Electrostatic Chuck Staged Clamping for Uniform Wafer Stress
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Solution Overview
Problem
The challenge in semiconductor fabrication is to securely clamp semiconductor wafers on electrostatic chucks while minimizing stress concentration and friction, which can lead to contamination and processing errors due to warpage and uneven clamping.
Innovation Solution
The electrostatic chuck clamps the semiconductor wafer in at least two stages, allowing the wafer to be fully extended and reducing stress concentration and contamination by gradually applying electrostatic force across the wafer and chuck surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrostatic chuck clamps the wafer using a single stage with uniform voltage, then the clamping force is strong and secure, but stress concentration and friction increase leading to warpage and contamination
Solution Approach 1:
The chuck electrode is divided into multiple independently controllable regions (first chuck region, second chuck region, third chuck region) that can be controlled at different voltage levels. This segmentation allows differential voltage application to achieve uniform stress distribution across the wafer surface while maintaining secure clamping, resolving the contradiction between strong clamping force and stress uniformity.
2Force
If the electrostatic chuck applies high voltage to secure the wafer, then the clamping force increases, but friction and contamination risk increase
Solution Approach 1:
Different voltage levels are applied to different chuck regions based on local requirements. The first chuck region receives a first voltage level, the second chuck region receives a second voltage level, and the third chuck region receives a third voltage level. This local quality approach optimizes clamping force in each region while minimizing overall friction and contamination risk.
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 staged clamping process effectively reduces stress concentration and contamination, ensuring a more secure and even clamping of the semiconductor wafer, which enhances processing accuracy and reduces the risk of damage.
Implementation Method 1
securing the wafer to the electrostatic chuck by: securing a first wafer region of the wafer to a first chuck region of the electrostatic chuck by applying a first voltage
Data Source
AI summary
A method includes: positioning a wafer on an electrostatic chuck of an apparatus; and securing the wafer to the electrostatic chuck by: securing a first wafer region of the wafer to a first chuck region of the electrostatic chuck by applying a first voltage at a first time. The method further includes securing a second wafer region of the wafer to a second chuck region of the electrostatic chuck by applying a second voltage at a second time different from the first time; and processing the wafer by the apparatus while the wafer is secured to the electrostatic chuck.