Molded Underfill Structures for Heat-Dissipating Die Assemblies
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Solution Overview
Problem
Vertically stacked semiconductor die packages face challenges with heat dissipation due to the low thermal conductivity of conventional capillary underfill materials, which also form inconsistent fillets that interfere with heat dissipation and complicate the use of lid-type heat spreaders.
Innovation Solution
The use of high thermal conductivity molded underfill materials that can be loaded with high concentrations of thermal conductivity particles, allowing for consistent distribution and reduced fillet formation, facilitating efficient heat dissipation and compatibility with conformal heat spreaders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional capillary underfill materials are used in vertically stacked die packages, then the package structure is formed, but heat dissipation is poor due to low thermal conductivity
Solution Approach 1:
The patent changes the thermal conductivity parameter of the underfill material by loading it with high concentrations of thermally conductive particles (such as aluminum oxide, aluminum nitride, or boron nitride), transforming it from a low thermal conductivity material to a high thermal conductivity material capable of effective heat dissipation
Solution Approach 2:
The patent creates a composite underfill material by combining the base polymer matrix with thermally conductive particles, forming a composite structure that maintains the adhesive and structural properties of the original underfill while adding superior thermal conduction capabilities
2Shape
If conventional underfill materials are used, then the die stack is supported, but inconsistent fillet formation occurs that interferes with heat dissipation and complicates heat spreader integration
Solution Approach 1:
The patent modifies the rheological parameters of the underfill material, specifically its viscosity and flow characteristics, to enable consistent fillet formation during the dispensing process, ensuring uniform shapes that do not interfere with heat spreader integration
Solution Approach 2:
The patent performs preliminary formulation and characterization of the underfill material to pre-determine its flow and curing properties, ensuring that when the material is applied, it automatically forms consistent fillets without requiring additional processing or adjustment
3Productivity
If vertically stacked die packages are implemented to increase processing power, then functional capacity increases, but operating temperatures exceed maximum limits
Solution Approach 1:
The patent introduces a thermal intermediary solution by using the high thermal conductivity underfill material as a thermal pathway between the stacked dies and the heat spreader, effectively mediating heat transfer and preventing temperature buildup that would otherwise limit processing power
Solution Approach 2:
The patent addresses the thermal management problem by adding a thermal conduction dimension to the underfill material, transforming it from a purely mechanical adhesive into a dual-function material that provides both structural support and active heat dissipation pathways
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 high thermal conductivity of molded underfill materials enhances heat dissipation from semiconductor dies, maintaining thermal coupling with heat spreaders and improving package reliability by reducing temperature increases and geometric inconsistencies.
Implementation Method 1
The high thermal conductivity of molded underfill materials enhances heat dissipation from semiconductor dies, maintaining thermal coupling with heat spreaders
Data Source
AI summary
A semiconductor die assembly in accordance with an embodiment of the present technology includes first and second semiconductor dies and a package substrate carrying the first and second semiconductor dies. The second semiconductor die includes a first peripheral portion extending laterally outward beyond a first edge surface of the first semiconductor die. Similarly, the package substrate includes a second peripheral portion extending laterally outward beyond a second edge surface of the second semiconductor die. The semiconductor die assembly further includes a first volume of molded underfill material between the first and second semiconductor dies, a second volume of molded underfill material between the package substrate and the second semiconductor die, a first molded peripheral structure laterally adjacent to the first edge surface of the first semiconductor die, and a second molded peripheral structure laterally adjacent to the second edge surface of the second semiconductor die.