Below-PCB Thermal Bus Routing for IC Heat Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional chip packaging schemes face challenges in efficiently cooling IC dies located deep within a chip stack and IC devices mounted below the PCB, as they rely on inefficient heat transfer paths such as ambient air movement and poor thermal conduction through the PCB, limiting the power and reliability of these components.
Innovation Solution
A thermal bus is disposed on the backside of the PCB to route heat efficiently to a thermal management device on the front side, providing a conductive heat transfer path laterally outward of the chip package, utilizing active or passive heat transfer devices and materials like heat pipes or phase change materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If IC devices are mounted below the PCB to improve routing efficiency and reduce capacitance, then electrical performance is improved, but thermal management becomes difficult due to poor heat transfer paths
Solution Approach 1:
The patent introduces a lateral heat transfer dimension by routing the thermal bus through the PCB substrate from below to the side of the chip package, rather than relying solely on vertical heat transfer through the PCB. This dimensional change enables efficient heat evacuation from IC devices mounted below the PCB without compromising electrical performance.
Solution Approach 2:
The patent employs a thermal bus as an intermediary heat transfer component that bridges the gap between IC devices mounted below the PCB and the thermal management device on top of the chip package. This intermediary structure provides a dedicated thermal conduction path through the PCB substrate, solving the heat transfer problem while preserving the electrical benefits of below-PCB mounting.
2Temperature
If heat transfer paths are extended laterally outward of the chip package to improve cooling of bottom IC dies, then thermal management is improved, but device complexity increases
Solution Approach 1:
The PCB substrate serves multiple functions: it provides electrical interconnection, mechanical support, and acts as a thermal conduction path for the thermal bus. By making the PCB multi-functional, the patent achieves improved thermal management without adding separate structural components, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent merges the thermal bus structure with the PCB substrate, integrating the heat transfer function into the existing PCB structure. This consolidation eliminates the need for separate thermal management components and simplifies the overall device architecture while achieving effective lateral heat transfer.
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 enhances thermal regulation, allowing high-powered IC devices to be positioned directly below the chip package, improving performance and reliability by providing efficient heat conduction and temperature control without sacrificing space or reliability.
Implementation Method 1
A first conductive heat transfer path is defined between the thermal bus and the thermal management device. The first conductive heat transfer path is disposed laterally outward of the chip package.
Implementation Method 2
The thermal management device can be a thermal conductive material with or without exposed surfaces that extend into the surrounding fluid and/or solid state refrigerant.
Implementation Method 3
The thermal bus includes a phase change material disposed in a sealed cavity.
Data Source
AI summary
Disclosed herein are electronic devices that utilized a thermal bus disposed on a backside of a printed circuit board (PCB) to route heat efficiently to a thermal management device disposed on the front side of the PCB, thus enhancing thermal regulation of integrated circuit (IC) devices mounted on the backside of the PCB.