The development of Cleaving — DBG + CMP process

摘要

As telecommunication equipment that supports high-level information networks is being made portable, the requirements for telecommunication equipment to be small and lightweight are becoming stricter. Thus, miniaturization of semiconductor devices is necessary, and wafer dicing and chip thinning technologies are important key technologies to achieve it. Wafers are thinned by mechanical in-feed grinding using a grindstone containing diamond particles, and wafers are divided by mechanical blade dicing using a diamond blade. However, mechanical processes using diamond grits leave damage such as chipping, saw mark or residual strain on chip surfaces; thus, chip strength decreases. At chip thicknesses of 50 to 200 µm, such damage has to be avoided. In this study, novel manufacturing process steps for thin semiconductor devices are followed. 1) Irradiating dicing lines of wafer with a laser instead of blade dicing 2) Laminating the wafer surface protective tape 3) Cleaving the wafer into chips 4) Grinding until the final thickness + 5 um, that is simular DBG 5) Mirror finishing by CMP 6) Tape mounting the wafer onto dicing tape or DAF (Die Attach Film) 7) Removing the wafer surface protective tape. We named these process steps Cleaving — DBG.