RDL Contact Pad Wing Design for Thermal Stress Relief
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Solution Overview
Problem
Semiconductor package assemblies face thermal electrical issues such as heat dissipation, cross talk, signal propagation delay, and electromagnetic interference due to increased input/output connections, affecting reliability and quality, particularly in miniaturized, multi-functional devices.
Innovation Solution
The design incorporates a redistribution layer (RDL) structure with symmetrical and extended wing portions in RDL contact pads, optimized for stress relief and electrical connectivity, which differs in orientation between the die region and molding compound region to address thermal expansion mismatches and improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of input/output connections is increased to support multi-functional chips, then the functionality and pin connection capability are improved, but thermal electrical problems such as heat dissipation, cross talk, signal propagation delay, and electromagnetic interference worsen
Solution Approach 1:
The RDL contact pad is segmented into multiple functional regions: a symmetrical portion for electrical connection and signal transmission, and extended wing portions for stress distribution and thermal management. This segmentation allows each region to optimize its function independently, reducing thermal electrical problems while maintaining multi-functional capability
Solution Approach 2:
The contact pad design employs asymmetry by extending wings in specific directions away from the semiconductor die, creating an asymmetric geometry that optimizes stress distribution patterns and thermal pathways. The asymmetric extension allows better heat dissipation and reduced electromagnetic interference compared to symmetric designs
2Ease of manufacture
If the RDL contact pad uses a symmetrical design, then the manufacturing simplicity is improved, but the ability to relieve stress and manage thermal expansion mismatches worsens
Solution Approach 1:
The contact pad design applies local quality by having different geometric characteristics in different regions: the central symmetrical portion maintains manufacturing simplicity, while the extended wing portions provide localized stress relief and thermal management functions. This localized differentiation resolves the contradiction between manufacturing ease and stress relief capability
3Volume of moving object
If the semiconductor package is miniaturized, then the device size is reduced, but the thermal electrical problems and reliability issues worsen
Solution Approach 1:
The extended wing portions of the contact pad extend in the planar dimension away from the die, utilizing available package area efficiently without increasing vertical height. This dimensional approach allows better thermal management and stress distribution within the constrained miniaturized package volume
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 enhances the reliability of semiconductor package assemblies by effectively managing thermal stress and electrical connectivity, reducing the risk of cracks and improving the overall performance of miniaturized, multi-functional devices.
Implementation Method 1
The extended wing portion may overlap a boundary of the symmetrical portion
Implementation Method 2
The RDL structure comprises a conductive trace and an RDL contact pad
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
The invention provides a semiconductor package assembly. The semiconductor package assembly includes a redistribution layer (RDL) structure. The RDL structure includes a conductive trace (216). A redistribution layer (RDL) contact pad (218) is electrically coupled to the conductive trace. The RDL contact pad is composed of a symmetrical portion and an extended wing portion connected to the symmetrical portion. The extended wing portion overlaps at least one-half of a boundary of the symmetrical portion when observed from a plan view.