# Study on Preparation and Processing Properties of Mechano-Chemical Micro-Grinding Tools
## 5 Performance Analysis of the Micro-Grinding Tools
### Micro-Grinding Performance
#### 5.2.2 Results and Discussion  
In this experiment, the self-made micro-grinding tools, diamond grinding tools of the same mesh and size, and commercially purchased silicon wafers processed by CMP were compared under the same process conditions, and the surface morphology was observed. Figure 13 shows the micromorphology comparison of the grinding area and the unground area of the silicon wafer processed under the ultra-depth microscope. It can be seen that the self-made micro-grinding tool can process the originally rough surface of the single-crystal silicon very smoothly. Figure 14 shows the surface topography of a silicon wafer ultra-depth of field microscope after using a diamond grinding tool, a self-made micro-grinding tool, and CMP processing. From the observation of Figure 14, it can be seen that the surface of the silicon wafer after diamond grinding tool processing shows very obvious processing traces and processing defects such as crushing and pits. The surface of the silicon wafer processed by self-made micro-grinding tools and CMP has no obvious processing scratches and no processing defects such as crushing, scratches, and pits. Figure 12: Actual view of the silicon wafer after processing. Figure 13: Micromorphology of single-crystal silicon grinding zone and unground area. The measurement results of surface roughness are shown in Figure 15. The measurement results showed that the surface of the silicon wafer, after the processing of self-made micro-grinding tools and diamond grinding tools, had a recognizable directional grinding texture. The measurement results showed that the surface roughness of silicon wafers after grinding self-made micro-grinding tools was Ra = 1.332 nm. In contrast, the surface roughness of silicon wafers after grinding diamond grinding tools was Ra = 96.363 nm, and the grinding effect of self-made micro-grinding tools was much better than that of diamond grinding tools. Analyzing the above phenomenon, it was found that the self-made micro-grinding tool was a soft reaction layer through the chemical reaction between the abrasive and the surface material of the silicon wafer. Then, the surface material was removed through the mechanical action between the abrasive and the silicon wafer to form an ultra-smooth and ultra-low damage silicon wafer surface. To explain the cause of the above phenomenon from a microscopic perspective, a scanning electron microscope picture of the abrasive was taken, as shown in Figure 16. The powder crushing that occurs during the abrasive grinding process causes the bonds of the crystals on the surface of the powder to break. Due to the formation of unsaturated atomic valence states, chemical reactions occur between two solids or the solid and the surrounding gases. The factors affecting the degree of solid-solid phase chemical reaction mainly include (1) the crystal lattice distortion or defect formation of solid under the action of mechanical force. (2) Through mechanical crushing into a fine powder, the solid surface energy is changed, and the specific surface area is increased by producing a new solid surface to improve the degree of the chemical reaction. (3) Under applied force, some atomic groups will be generated on the newly formed surface of the solid due to structural fragmentation, thereby improving the degree of the chemical reaction. The role of calcium oxide is to act as a curing agent to promote resin curing, and it has high bonding strength and heat resistance; adding an appropriate amount of calcium oxide can better  
Figure 14: Micromorphology of silicon wafer processed by different processing methods. (**a**) Diamond grinding tools processing. (**b**) Self-made micro-grinding tools processing. (**c**) CMP processing. Figure 15: Results of measuring surface roughness by a white light interferometer. (**a**) The machined surface of diamond grinding tools. (**b**) The machined surface of micro-grinding tools.