3D Redistribution Layer Lines for Lower Resistance Packaging
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Solution Overview
Problem
Legacy packages with rectangular cross-section conductive lines face challenges in increasing cross-sectional area without increasing z-height or lateral area, which limits current flow due to high ohmic resistance.
Innovation Solution
Incorporating a dielectric layer with a conductive line featuring a first portion extending beyond the dielectric layer's plane and a second portion positioned between its faces, increasing the cross-sectional area without expanding the line's z-height or lateral dimensions, achieved through a plating and planarising deposition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cross-sectional area of the conductive line is increased to reduce ohmic resistance, then current flow is improved, but the z-height or lateral area of the package must be increased
Solution Approach 1:
The conductive line transitions from a conventional two-dimensional planar structure to a three-dimensional structure by extending vertically beyond the dielectric layer plane. The first portion extends above the dielectric layer while the second portion remains between the dielectric faces, creating a multi-level configuration that increases cross-sectional area without expanding the package footprint.
Solution Approach 2:
The conductive line is nested within and extending from the dielectric layer structure. The second portion is embedded between the dielectric faces while the first portion emerges from the dielectric layer, creating a nested configuration that maximizes space utilization and increases conductive cross-section within constrained dimensions.
2Reliability
If the cross-sectional area of the conductive line is increased to reduce ohmic resistance, then electrical conductivity is improved, but the lateral area of the line must be increased
Solution Approach 1:
The invention transitions from lateral expansion to vertical expansion by extending the conductive line above the dielectric layer plane. This dimensional shift allows the cross-sectional area to increase through vertical height rather than lateral width, maintaining a compact lateral footprint while improving electrical conductivity.
3Reliability
If the z-height of the conductive line is increased to increase cross-sectional area, then current flow is improved, but the package height must be increased
Solution Approach 1:
The conductive line exhibits local quality variation with different portions having different spatial configurations. The first portion extends vertically above the dielectric layer to increase cross-sectional area locally, while the second portion remains embedded between the dielectric faces, creating a differentiated structure that improves current flow without uniformly increasing package height.
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 configuration reduces ohmic resistance and enhances current flow without increasing the package's size, allowing for more efficient signal transfer while maintaining compact device dimensions.
Implementation Method 1
achieved through a plating and planarising deposition process
Implementation Method 2
achieved through a plating and planarising deposition process
Data Source
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AI summary
Embodiments herein may relate to a package with a dielectric layer having a first face and a second face opposite the first face. A conductive line of a patterned metal redistribution layer (RDL) may be coupled with the second face of the dielectric layer. The line may include a first portion with a first width and a second portion directly coupled to the first portion, the second portion having a second width. The first portion may extend beyond a plane of the second face of the dielectric layer, and the second portion may be positioned between the first face and the second face of the dielectric layer. Other embodiments may be described and/or claimed.