Trapezoidal Post Interconnects for Reliable Package Joints
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Solution Overview
Problem
There is a need for packages with robust and reliable joints between components, particularly between integrated devices and substrates, to enhance performance and reduce the likelihood of delamination and electrical path failures.
Innovation Solution
The use of post interconnects with a trapezoid profile cross section, which are coupled with solder interconnects, helps reduce stress on dielectric layers and provides a more reliable electrical path by varying the width of the interconnects, allowing for a stronger and more stable joint between the integrated device and the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If post interconnects with uniform cross section are used, then the manufacturing process is simpler, but the stress distribution on dielectric layers is poor and delamination risk increases
Solution Approach 1:
The post interconnects are designed with a trapezoidal cross-section where the width varies along the height, being wider at the top and narrower at the bottom. This asymmetric geometry optimizes stress distribution across the dielectric layers while maintaining manufacturability through standard plating processes.
Solution Approach 2:
Different sections of the post interconnect have different widths to address local stress requirements. The wider top section provides better mechanical support and stress distribution at the integrated device interface, while the narrower bottom section reduces stress concentration in the substrate region.
2Reliability
If post interconnects with varying width are used, then stress on dielectric layers is reduced and delamination is prevented, but the manufacturing precision requirements increase
Solution Approach 1:
The cross-sectional width parameter of the post interconnects is varied along the height to optimize stress distribution. This parameter change is achieved through controlled plating processes that can produce the desired trapezoidal profile with acceptable precision for reliable stress management.
3Strength
If larger post interconnect width is used, then joint strength between integrated device and substrate is improved, but the area occupied on substrate increases
Solution Approach 1:
The trapezoidal cross-section creates an asymmetric width distribution where the top width (at the integrated device interface) is larger than the bottom width (at the substrate interface). This provides stronger joints where needed while minimizing substrate area occupation.
Solution Approach 2:
The post interconnects have localized width variations that concentrate mechanical strength at the integrated device interface where it is most needed, while reducing the width at the substrate level to minimize area occupation and stress concentration.
Data Source
AI summary
A package comprising an integrated device and a substrate coupled to the integrated device. The substrate comprises at least one dielectric layer and a plurality of interconnects. The plurality of interconnects include a plurality of post interconnects. The plurality of post interconnects include a post interconnect comprising a profile cross section that includes a trapezoid shape.