Frontside Thermal Contacts for Microelectronic Packages
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Solution Overview
Problem
High performance semiconductor dies generate excess heat, and existing microelectronic packages with dielectric encapsulants hinder efficient heat dissipation due to low thermal conductivity, necessitating improved thermal management solutions.
Innovation Solution
The method involves fabricating microelectronic packages with frontside thermal contacts by forming a thermally-conductive base layer and primary heat sink bodies over the semiconductor die, which are then exposed through the package's frontside for direct heat dissipation, enhancing thermal conductivity and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric encapsulant is used to encapsulate the semiconductor die, then the die is protected and encapsulated within the package, but heat dissipation from the semiconductor die is reduced due to the low thermal conductivity of the dielectric material
Solution Approach 1:
The package is segmented into distinct thermal management zones: a frontside thermal contact region with high thermal conductivity materials for heat extraction, and a dielectric encapsulant region for protection. This segmentation allows simultaneous achievement of die protection and efficient heat dissipation by separating these conflicting functions into different spatial regions.
Solution Approach 2:
Different regions of the package are assigned different thermal conductivities tailored to their specific functions. The frontside region contains high thermal conductivity materials (metal traces, thermal contact) for heat dissipation, while the dielectric encapsulant provides protection. This local differentiation of material properties resolves the contradiction between protection and heat dissipation.
2Temperature
If a copper slug is attached to package backside with direct contact to the die, then heat dissipation is improved, but the fabrication process becomes more complex requiring die exposure through the backside
Solution Approach 1:
Instead of accessing the die through the backside of the package, the thermal contact is inverted to access the die through the frontside. The metal trace and thermal contact are formed on the frontside of the encapsulant, allowing direct thermal coupling to the die's front surface without requiring backside die exposure, thus simplifying fabrication.
Solution Approach 2:
A metal trace embedded within the dielectric encapsulant serves as an intermediary thermal conduction path. This trace provides a thermal bridge from the frontside thermal contact to the semiconductor die, enabling heat dissipation without requiring direct backside contact or complex die exposure processes.
3Ease of manufacture
If a thin layer of encapsulant is provided between the die and copper slug, then the RCP package fabrication process is eased, but the thermal conductivity of the heat dissipation path is reduced
Solution Approach 1:
The thermal contact interface is extracted from the backside assembly process and relocated to the frontside of the encapsulant. This allows the encapsulant to maintain its full protective thickness while the thermal contact is established separately at the frontside, eliminating the trade-off between encapsulant thickness and thermal conductivity.
Solution Approach 2:
The mechanical assembly process of attaching a copper slug to the backside is replaced with a deposition and patterning process that forms metal traces and thermal contacts directly within the frontside of the encapsulant during fabrication, simplifying the overall manufacturing process while maintaining thermal performance.
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 provides a highly efficient thermal conduction path from the semiconductor die to the package's exterior, significantly improving heat dissipation and thermal performance of microelectronic packages.
Implementation Method 1
provides a highly efficient thermal conduction path from the semiconductor die to the package's exterior
Data Source
AI summary
Microelectronic packages and methods for fabricating microelectronic packages are provided. In one embodiment, the method includes forming one or more redistribution layers over an encapsulated die having a frontside bond pad area and a frontside passivated non-bond pad area. The redistribution layers are formed to have a frontside opening over the non-bond pad area of the encapsulated die. A primary heat sink body is provided in the frontside opening and thermally coupled to the encapsulated die. A contact array is formed over the redistribution layers and is electrically coupled to a plurality bond pads located on the frontside bond pad area of the encapsulated die.