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Method and structure of forming robust gate contact

IP.com Disclosure Number: IPCOM000235796D
Publication Date: 2014-Mar-25

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method and structure to introduce electrical isolation structures in the voids inside self-aligned contact (SAC) cap in order to prevent the formation of an electrical short channel between CA (i.e. source, drain contacts) and CB.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 70% of the total text.

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Title

Method and structure of forming robust gate contact

Abstract

Disclosed is a method and structure to introduce electrical isolation structures in the voids inside self-aligned contact (SAC) cap in order to prevent the formation of an electrical short channel between CA (i.e. source, drain contacts) and CB.

Problem

Currently, the self-aligned contact (SAC) cap has embedded pinch-off voids. If the void is filled by the Tungsten (W) deposition, then an electrical short channel is formed between CA (i.e. source, drain contacts) and CB (i.e. gate contact).

Figure 1: Example of the problem

Solution/Novel Contribution

The novel solution introduces electrical isolation structures in the voids inside self- aligned contact (SAC) cap.


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Figure 2: Unique invention structures

Method/Process

Figure 3: Step 1: Post gate stack formation, which includes high-k deposition, work function metal (WFM) layer deposition and recess, Tungsten (W) deposition, and Chemical- Mechanical Planarization (CMP)


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Figure 4: Step 2: W recess

Figure 5: Step 3: Silicon Nitride (SiN) cap deposition and CMP


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Figure 6: Step 4: Additional oxide Inter-Layer Dielectric (ILD) formation

Example Embodiments

Embodiment #1

Figures 7-13 illustrate the steps for Embodiment #1.

Figure 7: Step 1: Gate contact Etch


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Figure 8: Step 2: Thin SiN deposition

Figure 9: Step 3: Source/drain Contact etch


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Figure 10: Step 4: Optical Dispersive Layer (ODL)...