Multi-Architecture SLI Package Layout for Warpage Defects
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Solution Overview
Problem
High temperature warpage of finished electronic packages leads to increased defects in second level interconnects (SLIs) during surface mount technology (SMT) assembly, negatively impacting yield.
Innovation Solution
Implementing multiple interconnect architectures with varying diameters, material compositions, and structures across different regions of the package substrate to mitigate warpage-induced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a weighted reflow process is used to flatten the package, then the effect of warpage is decreased, but the process becomes cost prohibitive and adds burden to assembly processes
Solution Approach 1:
The patent applies local quality by using different interconnect types (solder balls, solder bumps, eutectic interconnects) in different regions of the package substrate. Specifically, eutectic interconnects are placed in corner regions where warpage effects are most severe, while other regions use standard solder balls or bumps. This localized approach addresses warpage in critical areas without requiring global process modifications like weighted reflow, thereby maintaining manufacturing precision while avoiding increased process complexity and cost.
2Manufacturing precision
If the package substrate core thickness is increased, then warpage effect is reduced, but the overall package thickness increases and substrate cost increases
Solution Approach 1:
Instead of uniformly increasing substrate core thickness, the patent uses local quality by implementing different interconnect architectures in different regions. The eutectic interconnects in corner regions provide localized warpage compensation without requiring increased overall substrate thickness. This maintains the package's Z-height while addressing warpage in specific high-stress areas.
Solution Approach 2:
The patent employs composite materials by using eutectic interconnects that combine specific material compositions (e.g., tin-lead or tin-silver-lead alloys with controlled melting ranges) to create interconnects with tailored mechanical and thermal properties. These composite interconnect structures provide warpage compensation through their material characteristics rather than relying on increased substrate thickness.
3Manufacturing precision
If the package substrate core thickness is increased, then warpage effect is reduced, but electrical and thermal performance are negatively impacted
Solution Approach 1:
The patent maintains electrical and thermal performance by using local quality - placing eutectic interconnects only in corner regions where warpage is most severe, while keeping the substrate core thickness optimized for electrical and thermal performance in the main body. This localized approach provides warpage control without compromising the electrical and thermal pathways that run through the substrate core.
Solution Approach 2:
The patent applies segmentation by dividing the interconnect structure into different types (solder balls, solder bumps, eutectic interconnects) placed in different regions. This segmentation allows the substrate core to maintain its optimal thickness for electrical and thermal performance while the segmented eutectic interconnects in corner regions provide localized warpage compensation.
4Ease of manufacture
If uniform interconnect architecture is used, then manufacturing is simpler, but warpage-induced defects increase
Solution Approach 1:
The patent resolves this contradiction by applying local quality - using different interconnect architectures (solder balls, solder bumps, eutectic interconnects) in different regions of the package substrate. Eutectic interconnects with controlled melting ranges are placed in corner regions where warpage causes most defects, while other regions use standard interconnects. This maintains relative manufacturing simplicity while significantly reducing warpage-induced defects like bridging and non-contact opens.
Data Source
AI summary
Embodiments include an apparatus with interconnects that have different structures. In an embodiment, the apparatus comprises a substrate and a first interconnect on the substrate, a second interconnect on the substrate, and a third interconnect on the substrate. In an embodiment, the first interconnect, the second interconnect, and the third interconnect are all different from each other.