Silicon nitride ceramic composition, ceramic body, electrostatic chuck, preparation method and semiconductor manufacturing equipment

Abstract

The invention relates to the technical field of semiconductor ceramic materials, and discloses a silicon nitride ceramic composition, a ceramic body, an electrostatic chuck, a preparation method and semiconductor manufacturing equipment, the silicon nitride ceramic composition provided by the invention comprises the following raw materials in parts by mole: 85-95 parts of Si3N4, 2-10 parts of a sintering aid and 2-5 parts of a transition metal oxide, the sintering aid comprises a metal fluoride sintering aid. According to the silicon nitride ceramic composition provided by the invention, the heat conductivity (gt, 75W. M <-1 >. K <-1 >) and the mechanical properties (bending strength gt, 900MPa, fracture toughness gt, 6.0 MPa.m < 1 / 2 >) of the material are improved through synergistic interaction of the basic components, and synergistic improvement of corrosion resistance, heat conductivity and electrical properties is realized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor ceramic materials technology, specifically to a silicon nitride ceramic composition, a ceramic body, an electrostatic chuck and its preparation method, and semiconductor manufacturing equipment. Background Technology

[0002] Electrostatic chucks, as one of the core components of semiconductor precision manufacturing equipment, are widely used in equipment such as plasma etching platforms (ETCH), physical vapor deposition (PVD) equipment, and chemical vapor deposition (CVD) equipment. Electrostatic chucks can achieve electrostatic adsorption and heating functions through internal electrodes of a ceramic substrate, enabling stable clamping of wafers while maintaining high stability, low particle size, and high temperature uniformity.

[0003] The electrostatic chuck structure mainly consists of a ceramic layer and a metal base. The ceramic layer comprises a dielectric layer, a heating electrode layer, and an adsorption electrode layer, providing both heating and adsorption functions. The metal base is made of aluminum or stainless steel with built-in cooling gas and liquid flow channels, providing both support and cooling functions. A structural diagram is shown below. Figure 1 As shown. Currently, the global electrostatic chuck market is highly monopolized by American and Japanese manufacturers such as Applied Materials, Lam Research, SHINKO, TOTO, and NTK. The ceramic materials in their mainstream products are mostly alumina (Al2O3) or aluminum nitride (AlN) ceramics.

[0004] As chip linewidths continue to shrink, device integration density increases, and silicon wafer sizes grow larger, plasma power in semiconductor equipment also rises accordingly. This causes Al2O3 and AlN ceramic materials to become less durable under conditions such as carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), and chlorine (Cl2). Prolonged operation under strong plasma etching or corrosive conditions can lead to corrosion, pulverization, and peeling of the ceramic surface, resulting in insufficient corrosion resistance. This, in turn, affects wafer adsorption stability, surface cleanliness, and equipment reliability.

[0005] Meanwhile, heating is one of the functions of an electrostatic chuck, which requires the ceramic material to have good thermal conductivity. Al2O3 ceramics have relatively low thermal conductivity (15–35 W·m). -1 ·K -1 This reduces the efficiency of Al2O3 ceramic electrostatic chucks to some extent. While AlN ceramic materials have higher thermal conductivity (100–230 W·m), this is a different story. -1 ·K -1 However, it has poor mechanical strength and thermal shock resistance, and is prone to deliquescence.

[0006] Silicon nitride (Si3N4) ceramic materials not only possess excellent corrosion resistance, but also have a theoretical thermal conductivity of 200–300 W·m. -1 ·K -1 Due to the presence of lattice defects, its actual thermal conductivity is 30–100 W·m. -1 ·K -1 Silicon nitride (SiN4) ceramics fall between Al2O3 and AlN ceramics. Furthermore, SiN4 ceramics possess advantages such as high melting point, high hardness, wear resistance, high flexural strength, and a thermal expansion coefficient similar to Si. These advantages make SiN4 ceramics a promising candidate material for electrostatic chucks, offering high corrosion resistance and good thermal conductivity. However, SiN4 ceramics themselves have a relatively high resistivity (typically 10 Ω·cm). 13 ~10 16 Furthermore, silicon nitride ceramics have a resistivity of Ω·cm and their electrical properties are not adjustable, thus they cannot meet the requirements for controllable resistivity in semiconductor devices. Chinese invention patent CN118125834A discloses a silicon nitride ceramic with adjustable resistivity, its preparation method, and its application. However, this invention only studies the corrosion behavior of silicon nitride ceramics in liquid chemical media (hydrochloric acid, NaOH, HF, molten salts, etc.), and does not address the corrosion mechanism under plasma conditions. Additionally, although this invention uses rare earth fluorides (such as CeF3) as sintering aids, the corrosion is actually exacerbated in highly corrosive environments such as hydrofluoric acid, indicating that fluoride systems have insufficient stability in harsh environments. This has led to a widespread technical prejudice in the industry that "fluorides are not conducive to plasma corrosion resistance." Moreover, this invention does not consider the requirement for controllable resistivity in semiconductor devices, making it difficult to meet the application requirements in electrostatic chucks. Therefore, the application of Si3N4 ceramics in electrostatic chucks has been stagnant for a long time, and the market is still monopolized by Al2O3 ceramics and AlN ceramics. Therefore, developing a silicon nitride ceramic composition with adjustable resistivity, good thermal conductivity and resistance to plasma corrosion has become a key issue that urgently needs to be addressed. Summary of the Invention

[0007] This invention provides a silicon nitride ceramic composition, a ceramic body, an electrostatic chuck and its preparation method, and semiconductor manufacturing equipment to solve the problems of high resistivity, uncontrollable resistivity, and instability in plasma environment of Si3N4 ceramics in the prior art.

[0008] In a first aspect, the present invention provides a silicon nitride ceramic composition, wherein, by molar amount, the raw materials include: 85-95 parts of Si3N4, 2-10 parts of sintering aid, and 2-5 parts of transition metal oxide, wherein the sintering aid is a metal fluoride sintering aid.

[0009] In one optional embodiment, the metal fluoride sintering aid is a Group IIIB or IIA metal fluoride; and / or

[0010] The transition metal oxides are group IVB and group VIII transition metal oxides; Optionally, the sintering aid further includes metal nitrides; Optionally, the sintering aid is a combination of Group IIIB, IIA metal fluoride sintering aids and / or metal nitride sintering aids.

[0011] In one optional embodiment, the metal fluoride is YF3, CaF2, MgF2, and / or CeF4; and / or The metal nitride is aluminum nitride, and the molar ratio of the metal fluoride to aluminum nitride is (3-5):(1-2); and / or The transition metal oxide is TiO2, Fe2O3 and / or Co3O4.

[0012] In one optional embodiment, the raw material molar ratio is: 85-95 parts Si3N4, 0-4 parts YF3, 0-2 parts CaF2, 0-2 parts MgF2, 0-2 parts CeF4, 0-2 parts AlNO2, 0-5 parts TiO2, 0-5 parts Co3O4, and 0-2 parts Fe2O3. Optional, the raw material molar ratio is: 490 parts Si3N, 32 parts YF, 1 part MgF, 42 parts CeF, 2 parts AlN, and 3 parts TiO; or 85 parts Si3N; 34 parts YF; 22 parts CaF2; 22 parts MgF2; 22 parts CeF4; 25 parts TiO; or 490 parts Si3N; 32 parts YF; 1 part CaF2; 22 parts MgF2; 5 parts Co3O; or 490 parts Si3N; 32 parts YF; 22 parts CaF; 42 parts CeF; 2 parts AlN; 2 parts Fe2O3; or 495 parts Si3N; 1 part CaF2; 2 parts MgF2; 2 parts TiO2; or 95 parts of Si3N4; 1 part of YF3; 1 part of MgF2; 2 parts of TiO2; 1 part of Fe2O3.

[0013] In a second aspect, the present invention provides a silicon nitride ceramic body comprising the above-described ceramic composition.

[0014] In one optional embodiment, it further includes 0.5-3 moles of dispersant, 1-5 moles of binder, 0.5-2 moles of plasticizer, and 30-50 moles of organic solvent; Optionally, the dispersant is a triC1-C4 alkyl phosphate and / or fish oil; and / or 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 or a C3-C4 alkyl ketone. Optionally, the dispersant is triethyl phosphate and / or fish oil; and / or The adhesive is polyvinyl butyral; and / or The plasticizer is dibutyl phthalate and / or polyethylene glycol; and / or The organic solvent is ethanol, butanone, and / or isopropanol; and / or Optionally, the organic solvent, the binder, the plasticizer, and the dispersant are composed of the following molar composition: 50 parts of a mixed solvent consisting of methyl ethyl ketone, isopropanol, and anhydrous ethanol in a molar ratio of 2:1:1; 1 part of polyvinyl butyral; 0.5 parts of dibutyl phthalate; and 3 parts of a dispersant mixture consisting of triethyl phosphate and fish oil in a molar ratio of 1:0.5-23. Alternatively, the molar composition of the organic solvent, the binder, the plasticizer, and the dispersant may be as follows: 40 parts of a mixed solvent consisting of isopropanol and anhydrous ethanol in a molar ratio of 2:1; 5 parts of polyvinyl butyral; 2 parts of a plasticizer mixture consisting of dibutyl phthalate and polyethylene glycol in a molar ratio of 1:0.3-13; and 0.5 parts of fish oil. Alternatively, the molar composition of the organic solvent, the binder, the plasticizer, and the dispersant may be: 30 parts of a mixed solvent consisting of butanone and anhydrous ethanol in a molar ratio of 1:2, 3 parts of polyvinyl butyral, 1 part of polyethylene glycol, and 2 parts of triethyl phosphate.

[0015] Thirdly, the present invention provides an electrostatic chuck comprising the above-described ceramic composition, or comprising the above-described ceramic body.

[0016] Fourthly, the present invention provides a method for preparing the above-mentioned electrostatic chuck, comprising the following steps: (1) Silicon nitride is mixed with sintering aids and transition metal oxides to obtain a primary mixture; (2) The binder, plasticizer, organic solvent, the primary mixture and dispersant are ball-milled and mixed to obtain silicon nitride casting slurry; (3) After degassing the casting slurry, cast and cut the film to obtain silicon nitride cast sheets; (4) Drill holes in the silicon nitride tape to obtain a drilled tape. Stack the drilled tape and the electrode layer tape to obtain a silicon nitride green sheet. Then perform warm isostatic pressing to obtain a silicon nitride green block. (5) The silicon nitride green block is debinded and sintered to form a silicon nitride ceramic body; (6) Machining the silicon nitride ceramic body, welding the electrode leads, and bonding or brazing it with the metal base or fluid channel structure to form an electrostatic chuck.

[0017] In one optional embodiment, the viscosity of the casting slurry is 200±50 mPa·s; the thickness of the silicon nitride cast sheet is 0.3–0.6 mm, and the perforation diameter is 1–3 mm; and / or, The isostatic pressing (WHP) treatment of silicon nitride green wafers 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 temperature for debinding the silicon nitride green block is 450–650℃, and the holding time is 6–8 hours; and / or The sintering temperature is 1700-1850℃, and the holding time at the sintering temperature is 2-4 hours.

[0018] Fifthly, the present invention also provides a semiconductor manufacturing apparatus comprising the aforementioned electrostatic chuck.

[0019] In one alternative embodiment, the semiconductor manufacturing equipment includes an etching machine, a PVD machine, and a CVD machine.

[0020] The technical solution of this invention has the following advantages: 1. The silicon nitride ceramic composition provided by this invention successfully increases the resistivity of the originally insulating Si3N4 ceramic from 10¹³ to 10¹³ by introducing a transition metal oxide. 6 Ω·cm was reduced and stabilized at 10 8 Within the range of ~10¹³ Ω·cm, the specific resistivity requirements of the JR-type electrostatic chuck are met. This invention uses metal fluorides as sintering aids, forming stable grain boundary phases in a fluorine-containing plasma environment. This reduces the corrosion rate of the material by nearly 8 times compared to traditional AlN ceramics or comparative samples using oxide aids (Comparative Example 1, 224 nm / min), overcoming the technical bias that "fluorides are unstable in plasma." The basic formulation of this invention synergistically improves the thermal conductivity of the material (>75 W·m). -1 ·K -1 ) and mechanical properties (flexural strength > 900 MPa, fracture toughness > 6.0 MPa·m) 1 / 2 This achieves a synergistic improvement in corrosion resistance, thermal conductivity, and electrical properties.

[0021] 2. The silicon nitride ceramic composition provided by this invention uses specific metal fluorides from Group IIIB and IIA metals, and transition metal oxides from Group IVB and VIII metals. The synergistic effect of these two materials more effectively promotes densification and the formation of stable grain boundaries during sintering, which is beneficial for improving thermal conductivity. The introduction of AlN further suppresses the formation of the glassy phase at grain boundaries and optimizes the heat transfer path. As shown in Example 4, after adding 2% AlN, the thermal conductivity increased from 76.4 W·m⁻¹. -1 ·K -1 (Example 1) Increased to 86.9 W·m -1 ·K -1 Furthermore, the selected YF3 and CeF4, while providing fluorine sources to enhance corrosion resistance, can effectively reduce the sintering temperature. TiO2 is one of the most effective transition metal oxides for adjusting resistivity; limiting the molar ratio of fluoride to AlN to (3-5):(1-2) can maximize the improvement of thermal conductivity and mechanical strength while ensuring excellent corrosion resistance, and avoid the risk of deliquescence caused by excessive AlN or the adverse effects of excessive fluoride on sintering.

[0022] 3. The specific proportions in the silicon nitride ceramic composition provided by this invention are the optimal solutions selected from a large number of experiments, directly corresponding to the excellent performance data described in Examples 1-6 of the specification (such as high adsorption force, low corrosion rate, suitable resistivity, and high thermal conductivity; for example, the formula "Si3N4 90 parts, YF3 2 parts, MgF2 1 part, CeF4 2 parts, AlN 2 parts, TiO2 3 parts" (corresponding to Example 4) achieves a corrosion rate of 32.3 nm / min and a thermal conductivity of 86.9 W·m). -1 ·K -1 Resistivity 1.2×10 9 The optimal balance is within the experimental range of Ω·cm.

[0023] 4. The silicon nitride ceramic body provided by the present invention directly possesses all the excellent properties endowed by the above-mentioned ceramic composition, namely, high resistance to plasma corrosion, adjustable resistivity, high thermal conductivity, high mechanical strength and toughness, and is the core component for manufacturing high-performance electrostatic chucks.

[0024] 5. The additives and their specific proportions in the silicon nitride ceramic body provided by this invention ensure that a casting slurry with stable viscosity and uniform dispersion can be prepared; the optimized additive system can reduce particle agglomeration and improve the strength of the green body; the thickness of the cast sheet is uniform (0.3~0.6mm), which facilitates subsequent drilling, stacking and warm isostatic pressing, thereby obtaining a high density (>99%), defect-free ceramic green body, which is suitable for mass production process and has a yield rate of ≥95%.

[0025] 6. The silicon nitride electrostatic chuck provided by the present invention adopts the above-mentioned high-performance ceramic body or ceramic composition, and has high reliability, long life and excellent performance, specifically manifested in: high adsorption force, thermal expansion coefficient matching silicon wafer (avoiding thermal stress cracking), excellent temperature uniformity and long-term stability under harsh semiconductor manufacturing environment (such as plasma etching).

[0026] 7. The electrostatic chuck preparation method provided by the present invention can obtain high-performance, large-size, complex-structured ceramic bodies with uniform microstructure and high density through the optimized tape casting-warm isostatic pressing-gas pressure sintering process.

[0027] 8. The electrostatic chuck preparation method provided by the present invention uses isostatic pressing (60-80℃, 30-60MPa) to effectively eliminate interlayer bubbles and increase the density of the blank; gradient debinding (450-650℃) reduces the risk of internal stress cracking; and gas pressure sintering (N2, 2-5MPa, 1700-1850℃) inhibits Si3N4 decomposition and promotes densification.

[0028] 9. The semiconductor manufacturing equipment provided by this invention includes an electrostatic chuck made of silicon nitride. Components made of this material can significantly enhance the tolerance of the core clamping components of the equipment to plasma, corrosive gases, and high-temperature process environments, thereby improving the long-term operational stability and service life of the entire semiconductor manufacturing equipment. The silicon nitride electrostatic chuck has excellent thermal and chemical stability, enabling it to provide more stable and uniform clamping and temperature control for wafers in processes such as etching and thin film deposition, which is beneficial for ensuring the consistency of process results within and between batches. Silicon nitride material has the characteristics of low gas release, high purity, and corrosion resistance, which can effectively reduce particulate contamination and metal contamination caused by the chuck material itself in vacuum and plasma environments, thereby improving product yield.

[0029] 10. The semiconductor manufacturing equipment provided by the present invention includes an etching machine, a PVD machine, and a CVD machine. In the etching machine, it can withstand stronger corrosive process gases and achieve more precise etching control. In the PVD machine, it can operate stably at higher temperatures, improving film adhesion and uniformity. In the CVD machine, it can withstand the erosion of chemical precursors, ensuring the purity and stability of the deposition process. Attached Figure Description

[0030] 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.

[0031] Figure 1This is a schematic diagram of the electrostatic chuck structure of the present invention; Figure 2 This is a process flow diagram for preparing the ceramic body for the electrostatic chuck of the present invention; Figure 3 This is a 3kx magnified SEM image of the ceramic surface in Example 1. Detailed Implementation

[0032] 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.

[0033] 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.

[0034] Examples 1-6: Preparation and Properties of Silicon Nitride Ceramic Bodies and Electrostatic Chucks 1. Raw material formulation: The molar ratios of the basic raw materials in Examples 1-6 are shown in Table 1 (unit: mol parts). Table 1: Ceramic body formulations of Examples 1-6

[0035] Table 2. Additive formulations (molar amounts, molar ratios) for Examples 1-6

[0036] 2. Preparation process steps All embodiments follow the procedure described below (see attached instruction manual). Figure 2 (Process flow diagram) Mixing: The Si3N4 powder in the proportions in Table 1, sintering aids (metal fluorides, AlN) and transition metal oxides are ball-milled and mixed according to the formula in Table 1 for 16-20 hours. The mixture is dried using anhydrous ethanol as the medium and then sieved to obtain a homogeneous mixture.

[0037] Preparation of slurry: According to the component ratio in Table 2, mix the mixture with dispersant, binder, plasticizer and organic solvent, and ball mill for 16-20 hours to form cast slurry (viscosity controlled at 200±50mPa·s).

[0038] Casting and lamination: After vacuum degassing, the slurry is cast into a ceramic sheet with a thickness of 0.3-0.6mm and cut into 400-480mm square cast sheets.

[0039] Holes (1-3mm in diameter) are punched in the cast film, and heating electrode layer and adsorption electrode layer are prepared by tungsten paste screen printing.

[0040] The perforated cast sheet and the electrode layer cast sheet are stacked to form an electrostatic chuck green sheet (thickness 6-8mm).

[0041] Warm isostatic pressing: The green sheet is held at 60-80℃ and 30-60MPa for 60-90 minutes to obtain the green block.

[0042] Debinding and sintering: Glue removal: Keep at 450-650℃ for 6-8 hours to remove organic matter.

[0043] Sintering: Under N2 atmosphere, at a pressure of 2-5 MPa, sinter at 1700-1850℃ for 2-4 hours to obtain a dense silicon nitride ceramic body (relative density ≥99%).

[0044] Electrostatic chuck preparation: The above-mentioned ceramic body is machined and finely polished; ventilation holes, blind holes and mounting holes are formed on the back or inside of the ceramic body, and electrode lead-out areas are set in the corresponding areas. After the lead-out areas are metallized, the electrode leads are reliably connected by welding or brazing; the ceramic body is bonded, brazed or bolted to the metal base or fluid channel structure to form an integral structure, thus obtaining the electrostatic chuck.

[0045] 3. Performance test results: Performance tests were conducted on the silicon nitride ceramic bodies of Examples 1-6.

[0046] Test conditions: Adsorption force: 2kV DC voltage, vacuum environment, measured after stabilization for 1 minute.

[0047] Etching rate: CF4 and O2 mixed gas (40 / 10 sccm), 300W plasma power, 30 mTorr pressure, etching for 90 minutes. During testing, 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. A profilometer was used for the measurement.

[0048] Resistivity / thermal conductivity: Refer to GB / T5593-2015 and GB / T39862-2021 standards.

[0049] Mechanical properties: Strength was measured by the three-point bending method, and fracture toughness was measured by the indentation method.

[0050] SEM (Semiconductor Microscopy) testing: The silicon nitride ceramic body of Example 1 was tested using electron microscopy, with surface magnification of 3kx. (See attached image) Figure 3 .

[0051] Key performance data of silicon nitride ceramic bodies in Examples 1-6 are shown in Table 3: Table 3 Performance data of silicon nitride ceramic bodies in Examples 1-6

[0052] 4. Key Feature Data Analysis Table 3 shows that in all embodiments, the adsorption force of all silicon nitride ceramic bodies is ≥78 gf / cm² under a DC voltage of 2 kV. 2 It can be seen that all silicon nitride ceramic bodies have good adsorption capacity; the plasma corrosion rate of silicon nitride ceramic bodies is <50 nm / min, indicating that all silicon nitride ceramic bodies have good resistance to plasma corrosion; in all embodiments, the resistivity of silicon nitride ceramic bodies is within 10. 8 ~10 13 Ω·cm, meeting the resistivity requirements of JR type electrostatic chucks; the thermal conductivity of all embodiments is >75 W·m. -1 ·K -1 As can be seen, all silicon nitride ceramic bodies have good thermal conductivity. Among them, the silicon nitride ceramic body with the best corrosion resistance is Example 4, which has the best resistance to plasma corrosion and the highest thermal conductivity.

[0053] Thermal and mechanical properties: The thermal conductivity of the silicon nitride ceramic bodies in Examples 1-6 is >75 W / m·K, ensuring wafer temperature uniformity; the flexural strength is >900 MPa; and the fracture toughness is >6.0 MPa·m. 1 / 2 .

[0054] Coefficient of thermal expansion: The coefficients of thermal expansion of the silicon nitride ceramic bodies in Examples 1-6 are 3.2-3.9 × 10⁻⁶ respectively. -6 / ℃, 3.5×10 -6 / ℃, 3.2×10 -6 / ℃, 3.7×10 -6 / ℃, 3.3×10 -6 / ℃, 3.9×10 -6 / ℃, 3.4×10 -6 / ℃, (CTE, 25-400℃), with silicon wafers (3.0×10 -6 ( / ℃) Highly matched.

[0055] SEM images show that the silicon nitride ceramic body of Example 1 has no visible interconnecting pores on its surface and the open porosity is close to zero. Combined with the previous relative density, it can be seen that the silicon nitride ceramic body of Example 1 is dense and has closed pores, which can effectively block plasma penetration.

[0056] Comparative Example 1. The fluoride sintering aid in Example 1 was replaced with oxides (Y2O3, MgO, CaO, CeO2), and the formula was: Si3N4 85 mol%, Y2O3 4%, MgO 2%, CaO 2%, CeO2 2%, TiO2 5%.

[0057] Comparative Example 2. The transition metal oxides (TiO2, etc.) were removed, and the formula was adjusted to: Si3N4 89.474 mol%, YF3 4.211%, MgF2 2.105%, CaF2 2.105%, CeF4 2.105%.

[0058] Table 4 Performance data of comparative samples

[0059] Results analysis: Comparative Example 1: The oxide sintering aid lacked fluorine grain boundary protection, resulting in a surge in corrosion rate (224 nm / min) and a decrease in thermal conductivity (65.2 W / m·K).

[0060] Comparative Example 2: No transition metal oxide doping, excessively high resistivity (10¹) 4 The adsorption capacity is insufficient (24 gf / cm²), which cannot meet the requirements of the electrostatic chuck.

[0061] Compared to Example 1, Comparative Example 1 exhibits a higher plasma corrosion rate, which may be related to the absence of fluorine (F) in its crystal structure. Since the structure itself lacks F, its reaction with plasma is more intense. In contrast, in Example 1, the presence of F in the crystal structure allows it to maintain its original structure upon plasma exposure. Compared to Example 1, Comparative Example 2 exhibits higher resistivity and lower adsorption force, which may be due to the absence of transition metal oxides in its composition, leading to uncontrolled resistivity (10⁻⁶). 14 (Ω·cm). Transition metal oxides can reduce the volume resistivity of ceramics to a certain extent, making charge movement in the electrostatic chuck ceramic relatively easier, thereby enhancing the adsorption force of the JR type electrostatic chuck. The inventors of this invention control the resistivity of the product by adjusting the doping amount of TiO2, etc., to meet the requirements of the JR type electrostatic chuck.

[0062] The corrosion rate of silicon nitride ceramic bodies in all embodiments of the present invention is reduced by 4-8 times compared with the comparative example. This is because the synergistic effect of the fluoride sintering aid with a specific composition in Example 1 forms an extremely stable barrier phase at the grain boundaries of the material that can effectively resist fluorine plasma erosion. This unique microstructure allows the material to change from an easily corroded "active" state to a stable "passivated" state when facing fluorine plasma, thereby achieving a significant reduction in the corrosion rate.

[0063] Thermal and mechanical properties: The thermal conductivity of the silicon nitride ceramic bodies in Examples 1-6 is more than 100% higher than that of Al2O3 (15-35 W / m·K), ensuring wafer temperature uniformity. The bending strength is >900 MPa and the fracture toughness is >6.0 MPa·m. 1 / 2 Both are superior to traditional Al2O3 and AlN ceramics.

[0064] Table 5. Relative density and bulk density of silicon nitride ceramic bodies in Examples 1-6

[0065] Table 5 shows that the bulk density of the silicon nitride ceramic bodies prepared in the embodiments of the present invention ranges from 3.1662 to 3.2451 g / cm³ (the lowest in Example 5 and the highest in Example 1); the relative density of the silicon nitride ceramic bodies prepared in the embodiments of the present invention is all higher than 99.1% (the lowest being 99.176% in Example 3 and the highest being 99.330% in Example 1). Table 5 illustrates that the silicon nitride ceramic bodies of the present invention have an extremely high degree of densification: the relative density of all embodiments is close to the theoretical limit (≥99.1%), indicating that the sintering process of the present invention has successfully achieved a highly dense microstructure. High density directly reduces porosity, which is beneficial to improving the mechanical strength, thermal conductivity and corrosion resistance of the material; in addition, the relative density fluctuation range is small (99.176%–99.330%), proving that the formulation and sintering parameters of the present invention have good repeatability and controllability.

[0066] Potential comparison with comparative examples: The densification of the embodiments of the present invention is significantly superior to that of conventional processes.

[0067] The dielectric constant (Dk) and dielectric loss (Df) of the silicon nitride ceramic bodies in Examples 1-6 of this invention were measured at 1 MHz. Table 6. Dielectric constants and dielectric losses of silicon nitride ceramic bodies in Examples 1-6.

[0068] Table 6 shows that the dielectric constant of the silicon nitride ceramic bodies prepared in the embodiments of the present invention ranges from 7.0 to 8.1 (the lowest in Example 3 and the highest in Example 6); the dielectric loss of the silicon nitride ceramic bodies prepared in the embodiments of the present invention is all below 3.4 × 10⁻⁶. - ³. The dielectric constant of 7.0-8.1 is in the low range (compared to Dk≈9-10 for common ceramics such as Al₂O₃), indicating that the material has a weak response to electric fields, making it suitable for high-frequency semiconductor devices (such as plasma etching machines), which can reduce signal delay and energy loss. In addition, all Df values ​​are ≤3.4×10⁻⁶. -3 Approaching the level of an ideal insulator (Df<10) -3Low loss means that the proportion of energy converted into heat under the influence of an electric field is extremely small, making it suitable for high-power equipment and avoiding thermal runaway. Table 6 shows that in Example 1 (Dk=7.8, Df=1.1×10⁻⁶),... -3 Example 6 (Dk=8.1, Df=1.5×10) and Example 7 (Dk=8.1, Df=1.5×10) -3 The outstanding performance may be related to the optimization of TiO2 doping amount (e.g., Example 4 contains 3 parts TiO2, with slightly higher Df), which reflects the tunability of dielectric properties of transition metal oxides.

[0069] Long-term reliability data: Thermal shock (thermal cycling) test: The silicon nitride ceramic bodies of Examples 1-6 of this invention were subjected to 100-200 cycles between -55℃ and 150℃, and the strength retention rate was >90% in all cases. This demonstrates that the thermal shock resistance of the silicon nitride ceramic bodies of Examples 1-6 of this invention is far superior to that of the aluminum nitride ceramic bodies.

[0070] After 100 thermal cycles, the flexural strength retention rates of Examples 1-6 were 93.8%, 95.1%, 93.5%, 94.9%, 93.7%, and 94.2%, respectively. The flexural strength retention rate of conventional sintered aluminum nitride was 80%, and that of high-density aluminum nitride was 85%.

[0071] High temperature and high humidity storage test: The silicon nitride ceramic bodies of Examples 1-6 of the present invention were placed at 85℃ / 85%RH for a certain period of time. The resistivity change rate was detected to be <10%, which proves that the stability of the silicon nitride ceramic bodies of Examples 1-6 of the present invention is better than that of the easily deliquescent aluminum nitride ceramic bodies.

[0072] After the "double 85" test, the resistivity change rates of Examples 1-6 were 3.1%, 2.4%, 3.3%, 2.7%, 3.4%, and 2.7%, respectively. The resistivity showed extremely high stability under high temperature and high humidity conditions, while the resistivity change rate of the high-density AlN ceramic body was 14.2%.

[0073] Process adaptability: The casting-screen printing-warm isostatic pressing process supports mass production of large-size and complex parts with a yield rate of ≥95%.

[0074] Example 4 of this invention (formula molar parts: 490 parts Si3N, 32 parts YF, 1 part MgF2, 42 parts CeF, 2 parts AlN, 3 parts TiO2) exhibits the best overall performance within the experimental range: lowest corrosion rate (32.3 nm / min), highest thermal conductivity (86.9 W / m·K), and moderate resistivity (1.2 × 10⁻⁶). 9 (Ω·cm). Suitable for high-end semiconductor equipment such as plasma etching machines and PVD / CVD chambers, extending the life of electrostatic chucks to ≥1000 hours.

[0075] By comparing the examples and comparative examples, the synergistic effect of metal fluoride sintering aids and transition metal oxide doping was verified, which solved the core pain points of Si3N4 ceramics, namely, the unadjustable resistivity and poor corrosion resistance, and provided a high-performance material solution for key components of semiconductor equipment.

[0076] 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, characterized by, The raw materials include, in terms of mole parts: 85-95 parts of Si3N4, 2-10 parts of sintering aid, 2-5 parts of transition metal oxide, the sintering aid including metal fluoride sintering aid.

2. The silicon nitride ceramic composition of claim 1, wherein, The metal fluoride sintering aid is Group IIIB, Group IIA metal fluoride sintering aid; and / or The transition metal oxide is Group IVB, Group VIII transition metal oxide; At least one of the following is satisfied: The sintering aid further includes metal nitride sintering aid; The sintering aid is a combination of Group IIIB, Group IIA metal fluoride sintering aid and / or metal nitride sintering aid; The metal fluoride sintering aid is YF3, CaF2, MgF2 and / or CeF4; and / or The metal nitride sintering aid is aluminum nitride, and the mole ratio of the metal fluoride sintering aid to aluminum nitride is (3-5):(1-2); and / or The transition metal oxide is TiO2, Fe2O3 and / or Co3O4.

3. The silicon nitride ceramic composition of claim 2, wherein, The mole parts of the raw materials are: 85-95 parts of Si3N4, 0-4 parts of YF3, 0-2 parts of CaF2, 0-2 parts of MgF2, 0-2 parts of CeF4, 0-2 parts of AlN, 0-5 parts of TiO2, 0-5 parts of Co3O4, and 0-2 parts of Fe2O3. At least one of the following is satisfied: The mole parts of the raw materials are: 90 parts of Si3N4, 2 parts of YF3, 1 part of MgF2, 2 parts of CeF4, 2 parts of AlN, and 3 parts of TiO2; or The mole parts of the raw materials are: 85 parts of Si3N4, 4 parts of YF3, 2 parts of CaF2, 2 parts of MgF2, 2 parts of CeF4, and 5 parts of TiO2; or The mole parts of the raw materials are: 90 parts of Si3N4, 2 parts of YF3, 1 part of CaF2, 2 parts of MgF2, and 5 parts of Co3O4; or The mole parts of the raw materials are: 90 parts of Si3N4, 2 parts of YF3, 2 parts of CaF2, 2 parts of CeF4, 2 parts of AlN, and 2 parts of Fe2O3; or The mole parts of the raw materials are: 95 parts of Si3N4, 1 part of CaF2, 2 parts of MgF2, and 2 parts of TiO2; or The mole parts of the raw materials are: 95 parts of Si3N4, 1 part of YF3, 1 part of MgF2, 2 parts of TiO2, and 1 part of Fe2O3.

4. A silicon nitride ceramic body, characterized by, The ceramic composition of any one of claims 1-3.

5. The silicon nitride ceramic body of claim 4, wherein, Further including 0.5-3 mole parts of dispersant, 1-5 mole parts of binder, 0.5-2 mole parts of plasticizer, and 30-50 mole parts of organic solvent; At least one of the following is satisfied: The dispersant is tri-C1-C4 alkyl phosphate and / or fish oil; and / or The binder is polyvinyl C1-C4 alkyl acetal; and / or The plasticizer is di-C1-C4 alkyl phthalate and / or polyethylene glycol; and / or The organic solvent is C1-C4 alkyl alcohol and C3-C4 alkyl ketone; The dispersant is triethyl phosphate and / or fish oil; and / or The binder is polyvinyl butyral; and / or The plasticizer is dibutyl phthalate and / or polyethylene glycol; and / or The organic solvent is ethanol, butanone and / or isopropyl alcohol; and / or At least one of the following is satisfied: The mole parts of the organic solvent, the binder, the plasticizer, and the dispersant are: 50 parts of mixed solvent composed of butanone, isopropanol and anhydrous ethanol in a molar ratio of 2:1:1; 1 part of polyvinyl butyral, 0.5 parts of dibutyl phthalate, 3 parts of dispersant mixture composed of triethyl phosphate and fish oil in a molar ratio of 1:0.5-23; or the molar parts of the organic solvent, the binder, the plasticizer, the dispersant are composed of 40 parts of mixed solvent composed of isopropanol and anhydrous ethanol in a molar ratio of 2:1, 5 parts of polyvinyl butyral, 2 parts of plasticizer mixture composed of dibutyl phthalate and polyethylene glycol in a molar ratio of 1:0.3-13; 0.5 parts of fish oil; or the molar parts of the organic solvent, the binder, the plasticizer, the dispersant are composed of 30 parts of mixed solvent composed of butanone and anhydrous ethanol in a molar ratio of 1:2, 3 parts of polyvinyl butyral, 1 part of polyethylene glycol, 2 parts of triethyl phosphate.

6. An electrostatic chuck, comprising: The silicon nitride ceramic composition of any one of claims 1-3, or the silicon nitride ceramic body of claim 4 or 5.

7. The method of producing an electrostatic chuck according to claim 6, characterized by, The method comprises the following steps: (1) mixing silicon nitride with sintering aids and transition metal oxides to obtain a primary mixture; (2) ball-milling the binder, the plasticizer, the organic solvent, the primary mixture and the dispersant to obtain a silicon nitride tape casting slurry; (3) degassing the tape casting slurry, then tape casting and cutting to obtain a silicon nitride tape casting sheet; (4) punching the silicon nitride tape casting sheet to obtain a punched tape casting sheet, stacking the punched tape casting sheet and an electrode layer tape casting sheet to obtain a silicon nitride green sheet, then performing warm isostatic pressing to obtain a silicon nitride green block; (5) performing degassing and sintering on the silicon nitride green block to form a silicon nitride ceramic body; (6) machining the silicon nitride ceramic body, welding an electrode lead, and bonding or brazing with a metal base or a fluid passage structure to form an electrostatic chuck.

8. The method of claim 7, wherein the electrostatic chuck is prepared by the steps of: The viscosity of the tape casting slurry is 200±50 mPa·s; the thickness of the silicon nitride tape casting sheet is 0.3-0.6 mm, and the diameter of the punched hole is 1-3 mm; and / or The temperature for performing warm isostatic pressing on the silicon nitride green sheet is 60-80℃, the pressure is 30-60 MPa, and the time is 60-90 min; and / or The temperature for performing degassing on the silicon nitride green block is 450-650℃, and the holding time is 6-8 h; and / or The sintering temperature is 1700-1850℃, and the holding time of the sintering temperature is 2-4 h.

9. A semiconductor manufacturing apparatus, characterized by comprising: The electrostatic chuck of claim 6.

10. The semiconductor manufacturing apparatus according to Claim 9, wherein The method comprises an etching machine, a PVD device and a CVD device.

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