FinFET Hardmask Adhesion Layer for Threshold Voltage Control
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Solution Overview
Problem
Existing FinFET manufacturing processes face issues with etchants penetrating through the interface between the hardmask layer and patternable layer, leading to undesired loss of work function layers and inaccurate threshold voltage control.
Innovation Solution
Incorporating an adhesion layer with organic acid functionality that bonds metal atoms of the hardmask layer and phenol groups of the patternable layer, enhancing the adhesion between the two layers and preventing etchant penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hardmask layer and patternable layer are used in FinFET manufacturing, then patterning and threshold voltage control are enabled, but etchants penetrate through the interface between layers causing loss of work function layers
Solution Approach 1:
An adhesion layer comprising an organic acid is introduced between the hardmask layer and the patternable layer. This intermediary layer prevents etchant penetration through the interface while maintaining strong bonding between the hardmask and patternable layers, thereby protecting the work function layer from loss during etching processes.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers including the hardmask layer, adhesion layer with organic acid, and patternable layer. This composite material system combines the protective properties of the hardmask, the bonding properties of the organic acid-containing adhesion layer, and the patterning capabilities of the patternable layer to achieve both precision and reliability.
2Reliability
If the adhesion between hardmask layer and patternable layer is strengthened, then etchant penetration is prevented, but process complexity increases
Solution Approach 1:
The adhesion layer containing organic acid serves as a mediator that chemically bonds to both the hardmask layer and the patternable layer. This intermediary approach achieves strong interlayer adhesion through chemical bonding mechanisms without requiring complex structural modifications or additional processing steps.
Solution Approach 2:
The patent modifies the chemical composition parameter of the interface between layers by incorporating organic acid functional groups. This parameter change enables strong chemical bonding and etchant resistance without fundamentally altering the overall layer structure or requiring additional complex processing equipment.
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 approach allows for accurate control of threshold voltages by preventing undesired loss of work function layers during etching, ensuring precise FinFET performance.
Implementation Method 1
The adhesion layer comprises an organic acid that concurrently bonds 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.