Shared Accumulator for Plasma Gas Pressure Stabilization
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Solution Overview
Problem
The single-line-drop approach in cluster tools, where multiple mass flow controllers (MFCs) share a single regulator, often results in processing performance issues such as etch profile and uniformity problems due to pressure fluctuations, affecting yield.
Innovation Solution
Incorporating a shared accumulator between the MFCs and the shared regulator to absorb pressure spikes and dips, increasing the combined manifold and accumulator volume, thereby reducing MFC cross-talk and stabilizing input pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple MFCs share a single regulator via a shared manifold, then cost and spatial efficiency are improved, but processing performance deteriorates due to pressure fluctuations affecting etch profile and uniformity
Solution Approach 1:
The system segments the gas supply path by introducing a shared accumulator between the shared regulator and the multiple MFCs. This segmentation isolates the MFCs from direct pressure fluctuations originating at the regulator, allowing the regulator to serve multiple MFCs without compromising individual MFC performance. The accumulator acts as a buffer zone that decouples the regulatory function from the distribution function.
Solution Approach 2:
The shared accumulator serves as an intermediary component between the shared regulator and the multiple MFCs. It mediates the pressure transmission by absorbing spikes and dips, preventing direct pressure variations from the regulator from affecting the MFCs. This intermediary buffer enables cost-effective shared regulation while maintaining the precision required for accurate mass flow control.
2Area of stationary object
If multiple MFCs share a single regulator, then spatial efficiency is improved by reducing regulators near chambers, but pressure stability deteriorates causing MFC cross-talk
Solution Approach 1:
The solution relocates the regulator from the traditional location near the chamber to a remote location, utilizing another dimension of space. The shared accumulator is positioned near the chamber to provide local pressure buffering, while the regulator operates remotely. This spatial reconfiguration reduces clutter near the chamber while maintaining pressure stability through the accumulator's buffering action.
Solution Approach 2:
The shared accumulator acts as an intermediary that bridges the remote regulator and the nearby MFCs. It receives regulated gas from the remote regulator and provides stable pressure to the MFCs locally, eliminating the need for the regulator to be positioned near the chamber while maintaining pressure stability and preventing MFC cross-talk.
3Area of stationary object
If regulator is positioned remotely from MFCs, then spatial efficiency is improved, but pressure control precision deteriorates without accumulation buffer
Solution Approach 1:
The shared accumulator serves as a critical intermediary between the remote regulator and the MFCs. It compensates for the distance by providing local pressure buffering, ensuring that pressure control precision is maintained despite the regulator's remote position. The accumulator's volume is specifically designed to absorb pressure variations that would otherwise propagate from the remote regulator to the MFCs.
Solution Approach 2:
The system segments the pressure control function from the gas distribution function. The remote regulator handles gas distribution to multiple lines, while the shared accumulator near the MFCs handles pressure stabilization. This segmentation allows the regulator to be remotely positioned for space efficiency while the accumulator ensures precise pressure control where needed.
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 solution enhances processing performance by minimizing pressure fluctuations, improving etch profile and uniformity, and maintaining yield, while maintaining spatial efficiency and reducing costs.
Implementation Method 1
Incorporating a shared accumulator between the MFCs and the shared regulator to absorb pressure spikes and dips
Data Source
AI summary
Methods and apparatus for supplying gas in a plasma processing system that employs the single line drop approach wherein a regulator is shared among multiple mass flow controllers. In one or more embodiments, an accumulator is provided and coupled in gaseous communication with a shared manifold to reduce pressure spikes and dips. A filter, which may be replaceable or non-replaceable separate from the accumulator, is integrated with the accumulator in one or more embodiments.