Power Module Batch Soldering With Customized Joint Thickness

Solution Overview

Problem

Conventional batch soldering techniques are unable to customize soldered joints to meet the varying requirements of high tensile strength and low ductility needed for semiconductor power modules, as they are not well-suited for individual customization.

Innovation Solution

A common soldering step is performed to simultaneously form soldered joints with different characteristics by using a thick layer of solder paste for one joint and an ultra-thin preformed solder for the other, without mechanical pressure, allowing for the formation of intermetallic phases with higher melting points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional batch soldering techniques are used, then production efficiency is improved, but the ability to customize soldered joints for different mechanical requirements deteriorates

Engineering Contradiction:

Improveproduction efficiencyVSAvoidcustomization capability

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by using different solder material thicknesses (thick solder paste for passive devices, ultra-thin preformed solder for semiconductor dies) and different solder material types within the same batch process. This allows each soldered joint to have customized properties (ductility for passive devices, tensile strength for semiconductor dies) while maintaining batch processing efficiency.

Inventive Principle:

Principle #3Local quality

2Strength

If ultra-thin preformed solder is used for semiconductor dies, then tensile strength is improved, but ductility deteriorates

Engineering Contradiction:

Improvetensile strengthVSAvoidductility

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by using different solder material thicknesses (thick solder paste for passive devices, ultra-thin preformed solder for semiconductor dies) and different solder material types within the same batch process. This allows each soldered joint to have customized properties (ductility for passive devices, tensile strength for semiconductor dies) while maintaining batch processing efficiency.

Inventive Principle:

Principle #3Local quality

3Loss of time

If a common soldering step is used, then processing time is reduced, but control over individual joint characteristics deteriorates

Engineering Contradiction:

Improveprocessing timeVSAvoidjoint characteristic control

Core Design Contradiction:

Loss of timeVSManufacturing precision

Solution Approach 1:

The patent applies local quality by using different solder material thicknesses (thick solder paste for passive devices, ultra-thin preformed solder for semiconductor dies) and different solder material types within the same batch process. This allows each soldered joint to have customized properties (ductility for passive devices, tensile strength for semiconductor dies) while maintaining batch processing efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies preliminary action by pre-forming the solder materials with specific thicknesses and properties before the batch soldering process. The thick solder paste is prepared for passive devices and the ultra-thin preformed solder is prepared for semiconductor dies, so that when the common soldering step is applied, each joint automatically receives the appropriate material characteristics without requiring individual customization during soldering.

Inventive Principle:

Principle #10Preliminary action

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 method enables efficient batch processing of semiconductor power modules with customized soldered joints that meet specific mechanical and thermal stress requirements, reducing production time and cost while maintaining reliability.

Implementation Method 1

the region of second solder material melts and reacts with the metal joining surface of the semiconductor die and the second metal region of the substrate to form one or more intermetallic phases within the second soldered joint

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

The common soldering step is performed at a soldering temperature such that the region of second solder material melts

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS12394769B2Batch soldering of different elements in power module

Publication Date: 2025.08.19 INFINEON TECHNOLOGIES AG

AI summary

An electronic device includes a substrate including first and second metal regions, a first passive device that includes a metal joining surface and is arranged on the substrate with the metal joining surface of the first passive device facing first metal region, a semiconductor die that includes a metal joining surface and is arranged on the substrate with the metal joining surface of the semiconductor die facing the second metal region, a first soldered joint between the metal joining surface of the first passive device and the first metal region; and a second soldered joint between the metal joining surface of the semiconductor die and the second metal region, wherein a minimum thickness of the first soldered joint is greater than a maximum thickness of the second soldered joint.