Optical Probe Gap Alignment Using Imaging Feedback
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Solution Overview
Problem
Existing probe systems struggle to maintain precise gap spacing between optical probes and optical devices in device under test (DUT) due to the need for greater accuracy than electrical contact, especially when accessing optical devices below the substrate surface.
Innovation Solution
A probe system with an optical imaging device and controller that adjusts the relative orientation of the optical probe using an electrically actuated positioning assembly to maintain a desired gap spacing based on focal length and optical observations, utilizing distance sensors and fiducial marks for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrical probe systems are used, then electrical contact is maintained, but gap spacing control accuracy is insufficient for optical devices
Solution Approach 1:
The patent replaces the mechanical/electrical probe contact system with an optical imaging-based measurement and control system. Instead of using physical contact to maintain positioning, the system uses optical imaging to detect gap spacing and controls the probe position based on imaging data, achieving micrometer-level accuracy without mechanical contact
Solution Approach 2:
The patent implements a feedback control system where the optical imaging device continuously monitors the gap spacing between the optical probe and the optical device, and the controller adjusts the probe position based on this feedback to maintain the desired gap spacing, enabling precise control during temperature changes and testing
2Measurement precision
If optical probes are positioned close to optical devices for accurate testing, then measurement accuracy improves, but alignment stability deteriorates during temperature changes
Solution Approach 1:
The patent uses continuous optical imaging feedback to monitor and maintain the gap spacing between the optical probe and optical device. The controller adjusts the probe position in real-time based on imaging data, compensating for thermal expansion and alignment drift during temperature changes, thus maintaining both close proximity for accuracy and stability through active control
Solution Approach 2:
The patent dynamically adjusts the gap spacing parameter based on temperature conditions and optical feedback. The system modifies the probe position and gap distance in response to changing thermal conditions, allowing the system to maintain optimal testing accuracy across varying temperatures by adapting the geometric parameters
3Manufacturing precision
If manual alignment methods are used, then device complexity is reduced, but alignment precision and repeatability are insufficient
Solution Approach 1:
The patent replaces manual mechanical alignment with an automated optical imaging and control system. The optical imaging device captures images of alignment marks, and the controller automatically calculates and adjusts the probe position based on image analysis, achieving high precision and repeatability without manual intervention
Solution Approach 2:
The patent implements self-alignment functionality where the system automatically determines its own position and orientation using optical imaging of fiducial marks on the device under test. The controller processes the imaging data and autonomously adjusts the probe alignment, enabling the system to self-correct and maintain precision without external manual adjustment
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
Achieves precise control of gap spacing to within micrometer levels, enhancing the accuracy of optical testing by maintaining consistent alignment during temperature changes and optical signal transmission.
Implementation Method 1
an optical imaging device to observe the optical probe and the device under test
Implementation Method 2
optical images of the optical probe and the device under test
Data Source
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AI summary
Methods for maintaining gap spacing between an optical probe of a probe system and an optical device of a device under test and probe systems that perform the methods. The methods include determining a desired relative orientation between the optical probe and the DUT and optically testing the optical device with the optical probe. The methods also include maintaining the desired relative orientation during the optically testing. The maintaining includes repeatedly and sequentially collecting an existing DUT image of a DUT reference structure of the DUT and an existing probe image of a probe reference structure of the optical probe, determining a probe-DUT offset between an existing relative orientation between the optical probe and the DUT and the desired relative orientation, and adjusting the relative orientation to return the optical probe and the DUT to the desired relative orientation.