Parylene Coating Pump Switching for Faster Chamber Pump-Down
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Solution Overview
Problem
Current parylene coating systems face challenges with slow pump down times and high costs, making them impractical for wide-scale application due to inefficient use of single oil pumps and other pumping systems that are ineffective at low pressures.
Innovation Solution
Integration of multiple turbo pumps into the pumping system, including a mechanical pump and a turbo pump, with a controller to manage the switching between them based on pressure levels, optimizing the pump down process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single mechanical pump is used for vacuum evacuation, then the system structure is simple, but the pump down time is excessive and the system cannot achieve adequate low pressure
Solution Approach 1:
The pumping system is segmented into two distinct stages: a mechanical pump for rough vacuum evacuation and a turbomolecular pump for high vacuum achievement. This segmentation allows each pump to operate in its optimal pressure range, with the mechanical pump handling the initial evacuation and the turbomolecular pump taking over at lower pressures, thereby reducing total pump down time while maintaining system effectiveness.
Solution Approach 2:
The system dynamically switches between different pumping mechanisms based on pressure conditions. The controller activates the mechanical pump first, then transitions to the turbomolecular pump when the pressure reaches a threshold level. This dynamic adaptation optimizes the pump down process by using the appropriate pump type for each pressure stage, resolving the contradiction between system simplicity and pump down efficiency.
2Ease of manufacture
If a single mechanical pump is used, then the cost is lower, but the pump down time is excessive and low pressure performance is inadequate
Solution Approach 1:
The pumping system is divided into two functional segments: a mechanical pump for initial evacuation and a turbomolecular pump for achieving the low pressures required for efficient parylene deposition. This segmentation enables the system to achieve deposition-ready pressures much faster than a single mechanical pump could, thereby increasing productivity without prohibitively increasing cost.
Solution Approach 2:
The system changes the operational parameters by introducing a second pumping mechanism that operates at different pressure ranges. The turbomolecular pump is specifically designed to operate efficiently at the low pressures needed for deposition, changing the overall pressure achievement capability of the system and thereby increasing deposition rate and productivity.
3Reliability
If a turbomolecular pump is used alone, then the low pressure performance is excellent, but the pump cannot operate effectively at higher pressures during initial evacuation
Solution Approach 1:
The pumping system segments the pressure range into two zones: the mechanical pump handles the higher pressure zone during initial evacuation, while the turbomolecular pump handles the lower pressure zone for deposition. This segmentation allows the turbomolecular pump to operate exclusively in its optimal low-pressure range, maintaining excellent low pressure performance while the mechanical pump provides the necessary high-pressure evacuation capability.
Solution Approach 2:
The mechanical pump acts as an intermediary that prepares the system by evacuating to a preliminary pressure level before the turbomolecular pump is activated. This intermediary action allows the turbomolecular pump to start operating in its optimal pressure range, thereby maintaining its excellent low pressure performance while achieving the necessary pressure range adaptability through the combined system.
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
Reduces pump down time and costs, making parylene coating more accessible to a variety of parts and substrates by efficiently achieving and maintaining target pressures for deposition.
Implementation Method 1
a second pump, wherein a pumping speed of each of the first pump and the second pump is based at least in part on an operating pressure
Data Source
AI summary
A coating system for parylene deposition may include a chamber, a pumping system having a first and a second pump, where a pumping speed of the first and second pumps is based at least in part on an operating pressure; and a controller, the controller configured by machine-readable instructions to control activation of the first pump to initiate a pump down operation of the chamber, determine a cut-in pressure for switching operation from the first to the second pump, monitor an internal pressure of the chamber, switch operation to the second pump based at least in part on determining that the internal pressure of the chamber is at or below the cut-in pressure; and continue, using the second pump, the pump down operation of the deposition chamber until the internal pressure is at or below a target pressure for parylene deposition.