SiC Wafer Sidewall Orientation for Accurate Pickup

Solution Overview

Problem

SiC semiconductor devices with inclined surfaces pose a challenge during pickup in semiconductor assembly apparatuses, leading to potential pickup errors due to obstruction by the inclined surfaces.

Innovation Solution

The SiC semiconductor device is designed with specific surface orientations, including a first main surface facing a c-plane and a side surface facing an a-plane, where the side surface has an angle less than the off angle with respect to the normal, reducing the formation region of inclined surfaces along the c-axis, thereby minimizing pickup errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the SiC semiconductor layer has inclined surfaces oriented along the c-axis, then the manufacturing process is simplified and cutting efficiency is improved, but pickup error occurs in semiconductor assembly apparatus

Engineering Contradiction:

Improvecutting efficiencyVSAvoidpickup accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by creating different surface characteristics in different regions of the SiC semiconductor layer. The front surface maintains the inclined surface for efficient cutting, while the back surface is designed to be substantially flat to enable reliable pickup. This localized differentiation allows each surface to optimize its function without compromising the other.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the conventional approach by making the back surface (pickup surface) flat while keeping the front surface (cutting surface) inclined. Traditionally, both surfaces might be treated similarly, but this inversion allows the pickup surface to be optimized for suction contact while the cutting surface maintains its inclined geometry for manufacturing efficiency.

Inventive Principle:

Principle #13The other way round (Inversion)

2Strength

If the side surface has a large angle with respect to the normal, then the structural integrity is maintained, but the pickup nozzle suction is obstructed

Engineering Contradiction:

Improvestructural integrityVSAvoidpickup operation

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent applies local quality by creating different surface characteristics in different regions of the SiC semiconductor layer. The front surface maintains the inclined surface for efficient cutting, while the back surface is designed to be substantially flat to enable reliable pickup. This localized differentiation allows each surface to optimize its function without compromising the other.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent inverts the conventional approach by making the back surface (pickup surface) flat while keeping the front surface (cutting surface) inclined. Traditionally, both surfaces might be treated similarly, but this inversion allows the pickup surface to be optimized for suction contact while the cutting surface maintains its inclined geometry for manufacturing efficiency.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS12255227B2SiC semiconductor device

Publication Date: 2025.03.18 ROHM CO LTD

AI summary

An SiC semiconductor device includes an SiC semiconductor layer including an SiC monocrystal that is constituted of a hexagonal crystal and having a first main surface as a device surface facing a c-plane of the SiC monocrystal and has an off angle inclined with respect to the c-plane, a second main surface at a side opposite to the first main surface, and a side surface facing an a-plane of the SiC monocrystal and has an angle less than the off angle with respect to a normal to the first main surface when the normal is 0°.