Asymmetrical Horizontal Substrate Carrier for Thermal Processing
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Solution Overview
Problem
Existing horizontal substrate carriers for thermal processing suffer from substrate movement and particle contamination due to vibration, which leads to angular rotation and tilting, making it difficult to maintain precise vertical positioning and increasing particle formation during robotic loading and unloading.
Innovation Solution
An asymmetrical horizontal substrate carrier design with a high-angle upper rail on one side and no upper rail on the other, combined with two lower rails, minimizes substrate movement and contact points, allowing for precise vertical holding and easy robotic access, reducing particle contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If substrates are held in slots of upper and lower rails with ±2 to 3 degrees vertical tolerance, then substrates can be loaded into the carrier, but vibration causes substrates to rattle and angularly rotate, leading to particle contamination
Solution Approach 1:
The patent applies asymmetry by positioning the upper rail at a high angular location (60° or more, preferably 70° or more, most preferably 90° or greater) on one side of the carrier while leaving the other side without a corresponding upper rail. This asymmetric configuration creates a more stable substrate holding position that reduces rattling and angular rotation during vibration, thereby minimizing particle contamination while maintaining ease of robotic loading.
2Reliability
If four rails (two upper and two lower) are used to hold substrates, then substrates are securely positioned, but robotic loading becomes more difficult due to limited access
Solution Approach 1:
The patent applies the extraction principle by removing one upper rail from the traditional four-rail configuration, leaving only one upper rail on one side of the carrier. This reduction in the number of rails simplifies the overall structure and creates easier access for robotic loading mechanisms while maintaining sufficient substrate holding stability through the optimized positioning of the remaining rails.
3Ease of operation
If upper rail is positioned at low angular location for easy robotic access, then robotic loading is easier, but substrate vertical holding precision decreases and substrates rattle more during vibration
Solution Approach 1:
The patent resolves this contradiction by applying asymmetry - positioning the single upper rail at a high angular location (60° or more) on one side of the carrier. This high-angle positioning improves vertical holding precision and reduces substrate rattling during vibration, while the asymmetric design (with no corresponding upper rail on the other side) maintains ease of robotic loading by providing adequate access space.
Data Source
AI summary
A horizontal substrate carrier is provided, for example a carrier for holding semiconductor substrates during horizontal thermal processing. The horizontal substrate carrier has asymmetrically placed support rails. One side of the horizontal substrate carrier has no upper rail while the other side of the horizontal substrate carrier has an upper rail placed at a relatively high location, for example at an angular location of 60° or more, more preferably of 70° or more, and most preferably at 90°. The side without an upper rail may be used for robotic loading of the horizontal substrate carrier. In a preferred embodiment, only three rails are provided: one upper rail on one side and two lower rails. The use and placement of these three rails can hold the substrate in precise uniform locations, minimize substrate movement, and minimize particle generation, all while allowing for easy robotic access.