Self-Aligning Lift Pin Assembly for Substrate Processing
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Solution Overview
Problem
In substrate processing apparatuses, misalignment between the upper and lower parts of the electrostatic chuck can cause lift pins to tilt, leading to stress concentration and potential breakage due to interference with the substrate plate, resulting in particle generation and wafer sticking.
Innovation Solution
A lift pin assembly with a pin connection block and lift pin holder that allows for self-alignment by eccentric movement in the horizontal direction, preventing tilting and limiting vertical movement to prevent wafer sticking, featuring guide recesses and sliding portions for precise alignment and stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lift pins are installed in the substrate plate with standard machining tolerances, then the device complexity is reduced and ease of manufacture is improved, but misalignment between upper and lower parts causes lift pin tilting leading to stress concentration and potential breakage
Solution Approach 1:
The patent introduces guide recesses and sliding portions that change the geometric parameters of the lift pin assembly, allowing horizontal adjustment to compensate for misalignment while maintaining vertical lifting function. This resolves the contradiction by enabling tolerance compensation without requiring ultra-precise machining.
Solution Approach 2:
The guide recesses and sliding portions act as intermediary elements between the lift pin and substrate plate, providing a self-aligning mechanism that mediates the misalignment issue. These intermediaries allow the lift pin to automatically adjust its position horizontally to achieve proper alignment during operation.
2Reliability
If lift pins are made fixed to prevent tilting, then reliability is improved by preventing breakage, but the device complexity increases due to additional alignment mechanisms
Solution Approach 1:
The lift pin assembly performs self-alignment through the guide recesses and sliding portions, eliminating the need for external complex alignment mechanisms. The structure automatically compensates for misalignment during operation, achieving reliability improvement without proportionally increasing device complexity.
Solution Approach 2:
The patent introduces dynamic elements (sliding portions that can move horizontally) into the previously static lift pin structure. This allows the assembly to adapt to misalignment conditions dynamically, providing reliability without requiring overly complex fixed alignment mechanisms.
3Stability of the object's composition
If the lift pin holder is rigidly connected to the pin connection block, then structural stability is improved, but misalignment causes tilting and interference with the substrate plate
Solution Approach 1:
The patent segments the connection between the lift pin holder and pin connection block by introducing guide recesses and sliding portions. This segmentation allows the structure to maintain overall stability while enabling local horizontal adjustment to prevent tilting and interference with the substrate plate.
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 self-aligning mechanism ensures the lift pin moves vertically without tilting, preventing breakage and wafer sticking, even with misalignment, thereby enhancing the reliability and efficiency of substrate processing.
Implementation Method 1
a first sliding portion to be received movably in the second direction within the first guide recess by an eccentricity distance of the second longitudinal axis from the first longitudinal axis
Data Source
AI summary
A lift pin assembly includes a lift pin having a first longitudinal axis substantially parallel with a first direction, a pin connection block combined with a lower end portion of the lift pin and including a first guide recess in a lower end portion of the pin connection block, the first guide recess extending in a second direction substantially perpendicular to the first direction, and a lift pin holder having a second longitudinal axis substantially parallel with the first direction and including a first sliding portion to be received movably in the second direction within the first guide recess by an eccentricity distance of the second longitudinal axis from the first longitudinal axis when the lift pin holder is connected to the lower end portion of the pin connection block.