Heat-Dissipating Lead Frame With Direct Chip Contact for Dense Packages
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Solution Overview
Problem
Conventional semiconductor packages face limitations in heat dissipation, particularly for large-scale circuits and smaller semiconductor chips, with existing heat sinks not directly attached to the chip, leading to insufficient heat dissipation and increased noise.
Innovation Solution
A semiconductor device package with a heat-dissipating lead frame featuring a central opening and concave areas on the front surface, equipped with heat-dissipating portions and a mounting surface for the semiconductor element, allowing direct attachment to the rear surface for enhanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat sink is attached to the central opening of the substrate, then heat dissipation effect is improved to some extent, but the heat dissipation efficiency cannot be sufficiently increased because the heat sink is not directly attached to the semiconductor chip
Solution Approach 1:
The patent combines the heat dissipation function directly into the lead frame structure by forming heat dissipation fins on the lead frame itself, merging the electrical connection function and heat dissipation function into a single integrated component. This eliminates the need for separate heat sink attachments while achieving direct heat dissipation from the semiconductor chip.
Solution Approach 2:
The lead frame serves as an intermediary component that directly contacts both the semiconductor chip mounting surface and the heat dissipation fins. The lead frame acts as a thermal mediator, conducting heat directly from the chip through its structure to the external environment, eliminating thermal gaps that would exist with separate heat sink attachments.
2Productivity
If the semiconductor chip size is reduced and circuit scale is increased, then integration density is improved, but heat dissipation becomes more difficult due to increased heat generation in a smaller area
Solution Approach 1:
The patent transitions heat dissipation from a two-dimensional substrate surface to a three-dimensional structure by forming vertical heat dissipation fins on the lead frame. This dimensional change increases the heat dissipation surface area without increasing the package footprint, enabling effective heat dissipation for high-density, small-sized semiconductor chips.
Solution Approach 2:
The patent concentrates heat dissipation capability at the critical location where the semiconductor chip is mounted on the lead frame. The heat dissipation fins are specifically positioned and configured at the chip mounting area, providing localized high-performance heat dissipation where it is most needed, rather than distributing heat dissipation uniformly across the entire package.
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 solution provides effective heat dissipation by directly attaching the heat-dissipating lead frame to the semiconductor chip, improving thermal management and reducing noise in semiconductor packages.
Implementation Method 1
Joule heat generated from the semiconductor chip or the like is transmitted to the lead frame (through the die bonding resin) or is dissipated to the outside of the package through the substrate on which the semiconductor chip is mounted
Implementation Method 2
a number of heat-dissipating portions provided around the mounting portion and/or on a rear surface side opposite to the mounting surface
Implementation Method 3
the bottom part of the lead frame, in particular, to which the semiconductor chip is die-bonded, is exposed to the outside
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
To provide a lead frame with a high heat dissipation effect capable of taking effective heat dissipation measures even for semiconductor chips in large-scale circuits. A heat-dissipating lead frame includes: a mounting surface for mounting a semiconductor chip formed of a material having heat dissipation properties and provided at a center on a front surface side of a mounting portion; and a number of heat-dissipating portions composed of a number of plate-shaped heat-dissipating fins provided around the mounting portion. With the mounting front surface facing the front surface of the semiconductor package, the mounting surface is fitted into an opening provided in a semiconductor device package, and the lead frame is attached to the rear surface of the semiconductor device package.