Stepped Lead Frame Structure for Semiconductor Heat Dissipation
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Solution Overview
Problem
Semiconductor devices with built-in electronic components face challenges in effectively dissipating heat due to the low thermal conductivity of encapsulating resin, which limits heat dissipation efficiency, especially when large amounts of heat need to be removed.
Innovation Solution
A semiconductor device design featuring a metal lead frame with exposed side surfaces and a heat sink, connected to a wiring substrate via connection members, and filled with encapsulating resin containing inorganic or metal fillers to enhance thermal conductivity, allowing efficient heat dissipation from electronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electronic components are built-in between two organic substrates with encapsulating resin, then high-density component mounting is achieved, but heat dissipation efficiency deteriorates due to low thermal conductivity of encapsulating resin
Solution Approach 1:
The lead frame is divided into multiple regions with different surface heights (first surface at higher level, second surface at lower level), creating stepped regions that expose different portions to the encapsulating resin. This segmentation allows heat to be dissipated through multiple pathways - through the encapsulating resin from the first surface and through direct exposure from the second surface - thereby improving heat dissipation efficiency while maintaining the compact built-in structure
Solution Approach 2:
The invention transitions from a conventional flat lead frame structure to a three-dimensional stepped structure with varying surface heights. By creating vertical dimensionality differences (first surface higher than second surface), the patent exposes different areas of the lead frame to the encapsulating resin, enabling heat to escape through multiple spatial pathways and improving thermal management in the vertical dimension
2Reliability
If peripheries of built-in electronic components are covered with encapsulating resin, then component protection and high-density mounting are achieved, but heat dissipation efficiency deteriorates
Solution Approach 1:
Different regions of the lead frame are given different properties regarding encapsulating resin coverage. The first surface region is covered with encapsulating resin for protection, while the second surface region remains exposed to facilitate heat dissipation. This local differentiation allows simultaneous achievement of component protection where needed and heat dissipation where required
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 design significantly enhances heat dissipation efficiency by utilizing the high thermal conductivity of the metal lead frame and fillers, effectively managing heat generated by electronic components within the semiconductor device.
Implementation Method 1
the heat generated by the electronic components is conducted through the organic substrates from metal terminals whose thermal conductivity is high and is dissipated
Implementation Method 2
encapsulating resin containing inorganic or metal fillers to enhance thermal conductivity, allowing efficient heat dissipation from electronic components
Data Source
AI summary
A semiconductor device includes: a lead frame that is formed of metal; a wiring substrate that is opposed to the lead frame; an electronic component that is disposed between the lead frame and the wiring substrate; a connection member that connects lead frame and the wiring substrate; and encapsulating resin that is filled between the lead frame and the wiring substrate and covers the electronic component and the connection member. The lead frame includes: a first surface opposed to the wiring substrate and covered by the encapsulating resin; a second surface located on a back side of the first surface and exposed from the encapsulating resin; and a side surface neighboring first surface or the second surface, at least a portion of the side surface exposed from the encapsulating resin.