Package on Package Configuration with Mixed Design Rule Redistribution Circuitry
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Solution Overview
Problem
Prior art package on package configurations are limited by the use of a single redistribution circuitry design rule, which restricts the application of multiple redistribution circuitries fabricated according to different design rules.
Innovation Solution
A package on package configuration is developed where a first IC package with top metal pads and copper pillars is fabricated according to IC design rules, and a second IC package with bottom metal pads is stacked on top, with copper pillars electrically coupling the two packages, allowing for multiple redistribution circuitries fabricated according to different design rules, including PCB and IC design rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single redistribution circuitry design rule is used, then manufacturing simplicity is maintained, but design flexibility and compatibility are restricted
Solution Approach 1:
The patent divides the redistribution circuitry into multiple segments with different design rules. Specifically, it implements a first redistribution circuitry layer following IC design rules and a second redistribution circuitry layer following PCB design rules, allowing each layer to be optimized independently for its specific function while maintaining overall system integration
Solution Approach 2:
The patent applies different design rule qualities to different regions/layers of the redistribution circuitry. The first redistribution circuitry layer uses IC-design-rule-based specifications for high-density interconnect requirements, while the second layer uses PCB-design-rule-based specifications for lower-density applications, ensuring each region has the appropriate design characteristics for its functional requirements
2Adaptability or versatility
If multiple redistribution circuitries with different design rules are implemented, then design flexibility is enhanced, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into distinct stages corresponding to different design rules. The process fabricates IC-design-rule-based circuitry first, then transitions to PCB-design-rule-based circuitry fabrication, allowing specialized manufacturing techniques to be applied to each segment according to its specific requirements
Solution Approach 2:
The patent changes key manufacturing parameters between different redistribution circuitry layers. It transitions from IC-design-rule parameters (finer line widths, smaller features) to PCB-design-rule parameters (larger features, different trace geometries), enabling each layer to be manufactured with optimized parameters for its specific design rule set
3Reliability
If copper pillars are used for electrical coupling, then electrical connection reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent performs preliminary actions to ensure accurate copper pillar placement before final assembly. It pre-configures the copper pillars on the first substrate according to IC design rules with precise positioning, and pre-positions the second substrate with corresponding pad structures, ensuring alignment readiness before the actual coupling process
Solution Approach 2:
The patent applies different precision requirements to different elements. The copper pillars require high precision placement according to IC design rules, while the surrounding redistribution circuitry and larger PCB-design-rule features have relaxed precision requirements, allowing the system to achieve high reliability connections without requiring ultra-precision throughout the entire structure
Data Source
AI summary
A first integrated circuit (IC) package has a package substrate on bottom. The package substrate comprises a bottom redistribution circuitry configured according to printed circuit board (PCB) design rule and a top redistribution circuitry configured according to integrated circuit (IC) design rule. The first IC package has a plurality of top metal pads and a plurality of copper pillars configured on a top side according to IC design rule. A second IC package has a plurality of bottom metal pads configured according to IC design rule configured on a top side of the first IC package. The first IC package electrically couples to the second IC package through the plurality of copper pillars.