Semiconductor Fuse With Segmented Contact Structure

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Solution Overview

Problem

Conventional semiconductor device fuses are prone to oxidation, damage, and electrical shorts due to metal line migration, making it difficult to reduce fuse size without affecting neighboring fuses and compromising device reliability.

Innovation Solution

A semiconductor device fuse structure featuring a first and second metal line with a dummy line in between, and contact fuses with overlapping upper portions and spaced lower portions, formed using materials like tungsten, titanium, or copper, which can be easily cut by a laser spot without damaging adjacent fuses, and a method for forming these fuses that includes forming metal contact holes and filling them with metal material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a line-type metal fuse is used, then the fuse can be formed with simple structure, but the area occupied by the fuse becomes large

Engineering Contradiction:

Improvefuse structureVSAvoidfuse area

Core Design Contradiction:

Device complexityVSArea of stationary object

Solution Approach 1:

The fuse is divided into multiple segments (first fuse, second fuse, third fuse) arranged in a U-shape pattern rather than a single continuous line. This segmentation allows the fuse to occupy less area while maintaining its functionality for laser cutting and electrical connection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fuse structure is nested within a fuse box, with the U-shaped fuse pattern contained within the fuse box boundaries. This nesting arrangement optimizes space utilization and reduces the overall area occupied by the fuse structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Area of stationary object

If the fuse length is shortened to reduce area, then the area occupied by the fuse decreases, but neighboring fuses are likely to be damaged during cutting

Engineering Contradiction:

Improvefuse areaVSAvoidfuse cutting reliability

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The fuse structure incorporates a dummy line portion that has different properties from the functional fuse portions. The dummy line provides spacing and isolation between adjacent fuses, ensuring that when one fuse is cut by laser, the neighboring fuses are not affected. This local differentiation maintains cutting reliability while reducing overall area.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The dummy line acts as an intermediary element between adjacent functional fuses. It provides a buffer zone that prevents laser cutting of one fuse from damaging neighboring fuses, thereby maintaining reliability in a compact area.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If aluminum is used for the fuse, then the fuse can be formed easily, but the fuse is vulnerable to oxidation and shows poor contact characteristic

Engineering Contradiction:

Improvefuse formationVSAvoidcontact characteristic

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The fuse structure uses a composite material approach by combining multiple metal layers (first metal line, second metal line, dummy line) with different properties. This composite structure provides both ease of formation and improved contact characteristics while reducing oxidation vulnerability through the multi-layer design.

Inventive Principle:

Principle #40Composite materials

4Reliability

If Cu is used for the fuse and damascene process is applied, then the fuse can be formed with good contact characteristic, but Cu tends to migrate into another device element causing electrical short

Engineering Contradiction:

Improvecontact characteristicVSAvoidmetal migration

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The fuse is segmented into multiple portions (first fuse, second fuse, third fuse) with the dummy line portion providing isolation. This segmentation prevents copper migration from affecting adjacent device elements, as the dummy line acts as a barrier that stops the migration path while maintaining good contact characteristics in the functional fuse portions.

Inventive Principle:

Principle #1Segmentation

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 solution allows for a smaller fuse size with improved reliability, reduced oxidation, and minimized risk of damaging neighboring fuses during cutting, enhancing production efficiency and reducing production costs.

Implementation Method 1

a fuse is used... the fuses can be blown (or severed) by a laser spot

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS8860175B2Fuse of semiconductor device and method for forming the same

Publication Date: 2014.10.14 SK HYNIX INC

AI summary

A fuse of a semiconductor device and a method for forming the same are disclosed. The fuse includes a first metal line formed over a semiconductor substrate, a second metal line spaced apart from the first metal line, and a contact fuses formed of a metal contact coupled to the first metal line and the second metal line. Upper parts of the contact fuses overlap with each other, and lower parts are spaced apart from each other. Since the fuse is formed of a metal contact, fuse oxidation and fuse movement can be prevented. A conventional metal-contact fabrication process can be used, so that mass production of semiconductor devices is possible. In addition, the fuse region is reduced in size, reducing production costs.