Interposer Package for Burn-in Testing Thermal Stress Reduction
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Solution Overview
Problem
In burn-in tests for semiconductor integrated circuits, temperature changes cause stress that can lead to cracks in BGA packages bonded to burn-in boards, disrupting electrical connections and affecting test accuracy.
Innovation Solution
An interposer package is introduced, featuring a first substrate with a coefficient of expansion matching the burn-in board, a second substrate matching the BGA package, and a sheet contact for electrical connection. The package is sealed in a hard case to maintain pressure and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BGA package is directly bonded to burn-in board, then electrical connection is established, but stress and cracks occur due to temperature changes
Solution Approach 1:
An interposer substrate is introduced as an intermediary component between the BGA package and the burn-in board. This interposer substrate has a coefficient of thermal expansion that is intermediate between the BGA package and the burn-in board, thereby reducing thermal stress and preventing cracks while maintaining electrical connections through conductive via holes.
2Object-affected harmful factors
If interposer package is introduced to reduce stress, then crack formation is reduced, but device complexity increases
Solution Approach 1:
The package structure is segmented into three distinct parts: the BGA package, the interposer substrate, and the burn-in board. This segmentation allows each component to have optimized properties for its specific function, with the interposer substrate specifically designed to manage thermal expansion differences, thereby reducing crack formation while maintaining overall system functionality.
3Reliability
If mounting area is increased to accommodate interposer package, then stable electrical connection is achieved, but productivity decreases
Solution Approach 1:
The interposer substrate is designed as a thin film structure that provides the necessary mechanical and electrical functions without adding significant thickness or area. This thin film approach allows stable electrical connections to be achieved while minimizing the increase in mounting area, thereby maintaining high productivity and allowing for more simultaneous measurements.
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 interposer package effectively reduces stress and crack formation due to temperature changes, maintaining stable electrical connections between the BGA package and the burn-in board without increasing the mounting area, thus allowing for more simultaneous measurements.
Implementation Method 1
a first substrate (310) having a coefficient of expansion that is the same or substantially the same as a coefficient of expansion of a burn-in board (100); a second substrate (330) having a coefficient of expansion that is the same or substantially the same as a coefficient of expansion of a BGA package (400)
Data Source
AI summary
According to one embodiment, an interposer package disposed between a burn-in board and a test device package, includes: a first substrate having the same or substantially the same coefficient of expansion as a coefficient of expansion of the burn-in board; a second substrate having the same or substantially the same coefficient of expansion as a coefficient of expansion of the test device package; a first sheet contact inserted between the first substrate and the second substrate; and a case configured to seal the first substrate, the second substrate, and the first sheet contact. The first sheet contact is sandwiched between the first substrate and the second substrate, thereby electrically connecting the burn-in board and the test device packages to each other, and the first substrate, the second substrate, and the first sheet contact is sealed with the case applying a predetermined pressure, thereby maintaining the electrical connection.