Molybdenum-silicon target material and preparation method thereof

Abstract

The invention relates to the field of magnetron sputtering target materials, in particular to a molybdenum-silicon target material and a preparation method thereof. The preparation method comprises the steps that (1) high-purity Mo powder and high-purity Si powder are mixed and then subjected to vacuum heat treatment, and a molybdenum-silicon alloy blank is obtained; the atomic ratio of the high-purity Mo powder to the high-purity Si powder is 9: 3-5: 3, and the temperature of vacuum heat treatment is less than or equal to 1100 DEG C; (2) the molybdenum-silicon alloy blank is crushed and pulverized, and molybdenum-silicon alloy powder is obtained; (3) the molybdenum-silicon alloy powder, high-purity SiC powder and Si powder are mixed, and mixed powder is obtained; and 4) carrying out isostatic pressing treatment and reducing atmosphere sintering on the mixed powder. By means of the method, the oxygen content of an alloy system can be effectively reduced, the purity, compactness, microstructure uniformity and other performance of the molybdenum-silicon target material are improved, second phase distribution and target material sputtering coating quality are optimized, and the molybdenum-silicon target material with the excellent performance of being high in purity, low in oxygen, high in compactness, uniform in component structure and the like is obtained.

Description

Technical Field

[0001] This invention relates to the field of magnetron sputtering targets, and more particularly to a molybdenum-silicon target and its preparation method. Background Technology

[0002] Photolithography is the most complex, critical, time-consuming, and costly process in semiconductor chip manufacturing. The photolithography process uses a photomask as a template, which is then scaled down and projected onto the wafer using photolithography equipment. Therefore, the sophistication of photolithography directly affects the chip's manufacturing process and performance, making it a crucial foundation for the manufacturing process. With the increasing integration of semiconductor integrated circuits, photomask circuit diagrams are also trending towards higher precision and resolution. Phase-shifting masks utilize the intensity and phase of light to create images, offering even higher resolution and are widely used in advanced chip manufacturing processes below 28nm. Phase-shifting masks are created by depositing a Mo-Si thin film on a quartz substrate, causing a 180° phase difference in light as it passes through the film region, enhancing image contrast and improving image resolution.

[0003] To further optimize the performance of phase-shifted films, enhance their corrosion resistance, mechanical strength, and stability, and improve their light transmittance and conductivity, carbon (C) can be introduced into the phase-shifted film (MoSi metal film). Current C-introduction techniques primarily involve introducing gases such as CH4, CO, or CO2 as carbon sources during sputtering to form metal compound films such as MoSiONC, MoSiC, or MoSiOC. However, the introduction of these gases increases the partial pressure of the negative ion gas within the sputtering chamber, leading to a decrease in film deposition rate and flatness. This results in poor quality carbon-containing MoSi films and poses safety hazards.

[0004] CN 117105672 A describes a process of uniformly mixing molybdenum powder and silicon powder, followed by hot pressing and sintering to prepare a molybdenum-silicon target. However, the significant differences in physical properties between molybdenum powder and silicon powder make it difficult to ensure the uniformity of the target composition. CN 104513953 A describes a process of wet mixing molybdenum powder and silicon powder, followed by hot pressing to obtain a molybdenum-silicon target. However, the complex steps and residual solvents can easily introduce other impurities, affecting the purity of the target. CN117024124 A describes a process of ball milling to obtain a mixture of silicon powder and dimolybdenum diphosphate powder to ensure uniform powder mixing, followed by hot pressing and sintering to prepare a dense molybdenum-silicon target. However, prolonged ball milling can easily introduce impurities, potentially leading to powder agglomeration and deformation, thus reducing powder flowability and affecting the purity and density of the target. CN 119061361 A prepares carbon-containing MoSi targets by adding pure carbon powders such as carbon powder and diamond powder to powdered raw materials. CN 119061362 A prepares carbon-containing MoSi targets by introducing carbon-containing gas during high-temperature sintering, but it is difficult to guarantee the purity and compositional uniformity of the targets during mass production. Currently, there is an urgent need in this field for a novel method for preparing high-purity, low-oxygen molybdenum-silicon targets. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a molybdenum-silicon sputtering target and its preparation method. The method of this invention effectively solves the problems of high oxygen content, uneven microstructure and phase composition in existing molybdenum-silicon alloy sputtering targets used in phase-shifting mask substrates. It effectively reduces the oxygen content of the alloy system, improves the purity, density, and microstructure uniformity of the molybdenum-silicon sputtering target, optimizes the second-phase distribution and the film quality of the sputtered coating, and yields a molybdenum-silicon sputtering target with excellent properties such as high purity, low oxygen content, high density, and uniform composition and microstructure.

[0006] In a first aspect, the present invention provides a method for preparing a molybdenum-silicon target, comprising: 1) High-purity Mo powder and high-purity Si powder are mixed and then subjected to vacuum heat treatment to obtain molybdenum-silicon alloy billet.

[0007] The atomic ratio of the high-purity Mo powder to the high-purity Si powder is 9:3 to 5:3, and the vacuum heat treatment temperature is ≤1100℃.

[0008] 2) The molybdenum-silicon alloy billet is crushed and powdered to obtain molybdenum-silicon alloy powder.

[0009] 3) Mix the molybdenum-silicon alloy powder, high-purity SiC powder, and Si powder to obtain a mixed powder.

[0010] 4) The mixed powder is subjected to isostatic pressing and reducing atmosphere sintering.

[0011] This invention utilizes low-temperature vacuum heat treatment of high-purity powder with a specific Mo / Si atomic ratio to effectively reduce the oxygen content of the alloy system, producing a low-alloyed molybdenum-silicon billet. Fine-particle-size, high-quality molybdenum-silicon alloy powder is easily obtained through crushing and powdering. This alloy powder, when mixed with high-purity SiC and Si powders, effectively enhances sintering activity and densifies the sinter. The method also avoids the introduction of impurities and the influence of a large second phase on the microstructure. Furthermore, the introduction of SiC powder optimizes the sputtering performance of the target material and improves film quality. After isostatic pressing and sintering in a reducing atmosphere, stable MoC and MoSi2 phases are generated within the system. The unreacted Si phase acts as a binder, further increasing the sintering density. The reducing atmosphere further removes oxygen impurities, resulting in a high-purity, low-oxygen, high-density molybdenum-silicon target material with excellent composition and microstructure uniformity, better meeting the requirements of high-performance sputtering coatings.

[0012] Preferably, in step 1), the high-purity Mo powder has a purity ≥4N and a particle size of 3~10μm, for example, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc.; the high-purity Si powder has a purity ≥5N and a particle size of 10~20μm. Preferably, in step 1), the molybdenum-silicon alloy billet is Mo3Si, Mo5Si3, or Mo3Si / Mo5Si3. The particle size distribution and high purity of Mo and Si powder used in this invention help reduce impurities and improve the uniformity of powder mixing.

[0013] Preferably, in step 1), the temperature of the vacuum heat treatment is 900~1100℃, for example, 900℃, 920℃, 950℃, 980℃, 1000℃, etc. Preferably, the time of the vacuum heat treatment is 30~120min, for example, 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min, etc., with a vacuum degree ≤1Pa. The preferred low-temperature vacuum heat treatment conditions can better prepare low-alloy alloy billets such as Mo3Si, Mo5Si3, or Mo3Si / Mo5Si3, providing high-quality billets for subsequent fine powder preparation.

[0014] Preferably, in step 2), the particle size of the molybdenum-silicon alloy powder is ≤20μm, for example, 5μm, 8μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, etc. Preferably, the crushing and grinding includes ball milling, jaw crushing, or cone crushing.

[0015] Preferably, in step 3), the high-purity SiC powder has a purity ≥4N and a particle size of 0.01~1μm; the Si powder has a purity ≥5N and a particle size of 10~20μm.

[0016] Preferably, in step 3), the mixed powder comprises 30-70 wt.% molybdenum-silicon alloy powder, 30-70 wt.% high-purity Si powder, and 0.05-0.5 wt.% high-purity SiC powder. In this invention, the powder is mixed according to the molybdenum-silicon alloy powder ratio and product composition requirements. The preferred ratio yields better results.

[0017] In a preferred embodiment of the present invention, the key tools and auxiliary materials that come into direct contact with the powder, such as mixing jars, heat treatment crucibles, and ball mill jars, are made of high-purity molybdenum with a purity ≥3N5.

[0018] Preferably, in step 4), the isostatic pressing is cold isostatic pressing; preferably, the pressing force of the isostatic pressing is 80~240MPa, for example 80MPa, 85MPa, 90MPa, 100MPa, 120MPa, 130MPa, 140MPa, 150MPa, 170MPa, 190MPa, 200MPa, 240MPa, etc., preferably 120~240MPa, the isostatic pressing time is 30~60min, preferably 40~60min, and the density of the pressed billet is ≥75%. Using the preferred cold isostatic pressing and parameters yields better results.

[0019] Further preferably, in step 4), the reducing atmosphere sintering is hydrogen atmosphere sintering; preferably, the sintering temperature is 1100~1300℃, for example, 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, etc., preferably 1150~1200℃; the sintering time is 2~4h, for example, 2h, 2.5h, 3h, 3.5h, 4h, etc., preferably 3~3.5h; the hydrogen flow rate is 5~10L / min, for example, 5L / min, 6L / min, 7L / min, 8L / min, 9L / min, 10L / min, etc., preferably 5~8L / min. These preferred sintering conditions effectively remove residual oxygen, further optimize phase distribution, improve microstructure uniformity, and prevent abnormal grain growth.

[0020] Secondly, the present invention provides a molybdenum-silicon target material, which is obtained by the above-mentioned method for preparing molybdenum-silicon target materials.

[0021] Preferably, in the molybdenum-silicon target, the C content is 0.1~1 at.%, the Mo content is 10~20 at.%, and the balance is Si; the phase composition of the molybdenum-silicon target is MoSi2 phase, Si phase and MoC phase; the purity of the molybdenum-silicon target is ≥4N, the O content is ≤400ppm; the second phase size is ≤30μm, and the phase structure is free from segregation; the relative density is ≥99%, the internal porosity is ≤1μm, and the microhardness is ≥900HV. More preferably, the purity is ≥4N, the O content is ≤380ppm; the second phase size is ≤28μm, the phase structure is free from segregation, the relative density is ≥99.4%, the internal porosity is ≤0.5μm, and the microhardness is ≥905HV.

[0022] In this invention, the term "second phase" refers to the MoSi2 phase, the Si phase, and the MoC phase.

[0023] The beneficial effects of this invention are at least as follows: First, high-purity Mo powder and high-purity Si powder are mixed in a Mo-Si atomic ratio of 9:3 to 5:3. Then, a blank with a low degree of alloying, such as Mo3Si, Mo5Si3, or Mo3Si / Mo5Si3, is prepared by vacuum heat treatment at a relatively low temperature. Vacuum heat treatment reduces the O content and facilitates subsequent crushing and ball milling to prepare finer-particle-size, higher-quality alloy powder. Then, according to the composition requirements of the target material, the alloy powder, high-purity Si powder, and SiC powder are weighted and uniformly mixed. The finer SiC powder greatly improves sintering activity, allowing for the acquisition of a highly dense target material at a suitable sintering temperature, thus preventing the growth of the second phase from affecting the uniformity of the microstructure. Key tools and auxiliary materials that come into direct contact with the powder during the process are all made of high-purity molybdenum, effectively ensuring the purity of the powder. Furthermore, the introduction of a carbon source into the system through SiC powder effectively solves problems such as poor film quality, high production costs, and safety hazards associated with sputtering coating of target materials. Finally, the mixed powder is loaded into a mold and subjected to cold isostatic pressing and hydrogen atmosphere sintering in sequence. The small amount of SiC powder in the mixed powder decomposes easily under high-temperature conditions, and the free C combines with the metal to form the MoC phase. The low-alloyed Mo-Si phase further reacts with excess Si to generate the stable MoSi2 phase, while the unreacted Si phase acts as a solid-state sintering binder, improving the density of the sintered material. On the other hand, hydrogen atmosphere sintering can further reduce the O content in the alloy system, producing high-purity, low-oxygen, high-density, and uniformly structured molybdenum-silicon targets. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the molybdenum-silicon target preparation process provided in an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0027] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0028] Unless otherwise specified, the techniques or conditions described in the literature of this invention shall apply, or the product instructions shall be followed. Devices, instruments, reagents, etc., whose manufacturers are not specified, are all conventional products that can be purchased from legitimate channels. All experimental reagents and raw materials involved are commercially available, and all reagents are analytical grade products.

[0029] In some embodiments of the present invention, a method for preparing a high-purity, low-oxygen molybdenum silicon target material is provided, such as... Figure 1 As shown, the process includes: first, mixing high-purity Mo powder and high-purity Si powder in an atomic ratio of 9:3 to 5:3, and preparing Mo3Si, Mo5Si3, or Mo3Si / Mo5Si3 alloy billets through low-temperature vacuum heat treatment at temperatures below 1100℃; next, mechanically crushing the alloy billets in a device made of high-purity molybdenum to obtain alloy powder with a small particle size; then, weighing and uniformly mixing the alloy powder, high-purity Si powder, and high-purity SiC powder according to product requirements, wherein the mixed powder contains 30-70 wt.% molybdenum-silicon alloy powder, 30-70 wt.% Si powder, and 0.05-0.5 wt.% SiC powder; finally, loading the mixed powder into a mold and sequentially performing cold isostatic pressing and hydrogen atmosphere sintering to obtain high-purity low-oxygen molybdenum-silicon target material. In the preferred embodiment of the present invention, the alloy system has a C content of 0.1~1 at.%, a Mo content of 10~20 at.%, and the balance being Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The purity is ≥4N, the O content is ≤400ppm, the second phase size is ≤30μm, and the microstructure has no phase segregation. The relative density is ≥99%, the internal porosity is ≤1μm, and the microhardness is ≥900HV.

[0030] Example 1 This embodiment provides a molybdenum-silicon sputtering target and its preparation method, including: Mo3Si alloy billet was prepared by mixing 4N grade Mo powder (5 μm particle size) and 5N grade Si powder (20 μm particle size) at an atomic ratio of 9:3 and then performing low-temperature vacuum heat treatment at 1000℃ for 60 min under a vacuum of 0.1 Pa. The alloy billet was then ball-milled in a high-purity molybdenum (3N5) ​​container to obtain molybdenum-silicon alloy powder with a particle size of 15 μm. Alloy powder, 5N-grade Si powder with a particle size of 20 μm, and 4N-grade SiC powder with a particle size of 0.1 μm were uniformly mixed. The mixed powder contained 34.47 wt.% molybdenum-silicon alloy powder, 65.46 wt.% Si powder, and 0.07 wt.% SiC powder. The mixed powder was loaded into a mold and subjected to cold isostatic pressing at a pressure of 120 MPa for 60 min, resulting in a blank density of 80%. Finally, the blank was sintered in a hydrogen atmosphere at a temperature of 1200℃ for 3 h at a hydrogen flow rate of 8 L / min to prepare a high-purity, low-oxygen molybdenum-silicon target. In the molybdenum-silicon target alloy system provided in this embodiment, the C content is 0.1 at.%, the Mo content is 10 at.%, and the balance is Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The target purity is 4N, the O content is 360ppm, the maximum second phase size is 26μm, the microstructure has no phase segregation, the relative density is 99.5%, the maximum internal porosity is 0.1μm, and the microhardness is 913HV.

[0031] Example 2 This embodiment provides a molybdenum-silicon sputtering target and its preparation method, including: Mo5Si3 alloy billet was prepared by mixing 5N grade Mo powder (10 μm particle size) and 6N grade Si powder (10 μm particle size) at an atomic ratio of 5:3 and then subjected to low-temperature vacuum heat treatment at 1000℃ for 60 min under a vacuum of 0.1 Pa. The alloy billet was then crushed and pulverized in a high-purity molybdenum cone crusher (3N5 purity) to obtain molybdenum-silicon alloy powder with a particle size of 15 μm. Alloy powder, 6N-grade Si powder with a particle size of 10 μm, and 5N-grade SiC powder with a particle size of 0.01 μm were uniformly mixed. The mixed powder contained 62.05 wt.% molybdenum-silicon alloy powder, 37.45 wt.% Si powder, and 0.05 wt.% SiC powder. The mixed powder was loaded into a mold and subjected to cold isostatic pressing at a pressure of 180 MPa for 30 min, resulting in a billet density of 83%. Finally, the billet was sintered in a hydrogen atmosphere at a temperature of 1200℃ for 2 h at a hydrogen flow rate of 5 L / min to prepare a high-purity, low-oxygen molybdenum-silicon target. In the molybdenum-silicon target alloy system provided in this embodiment, the C content is 0.1 at.%, the Mo content is 20 at.%, and the balance is Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The target purity is 5N, the O content is 380ppm, the maximum second phase size is 28μm, the microstructure has no phase segregation, the relative density is 99.6%, the maximum internal porosity is 0.1μm, and the microhardness is 908HV.

[0032] Example 3 This embodiment provides a molybdenum-silicon sputtering target and its preparation method, including: Mo3Si / Mo5Si3 alloy billets were prepared by mixing 4N-grade Mo powder (5 μm particle size) and 6N-grade Si powder (20 μm particle size) at an atomic ratio of 7:3 and then subjected to low-temperature vacuum heat treatment at 1000℃ for 60 min under a vacuum of 0.1 Pa. The alloy billets were then ball-milled in a high-purity molybdenum (3N5) ​​container to obtain molybdenum-silicon alloy powder with a particle size of 15 μm. Alloy powder, 6N-grade Si powder with a particle size of 20 μm, and 5N-grade SiC powder with a particle size of 0.1 μm were uniformly mixed. The mixed powder contained 37.43 wt.% molybdenum-silicon alloy powder, 62.51 wt.% Si powder, and 0.06 wt.% SiC powder. The mixed powder was loaded into a mold and subjected to cold isostatic pressing at a pressure of 120 MPa for 60 min, resulting in a blank density of 80%. Finally, the blank was sintered in a hydrogen atmosphere at a temperature of 1200℃ for 3 h at a hydrogen flow rate of 8 L / min to prepare a high-purity, low-oxygen molybdenum-silicon target. In the molybdenum-silicon target alloy system provided in this embodiment, the C content is 0.1 at.%, the Mo content is 10 at.%, and the balance is Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The target purity is 5N, the O content is 240ppm, the maximum second phase size is 23μm, the microstructure has no phase segregation, the relative density is 99.6%, the maximum internal porosity is 0.1μm, and the microhardness is 923HV.

[0033] Example 4 This embodiment provides a molybdenum-silicon sputtering target and its preparation method, including: Mo3Si alloy billet was prepared by mixing 4N grade Mo powder (5 μm particle size) and 5N grade Si powder (20 μm particle size) at an atomic ratio of 9:3 and then performing low-temperature vacuum heat treatment at 900℃ for 120 min under a vacuum of 0.1 Pa. The alloy billet was then ball-milled in a high-purity molybdenum (3N5) ​​container to obtain molybdenum-silicon alloy powder with a particle size of 15 μm. Alloy powder, 5N-grade Si powder with a particle size of 20 μm, and 4N-grade SiC powder with a particle size of 0.1 μm were uniformly mixed. The mixed powder contained 34.47 wt.% molybdenum-silicon alloy powder, 65.46 wt.% Si powder, and 0.07 wt.% SiC powder. The mixed powder was loaded into a mold and subjected to cold isostatic pressing at a pressure of 120 MPa for 60 min, resulting in a blank density of 80%. Finally, the blank was sintered in a hydrogen atmosphere at a temperature of 1200℃ for 3 h at a hydrogen flow rate of 8 L / min to prepare a high-purity, low-oxygen molybdenum-silicon target. In the molybdenum-silicon target alloy system provided in this embodiment, the C content is 0.1 at.%, the Mo content is 10 at.%, and the balance is Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The target purity is 4N, the O content is ≤365ppm, the maximum second phase size is 23μm, the microstructure has no phase segregation, the relative density is 99.5%, the maximum internal porosity is 0.1μm, and the microhardness is 915HV.

[0034] Example 5 This embodiment provides a molybdenum-silicon sputtering target and its preparation method, including: Mo3Si alloy billet was prepared by mixing 4N grade Mo powder (5 μm particle size) and 6N grade Si powder (20 μm particle size) at an atomic ratio of 9:3 and then performing low-temperature vacuum heat treatment at 900℃ for 120 min under a vacuum of 0.1 Pa. The alloy billet was then ball-milled in a high-purity molybdenum (3N5) ​​container to obtain molybdenum-silicon alloy powder with a particle size of 15 μm. Alloy powder, 6N-grade Si powder with a particle size of 20 μm, and 5N-grade SiC powder with a particle size of 0.1 μm were uniformly mixed. The mixed powder contained 34.47 wt.% molybdenum-silicon alloy powder, 65.46 wt.% Si powder, and 0.07 wt.% SiC powder. The mixed powder was loaded into a mold and subjected to cold isostatic pressing at a pressure of 240 MPa for 30 min, resulting in a billet density of 80%. Finally, the billet was sintered in a hydrogen atmosphere at a temperature of 1100℃ for 4 h at a hydrogen flow rate of 5 L / min to prepare a high-purity, low-oxygen molybdenum-silicon target. In the molybdenum-silicon target alloy system provided in this embodiment, the C content is 0.1 at.%, the Mo content is 10 at.%, and the balance is Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The target purity is 5N, the O content is 380ppm, the maximum second phase size is 25μm, the microstructure has no phase segregation, the relative density is 99.4%, the maximum internal porosity is 0.1μm, and the microhardness is 906HV.

[0035] Example 6 This embodiment provides a molybdenum-silicon sputtering target and its preparation method, including: Mo5Si3 alloy billet was prepared by mixing 4N grade Mo powder (10 μm particle size) and 6N grade Si powder (10 μm particle size) at an atomic ratio of 5:3 and then subjected to low-temperature vacuum heat treatment at 1000℃ for 60 min under a vacuum of 0.1 Pa. The alloy billet was then crushed and pulverized in a high-purity molybdenum cone crusher (3N5 purity) to obtain molybdenum-silicon alloy powder with a particle size of 15 μm. Alloy powder, 6N-grade Si powder with a particle size of 10 μm, and 5N-grade SiC powder with a particle size of 0.01 μm were uniformly mixed. The mixed powder contained 62.05 wt.% molybdenum-silicon alloy powder, 37.45 wt.% Si powder, and 0.5 wt.% SiC powder. The mixed powder was loaded into a mold and subjected to cold isostatic pressing at a pressure of 180 MPa for 30 min, resulting in a billet density of 83%. Finally, the billet was sintered in a hydrogen atmosphere at a temperature of 1200℃ for 2 h at a hydrogen flow rate of 10 L / min to prepare a high-purity, low-oxygen molybdenum-silicon target. In the molybdenum-silicon target alloy system provided in this embodiment, the C content is 0.1 at.%, the Mo content is 10 at.%, and the balance is Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The target purity is 5N, the O content is 340ppm, the maximum second phase size is 28μm, the microstructure has no phase segregation, the relative density is 99.6%, the maximum internal porosity is 0.1μm, and the microhardness is 923HV.

[0036] Comparative Example 1 MoSi alloy billets were prepared by mixing 4N-grade Mo powder (5 μm particle size) and 6N-grade Si powder (20 μm particle size) at an atomic ratio of 1:9 and then subjected to low-temperature vacuum heat treatment at 1300℃ for 120 min under a vacuum of 0.1 Pa. The alloy billets were then ball-milled in a high-purity molybdenum (3N5) ​​container, resulting in a high degree of alloying and an alloy particle size of 50 μm. The alloy powder was then loaded into a mold and subjected to cold isostatic pressing at a pressure of 180 MPa for 40 min, yielding a billet density of 75%. Finally, the billets were sintered in a hydrogen atmosphere at 1200℃ for 3 h at a hydrogen flow rate of 10 L / min to prepare high-purity, low-oxygen molybdenum-silicon sputtering targets. In this comparative example, the molybdenum-silicon target alloy system has a Mo content of 10 at.%, with the balance being Si. The phase composition consists of MoSi2 phase and Si phase. The target purity is 4N, the O content is 1000ppm, and there are coarse second phases with a size of 50μm that are unevenly distributed. The relative density is 99.2%, but 3μm pores can be observed at the interface between the two phases. The microhardness is 903HV.

[0037] Comparative Example 2 Molybdenum-silicon alloy billets were prepared by mixing 4N-grade Mo powder (5 μm particle size) and 6N-grade Si powder (20 μm particle size) at an atomic ratio of 12:3 and then subjected to low-temperature vacuum heat treatment at 1000℃ for 60 min under a vacuum of 0.1 Pa. The alloy billets were then ball-milled in a high-purity molybdenum (3N5) ​​container to obtain molybdenum-silicon alloy powder with a particle size of 28 μm. Alloy powder, 6N-grade Si powder with a particle size of 20 μm, and 5N-grade SiC powder with a particle size of 0.1 μm were uniformly mixed. The mixed powder contained 28.26 wt.% molybdenum-silicon alloy powder, 71.67 wt.% Si powder, and 0.07 wt.% SiC powder. The mixed powder was loaded into a mold and subjected to cold isostatic pressing at a pressure of 120 MPa for 60 min, resulting in a blank density of 80%. Finally, the blank was sintered in a hydrogen atmosphere at a temperature of 1200℃ for 3 h at a hydrogen flow rate of 8 L / min to prepare a high-purity, low-oxygen molybdenum-silicon target. In the molybdenum-silicon sputtering alloy system provided in this comparative example, the C content is 0.1 at.%, the Mo content is 10 at.%, and the balance is Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The sputtering purity is 4N, the O content is 380ppm, there are coarse second phases with a size of 36μm and uneven distribution, the relative density is 99.2%, the maximum internal porosity is 0.5μm, and the microhardness is 905HV.

[0038] Comparative Example 3 Mo5Si3 alloy billet was prepared by mixing 4N grade Mo powder (10 μm particle size) and 6N grade Si powder (10 μm particle size) at an atomic ratio of 5:3 and then subjected to low-temperature vacuum heat treatment at 1250℃ for 120 min under a vacuum of 0.1 Pa. The alloy billet was then crushed and pulverized in a high-purity molybdenum cone crusher (3N5 purity) to obtain molybdenum-silicon alloy powder with a particle size of 30 μm. Alloy powder, 6N-grade Si powder with a particle size of 10 μm, and 5N-grade SiC powder with a particle size of 0.01 μm were uniformly mixed. The mixed powder contained 62.05 wt.% molybdenum-silicon alloy powder, 37.45 wt.% Si powder, and 0.05 wt.% SiC powder. The mixed powder was loaded into a mold and subjected to cold isostatic pressing at a pressure of 180 MPa for 30 min, resulting in a billet density of 83%. Finally, the billet was sintered in a hydrogen atmosphere at a temperature of 1200℃ for 2 h at a hydrogen flow rate of 5 L / min to prepare a high-purity, low-oxygen molybdenum-silicon target. In the molybdenum-silicon sputtering alloy system provided in this comparative example, the C content is 0.1 at.%, the Mo content is 20 at.%, and the balance is Si. The phase composition is MoSi2 phase, Si phase and a small amount of MoC phase. The sputtering purity is 4N, the O content is 375ppm, there are coarse second phases with a size of 43μm and uneven distribution, the relative density is 99.1%, the maximum internal porosity is 0.5μm, and the microhardness is 908HV.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a molybdenum-silicon target, characterized in that, include: 1) High-purity Mo powder and high-purity Si powder are mixed and then subjected to vacuum heat treatment to obtain molybdenum-silicon alloy billet; The atomic ratio of the high-purity Mo powder to the high-purity Si powder is 9:3 to 5:3, and the vacuum heat treatment temperature is ≤1100℃. 2) The molybdenum-silicon alloy billet is crushed and powdered to obtain molybdenum-silicon alloy powder; 3) The molybdenum-silicon alloy powder, high-purity SiC powder, and Si powder are mixed to obtain a mixed powder; 4) The mixed powder is subjected to isostatic pressing and reducing atmosphere sintering.

2. The preparation method according to claim 1, characterized in that, In step 1), the purity of the high-purity Mo powder is ≥4N and the particle size is 3~10μm; the purity of the high-purity Si powder is ≥5N and the particle size is 10~20μm; and / or, in step 1), the molybdenum-silicon alloy billet is Mo3Si, Mo5Si3 or Mo3Si / Mo5Si3.

3. The preparation method according to claim 1 or 2, characterized in that, In step 1), the temperature of the vacuum heat treatment is 900~1100℃; preferably, the time of the vacuum heat treatment is 30~120min, and the vacuum degree is ≤1Pa.

4. The preparation method according to any one of claims 1 to 3, characterized in that, In step 2), the particle size of the molybdenum-silicon alloy powder is ≤20μm, and / or the crushing and powdering includes ball milling, jaw crushing or cone crushing.

5. The preparation method according to any one of claims 1 to 4, characterized in that, In step 3), the purity of the high-purity SiC powder is ≥4N and the particle size is 0.01~1μm; the purity of the Si powder is ≥5N and the particle size is 10~20μm.

6. The preparation method according to any one of claims 1 to 5, characterized in that, In step 3), the mixed powder contains 30-70 wt.% molybdenum-silicon alloy powder, 30-70 wt.% high-purity Si powder, and 0.05-0.5 wt.% high-purity SiC powder.

7. The preparation method according to any one of claims 1 to 6, characterized in that, In step 4), the static pressing is cold isostatic pressing; preferably, the pressing force of the isostatic pressing is 80~240MPa, the isostatic pressing time is 30~60min, and the density of the pressed billet is ≥75%.

8. The preparation method according to any one of claims 1 to 7, characterized in that, In step 4), the reducing atmosphere sintering is hydrogen atmosphere sintering; preferably, the sintering temperature is 1100~1300℃, the sintering time is 2~4h, and the hydrogen flow rate is 5~10L / min.

9. A molybdenum-silicon sputtering target, characterized in that, It is obtained by the preparation method of the molybdenum-silicon target according to any one of claims 1 to 8.

10. The molybdenum-silicon sputtering target according to claim 9, characterized in that, In the molybdenum-silicon target, the C content is 0.1~1 at.%, the Mo content is 10~20 at.%, and the balance is Si; the phase composition of the molybdenum-silicon target is MoSi2 phase, Si phase and MoC phase; the purity of the molybdenum-silicon target is ≥4N, the O content is ≤400ppm; the second phase size is ≤30μm, and the microstructure has no phase segregation; Relative density ≥99%, internal porosity ≤1μm, microhardness ≥900HV.

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