Lead-Frame Package Top-Side Thermal Path for Better Heat Dissipation
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Solution Overview
Problem
Existing lead-frame packages face challenges in efficiently dissipating heat generated by semiconductor ICs, primarily due to a single primary heat dissipation path through the thermal die pad to the PCB, which limits the amount and rate of heat dissipation, and is further compromised by potential voids in the die attach substance.
Innovation Solution
The introduction of a thermal dissipation surface on the top surface of the lead-frame package, coupled with thermally conductive paths and finned protrusions, provides additional heat dissipation pathways, enhancing heat transfer away from the semiconductor IC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a single primary heat dissipation path through the thermal die pad to the PCB is used, then the package structure remains simple, but the heat dissipation efficiency is limited
Solution Approach 1:
The heat dissipation function is segmented into multiple independent paths: (1) the traditional path through the thermal die pad to the PCB, and (2) a new path through the thermal dissipation surface on the lead-frame package. This segmentation allows heat to be dissipated through multiple channels simultaneously, improving overall heat dissipation efficiency without requiring a complete redesign of the package structure.
Solution Approach 2:
The invention adds a new heat dissipation dimension by introducing the thermal dissipation surface on the lead-frame package body. Instead of relying solely on the bottom-side thermal die pad path, heat can now escape through the top surface via the thermal dissipation surface, effectively utilizing the third dimension (vertical heat flow) to improve thermal management.
2Temperature
If the die attach substance contains voids, then the manufacturing process remains simple, but the heat dissipation path is compromised
Solution Approach 1:
The thermal dissipation surface acts as an intermediary heat dissipation interface between the semiconductor IC and the external environment. By providing this alternative thermal pathway, the system reduces its dependency on the die attach substance quality, as heat can bypass voids in the die attach material through the lead-frame's thermal dissipation surface.
Solution Approach 2:
The invention changes the thermal conduction parameters by introducing a new thermal pathway with different thermal resistance characteristics. The thermal dissipation surface provides a parallel thermal path with potentially lower resistance, compensating for the degraded thermal performance caused by voids in the die attach substance.
3Temperature
If only the bottom surface is used for heat dissipation, then the surface area for heat transfer is limited, but the package design remains simple
Solution Approach 1:
The heat dissipation surface area is segmented across two distinct locations: the bottom surface (thermal die pad) and the top surface (thermal dissipation surface). This segmentation effectively doubles the available heat transfer areas, allowing heat to be dissipated from both the top and bottom of the package simultaneously.
Solution Approach 2:
The invention utilizes the top surface dimension for heat dissipation, transforming the heat dissipation geometry from a single-sided (bottom-only) configuration to a dual-sided configuration. This dimensional utilization effectively increases the heat transfer surface area without significantly increasing package volume.
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 configuration significantly improves heat dissipation from the semiconductor IC, increasing performance and reliability, especially in harsh environments, by providing multiple thermal paths and increasing the surface area for heat transfer.
Implementation Method 1
a thermal dissipation surface at the second surface of the lead-frame package thermally coupled to the semiconductor IC. In some embodiments, the thermal dissipation surface provides a thermal dissipation path from the semiconductor IC to the second surface of the lead-frame package
Implementation Method 2
the lead-frame package further comprises a plurality of finned protrusions extending from the thermal dissipation surface
Implementation Method 3
a plurality of finned protrusions extending from the thermal dissipation surface
Data Source
AI summary
An example lead-frame package, a method of manufacturing a lead-frame package, and an electrical system comprising a lead-frame package with improved heat dissipation are provided. An example lead-frame package with improved heat dissipation includes a first surface and a second surface opposite the first surface. The example lead-frame package further includes a semiconductor integrated circuit (IC) thermally coupled to a die pad, the die pad forming a portion of the first surface of the lead-frame package. The example lead-frame package further includes a thermal dissipation surface at the second surface of the lead-frame package thermally coupled to the semiconductor IC. The thermal dissipation surface provides a thermal dissipation path from the semiconductor IC to the second surface of the lead-frame package.