Probe Apparatus 3D Contact Position Correction
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Solution Overview
Problem
Existing probe apparatuses face challenges in achieving high accuracy for contact positions, particularly in the Z direction, when contacting probe needles with electrode pads on semiconductor wafers due to distortion and misalignment issues, leading to potential damage from incorrect overdrive and insufficient contact.
Innovation Solution
A probe apparatus that includes an imaging unit for capturing images of electrode pads and specific points on the substrate, with a storage unit for correction data obtained from a reference substrate, allowing for precise calculation and correction of contact positions in X, Y, and Z directions using relative positions and correction amounts, ensuring accurate alignment and contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coordinate correction is performed using only X and Y directions based on reference substrates, then alignment accuracy in horizontal plane is improved, but Z direction contact position accuracy remains insufficient
Solution Approach 1:
The patent extends coordinate correction from two dimensions (X-Y plane) to three dimensions by incorporating Z direction height information. A height map is generated for the substrate surface, and correction values are calculated for all three spatial dimensions. This allows the probe apparatus to compensate for substrate warpage and height variations, achieving accurate contact positioning in the Z direction alongside X and Y directions.
2Measurement precision
If ball screw distortion and mechanism vibration are considered in contact position calculation, then theoretical accuracy is improved, but actual contact precision deteriorates due to substrate warpage and height variations
Solution Approach 1:
The patent implements a feedback mechanism where the actual substrate surface topology is measured using imaging units, and this measured information is fed back into the coordinate correction calculation. The height map generated from imaging data provides real feedback about substrate warpage and height variations, which are then used to adjust contact positions dynamically, ensuring accurate alignment despite mechanical distortions.
Solution Approach 2:
The patent introduces a height map as an intermediary data structure that bridges the gap between theoretical calculations and actual substrate geometry. This height map serves as a mediator that captures the complex three-dimensional surface topology and translates it into correction values, allowing the system to account for substrate warpage without being directly affected by the complexity of mechanical distortions.
3Productivity
If probe needles contact electrode pads without Z direction correction, then operation speed is maintained, but contact accuracy and risk of damage increase
Solution Approach 1:
The patent performs coordinate correction calculations including Z direction information in advance, before the actual probing operation. The height map is generated and correction values are pre-calculated based on the substrate's three-dimensional topology. This preliminary action ensures that when the probe needles make contact, the positioning is already optimized for accurate Z direction alignment, maintaining high speed operation while achieving precise contact.
Data Source
AI summary
A probe apparatus for sequentially testing electrical characteristics of chips includes an imaging unit for capturing images of the electrode pads of the inspection substrate, and a unit for calculating contact positions at which the probes are expected to contact with the electrode pads. The probe apparatus further includes a storage unit for storing correction data in which reference points on a reference substrate are associated with correction amounts corresponding to differences between actual and calculated contact positions of the reference points, and a unit for obtaining actual contact positions for the electrode pads by measuring relative positions of the electrode pads with respect to the reference points and correcting the calculated contact positions of the electrode pads based on the relative positions and the correction data.