Inter-Layer Dielectric and CESL Structure for Source/Drain Adhesion

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Solution Overview

Problem

Existing semiconductor manufacturing processes face challenges in forming inter-layer dielectrics and etch stop layers that effectively adhere to underlying layers while preventing oxidation and maintaining high adhesion and electrical isolation performance, particularly when using low reactive sticking coefficient deposition methods like FCVD.

Innovation Solution

A combination of nitridation treatment for the contact etch stop layer (CESL) and oxide curing process for the inter-layer dielectric (ILD) is employed to increase nitrogen concentration and reduce impurity concentration, enhancing adhesion and barrier properties to protect underlying layers from oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If FCVD deposition method is used to form inter-layer dielectric, then deposition efficiency is improved, but adhesion performance deteriorates due to low reactive sticking coefficient

Engineering Contradiction:

Improvedeposition efficiencyVSAvoidadhesion performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A contact etch stop layer (CESL) is formed prior to the inter-layer dielectric (ILD) deposition. This preliminary layer serves as an adhesion promoter that compensates for the low adhesion performance of FCVD-deposited ILD, allowing the use of FCVD method while maintaining reliable adhesion.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The CESL acts as an intermediary layer between the underlying structure and the ILD. It mediates the adhesion interface, providing a surface that enhances bonding between the ILD and underlying layers, thus resolving the adhesion problem associated with FCVD deposition.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional ILD formation process is used, then manufacturing simplicity is maintained, but oxidation protection and contamination barrier performance are insufficient

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidoxidation and contamination

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The structure combines CESL and ILD layers with different material properties. The CESL provides oxidation protection and contamination barrier functions, while the ILD provides dielectric functionality. This composite structure enhances protection against harmful factors while maintaining manufacturing simplicity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The CESL is strategically positioned at the interface where oxidation and contamination protection is most critical. This localized approach provides enhanced protection at the vulnerable interface without complicating the overall manufacturing process.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If etch stop layer is formed to prevent oxidation, then barrier performance is improved, but adhesion to underlying layers may deteriorate

Engineering Contradiction:

Improveoxidation protectionVSAvoidadhesion to underlying layers

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The composition and properties of the CESL are carefully controlled to achieve optimal balance between oxidation barrier performance and adhesion. By adjusting material parameters, the CESL provides effective oxidation protection while maintaining good adhesion to underlying layers.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed method improves the adhesion and barrier properties of the ILD, reducing oxidation and contamination diffusion, thereby enhancing the performance and reliability of semiconductor devices.

Implementation Method 1

performing a nitridation treatment process on the contact etch stop layer, the nitridation treatment process increasing the nitrogen concentration of the contact etch stop layer

Methodology Applied

Scientific EffectNitrogen diffusion: Diffusion

Implementation Method 2

performing an oxide curing process on the inter-layer dielectric, the oxide curing process decreasing the impurity concentration of the inter-layer dielectric

Methodology Applied

Scientific EffectThermal treatment: Heat Treatment

Data Source

PatentUS12453118B2Inter-layer dielectrics and etch stop layers for transistor source/drain regions

Publication Date: 2025.10.21 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

In an embodiment, a device includes: a gate structure over a substrate; a gate spacer adjacent the gate structure; a source/drain region adjacent the gate spacer; a first inter-layer dielectric (ILD) on the source/drain region, the first ILD having a first concentration of an impurity; and a second ILD on the first ILD, the second ILD having a second concentration of the impurity, the second concentration being less than the first concentration, top surfaces of the second ILD, the gate spacer, and the gate structure being coplanar; and a source/drain contact extending through the second ILD and the first ILD, the source/drain contact coupled to the source/drain region.