Etch Selectivity Tuning for Dummy Fin Epitaxy Window Enlargement
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Solution Overview
Problem
As feature size decreases in semiconductor devices, epitaxial growth processes face challenges due to limited epitaxial region sizes, leading to undesirable outcomes in yield and performance.
Innovation Solution
The modification of etching processes and careful selection of materials to control etch selectivity, allowing for the enlargement of epitaxial regions through the formation of recesses in dummy fins, which enables improved epitaxial growth by increasing the epitaxy process window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature size is decreased to improve device density, then device integration is improved, but epitaxial growth process capability deteriorates due to limited epitaxial region size
Solution Approach 1:
The dummy fin structure is segmented into multiple regions with different etch selectivities. The first portion has a first etch selectivity relative to the spacer structure, while the second portion has a second etch selectivity that is different from the first. This segmentation allows selective removal of portions to create enlarged epitaxial regions while maintaining the overall dummy fin structure for device isolation.
Solution Approach 2:
Different portions of the dummy fin are assigned different local properties through the use of materials with different etch selectivities. The first portion uses a material with a first etch selectivity to the spacer structure, while the second portion uses a material with a second etch selectivity. This local differentiation enables precise control over which regions are removed during epitaxial growth preparation.
2Manufacturing precision
If etch selectivity is increased to improve pattern definition, then manufacturing precision is improved, but epitaxial region enlargement capability deteriorates
Solution Approach 1:
The etch selectivity parameter is changed across different portions of the dummy fin structure. The first portion has a first etch selectivity relative to the spacer structure, while the second portion has a second etch selectivity that is less than the first etch selectivity. This parameter variation allows the etching process to selectively remove material at different rates, enabling both precise pattern definition and epitaxial region enlargement.
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 enhances semiconductor device yield and performance by providing a larger epitaxy process window, reducing defects, and improving the formation of epitaxial material.
Implementation Method 1
modification of etching processes and careful selection of materials used to fabricate the semiconductor device, the present disclosure provides etch selectivity control to enlarge epitaxial regions
Implementation Method 2
epitaxial growth processes used in the fabrication of semiconductor devices
Data Source
AI summary
A semiconductor device and method for fabricating a semiconductor device includes etch selectivity tuning to enlarge epitaxy process windows. Through modification of etching processes and careful selection of materials, improvements in semiconductor device yield and performance can be delivered. Etch selectivity is controlled by using dilute gas, using assistive etch chemicals, controlling a magnitude of bias power used in the etching process, and controlling an amount of passivation gas used in the etching process, among other approaches. A recess is formed in a dummy fin in a region of the semiconductor where epitaxial growth occurs to further enlarge the epitaxy process window.