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A Novel Method to Remove Non-metallic Hardmask for RMG WFM Patterning Process

IP.com Disclosure Number: IPCOM000240429D
Publication Date: 2015-Jan-29
Document File: 2 page(s) / 50K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to remove non-metallic hardmask for the Replacement Metal Gate (RMG) work function metal (WFM) patterning process. The non-metallic hardmask comprises Low-Temperature Silicon Oxide (LTO), Silicon-Based Anti-Reflective Coating (SiARC), and Silicon Oxynitride (SiON).

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A Novel Method to Remove Non-metallic Hardmask for RMG WFM Patterning Process

A metallic hardmask (i.e. Titanium Anti-Reflective Coating (TiARC)) introduces metal contamination to downstream lithography and Reactive Ion Etching (RIE) tools.

The novel contribution is a non-metallic hardmask comprising Low-Temperature Silicon Oxide (LTO), Silicon-Based Anti-Reflective Coating (SiARC), and Silicon Oxynitride (SiON). This non-metallic hardmask is industrial friendly.

Non-metallic hardmask removal without damaging high-k is very challenging during Replacement Metal Gate (RMG) work function patterning. Chemical Oxide Removal (COR) can remove non-metallic hardmask without damaging high-k in Polysilicon Control (PC) trenches due to high selectivity to high-k and intrinsic etch loading effect. Dilute Hydrofluoric Acid (dHF) is used to remove any RIE residue that is difficult to remove by COR to improve product defects. Work function metal (WFM) wets also help remove any residue from COR to improve device yield.

Figure 1: Process Steps 1-3

Figure 2: Process Steps 4-6

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