Probe Apparatus Overdriving Correction via Laser Feedback
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Solution Overview
Problem
Conventional probe apparatuses face challenges in maintaining an accurate overdriving amount during semiconductor wafer testing due to deformation of the interface mechanism, leading to unreliable electrical contact and test results.
Innovation Solution
A probe apparatus equipped with distance measuring devices, such as laser beam distance measuring devices, to measure and correct the overdriving amount of the mounting table, ensuring it aligns with the preset overdriving amount, even when the interface mechanism deforms, by comparing the current overdriving amount with the preset value and adjusting accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mounting table is overdriven to bring the semiconductor wafer and probes into electrical contact, then reliable electrical contact is achieved, but the head plate deforms causing the actual overdriving amount to differ from the intended amount
Solution Approach 1:
The patent employs feedback control by measuring the actual overdriving amount with a distance measuring device and comparing it to the intended overdriving amount. The control unit then adjusts the mounting table's movement to compensate for head plate deformation, ensuring the actual overdriving amount matches the intended amount for reliable electrical contact.
Solution Approach 2:
The patent replaces direct mechanical measurement of overdriving amount with optical measurement using a laser beam distance measuring device. This substitution allows for precise, non-contact measurement of the actual overdriving amount without being affected by the mechanical deformation of the head plate.
2Force
If the probe card is lowered due to the load of the test head, then the interface mechanism can support the test head, but the central portion of the head plate deforms
Solution Approach 1:
The feedback mechanism continuously monitors the actual overdriving amount and compensates for head plate deformation caused by the test head load. The control unit adjusts the mounting table's position to maintain the correct overdriving amount despite the head plate's elastic deformation under load.
3Manufacturing precision
If the mounting table is raised to bring the semiconductor wafer into contact with the probe card, then alignment is achieved, but the probe card is slightly raised causing head plate deformation
Solution Approach 1:
The distance measuring device measures the actual overdriving amount after the mounting table is raised for contact. The control unit uses this feedback information to compensate for the head plate deformation caused by raising the mounting table, ensuring the intended overdriving amount is achieved for precise electrical contact.
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 solution enables highly reliable testing by maintaining an optimal overdriving amount, ensuring consistent and accurate electrical contact between the semiconductor wafer and the probes, despite deformation of the interface mechanism, thereby improving the reliability of the testing process.
Implementation Method 1
one or more distance measuring devices, such as laser beam distance measuring devices, for measuring a current overdriving amount of the mounting table
Data Source
AI summary
A probe apparatus includes a movable mounting table for supporting an object to be tested; a probe card disposed above the mounting table and having a plurality of probes to come into contact with electrodes of the object; a support body for supporting the probe card; and a control unit for controlling the mounting table. Electrical characteristics of the object are tested based on a signal from a tester by bringing the object and the probes into electrical contact with each other by overdriving the mounting table in a state where a test head is electrically connected with the probe card by a predetermined load. Further, one or more distance measuring devices for measuring a current overdriving amount of the mounting table are provided at one or more locations of the test head or the probe card.