FinFET Fin-End Separation Structure for Wider Process Window
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Solution Overview
Problem
As semiconductor devices shrink to achieve higher integration density and performance, they face challenges such as reduced process windows, lowered yield, and poor performance due to the difficulties in fabricating fin field effect transistors (FinFETs) with increasingly smaller critical dimensions.
Innovation Solution
The semiconductor device incorporates a fin with a separation structure, a spacer, and a residue of dummy gate material forming a triangle shape between the spacer and the fin end, which increases the distance between the epitaxial source/drain regions and the separation structure, reducing the risk of damage during processing and enhancing the process window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the critical dimensions are reduced to increase device density, then the integration density is improved, but the process window is reduced and manufacturing precision deteriorates
Solution Approach 1:
The dummy gate structure is formed before the separation structure to pre-establish a protective framework. The dummy gate is intentionally left as residue between the separation structure and fin end, creating a buffer zone before source/drain region formation, which prevents direct contact and potential damage during subsequent processing steps.
Solution Approach 2:
The residue of dummy gate material acts as an intermediary element between the separation structure and the fin end. This intermediate material layer physically separates the epitaxial source/drain regions from the separation structure, preventing direct interaction that could cause damage while maintaining the required spatial relationships.
2Quantity of substance
If the critical dimensions are reduced to increase device density, then the integration density is improved, but the yield is lowered
Solution Approach 1:
The residue of dummy gate material serves as a cushioning protective layer formed beforehand between the separation structure and fin end. This pre-formed buffer zone protects the epitaxial source/drain regions from potential damage during separation structure formation, thereby improving manufacturing yield despite reduced critical dimensions.
3Manufacturing precision
If the distance between epitaxial source/drain regions and separation structure is increased, then the process window is improved, but the device area increases
Solution Approach 1:
The dummy gate structure serves multiple functions: it defines the fin geometry during fabrication, provides a template for spacer formation, and its residue automatically creates the protective buffer zone between separation structure and fin end. This self-service approach establishes the protective distance without requiring additional dedicated space or structures.
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 configuration increases the process window, improves yield, and enhances the performance of semiconductor devices by preventing damage to the epitaxial source/drain regions during the formation of the separation structure.
Implementation Method 1
the residue of the dummy gate material separates the first epitaxial source/drain region from the separation structure
Data Source
AI summary
A semiconductor device includes a fin extending from a substrate and including a first fin end, a separation structure separating the first fin end from an adjacent fin end of another fin, a dummy gate spacer along sidewalls of the separation structure and the fin, a first epitaxial source/drain region in the fin and adjacent the separation structure, and a residue of a dummy gate material in a corner region between the dummy gate spacer and the first fin end. The first fin end protrudes from the dummy gate spacer into the separation structure. The residue of the dummy gate material separates the first epitaxial source/drain region from the separation structure and is triangle shaped.