公开(公告)号：JPH0621206A

公开(公告)日：1994-01-28

申请号：JP9569893

申请日：1993-04-22

Applicant: IBM

Inventor： JIYOOJI UIRIAMU DOTSURE ,  OGURA SEIKI ,  NIBUO ROBUEDO

IPC: H01L21/304 ,  H01L21/306 ,  H01L21/3105 ,  H01L21/321 ,  H01L21/76 ,  H01L21/762 ,  H01L27/12

Abstract: PURPOSE: To maintain the precision of the thickness of a grinding gage by stopping oxidization, when all the polysilicon has been converted into oxide at the time of forming device layers with certain intervals on an SOI wafer, and making a mesa thin, until it is equal to the height of the upper face of new oxide by chemical machinery type grinding. CONSTITUTION: An oxide layer 20 is provided on a bulk silicon substrate 10, and an epitaxial single-crystal device layer 30 is separated into a pair of mesas 40 by a pair of narrow trenches surrounding the maser and extending to the oxide layer 20, and a trench 32 is provided with an oxide bottom face. A pair of maser-separating trenches 32 are set, so as to be small such that the device intensity on a integrated circuit can be minimized, and a wide region such as a trench 35 can be prevented from tissing-processed. The thickness of the mesa 40 is decreased so as to be controlled precisely, and grinding is continued until the thickness of the mesa can equal the gate thickness of a layer 45, by using a layer equipped with two functions for precisely controlling the thickness for holding the upper face of a wafer to be flat.