Stacking Conductive Structure Surface Roughness Control
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Solution Overview
Problem
High surface roughness of conductors in semiconductor device packages leads to increased insertion loss due to skin effect, particularly in high frequency signal transmission.
Innovation Solution
A semiconductor device package with a stacking conductive structure comprising multiple conductive layers on a dielectric layer, where the surface roughness of each layer is progressively reduced, with the grain size of subsequent layers being smaller or equal to the previous layer, thereby smoothing the surface and shortening the current transmission path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single conductive layer is used, then the structure is simple, but the surface roughness is high causing severe insertion loss
Solution Approach 1:
The conductive layer is segmented into multiple stacked conductive layers (first conductive layer, second conductive layer, third conductive layer) with progressively decreasing surface roughness. This segmentation allows each layer to contribute to signal transmission while the cumulative effect reduces overall surface roughness and insertion loss, particularly for high frequency signals affected by skin effect.
Solution Approach 2:
The solution transitions from a single-plane conductive structure to a multi-layer stacked structure in the vertical dimension. By adding the z-dimension with multiple conductive layers at different heights, the patent achieves reduced surface roughness and improved signal transmission without significantly increasing horizontal footprint.
2Loss of energy
If multiple conductive layers are stacked to reduce surface roughness, then insertion loss is reduced, but the device complexity increases
Solution Approach 1:
Each conductive layer is designed with specific local qualities - the first conductive layer has higher roughness for mechanical stability, while subsequent layers have progressively lower roughness for optimized signal transmission. This local differentiation of surface properties allows the structure to simultaneously achieve mechanical robustness and low insertion loss.
Solution Approach 2:
The patent systematically changes the surface roughness parameter across multiple conductive layers, with each subsequent layer having lower surface roughness than the previous layer. This parameter progression (Rz1 > Rz2 > Rz3) optimizes the balance between mechanical stability and electrical performance, reducing insertion loss while controlling complexity through gradual parameter transitions.
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 significantly alleviates insertion loss by reducing surface roughness and improving antenna performance in high frequency signal transmission.
Implementation Method 1
At high frequency signal transmission such as microwave or millimeter wave signal transmission, the current tends to flow in a transmission path adjacent to the perimeter of the conductor, which is known as skin effect. As the surface roughness of the conductor increases, the transmission path is increased accordingly. As a result, the insertion loss is severe.
Data Source
AI summary
A semiconductor device package includes a dielectric layer and a stacking conductive structure. The dielectric layer includes a first surface. The stacking conductive structure is disposed on the first surface of the dielectric layer. The stacking conductive structure includes a first conductive layer disposed on the first surface of the dielectric layer, and a second conductive layer stacked on the first conductive layer. A first surface roughness of the first surface of the dielectric layer is larger than a second surface roughness of a top surface of the first conductive layer, and the second surface roughness of the top surface of the first conductive layer is larger than a third surface roughness of a top surface of the second conductive layer.