A method for hot isostatic pressing of tungsten carbide products for the semiconductor field and use thereof

Abstract

The application belongs to the technical field of hard alloy material preparation for semiconductor industry, and relates to a hot isostatic pressing preparation method and application of a tungsten carbide product for the semiconductor field, comprising the following steps: firstly, adding cobalt powder and yttrium oxide powder with specific mass ratios to tungsten carbide powder to obtain mixed raw material powder, drying after mixing to prepare tungsten carbide composite powder; then, loading the tungsten carbide composite powder into a mold, using a staged cold pressing process to press and form, and performing vacuum degreasing sintering to prepare a tungsten carbide alloy base; finally, performing strengthening treatment on the tungsten carbide alloy base, cooling to room temperature, and finally obtaining a tungsten carbide finished alloy. The tungsten carbide finished alloy prepared by the application has the advantages of high density, ultra-fine grains, uniform structure and precisely controllable composition, and meets the use requirements of semiconductor hard alloy cutters and molds, and significantly improves the service life and use reliability of the product.

Description

Technical Field

[0001] This invention belongs to the field of hard alloy material preparation technology for the semiconductor industry, and relates to a hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field and its application. Background Technology

[0002] Tungsten carbide (WC), with its ultra-high hardness, excellent wear resistance, high temperature resistance, and low chemical reactivity, has become a core tooling material for precision semiconductor machining, widely used in critical processes such as PCB drilling, wafer dicing, chip packaging slot milling, and semiconductor ceramic component cutting. In the manufacturing of very large-scale integrated circuits (VLSI) and third-generation semiconductors, the uniform wear resistance and chemical corrosion resistance of the cutting tools directly determine the chip cutting yield, device dimensional consistency, and processing efficiency. Furthermore, due to its high compressive strength and wear resistance, tungsten carbide is also an ideal mold material in semiconductor device manufacturing, widely used in precision forming processes such as leadframe punching, microelectrode forming, and high-density wire bonding fixtures in chip packaging.

[0003] However, existing manufacturing processes for tungsten carbide cutting tools for semiconductors have significant compatibility defects, mainly in the following three aspects: (1) Insufficient density and resistance to cracking Traditional hot-pressed sintered tools have a relative density of only 96.8%~97.5%, and micropores are easily left on the cutting edge. During high-speed rotary cutting (the typical speed of semiconductor dicing tools is 10,000~30,000 rpm), the combined effect of mechanical stress and thermal stress can easily cause the cutting edge to break, resulting in a dicing slit width fluctuation deviation of more than 8% and a chip edge breakage rate of more than 5%.

[0004] (2) Poor wear resistance and corrosion resistance, resulting in limited service life. Conventional processes are not optimized for semiconductor processing environments. During the cutting process, the corrosive effects of deionized water and chemical additives, as well as the thermal stress generated by frictional temperature rise, all accelerate tool wear. In practical applications, tools need to be replaced after a continuous cutting distance of only 300~800 m, which significantly increases production costs.

[0005] (3) Insufficient control over microstructure and composition design Existing processes lack sufficient precision in controlling grain size (typically >3μm) and have high impurity content (especially oxygen and alkali metals, >50 ppm), resulting in poor overall uniformity of microstructure and properties. This not only reduces the wear resistance of the cutting edge but also easily leads to particle shedding during cutting, causing contamination of semiconductor devices. Furthermore, traditional cutting tools often use a single cobalt content formulation, failing to be customized according to the different hardness and toughness requirements of roughing and finishing, further limiting machining accuracy and efficiency.

[0006] Therefore, there is an urgent need to provide a hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and propose a hot isostatic pressing (HIP) method for preparing tungsten carbide products for the semiconductor field, as well as its applications. This method, through customized composition, precise process control, and ultra-pure process control, can produce tungsten carbide alloys with a relative density ≥99.9% and a grain size ≤1μm. Simultaneously, the amount of cobalt added can be flexibly adjusted within the range of 3wt% to 10wt% according to actual processing conditions, thereby achieving a balance between material hardness and toughness. The tungsten carbide alloy prepared by this invention possesses the advantages of high density, ultra-fine grains, uniform microstructure, and precise compositional control, effectively solving the pain points of existing products such as easy chipping of the cutting edge, rapid wear rate, and easy device contamination. It is suitable for the requirements of semiconductor cemented carbide tools and molds, significantly improving the service life and reliability of the products.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention discloses a hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field, comprising the following steps: Step 1: Add cobalt powder and yttrium oxide powder in a specific mass ratio to tungsten carbide powder to obtain a mixed raw material powder, wherein the mass ratio of the cobalt powder is compatible with the finished tungsten carbide alloy; add grinding media to the mixed raw material powder, mix and then dry to obtain tungsten carbide composite powder; Step 2: The tungsten carbide composite powder is loaded into a mold and pressed into shape using a staged cold pressing process to obtain a cold-pressed green blank; the cold-pressed green blank is then subjected to vacuum debinding and sintering to obtain a tungsten carbide alloy matrix. Step 3: After strengthening the tungsten carbide alloy matrix, cool it to room temperature using a specific cooling rate to finally obtain the finished tungsten carbide alloy.

[0009] Specifically, in step one, the grinding medium is preferably anhydrous ethanol or deionized water.

[0010] Specifically, in step one, the mixing operation preferably adopts a ball milling process, and in the ball milling process, cemented carbide or zirconium oxide is preferably used as the grinding ball.

[0011] Specifically, in step one, the drying process preferably adopts spray drying. To avoid oxidation of the tungsten carbide composite powder and ensure the purity of the powder, the drying process is carried out in an inert protective atmosphere, and nitrogen or argon is preferred as the inert atmosphere.

[0012] Specifically, in step two, the mold is an elastomer mold, and the mold cavity is close to the contour of the tungsten carbide finished alloy.

[0013] Specifically, before filling the tungsten carbide composite powder, a release agent is applied to the inner wall of the mold, and a molding agent is added to the tungsten carbide composite powder at the same time.

[0014] More specifically, the release agent is preferably boron nitride, and the molding agent is preferably paraffin wax or polyethylene glycol.

[0015] More specifically, adding molding agents can improve the plasticity of tungsten carbide composite powder pressing, while release agents can prevent cold-pressed green blanks from sticking to the inner wall of the mold, making it easier for the cold-pressed green blanks to be completely demolded.

[0016] Further, in step one, the tungsten carbide accounts for 89.2~96.7 wt% of the mass of the mixed raw material powder, the cobalt powder accounts for 3~10 wt% of the mass of the mixed raw material powder, and the yttrium oxide powder accounts for 0.3~0.8 wt% of the mass of the mixed raw material powder.

[0017] Specifically, in this invention, the particle size of the tungsten carbide (WC) powder is controlled within the range of 0.5~5μm; the cobalt content is the main parameter for regulating the toughness of the finished tungsten carbide alloy, and the hardness and toughness of the finished tungsten carbide alloy can be adjusted by changing the particle size of the tungsten carbide powder—the smaller the particle size of the tungsten carbide powder, the higher the hardness and the lower the toughness of the finished tungsten carbide alloy; conversely, the larger the particle size of the tungsten carbide powder, the higher the toughness and the lower the hardness of the finished tungsten carbide alloy.

[0018] Specifically, the particle size of the yttrium oxide powder is preferably in the nanometer range. The yttrium oxide powder is preferably nano-sized powder. The nano-yttrium oxide can be uniformly dispersed in the interior of the alloy matrix. During the sintering process, it pins the grain boundaries, hinders the migration and abnormal growth of tungsten carbide grains, and thus optimizes the uniformity of the microstructure of the sintered product.

[0019] Furthermore, when the hardness of the finished tungsten carbide alloy is 1700~2100HV, the mass percentage of cobalt powder in the mixed raw material powder is 3~8wt%.

[0020] Specifically, when preparing precision machining tools such as PCB drilling bits and wafer dicing blades, or stretching dies and precision stamping die parts for high wear-resistant conditions, it is necessary to control the mass fraction of cobalt powder in the raw material powder to 3~8wt% to ensure the high hardness of the finished tungsten carbide alloy.

[0021] Furthermore, when the hardness of the finished tungsten carbide alloy is 1500~1800HV, the mass percentage of cobalt powder in the mixed raw material powder is 6~10wt%.

[0022] Specifically, when preparing roughing tools such as encapsulation slot milling cutters, as well as products such as drawing dies and stamping parts that require high toughness, it is necessary to control the mass fraction of cobalt powder in the raw material powder to 6~10wt% in order to improve the toughness of the finished tungsten carbide alloy.

[0023] Furthermore, in step two, the staged cold pressing process sequentially includes a low-pressure pressing stage and a high-pressure pressing stage; the pressure value of the low-pressure pressing stage is 12~17MPa, and the holding time is 8~12min; the pressure value of the high-pressure pressing stage is 20~25MPa, and the holding time is 30~50min.

[0024] Specifically, the pressure increase rate of the low-pressure pressing stage is preferably 5 MPa / min, and the pressure holding time is preferably 10 min; the pressure increase rate of the high-pressure pressing stage is preferably 6 MPa / min, and the pressure holding time is preferably 40 min.

[0025] Specifically, the low-pressure pressing stage can achieve the initial rearrangement and regularization of tungsten carbide composite powder particles, providing sufficient time for the gas inside the gaps to escape; the high-pressure pressing stage can completely remove the residual gas in the gaps of the powder, effectively improving the density and uniformity of the tungsten carbide pressed green compact.

[0026] Furthermore, in step two, the vacuum degree used in the vacuum degreasing and sintering process is 10. -3 ~10 -4 Pa.

[0027] Specifically, the vacuum degreasing sintering is carried out in a vacuum heat treatment furnace.

[0028] Furthermore, in step two, the vacuum degreasing and sintering process includes a degreasing stage and a sintering stage in sequence; the temperature of the degreasing stage is 900~1000℃, and the holding time is 30~50min; the temperature of the sintering stage is 1350~1500℃, and the holding time is 20~40min.

[0029] Specifically, the heating rate during the degreasing stage is preferably 5°C / min to preheat the cold-pressed green blank and eliminate temperature gradients. The heating rate during the sintering stage is preferably 10°C / min to promote initial particle bonding and increase density, while avoiding grain growth due to excessively high temperatures or prolonged holding times. Furthermore, the forming agent added during the molding process can be fully volatilized and removed during this stage.

[0030] Specifically, after vacuum degreasing and sintering is completed, the tungsten carbide alloy matrix is ​​cooled to room temperature in the furnace to eliminate or reduce defects caused by thermal stress.

[0031] Furthermore, in step three, the strengthening treatment adopts a hot isostatic pressing process with the following process parameters: temperature 1300~1450℃, pressure 120~160MPa, and heat and pressure holding time 2~4h.

[0032] Specifically, the strengthening treatment can eliminate residual pores inside the matrix and achieve complete densification of the tungsten carbide alloy matrix.

[0033] Specifically, after the strengthening treatment is completed, a specific cooling rate is used for controlled cooling, which is 6~16℃ / min. This cooling rate can avoid lattice distortion and alloy cracking caused by rapid cooling, and can also promote the transformation of a large amount of cobalt phase into a high-toughness face-centered cubic structure.

[0034] Secondly, this invention discloses the application of tungsten carbide finished alloy in tungsten carbide cutting tools and molds in the semiconductor field, and the tungsten carbide finished alloy is prepared by hot isostatic pressing of tungsten carbide products in the semiconductor field.

[0035] Specifically, it can be used in PCB drilling tools, wafer dicing tools, chip packaging milling tools, precision cutting tools for semiconductor components, as well as wire drawing dies and precision stamping dies.

[0036] Compared with the prior art, the present invention has the following beneficial effects: First, this invention provides a method for preparing tungsten carbide products for the semiconductor field. This method employs a synergistic process combining powder refining, cold pressing, vacuum debinding and sintering, and hot isostatic pressing, as detailed below: First, the particle size and dispersion uniformity of tungsten carbide composite powder are refined and optimized by ball milling to eliminate powder agglomeration defects. The impurity content in the powder, especially oxygen and alkali metal elements, is strictly controlled to keep them at a low level, laying the raw material foundation for the uniform density of cold-pressed green bodies.

[0037] Subsequently, a staged cold pressing process is used to press the tungsten carbide composite powder into shape. The staged cold pressing process includes a low-pressure pressing stage and a high-pressure pressing stage: in the low-pressure pressing stage, relying on powder refinement and a relatively low pressurization rate (5MPa / min), the powder is initially densified and rearranged into regular shapes; in the high-pressure pressing stage, the pressurization rate is increased to 6MPa / min, which promotes the full discharge of residual gas between the powder particles, ensuring the uniformity of the green body structure and the regularity of its shape, thereby ensuring that it is not prone to deformation and cracking during the subsequent vacuum debinding and sintering process.

[0038] Next, the prepared cold-pressed green body is placed in a vacuum heat treatment furnace for vacuum debinding and sintering. This process removes the forming agent from the inside of the cold-pressed green body and forms sintering necks between the particles, while achieving precise control over the grain size. This allows for the shaping and initial densification of the green body while inhibiting abnormal grain growth and maintaining a fine-grained structure. During sintering, an inert gas (such as argon) is introduced as a protective atmosphere to prevent oxidation or the introduction of impurities into the green body at high temperatures. As sintering progresses, a large number of interconnected pores are transformed into closed micropores, thus giving the green body reliable matrix strength sufficient to withstand the high temperature and pressure of the subsequent hot isostatic pressing process without collapsing.

[0039] Finally, the tungsten carbide alloy matrix is ​​strengthened using a hot isostatic pressing (HIP) process. This process, through omnidirectional pressure under high temperature and pressure, further closes the residual micropores inside the green body after refining the powder and obtaining a uniform green body in the early stage, thereby achieving near-complete densification of the matrix. Simultaneously, an inert gas (such as argon) is used as the pressure transmission medium during the HIP process, and the purity of the atmosphere is strictly controlled to avoid contamination of the matrix by impurities at high temperatures.

[0040] Secondly, on the one hand, this invention can match the cobalt powder content according to the required hardness of the finished product: when the required hardness of the tungsten carbide alloy is 1700~2100HV, the mass ratio of cobalt powder in the mixed raw material powder is set to 3~8wt%; when the working conditions require higher toughness and allow the hardness of the tungsten carbide alloy to drop to the range of 1500~1800HV, the mass ratio of cobalt powder in the mixed raw material powder is adjusted to 6~10wt%. This invention overcomes the technical defects of traditional cutting tools that use a single cobalt content formula and are difficult to take into account the different requirements of hardness and toughness for rough and fine machining of semiconductor tungsten carbide products through the formula design of matching cobalt content in different ranges.

[0041] On the other hand, the tungsten carbide alloy obtained by the method provided by this invention has isotropic characteristics, a uniform and fine microstructure, and high performance consistency. It also possesses excellent hardness, wear resistance, and impact resistance, with a hardness greater than 2000 HV, a bending strength greater than 2400 MPa, and a fracture toughness greater than 10. Furthermore, it can be adapted and adjusted according to the application needs of different scenarios, thereby effectively improving the service life and reliability of tungsten carbide cutting tools and molds. Attached Figure Description

[0042] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0045] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0046] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0047] Example 1 This embodiment provides a hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field, including the following steps: Step 1: Select tungsten carbide powder with an average particle size of 0.5 μm and a mass fraction of 89.2 wt% of the tungsten carbide powder. Add 10 wt% of cobalt powder and 0.8 wt% of nano-yttrium oxide powder to the tungsten carbide powder to obtain a mixed raw material powder.

[0048] The mixed raw material powder was placed in a ball mill, and anhydrous ethanol was added as the grinding medium. Hard alloy was used as the grinding balls for mixing. Then, it was spray-dried under the protective atmosphere of argon to obtain tungsten carbide composite powder.

[0049] Step 2: Select an elastomer mold with a cavity that closely resembles the finished tungsten carbide alloy, and coat its inner wall with boron nitride release agent; use paraffin wax as a molding agent, and load tungsten carbide composite powder with added paraffin wax into the mold.

[0050] Tungsten carbide composite powder is pressed into shape using a staged cold pressing process. The staged cold pressing process includes a low-pressure pressing stage and a high-pressure pressing stage. First, in the low-pressure pressing stage, the pressure is increased to 15MPa at a rate of 5MPa / min and held for 10min. Then, in the high-pressure pressing stage, the pressure is increased to 20MPa at a rate of 6MPa / min and held for 40min to obtain a cold-pressed green blank.

[0051] After the phased cold pressing process is completed, the cold-pressed green blank is placed in a vacuum heat treatment furnace and evacuated to a vacuum level of 3.2 × 10⁻⁶. -4Pa is used to perform vacuum debinding and sintering, which includes a debinding stage and a sintering stage. First, in the debinding stage, the temperature is raised to 1000℃ at a rate of 5℃ / min and held for 40min before entering the sintering stage. Then, the temperature is raised to 1500℃ at a rate of 10℃ / min and held for 30min to obtain a tungsten carbide alloy matrix.

[0052] Step 3: Transfer the tungsten carbide alloy matrix into a hot isostatic pressing furnace, and introduce argon gas with a purity of 99.999% into the furnace. Hold the furnace at a temperature of 1450℃ and a pressure of 125MPa for 3 hours to complete the strengthening treatment.

[0053] Finally, the mixture is cooled to room temperature at a cooling rate of 10℃ / min, and then machined to obtain the final tungsten carbide alloy.

[0054] Example 2 This embodiment provides a hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field, including the following steps: Step 1: Select tungsten carbide powder with an average particle size of 5 μm and a mass fraction of 96.7 wt% of the tungsten carbide powder. Add 3 wt% of cobalt powder and 0.3 wt% of nano-yttrium oxide powder to the tungsten carbide powder to obtain a mixed raw material powder.

[0055] The mixed raw material powder was placed in a ball mill, and anhydrous ethanol was added as the grinding medium. Hard alloy was used as the grinding balls for mixing. Then, it was spray-dried under the protective atmosphere of argon to obtain tungsten carbide composite powder.

[0056] Step 2: Select an elastomer mold with a cavity that closely resembles the finished tungsten carbide alloy, and coat its inner wall with boron nitride release agent; use paraffin wax as a molding agent, and load tungsten carbide composite powder with added paraffin wax into the mold.

[0057] Tungsten carbide composite powder is pressed into shape using a staged cold pressing process. The staged cold pressing process includes a low-pressure pressing stage and a high-pressure pressing stage. First, in the low-pressure pressing stage, the pressure is increased to 12MPa at a rate of 5MPa / min and held for 12min. Then, in the high-pressure pressing stage, the pressure is increased to 25MPa at a rate of 6MPa / min and held for 30min to obtain a cold-pressed green blank.

[0058] After the phased cold pressing process is completed, the cold-pressed green blank is placed in a vacuum heat treatment furnace and evacuated to a vacuum level of 8.9 × 10⁻⁶. -4 Pa is used to perform vacuum debinding and sintering, which includes a debinding stage and a sintering stage. First, in the debinding stage, the temperature is raised to 900°C at a rate of 5°C / min and held for 30 min before entering the sintering stage. Then, the temperature is raised to 1350°C at a rate of 10°C / min and held for 40 min to obtain a tungsten carbide alloy matrix.

[0059] Step 3: Transfer the tungsten carbide alloy matrix into a hot isostatic pressing furnace, and introduce argon gas with a purity of 99.999% into the furnace. Hold the furnace at a temperature of 1300℃ and a pressure of 160MPa for 4 hours to complete the strengthening treatment.

[0060] Finally, the mixture is cooled to room temperature at a cooling rate of 16℃ / min, and then machined to obtain the final tungsten carbide alloy.

[0061] Example 3 This embodiment provides a hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field, including the following steps: Step 1: Select tungsten carbide powder with an average particle size of 3μm and a mass fraction of 91.5wt% of the tungsten carbide powder. Add 8wt% of cobalt powder and 0.5wt% of nano-yttrium oxide powder to the tungsten carbide powder to obtain a mixed raw material powder.

[0062] The mixed raw material powder was placed in a ball mill, and deionized water was added as the grinding medium. Zirconia was used as the grinding balls for mixing. Then, it was spray-dried under the protective atmosphere of argon to obtain tungsten carbide composite powder.

[0063] Step 2: Select an elastomer mold with a cavity that closely resembles the finished tungsten carbide alloy, and coat its inner wall with boron nitride release agent; use polyethylene glycol as a molding agent, and load tungsten carbide composite powder with added polyethylene glycol into the mold.

[0064] Tungsten carbide composite powder is pressed into shape using a staged cold pressing process. The staged cold pressing process includes a low-pressure pressing stage and a high-pressure pressing stage. First, in the low-pressure pressing stage, the pressure is increased to 17MPa at a rate of 5MPa / min and held for 8 minutes. Then, in the high-pressure pressing stage, the pressure is increased to 23MPa at a rate of 6MPa / min and held for 50 minutes to obtain a cold-pressed green blank.

[0065] After the phased cold pressing process is completed, the cold-pressed green blank is placed in a vacuum heat treatment furnace and evacuated to a vacuum level of 5.5 × 10⁻⁶. -4 Pa is used to perform vacuum debinding and sintering, which includes a debinding stage and a sintering stage. First, in the debinding stage, the temperature is raised to 950°C at a rate of 5°C / min and held for 50 min before entering the sintering stage. Then, the temperature is raised to 1415°C at a rate of 10°C / min and held for 20 min to obtain a tungsten carbide alloy matrix.

[0066] Step 3: Transfer the tungsten carbide alloy matrix into a hot isostatic pressing furnace, and introduce argon gas with a purity of 99.999% into the furnace. Hold the furnace at a temperature of 1365℃ and a pressure of 145MPa for 2 hours to complete the strengthening treatment.

[0067] Finally, the mixture is cooled to room temperature at a cooling rate of 6℃ / min, and then machined to obtain the final tungsten carbide alloy.

[0068] Comparative Example 1 This comparative example provides a hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field, including the following steps: Step 1: Select tungsten carbide powder with an average particle size of 3μm and a mass fraction of 91.5wt% of the tungsten carbide powder. Add 8wt% of cobalt powder and 0.5wt% of nano-yttrium oxide powder to the tungsten carbide powder to obtain a mixed raw material powder.

[0069] The mixed raw material powder was placed in a ball mill, and deionized water was added as the grinding medium. Zirconia was used as the grinding balls for mixing. Then, it was spray-dried under the protective atmosphere of argon to obtain tungsten carbide composite powder.

[0070] Step 2: Select an elastomer mold with a cavity that closely resembles the finished tungsten carbide alloy, and coat its inner wall with boron nitride release agent; use polyethylene glycol as a molding agent, and load tungsten carbide composite powder with added polyethylene glycol into the mold.

[0071] Tungsten carbide composite powder was pressed into shape using a single cold pressing process. The pressure was increased to 23 MPa at a rate of 5 MPa / min and then held for 40 min to obtain a cold-pressed green blank.

[0072] After the single cold pressing process is completed, the cold-pressed green blank is placed in a vacuum heat treatment furnace and evacuated to a vacuum level of 5.5 × 10⁻⁶. -4 Pa is used to perform vacuum debinding and sintering, which includes a debinding stage and a sintering stage. First, in the debinding stage, the temperature is raised to 950°C at a rate of 5°C / min and held for 40 min before entering the sintering stage. Then, the temperature is raised to 1250°C at a rate of 10°C / min and held for 30 min to obtain a tungsten carbide alloy matrix.

[0073] Step 3: Transfer the tungsten carbide alloy matrix into a hot isostatic pressing furnace, and introduce argon gas with a purity of 99.999% into the furnace. Hold the furnace at a temperature of 1200℃ and a pressure of 145MPa for 3 hours to complete the strengthening treatment.

[0074] Finally, the mixture was cooled to room temperature at a cooling rate of 18℃ / min, and then machined to obtain the finished tungsten carbide alloy.

[0075] Table 1 Performance indicators of tungsten carbide alloys from Examples 1-3 and Comparative Example 1 Table 1 shows the differences in mechanical properties of tungsten carbide alloys prepared using different processes. Examples 1-3 were prepared using the complete process of this invention, while the process conditions of Comparative Example 1 deviated from the requirements of this invention. For all four groups of samples, the three key evaluation indicators—hardness, bending strength, and fracture toughness—were uniformly tested. Specifically, the process characteristic of Comparative Example 1 that differs from this invention is the use of single-stage cold pressing, and the sintering and hot isostatic pressing temperatures deviated from the range specified in this invention. A detailed analysis follows: First, addressing the shortcomings of traditional processes such as insufficient density and easy chipping during processing, Comparative Example 1 did not employ the staged cold pressing process of this invention, and its sintering and hot isostatic pressing temperatures did not match the process range of this invention. Consequently, the hardness and bending strength of the tungsten carbide alloy prepared in Comparative Example 1 were lower than those in Examples 1-3. In contrast, this invention, relying on the synergistic effect of powder refinement, staged cold pressing, vacuum debinding sintering, and hot isostatic pressing, achieves near-full densification of the tungsten carbide alloy. The bending strength of the three sets of examples can reach at least 3307 MPa, significantly improving the material's impact resistance and chipping resistance, effectively solving the problems of edge chipping and excessive dimensional deviations during high-speed semiconductor processing.

[0076] Secondly, addressing the shortcomings of traditional tungsten carbide cutting tools, such as insufficient wear resistance and short service life, the material hardness directly determines wear resistance. The tungsten carbide alloy prepared in Comparative Example 1 has a hardness of only 2120 HV, while the tungsten carbide alloys obtained in Examples 1-3 of this invention all have higher hardness than Comparative Example 1, with the tungsten carbide alloy in Example 3 reaching a hardness of over 2257 HV. On one hand, from a material mechanism perspective, fine-grained structures can rely on numerous grain boundaries to impede wear slip, and low-impurity structures can eliminate brittle corrosion phases at grain boundaries, simultaneously improving wear resistance and corrosion resistance. On the other hand, this invention achieves stable fine-grained, low-impurity microstructures through ball milling to refine powder, nano-yttrium oxide to regulate grain size, and high-purity argon gas throughout the entire process to control impurities and prevent oxidation. The combined effect of these two factors significantly enhances the wear resistance and chemical corrosion resistance of the finished product, effectively extending the tool's machining service life.

[0077] Third, addressing the shortcomings of existing technologies such as insufficient grain control precision and a single cobalt content formulation, making it difficult to adapt to various processing conditions, this invention achieves zoned control of mechanical properties by flexibly adjusting the amount of cobalt powder added. As shown in Table 1, the tungsten carbide alloy with a cobalt content of 3 wt% (Example 2) exhibits excellent hardness and is suitable for precision machining scenarios; the tungsten carbide alloy with a cobalt content of 8 wt% (Example 3) has a balanced match between hardness and fracture toughness, making it suitable for processing general semiconductor cutting tools and molds; and the tungsten carbide alloy with a cobalt content of 10 wt% (Example 1) has the best bending strength and fracture toughness, making it suitable for high-impact processing conditions such as rough milling of packaging slots and stamping of lead frames, effectively solving the problem that traditional single formulations cannot meet the differentiated hardness and toughness requirements of different processing conditions.

[0078] In summary, the integrated preparation process of this invention, combined with an adjustable cobalt powder ratio system, can simultaneously overcome multiple shortcomings of existing processes in terms of material density, wear and corrosion resistance, and grain size and composition control. The tungsten carbide alloy prepared by the method of this invention has adjustable strength and toughness, and a uniform and delicate internal structure, making it suitable for various precision machining conditions in semiconductors, effectively improving the chip processing yield and the service life of cutting tools and molds.

[0079] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0080] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing tungsten carbide products for the semiconductor field by hot isostatic pressing, characterized in that, Includes the following steps: Step 1: Add cobalt powder and yttrium oxide powder in a specific mass ratio to tungsten carbide powder to obtain a mixed raw material powder, wherein the mass ratio of the cobalt powder is compatible with the finished tungsten carbide alloy; add grinding media to the mixed raw material powder, mix and then dry to obtain tungsten carbide composite powder; Step 2: The tungsten carbide composite powder is loaded into a mold and pressed into shape using a staged cold pressing process to obtain a cold-pressed green blank; the cold-pressed green blank is then subjected to vacuum debinding and sintering to obtain a tungsten carbide alloy matrix. Step 3: After strengthening the tungsten carbide alloy matrix, cool it to room temperature using a specific cooling rate to finally obtain the finished tungsten carbide alloy.

2. The hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field according to claim 1, characterized in that, In step one, the tungsten carbide powder accounts for 89.2~96.7 wt% of the mass of the mixed raw material powder, the cobalt powder accounts for 3~10 wt% of the mass of the mixed raw material powder, and the yttrium oxide powder accounts for 0.3~0.8 wt% of the mass of the mixed raw material powder.

3. The hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field according to claim 2, characterized in that, When the hardness of the finished tungsten carbide alloy is 1700~2100HV, the mass percentage of cobalt powder in the mixed raw material powder is 3~8wt%.

4. The hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field according to claim 2, characterized in that, When the hardness of the finished tungsten carbide alloy is 1500~1800HV, the mass percentage of cobalt powder in the mixed raw material powder is 6~10wt%.

5. The hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field according to claim 1, characterized in that, In step two, the staged cold pressing process includes a low-pressure pressing stage and a high-pressure pressing stage in sequence; the pressure value of the low-pressure pressing stage is 12~17MPa, and the holding time is 8~12min; the pressure value of the high-pressure pressing stage is 20~25MPa, and the holding time is 30~50min.

6. The hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field according to claim 1, characterized in that, In step two, the vacuum degree used in the vacuum degreasing and sintering process is 10. -3 ~10 -4 Pa.

7. The hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field according to claim 1, characterized in that, In step two, the vacuum degreasing and sintering process includes a degreasing stage and a sintering stage in sequence; the temperature of the degreasing stage is 900~1000℃ and the holding time is 30~50min; the temperature of the sintering stage is 1350~1500℃ and the holding time is 20~40min.

8. The hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field according to claim 1, characterized in that, In step three, the strengthening treatment adopts hot isostatic pressing, with the following process parameters: temperature 1300~1450℃, pressure 120~160MPa, and holding time 2~4h.

9. The application of a tungsten carbide alloy in the preparation of tungsten carbide cutting tools and molds for the semiconductor field, characterized in that, The tungsten carbide alloy is prepared by the hot isostatic pressing method for preparing tungsten carbide products for the semiconductor field as described in any one of claims 1 to 8.

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