Dry Strip Removal of Si-Containing Anti-Reflective Coating Photo Resist Stacks

Abstract

Removal of SiARC containing photo resist stacks presents significant challenges to conventional plasma dry strip tools. Due to the high Si content (35-45% Si), the SiARC removal process must typically be done with a combination of dry and wet processes or done entirely in an etcher. As both the Dry-Wet-Dry and the Etcher approach to SiARC stack removal are long and high cost processes, a single chamber, dry-only solution to SiARC stack removal is highly desirable. This paper reports the dry strip process developed at Axcelis Technologies, Inc. to remove the SiARC stack layer by layer which results in a residue free oxide substrate.

Advanced Wet-Etch-Only Process for Complete Tri-Layer Rework

“…Therefore, the industry is trying to find a complete rework that can be executed in just one process, reducing the overall cost by increasing throughput. A complete rework with dry processes has been reported by Mattson et al [6]. However, it has difficulties in the dry etch of SiARC when the silicon content is high.…”

Effects of Plasma and Wet Processes on Si-Rich Anti-Reflective Coating to Address Selective Trilayer Rework for Sub-20nm Technology Nodes

“…In the case of trilayer rework though, the challenge is somewhat more complex since a layer with an uncommon chemical composition compared to standard lithography reworks, the Si-BARC, is introduced. So far, reported rework processes mostly focused on removing the entire stack either by evaluating efficiency of well-known chemistries such as Sulfuric-Peroxide-Mixture (SPM) on trilayers (5) or by developing specific processes with successive steps to sequentially strip off each layer selectively to the underneath material (6).…”