Microcontroller Thermal Diode Feedback for IC Test Handler
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Solution Overview
Problem
Existing integrated circuit testing handlers lack real-time temperature control and are inadequate for mid-power devices with high self-heating, as they rely solely on airflow management, which fails to maintain accurate temperature guard bands and are costly for high-power devices.
Innovation Solution
A Cryogenic Temperature Control System (CTCS) that uses a microcontroller to read thermal diodes on high power devices, controlling a metering valve for liquid nitrogen or compressed air to regulate temperature, with a PID feedback control system for precise temperature management, allowing for real-time temperature monitoring and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If airflow management is used for thermal control, then device simplicity is maintained, but temperature control accuracy deteriorates for high power devices
Solution Approach 1:
The patent introduces a microcontroller as an intermediary component that reads the thermal diode and controls the metering valve based on temperature feedback. This intermediary enables precise temperature control without requiring complex hardware modifications to the entire system, resolving the contradiction between simplicity and accuracy.
Solution Approach 2:
The patent implements a feedback control system where the microcontroller continuously reads the thermal diode temperature and adjusts the metering valve accordingly. This closed-loop feedback mechanism achieves high temperature control accuracy while maintaining relative system simplicity through incremental enhancement rather than complete system redesign.
2Ease of manufacture
If existing handlers are used without modification, then system cost is reduced, but temperature control capability is insufficient for mid-power devices
Solution Approach 1:
The patent applies preliminary action by pre-cooling the device using liquid nitrogen or compressed air through the metering valve before thermal testing begins. This preparatory cooling action enables the existing handler to accommodate mid-power devices that generate significant heat during operation, improving temperature control capability without replacing the entire handler system.
Solution Approach 2:
The patent utilizes the device's own thermal diode for temperature sensing and control, allowing the device to essentially monitor and regulate its own temperature. This self-service approach eliminates the need for external temperature sensors and control systems, maintaining cost-effectiveness while improving reliability for mid-power device testing.
3Measurement precision
If real-time temperature control is implemented, then temperature accuracy is improved, but device complexity increases
Solution Approach 1:
The patent introduces a microcontroller as an intermediary component that reads the thermal diode and controls the metering valve based on temperature feedback. This intermediary enables precise temperature control without requiring complex hardware modifications to the entire system, resolving the contradiction between simplicity and accuracy.
Solution Approach 2:
The patent replaces complex mechanical temperature control systems with an electronic control approach using a microcontroller and software-based PID control. This substitution reduces mechanical complexity while achieving high temperature accuracy through electronic sensing and control algorithms.
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
The CTCS provides accurate and real-time temperature control for high power devices, reducing test time and costs by retrofitting existing handlers, enabling effective thermal management for devices in the mid-power range that previous systems could not handle.
Implementation Method 1
This microcontroller reads the DUT's thermal diode... Based on the DUT's internal die temperature
Implementation Method 2
The cooling fluid will be injected to the top of the device with a special pocketed nest and manifold system designed to create cooling fluid flow over much of the DUT top's surface area
Implementation Method 3
controlling a metering valve connected to an existing cooling fluid line (such as liquid nitrogen (LN2) or compressed air)
Data Source
AI summary
Production test of integrated circuit face thermal management challenges with higher power devices. Current production handlers do not have adequate thermal management characteristics. This invention employs thermal diodes on each device under test and a closed loop microprocessor controlled feedback system for thermal control during production test. The feedback system controls the open/close state of a valve supplying cooling fluid to bathe the integrated circuit based upon the difference between a temperature indicated by at least one thermal diode and a set point temperature.