Method of manufacturing a solid diamond dresser for polishing pads

Abstract

The application provides a manufacturing method of a polishing pad integral diamond dresser, comprising the following steps: S1, processing a disc base; S2, cultivating a large-size CVD diamond sheet; S3, processing the large-size CVD diamond sheet by laser flattening two surfaces of the CVD diamond sheet; S4, obtaining diamond dressing units by laser customized cutting of the large-size CVD diamond sheet; S5, removing a residual graphite layer on the surface of the diamond dressing units; S6, fixing the diamond dressing units in a regular distribution on the disc base; S7, precisely flattening a working surface of the dressing units; S8, processing a micro-cone array structure arranged regularly on the working surface of the dressing units; and S9, detecting index parameters of the dresser. The integral diamond dresser manufactured by the method overcomes all the shortcomings and problems of existing diamond particle type dressers, CVD film type dressers and polycrystalline superhard material type dressers.

Description

Technical Field

[0001] This invention relates to the fields of diamond processing and semiconductor polishing, and particularly to a method for manufacturing an integral diamond dressing device for polishing pads. Background Technology

[0002] Chemical mechanical polishing (CMP) is a key process in semiconductor material surface processing, widely used in surface planarization processes and whole-wafer surface polishing in various stages of integrated circuit (IC) manufacturing. CMP primarily removes material from the surface of semiconductor wafer substrates through the action of polishing pads, polishing slurries, and other chemical reagents. Polishing pads and slurries are the main consumables in the CMP process.

[0003] Polishing pads function to store and transport polishing slurry, remove processing debris, and transfer mechanical loads. The structure and surface roughness of the polishing pad directly determine the material removal rate and surface smoothness of semiconductor wafers during chemical mechanical polishing (CMP). However, after a period of use, abrasive particles in the polishing slurry, along with debris and byproducts generated during polishing, can clog the micropores on the polishing pad surface. This reduces the size and number of micropores, lowers the surface roughness, and gradually forms a glaze layer of a certain thickness. This leads to a decrease in polishing rate and quality, and may even scratch the wafer, resulting in a significantly increased scrap rate. Therefore, proper dressing (also known as "conditioning" or "finishing") of the polishing pad is necessary. This involves a dresser physically penetrating the porous layer on the pad surface to remove the passivated glaze layer and blockages within the micropores, allowing the surface to regenerate and expose new pores. It also creates micro-protrusions on the polishing pad surface, thereby restoring its performance. Although dress-free polishing pads have emerged, many insurmountable technical bottlenecks prevent their widespread application, and the vast majority of polishing pads require timely dressing.

[0004] Polishing pads can be dressed using either a dresser or a brush. A dresser grinds away surface material, increasing surface roughness and thus completely removing the surface glaze and blockages in micropores. However, this inevitably causes some wear and tear on the polishing pad. While a brush does not grind away surface material, it cannot reliably remove accumulated blockages from micropores and has extremely low dressing efficiency. To meet the high-standard processing requirements of semiconductor wafers, the vast majority of polishing pads are currently dressed using dressers.

[0005] Typical polishing pad dressers are generally diamond particle dressers, which use ordered arrangement technology to fix diamond abrasive grains regularly onto a disc-shaped substrate through electroplating, brazing, sintering, etc. For example, patent application number CN202111270275.3 discloses a manufacturing process for a brazed diamond dresser based on cluster units. A specific process is used to use a template to braze individual cluster-shaped dressing units with a single diamond abrasive grain at the top onto the dresser substrate. However, diamond abrasive dressers, especially electroplated ones, pose a risk of abrasive grain shedding during the dressing process, which can easily damage the polishing pad or even scratch the semiconductor wafer. While brazed and sintered dressers offer higher diamond holding power, the high temperatures generated during their manufacturing process can weaken the diamond's strength, making it prone to breakage during dressing. The falling diamond fragments can also scratch the wafer, and the high temperatures can cause substrate deformation. In addition, the varying sizes and shapes of diamond particles result in poor uniformity at the tips (height differences can reach 100μm), reducing the number of effective abrasive grains participating in grinding during dressing, affecting the stability of the dressing process. Some excessively protruding abrasive grains may even penetrate deep into the polishing pad, accelerating pad wear and reducing wafer polishing yield. Furthermore, metal plating, brazing filler metal, and binders may rub or react with the polishing slurry during dressing, which not only negatively impacts the diamond abrasive grain holding power but also introduces metal contamination into the IC wafer, further reducing yield. Therefore, although diamond particle dressers currently dominate the market, they face insurmountable difficulties in areas such as abrasive grain apex height consistency, grain shedding, metal contamination, and abrasive grain edge consistency. With the rapid development of the semiconductor industry, they are increasingly unable to meet the requirements of cost reduction, efficiency improvement, and quality enhancement.

[0006] In recent years, a new type of CVD-coated dresser has emerged. This involves machining a regular square pyramid structure onto a substrate using methods such as shaping grinding, etching, and laser engraving, and then depositing a diamond film onto the surface of the pyramid structure. For example, patent application number CN201611242132.0 discloses a method and equipment for manufacturing a polishing pad dresser. The top of a ceramic ingot is ground to form an array of regular square pyramids with equal-height sharp angles, and then a diamond film is coated onto the tip surface of the ground ceramic ingot to obtain the polishing pad dresser. This new dresser effectively solves the problems of grain removal, metal contamination, and inconsistent abrasive grain shape, and has significant advantages over typical traditional dressers. However, since diamond films are deposited on the surface of the pyramidal structure of the substrate by chemical vapor deposition, there are no bonding bonds at the coating interface. If the deposited film is too thick, not only is the coating interface easy to peel off, but it also causes the pyramids to become blunt, reducing the sharpness of the dresser. At the same time, the non-uniformity of the energy field in the cavity of the deposition equipment leads to inconsistent film thickness on different pyramidal surfaces, affecting the uniformity of height. Therefore, the deposited diamond film is generally thin (about 10~20μm). However, even a thin film inevitably increases the area of ​​the pyramidal apex, which has an adverse effect on the sharpness of the dresser and the dressing and polishing rate. Moreover, the fragile thin film is also easy to wear, shortening the service life of the dresser.

[0007] In addition, there is a very niche type of dressing material based on polycrystalline superhard materials. This involves machining a pyramid shape onto a sintered polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PCBN) sheet using electrical discharge machining (EDM) or diamond grinding wheels, resulting in a one-piece dressing. For example, patent application number CN201811025287.8 discloses a polishing pad dressing and a chemical mechanical planarization (CMP) method. Using non-diamond superhard material PCBN as the abrasive, it directly processes individual cone-shaped pieces, which are then assembled into a CMP polishing pad. This dressing also solves the problems of grain shedding, metal contamination, and inconsistent abrasive grain shape, and it avoids issues such as coating peeling, blunt tops, and poor contour matching. However, PCD and PCBN contain sintering agents or binders, resulting in internal heterogeneity. When subjected to electrical discharge machining or laser processing, they are prone to pores or pits. This not only prevents the cone structure from achieving ideal precision but also reduces the structural strength and wear resistance of the dresser. Furthermore, it makes it easier for debris to adhere during polishing pad dressing, further deteriorating the dresser's performance. Therefore, only diamond grinding wheels can be used for processing, leading to time-consuming, labor-intensive, and excessively costly processing. At the same time, the mechanical properties of polycrystalline superhard materials are inferior to diamond, resulting in lower precision and lifespan for dressers made from polycrystalline superhard materials, ultimately leading to a low overall cost-effectiveness for these dressers.

[0008] Therefore, there is a need to invent an integral diamond dressing tool for polishing pads to overcome all the above problems and achieve the performance requirements of zero granulation, zero breakage, zero peeling, zero contamination, good shape consistency, good height uniformity, high sharpness, high wear resistance, and long service life. Summary of the Invention

[0009] To address the technical problem that existing diamond dresser manufacturing methods cannot meet practical requirements, this invention proposes a method for manufacturing an integral diamond dresser with a polishing pad. The integral diamond dresser manufactured overcomes the shortcomings and problems of existing diamond particle dressers, CVD coated dressers, and polycrystalline superhard material dressers, achieving performance requirements such as zero particle shedding, zero breakage, zero peeling, zero contamination, good shape consistency, good height uniformity, high sharpness, high wear resistance, and long service life.

[0010] To achieve the above objectives, the technical solution of the present invention is implemented as follows: a method for manufacturing an integral diamond dressing device for polishing pads, comprising the following steps:

[0011] S1: Machining the disk substrate;

[0012] S2: Cultivation and growth of a whole CVD diamond sheet;

[0013] S3: Using laser planarization to process the double sides of a CVD diamond sheet, a whole CVD diamond sheet is processed;

[0014] S4: Use laser cutting to cut a whole CVD diamond sheet to obtain a diamond trimming unit;

[0015] S5: Remove residual graphite layer from the surface of the diamond dressing unit;

[0016] S6: Diamond dressing units are regularly distributed and fixedly installed on the disc substrate;

[0017] S7: Perform precision planarization machining on the working surface of the trimming unit;

[0018] S8: Machining of a cone array structure with a particle size of 100~500μm regularly arranged on the working surface of the trimming unit;

[0019] S9: Check the parameters of the trimmer. If the parameters are not met, return to continue processing until the required accuracy is achieved.

[0020] The specific method for processing the disc substrate in step S1 is as follows: Select a stainless steel disc as the substrate, and then process the disc surface using double-end grinding or double-end lapping equipment so that the flatness of both surfaces is no greater than 5μm and the parallelism of the two surfaces is less than 5μm.

[0021] The method for growing a whole CVD diamond wafer in step S2 is as follows: A silicon substrate is placed in the cavity of a chemical vapor deposition (CVD) equipment. A mixed atmosphere of hydrogen and methane is introduced into the cavity of the CVD equipment as a reactant. A high temperature of 1800-2300°C is generated by heating the filament, or plasma generated by a DC arc and microwave is generated, causing the gas in the cavity of the CVD equipment to react, thereby depositing and growing a diamond film on the surface of the silicon substrate in the cavity of the CVD equipment. After the deposition and growth are completed, the diamond self-supporting film is peeled off from the silicon substrate, which is the pure CVD diamond wafer.

[0022] The method for planarizing both sides of a CVD diamond wafer using laser as described in step S3 is as follows:

[0023] S31: Using an infrared nanosecond laser generator, the laser is tilted at a fixed incident angle of 75° to irradiate the surface of a horizontally placed CVD diamond sheet. The height of the laser spot emitting head is adjusted so that the laser is focused at the highest point of the CVD diamond sheet surface.

[0024] S32: Adjust the infrared nanosecond laser generator. Under the action of the two-dimensional galvanometer, make the laser spot scan and irradiate in a circular motion along a straight line or arc in the horizontal direction. At the same time, control the CVD diamond sheet to make a reciprocating linear motion in the horizontal direction. The reciprocating motion direction is perpendicular to the laser spot scanning direction. Through the circular scanning motion of the laser spot and the reciprocating motion of the CVD diamond sheet, the laser spot is evenly distributed on the half of the CVD diamond sheet surface away from the laser spot emitting head.

[0025] S33: After completing one reciprocating linear motion in the horizontal direction, the CVD diamond sheet rotates horizontally around its own center by an angle θ until it has rotated a total of 360°. If the CVD diamond sheet is circular, then θ is 10°; if the CVD diamond sheet is square, then θ is 90°.

[0026] The method for cutting a whole CVD diamond sheet using a laser as described in step S4 is as follows:

[0027] S41: Using an infrared nanosecond laser generator, the laser is used to irradiate the surface of the CVD diamond sheet that has been planarized on both sides and placed vertically to form a laser spot. The height of the laser spot emitting head is adjusted so that the laser is focused on the upper surface of the horizontally placed CVD diamond sheet.

[0028] S42: Control the infrared nanosecond laser generator. Under the action of the two-dimensional galvanometer of the infrared nanosecond laser generator, make the laser spot perform a zigzag-shaped multi-segment parallel straight line trajectory cyclic motion scanning irradiation within the length and width range of the set slit shape in the horizontal direction. The slit width is set to 200μm, and the laser spot is evenly distributed within the set slit range of the horizontally placed CVD diamond sheet.

[0029] S43: As the kerf depth increases, adjust the height of the laser spot emitting head of the infrared nanosecond laser generator so that the laser is always focused on the material surface within the kerf, until the cumulative height adjustment of the laser spot emitting head reaches half the thickness of the CVD diamond sheet after planarization, then fix the height of the laser spot emitting head so that it no longer changes.

[0030] S44: The laser emitted by the infrared nanosecond laser generator continues to irradiate the cutting area until a straight cut is formed that runs through both sides of the CVD diamond sheet.

[0031] S45: Perform laser cutting on the CVD diamond sheet after planarization on both sides according to the set cutting position to obtain several CVD diamond small pieces, which serve as diamond dressing units. The diamond dressing unit includes any one or more of the following dressing units: circular dressing unit, ring dressing unit, square dressing unit, fan-shaped dressing unit, and banana-shaped dressing unit.

[0032] The specific method for removing the residual graphite layer on the surface of the diamond dressing unit in step S5 is as follows: using highly reactive atomic hydrogen or atomic oxygen to etch the residual graphite layer on the planarized surface and cut side of each diamond dressing unit to completely remove the graphite component.

[0033] The specific method for removing the residual graphite layer on the surface of the diamond dressing unit in step S5 is as follows: the graphite layer can also be selectively removed by using free abrasive grinding or grinding wheel grinding.

[0034] The specific method for the diamond dressing units distributed in a fixed regular pattern on the disk substrate in step S6 is as follows: one or more diamond dressing units are fixed to the same disk surface of the disk substrate by adhesive bonding. The planarized surface of the diamond dressing unit is in contact with the disk surface of the substrate. When there is only a single dressing unit, the center of the dressing unit is concentric with the disk substrate. When there are multiple dressing units, the dressing units are distributed in a centrally symmetrical circular array on the disk surface of the disk substrate. When multiple dressing units are not the same shape, the dressing units of different shapes are arranged in a centrally symmetrical circular array without adjacency on the disk surface of the disk substrate.

[0035] The specific method for precision planarization of the working surface of the trimming unit described in step S7 is as follows:

[0036] S71: Place the disk base with the trimming unit fixed horizontally. The back of the trimming unit's mating surface is the working surface of the trimming unit. With the working surface of the trimming unit facing upward, use a picosecond laser generator. The laser beam is irradiated vertically towards the working surface of the trimming unit to form a laser spot. Adjust the height of the laser spot emitting head so that the laser is focused at the highest area of ​​all the working surfaces of the trimming units.

[0037] S72: Based on the position, spacing, shape and size of each trimming unit, set a processing pattern that is consistent with the size, shape and distribution of the trimming unit. Control the picosecond laser generator so that the laser spot moves and scans in a zigzag pattern along the horizontal direction on the working surface of each trimming unit under the action of the two-dimensional galvanometer, so that the laser spot is evenly distributed on the working surface of all trimming units.

[0038] S73: Adjust the height of the laser spot emitter to keep the laser spot focused in the highest area of ​​all trimming unit working surfaces. Repeat S72 until the flatness of all trimming unit working surfaces is less than 5μm and the height difference of trimming units is less than 5μm.

[0039] The manufacturing method of the integral diamond dressing device for the polishing pad according to claim 9 is characterized in that the specific method for processing the regularly arranged micro-cone array structure on the working surface of the dressing unit in step S8 is as follows:

[0040] S81: The entire disc base with the trimming unit fixed and the working surface flattened is mounted on the positioning fixture, with the disc base placed horizontally and the working surface of the trimming unit facing upward.

[0041] S82: An ultrafast pulse femtosecond laser generator is used to irradiate the working surface of the trimming unit with a laser beam perpendicularly, forming a laser spot. The height of the laser spot emitting head is adjusted to focus the laser on the working surface of the trimming unit.

[0042] S83: Based on the position, spacing, shape and size of each trimming unit, set a basic processing graphic that is consistent with the size, shape and distribution of the trimming unit, and delineate the working surface of all trimming units as the laser irradiation processing area;

[0043] S84: Set one or more structural processing graphics for processing micro cones within the basic processing graphics. The shapes of the structural processing graphics are gradually increasing in size and the dimensions are equal. Each group of structural processing graphics contains the same number of circular or polygonal arrays with the same shape, the same center position, the same regular arrangement, and different sizes. Each group of processing areas covers all trimming units at the same time, and the processing areas of each group are sorted in chronological order.

[0044] S85: Using a femtosecond laser generator, the laser spot is sequentially scanned and irradiated in a zigzag pattern along the horizontal direction in each enclosed processing area, so that the laser spot is evenly distributed in each enclosed processing area. This enables simultaneous, layer-by-layer, equal-interval, step-by-step processing on all trimming unit working surfaces from top to bottom, resulting in trimming units with an integral microcone array structure.

[0045] S86: After completing the above steps, increase the scanning direction of the laser spot by 90°, and switch the scanning direction angle cumulatively. Repeat steps S82-S85 until the microcone array structure on all trimming unit working surfaces meets the actual index requirements.

[0046] The beneficial effects of the present invention are as follows: (1) The present invention provides a method for manufacturing an integral diamond dresser for polishing pads, and innovatively manufactures a new type of dresser that is different from existing diamond particle dressers, CVD coating dressers, and polycrystalline superhard material dressers. It overcomes all the shortcomings and problems of existing dressers such as granulation, breakage, peeling, contamination, poor height matching, and short lifespan, and achieves excellent performance.

[0047] (2) The integral diamond dressing device of the present invention contains an integral diamond dressing unit with pure composition and uniform texture. It does not damage the diamond structure during manufacturing and processing. Moreover, the diamond has excellent physical and mechanical properties and chemical stability, which can meet the use requirements of zero granulation, zero breakage, zero peeling and zero pollution of the dressing device.

[0048] (3) The dressing unit and its micro-cone structure of the integral diamond dressing tool of the present invention can achieve extremely high processing accuracy, and have very consistent and regular shape, arrangement, height, sharp corner and other characteristics. It can also realize adjustable and controllable customized and personalized manufacturing, and meet the usage requirements of the dressing tool with good height uniformity of the protrusion, good shape consistency and high sharpness.

[0049] (4) The dressing unit of the integral diamond dressing device of the present invention is made of diamond material, which has extremely strong wear resistance. Moreover, after passivation, it can be returned to processing and repair for repeated use, which can meet the needs of dressing device with high wear resistance and long service life.

[0050] (5) This invention has innovatively developed a complete set of technologies for laser planarization, laser cutting, and laser processing of microconical structures for CVD diamond, providing new ideas and methods for diamond dressing tools and other new diamond tools. Attached Figure Description

[0051] 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, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic diagram of the method flow of the present invention.

[0053] Figure 2This is a schematic diagram of the laser planarization processing method of the present invention.

[0054] Figure 3 This is a schematic diagram showing the effects of laser planarization before and after processing according to the present invention.

[0055] Figure 4 This is a schematic diagram of the slit location and the laser spot scanning trajectory within the slit range of the present invention.

[0056] Figure 5 This is a schematic diagram of the laser spot scanning trajectory for the precision planarization process of the trimming unit of the present invention.

[0057] Figure 6 This is a schematic diagram of the laser spot scanning trajectory of the first set of processing areas in this invention.

[0058] Figure 7 This is a schematic diagram of the laser spot scanning trajectory in the intermediate processing area of ​​the present invention.

[0059] Figure 8 This is a schematic diagram of the laser spot scanning trajectory in the final processing area of ​​the present invention.

[0060] Figure 9 The pyramid microstructure is processed on the trimming unit of the present invention.

[0061] In the figure, 1 is the whole CVD diamond sheet, 2 is the laser spot emitting head, 3 is the laser spot motion trajectory during double-sided planarization, 4 is the laser beam, 5 is the kerf and the laser spot motion trajectory within the kerf, 6 is the diamond dressing unit obtained by cutting, 7 is the disk substrate, 8 is the dressing unit and its laser spot motion trajectory during precision planarization, 9 is the laser spot motion trajectory of the first group of processing areas, 10 is the laser spot motion trajectory of the middle group of processing areas, and 11 is the laser spot motion trajectory of the last group of processing areas. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] like Figure 1 As shown, a method for manufacturing an integral diamond dressing device for polishing pads is characterized by comprising the following steps:

[0064] S1: Select a disk made of corrosion-resistant high-hardness alloy or ceramic material as the substrate. The disk diameter is 120mm and the thickness is 10mm. Then, process the disk surface using double-end grinding or double-end lapping equipment to ensure that the flatness of both sides is no greater than 5μm and the parallelism of the two sides is less than 5μm.

[0065] S2: Cultivating and growing a whole CVD diamond sheet 1, the specific method is as follows:

[0066] In a chemical vapor deposition (CVD) apparatus, a mixture of hydrogen and methane is introduced into the chamber as the reactants. The reactants are activated by a high temperature of 1800–2300°C generated by a heating filament, or by plasma generated by a DC arc or microwaves. This activates the gas-phase chemical reaction within the chamber, depositing a diamond film onto the silicon substrate. The silicon substrate is circular, with an area not less than that of a disk substrate. The deposited diamond film is thicker than 300 μm. It is important to note that significant differences in deposition rates across different regions can lead to poor surface accuracy and large thickness deviations in the deposited diamond film; therefore, the thinnest region of the deposited diamond film must be at least 300 μm thick. After deposition, the silicon substrate is dissolved in a strong acid to obtain a self-supported diamond film, i.e., a pure CVD diamond wafer, which is then peeled off from the substrate.

[0067] S3: Using laser planarization to process both sides of the CVD diamond wafer, a complete CVD diamond wafer 1 is fabricated, such as... Figure 2 As shown, the specific method is as follows:

[0068] S31: Using an infrared nanosecond laser generator, the emitted laser beam passes through a beam expander and a reflecting prism, and then through a two-dimensional galvanometer and a focusing lens, and is tilted at a fixed incident angle of 75° to irradiate the surface of a horizontally placed CVD diamond sheet, forming a laser spot. The height of the laser spot emitting head 2 is adjusted so that the laser is focused at the highest point of the CVD diamond sheet surface.

[0069] S32: Adjust the infrared nanosecond laser generator so that, under the action of the two-dimensional galvanometer, the laser spot can perform cyclic scanning irradiation along a straight line or arc in the horizontal direction. At the same time, control the CVD diamond sheet to perform reciprocating linear motion in the horizontal direction. The reciprocating motion direction is perpendicular to the laser spot's scanning direction. Through the cyclic scanning motion of the laser spot and the reciprocating motion of the CVD diamond sheet, the laser spot is evenly distributed on half of the CVD diamond sheet surface away from the laser spot emitting head 2.

[0070] S33: After completing one reciprocating linear motion in the horizontal direction, the CVD diamond sheet rotates by 10° until it has rotated a total of 360°, so that the laser spot is evenly distributed over the entire upper surface of the horizontally placed CVD diamond sheet, and is only distributed on the upper surface.

[0071] The uniformly distributed laser beam and the oblique incidence of the laser beam amplify the difference in laser defocusing between high and low points on the CVD diamond wafer surface. High points have smaller defocusing and stronger focusing energy, while low points have larger defocusing and weaker focusing energy. This allows for automatic distribution of laser energy across the CVD diamond wafer surface, resulting in more material removal at high points and less at low points, ultimately achieving laser planarization of the entire CVD diamond wafer surface. Each processing pass consists of a cumulative 360° rotation of the CVD diamond wafer. The number of laser planarization passes can be adjusted based on the real-time surface shape during processing, and the height of the laser beam emitter 2 can be adjusted according to the amount of material removed from high points on the CVD diamond wafer surface, ensuring that the laser maintains the strongest focusing energy in the highest region of the CVD diamond wafer surface.

[0072] Using the same laser planarization method described above, both sides of the CVD diamond wafer were processed until the overall flatness of both sides was less than 10 μm and the overall thickness deviation of the CVD diamond wafer was less than 5 μm. A schematic diagram of the effects before and after laser planarization is shown below. Figure 3 As shown.

[0073] S4: Using laser-customized cutting of the entire CVD diamond sheet 1, diamond trimming units are obtained. The specific steps are as follows:

[0074] S41: The laser beam emitted by the infrared nanosecond laser generator passes through the beam expander and the reflecting prism, and then through the two-dimensional galvanometer and the focusing lens. It is then irradiated vertically at an incident angle of 0° onto the surface of the horizontally placed CVD diamond sheet after planarization, forming a laser spot. The height of the laser spot emitting head 2 is adjusted so that the laser is focused on the upper surface of the horizontally placed CVD diamond sheet.

[0075] S42: Controls the infrared nanosecond laser generator. Under the action of the two-dimensional galvanometer, the laser spot performs a zigzag-shaped multi-segment parallel straight line cyclic motion scanning irradiation within the length and width range of the set slit shape in the horizontal direction. The slit width is set to 200μm, and the laser spot is evenly distributed within the set slit range of the horizontally placed CVD diamond sheet.

[0076] S43: As the kerf depth increases, adjust the height of the laser spot emitter head to keep the laser focused on the material surface within the kerf until the cumulative adjustment height of the laser spot emitter head reaches half the thickness of the CVD diamond sheet after planarization. Then fix the height of the laser spot emitter head 2 so that the focal plane of the laser focus is located at the middle position of the CVD diamond sheet thickness.

[0077] S44: The laser emitted by the infrared nanosecond laser generator continues to irradiate the cut area until a straight cut is formed that runs through both sides of the CVD diamond sheet.

[0078] S45: Laser cutting is performed on the CVD diamond sheet after planarization on both sides according to the set cutting position to obtain several CVD diamond small pieces, which serve as diamond dressing units. The diamond dressing units include circular dressing units and square dressing units.

[0079] like Figure 4 As shown, the cutting positions of two adjacent diamond trimming units on a CVD diamond wafer should be as close as possible to improve the utilization rate of diamond material and avoid the edge region of the CVD diamond wafer to eliminate possible crystal growth or processing defects in the edge region. Six diamond trimming units are cut from a CVD diamond wafer: three are circular trimming units and three are square trimming units, with the diameter and side length not exceeding half the diameter of the disk substrate 7.

[0080] S5: Removing residual graphite layer from the surface of the diamond dressing unit. Infrared nanosecond lasers have high power and energy, making them suitable for efficient planarization and cutting processes involving large quantities of material. However, the diamond processing process generates heat and can cause graphitization, leaving a residual graphite layer. Specifically, highly reactive atomic hydrogen or oxygen can be used to selectively etch the residual graphite layer on the planarized surface and cut sides of each diamond dressing unit, completely removing the graphite component without damaging the diamond. Alternatively, free abrasive grinding or grinding wheel milling can be used to selectively remove the graphite layer. For free abrasives, fine-grained ordinary abrasives or superhard CBN abrasives can be selected. For grinding wheels, fine-grained ordinary abrasive wheels or superhard CBN grinding wheels can be selected. The abrasive grit size is generally W40 or finer.

[0081] S6: Diamond dressing units are fixed in a regular distribution on the disk substrate 7. Each diamond dressing unit is fixed to the same disk surface of the disk substrate 7 by adhesive bonding. The planarized surface of the diamond dressing unit is in contact with the disk surface of the substrate. Three circular dressing units and three square dressing units are arranged in a regular alternating circular array in a centrally symmetrical manner on the disk surface of the disk substrate 7.

[0082] S7: Perform precision flattening on the working surface of the trimming unit to eliminate minor unevenness introduced during the bonding and fixing of the trimming unit. The specific method is as follows:

[0083] S71: The disc substrate 7 with the trimming units fixed is placed horizontally, with the back side of the trimming unit's mating surface serving as the working surface. The working surface of the trimming unit faces upwards. A picosecond laser generator is used to irradiate the working surface of the trimming unit at a 0° incident angle, forming a laser spot. The height of the laser spot emitting head 2 is adjusted so that the laser is focused on the highest area of ​​all the working surfaces of the trimming units. Short-wavelength picosecond laser processing generates very little heat, making it a cold processing method suitable for precision machining. Furthermore, the picosecond laser has a small Rayleigh length and a very short depth of focus. The small height difference between the high and low points on the working surface of the trimming unit exhibits a significant difference in focusing energy; the high point area has strong focusing energy, while the low point area has weak focusing energy, thus achieving more removal at high points and less removal at low points.

[0084] S72: Based on the position, spacing, shape and size of each trimming unit, set a processing pattern that is consistent with the size, shape and distribution of the trimming unit. Control the picosecond laser generator so that the laser spot moves in a zigzag pattern along the horizontal direction to scan and irradiate the working surface of each trimming unit in the action of the two-dimensional galvanometer. The area outside the working surface of the trimming unit is not irradiated, so that the laser spot is evenly distributed on the working surface of all trimming units.

[0085] S73: As Figure 5 As shown, each processing pass consists of one complete scan of the working surface of all trimming units by the laser spot. The number of processing passes can be adjusted based on the real-time surface shape results during the processing of the trimming unit's working surface. The height of the laser spot emitter 2 is also adjusted according to the amount of material removed from the high points of the trimming unit's working surface, ensuring that the laser maintains the strongest focused energy in the highest area of ​​all trimming unit's working surfaces. Step S72 is repeated until the goal of all trimming unit's working surfaces being flat and at the same height is achieved. The flatness of each trimming unit's working surface is less than 5μm; with the blank disk surface of the disk substrate 7 as the reference surface, the height difference of all trimming units is less than 5μm.

[0086] S8: Machining of the regularly arranged micro-cone array structure on the working surface of the trimming unit, the specific method is as follows:

[0087] S81: The disc base 7, with its dressing unit fixed and its working surface precisely planarized, is mounted as a whole on a precision positioning fixture. The disc base 7 is placed horizontally with the working surface of the dressing unit facing upwards. The structure of the precision positioning fixture is not limited; it can be a jaw-locking type, a slot-engaging type, etc. The precision positioning fixture ensures the repeatability of the positioning accuracy when the disc base 7 is reinstalled, allowing the integral diamond dresser to be used again for the machining of the micro-cone structure on the working surface after passivation, thus realizing the repair and reuse of the dresser.

[0088] S82: Employs an ultrafast pulse femtosecond laser generator. The emitted laser beam passes through a beam expander and a reflecting prism, then through a two-dimensional galvanometer and a focusing lens, and finally irradiates the working surface of the trimming unit at a 0° incident angle, forming a laser spot. The height of the laser spot emitting head 2 is adjusted to focus the laser onto the working surface of the trimming unit. Each trimming unit working surface, after precision planarization, is not only flat but also has excellent height uniformity, all located on the focal plane after laser focusing.

[0089] S83: Based on the position, spacing, shape and size of each trimming unit, set a basic processing graphic that is consistent with the size, shape and distribution of the trimming unit, and delineate the working surface of all trimming units as the laser irradiation processing area;

[0090] S84: Set one or more structural processing graphics for processing micro cones within the basic processing graphics. The shapes of the structural processing graphics are gradually increasing in size and the dimensions are equal. Each group of structural processing graphics contains the same number of circular or polygonal arrays with the same shape, the same center position, the same regular arrangement, and different sizes. Each group of processing areas covers all trimming units at the same time, and the processing areas of each group are sorted in chronological order.

[0091] S85: Using a femtosecond laser generator, the laser spot is sequentially scanned and irradiated in a zigzag pattern along the horizontal direction in each enclosed processing area, so that the laser spot is evenly distributed in each enclosed processing area. This enables simultaneous, layer-by-layer, equal-interval, step-by-step processing on all trimming unit working surfaces from top to bottom, resulting in trimming units with an integral microcone array structure.

[0092] S86: After completing the above steps, increase the scanning direction of the laser spot by 90°, and switch the scanning direction angle cumulatively. Repeat steps S82-S85 until the microcone array structure on all the working surfaces of the trimming units meets the actual performance requirements. The laser spot scanning trajectory of the first processing area is as follows: Figure 6 As shown, the laser spot scanning trajectory in the intermediate processing area is as follows: Figure 7 As shown, the laser spot scanning trajectory of the final processing area is as follows: Figure 8 As shown.

[0093] Ultrafast pulsed femtosecond laser processing generates no heat and leaves no damaged layer on the diamond surface, making it suitable for high-precision microstructure machining. The type of microcone can be controlled by regularly arranged circular or polygonal arrays within the structure processing pattern. Circular arrays produce edgeless conical microstructures, square arrays produce pyramidal microstructures with four edges, and triangular arrays produce triangular pyramidal microstructures with three edges. Custom polygonal arrays can also be used to produce custom microconical structures with corresponding multiple edges. Results are shown below. Figure 9As shown, the top surface size of the microcone is controlled by the first set of structural processing patterns with the smallest size, and the side length or diameter is generally 10~50μm; the bottom surface size of the microcone is set by the last set of structural processing patterns with the largest size, and the side length or diameter is generally 400~800μm; the height of the microcone is controlled by the number of processing passes, and is generally 100~300μm.

[0094] S9: After completing the micro-cone array structure processing on all the working surfaces of the dressing unit, an integral diamond dresser is obtained. The height, top surface size, bottom surface size, spacing, and other parameters of each cone on the dresser are observed using a laser microscope. The height consistency, shape consistency, and arrangement consistency of all cones of the same specification on the dresser are evaluated. If the index requirements are not met, the process is returned to continue until the index accuracy is achieved.

[0095] This invention focuses on the laser processing of CVD diamond, fully considering the ultimate uniformity of the top of the protrusions on the dresser surface, absolute zero granulation and zero contamination, stable and efficient material removal rate, and excellent service life. It performs surface planarization processing, specific shape cutting processing, and regular conical microstructure processing on a whole CVD diamond sheet to manufacture an integral diamond dresser with a single component and homogeneous material. This achieves the performance requirements of zero granulation, zero breakage, zero peeling, zero contamination, good shape consistency, good uniformity, high sharpness, high wear resistance, and long service life.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing an integral diamond dressing device with a polishing pad, characterized in that, Includes the following steps: S1: Process the disk substrate (7); S2: Cultivation and growth of whole CVD diamond sheets (1); S3: Use laser planarization to process the double sides of the CVD diamond sheet to process the whole CVD diamond sheet (1). S4: Use laser cutting to cut a whole CVD diamond sheet (1) to obtain a diamond trimming unit; S5: Remove residual graphite layer from the surface of the diamond dressing unit; S6: A regularly distributed diamond dressing unit is fixedly installed on the disc substrate (7); S7: Perform precision planarization machining on the working surface of the trimming unit; S8: Processing of micro-cone array structures with particle sizes of 100~500μm regularly arranged on the working surface of the trimming unit; S9: Check the parameters of the trimmer. If the parameters do not meet the requirements, return to the machine for further processing until the required accuracy is achieved. The specific method for processing the regularly arranged micro-cone array structure on the working surface of the trimming unit in step S8 is as follows: S81: The disc base (7) with the trimming unit fixed and the working surface flattened is installed on the positioning fixture as a whole. The disc base (7) is placed horizontally with the working surface of the trimming unit facing upward. S82: An ultrafast pulse femtosecond laser generator is used to irradiate the laser beam perpendicularly to the working surface of the trimming unit, forming a laser spot. The height of the laser spot emitting head (2) is adjusted so that the laser is focused on the working surface of the trimming unit. S83: Based on the position, spacing, shape and size of each trimming unit, set a basic processing graphic that is consistent with the size, shape and distribution of the trimming unit, and delineate the working surface of all trimming units as the laser irradiation processing area; S84: Set one or more structural processing graphics for processing micro cones within the basic processing graphics. The shape of the structural processing graphics gradually changes from small to large with equal amplitude. Each group of structural processing graphics is compared with each other. Each group contains the same number of circular or polygonal arrays with the same shape, the same center position, the same regular arrangement, and different sizes. Each group of processing areas covers all trimming units at the same time, and the processing areas of each group are sorted in order. S85: Using a femtosecond laser generator, the laser spot is sequentially scanned and irradiated in a zigzag pattern along the horizontal direction in each enclosed processing area, so that the laser spot is evenly distributed in each enclosed processing area. This enables simultaneous, layer-by-layer, equal-interval, step-by-step processing on all trimming unit working surfaces from top to bottom, resulting in trimming units with an integral microcone array structure. S86: Increase the scanning direction of the laser spot by 90°, and switch the scanning direction angle cumulatively. Repeat steps S82-S85 until the microcone array structure on all trimming unit working surfaces meets the actual performance requirements.

2. The method for manufacturing the integral diamond dressing device for the polishing pad according to claim 1, characterized in that, The specific method for processing the disc substrate (7) in step S1 is as follows: select a stainless steel disc as the substrate, and then process the disc surface using double-end grinding or double-end polishing equipment so that the flatness of both surfaces is no greater than 5μm and the parallelism of both surfaces is less than 5μm.

3. The method for manufacturing the integral diamond dressing device for the polishing pad according to claim 2, characterized in that, The method for growing a whole CVD diamond wafer (1) described in step S2 is as follows: a silicon substrate is placed in the cavity of a chemical vapor deposition equipment, and a mixed atmosphere of hydrogen and methane is introduced into the cavity of the chemical vapor deposition equipment as a reactant. A high temperature of 1800-2300℃ is generated by heating the filament or plasma generated by DC arc and microwave, so that the gas in the cavity of the chemical vapor deposition equipment reacts, thereby depositing and growing a diamond film on the surface of the silicon substrate in the cavity of the chemical vapor deposition equipment. After the deposition and growth are completed, the diamond self-supporting film is peeled off from the silicon substrate, which is the pure CVD diamond wafer.

4. The method for manufacturing an integral diamond dressing device for a polishing pad according to claim 3, characterized in that, The method for planarizing both sides of a CVD diamond wafer using laser as described in step S3 is as follows: S31: Using an infrared nanosecond laser generator, the laser is tilted at a fixed incident angle of 75° to irradiate the surface of the horizontally placed CVD diamond sheet. The height of the laser spot emitting head (2) is adjusted so that the laser is focused at the highest point of the CVD diamond sheet surface. S32: Adjust the infrared nanosecond laser generator, and under the action of the two-dimensional galvanometer, make the laser spot perform cyclic scanning irradiation along a straight line or arc in the horizontal direction. At the same time, control the CVD diamond sheet to perform reciprocating linear motion in the horizontal direction. The reciprocating motion direction is perpendicular to the laser spot motion scanning direction. Through the cyclic scanning of the laser spot and the reciprocating motion of the CVD diamond sheet, the laser spot is evenly distributed on half of the CVD diamond sheet surface away from the laser spot emitting head (2). S33: After completing one reciprocating linear motion in the horizontal direction, the CVD diamond sheet rotates horizontally around its own center by an angle θ until it has rotated a total of 360°. If the CVD diamond sheet is circular, then θ is 10°; if the CVD diamond sheet is square, then θ is 90°.

5. A method for manufacturing an integral diamond dressing device for a polishing pad according to any one of claims 2-4, characterized in that, The method for cutting a whole CVD diamond sheet (1) using a laser as described in step S4 is as follows: S41: Using an infrared nanosecond laser generator, the laser is used to irradiate the surface of the CVD diamond sheet after it has been planarized on both sides and placed vertically to form a laser spot. The height of the laser spot emitting head (2) is adjusted so that the laser is focused on the upper surface of the horizontally placed CVD diamond sheet. S42: Control the infrared nanosecond laser generator. Under the action of the two-dimensional galvanometer of the infrared nanosecond laser generator, make the laser spot perform a zigzag-shaped multi-segment parallel straight line trajectory cyclic motion scanning irradiation within the length and width range of the set slit shape in the horizontal direction. The slit width is set to 200μm, and the laser spot is evenly distributed within the set slit range of the horizontally placed CVD diamond sheet. S43: As the kerf depth increases, adjust the height of the laser spot emitting head of the infrared nanosecond laser generator so that the laser is always focused on the material surface inside the kerf until the cumulative height adjustment of the laser spot emitting head reaches half the thickness of the CVD diamond sheet after planarization. Then fix the height of the laser spot emitting head (2) so that it no longer changes. S44: The laser emitted by the infrared nanosecond laser generator continues to irradiate the cutting area until a straight cut is formed that runs through both sides of the CVD diamond sheet. S45: Perform laser cutting on the CVD diamond sheet after planarization on both sides according to the set cutting position to obtain several CVD diamond small pieces, which serve as diamond dressing units. The diamond dressing unit includes any one or more of the following dressing units: circular dressing unit, ring dressing unit, square dressing unit, fan-shaped dressing unit, and banana-shaped dressing unit.

6. The method for manufacturing an integral diamond dressing device for a polishing pad according to claim 5, characterized in that, The specific method for removing the residual graphite layer on the surface of the diamond dressing unit in step S5 is as follows: using highly reactive atomic hydrogen or atomic oxygen to etch the residual graphite layer on the planarized surface and cut side of each diamond dressing unit to completely remove the graphite component.

7. The method for manufacturing an integral diamond dressing device for a polishing pad according to claim 5, characterized in that, The specific method for removing the residual graphite layer on the surface of the diamond dressing unit in step S5 is as follows: the graphite layer can also be selectively removed by using free abrasive grinding or grinding wheel grinding.

8. The method for manufacturing an integral diamond dressing device for a polishing pad according to claim 6 or 7, characterized in that, The specific method for the diamond dressing units distributed in a fixed regular pattern on the disk substrate (7) in step S6 is as follows: one or more diamond dressing units are fixed on the same disk surface of the disk substrate (7) by adhesive bonding. The planarized surface of the diamond dressing unit is attached to the disk surface of the substrate. When there is only a single dressing unit, the center of the dressing unit is concentric with the disk substrate. When there are multiple dressing units, the dressing units are distributed in a centrally symmetrical circular array on the disk surface of the disk substrate. When multiple dressing units are not the same shape, the dressing units of different shapes are arranged in a centrally symmetrical circular array without adjacency on the disk surface of the disk substrate.

9. The method for manufacturing an integral diamond dressing device for a polishing pad according to claim 8, characterized in that, The specific method for precision planarization of the working surface of the trimming unit described in step S7 is as follows: S71: Place the disk substrate (7) with the trimming unit fixed horizontally. The back of the trimming unit's mating surface is the working surface of the trimming unit. With the working surface of the trimming unit facing upward, use a picosecond laser generator. The laser beam is vertically irradiated onto the working surface of the trimming unit to form a laser spot. Adjust the height of the laser spot emitting head (2) so that the laser is focused on the highest area of ​​all the working surfaces of the trimming units. S72: Based on the position, spacing, shape and size of each trimming unit, set a processing pattern that is consistent with the size, shape and distribution of the trimming unit. Control the picosecond laser generator so that the laser spot moves and scans in a zigzag pattern along the horizontal direction under the action of the two-dimensional galvanometer, so that the laser spot is evenly distributed on the working surface of all trimming units. S73: Adjust the height of the laser spot emitter to keep the laser spot focused in the highest area of ​​all trimming unit working surfaces. Repeat S72 until the flatness of all trimming unit working surfaces is less than 5μm and the height difference of trimming units is less than 5μm.

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