Finishing-free thinned grinding wheel and preparation method thereof

Abstract

The dressing-free thinning grinding wheel comprises a base and grinding teeth, the grinding teeth are installed on the base, and each grinding tooth comprises a main body part and a rapid consumption loose layer located at the tail end, away from the base, of the main body part. According to the trimming-free thinned grinding wheel provided by the embodiment of the invention, after a new grinding wheel is installed, a product to be machined can be directly ground and machined through the quick consumption loose layer, and due to the fact that the quick consumption loose layer is loose and has the porosity higher than that of the grinding tooth main body part, the quick consumption loose layer is quickly consumed while the grinding quality is not affected, and the grinding efficiency is improved. The included angle between the grinding surface of the grinding wheel and the plane of the to-be-machined product is rapidly reduced to zero, and the grinding surface of the grinding wheel is in complete contact with the to-be-machined product. The steps of installing a dressing plate and dressing the grinding wheel are not needed any more, and the production efficiency of the to-be-machined product thinning process can be improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor material processing technology, and in particular to a dressing-free thinning grinding wheel and its preparation method. Background Technology

[0002] As semiconductor integrated circuit transistor technology approaches its physical limits, the development direction of integrated circuits has increasingly focused on advanced packaging. The stacking of multilayer wafers using technologies such as TSV (Through Silicon Vias) and hybrid bonding is driving the rapid development of advanced packaging technologies. Therefore, in the fields of 2.5D and 3D packaging, wafer thinning is becoming increasingly important, with the final thickness after wafer thinning gradually reaching the micrometer level. Consequently, the demand for wafer thinning grinding wheels and the requirements for their technological sophistication are also increasing.

[0003] In the wafer thinning process, the procedure for changing the grinding wheel involves first removing the old grinding wheel and installing the new one. However, due to limitations in machine mounting accuracy and the dimensional accuracy of the grinding wheel itself, it's impossible for the grinding surface of the new wheel to perfectly align with the wafer's surface to be processed on the stage. This angle difference between the grinding surface and the wafer's surface results in a significant difference in roughness between the outer and central areas of the wafer, affecting the stability of the wafer thinning quality.

[0004] Therefore, a dressing plate specifically designed for dressing grinding wheels needs to be mounted on the stage first. Through mutual grinding between the new grinding wheel and the dressing plate, the angle between the new grinding wheel and the stage is eliminated. This ensures that the grinding surface of the grinding wheel makes complete contact with the surface of the wafer being ground during the next grinding step, thus guaranteeing the stability of the thinning process. However, the dressing operation for each new grinding wheel replacement is time-consuming, especially for grinding wheels with shorter lifespans that require frequent replacements. The grinding wheel replacement and dressing operations significantly impact production efficiency. Summary of the Invention

[0005] This application provides a dressing-free thinning grinding wheel and its preparation method to solve the problem that grinding wheel replacement and dressing affects production efficiency in related technologies.

[0006] In a first aspect, embodiments of this application provide a dressing-free thinning grinding wheel, comprising: Base; A grinding tooth, which is mounted on the base, and the grinding tooth includes a main body and a rapidly consumed loose layer located at the end of the main body away from the base.

[0007] In conjunction with the first aspect, in one embodiment, the density of the rapidly consumed loose layer is less than the density of the main body portion; And / or, the main body is made of the same material as the rapidly consumed loose layer.

[0008] In conjunction with the first aspect, in one embodiment, the density of the rapidly consumed loose layer is 40% to 70% of the density of the main body.

[0009] In conjunction with the first aspect, in one embodiment, the ends of the rapidly consumed loose layer are formed with an array of holes, spires, and / or grooves.

[0010] In conjunction with the first aspect, in one embodiment, the grinding teeth are arranged uniformly according to a preset shape; And / or, the length of the rapidly consumed loose layer perpendicular to the base is 10 μm to 20 μm; And / or, the base is made of steel or aluminum alloy; And / or, the base is circular or annular.

[0011] In conjunction with the first aspect, in one embodiment, the base is provided with a mounting groove, and one end of the main body is fixed in the mounting groove by an adhesive layer, the adhesive layer being formed by curing an adhesive.

[0012] In conjunction with the first aspect, in one embodiment, the adhesive is a thermosetting epoxy resin; And / or, the adhesive has a shear strength ≥20MPa, a curing temperature of 80℃~120℃, and a curing time of 1h~3h.

[0013] In conjunction with the first aspect, in one embodiment, the raw material of the grinding teeth comprises 40 to 60 parts diamond and 30 to 50 parts binder by weight, wherein the binder is selected from metal binders or ceramic binders.

[0014] In conjunction with the first aspect, in one embodiment, the metal binder contains one or more of Cu and Sn elements; And / or, the ceramic binder contains one or more of N2O, Al2O3, SiO2, B2O, GaO, and MgO; And / or, the diamond has a particle size of 0.2 μm to 40 μm.

[0015] Secondly, embodiments of this application provide a method for preparing a dressing-free thinning grinding wheel as described above, comprising: After the raw materials for grinding teeth are evenly mixed, they are pressed into shape and sintered in a vacuum furnace at 650℃~750℃ for 2h~5h to obtain grinding teeth. The grinding teeth are mounted on the base; The grinding teeth are laser-processed to form a rapidly consumed loose layer. The laser processing includes a laser pulse width of 300fs to 600fs, a laser wavelength of 700nm to 1200nm, and a laser power of 5W to 20W.

[0016] The beneficial effects of the technical solution provided in this application include: This application provides a dressing-free thinning grinding wheel and its preparation method. The dressing-free thinning grinding wheel provided in this application rapidly consumes its porous layer, allowing direct grinding of the workpiece after a new grinding wheel is installed. Because this rapidly consuming porous layer is porous and has a higher porosity than the main body of the grinding teeth, it is rapidly consumed without affecting the grinding quality. This causes the angle between the grinding surface of the grinding wheel and the plane of the workpiece to quickly decrease to zero, resulting in complete contact between the grinding surface of the grinding wheel and the workpiece. This application eliminates the need for a dressing plate and grinding wheel dressing steps, thereby improving the production efficiency of the workpiece thinning process. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a dressing-free thinning grinding wheel provided in an embodiment of this application; Figure 2 This is a side view of the dressing-free thinning grinding wheel in standby state, provided in an embodiment of this application. Figure 3 A top view schematic diagram of the working state of the dressing-free thinning grinding wheel provided in the embodiments of this application; Figure 4 This is a side view of the product to be processed during the initial contact of the dressing-free thinning grinding wheel provided in an embodiment of this application; Figure 5 This is a side view of the rapid wear and tear of the loose layer on the dressing-free thinning grinding wheel provided in the embodiments of this application; Figure 6 A three-dimensional view (pores) of the rapidly consumed loose layer provided in an embodiment of this application. Figure 7 A three-dimensional view (tower tip) of the rapidly consumed loose layer provided for an embodiment of this application. Figure 8 A three-dimensional view (groove) of the rapidly consumed loose layer provided in an embodiment of this application; Figure 9 This is a schematic diagram of the rapid consumption loose layer processing provided in the embodiments of this application.

[0019] In the diagram: 1. Base; 2. Grinding teeth; 21. Main body; 22. Rapidly consumed loose layer; 3. Adhesive layer; 4. Dressing-free thinning grinding wheel; 5. Mechanical / air-floating spindle; 6. Product to be processed; 7. Vacuum adsorption stage; 8. Laser; 9. Laser; 10. Rotary fixture. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] See Figure 1 As shown, this application provides a dressing-free thinning grinding wheel, which can solve the problem of grinding wheel replacement and dressing affecting production efficiency in related technologies.

[0022] First, the application scenarios of this application will be described. For example... Figure 2 As shown, the dressing-free thinning grinding wheel 4 of this application is mounted and fixed on the mechanical / air-float spindle 5. The high-speed rotation of the mechanical / air-float spindle 5 drives the dressing-free thinning grinding wheel 4 to rotate at high speed. The product to be ground 6, typically a semiconductor wafer substrate (Si, SiC, GaAs, InP, GaN, etc.) or an integrated circuit wafer, is placed on the vacuum adsorption stage 7. The product 6 is firmly adsorbed by the vacuum adsorption stage 7 and rotates along with it. The rotation direction of the vacuum adsorption stage 7 is consistent with that of the mechanical / air-float spindle. The rotation trajectory of the grinding teeth 2 of the dressing-free thinning grinding wheel 4 passes through the center of the product 6, as shown in the diagram. Figure 3 With the feed of the mechanical / air-bearing spindle 5, the product to be processed 6 can be thinned by planar grinding.

[0023] In this technological context, see Figure 1 As shown, the dressing-free thinning grinding wheel provided in this application includes a base 1 and grinding teeth 2. The base 1 is circular or annular and is made of steel or aluminum alloy, such as 6061-T6. It is machined to IT5 precision level by a multi-axis high-precision composite machine tool to ensure that the dynamic balance of the product at high speed meets the requirements. The grinding teeth 2 are mounted on the base 1 and include a main body 21 and a rapidly consumed loose layer 22 located at the end of the main body 21 away from the base 1.

[0024] Based on the aforementioned application scenario description, such as Figure 4As shown, after the dressing-free thinning grinding wheel 4 of this application is installed on the mechanical / air-float spindle 5, due to reasons such as the precision of the mechanical equipment and the installation precision, the grinding surface composed of the grinding teeth 2 and the workpiece 6 on the vacuum adsorption stage 7 inevitably have an angle α. Because the grinding teeth 2 have a rapidly worn loose layer 22, after the initial contact with the first workpiece 6, as the mechanical / air-float spindle 5 feeds towards the workpiece 6, the rapidly worn loose layer 22, being loose and having a larger porosity and lower bulk density compared to the main body 21, causes the rapidly worn loose layer 22 of the grinding teeth 2 that comes into contact with the workpiece 6 to be rapidly worn away. With the continuous feed of the mechanical / air-float spindle 5, by setting an appropriate rapidly worn loose layer height according to the actual wear ratio between the grinding wheel and the workpiece 6, the angle α can disappear before the first workpiece 6 is finished (e.g., ...). Figure 5 This allows the motion plane of the grinding tooth 2 to coincide with the plane of the product 6 to be processed, thus achieving the dressing-free gain effect of this application.

[0025] Therefore, the dressing-free thinning grinding wheel provided in this application allows for rapid consumption of its porous layer, enabling direct grinding of the product to be processed after the new grinding wheel is installed. Because this rapidly consuming porous layer is porous and has a higher porosity than the main body of the grinding teeth, it is consumed rapidly without affecting the grinding quality. This causes the angle between the grinding surface of the grinding wheel and the surface of the product to be processed to quickly decrease to zero, resulting in complete contact between the grinding surface of the grinding wheel and the product. This application eliminates the need for installing a dressing plate and performing a grinding wheel dressing step, thereby improving the production efficiency of the thinning process for the product.

[0026] The dressing-free thinning grinding wheel provided in this application embodiment works by utilizing the difference in porosity between the rapidly consumed loose layer 22 and the main body 21. This causes the rapidly consumed loose layer 22 to be consumed faster than the main body 21 during the grinding process. In other words, this application increases the porosity of the rapidly consumed loose layer 22 relative to the main body 21, thereby eliminating the included angle α through the rapid consumption of the rapidly consumed loose layer 22, while still allowing the main body 21 to perform normal grinding and thinning.

[0027] Furthermore, in some preferred embodiments, the main body 21 and the rapidly consumed loose layer 22 can be made of the same material or different materials, as long as the above principle is satisfied.

[0028] As a preferred example, the main body 21 is made of the same material as the rapidly consumed loose layer 22, which makes it easier to process.

[0029] Furthermore, the density of the rapidly consumed porous layer 22 is less than the density of the main body 21. Because the rapidly consumed porous layer 22 has a higher porosity, its density is lower than that of the main body 21. This allows it to be consumed more quickly during grinding.

[0030] As a preferred example, the density of the rapidly consumed loose layer 22 is 40% to 70% of the density of the main body 21.

[0031] It should be noted that even if the main body 21 and the rapidly consumed loose layer 22 are made of the same material, the density of the rapidly consumed loose layer 22 can be less than the density of the main body 21. This is because the calculation here is based on the overall volume, rather than excluding the volume occupied by the pores.

[0032] For example, see Figure 6 , Figure 7 and Figure 8 As shown, the end of the rapidly consumed loose layer 22 has an array of holes 221 ( Figure 6 ), Spire 222 ( Figure 7 ) and / or trench 223 ( Figure 8 ).

[0033] exist Figure 6 , Figure 7 and Figure 8 In this process, by machining holes 221, towers 222, or grooves 223 at the end of the grinding teeth 2, the porosity of the end portion can be increased, forming a rapidly consumed loose layer 22.

[0034] For example, the end portion of the grinding tooth 2 is processed. The initial density of the end portion is ρ0, the initial volume is V0, and the initial mass is m0. After processing, holes 221, towers 222, or grooves 223 are formed, resulting in a rapidly consumed loose layer 22. The density of the part of the end portion removed due to processing is ρ0, the volume is V1, and the mass is m1. At this time, the density of the rapidly consumed loose layer 22 is ρ2 = (m0-m1) / V0, not calculated according to V0-V1. This is because the density calculation in this application is based on the overall volume.

[0035] It is understandable that the above Figure 6 , Figure 7 and Figure 8 The structure shown is merely an example and can be processed into other structures to improve porosity according to actual needs.

[0036] Furthermore, the grinding teeth 2 are evenly arranged according to a preset shape; for example, see... Figure 3 As shown, the default shape is a circle, but this application can also arrange the shapes as needed.

[0037] Furthermore, the length of the rapidly consumed loose layer 22 perpendicular to the base 1 is 10μm to 20μm.

[0038] Further, see Figure 1 As shown, the base 1 is provided with an installation groove, and one end of the main body 21 is fixed in the installation groove by an adhesive layer 3, which is formed by curing an adhesive.

[0039] The adhesive is a thermosetting epoxy resin; the shear strength of the adhesive is ≥20MPa, the curing temperature is 80℃~120℃, and the curing time is 1h~3h, ensuring that the grinding teeth will not fall off during processing.

[0040] Further, by weight, the raw material for the grinding tooth 2 includes 40-60 parts diamond and 30-50 parts binder. During the preparation process, 5-10 parts of auxiliary materials can be added as needed. These auxiliary materials include at least one of a pore-forming agent and a lubricant. The specific proportions of the pore-forming agent and lubricant can be adjusted according to actual manufacturing requirements. The binder has a bending strength greater than 80 MPa and a coefficient of thermal expansion close to that of diamond, ensuring sufficient holding force for the diamond. The binder is selected from metal binders or ceramic binders.

[0041] The metal binder contains one or more of Cu and Sn elements.

[0042] The ceramic binder is prepared by the sol-gel method and its main components include one or more of N2O, Al2O3, SiO2, B2O, GaO, and MgO.

[0043] The diamond has a particle size of 0.2 μm to 40 μm. Preferably, the diamond has a particle size of 1 μm to 3 μm.

[0044] This application also provides a method for preparing a dressing-free thinning grinding wheel, which includes: 101: After uniformly mixing the raw materials for grinding teeth 2, press them into shape and sinter them in a vacuum furnace at 650℃~750℃ for 2h~5h to obtain grinding teeth 2.

[0045] 102: Install the grinding teeth 2 onto the base 1.

[0046] 103: The grinding teeth 2 are laser-processed to form a rapidly consumed loose layer 22. The laser processing includes a laser pulse width of 300fs to 600fs, a laser wavelength of 700nm to 1200nm, and a laser power of 5W to 20W.

[0047] By using femtosecond fast laser to perform laser etching cold processing on the end of the grinding tooth, it can rapidly consume the loose layer with structures such as holes 221, towers 222 or grooves 223, without negatively affecting other unprocessed areas of the grinding tooth.

[0048] As an example, see Figure 9 As shown, the cured grinding wheel is placed on the rotating jig 10, and the laser 9 generated by the laser 8 is aimed at the area to be processed at the end of the grinding teeth 2. The rotational speed and displacement speed of the rotating jig 10 and the laser 8 are controlled by the computer center, as well as the processing time of the laser 9. For example, the processing time for a hole is 10 to 30 seconds. The processing time can be adjusted according to different processing sizes. The laser pulse is 300 to 600 fs, the laser wavelength is 700 nm to 1200 nm, and the laser power is 5 W to 20 W. The grinding teeth 2 are then processed to create an area such as... Figure 6 The holes 221 shown form a rapidly consumed loose layer 22. The depth of the holes 221 in the rapidly consumed loose layer 22 is 10-20 μm, the diameter of the holes 221 is 50-150 μm, and the overall density of the rapidly consumed loose layer 22 is 40%-70% of the overall density of the main body 21. After all the grinding teeth 2 are processed, the production of the product of this application is completed.

[0049] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0050] It should be noted that in this application, 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 a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, 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 process, method, article, or apparatus that includes said element.

[0051] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement 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 claimed herein.

Claims

1. A dressing-free thinning grinding wheel, characterized in that, It includes: Base (1); A grinding tooth (2) is mounted on the base (1) and the grinding tooth (2) includes a main body (21) and a rapidly consumed loose layer (22) located at the end of the main body (21) away from the base (1).

2. The dressing-free thinning grinding wheel as described in claim 1, characterized in that: The density of the rapidly consumed loose layer (22) is less than the density of the main body (21); And / or, the main body (21) is made of the same material as the rapidly consumed loose layer (22).

3. The dressing-free thinning grinding wheel as described in claim 2, characterized in that: The density of the rapidly consumed loose layer (22) is 40% to 70% of the density of the main body (21).

4. The dressing-free thinning grinding wheel as described in claim 2, characterized in that: The end of the rapidly consumed loose layer (22) is formed with an array of holes (221), spires (222) and / or grooves (223).

5. The dressing-free thinning grinding wheel as described in claim 1, characterized in that: The grinding teeth (2) are evenly arranged according to a preset shape; And / or, the length of the rapidly consumed loose layer (22) perpendicular to the base (1) is 10 μm to 20 μm; And / or, the base (1) is made of steel or aluminum alloy; And / or, the base (1) is circular or annular.

6. The dressing-free thinning grinding wheel as described in claim 1, characterized in that: The base (1) is provided with an installation groove, and one end of the main body (21) is fixed in the installation groove by an adhesive layer (3), which is formed by curing an adhesive.

7. The dressing-free thinning grinding wheel as described in claim 6, characterized in that: The adhesive used is a thermosetting epoxy resin; And / or, the adhesive has a shear strength ≥20MPa, a curing temperature of 80℃~120℃, and a curing time of 1h~3h.

8. The dressing-free thinning grinding wheel as described in claim 1, characterized in that: The raw material of the grinding teeth (2) by weight includes 40 to 60 parts diamond and 30 to 50 parts binder, wherein the binder is selected from metal binders or ceramic binders.

9. The dressing-free thinning grinding wheel as described in claim 8, characterized in that: The metal binder contains one or more of Cu and Sn elements; And / or, the ceramic binder contains one or more of N2O, Al2O3, SiO2, B2O, GaO, and MgO; And / or, the diamond has a particle size of 0.2 μm to 40 μm.

10. A method for preparing a dress-free thinning grinding wheel as described in any one of claims 1 to 9, characterized in that, It includes: After the raw materials for the grinding teeth (2) are evenly mixed, they are pressed into shape and sintered in a vacuum furnace at 650℃~750℃ for 2h~5h to obtain the grinding teeth (2). The grinding teeth (2) are mounted on the base (1); The grinding teeth (2) are laser-processed to form a rapidly consumed loose layer (22). The laser processing includes a laser pulse width of 300fs to 600fs, a laser wavelength of 700nm to 1200nm, and a laser power of 5W to 20W.

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