Fuse Attenuation Members for Laser Damage Control

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Solution Overview

Problem

The method of disconnecting fuse elements by irradiating a laser beam faces challenges in maintaining reliability and minimizing damage to adjacent elements and the semiconductor substrate, particularly when the layout pitch is reduced, as it can lead to increased risk of damaging lower-layer wirings and through-hole electrodes.

Innovation Solution

Incorporating attenuation members, such as columnar bodies, between fuse elements that can absorb and scatter the laser beam energy, reducing its impact on adjacent elements and the substrate, allowing for a narrower layout pitch while ensuring reliability by using optical lenses to create focused and attenuated beam spots.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the layout pitch of fuse elements is reduced to increase memory density, then the number of fuse elements per unit area increases, but the risk of damaging adjacent fuse elements and lower-layer wirings by laser beam irradiation increases

Engineering Contradiction:

Improvenumber of fuse elements per unit areaVSAvoidrisk of damaging adjacent elements

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

An attenuation member is introduced as an intermediary element positioned between the fuse element and adjacent structures. This attenuation member absorbs and scatters the laser beam energy, preventing direct damage to adjacent fuse elements and lower-layer wirings while allowing the fuse element itself to be properly disconnected. This mediator enables tighter spacing without compromising reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The attenuation member is strategically positioned only in specific locations where laser beam scattering could damage adjacent structures, rather than uniformly across the entire device. This localized approach allows tight spacing in critical areas while maintaining manufacturing simplicity elsewhere.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If the layout pitch of fuse elements is reduced, then chip area utilization improves, but the beam spot of the laser beam becomes larger relative to the spacing, increasing damage risk

Engineering Contradiction:

Improvechip area utilizationVSAvoidlaser beam spread damage

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The attenuation member serves as a protective intermediary that intercepts and attenuates the scattered laser beam energy before it can reach adjacent fuse elements. By positioning this mediator in the path of scattered beams, the system can achieve tighter spacing without increasing damage risk from beam spread.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If attenuation members are added between fuse elements, then reliability against laser damage improves, but device complexity and manufacturing steps increase

Engineering Contradiction:

Improveprotection against laser damageVSAvoidnumber of structural elements

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The attenuation member is integrated with existing device structures such as insulation films or support layers, rather than being added as a completely separate component. This merging approach provides laser protection functionality while minimizing increases in overall device complexity and manufacturing steps.

Inventive Principle:

Principle #5Merging (Combining)

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 use of attenuation members effectively reduces the energy impact on adjacent fuse elements and their peripheries, enabling a tighter layout of fuse elements without compromising reliability, thereby minimizing damage to lower-layer wirings and the semiconductor substrate.

Implementation Method 1

attenuation members, such as columnar bodies, between fuse elements that can absorb and scatter the laser beam energy

Methodology Applied

Scientific EffectAbsorption: Absorption (EM radiation)

Implementation Method 2

attenuation members, such as columnar bodies, between fuse elements that can absorb and scatter the laser beam energy

Methodology Applied

Scientific EffectScattering: Scattering

Implementation Method 3

using optical lenses to create focused and attenuated beam spots

Methodology Applied

Scientific EffectFocusing: Focusing

Implementation Method 4

disconnecting a fuse element by breaking the fuse element by irradiating a laser beam

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 5

disconnecting a fuse element by fusing the fuse element using a large current

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS7868417B2Semiconductor device including a plurality of fuse elements and attenuation members between or around the plurality of fuse elements

Publication Date: 2011.01.11 MICRON TECHNOLOGY INC

AI summary

A semiconductor device includes plural fuse elements which can be disconnected by irradiating a laser beam, and attenuation members which are located between the plural fuse elements as viewed two-dimensionally and can attenuate the laser beam. Each attenuation member includes plural columnar bodies. With this arrangement, the attenuation members including plural columnar units absorb the laser beam leaked out from a fuse element to be disconnected to a semiconductor substrate side. The laser beam is also scattered by Fresnel diffraction. Therefore, the columnar body can efficiently attenuate the laser beam, without generating a crack in the insulation film by absorbing excessive energy.