Self-Aligned Epitaxy Layers for FinFET Isolation Precision
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices shrink in size, challenges arise in accurately patterning and aligning structures for FinFET devices, particularly in growing epitaxy layers without electrical shorts and patterning gate electrodes without damaging them, due to decreased spacing between adjacent fins.
Innovation Solution
A self-aligned epitaxy process using a germanium-containing oxide layer and dummy fin structures to isolate epitaxy layers and gate electrodes, eliminating the need for additional alignment and etching processes, thereby simplifying integration and preventing damage to gate electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional alignment and etching processes are used to pattern structures, then manufacturing precision is improved, but device complexity and process integration difficulty increase
Solution Approach 1:
The patent applies preliminary action by forming dummy fin structures before the main epitaxy process. These dummy fins are positioned in advance to define the exact locations where epitaxy layers should grow, eliminating the need for subsequent alignment processes. The dummy fins serve as pre-established guides that automatically determine the positioning of critical structures, thereby improving manufacturing precision while reducing process complexity.
Solution Approach 2:
The dummy fin structures perform multiple functions automatically: they serve as alignment guides for epitaxy growth, act as etch masks for isolating gate electrodes, and define source/drain region boundaries. This self-service capability eliminates the need for separate alignment and etching processes, as the dummy fins inherently provide all necessary patterning functions through the self-aligned nature of the subsequent processing steps.
2Productivity
If spacing between adjacent fins is decreased to increase device density, then productivity is improved, but manufacturing precision deteriorates due to alignment difficulties
Solution Approach 1:
The dummy fin structures enable self-aligned patterning where the position of each fin structure automatically defines the position of its associated epitaxy layer and gate electrode without requiring external alignment. This self-service mechanism eliminates alignment errors that would normally accumulate with decreased spacing, allowing high device density to be achieved while maintaining manufacturing precision through the inherent self-registration of all structures.
3Manufacturing precision
If conventional etching processes are used to isolate gate electrodes, then manufacturing precision is improved, but object-generated harmful factors increase due to etch damage
Solution Approach 1:
The dummy fin structures serve as intermediary elements that enable the isolation of gate electrodes without direct etching of the gate electrode structures themselves. The dummy fins act as sacrificial intermediaries that are etched away to create isolation, or as protective masks that prevent etch damage to the gate electrodes, thereby achieving precise isolation while eliminating the harmful etch damage that would occur with conventional direct etching methods.
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 improves process integration, device performance, and allows for further size scaling by increasing the source/drain landing area and isolating gate electrodes without etch damage, enhancing the margin for device densification.
Implementation Method 1
Self-aligned epitaxy process using a germanium-containing oxide layer
Data Source
AI summary
Semiconductor structures including active fin structures, dummy fin structures, epitaxy layers, a Ge containing oxide layer and methods of manufacture thereof are described. By implementing the Ge containing oxide layer on the surface of the epitaxy layers formed on the source/drain regions of some of the FinFET devices, a self-aligned epitaxy process is enabled. By implementing dummy fin structures and a self-aligned etch, both the epitaxy layers and metal gate structures from adjacent FinFET devices are isolated in a self-aligned manner.