Heat Spreader Top Surface Segmentation for Mold Flow
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Solution Overview
Problem
Semiconductor devices with heat spreaders face challenges in mold encapsulation due to solid top surfaces, leading to mold flowability issues and increased complexity and cost in side-gate molding, which prevents the use of top mold gates and affects heat dissipation.
Innovation Solution
A semiconductor package design featuring a heat spreader with a planar member and support members forming a cavity over the die, allowing for a non-tapered opening for encapsulant injection, which partially fills the opening and exposes the exterior surface for enhanced heat dissipation, enabling top mold gate usage and improved mold flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat spreader with solid top surface is used, then heat dissipation is improved, but top mold gate usage is prevented and device complexity increases
Solution Approach 1:
The heat spreader top surface is segmented into multiple regions: a first region with a first height and a second region with a second height lower than the first height. This segmentation allows the mold compound to access the cavity through the height difference while maintaining the heat spreader's thermal management function.
Solution Approach 2:
The invention introduces a vertical dimension (height difference) to the heat spreader top surface. By creating regions at different heights, the patent enables mold compound flow paths in the vertical direction, allowing top mold gate usage without requiring side channels or openings in the substrate.
2Reliability
If side-gate molding is used to encapsulate the device, then encapsulation is achieved, but mold flowability issues occur and manufacturing cost increases
Solution Approach 1:
Instead of creating channels or openings in the substrate to allow mold compound flow (conventional side-gate approach), the invention inverts the approach by creating height variations on the heat spreader top surface. This allows the mold compound to flow over the heat spreader surface rather than through substrate channels, simplifying the manufacturing process.
3Temperature
If the heat spreader top surface is fully exposed, then heat dissipation is maximized, but mold encapsulation becomes difficult
Solution Approach 1:
The heat spreader top surface has different local qualities: the first region maintains exposure for heat dissipation, while the second region has a lower height that facilitates mold compound flow. This local differentiation allows both heat dissipation and easy encapsulation to coexist.
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 enhances heat dissipation and reduces manufacturing complexity and costs by allowing for effective encapsulation and improved mold flowability, enabling the use of top mold gates while maintaining efficient heat transfer.
Implementation Method 1
The heat spreader will absorb the heat generated from the semiconductor device and transferred the heat to the ambient atmosphere
Data Source
AI summary
A semiconductor device has a substrate. A die is attached to a first surface of the substrate. A heat sink is provided having an approximately planer member and support members extending from the planer member. The support members are attached to the first surface of the substrate to form a cavity over the die with the planer member positioned above the die. An encapsulant is provided for encapsulating the device, wherein an exterior surface of the planer member is exposed. A non-tapered opening is formed in the planer member. The encapsulant is injected through the opening to encapsulate the cavity and the encapsulant will partially fill the non-tapered opening.