Overlap Susceptor and Preheat Ring for Purge Gas Exhaust Control
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Solution Overview
Problem
Current processing chambers face challenges in controlling gas flow, leading to gas exchange between process and purge gas flows, which can result in poor deposition uniformity and tool downtime due to gas dilution and material deposition on unwanted surfaces.
Innovation Solution
The implementation of an overlapping susceptor and preheat ring design, combined with a vented liner and dynamic pressure balancing system, which prevents gas exchange and allows for direct exhaust of purge gas, thereby maintaining pressure differentials and improving deposition process uniformity.
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 dilution and material deposition on unwanted surfaces still occur
Solution Approach 1:
The chamber is divided into two separate exhaust systems: a first exhaust port for process gas from the upper chamber volume and a second exhaust port for purge gas from the lower chamber volume. This segmentation prevents mixing of process and purge gas streams, eliminating gas dilution while maintaining effective gas flow control.
Solution Approach 2:
A vented liner with vents is introduced as an intermediary component between the susceptor and chamber wall. This liner provides a controlled path for purge gas exhaust while preventing direct contact between process gas and purge gas, thereby preventing material deposition on the chamber wall while maintaining pressure differentials.
2Manufacturing precision
If overlapping susceptor and preheat ring are used, then gas exchange between upper and lower chamber volumes is prevented, but device complexity increases
Solution Approach 1:
The susceptor and preheat ring are designed to radially overlap, merging their functional zones to create a barrier that prevents gas exchange between upper and lower chamber volumes. This combined configuration achieves improved deposition uniformity without requiring separate isolated systems.
Solution Approach 2:
The overlapping configuration extends the barrier function into the radial dimension, creating a three-dimensional gas flow control mechanism that prevents lateral gas exchange while maintaining vertical process gas flow, thereby improving deposition uniformity without complex additional components.
3Measurement precision
If direct exhaust of purge gas is implemented, then pressure differential control is improved, but additional exhaust ports and control systems are required
Solution Approach 1:
The exhaust system is segmented into separate ports for process gas and purge gas, with dedicated exhaust paths that simplify pressure control. This segmentation enables precise pressure differential measurement while avoiding the complexity of mixed gas flow management.
Solution Approach 2:
A pressure balancing valve with differential pressure sensor provides feedback control for the purge gas exhaust port. The sensor monitors pressure differential and adjusts the valve to maintain optimal pressure balance, improving measurement precision while using a relatively simple control mechanism.
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 enhances deposition uniformity and tool uptime by preventing gas dilution and material deposition on surfaces, extending maintenance intervals and improving the precision of gas flow control.
Implementation Method 1
maintaining pressure differentials and improving the precision of gas flow control
Implementation Method 2
an overlapping susceptor and preheat ring design, combined with a vented liner and dynamic pressure balancing system, which prevents gas exchange
Implementation Method 3
a pressure balancing valve configured to fluidly couple the first and second exhaust ports to a vacuum source. The pressure balancing valve is operable to regulate the pressure differential between the upper chamber volume and lower chamber volume
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.