Thermal Control Unit Z-Axis Force Distribution
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Solution Overview
Problem
Thermal control units for IC devices face challenges in maintaining efficient heat transfer due to rigid mechanical designs that cause bending or bowing, leading to degraded thermal contact and instability, especially during cold testing where condensation can interfere with device functionality.
Innovation Solution
The implementation of a z-axis load distribution system that adjusts forces applied to different parts of the IC package, combined with swivelable fluid inlet and outlet arms and a condensation-abating gas system to prevent moisture accumulation, ensures stable and efficient thermal contact and reduces condensation-related issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rigid mechanical designs are used to generate high clamping forces for efficient heat transfer, then heat transfer efficiency is improved, but the components bend or bow causing degradation of thermal contact
Solution Approach 1:
The patent replaces rigid mechanical designs with dynamic compliant mechanisms including spring-loaded pedestals and flexible membranes that can adapt to thermal expansion and contraction. These compliant structures maintain stable thermal contact by flexing rather than bending, resolving the contradiction between generating sufficient clamping force and maintaining component integrity.
Solution Approach 2:
The patent changes the mechanical properties of components by introducing compliant materials and structures with appropriate flexibility parameters. The spring constants and material properties are optimized to provide sufficient clamping force for heat transfer while remaining within elastic limits to prevent permanent deformation, thus maintaining reliable thermal contact.
2Loss of energy
If high clamping forces are applied to maintain thermal contact, then heat transfer efficiency is improved, but components bend or bow interfering with thermal contact
Solution Approach 1:
The compliant mechanisms allow components to dynamically adjust their shape through elastic deformation within safe limits. The spring-loaded pedestals and flexible membranes can flex to accommodate thermal expansion without permanent bending, maintaining both heat transfer efficiency and component geometry.
Solution Approach 2:
The patent incorporates compliant elements that act as cushions before excessive forces can cause damage. The spring mechanisms and flexible membranes absorb and distribute clamping forces evenly, preventing localized stress concentrations that would lead to component bending or bowing.
3Strength
If rigid structures are used for thermal control, then mechanical strength is improved, but thermal contact stability during temperature changes deteriorates
Solution Approach 1:
The patent employs composite structures combining rigid support elements with compliant thermal contact surfaces. The rigid portions provide mechanical strength and structural integrity, while the compliant portions (springs, flexible membranes) maintain stable thermal contact by adapting to temperature-induced dimensional changes, resolving the contradiction between strength and thermal stability.
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 enhances thermal control unit stability and efficiency by distributing forces evenly across IC packages, maintaining precise temperature control and preventing condensation, thereby improving heat transfer and extending the life of thermoelectric devices.
Implementation Method 1
Peltier devices are solid-state devices that come in small thin geometries and that can be controlled by a DC current to pump heat away from a contacted device for removal. By reversing the current, the peltier device acts as a heater by pumping heat into a contacted device.
Implementation Method 2
a thermally-conductive electrically-resistive heater can be used to rapidly heat up the DUT
Implementation Method 3
rapidly cool down the DUT in combination a (cooling) fluid block, via conduction through the heater
Data Source
AI summary
Thermal control units (TCU) for maintaining a set point temperature on an IC device under test (DUT) are provided. The units include a pedestal assembly comprising a heat-conductive pedestal, a fluid circulation block, a thermoelectric module (Peltier device) between the heat-conductive pedestal and the block for controlling heat flow between the pedestal and fluid circulation block, and a force distribution block for controllably distributing a z-axis force between different pushers of the TCU. Alternatively, instead of a thermoelectric module, a heater can provide heat to the DUT. Optionally, a swivelable temperature-control fluid inlet and outlet arms may be provided to reduce instability of the thermal control unit due to external forces exerted on the TCU such as by fluid lines attached to the fluid inlet and outlet arms. Also optionally, an integrated means for abating condensation on surfaces of the TCU during cold tests may be provided.