Gas Flow Ring Channels for Backside Deposition Control
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Solution Overview
Problem
Existing process chambers face challenges with backside deposition on substrate supports due to process gases entering the volume below the substrate, leading to increased cleaning frequency and reduced process uniformity. Additionally, increasing purge gas flowrates to mitigate this issue increases costs and downtime.
Innovation Solution
The implementation of a gas flow ring around the substrate support in the process chamber, featuring a ring-shaped body with overlapping portions that form a gas flow channel. This design ensures that purge gas flows around the substrate support, reducing the entry of precursor gases into the lower chamber and minimizing backside deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the flowrate of purge gas is increased to prevent process gases from entering the volume below the substrate support, then backside deposition on the substrate support is reduced, but costs increase and chamber cleaning frequency increases
Solution Approach 1:
The gas flow ring is divided into multiple segments with overlapping portions that create distinct gas flow channels. This segmentation allows controlled distribution of purge gas around the substrate support, improving coverage and preventing process gases from entering the lower volume more effectively than a single continuous flow, thereby reducing backside deposition while optimizing purge gas usage
Solution Approach 2:
The overlapping portions of the gas flow ring create a three-dimensional gas flow structure with channels that extend vertically from the bottom to top surfaces. This dimensional approach allows purge gas to flow in multiple directions and paths, enhancing the prevention of process gas intrusion into the lower volume while reducing the total purge gas flowrate required
2Object-affected harmful factors
If the flowrate of purge gas is increased to prevent process gases from entering the volume below the substrate support, then backside deposition on the substrate support is reduced, but downtime for cleaning the chamber increases
Solution Approach 1:
The segmented gas flow ring structure with multiple overlapping portions creates numerous small gas flow channels that provide comprehensive coverage around the substrate support. This segmentation prevents process gases from finding pathways into the lower volume, significantly reducing backside deposition and thereby decreasing the frequency and downtime of chamber cleaning operations
Solution Approach 2:
The gas flow ring acts as an intermediary structure between the purge gas source and the substrate support. It distributes and directs purge gas flow in a controlled manner through its overlapping portions and gas flow channels, effectively blocking process gases from entering the lower volume and preventing backside deposition without requiring excessive purge gas flowrates
3Object-affected harmful factors
If the flowrate of purge gas is increased to prevent process gases from entering the volume below the substrate support, then process gas intrusion is reduced, but costs increase
Solution Approach 1:
The gas flow ring is segmented into multiple overlapping portions that create numerous gas flow channels. This segmentation allows purge gas to be distributed efficiently around the substrate support, forming effective barriers against process gas intrusion into the lower volume while minimizing the total purge gas flowrate required compared to conventional single-flow designs
Solution Approach 2:
The overlapping portions of the gas flow ring create localized gas flow channels with specific flow characteristics at different positions around the substrate support. This local quality optimization ensures that purge gas is delivered precisely where needed to block process gas intrusion, improving effectiveness while reducing overall purge gas consumption
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 gas flow ring enhances the balance and uniformity of purge gas flow around the substrate, reducing unintended depositions and the need for frequent chamber cleaning. This results in cost savings from reduced purge gas usage and increased process efficiency with improved uniformity.
Implementation Method 1
a gas flow ring disposed around an outer edge of the substrate support, the gas flow ring comprising: a ring-shaped body; a top surface; a bottom surface; a first overlapping portion extending from a first inner sidewall of the ring-shaped body; and a second overlapping portion extending from a second inner sidewall of the ring-shaped body, wherein the first overlapping portion is spaced apart from and overlies the second overlapping portion to form a gas flow channel that extends from the bottom surface to the top surface of the gas flow ring
Data Source
AI summary
A process chamber including: a chamber body enclosing an interior volume; a substrate support disposed in the interior volume that includes a lower interior volume below the substrate support and an upper interior volume above the substrate support; a first purge gas line configured to provide a first flow of purge gas to the lower interior volume; and a gas flow ring disposed around an outer edge of the substrate support, the gas flow ring comprising: a ring-shaped body; a top surface; a bottom surface; a first overlapping portion extending from a first inner sidewall of the ring-shaped body; and a second overlapping portion extending from a second inner sidewall of the ring-shaped body. The first overlapping portion is spaced apart from and overlies the second overlapping portion to form a gas flow channel that extends from the bottom surface to the top surface of the gas flow ring.