Dual-Thickness Etch-Stop Layers for Source/Drain Contacts

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Solution Overview

Problem

The challenge in semiconductor manufacturing is to improve integration density and electrical connections in semiconductor devices by reducing the overall thickness of the device while maintaining effective conductive feature profiles over gate stacks and source/drain regions.

Innovation Solution

The formation of an etch stop layer within the recesses of contact plugs in semiconductor devices, which aids in subsequent processing steps and reduces the overall thickness of the device, thereby improving electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the overall thickness of the semiconductor device is reduced, then integration density is improved, but maintaining effective conductive feature profiles becomes difficult

Engineering Contradiction:

Improveoverall thicknessVSAvoidconductive feature profile

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

An etch stop layer is introduced as an intermediary component between the conductive feature and the gate stack. This etch stop layer has a thickness of 1-10 nm and provides a controlled etch resistance that enables precise formation of conductive feature profiles during the etching process, even in thinned devices

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the etch resistance parameter by introducing the etch stop layer with specific thickness (1-10 nm) and material properties. This parameter change allows the etching process to self-limit at the desired depth, maintaining conductive feature profile precision while enabling overall device thinning

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the thickness of the device is reduced, then integration density improves, but electrical connection quality may deteriorate

Engineering Contradiction:

Improvedevice thicknessVSAvoidelectrical connection

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The etch stop layer is formed in advance before the conductive feature deposition. This preliminary action establishes a precise stopping point for subsequent etching operations, ensuring that conductive features are formed at the optimal location for electrical connection, even in thinned devices

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12453144B2Semiconductor device comprising first etch stop layer over first conductive feature over source/drain region

Publication Date: 2025.10.21 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device including an etch stop layer and a method of forming is provided. The semiconductor device may include a source/drain region and a gate structure, wherein a first etch stop layer is over a conductive plug to a source/drain region and a second etch stop layer is over the gate structure. The first etch stop layer and the second etch stop layer may have different thicknesses. A dielectric layer may be formed over the first etch stop layer and the second etch stop layer, and contacts may be formed through the dielectric layer and the first and second etch stop layers.