TW367583B - Forming method for contact/via with hard mask - Google Patents

Abstract

A kind of forming method for contact/via with hard mask. The used forming method for contact/via is to employ the photo-resist pattern as the mask for etching. But as the miniaturization of components, the thickness of photo-resist should be reduced to adapt to the punitive process window of photolithography process. But reducing the thickness of photo-resist will reduce the ability of anti-erosion and run out of the photo-resist before contact completely forming. In order to improve the said situation, the invention provides a kind of hard mask process for polycrystalline silicon which is to transfer the pattern of photo-resist to polycrystalline silicon layer by initial etching; then, employing the polycrystalline silicon layer with better anti-erosion ability as the mask for followed etching so as to form the contact of reduced size. Because the hard mask processing is lack of carbon, it will reduce the etching speed and the sidewall of contact will not be smooth. So, the invention provides an improved process with hard mask which is to implant carbon ion in polycrystalline silicon layer providing carbon for enhancing the etching process of contacts.