Purge Ring Geometry for Reduced Substrate Backside Deposition
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Solution Overview
Problem
Deposition process chambers in the semiconductor industry face issues with unwanted backside deposition, substrate peeling, and particle contamination due to gas diffusion during the deposition of thin layers, which existing technologies have not adequately addressed.
Innovation Solution
A purge ring design with a specific annular body structure and gas flow path configuration is introduced, featuring inner and outer portions with notches and sidewalls that enhance edge purge flow speed along the substrate's backside, preventing front-side gases from reaching the substrate's backside.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If process gases are used for deposition, then thin layers of materials can be deposited onto substrates, but unwanted backside deposition and substrate peeling occur due to gas diffusion
Solution Approach 1:
A purge ring is introduced as an intermediary component between the process gas delivery system and the substrate. The purge ring delivers purge gas that acts as a mediator to prevent process gas from reaching the substrate backside, thereby eliminating backside deposition while maintaining the deposition process on the front side
Solution Approach 2:
The harmful process gas is extracted or removed from reaching the substrate backside by the purge ring structure. The purge ring creates a physical barrier and flow pattern that extracts process gas from the region near the substrate backside before it can cause unwanted deposition
2Reliability
If purge gas flow is increased to prevent backside deposition, then substrate peeling is reduced, but edge purge flow speed may be insufficient to prevent particle issues
Solution Approach 1:
The purge ring features locally optimized geometry with specific edge configurations that concentrate and accelerate purge gas flow at the edges. This local quality enhancement ensures high edge purge flow speed that prevents particle issues while maintaining overall substrate stability through controlled purge gas distribution
3Ease of operation
If existing purge ring designs are used, then basic purge function is provided, but edge purge flow speed is insufficient to prevent front-side gases from reaching substrate backside
Solution Approach 1:
The purge ring incorporates three-dimensional geometric features including angled surfaces and elevated edges that create multi-dimensional gas flow paths. This dimensional complexity enhances edge purge flow speed by creating pressure differentials and flow acceleration zones that two-dimensional designs cannot achieve
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
The purge ring effectively prevents unwanted deposition by increasing edge purge flow speed, thereby reducing substrate peeling and particle issues, ensuring a cleaner and more controlled deposition process.
Implementation Method 1
enhance edge purge flow speed along the substrate's backside, preventing front-side gases from reaching the substrate's backside
Data Source
AI summary
Embodiments of a purge ring for use in a process chamber are provided herein. In some embodiments, a purge ring includes: an annular body having an inner portion and an outer portion, wherein the inner portion includes an inner surface of the annular body, the inner surface comprising a first inner sidewall, a second inner sidewall, and a third inner sidewall, wherein the inner portion has an upper inner notch that defines the first inner sidewall and a lower inner notch that defines the second inner sidewall, wherein a third inner sidewall is disposed between the first inner sidewall and the second inner sidewall, and wherein the first inner sidewall and the second inner sidewall are disposed radially outward of the third inner sidewall.