EXPOSURE AND FOCUS SCALES FOR OPTICAL LITHOGRAPHY
Original Publication Date: 1987-Oct-01
Included in the Prior Art Database: 2001-Oct-24
In checking the critical dimensions (CDs) of a resist image for IC's it is desirable to be able to use the same optical microscope that is used for checking alignment and other aspects of after development inspec- tion. Since this procedure may be unreliable for CDs less than about 1 micrometer, indirect methods for CD inspection are needed. We have invented a new indirect method of CD inspection for optical lithography.