METHOD OF DEVELOPING RELIEF IMAGES IN A PHOTORESIST LAYER

摘要

The invention relates to a method of developing relief images in a photoresist layer. The conformable masking techniques of the present invention can be successfully made and used in a practical manufacturing environment while providing increased resolution of photolithographic images while eliminating all manner of defects that might presently be encountered in the masks currently used in the semiconductor industry.
A body (10, 11) is first coated with a positive photoresist (12) overcoated with a conformable mask (13) which is exposed through a fixed mask (14) and developed to define a replica of the fixed mask, together with all its defects (18). The underlying photoresist (12) is then exposed to light through developed openings (20) in the conformable mask (13). The conformable mask (13) is then stripped and a new conformable mask (25) laid down. This new conformable mask (25) is now exposed through a second fixed mask (26) having the same image as the first fixed mask, but presumably with different defects (28) and developed to define a replica of the second mask. The underlying photoresist (12) is again exposed through the second conformable mask and developed. As a result of using two independently defined conformable masks clear image defects (18, 28) in the fixed masks (14, 26) are prevented from being reproduced in the underlying photoresist (12) and are not doubly exposed. Only desired regions (23, 33) in the underlying photoresist (12) are doubly exposed.