Double-Side Exposed Semiconductor Device Thermal Dissipation

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Solution Overview

Problem

Conventional semiconductor devices face challenges in thermal dissipation performance due to limited exposure areas for heat dissipation, requiring complex manufacturing processes and restricted heat dissipation capabilities.

Innovation Solution

A double-side exposed semiconductor device design where a bottom electrode of a semiconductor chip and a heat sink of a lead frame are exposed on two opposite sides, utilizing a thermal conductive second lead frame and an electrical conductive first lead frame with pins, and a molding compound encapsulation to enhance heat dissipation without increasing device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If only single-side exposure of drain is used for heat dissipation, then device structure is simple, but thermal dissipation performance is insufficient

Engineering Contradiction:

Improvethermal dissipation performanceVSAvoiddevice structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent transitions from single-side exposure to double-side exposure by utilizing both the top surface (through heat sink) and bottom surface (through drain electrode) for heat dissipation. This dimensional expansion effectively doubles the heat dissipation pathways without proportionally increasing device footprint, resolving the contradiction between thermal performance and structural simplicity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Temperature

If large area is exposed for heat dissipation, then thermal performance is improved, but device size increases

Engineering Contradiction:

Improvethermal dissipation performanceVSAvoiddevice footprint

Core Design Contradiction:

TemperatureVSArea of stationary object

Solution Approach 1:

By utilizing the vertical dimension and exposing heat dissipation surfaces on both top and bottom of the device, the patent effectively increases the total heat dissipation area without increasing the device's planar footprint. The heat sink on top and drain electrode on bottom work together to provide extensive thermal management within the same footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The drain electrode serves dual functions: as an electrical connection element and as a heat dissipation surface exposed on the bottom. This multi-functionality allows the same structural element to contribute to both electrical performance and thermal management, improving heat dissipation without adding separate components that would increase device size.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Temperature

If complex manufacturing process is used to achieve double-side exposure, then thermal dissipation performance is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveheat dissipation capabilityVSAvoidmanufacturing process

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent inverts the conventional approach by flipping the semiconductor chip upside down during assembly, with the drain facing downward for exposure. This inversion simplifies the manufacturing process compared to attempting to create openings in the packaging substrate for bottom exposure, as it naturally positions the drain for exposure without requiring complex substrate modification steps.

Inventive Principle:

Principle #13The other way round (Inversion)

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 double-side exposed design effectively improves thermal dissipation performance by exposing heat sinks and electrodes on both sides of the semiconductor device, enhancing heat management without enlarging the device footprint.

Implementation Method 1

a thermal conductive and electrical non-conductive second lead frame

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

A molding compound is deposited to encapsulate the flipped chip and the center portions of the first and second lead frames

Methodology Applied

Scientific EffectEncapsulation: Physical Containment

Data Source

PatentUS8933545B2Double-side exposed semiconductor device

Publication Date: 2015.01.13 ALPHA & OMEGA SEMICONDUCTOR (CAYMAN) LTD

AI summary

A double-side exposed semiconductor device includes an electric conductive first lead frame attached on top of a thermal conductive but electrical nonconductive second lead frame and a semiconductor chip flipped and attached on top of the first lead frame. The gate and source electrodes on top of the flipped chip form electrical connections with gate and source pins of the first lead frame respectively. The flipped chip and center portions of the first and second lead frames are then encapsulated with a molding compound, such that the heat sink formed at the center of the second lead frame and the drain electrode at bottom of the semiconductor chip are exposed on two opposite sides of the semiconductor device. Thus, heat dissipation performance of the semiconductor device is effectively improved without increasing the size of the semiconductor device.