Power Semiconductor Module Casting to Prevent Lid Leakage

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Solution Overview

Problem

The existing methods for producing power semiconductor modules face challenges in preventing the casting compound from leaking out of the housing during the heating step, as the liquid material can wet the lid and escape due to capillary effects and expansion, potentially damaging the module and affecting its performance and lifespan.

Innovation Solution

The method involves pouring the liquid or viscous material into the housing cavity first and then arranging the lid with functional elements that extend into the material, ensuring the lid is not in contact with the material until it is hardened, thereby reducing the risk of leakage by minimizing capillary effects and allowing for easier filling and curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the lid is arranged on the sidewalls before pouring the liquid material, then the housing structure is established early, but the liquid material can wet the lid and leak out during heating

Engineering Contradiction:

Improveprevention of material leakageVSAvoidsequence of operations

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The lid is arranged on the sidewalls before pouring the liquid material, establishing the housing structure in advance. This preliminary action allows the functional elements to be positioned correctly before material filling, preventing leakage during the subsequent heating process while maintaining a systematic production sequence

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the lid is arranged after pouring the liquid material, then material leakage is prevented, but the functional elements cannot be properly positioned in the material

Engineering Contradiction:

Improveprevention of material leakageVSAvoidpositioning of functional elements

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The functional elements are arranged on the lid before the lid is mounted on the sidewalls. This preliminary positioning ensures that when the lid is in place, the functional elements are correctly positioned to extend into the liquid material at the appropriate locations, maintaining manufacturing precision while preventing leakage

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the liquid material is heated to evaporate liquid and harden the pre-layer, then the casting compound is formed, but capillary effects cause the material to wet the lid and leak out

Engineering Contradiction:

Improvecuring process efficiencyVSAvoidcapillary effects causing leakage

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The functional elements are extracted from the lid structure and positioned to extend into the liquid material, creating a physical barrier that prevents the liquid material from contacting and wetting the lid surface during heating, thereby eliminating the capillary effect that causes leakage

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If the lid completely covers the cavity, then protection is provided, but the functional elements cannot extend into the material to control the filling process

Engineering Contradiction:

Improveprotection of componentsVSAvoidintegration of functional elements

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The lid is designed with local variations in coverage: it completely covers the housing opening for protection, but includes functional elements that locally extend into the liquid material. This creates different zones with different functions - the lid provides general protection while the functional elements provide localized control over the material filling and curing process

Inventive Principle:

Principle #3Local quality

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 approach effectively prevents the casting compound from leaking out of the housing, enhancing the reliability and longevity of the power semiconductor module by maintaining the material within the housing and allowing for more efficient filling and curing processes.

Implementation Method 1

A heating step may follow during which liquid that is present in the pre-layer is at least partly evaporated. In this way, the pre-layer is hardened to form the resulting casting compound.

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

There is a risk that a lid of the housing is wetted by the material of the casting compound during the heating step. The material may then unintentionally leak out of the housing... ensuring the lid is not in contact with the material until it is hardened, thereby reducing the risk of leakage by minimizing capillary effects

Methodology Applied

Scientific EffectCapillary effect: Capillary Action

Data Source

PatentEP4276888A1Method for producing a power semiconductor module

Publication Date: 2023.11.15 INFINEON TECHNOLOGIES AG

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AI summary

A method comprises pouring a liquid, semi-liquid or viscous material into a cavity formed by sidewalls of a housing, thereby covering a substrate that is arranged in the cavity formed by the sidewalls, arranging a lid on the sidewalls, thereby covering the cavity formed by the sidewalls, wherein the lid comprises at least one functional element that extends from the lid into the liquid, semi-liquid or viscous material in a direction towards the substrate once the lid is in its final mounting position, and curing the liquid, semi-liquid or viscous material in order to form a casting compound.