Movable Shower Head Gas Switching Time Reduction
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Solution Overview
Problem
In plasma chemical vapor deposition processes, the gas switching time is prolonged due to gas retention in the outer peripheral region of the plenum space without gas injection holes, hindering efficient purge processes and potentially contaminating the film formation target with residual gases.
Innovation Solution
A film forming apparatus with a movable shower head that moves between two positions, allowing gas introduction via gas injection holes at one position and a gap at another, enhancing gas flow conductance during the purge process by directing purge gas through a larger gap and slits, rather than just the injection holes, thereby expediting the removal of residual reactants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gas is introduced only through gas injection holes in the shower head, then film formation is achieved, but gas switching time is prolonged due to gas retention in the outer peripheral region of the plenum space
Solution Approach 1:
The gas introduction path is segmented into two separate paths: one through gas injection holes for film formation, and another through a gap between the shower head and chamber wall for rapid purging. This segmentation allows different gas introduction modes for different process stages, resolving the contradiction between maintaining film formation quality and reducing gas switching time.
Solution Approach 2:
The system dynamically switches between two gas introduction configurations: during film formation, gas is introduced only through injection holes; during purging, the shower head is retracted to introduce gas through both injection holes and the peripheral gap. This dynamic adjustment optimizes performance for each process stage, reducing gas switching time while maintaining film formation quality.
2Manufacturing precision
If the shower head is fixed in position, then gas introduction through injection holes is maintained for film formation, but residual gas remains in the outer peripheral region preventing effective purging
Solution Approach 1:
The shower head is made movable along the vertical direction, allowing it to switch between a lowered position (for consistent film formation through injection holes only) and a raised position (for effective purging through the peripheral gap). This dynamic positioning resolves the contradiction between film formation consistency and purge efficiency.
Solution Approach 2:
The solution adds a vertical dimension to the gas introduction system by retracting the shower head upward, creating a new gas introduction path through the peripheral gap between the shower head and chamber wall. This dimensional change enables effective purging without compromising film formation quality during the deposition phase.
3Productivity
If purge gas flows only through gas injection holes, then residual gas removal is limited, but introducing additional flow paths increases device complexity
Solution Approach 1:
The system uses the existing peripheral space between the shower head and chamber wall as a self-service purging path. By simply retracting the shower head, the gap naturally forms and enables rapid purging without requiring additional complex structures, valves, or flow path modifications. This resolves the contradiction between residual gas removal rate and device complexity.
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 significantly shortens the gas switching time and prevents contamination by effectively scavenging residual gases from the shower head and chamber, ensuring rapid and thorough purge processes.
Implementation Method 1
a gas introduction passage, and an O-ring interposed between the outer peripheral portion of the face plate and the movable portion. The movable portion moves, in the first direction, between a first position, at which the movable portion is coupled to the face plate by interposing the O-ring between the movable portion and the face plate and the gas introduction passage communicates with the inside of the chamber via the gas injection holes, and a second position, at which the movable portion is separated from the face plate and the gas introduction passage communicates with the inside of the chamber via a gap between the movable portion and the face plate
Implementation Method 2
an O-ring interposed between the outer peripheral portion of the face plate and the movable portion
Data Source
AI summary
A shower head includes a face plate having an outer peripheral portion and a plurality of gas injection holes disposed inside the outer peripheral portion, a movable portion facing the face plate and having a gas introduction passage, and a seal interposed between the outer peripheral portion of the face plate and the movable portion. The movable portion is arranged to move, in the first direction, between a first position in which the movable portion is coupled to the face plate by interposing the seal between the movable portion and the face plate, and the gas introduction passage communicates with the inside of the chamber via the gas injection holes, and a second position in which the movable portion is separated from the face plate, and the gas introduction passage communicates with the inside of the chamber via a gap between the movable portion and the face plate.