Overlap Susceptor and Preheat Ring for Chamber Gas Separation
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Solution Overview
Problem
Existing semiconductor processing chambers face challenges in controlling gas flow, leading to gas exchange between process and purge gas flows, which affects deposition uniformity and tool uptime due to dilution and undesirable material deposition.
Innovation Solution
The implementation of an overlapping susceptor and preheat ring design, combined with a vented liner and dynamic pressure balancing, prevents gas exchange between upper and lower chamber volumes by exhausting purge gas directly from the lower portion and regulating pressure differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If purge gas flow is used to prevent process gas diffusion into the lower portion, then gas exchange between process and purge gas is reduced, but gas exchange still occurs which is detrimental to deposition
Solution Approach 1:
The chamber is divided into two separate exhaust paths: one for process gas from the upper chamber volume and one for purge gas from the lower chamber volume. This segmentation prevents mixing of the two gas streams while maintaining their respective functions, thereby eliminating the harmful gas exchange that occurs in conventional single-path exhaust systems.
Solution Approach 2:
A liner structure acts as an intermediary component between the upper and lower chamber volumes. The liner includes a vent that selectively allows purge gas to pass through while blocking process gas, serving as a mediator that separates the two gas flows and prevents detrimental mixing while maintaining pressure balance.
2Productivity
If process gas flows parallel to substrate surface for deposition, then material is deposited onto substrate, but process gas may diffuse into lower portion causing undesirable material deposition
Solution Approach 1:
The harmful effect of process gas diffusion into the lower chamber is eliminated by extracting and separately exhausting process gas through a dedicated exhaust path in the upper chamber. This prevents process gas from reaching the lower chamber components where it would cause undesirable material deposition, while maintaining efficient deposition on the substrate.
3Stress or pressure
If gas exchange occurs between upper and lower chamber volumes, then pressure balance may be maintained, but deposition uniformity deteriorates due to gas dilution
Solution Approach 1:
The exhaust system is segmented into separate paths for upper and lower chamber volumes, allowing independent pressure control. This enables maintenance of pressure balance through separate exhaust flows without the detrimental gas mixing that causes deposition uniformity issues, as each chamber volume can be optimized independently.
Data Source
AI summary
Embodiments disclosed herein generally provide improved control of gas flow in processing chambers. In at least one embodiment, a liner for a processing chamber includes an annular body having a sidewall and a vent formed in the annular body for exhausting gas from inside to outside the annular body. The vent comprises one or more vent holes disposed through the sidewall. The liner further includes an opening in the annular body for substrate loading and unloading.