Nano-diamond graphite-like carbon composite coating cutter and preparation method and application thereof

Abstract

The invention provides a nano-diamond graphite-like carbon composite coating cutting tool and a preparation method and application thereof. The nano-diamond graphite-like carbon composite coating cutting tool comprises a hard alloy cutting tool, a nano-diamond layer and a graphite-like carbon layer, wherein the nano-diamond layer and the graphite-like carbon layer are sequentially arranged on the surface of the hard alloy cutting tool; and the nano-diamond layer and the graphite-like carbon layer are interlocked and meshed with each other. The nano-diamond layer and the graphite-like carbon layer are combined to construct the composite coating, and a unique structure is constructed on the bonding interface of the two layers, so that the nano-diamond layer and the graphite-like carbon layer are interlocked and meshed, the bonding force of the nano-diamond layer and the graphite-like carbon layer is enhanced, and the outer coating is not prone to falling off in the bonding process of the nano-diamond layer and the graphite-like carbon layer. The wear resistance and the deformation resistance of the cutter are improved through the high hardness of the nano-diamond layer, and the nano-diamond layer serves as a transition layer of the base material and the graphite-like carbon layer. The low friction coefficient and the low surface energy given by the unique structure of the graphite-like carbon are used for improving the anti-pollution capability of the chopper and reducing the metal adhesion in the bonding process, so that the capability of prolonging the service life of the chopper is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of cemented carbide tool processing, and particularly relates to a nano-diamond-like graphite carbon composite coating tool and its preparation method and application. Background Art

[0002] The core influence of the surface coating on tools such as splitting knives lies in significantly improving their anti-wear ability. By resisting the mechanical friction of metal wires on the surface during high-speed ultrasonic bonding, it slows down the dulling of the cutting edge and the increase in roughness, maintains stable bonding pressure conduction and solder joint morphology, and extends the tool life compared to uncoated splitting knives. Currently, a large amount of research focuses on improving the hardness of the splitting knife coating, such as using transition metal nitrides (CrN, TiN), carbides, etc. However, these materials are difficult to meet the increasingly complex performance requirements in the evolving bonding needs. The hardness of traditional TiN coatings gradually decreases during the process of increasing temperature, increasing the wear rate by 10 times. In addition, with the development of the manufacturing industry towards high-precision and complex processing directions, single-functional coatings are no longer able to meet the comprehensive performance requirements during the bonding process. In response to the dual requirements of wear resistance and lubricity in high-load bonding, multi-component composite coatings with both high-hardness wear-resistant phases and low-friction coefficient lubricating phases have emerged, achieving a synergistic effect of "hard support - soft lubrication" through composition design; to cope with the impact load of continuous bonding, multi-layer coatings with a tough transition layer and a hard surface layer and gradient coating technology with a gradually changing composition gradient have developed rapidly. The smooth transition of the interlayer mechanical properties can effectively inhibit crack initiation and propagation and improve the coating's anti-spalling ability. Although composite coatings have extended the tool life, they still face defects such as insufficient hardness, deteriorated wear resistance, intolerance to high temperatures, chemical corrosion, and surface contamination; and the interfacial bonding force between each coating is not strong enough. This will cause partial spalling of the coating due to the high temperature generated during rapid bonding, greatly affecting the tool life. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. For this reason, one of the objectives of the present invention is to propose a nano-diamond-like graphite carbon composite coating tool.

[0004] Another objective of the present invention is to propose a preparation method for the above-mentioned nano-diamond-like graphite carbon composite coating tool.

[0005] A further objective of the present invention is to propose the application of the above-mentioned nano-diamond-like graphite carbon composite coating tool.

[0006] The first aspect of the present invention provides a nano-diamond-like graphite carbon composite coating tool, including a cemented carbide tool and a nano-diamond layer and a graphite-like carbon layer sequentially arranged on the surface of the cemented carbide tool; the nano-diamond layer and the graphite-like carbon layer are interlocked and meshed.

[0007] According to some embodiments of the present invention, the nanodiamond layer and the graphene-like layer are interlocked and meshed through a nano-microarray structure.

[0008] According to some embodiments of the present invention, in the nanodiamond layer, the average diameter of the diamond particles is 100 - 500 nm.

[0009] According to some embodiments of the present invention, in the graphene-like carbon layer, the average diameter of the graphene-like carbon is 10 - 100 nm.

[0010] According to some embodiments of the present invention, the thickness of the nanodiamond layer is 0.2 - 25.0 µm.

[0011] According to some embodiments of the present invention, the thickness of the graphene-like carbon layer is 0.1 - 1.0 µm.

[0012] According to some embodiments of the present invention, the cemented carbide cutting tool includes any one of a splitting tool, a twist drill, a reamer, a boring tool, a ball end mill, a saw blade mill, a taper mill, an indexable end mill, an indexable face mill, an indexable dovetail mill, and an indexable three-edge mill, etc.

[0013] The second aspect of the present invention provides a method for preparing the nanodiamond graphene-like carbon composite coating cutting tool as described above, comprising the following steps: S1: Prepare the nanodiamond layer: Deposit a nanodiamond layer on the surface of the cemented carbide cutting tool; Etch the nanodiamond layer to form an interface with a nano-microarray structure; S2: Prepare the graphene-like carbon layer: Deposit a graphene-like carbon layer on the interface with a nano-microarray structure to obtain the nanodiamond graphene-like carbon composite coating cutting tool.

[0014] According to some embodiments of the present invention, in S1, the nanodiamond layer is grown by chemical vapor deposition; the chemical vapor deposition method includes the hot filament chemical vapor deposition (HFCVD) method.

[0015] According to some embodiments of the present invention, the growth of the diamond layer by the hot filament chemical vapor deposition method includes first growing nuclei and then growing the diamond layer; the specific process parameters include: using hydrogen, methane, and optionally an inert gas as reaction gases, methane: 20 - 50 sccm, hydrogen: 500 - 1000 sccm, power: 5500 - 7500 W, growth pressure: 1000 - 3000 Pa, filament-bottom distance: 10 - 20 mm; wherein, deposit for 10 - 30 min to grow nuclei first, and then deposit for 2 - 6 h to grow the diamond layer.

[0016] According to some embodiments of the present invention, the method for preparing the nano-diamond-like graphite carbon composite coating tool further includes pre-treating the cemented carbide tool and then depositing a nano-diamond layer on the surface of the pre-treated cemented carbide tool.

[0017] According to some embodiments of the present invention, the pre-treatment includes ultrasonic cleaning; the specific operation of the ultrasonic cleaning is: sequentially ultrasonic clean the cemented carbide tool in acetone solution, deionized water, and absolute ethanol solution for 5 - 20 min respectively.

[0018] According to some embodiments of the present invention, the method for preparing the nano-diamond-like graphite carbon composite coating tool further includes a step of pre-seeding on the surface of the cemented carbide tool.

[0019] According to some embodiments of the present invention, the step of pre-seeding includes: placing the cemented carbide tool in a diamond powder suspension and performing ultrasonic treatment.

[0020] According to some embodiments of the present invention, in S1, the etching includes plasma etching and / or chemical etching.

[0021] According to some embodiments of the present invention, the plasma etching is carried out in a magnetron sputtering device; the process parameters of the plasma etching include: the vacuum chamber pressure range is below 10 -5 Pa, turn on the plasma cleaning source, the Ar gas flow rate is 80 - 150 sccm, the radio frequency power is 30 - 80 W, the bias voltage is 80 - 150 V, and the treatment time is 10 - 30 min.

[0022] According to some embodiments of the present invention, in S2, the graphite-like carbon layer is deposited by physical vapor deposition; the physical vapor deposition is carried out in a radio frequency magnetron sputtering device, and the specific process parameters include: the graphite target used has a micro-purity of ≥99.99%, the temperature range of the cemented carbide tool during treatment is 150 - 250 °C, the Ar gas flow rate is 10 - 50 sccm, the target power is 100 - 200 W, the bias power supply is 0 - 50 V (such as 5 - 40 V), the substrate rotation rate is 5 - 10 rpm, and the deposition time is 1 - 3 h.

[0023] According to some embodiments of the present invention, the method for preparing the nano-diamond-like graphite carbon composite coating tool further includes S3: an annealing step.

[0024] According to some embodiments of the present invention, the specific operation of the annealing includes: placing the cemented carbide tool deposited with the diamond layer and the graphitic carbon layer in a furnace with an Ar atmosphere, controlling the heating rate to be 1-10 °C / min, the Ar gas flow rate to be 85-100 sccm, the temperature in the furnace to be 300-400 °C, maintaining for 1-2 h, and then cooling naturally.

[0025] According to some embodiments of the present invention, the preparation method of the nano-diamond / graphitic carbon composite coating tool further includes S4: a step of polishing.

[0026] According to some embodiments of the present invention, the specific operation of the polishing includes: polishing the annealed cemented carbide tool using a precision polishing machine, and the polishing materials include diamond spray liquid (particle size of 1-10 µm) and polishing pads; the specific process parameters include: the rotation speed of the turntable: 100-500 rpm, the load pressure: 0.5-2 N, and the time: 5-10 min.

[0027] The third aspect of the present invention provides an application of a nano-diamond / graphitic carbon composite coating tool in wire bonding for semiconductor packaging, flip chip bonding and / or hybrid bonding for advanced packaging, cutting of ceramic / glass substrates for precision machining, or micro-nano structure machining. The nano-diamond / graphitic carbon composite coating tool includes the aforementioned nano-diamond / graphitic carbon composite coating tool, or is prepared by the preparation method of the aforementioned nano-diamond / graphitic carbon composite coating tool.

[0028] The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0029] Figure 1 is a flow chart showing the preparation method of the split blade with a composite coating in Example 1 of the present invention.

[0030] Figure 2 is a process flow chart of the composite coating of the present invention.

[0031] Figure 3 is a metallurgical microscope photograph of the split blade with a composite coating in Example 1 of the present invention.

[0032] Figure 4 is an SEM image of the split blade with a composite coating in Example 1 of the present invention.

[0033] Figure 5 is an SEM image of the interlocking structure formed by nano-diamond and graphitic carbon layers in Example 1 of the present invention.

[0034] Figure 6This is a SEM picture of the composite coating splitter in Example 1 of the present invention after being used for a period of time. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0037] The first aspect of the present invention provides a nano-diamond graphite-like carbon composite coating tool, comprising a cemented carbide tool and a nano-diamond layer and a graphite-like carbon layer sequentially arranged on the surface of the cemented carbide tool; the nano-diamond layer and the graphite-like carbon layer are interlocked and meshed.

[0038] According to the first aspect of the present invention, there are at least the following beneficial effects: In the present invention, a nano-diamond layer is combined with a graphite-like carbon layer to construct a composite coating, and a unique structure is constructed at the interface between the two layers, so that the nano-diamond layer and the graphite-like carbon layer form an interlocking mesh, thereby enhancing the bonding force between the two and making it difficult for the outer coating to fall off during the bonding process. The high hardness of the nano-diamond layer is used to improve the wear resistance and deformation resistance of the tool, and it is used as a transition layer between the substrate and the graphite-like carbon layer. The low friction coefficient and low surface energy given by the unique structure of graphite-like carbon are used to improve the anti-fouling ability of the splitting knife and reduce metal adhesion during the bonding process, thereby achieving the ability to increase the service life of the splitting knife. Specifically: Compared with other existing technologies that use high-hardness wear-resistant phases such as TiC and CrN in the transition layer, nanodiamond has higher hardness and better thermal stability. Higher hardness can ensure that cemented carbide tools can be bonded more times, and excellent thermal stability can withstand the instantaneous high temperature caused by multiple bonding and ensure the integrity of the splitter structure. In addition, the thermal expansion coefficient of diamond as a transition layer is similar to that of TiC, CrN, etc., so that it can adhere well to the surface of cemented carbide tools. The nanometer-level particle size on the surface of nanodiamond can firmly deposit subsequent graphite-like carbon.

[0039] Surface energy refers to the additional non - volume work required to reversibly expand the surface area of an object at constant temperature and pressure. Essentially, it is the additional potential energy carried by the atoms on the solid surface due to the incomplete compensation of bond energy. The surface energy of cemented carbide tools such as splitters directly affects the bonding quality. When in contact and friction with metals such as aluminum, silver, and copper under high - speed and high - frequency ultrasound, their high surface energy will adsorb metals to form a dirty layer. The function of low - friction coefficient on the surface of cemented carbide tools such as splitters brings many advantages: it can not only significantly reduce the adsorption force when in contact with metal wires such as aluminum and copper under high - speed bonding, inhibit the deposition of metal atoms and the accumulation of dirty layers caused by mechanical friction and surface - energy attraction, but also reduce the interfacial energy loss to lower the frictional temperature rise (avoiding thermal deformation of the splitter and bonding accuracy deviation caused by local overheating). At the same time, it slows down the increase in roughness and the expansion of the effective surface area caused by surface micro - wear, thereby maintaining stable wettability and ultrasonic energy transfer efficiency, ultimately improving the solder joint quality and extending the tool life. Currently, mainstream coating materials such as CrN and TiN have relatively high friction coefficients and large surface energies, resulting in a decrease in the flatness and wettability of the splitter surface after a certain number of bonding times and a shortened service life.

[0040] Graphitic carbon is an allotrope composed of carbon elements, with both the crystal structures of graphite and diamond - the carbon atoms are mainly sp 2 hybridized, supplemented by sp 3 hybridization. This structure endows it with a series of excellent properties. On the one hand, it has good electrical conductivity, thermal conductivity, high - temperature resistance, chemical stability, and self - lubricity; on the other hand, it also inherits some hardness characteristics of diamond and is a new type of multifunctional material. In the field of cemented carbide tools, graphitic carbon shows great advantages: (1) Low friction coefficient and low surface energy: Graphitic carbon can significantly reduce the frictional resistance and heat accumulation during the cutting process of the tool, slow down tool wear, and the layered structure reduces the contact - surface loss through inter - layer slip during high - speed friction, extending the tool life and meeting the high - frequency and high - precision bonding requirements; (2) Excellent thermal management ability: Instantaneous high temperatures are generated during the bonding process. The high thermal conductivity of graphitic carbon can quickly conduct heat away, avoiding solder - joint oxidation or splitter deformation caused by local overheating and ensuring process stability; (3) Chemical stability and anti - pollution: Graphitic carbon is inert to metal solders (such as gold, silver, and aluminum) and fluxes, is not prone to chemical reactions or adhesion, reduces solder - joint impurities and defects, and improves product yield.

[0041] Therefore, a graphitic - carbon layer is set on the nano - diamond layer, and an interlocking structure is formed at the bonding interface between the two to improve the inter - layer bonding force of the composite coating (such as Figure 5 ), thereby significantly improving the anti - pollution ability of the cemented carbide tool (such as Figure 6 ), reducing its wear rate, decreasing its over - heat deformation, and comprehensively improving its service life.

[0042] According to some embodiments of the present invention, the nanodiamond layer and the graphene-like layer are interlocked and meshed through a nano-microarray structure.

[0043] According to some embodiments of the present invention, the microarray structure refers to a structure with a micro-protrusion or ripple array on the surface; the micro-protrusion or ripple array is arranged in an orderly manner; the micro-protrusion or ripple array has uniformity.

[0044] According to some embodiments of the present invention, in the nanodiamond layer, the average diameter of diamond particles is 100 - 500 nm, such as 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 500 nm, etc.

[0045] According to some embodiments of the present invention, in the graphene-like carbon layer, the average diameter of graphene-like carbon is 10 - 100 nm, such as 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, etc.

[0046] According to some embodiments of the present invention, the nanodiamond layer contains silicon carbide; the content of silicon carbide is 10 - 50 wt% (such as 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%). In the present invention, adding silicon carbide to the diamond layer can improve the interfacial bonding force between the nanodiamond layer and the cemented carbide tool substrate.

[0047] According to some embodiments of the present invention, the nanodiamond layer is doped with boron (B) and / or phosphorus (P); the doping amounts of boron (B) and / or phosphorus (P) are 100 - 10,000 ppm respectively (such as 500 ppm, 1000 ppm, 3000 ppm, 5000 ppm, 7000 ppm, 9000 ppm); in the present invention, doping boron (B) and / or phosphorus (P) in the diamond layer can further improve its wear resistance.

[0048] According to some embodiments of the present invention, the graphene-like carbon layer is doped with silicon (Si); the doping amount of silicon (Si) is 100 - 10,000 ppm (such as 500 ppm, 1000 ppm, 3000 ppm, 5000 ppm, 7000 ppm, 9000 ppm); in the present invention, doping silicon in the graphene-like carbon layer can further improve the hardness of the graphene-like carbon.

[0049] According to some embodiments of the present invention, the thickness of the nanodiamond layer is 0.2 - 25.0 µm, such as 1.0 - 4.0 µm, 1.0 µm, 1.5 µm, 1.9 µm, 2.4 µm, 3.0 µm, 3.6 µm, etc.

[0050] According to some embodiments of the present invention, the thickness of the graphitic carbon layer is 0.1 - 1.0 µm, such as 0.2 - 0.8 µm, 0.2 µm, 0.3 µm, 0.4 µm, 0.5 µm, 0.7 µm, etc.

[0051] According to some embodiments of the present invention, the cemented carbide cutting tool includes any one of a splitting tool, a twist drill, a reamer, a boring tool, a ball end mill, a saw blade mill, a taper mill, an indexable end mill, an indexable face mill, an indexable dovetail mill, and an indexable side milling cutter with three cutting edges, etc.

[0052] According to some embodiments of the present invention, the splitting tool includes any one of a gold ball bonding splitting tool, a wedge bonding splitting tool, and a thermocompression bonding splitting tool.

[0053] In the second aspect of the present invention, a method for preparing the above-mentioned nano-diamond graphitic carbon composite coating cutting tool is provided, including the following steps: S1: Prepare a nano-diamond layer: Deposit a nano-diamond layer on the surface of the cemented carbide cutting tool; etch the nano-diamond layer to form an interface with a nano-microarray structure; S2: Prepare a graphitic carbon layer: Deposit a graphitic carbon layer on the interface with a nano-microarray structure to obtain the above-mentioned nano-diamond graphitic carbon composite coating cutting tool.

[0054] According to the embodiments of the second aspect of the present invention, it has at least the following beneficial effects: In the present invention, after depositing the nano-diamond layer, the nano-diamond layer is etched to form a nano-microarray structure on its surface, and then the graphitic carbon layer is deposited, thereby forming an interlocking engagement.

[0055] According to some embodiments of the present invention, in S1, the nano-diamond layer is grown by chemical vapor deposition; the chemical vapor deposition method includes a hot filament chemical vapor deposition (HFCVD) method. The hot filament chemical vapor deposition method (hot filament CVD) is one of the chemical vapor deposition methods. The hot filament chemical vapor deposition method is not limited, and a conventional hot filament chemical vapor deposition device and / or process can be used, which can be a common hot filament method or other improved forms of hot filament method such as electron-assisted.

[0056] According to some embodiments of the present invention, the method for growing a diamond layer by hot filament chemical vapor deposition includes first growing nuclei and then growing a diamond layer; the specific process parameters include: using hydrogen, methane, and optionally an inert gas as reaction gases, methane: 20 - 50 sccm, hydrogen: 500 - 1000 sccm, power: 5500 - 7500 W, growth gas pressure: 1000 - 3000 Pa, distance from the filament bottom: 10 - 20 mm; wherein, nuclei are deposited for 10 - 30 min first to grow nuclei, and then a diamond layer is deposited for 2 - 6 h.

[0057] According to some embodiments of the present invention, the method for preparing the nano - diamond - like graphite - carbon composite coating tool further includes pre - treating the cemented carbide tool first and then depositing a nano - diamond layer on the surface of the pre - treated cemented carbide tool.

[0058] According to some embodiments of the present invention, the pre - treatment includes ultrasonic cleaning; the specific operation of the ultrasonic cleaning is: successively ultrasonic - cleaning the cemented carbide tool in acetone solution, deionized water, and absolute ethanol solution for 5 - 20 min respectively.

[0059] According to some embodiments of the present invention, the method for preparing the nano - diamond - like graphite - carbon composite coating tool further includes a step of pre - seeding on the surface of the cemented carbide tool; preferably, it includes a step of pre - seeding on the surface of the pre - treated cemented carbide tool.

[0060] According to some embodiments of the present invention, the step of pre - seeding includes: placing the cemented carbide tool in a diamond powder suspension and performing ultrasonic treatment.

[0061] According to some embodiments of the present invention, the concentration of the diamond powder suspension is 2 - 5 wt%.

[0062] According to some embodiments of the present invention, the average particle size of the diamond powder is 50 - 500 nm.

[0063] According to some embodiments of the present invention, the dispersion medium of the diamond powder suspension is absolute ethanol or deionized water.

[0064] According to some embodiments of the present invention, the time of the ultrasonic treatment is 10 - 30 min.

[0065] According to some embodiments of the present invention, in S1, the etching includes plasma etching and / or chemical etching. In the present invention, the surface morphology of the nanodiamond layer grown by chemical deposition is inevitably uneven, which will affect its subsequent interfacial affinity with the graphitic carbon layer. By exciting argon gas (Ar) with a radio frequency (RF) power supply to generate glow discharge plasma, and using the directional bombardment of high-energy argon ions therein, the surface of the nanodiamond is subjected to plasma etching treatment. In this process, the surface disordered protrusion regions and abnormally sized particles are selectively removed through a physical sputtering mechanism, prompting the nanodiamond particles with relatively large initial particle size differences to be refined and tend to be uniform through edge sputtering, and constructing spherical-like particles to avoid sharp diamond grains from scratching the bonding surface and causing metal chip adhesion, and making their surfaces have an orderly arrangement of the structure and a uniform particle size, so as to form a structural interlock with the graphitic carbon layer (as Figure 5 shown); and the ordering of the surface microstructure and the uniform particle size treatment ensure that the coating nucleation sites are evenly distributed, avoiding uneven coating thickness caused by local protrusions, thereby significantly improving its bonding strength with the subsequent deposited coating; using chemical etching can reduce the particle size on the surface of the nanodiamond, improve the degree of order of particle arrangement, and form a nano-microarray structure.

[0066] According to some embodiments of the present invention, the plasma etching is carried out in a magnetron sputtering device; the process parameters of the plasma etching include: the vacuum chamber air pressure range is below 10 -5 Pa, turn on the plasma cleaning source, the Ar gas flow rate is 80~150 sccm, the radio frequency power is 30~80 W, the bias voltage is 80~150 V, and the treatment time is 10~30 min.

[0067] According to some embodiments of the present invention, in S2, the graphitic carbon layer is deposited by physical vapor deposition; the physical vapor deposition is carried out in a radio frequency magnetron sputtering device, and the specific process parameters include: the graphite target used has a micro purity of ≥99.99%, the temperature range of the cemented carbide tool during treatment is 150~250 °C, the Ar gas flow rate is 10~50 sccm, the target power is 100~200 W, the bias power supply is 0~50 V (such as 5~40 V), the substrate rotation rate is 5~10 rpm, and the deposition time is 1~3 h. In the present invention, the graphitic carbon coating deposited by the magnetron sputtering device is more uniform and has a lower cost. In addition, compared with the CVD method, the temperature for generating the graphitic carbon layer on the bonding tool substrate is lower, reducing the degree of influence of high temperature on the substrate itself and avoiding the reduction of the body strength caused by too high substrate temperature.

[0068] According to some embodiments of the present invention, the physical vapor deposition can also be carried out in a direct current magnetron sputtering coating device.

[0069] According to some embodiments of the present invention, the method for preparing the nano-diamond-like graphite carbon composite coating tool further includes S3: an annealing step. In the present invention, annealing measures are used to eliminate the internal stress in the coating during the deposition process, further improve the mechanical strength of the coating, and at the same time improve the wear resistance of the graphite-like carbon layer and further reduce the friction coefficient; the annealing treatment can also further strengthen the interfacial bonding force between the cemented carbide tool substrate and the nano-diamond layer and the graphite-like carbon layer, and reduce the risk of coating cracking.

[0070] According to some embodiments of the present invention, the specific operation of the annealing includes: placing the cemented carbide tool deposited with the diamond layer and the graphite-like carbon layer in a furnace with an Ar atmosphere, controlling the heating rate to be 1-10 °C / min, the Ar gas flow rate to be 85-100 sccm, the temperature in the furnace to be 300-400 °C, maintaining for 1-2 h, and then cooling naturally.

[0071] According to some embodiments of the present invention, the method for preparing the nano-diamond-like graphite carbon composite coating tool further includes S4: a polishing and grinding step. In the present invention, polishing and grinding the coating of the cemented carbide tool can further reduce its surface roughness.

[0072] According to some embodiments of the present invention, the specific operation of the grinding and polishing includes: grinding the annealed cemented carbide tool using a precision polishing machine, and the grinding materials include diamond spray liquid (particle size of 1-10 µm) and a polishing pad; the specific process parameters include: the turntable speed: 100-500 rpm, the load pressure: 0.5-2 N, and the time: 5-10 min.

[0073] According to some embodiments of the present invention, the method for preparing the nano-diamond-like graphite carbon composite coating tool includes the following steps: S0: Pretreatment, first ultrasonically clean the cemented carbide tool; S1: Prepare the nano-diamond layer, deposit the nano-diamond layer on the surface of the pretreated cemented carbide tool; etch the nano-diamond layer using plasma to form an interface with a nano-microarray structure; S2: Prepare the graphite-like carbon layer, deposit the graphite-like carbon layer on the interface with the nano-microarray structure by physical vapor deposition; S3: Annealing, anneal the cemented carbide tool deposited with the diamond layer and the graphite-like carbon layer; S4: Polishing and grinding, grind the annealed cemented carbide tool using a precision polishing machine to obtain the nano-diamond-like graphite carbon composite coating tool.

[0074] In the third aspect of the present invention, there is provided an application of a nano-diamond-like graphite carbon composite coating tool in wire bonding for semiconductor packaging, flip-chip bonding and / or hybrid bonding for advanced packaging, cutting of ceramic / glass substrates for precision machining, or micro-nano structure machining. The nano-diamond-like graphite carbon composite coating tool includes the aforementioned nano-diamond-like graphite carbon composite coating tool, or is prepared by the preparation method of the aforementioned nano-diamond-like graphite carbon composite coating tool.

[0075] The content of the present invention will be further described in detail through specific examples below.

[0076] The raw materials in the following examples or comparative examples can all be obtained from conventional commercial channels, or can be obtained by existing technical methods.

[0077] Example 1 In this example, a wedge bonding tool with a composite coating is prepared. The preparation process of the composite coating is as follows Figure 1 、 Figure 2 and includes the following steps: 1) Cleaning the surface of the wedge bonding tool: The wedge bonding tool without deposited coating is cleaned by an ultrasonic device to remove impurities on its surface. The wedge bonding tool is ultrasonically cleaned in acetone solution for 10 min, in deionized water for 10 min, and in absolute ethanol solution for 10 min. Finally, the cleaned wedge bonding tool is dried.

[0078] 2) Growing a nano-diamond thin film on the surface of the wedge bonding tool: The hot filament CVD method is selected to prepare a diamond thin film layer with a micron-level thickness on the surface of the wedge bonding tool. First, the surface of the wedge bonding tool needs to be pre-seeded with crystals to facilitate the subsequent growth of nano-diamonds. Specifically, the cleaned wedge bonding tool is ultrasonically treated in a nano-diamond dispersion liquid. The specific parameters are as follows: nano-diamond particle size: 100 nm, dispersion liquid: absolute ethanol or deionized water, ultrasonic time: 10 min. The cleaned wedge bonding tool substrate is placed on a molybdenum substrate stage and placed in a CVD device, and the vacuum is pumped to below 10 -5 Pa. Then, the seeded wedge bonding tool is nucleated by the hot filament chemical vapor deposition method: methane: 32 sccm, hydrogen: 800 sccm, power: 6800 W, growth pressure: 1500 Pa, distance from the filament bottom: 14 mm, time: 10 min. Finally, the growth of nano-diamonds starts. The specific parameters are as follows: methane: 60 sccm, hydrogen: 800 sccm, power: 6800 W, growth pressure: 1500 Pa, distance from the filament bottom: 18 mm, and deposition time: 6 h. The thickness of the nano-diamond thin film is 3 µm.

[0079] 3) Etching the nano-diamond coating by plasma: Put the wedge for growing the nanodiamond coating into a magnetron sputtering device, and evacuate to below 10 -5 Pa. Turn on the plasma cleaning source, and the specific parameters are as follows: Ar gas flow rate is 100 sccm, radio frequency power is 50 W, bias voltage is 100 V, and the processing time is 20 min.

[0080] 4) Continuously sputter a graphitic carbon coating on the surface of the nanodiamond layer: After the plasma cleaning source etches, directly use this magnetron sputtering device to sputter the graphitic carbon coating. The target used is a graphite target with a purity of ≥99.99%. Turn off the plasma cleaning source and Ar gas. After the substrate temperature drops to room temperature, evacuate to below 10 -5 Pa. Then turn on the heating device to control the temperature of the wedge substrate at about 200 °C, and then start sputtering. The parameters are as follows: Ar gas flow rate: 40 sccm, target power: 200 W, bias power supply: 50 V, substrate rotation rate: 5 rpm, deposition time: 1.5 h. The thickness of the graphitic carbon coating is 500 nm.

[0081] 5) Anneal to eliminate the stress between the coatings and increase the interfacial affinity between the coatings: Put the wedge with the deposited coating into a tube furnace, turn on the Ar gas flow to remove the air in the tube to form a pure Ar environment, and then start annealing. The specific parameters are as follows: heating rate: 2 °C / min, Ar gas flow rate: 90 sccm, furnace temperature: 350 °C, holding time: 1.5 h, and natural cooling.

[0082] 6) Polish and grind the prepared wedge coating to further reduce the surface roughness: Use a precision polishing machine to polish, and fix the wedge sample in the sample fixture. Polishing materials: diamond spray liquid (particle size: 10 nm), polishing pad. Specific parameters: turntable rotation speed: 100 rpm, load pressure: 2 N, time: 10 min.

[0083] Figure 3 is the metallographic microscope photograph of the wedge in Example 1; Figure 4 is the SEM image of the bonding working surface of the wedge in Example 1. Figure 5 is the SEM image of the interlocking structure formed by the nanodiamond and the graphitic carbon layer in Example 1 of the present invention. Figure 6 is the SEM image of the wedge with the composite coating after being used for a period of time in Example 1 of the present invention.

[0084] From Figure 3 and Figure 4 it can be seen that the nanodiamond has been deposited on the tool substrate, and the front SEM image shows that the graphitic carbon layer has been well deposited on the nanodiamond layer and is sputtered relatively uniformly. Figure 5It can be seen that the graphitic carbon layer is well deposited on the spherical nanodiamonds to form an interlocking structure. After using for a period of time, there is no obvious metal adhesion and coating peeling on the surface of the wedge tool. Figure 6 ) This indicates that the interlocking structure significantly enhances the interfacial affinity and improves the anti-fouling ability of the tool.

[0085] Examples 2 - 3, Comparative Examples 1 - 4 The differences between Examples 2 - 3, Comparative Examples 1 - 3 and Example 1 lie in that some steps in the preparation process of the wedge tool with a composite coating are omitted.

[0086] Comparative Example 4 prepares a wedge tool with a composite coating. The difference in its preparation method from Example 1 is that a cubic boron nitride layer is set on the diamond layer. The specific preparation method is as follows: Steps 1) to 3), step 5), and step 6) refer to Example 1. 4) Continuously sputter a cubic boron nitride coating on the surface of the nanodiamond layer: After being etched by the plasma cleaning source, directly use this magnetron sputtering device to sputter a graphitic carbon coating. The target used is a BN target with a purity ≥ 99.99%. Turn off the plasma cleaning source and Ar gas. After the substrate temperature drops to room temperature, evacuate to below 10 -5 Pa. Subsequently, turn on the heating device to control the temperature of the wedge tool substrate at about 200 °C, and then start sputtering. The parameters are as follows: N2 flow rate: 60 sccm, Ar gas flow rate: 40 sccm, target power: 200 W, negative bias power supply: 50 V, substrate rotation rate: 5 rpm, deposition time: 1 h. The thickness of the cubic boron nitride coating is 500 nm.

[0087] Examples 1 - 3, Comparative Examples 1 - 4 are specifically shown in Table 1, and the lifespan of the corresponding wedge tools is tested. After the tool with the composite coating is bonded a certain number of times and then cleaned, it can be used continuously. Therefore, in all the following wedge tool lifespan tests, the wedge tools will be cleaned and then tested again to increase the maximum service life.

[0088] Table 1

[0089] a: The number of times of the wedge tool lifespan is recorded and valued by the wire bonder.

[0090] As can be seen from Table 1, the annealing step in step 5) and the polishing step in step 6) can further improve the service life of the wedge tool. However, in Comparative Example 1, the graphitic carbon layer is deposited without etching the diamond layer. In Comparative Example 2, the diamond layer is not deposited. In Comparative Example 3, the graphitic carbon layer is not deposited. All of these will significantly reduce the lifespan of the wedge tool. The wedge tool in Example 1 shows the best lifespan performance.

[0091] Examples 4 - 14 Examples 4 to 14: A bonding tool with a composite coating is prepared. The difference in the preparation method from Example 1 lies in that the specific parameters of growing the nanodiamond layer by hot wire CVD in step 2) are different. Specifically, the longer the deposition time, the higher the methane concentration, and the smaller the distance between the wire and the substrate, the thicker the nanodiamond layer will be. The remaining steps refer to Example 1. The life test of the obtained bonding tool is carried out. The parameters used in the examples and the life of the bonding tool are shown in Table 2 below.

[0092] Table 2

[0093] As can be seen from Table 2, changing different parameters of hot wire CVD will change the thickness of the grown nanodiamond, thereby affecting the life of the bonding tool. Especially when changing the methane gas flow rate and the distance between the wire and the substrate, its life will be affected. This is because the change of parameters will affect the quality of the grown nanodiamond, and its coating hardness and interfacial bonding force will be affected.

[0094] Examples 15 to 21 In Examples 15 to 21, a bonding tool with a composite coating is prepared. The difference in the preparation method from Example 1 lies in that the parameters of magnetron sputtering deposition of the graphite-like carbon layer in step 4) are different. Specifically, the larger the Ar gas flow rate, the higher the target power, and the longer the deposition time, the thicker the sputtered graphite-like carbon layer will be. The parameters of the remaining steps are the same. At the same time, the life test of the bonding tools of different examples is carried out. The parameters used in the examples and the life of the bonding tool are shown in Table 3 below.

[0095] Table 3

[0096] As can be seen from Table 3, changing different parameters of magnetron sputtering will affect the life of the bonding tool. Especially when changing the Ar gas flow rate and the target power, its life will be greatly affected. This is because the change of parameters will affect the uniformity of the deposited graphite-like carbon layer and cause changes in internal stress, affecting its interfacial bonding force, surface energy, and friction coefficient, etc.

[0097] In the description of this specification, the description referring to the term "some embodiments" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above term does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0098] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A nano-diamond-like graphite carbon composite coating cutting tool, characterized in that: It includes a cemented carbide cutting tool, a nanodiamond layer, and a graphitic carbon layer sequentially provided on the surface of the cemented carbide cutting tool; the nanodiamond layer and the graphitic carbon layer are interlocked and meshed with each other.

2. The nano-diamond-like graphite carbon composite coating tool according to claim 1, wherein: The nanodiamond layer and the graphene-like layer are interlocked and meshed through a nano-microarray structure.

3. The nano-diamond-like graphite carbon composite coating tool according to claim 1, characterized in that: In the nanodiamond layer, the average diameter of diamond particles is 100~500 nm; preferably, the thickness of the nanodiamond layer is 0.2~25.0 µm.

4. The nano-diamond-like graphite carbon composite coating tool according to claim 1, wherein: In the graphitic carbon layer, the average diameter of graphitic carbon is 10~100 nm; preferably, the thickness of the graphitic carbon layer is 0.1~1.0 µm.

5. The nano-diamond-like graphite carbon composite coating tool according to claim 1, wherein: The cemented carbide cutting tool includes any one of a splitting tool, a twist drill, a reamer, a boring tool, a ball end mill, a saw blade mill, a taper mill, a indexable end mill, an indexable face mill, an indexable dovetail mill, and an indexable three-edge milling cutter.

6. A method for preparing a nano-diamond-like graphite carbon composite coating tool according to any one of claims 1 to 5, characterized in that: It includes the following steps: S1: Prepare the nanodiamond layer: Deposit the nanodiamond layer on the surface of the cemented carbide cutting tool; etch the nanodiamond layer to form an interface with a nano-microarray structure. S2: Prepare the graphitic carbon layer: Deposit the graphitic carbon layer on the interface with the nano-microarray structure to obtain the nanodiamond-graphitic carbon composite coating cutting tool.

7. The preparation method of the nano-diamond-like graphite carbon composite coating tool according to claim 6, characterized in that: In S1, the nanodiamond layer is grown by chemical vapor deposition; preferably, the chemical vapor deposition method includes the hot filament chemical vapor deposition method.

8. The preparation method of the nano-diamond-like graphite carbon composite coating tool according to claim 7, characterized in that: The growth of the diamond layer by the hot filament chemical vapor deposition method includes first growing nuclei and then growing the diamond layer; the specific process parameters include: using hydrogen, methane, and optionally an inert gas as reaction gases, methane: 20~50 sccm, hydrogen: 500~1000 sccm, power: 5500~7500 W, growth gas pressure: 1000~3000 Pa, filament-bottom distance: 10~20 mm; among them, first deposit for 10~30 min to grow nuclei, and then deposit for 2~6 h to grow the diamond layer.

9. The preparation method of the nano-diamond-like graphite carbon composite coating tool according to claim 6, characterized in that: The preparation method of the nanodiamond-graphitic carbon composite coating cutting tool also includes first pre-treating the cemented carbide cutting tool and then depositing the nanodiamond layer on the surface of the pre-treated cemented carbide cutting tool; preferably, the pre-treatment includes ultrasonic cleaning; the specific operation of the ultrasonic cleaning is: sequentially ultrasonically clean the cemented carbide cutting tool in an acetone solution, deionized water, and an absolute ethanol solution for 5~20 min respectively.

10. The preparation method of the nano-diamond-like graphite carbon composite coating tool according to claim 6, characterized in that: The preparation method of the nanodiamond-graphitic carbon composite coating cutting tool also includes a step of pre-seeding on the surface of the cemented carbide cutting tool; preferably, the step of pre-seeding includes: placing the cemented carbide cutting tool in a diamond powder suspension for ultrasonic treatment.

11. The preparation method of the nano-diamond-like graphite carbon composite coating tool according to claim 6, characterized in that: In S1, the etching includes plasma etching and / or chemical etching; the plasma etching is carried out in a magnetron sputtering device; preferably, the process parameters of the plasma etching include: the vacuum chamber air pressure range is below 10 -5 Pa, turn on the plasma cleaning source, the Ar gas flow rate is 80~150 sccm, the radio frequency power is 30~80 W, the bias voltage is 80~150 V, and the processing time is 10~30 min.

12. The preparation method of the nano-diamond-like graphite carbon composite coating tool according to claim 6, characterized in that: In S2, the graphitic carbon layer is deposited by physical vapor deposition; preferably, the physical vapor deposition is carried out in a radio frequency magnetron sputtering device, and the specific process parameters include: the graphite target used has a purity of ≥99.99%, the temperature range of the cemented carbide cutting tool during treatment is 150~250°C, the Ar gas flow rate is 10~50 sccm, the target power is 100~200 W, the bias power supply is 0~50 V, the substrate rotation rate is 5~10 rpm, and the deposition time is 1~3 h.

13. The preparation method of the nano-diamond-like graphite carbon composite coating tool according to claim 6, characterized in that: The preparation method of the nano-diamond-like graphite carbon composite coating tool further includes S3: an annealing step; preferably, the specific operation of the annealing includes: placing the cemented carbide tool deposited with the diamond layer and the graphite-like carbon layer in a furnace with an Ar atmosphere, controlling the heating rate to be 1-10 °C / min, the Ar gas flow rate to be 85-100 sccm, the furnace temperature to be 300-400 °C, maintaining for 1-2 h, and then cooling naturally.

14. The preparation method of the nano-diamond-like graphite carbon composite coating tool according to claim 6, wherein: The preparation method of the nano-diamond-like graphite carbon composite coating tool further includes S4: a polishing step; preferably, the specific operation of the polishing includes: polishing the annealed cemented carbide tool using a precision polishing machine, and the polishing materials include diamond spray liquid (particle size 1-10 µm) and a polishing pad; the specific process parameters include: turntable rotation speed: 100-500 rpm, load pressure: 0.5-2 N, time: 5-10 min.

15. Application of a nano-diamond-like graphite carbon composite coating tool in wire bonding of semiconductor packaging, flip-chip bonding and / or hybrid bonding of advanced packaging, cutting of ceramic / glass substrates in precision machining or micro-nano structure machining, characterized in that: The nano-diamond-like graphite carbon composite coating tool includes the nano-diamond-like graphite carbon composite coating tool according to any one of claims 1-5, or is prepared by the preparation method of the nano-diamond-like graphite carbon composite coating tool according to any one of claims 6-14.

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