IC semiconductor industry is a high-tech industry with high investment and high output. Diamond grinding wheel is widely used in cutting, chamfering, polishing and thinning in IC industry chain. There is a big gap between domestic semiconductor diamond grinding wheel and foreign developed countries in terms of technology and product quality.

Mosuperhard is also trying our best, looking forward to a breakthrough in the semiconductor industry, the following is the case analysis of our diamond grinding wheel processing silicon materials.

Customer needs: processing silicon materials

Our conventional vitrified diamond grinding wheel is generally processed in accordance with the wet grinding adjustment formula. The customer said it was processed with silicon material. We provided our normal wet grinding wheel to the customer for the first time. Through our analysis, is used in wet grinding wheel if used in dry grinding, high temperature can cause the diamond Carbonization, and the holding of the binder force strong, the diamond into graphite, carbide between grinding wheel and workpiece to form a layer of graphite powder (grinding wheel surface can see a layer of black object) will produce skid, because diamond cannot fall off, can jam the porosity of grinding wheel. The temperature will further rise, forming a vicious cycle, the diamond keeps carbonizing, forming a layer of powder, grinding wheel and workpiece keep slipping, resulting in grinding immobile phenomenon.

The second time for the customer to adjust into dry grinding formula, particle size unchanged. The first step to reduce the concentration. The second is to add some carbon foundation powder to dissipate heat. The metal powder can speed up the cooling and at 400 ℃ can gasification part (part of sintering of gasification, gas hole), and in the process of dry grinding, grinding temperature will rise, carbon funds powder will further gasification, and formed a new hole, equivalent to form the two hole, one in the process of sintering, one in the process of grinding. Then reduce the content of the binder, so that its control force is weak, when the surface of the diamond passivation can quickly fall off, the formation of a new edge. According to the customer's feedback, the main problem of the grinding wheel this time is that the workpiece will have uniform tiny edge breakage (observed under the microscope), and the processed workpiece is grade B. This indicates that the diamond may be coarse, not caused by large particles (the edge collapse caused by large particles will not be uniform), and the particle size of the diamond needs to be adjusted.

The third experiment began. First of all, to reduce the particle size of diamond and the concentration, it is necessary to add some auxiliary materials and reduce the particle size of auxiliary materials. However, the screening standard of auxiliary materials in the market is not very strict, so it is necessary to treat the auxiliary materials to ensure the elimination of large particles in the auxiliary materials. After the particle size of diamond becomes fine, the bond chain between the binder and diamond will also change, that is, the contact area will further increase, so the sand ratio should be changed after the particle size becomes fine. At the same time, the content of carbon fund powder should be appropriately increased, and finally, the selection of diamond abrasive should try to choose some mellow raw materials and good concentration. Because customers require quality control of finish, edge breakage, cutting edge and so on. Customer feedback followed, the processing silicon material is completely without edge collapse, the finish is very good, basically need no dressing, and the ground out of the silicon chip completely meet the requirements of grade A products.

Moresuperhard had breakthrough in silicon grinding for the semiconductor industry.Vitrified diamond grinding wheel for dry grinding, from can not grind silicon material blank, need high frequency dreesing to fully grind silicon material but there are small side damage. Finally through the study of unremitting efforts, the technology department allocate vitrified diamond grinding wheel processing silicon material no collapse edge, degree of finish is very good, no need dressing. In addition, the silicon wafer completely meets the requirements of a-grade wafer, and the silicon material Nemesis "253" vitrified diamond grinding wheel has been successfully produced. It has been put into production and supplied to the market in bulk.

---EDITOR: Yun li/Jim

---POST: Doris Hu