公开(公告)号：US10352766B1

公开(公告)日：2019-07-16

申请号：US14965464

申请日：2015-12-10

Applicant: KLA-Tencor Corporation

Inventor： Barry Loevsky ,  Ari Krauss ,  Avraham Bakal

IPC: G01J1/00 ,  G01J1/42 ,  G02F1/135 ,  G02B26/08 ,  G02B26/04

Abstract: Focusing modules and methods are provided, which use a spatial light modulator (SLM) configured to yield a circumferentially sinusoidal pattern to derive focusing signals. For example, the SLM may comprise an optical chopper wheel made of a glass disc with a circumferentially sinusoidal pattern. The circumferentially sinusoidal pattern simplifies phase derivation from the focusing signal, providing a faster and more accurate estimation of defocusing. Signal detection may be carried out by a diode array that provides a more accurate signal faster, as well as a more differentiated analysis of the focusing signal than the one available by current technology.