Wafer Probe Alignment via Corner Delta Adjustment
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Solution Overview
Problem
Existing wafer probe alignment methods face challenges in maintaining planarity between the test board contacts and the wafer, leading to potential contact loss and unreliable test results due to mechanical distortion and the need for manual adjustments, which can impact mechanical stability and are prone to errors.
Innovation Solution
A method where at least two corners of the probe are adjustable in the same direction relative to a primary corner, with a grid of signal pins adjusted based on contact force to establish electrical connections, allowing for real-time compensation of mechanical tolerances and potential oxide burning for improved contact reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual adjustment mechanism is inserted to correct planarity during contacting, then planarity between wafer and probe contacts is improved, but mechanical stability deteriorates and operation complexity increases
Solution Approach 1:
The system performs preliminary measurement of the wafer surface topography before contacting, and pre-calculates the required adjustment amounts for each probe contact. This allows the adjustment mechanism to be positioned optimally in advance, minimizing mechanical instability during actual contacting operation.
Solution Approach 2:
The patent replaces manual mechanical adjustment with an automated adjustment mechanism that uses measurement data to automatically position probe contacts. This substitution eliminates the need for operators to manually manipulate adjustment mechanisms during contacting, thereby maintaining mechanical stability while achieving precise planarity correction.
2Manufacturing precision
If adjustment mechanism is operated manually to correct planarity, then planarity is improved, but operation complexity and error probability increase
Solution Approach 1:
The adjustment mechanism is designed to automatically correct planarity deviations based on measurement data without requiring manual intervention. The system self-adjusts the probe contact positions according to the calculated correction values, eliminating operator involvement in the adjustment process and thereby reducing operation complexity and error probability.
Solution Approach 2:
The system uses measurement data from the wafer surface topography as feedback to automatically control the adjustment mechanism. This closed-loop feedback system eliminates the need for manual trial-and-error adjustment, significantly simplifying the operation while ensuring accurate planarity correction.
3Reliability
If contact force is applied to establish electrical contacts, then electrical contact reliability is improved, but mechanical distortion of wafer probe increases
Solution Approach 1:
The system pre-measures the wafer surface topography and pre-calculates the optimal contact force distribution for each probe contact based on the measured surface variations. This allows the application of precisely controlled contact forces that are sufficient to ensure reliable electrical contact while minimizing excessive forces that would cause mechanical distortion of the wafer probe.
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 approach ensures accurate alignment and reliable electrical contact between signal pins and contact pads, reducing the need for additional alignment tools and foils, and enhancing test results by directly measuring and adjusting for mechanical distortions and oxide presence.
Implementation Method 1
the wafer is held, for example, by vacuum on a chuck
Implementation Method 2
determining for each signal pin whether an electrical contact may be established to a corresponding contact pad of the chip under contact force
Data Source
AI summary
A wafer probe alignment system and method for aligning a probe to a chip wafer for testing a chip on the wafer are provided. At least two corners of the probe are adjustable in a same direction in relation to a primary corner of the probe. The alignment approach includes providing a grid of signal pins for corresponding contact pads of the chip under test, determining for each signal pin whether an electrical contact is established to a corresponding contact pad of the chip under contact force, and adjusting a position of each of the at least two corners by a corner individual delta position value with respect to the direction depending on a result of the determining in order to establish an electrical contact between each of the pins and the corresponding contact pads of the chip under test.