Liquid-phase siliconizing densification and surface treatment method of recrystallized SiC sintered body for semiconductor

Abstract

The invention belongs to the technical field of semiconductor core equipment part preparation, and particularly relates to a liquid-phase siliconizing densification and surface treatment method of a recrystallized SiC sintered body for a semiconductor. The method comprises the following steps: firstly, preparing a SiC sintered body by adopting a recrystallization sintering technology, carrying out densification treatment on the recrystallized SiC sintered body by adopting a soaking liquid phase siliconizing method, then reducing the surface roughness by adopting a method of weighting the surface of the crystalline SiC sintered body by adopting a machine and a turbine, and carrying out surface scale removal treatment on the surface of the recrystallized SiC sintered body by using an HF acid aqueous solution. And finally, depositing the SiC protective coating with low surface roughness on the recrystallized SiC sintered body by adopting a chemical vapor deposition method, wherein the thickness of the SiC protective coating is 50-1000 microns. The recrystallized SiC sintered body part is prepared through liquid-phase siliconing densification technology treatment, surface treatment and surface protective coating treatment, and the recrystallized SiC sintered body part has the advantages of being low in surface roughness, high in compactness, high in corrosion resistance, high in mechanical property and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor core equipment parts preparation, and in particular relates to a liquid phase siliconization densification and surface treatment method for a recrystallized SiC sintered body for semiconductors. Background Art

[0002] Silicon carbide (SiC), a third-generation semiconductor material, boasts excellent chemical stability, a wide bandgap, high breakdown voltage, and thermal conductivity. SiC materials prepared using various methods offer excellent overall properties, making them suitable for use as high-temperature structural materials or protective coatings. Recrystallized SiC sintered bodies are widely used in wafer boats, for example, in semiconductor diffusion and annealing processes.

[0003] However, in the field of semiconductor diffusion and annealing, using recrystallized SiC sintered bodies directly as wafer boats presents a major problem: after long-term and frequent thermal shock exposure to temperatures around 1200°C, particles tend to fall off the surface of the recrystallized SiC sintered bodies, causing contamination of the wafer surface. Therefore, the recrystallized SiC sintered bodies need to be densified with silicon to improve their strength, and then coated with a high-purity SiC coating after densification. Summary of the Invention

[0004] The purpose of the present invention is to provide a liquid phase siliconization densification and surface treatment method for recrystallized SiC sintered bodies for semiconductors, so as to solve the problems existing in the direct use of recrystallized SiC sintered bodies in the semiconductor field, such as easy shedding of surface particles, high surface roughness, and low strength.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for liquid-phase siliconizing densification and surface treatment of a recrystallized SiC sintered body for semiconductor use comprises the following steps: using high-purity silicon carbide powder as raw material, preparing a SiC sintered body through a recrystallization sintering technology, sequentially adopting liquid-phase siliconizing densification, surface machining, and surface oxide scale removal with an HF acid aqueous solution; further treating the recrystallized SiC sintered body; and finally, preparing a SiC composite coating on the recrystallized SiC sintered body through a chemical vapor deposition method using methyltrichlorosilane as raw material.

[0007] The liquid phase siliconization densification and surface treatment method of a recrystallized SiC sintered body for semiconductor use comprises the following steps:

[0008] (1) Using high-purity silicon carbide powder as raw material, using recrystallization sintering technology, in Ar atmosphere, sintering temperature of 2200-2500℃, 1-3 standard atmospheres of pressure to prepare silicon carbide with a density of 1.00g / cm 3 ~3.20g / cm 3The bulk density of the recrystallized SiC sintered body is 2.00 g / cm 3 ~3.20g / cm 3 ;

[0009] (2) densification of the recrystallized SiC sintered body by immersion liquid phase siliconizing in an Ar atmosphere at a liquid phase siliconizing temperature of 1450-1600°C and 1-3 standard atmospheres of pressure;

[0010] (3) The surface of the recrystallized SiC sintered body after siliconization is machined using a machining wheel to reduce the surface roughness;

[0011] (4) using an HF acid aqueous solution with a mass fraction of 3% to 30% to remove oxides on the surface of the recrystallized sintered body, and drying the body for later use;

[0012] (5) Using methyltrichlorosilane as raw material, the deposition temperature is 1100-1350°C, the pressure is 1000-10000Pa, and a SiC protective coating with a thickness of 50 μm-1000 μm is deposited on the recrystallized SiC sintered body. After the deposition is completed, the furnace is cooled.

[0013] In the liquid phase siliconization densification and surface treatment method for a recrystallized SiC sintered body for semiconductor use, preferably, in step (1), the sintering temperature is 2400° C. and the pressure is 125,000 Pa.

[0014] In the liquid phase siliconizing densification and surface treatment method for a recrystallized SiC sintered body for semiconductor use, preferably, in step (2), the liquid phase siliconizing temperature is 1550° C. and the pressure is 220,000 Pa.

[0015] In the liquid phase siliconization densification and surface treatment method for a recrystallized SiC sintered body for semiconductor use, preferably, in step (4), the mass fraction of the HF acid aqueous solution is 17%.

[0016] In the liquid phase siliconization densification and surface treatment method for a recrystallized SiC sintered body for semiconductor use, preferably, in step (5), the deposition temperature is 1300° C. and the pressure is 5000 Pa.

[0017] The design idea of the present invention is:

[0018] In response to the problems existing in the prior art, the present invention designs a siliconization densification and surface treatment method for recrystallized SiC materials in semiconductor diffusion and annealing processes, and verifies the effect of its chemical vapor deposition SiC coating. The present invention innovatively combines recrystallization sintering technology, liquid phase siliconization densification technology, surface machining technology, surface pickling technology, and chemical vapor deposition technology to prepare a recrystallized SiC sintered body with a SiC protective coating, and measures the surface roughness of the composite material. The technology involved in the present invention can solve the problems of particle shedding, surface roughness, and low strength of recrystallized SiC sintered bodies that occur during use, and is of great significance to improving the service life of semiconductor core equipment and improving the chip qualification rate.

[0019] The advantages and beneficial effects of the present invention are:

[0020] The recrystallized SiC sintered body with a SiC protective coating prepared by the present invention exhibits advantages such as high density, low surface roughness, strong corrosion resistance, and excellent mechanical properties. Compared with recrystallized SiC sintered bodies prepared by other methods, the recrystallized SiC sintered body composite material prepared by the present invention effectively avoids problems such as particle shedding, surface roughness, and low strength that occur during semiconductor diffusion and annealing processes. This significantly increases the service life and chip qualification rate of core semiconductor equipment, reduces the frequency of component replacement, and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The recrystallization sintering technology was used to prepare a bulk density of 2.64g / cm3 in Ar atmosphere at 2400℃ and 125000Pa pressure. 3 X-ray diffraction (XRD) pattern of SiC sintered body; in the figure, the abscissa 2Theta is the diffraction angle (°), and the ordinate Intensity is the relative intensity (au).

[0022] Figure 2 The recrystallization sintering technology was used to prepare a bulk density of 2.64g / cm3 in Ar atmosphere at 2400℃ and 125000Pa pressure. 3 Surface morphology of SiC sintered body; among them, (a) is the secondary electron image and (b) is the backscattered electron image.

[0023] Figure 3 This is the XRD pattern of a recrystallized SiC sintered body densified by immersion liquid phase siliconization in an Ar atmosphere at 1550°C and a pressure of 220,000 Pa and treated by surface machining. In the figure, the abscissa 2Theta is the diffraction angle (°) and the ordinate Intensity is the relative intensity (au).

[0024] Figure 4These are the surface morphologies of the recrystallized SiC sintered body densified by immersion liquid phase siliconization in an Ar atmosphere at 1550°C and a pressure of 220,000 Pa and processed by surface machining; (a) is the secondary electron image, and (b) is the backscattered electron image.

[0025] Figure 5 These are surface morphologies of the recrystallized sintered body after surface oxides are removed using a 17% by mass HF acid aqueous solution; (a) is a secondary electron image, and (b) is a backscattered electron image.

[0026] Figure 6 This is the XRD pattern of a SiC protective coating with a thickness of approximately 110 μm deposited on a recrystallized SiC sintered body using methyltrichlorosilane (MTS) as the raw material, at a deposition temperature of 1300°C and a pressure of 5000 Pa. In the figure, the abscissa 2Theta is the diffraction angle (°) and the ordinate Intensity is the relative intensity (au).

[0027] Figure 7 This is a cross-sectional morphology of a SiC protective coating with a thickness of approximately 110 μm deposited on a recrystallized SiC sintered body using methyltrichlorosilane as raw material at a deposition temperature of 1300°C and a pressure of 5000 Pa. DETAILED DESCRIPTION

[0028] In the specific implementation process, the present invention proposes a liquid phase siliconization densification and surface treatment method for a recrystallized SiC sintered body for semiconductors, which adopts recrystallization sintering technology, selects high-purity silicon carbide powder, and prepares a recrystallized SiC sintered body with a bulk density of 2.00 g / cm2 in an Ar atmosphere at 2200-2500 °C and 1-3 standard atmospheres. 3 ~3.20g / cm 3 The invention relates to a SiC sintered body having a surface roughness of Ra 0.01 to 0.5 μm and a SiC sintered body having a surface roughness of Ra 0.01 to 0.5 μm, and a SiC sintered body having a surface roughness of Ra 0.01 to 0.5 μm is prepared by using an immersion liquid phase siliconizing method in an Ar atmosphere at 1450 to 1600° C. and 1 to 3 standard atmospheres. The surface of the recrystallized SiC sintered body is then machined by a machining wheel (such as a surface rolling wheel, a surface grinding wheel or a surface honing wheel, etc.) to reduce the surface roughness to Ra 0.01 to 0.5 μm, and the surface of the recrystallized SiC sintered body is subjected to surface oxide scale removal treatment using an HF acid aqueous solution with a mass fraction of 3% to 30%. Finally, a SiC protective coating with a low surface roughness of 50 μm to 1000 μm is deposited on the recrystallized SiC sintered body by a chemical vapor deposition method.

[0029] The immersion liquid phase siliconization method involves melting silicon powder or other silicon-containing raw materials (such as silica sol) as a silicon source at high temperature to form liquid silicon. The recrystallized and sintered SiC sintered body is immersed in the liquid silicon, and pressure is applied to allow the liquid silicon to penetrate the pores of the SiC sintered body, achieving densification.

[0030] The following further describes the specific embodiments of the present invention. It should be noted that the description of these embodiments is intended to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are available through conventional commercial channels unless otherwise specified.

[0032] Example 1

[0033] In this embodiment, a method for liquid-phase siliconization densification and surface treatment of a recrystallized SiC sintered body for semiconductor use comprises the following steps:

[0034] (1) Using high-purity silicon carbide powder (purity ≥99.99 wt%) as raw material, a recrystallization sintering technology was used to prepare a bulk density of 2.64 g / cm3 in an Ar atmosphere at 2400 °C and a pressure of 125000 Pa. 3 SiC sintered body;

[0035] (2) The recrystallized SiC sintered body was densified by immersion liquid phase siliconization in an Ar atmosphere at 1550°C and a pressure of 220000 Pa;

[0036] (3) The surface of the recrystallized SiC sintered body after siliconization was machined using a machining wheel to reduce the surface roughness to Ra0.325μm;

[0037] (4) Using a 17% HF acid aqueous solution to remove oxides on the surface of the recrystallized sintered body, blow dry and set aside;

[0038] (5) Using methyltrichlorosilane as raw material, the deposition temperature is 1300 ° C, the pressure is 5000 Pa, and a SiC protective coating with a thickness of about 110 μm is deposited on the recrystallized SiC sintered body. After the deposition is completed, the furnace is cooled.

[0039] The surface of the recrystallized SiC sintered body treated with liquid-phase siliconization densification in this example is significantly denser, with virtually no pores. Furthermore, after surface machining and pickling, the surface is even smoother and almost free of oxide scale. Consequently, the SiC protective coating deposited on the recrystallized SiC sintered body has a relatively smooth surface.

[0040] Example 2

[0041] In this embodiment, a method for liquid-phase siliconization densification and surface treatment of a recrystallized SiC sintered body for semiconductor use comprises the following steps:

[0042] (1) Using high-purity silicon carbide powder (purity ≥99.99wt%) as raw material, a recrystallization sintering technology was used to prepare a silicon carbide with a bulk density of 2.35g / cm3 in an Ar atmosphere at 2350℃ and a pressure of 128000Pa. 3 SiC sintered body;

[0043] (2) The recrystallized SiC sintered body was densified by immersion liquid phase siliconization in an Ar atmosphere at 1550°C and a pressure of 220000 Pa;

[0044] (3) The surface of the recrystallized SiC sintered body after siliconization was machined using a machining wheel to reduce the surface roughness to Ra0.408μm;

[0045] (4) Using a 17% HF acid aqueous solution to remove oxides on the surface of the recrystallized sintered body, blow dry and set aside;

[0046] (5) Using methyltrichlorosilane as raw material, the deposition temperature is 1300 ° C, the pressure is 5000 Pa, and a SiC protective coating with a thickness of about 110 μm is deposited on the recrystallized SiC sintered body. After the deposition is completed, the furnace is cooled.

[0047] Although, this embodiment adopts recrystallization sintering technology to prepare the bulk density of 2.35g / cm 3 The SiC sintered body is slightly smaller than that of Example 1 and has a body density of 2.64 g / cm 3 However, the surface of the recrystallized SiC sintered body treated with liquid-phase siliconization densification technology in this example is significantly denser, with almost no pores. Furthermore, after surface machining and pickling, the surface of the sintered body is even smoother and almost free of oxide scale. Therefore, the surface of the SiC protective coating deposited on the recrystallized SiC sintered body is relatively smooth.

[0048] like Figure 1 As shown in the figure, a 2.64 g / cm3 sintered product with a bulk density of 2.64 g / cm3 was prepared by recrystallization sintering technology in Ar atmosphere, 2400 °C and 125000 Pa pressure. 3 The XRD pattern of SiC sintered body is given by Figure 1 It can be seen that the diffraction peaks appearing in the figure are all diffraction peaks of α-SiC (including 2H-SiC, 4H-SiC, and 6H-SiC).

[0049] like Figure 2As shown in the figure, a 2.64 g / cm3 sintered product with a bulk density of 2.64 g / cm3 was prepared by recrystallization sintering technology in Ar atmosphere, 2400 °C and 125000 Pa pressure. 3 The surface morphology of the SiC sintered body is shown in Figure 2. Figure 2 It can be seen that the bulk density is 2.64 g / cm 3 There are many pores in the SiC sintered body and the surface roughness is very large.

[0050] like Figure 3 As shown in Figure 2, the XRD patterns of the recrystallized SiC sintered body after densification treatment by immersion liquid phase siliconization in Ar atmosphere, 1550℃, and 220000Pa pressure and surface machining method are shown in Figure 2. Figure 3 It can be seen that the diffraction peaks in the figure are the diffraction peaks of α-SiC and Si.

[0051] like Figure 4 As shown in the figure, the surface morphology of the recrystallized SiC sintered body after densification treatment by immersion liquid phase siliconization in Ar atmosphere, 1550℃ and 220000Pa pressure and surface machining method is shown in the figure. Figure 4 It can be seen that the density of the recrystallized SiC sintered body after treatment is greatly improved, there are almost no holes on the surface, and the surface roughness is greatly reduced.

[0052] like Figure 5 As shown in the figure, the surface morphology of the recrystallized sintered body after the oxide on the surface is removed by using a 17% HF acid aqueous solution. Figure 5 It can be seen that the surface roughness of the recrystallized SiC sintered body after surface pickling is further reduced, and there are almost no impurities on the surface.

[0053] like Figure 6 As shown in Figure 2, the XRD pattern of a SiC protective coating with a thickness of about 110 μm was deposited on a recrystallized SiC sintered body using methyltrichlorosilane as the raw material, at a deposition temperature of 1300°C and a pressure of 5000 Pa. Figure 6 It can be seen that the diffraction peak in the figure is only the diffraction peak of SiC.

[0054] like Figure 7 As shown in the figure, the cross-sectional morphology of the SiC protective coating with a thickness of about 110 μm was deposited on the recrystallized SiC sintered body using methyltrichlorosilane as the raw material, the deposition temperature was 1300 ° C, and the pressure was 5000 Pa. Figure 7 It can be seen that the SiC protective coating has a dense structure, almost no defects such as holes and cracks, and is well bonded to the recrystallized SiC sintered body. The coating thickness is about 110 μm.

[0055] The results of the embodiments show that the recrystallized SiC sintered parts prepared by the present invention after liquid phase siliconization densification technology treatment, surface treatment, and surface protective coating treatment have the advantages of low surface roughness, high density, high corrosion resistance, and high mechanical properties.

Claims

1. A method for liquid phase siliconization densification and surface treatment of a recrystallized SiC sintered body for semiconductor use, characterized in that: High-purity silicon carbide powder was used as raw material and SiC sintered body was prepared by recrystallization sintering technology. Liquid phase siliconization densification, surface machining and HF acid aqueous solution were used to remove surface oxide scale. The recrystallized SiC sintered body was further treated. Finally, SiC composite coating was prepared on the recrystallized SiC sintered body by chemical vapor deposition using methyltrichlorosilane as raw material.

2. The method for liquid phase siliconization densification and surface treatment of a recrystallized SiC sintered body for semiconductor use according to claim 1, characterized in that: The following steps are involved: (1) Using high-purity silicon carbide powder as raw material, using recrystallization sintering technology, in Ar atmosphere, sintering temperature of 2200-2500℃, 1-3 standard atmospheres of pressure to prepare silicon carbide with a density of 1.00g / cm 3 ~3.20g / cm 3 The bulk density of the recrystallized SiC sintered body is 2.00 g / cm 3 ~3.20g / cm 3 ; (2) densification of the recrystallized SiC sintered body by immersion liquid phase siliconizing in an Ar atmosphere at a liquid phase siliconizing temperature of 1450-1600°C and 1-3 standard atmospheres of pressure; (3) The surface of the recrystallized SiC sintered body after siliconization is machined using a machining wheel to reduce the surface roughness; (4) using an HF acid aqueous solution with a mass fraction of 3% to 30% to remove oxides on the surface of the recrystallized sintered body, and drying the body for later use; (5) Using methyltrichlorosilane as raw material, the deposition temperature is 1100-1350°C, the pressure is 1000-10000Pa, and a SiC protective coating with a thickness of 50 μm-1000 μm is deposited on the recrystallized SiC sintered body. After the deposition is completed, the furnace is cooled.

3. The method for liquid phase siliconization densification and surface treatment of a recrystallized SiC sintered body for semiconductor use according to claim 2, characterized in that: Preferably, in step (1), the sintering temperature is 2400° C. and the pressure is 125000 Pa.

4. The method for liquid phase siliconization densification and surface treatment of a recrystallized SiC sintered body for semiconductor use according to claim 2, wherein: Preferably, in step (2), the liquid phase siliconizing temperature is 1550° C. and the pressure is 220,000 Pa.

5. The method for liquid phase siliconization densification and surface treatment of a recrystallized SiC sintered body for semiconductor use according to claim 2, characterized in that: Preferably, in step (4), the mass fraction of the HF acid aqueous solution is 17%.

6. The method for liquid phase siliconization densification and surface treatment of a recrystallized SiC sintered body for semiconductor use according to claim 2, characterized in that: Preferably, in step (5), the deposition temperature is 1300° C. and the pressure is 5000 Pa.

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