Wafer Shield Tunnel Sequencing to Suppress Division Cracks

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Solution Overview

Problem

Cracks develop outside planned dividing lines during wafer division due to the crystal structure of the material, causing damage to devices when using laser beam irradiation.

Innovation Solution

A wafer processing method involving shield tunnel formation with alternating laser beam irradiation and external force application to suppress crack development, using laser beams with transmissibility and forming shield tunnels with fine pores and modified tubes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If laser beam irradiation is used to divide wafer, then processing efficiency is improved, but cracks develop outside planned dividing lines causing device damage

Engineering Contradiction:

Improveprocessing efficiencyVSAvoiddevice integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the continuous laser beam irradiation into discrete, spaced-apart irradiation points along the dividing line. By forming shield tunnels at intervals rather than continuous irradiation, the laser energy is distributed in controlled segments that prevent heat accumulation and crack propagation to adjacent devices, thus maintaining processing efficiency while protecting device integrity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by creating shield tunnels with specific structural characteristics (fine pores and modified tubes) at precise locations along the dividing line. The laser irradiation is localized to specific points with controlled spacing, creating localized modifications that provide mechanical separation without affecting adjacent device regions, thereby preventing cracks from spreading to neighboring devices

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If laser beam with transmissibility is used to form shield tunnels, then internal modified layer is created, but crack propagation to outside regions occurs

Engineering Contradiction:

Improveshield tunnel formation precisionVSAvoidcrack propagation

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by forming shield tunnels with fine pores and modified tubes along the planned dividing line before the final wafer separation step. These pre-formed shield structures create a mechanical barrier that guides crack propagation along the intended dividing line and prevents cracks from deviating to adjacent device regions, thereby enhancing manufacturing precision while suppressing harmful crack propagation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The shield tunnel structure acts as an intermediary element between the laser irradiation and the wafer bulk material. The fine pores and modified tubes within the shield tunnel serve as a mediator that absorbs and redirects stress, preventing direct crack propagation from the irradiation zone to adjacent device regions while maintaining the integrity of the created dividing line

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Suppresses crack formation outside planned dividing lines and prevents device damage by alternating laser beam irradiation and external force application, effectively dividing wafers into individual device chips.

Implementation Method 1

a shield tunnel forming step of executing irradiation with a laser beam with a wavelength having transmissibility with respect to the wafer to form shield tunnels each including a fine pore and a modified tube that surrounds the fine pore

Methodology Applied

Scientific EffectLaser beam irradiation with transmissibility: Laser

Implementation Method 2

a type that executes irradiation with a laser beam with a wavelength having transmissibility with respect to a wafer to execute internal processing by which a modified layer is formed inside the wafer

Methodology Applied

Scientific EffectLight transmission through transparent material: Absorption (EM radiation)

Implementation Method 3

a dividing step of applying an external force to the wafer to divide the wafer into the individual device chips after executing the shield tunnel forming step

Methodology Applied

Scientific EffectMechanical force application: Mechanical Force

Data Source

PatentUS12482708B2Wafer processing method

Publication Date: 2025.11.25 DISCO CORP

AI summary

A wafer processing method includes a shield tunnel forming step of executing irradiation with a laser beam with a wavelength having transmissibility with respect to a wafer to form shield tunnels each including a fine pore and a modified tube that surrounds the fine pore, and a dividing step of applying an external force to the wafer to divide the wafer into individual device chips. The shield tunnel forming step includes a first shield tunnel forming step of successively forming the shield tunnels in one planned dividing line with interposition of at least intervals corresponding to one shield tunnel, and a second shield tunnel forming step of successively forming the shield tunnels in regions in which the intervals are provided in the planned dividing line.