Semiconductor Laser Cutting With Two-Density Modified Spots

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Solution Overview

Problem

The existing methods for forming modified regions in semiconductor objects to facilitate fracture formation during laser processing are not precise enough, leading to unsuitable semiconductor members due to inconsistent and unpredictable fracture widths.

Innovation Solution

A laser processing method involving the formation of first and second modified spots along a virtual plane with varying formation densities, where the second spots have a higher density and are connected, to control fracture extension perpendicular to the plane, ensuring high precision in fracture formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single-step laser processing method is used to form modified regions, then the process is simple and fast, but the fracture width is inconsistent and unpredictable

Engineering Contradiction:

Improveprocessing speedVSAvoidfracture width consistency

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The laser processing is divided into two distinct steps: a first step forming modified regions at a first formation density, and a second step forming modified regions at a second formation density. This segmentation allows each step to contribute differently to the final fracture characteristics, achieving both efficiency and precision that a single step cannot provide.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the formation density parameter between two processing steps. The first step uses a first formation density to create initial modified regions, while the second step uses a second formation density (different from the first) to create additional modified regions. This parameter variation enables control over fracture width and consistency while maintaining processing efficiency.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If laser light enters from the surface to form modified regions, then the process is straightforward, but the fracture extension perpendicular to the virtual plane cannot be suppressed

Engineering Contradiction:

Improveprocess simplicityVSAvoidfracture alignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention applies different formation densities at different stages of the process. The first formation density creates initial modified regions with certain characteristics, while the second formation density creates additional modified regions that specifically suppress fracture extension perpendicular to the virtual plane. This local differentiation of quality achieves precise fracture control.

Inventive Principle:

Principle #3Local quality

3Loss of time

If modified regions are formed with low formation density, then the processing time is short, but the fractures are not connected and precision is reduced

Engineering Contradiction:

Improveprocessing timeVSAvoidfracture connection precision

Core Design Contradiction:

Loss of timeVSManufacturing precision

Solution Approach 1:

The first step performs a preliminary action by forming modified regions at a first formation density, creating initial fracture pathways. The second step then builds upon this foundation by forming additional modified regions at a second formation density, ensuring fracture connection and precision. This preliminary action approach divides the work into manageable stages.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The two-step process maintains continuity of useful action by having the second step follow the first step without interruption. The modified regions formed in the first step serve as a foundation for the second step, creating a continuous process that achieves both efficiency and precision through sequential, complementary actions.

Inventive Principle:

Principle #20Continuity of useful action

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 enables the production of suitable semiconductor members by accurately forming fractures across virtual planes, allowing for precise cutting and acquisition of high-quality semiconductor wafers or devices.

Implementation Method 1

causing laser light to enter into the semiconductor object from the surface

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

forming a plurality of first modified spots along the virtual plane to obtain first formation density

Methodology Applied

Scientific EffectPhotothermal effect: Absorption (EM radiation)

Data Source

PatentUS12472587B2Laser processing method, semiconductor member manufacturing method, and laser processing device

Publication Date: 2025.11.18 HAMAMATSU PHOTONICS KK

AI summary

There is provided a laser processing method for cutting a semiconductor object along a virtual plane facing a surface of the semiconductor object in the semiconductor object. The laser processing method includes a first step of forming a plurality of first modified spots along the virtual plane to obtain first formation density, by causing laser light to enter into the semiconductor object from the surface, and a second step of forming a plurality of second modified spots along the virtual plane so as to obtain second formation density higher than the first formation density, by causing laser light to enter into the semiconductor object from the surface after the first step.