Reduced Capacitance Land Pad for LGA Signal Integrity
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Solution Overview
Problem
As semiconductor device dimensions shrink, the capacitance between land pads and parallel conductive planes increases, leading to significant energy losses and signal loss, particularly in high-frequency interconnections, which existing technologies have not adequately addressed.
Innovation Solution
A reduced capacitance land pad design is implemented, featuring a conductive area less than the contact area with non-conductive voids, which reduces the overlapping conductive area with the parallel ground plane, thereby decreasing capacitance without altering the device structure or fabrication process, and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If semiconductor device dimensions are reduced to increase processing capability, then device performance is improved, but capacitance between land pads and parallel conductive planes increases causing significant energy losses and signal loss
Solution Approach 1:
The land pad design incorporates non-conductive voids at specific locations where capacitance to the ground plane causes the most harm. By strategically placing voids in regions of highest capacitive coupling, the patent locally reduces capacitance to minimize energy losses while preserving the overall conductive area needed for electrical contact and signal transmission.
Solution Approach 2:
The land pad structure incorporates voids or holes throughout its conductive area, creating a porous configuration. This porous design reduces the overlapping conductive area between the land pad and the parallel ground plane, thereby decreasing parasitic capacitance and associated energy losses while maintaining sufficient electrical contact for device functionality.
2Loss of energy
If the conductive area of the land pad is reduced to decrease capacitance, then energy losses are reduced, but the contact area for LGA connections is compromised
Solution Approach 1:
The patent applies local quality by differentiating regions within the land pad: conductive areas maintain full contact area for LGA connections, while non-conductive voids are strategically positioned in regions where capacitance reduction is most critical. This allows the land pad to simultaneously provide adequate contact area and reduced capacitance.
Solution Approach 2:
The land pad is segmented into distinct conductive and non-conductive regions. The conductive portions maintain the necessary contact area for electrical connections, while the non-conductive voids are distributed to reduce overall capacitance. This segmentation allows independent optimization of contact area and capacitance reduction.
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 design effectively reduces signal loss and allows for greater tolerance in LGA contact positioning, maintaining structural integrity and reducing energy losses without requiring additional materials or changes to the fabrication process.
Implementation Method 1
the capacitance between land pads and parallel conductive planes increases
Implementation Method 2
non-conductive voids, which reduces the overlapping conductive area with the parallel ground plane
Data Source
AI summary
A land grid array (LGA) land pad having reduced capacitance is disclosed. The conductive portion of a land pad that overlaps a parallel ground plane within the substrate is reduced by one or more non-conductive voids though the thickness of the conductive portion of the land pad. The voids may allow the contact area of the land pad, as defined by the perimeter of the land pad, to remain the same while reducing the conductive portion that overlaps the parallel ground plane. Capacitance between the land pad and the parallel ground plane is reduced by an amount proportional to the reduction in overlapping conductive area.