Cover Part Design for Uniform Gas Diffusion in Shower Heads
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Solution Overview
Problem
Conventional substrate processing apparatuses face challenges in achieving uniform plasma distribution due to non-uniform gas supply through shower heads, leading to inconsistent plasma processing on wafers, especially when the internal space height is limited, hindering in-plane uniformity.
Innovation Solution
A cover part with a shielding portion facing the processing gas introducing pipe opening, allowing the gas to diffuse parallel to the substrate surface, increasing the internal space height for enhanced gas conductance and uniform supply, and a cylindrical design with through holes for perpendicular gas injection, ensuring uniform plasma distribution without dividing the internal space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a buffer plate is disposed within the internal space to diffuse processing gas, then gas distribution uniformity is improved, but the internal space height is reduced and gas conductance deteriorates
Solution Approach 1:
The patent transitions from horizontal gas diffusion (parallel to substrate) to vertical gas diffusion (perpendicular to substrate) by injecting gas through the bottom surface of the shower head. This dimensional change eliminates the need for buffer plates that reduce internal space height, while still achieving uniform gas distribution through the gas holes.
Solution Approach 2:
The patent introduces a diffuser structure at the bottom surface of the shower head as an intermediary component. This diffuser has multiple gas injection holes that distribute processing gas vertically before it enters the internal space, enabling uniform horizontal distribution without compromising the internal space height or gas conductance.
2Length of moving object
If the internal space height is limited, then the shower head thickness is reduced, but gas conductance and diffusion capability deteriorate
Solution Approach 1:
The patent maximizes the utilization of vertical space for gas injection while maintaining a thin overall profile. By injecting gas vertically from the bottom surface through a diffuser, the design achieves effective gas distribution in a compact thickness, improving gas conductance without increasing shower head thickness.
3Device complexity
If gas is injected directly downward through the introducing pipe, then the structure is simple, but gas distribution uniformity deteriorates
Solution Approach 1:
The patent introduces a diffuser as an intermediary component between the gas introducing pipe and the internal space. This diffuser has multiple injection holes arranged on its bottom surface, which distributes the gas flow uniformly in the vertical direction before it enters the internal space, achieving uniform gas distribution without significantly complicating the overall structure.
4Manufacturing precision
If buffer plates are used to prevent direct gas flow through gas holes, then gas supply uniformity is improved, but the internal space is divided and diffusion conductance is reduced
Solution Approach 1:
The patent extracts the gas distribution function from the internal space configuration and relocates it to a diffuser structure at the bottom surface. This eliminates the need for buffer plates that divide the internal space, maintaining a simple single-chamber configuration while achieving uniform gas supply through the gas holes.
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
The solution ensures uniform plasma processing by increasing gas conductance and supply uniformity, reducing non-uniformity in etching rates and enhancing in-plane uniformity of plasma processing, as confirmed by experimental results with a minimum internal space height of 8 mm.
Implementation Method 1
the processing gas introduced through the opening collides with the shielding portion to diffuse in substantially parallel to the surface of the substrate in the internal space
Implementation Method 2
the wafer is subjected to plasma processing by means of plasma generated from the processing gas in the processing space
Data Source
AI summary
A processing gas diffusing and supplying unit includes a supporting portion having an opening, a plate including gas supply holes, an internal space, between the supporting portion and the plate, communicating with the opening, and a cover part installed within the internal space and connected to the opening. The cover part includes a shielding portion which is disposed within the internal space and has a surface facing the opening, a side wall which holds the shielding portion, and a through hole formed at the side wall and communicating with the opening and the internal space. At least a portion of the gas supply holes is located right below the cover part and a height of the internal space is equal to or greater than 8 mm.