Wafer dicing blade sharpening plate and preparation method

Abstract

The application belongs to the technical field of wafer cutting, and particularly relates to a wafer scribing cutter grinding plate and a preparation method. The wafer scribing cutter grinding plate is prepared by hot-pressing molding of raw materials including the following mass percentages: resin liquid 14-20%, silicon carbide 72-78%, and resin binder 9-12%. The resin liquid is bisphenol A type epoxy resin liquid with an epoxy equivalent of 184-250 g / eq and a viscosity of 10000-40000 mPa.s at 25 DEG C. The resin binder is phenolic resin. The application significantly improves the uniformity of the internal structure of the grinding plate, so that the nickel layer can be more effectively removed and the diamond abrasive grains can be exposed when the scribing cutter is trimmed, thereby completely solving the occasional edge collapse problem in high-end wafer cutting.

Description

Technical Field

[0001] This invention belongs to the technical field of wafer dicing, specifically relating to a wafer dicing blade grinding plate and its preparation method. Background Technology

[0002] Wafer dicing is a critical process in the front-end of chip packaging, and its dicing precision directly affects chip yield, performance, and reliability. With the rapid development of the semiconductor industry, wafer manufacturing processes are evolving towards higher integration, miniaturization, and 3D stacking. Silicon wafer dicing kerfs are becoming increasingly narrow, and wafers diced with hard blades must be free of front-side chipping, back-side chipping, and wide kerf widths. As a core consumable, the sharpness and stability of the dicing blade are crucial for ensuring dicing quality. However, in high-speed, ultra-thin wafer dicing, the dicing blade is prone to wear and dulling, leading to defects such as edge chipping and cracks. There is an urgent need for efficient and precise blade repair using wafer grinding plates to extend tool life and reduce production costs. Currently, in the field of wafer grinding plate technology, domestically produced wafer grinding plates are mainly low-to-mid-range, and high-end wafer dicing cannot reach the level of imported products.

[0003] Existing technologies include research aimed at solving the problem of dicing blade trimming. For example, patent document CN115990842A discloses a method for preparing a grinding plate for a hub-type nickel-based dicing blade. This method uses phenolic resin as the main component and a small amount of silicon carbide combined with graphite. Although it can reduce the number of grinding passes to 16, the graphite component can easily cause insufficient uniformity in the grinding process. After trimming, the dicing blade still exhibits continuous back-side chipping when cutting silicon wafers, and the width of the dicing track is difficult to control within 25μm, which cannot meet the production specifications for high-end narrow-track wafers. For example, patent document CN117798840A discloses a dicing blade pre-cutting plate and its preparation method and application. It eliminates graphite and uses mixed silicon carbide powder of mixed particle size and compound resin powder (phenolic resin powder and epoxy resin powder) mixed and hot-pressed to form a certain degree of reduction in cutting path and elimination of chipping. However, it adopts a solid resin powder mixing process, and the uniformity of silicon carbide powder dispersion and coating is limited. Occasional edge chipping will occur under long-term batch processing. At the same time, the adaptability of fine-grained dicing blades still has shortcomings.

[0004] In summary, although existing technologies have explored and improved the dressing problem of dicing blades, from introducing graphite components to reduce grinding frequency to optimizing silicon carbide particle size distribution to improve cutting quality, current wafer grinding plates still face severe technical bottlenecks when dealing with the demands of high-end, ultra-thin, and narrow-track wafer dicing. On the one hand, while the introduction of soft components such as graphite reduces dressing difficulty, it sacrifices grinding uniformity and stability, leading to poor control of kerf width and persistent chipping. On the other hand, relying solely on solid resin powder mixing processes makes it difficult to achieve perfect dispersion and coating of ultra-fine silicon carbide powder, limiting the performance of the grinding plate in fine dressing and failing to completely eliminate occasional chipping defects. Therefore, a new technical solution is needed to address these technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a wafer dicing blade grinding plate and its preparation method, so as to solve the serious technical bottlenecks that current wafer grinding plates still face when dealing with the demand for high-end, ultra-thin and narrow-track wafer dicing, as mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following two technical solutions: Firstly, this invention provides a wafer dicing blade, which is hot-pressed from raw materials comprising the following mass percentages: 14-20% resin liquid, 72-78% silicon carbide, and 9-12% resin binder; wherein the resin liquid is a bisphenol A type epoxy resin liquid with an epoxy equivalent of 184-250 g / eq and a viscosity of 10000-40000 mPa·s at 25°C; the resin binder is a phenolic resin; and the silicon carbide has a particle size of W2.5, W1.5, or W1.

[0007] Secondly, this invention provides a method for preparing a wafer dicing blade grinding plate, characterized by comprising the following steps: S1. After baking the resin solution of the formula amount in an oven at 40℃ for 1-3 hours, mix it with the first solvent and stir until the system is transparent. Then add the second solvent and the formula amount of silicon carbide, and continue stirring until it becomes a paste. Spread it out and dry it. Then pass it through 60 mesh, 100 mesh and 200 mesh sieves in sequence to obtain the modified powder. The first solvent and the second solvent are both acetone. Based on the resin solution of the formula amount, the mass ratio of the first solvent to the second solvent is 70-90:200-300. S2. After refining the resin binder by sieving through a 200-mesh sieve, mix it evenly with the modified powder obtained in S1, and then sieve it through a 100-mesh sieve to obtain the mixed powder. S3. The mixed powder and grinding media are mixed in a three-dimensional mixer for 2-3 hours, and then ground to obtain a molding material; wherein, the mass ratio of the mixed powder to the grinding media is 1:2, and the grinding media is zirconium balls; S4. Fill the molding material into the mold and level it. Pass it through a temperature of 140-170℃ and a pressure of 120-150Kgf / cm. 2 The hot press is used to press the material at constant temperature and pressure for 50-70 minutes, and then the grinding plate blank is obtained by demolding. S5. The grinding plate blank is thinned and cut and shaped in sequence to finally obtain the finished wafer dicing blade grinding plate.

[0008] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses liquid bisphenol A epoxy resin as one of the main binders. Liquid resin has excellent flowability and wettability, and with the aid of the solvent, it can more fully and uniformly coat the surface of each silicon carbide particle, forming a dense resin film. This "liquid-phase coating" process fundamentally solves the technical problem of achieving perfect dispersion and coating of abrasive particles during solid powder mixing, ensuring a tighter bond and more stable performance among the components inside the grinding plate. This allows for efficient removal of the nickel layer from the dicing blade, precisely exposing the diamond abrasive grains and achieving an ideal sharpening effect. Ultimately, the dicing blades prepared by this grinding plate can completely solve the problems of occasional edge chipping and persistent back-side chipping during high-end wafer dicing, meeting the stringent production requirements of narrow dicing channels (e.g., within 25μm) and high yields (e.g., above 99%). This is a technical effect that cannot be achieved by existing solid resin powder mixing processes.

[0009] 2. This invention further precisely defines the epoxy equivalent (184–250 g / eq) and viscosity at 25°C (10,000–40,000 mPa·s) of the bisphenol A type epoxy resin liquid. The viscosity range of 10,000–40,000 mPa·s ensures good fluidity of the resin liquid, facilitating uniform mixing with the solvent and silicon carbide abrasive, while preventing separation of the resin and abrasive during subsequent drying due to excessively low viscosity, thus ensuring stable coating effect. The epoxy equivalent of 184–250 g / eq indicates suitable resin reactivity. When co-cured with a phenolic resin binder under hot pressing, a three-dimensional network structure with moderate cross-linking density and high mechanical strength is formed, firmly binding the silicon carbide abrasive together, making the grinding plate both wear-resistant and less prone to abrasive shedding when dressing dicing blades.

[0010] 3. This invention pre-dissolves the resin liquid in acetone until transparent, then mixes it with silicon carbide powder to form a paste. This allows the liquid resin to fully wet and uniformly coat each silicon carbide abrasive particle. Compared to the simple ball milling method of mixing solid resin powder and silicon carbide powder, the liquid-solid mixing method of this invention greatly improves the dispersion uniformity of ultrafine silicon carbide powder in the resin matrix, avoiding local abrasive gaps or enrichment caused by powder agglomeration. The cross-sectional electron microscope image of the grinding plate of this invention clearly shows that the resulting grinding plate has a uniform and dense internal structure, with silicon carbide particles effectively coated by the resin liquid, and the two are well combined. This uniform structure fundamentally ensures the balance of grinding force when dressing the dicing blade, avoiding inconsistent cutting edge dressing caused by uneven structure.

[0011] 4. This invention ensures consistent grinding performance of the grinding plate throughout its entire lifespan by fully coating silicon carbide with resin liquid and using a graded sieving process (60 mesh, 100 mesh, 200 mesh). The cutting comparison results in the examples clearly show that the dicing blade after being trimmed with the grinding plate of this invention no longer exhibits chipping on either the front or back sides, while the comparative grinding plate still shows back-side chipping after trimming. This fully demonstrates that this invention has achieved a breakthrough in eliminating occasional chipping defects.

[0012] 5. The process parameters in the preparation method of this invention have been systematically optimized: the resin liquid pretreatment conditions (baking at 40℃ for 1-3 hours) ensure good fluidity of the resin liquid; the two-step addition of acetone and the specific mass ratio (70-90:200-300) ensure sufficient dispersion of silicon carbide; the combination of mixing in a three-dimensional mixer for 2-3 hours and zirconium ball grinding media (mass ratio 1:2) ensures the uniformity of the molding material; the hot pressing molding conditions (140-170℃, 120-150 kgf / cm², holding pressure for 50-70 min) enable the grinding plate to obtain suitable strength and hardness while maintaining good grinding performance. The entire process is simple to operate and the parameters are controllable, making it suitable for large-scale industrial production and showing good prospects for industrial application. Attached Figure Description

[0013] Figure 1 This is an electron microscope image of the cross-section of the grinding plate in Embodiment 1 of the present invention; Figure 2 This is a cutting diagram before sharpening according to Embodiment 1 of the present invention; Figure 3 This is a cutting diagram showing the cutting process after sharpening, according to Embodiment 1 of the present invention. Figure 4 This is a cutting diagram before sharpening, shown in Comparative Example 1. Figure 5 This is a cutting display diagram after sharpening the tool, as shown in Comparative Example 1. Figure 6This is a diagram of the cutting edge of the dicing blade after sharpening according to Embodiment 1 of the present invention; Figure 7 This is a diagram of the cutting edge of the dicing blade after sharpening, as shown in Comparative Example 2. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to embodiments and comparative examples, but the embodiments of the present invention are not limited thereto. The raw materials used in the embodiments are all commercially available industrial products, wherein the epoxy equivalent of the bisphenol A type epoxy resin liquid is 184-250 g / eq, and the viscosity at 25°C is 10000-40000 mPa·s; the phenolic resin is a commercially available thermosetting phenolic resin powder; and the silicon carbide is green silicon carbide micro powder. Example 1:

[0015] This embodiment provides a wafer dicing blade, which is hot-pressed from the following raw materials in the indicated weight percentages: 15% bisphenol A type epoxy resin liquid, 73% W2.5 silicon carbide, and 12% phenolic resin. The preparation method is as follows: Step 1: Place the bisphenol A type epoxy resin liquid in a 40℃ oven and bake for 2 hours to reduce its viscosity; refine the phenolic resin powder by passing it through a 200-mesh sieve and set it aside.

[0016] Step 2: Weigh 27g of pretreated bisphenol A type epoxy resin solution and place it in a beaker. Add 80g of acetone (first solvent) and stir for 0.5h until the system is transparent and colorless.

[0017] Step 3: Transfer the above transparent solution into a large beaker, then add 300g of acetone (second solvent) and 147g of W2.5 silicon carbide, and stir for 1-2 hours until it becomes a paste.

[0018] Step 4: Spread the paste mixture evenly, dry it thoroughly, and then pass it through 60 mesh, 100 mesh, and 200 mesh sieves in sequence to obtain the modified powder.

[0019] Step 5: Mix the sieved modified powder with 22g of phenolic resin refined by 200-mesh sieve, and then sieve it through 100-mesh sieve to obtain the mixed powder.

[0020] Step 6: Place the mixed powder in a mixing tank, add 400g of zirconium balls (the mass ratio of mixed powder to zirconium balls is 1:2), mix in a three-dimensional mixer for 3 hours, and obtain the molding material after sieving.

[0021] Step 7: Fill the molding material into the 80mm×80mm mold according to the unit weight, smooth it with a scraper, put it into the hot press, press it at constant temperature and pressure at 140~170℃ and 120~150Kgf / cm², hold the pressure for 60min and then demold to obtain the grinding plate blank.

[0022] Step 8: Place the grinding plate blank in a double-end grinding machine to thin it to a thickness of 1.0mm, and then use a cutting machine to cut and shape it to 75mm×75mm, finally obtaining the finished wafer dicing blade grinding plate. Example 2:

[0023] This embodiment provides a wafer dicing blade, which is hot-pressed from the following raw materials in the following mass percentages: 15% bisphenol A type epoxy resin liquid, 73% W1.5 silicon carbide, and 12% phenolic resin.

[0024] The preparation method is the same as in Example 1, except that in step three, green silicon carbide micro powder with a particle size of W1.5 is used. The other steps and parameters are exactly the same as in Example 1. Example 3:

[0025] This embodiment provides a wafer dicing blade, which is hot-pressed from the following raw materials in the following mass percentages: 15% bisphenol A type epoxy resin liquid, 73% W1 silicon carbide, and 12% phenolic resin.

[0026] The preparation method is the same as in Example 1, except that in step three, green silicon carbide micro powder with a particle size of W1 is used. The other steps and parameters are exactly the same as in Example 1.

[0027] Comparative Example 1: This comparative example was prepared using the method described in the published patent document CN115990842A mentioned in the background art, as follows: Weigh out 6 parts of silicon carbide powder, 90 parts of phenolic resin and 3 parts of graphite, mix them in a ball mill for 1 hour, add the mixture into a mold and hot press it into shape, and then process it by conventional machining to obtain a grinding plate.

[0028] Comparative Example 2: This comparative example was prepared using the method described in the published patent document CN117798840A mentioned in the background art, as follows: Weigh 130g of W2.5 silicon carbide powder, 280g of W2 silicon carbide powder, 420g of phenolic resin powder, and 170g of epoxy resin powder, and ball mill them together (500rpm) for 2 hours. Add the mixed material to a mold and hot press it at 140-170℃ and 120-150Kgf / cm². Then, process it by conventional machining to obtain a dicing blade pre-cut plate.

[0029] The following are comparative tests of the sharpening plate performance in Examples 1-3 and Comparative Examples 1-2: The grinding plates obtained in Examples 1-3 and Comparative Examples 1-2 were subjected to grinding and wafer dicing tests using dicing blades of the same specification and batch (the dicing blades were existing products of the inventor). The grinding parameters were: spindle speed 30Krpm, feed rate 40mm / s, 17 cuts in total, and depth of cut 0.4mm. The wafer dicing blade cutting parameters were: wafer type 200μm bare silicon, spindle speed 30Krpm, feed rate 50mm / s, cutting step 0.3mm, and cutting depth into the film 0.02mm.

[0030] The test results are as follows: Figure 1 This is a cross-sectional electron microscope image of the grinding plate prepared in Embodiment 1 of the present invention. Figure 1 It can be seen that the resulting grinding plate has a uniform and dense internal structure, and the silicon carbide particles are effectively coated by the resin liquid. The two are well combined, and there is no obvious abrasive agglomeration or separation of resin and abrasive.

[0031] Figure 2 , Figure 3 The images show the cutting results before and after sharpening in Example 1. Figure 2 It is evident that the dicing blade used in the pre-grinding process exhibits significant edge chipping defects when cutting silicon wafers; after trimming with the grinding plate in Example 1 ( Figure 3 With the addition of a dicing blade, chipping on both the front and back sides of silicon wafers no longer occurs, resulting in a significant improvement in cutting quality.

[0032] Figure 4 , Figure 5 The images show the cutting results before and after grinding in Comparative Example 1. Comparative Example 1 also exhibits edge chipping defects before grinding. Figure 4 After being trimmed by the grinding plate in Comparative Example 1 ( Figure 5 The dicing blade still results in back-side chipping when cutting silicon wafers, which cannot meet the requirements of high-end wafer cutting.

[0033] Figure 6 , Figure 7 The images show the cutting edge diagrams of the dicing blades after sharpening in Example 1 and Comparative Example 2, respectively. The comparison reveals that the diamond exposure on the cutting edge of Example 1 is better. In actual use, the dicing blades sharpened by the Comparative Example 2 grinding plate failed to achieve the customer's requirement of an AOI scan yield of over 99% when cutting dummy wafers, and the cutting quality was unstable throughout its service life.

[0034] As can be seen from the above test results, the grinding plates prepared in Examples 1-3 of this invention, due to the use of liquid bisphenol A epoxy resin liquid to liquid-phase coat silicon carbide, ensure that the silicon carbide is uniformly dispersed and completely coated in the resin matrix. During grinding, this effectively removes the nickel layer of the dicing blade and precisely exposes the diamond abrasive grains. The dicing blades prepared by the grinding plates of this invention no longer exhibit front-side or back-side chipping when cutting silicon wafers, meeting the stringent production requirements of narrow dicing channels (within 25μm) and high yield (above 99%).

[0035] In contrast, the grinding plate of Comparative Example 1, due to the introduction of graphite components, has insufficient grinding uniformity, and the dicing blade still exhibits continuous back-side chipping when cutting silicon wafers after trimming; the grinding plate of Comparative Example 2 uses a solid resin powder mixing process, which limits the uniformity of silicon carbide powder dispersion and coating, resulting in occasional edge chipping under long-term batch processing, and the compatibility with fine-grained dicing blades is also a shortcoming.

[0036] In summary, this invention significantly improves the uniformity of the internal structure of the grinding plate by using a liquid resin coating process for silicon carbide. This allows for more effective removal of the nickel layer and exposure of diamond abrasive grains during the trimming of the dicing blade, thereby completely solving the problem of occasional edge chipping in high-end wafer cutting. The results are superior to existing technologies.

Claims

1. A wafer dicing blade, characterized in that, It is prepared by hot pressing of raw materials comprising the following mass percentages: 14-20% resin liquid, 72-78% silicon carbide, and 9-12% resin binder; wherein the resin liquid is a bisphenol A type epoxy resin liquid with an epoxy equivalent of 184-250 g / eq and a viscosity of 10000-40000 mPa·s at 25°C; and the resin binder is phenolic resin.

2. The wafer dicing blade according to claim 1, characterized in that, The silicon carbide has a particle size of W2.5, W1.5, or W1.

3. A method for preparing a wafer dicing blade according to any one of claims 1-2, characterized in that, Includes the following steps: S1. After pretreating the resin liquid of the formula amount, mix it with the first solvent and stir until the system is transparent. Then add the second solvent and the formula amount of silicon carbide, and continue stirring until it becomes a paste. Spread it out, dry it, classify and sieve it to obtain the modified powder. S2. Mix the pretreated resin binder with the modified powder obtained in S1 evenly, and then sieve to obtain the mixed powder. S3. Mix the powder with grinding media and grind it to obtain the molding material; S4. Fill the molding material into the mold and smooth it. Press it under constant temperature and pressure using a hot press, and demold it under pressure to obtain the grinding plate blank. S5. The grinding plate blank is thinned and cut and shaped in sequence to finally obtain the finished wafer dicing blade grinding plate.

4. The method for preparing a wafer dicing blade according to claim 3, characterized in that, In S1, the resin liquid needs to be baked in a 40℃ oven for 1 to 3 hours before mixing.

5. The method for preparing a wafer dicing blade according to claim 3, characterized in that, In S1, both the first solvent and the second solvent are acetone; based on the amount of resin liquid in the formula, the mass ratio of the first solvent to the second solvent is 70-90:200-300.

6. The method for preparing a wafer dicing blade according to claim 3, characterized in that, In S1, the paste mixture is dried and then sieved through 60 mesh, 100 mesh, and 200 mesh in sequence.

7. The method for preparing a wafer dicing blade according to claim 3, characterized in that, In S2, the resin binder is pre-refined by sieving through a 200-mesh sieve before mixing, and after being mixed with the modified powder, it is sieved through a 100-mesh sieve to obtain the mixed powder.

8. The method for preparing a wafer dicing blade according to claim 3, characterized in that, In S3, the mixed powder and grinding media need to be mixed in a three-dimensional mixer for 2 to 3 hours.

9. The method for preparing a wafer dicing blade according to claim 3, characterized in that, In S3, the mass ratio of the mixed powder to the grinding media is 1:2, and the grinding media is zirconium balls.

10. The method for preparing a wafer dicing blade according to claim 3, characterized in that, In S4, the pressing temperature of the hot press is 140–170℃, and the pressing pressure is 120–150 kgf / cm³. 2 The pressing and holding time is 50-70 minutes.

Images