Wafer Test Stage Attitude Control for Load Equalization
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Solution Overview
Problem
Existing testing apparatuses face challenges in evenly distributing the load applied to the base of the stage due to the large number of contact probes, leading to potential tilting and instability during wafer testing.
Innovation Solution
A stage design incorporating four movable bodies supported by independent driving motors, guided by parallel guides within a continuous support frame, allows for precise adjustment of the base's attitude to equalize loads, using torque sensors and controllers to correct any tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large number of contact probes are used to test the wafer, then testing capability is improved, but load distribution on the base deteriorates
Solution Approach 1:
The base is divided into multiple independently controllable segments (first base segment and second base segment) that can be adjusted relative to each other. This segmentation allows independent positioning of different base regions to compensate for load imbalances caused by multiple contact probes, thereby maintaining both high testing capability and stable load distribution.
Solution Approach 2:
The base structure is made dynamically adjustable through driving mechanisms that can change the relative positions of base segments in real-time. This dynamic adjustment capability enables the system to adapt to varying load distributions during testing, maintaining stability even when using a large number of contact probes.
2Device complexity
If the base attitude is not adjusted, then device simplicity is maintained, but testing accuracy deteriorates
Solution Approach 1:
The base attitude adjustment mechanism provides dynamic control over base orientation and position. By enabling real-time adjustment of base segments, the system achieves high testing accuracy without requiring an overly complex fixed structure, balancing simplicity with precision.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor base attitude and load distribution, automatically adjusting base segment positions to maintain optimal testing conditions. This feedback control ensures testing accuracy while keeping the overall device design relatively simple through automated compensation.
Data Source
AI summary
A stage includes a base on which an object to be transported or tested is placed, four movable bodies configured to support the base in a manner so that the base can be raised and lowered, four driving motors, provided in correspondence with the four movable bodies, and configured to independently raise and lower the four movable bodies, respectively, four guides configured to guide the four movable bodies, respectively, and a support frame, having wall surfaces parallel to a raising and lowering direction of the base and continuous along a direction perpendicular to the raising and lowering direction of the base, and the four guides fixed to the wall surfaces.