IC-PCB Heatsink Plate Assembly for Low-Inductance RF Cooling
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Solution Overview
Problem
Existing surface-mount IC-PCB assemblies face challenges in effectively conducting heat away from high-power RFICs due to the electrical resistance and inductance of thermal vias, which can lead to reduced RF output power and increased heat-related issues, especially at high frequencies, and are costly when using ceramic packaging.
Innovation Solution
A surface-mount IC-PCB assembly featuring a heatsink plate with posts that project through a single large via hole in the PCB, providing superior thermal and electrical conductivity, minimizing inductance and resistance, and allowing for low-cost plastic packaging, while maintaining effective heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal vias are used to conduct heat away from ICs, then heat dissipation is improved, but electrical resistance and inductance increase causing RF performance degradation
Solution Approach 1:
The invention divides the thermal conduction path into multiple segments: thermal vias for vertical heat transfer through the PCB, and a heatsink plate with extended surfaces for lateral heat distribution and dissipation. This segmentation allows optimization of each segment's function while minimizing their combined negative electrical effects.
Solution Approach 2:
The invention transitions from purely vertical thermal conduction through thermal vias to a three-dimensional heat dissipation structure by adding a heatsink plate that extends in the lateral dimension. This dimensional expansion provides additional thermal conduction pathways without requiring proportionally more thermal vias, thereby reducing the cumulative electrical resistance and inductance.
2Reliability
If ceramic packaging is used for high-power RFICs, then heat dissipation and RF performance are improved, but manufacturing cost increases significantly
Solution Approach 1:
The invention replaces expensive ceramic packaging with a cost-effective alternative using standard plastic IC packages combined with an external heatsink plate. This substitution maintains the necessary thermal and RF performance while dramatically reducing manufacturing costs, making the solution viable for commercial applications.
Solution Approach 2:
The heatsink plate acts as an intermediary component that bridges the plastic IC package and the PCB thermal vias. It provides the necessary thermal conduction pathway and mechanical support that would otherwise require expensive ceramic packaging, while allowing the use of cheaper plastic packages.
3Loss of energy
If multiple thermal vias are used to reduce electrical resistance, then heat conduction is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The invention merges the functions of multiple thermal vias into a single integrated heatsink plate structure. The plate consolidates the thermal conduction pathways, providing equivalent or superior heat dissipation with fewer via holes, thereby reducing manufacturing complexity and the cumulative electrical resistance and inductance.
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
The solution enables efficient heat removal from ICs, doubling RF output power across a wide frequency range and reducing manufacturing costs by using a single-post or multi-post heatsink design, which is simpler and less expensive than ceramic packaging solutions.
Implementation Method 1
The heatsink plate has posts that project from a mounting surface of the heatsink plate, and when the heatsink plate is mounted to the heatsink plate receiving pad, each post extends from the second side of the PCB, through a matching hole in the PCB, and to an associated thermal pad located on the first side of the PCB
Data Source
AI summary
An integrated circuit/printed circuit board (IC-PCB) assembly comprises a PCB and a heatsink plate. The PCB has a first side including a first patterned conductive layer with one or more thermal pads onto which one or more heat slugs of one or more ICs mount, and a second, opposing side including a second patterned conductive layer with a heatsink plate receiving pad onto which the heatsink plate mounts. The heatsink plate has one or more posts that project from a mounting surface of the heatsink plate, and when the heatsink plate is mounted to the heatsink plate receiving pad, each post extends from the second side of the PCB, through a matching hole in the PCB, and to an associated thermal pad located on the first side of the PCB.