Package Substrate Openings for Signal Integrity
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Solution Overview
Problem
In high data rate applications, semiconductor device design faces challenges in impedance matching and trace insertion loss due to the increasing demand for reduced dimensions and improved efficiency, where narrow conductive traces result in significant resistive transmission loss and impedance mismatch.
Innovation Solution
The introduction of openings in reference layers above or below conductive traces on package substrates enhances the electric and magnetic fields, allowing for wider conductive traces while maintaining target impedance values, thereby reducing insertion loss and improving signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If narrow conductive traces are used to reduce device dimensions, then the area of the substrate is reduced, but the insertion loss increases significantly
Solution Approach 1:
The patent introduces openings in the reference layer above or below the conductive traces, utilizing the vertical dimension (Z-axis) to modify the electromagnetic field distribution. This dimensional change allows the electric and magnetic fields to be enhanced in the vertical direction, compensating for the reduced trace width and thereby reducing insertion loss while maintaining compact device dimensions.
Solution Approach 2:
The patent modifies the physical parameters of the substrate structure by introducing openings with specific dimensions, positions, and patterns in the reference layer. These parameter changes alter the electromagnetic field distribution and impedance characteristics, enabling wider effective trace width equivalent behavior in narrow traces, thus reducing resistive transmission loss.
2Productivity
If narrow conductive traces are used to improve efficiency, then the substrate area is reduced, but the impedance matching becomes more challenging
Solution Approach 1:
By introducing openings in the reference layer, the patent utilizes the vertical dimension to control impedance characteristics. The openings modify the distributed capacitance and inductance along the trace, enabling impedance matching to be achieved with narrower traces, thus improving efficiency while maintaining manufacturability.
Solution Approach 2:
The patent applies local quality changes by strategically positioning openings at specific locations relative to the conductive traces (above or below), with varying sizes and patterns. This localized modification of the reference layer creates regions with different electromagnetic properties, enabling precise impedance control and matching in high data rate applications.
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 reduces insertion loss by up to 70% at DC and 25-35% at high frequencies, enabling better signal integrity and impedance matching for high data rate signals.
Implementation Method 1
The introduction of openings in reference layers above or below conductive traces on package substrates enhances the electric and magnetic fields
Implementation Method 2
The introduction of openings in reference layers above or below conductive traces on package substrates enhances the electric and magnetic fields
Data Source
AI summary
A substrate includes: (1) a first patterned conductive layer, the first patterned conductive layer including a pair of first transmission lines adjacent to each other; and (2) a first reference layer above the pair of first transmission lines, the first reference layer defining an opening, wherein the pair of first transmission lines are exposed to the opening.