Light Emitting Wafer Separation Using Two-Step Laser Embrittlement

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Solution Overview

Problem

Current methods for manufacturing light emitting elements face inefficiencies in production, particularly due to unintended splits and damage during laser irradiation steps, which reduce yield and hinder increased production efficiency.

Innovation Solution

A light emitting element manufacturing method involving controlled laser beam irradiation with specific pitch and direction settings to generate embrittled regions within the substrate, allowing precise separation and minimizing unintended splits, using a combination of first and second irradiation steps with adjusted laser parameters to optimize substrate separation and reduce damage to the semiconductor structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser beam irradiation is performed to separate light emitting elements, then element separation is achieved, but unintended splits and damage to semiconductor structure occur

Engineering Contradiction:
Improveelement separation precisionVSAvoidunintended splits and damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The laser irradiation process is divided into two distinct steps: first forming embrittled regions along separation lines, then inducing controlled cracks at specific locations. This segmentation of the separation process allows precise control over where cracks form, preventing unintended splits while achieving clean element separation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Embrittled regions are formed in advance along the desired separation lines through first laser irradiation. This preliminary action creates predetermined weak zones that guide subsequent crack formation, ensuring cracks occur only at intended locations and not randomly throughout the substrate.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If conventional laser dicing method is used, then element separation is achieved, but production efficiency is insufficient

Engineering Contradiction:
Improveelement separationVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The laser beam irradiates multiple elements continuously along a line without stopping between elements. This continuous irradiation approach eliminates repeated positioning and setup operations, significantly improving production efficiency while maintaining precise separation through the embrittled region formation mechanism.

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If laser beam is focused to form embrittled regions, then separation lines are created, but crack control becomes difficult

Engineering Contradiction:
Improveseparation line formationVSAvoidcrack formation control
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

Different regions of the substrate receive different treatments: embrittled regions are formed along separation lines through focused laser irradiation, while crack initiation points are created at specific local positions. This local differentiation allows precise control over both separation line formation and crack location, preventing unintended splits.

Inventive Principle:
Principle #3Local quality

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 method enhances production efficiency by reducing unintended splits, increasing breaking strength, and ensuring stable irradiation conditions, leading to higher quality light emitting elements with improved yield and reduced damage to the semiconductor structure.

Implementation Method 1

irradiating a laser beam along first lines L1 to generate a plurality of embrittled regions 53a inside the substrate 50

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

irradiating a laser beam along second lines L2 different from the first lines L1, and having a light collecting point inside of the substrate 50, thereby generating a plurality of embrittled regions 53b inside the substrate 50

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3453481B1Method of manufacturing a light emitting element
Publication Date: 2023.09.06 NICHIA CORP
  • EP3453481B1 patent drawingFigure 1~2
  • EP3453481B1 patent drawingFigure 3~4
  • EP3453481B1 patent drawingFigure 5~6

AI summary

A method of manufacturing a light emitting element includes. providing a wafer including: a substrate, and a semiconductor structure; irradiating the substrate with a laser beam to form a plurality of modified regions in the substrate; and subsequently, separating the wafer into a plurality of light emitting elements. Irradiating the substrate with a laser beam includes: performing a first irradiation step comprising irradiating the laser beam along a plurality of first lines that extend in a first direction that is parallel to the first face and that are aligned in a second direction that is parallel to the first face and intersects the first direction, and subsequent to performing the first irradiation step, performing a second irradiation step comprising irradiating the laser beam along second lines that extend in the second direction.