New Projection System for Optical Lithography Systems
Original Publication Date: 2002-Aug-25
Included in the Prior Art Database: 2003-Jun-21
Currently all Lithography machines (Steppers, Mask aligners) are working with a Mask, a Projection System transfers the image of the Mask onto the wafer. The mask contains the image which is desired on the wafer. To project the image onto the wafer in the desired position an alignment of the wafer is necessary: 1. The Stepper is searching for alignment marks on the wafer 2. If the alignment marks are found, the wafer is moved the desired position which has to be very precise (alignment step).