Wafer-Scale Thermal Interposer for Independent Die Temperature Control
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Solution Overview
Problem
Conventional environmental testing of integrated circuits is limited by the need for chamber-based systems that degrade accuracy, are slow due to large volumes and mass, and lack precise control over individual die temperatures, especially in wafer-level testing.
Innovation Solution
A wafer scale active thermal interposer device with independently controllable heating and cooling zones, powered by pulse width modulation, allows for precise temperature control of different portions of a wafer, compatible with existing testing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chamber-based environmental testing systems are used, then integrated circuits can be tested under controlled environmental conditions, but the testing accuracy is degraded due to environmental limits of test interface circuits and devices
Solution Approach 1:
The patent extracts the thermal control function from the environmental chamber and integrates it directly into the interposer device. The interposer includes heating elements and cooling structures that can independently control temperatures of individual dice, eliminating the need for chamber-based environmental control and its associated accuracy limitations.
Solution Approach 2:
The interposer acts as an intermediary between the dice and the test system. It provides direct thermal control to the dice through integrated heating and cooling structures, serving as a mediator that eliminates the environmental chamber's thermal control limitations while maintaining test interface functionality.
2Productivity
If large volume environmental chambers are used, then integrated circuits can be tested under environmental conditions, but the rate of testing is limited due to large volumes of air and mass of mounting structures
Solution Approach 1:
The patent extracts the thermal control functionality from the large-volume environmental chamber and relocates it to a compact interposer device. This eliminates the thermal mass and air volume limitations of chambers, enabling rapid temperature changes and high-speed testing.
Solution Approach 2:
The patent replaces the mechanical thermal control system of environmental chambers with integrated electronic heating elements and cooling structures on the interposer. This substitution enables faster response times and eliminates the inertia associated with large chamber masses.
3Measurement precision
If conventional cooling structures with cooling fluid circulation are used, then integrated circuits can be cooled during testing, but precise temperature control of individual dice is not available
Solution Approach 1:
The patent segments the thermal control system into independent zones corresponding to individual dice or groups of dice on the wafer. Each zone can be independently controlled with its own heating elements and cooling channels, enabling precise temperature control of individual dice while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent implements local thermal control by providing independent heating and cooling capabilities to different regions of the wafer. Each die or group of dice can have its temperature independently adjusted to specific test requirements, creating local thermal environments optimized for individual testing needs.
4Productivity
If wafer-level testing is performed, then manufacturing throughput is increased and defective dies can be identified early, but precise heating and cooling of individual die within a wafer is not available
Solution Approach 1:
The interposer divides the wafer into multiple independently controllable thermal zones, each corresponding to one or more individual dice. This segmentation enables wafer-level testing with precise individual die temperature control, maintaining high throughput while achieving the required thermal precision.
Solution Approach 2:
The interposer provides universal thermal control capabilities across the entire wafer, with each zone capable of independent heating and cooling. This multi-functional design enables simultaneous testing of multiple dice at different temperatures, maximizing manufacturing throughput while maintaining individual die temperature precision.
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
Enables rapid and accurate environmental testing of integrated circuits at the wafer level, identifying defective dies and increasing manufacturing throughput by allowing differential temperature control of individual dice.
Implementation Method 1
a plurality of independently controllable heating zones... configured to maintain or change temperatures on the top surface
Implementation Method 2
a plurality of independently controllable cooling zones configured to maintain or change temperatures on the top surface
Data Source
AI summary
A system for testing circuits of an integrated circuit semiconductor wafer includes a test stack for use in testing circuits of an integrated circuit component includes a top surface configured to receive the component in proximity thereto, a plurality of independently controllable thermal zones including a plurality of independently controllable heating zones and a plurality of independently controllable cooling zones configured to maintain or change temperatures on the top surface, and a power input configured to receive electrical power and wherein the electrical power is configured to be selectively applied to one or more of the plurality of independently controllable heating zones.