Semiconductor Conductive Post Mechanical Fixation

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Solution Overview

Problem

Semiconductor devices, particularly IGBT modules, face limitations in allowing large currents due to heat-related issues at the interfaces between conductive posts and support plates, leading to increased electrical resistance and potential disconnection, as the low-melting point materials used for connections are prone to heat-induced failure.

Innovation Solution

The semiconductor device employs a structure with conductive posts that are mechanically fixed to the support plate using a deformation process, eliminating low-melting point materials and enhancing the contact area to improve conductivity and heat dissipation, allowing for a larger allowable current by using copper or aluminum posts with a coating for corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If low-melting point materials (solder, silver solder) are used to connect conductive posts and support plate, then ease of manufacture is improved, but reliability deteriorates due to heat-induced failure and increased electrical resistance

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention extracts and eliminates the low-melting point connection materials (solder, silver solder) from the interface between conductive posts and support plate. By removing these problematic materials, the patent avoids heat-induced failures and electrical resistance issues while maintaining manufacturing feasibility through direct mechanical insertion and deformation fixation methods.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary deformation fixation mechanism (bending the conductive post to engage with the support plate) that replaces the thermal bonding process. This intermediary mechanical fixation method enables reliable connection without using low-melting point materials, resolving the contradiction between ease of manufacture and reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If large current is allowed to flow through conductive posts, then power handling capability is improved, but temperature increases causing harmful effects on connection stability

Engineering Contradiction:
ImprovepowerVSAvoidtemperature
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful thermal effect into a beneficial mechanical fixation mechanism. By utilizing the deformation of the conductive post (caused by insertion force or thermal expansion) to create a mechanical lock with the support plate, the patent transforms potential thermal damage into a strengthening fixation method that improves connection stability under high current conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The invention changes the connection mechanism from thermal bonding (dependent on material melting temperature) to mechanical deformation (dependent on elastic/plastic properties). This parameter change allows the connection to withstand higher temperatures and larger currents without relying on low-melting point materials, thereby improving power handling capability while managing thermal effects.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If contact area between conductive post and support plate is increased, then electrical conductivity is improved, but device complexity increases

Engineering Contradiction:
Improveelectrical conductivityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention transitions from a point-contact or small-area connection to a distributed line-contact or surface-contact configuration by deforming the conductive post to wrap around or engage with multiple points on the support plate. This dimensional change in the contact geometry increases the effective contact area and improves electrical conductivity without significantly increasing device complexity, as the deformation is achieved through the insertion process itself.

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

This configuration enables the semiconductor device to handle higher currents without significant increases in electrical resistance, improving reliability and performance by reducing thermal stress and oxidation, thus allowing currents up to 63 A per conductive post or 945 A in total for multiple posts.

Implementation Method 1

conductive posts that are mechanically fixed to the support plate using a deformation process

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

allowing for a larger allowable current by using copper or aluminum posts with a coating for corrosion resistance

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

improving reliability and performance by reducing thermal stress and oxidation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2339625B1Semiconductor device and fabrication method therefor
Publication Date: 2015.01.07 IBIDEN CO LTD
  • EP2339625B1 patent drawingFigure 1
  • EP2339625B1 patent drawingFigure 2
  • EP2339625B1 patent drawingFigure 3~4

AI summary

A semiconductor device (101) includes a support plate (30), a semiconductor element (10), and a conductive post (40) formed by a columnar conductor having a first end portion (41a) at one end and a second end portion (42a) at the other end. The support plate (30) has a plurality of holes (30b) formed therein, and a conductor (33) formed on a wall surface of the hole (30b). The second end portion (42a) of the conductive post (40) is connected to electrodes (12 to 14) of the semiconductor element (10) via conductive materials (72a to 72c). A side surface of the conductive post (40) is fixed to the wall surface of the hole (30b) deformed by pressing force of the conductive post (40) on a side closer to the first end portion (41a) than the second end portion (42a).