Compliant Base Frame Interconnection for IC Package Stacking
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Solution Overview
Problem
The existing integrated circuit packaging systems face challenges with solder cracking due to thermal mismatch between semiconductor chips and substrates, leading to reduced reliability and increased manufacturing complexity, especially in multichip modules, where mechanical stress and heat dissipation issues exacerbate the problem.
Innovation Solution
The integrated circuit package stacking system involves forming a base frame with coupling pads, mounting pads, and base frame traces on a support panel, coupling an integrated circuit die to a package substrate, and removing the support panel to create a low-profile, highly compliant interconnection scheme that simplifies assembly and reduces thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder connections are used to interconnect chip contacts to substrate, then electrical connection is achieved, but solder cracking occurs due to thermal mismatch stress
Solution Approach 1:
The patent introduces a compliant interconnection structure as an intermediary between the chip and substrate. This intermediate layer absorbs thermal expansion differences through its compliance, preventing stress transmission to the solder joints. The compliant structure acts as a buffer that decouples the thermal mismatch problem from the solder connections.
Solution Approach 2:
The patent changes the mechanical parameters of the interconnection system by introducing compliance into the interconnection structure. This compliance allows the system to accommodate thermal expansion variations without generating excessive stress, thereby preventing solder cracking while maintaining electrical connectivity.
2Adaptability or versatility
If multiple semiconductor chips are packaged together in multichip modules, then functional integration is improved, but thermal stress and manufacturing complexity increase
Solution Approach 1:
The patent divides the multichip module into modular units, each with its own compliant interconnection structure. This segmentation allows each chip to be independently packaged and tested before assembly, simplifying manufacturing. The modular approach enables easier replacement and reconfiguration of individual chips without affecting the entire module.
Solution Approach 2:
The patent implements preliminary testing and packaging of individual chips before final module assembly. By pre-packaging and pre-testing chips separately, manufacturing defects can be identified early, and only verified good chips are assembled into the final module, thereby simplifying overall manufacturing processes and improving yield.
3Area of stationary object
If chip features are reduced in size to increase packing density, then area efficiency is improved, but thermal mismatch stress increases
Solution Approach 1:
The patent changes the mechanical compliance parameter of the interconnection structure to compensate for increased thermal mismatch stress resulting from smaller chip sizes. The compliant structure adapts its mechanical properties to accommodate the higher stress concentrations that arise from reduced chip dimensions and increased packing density.
Data Source
AI summary
A method of manufacture of an integrated circuit package stacking system including: forming a base frame includes: providing a support panel, and forming a coupling pad, a mounting pad, a base frame trace, a discrete component pad, or a combination thereof on the support panel; fabricating a package substrate; coupling an integrated circuit die to the package substrate; mounting the base frame over the integrated circuit die and the package substrate; and removing the support panel from the base frame.