Packaging Substrate Saw Street Features for Reduced Deformation
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Solution Overview
Problem
Packaging substrates used in electronic devices tend to deform during high-pressure manufacturing processes such as overmolding, leading to warping, delamination, and electrical failures due to inadequate support and uniformity in the saw street and electrical contacts regions.
Innovation Solution
Incorporating saw street features and ground pad features with specific solder mask and metal layer configurations on the packaging substrate's downward-facing surface to provide reduced height non-uniformity and improved resistance to deformation, allowing the substrate to withstand pressure without warping, and facilitating easier fabrication without additional processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional packaging substrates are used without additional support features, then the fabrication process remains simple, but the substrate deforms during high-pressure manufacturing processes such as overmolding
Solution Approach 1:
The substrate surface is segmented into functional regions including saw street regions and electrical contact regions. Metal layers are selectively formed in these specific regions to provide localized support and deformation resistance where needed during high-pressure manufacturing processes
Solution Approach 2:
Metal layers are applied locally in saw street regions and electrical contact regions rather than uniformly across the entire substrate. This localized application provides targeted reinforcement at critical areas prone to deformation while maintaining fabrication simplicity and cost-effectiveness
2Manufacturing precision
If metal layers and solder mask layers are added to the saw street region, then deformation resistance is improved, but the manufacturing process complexity increases
Solution Approach 1:
The formation of metal layers and solder mask layers in saw street regions is merged with existing fabrication processes. The metal layers are formed using standard metal deposition techniques already employed for electrical contacts, and the solder mask is applied as part of the existing solder mask formation process, eliminating the need for separate additional manufacturing steps
Solution Approach 2:
The metal layers serve multiple functions: they provide mechanical support to prevent substrate deformation during high-pressure processes, act as electrical shields, and serve as solderable surfaces. The solder mask layers simultaneously protect the metal layers and provide soldering functionality, maximizing the utility of each added layer
Data Source
AI summary
A packaging substrate can include a first surface having a first mounting region of a first electronic module region and a second mounting region of a second electronic module region, the second electronic module region being adjacent to the first electronic module region. The packaging substrate can include a second opposing surface having a first electrical contacts region of the first electronic module region and a second electrical contacts region of the second electronic module region. A saw street region can extend between the first and second electronic module regions, and a saw street feature can be formed on the second opposing surface within at least a portion of the saw street region, the saw street feature comprising a solder mask layer over a metal layer and being spaced from the first and second electronic module regions.