Cryogenic Wafer Test System Actuator Alignment
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Solution Overview
Problem
Testing superconducting circuits at cryogenic temperatures is expensive and labor-intensive, particularly due to the need for individual cooling of dice in liquid helium, which is not scalable for high-volume throughput.
Innovation Solution
A cryogenic wafer test system with a first chamber cooled to cryogenic temperatures and a wafer chuck actuator system providing translational and rotational motion to facilitate alignment and contact of electrical contacts with probe contacts, allowing for efficient testing of multiple superconducting dice on a wafer without the need for individual cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If individual dice are cooled in liquid helium for testing, then superconducting circuit testing can be performed, but the process becomes expensive and labor-intensive with low throughput
Solution Approach 1:
The patent merges multiple individual die testing operations into a single wafer-level operation. The wafer chuck holds an entire wafer with multiple superconducting die, and the cryogenic cooling system cools the entire wafer simultaneously rather than individual die, enabling high-volume throughput while maintaining superconducting testing capability
Solution Approach 2:
The wafer chuck serves multiple functions: it holds the wafer with multiple die, provides cryogenic cooling to the entire wafer, and enables mechanical alignment and positioning for probing. This multi-functional design eliminates the need for separate cooling fixtures for each die, significantly improving productivity
2Reliability
If individual dice are cooled in liquid helium for testing, then superconducting circuit testing can be performed, but the process becomes time-consuming
Solution Approach 1:
The wafer is pre-cooled to cryogenic temperatures before testing begins, and remains cooled throughout the testing process. This eliminates the need to repeatedly cool and warm individual die during testing, significantly reducing the time required for high-volume testing while maintaining superconducting functionality
Solution Approach 2:
The cryogenic cooling is maintained continuously throughout the entire testing process. The wafer remains at cryogenic temperature while multiple die are tested sequentially or in parallel, eliminating idle time for repeated cooling cycles and enabling continuous high-speed testing
3Reliability
If individual dice are cooled in liquid helium for testing, then superconducting circuit testing can be performed, but helium consumption becomes excessive
Solution Approach 1:
The cooling system is designed to cool the entire wafer with a single cryogenic cooling source rather than requiring separate cooling systems for each die. This dramatically reduces helium consumption by sharing the cooling resource across multiple die simultaneously tested on the wafer
Solution Approach 2:
The cryogenic cooling system is designed to maintain temperature efficiently throughout the testing process, minimizing helium loss. The system recovers and maintains cryogenic temperatures rather than requiring continuous replenishment of liquid helium for each individual die
4Temperature
If the wafer chuck is cooled to cryogenic temperatures, then superconducting die can be tested, but the actuator system would be damaged by extreme cold
Solution Approach 1:
The system is divided into two thermal zones: the wafer chuck and testing area are cooled to cryogenic temperatures, while the actuator system remains at room temperature. This segmentation allows each component to operate in its optimal temperature range, protecting the actuator from cryogenic damage while enabling superconducting die testing
Solution Approach 2:
A thermal barrier or insulation structure acts as an intermediary between the cryogenic wafer chuck and the room-temperature actuator system. This intermediary allows mechanical coupling for positioning while preventing thermal transfer that would damage the actuator components
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 significantly reduces testing time and helium consumption, enabling more efficient and scalable testing of superconducting circuits by maintaining the wafer at cryogenic temperatures while the actuator system operates at non-cryogenic temperatures, thus improving the efficiency and cost-effectiveness of the testing process.
Implementation Method 1
a first chamber that is cooled to a cryogenic temperature
Data Source
AI summary
One example includes a cryogenic wafer test system. The system includes a first chamber that is cooled to a cryogenic temperature and a wafer chuck confined within the first chamber. The wafer chuck can be configured to accommodate a wafer device-under-test (DUT) comprising a plurality of superconducting die. The system also includes at least one wafer prober configured to implement a test on a superconducting die of the plurality of superconducting die via a plurality of electrical probe contacts. The system further includes a wafer chuck actuator system confined within a second chamber. The wafer chuck actuator system can be configured to provide at least one of translational and rotational motion of the wafer chuck to facilitate alignment and contact of a plurality of electrical contacts of the superconducting die to the respective plurality of electrical probe contacts of the at least one wafer prober.