Transfer-Molded Power Module Pin Holder for Stress-Resistant Alignment

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Solution Overview

Problem

Prior semiconductor device module assemblies face alignment and mechanical stress issues due to misalignment of signal pin holders, leading to cracking of the epoxy molding compound during signal pin insertion and thermal cycling, which can result in module failure.

Innovation Solution

The implementation of an electronic device assembly with an electrically conductive signal pin holder pre-molded in a stress buffer material, where the stress buffer material has a lower modulus of elasticity than the signal pin holder and the molding compound, to absorb insertion and thermal stresses, and a frictional connection with the signal lead to secure the pin holder in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If signal pin holders are coupled to substrate via solder connection and molding operation is performed, then module assembly is completed, but alignment and tilt issues cause variation in holder opening locations

Engineering Contradiction:

Improvemodule assemblyVSAvoidsignal pin holder opening location

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The signal pin holders are pre-positioned and pre-aligned on the substrate before the molding operation is performed. This preliminary positioning ensures that the holders are correctly located and oriented, eliminating alignment and tilt issues that would otherwise cause variation in opening locations during subsequent assembly steps.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If signal pins are inserted into holders, then electrical connection is established, but mechanical stresses cause cracking of molding compound

Engineering Contradiction:

Improveelectrical connectionVSAvoidmolding compound

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

A stress buffer material is applied to the exterior surface of the signal pin holders before the molding operation. This buffer material acts as a cushion that absorbs mechanical stresses generated during signal pin insertion, preventing these stresses from being transmitted to the molding compound and causing cracks.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The stress buffer material serves as an intermediary layer between the signal pin holders and the molding compound. This intermediate layer decouples the mechanical stress transmission path, allowing the molding compound to be protected from insertion stresses while still providing structural support and encapsulation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If signal pin holders are misaligned, then assembly process is simplified, but insertion stresses and thermal cycling cause cracking

Engineering Contradiction:

Improveassembly processVSAvoidmodule reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The signal pin holders are pre-positioned and pre-aligned on the substrate before the molding operation. This preliminary positioning ensures that the holders are correctly located and oriented, eliminating alignment and tilt issues that would otherwise cause variation in opening locations during subsequent assembly steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 solution reduces the likelihood of cracking in the molding compound and enhances the reliability of the module by improving alignment and absorbing mechanical stresses associated with signal pin insertion and thermal cycling.

Implementation Method 1

the stress buffer material has a lower modulus of elasticity than the signal pin holder and the molding compound, to absorb insertion and thermal stresses

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a frictional connection with the signal lead to secure the pin holder in place

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS20240055334A1Transfer molded power modules and methods of manufacture

Publication Date: 2024.02.15 SEMICON COMPONENTS IND LLC

AI summary

In a general aspect, an electronic device assembly includes a circuit including at least one semiconductor die, and a signal lead electrically coupled with the circuit. The signal lead has a hole defined therethrough. The assembly further includes an electrically conductive signal pin holder disposed in the hole of the signal lead. The electrically conductive signal pin holder is electrically coupled with the signal lead. The assembly also includes a molding compound encapsulating, at least, the circuit; a portion of the signal lead including the hole; and a portion of the electrically conductive signal pin holder. An open end of the electrically conductive signal pin holder is accessible outside the molding compound.