GaN Wafer Laser Separation for Low-Kerf Slicing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing methods for manufacturing wafers from gallium nitride ingots result in a high kerf loss due to the use of cutting blades, making the process uneconomical.

Innovation Solution

A manufacturing method that involves forming a separation layer in the workpiece using a pulsed laser beam, allowing for the wafer to be separated from the ingot with reduced kerf loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If a cutting blade is used to slice the GaN ingot, then the wafer can be separated from the ingot, but the kerf loss becomes comparatively high (60% to 70% of the ingot thickness)

Engineering Contradiction:

Improvekerf lossVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Loss of substanceVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical cutting blade system with a laser-based system. A pulsed laser beam is used to form a separation layer within the GaN ingot by irradiating it from the first surface, causing internal modification at the focal point. This optical method eliminates the need for physical contact with a cutting blade, thereby reducing kerf loss significantly while maintaining manufacturing feasibility

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and properties of the GaN material through laser irradiation. By controlling the laser parameters (wavelength, pulse duration, focal depth, scanning speed), the material undergoes internal modification to form a separation layer with different properties than the bulk material. This allows separation without mechanical removal of large portions of the ingot

Inventive Principle:

Principle #35Parameter changes

2Loss of substance

If a thick cutting blade is used for slicing, then the structural integrity of the blade is maintained, but the kerf loss increases significantly

Engineering Contradiction:

Improvekerf lossVSAvoidblade structural integrity

Core Design Contradiction:

Loss of substanceVSStrength

Solution Approach 1:

The mechanical cutting blade is completely replaced by a laser beam system. The laser provides sufficient energy density to modify the GaN material internally without requiring physical thickness for structural integrity. The focal point of the laser can be precisely controlled to create the separation layer at the desired depth, eliminating the trade-off between blade thickness and kerf loss

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If the focal point is positioned at a predetermined depth position in the workpiece, then the separation layer is formed precisely, but the laser beam must transmit through the workpiece surface

Engineering Contradiction:

Improveseparation layer position precisionVSAvoidlaser beam energy transmission

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent selects a laser wavelength that optimally balances transmission through the GaN surface and absorption at the focal point. The wavelength is chosen so that the laser beam can penetrate the first surface with minimal loss while the focused energy at the predetermined depth position is sufficiently absorbed to create the separation layer. This parameter optimization enables precise positioning without excessive energy loss

Inventive Principle:

Principle #35Parameter changes

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

The method significantly reduces kerf loss and improves productivity by allowing for the precise separation of wafers from ingots using a laser-based process.

Implementation Method 1

forming a separation layer in the workpiece by relatively moving, along a predetermined direction, the workpiece and a focal point of a pulsed laser beam having such a wavelength as to be transmitted through the workpiece

Methodology Applied

Scientific EffectLaser beam irradiation: Laser

Implementation Method 2

the focal point is positioned at a predetermined depth position in the workpiece... in which the first surface is irradiated with the laser beam

Methodology Applied

Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 3

a holding step of sucking and holding the second surface of the workpiece

Methodology Applied

Scientific EffectVacuum suction: Suction

Data Source

PatentUS20250187230A1Manufacturing method of wafer

Publication Date: 2025.06.12 DISCO CORP

AI summary

There is provided a manufacturing method of a wafer for manufacturing from a workpiece the wafer having a thickness smaller than the distance between a first surface and a second surface of the workpiece. The workpiece is an ingot of GaN or a single-crystal substrate of GaN. The method includes forming a separation layer in the workpiece by relatively moving, along a predetermined direction, the workpiece and the focal point of a pulsed laser beam transmitting through the workpiece in a state in which the first surface is irradiated with the laser beam and the focal point is positioned at a predetermined depth position in the workpiece, and separating the wafer from the workpiece by using the separation layer as the point of origin. The angle between a crystal orientation represented by <1010> and the predetermined direction in a (0001) plane is equal to or smaller than 10°.