Power Submodule Terminal Layout for Wire-Bond-Free Reliability

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Solution Overview

Problem

Existing power modules and submodules face reliability and cost issues due to wire-bonded top-side connections, which are prone to failure at higher current densities and temperatures, especially with wide bandgap semiconductors like SiC or GaN.

Innovation Solution

The power component design features terminal regions of contact elements at different heights on the same side of the power semiconductor device, allowing for reliable interconnections and simplified packaging, eliminating the need for robust metallization layers and reducing material and processing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wire-bonded top-side connections are used to connect power semiconductor devices, then electrical interconnection is achieved, but reliability deteriorates at higher current densities and temperatures

Engineering Contradiction:
Improveconnection reliabilityVSAvoidfailure risk at high current density and temperature
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the problematic wire bonding process and replaces it with direct bonding of contact elements to the power semiconductor device terminals. This eliminates the intermediate wire bond structure that is prone to failure under high current density and temperature conditions, directly addressing the reliability issue.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs asymmetric arrangement of contact elements at different heights on the same side of the device. This asymmetric design allows for optimized electrical and thermal pathways while improving connection reliability by distributing stress and heat differently compared to symmetric traditional designs.

Inventive Principle:
Principle #4Asymmetry

2Strength

If robust metallization layers are added to support heavy Cu wire bonding or soldering, then connection strength is improved, but material costs and processing costs increase

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent removes the requirement for robust metallization layers by directly bonding contact elements to the device terminals. This extraction of the metallization layer requirement eliminates the associated material costs (such as bond buffers) and processing costs while maintaining connection strength through direct contact.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses cost-effective contact elements that can be directly bonded without requiring expensive robust metallization layers. This approach replaces expensive materials and complex processing with simpler, more economical solutions that achieve the same connection strength.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If terminal regions are arranged at the same height for conventional packaging, then manufacturing simplicity is maintained, but interconnection reliability deteriorates

Engineering Contradiction:
Improveinterconnection reliabilityVSAvoidpackaging complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent transitions from a two-dimensional arrangement of terminal regions at the same height to a three-dimensional arrangement where contact elements are positioned at different heights on the same side. This dimensional change enables improved interconnection reliability by allowing separate bonding surfaces that reduce stress and improve thermal management, while the same-side arrangement keeps the packaging footprint compact.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4250350A1Power component, power submodule and power module
Publication Date: 2023.09.27 HITACHI ENERGY LTD
  • EP4250350A1 patent drawingFigure 1~3
  • EP4250350A1 patent drawingFigure 4~6
  • EP4250350A1 patent drawingFigure 7~8

AI summary

The power component (100) comprises a power semiconductor device (1) with a top side (10) and a bottom side (12), an electrically isolating body (2) surrounding the power semiconductor device as well as a first (3) and a second (4) contact element both in electrical contact with the power semiconductor device. The first and the second contact element each have a terminal region (30, 40) for externally electrically contacting the power component via the contact elements. The power component is configured to be operated with the first and second contact element lying on different electrical potentials. The terminal regions of the first and the second contact element are arranged on the same side of the power semiconductor device but at different heights with respect to the top side of the power semiconductor device.