm, and the microelectrode 13 pre-set on its surface has a line width of 5-50μm and a line spacing of 10-100μm, achieving a high-density layout of microelectrodes.

[0028] This invention replaces traditional processes with a complete workflow of "conductive layer setup → adhesive coating and drying → exposure and development → etching and adhesive removal → cleaning and electroplating → surface treatment," significantly improving the precision of microelectrode forming. Simultaneously, by independently processing electrostatic, temperature-sensing, and heating microelectrodes in layers and then bonding them, it solves the challenge of high-density integration of multiple functional electrodes, enabling independent and precise control of multiple temperature zones. This method is process-coherent, highly operable, ensures microelectrode forming quality, improves the stability of electrostatic chuck adsorption and temperature control performance, adapts to the process requirements of semiconductor etching, and possesses both practicality and industrial mass production value.

[0029] In this embodiment, in step S10, the conductive layer 12 is set by sputtering deposition and is made of titanium-copper composite layer or chromium-copper composite layer. The total thickness of the conductive layer 12 is 150-700nm, of which the bottom layer is a titanium layer or chromium layer of 50-200nm and the top layer is a copper layer of 100-500nm. Before setting the conductive layer 12, the electrode forming surface 11 of the ceramic layer 1 is cleaned and activated.

[0030] Specifically, before setting the conductive layer 12, the electrode forming surface 11 of the ceramic layer 1 undergoes a combination of plasma cleaning and colloidal palladium activation. The plasma cleaning power is 100-200W, and the processing time is 5-8 minutes, effectively removing impurities such as oil, dust, and oxides from the forming surface and increasing surface roughness. Colloidal palladium activation uses a colloidal palladium solution with a concentration of 0.5-1g / L, immersing at room temperature for 3-5 minutes to introduce catalytically active sites on the ceramic surface. The conductive layer 12 is prepared by magnetron sputtering deposition, using a titanium-copper composite layer or a chromium-copper composite layer, with a total thickness controlled at 150-700nm. The bottom layer is a 50-200nm titanium or chromium layer, and the top layer is a 100-500nm copper layer. Argon gas is introduced as a protective gas during sputtering, with a flow rate of 20-50sccm, to ensure uniform deposition of the conductive layer without pinholes or defects. This embodiment supplements the specific methods, parameters, and protective gas requirements for cleaning and activation, and improves the process details of conductive layer preparation. The titanium / chromium underlayer can significantly improve the adhesion between the conductive layer and the alumina ceramic layer, preventing the conductive layer from falling off in subsequent processes. The copper surface layer has excellent conductivity, providing a good conductive substrate for etching and electroplating thickening. The pretreatment process effectively improves the interfacial bonding performance between the ceramic surface and the conductive layer, ensuring that the conductive layer is firmly deposited, laying the foundation for the precise forming of subsequent microelectrodes, and reducing process defects.

[0031] In this embodiment, S20 further includes: S21. Selecting positive photoresist 2 to coat a designated area of ​​the conductive layer 12, the thickness of the photoresist 2 being 10-25μm; S22. Drying the conductive layer 12 after coating with photoresist 2 with hot air, the hot air temperature being 80-120℃, and the drying time being 15-30min.

[0032] Specifically, photoresist 2 is spin-coated onto a designated area of ​​conductive layer 12 at a spin speed of 3000-5000 r / min, forming a uniform photoresist layer with a thickness of 10-25 μm, free of runs and pinholes. The coated ceramic layer 1 is then placed in a hot air drying oven for baking, with the hot air temperature precisely controlled at 80-120℃ for 15-30 minutes. A stepped heating method is used during drying to prevent bubbles and edge lifting caused by sudden temperature changes. This embodiment supplements the specific coating method and heating process for photoresist, refining the operational details of coating and drying. The selection of a positive photoresist is suitable for the fine patterning requirements of microelectrodes. The spin-coating method ensures uniform photoresist thickness, and the stepped heating drying ensures a strong bond between the photoresist and the conductive layer, eliminating defects such as bubbles and edge lifting. This effectively prevents pattern distortion and photoresist peeling during subsequent exposure and development, ensuring the accuracy of photolithography and providing excellent photoresist protection for precise etching of the microelectrodes.

[0033] In this embodiment, step S30 further includes: S31. Exposing the photoresist 2 to ultraviolet light using a mask, with an exposure dose of 100-200 mJ / cm² and an exposure time of 30-60 s. For every 5 μm increase in the thickness of the photoresist 2, the exposure time is increased by 10 s. The mask pattern is consistent with the design pattern of the microelectrode 13 so that the reserved area 14 is completely matched with the predetermined electrode pattern. S32. Immersing the exposed ceramic layer 1 in 2.38% TMAH developing solution for developing, with a developing temperature of 20-25°C and a developing time of 60-120 s.

[0034] Specifically, a quartz mask matching the design pattern of microelectrode 13 in a 1:1 ratio is used to expose photoresist 2 to ultraviolet light. The exposure light source is 365nm ultraviolet light, the exposure dose is controlled at 100-200mJ / cm², and the basic exposure time is 30-60s. The exposure time is flexibly adjusted according to the principle of "increasing the exposure time by 10s for every 5μm increase in photoresist thickness" to ensure that the photoresist exposure area is fully exposed to light. After exposure, ceramic layer 1 is immersed in 2.38% TMAH developer for development. The development temperature is 20-25℃, and the development time is 60-120s. A gentle stirring method is used during the development process to accelerate the dissolution of the photoresist layer in the exposure area. This embodiment has no missing process details and requires no additional supplementation; standardized exposure parameters ensure that the mask pattern is accurately transferred to the photoresist layer, and the temperature and time control of development ensure that the photoresist layer in the exposed area is completely dissolved, while the photoresist layer in the unexposed area is completely preserved. The retained area 14 formed after development is completely matched with the predetermined electrode pattern, and the conductive layer in the etched area 15 is completely exposed with no residual photoresist, clear boundaries and vertical sidewalls, which ensures the accuracy of subsequent etching steps and improves the pattern forming accuracy of the microelectrode.

[0035] In this embodiment, in step S40, the etching depth is consistent with the total thickness of the conductive layer 12. The photoresist removal process uses 5%-10% dilute hydrochloric acid for etching and cleaning at room temperature for 10-30 seconds to remove surface metal oxides and loosen the photoresist edges. Then, the photoresist is removed by soaking in N-methylpyrrolidone swelling solution at 40-50°C for 5-10 minutes, combined with ultrasonic oscillation. The soaking temperature is 40-60°C, and the processing time is 10-30 minutes. The organic solvent is selected from one or more mixed solutions of N-methylpyrrolidone, dimethyl sulfoxide, or acetone.

[0036] Specifically, the etching process employs a wet etching method. For the titanium-copper / chromium-copper composite conductive layer, a matching etching solution system is selected. First, a fluoride etching solution is used to etch the titanium / chromium underlayer, and then an acidic etching solution is used to etch the copper surface layer. The etching process is carried out at room temperature. By controlling the etching time, it is ensured that the etching depth is completely consistent with the total thickness of the conductive layer 12. Only the conductive layer in the etched area 15 is removed without damaging the surface of the underlying ceramic layer 1. After etching, there is no conductive layer residue in the etched area. The photoresist removal process strictly follows the steps of "weak acid cleaning - swelling - ultrasonic removal with organic solvent". After cleaning with 5-10% dilute hydrochloric acid at room temperature for 10-30 seconds, the photoresist is immersed in N-methylpyrrolidone swelling solution at 40-50℃ for 5-10 minutes to fully swell and soften it. Then, it is immersed in an organic solvent at 40-60℃ with a volume ratio of N-methylpyrrolidone:acetone of 1:1, combined with ultrasonic vibration at 200-300W for 10-30 minutes to thoroughly remove residual photoresist. This embodiment supplements the specific etching method, etching solution type, and etching temperature requirements, thus improving the etching process. The wet etching method achieves precise removal of the conductive layer, avoiding damage to the ceramic substrate. The combined photoresist removal process effectively removes residual photoresist and loosens and removes metal oxides, ensuring that the 131 electrode base pattern is complete, the surface is clean, and there is no residual photoresist or oxide contamination after etching, providing a good electrode base for subsequent electroplating thickening.

[0037] In this embodiment, S50 further includes: S51. Surface activation of the ceramic layer 1 after adhesive removal by plasma cleaning for 3-10 minutes; S52. Ultrasonic cleaning with anhydrous ethanol and deionized water in sequence for 5-10 minutes each to remove organic residues and ionic contamination; S53. Electroplating thickening treatment with electrode base layer 131 as cathode, using nickel or nickel-copper alloy as the electroplating metal, with an electroplating thickness of 5-30 μm.

[0038] Specifically, the plasma cleaning of S51 uses oxygen plasma with a power of 100-200W and a processing time of 3-10 minutes to remove trace amounts of organic residue from the ceramic layer surface and the gap between the electrode substrate through plasma bombardment; the ultrasonic cleaning of S52 uses an ultrasonic cleaner with a power of 200-300W, with anhydrous ethanol and deionized water for 5-10 minutes each, and is then dried with nitrogen hot air at 80-100℃ to prevent oxidation of the ceramic layer and electrode substrate; the electroplating thickening of S53 uses a sulfate electroplating system, with electrode substrate 131 as the cathode and a nickel plate / nickel-copper alloy plate as the anode, the current density is controlled at 1-3A / dm², the electroplating metal is nickel or nickel-copper alloy with a nickel content of 80%-95%, the electroplating thickness is 5-30μm, and the surface of microelectrode 13 is flat after electroplating, with a flatness error of ≤2μm with the ceramic layer surface. This embodiment supplements the gas type and power for plasma cleaning, the power and drying method for ultrasonic cleaning, and also supplements the electroplating system, current density, and flatness requirements for the microelectrode after electroplating, thus improving the cleaning and electroplating processes. The multi-step combined cleaning achieves comprehensive cleaning of the ceramic layer and electrode base layer, with no residual adhesive, no organic residue, and no ion contamination. The standardized electroplating parameters ensure uniform microelectrode thickness and strong bonding. The nickel and nickel-copper alloy plating layers have good high-temperature resistance and corrosion resistance, making them suitable for the harsh environment of semiconductor production. Flatness control improves the surface compatibility of the electrostatic chuck.

[0039] In this embodiment, the surface treatment of S60 includes passivation treatment and polishing treatment. The passivation treatment forms a passivation film on the surface of the microelectrode 13 with a thickness of 5-15nm; the polishing treatment makes the surface roughness of the microelectrode 13 ≤0.1μm.

[0040] Specifically, the passivation treatment employs chemical passivation, immersing the ceramic layer 1 of the prepared microelectrode 13 in a chromate passivation solution at room temperature for 5-10 minutes to form a dense passivation film with a thickness of 5-15 nm on the microelectrode surface. The passivation film is uniform and free of pinholes. The polishing treatment employs chemical mechanical polishing, using a polyurethane polishing pad and an alkaline silica polishing solution. The polishing pressure is 0.5-1.0 psi. After polishing, the surface roughness of the microelectrode 13 is ≤0.1 μm, with no scratches or depressions. This embodiment supplements the specific methods and process parameters of passivation and polishing, improving the surface treatment process. The dense passivation film can effectively improve the corrosion resistance and oxidation resistance of the microelectrode, extending the service life of the electrostatic chuck. Chemical mechanical polishing makes the microelectrode surface highly flat, reducing contact resistance and improving the conductivity of the microelectrode. At the same time, the flat surface is more conducive to wafer adsorption and bonding, improving the adsorption stability of the electrostatic chuck.

[0041] In this embodiment, the ceramic layer 1 is alumina ceramic, and the microelectrode 13 has a pattern of concentric circles, comb-like teeth, or grid-like teeth, with a layout density of ≥100 electrodes / cm².

[0042] Specifically, ceramic layer 1 is made of alumina ceramic with a purity of ≥96%. This material has excellent high-temperature insulation, thermal conductivity and corrosion resistance, and can withstand the harsh environment of high temperature, high vacuum and strong electric field in semiconductor production for a long time. It also has high mechanical strength and is suitable for the use of electrostatic chucks. Microelectrodes 13 are designed in concentric circles, comb-shaped or grid-shaped according to the functional requirements of electrostatic layer, temperature sensing layer and heating layer. Concentric circle microelectrodes are suitable for the electrostatic adsorption requirements of electrostatic layer, which can realize uniform adsorption of wafers. Comb-shaped and grid-shaped microelectrodes are suitable for the temperature detection and heating requirements of temperature sensing layer and heating layer, which can realize uniform temperature detection and precise control. The layout density of microelectrodes 13 is ≥100 / cm², realizing high-density integration of functional electrodes. The selection of alumina ceramics ensures the high temperature resistance, insulation and structural stability of the ceramic plate. The diverse pattern design of microelectrode 13 adapts to the functional requirements of different layers, and the high-density layout effectively solves the problem of the difficulty of integrating functional electrodes in the existing technology, providing a structural basis for the electrostatic chuck to achieve independent and precise control of multiple temperature zones.

[0043] In this embodiment, a thin-film temperature sensor is also integrated on the surface of the microelectrode 13 of the temperature-sensing layer. The thin-film temperature sensor adopts a platinum resistance or thermocouple structure and is integrated with the microelectrode 13 by sputtering deposition. The sensor accuracy is ≤ ±0.1℃.

[0044] Specifically, the microelectrode 13 integrates a thin-film temperature sensor via magnetron sputtering. This sensor, employing a platinum resistance thermometer or thermocouple structure, is integrally formed with the microelectrode 13 during sputtering deposition. The sensor's accuracy is ≤ ±0.1℃, enabling precise, real-time temperature detection of the wafer contact area. The integrated design of the thin-film temperature sensor and the temperature-sensing layer microelectrode 13 eliminates the need for an additional sensor mounting structure, further improving the space utilization of the temperature-sensing layer. Furthermore, platinum resistance thermometers and thermocouples offer fast response times and high detection accuracy. Combined with the high-density temperature-sensing microelectrode 13, this allows for multi-point, precise detection of the electrostatic chuck surface temperature, providing accurate data support for temperature control of the heating layer and effectively improving the temperature control accuracy of the electrostatic chuck, meeting the stringent temperature requirements of semiconductor processes. Example

[0045] refer to Figure 3 Another specific step in the processing method of an electrostatic chuck with microelectrodes is as follows: S100. Determine the electrode forming surface 11 of the ceramic layer 1, and set the electrode layer 16 on the entire electrode forming surface 11 using PVD process; S200. Coat a designated area on the electrode layer 16 with photoresist 2, and bake and dry it; S300. Expose and develop the photoresist 2 coated on the electrode layer 16 to form a retention area 14 covered with photoresist 2 of a predetermined electrode pattern and an etched area 15 without photoresist coverage; S400. Etch and remove the etched area 15 of the electrode layer 16, and remove the photoresist 2 from the retention area 14 on the electrode layer 16 so that the electrode layer 16 forms a microelectrode 13 with a predetermined pattern; S500. Clean the entire ceramic layer 1 after removing the photoresist to remove residual photoresist and cleaning solution; S600. Perform surface treatment on the microelectrode 13 on the electrode forming surface 11.

[0046] Specifically, the microelectrode is directly formed by photolithography after the entire electrode layer is formed by PVD, without the need for electroplating to thicken it, making it suitable for electrostatic chuck applications with low requirements for microelectrode thickness.

[0047] In S100, the electrode forming surface 11 of the ceramic layer 1 is first activated by plasma cleaning with a cleaning power of 100-200W and a time of 3-8 minutes to remove surface impurities and improve surface activity. Then, the electrode layer 16 is integrally formed on the electrode forming surface 11 using magnetron sputtering PVD process. The electrode layer 16 is made of nickel-copper alloy with a nickel content of 80%-95% and a total thickness precisely controlled between 5-30μm. Argon gas is introduced as a protective gas during sputtering with a flow rate of 20-50sccm and a sputtering power of 200-400W to ensure that the electrode layer is deposited uniformly, free of pinholes, and firmly bonded to the ceramic layer with a bonding force ≥10N / cm. In S200, positive photoresist 2 is spin-coated onto a designated area of ​​electrode layer 16 at a spin speed of 3000-5000 r / min, resulting in a photoresist layer thickness of 10-25 μm. After coating, the photoresist is dried with hot air at 80-120℃ for 15-30 min, with stepped temperature increases to prevent bubbling and edge lifting, ensuring tight adhesion between the photoresist and the electrode layer. In S300, a photomask matching the design pattern of microelectrode 13 at a 1:1 scale is used for ultraviolet exposure at an exposure dose of 100-200 mJ / cm² and a base exposure time of 30-60 s. For every 5 μm increase in photoresist thickness, the exposure time is increased by 10 s. Development is performed using 2.38% TMAH developer at 20-25℃ for 60-120 s, forming a clearly defined retention area 14 and etched area 15, with the electrode layer in the etched area completely exposed and free of residual photoresist. In S400, a wet etching method is used for the nickel-copper alloy electrode layer. An acidic etching solution is used for etching at room temperature. The etching depth is consistent with the total thickness of the electrode layer 16. Only the etched area 15 of the electrode layer is removed without damaging the ceramic substrate. The photoresist removal adopts a combination process of "5%-10% dilute hydrochloric acid cleaning at room temperature for 10-30s → immersion in N-methylpyrrolidone swelling solution at 40-50℃ for 5-10min → ultrasonic oscillation in organic solvent at 40-60℃ for 10-30min". The organic solvent is a 1:1 mixture of N-methylpyrrolidone and acetone. The ultrasonic power is 200-300W to ensure that the photoresist is completely removed and there are no oxide residues in the electrode layer. Finally, the electrode layer forms a predetermined patterned microelectrode 13 with a linewidth of 5-50μm and a line spacing of 10-100μm. In the S500, the cleaning process involves sequentially performing O2 plasma cleaning at a power of 100-200W for 3-10 minutes, followed by anhydrous ethanol ultrasonic cleaning for 5-10 minutes, and deionized water ultrasonic cleaning for 5-10 minutes, with an ultrasonic power of 200-300W for each step. Finally, the surface is dried with nitrogen in a clean environment at 80-100℃ to remove residual adhesive, cleaning solution, and organic residues, ensuring the cleanliness of the ceramic layer and microelectrode surface.In S600, the surface treatment is consistent with that in claim 1, employing chemical passivation + chemical mechanical polishing. The passivation treatment forms a dense passivation film of 5-15nm on the surface of the microelectrode, and the surface roughness of the microelectrode after polishing is ≤0.1μm, thereby improving the corrosion resistance and conductivity of the microelectrode.

[0048] This embodiment directly prepares an electrode layer of a preset thickness using PVD technology, eliminating the need for electroplating to thicken the layer, simplifying the processing flow, shortening the production cycle, and reducing industrial mass production costs. The electrode layer is deposited using an integrated nickel-copper alloy, which has good material uniformity and a strong bond with the ceramic layer. After etching, the microelectrode is directly formed, and the pattern accuracy can be matched with that of the electroplating process. The line width and line spacing can still meet the requirements of high-density layout. The overall process retains the precision forming advantages of photolithography and development, replacing traditional machining and printing processes. It effectively solves the problems of low electrode accuracy and difficult integration, and is suitable for the production needs of electrostatic chucks for medium and low thickness microelectrodes. The process is highly operable and has a high yield rate. Example

[0049] refer to Figure 4 A method for processing an electrostatic chuck with microelectrodes further includes another specific step: S1000. Determine the electrode forming surface 11 of the ceramic layer 1, and set the electrode layer 16 on the entire electrode forming surface 11 using PVD process; S2000. Perform laser processing on a designated area on the electrode layer 16 to remove part of the electrode layer 16 according to a predetermined pattern to form a microelectrode 13; S3000. Perform surface treatment on the microelectrode 13 on the electrode forming surface 11.

[0050] Specifically, after the electrode layer is set on the entire surface using PVD technology, laser processing is used to replace the photolithography and etching process to directly form microelectrodes. This simplifies the process steps and makes it suitable for high-volume, fast-paced electrostatic chuck production scenarios.

[0051] In S1000, the electrode forming surface 11 of ceramic layer 1 is first activated by plasma cleaning with a power of 100-200W and a time of 3-8 minutes. Then, a nickel-copper alloy electrode layer 16 is deposited using magnetron sputtering PVD process with a nickel content of 80%-95% and a thickness of 5-30μm. The sputtering argon flow rate is 20-50sccm and the power is 200-400W. The bonding force between the electrode layer and the ceramic layer is ≥10N / cm, and the deposition is uniform and defect-free. In the S2000, a nanosecond laser processing device is used to pattern the electrode layer 16. The laser wavelength is 1064nm, the laser power is 5-20W, the processing speed is 500-2000mm / s, and the spot diameter is ≤20μm. According to the predetermined design pattern of the microelectrode 13, the laser path is controlled by numerical control programming to directly remove the non-electrode area of ​​the electrode layer 16, retaining the electrode part of the predetermined pattern to form the microelectrode 13. The microelectrode linewidth is controlled at 5-50μm, the line spacing is 10-100μm, and the layout density is ≥100 / cm². Nitrogen erosion is used during the laser processing to remove the metal slag generated during processing in a timely manner, avoiding slag adhesion to the electrode surface and causing short circuits. At the same time, it reduces the thermal impact of laser processing on the ceramic layer substrate and prevents microcracks from appearing in the ceramic layer. In S3000, the ceramic layer 1 after laser processing is first cleaned to remove slag: high-pressure deionized water is used for rinsing at a pressure of 0.5-1MPa, combined with ultrasonic cleaning at 200-300W for 5-10 minutes to remove surface metal slag and debris; then, surface treatment is performed according to the process of claim 1, sequentially completing chemical passivation and chemical mechanical polishing, with a passivation film thickness of 5-15nm, and the surface roughness of the microelectrode after polishing ≤0.1μm. At the same time, the edges of the laser-processed electrode are trimmed to ensure that the electrode sidewalls are flat and reduce contact resistance.

[0052] The beneficial effects of this implementation method are as follows: Laser processing replaces traditional photolithography, development, etching, and resist removal processes, significantly simplifying the microelectrode forming process, reducing process steps and the use of chemical raw materials, lowering pollution during production, further shortening the production cycle, improving production efficiency, and making it more suitable for large-scale industrial mass production; laser processing uses CNC programming control, allowing for flexible pattern adjustment and rapid adaptation to the design requirements of microelectrodes of different specifications, eliminating the need for mask fabrication and reducing mold preparation costs; the small spot diameter of laser processing still ensures high-precision forming of microelectrodes, with linewidth and spacing meeting high-density layout requirements, solving the core problems of low electrode precision and difficult integration in existing technologies; the laser processing process eliminates the use of photoresist, fundamentally avoiding the problem of residual photoresist, improving the electrical performance stability and yield of microelectrodes; simultaneously, the electrode layer is integrally deposited using PVD, bonding firmly with the ceramic layer, withstanding high temperatures ≥400℃, and suitable for the harsh operating environments of semiconductor PVD, CVD, etching, and other processes.

[0053] The present invention also provides an electrostatic chuck with microelectrodes, applied to the above embodiments one, two and three, comprising a ceramic plate, wherein the ceramic plate comprises a heating layer, a temperature sensing layer and an electrostatic layer bonded from bottom to top; the heating layer, the temperature sensing layer and the electrostatic layer are all ceramic layers with microelectrodes 13, the interlayer bonding strength is ≥15MPa, the bonding force of the microelectrodes 13 is ≥10N / cm, and the high temperature resistance is ≥400℃.

[0054] Specifically, the ceramic plate adopts a bottom-up interlayer bonding structure, consisting of a heating layer, a temperature-sensing layer, and an electrostatic layer, each layer being an alumina ceramic layer 1 with microelectrodes 13. Interlayer bonding employs a high-temperature solid-state bonding process, with the bonding temperature controlled between 800-1000℃, achieving atomic-level bonding between each ceramic layer 1. The interlayer bonding strength is ≥15MPa, ensuring the overall structural stability of the ceramic plate and preventing interlayer cracking. The bonding force between the microelectrodes 13 and the ceramic layer 1 is ≥10N / cm, capable of withstanding thermal cycling and mechanical vibration in semiconductor production, preventing microelectrodes 13 from detaching. The ceramic plate has a high temperature resistance of ≥400℃, allowing for stable long-term operation in high-temperature semiconductor processes. This ceramic plate integrates three types of microelectrodes 13—electrostatic, temperature-sensing, and heating—in a layered manner, achieving multi-functional integration. It features high interlayer bonding strength, strong microelectrode bonding, and excellent high-temperature resistance, effectively improving the structural stability and operational reliability of the electrostatic chuck, meeting the stringent requirements of semiconductor production.

[0055] In this embodiment, a ceramic plate with microelectrodes 13 is mounted on a chuck base to form an electrostatic chuck for electrostatic adsorption of sheet-like materials; the ceramic plate and the chuck base may be circular, rectangular or other irregular shapes.

[0056] Specifically, the mainstream circular structure is suitable for mainstream 300mm and 450mm wafer processing equipment, while the rectangular design can meet the needs of other large-area board substrates, such as IC carriers, flat panel displays or solar panels. The irregular structure is customized to meet the geometric constraints of specific process cavities or special wafer shapes.

[0057] The specific embodiments described herein are merely illustrative examples illustrating the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the scope defined by the spirit of the invention.

Claims

1. A method for machining an electrostatic chuck with microelectrodes, characterized in that, A ceramic chuck and chuck base are provided, comprising an electrostatic layer, a temperature-sensitive layer, and a heating layer. The ceramic chuck is mounted on the chuck base. The electrostatic layer, temperature-sensitive layer, and heating layer are all ceramic layers (1). The ceramic layer (1) is provided with microelectrodes (13). The microelectrodes (13) have a linewidth of 5-50 μm and a line spacing of 10-100 μm to achieve a high-density layout. The specific steps are as follows: S10. Determine the electrode forming surface (11) of the ceramic layer (1), and set a conductive layer (12) on the entire electrode forming surface (11). S20. Coat a designated area on the conductive layer (12) with photoresist (2) and bake to dry; S30. Expose and develop the photoresist (2) coated on the conductive layer (12) to form a retention area (14) covered with a predetermined electrode pattern photoresist (2) and an etched area (15) without photoresist coverage. S40. The etched area (15) of the conductive layer (12) is etched and removed, and the photoresist (2) of the retained area (14) on the conductive layer (12) is removed, so that the conductive layer (12) forms an electrode base layer (131) with a predetermined pattern. S50. The ceramic layer (1) after degumming is cleaned to remove residual adhesive and cleaning solution; the electrode base layer (131) on the electrode forming surface (11) is electroplated to thicken the layer (132), and the thickened layer (132) and the electrode base layer (131) form a microelectrode (13). S60. Perform surface treatment on the microelectrode (13) on the electrode forming surface (11); After the electrostatic layer, temperature-sensing layer and heating layer are independently processed into shaped microelectrodes (13) according to the above steps S10 to S60, they are subjected to interlayer bonding treatment to form a ceramic plate, and the ceramic plate is installed with the chuck base to form an electrostatic chuck.

2. The method for processing an electrostatic chuck with microelectrodes according to claim 1, characterized in that, In S10, the conductive layer (12) is set by sputtering deposition and is made of titanium-copper composite layer or chromium-copper composite layer. The total thickness of the conductive layer (12) is 150-700nm, of which the bottom layer is a titanium layer or chromium layer of 50-200nm and the surface layer is a copper layer of 100-500nm. Before setting the conductive layer (12), the electrode forming surface (11) of the ceramic layer (1) is cleaned and activated.

3. The method for processing an electrostatic chuck with microelectrodes according to claim 1, characterized in that, S20 further includes: S21. Select positive photoresist (2) and coat it on the specified area of ​​the conductive layer (12). The thickness of the photoresist (2) is 10-25 μm. S22. The conductive layer (12) after being coated with photoresist (2) is dried by hot air at a temperature of 80-120°C for 15-30 minutes.

4. The method for processing an electrostatic chuck with microelectrodes according to claim 1, characterized in that, The S30 further includes: S31. The photoresist (2) is exposed to ultraviolet light using a mask. The exposure dose is 100-200 mJ / cm², and the exposure time is 30-60 s. For every 5 μm increase in the thickness of the photoresist (2), the exposure time is increased by 10 s. The mask pattern is consistent with the design pattern of the microelectrode (13) so that the reserved area (14) is completely matched with the predetermined electrode pattern. S32. Immerse the exposed ceramic layer (1) in 2.38% TMAH developer for development treatment. The development temperature is 20-25℃ and the development time is 60-120s.

5. The method for processing an electrostatic chuck with microelectrodes according to claim 4, characterized in that, In S40, the etching depth is consistent with the total thickness of the conductive layer (12). The photoresist removal process uses 5%-10% dilute hydrochloric acid to clean the photoresist after etching at room temperature for 10-30 seconds to remove surface metal oxides and loosen the photoresist edges. The photoresist is then removed by soaking in an N-methylpyrrolidone swelling solution at 40-50℃ for 5-10 minutes, combined with ultrasonic oscillation. The soaking temperature is 40-60℃ and the processing time is 10-30 minutes. The organic solvent is one or a mixture of N-methylpyrrolidone, dimethyl sulfoxide, or acetone.

6. The method for processing an electrostatic chuck with microelectrodes according to claim 1, characterized in that, The S50 further includes: S51. The surface activation of the debonded ceramic layer (1) is performed by plasma cleaning for 3-10 minutes; S52. Use anhydrous ethanol and deionized water to ultrasonically clean in sequence, with each ultrasonic cleaning time being 5-10 minutes, in order to remove organic residues and ionic contamination; S53. Electroplating thickening treatment uses electrode base (131) as cathode, and nickel or nickel-copper alloy is selected as the electroplating metal, with an electroplating thickness of 5-30μm.

7. The method for processing an electrostatic chuck with microelectrodes according to claim 1, characterized in that, It also includes another specific step: S100. Determine the electrode forming surface (11) of the ceramic layer (1), and set the electrode layer (16) on the entire electrode forming surface (11) using PVD process. S200. Coat a designated area on the electrode layer (16) with photoresist (2) and bake to dry; S300. Expose and develop the photoresist (2) coated on the electrode layer (16) to form a retention area (14) covered with a predetermined electrode pattern photoresist (2) and an etched area (15) without photoresist coverage. S400. The etched area (15) of the electrode layer (16) is etched and removed, and the photoresist (2) of the retained area (14) on the electrode layer (16) is removed, so that the electrode layer (16) forms a microelectrode (13) with a predetermined pattern. S500. Perform a cleaning operation on the entire ceramic layer (1) after degumming to remove residual adhesive and cleaning solution; S600. Perform surface treatment on the microelectrode (13) on the electrode forming surface (11).

8. The method for machining an electrostatic chuck with microelectrodes according to claim 1, characterized in that, It also includes another specific step: S1000. Determine the electrode forming surface (11) of the ceramic layer (1), and set the electrode layer (16) on the entire electrode forming surface (11) using PVD process. S2000. Laser processing is performed on a designated area on the electrode layer (16) to remove a portion of the electrode layer (16) according to a predetermined pattern to form a microelectrode (13). S3000. Perform surface treatment on the microelectrode (13) on the electrode forming surface (11).

9. An electrostatic chuck with microelectrodes, manufactured using the processing method according to any one of claims 1-8, characterized in that, The ceramic plate includes a heating layer, a temperature sensing layer and an electrostatic layer bonded from bottom to top; the heating layer, the temperature sensing layer and the electrostatic layer are all ceramic layers with microelectrodes (13), the interlayer bonding strength is ≥15MPa, the bonding force of the microelectrodes (13) is ≥10N / cm, and the high temperature resistance is ≥400℃.

10. An electrostatic chuck with microelectrodes according to claim 9, characterized in that, A ceramic plate with microelectrodes (13) is mounted on a chuck base to form an electrostatic chuck for electrostatic adsorption of sheet materials; the ceramic plate and the chuck base may be circular, rectangular or other irregular shapes.

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