公开(公告)号：US09903705B2

公开(公告)日：2018-02-27

申请号：US15206613

申请日：2016-07-11

Applicant: Samsung Electronics Co., Ltd.

Inventor： Kwang-soo Kim ,  Harutaka Sekiya ,  Kwang-jun Yoon ,  Sung-won Park ,  Young-duk Kim ,  Heon-ju Shin ,  Byeong-hwan Jeon

IPC: G01N21/00 ,  G01B11/00 ,  H01L21/68 ,  G01N21/95 ,  G01N21/956

CPC classification number: G01B11/002 ,  G01N21/9501 ,  G01N21/956 ,  G01N2201/121 ,  H01L21/681

Abstract: An automatic focus control apparatus includes a light detector, which receives light reflected by a surface of a wafer and generates a light reception signal based on the received signal, a controller, which generates a driving signal, the driving signal being one of a first signal and a second signal, the driving signal indicating whether to perform automatic focus control based on the light reception signal, a focus error corrector, which generates a focus error correction signal based on the driving signal, and a stage driver, which displaces a wafer stage supporting the wafer by adjusting the z-axis position of the wafer stage based on the focus error correcting signal if the driving signal is the first signal, and maintains the z-axis position of the wafer stage based on the focus error correction signal if the driving signal is the second signal.