Work Press Assembly Thermal Expansion Management
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Solution Overview
Problem
Thermal management during integrated circuit (IC) testing poses challenges, particularly in the thermal expansion of work press assemblies in test handlers, which can lead to alignment issues and reliability problems.
Innovation Solution
The work press assembly is designed with a separation between the outer, alignment/guide region and the presser region, using materials with different coefficients of thermal expansion and thermal conductivity. Thermal insulation layers, such as fiberglass, are added to further reduce thermal conductivity and expansion in the alignment/guide region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the work press assembly uses a uniform thermally conductive material throughout, then thermal management of the device under test is improved, but thermal expansion causes alignment shifting and reliability degradation
Solution Approach 1:
The work press assembly is divided into distinct regions: a presser region made of thermally conductive material for thermal management, and an alignment/guide region made of thermally insulating material for dimensional stability. This segmentation allows each region to perform its specific function without being adversely affected by thermal expansion, resolving the contradiction between thermal management and alignment stability.
Solution Approach 2:
Different materials with different thermal properties are used in different locations of the work press assembly. The presser region uses thermally conductive material where heat transfer is needed, while the alignment/guide region uses thermally insulating material where dimensional stability is critical. This local differentiation resolves the contradiction by optimizing each region for its specific function.
2Reliability
If thermal insulation layers are added to reduce thermal conductivity, then alignment stability is improved, but device complexity increases
Solution Approach 1:
The thermally insulating alignment/guide region is nested within or integrated with the presser region in a compact configuration. The guide frame with guide holes is positioned to receive guide pins from the socket, with thermal insulation layers strategically placed to minimize heat transfer paths while maintaining structural integrity and alignment functionality, thus reducing the impact on device complexity.
Solution Approach 2:
Thermal insulation layers act as intermediary elements between the thermally conductive presser region and the thermally sensitive alignment/guide region. These insulation layers (such as fiberglass or air gaps) mediate the thermal interaction, blocking heat transfer to the alignment region while allowing the presser region to maintain thermal contact with the device under test, thus improving alignment stability with minimal added complexity.
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 design reduces thermal expansion and lateral shifting of the alignment/guide means, enhancing the reliability of the work press assembly and minimizing damage to tested devices.
Implementation Method 1
Thermal insulation layers, such as fiberglass, are added to further reduce thermal conductivity and expansion in the alignment/guide region
Implementation Method 2
The guide frame is formed from a second material having a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion
Data Source
AI summary
An exemplary work press assembly for a test handler includes a presser and a guide frame. The presser is configured to secure a device under test (DUT) and press the DUT into a socket for testing. The guide frame is configured to receive guide pins of the socket. The presser extends through an opening of the guide frame, and the guide frame is sandwiched between a first presser portion and a second presser portion. The presser is formed of a first material having a first coefficient of thermal expansion (CTE), and the guide frame is formed from a second material having a second CTE that is less than the first CTE. In some embodiments, a thermal insulation layer(s) separates the presser from the guide frame. In some embodiments, a spacing between sidewalls of the presser and sidewalls of the guide frame is configured to accommodate thermal expansion of the presser.