Composite layer method for minimizing PED effect

摘要

A novel composite layer structure method which is suitable for reducing post-exposure delay (PED) effects associated with fabricating a photolithography reticle or mask and eliminating or at least minimizing variations between intended and realized critical dimension values for a circuit pattern fabricated on the reticle or mask. The method includes providing a mask blank having a metal layer, providing a photoresist layer on the metal layer of the mask blank, providing a protective layer on the photoresist layer and photo-cracking the photoresist layer in the desired circuit pattern typically by electron beam exposure. During subsequent post-exposure delay periods, the protective layer prevents or minimizes Q-time narrowing of the photo-cracked photoresist, and consequently, prevents or minimizes narrowing of the critical dimension of a circuit pattern etched in the metal layer according to the width of the photo-cracked photoresist.