Triangular Cross-Section Lift Pin for Uniform Substrate Heat Transfer
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Solution Overview
Problem
Conventional lift pins in substrate support assemblies generate particles and fail to transfer heat uniformly to semiconductor substrates, leading to hot spots and cold spots during thermal processing.
Innovation Solution
The design of lift pins with a pin shaft having a cross-section of at least three equal edges and round corners, and a convex pin head with a flat central portion for direct substrate contact, reduces particle generation and enhances heat transfer by minimizing friction and ensuring uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional lift pins with circular cross-section are used, then the lift pin can move smoothly through the guide hole, but particle contamination is generated due to contact between the lift pin and guide hole
Solution Approach 1:
The lift pin shaft is designed with a triangular cross-section instead of a circular one. This asymmetric shape allows the pin to rotate within the circular guide hole while maintaining minimal contact points, reducing friction and particle generation during movement.
2Device complexity
If conventional lift pins with uniform cross-section are used, then the structure is simple, but heat transfer to the substrate is non-uniform causing hot spots and cold spots
Solution Approach 1:
The lift pin is designed with different cross-sectional shapes at different locations: the shaft has a triangular cross-section for low-friction movement, while the head has a circular cross-section with a flat bottom surface for uniform heat transfer to the substrate. This local differentiation allows each part to optimize its function.
Solution Approach 2:
The invention transitions from a uniform one-dimensional cross-section to a two-dimensional variation in cross-sectional shape along the length of the lift pin. The shaft portion uses triangular geometry while the head portion uses circular geometry, creating a multi-dimensional structural solution that addresses both movement and heat transfer requirements.
3Use of energy by moving object
If lift pins with large contact area are used, then heat transfer efficiency is improved, but particle generation increases due to increased contact with guide hole
Solution Approach 1:
The lift pin shaft is designed with a triangular cross-section that minimizes contact with the guide hole walls during movement, reducing particle generation. The head is designed with a circular cross-section and flat bottom surface that provides large contact area with the substrate for efficient heat transfer. This local differentiation resolves the contradiction between contact area and particle generation.
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 design reduces particle contamination and achieves uniform heat distribution across the substrate, preventing hot spots and cold spots, thereby improving the substrate support assembly's efficiency in semiconductor processing.
Implementation Method 1
A flat portion is disposed on a central area of the convex support surface for directly contacting the substrate
Implementation Method 2
The pin shaft includes a cross-section having at least three equal edges and round corners configured alternatively
Data Source
AI summary
A lift pin is provided for manipulating a substrate above a support surface of a substrate support and uniformly transferring heat from the substrate support to the substrate. The lift pin includes a pin shaft. The pin shaft includes a cross-section having at least three equal edges and round corners configured alternatively. A pin head is an end portion of the pin shaft, wherein the pin head has a convex support surface larger than the cross-section of the pin shaft. A flat portion is disposed on a central area of the convex support surface for directly contacting the substrate.