Wafer Support Structure for Accurate Geometry Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wafer chucks alter the bow of the wafer due to suction and gravitational forces, affecting the accuracy of wafer geometry measurements.
Innovation Solution
A wafer measurement stage with a support body and a wafer contact structure that elevates the wafer, controlling gravity effects at non-contact portions and allowing for mathematical removal of these effects from geometry measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wafer chuck is used to hold the wafer during measurement, then the wafer is securely supported, but the suction and gravitational forces alter the wafer bow, reducing measurement accuracy
Solution Approach 1:
The support surface is segmented into multiple discrete contact elements (pins or points) rather than a continuous suction surface. This segmentation allows the wafer to be supported at specific locations while leaving other areas free, minimizing the overall gravitational distortion across the wafer surface while maintaining secure support at contact points.
Solution Approach 2:
The harmful suction force is extracted/removed from the system. Instead of using a chuck with suction that applies distributed force across the wafer back surface, the invention uses passive gravitational support through discrete contact points, eliminating the suction mechanism that causes unwanted wafer deformation.
2Stability of the object's composition
If the wafer is fully supported on a planar surface, then the wafer is stable, but gravity causes sagging at non-contact portions, distorting the wafer geometry
Solution Approach 1:
The continuous planar support surface is segmented into discrete contact points or pins. This segmentation creates specific support locations that maintain wafer stability through gravitational contact while leaving intervening areas unsupported, allowing those portions to naturally assume their true geometric position without gravity-induced sagging against a continuous surface.
Solution Approach 2:
Different regions of the wafer have different support conditions: contact regions provide stable gravitational support while non-contact regions remain free. This local differentiation in support quality allows the measurement system to capture the true wafer geometry in non-contact areas while maintaining overall stability through contact points.
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 solution minimizes alterations to wafer geometry caused by gravity, enhancing the accuracy of wafer geometry measurements and enabling precise correction of wafer bow.
Implementation Method 1
control gravity effects at non-contact portions of the wafer
Data Source
AI summary
A wafer measurement stage for supporting a semiconductor wafer for surface geometry measurements. The wafer measurement stage includes a support body having a planar surface configured to face a wafer which is supported by the wafer measurement stage, and a wafer contact structure provided on the planar surface. The wafer contact structure is configured to contact a portion of a wafer such that the wafer is supported in an elevated position relative to the planar surface and to control gravity effects at non-contact portions of the wafer.