Polishing material, preparation method thereof, polishing method and sanding device

Abstract

The invention relates to the technical field of surface treatment, in particular to a polishing material, a preparation method thereof, a polishing method and a sanding device. The preparation method of the polishing material comprises the following steps that a polishing base material is subjected to at least one round of sanding rough machining through an abrasive belt till a rough machining semi-finished product with the glossiness of 15 GU to 20 GU is obtained; and the abrasive belt is used for conducting at least one round of sanding finish machining on the rough machining semi-finished product till the polishing material with the glossiness ranging from 50 GU to 55 GU is obtained. According to the polishing material, the same abrasive belt is utilized, the distance between the abrasive belt and the polishing base material and the distance between the abrasive belt and the rough machining semi-finished product are adjusted, the rough machining end point and the finish machining end point are judged according to the glossiness index, sanding of the polishing base material can be efficiently completed, and the prepared polishing material has good surface quality, has the high polishing rate on silicon wafers and is high in CMP machining efficiency.

Description

Technical Field

[0001] The present application relates to the field of surface treatment technology, and in particular to a polishing material and a preparation method thereof, a polishing method and a sanding device. Background Art

[0002] In recent years, the country has vigorously supported and developed the semiconductor industry through various policies in order to realize the localization and independence of the relevant industrial chain as soon as possible. One of the effective measures to promote the rapid and stable development of the semiconductor industry is to improve the manufacturing accuracy of semiconductor equipment. In the process of advanced semiconductor equipment, more than ten metal layers of products need to be processed. In order to ensure the interconnection efficiency between each metal layer, the surface processing quality requirements of the dielectric layer are becoming more and more stringent. Chemical mechanical polishing (CMP) is currently the only processing technology that can achieve global flattening of the dielectric layer surface. CMP combines chemical and mechanical methods to achieve high-precision flattening of the workpiece surface through the dual effects of chemical corrosion and mechanical grinding. Specifically, CMP uses relative movement between the wafer and the polishing pad under a certain pressure and in the presence of polishing liquid, and uses the mechanical grinding effect of nano-abrasives and the chemical corrosion effect of oxidants, catalysts, etc. to peel off the material from the wafer surface layer by layer, thereby achieving a highly flattened effect. It is very important to improve the processing efficiency of CMP.

[0003] CMP polishing materials, such as polishing pads, are one of the key consumables in the CMP polishing process. They are disc-shaped, mostly made of hard porous polyurethane foam, and have high-aspect ratio groove patterns. The polishing material provides an attachment point for the contact between the nanoabrasive and the wafer, and its surface is in direct contact with the wafer surface. The surface quality of the polishing material directly affects the CMP processing efficiency.

[0004] The surface quality of the polishing material mainly depends on the sanding process. In order to ensure that the surface quality of the polishing material produced meets the processing requirements of CMP, sanding belts of various mesh sizes are usually required to process it, resulting in low production efficiency of the sanding process. Summary of the invention

[0005] Based on this, the first aspect of the present application provides a method for preparing a polishing material, and its technical solution is as follows:

[0006] A method for preparing a polishing material comprises the following steps:

[0007] The polishing substrate is subjected to at least one round of rough sanding by using an abrasive belt to obtain a rough-processed semi-finished product with a glossiness of 15GU to 20GU, wherein each round of rough sanding independently comprises the following steps: adjusting the relative position of the abrasive belt and the polishing substrate so that the polishing substrate is subjected to one round of sanding by the abrasive belt;

[0008] The rough-machined semi-finished product is subjected to at least one round of sanding finishing by using the sanding belt to obtain a polished material with a glossiness of 50GU to 55GU, wherein each round of sanding finishing independently comprises the following steps: adjusting the relative position of the sanding belt and the rough-machined semi-finished product so that the rough-machined semi-finished product is subjected to sanding by the sanding belt once;

[0009] The reduction in the distance between the sand belt and the polished substrate when the polished substrate subjected to two adjacent rounds of rough sanding is subjected to the sand belt sanding is greater than the reduction in the distance between the sand belt and the rough-processed semi-finished product subjected to two adjacent rounds of fine sanding when the rough-processed semi-finished product is subjected to the sand belt sanding; wherein, the distance between the sand belt and the polished substrate refers to the distance between the side of the sand belt closest to the polished substrate and the side of the polishing substrate farthest from the sand belt, and the distance between the sand belt and the rough-processed semi-finished product refers to the distance between the side of the sand belt closest to the rough-processed semi-finished product and the side of the rough-processed semi-finished product farthest from the sand belt.

[0010] This application has the following beneficial effects:

[0011] The present application utilizes the same sanding belt, adjusts the distance between the sanding belt and the polishing substrate and the rough-processed semi-finished product, and determines the rough-processing and fine-processing end points according to the glossiness index, so as to efficiently complete the sanding of the polishing substrate, and the prepared polishing material has good surface quality, has a high polishing rate for silicon wafers, and has high CMP processing efficiency.

[0012] It can be understood that the rough-processed semi-finished product with a gloss of 15GU~20GU refers to the rough-processed semi-finished product with a gloss of 15GU~20GU on the sanded surface. Similarly, the polished material with a gloss of 50GU~55GU refers to the polished material with a gloss of 50GU~55GU on the sanded surface. The gloss of the sanded surface is measured by using a YG-336C strong light explosion-proof flashlight, 100mm away from the edge of the polished material, and emitting an incident light at an incident angle of 20°. The gloss meter is used to test the amount of reflected light of the incident light at the same angle, which is the gloss.

[0013] Optionally, the average thickness of the polishing substrate is recorded as T1, and in the first round of rough sanding, the relative position of the sand belt and the polishing material is adjusted so that when the polishing substrate is sanded by the sand belt, the distance between the sand belt and the polishing substrate is T1+0.1mm~T1+0.3mm. For example, the distance is adjusted to T1+0.1mm, T1+0.2mm, T1+0.3mm.

[0014] During the first round of rough sanding, the distance between the sand belt and the polishing substrate is larger than the average thickness of the polishing substrate, so that larger protrusions of the polishing substrate can be removed.

[0015] Rough sanding is mainly used for rapid processing, sanding out the top of the pores, and the two adjacent rounds of rough sanding have a greater adjustment on the reduction of the distance between the sand belt and the polished substrate. Optionally, in addition to the first round of rough sanding, the distance between the sand belt and the polished substrate in the Nth round of rough sanding is 0.02mm~0.06mm smaller than that in the N-1th round of rough sanding. For example, it is 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm smaller. Preferably, it is 0.03mm~0.05mm. The distance between the Nth round of rough sanding is smaller than that of the N-1th round, that is, as each round of rough sanding is carried out, the distance between the sand belt and the polished substrate is gradually reduced, and the polished substrate is subjected to sanding by the sand belt at a continuously reduced distance, which can ensure that the sanded surface has a suitable pore morphology, pore size and pore distribution without frequently replacing the sand belt. When the distance between the sanding belt and the polishing substrate in the Nth round of rough sanding is greater than 0.06 mm in the N-1th round of rough sanding, the machine may be overloaded and in a critical alarm state, affecting the life of equipment parts and processing quality.

[0016] Optionally, the number of rounds for rough sanding can be 1 to 20 rounds, for example, 1 round, 2 rounds, 3 rounds, 4 rounds, 5 rounds, 6 rounds, 7 rounds, 8 rounds, 9 rounds, 10 rounds, 11 rounds, 12 rounds, 13 rounds, 14 rounds, 15 rounds, 16 rounds, 17 rounds, 18 rounds, 19 rounds, and 20 rounds.

[0017] It is understandable that after each round of rough sanding, the glossiness of the sanded surface can be measured by the above method. The glossiness of the sanded surface can also be estimated. When the sanded surface after a round of rough sanding is estimated to be close to 15GU~20GU, the glossiness of the sanded surface can be measured again to reduce the number of times the machine is stopped to measure the glossiness. The method for estimating the glossiness of the sanded surface can be visual inspection under local strong light, such as visual inspection under a flashlight, bottom light mirror, or bright field spotlight.

[0018] The glossiness of the rough-processed semi-finished product is between 15GU and 20GU. At this time, most of the pores have been sanded through, and the surface state of the rough-processed semi-finished product is close to the sanding completion, and sanding finishing is carried out.

[0019] Optionally, the average thickness of the rough-machined semi-finished product is T2, and in the first round of sanding finishing, the relative position of the abrasive belt and the rough-machined semi-finished product is adjusted so that when the rough-machined semi-finished product is sanded by the abrasive belt, the distance between the abrasive belt and the rough-machined semi-finished product is T2-0.01mm~T2-0.03mm. For example, the distance is adjusted to T2-0.01mm, T2-0.02mm, T2-0.03mm.

[0020] During the first round of sanding finishing, the distance between the sanding belt and the rough-machined semi-finished product is set based on the average thickness of the rough-machined semi-finished product. This can prevent deviations in finishing caused by the rebound of the rough-machined semi-finished product during the glossiness testing process.

[0021] In the fine sanding process, the two adjacent rounds of rough sanding have a smaller adjustment on the distance between the sand belt and the polishing substrate than the rough sanding process, so as to avoid damaging the structure of the pores that have been sanded through, which corresponds to the phenomenon of uneven color on the surface of the polished material, and may even damage and crack the polished material, resulting in poor product quality or scrap.

[0022] Optionally, in addition to the first round of sanding finishing, the distance between the sanding belt and the rough-machined semi-finished product in the Nth round of sanding finishing is 0.01 mm to 0.03 mm smaller than that in the N-1th round of sanding finishing. The distance in the Nth round of sanding finishing is smaller than that in the N-1th round, that is, as each round of sanding finishing is performed, the distance between the sanding belt and the rough-machined semi-finished product is gradually reduced, and the rough-machined semi-finished product is sanded by the sanding belt at a continuously reduced distance, which can avoid frequent replacement of the sanding belt and ensure that the sanded surface has a suitable pore morphology, pore size and pore distribution.

[0023] Optionally, the number of rounds of sanding finishing can be 1 to 10 rounds, for example, 1 round, 2 rounds, 3 rounds, 4 rounds, 5 rounds, 6 rounds, 7 rounds, 8 rounds, 9 rounds, and 10 rounds.

[0024] It is understandable that after each round of sanding finishing, the glossiness of the sanded surface can be measured by the above method. The glossiness of the sanded surface can also be estimated. When the sanded surface after a round of rough processing is estimated to be close to 50GU~55GU, the glossiness of the sanded surface can be measured again to reduce the number of times the machine is stopped to measure the glossiness. The method for estimating the glossiness of the sanded surface can be visual inspection under local strong light, such as visual inspection under a flashlight, bottom light mirror, or bright field spotlight.

[0025] When preparing polishing materials by traditional sanding process, the mesh number of the sanding belt is used as the indicator of rough processing and fine processing, and the thickness of the product is used as the end point indicator of rough processing and fine processing. For example, when using a sanding belt with a lower mesh number, it is considered as rough processing and processing to a certain thickness. When changing to a sanding belt with a higher mesh number, it is considered as fine processing and processing to a certain thickness. The above method requires frequent shutdown to replace the sanding belt, the sanding continuity is poor, and the semi-finished product is prone to rebound during the shutdown to replace the sanding belt, resulting in processing deviation, and the efficiency is low. The present application can use the same sanding belt, and by continuously reducing the distance between the sanding belt and the polishing substrate or the rough-processed semi-finished product, sanding rough processing and sanding fine processing can be achieved respectively, and glossiness is used as the end point indicator of sanding fine processing and sanding rough processing, which can avoid continuous shutdown to replace the sanding belt, and has good sanding continuity, simple operation, less chance of semi-finished product rebound, high processing accuracy, high processing efficiency, and obtains a polishing material with suitable pore morphology, pore size and pore distribution, which is beneficial to the full contact between the polishing liquid and the silicon wafer, the reasonable storage and flow of the polishing liquid, and the timely discharge of debris during subsequent polishing.

[0026] Optionally, the mesh number of the abrasive belt is 120 mesh, 180 mesh, 240 mesh, 320 mesh, 400 mesh or 600 mesh. Preferably, the mesh number is 120 mesh, 240 mesh or 320 mesh.

[0027] Optionally, subjecting the polishing substrate to sanding with the abrasive belt once comprises the following steps:

[0028] The abrasive belt is arranged in a circle and rotated in a circle, and the polishing substrate is transferred from one side of the abrasive belt to the other side under the abrasive belt to complete one sanding.

[0029] Optionally, the rotation speed of the abrasive belt is 3m / s to 9m / s. For example, the rotation speed of the abrasive belt is 3m / s, 6m / s, or 9m / s. Preferably, the rotation speed is 3m / s to 8m / s. The abrasive belt can rotate under the drive of the roller, and can rotate clockwise or counterclockwise.

[0030] Optionally, the conveying speed of the polishing substrate is 5 m / min to 9 m / min. For example, the conveying speed is 5 m / min, 7 m / min, 9 m / min. Preferably, it is 6 m / s to 8 m / s. The polishing substrate can be conveyed from one side of the abrasive belt to the other side under the action of the guide roller.

[0031] Optionally, the rotating surface of the abrasive belt is parallel to the conveying direction of the polishing substrate.

[0032] Optionally, subjecting the rough-machined semi-finished product to sanding with the sanding belt once comprises the following steps:

[0033] The abrasive belt is arranged in a circle and rotated in a circle, and the rough-processed semi-finished product is transferred from one side of the abrasive belt to the other side below the abrasive belt to complete one sanding.

[0034] Optionally, the rotation speed of the abrasive belt is 3m / s to 9m / s. For example, the rotation speed of the abrasive belt is 3m / s, 6m / s, or 9m / s. The abrasive belt can rotate under the drive of the roller, and can rotate clockwise or counterclockwise.

[0035] Optionally, the conveying speed of the rough-machined semi-finished product is 5 m / min to 9 m / min. For example, the conveying speed is 5 m / min, 7 m / min, and 9 m / min. The rough-machined semi-finished product can be conveyed from one side of the abrasive belt to the other side under the action of the guide roller.

[0036] Optionally, the rotating surface of the abrasive belt is parallel to the conveying direction of the roughly machined semi-finished product.

[0037] The preparation method of the polishing material is suitable for processing multiple types and multiple batches of products.

[0038] Optionally, the polishing substrate comprises a porous polymer layer, a first bonding layer, a release layer, a second bonding layer and a back adhesive layer stacked in sequence. The side of the porous polymer layer away from the first bonding layer is a sanded surface. Optionally, the porous polymer layer is a porous polyurethane layer, which can be prepared by a wet synthetic leather method.

[0039] Optionally, the method for preparing the porous polymer layer comprises the following steps:

[0040] Mixing polyurethane resin and DMF to obtain a mixed solution;

[0041] The mixed liquid is coated on the base fabric and then placed in water. The solvent is replaced by water, and the polyurethane resin gradually solidifies to form a porous polymer layer.

[0042] Optionally, fillers and additives commonly used in the art may be added to the mixed liquid.

[0043] Optionally, the first bonding layer and the second bonding layer each independently include one or more of a pressure-sensitive curing adhesive and a hot-melt curing adhesive. The pressure-sensitive curing adhesive is formed by curing a pressure-sensitive adhesive, and the hot-melt curing adhesive is formed by curing a hot-melt adhesive. Optionally, the pressure-sensitive adhesive includes one or more of a polyacrylate pressure-sensitive adhesive, an acrylate pressure-sensitive adhesive, and a dimethyl terephthalate polymer pressure-sensitive adhesive. Optionally, the hot-melt adhesive includes one or more of a TPR hot-melt adhesive, an ethylene vinyl acetate hot-melt adhesive, a nylon hot-melt adhesive, a polyester hot-melt adhesive, a polyurethane hot-melt adhesive, and an epoxy resin hot-melt adhesive.

[0044] Optionally, the release layer includes a plastic release film, and the plastic release film includes one or more of a PET release film, a PE release film, a PMMA release film and a PVC release film.

[0045] Optionally, the adhesive layer is used to fit with the processing equipment disk surface for processing. The adhesive layer can be a double-sided adhesive tape, which can be selected from one or more of foam adhesive tape, substrate-free double-sided adhesive tape, PET double-sided adhesive tape and cloth-based adhesive tape.

[0046] A second aspect of the present application provides a polishing material, which is prepared by the above-mentioned preparation method.

[0047] The polishing material has suitable pore morphology, pore size and pore distribution, which is conducive to the full contact between the polishing liquid and the silicon wafer, the reasonable storage and flow of the polishing liquid, and the timely discharge of debris during subsequent polishing. The polishing material can be a polishing pad used in CMP processing.

[0048] The third aspect of the present application provides a polishing method, which includes the step of polishing an object to be polished using the above-mentioned polishing material.

[0049] In the above polishing method, the polishing material has suitable pore morphology, pore size and pore distribution, which is conducive to the full contact between the polishing liquid and the object to be polished, the reasonable storage and flow of the polishing liquid, and the timely discharge of debris during subsequent polishing, and the polishing efficiency is high. The above polishing method can be CMP.

[0050] Optionally, the material of the object to be polished includes one or more of silicon, sapphire and non-ferrous metals. For example, the object to be polished is a silicon wafer, an IC and the like.

[0051] The fourth aspect of the present application provides a sanding device, and its technical solution is as follows:

[0052] See also Figure 1 A sanding device 100 includes an abrasive belt 11, a roller 12, a workbench 13 and a lifting mechanism 14, wherein the abrasive belt 11 is sleeved on the roller 12, the roller 12 is located above the workbench 13, the workbench 13 is used to convey a polishing substrate and a rough-processed semi-finished product, and is connected to the lifting mechanism 14, and the lifting mechanism 14 is used to adjust the position of the workbench 13 and thus adjust the relative position of the abrasive belt 11 and the polishing substrate or the rough-processed semi-finished product;

[0053] The sanding device 100 of the present application adjusts the distance between the sanding belt 11 and the polishing substrate or the roughly processed semi-finished product through the lifting mechanism 14, which can avoid frequent replacement of the sanding belt and has a high processing efficiency.

[0054] Optionally, the lifting mechanism 14 includes a servo motor 141, a screw guide rail 142, a lifting nut 143 and a lifting shaft 144. The servo motor 141 is used to drive the screw guide rail 142 to rotate, push the lifting nut 143 to slide along the screw guide rail 142, and drive the lifting shaft 144 to rise and fall. The lifting shaft 144 is used to drive the workbench 13 to rise and fall.

[0055] Compared with the traditional lifting method of pneumatic cylinder or hydraulic cylinder, the lifting mechanism has higher lifting accuracy and can precisely control the distance between the sanding belt and the polishing substrate or the rough-processed semi-finished product during sanding, for example, it can achieve precise adjustment of the distance of 0.01mm.

[0056] Optionally, the roller 12 includes a first roller 121 and a second roller 122 that are spaced apart, and the abrasive belt 11 is sleeved on the outer roller rings of the first roller 121 and the second roller 122, and the abrasive belt 11 is driven to rotate in a circle by the rotation of the first roller 121 and the second roller 122. The first roller 121 and the second roller 122 rotate clockwise or counterclockwise around their respective axes, and the rotation speeds are kept consistent. The abrasive belt 11 is sleeved on the outer roller rings of the first roller 121 and the second roller 122, and fits tightly with the first roller 121 and the second roller 122. The first roller 121 and the second roller 122 are fixed in position during the processing, and after the equipment is started, the abrasive belt 11 rotates in a circle.

[0057] Optionally, the workbench includes a guide roller 131 and a support mechanism 132, wherein the guide roller 131 is used to provide the movement direction of the polishing substrate or the rough-processed semi-finished product, and the support mechanism 132 is used to support the movement of the polishing substrate or the rough-processed semi-finished product. The guide roller 131 rotates counterclockwise to drive the polishing substrate or the rough-processed semi-finished product to move from the right side to the left side of the sanding belt 11. The guide roller 131 rotates clockwise to drive the polishing substrate or the rough-processed semi-finished product to move from the left side to the right side of the sanding belt 11. Compared with the traditional lifting method of the pneumatic cylinder or the hydraulic cylinder, in the above-mentioned sanding device, the position of the guide roller 131 is stable, the distance between the sanding belt and the polishing substrate or the rough-processed semi-finished product is stable, the sanding uniformity is good, and the polishing substrate or the rough-processed semi-finished product is not easily damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0059] Figure 1 It is a structural schematic diagram of a sanding device according to one embodiment;

[0060] Figure 2 This is a schematic diagram of the roughness test partition;

[0061] Figure 3 The roughness test results of each embodiment and comparative example are statistically shown;

[0062] Figure 4 The polishing rate test results of each embodiment and comparative example are statistically shown;

[0063] Figure 5 The total sanding processing time results of each embodiment and comparative example are statistically shown. DETAILED DESCRIPTION

[0064] The present application will be further described in detail below in conjunction with specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly understood.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0066] the term

[0067] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0068] In the present application, the selection scope involving "and / or", "or / and", and "and / or" includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, and the any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items.

[0069] In the present application, "plurality", "multiple", "multiple times", "plurality", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0070] In this application, "optionally", "optional" and "optional" refer to optional, that is, to any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0071] In this application, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0072] In the present application, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the optional numerical distribution within the above numerical interval is deemed to be continuous and includes the two numerical endpoints of the numerical range (i.e., the minimum value and the maximum value), and every numerical value between the two numerical endpoints.

[0073] The following is further described in conjunction with specific embodiments and comparative examples. The raw materials involved in the following specific embodiments and comparative examples, unless otherwise specified, can all be commercially available, the instruments used, unless otherwise specified, can all be commercially available, and the processes involved, unless otherwise specified, are all routinely selected by those skilled in the art.

[0074] Example 1

[0075] This embodiment provides a sanding device, a polishing material and a preparation method thereof, the steps are as follows:

[0076] Step 1: Prepare Figure 1 The sanding device shown in the figure, wherein the mesh number of the sanding belt is 240 meshes. A polishing substrate is prepared, the polishing substrate is composed of a porous polyurethane layer, a polyacrylate pressure-sensitive adhesive, a PET release film, a polyacrylate pressure-sensitive adhesive and a foam adhesive tape stacked in sequence, and the side of the porous polyurethane layer away from the first bonding layer is the surface to be sanded, and the surface to be sanded is circular. The thickness of the polishing substrate at 9 points is measured with a micrometer, and the average value is taken as the initial thickness T1 of the polishing substrate, and T1 is measured to be 2.72 mm.

[0077] Step 2: Sanding rough processing

[0078] Place the polishing substrate on the workbench of the sanding device, and use the lifting mechanism to adjust the height of the workbench so that when the polishing substrate is subjected to belt sanding, the distance between the side of the belt closest to the polishing substrate and the side of the polishing substrate farthest from the belt is 2.77 mm. Turn on the roller to drive the belt to rotate (the speed is 8 m / s), and turn on the guide roller to transfer the polishing substrate from one side of the belt to the other side, completing one sanding and completing the first round of rough sanding.

[0079] The height of the workbench was adjusted by the lifting mechanism so that when the polished substrate was sanded with the sand belt, the distances between the side of the sand belt closest to the polished substrate and the side of the polished substrate farthest from the sand belt were 2.72 mm, 2.67 mm, 2.62 mm, 2.57 mm, 2.52 mm, 2.47 mm, 2.42 mm, 2.37 mm and 2.32 mm respectively. Other conditions were the same as those in the first round of rough sanding. Nine sandings were completed and nine rounds of rough sanding were completed to obtain a rough-finished semi-finished product with a glossiness of 20 GU.

[0080] Step 3: Sanding finishing

[0081] In order to prevent the springback of the rough-machined semi-finished product from causing deviation in the fine machining, a micrometer is also used to measure the thickness of the current rough-machined semi-finished product at 9 points, and the average is taken as the initial thickness T2 of the rough-machined semi-finished product. The measured T2 is 2.33 mm.

[0082] The height of the workbench is adjusted by the lifting mechanism so that when the rough-machined semi-finished product is subjected to belt sanding, the distance between the side of the belt closest to the rough-machined semi-finished product and the side of the rough-machined semi-finished product farthest from the belt is 2.31 mm. The roller is turned on to drive the belt to rotate (the speed is 8 m / s), and the guide roller is turned on to transfer the rough-machined semi-finished product from one side of the belt to the other side, completing one sanding and the first round of sanding finishing.

[0083] The height of the workbench is adjusted by the lifting mechanism so that when the rough-processed semi-finished product is subjected to belt sanding, the distances between the side of the belt closest to the rough-processed semi-finished product and the side of the rough-processed semi-finished product farthest from the belt are 2.29 mm and 2.27 mm respectively. Other conditions are the same as those in the first round of sanding and finishing. The secondary sanding is completed. After the second round of sanding and finishing, a polished material with a glossiness of 50 GU is obtained.

[0084] Example 2

[0085] This embodiment provides a sanding device, a polishing material and a preparation method thereof, the steps are as follows:

[0086] Step 1: Prepare Figure 1 The sanding device shown in the figure, wherein the mesh number of the sanding belt is 240 meshes. A polishing substrate is prepared, the polishing substrate is composed of a porous polyurethane layer, a polyacrylate pressure-sensitive adhesive, a PET release film, a polyacrylate pressure-sensitive adhesive and a foam adhesive tape stacked in sequence, and the side of the porous polyurethane layer away from the first bonding layer is the surface to be sanded, and the surface to be sanded is circular. The thickness of the polishing substrate at 9 points is measured with a micrometer, and the average value is taken as the initial thickness T1 of the polishing substrate, and T1 is measured to be 2.69 mm.

[0087] Step 2: Sanding rough processing

[0088] Place the polishing substrate on the workbench of the sanding device, and use the lifting mechanism to adjust the height of the workbench so that when the polishing substrate is subjected to the belt sanding, the distance between the side of the belt closest to the polishing substrate and the side of the polishing substrate farthest from the belt is 2.75 mm, turn on the roller to drive the belt to rotate (the speed is 8 m / s), and turn on the guide roller to transfer the polishing substrate from one side of the belt to the other side, completing one sanding and completing the first round of rough sanding.

[0089] The height of the workbench was adjusted by the lifting mechanism so that when the polished substrate was sanded with the sand belt, the distances between the side of the sand belt closest to the polished substrate and the side of the polished substrate farthest from the sand belt were 2.71 mm, 2.67 mm, 2.63 mm, 2.59 mm, 2.55 mm, 2.51 mm, 2.47 mm, 2.43 mm, 2.39 mm and 2.35 mm respectively. Other conditions were the same as those in the first round of rough sanding. Ten sandings and ten rounds of rough sanding were completed to obtain a rough-finished semi-finished product with a glossiness of 18 GU.

[0090] Step 3: Sanding finishing

[0091] In order to prevent the springback of the rough-machined semi-finished product from causing deviation in the fine machining, a micrometer is used to measure the thickness of the rough-machined semi-finished product at 9 points, and the average is taken as the initial thickness T2 of the rough-machined semi-finished product. The measured T2 is 2.35 mm.

[0092] The height of the workbench is adjusted by the lifting mechanism so that when the rough-machined semi-finished product is subjected to belt sanding, the distance between the side of the belt closest to the rough-machined semi-finished product and the side of the rough-machined semi-finished product farthest from the belt is 2.33 mm. The roller is turned on to drive the belt to rotate (the speed is 8 m / s), and the guide roller is turned on to transfer the rough-machined semi-finished product from one side of the belt to the other side, completing one sanding and the first round of sanding finishing.

[0093] The height of the workbench is adjusted by the lifting mechanism so that when the rough-machined semi-finished product is subjected to belt sanding, the distance between the side of the belt closest to the rough-machined semi-finished product and the side of the rough-machined semi-finished product farthest from the belt is 2.31 mm. Other conditions are the same as those in the first round of sanding and finishing. After one round of sanding and finishing, the second round of sanding and finishing is completed to obtain a polished material with a glossiness of 53GU.

[0094] Comparative Example 1

[0095] This comparative example provides a polishing material and a preparation method thereof, the steps are as follows:

[0096] Step 1: Sanding rough processing

[0097] exist Figure 1The first roller and the second roller of the sanding device shown are sleeved with a 120-mesh abrasive belt, and the polished substrate is the same as in Example 1. The height of the workbench is adjusted by the lifting mechanism, so that when the polished substrate is subjected to the abrasive belt sanding, the distance between the side of the abrasive belt closest to the polished substrate and the side of the polished substrate farthest from the abrasive belt is 2.77 mm, the roller is turned on to drive the abrasive belt to rotate (the speed is 8 m / s), and the guide roller is turned on to transfer the polished substrate from one side of the abrasive belt to the other side, completing one sanding, and completing the first round of sanding.

[0098] The height of the workbench is adjusted by the lifting mechanism so that when the polishing substrate is subjected to the belt sanding, the distances between the side of the belt closest to the polishing substrate and the side of the polishing substrate farthest from the belt are 2.71 mm and 2.62 mm respectively. Other conditions are the same as those of the first round of sanding. The secondary sanding is completed to complete the second round of sanding.

[0099] Step 2: Sanding and finishing

[0100] The machine was stopped, the 120-mesh abrasive belts were removed from the first and second rollers, replaced with 240-mesh abrasive belts, and the thickness of the polished substrate at 9 points was measured with a micrometer, with an average value of 2.62 mm. The height of the workbench was adjusted using a lifting mechanism so that when the polished substrate was sanded with the abrasive belts, the distances between the side of the abrasive belts closest to the polished substrate and the side of the polished substrate farthest from the abrasive belts were 2.58 mm, 2.54 mm, 2.5 mm, 2.46 mm, 2.42 mm, and 2.38 mm, respectively. Other conditions were the same as in the first round of sanding. Six sandings were completed, and six rounds of sanding were completed.

[0101] Step 3: Sanding finishing

[0102] The machine was stopped, the 240-mesh abrasive belts were removed from the first and second rollers, and replaced with 400-mesh abrasive belts. The thickness of the polished substrate at 9 points was measured with a micrometer, and the average value was 2.39 mm. The height of the workbench was adjusted using the lifting mechanism so that when the polished substrate was sanded with the abrasive belt, the distances between the side of the abrasive belt closest to the polished substrate and the side of the polished substrate farthest from the abrasive belt were 2.37 mm and 2.35 mm respectively. The rollers were turned on to drive the abrasive belts to rotate (the speed was 8 m / s), and the guide rollers were turned on to transfer the polished substrate from one side of the abrasive belt to the other side, completing the secondary sanding and the second round of sanding to obtain the polished material.

[0103] Comparative Example 2

[0104] This comparative example provides a sanding device, a polishing material and a preparation method thereof, which are basically the same as Example 1, except that step 2 and step 3 are different, as follows:

[0105] Step 2: Sanding rough processing

[0106] Place the polishing substrate on the workbench of the sanding device, and use the lifting mechanism to adjust the height of the workbench so that when the polishing substrate is subjected to belt sanding, the distance between the side of the belt closest to the polishing substrate and the side of the polishing substrate farthest from the belt is 2.77 mm. Turn on the roller to drive the belt to rotate (the speed is 8 m / s), and turn on the guide roller to transfer the polishing substrate from one side of the belt to the other side, completing one sanding and completing the first round of rough sanding.

[0107] The height of the workbench was adjusted by the lifting mechanism so that when the polished substrate was sanded with the sand belt, the distances between the side of the sand belt closest to the polished substrate and the side of the polished substrate farthest from the sand belt were 2.72 mm, 2.67 mm, 2.62 mm, 2.57 mm, 2.52 mm, 2.47 mm, 2.42 mm, 2.37 mm, 2.32 mm, and 2.27 mm, respectively. Other conditions were the same as those in the first round of rough sanding. Ten sandings and ten rounds of rough sanding were completed to obtain a rough-finished semi-finished product with a glossiness of 30 GU.

[0108] Step 3: Sanding finishing

[0109] In order to prevent the springback of the rough-machined semi-finished product from causing deviation in the fine machining, a micrometer is also used to measure the thickness of the current rough-machined semi-finished product at 9 points, and the average is taken as the initial thickness T2 of the rough-machined semi-finished product. The measured T2 is 2.28 mm.

[0110] The height of the workbench is adjusted by the lifting mechanism so that when the rough-machined semi-finished product is subjected to belt sanding, the distance between the side of the belt closest to the rough-machined semi-finished product and the side of the rough-machined semi-finished product farthest from the belt is 2.26 mm. The roller is turned on to drive the belt to rotate (the speed is 8 m / s), and the guide roller is turned on to transfer the rough-machined semi-finished product from one side of the belt to the other side, completing one sanding and the first round of sanding finishing.

[0111] The height of the workbench is adjusted by the lifting mechanism so that when the rough-processed semi-finished product is subjected to belt sanding, the distances between the side of the belt closest to the rough-processed semi-finished product and the side of the rough-processed semi-finished product farthest from the belt are 2.26 mm and 2.24 mm respectively. Other conditions are the same as those in the first round of sanding finishing. The secondary sanding is completed. After the second round of sanding finishing, a polished material with a glossiness of 55 GU is obtained.

[0112] Comparative Example 3

[0113] This comparative example provides a sanding device, a polishing material and a preparation method thereof, the main differences being:

[0114] Step 1: Prepare Figure 1The sanding device shown in the figure, wherein the mesh number of the sanding belt is 240 meshes. A polishing substrate is prepared, the polishing substrate is composed of a porous polyurethane layer, a polyacrylate pressure-sensitive adhesive, a PET release film, a polyacrylate pressure-sensitive adhesive and a foam adhesive tape stacked in sequence, and the side of the porous polyurethane layer away from the first bonding layer is the surface to be sanded, and the surface to be sanded is circular. The thickness of the polishing substrate at 9 points is measured with a micrometer, and the average value is taken as the initial thickness T1 of the polishing substrate, and T1 is measured to be 2.7 mm.

[0115] Step 2: Sanding rough processing

[0116] Place the polishing substrate on the workbench of the sanding device, and use the lifting mechanism to adjust the height of the workbench so that when the polishing substrate is subjected to the belt sanding, the distance between the side of the belt closest to the polishing substrate and the side of the polishing substrate farthest from the belt is 2.75 mm, turn on the roller to drive the belt to rotate (the speed is 8 m / s), and turn on the guide roller to transfer the polishing substrate from one side of the belt to the other side, completing one sanding and completing the first round of rough sanding.

[0117] The height of the workbench was adjusted by using the lifting mechanism so that when the polished substrate was subjected to belt sanding, the distances between the side of the belt closest to the polished substrate and the side of the polished substrate farthest from the belt were 2.69 mm, 2.63 mm, 2.57 mm, 2.51 mm, 2.45 mm, 2.39 mm, and 2.33 mm, respectively. Other conditions were the same as those in the first round of rough sanding. Seven sandings and seven rounds of rough sanding were completed to obtain a rough-finished semi-finished product with a glossiness of 25 GU.

[0118] Step 3: Sanding finishing

[0119] In order to prevent the springback of the rough-machined semi-finished product from causing deviation in the finishing process, a micrometer is used to measure the thickness of the rough-machined semi-finished product at 9 points, and the average value is taken as the initial thickness T2 of the rough-machined semi-finished product. The measured T2 is 2.34 mm.

[0120] The height of the workbench is adjusted by the lifting mechanism so that when the rough-machined semi-finished product is subjected to belt sanding, the distance between the side of the belt closest to the rough-machined semi-finished product and the side of the rough-machined semi-finished product farthest from the belt is 2.31 mm. The roller is turned on to drive the belt to rotate (the speed is 8 m / s), and the guide roller is turned on to transfer the rough-machined semi-finished product from one side of the belt to the other side, completing one sanding and the first round of sanding finishing.

[0121] The height of the workbench is adjusted by the lifting mechanism so that when the rough-processed semi-finished product is subjected to belt sanding, the distances between the side of the belt closest to the rough-processed semi-finished product and the side of the rough-processed semi-finished product farthest from the belt are 2.28 mm and 2.25 mm respectively. Other conditions are the same as those in the first round of sanding finishing. The secondary sanding is completed. After the second round of sanding finishing, a polished material with a glossiness of 60 GU is obtained.

[0122] The polishing materials prepared in the above embodiments and comparative examples were subjected to the following tests:

[0123] Project 1: Roughness test

[0124] The surface roughness values ​​of the polishing substrate and the polishing material are measured using a roughness detection instrument, and the detection instrument is a stylus-type roughness meter.

[0125] See also Figure 2 , the polishing substrate and the polishing material surface are divided into three areas: a straight line is drawn from the center of the material (the square material is the symmetry center) to the outer edge, and the straight line is intercepted at three points, namely c, m, and e. Equal diameter circles are drawn through the intersection points. The inner circular area is called area C, the middle circular area is called area M, and the outer circular area is called area E. One point is randomly selected from each area, a total of three points, and the average value is taken as the roughness measurement value of the polishing material. The distance from the center of point c accounts for 33% of the total length of the straight line, the distance between point c and point m accounts for 34% of the total length of the straight line, and the distance between point m and point e accounts for 33% of the total length of the straight line.

[0126] Project 2: Polishing rate test

[0127] Place the polishing material on the Japanese Ebara polishing machine, fit it tightly on the polishing disc surface, press it with a pressure head for 30 minutes, and then rinse, correct, and rinse for 10 minutes each. The polishing conditions are set as follows: polishing head 30rpm, polishing disc 30rpm, polishing pressure 28~30psi. Use B2176A polishing liquid, mix it with water at a ratio of 1:30, inject it into the machine, select the polishing liquid circulation mode, the flow rate is 4L / min, the object to be polished is a 12-inch silicon wafer, and a high-precision electronic scale is used to measure the current weight of the silicon wafer every 2 hours, calculate the difference and convert it into a polishing rate RR.

[0128] Project 3: Sanding efficiency test

[0129] A timer is used to record the total sanding processing time of the polishing material, including machine preparation time, routine sanding processing time, measurement time and other time (including changing the sanding belt, abnormal handling and cleaning and shutdown, etc.).

[0130] Roughness test results are shown in Figure 3, wherein p1 is the surface roughness value of the polished substrate (before sanding) and the polished material (after sanding) of Example 1, p2 is the surface roughness value of the polished substrate (before sanding) and the polished material (after sanding) of Example 2, d1 is the surface roughness value of the polished substrate (before sanding) and the polished material (after sanding) of Comparative Example 1, d2 is the surface roughness value of the polished substrate (before sanding) and the polished material (after sanding) of Comparative Example 2, and d3 is the surface roughness value of the polished substrate (before sanding) and the polished material (after sanding) of Example 3. Figure 3 It can be seen that the roughness of the polished substrate is mostly around 6~6.5μm, and there are different degrees of improvement after sanding. The roughness of the polished materials of Example 1 and Example 2 is mostly distributed in the range of 3.6~4μm, the roughness of the polished material of Comparative Example 1 is distributed in the range of 2.8~3μm, the roughness of the polished material of Comparative Example 2 is distributed in the range of 4.1~4.4μm, and the roughness of the polished material of Comparative Example 3 is distributed in the range of 4.8~5.1μm. The surface roughness of the materials after sanding in Comparative Example 2 and Comparative Example 3, which are rough-processed beyond the endpoint value, is higher than that in Example 1 and Example 2, which are rough-processed and fine-processed beyond the endpoint value. The surface roughness range of the material after sanding in Comparative Example 3, which uses a higher mesh sanding belt, is lower than that of the other cases. It can be seen that the processing exceeds the gloss endpoint value, resulting in an increase in material roughness, which does not meet the final roughness requirements of the product.

[0131] Polishing rate test results are shown in Figure 4 , wherein p1 is the polishing rate distribution of the polishing substrate and the polishing material of Example 1, p2 is the polishing rate distribution of the polishing substrate and the polishing material of Example 2, d1 is the polishing rate distribution of the polishing substrate and the polishing material of Comparative Example 1, d2 is the polishing rate distribution of the polishing substrate and the polishing material of Comparative Example 2, and d3 is the polishing rate distribution of the polishing substrate and the polishing material of Comparative Example 3. Figure 4 It can be seen that the silicon wafer polishing rate of Example 1 and Example 2 is better than that of Comparative Example 1, Comparative Example 2 and Comparative Example 3, indicating that the method of the embodiment can make the morphology, pore size and pore distribution of the pores on the surface of the polishing material after sanding, which is more conducive to the full contact between the polishing liquid and the silicon wafer during polishing, the reasonable storage and flow of the polishing liquid, and the timely discharge of debris.

[0132] The total sanding processing time test results are shown in Figure 5 , wherein p1 is the total sanding processing time test result of Example 1, p2 is the total sanding processing time test result of Example 2, d1 is the total sanding processing time test result of Comparative Example 1, d2 is the total sanding processing time test result of Comparative Example 2, and d3 is the total sanding processing time test result of Comparative Example 3. Figure 5It can be seen that the processing time of each embodiment is similar, and the total processing time of each embodiment is quite different from that of the comparative example 1. The main reason is that the sanding belts of different mesh sizes need to be replaced twice during the processing of the comparative example 1. Figure 3 , Figure 4 It can be seen that the performance of the polishing materials processed by Examples 1 and 2 is not significantly different from that of Comparative Example 1, and the processing time of a single piece is reduced by 20%: taking an order of 80 pieces in a batch as an example, based on an effective working time of 8 hours per day, it is estimated that 6.17 working days are required for processing using the process of Comparative Example 1, while the processes of Examples 1 and 2 can be completed in 5 days, which greatly shortens the production time and related operating costs.

[0133] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0134] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for preparing a polishing material, characterized in that: The following steps are involved: The polishing substrate is subjected to at least one round of rough sanding by using an abrasive belt to obtain a rough-processed semi-finished product with a glossiness of 15GU to 20GU, wherein each round of rough sanding independently comprises the following steps: adjusting the relative position of the abrasive belt and the polishing substrate so that the polishing substrate is subjected to one round of sanding by the abrasive belt; The rough-machined semi-finished product is subjected to at least one round of sanding finishing by using the sanding belt to obtain a polished material with a glossiness of 50GU to 55GU, wherein each round of sanding finishing independently comprises the following steps: adjusting the relative position of the sanding belt and the rough-machined semi-finished product so that the rough-machined semi-finished product is subjected to sanding by the sanding belt once; The reduction in the distance between the sand belt and the polished substrate when the polished substrate subjected to two adjacent rounds of rough sanding is subjected to the sand belt sanding is greater than the reduction in the distance between the sand belt and the rough-processed semi-finished product subjected to two adjacent rounds of fine sanding when the rough-processed semi-finished product is subjected to the sand belt sanding; wherein, the distance between the sand belt and the polished substrate refers to the distance between the side of the sand belt closest to the polished substrate and the side of the polishing substrate farthest from the sand belt, and the distance between the sand belt and the rough-processed semi-finished product refers to the distance between the side of the sand belt closest to the rough-processed semi-finished product and the side of the rough-processed semi-finished product farthest from the sand belt.

2. The method for preparing a polishing material according to claim 1, characterized in that: The average thickness of the polishing substrate is recorded as T1. In the first round of rough sanding, the relative positions of the sand belt and the polishing material are adjusted so that when the polishing substrate is sanded by the sand belt, the distance between the sand belt and the polishing substrate is T1+0.1mm~T1+0.3mm.

3. The method for preparing the polishing material according to claim 2, characterized in that: Except for the first round of rough sanding, the distance between the sanding belt and the polishing substrate in the Nth round of rough sanding is 0.02 mm to 0.06 mm smaller than that in the N-1th round of rough sanding.

4. The method for preparing the polishing material according to claim 3, characterized in that: The average thickness of the rough-machined semi-finished product is T2. In the first round of sanding finishing, the relative position of the sanding belt and the rough-machined semi-finished product is adjusted until the distance between the sanding belt and the rough-machined semi-finished product is T2-0.01mm~T2-0.03mm when the rough-machined semi-finished product is sanded by the sanding belt.

5. The method for preparing a polishing material according to claim 4, characterized in that: Except for the first round of sanding finishing, the distance between the sanding belt and the rough-machined semi-finished product during the Nth round of sanding finishing is 0.01 mm to 0.03 mm smaller than that during the N-1th round of sanding finishing.

6. The method for preparing a polishing material according to any one of claims 1 to 5, characterized in that: Subjecting the polishing substrate to sanding with the abrasive belt once comprises the following steps: The abrasive belt is arranged in a circle and rotated in a circle, and the polishing substrate is transferred from one side of the abrasive belt to the other side under the abrasive belt to complete a sanding operation; and / or The rough-machined semi-finished product is subjected to sanding by the sand belt once, comprising the following steps: The abrasive belt is arranged in a circle and rotated in a circle, and the rough-processed semi-finished product is transferred from one side of the abrasive belt to the other side below the abrasive belt to complete one sanding.

7. The method for preparing a polishing material according to claim 6, characterized in that: Includes at least one of the following features: (1) The rotation speed of the abrasive belt is 3m / s~9m / s; (2) The conveying speed of the polishing substrate is 5m / min~9m / min; (3) The conveying speed of the rough-processed semi-finished product is 5m / min~9m / min; (4) The rotating surface of the abrasive belt is parallel to the conveying direction of the polishing substrate; (5) The rotating surface of the abrasive belt is parallel to the conveying direction of the rough-machined semi-finished product; (6) The mesh size of the sanding belt is 120 mesh, 180 mesh, 240 mesh, 320 mesh, 400 mesh or 600 mesh.

8. A polishing material, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 7.

9. A polishing method, characterized in that: The method comprises the step of polishing an object to be polished using the polishing material according to claim 8; optionally, the material of the object to be polished comprises one or more of silicon, sapphire and non-ferrous metals.

10. A sanding device, characterized in that: It includes an abrasive belt, a roller, a workbench and a lifting mechanism, wherein the abrasive belt is sleeved on the roller, the roller is located above the workbench, the workbench is used to convey the polishing substrate and the rough-processed semi-finished product, and is connected to the lifting mechanism, and the lifting mechanism is used to adjust the position of the workbench and thus adjust the relative position of the abrasive belt and the polishing substrate or the rough-processed semi-finished product; Optionally, the lifting mechanism includes a servo motor, a lead screw guide rail, a lifting nut and a lifting shaft, wherein the servo motor is used to drive the lead screw guide rail to rotate, push the lifting nut to slide along the lead screw guide rail, drive the lifting shaft to move up and down, and the lifting shaft is used to drive the workbench to move up and down; Optionally, the roller comprises a first roller and a second roller which are spaced apart, the abrasive belt is sleeved on outer roller circles of the first roller and the second roller, and the abrasive belt is driven to rotate in a circle by the rotation of the first roller and the second roller; Optionally, the workbench includes guide rollers and a supporting mechanism, wherein the guide rollers are used to provide a movement direction for the polished substrate or the roughly machined semi-finished product, and the supporting mechanism is used to support the movement of the polished substrate or the roughly machined semi-finished product.

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