Staggered Via Arrangement in Semiconductor Chip Packages
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Solution Overview
Problem
Conventional semiconductor chip packages face challenges in efficiently arranging vias and ball pads due to finer ball pad pitches, leading to increased manufacturing costs and potential electrical performance issues due to longer conductive traces and reduced space for plating traces.
Innovation Solution
The semiconductor chip package design features staggered vias and ball pads arranged in offset rows, allowing for more flexible finger placement and maximizing space for plating traces, which reduces manufacturing costs and improves electrical performance by minimizing conductive trace lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If vias are placed close to ball pads to satisfy finer ball pad pitch requirements, then space utilization improves, but via-to-finger distance becomes too short violating manufacturing constraints
Solution Approach 1:
The patent transitions from a conventional aligned via arrangement to a staggered via arrangement where vias in adjacent rows are offset from each other. This dimensional reorganization allows vias to be positioned closer to ball pads while maintaining adequate distance from fingers, effectively utilizing space without violating manufacturing constraints.
Solution Approach 2:
The patent introduces asymmetric via placement where vias in different rows are offset by different amounts and in different directions. This asymmetric arrangement optimizes the distance relationships between vias, ball pads, and fingers simultaneously, resolving the conflict between space utilization and manufacturing constraints.
2Manufacturing precision
If vias are shifted away from ball pads to maintain via-to-finger distance, then manufacturing constraints are satisfied, but conductive trace length increases degrading electrical performance
Solution Approach 1:
By staggering vias in adjacent rows, the patent creates a three-dimensional optimization pattern that reduces the horizontal distance between vias and ball pads while maintaining vertical spacing from fingers. This dimensional approach shortens conductive traces without compromising manufacturing constraints.
Solution Approach 2:
The staggered via arrangement allows different local regions to have optimized via-to-ball pad distances. Each via can be positioned optimally relative to its corresponding ball pad and adjacent fingers, improving electrical performance locally while satisfying global manufacturing constraints.
Data Source
AI summary
A semiconductor chip package is disclosed. The semiconductor chip package comprises a package substrate having a bottom surface. At least four adjacent ball pads are on the bottom surface, arranged in a first two-row array along a first direction and a second direction. At least four vias are drilled through the package substrate, arranged in a second two-row array, wherein each of the vias in a row of the second two-row array is offset by a first distance along the first direction and a second distance along the second direction from the connecting ball pads in a row of the first two-row array, and each of the vias in the other adjacent row of the second two-row array is offset by the first distance along an opposite direction to the first direction and the second distance along the second direction from the connecting ball pads in the other adjacent row of the first two-row array.