IC Package Hood Assembly Using Microsprings for Thermal Stress Relief
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Solution Overview
Problem
Existing packaging solutions for integrated electronic devices, particularly those with encapsulation hoods, face issues with defects such as cracks and delamination due to stress accumulation from differing expansion coefficients of components, which can lead to malfunction.
Innovation Solution
A package structure that uses microsprings to electrically couple the encapsulation hood's conductive path to the support substrate's conductive zones, along with an insulating auxiliary attachment, to absorb expansion stresses and minimize defect risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spots of electrically conductive glue or solder pads are used to fasten the encapsulation hood to the support substrate, then electrical conduction is achieved between the conductive zones, but stress accumulation from different expansion coefficients causes cracks and delamination
Solution Approach 1:
The patent changes the mechanical parameter of the fastening element from rigid (glue spots or solder pads) to elastic (springs). The springs can deform elastically under stress, accommodating the different thermal expansion coefficients of the encapsulation hood and support substrate while maintaining electrical conduction through the conductive path integrated into the spring structure.
Solution Approach 2:
The patent employs springs as flexible fastening elements that can deform to absorb stress. These springs act as flexible connectors that maintain electrical contact while accommodating dimensional changes due to thermal expansion, preventing the cracks and delamination that occur with rigid fastening methods.
2Reliability
If rigid electrically conductive fastening regions are used to ensure stable electrical connection, then electrical conduction is reliable, but the package becomes susceptible to cracks and delamination from thermal stress
Solution Approach 1:
The patent transforms the fastening element from a rigid structure to an elastic spring structure. This parameter change allows the fastening element to dynamically adjust to stress conditions while maintaining electrical conduction, thereby preventing stress-induced defects while preserving connection reliability.
Solution Approach 2:
The springs serve as pre-configured stress-absorbing elements that cushion against thermal expansion mismatches before damage can occur. The elastic deformation capability of the springs provides a buffer zone that protects the package from stress-induced cracks and delamination.
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 proposed solution effectively reduces the risk of defects like cracks and delamination, ensuring reliable electrical contact and minimizing the likelihood of package malfunction.
Implementation Method 1
the fastening device includes at least two springs, for example microsprings, respectively electrically coupling the two ends of the electrically conductive path to two corresponding electrically conductive zones of the support substrate
Data Source
AI summary
An encapsulation hood is fastened onto electrically conductive zones of a support substrate using springs. Each spring has a region in contact with an electrically conductive path contained in the encapsulation hood and another region in contact with a corresponding one of the electrically conductive zones. The fastening of the part of the encapsulation hood onto the support substrate compresses the springs and further utilizes a bead of insulating glue located between the compressed springs.