Semiconductor Protection Layer for Laser Fuse Blowing Damage

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Solution Overview

Problem

The laser-based fuse blowing process in semiconductor ICs often causes damage to the substrate and gate dielectric layers due to excess energy, leading to inefficiencies in packaging density and performance limitations, as conventional protection methods are either ineffective or impractical for submicron geometries.

Innovation Solution

A semiconductor structure featuring a protection layer and seal ring constructed on metal layers between the fuse and the substrate, which confines and shields the energy, incorporating a protection diode with a larger thermal reservoir to dissipate excess energy and prevent damage, while allowing for circuitry construction beneath the fuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a laser beam is used to blow fuses, then the circuit configuration can be modified, but significant laser energy penetrates lower layers causing damage to the substrate and gate dielectric layers

Engineering Contradiction:

Improvecircuit configuration modificationVSAvoidlaser energy damage to substrate and gate dielectric

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A protection layer is introduced as an intermediary element between the fuse and the gate dielectric layer. This protection layer absorbs and dissipates excess laser energy, preventing it from reaching and damaging the gate dielectric layer and substrate. The protection layer acts as a mediator that intercepts the harmful laser energy before it can cause damage to underlying structures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protection layer is positioned and prepared in advance before the laser blow process occurs. By having the protection layer already in place, the system preemptively addresses the potential damage issue. The protection layer is designed with specific material properties and thickness to ensure it can handle the expected laser energy exposure during fuse blowing operations.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If no electronic devices or circuits are placed beneath the fuse, then substrate damage during laser blow is avoided, but packaging density decreases due to unused substrate areas

Engineering Contradiction:

Improvesubstrate protection from laser damageVSAvoidpackaging density

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The protection layer serves as an intermediary shield that enables the placement of electronic devices and circuits beneath the fuse. By absorbing excess laser energy, the protection layer creates a safe zone underneath the fuse, allowing substrate utilization without compromising device reliability. This resolves the contradiction by enabling both high packaging density and substrate protection simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If thick gate dielectric layers are used, then gate dielectric layer damage from laser energy is reduced, but size and performance limitations occur in submicron geometry ICs

Engineering Contradiction:

Improvegate dielectric layer protectionVSAvoidgate dielectric layer thickness

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The protection layer acts as an external intermediary shield that protects the gate dielectric layer from laser damage, eliminating the need to increase gate dielectric thickness. This approach allows submicron geometry ICs to maintain their thin gate dielectric layers for optimal performance while still providing robust protection against laser-induced damage through the dedicated protection layer.

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

This solution effectively protects the substrate and gate dielectric layers from laser-induced damage, increasing layout area utilization and preventing cracks, thermal shrinkage, and burnout, while enabling more efficient use of IC space and improved thermal dissipation.

Implementation Method 1

The protection layer is formed within the seal ring, on at least one metal layer between the device and the fuse for shielding the device from being directly exposed to the energy

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

The seal ring, which surrounds the fuse, is constructed on at least one metal layer between the device and the fuse for confining the energy therein

Methodology Applied

Scientific EffectConfinement: Physical Containment

Implementation Method 3

The protection diode dissipates excess energy before it is applied to the gate dielectric layer of a device close to the fuse

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8242576B2Protection layer for preventing laser damage on semiconductor devices

Publication Date: 2012.08.14 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor structure prevents energy that is used to blow a fuse from causing damage. The semiconductor structure includes a device, guard ring, and at least one protection layer. The device is constructed on the semiconductor substrate underneath the fuse. The seal ring, which surrounds the fuse, is constructed on at least one metal layer between the device and the fuse for confining the energy therein. The protection layer is formed within the seal ring, on at least one metal layer between the device and the fuse for shielding the device from being directly exposed to the energy.