Susceptor Assembly Vacuum Plenum Prevents Backside Deposition
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Solution Overview
Problem
Current spatial atomic layer deposition processes face challenges with backside deposition on substrates in batch processing chambers, where deposition gases can contact the back of the substrate, leading to issues such as up to 30 mm of deposition around the outer edge of the wafer, necessitating a solution to prevent this unwanted deposition.
Innovation Solution
The implementation of a susceptor assembly with a support post that includes a vacuum plenum and purge gas lines, along with radial purge and vacuum feed channels, and a purge ring with compression gaps to enhance gas distribution and pressure uniformity, effectively preventing backside deposition by ensuring uniform gas flow and pressure around the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multi-wafer susceptor arrangement is used in batch processing chambers, then productivity is improved by processing multiple substrates simultaneously, but backside deposition occurs on the substrates due to deposition gases contacting the back of the substrate
Solution Approach 1:
The harmful deposition gas is extracted from the backside region by introducing a dedicated vacuum plenum system beneath the susceptor. This separate vacuum pathway removes deposition gases before they can accumulate and contact the substrate backside, while maintaining the multi-wafer batch processing configuration.
Solution Approach 2:
A purge gas system is introduced as an intermediary between the deposition gas and the substrate backside. The purge gas flows across the backside surface to prevent deposition gas from contacting the substrate, effectively mediating the interaction and preventing harmful deposition while preserving batch processing productivity.
2Ease of manufacture
If deposition gases are introduced into the chamber, then the deposition process is enabled, but backside deposition occurs when gases contact the substrate back
Solution Approach 1:
The gas flow paths are segmented into separate zones: a deposition gas path for the frontside processing and a vacuum/purge path for the backside region. This segmentation allows independent control of gas flow in each zone, enabling effective deposition on the frontside while preventing backside deposition, thus improving manufacturing precision.
Solution Approach 2:
Different gas flow conditions are applied to different regions of the substrate. The frontside receives deposition gas for film formation, while the backside receives vacuum pumping and/or purge gas flow to prevent deposition. This localized differentiation of gas quality and flow characteristics achieves both effective deposition and prevention of backside deposition.
3Device complexity
If a simple susceptor design is used, then device complexity is reduced, but gas distribution uniformity and pressure control are insufficient to prevent backside deposition
Solution Approach 1:
The susceptor is designed with multi-functionality, integrating both frontside deposition support and backside protection capabilities into a single component. The susceptor incorporates vacuum plenum chambers, purge gas channels, and support posts that perform multiple functions: structural support, gas distribution, and vacuum pumping. This universal design achieves precise gas distribution and pressure control without requiring separate complex systems.
Solution Approach 2:
The vacuum plenum chambers and purge gas channels are nested within the susceptor structure itself. The support posts contain internal vacuum channels, and the susceptor body incorporates cavities and passages for gas flow. This nested configuration integrates multiple functions into a compact design, achieving uniform gas distribution and pressure control while maintaining relatively simple overall device complexity.
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 significantly reduces backside deposition by ensuring uniform gas distribution and pressure around the substrate, maintaining the integrity of the deposition process and preventing unwanted film formation on the substrate's backside.
Implementation Method 1
a support post vacuum plenum in fluid communication with a susceptor vacuum plenum in the body of the susceptor
Implementation Method 2
a purge gas line extending through the support post to a purge gas plenum in the body of the susceptor
Data Source
AI summary
Susceptor assemblies comprising a susceptor with a support post are described. The susceptor has a body with a top surface and a bottom surface. The top surface has a plurality of recesses therein. The support post is connected to the bottom surface of the susceptor to rotate the susceptor assembly. The support post includes support post vacuum plenum in fluid communication with a susceptor vacuum plenum in the body of the susceptor. The support post also includes a purge gas line extending through the support post to a purge gas plenum in the body of the susceptor.