Ion-doped yttrium-based ceramic material resistant to plasma etching as well as preparation method and application of ion-doped yttrium-based ceramic material
By employing low-temperature solid-state sintering technology for ion-doped yttrium-based nanopowders, the problems of densification difficulties and poor mechanical properties of yttrium-based ceramic materials have been solved, achieving high density and excellent resistance to plasma etching, making it suitable for key components of semiconductor equipment.
Patent Information
- Application Number
- CN202511818802.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-02-10
AI Technical Summary
Existing yttrium-based ceramic materials are difficult to densify during high-temperature sintering, resulting in poor mechanical properties. This leads to particle contamination and reliability risks in the etching cavity materials, making it impossible to meet the plasma etching resistance requirements of semiconductor manufacturing.
Ion-doped yttrium-based nanopowders were used to prepare ion-doped yttrium-based ceramic materials by low-temperature solid-state sintering technology. The high density and improved mechanical strength were achieved by utilizing the lattice distortion and pinning effect caused by the doping ions.
Lowering the sintering temperature increases the density and mechanical strength of ceramic materials, enhances their wear resistance in plasma etching environments, and extends the service life of etching equipment.
Smart Images
Figure CN121494549A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of semiconductor equipment ceramic materials, and specifically relates to an ion-doped yttrium-based ceramic material resistant to plasma etching, its preparation method, and its application. Background Technology
[0002] With the rapid development of the times, the integrated circuit industry has become a crucial cornerstone for driving social development. Gordon Moore famously proposed "Moore's Law," which states that the number of transistors that can be placed per unit area of an integrated circuit roughly doubles every two years. As predicted by this law, integrated circuits have achieved improved energy efficiency through high miniaturization. The development of highly integrated semiconductor products and the industry itself is highly dependent on photolithography and etching technologies. In the front-end processes of semiconductor manufacturing, photolithography and etching are the core sequence for achieving patterning: photolithography patterns the circuit design onto a photoresist layer through optical projection, while etching uses this as a mask to precisely transfer the pattern to the underlying substrate film or single-crystal silicon through plasma etching technology. However, during the etching process, components within the process chamber are exposed to a high-density plasma environment dominated by corrosive halogen gases (CF4, Cl2, etc.), leading to corrosion and the generation of contaminants. The contaminant particles generated by corrosion not only affect wafer manufacturing but also shorten the lifespan of etching equipment. Therefore, the development and utilization of new materials with better plasma etching resistance is imperative.
[0003] The development of plasma-resistant etching materials used in integrated circuit manufacturing has roughly gone through three stages: initially, anodic aluminum oxide was phased out due to its porosity and ease of peeling; subsequently, atmospheric plasma spraying of Al2O3 improved performance but has approached its limit; currently, the focus is on Y2O3 coatings with better corrosion resistance (Liu W, et al., Materials Chemistry and Physics, 2019, 232: 471-474.). Yttrium-based materials have become one of the most promising plasma-resistant etching materials. In recent years, with the continuous improvement of performance requirements, semiconductor material technology is moving from yttrium-based coating protection to a new stage of research and application of high-performance bulk yttrium-based ceramics. Yttrium-based ceramics, with their stable chemical properties, dense bulk structure, excellent mechanical properties, and designable microstructure, have become ideal materials to meet the stringent requirements of advanced semiconductor manufacturing. However, because Y2O3 ceramics are prone to generating reaction products such as YOF in fluorine-based plasma etching environments, there is a risk of particulate contamination, shortening the service life of the etching chamber. YOF ceramics readily undergo fluorination under high-energy fluorine-containing plasma to form Y5O4F7. The accompanying volume shrinkage creates internal stress between the reaction layer and the substrate, inducing cracks and causing particle escape. Furthermore, currently reported yttrium-based ceramics suffer from high sintering temperatures, difficulty in densification, and poor mechanical properties, leading to particle contamination and reliability risks when used as etching cavity materials. Therefore, there is an urgent need to develop a yttrium-based ceramic material that combines high density with excellent plasma etching resistance to meet the pressing requirements for cavity materials in advanced semiconductor core components. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide an ion-doped yttrium-based ceramic material resistant to plasma etching, its preparation method and application, so as to overcome the defects of existing yttrium-based ceramics, such as high sintering temperature, difficulty in densification, and poor mechanical properties, which lead to particle contamination and reliability risks when used as etching cavity materials.
[0005] This invention provides an ion-doped yttrium-based ceramic material resistant to plasma etching, wherein the ion-doped yttrium-based ceramic material is prepared by low-temperature solid-state sintering technology using ion-doped yttrium-based nanoparticles as raw materials.
[0006] Preferably, the yttrium-based nanopowder in the ion-doped yttrium-based nanopowder comprises a single-phase material containing yttrium atoms or a composite material with yttrium as the main phase; wherein the single-phase material containing yttrium atoms includes Y₂O₃ and Y₃Al₅O₃. 12 YAG, YOF, YF3, and Y7O6F9 are all mentioned; the composite material with yttrium as the main phase includes YF3-Y7O6F9, Y7O6F9-YOF, Y2O3-Al2O3, and Y3Al5O3. 12 One of the Al2O3.
[0007] Preferably, the doping ions in the ion-doped yttrium-based nanopowder include, but are not limited to, Ce. 3+ 、Nd 3+ ,Sc 3+ Eu 3 + Re 3+ Pm 3+ Lu 3+ Tm 3+ Dy 3+ Ho 3+ Gd 3+ Yb 3+ 、Sm 3+ 、Tb 3+ Pr 3+ Er 3+ At least one of transition metal ions or rare earth ions.
[0008] This invention provides a method for preparing ion-doped yttrium-based ceramic materials resistant to plasma etching, comprising: using ion-doped yttrium-based nanoparticles as raw materials and employing low-temperature solid-state sintering technology to prepare ion-doped yttrium-based ceramic materials.
[0009] Preferably, the preparation method of the ion-doped yttrium-based nanopowder includes, but is not limited to, any one of the following: coprecipitation method, hydrothermal method, sol-gel method, and solid-phase reaction method.
[0010] More preferably, the ion-doped yttrium-based nanopowder is prepared by a hydrothermal method, specifically including the following steps: weighing yttrium source, fluorine source and dopant ions according to stoichiometric ratio, dissolving them separately in deionized water, then mixing them evenly, adjusting the pH of the mixed solution, stirring thoroughly and transferring it to a reaction vessel for hydrothermal reaction; after the reaction is completed, centrifuging, washing, drying and calcining are performed to obtain ion-doped yttrium-based nanopowder.
[0011] Preferably, the low-temperature solid-state sintering technology includes, but is not limited to, any one of discharge plasma sintering, hot pressing sintering, cold sintering, and microwave sintering.
[0012] Preferably, the sintering temperature is 600-1200 ℃, the sintering pressure is 60-80 MPa, the heating rate is 20-100 ℃ / min, and the holding time is 1-5 min.
[0013] More preferably, the sintering temperature is 600 ℃, 650 ℃, 800 ℃, 900 ℃, 1000 ℃, 1100 ℃ or 1200 ℃.
[0014] Preferably, the ion-doped yttrium-based ceramic material needs to be polished on both sides to achieve a surface roughness of less than 20 nm (i.e., Ra≤0.02) before it can be put into use.
[0015] The present invention also provides an application of the above-mentioned plasma-resistant ion-doped yttrium-based ceramic material in the etching process chamber of semiconductor equipment.
[0016] Preferably, the applications include, but are not limited to, chamber liners, electrostatic chucks, spray heads, focusing rings, and edge rings.
[0017] This invention addresses the urgent need for longer service life and superior stability of core components in current advanced semiconductor manufacturing processes by proposing a novel plasma-etch-resistant ion-doped yttrium-based ceramic material. Through an ion-doping strategy, the doping concentration and spatial distribution are precisely controlled, synergistically combining the "pinning effect" and solid solution strengthening to construct an ultrafine-grained, ultra-dense microstructure. This further enhances the plasma-etch resistance of yttrium-based ceramic materials, promotes the localization of key ceramic materials for semiconductor equipment, and is of great significance for improving the security of my country's semiconductor industry chain.
[0018] Beneficial effects
[0019] (1) This invention effectively controls the sintering activity of yttrium-based ceramics by introducing dopant ions with specific radii and valence states, and successfully reduces the sintering temperature required to achieve high densification from over 1300 °C in traditional processes to approximately 1000 °C. The mechanism of this effect is that the lattice distortion induced by the dopant ions increases the lattice energy and atomic diffusion barrier of the system, thereby driving the densification process at a lower temperature.
[0020] (2) By introducing doping ions into yttrium-based ceramic materials, strong segregation is generated at the grain boundaries, causing solute resistance and producing a "pinning effect", which delays grain growth and promotes densification. The Vickers hardness value of the ion-doped yttrium-based ceramics obtained by this invention can reach an average of 11 GPa. This characteristic shows that the ion-doped yttrium-based ceramic materials have high density and excellent mechanical strength, which can meet the stringent requirements of key components of semiconductor equipment for wear resistance and impact resistance, and have broad application prospects.
[0021] (3) The ion-doped yttrium-based ceramics obtained by the present invention have a transmittance of up to 85% in the mid-infrared band and have great application potential in core components such as semiconductor observation windows. Attached Figure Description
[0022] Figure 1 The image shows the XRD pattern of the YF3:Ce nanopowder prepared in Example 1.
[0023] Figure 2The visible-infrared transmittance diagram is shown for the YF3:Ce ceramic material prepared in Example 1.
[0024] Figure 3 The images show SEM comparisons of the YF3:Ce ceramic material prepared in Example 1 before and after etching.
[0025] Figure 4 The image shows the AFM image of the YF3:Ce ceramic material prepared in Example 1 after etching.
[0026] Figure 5 The XRD patterns are of the YOF / Y7O6F9:Tm nanopowder and ceramic prepared in Example 2.
[0027] Figure 6 The image shows a SEM image of the YOF / Y7O6F9:Tm ceramic material prepared in Example 2.
[0028] Figure 7 Vickers hardness diagram of the YOF / Y7O6F9:Tm ceramic material prepared in Example 2. Detailed Implementation
[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.
[0030] Example 1
[0031] This embodiment provides a YF3:Ce ceramic material, the preparation method of which includes the following steps:
[0032] (1) Preparation of YF3:Ce nanopowder by hydrothermal method
[0033] Yttrium nitrate hexahydrate (Y(NO3)3·6H2O), sodium fluoroborate (NaBF4), and cerium nitrate hexahydrate (Ce(NO3)3·6H2O) powders were weighed according to stoichiometric ratios and dissolved in deionized water. The solutions were stirred continuously at 600 rpm on a magnetic stirrer until completely dissolved. After the two solutions were mixed thoroughly, the pH of the mixed solution was adjusted to 3.0 using ammonia (NH3·H2O) or nitric acid (HNO3) solution, and the mixture was stirred thoroughly for 30 min. The mixed solution was then transferred to a 500 mL polytetrafluoroethylene-lined container and placed in a high-pressure reactor for hydrothermal reaction at 180 °C for 6 h. After the reaction was completed, the reactor was removed and allowed to cool naturally to room temperature in air. The supernatant was removed, the white precipitate was collected, and washed by centrifugation with deionized water and anhydrous ethanol. Then, it was placed in a forced-air drying oven and dried at 70 °C for 24 h to obtain a series of YF3:Ce nanoparticles containing 2 mol%, 4 mol%, 6 mol%, and 8 mol% cerium nitrate hexahydrate, respectively.
[0034] (2) Preparation of YF3:Ce ceramic materials
[0035] YF3:Ce powder was loaded into a graphite mold with an inner diameter of 10 mm and sintered by spark plasma, using either direct sintering or a two-step sintering method. The sintering conditions were 650 ℃, holding time of 2 min, heating rate of 70 ℃ / min, and pressure of 70 MPa to obtain ceramic samples. The obtained samples were then surface-polished to obtain YF3:Ce ceramic sheets with a thickness of 1 mm.
[0036] The obtained YF3:Ce nanoparticles were characterized by XRD, such as... Figure 1 As shown, all diffraction peaks are consistent with the standard card (PDF#70-1935) for YF3, and no impurity diffraction peaks were observed, indicating high sample purity. Due to Ce... 3+ The radius (1.143 Å) is greater than Y. 3+ (0.9 Å), the XRD diffraction peaks shift slightly towards smaller angles. And with Ce... 3+ With increasing doping concentration, the average particle size of the powder gradually increases, and the overall uniformity improves. The density of YF3:Ce ceramic sheets prepared by SPS sintering is 5.06 g / cm³. 3 It has a density of 100%, which is comparable to the theoretical density of YF3.
[0037] Figure 2 The visible-infrared transmittance diagram of YF3:Ce ceramic material shows that the transmittance of YF3:Ce (8mol%) ceramic material is about 20% in the visible light region and 85% in the infrared region, which can be used for infrared observation windows in semiconductor equipment.
[0038] YF3:Ce (8 mol%) ceramic wafers were subjected to ICP etching using a mixture of CF4 and Ar gases for 1 hour. The SEM morphology of the ceramic surface before and after etching was observed. Figure 3 ) and AFM on etched ceramic surface ( Figure 4 It was found that no obvious holes or pits were observed on the surface after etching, indicating that the ceramic has excellent resistance to plasma etching in a fluorine-based plasma environment.
[0039] Example 2
[0040] The preparation method of YOF / Y7O6F9:Tm ceramic material in this embodiment includes the following steps:
[0041] (1) Preparation of YOF / Y7O6F9:Tm nanopowder by hydrothermal method
[0042] Yttrium nitrate hexahydrate and ammonium fluoride (NH4F) powder were weighed separately according to stoichiometric ratios. Then, 5 mol% of holmium nitrate hexahydrate (Tm(NO3)3·6H2O) powder was weighed and dissolved in deionized water. The solution was stirred continuously at 500 rpm on a magnetic stirrer until completely dissolved. After mixing the resulting solution thoroughly, the pH of the mixture was adjusted to 9.0 using ammonia water, and stirring was continued for 30 min. The mixture was then transferred to a 500 mL polytetrafluoroethylene-lined container and placed in a high-pressure reactor for hydrothermal reaction at 180 ℃ for 12 h. After the reaction, the reactor was allowed to cool naturally to room temperature in air. The supernatant was removed, and the white precipitate was collected. It was washed by centrifugation with deionized water and anhydrous ethanol, respectively, and then placed in a forced-air drying oven and dried at 70 °C for 12 h. The dried precursor powder was then placed in a muffle furnace for high-temperature calcination. The calcination program was set to raise the temperature to 850 °C at a heating rate of 5 °C / min and hold at this temperature for 3 h to finally obtain YOF / Y7O6F9:Tm nanoparticles.
[0043] (2) Preparation of YOF / Y7O6F9:Tm ceramic materials
[0044] YOF / Y7O6F9:Tm nanoparticles were sintered using the SPS method at a sintering temperature of 1000 ℃, a holding time of 2 min, a heating rate of 100 ℃ / min, and a pressure of 70 MPa to obtain YOF / Y7O6F9:Tm ceramic materials with an average density of 5.28 g / cm³. 3 The relative density can reach 100%.
[0045] XRD characterization of YOF / Y7O6F9:Tm powder and ceramic materials, such as Figure 5As shown in the figure, the diffraction peaks of the sample powder and ceramic are consistent with those of the YOF standard card (PDF#71-2100) and the Y7O6F9 standard card (PDF#70-0867), and no other impurity peaks are observed, indicating that the sample has high purity.
[0046] From the SEM image of YOF / Y7O6F9:Tm ceramic ( Figure 6 As can be seen, the ceramic surface has a good finish after polishing, which can initially meet the requirements for use in semiconductor equipment ceramics. Vickers hardness testing shows that Tm... 3+ The maximum Vickers hardness of the doped ceramic bulk can reach 10.42 GPa. Figure 7 The hardness of yttrium-based ceramics is significantly improved compared to that of undoped yttrium-based ceramics (7.7 Gpa).
[0047] Comparative Example 1
[0048] The preparation method of YOF / Y7O6F9:Tm ceramic material in this embodiment is the same as in Example 2, except that: in step (2), YOF / Y7O6F9:Tm nanoparticles are sintered using the SPS sintering method at a sintering temperature of 1250 ℃, a holding time of 2 min, a heating rate of 100 ℃ / min, and a pressure of 70 MPa to obtain ceramic YOF / Y7O6F9:Tm samples. The average density of these samples is 5.19 g / cm³ compared to the ceramic samples prepared in Example 2. 3 The relative density is 99.24%.
Claims
1. A plasma-etch-resistant ion-doped yttrium-based ceramic material, characterized in that, The ion-doped yttrium-based ceramic material is prepared by using ion-doped yttrium-based nanoparticles as raw materials and employing low-temperature solid-state sintering technology.
2. The plasma-etch-resistant ion-doped yttrium-based ceramic material according to claim 1, characterized in that, The ion-doped yttrium-based nanopowder includes a single-phase material containing yttrium atoms or a composite material with yttrium as the main phase; wherein the single-phase material containing yttrium atoms includes Y₂O₃ and Y₃Al₅O₃. 12 YOF, YF3, and Y7O6F9 are all selected from the following composite materials: YF3-Y7O6F9, Y7O6F9-YOF, Y2O3-Al2O3, and Y3Al5O3. 12 One of the Al2O3.
3. The plasma-etch-resistant ion-doped yttrium-based ceramic material according to claim 1, characterized in that, The doping ions in the ion-doped yttrium-based nanopowder include Ce. 3+ 、Nd 3+ ,Sc 3+ Eu 3+ Re 3+ Pm 3+ Lu 3+ Tm 3+ Dy 3+ Ho 3+ Gd 3+ Yb 3+ 、Sm 3+ 、Tb 3+ Pr 3+ Er 3+ At least one of them.
4. A method for preparing an ion-doped yttrium-based ceramic material resistant to plasma etching, characterized in that, The preparation method includes: using ion-doped yttrium-based nanopowder as raw material, and preparing ion-doped yttrium-based ceramic materials by low-temperature solid-state sintering technology.
5. The preparation method according to claim 4, characterized in that, The preparation method of the ion-doped yttrium-based nanopowder includes any one of the following: coprecipitation method, hydrothermal method, sol-gel method, and solid-phase reaction method.
6. The preparation method according to claim 4, characterized in that, The low-temperature solid-state sintering technology includes any one of the following: discharge plasma sintering, hot pressing sintering, cold sintering, and microwave sintering.
7. The preparation method according to claim 6, characterized in that, The sintering temperature is 600-1200 ℃, the sintering pressure is 60-80 MPa, the heating rate is 20-100 ℃ / min, and the holding time is 1-5 min.
8. The preparation method according to claim 4, characterized in that, The ion-doped yttrium-based ceramic material needs to be polished on both sides to achieve a surface roughness of less than 20 nm before it can be put into use.
9. The application of the plasma-resistant ion-doped yttrium-based ceramic material as described in claim 1 in the etching process chamber of a semiconductor device.