Wafer actions cannot be observed in 4-way lapping because the carrier and wafer are sandwiched between the upper and lower plates. Therefore, the factors that affect the wafer actions during processing are unclear. In this study, the wafer actions were observed using an acrylic plate in place of the upper plate in a 4-way lapping machine. The results showed that the wafer rotated during lapping, but this rotation fluctuated considerably according to the position of the carrier. In addition, the lattice groove pitch of the plate or carrier material, etc., affected the wafer rotation. The effects of wafer rotation while held by the carrier on processing characteristics were then clarified experimentally.

Due to their hardness, cemented carbides and ceramics are commonly used to make cutting tools and mold dies. However, the wearing and trueing/dressing of the grinding wheel are critical problems for many manufacturers. Fine bubble (FB) coolant has been reported to decrease grinding force. However, there have been few reports regarding methods of generating FB by micropore ceramic. In this study, the density of FB, dissolved oxygen, and surface tension using a micropore FB generator were examined. The grinding force was effectively reduced by 15% compared with the current coolant.