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New Method for Eliminating CT Residue to Help TS Open Ability

IP.com Disclosure Number: IPCOM000249917D
Publication Date: 2017-May-01
Document File: 3 page(s) / 166K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to treat the Poly Cut (CT) top area surface with Oxygen plasma after Silicon Nitride (SiN) chemical mechanical planarization (CMP) as a means of avoiding SiN residue on the CT area covering interlayer dielectric (ILD).

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Title New Method for Eliminating CT Residue to Help TS Open Ability Abstract Disclosed is a method to treat the Poly Cut (CT) top area surface with Oxygen plasma after Silicon Nitride (SiN) chemical mechanical planarization (CMP) as a means of avoiding SiN residue on the CT area covering interlayer dielectric (ILD). Problem The problem addressed herein is that Trench Silicide (TS) is blocked for 7nm and beyond. Silicon Nitride (SiN) residue found from the Poly Cut (CT) area covering interlayer dielectric (ILD) after CT and even after SiN chemical mechanical planarization (CMP) blocks TS open. A process is needed to avoid SiN residue on the CT area covering ILD. Figure 1: Process on record (POR)

Figure 2: CT residue for downstream problem in TS Impact at TS (e.g., TEG04) - Systematic unetched TS. Thin nitride residue blocks self- aligned contact (SAC) oxide reactive ion etch (RIE).

Figure 3: Prior Art_7nm SiN CMP process flow

Solution/Novel Contribution The novel solution is to treat the CT top area surface with Oxygen plasma after SiN CMP. Method/Process To help the TS RIE open, the process follows:

1. After SAC SiN CMP, add Oxygen Plasma treatment at CT Covering the ILD area 2. Any tiny SiN residue on CT covering the ILD area converts to Silicon oxide 3. Any SiN residue at CT cut area delaminates

Figure 4: New SAC process flow including Oxygen plasma treatment

Reference: J Han, X Shi, C Wu, D Koli, HJ Kim, ECS Journal of Solid State Science and Technology 6 (4), P101-P104....