Source/Drain Epitaxy With Metal Mask for Residue Control
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Solution Overview
Problem
As semiconductor devices continue to shrink in feature size, challenges arise in forming reliable source/drain regions during epitaxy processes, including precursor absorption and residue removal, which can lead to defects and reduced integration density.
Innovation Solution
The use of a metal-comprising mask, such as aluminum oxide or hafnium oxide, during source/drain epitaxy processes helps protect structures and inhibit epitaxy growth along crystalline planes, allowing for more effective precursor residue removal and improved processing windows by forming high-energy bonds with precursors, thereby reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional masking materials are used during epitaxy processes, then precursor absorption occurs leading to residue formation, but defect reduction and processing window improvement are needed
Solution Approach 1:
A metal-comprising mask layer (aluminum, aluminum oxide, or aluminum nitride) is introduced as an intermediary material between the precursor and the underlying structures. This mask layer forms high-energy bonds with precursors during epitaxy, preventing precursor absorption into the substrate and facilitating easier residue removal, thereby reducing defects while improving processing windows
Solution Approach 2:
The patent changes the material parameter of the mask from conventional organic or inorganic materials to metal-comprising materials (aluminum, aluminum oxide, aluminum nitride). This parameter change enables the mask to form high-energy bonds with precursors, fundamentally altering the interaction mechanism and enabling both defect reduction and improved residue removal characteristics
2Productivity
If feature size is reduced to increase integration density, then more components can be integrated, but manufacturing precision and reliability of source/drain regions deteriorate
Solution Approach 1:
The metal-comprising mask serves as a protective intermediary during epitaxy processes in scaled devices. By forming high-energy bonds with precursors and preventing unwanted absorption, it enables precise control of source/drain region formation even at reduced feature sizes, maintaining manufacturing precision while supporting higher integration density
Solution Approach 2:
The introduction of metal-comprising mask materials changes the chemical interaction parameters during epitaxy, enabling better control over precursor behavior. This parameter change allows for reliable source/drain region formation in nano-scale devices where conventional materials fail to provide sufficient control
3Productivity
If epitaxy growth is allowed to proceed without inhibition, then source/drain regions form, but growth along crystalline planes causes defects
Solution Approach 1:
The metal-comprising mask acts as a controlled intermediary that modulates epitaxial growth. It allows growth in desired directions while forming high-energy bonds with precursors that inhibit unwanted growth along crystalline planes, thereby maintaining growth efficiency while improving crystalline quality and reducing defects
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 the formation of source/drain regions by reducing defects and improving processing windows, allowing for more efficient and reliable epitaxial growth, especially in nano-FETs and other transistor types.
Implementation Method 1
improve processing windows by forming high-energy bonds with precursors
Implementation Method 2
inhibit epitaxy growth along crystalline planes
Data Source
AI summary
A method includes etching a first recess adjacent a first dummy gate stack and a first fin; etching a second recess adjacent a second dummy gate stack and a second fin; and epitaxially growing a first epitaxy region in the first recess. The method further includes depositing a first metal-comprising mask over the first dummy gate stack, over the second dummy gate stack, over the first epitaxy region in the first recess, and in the second recess; patterning the first metal-comprising mask to expose the first dummy gate stack and the first epitaxy region; epitaxially growing a second epitaxy region in the first recess over the first epitaxy region; and after epitaxially growing the second epitaxy region, removing remaining portions of the first metal-comprising mask.