| 摘要 |
A method for fabricating a photomask processes photoresist overlying a conductive pattern into a conformal and hardened material that is not stripped off but rather becomes an optical and structural component of the photomask. As such, the photoresist optically defines the dimension of critical features. This eliminates the dimensional uncertainty that arises from etching of the underlying conductive material. Further, a major source of defects in known photomasks is eliminated because the magnitude of the etch undercut no longer needs to be precariously minimized. The photoresist's thickness and optical transmission, where the photoresist extends into openings in the conductive pattern can be selected to allow a phase shift of transmitted light so that the photomask is a rim shifter phasemask. The conductive layer facilitates patterning of the photoresist using electron-beam pattern generation equipment and can be thinner than chrome layers in conventional photomasks.
|
