Laser-Formed Protective Wall for Crack-Free Wafer Separation

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Solution Overview

Problem

Existing methods for processing workpieces, such as wafers with integrated circuits, often result in cracks developing from unnecessary regions to necessary regions due to laser irradiation or cutting, causing damage to the necessary regions.

Innovation Solution

A processing method involving the formation of protective walls using laser beams with transmissibility to the workpiece, creating shield tunnels composed of fine pores and modified tubes to prevent cracks, followed by removal of unnecessary regions using either laser processing or cutting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high power laser beam irradiation is applied to process planned dividing lines, then processing efficiency is improved, but cracks develop to necessary regions causing device damage

Engineering Contradiction:

Improveprocessing efficiencyVSAvoiddevice integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The laser processing is divided into two distinct stages: first forming shield tunnels at regular intervals along the dividing line, then removing material between these tunnels. This segmentation allows efficient bulk removal while the spaced tunnels prevent crack propagation to device regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Shield tunnels are formed in advance before final dividing line removal. These pre-formed tunnels act as barriers that prevent cracks from propagating to necessary regions during subsequent high-power laser irradiation or mechanical cutting operations.

Inventive Principle:

Principle #10Preliminary action

2Speed

If high power laser beam is used to remove unnecessary regions, then processing speed is improved, but cracks propagate from unnecessary to necessary regions

Engineering Contradiction:

Improveprocessing speedVSAvoidcrack propagation

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

Shield tunnels serve as intermediary structures positioned between the high-power laser processing zone and the necessary device regions. These tunnels absorb and redirect stress, preventing crack propagation while allowing rapid material removal in the unnecessary regions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The shield tunnels are formed beforehand to create a protective barrier that cushions against crack propagation. This preliminary protective structure allows subsequent high-speed processing without transmitting harmful stresses to the necessary regions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If mechanical cutting is used to divide wafers along planned dividing lines, then manufacturing precision is improved, but cracks still develop to device regions

Engineering Contradiction:

Improvecutting precisionVSAvoiddevice integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The protective wall consists of multiple discrete shield tunnels spaced at regular intervals rather than a continuous structure. This segmentation provides effective crack prevention while allowing precise mechanical cutting to proceed between the tunnel locations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The shield tunnels are strategically positioned at specific intervals along the dividing line where crack initiation is most likely, rather than providing uniform protection everywhere. This local quality approach prevents cracks at critical locations while maintaining cutting precision in other areas.

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

Prevents cracks from forming in necessary regions during the removal of unnecessary regions, ensuring the integrity of the devices or features on the workpiece.

Implementation Method 1

irradiating a region that defines a boundary between the necessary region and the unnecessary region with a laser beam having a wavelength that has transmissibility with respect to the workpiece

Methodology Applied

Scientific EffectLaser irradiation with transmissibility: Laser

Implementation Method 2

a type that executes irradiation with a laser beam with a wavelength having absorbability with respect to a wafer, to execute ablation processing

Methodology Applied

Scientific EffectAblation processing: Ablation

Implementation Method 3

forming a plurality of shield tunnels composed of a fine pore and a modified tube that surrounds the fine pore, thereby forming a protective wall

Methodology Applied

Scientific EffectPhysical containment through modified structure: Physical Containment

Data Source

PatentUS12494371B2Processing method

Publication Date: 2025.12.09 DISCO CORP

AI summary

There is provided a processing method of a workpiece including a necessary region and an unnecessary region. The processing method includes a protective wall forming step of irradiating a region that defines the boundary between the necessary region and the unnecessary region with a laser beam with a wavelength that has transmissibility with respect to the workpiece and forming a plurality of shield tunnels composed of a fine pore and a modified tube that surrounds the fine pore, thereby forming a protective wall, and an unnecessary region removal step of removing the unnecessary region after executing the protective wall forming step.