Patent Number: 6,166,392

Title: Exposure for performing synchronized off-axis alignment

Abstract: An exposure has at least two wafer pads for holding wafers at the same time to perform different tasks including exposing a wafer, aligning a wafer, and loading or unloading a wafer synchronously. The exposure of the invention includes an exposing unit, a wafer supporting unit and a alignment beam scan unit. The wafer-supporting unit contains at least two wafer pads for holding wafers. The alignment beam scan unit contains an interferometer for detecting the interference patterns formed by the alignment beams and the alignment marks on the wafers. The tasks of aligning a wafer, and exposing a wafer, or loading/unloading a wafer can be performed on the wafers placed on each individual wafer pad synchronously.

Inventors: Chang; Chih-Jen (Hsinchu, TW), Wu; Ming-Sung (Feng-Hsan, TW), Chen; Tseng-Lung (Hsinchu, TW)

Assignee: United Microelectronics Corp.

International Classification: G03F 9/00 (20060101); G03F 7/20 (20060101); G01N 021/86 ()

Expiration Date: 12/26/2017