Reversible Wafer Rack Design for Erosion Mitigation
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Solution Overview
Problem
The existing vertical wafer boats used in thin film formation processes are prone to erosion due to particles or chemicals in diffusion devices, leading to increased costs from frequent replacements.
Innovation Solution
A vertical wafer boat design featuring a plurality of wafer racks with vertical support members and wafer support arms, where each support arm includes a support body and a ledge with specific geometric alignments and dimensions, allowing for horizontal alignment of centers and varying thicknesses, and the ability to reverse the wafer rack for extended use by switching contact sides to mitigate erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vertical wafer boat is used in diffusion devices, then the thin film formation process can be performed, but particles or chemicals cause erosion to the slots leading to frequent replacement
Solution Approach 1:
The wafer rack is designed to be reversible, allowing it to be flipped 180 degrees and reused. The first and second contact sides are symmetrically designed with identical ledge structures, enabling the rack to be inverted and the opposite side to become the new contact surface. This inversion strategy extends the service life by utilizing both sides of the rack, effectively doubling its usable lifespan before replacement is needed.
Solution Approach 2:
Instead of discarding the entire wafer rack when one contact side becomes eroded, the invention allows recovery by flipping the rack to use the other contact side. The non-contact side serves as a reserve that can be activated when the contact side wears out, thereby recovering the remaining useful life of the component and reducing replacement frequency.
2Productivity
If the wafer boat slots are exposed to diffusion device environment, then wafers can be processed, but the slots suffer from chemical and particle erosion
Solution Approach 1:
The wafer rack is designed with symmetrical contact sides that can be inverted. When one contact side becomes eroded from exposure to the diffusion device environment, the rack can be flipped 180 degrees to present the other contact side for use. This maintains productivity while protecting against the cumulative effects of erosion on any single contact surface.
3Reliability
If frequent replacement of wafer boat is performed, then erosion damage is avoided, but the cost of thin film formation process increases
Solution Approach 1:
By designing the wafer rack with reversible symmetry, the invention allows each rack to serve twice as long as traditional single-sided racks. The rack can be flipped to use the opposite contact side when erosion occurs, effectively doubling the service life and halving the replacement frequency, thereby reducing overall operational costs.
Solution Approach 2:
Instead of discarding the wafer rack when one contact side is eroded, the invention recovers value by flipping to the unused contact side. This extends the functional life of each rack unit, reducing the number of racks that need to be manufactured and disposed of, thus lowering material and manufacturing costs.
Data Source
AI summary
A vertical wafer boat for a diffusion process is provided. The vertical wafer boat includes a plurality of wafer racks. Each of the plurality of wafer racks includes a vertical support member and a plurality of wafer support arms. The plurality of wafer support arms extends from a sidewall of the vertical support member. Each of the wafer support arms includes a support body and a ledge. The support body is located between the vertical support member and the ledge. Centers of the support body and the ledge are horizontally aligned. A vertical thickness of the ledge is smaller than a vertical thickness of the support body.