Heat Spreader Extending Into Stiffener Well for Thin Die Rigidity
Solution Overview
Problem
Conventional semiconductor packages face challenges in providing adequate thermal protection and rigidity, especially when using thin dies, as the thickness of the die and stiffener ring significantly impact warping resistance and solder joint reliability.
Innovation Solution
A semiconductor package design that includes a substrate, a stiffener ring forming a well with the substrate, and a heat spreader coupled to the stiffener, where the heat spreader's bottom portion extends into the well, thermally couples with the die through a thermal interface, enhancing rigidity and heat dissipation without increasing the package thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If thin dies are used to reduce package thickness, then the package form factor is compact, but the rigidity and warping resistance deteriorate
Solution Approach 1:
The heat spreader extends vertically into the well formed by the substrate and stiffener ring, utilizing the third dimension (depth) to provide structural support and rigidity without increasing the horizontal footprint or overall package thickness. This vertical extension allows thin dies to be used while maintaining package rigidity through the heat spreader's protruding structure.
2Temperature
If adequate thermal protection is provided, then heat dissipation improves, but the package complexity increases
Solution Approach 1:
The heat spreader performs multiple functions simultaneously: it provides thermal management by conducting heat away from the die, offers structural support and rigidity to the package, and acts as a mechanical component filling the well. This multi-functionality improves heat dissipation without significantly increasing package complexity, as a single component achieves multiple objectives.
3Strength
If the heat spreader extends into the well, then rigidity increases, but the assembly complexity increases
Solution Approach 1:
The well is pre-formed by the substrate and stiffener ring assembly before the heat spreader is installed. This preliminary structuring provides a ready-made receptacle that guides the heat spreader into its final position, simplifying the assembly process despite the heat spreader's extended geometry. The pre-formed well ensures proper alignment and positioning without requiring complex assembly operations.
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 design improves the assembly process, increases heat dissipation, and enhances solder joint reliability in temperature cycle testing, while maintaining a compact package form factor.
Implementation Method 1
A thermal interface material 116 may be inserted between the die 102 and the heat spreader 112
Data Source
AI summary
A semiconductor package includes a substrate, a stiffener ring coupled to the substrate and configured to form a well with the substrate, and a die positioned in the well. A thermal interface is positioned on the die. A heat spreader is coupled to the stiffener ring so that a portion of the heat spreader is positioned in the well and the thermal interface thermally couples the heat spreader to the die. The portion of the heat spreader positioned in the well adds rigidity to the semiconductor package and facilitates the use of thin dies.