Protruding Copper Termination Structures for Interposer Bonding
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Solution Overview
Problem
Current interposer termination technologies face challenges in achieving reliable, cost-effective, and high-yield connections at tighter pitches due to limited contact area and susceptibility to electrical open failures, with additional processing steps and increased costs associated with copper pillars and solderable materials.
Innovation Solution
The solution involves a multilayer electronic support structure with a copper routing layer partially embedded in a dielectric material, where the outer copper features protrude beyond the dielectric, coated with Organic Solderability Preservative (OSP), allowing for enhanced solder wetting and bonding on both top and side surfaces, thereby improving anchoring and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If copper via posts are embedded in dielectric and thinned to be flush with the surface, then planarity is improved, but the contact area for solder bonding is limited to the cross-sectional area
Solution Approach 1:
The invention transitions from a two-dimensional contact interface (flush surface only) to a three-dimensional contact interface by allowing copper features to protrude from the dielectric surface. This dimensional change enables solder to contact both the top surface and the exposed side walls of the copper features, significantly increasing the effective bonding area while maintaining planarity where needed.
2Area of stationary object
If copper pillars are used with protruding structures, then contact area is increased, but manufacturing complexity and processing steps increase
Solution Approach 1:
The invention merges the copper routing layer with the termination structure by allowing the copper features to naturally protrude from the dielectric surface during the lamination process. This eliminates the need for separate copper pillar fabrication steps, reducing manufacturing complexity while maintaining the beneficial increased contact area.
3Length of moving object
If tighter pitch is used for solder bumps, then miniaturization is achieved, but the risk of shorting between nearby connections increases
Solution Approach 1:
By enabling solder to bond to both the top surface and exposed side walls of protruding copper features, the invention creates a more robust connection that can better withstand the challenges of tighter pitches. The increased contact area provides greater bonding strength and better electrical connection, reducing the risk of opens and shorts even when connections are closer together.
4Ease of manufacture
If all contacts are in a single plane, then manufacturing is simplified, but susceptibility to disconnected contacts and electrical open failures increases
Solution Approach 1:
The invention moves the contact interface from a single plane to a three-dimensional structure where solder can contact both the top surface and exposed side walls of copper features. This multi-level contact approach creates redundant bonding paths, reducing the risk of electrical open failures while remaining compatible with existing manufacturing processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables stronger, reliable anchoring of IC chips with reduced manufacturing costs and increased yield by providing a larger contact area for solder bonding, minimizing the risk of electrical failures and thickness issues at tighter pitches.
Implementation Method 1
coated with Organic Solderability Preservative (OSP), allowing for enhanced solder wetting and bonding on both top and side surfaces
Data Source
AI summary
An electronic support structure comprising one or more layers of copper features such as copper routing layers, laminated within a dielectric material comprising continuous glass fibers in a polymer matrix wherein pairs of adjacent layers of copper features are coupled by a via layer, and where terminations on at least one side of the electronic support structure comprise a modified bond-on-trace attachment sites comprising selectively exposed top and partial side surfaces of copper features in an outer layer of copper features for conductive coupling solder.