| 摘要 |
PURPOSE:To make it possible to prolong the service life of the grindstone so as to sharply eliminate the cost of a wafer machining, by forming said grindstone having a ring plate shaped base metal in which the plate thickness on the inner periphery side thereof is thinner than that on the outer periphery side, and the tapered angles at the right and left sides are similar within 1-20 deg. degrees. CONSTITUTION:In a thin ring plate shaped base metal 11 with a plate thickness of T=130mu, having a hole 12 at the center thereof, diamond, or CBN abrasive grain is fixed to the inner periphery edge part of the hole 12 and the vicinity thereof by a nickel plating or the like so as to form an abrasive grain layers 13. In this way, on the inner periphery sides of the flat surfaces 16, 17 of the base metal 11, taper surfaces 14, 15 are formed in such a manner as having similar angles alpha, beta to both sides thereof, within 1-20 degrees, thereby the arrangement of the abrasive grain layers 13 becomes symmetrical to a center line C and the length L3 thereof becomes extremely longer. Therefore, it is possible to prolong the service life of the grindstone and eliminate the cost of a wafer machining. |
