FinFET Replacement Gate Structure for Adjustable Fin Height
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Solution Overview
Problem
The existing replacement gate technique for forming FinFET devices is not readily transferable for changes in fin height, leading to increased time and expense in product design modifications and susceptibility to fin damage during the patterning process.
Innovation Solution
A method involving forming a fin in a semiconducting substrate, creating a sacrificial gate structure, and then removing it to define a gate cavity, allowing for the formation of a replacement gate structure, which includes forming trenches, local isolation regions, etch stop layers, and specific etching processes to pattern the gate structure, thereby enabling flexible fin height adjustments and reducing fin damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the existing replacement gate technique is used for forming FinFET devices, then the gate structure can be formed, but the technique is not readily transferable for changes in fin height, leading to increased time and expense in product design modifications
Solution Approach 1:
The gate formation process is divided into separate stages: first forming a sacrificial gate structure, then removing it to create a gate cavity, and finally forming the replacement gate structure. This segmentation allows the fin height to be determined independently of the gate patterning process, enabling flexible fin height adjustments without requiring requalification of the entire gate patterning process.
Solution Approach 2:
The sacrificial gate structure is formed preliminarily to define the gate cavity boundaries and protect the fin structures during subsequent processing. This preliminary structure enables fin height adjustments to be made before the final gate formation, allowing design modifications without affecting the gate patterning requalification requirements.
2Reliability
If the existing replacement gate technique is used, then the gate structure can be formed, but fin damage occurs during the patterning process
Solution Approach 1:
The sacrificial gate structure serves as an intermediary element that protects the fin structures during processing. It provides a physical barrier and defines the gate cavity boundaries, preventing direct contact between patterning tools and the fin structures, thereby reducing fin damage while still enabling the formation of the final gate structure.
3Ease of manufacture
If traditional gate patterning processes are used, then the process is well-established, but any changes in fin height require extensive requalification
Solution Approach 1:
By separating the fin formation process from the gate patterning process through the use of a sacrificial gate structure, the patent enables fin height modifications to be made independently. The gate cavity is defined by the sacrificial structure rather than by the final gate patterning, allowing fin height changes without requiring requalification of the gate patterning process while maintaining compatibility with established gate formation techniques.
Data Source
AI summary
One illustrative method disclosed herein includes forming a sacrificial gate structure above a fin, wherein the sacrificial gate structure is comprised of a sacrificial gate insulation layer, a layer of insulating material, a sacrificial gate electrode layer and a gate cap layer, forming a sidewall spacer adjacent opposite sides of the sacrificial gate structure, removing the sacrificial gate structure to thereby define a gate cavity that exposes a portion of the fin, and forming a replacement gate structure in the gate cavity. One illustrative device disclosed herein includes a plurality of fin structures that are separated by a trench formed in a substrate, a local isolation material positioned within the trench, a gate structure positioned around portions of the fin structures and above the local isolation material and an etch stop layer positioned between the gate structure and the local isolation material within the trench.