Slanted Isolation Region Structure to Prevent Gate Residue Defects

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Solution Overview

Problem

The scaling down of semiconductor integrated circuits (ICs) has increased processing complexity, leading to challenges in manufacturing and reducing defects in gate electrode layers due to residue formation during the fabrication of nanostructure transistors.

Innovation Solution

The implementation of a semiconductor device structure with a slanted top surface in isolation regions, which prevents residue accumulation in sacrificial gate electrode layers, thereby reducing defects and electrical shorts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional planar isolation regions are used in semiconductor fabrication, then the fabrication process is simpler, but residue accumulates in sacrificial gate electrode layers causing defects and electrical shorts

Engineering Contradiction:

Improvegate electrode layer qualityVSAvoidisolation region structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by transitioning from a planar (symmetric) isolation region top surface to a slanted (asymmetric) top surface. This slanted configuration prevents residue accumulation by eliminating flat surfaces where residue can pool, thereby improving gate electrode layer quality without significantly increasing overall device complexity

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent implements curvature by creating a slanted top surface on the isolation region rather than a flat planar surface. This curved/angled surface geometry facilitates residue removal during fabrication processes, preventing defects in the gate electrode layer while maintaining structural integrity

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Productivity

If geometry size is scaled down to increase functional density, then production efficiency increases and costs decrease, but processing complexity and defect rates increase

Engineering Contradiction:

Improveproduction efficiencyVSAvoidprocessing precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-forming the slanted isolation region top surface before depositing the sacrificial gate electrode layer. This preliminary structural preparation prevents residue accumulation issues from arising in the first place, maintaining manufacturing precision even as geometry scales down and functional density increases

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250324669A1Semiconductor device structure and methods of forming the same

Publication Date: 2025.10.16 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Embodiments of the present disclosure provide semiconductor device structures and methods of forming the same. The structure includes first and second source/drain regions disposed over a substrate and an isolation region disposed between the first and second source/drain regions. The isolation region includes a first top surface having a slanted portion and a flat portion, and a portion of the isolation region located between the slanted portion of the first top surface and a plane defined by the flat portion of the first top surface has a width and a height. The width is greater than the height. The structure further includes a plurality of semiconductor layers disposed adjacent the first and second source/drain regions, a gate electrode layer surrounding a portion of each of the plurality of semiconductor layers, and a spacer disposed between the gate electrode layer and the first source/drain region.