Method for improving CMP process window of deep slot DRAM tungsten metal bit line

Abstract

A method for improving CMP process window of tungsten metal bit line in deep trench DRAM applies new manner as removing off polysilicon layer simultaneously by utilizing hollow etching operation of packing material at MO bit line contact window.

Description

technical field [0001] The present invention relates to a method for fabricating metal interconnects, in particular to improving the chemical mechanical polishing (CMP) process window of tungsten metal bit lines in deep trench dynamic random access memory (Dynamic Random Access Memory, DRAM) method. Background technique [0002] In the interconnection process of deep trench DRAM, the formation process of the bit line metal is as follows: Figure 1A-1D As shown, after the formation of the word line and the contact window, the contact window is filled with photoresist, the recess is etched, and the plug of photoresist is formed to protect the bottom of the contact window from being affected during the subsequent formation of the bit line. The photoresist recess (ARC Recess) etching of the conventional (M0) bit line contact window only considers the shape of the pattern, so the polysilicon layer as the etching barrier layer of the contact window remains, such as Figure 1A sho...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the (M0) bit line formation stage of deep trench DRAM in the prior art, because polysilicon residue causes tungsten metal to grind unevenly, polysilicon residue affects the problem of tungsten metal process window performance

Images