Surface processing apparatus and surface processing method for cutting blade

Abstract

This application discloses a surface processing device and method for a cutting disc, comprising: a machine body having a processing station for supporting the cutting disc to be processed; a composite polishing pad disposed opposite to the processing station, including a polishing pad base and an abrasive layer disposed on one side surface of the polishing pad base; a first liquid supply system for supplying a water-based additive to the processing station; a second liquid supply system for supplying polishing fluid to the processing station; and a controller for controlling the working state of the first and second liquid supply systems based on the thinning thickness of the cutting disc to be processed after the processing equipment is started; when the thinning thickness is less than a set target value, the second liquid supply system is controlled to close and the first liquid supply system is controlled to open; when the thinning thickness is not less than the set target value and the abrasive layer of the composite polishing pad is completely removed, the first liquid supply system is controlled to close and the second liquid supply system is controlled to open, so as to sequentially perform surface thinning treatment and surface polishing treatment on the cutting disc to be processed.

Description

Technical Field

[0001] This application relates to the field of semiconductor substrate processing technology, and in particular to a surface processing device and method for cutting wafers. Background Technology

[0002] After wire cutting, semiconductor wafers (such as silicon carbide wafers, silicon wafers, sapphire wafers, etc.) usually have saw marks, scratches and a certain thickness of damage layer on their surface. Subsequent grinding and polishing processes are required to remove the damage layer and improve the surface quality in order to obtain a substrate or base material that meets the requirements of subsequent processes.

[0003] Currently, the subsequent processing of semiconductor wafers mainly employs a multi-step, separate processing technology. Taking silicon carbide wafers as an example, a typical process is as follows: First, coarse grinding is performed on a cast iron disc using single-crystal diamond polishing slurry to quickly remove saw marks and surface damage layers introduced by wire cutting; then, fine grinding is performed using a different equipment and polishing slurry to further reduce surface roughness and improve the surface profile; afterwards, the wafers are transferred to a chemical mechanical polishing (CMP) machine, where coarse and fine polishing slurries are used sequentially for rough and fine polishing. During this process, the wafers typically require thorough cleaning and drying between the grinding and polishing steps to avoid cross-contamination between abrasive particles of different sizes. Each step is completed on different processing equipment, and each step requires equipment debugging, polishing pad preparation, and process parameter setting.

[0004] However, the above-mentioned existing processing methods have the following shortcomings: Firstly, the processing efficiency is low. It involves multiple independent processes such as rough grinding, fine grinding, rough polishing, and fine polishing. Each process requires independent machine preparation and processing time. In addition, the transfer, cleaning, and drying of cutting discs between processes are time-consuming, resulting in a long overall processing cycle, which seriously restricts production efficiency and makes it difficult to meet the needs of large-scale mass production.

[0005] Secondly, the processing costs are high. Multiple processes require various types of processing equipment, resulting in high investment and maintenance costs. Furthermore, each process consumes large quantities of consumables such as grinding fluid, polishing fluid, and polishing pads, with particularly severe equipment wear and abrasive consumption during the rough grinding and rough polishing stages, further increasing production costs. In addition, the repeated transfer of cutting discs between multiple processes also increases manual operation costs.

[0006] Third, surface quality and reliability are difficult to guarantee. During the rough and fine grinding stages, the use of hard abrasives such as diamond for mechanical removal easily introduces deep scratches and subsurface damage layers onto the cutting disc surface. If subsequent polishing processes cannot completely remove these damages, it will directly affect the performance and yield of the final product. Simultaneously, during the transfer of the cutting disc between multiple machines, the edges are prone to chipping or secondary contamination, leading to an increased product scrap rate.

[0007] Fourth, controlling thickness uniformity is difficult. The cutting disc needs to be clamped and positioned multiple times in multiple processes. The equipment precision and processing parameters of each process are difficult to match perfectly, which easily leads to the accumulation of positioning errors and processing deviations, resulting in large fluctuations in the total thickness and warpage of the final product.

[0008] To address the aforementioned issues, while some existing technologies have attempted to improve the processing results of single steps by optimizing the polishing slurry formulation or polishing pad material, these improvements only target a single step and fail to fundamentally solve the inherent problems of low efficiency, high cost, cross-contamination between steps, and cumulative errors in multi-step, separate processing flows. These problems are particularly pronounced for difficult-to-machine materials like silicon carbide, which are characterized by high hardness and brittleness.

[0009] Therefore, there is an urgent need in this field for an integrated processing solution that can combine the thinning and polishing of the cutting discs into the same equipment and the same workstation, in order to simplify the process flow, shorten the processing cycle, reduce costs, and at the same time improve the surface quality and thickness uniformity of the cutting discs. Summary of the Invention

[0010] In view of the above problems, this application provides a surface processing device and a surface processing method for cutting discs, the specific solution of which is as follows: The first aspect of this application provides a surface processing apparatus for a cutting disc, comprising: The main body of the machine tool has a processing station for holding the cutting disc to be processed; A composite polishing pad is arranged opposite to the processing station. The composite polishing pad includes a polishing pad base and an abrasive layer disposed on one side surface of the polishing pad base. The first liquid supply system is used to supply water-based additives to the processing station; The second liquid supply system is used to supply polishing liquid to the processing station; The controller controls the operation of the first and second liquid supply systems based on the thinning thickness of the cutting disc to be processed after the processing equipment is started. When the thinning thickness is less than the set target value, the controller shuts down the second liquid supply system and turns on the first liquid supply system to provide water-based additives to the processing station for surface thinning treatment of the cutting disc to be processed. When the thinning thickness is not less than the set target value and the abrasive layer of the composite polishing pad is completely removed, the controller shuts down the first liquid supply system and turns on the second liquid supply system to provide polishing fluid to the processing station for surface polishing treatment of the cutting disc to be processed.

[0011] Optionally, in the above-mentioned surface processing equipment, the main body of the machine includes an upper polishing disc and a lower polishing disc arranged opposite to each other; each of the upper polishing disc and the lower polishing disc is fixed with a composite polishing pad, the abrasive layers of the two composite polishing pads are arranged opposite to each other, and the processing station is located between the two composite polishing pads; The main body of the machine also includes a lifting drive mechanism, which is connected to at least one of the upper polishing disc and the lower polishing disc, and is used to control the vertical height of at least one of the upper polishing disc and the lower polishing disc.

[0012] Optionally, the surface processing equipment described above further includes: A thickness detection device is used to detect the thinning thickness of the cutting disc to be processed.

[0013] Optionally, in the above-mentioned surface processing equipment, the thickness detection device is based on a non-contact laser interferometry method, which uniformly selects multiple monitoring points on the surface of the cut sheet to be processed for thickness measurement.

[0014] Optionally, in the above-mentioned surface processing equipment, the abrasive in the abrasive layer includes at least two different types of abrasive grains with different particle sizes.

[0015] Optionally, in the above-mentioned surface processing equipment, the polishing fluid includes silica gel abrasive particles, the particle size of which is smaller than the particle size of at least one abrasive particle in the abrasive layer.

[0016] Optionally, in the above-mentioned surface processing equipment, the abrasive particles in the abrasive layer include agglomerated diamond micro powder and alumina particles; Among them, the mass proportion of agglomerated diamond micro powder is greater than that of alumina particles, and the particle size of agglomerated diamond micro powder is greater than that of alumina particles.

[0017] Optionally, in the above-mentioned surface processing equipment, the mass ratio of agglomerated diamond micro powder to alumina particles is 3:2; The particle size of agglomerated diamond micropowder is 5μm ~ 10μm; The particle size of alumina particles is 0.1 μm to 1 μm.

[0018] Optionally, in the above-mentioned surface processing equipment, the polishing pad substrate has a first grid groove on the side facing the abrasive layer; the composite polishing pad also includes a plurality of ventilation holes penetrating the polishing pad substrate.

[0019] The surface of the abrasive layer has a second grid groove.

[0020] A second aspect of this application provides a surface processing method for a cutting disc, comprising: The cutting disc to be processed is placed on the processing station in the above-mentioned surface processing equipment, and the surface of the cutting disc to be processed is performed. During the surface processing of the cutting disc, the thinning thickness of the cutting disc is monitored in real time. Based on the thinning thickness, the working states of the first and second liquid supply systems are controlled. Specifically, when the thinning thickness of the cut sheet to be processed is less than the set target value, the second liquid supply system is turned off and the first liquid supply system is turned on to provide water-based additives to the processing station for surface thinning treatment of the cut sheet to be processed. When the thinning thickness of the cut sheet to be processed is not less than the set target value and the abrasive layer of the composite polishing pad is completely removed, the first liquid supply system is turned off and the second liquid supply system is turned on to provide polishing liquid to the processing station for surface polishing treatment of the cut sheet to be processed.

[0021] Optionally, in the above surface processing method, during the surface processing of the cutting disc, the thinning thickness of the cutting disc is detected in real time, including: Based on a non-contact laser interferometry method, multiple monitoring points are uniformly selected on the surface of the cut sheet to be processed for thickness measurement.

[0022] Optionally, the above surface processing method further includes: during the surface thinning process, when the thickness deviation of a local area of ​​the cut disc to be processed exceeds a set threshold, adjusting the grinding pressure and / or grinding speed of the local area to reduce the thickness deviation.

[0023] Optionally, in the above surface processing method, the target value is set to 25μm~100μm.

[0024] Optionally, in the above surface processing method, the processing time for surface polishing is 1h to 4h.

[0025] By employing the above technical solution, the surface processing equipment and method for the cutting disc provided in this application, based on independently controllable first and second liquid supply systems, allows the surface processing equipment to alternately activate the first and second liquid supply systems according to the required thinning thickness of the cutting disc. This enables the same processing station within the same surface processing equipment to sequentially perform surface thinning and surface polishing processes on the cutting disc. Specifically, the surface thinning process can quickly remove the larger surface thickness of the cutting disc, thereby removing surface saw marks and damage, reducing surface roughness, and improving the surface profile, achieving rough grinding and rough polishing of the cutting disc surface. The surface polishing process can reduce surface roughness and eliminate scratches, further improving surface smoothness, achieving fine polishing of the cutting disc surface to meet the requirements of subsequent device fabrication. This application allows for one-step grinding and polishing of the surface of the cutting disc to be processed at the same processing station on the same processing equipment, saving the multiple transfer and cleaning steps required between different processes in conventional solutions. Therefore, the technical solution of this application simplifies the process flow for surface processing of the cutting disc to be processed, shortens the processing cycle, reduces process and equipment costs, and can also improve the surface quality and thickness uniformity of the cutting disc to be processed. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0028] Figure 1 This is a schematic diagram of the structure of a surface processing device for a cutting disc provided in an embodiment of this application; Figure 2 for Figure 1 The diagram shows the structure of the composite polishing pad in the surface processing equipment shown. Figure 3 for Figure 2 A schematic diagram of the composite polishing pad when the abrasive layer is completely removed; Figure 4 A top view of a polishing pad substrate provided in an embodiment of this application; Figure 5 A top view of a composite polishing pad provided in an embodiment of this application; Figure 6 This is a schematic flowchart of a method for processing the surface of a cutting disc, provided in an embodiment of this application.

[0029] The annotations in the attached figures are explained as follows: 100 Machine body; 101 Processing station; 102 Composite polishing pad; 103 Polishing pad base; 104 Abrasive layer; 1041 Agglomerated diamond micro powder; 1042 Alumina particles; 105 First liquid supply system; 106 Second liquid supply system; 107 Water-based additive; 108 Polishing fluid; 109 Circulation pump; 110 Stirring rod; 111 Liquid tank; 112 Upper polishing disc; 113 Lower polishing disc; 114 Thickness detection device; 115 Adhesive backing; 116 First grid groove; 117 Ventilation hole; 118 Second grid groove. Detailed Implementation

[0030] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0031] As described in the background section, when performing surface processing on the cutting disc, the existing technology requires separate processing equipment and processes for rough grinding, fine grinding, rough polishing, and fine polishing of the cutting disc, which results in many problems such as low processing efficiency, high cost, cross-contamination between processes, and cumulative errors.

[0032] To address the aforementioned problems, embodiments of this application provide a surface processing apparatus for a cutting disc, comprising: The main body of the machine tool has a processing station for holding the cutting disc to be processed; A composite polishing pad is arranged opposite to the processing station. The composite polishing pad includes a polishing pad base and an abrasive layer disposed on one side surface of the polishing pad base. The first liquid supply system is used to supply water-based additives to the processing station; The second liquid supply system is used to supply polishing liquid to the processing station; The controller, after the processing equipment is started, controls the operating status of the first and second liquid supply systems based on the thinning thickness of the cutting disc to be processed. When the thinning thickness is less than a set target value, the controller shuts off the second liquid supply system and opens the first liquid supply system to provide water-based additives to the processing station for surface thinning treatment of the cutting disc. When the thinning thickness is not less than the set target value and the abrasive layer of the composite polishing pad is completely removed, the controller shuts off the first liquid supply system and opens the second liquid supply system to provide polishing fluid to the processing station for surface polishing treatment of the cutting disc. The thinning thickness is the cumulative thickness removed from the cutting disc.

[0033] As described above, the surface processing equipment for the cutting disc provided in this application embodiment is equipped with a first liquid supply system and a second liquid supply system that can be independently controlled. This allows the surface processing equipment to alternately activate the first and second liquid supply systems according to the required thinning thickness of the cutting disc, enabling sequential surface thinning and polishing treatments at the same processing station within the same surface processing equipment. Specifically, the surface thinning treatment can quickly remove a large surface thickness from the cutting disc, thereby removing surface scratches and damage, reducing surface roughness, and improving the surface profile, achieving rough grinding and rough polishing of the cutting disc surface. The surface polishing treatment can reduce surface roughness and eliminate scratches, further improving surface smoothness, achieving fine polishing of the cutting disc surface to meet the requirements of subsequent device fabrication.

[0034] As can be seen, compared with the conventional solution that requires separate processing equipment and processing steps for rough grinding, fine grinding, rough polishing and fine polishing, the technical solution of this application can integrate the thinning treatment and polishing treatment into the same processing station of the same equipment. The seamless connection between surface thinning treatment and surface polishing treatment is achieved through the intelligent switching of the liquid supply system. The surface of the cutting disc to be processed can be ground and polished in one step through the same processing station of the same processing equipment, saving the multiple transfer and cleaning steps between different processes required in the conventional solution. Therefore, the technical solution of this application simplifies the process flow of surface processing of the cutting disc to be processed, shortens the processing cycle, reduces process cost and equipment cost, and can also improve the surface quality and thickness uniformity of the cutting disc to be processed.

[0035] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments described in this application are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The terminology used in the embodiments of this application is only used to explain the specific embodiments of this application and is not intended to limit this application.

[0036] refer to Figures 1-3 , Figure 1 This is a schematic diagram of the structure of a surface processing device for a cutting disc provided in an embodiment of this application. Figure 2 for Figure 1 The schematic diagram shown is of the structure of the composite polishing pad 102 in the surface processing equipment. Figure 3 for Figure 2 The schematic diagram shown illustrates the structure of the composite polishing pad 102 when the abrasive layer 104 is completely removed. The surface processing equipment includes: The machine body 100 has a processing station 101 for carrying the cutting disc to be processed; Figures 1-3 The cutting disc to be processed is not shown in the image. A composite polishing pad 102 is disposed opposite to the processing station 101. The composite polishing pad 102 includes a polishing pad base 103 and an abrasive layer 104 disposed on one side surface of the polishing pad base 103. The first liquid supply system 105 is used to supply water-based additives 107 to the processing station; The second liquid supply system 106 is used to supply polishing liquid 108 to the processing station; The controller is used to control the working state of the first liquid supply system 105 and the second liquid supply system 106 based on the thinning thickness of the cutting disc to be processed after the processing equipment is started. When the thinning thickness is less than the set target value, the controller controls the second liquid supply system 106 to be turned off and the controller controls the first liquid supply system 105 to be turned on, so as to provide water-based additive 107 to the processing station 101 for surface thinning treatment of the cutting disc to be processed. When the thinning thickness is not less than the set target value and the abrasive layer 104 of the composite polishing pad 102 is completely removed, the controller controls the first liquid supply system 105 to be turned off and the controller controls the second liquid supply system 106 to be turned on, so as to provide polishing liquid 108 to the processing station 101 for surface polishing treatment of the cutting disc to be processed.

[0037] like Figure 1As shown, both the first liquid supply system 105 and the second liquid supply system 106 include a liquid tank 111. The liquid tank 111 contains a stirring rod 110 for stirring the processing liquid within the tank. The liquid tank 111 in the first liquid supply system 105 is used to store water-based additives 107. The liquid tank 111 in the second liquid supply system 106 is used to store polishing liquid 108. Each of the two liquid tanks 111 is connected to a circulation pump 109 via a liquid supply pipeline. The controller can control the operation of the circulation pumps 109 in each liquid supply system to control the opening or closing of the liquid supply system.

[0038] The target value mentioned above can be set based on factors such as the initial thickness of the cutting disc to be processed, the target finished product thickness, and the depth of the damaged layer on the surface of the cutting disc. Optionally, the target value can be set to 25μm~100μm. The target value can be selected within this range according to actual processing requirements.

[0039] Alternatively, the controller can be implemented using conventional control hardware in the field, such as a programmable logic controller (PLC), an industrial computer, or an embedded control motherboard.

[0040] During the surface thinning process, the water-based additive 107 provided by the first liquid supply system 105 mainly plays the role of cooling and chip removal. It can remove the heat generated during the processing in time, avoid thermal damage to the cutting disc due to local overheating, and at the same time, wash away the chips and abrasive particles generated during processing from the processing interface to prevent them from scratching the surface of the cutting disc or causing agglomeration. It can also adjust the pH value of the processing surface to ensure the stability of the pH value during the surface thinning process and ensure the stability of the chemical reaction.

[0041] During the surface polishing process, the polishing fluid 108 provided by the second fluid supply system 106 is used to flatten the surface of the cut disc to be processed and reduce the surface roughness during the finishing stage.

[0042] like Figure 2 and Figure 3 As shown, the two figures are side views of the composite polishing pad 102. The composite polishing pad 102 also includes an adhesive backing 115, located on the side of the polishing pad base 103 opposite to the abrasive layer 104. The machine body 100 includes a polishing disc, and the adhesive backing 115 is used to bond and fix the composite polishing pad 102 and the polishing disc in the machine body 100. The polishing pad base 103 supports the abrasive layer 104 and provides a certain elastic support to ensure uniform contact pressure between the abrasive layer 104 and the surface of the cutting disc to be processed. The abrasive layer 104 contains abrasive grains for material removal from the surface of the cutting disc during processing.

[0043] In the surface processing equipment for cutting discs provided in this application embodiment, when the thinning thickness of the cutting disc to be processed is less than a set target value, the second liquid supply system 106 is turned off and the first liquid supply system 105 is turned on to provide water-based additive 107 to the processing station 101. The composite polishing pad 102 can perform thinning treatment on the surface of the cutting disc to be processed based on the water-based additive 107 to quickly thin the surface of the cutting disc to be processed. When the thinning thickness is not less than the set target value and the abrasive layer 104 on the surface of the composite polishing pad 102 is completely removed, the first liquid supply system 105 is turned off and the second liquid supply system 106 is turned on to provide polishing liquid 108 to the processing station 101. The composite polishing pad 102 can perform polishing treatment on the surface of the cutting disc to be processed based on the polishing liquid 108.

[0044] As can be seen, the technical solution of this application can adapt the liquid supply status of the two liquid supply systems to the thinning thickness of the cutting disc during the surface treatment process. The cutting disc is first subjected to surface thinning treatment at the same processing station 101 of the same surface processing equipment, and then surface polishing treatment is performed. This technical solution can achieve seamless connection between surface thinning and surface polishing treatments through intelligent switching of the liquid supply systems. The surface of the cutting disc can be ground and polished in one step at the same processing station 101 of the same processing equipment, saving the multiple transfer and cleaning steps required between different processes in conventional solutions.

[0045] The main body 100 serves as the load-bearing foundation for the entire equipment, providing installation support for all components and ensuring the relative positional accuracy between the parts during processing. The main body 100 can adopt a conventional grinding and polishing equipment frame structure, and its specific materials and shape can be selected according to the actual equipment scale.

[0046] The main body 100 of the machine includes a polishing disc, and a composite polishing pad 102 is fixed on the side of the polishing disc opposite to the processing station 101 for surface processing of the cutting disc to be processed.

[0047] In one implementation, such as Figure 1 As shown, the machine body 100 includes an upper polishing disc 112 and a lower polishing disc 113 arranged opposite to each other; each of the upper polishing disc 112 and the lower polishing disc 113 is fixed with a composite polishing pad 102, the abrasive layers 104 of the two composite polishing pads 102 are arranged opposite to each other, and the processing station is located between the two composite polishing pads 102; wherein, the machine body 100 also includes a lifting drive mechanism ( Figure 1(A lifting drive mechanism is not shown in the diagram). The lifting drive mechanism is connected to at least one of the upper polishing disk 112 and the lower polishing disk 113, and is used to control the vertical height position of at least one of the upper polishing disk 112 and the lower polishing disk 113. Optionally, the lifting mechanism can be connected to the upper polishing disk 112 to drive the upper polishing disk 112 to move up and down in the vertical direction, thereby adjusting the distance between the upper polishing disk 112 and the lower polishing disk 113 to meet the processing requirements of cutting discs of different thicknesses.

[0048] The lifting mechanism can also adjust the pressure on the surface of the cutting disc during processing. The lifting mechanism can be implemented using a hydraulic cylinder, a servo motor with a lead screw and nut mechanism, or other linear drive devices.

[0049] exist Figure 1 In the illustrated configuration, the machine body 100 includes two polishing discs, located on the upper and lower sides of the processing station 101, respectively. The polishing disc located on the upper side of the processing station 101 is the upper polishing disc 112, and the polishing disc located on the lower side of the processing station 101 is the lower polishing disc 113. The abrasive layers 104 of the composite polishing pads 102 fixed on the two polishing discs are arranged opposite each other. When the cutting disc to be processed is surface-processed, the cutting disc to be processed is located between the two composite polishing pads 102, and the abrasive layers 104 of the two composite polishing pads 102 are in contact with the upper and lower surfaces of the cutting disc to be processed, respectively, thereby achieving simultaneous double-sided polishing of the cutting disc to be processed.

[0050] In the double-sided processing method, the upper and lower surfaces of the cutting disc to be processed are polished at the same time. This not only improves the processing speed, but also makes the stress distribution on the upper and lower surfaces of the cutting disc symmetrical. This can effectively suppress the warping problem of the cutting disc caused by uneven stress due to single-sided processing, and is conducive to obtaining better surface accuracy.

[0051] In other methods, the surface processing equipment can also be a single-sided processing equipment. In this case, the main body 100 of the machine has a platform, and the platform has a processing station 101 for placing the cutting disc to be processed. A polishing disc is provided above the platform, and a composite polishing pad 102 is fixed below the polishing disc.

[0052] like Figure 1 As shown, the surface processing equipment also includes a thickness detection device 114, used to detect the thinning thickness of the cutting disc to be processed. The thickness detection device 114 is used to detect the thinning thickness of the cutting disc to be processed. During processing, the thickness detection device 114 can acquire the thickness data of the cutting disc in real time and transmit the data to the controller, which serves as the basis for the controller to determine whether the thinning thickness has reached the set target value.

[0053] Optionally, the thickness detection device 114 can employ a contact thickness gauge or a non-contact thickness gauge. A contact thickness gauge calculates the thickness by measuring the change in the contact position between the probe and the surface of the cutting disc; however, its measurement accuracy is significantly affected by the contact force and may scratch the surface of the cutting disc. Therefore, the thickness detection device 114 preferably employs a non-contact thickness gauge to avoid mechanical contact and potential damage to the surface of the cutting disc, while achieving higher measurement accuracy and faster response speed.

[0054] In one embodiment, the thickness detection device 114 is based on a non-contact laser interferometry method, uniformly selecting multiple monitoring points on the surface of the cut sheet to be processed for thickness measurement. Laser interferometry is a high-precision measurement method that utilizes the interference phenomenon generated by the reflection of a laser beam on the upper and lower surfaces of the cut sheet to measure thickness. Its basic principle is as follows: a laser beam is projected onto the surface of the cut sheet, and the laser beam is reflected from both the upper and lower surfaces of the cut sheet. The two reflected beams are superimposed to form interference fringes. By analyzing the intensity changes or phase differences of the interference fringes, combined with the known refractive index of the cut sheet material, the thickness value at the measurement point can be calculated. The accuracy of this measurement method can reach ±0.1 μm, allowing for accurate real-time detection of the thinning thickness during the processing of the cut sheet.

[0055] In this embodiment, to ensure comprehensive coverage of the entire processing area by the thickness detection area, multiple monitoring points are uniformly selected on the surface of the wafer to be processed for measurement. The spacing between adjacent monitoring points is set to 20 mm. Taking a 6-inch (approximately 150 mm) silicon carbide wafer as an example, approximately 30-50 monitoring points can be uniformly selected on the same surface of the silicon carbide wafer, covering the central and edge areas of the surface, to ensure comprehensive monitoring of the thickness distribution of the entire processing area. Preferably, the monitoring points can be arranged in a concentric circle equidistant distribution or a grid dot matrix distribution.

[0056] When detecting the thinning thickness of the cutting disc to be processed, the monitoring frequency is set to collect data once every 10 seconds. The collected data is uploaded to the processor for analysis and processing via a high-speed data transmission module. When the monitoring data shows that the thickness deviation in a local area exceeds the set threshold, the surface processing equipment can automatically adjust the grinding pressure and / or grinding speed of that local area to compensate for the uneven thickness and reduce the thickness deviation in different areas. For example, when the thickness value of the edge area of ​​the cutting disc is detected to be greater than that of the center area, the surface processing equipment can appropriately increase the grinding pressure and / or increase the grinding speed of the edge area to increase the material removal rate of the edge area, thereby making the thickness distribution on the entire surface more uniform.

[0057] The abrasive layer 104 includes a matrix material and abrasive uniformly mixed in the matrix material. The abrasive includes granular abrasive grains with a set particle size.

[0058] like Figure 2 As shown, the abrasive in the abrasive layer 104 includes at least two different types of abrasive grains with different particle sizes. Using a mixture of two or more different materials and particle sizes as the abrasive in the abrasive layer 104 allows for the synergistic removal of defects of different scales on the surface of the cutting disc to be processed. Larger-sized hard abrasive grains (such as agglomerated diamond micropowder 1041) can be used to quickly remove saw marks and deeper damage layers introduced by wire cutting, achieving high-efficiency material thinning; smaller-sized soft abrasive grains (such as alumina particles 1042) can be used to repair surface micro-scratches remaining after processing with larger abrasive grains, improving surface smoothness. The different particle sizes of the abrasive grains can create a gradation effect during processing, which is beneficial for obtaining better surface quality.

[0059] The dispersion of abrasive particles in the substrate material within the abrasive layer 104 can be achieved using an ultrasonic-assisted mixing process. After mixing the abrasive particles and substrate material in a predetermined ratio, the mixture is placed in an ultrasonic dispersion device for ultrasonic treatment. Utilizing the cavitation effect generated by ultrasound in a liquid, the agglomerated abrasive particles are effectively broken up and uniformly dispersed within the substrate material, forming a uniformly mixed abrasive slurry. This abrasive slurry is then evenly coated onto one side of the polishing pad substrate 103, and after curing, forms the abrasive layer 104. Compared to traditional mechanical stirring and dispersion methods, the ultrasonic-assisted mixing process achieves better dispersion results and avoids excessive localized wear or scratches caused by abrasive agglomeration.

[0060] Optionally, the matrix material used for the abrasive layer 104 is the same as that used for the polishing pad substrate 103, in order to improve the adhesion stability and reliability of the abrasive layer 104 on the polishing pad substrate 103. For example, both the matrix material and the polishing pad substrate 103 can be polyurethane, and the polishing pad substrate 103 can be a polyurethane substrate, which is a thermoplastic polyurethane elastomer with high strength, high wear resistance and good flexibility.

[0061] In this embodiment, the polishing slurry 108 includes silica gel abrasive particles, the particle size of which is smaller than the particle size of at least one abrasive particle in the abrasive layer 104. Optionally, the polishing slurry 108 is a Si sol-gel abrasive polishing slurry 108, which uses silica gel abrasive particles as the main abrasive component, combined with appropriate dispersants and pH adjusters to form a stable and dispersed colloidal system.

[0062] During the surface thinning process, a water-based additive 107 is supplied to the processing surface through the first liquid supply system 105. In this process, the abrasive grains in the abrasive layer 104 mainly rely on mechanical removal of the surface of the cutting disc to be processed. The removal efficiency is high, but the surface roughness is relatively large. During the surface polishing process, a polishing liquid 108 is supplied to the processing surface through the second liquid supply system 106. In this process, the fine abrasive grains in the polishing liquid 108 mainly rely on fine removal of the cutting disc surface. The removal efficiency is lower, but an extremely low surface roughness can be obtained.

[0063] like Figure 2 As shown, for the composite polishing pad 102, the abrasive particles in the abrasive layer 104 include agglomerated diamond micro powder 1041 and alumina particles 1042; wherein, the mass proportion of agglomerated diamond micro powder 1041 is greater than the mass proportion of alumina particles 1042, and the particle size of agglomerated diamond micro powder 1041 is greater than the particle size of alumina particles 1042.

[0064] Diamond is the hardest known material in nature, possessing extremely high hardness and wear resistance, making it an ideal abrasive for machining hard and brittle materials such as silicon carbide. Agglomerated diamond micropowder 1041 is a secondary particle formed from multiple micron- or submicron-sized primary diamond particles through an agglomeration process. Its size can be controlled by agglomeration process parameters. Compared to single-crystal diamond micropowder, agglomerated diamond micropowder 1041 exhibits better self-sharpening properties during processing. After the abrasive particles become passivated, the agglomerated particles gradually disintegrate, exposing new sharp cutting edges, thus maintaining continuous material removal capability.

[0065] Alumina (Al2O3) has a hardness lower than diamond but higher than most processed materials, exhibiting good chemical and thermal stability. An abrasive layer 104 is prepared by mixing alumina particles 1042 with agglomerated diamond powder 1041. This serves two purposes: firstly, the grinding action of the alumina particles 1042 assists the agglomerated diamond powder 1041 in material removal; secondly, the alumina particles 1042 can somewhat repair the micro-scratches generated after processing the agglomerated diamond powder 1041, reducing surface roughness.

[0066] The agglomerated diamond micropowder 1041 has a higher mass proportion than the alumina particles 1042, ensuring that the abrasive layer 104 has sufficiently high-hardness abrasive to guarantee material removal efficiency. Simultaneously, the particle size of the agglomerated diamond micropowder 1041 is larger than that of the alumina particles 1042, allowing the two different abrasive materials to form a coarse-to-fine abrasive grain gradation structure. During processing, the larger-sized agglomerated diamond micropowder 1041 primarily performs the material removal function, while the smaller-sized alumina particles 1042 partially repair the micro-scratches remaining after processing with the agglomerated diamond micropowder 1041, while simultaneously protecting the polishing pad substrate 103 from excessive wear.

[0067] In this embodiment, the mass ratio of agglomerated diamond micropowder 1041 to alumina particles 1042 is 3:2. If the proportion of agglomerated diamond micropowder 1041 is too high, although the material removal rate increases, the scratch depth and density on the surface of the cut disc after processing increase significantly, increasing the burden on subsequent polishing processes. If the proportion of alumina particles 1042 is too high, the overall hardness of the abrasive layer 104 is insufficient, the material removal rate decreases, and the processing efficiency is reduced. Therefore, when the mass ratio of agglomerated diamond micropowder 1041 to alumina particles 1042 is 3:2, sufficient material removal efficiency is ensured while reasonable surface quality is obtained, representing the optimal balance between processing efficiency and processing quality.

[0068] The particle size of agglomerated diamond micropowder 1041 is 5μm to 10μm. If the particle size of agglomerated diamond micropowder 1041 is less than 5μm, the single cutting depth of the abrasive is too small, the material removal rate is too low, and the processing efficiency decreases. If the particle size of agglomerated diamond micropowder 1041 is greater than 10μm, the single cutting depth is too large, which easily produces deep scratches and subsurface damage on the surface of the cutting disc, increasing the difficulty of subsequent polishing or even making complete removal impossible. Therefore, when the particle size of agglomerated diamond micropowder 1041 is 5μm to 10μm, both processing efficiency and processing quality can be balanced.

[0069] The alumina particles 1042 have a particle size of 0.1 μm to 1 μm. Alumina particles 1042 in this size range are smaller than the agglomerated diamond micropowder 1041, and are used to fill the gaps between the agglomerated diamond micropowder 1041 particles and to repair micro-scratches generated after processing the agglomerated diamond micropowder 1041. If the particle size of the alumina particles 1042 is greater than 1 μm, the repairing effect of the abrasive particles will be insufficient, and the surface roughness cannot be effectively reduced; if the particle size of the alumina particles 1042 is less than 0.1 μm, the grinding effect is too weak, and the repairing effect is not obvious.

[0070] In this embodiment, the particle size of the silica abrasive particles is 80nm~120nm. The particle size of the silica abrasive particles is much smaller than the particle size (5μm~10μm) of the agglomerated diamond micropowder 1041 in the abrasive layer 104, and also smaller than most particles in the alumina particles 1042 (0.1μm~1μm). This particle size relationship ensures that after switching from surface thinning treatment to surface polishing treatment, the abrasive size at the processing interface decreases stepwise, thereby achieving a natural transition from roughing to finishing and avoiding unstable surface quality caused by abrupt changes in abrasive size.

[0071] refer to Figure 4 , Figure 4This is a top view of a polishing pad substrate 103 provided in an embodiment of this application. At this point, the polishing pad substrate 103 is used to polish one side of the surface of the cut disc to be processed, before the abrasive layer 104 is prepared. The polishing pad substrate 103 has a first mesh groove 116 on the side facing the abrasive layer 104. During the surface processing of the cut disc, after the abrasive layer 104 is completely removed, the first mesh groove 116 can be used to guide the processing liquid (water-based additive 107 and polishing liquid 108), allowing the processing liquid to be evenly distributed across the entire surface of the cut disc, improving the uniformity of the surface processing; it can also increase the contact area between the composite polishing pad 102 and the processing liquid, improving the heat exchange efficiency of the processing interface between the composite polishing pad 102 and the cut disc; and it can also remove the waste generated during polishing.

[0072] Optionally, in the first grid trench 116, the width of the trench can be 20μm, the depth can be 20μm, and the spacing can be 80μm.

[0073] like Figure 4 As shown, the composite polishing pad 102 also includes multiple ventilation holes 117 penetrating the polishing pad substrate. The composite polishing pad 102 can be provided with multiple honeycomb-shaped ventilation holes 117. During processing, the ventilation holes 117 can increase the gas flow rate to quickly remove the heat generated during processing, reducing the temperature of the processing interface between the composite polishing pad 102 and the cutting disc to be processed; they can also provide a certain deformation space when the polishing pad substrate 103 is compressed, increasing the elasticity of the composite polishing pad 102 and its adaptability to the surface contour of the cutting disc to be processed; and they can also reduce the overall weight of the composite polishing pad 102, facilitating installation and replacement.

[0074] In this embodiment, the core support structure (polishing pad substrate 103) of the composite polishing pad 102 is made of thermoplastic polyurethane elastomer (TPU), which has high strength, high wear resistance, and good flexibility. TPU material has excellent comprehensive mechanical properties, capable of withstanding the pressure during processing without plastic deformation, and also possessing a certain degree of elasticity to adapt to the minute undulations on the cutting surface, ensuring uniform distribution of processing pressure. The thickness of the uppermost composite abrasive layer 104 is 5μm to 50μm. Depending on the set removal amount, composite polishing pads 102 with abrasive layers 104 of different thicknesses can be selected. Preferably, the thickness of the abrasive layer 104 is 10μm.

[0075] refer to Figure 5 , Figure 5 This is a top view of a composite polishing pad 102 provided in an embodiment of this application. Figure 5A top view of one side surface of the composite polishing pad 102 where the abrasive layer 104 is provided. The surface of the abrasive layer 104 has a second grid groove 118. During the surface processing of the cutting disc to be processed, when the abrasive layer 104 is not completely removed, the second grid groove 118 on the surface of the abrasive layer 104 can be used to guide the processing liquid (water-based additive 107 and polishing liquid 108), so that the processing liquid can be evenly distributed on the entire surface of the cutting disc to be processed, improving the uniformity of surface processing; it can also increase the contact area between the composite polishing pad 102 and the processing liquid, improving the heat exchange efficiency of the processing interface between the composite polishing pad 102 and the cutting disc to be processed; and it can also remove the waste chips generated by polishing.

[0076] To facilitate the fabrication of the composite polishing pad 102, the first grid groove 116 and the second grid groove 118 can have the same graphic structure and be positioned opposite each other. This allows the first grid groove 116 and the second grid groove 118 to be fabricated using the same grid groove design parameters.

[0077] In one approach, such as Figure 5 As shown, the ventilation hole 117, which penetrates the polishing pad substrate 103, also penetrates the abrasive layer 104. In other embodiments, the ventilation hole 117 may not penetrate the abrasive layer 104.

[0078] Based on the surface processing equipment provided in the above embodiments, this application also provides a surface processing method for a cutting disc, the surface processing method being as follows: Figure 6 As shown.

[0079] refer to Figure 6 , Figure 6 This is a schematic flowchart illustrating a surface processing method for a cutting disc provided in an embodiment of this application. The surface processing method for the cutting disc includes: Step S11: Place the cutting disc to be processed on the processing station 101 in the surface processing equipment and perform surface processing on the cutting disc.

[0080] Before step S11, it is necessary to prepare the wafers to be processed. The preparation process for the wafers to be processed includes: obtaining multiple wafers that require surface processing from a semiconductor crystal (such as a silicon carbide crystal) through multi-wire cutting. The thickness of the wafers to be processed can be determined according to the crystal type and cutting process. Taking silicon carbide wafers as an example, the thickness of the wafers to be processed is usually 375μm~450μm.

[0081] Before formally processing the cut disc using surface finishing equipment, the initial thickness of the disc can be tested to set a reasonable target removal amount. Before starting the surface finishing equipment, the machine needs to be cleaned and the composite polishing pad 102 needs to be adjusted. 10L~50L of water-based additive 107 is added to the liquid tank 111 of the first liquid supply system 105, and 10L~50L of polishing liquid 108 is added to the liquid in the second liquid supply system 106. Machine cleaning removes any impurities and contaminants that may be present inside the equipment, preventing interference with the processing. Adjusting the composite polishing pad 102 involves running it in before formal processing to stabilize its surface and achieve good flatness, thereby ensuring uniform pressure distribution during processing.

[0082] During subsequent surface processing, when the liquid supply system is turned on to supply the processing liquid, the processing liquid in the liquid tank 111 is simultaneously stirred by the stirring rod 110.

[0083] Step S12: During the surface processing of the cutting disc, the thinning thickness of the cutting disc is detected in real time.

[0084] In the surface processing method provided in this application embodiment, real-time detection of the thinning thickness is used to monitor the processing progress, determine whether the set target removal amount has been reached, and promptly detect abnormalities in the processing process, such as uneven local removal or sudden changes in processing rate.

[0085] Step S13: Based on the thinning thickness, control the working state of the first liquid supply system 105 and the second liquid supply system 106; wherein, when the thinning thickness of the cut sheet to be processed is less than the set target value, the second liquid supply system 106 is turned off and the first liquid supply system 105 is turned on to provide water-based additive 107 to the processing station 101 for surface thinning treatment of the cut sheet to be processed; when the thinning thickness of the cut sheet to be processed is not less than the set target value and the abrasive layer 104 of the composite polishing pad 102 is completely removed, the first liquid supply system 105 is turned off and the second liquid supply system 106 is turned on to provide polishing liquid 108 to the processing station 101 for surface polishing treatment of the cut sheet to be processed.

[0086] During the surface thinning process, the agglomerated diamond micropowder 1041 and alumina particles 1042 in the abrasive layer 104 of the composite polishing pad 102, with the cooling and chip removal assistance of the water-based additive 107, perform rough grinding and rough polishing on the surface of the cutting disc, removing saw marks and surface damage layers introduced by wire cutting, improving surface smoothness, and eliminating deep scratches. The surface thinning process is actually a superposition of rough grinding and rough polishing. When the abrasive layer 104 is relatively thick, the cutting action of the hard abrasive grains is strong, mainly for material removal; as the abrasive layer 104 gradually wears down, the cutting depth of the abrasive grains decreases, gradually transitioning to mainly surface smoothing. Therefore, the water-based additive 107 in the liquid tank 111 of the first liquid supply system 105 simultaneously plays the role of rough grinding and rough polishing.

[0087] During the surface polishing process, the abrasive layer 104 of the composite polishing pad 102 is completely removed, leaving only the polishing pad base 103. At this point, since the abrasive layer 104 is completely consumed, the hard coarse abrasive grains in the abrasive layer 104 no longer participate in the processing. The silica gel abrasive grains in the polishing slurry 108 perform fine material removal on the surface of the cutting disc using a chemical mechanical polishing (CMP) mechanism, mainly removing micro-scratches remaining from the surface thinning process and reducing the surface roughness to atomic-level flatness. The preferred processing time for the surface polishing process is 1 hour to 4 hours.

[0088] After surface polishing, the finished wafer is obtained, which can be further cleaned and inspected. After cleaning, the wafer can be tested for flatness using an FM200 flatness testing device (test parameters include total thickness change and warp), surface scratches using a CS8520 surface quality inspection device, and surface roughness (Ra) using an AFM atomic force microscope.

[0089] During the surface processing of the cutting disc, the thinning thickness of the disc is monitored in real time. This includes using a non-contact laser interferometry method to uniformly select multiple monitoring points on the surface of the disc for thickness measurement. Before the equipment starts, the thickness detection device 114 first measures the initial thickness of the disc to obtain the initial thickness value at each monitoring point. During processing, the thickness detection device 114 continuously measures the thickness at each monitoring point in real time. The difference between the current thickness value and the initial thickness value at each monitoring point is the thinning thickness at that monitoring point. The average thinning thickness at each monitoring point is used as the overall thinning thickness of the disc at the current moment, which is used by the controller to determine whether the set target value has been reached.

[0090] Optionally, multiple monitoring points are evenly arranged on the surface of the cut sheet to be processed, with a spacing of 20 mm between adjacent monitoring points. Preferably, the monitoring frequency is once every 10 seconds. In this application, the measurement accuracy of the thinning thickness reaches ±0.1 μm.

[0091] The surface processing method provided in this application embodiment further includes: during the surface thinning process, when the thickness deviation of a local area of ​​the cut sheet to be processed is greater than a set threshold, adjusting the grinding pressure and / or grinding speed of the local area to reduce the thickness deviation.

[0092] During the surface thinning process, the removal rate may vary in different areas of the cutting disc due to the increased temperature at the processing interface and the uneven distribution of abrasive particles. To further improve thickness uniformity, when real-time thickness detection detects that the thickness deviation in a local area of ​​the cutting disc exceeds a set threshold, the system automatically adjusts the grinding pressure and / or grinding speed in that local area to compensate for the thickness deviation and make the thickness of each area of ​​the cutting disc more consistent.

[0093] Specifically, the thickness detection device 114 transmits the thickness data of each monitoring point to the controller in real time. The controller performs statistical analysis on the thickness data of each monitoring point, calculating the current thickness and the thinning thickness at each monitoring point. When the absolute value of the deviation between the thinning thickness at a certain monitoring point and the average thinning thickness of all monitoring points exceeds a set threshold (such as ±0.5μm or other calibrated reference value), the controller determines that there is a thickness deviation in the area where the monitoring point is located. For areas where the thinning thickness is less than the average value (i.e., the area is under-removed), the controller increases the local processing pressure or increases the local rotation speed in that area through the lifting drive mechanism to increase the material removal rate in that area, so that the thinning thickness in that area gradually approaches the average value. For areas where the thinning thickness is greater than the average value (i.e., the area is over-removed), the controller decreases the local processing pressure or decreases the local rotation speed in that area through the lifting drive mechanism to reduce the material removal rate in that area and prevent further over-removal in that area. Through the above adaptive compensation mechanism, the thickness distribution of the cutting disc on the entire surface tends to be uniform.

[0094] Optionally, the target value is set to 25μm~100μm. This target value refers to the cumulative amount of material removed by the cutting disc when switching from the surface thinning stage to the surface polishing stage.

[0095] For silicon carbide dicing wafers, the depth of the damage layer introduced by multi-wire cutting is typically approximately 20 μm to 100 μm. The target value should be set at least greater than the damage layer depth to ensure complete removal of the damage layer during the surface thinning stage. However, the target value should not be set too high, otherwise the surface thinning stage will be too time-consuming, and excessive mechanical removal will create a deeper subsurface damage layer, increasing the burden on subsequent surface polishing. Preferably, the target value is set to 58 μm, which ensures complete removal of the saw marks and damage layer on the wafer surface without creating new damage due to over-removal.

[0096] The specific value of the target value can be determined comprehensively based on the following factors: the material type and hardness of the cutting disc to be processed; the initial damage layer depth on the surface of the cutting disc after wire cutting; the target finished thickness and initial thickness of the cutting disc to be processed; and the thickness of the abrasive layer 104 of the composite polishing pad 102. Optionally, the target value can also be designed to match the thickness of the abrasive layer 104. For example, when the thickness of the abrasive layer 104 is determined, the target value can be set as a positive multiple of the thickness of the abrasive layer 104, and the specific multiple depends on the ratio of the material removal rate of the abrasive particles in the abrasive layer 104 to the wear rate of the abrasive layer 104 itself.

[0097] As described above, the processing time for surface polishing is 1 to 4 hours. The time required for surface polishing depends on the following factors: the initial roughness of the surface of the cutting disc after surface thinning; the required surface roughness; the concentration and particle size of the silica abrasive particles in the polishing slurry 108; and process parameters such as processing pressure and rotation speed.

[0098] If the processing time is less than 1 hour, the silica gel abrasive particles will not have enough time to act on the surface of the cutting disc, making it difficult to completely remove the micro-scratches remaining after surface thinning treatment, and the surface roughness will not meet the requirements. If the processing time is greater than 4 hours, the amount of material removed from the cutting disc may exceed expectations, and excessive polishing will cause surface corrosion or selective corrosion, which is detrimental to improving surface quality. Preferably, the surface polishing treatment takes 3 hours.

[0099] During the surface polishing stage, the silica abrasive particles in the polishing slurry 108 remove material from the surface of the cutting disc through a combination of chemical and mechanical action. Taking a silicon carbide cutting disc as an example, the pH value of the polishing slurry 108 is typically adjusted to an alkaline range (e.g., pH 9-11). Under these conditions, the silicon carbide surface is oxidized to form a relatively soft oxide layer. The silica abrasive particles remove this oxide layer through mechanical friction, exposing a fresh silicon carbide surface, which is then further oxidized, forming a dynamic cycle of oxidation-removal-re-oxidation. This chemical-mechanical polishing mechanism allows the surface polishing process to achieve extremely low surface roughness while avoiding subsurface damage caused by pure mechanical polishing.

[0100] As can be seen from the above description, the technical solution of this application embodiment can improve the surface processing efficiency of the cutting disc to be processed. The cutting disc to be processed can be ground and polished in one step at the same processing station 101 of the same surface processing equipment, and the cutting disc to be processed can be subjected to surface thinning treatment and surface polishing treatment in sequence. This significantly simplifies the surface processing process of cutting discs made of materials such as silicon carbide and effectively reduces the number of processing steps.

[0101] The surface processing method provided in this application is a one-step grinding and polishing process, which can reduce processing costs when processing the cutting disc. Compared with conventional techniques, the technical solution of this application can effectively control costs in multiple ways by reducing processing steps. First, the processes in traditional cutting disc surface processing are often lengthy and cause significant wear and tear on equipment, resulting in high equipment maintenance costs. The one-step grinding and polishing process provided in this application can save multiple surface processing steps, thereby significantly reducing equipment wear and maintenance frequency and extending equipment lifespan. Second, the optimization of the one-step grinding and polishing process also reduces the demand for high-cost polishing fluid 108 and polishing pads, further reducing material costs. Moreover, reducing processing steps also means shorter manual operation time, thereby reducing labor costs.

[0102] The surface finishing method provided in this application embodiment can also improve product quality. This surface finishing method can effectively remove surface damage introduced by cutting lines through a one-step grinding and polishing process, by optimizing the material of the processing liquid in the two-liquid supply system and the process parameters of different process stages, while avoiding the increase in surface roughness caused by over-processing.

[0103] The present application will now be further described with reference to specific embodiments and comparative examples. Those skilled in the art should understand that the following embodiments and comparative examples are for illustrative purposes only and should not be construed as limiting the scope of protection of the present invention.

[0104] Example 1

[0105] Silicon carbide crystals are cut into silicon carbide wafers with a thickness of 410 μm using multi-wire cutting. The initial thickness of the wafers is tested, and the surface processing equipment provided in this application is used to perform surface processing on the silicon carbide wafers. This surface processing equipment is equipped with a real-time thickness optical monitor as the aforementioned thickness detection device 114. The main body 100 of the surface processing equipment includes an upper polishing disc 112 and a lower polishing disc 113 arranged opposite to each other, with composite polishing pads 102 respectively disposed on the upper polishing disc 112 and the lower polishing disc 113. After cleaning the machine, the composite polishing pads 102 are attached and fixed to the upper polishing disc 112 and the lower polishing disc 113 respectively, and the composite polishing pads 102 are trimmed. 30 L of water-based additive 107 is added to the liquid tank 111 of the first liquid supply system 105, and 30 L of Si sol-gel abrasive polishing slurry 108 is added to the liquid tank 111 of the second liquid supply system 106. The circulation pumps 109 of the first liquid supply system 105 and the second liquid supply system 106 are turned on and stirred.

[0106] When starting surface processing on the silicon carbide wafer, the target thickness is set to 58 μm. The silicon carbide wafer is placed at processing station 101, and the equipment is started. Initially, the thinning thickness is 0, which is less than the target thickness. The controller activates the first liquid supply system 105 and deactivates the second liquid supply system 106, and the equipment performs surface thinning. When the thinning thickness reaches the target thickness and the abrasive layer 104 of the composite polishing pad 102 is completely removed, exposing the polishing pad substrate 103, the controller deactivates the first liquid supply system 105 and activates the second liquid supply system 106, switching to the surface polishing stage. After 3 hours of surface polishing, the silicon carbide substrate wafer is obtained.

[0107] After cleaning the silicon carbide substrate wafer, flatness was tested using an FM200 flatness tester, surface quality was inspected using a CS8520 surface quality tester, and surface roughness was tested using an AFM atomic force microscope. The test results are shown in Table 1 below.

[0108] Table 1

[0109] Where TTV is the total thickness variation, warp is the warp, Scratch Total is the total scratch length, and Ra(MAX) is the maximum roughness.

[0110] Comparative Example 1

[0111] Silicon carbide crystals were diced using multi-wire cutting to obtain silicon carbide wafers with a thickness of 410 μm. After double-sided rough grinding, 40 μm was removed from the wafer using single-crystal diamond polishing slurry and a 16B cast iron disc. The equipment was then cleaned, and the silicon carbide wafers were ultrasonically cleaned with alcohol. Next, 25 μm was removed using polycrystalline diamond polishing slurry and a polyurethane polishing pad with a TDP-1200 machine. The wafer's surface shape and thickness were tested using an SPI300 machine. Finally, the wafers were polished into wafers using a chemical mechanical polishing method, first with rough polishing and then with fine polishing. After cleaning, the wafers were tested using the same testing equipment as in Example 1. The test results are shown in Table 2 below.

[0112] Table 2

[0113] In Example 1 and Comparative Example 1, the silicon carbide wafers were obtained by processing coaxial crystals.

[0114] The test results in Tables 1 and 2 show that the wafer obtained by Example 1 using the surface processing equipment and surface processing method provided in this application is superior to Comparative Example 1 in terms of surface shape (TTV and warp), surface quality (Scratch Total), and surface roughness (RaMAX), and the total processing time is shorter. This proves that the wafer quality of the diced wafer is significantly improved and the processing efficiency is increased after processing with the present invention.

[0115] The various embodiments in this application are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical parts between embodiments can be referred to interchangeably. The embodiments provided in this application can be combined with each other without contradiction.

[0116] It should be noted that, in the description of this application, the accompanying drawings and embodiments are illustrative rather than restrictive. The same reference numerals throughout the embodiments identify the same structures. Additionally, for understanding and ease of description, the thicknesses of some layers, films, panels, regions, etc., may be exaggerated in the drawings. It is also understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element or there may be intermediate elements. Furthermore, "on" means positioning an element on or below another element, but does not inherently mean positioning it above another element according to the direction of gravity.

[0117] The terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the middle.

[0118] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0119] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A surface processing device for cutting discs, characterized in that, include: The machine body has a processing station for carrying the cutting disc to be processed; A composite polishing pad is disposed opposite to the processing station. The composite polishing pad includes a polishing pad base and an abrasive layer disposed on one side surface of the polishing pad base. The first liquid supply system is used to supply water-based additives to the processing station; The second liquid supply system is used to supply polishing liquid to the processing station; The controller is used to control the working status of the first liquid supply system and the second liquid supply system based on the thinning thickness of the cutting sheet to be processed after the processing equipment is started. When the thinning thickness is less than the set target value, the second liquid supply system is controlled to close and the first liquid supply system is controlled to open, so as to provide water-based additives to the processing station and perform surface thinning treatment on the cutting sheet to be processed. When the thinning thickness is not less than the set target value and the abrasive layer of the composite polishing pad is completely removed, the first liquid supply system is controlled to close and the second liquid supply system is controlled to open to provide polishing liquid to the processing station and perform surface polishing treatment on the cutting sheet to be processed.

2. The surface processing equipment for the cutting disc according to claim 1, characterized in that, The main body of the machine includes an upper polishing disc and a lower polishing disc arranged opposite to each other; each of the upper polishing disc and the lower polishing disc is fixed with a composite polishing pad, the abrasive layers of the two composite polishing pads are arranged opposite to each other, and the processing station is located between the two composite polishing pads; The main body of the machine also includes a lifting drive mechanism, which is connected to at least one of the upper polishing disc and the lower polishing disc, and is used to control the vertical height of at least one of the upper polishing disc and the lower polishing disc.

3. The surface processing equipment for the cutting disc according to claim 1, characterized in that, Also includes: A thickness detection device is used to detect the thinning thickness of the cut sheet to be processed.

4. The surface processing equipment for the cutting disc according to claim 3, characterized in that, The thickness detection device is based on a non-contact laser interferometry method, which uniformly selects multiple monitoring points on the surface of the cut sheet to be processed for thickness measurement.

5. The surface processing equipment for the cutting disc according to claim 1, characterized in that, The abrasive in the abrasive layer includes at least two different types of abrasive grains, and the abrasive grains of different materials have different grain sizes.

6. The surface processing equipment for the cutting disc according to claim 5, characterized in that, The polishing fluid includes silica gel abrasive particles, the particle size of which is smaller than the particle size of at least one abrasive particle in the abrasive layer.

7. The surface processing equipment for the cutting disc according to claim 5, characterized in that, The abrasive particles in the abrasive layer comprise agglomerated diamond micro powder and alumina particles; The agglomerated diamond micropowder accounts for a greater proportion of the mass of the alumina particles than the mass of the alumina particles, and the particle size of the agglomerated diamond micropowder is greater than the particle size of the alumina particles.

8. The surface processing equipment for the cutting disc according to claim 7, characterized in that, The mass ratio of the agglomerated diamond micro powder to the alumina particles is 3:2; The particle size of the agglomerated diamond micro powder is 5μm to 10μm; The alumina particles have a particle size of 0.1 μm to 1 μm.

9. The surface processing equipment for the cutting disc according to claim 1, characterized in that, The polishing pad substrate has a first grid groove on the side facing the abrasive layer; the composite polishing pad also includes a plurality of ventilation holes penetrating the polishing pad substrate; The surface of the abrasive layer has a second grid groove.

10. A surface processing method for a cutting disc, characterized in that, include: The cut piece to be processed is placed on the processing station of the surface processing equipment as described in any one of claims 1-9, and the cut piece to be processed is subjected to surface processing; During the surface processing of the cut sheet to be processed, the thinning thickness of the cut sheet to be processed is detected in real time; Based on the thinning thickness, the working states of the first liquid supply system and the second liquid supply system are controlled; wherein, when the thinning thickness of the cut sheet to be processed is less than the set target value, the second liquid supply system is turned off and the first liquid supply system is turned on to provide water-based additives to the processing station to perform surface thinning treatment on the cut sheet to be processed. When the thickness reduction of the cut sheet to be processed is not less than the set target value and the abrasive layer of the composite polishing pad is completely removed, the first liquid supply system is turned off and the second liquid supply system is turned on to provide polishing liquid to the processing station for surface polishing of the cut sheet to be processed.

11. The surface processing method for the cutting disc according to claim 10, characterized in that, During the surface processing of the cut sheet to be processed, the thinning thickness of the cut sheet to be processed is detected in real time, including: Based on a non-contact laser interferometry method, multiple monitoring points are uniformly selected on the surface of the cut sheet to be processed for thickness measurement.

12. The surface processing method for the cutting disc according to claim 10, characterized in that, Also includes: During the surface thinning process, when the thickness deviation of a local area of ​​the cut disc to be processed exceeds a set threshold, the grinding pressure and / or grinding speed of the local area are adjusted to reduce the thickness deviation.

13. The surface processing method for the cutting disc according to claim 10, characterized in that, The target value is set to be 25μm~100μm.

14. The surface processing method for the cutting disc according to claim 10, characterized in that, The surface polishing process takes 1 to 4 hours.

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