Image Number 9 for United States Patent #7189498.
The present invention provides methods and apparatus for accomplishing a strong phase shift direct write lithography process using reconfigurable optical mirrors. A maskless lithography system is provided. The maskless direct-write lithography system provided uses an array of mirrors configured to operate in a tilting mode, a piston-displacement mode, or both in combination. The controlled mirror array is used to generate strong phase shift optical patterns which are directed onto a photoimageable layer of a substrate in order to facilitate pattern transfer. In order to avoid constraining the system to forming edges of patterns aligned with the array of mirrors, gray-scale techniques are used for subpixel feature placement.