FinFET Work Function Layer Adhesion Against Etchant Penetration
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Solution Overview
Problem
Existing FinFET technologies face challenges in accurately controlling threshold voltages due to etchant penetration through the interface between the hardmask and patternable layers, leading to undesired loss of work function layers during etching processes.
Innovation Solution
An adhesion layer with organic acid functional groups is formed between the hardmask and patternable layers, enhancing their bonding and preventing etchant penetration, allowing for precise formation of different work function layers without loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hardmask layer and patternable layer are used in the FinFET fabrication process, then the manufacturing precision of work function layers can be improved, but etchant penetration through the interface between layers causes loss of work function layers
Solution Approach 1:
An adhesion layer is introduced as an intermediary between the hardmask layer and the patternable layer. This adhesion layer has enhanced bonding characteristics that prevent etchant penetration through the layer interface, thereby protecting the work function layer from loss while maintaining the manufacturing precision benefits of the multi-layer structure.
Solution Approach 2:
The patent employs a composite layer structure consisting of the hardmask layer, adhesion layer, and patternable layer. Each layer is designed with specific material properties that work together to achieve both precise threshold voltage control and protection against etchant penetration, resolving the contradiction between manufacturing precision and substance loss.
2Ease of manufacture
If the interface between hardmask and patternable layers is used, then the ease of manufacture is improved, but the reliability of threshold voltage control deteriorates due to etchant penetration
Solution Approach 1:
The adhesion layer serves as a mediator that maintains the simplicity of the fabrication process while simultaneously improving threshold voltage control reliability by blocking etchant penetration pathways that would otherwise compromise the work function layer integrity.
3Device complexity
If conventional layer structures are used without adhesion enhancement, then the device complexity is reduced, but the manufacturing precision of work function layers deteriorates due to etchant loss
Solution Approach 1:
The adhesion layer is strategically introduced to improve manufacturing precision of work function layers by preventing etchant penetration, while minimizing the increase in device complexity through a straightforward integration into the existing layer structure.
Solution Approach 2:
The enhanced layer structure uses composite materials with specific bonding characteristics that provide superior protection against etchant penetration, achieving higher manufacturing precision without proportionally increasing device complexity.
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
This solution ensures accurate control of threshold voltages for FinFETs by preventing etchant penetration and maintaining the integrity of work function layers, thereby improving the reliability of FinFET devices.
Implementation Method 1
The adhesion layer includes an organic acid that can concurrently bond metal atoms of the hardmask layer and phenol groups of the patternable layer
Data Source
AI summary
A method for manufacturing a semiconductor device includes forming one or more work function layers over a semiconductor structure. The method includes forming a hardmask layer over the one or more work function layers. The method includes forming an adhesion layer over the hardmask layer. The method includes removing a first portion of a patternable layer that is disposed over the hardmask layer. The adhesion layer comprises an organic acid that concurrently bonds metal atoms of the hardmask layer and phenol groups of the patternable layer, thereby preventing an etchant from penetrating into a second portion of the patternable layer that still remains over the hardmask layer.