Pin-Based Vertical Interconnects for Thick Package Substrates
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Solution Overview
Problem
The increasing size and number of integrated circuits (ICs) on a substrate core leads to substrate warpage issues, necessitating thicker substrate cores, which in turn increases the aspect ratio of through holes, causing challenges in copper plating, reduced interconnect density, and reliability concerns due to electromigration.
Innovation Solution
The use of pre-fabricated metal pins aligned within through holes of the substrate core, filled with resin, eliminates the need for copper plating, allowing for thicker substrate cores with maintained interconnect density and electrical performance, and enables the use of alternative materials like glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the substrate core thickness is increased to provide mechanical stability and mitigate warpage, then the mechanical stability and warpage resistance are improved, but the aspect ratio of through holes increases causing copper plating challenges and reduced interconnect density
Solution Approach 1:
The patent extracts the copper plating process from the through hole fabrication sequence and replaces it with pre-fabricated metal pins. This eliminates the plating challenges associated with high aspect ratio through holes while maintaining vertical interconnect functionality in thicker substrate cores
Solution Approach 2:
Metal pins are pre-fabricated with their conductive properties before being inserted into the through holes. This preliminary preparation of conductive elements avoids the need for in-situ plating of high aspect ratio holes, resolving the manufacturing precision issue while allowing thicker substrate cores
2Strength
If the substrate core thickness is increased to support larger ICs, then the mechanical stability is improved, but the interconnect density is reduced due to the increased aspect ratio of through holes
Solution Approach 1:
The patent removes the constraint of copper plating from the through hole fabrication process. By using pre-fabricated metal pins instead of plated copper, the design is no longer limited by plating capabilities in high aspect ratio holes, allowing maintained interconnect density in thicker substrates
Solution Approach 2:
The patent changes the fabrication parameter from copper plating thickness control to metal pin insertion. This parameter change allows for consistent vertical interconnects in thicker substrate cores without the density reduction that would result from plating limitations in high aspect ratio holes
3Reliability
If copper plating is used in high aspect ratio through holes, then vertical electrical connectivity is achieved, but reliability concerns arise due to electromigration
Solution Approach 1:
The patent extracts the electromigration problem by removing the copper plating process entirely. Pre-fabricated metal pins provide the necessary vertical electrical connectivity without undergoing the plating process that generates electromigration issues, thereby improving electrical connectivity reliability
Solution Approach 2:
The patent uses robust pre-fabricated metal pins that are inserted and fixed in place, replacing the fragile plated copper structures. These pins provide reliable, durable electrical connections that are not subject to the degradation mechanisms affecting plated structures
Data Source
AI summary
A substrate is disclosed. In one embodiment, the substrate comprises a substrate core including a plurality of through holes located therethrough, a plurality of metal pins aligned in the plurality of through holes, and at least one layer deposited on at least one of top and bottom surfaces of the substrate core. In one embodiment, the plurality of metal pins are aligned with the plurality of through holes such that each of the plurality of metal pins extends at least to both the top and bottom surface of the substate core. In some embodiments, the deposited at least one layer is deposited after the plurality of metal pins have been aligned in the through holes of the substrate core.