Browse Prior Art Database

A Method to Protect the Channel during FIN Processing while Minimizing the BOX Gouging

IP.com Disclosure Number: IPCOM000246386D
Publication Date: 2016-Jun-02
Document File: 5 page(s) / 93K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that preserves the FIN critical dimension (CD)/profile while minimizing buried oxide (BOX) gouging during FIN processing.

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A Method to Protect the Channel during FIN Processing while Minimizing the BOX Gouging

The problem addressed in this disclosure is Dfin Loss in the Fin module.

Silicon Germanium (SiGe) fin erosion occurs even for 25% SiGe. Higher Ge levels cause more serious erosion problems. For example, organic planarization layer stripping (OPL) by a hot sulfuric acid/hydrogen peroxide mixture (SPM) is not compatible with high SiGe, Ge, and III-V. In addition, a different amount of SiGe and Si FIN loss occurs during nitride hard mask removal. Si fin also undergoes Dfin erosion, highlighting native oxide formation and removal issues. Si and SiGe fins erode to different extents causing large differences in the negative (N) and positive (P) Fin critical dimension (CD) deltas.

Figure 1: Example problem: SOI/SiGe25 (thermal mixing): ~5nm SiGe fin CD loss in the fin module

To keep comparable CDs Si and SiGe fins (and III-V) and achieve good CD control with very little variability in Fin CD during processing is important for circuit performance.

A method is needed to protect SiGe and III-V Fin during Fin fabrication and achieve target CD, including Litho patterning and OPL strip as well as hardmask (HM) removal. Fin Cut (FC) and (Fin preserve) RX reworks are sometimes needed to adjust the CDs of fin preserve and fin cut regions. CD loss occurs during these rework process as well. In addition, a method is needed to minimize any buried oxide (BOX) gouging due to the protection layer r...