Semiconductor Device With Segmented Heat Dissipating And Wiring Substrates

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Solution Overview

Problem

Existing semiconductor devices face challenges in efficiently dissipating heat and supporting high current while maintaining a reduced size, particularly for field-effect transistors (FETs) with high heat resistance temperatures, due to limitations in thermal conductivity and electrical resistivity of materials used in current substrates.

Innovation Solution

A semiconductor device design that separates the functions between a high thermal conductivity heat dissipating substrate and a low thermal conductivity wiring substrate, with the wiring conductor made of silver or copper located inside the wiring substrate, allowing for efficient heat dissipation and high current support without increasing device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a metal base substrate with high thermal conductivity is used to improve heat dissipation, then heat dissipation efficiency is improved, but the substrate cannot support high current due to high electrical resistivity of the metal material

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidcurrent carrying capacity

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The invention divides the substrate into two separate functional layers: a heat dissipation substrate made of ceramic material for thermal management, and a wiring substrate containing low-resistivity metal wiring conductors for electrical current transmission. This segmentation allows each layer to optimize its specific function without compromise.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining ceramic material (for heat dissipation) and metal material (for electrical conduction). The ceramic wiring substrate provides both thermal management properties and serves as a carrier for low-resistivity metal wiring conductors, achieving both heat dissipation and high current support capabilities.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the cross-sectional area of the wiring conductor is increased to support high current, then current carrying capacity is improved, but the device size increases

Engineering Contradiction:

Improvecurrent carrying capacityVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The invention changes the material parameter of the wiring conductor from high-resistivity metal (tungsten, molybdenum) to low-resistivity metal (silver, copper). This parameter change allows the wiring conductor to support high current with a smaller cross-sectional area, thereby reducing device size while maintaining current carrying capacity.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If metal wiring conductors with low electrical resistivity are formed only on the substrate surface, then current carrying capacity is improved, but the device size increases due to increased substrate area

Engineering Contradiction:

Improvecurrent carrying capacityVSAvoidsubstrate area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The invention transitions the wiring conductor from a two-dimensional surface configuration to a three-dimensional embedded structure within the ceramic wiring substrate. The wiring conductor is formed inside the substrate thickness direction, allowing efficient current conduction without increasing the substrate's planar area, thus maintaining compact device dimensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 enables effective heat dissipation and high current support while minimizing device size, suitable for FETs with high heat resistance temperatures, and allows for the mounting of heat-sensitive electronic components without significant temperature increase on the wiring substrate.

Implementation Method 1

a heat dissipating substrate having a relatively high thermal conductivity

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a wiring conductor made mainly of silver or copper and located inside the wiring substrate

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9030005B2Semiconductor device

Publication Date: 2015.05.12 MURATA MFG CO LTD

AI summary

In a semiconductor device including a semiconductor element that produces heat and a substrate on which the semiconductor element is mounted, functions of the substrate are divided between a heat dissipating substrate and a wiring substrate. The heat dissipating substrate has a relatively high thermal conductivity, and includes principal surfaces defined by electric insulators, one of which is provided with an outer conductor located thereon. The wiring substrate is mounted on the upper principal surface of the heat dissipating substrate, has a thermal conductivity lower than that of the heat dissipating substrate, and includes a wiring conductor made mainly of silver or copper and located inside the wiring substrate, the wiring conductor being electrically connected to the outer conductor. The semiconductor element is mounted on the upper principal surface of the heat dissipating substrate and disposed in a through hole of the wiring substrate.