FinFET Isolation Structure with Thick Gap Fill for Yield

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Solution Overview

Problem

The challenge in semiconductor manufacturing lies in forming reliable semiconductor devices at increasingly smaller sizes, as feature sizes decrease, making fabrication processes more difficult and complex.

Innovation Solution

A semiconductor device structure is formed with fin structures and an isolation structure having different thicknesses, where a thick portion of the isolation structure fills the gap between fin structures, preventing damage to stressors during dummy gate stack removal and improving yield by avoiding footing structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If feature sizes are decreased to increase functional density, then production efficiency is improved and costs are lowered, but fabrication process difficulty increases and device reliability becomes harder to ensure

Engineering Contradiction:

Improveproduction efficiencyVSAvoiddevice reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The isolation structure is designed with varying thicknesses - a first thickness in the gap region between fins and a second thickness elsewhere. This local differentiation allows the gap region to be filled more effectively, preventing etchant access to stressors while maintaining appropriate isolation in other regions, thus improving device reliability at scaled dimensions

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The isolation structure is formed before stressor deposition, preliminarily preventing etchant access to the stressor region. This preliminary protective action ensures that subsequent processing steps cannot damage the stressors, maintaining device reliability throughout the fabrication process

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If conventional isolation structures are used with uniform thickness, then manufacturing is simpler, but footing structures form during dummy gate stack removal causing stressor damage

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidfooting structure formation

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The isolation structure implements local quality variation with different thicknesses in different regions. The thicker portion in the gap prevents footing structure formation during dummy gate stack removal, while other regions maintain appropriate isolation thickness, eliminating the manufacturing precision issue without significantly complicating the manufacturing process

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9941386B2Semiconductor device structure with fin structure and method for forming the same

Publication Date: 2018.04.10 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device structure is provided. The semiconductor device structure includes a substrate. The semiconductor device structure includes a first fin structure and a second fin structure over the substrate. There is a gap between the first fin structure and the second fin structure. The semiconductor device structure includes an isolation structure having a thin portion and a thick portion. A first upper portion of the first fin structure and a second upper portion of the second fin structure protrude from the thin portion. The thick portion is partially between the first upper portion and the second upper portion. The semiconductor device structure includes a dummy gate electrode over the thick portion, the first upper portion, and the second upper portion. The semiconductor device structure includes a gate electrode over the first fin structure and the thin portion.