The polishing of the silicon block surface is directly related to the quality of silicon wafer cutting. In the polishing process, the silicon block is polished successively through a coarse grinding wheel and a fine grinding wheel. The function of the coarse grinding wheel is to cut the damaged layer on the surface of the silicon block; the function of the fine grinding wheel is to polish and remove the traces of the damaged layer and coarse sand on the surface of the silicon block.
1. Current status
The monocrystalline silicon wafer workshop opens a machine to accelerate laser cutting. If the operator is slightly careless during the actual work, the quality of the laser cutting of the silicon block will be poor. The main points are: there are saw marks on the surface of the laser-cut silicon block; the size of the silicon block is "bulging" in the middle; the shape of the local silicon block is bent due to disconnection. At present, the brush grinding wheel in the workshop can no longer completely remove the saw marks caused by laser cutting; for the "bulging belly" silicon block, due to the limited polishing ability of the brush grinding wheel, it cannot remove the large size in the middle. At this time, there is an urgent need for a grinding wheel with stronger grinding ability.
2. Implement strategy
The main principle of the polishing machine currently used in the workshop is to polish the surface of the silicon block through a coarse grinding wheel and a fine grinding wheel. At present, the coarse grinding wheel of the polishing machine is replaced by a diamond grinding wheel, and the fine grinding wheel uses a brush grinding wheel to polish the silicon block.
The experiment uses a diamond resin bonded grinding wheel. All natural artificial diamonds can be used for cutting. Diamond is an extremely strong form of carbon. It is amphiphilic to iron and causes rapid damage. The bonding agent is epoxy resin. Type binder has a certain damping effect on vibrations caused by friction in life. Using the strong grinding power of the diamond grinding wheel, some surface problems of the silicon block caused by the cutting machine can be eliminated, such as: there are saw marks on the surface of the silicon block cut by the laser; the size of the silicon block is "bulging" in the middle; Good results can be achieved by bending the shape of the local silicon block caused by the break, performing basic polishing, and then using a fine grinding wheel to improve the surface of the silicon block.
