Embedded RDL Heat Spreader for Miniature RF IC Packaging
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Solution Overview
Problem
The miniaturization of RF integrated circuits in mobile devices leads to challenges in heat transfer and reduced radio frequency performance due to packaging limitations, which affects the efficiency of heat removal and electromagnetic coupling.
Innovation Solution
An integrated circuit package with an embedded heat spreader in a redistribution layer (RDL) coupled to the IC die, facilitating efficient heat transfer and reducing electromagnetic coupling, while enabling robust RF performance through millimeter wave frequencies in a low-profile, low-cost, surface mountable package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If IC package size is decreased to meet miniaturization demands, then device size is reduced, but heat removal efficiency deteriorates
Solution Approach 1:
The patent introduces a vertical heat extraction path by embedding a heat spreader within the RDL structure that extends from the die interface upward through the package. This three-dimensional heat management approach allows heat to be removed in the vertical dimension rather than relying solely on lateral spreading at the package base, enabling effective thermal management in miniaturized packages.
Solution Approach 2:
The heat spreader is embedded within the RDL dielectric layer, creating a nested structure where the heat spreader is contained inside the RDL volume. This nested configuration allows the heat spreader to be integrated into the existing package structure without increasing overall package size, while still providing dedicated heat removal functionality.
2Area of stationary object
If IC package size is decreased, then device footprint is reduced, but RF performance deteriorates due to electromagnetic coupling
Solution Approach 1:
The RDL dielectric layer is selectively removed only in the region directly above the heat spreader to expose it for thermal contact, while other regions of the RDL maintain their insulating properties. This localized modification allows heat extraction without compromising the electromagnetic shielding and signal integrity provided by the remaining RDL structure, thus preserving RF performance in the miniaturized package.
3Temperature
If heat spreader is embedded in RDL, then heat transfer efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The heat spreader is embedded within the RDL dielectric layer during the RDL formation process itself, rather than being added as a separate post-processing step. The dielectric layer is deposited, then selectively removed to expose the heat spreader, allowing thermal contact to be established during the standard RDL fabrication sequence. This preliminary integration reduces overall manufacturing complexity compared to adding heat extraction features after package assembly.
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 embedded heat spreader enhances thermal management and RF performance, mitigating the detrimental effects of packaging on heat removal and electromagnetic interference, thereby improving the overall performance of RF circuits in miniature packages.
Implementation Method 1
an embedded heat spreader within a dielectric layer of a RDL coupled to an IC die... The embedded heat spreader provides efficient heat transfer
Data Source
AI summary
An integrated circuit (IC) package with an embedded heat spreader in a redistribution layer (RDL) is provided. IC packaging facilitates a high density package for ICs, including monolithic microwave integrated circuits (MMICs). However, IC packaging may result in reduced heat removal from an IC, decreasing radio frequency (RF) circuit performance. In an exemplary aspect, an IC package is provided which incorporates an embedded heat spreader within a dielectric layer of an RDL coupled to an IC die. The embedded heat spreader provides efficient heat transfer, robust RF performance, and operation through millimeter wave (mmW) frequencies, all in a miniature low-cost, low-profile surface mountable (SM) package.