Package on Packaging Structure with Heatspreader for Thermal Dissipation
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Solution Overview
Problem
Package on Package (PoP) integrated circuit packaging techniques face inefficiencies in thermal dissipation and thermal stress due to thermal expansion mismatch between components, leading to warpage and thermal dissipation inefficiency as die power increases.
Innovation Solution
Incorporating an interposer or heatspreader with thermally conductive through vias and thermal interface materials to provide a robust thermal conduction path and mechanical stiffness, reducing thermal stress and warpage by aligning thermal and mechanical properties between the top and bottom packages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If die power is increased to achieve higher density electronics, then productivity is improved, but thermal dissipation efficiency deteriorates and thermal stress increases
Solution Approach 1:
A heatspreader layer is introduced as an intermediary component between the bottom package and top package. This heatspreader has a thermal conductivity of at least 100 W/m-K and includes through-vias that extend through the bottom package, creating an intermediate thermal management layer that facilitates heat dissipation without directly increasing die power.
Solution Approach 2:
The patent employs composite material structures including the heatspreader layer combined with thermally conductive underfill materials and through-via structures. This composite approach creates a multi-layer thermal management system where each layer contributes specific thermal properties to achieve overall improved thermal dissipation efficiency.
2Productivity
If die power is increased to achieve higher density electronics, then productivity is improved, but thermal stress and warpage increase due to thermal expansion mismatch
Solution Approach 1:
The heatspreader layer acts as a mechanical intermediary that compensates for thermal expansion mismatch between the bottom and top packages. This intermediate layer with controlled thermal expansion properties reduces the stress transfer between packages, thereby minimizing warpage while maintaining the high-density electronics configuration.
Solution Approach 2:
The patent modifies thermal and mechanical parameters by introducing the heatspreader layer with specific thermal conductivity (at least 100 W/m-K) and mechanical properties. This parameter change creates a gradient structure that smoothly transitions thermal and mechanical stresses, reducing overall thermal stress and warpage in the package assembly.
3Loss of energy
If thermal conduction path is enhanced with heatspreader and through vias, then thermal dissipation efficiency is improved, but device complexity increases
Solution Approach 1:
The heatspreader layer serves multiple functions simultaneously: it acts as a thermal conduction path, a mechanical stress buffer, and a structural support element. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while achieving improved thermal dissipation efficiency.
Solution Approach 2:
The patent merges the thermal management function with the existing package structure by integrating the heatspreader layer into the bottom package assembly. The through-vias are combined with the heatspreader to create an integrated thermal conduction path, reducing the number of discrete components and simplifying the overall device structure.
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
Enhances thermal conductivity and mechanical stability, effectively mitigating thermal stress and warpage caused by thermal expansion mismatch, thereby improving the overall performance and reliability of PoP packages.
Implementation Method 1
Incorporating an interposer or heatspreader with thermally conductive through vias and thermal interface materials to provide a robust thermal conduction path
Implementation Method 2
reducing thermal stress and warpage by aligning thermal and mechanical properties between the top and bottom packages
Data Source
AI summary
A package on packaging structure provides for improved thermal conduction and mechanical strength by the introduction of a sold thermal coupler between the first and second packages. The first package has a first substrate and through vias through the first substrate. A first set of conductive elements is aligned with and coupled to the through vias of the first substrate. A solid thermal coupler is coupled to the first set of conductive elements and to a die of the second package. A second set of conductive elements is coupled to the die and a bottom substrate is coupled to the second set of conductive elements. The thermal coupler may be, e.g., an interposer, a heat spreader, or a thermal conductive layer.