Semiconductor Module Wiring Substrate Mounting on Heat Sink

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Solution Overview

Problem

Current semiconductor modules face challenges in achieving high mounting accuracy and reducing manufacturing cycle time due to difficulties in securing mounting accuracy on the X-Y plane and controlling height along the Z axis when mounting and bonding wiring substrates or sub-mounts with semiconductor elements onto heat sinks.

Innovation Solution

A semiconductor module configuration that includes a wiring substrate with semiconductor elements, a heat sink, a binder, and supports formed on the heat sink, where the binder is positioned between the wiring substrate and heat sink, and the supports are arranged to surround the binder, allowing for provisional fixation and bonding without requiring prolonged tool holding, thereby enhancing accuracy and reducing cycle time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a binder is used to bond the wiring substrate to the heat sink, then thermal conductivity is improved, but mounting accuracy and height control deteriorate

Engineering Contradiction:

Improveheat dissipationVSAvoidmounting accuracy

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The bonding structure is divided into two independent parts: a binder in the die pad area for thermal bonding, and separate supports in the peripheral area for mechanical positioning. This segmentation allows each component to perform its specialized function without interfering with the other, resolving the contradiction between thermal conductivity and mounting accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The supports act as intermediary elements that provide mechanical positioning and height control during the bonding process. These supports are formed apart from the binder, allowing the wiring substrate to be accurately positioned before the binder sets, thus maintaining mounting accuracy while still achieving good thermal contact through the binder.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If a mounting head tool holds the sub-mount for a long time to achieve mounting accuracy, then mounting precision is improved, but productivity deteriorates

Engineering Contradiction:

Improvemounting accuracyVSAvoidmounting speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The supports are formed in advance in the peripheral area of the heat sink, creating pre-positioned reference points for mounting. When the wiring substrate is placed, these pre-formed supports automatically provide positioning and height control, eliminating the need for prolonged holding by the mounting head tool and thereby improving productivity while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If the binder and support are formed together, then device complexity is reduced, but mounting accuracy and height control deteriorate

Engineering Contradiction:

Improvestructure simplicityVSAvoidheight control

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

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 enables high-accuracy mounting of semiconductor elements onto heat sinks in a shorter time by stabilizing the wiring substrate and heat sink during bonding, reducing misalignment and cycle time, while maintaining electrical and thermal connectivity.

Implementation Method 1

a binder which is formed in a die pad area on the heat sink so as to be present between the wiring substrate and the heat sink, and bonds the wiring substrate and the heat sink

Methodology Applied

Scientific EffectThermal bonding:

Implementation Method 2

a support which is formed in a peripheral part of the die pad area on the heat sink, and fixes the wiring substrate to the heat sink by being in contact with a peripheral part of the second surface of the wiring substrate

Methodology Applied

Scientific EffectMechanical contact fixation: Mechanical Fastener

Data Source

PatentUS10305008B2Semiconductor module and method for manufacturing the same

Publication Date: 2019.05.28 PANASONIC SEMICON SOLUTIONS CO LTD

AI summary

A semiconductor module includes: one or more semiconductor elements; a wiring substrate having a first surface on which the one or more semiconductor elements are mounted, the wiring substrate being electrically connected to the one or more semiconductor elements; a heat sink on which the wiring substrate is mounted, the heat sink facing a second surface of the wiring substrate on a reverse side of the first surface; a binder which is formed in a die pad area on the heat sink so as to be present between the wiring substrate and the heat sink, and bonds the wiring substrate and the heat sink; and a support which is formed in a peripheral part of the die pad area on the heat sink, and fixes the wiring substrate to the heat sink by being in contact with a peripheral part of the second surface of the wiring substrate.