Dual Backside Metallization Rings Control FLI Plating Crowding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for addressing current crowding in regions with high copper density features surrounded by electrically neutral areas during electroplating in integrated circuit packaging are limited, leading to undesirable outcomes such as non-uniform plating and warpage issues.
Innovation Solution
The implementation of dual strip backside metallization using a first and second ring structure made of electrically conductive material, where the first ring is disposed within the second ring, improves electroplating uniformity, minimizes the capillary underfill keep out zone, enhances liquid thermal interface material removal, and reduces package warpage by acting as a current thief and providing structural stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If special additives are used within the plating chemistry to suppress plating in regions, then current crowding is addressed, but the solution has limited capacity and influences all regions on a package substrate panel equally which could produce undesirable outcomes
Solution Approach 1:
The patent applies local quality by introducing conductive rings at specific locations on the substrate to create localized electrical pathways. These rings are positioned in regions where current crowding occurs, providing targeted current distribution control without affecting other areas of the substrate. This allows different regions to have different electrical characteristics, enabling precise control over plating uniformity in high-density regions while maintaining normal operation in other areas.
Solution Approach 2:
The conductive rings serve as intermediary elements between the plating chemistry and the substrate regions. Instead of directly modifying the plating chemistry to affect all regions, the rings act as intermediate conductive structures that redistribute current locally. These rings mediate the electrical field distribution, creating equipotential zones that suppress current crowding at specific high-density regions without requiring global chemistry changes.
2Manufacturing precision
If high copper density features are surrounded by large areas that are electrically neutral, then current crowding occurs at these regions, but adding conductive rings increases device complexity
Solution Approach 1:
The conductive rings perform multiple functions simultaneously: they act as current redistribution pathways to address current crowding, serve as plating control structures to ensure uniform copper deposition, and function as electrical interconnect elements that can be integrated into the overall circuit design. This multi-functionality reduces the need for separate structures for each purpose, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent utilizes parameter changes by varying the electrical conductivity, geometry, and positioning of the rings to optimize their current redistribution effect. By adjusting these parameters, the rings can be designed to provide the exact level of current control needed in specific regions without requiring overly complex structures. The rings' electrical properties are tuned to match the local requirements of high-density feature regions.
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 results in improved plating uniformity, reduced warpage, and efficient underfill material management, enabling better sealing and testing conditions while maintaining manufacturing efficiency and cost-effectiveness.
Implementation Method 1
For a first level interconnect (FLI) of electroplated copper (e.g., copper contact points or bumps), there are a limited number of solutions to address current crowding at regions were high copper density features are surrounded by large areas that are electrically neutral.
Implementation Method 2
The implementation of dual strip backside metallization using a first and second ring structure made of electrically conductive material, where the first ring is disposed within the second ring, improves electroplating uniformity, minimizes the capillary underfill keep out zone, enhances liquid thermal interface material removal, and reduces package warpage by acting as a current thief and providing structural stiffness.
Data Source
AI summary
An integrated circuit assembly including a substrate having a surface including at least one area including contact points operable for connection with an integrated circuit die; and at least one ring surrounding the at least one area, the at least one ring including an electrically conductive material. A method of forming an integrated circuit assembly including forming a plurality of electrically conductive rings around a periphery of a die area of a substrate selected for attachment of at least one integrated circuit die, wherein the plurality of rings are formed one inside the other; and forming a plurality of contact points in the die area.