By preventing warping of chips when detaching individual chips from a dicing sheet, improvement in quality without cracks and in productivity is realized. A collet (115) used in a step of detaching chips (110) discretely divided as bonded to a dicing sheet (109) from the dicing sheet has a flat attraction surface made of a porous material of a size equal to or larger than the chip size. Alternatively, the collet may have a chip attraction groove containing poles, balls or hemispheres, for example, to prevent warping of chips. In the step of detaching each chip from the dicing sheet, a means for reducing the bonding force of the dicing sheet, such as heating device or cooling device, may be provided. Thus, warping or cracking can be prevented in a process of thinned semiconductor substrate. Additionally, since the means for reducing the bonding force of the dicing sheet is provided in a semiconductor manufacturing equipment, breakage or cracking of chips can be prevented more reliably.