Plasma etch resistant silicon nitride ceramic composition, cast slurry, cast sheet, green sheet, green block, ceramic and method of manufacture, electrostatic chuck, semiconductor equipment component

Abstract

The application discloses a plasma-erosion-resistant silicon nitride ceramic composition, a casting slurry, a casting sheet, a green sheet, a green block, a ceramic and a preparation method, an electrostatic chuck and a semiconductor equipment component, and belongs to the technical field of semiconductor ceramic materials. The plasma-erosion-resistant silicon nitride ceramic composition comprises, in terms of molar parts, 85-95 parts of silicon nitride and 5-15 parts of a sintering aid, wherein the sintering aid comprises a metal fluoride sintering aid. The application introduces a fluorine-containing and / or nitrogen-containing compound sintering aid to form a stable grain boundary phase in a fluorine-containing plasma environment, realizes synergistic protection, adapts to different plasma environments, improves the corrosion resistance of Si3N4 ceramic, solves the defect of poor plasma-erosion resistance, optimizes the proportion of the aid to ensure sufficient liquid-phase sintering, and avoids excessively thick grain boundaries; the coefficient of thermal expansion is stably 2.6-3.1*10 ‑6 / ℃, which is highly matched with a silicon wafer.

Description

Technical Field

[0001] This invention relates to the field of semiconductor ceramic materials technology, specifically to a plasma-resistant silicon nitride ceramic composition, casting slurry, casting sheet, green sheet, green block, ceramic and its preparation method, electrostatic chuck, and semiconductor equipment components. Background Technology

[0002] In semiconductor equipment, the materials used in components are a key factor affecting equipment performance. Especially in etching machines and PECVD equipment used in wafer manufacturing, high-energy fluorine-containing plasmas can corrode the cavity and internal components through physical action and chemical reactions. This not only shortens the lifespan of components and reduces the performance of the equipment, but also generates non-volatile fluoride impurities, affecting the cleanliness of the cavity.

[0003] Currently, commonly used plasma-resistant materials include quartz (SiO2), high-purity alumina (Al2O3), aluminum nitride (AlN), yttrium oxide (Y2O3), and yttrium aluminum garnet (YAG). Quartz exhibits poor resistance to plasma corrosion and a short lifespan. For high-purity Al2O3, AlN, Y2O3, and YAG, high-energy fluorine-containing plasma produces solid particles such as YF3 and AlF3. These contaminating particles can cause fatal defects in wafer manufacturing. Furthermore, as wafer size increases, the size of the plasma etching process cavity also needs to increase accordingly. To achieve efficient and uniform etching within a larger cavity, higher-power plasma is often required, thus intensifying the physical bombardment and chemical erosion of the cavity's inner wall materials. For high-purity Al2O3 and AlN, the problems of particle contamination and short lifespan are clearly amplified when facing high-power plasma erosion.

[0004] Silicon nitride (Si3N4), as a covalent compound, produces SiF4 gas under high-energy fluorine-containing plasma, without generating solid particles, thus improving the cleanliness of the chamber. Simultaneously, Si3N4 ceramic material also possesses advantages such as high melting point, high hardness, wear resistance, high flexural strength, and a thermal expansion coefficient similar to Si. These advantages make Si3N4 ceramic one of the high-performance candidate materials for semiconductors. However, due to its relatively poor plasma corrosion resistance compared to Y2O3, it has not been widely used in semiconductor device cavities and internal components. Therefore, developing a high-performance Si3N4 ceramic material with high plasma corrosion resistance has become a crucial issue that urgently needs to be addressed. Summary of the Invention

[0005] Therefore, the present invention provides a silicon nitride ceramic composition resistant to plasma corrosion, silicon nitride ceramic and preparation method, electrostatic chuck, and semiconductor device component to solve the defect of poor plasma corrosion resistance of Si3N4 ceramic materials in the prior art.

[0006] In a first aspect, the present invention provides a silicon nitride ceramic composition resistant to plasma corrosion, wherein the raw materials, by molar amount, include: 85-95 parts of silicon nitride and 5-15 parts of sintering aid, wherein the sintering aid includes a metal fluoride sintering aid.

[0007] In one optional embodiment, the metal fluoride sintering aid is a Group IIIB or IIA metal fluoride sintering aid;

[0008] Meet at least one of the following:

[0009] The sintering aids also include metal nitrides;

[0010] The sintering aid is a combination of metal nitrides and / or group IIIB, IIA metal fluorides;

[0011] The metal nitride is AlN;

[0012] The sintering aids are selected from YF3, CaF2, MgF2, CeF4 and AlN;

[0013] The sintering aid is a combination of AlN with YF3, CaF2 and / or CeF4;

[0014] The sintering aids are YF3, CaF2, CeF4, and AlN, with a molar ratio of 0-5:0-5:0-5:2-5.

[0015] The raw materials in molar proportions are: 85 parts Si3N4, 5 parts YF3, 5 parts MgF2, and 5 parts AlN; or

[0016] 85 parts Si3N4, 2 parts YF3, 3 parts CaF2, 3 parts MgF2, 3 parts CeF4, 4 parts AlN; or

[0017] 90 parts Si3N4, 2 parts YF3, 2 parts CaF2, 2 parts MgF2, 2 parts CeF4, 2 parts AlN; or

[0018] 90 parts Si3N4, 4 parts YF3, 2 parts CaF2, 2 parts CeF4, 2 parts AlN; or

[0019] 90 parts Si3N4, 5 parts CaF2, 1 part MgF2, 2 parts CeF4, 2 parts AlN; or

[0020] 95 parts Si3N4, 3 parts YF3, 1 part MgF2, and 1 part CeF4.

[0021] Secondly, the present invention provides a silicon nitride casting slurry comprising the aforementioned plasma-resistant silicon nitride ceramic composition.

[0022] Meet at least one of the following:

[0023] The viscosity of the casting slurry is 180–240 mPa·s;

[0024] It also includes 30-50 moles of organic solvent, 1-5 moles of binder, 0.5-2 moles of plasticizer and 0.5-3 moles of dispersant;

[0025] The adhesive is a polyvinyl alcohol C1-C4 alkyl aldehyde; and / or

[0026] The plasticizer is a di-4 alkyl phthalate and / or polyethylene glycol; and / or

[0027] The organic solvent is a C1-C4 alkyl alcohol, a C3-C4 ketone, and / or isopropanol; and / or

[0028] The dispersant is a tri(C1-C4) alkyl phosphate and / or fish oil.

[0029] The dispersant is triethyl phosphate and / or fish oil; and / or

[0030] The adhesive is polyvinyl butyral; and / or

[0031] The plasticizer is dibutyl phthalate and / or polyethylene glycol; and / or

[0032] The organic solvent is ethanol, butanone, and / or isopropanol; and / or

[0033] The molar composition of the organic solvent, the binder, the plasticizer, and the dispersant is as follows:

[0034] A mixed solvent of 30 parts each of butanone and anhydrous ethanol in a molar ratio of 2:1; 3 parts polyvinyl butyral; 1.5 parts dibutyl phthalate; and 3 parts triethyl phosphate in a molar ratio; or

[0035] A mixture of 50 parts isopropanol and anhydrous ethanol in a 1:1 molar ratio, 1 part polyvinyl butyral, 0.5 parts polyethylene glycol, and 1.5 parts fish oil; or

[0036] The mixture consists of 38 parts of a mixed solvent composed of methyl ethyl ketone, isopropanol, and anhydrous ethanol in a molar ratio of 1:2:3; 5 parts of polyvinyl butyral; 2 parts of a plasticizer mixture composed of dibutyl phthalate and polyethylene glycol in a molar ratio of 1:1; and 3 parts of a dispersant mixture composed of triethyl phosphate and fish oil in a molar ratio of 2:3.

[0037] Thirdly, the present invention provides a silicon nitride cast sheet comprising the above-mentioned plasma-resistant silicon nitride ceramic composition or the silicon nitride casting slurry described above, wherein the thickness of the cast sheet is 0.3 to 0.6 mm.

[0038] Fourthly, the present invention provides a silicon nitride green sheet comprising the above-mentioned plasma-resistant silicon nitride ceramic composition, or the above-mentioned silicon nitride casting slurry, or the above-mentioned silicon nitride casting sheet.

[0039] Fifthly, the present invention provides a silicon nitride green block comprising the above-mentioned plasma-resistant silicon nitride ceramic composition, or the above-mentioned silicon nitride casting slurry, or the above-mentioned silicon nitride casting sheet, or the above-mentioned silicon nitride green sheet.

[0040] In a sixth aspect, the present invention provides a plasma-resistant silicon nitride ceramic comprising the above-described plasma-resistant silicon nitride ceramic composition, or the above-described silicon nitride casting slurry, or the above-described silicon nitride casting sheet, or the above-described silicon nitride green sheet, or the above-described silicon nitride green block.

[0041] In a seventh aspect, the present invention provides a method for preparing the above-mentioned plasma-resistant silicon nitride ceramic, comprising the following steps:

[0042] (1) Silicon nitride is mixed with sintering aids to obtain a primary mixture;

[0043] (2) The binder, plasticizer and organic solvent are mixed to obtain a solvent mixture. The primary mixture is then mixed with the solvent mixture and dispersant and ball-milled to obtain a silicon nitride green sheet casting slurry.

[0044] (3) After degassing the casting slurry, casting, and cutting, silicon nitride casting sheets are obtained;

[0045] (4) Drill holes in the silicon nitride cast wafer, stack them to obtain silicon nitride green wafers, and then perform warm isostatic pressing to obtain silicon nitride green blocks;

[0046] (5) The silicon nitride green block is debinded and sintered to obtain silicon nitride ceramic resistant to plasma corrosion;

[0047] The thickness of the silicon nitride cast sheet is 0.3–0.6 mm; and / or

[0048] The diameter of the holes in the silicon nitride cast wafer is 1–3 mm; and / or

[0049] The isostatic pressing is performed at a temperature of 60–80°C, a pressure of 30–60 MPa, and a time of 60–90 min; and / or

[0050] The glue removal temperature is 450–650℃, and the glue removal holding time is 6–8h; the sintering temperature is 1700–1850℃, and the sintering temperature holding time is 2–4h.

[0051] Eighthly, the present invention provides an electrostatic chuck made of raw materials comprising the above-mentioned plasma-resistant silicon nitride ceramic composition, or the above-mentioned silicon nitride casting slurry, or the above-mentioned silicon nitride casting sheet, or the above-mentioned silicon nitride green sheet, or the above-mentioned silicon nitride green block, or the above-mentioned plasma-resistant silicon nitride ceramic.

[0052] In a ninth aspect, the present invention provides a semiconductor device component, the raw material comprising the above-mentioned plasma-resistant silicon nitride ceramic composition, or made from the above-mentioned silicon nitride casting slurry, or the above-mentioned silicon nitride casting wafer, or the above-mentioned silicon nitride green wafer, or the above-mentioned silicon nitride green block, or the above-mentioned plasma-resistant silicon nitride ceramic.

[0053] The semiconductor equipment components are plasma etching equipment, gas dispersion disks, nozzles, or chamber covers.

[0054] The technical solution of this invention has the following advantages:

[0055] 1. The plasma-resistant silicon nitride ceramic composition provided by this invention, through the introduction of fluorine-containing and / or nitrogen-containing compound sintering aids, forms a stable grain boundary phase in a fluorine-containing plasma environment, achieving synergistic protection and adapting to different plasma environments (such as CF4 / O2, NF3). This improves the corrosion resistance of Si3N4 ceramics prepared from it, solving the defect of poor plasma corrosion resistance in the prior art. The optimized proportion of aids (5-15 parts) ensures sufficient liquid-phase sintering. The relative density of each embodiment is ≥98.1%, while avoiding excessively thick grain boundaries. The coefficient of thermal expansion of each embodiment is stable at 2.6-3.1×10⁻⁶. -6 / ℃, highly matched to silicon wafers, reducing thermal stress by 70%.

[0056] 2. The additive system of the plasma-resistant silicon nitride ceramic composition provided by this invention works synergistically. The combination of metal fluoride and metal nitride enables the ceramic obtained therefrom to form a stable grain boundary phase in a fluorine-containing plasma environment, achieving "synergistic protection". The fluoride element (F) is pre-embedded in the grain boundary, reducing structural damage during plasma erosion, while the nitride enhances the grain boundary toughness. The optimal combination of additives not only improves corrosion resistance but also enhances fracture toughness and hardness. Group IIIB / IIA fluorides have similar ionic radii and high lattice matching with Si3N4, reducing grain boundary segregation. The fluoride-nitride system has broad adaptability to different plasmas such as CF4 / O2 and NF3. Molar ratio regulation prevents the formation of eutectic phases, improves grain boundary uniformity (SEM shows no segregation), has clear ratio boundaries, and a batch fluctuation rate of <5%. The synergistic effect of metal fluoride and metal nitride results in a balance between hardness and toughness.

[0057] 3. The silicon nitride casting slurry provided by the present invention has a viscosity of 180-240 mPa·s, possesses suitable rheological properties and excellent stability (>48 hours) and good dispersibility. Ceramic powder with this viscosity can be uniformly distributed in the slurry, thereby obtaining a high relative density (≥99%) and uniform microstructure after sintering, and thus obtaining ceramics with better plasma corrosion resistance and mechanical properties.

[0058] The addition range and types of organic solvents, binders, plasticizers, and dispersants are also limited. Binders provide skeletal strength, plasticizers increase flexibility, dispersants prevent powder agglomeration, and organic solvents adjust viscosity. This combination gives the slurry a suitable viscosity of 200±50 mPa·s, making it suitable for casting and suitable for preparing complex-shaped parts such as thin sheets. The slurry stability exceeds 48 hours, ensuring the continuity and consistency of the production process. The synergistic effect of binders and plasticizers gives the cast green sheets sufficient strength and flexibility, making them less prone to cracking or deformation during subsequent cutting, punching, lamination, and warm isostatic pressing. The effective action of the dispersant promotes uniform powder distribution in the slurry. Solvents (such as ethanol, methyl ethyl ketone, and isopropanol) are less toxic than traditionally used solvents such as toluene, reducing volatile organic compound (VOC) emissions by approximately 60%, which better meets the environmental protection requirements of modern industry and improves the working environment.

[0059] Each scheme targets different needs: Scheme 1: A 30-part mixed solvent consisting of methyl ethyl ketone (MEK) and anhydrous ethanol in a 2:1 molar ratio; 3 moles of polyvinyl butyral; 1.5 moles of dibutyl phthalate; and 3 moles of triethyl phosphate, emphasizing viscosity stability and environmental friendliness; Scheme 2: A 50-part mixed solvent consisting of isopropanol and anhydrous ethanol in a 1:1 molar ratio; 1 mole of polyvinyl butyral; 0.5 moles of polyethylene glycol; and 1.5 moles of fish oil, focusing on uniformity and thermal stability; Scheme 3: A 1:2:3 mixture of MEK, isopropanol, and anhydrous ethanol. The casting slurry consisted of a 38-molar mixture of alcohol, 5 molars of polyvinyl butyral, 2 molars of a plasticizer mixture of dibutyl phthalate and polyethylene glycol (molar ratio 1:1), and 3 molars of a dispersant mixture of triethyl phosphate and fish oil (molar ratio 2:3). Through comprehensive optimization, the ceramics prepared from the casting slurry in all embodiments exhibited a relative density ≥99%. This high density directly translates into excellent mechanical and thermal properties, as shown in Table 3. The ceramics prepared from the casting slurry in all embodiments had a Vickers hardness ≥14.3 GPa and a fracture toughness ≥5.8 MPa·m¹. / ², coefficient of thermal expansion (2.6-3.1×10 -6 ( / ℃) is a perfect match for silicon wafers.

[0060] 4. The silicon nitride cast sheet provided by the present invention has a thickness of 0.3 to 0.6 mm, which limits the thickness range of the cast sheet and ensures that the green sheet can be uniformly stressed and densified uniformly during subsequent lamination and isostatic pressing processes.

[0061] 5. The silicon nitride green sheet provided by the present invention is prepared by punching, cutting and stacking the cast film to produce a green sheet with complex internal flow channels, cavities and other structures.

[0062] 6. The silicon nitride green block provided by the present invention has high density uniformity and low crack rate.

[0063] 7. The plasma-resistant silicon nitride ceramic provided by the present invention has strong resistance to plasma corrosion, while also possessing high mechanical properties, high density, and high reliability.

[0064] 8. The synergistic effect of the various processes in the silicon nitride ceramic preparation method provided by this invention not only improves the corrosion resistance, mechanical properties, and reliability of the product, but also reduces energy consumption and environmental risks. This supports the long lifespan and high yield of semiconductor equipment components (such as electrostatic chucks and gas dispersion disks). The preparation method provided by this invention has high process compatibility, supporting thin-film preparation and reducing energy consumption by 40%. The formulation and casting process perfectly match the preparation of 0.3-0.6mm thick thin films, warm isostatic pressing (60-80℃, 30-60MPa), and atmosphere sintering (sintering cycle ≤12 hours) processes. This ensures homogeneous products with uniform density (gradient <0.5%), complex shapes, and high performance for large-sized components, reducing energy consumption by 40% and achieving a yield rate of ≥95% (compared to ≤85% with traditional processes). The segmented heating process from debinding to sintering avoids cracking, and the β-Si3N4 grain interlocking structure remains intact. Simultaneously, the synergistic optimization of process parameters, such as warm isostatic pressing (60-80℃, 30-60MPa) and sintering (1700-1850℃), ensures uniform density (gradient <0.5%), with performance degradation of <5% after 100 thermal cycles (-55-150℃), and a 30% improvement in yield.

[0065] 9. The electrostatic chuck provided by this invention has a coefficient of thermal expansion of 2.7 to 3.1 × 10⁻⁶. -6 / ℃, matching silicon wafers, clamping force fluctuation <3%, warpage ≤0.1mm when heated to 300℃; aperture uniformity (±0.05mm) ensures stable plasma distribution, etching uniformity ≥95%; chamber cover / nozzle: high hardness (≥14.3GPa) resists impact, thermal shock resistance (ΔT=500℃) without cracks, maintenance cycle extended to 2 years; suitable for various semiconductor equipment such as etching, CVD, PVD, etc., improving the overall equipment yield.

[0066] 10. The semiconductor equipment components provided by this invention have a lifespan of ≥1000 hours in CF4 / O2 plasma (compared to ≤200 hours for oxide ceramics), SiF4 gaseous corrosion products avoid particulate contamination, and the wafer defect rate is reduced to ≤0.01 particles / cm²; applicable to various semiconductor equipment scenarios such as etching, CVD, and PVD. Attached Figure Description

[0067] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0068] Figure 1 This is a flow chart of the silicon nitride ceramic preparation process of the present invention;

[0069] Figure 2 This is a scanning electron microscope (SEM) image magnified 6k times for Example 4;

[0070] Figure 3 This is the XRD pattern of Example 4. Detailed Implementation

[0071] The following embodiments are provided to better understand the present invention, but the following embodiments do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the scope of protection of the present invention.

[0072] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0073] Examples 1-2: Preparation of silicon nitride ceramics resistant to plasma corrosion

[0074] Formula: The molar percentage composition of the raw materials is shown in Table 1 and Table 2.

[0075] Preparation process: The process flow diagram is as follows Figure 1 As shown,

[0076] Mixing: Weigh the Si3N4 powder and sintering aid according to the formula in Table 1, place them in a ball mill jar, and ball mill them for 12 hours with anhydrous ethanol as the medium. After drying, sieve to obtain a uniform powder mixture.

[0077] Preparation of slurry (according to the dosage in Table 2): Mix the organic solvent, binder and plasticizer evenly, then add the dispersant and the above powder mixture and mix well. Ball mill for 24 hours to obtain a uniform and stable silicon nitride casting slurry with a viscosity of 240 mPa·s. After 48 hours, the viscosity is 218 mPa·s, and the slurry performance is stable.

[0078] Casting and lamination: The casting slurry is degassed under vacuum in a casting machine, then cast and cut to obtain a silicon nitride cast sheet with a thickness of 0.5 mm. The perforated cast sheet has a diameter of 2 mm, resulting in a perforated silicon nitride cast sheet. The perforated silicon nitride cast sheets are then stacked to obtain a silicon nitride green sheet.

[0079] Warm isostatic pressing: The laminated silicon nitride green sheets were placed in a plastic bag and vacuum sealed, and then subjected to warm isostatic pressing (temperature: 70℃, pressure: 50MPa, time: 75min) to obtain silicon nitride green blocks. The test results showed that the density uniformity of the green blocks was ≥99% and the crack rate was <0.1%.

[0080] Debinding and sintering: The pressed silicon nitride green sheet is debinded and sintered under a nitrogen atmosphere. Debinding stage: The temperature is increased to 600℃ at 1℃ / min and held for 7 hours; Sintering stage: The temperature is increased to 1800℃ at 5℃ / min and held at 1800℃ for 2 hours, and then cooled in the furnace to obtain dense silicon nitride ceramic resistant to plasma corrosion.

[0081] Examples 3-4: Preparation of silicon nitride ceramics resistant to plasma corrosion

[0082] Formulation: The molar percentage composition of raw materials is shown in Table 1; the molar composition of additives is shown in Table 2.

[0083] Preparation process: The process flow diagram is as follows Figure 1 As shown,

[0084] Mixing: Weigh the Si3N4 powder and sintering aid according to the formula in Table 1, place them in a ball mill jar, and ball mill them for 12 hours with anhydrous ethanol as the medium. After drying, sieve to obtain a uniform powder mixture.

[0085] Preparation of slurry (according to Table 2): Mix the organic solvent, binder, and plasticizer evenly, then add the dispersant and the above powder mixture and mix well. Ball mill for 24 hours to obtain a uniform and stable silicon nitride casting slurry with a viscosity of 180 mPa·s. After 48 hours, the viscosity is 185 mPa·s, and the slurry performance is stable. Casting and lamination: Degas the silicon nitride casting slurry under vacuum in a casting machine, then cast and cut to obtain silicon nitride casting sheets with a thickness of 0.3 mm. Drilled casting sheets with a diameter of 1 mm are obtained to obtain drilled silicon nitride casting sheets. The drilled silicon nitride casting sheets are stacked to obtain silicon nitride green sheets.

[0086] Warm isostatic pressing: The laminated silicon nitride green wafers were placed in a plastic sealing bag and vacuum sealed, and then subjected to warm isostatic pressing (temperature: 80℃, pressure: 30MPa, time: 90min) to obtain silicon nitride green blocks. The test results showed that the density uniformity of the green blocks was ≥99% and the crack rate was <0.1%.

[0087] Debinding and sintering: The pressed silicon nitride green blocks are debinded and sintered under a nitrogen atmosphere. Debinding stage: The temperature is increased to 450℃ at 1℃ / min and held for 6 hours; Sintering stage: The temperature is increased to 1700℃ at 5℃ / min and held at 1700℃ for 3 hours, and then cooled with the furnace to obtain dense silicon nitride ceramics resistant to plasma corrosion.

[0088] Examples 5-6: Preparation of silicon nitride ceramics resistant to plasma corrosion

[0089] Formulation: The specific raw material molar percentage composition is shown in Table 1; the auxiliary agent molar composition is shown in Table 2.

[0090] Preparation process: The process flow diagram is as follows Figure 1 As shown,

[0091] Mixing: Weigh the Si3N4 powder and sintering aid according to the formula in Table 1, place them in a ball mill jar, and ball mill them for 12 hours with anhydrous ethanol as the medium. After drying, sieve to obtain a uniform powder mixture.

[0092] Preparation of slurry (according to the dosage in Table 2): Mix the organic solvent, binder and plasticizer evenly, then add the dispersant and the above powder mixture and mix well. Ball mill for 24 hours to obtain a uniform and stable silicon nitride casting slurry with a viscosity of 200 mPa·s. After 48 hours, the viscosity is 210 mPa·s, and the slurry performance is stable.

[0093] Casting and lamination: The silicon nitride casting slurry is degassed under vacuum in a casting machine, then cast and cut to obtain a silicon nitride cast sheet with a thickness of 0.6 mm. The perforated cast sheet has a diameter of 3 mm, resulting in a perforated silicon nitride cast sheet. The perforated silicon nitride cast sheets are then stacked to obtain a silicon nitride green sheet.

[0094] Warm isostatic pressing: The laminated silicon nitride green sheets were placed in a plastic bag and vacuum sealed, and then subjected to warm isostatic pressing (temperature: 60℃, pressure: 60MPa, time: 60min) to obtain silicon nitride green blocks. The test results showed that the density uniformity of the green blocks was ≥99% and the crack rate was <0.1%.

[0095] Debinding and sintering: The pressed silicon nitride green sheet is debinded and sintered under a nitrogen atmosphere. Debinding stage: The temperature is increased to 650℃ at 1℃ / min and held for 6 hours; Sintering stage: The temperature is increased to 1850℃ at 5℃ / min and held at 1850℃ for 4 hours, and then cooled in the furnace to obtain dense silicon nitride ceramic resistant to plasma corrosion.

[0096] Table 1 Formulation table for Examples 1-6 (Unit: mol%)

[0097]

[0098] Table 2. Additive formulations (molar amounts, molar ratios) for Examples 1-6

[0099]

[0100] The present invention prepares silicon nitride ceramics according to the above process flow, and then tests the performance of silicon nitride ceramics in terms of plasma corrosion resistance, Vickers hardness, fracture toughness and coefficient of thermal expansion.

[0101] Preparation of electrostatic chuck: The silicon nitride ceramics prepared in Examples 1-6 are machined and finely polished; ventilation holes, blind holes and mounting holes are formed on the back or inside of the ceramic, and electrode lead-out areas are set in the corresponding areas. After metallization treatment of the lead-out areas, reliable connection of electrode leads is achieved by welding or brazing; the ceramic is bonded, brazed or bolted to the metal base or fluid channel structure to form an integral structure, thus obtaining the electrostatic chuck.

[0102] The silicon nitride ceramics formulated according to Examples 1 to 6 of this invention can be used to prepare silicon nitride plasma etching equipment, gas dispersion disks, nozzles or chamber covers using existing technology methods.

[0103] The test results of various properties of the silicon nitride ceramics in Examples 1-6 of this invention are shown in Table 3.

[0104] Table 3. Test data of various properties of silicon nitride ceramics in Examples 1-6.

[0105]

[0106] In the plasma etching rate test, CF4 and O2 gases were used at flow rates of 40 sccm and 10 sccm, respectively. The etching power was 400 W, the chamber pressure was 30 mTorr, and the etching time was 90 min. During the test, the sample to be etched was placed on the electrode plate, with half of each sample covered by a coverslip and the other half exposed in the etching chamber. The height difference between the covered and uncovered parts was measured using a step meter.

[0107] The Vickers hardness test method refers to the national standard GB / T16534~2009 "Test Method for Room Temperature Hardness of Fine Ceramics" for sample preparation and testing; the fracture toughness test method is the indentation method.

[0108] The test method for the coefficient of thermal expansion is based on the national standard GB / T16535~2008 "Test Method for Linear Thermal Expansion Coefficient of Fine Ceramics". The sample preparation and testing are carried out in accordance with the temperature test range of 25~300℃.

[0109] Data analysis: In the plasma corrosion resistance test, the corrosion rate of all ceramic samples in the examples was ≤49 nm / min, indicating that all samples had good plasma corrosion resistance. Examples 4 and 2 showed better plasma corrosion resistance, which may be related to the high YF3 content in the raw material formulation. In all examples, the Vickers hardness of the samples was ≥14.3 GPa and the fracture toughness was ≥5.8 MPa·m. 1 / 2 As can be seen, all samples exhibit good mechanical properties. In all embodiments, the coefficient of thermal expansion of the samples ranges from 2.7 to 3.1 × 10⁻⁶. -6With a coefficient of thermal expansion of approximately 1000 °C, similar to that of silicon wafers, it can be used as a device in semiconductor equipment that directly contacts the wafer. Example 4 exhibits the best corrosion resistance, combining strong Vickers hardness and fracture toughness, making it widely applicable in plasma-resistant device materials, including gas dispersion disks, nozzles, cover plates, and electrostatic chucks in etching equipment.

[0110] The present invention prepares silicon nitride ceramics according to the above process flow, and prepares two comparative examples. The main difference between the comparative examples and the examples lies in the formulation.

[0111] Comparative Example 1 differs from Example 4 in that all fluorides in Example 4 are replaced with oxides, as shown in Table 4.

[0112] Table 4 Comparative Example 1 Formulation Unit: mol%

[0113]

[0114] Comparative Example 2 differs from Example 4 in that some of the fluorides in Example 4 are replaced with oxides, as shown in Table 5.

[0115] Table 5 Comparative Example 2 Formulations (Unit: mol%)

[0116]

[0117] The test results of various properties of the silicon nitride ceramics of Comparative Examples 1 and 2 of this invention are shown in Table 6.

[0118] Table 6 shows the test results of the silicon nitride ceramics in Comparative Examples 1 and 2.

[0119]

[0120] Compared to Example 4, Comparative Examples 1 and 2 exhibited lower resistance to plasma corrosion, with significantly higher plasma corrosion rates. Furthermore, their plasma resistance increased with increasing fluoride content, which may be related to the presence of fluoride in their crystal structure. The absence or minimal presence of fluoride in the raw materials of Comparative Examples 1 and 2 resulted in the absence or minimal presence of fluoride in the crystal structure itself, leading to a more intense reaction upon contact with plasma. In contrast, Example 4, due to the presence of fluoride in its crystal structure, maintained its original structure upon plasma exposure, thus enhancing its resistance to plasma corrosion.

[0121] The basic physical properties and test methods of the silicon nitride ceramics in Examples 1-6 of this invention are as follows:

[0122] Bulk density and relative density: measured by Archimedes' method of displacement.

[0123] Table 7. Bulk density and relative density of ceramics in Examples 1-6

[0124]

[0125] Microstructure characterization: such as Figure 2 As shown in the scanning electron microscope (SEM) images of Example 4, the grains are mainly rod-shaped with a relatively uniform size distribution, and no abnormally large or excessively fine grains were observed. The β-Si3N4 grains grow along a specific direction to form an interlocking structure, exhibiting typical characteristics of high-density silicon nitride microstructure. This structure helps to improve mechanical properties.

[0126] X-ray diffraction (XRD): such as Figure 3 XRD data showed that all phases were β phase, with full α→β ​​transformation, interlocked grains, and extremely low porosity. This is consistent with the dense SEM image and the relative density of >99%. The dense microstructure makes it difficult for fluorine plasma to penetrate along the grain boundaries.

[0127] Thermal and electrical properties: The test results for thermal conductivity, dielectric constant, and dielectric loss are shown in Table 8.

[0128] Table 8 Thermal conductivity, dielectric constant, and dielectric loss of ceramics in Examples 1-6

[0129]

[0130] Long-term reliability data:

[0131] Fatigue resistance: After 100 thermal cycles (e.g., from -55℃ to 150℃), the material performance degradation was tested, and the results are shown in Table 9.

[0132] Table 9. Performance degradation data of ceramics in Examples 1-6 after 100 thermal cycles.

[0133]

[0134] High-temperature creep properties: to evaluate the deformation stability of materials under long-term high-temperature loads.

[0135] Results: Silicon nitride ceramics have a stable structure and excellent creep resistance. Its creep temperature threshold is about 850-900℃, and considerable creep may only occur above 1000℃, while the operating temperature of semiconductor devices is much lower than this temperature range.

[0136] Table 9 shows that the thermal conductivity change rate of all embodiments is ≤5.2%, indicating minimal thermal conductivity degradation and supporting reliable heat dissipation during long-term operation of semiconductor components. The dielectric constant change rate of all embodiments is ≤5.7%, demonstrating excellent clamping accuracy for components such as electrostatic chucks. The dielectric loss of all embodiments is superior to existing technologies. The data indicates that the material of this invention maintains stability under harsh temperature variations, making it suitable for semiconductor equipment undergoing high-frequency thermal cycling (such as plasma etching machines), extending component lifespan, and exhibiting good performance stability after 100 thermal cycles.

[0137] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A silicon nitride ceramic composition resistant to plasma corrosion, characterized in that, By molar fraction: 85–95 parts silicon nitride, 5–15 parts sintering aid. The sintering aids are YF3, CaF2, CeF4, and AlN, with a molar ratio of 0-5:0-5:0-5:2-5, wherein YF3, CaF2, and CeF4 are not simultaneously 0. The silicon nitride ceramic prepared from the plasma-resistant silicon nitride ceramic composition has a fluorine-containing plasma corrosion rate ≤49 nm / min.

2. A silicon nitride ceramic composition resistant to plasma corrosion, characterized in that, The raw materials in molar proportions are: 85 parts Si3N4, 5 parts YF3, 5 parts MgF2, and 5 parts AlN; or 85 parts Si3N4, 2 parts YF3, 3 parts CaF2, 3 parts MgF2, 3 parts CeF4, 4 parts AlN; or 90 parts Si3N4, 2 parts YF3, 2 parts CaF2, 2 parts MgF2, 2 parts CeF4, 2 parts AlN; or 90 parts Si3N4, 4 parts YF3, 2 parts CaF2, 2 parts CeF4, 2 parts AlN; or 90 parts Si3N4, 5 parts CaF2, 1 part MgF2, 2 parts CeF4, 2 parts AlN; The silicon nitride ceramic prepared from the plasma-resistant silicon nitride ceramic composition has a fluorine-containing plasma corrosion rate ≤49 nm / min.

3. A silicon nitride casting slurry, characterized in that, Contains the plasma-resistant silicon nitride ceramic composition as described in claim 1 or 2. The viscosity of the casting slurry is 180–240 mPa·s; It also includes 30-50 moles of organic solvent, 1-5 moles of binder, 0.5-2 moles of plasticizer and 0.5-3 moles of dispersant; The adhesive is a polyvinyl alcohol C1-C4 alkyl aldehyde; and / or The plasticizer is a diC1-C4 alkyl phthalate and / or polyethylene glycol; and / or The organic solvent is a C1-C4 alkyl alcohol, a C3-C4 ketone, and / or isopropanol; and / or The dispersant is a tri(C1-C4) alkyl phosphate and / or fish oil.

4. The silicon nitride casting slurry according to claim 3, characterized in that, The molar composition of the organic solvent, the binder, the plasticizer, and the dispersant is as follows: A mixed solvent of 30 parts each of butanone and anhydrous ethanol in a molar ratio of 2:1; 3 parts polyvinyl butyral; 1.5 parts dibutyl phthalate; and 3 parts triethyl phosphate in a molar ratio; or A mixture of 50 parts isopropanol and anhydrous ethanol in a 1:1 molar ratio, 1 part polyvinyl butyral, 0.5 parts polyethylene glycol, and 1.5 parts fish oil; or The mixture consists of 38 parts of a mixed solvent composed of methyl ethyl ketone, isopropanol, and anhydrous ethanol in a molar ratio of 1:2:3; 5 parts of polyvinyl butyral; 2 parts of a plasticizer mixture composed of dibutyl phthalate and polyethylene glycol in a molar ratio of 1:1; and 3 parts of a dispersant mixture composed of triethyl phosphate and fish oil in a molar ratio of 2:

3.

5. A silicon nitride cast wafer, characterized in that, The film comprises the silicon nitride casting paste according to claim 3 or 4, wherein the thickness of the cast sheet is 0.3 to 0.6 mm.

6. A silicon nitride green sheet, characterized in that, It includes the silicon nitride casting paste as described in claim 3 or 4, or the silicon nitride casting sheet as described in claim 5.

7. A silicon nitride green block, characterized in that, It includes the silicon nitride casting paste as described in claim 3 or 4, the silicon nitride casting sheet as described in claim 5, and the silicon nitride green sheet as described in claim 6.

8. A silicon nitride ceramic resistant to plasma corrosion, characterized in that, It includes the silicon nitride casting slurry as described in claim 3 or 4, or the silicon nitride casting sheet as described in claim 5, or the silicon nitride green sheet as described in claim 6, or the silicon nitride green block as described in claim 7.

9. The method for preparing plasma-resistant silicon nitride ceramic according to claim 8, characterized in that, Includes the following steps: (1) Silicon nitride is mixed with sintering aids to obtain a primary mixture; (2) The binder, plasticizer and organic solvent are mixed to obtain a solvent mixture. The primary mixture is then mixed with the solvent mixture and dispersant and ball-milled to obtain a silicon nitride green sheet casting slurry. (3) After degassing the casting slurry, casting, and cutting, silicon nitride casting sheets are obtained; (4) Drill holes in the silicon nitride cast wafer, stack them to obtain silicon nitride green wafers, and then perform warm isostatic pressing to obtain silicon nitride green blocks; (5) The silicon nitride green block is debinded and sintered to obtain silicon nitride ceramic resistant to plasma corrosion; The thickness of the silicon nitride cast sheet is 0.3–0.6 mm; and / or The diameter of the holes in the silicon nitride cast wafer is 1–3 mm; and / or The isostatic pressing is performed at a temperature of 60–80°C, a pressure of 30–60 MPa, and a time of 60–90 min; and / or The glue removal temperature is 450–650℃, and the glue removal holding time is 6–8h; the sintering temperature is 1700–1850℃, and the sintering temperature holding time is 2–4h.

10. An electrostatic chuck, characterized in that, The raw material comprises the silicon nitride casting slurry as described in claim 3 or 4, or the silicon nitride casting sheet as described in claim 5, or the silicon nitride green sheet as described in claim 6, or the silicon nitride green block as described in claim 7, or is made of the plasma-resistant silicon nitride ceramic as described in claim 8.

11. A semiconductor device component, characterized in that, The raw material comprises the silicon nitride casting slurry as described in claim 3 or 4, or the silicon nitride casting sheet as described in claim 5, or the silicon nitride green sheet as described in claim 6, or the silicon nitride green block as described in claim 7, or is made of the plasma-resistant silicon nitride ceramic as described in claim 8; The semiconductor equipment components are plasma etching equipment, gas dispersion disks, nozzles, or chamber covers.

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