公开(公告)号：EP0209969B1

公开(公告)日：1991-07-24

申请号：EP86303919.4

申请日：1986-05-22

Applicant: VARIAN ASSOCIATES, INC.

Inventor： Turner, Norman Leonard ,  Pollock, John D.

IPC: H01J37/317 ,  H01J37/18

CPC classification number: H01J37/3171 ,  H01J37/18 ,  Y10S414/139

公开(公告)号：EP0209969A2

公开(公告)日：1987-01-28

申请号：EP86303919.4

申请日：1986-05-22

Applicant: VARIAN ASSOCIATES, INC.

Inventor： Turner, Norman Leonard ,  Pollock, John D.

IPC: H01J37/317 ,  H01J37/18

CPC classification number: H01J37/3171 ,  H01J37/18 ,  Y10S414/139

Abstract: The implantchamber pressure during ion implantation is controlled within a specified intermediate pressure range higher than the baseline pressure. Implanted dose errors resulting from neutralizing collisions of the beam with residual gas molecules are held constant and can be compensated. The pressure is maintained within the specified intermediate pressure range by a control system including a controllable vacuum valve associated with a vacuum pump, a chamber pressure sensor and a valve controller responsive to the pressure sensor. The valve controller opens and closes the valve to maintain the chamber pressure within the specified range after introduction of a wafer.