TWI782178B

The purpose of the present invention is to enable a work table to be held without thinning in the center of a wafer after grinding. In the method for grinding a retaining surface, the grinding stone used is a ceramic grinding stone which has a ceramic binder and diamond abrasive grains mixed and sintered to be solidified to have pores on the grinding surface, and the grinding surface is formed in a ring shape without gaps in the grinding surface. The grinding method of the holding surface is to grind the holding surface by rotating the work table so that the grinding surface contacts the radius of the holding surface. Therefore, in the radius region, diamond abrasive grains can be embedded in a plurality of pores of the grinding surface, while the holding surface is ground, and when a gap is formed between the grinding surface and the holding surface by passing through the center of the holding surface, a recessed portion can be formed in the center of the holding surface by the diamond abrasive grains extrud