SiC Semiconductor Electrode Hardness and Oxide Layer Protection

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Solution Overview

Problem

Existing semiconductor devices lack sufficient mechanical strength, particularly during the wire bonding process, due to the limitations of electrode materials and structures.

Innovation Solution

A semiconductor device with a vertical power semiconductor element featuring a SiC semiconductor layer, a first electrode layer, a harder second electrode layer, and an oxide layer, where the second electrode layer is electrically connected to a terminal and has a higher hardness than the first electrode layer, and the oxide layer is formed on the surface of the second electrode layer to enhance mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional electrode layer structure is used, then the device structure is simple, but the mechanical strength is insufficient during wire bonding

Engineering Contradiction:

Improvemechanical strengthVSAvoidelectrode layer structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The electrode layer is divided into multiple distinct layers (first electrode layer, second electrode layer, third electrode layer) with different materials and functions. Each layer serves a specific purpose: the first layer provides electrical connection, the second layer enhances mechanical strength and serves as bonding pad, and the third layer provides corrosion resistance. This segmentation resolves the contradiction by achieving high mechanical strength through layered structure while maintaining clear functional separation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs a composite electrode structure combining multiple materials (e.g., Al/Si/Mg in first layer, Ni in second layer, Au in third layer) to achieve properties that single materials cannot provide. The composite structure delivers both electrical conductivity and high mechanical strength for wire bonding, resolving the contradiction between structural simplicity and mechanical performance.

Inventive Principle:

Principle #40Composite materials

2Strength

If the second electrode layer is made harder than the first electrode layer, then mechanical strength improves, but manufacturing complexity increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidelectrode layer formation

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the material parameters of each electrode layer to achieve desired properties. The second electrode layer uses materials with higher hardness (Ni, Pd, Pt, or Ru) compared to the first layer (Al, AlSi, AlMg), enabling wire bonding while maintaining ease of manufacture through standard deposition techniques. This parameter change resolves the contradiction by achieving mechanical strength through material selection rather than complex processing.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20230109650A1Semiconductor device, semiconductor package, and methods for manufacturing these

Publication Date: 2023.04.06 ROHM CO LTD

AI summary

A semiconductor device includes a semiconductor layer that has a first main surface at one side and a second main surface at another side, a first main surface electrode that includes a first electrode covering the first main surface and a second electrode having a higher hardness than the first electrode and covering the first electrode, and an oxide layer that covers the first main surface electrode.