Hydrogen Barrier Liner for FRAM Chip PZT Protection

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Solution Overview

Problem

Hydrogen reacts with PZT material in FRAM chip manufacturing processes, leading to deterioration, and existing methods fail to effectively reduce exposure during hydrogen-bearing deposition and etch processes.

Innovation Solution

A hydrogen barrier liner is introduced, comprising specific layers such as iridium oxide, titanium, and aluminum oxide, which are deposited over the dielectric layers and trench structures to prevent hydrogen from reaching the PZT material, along with a silicon dioxide plug to fill trenches and protect the gate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If hydrogen bearing deposition and etch processes are used in FRAM chip manufacturing, then manufacturing productivity is improved, but PZT material deteriorates due to hydrogen reaction

Engineering Contradiction:

Improvemanufacturing productivityVSAvoidPZT material stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A hydrogen barrier liner is introduced as an intermediary layer between the hydrogen bearing processes and the PZT material. The liner acts as a mediator that allows the deposition and etch processes to proceed while preventing hydrogen from reaching and reacting with the PZT material, thus resolving the contradiction between manufacturing productivity and material stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the harmful effect of hydrogen by using it to form a protective hydrogen barrier liner through controlled reaction. The hydrogen that would otherwise damage the PZT material is instead utilized to create a protective layer, transforming the harmful factor into a beneficial protective mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Reliability

If etching vias for metallurgy connections is performed, then electrical connectivity is achieved, but hydrogen pathways are created to PZT material

Engineering Contradiction:

Improveelectrical connectivityVSAvoidhydrogen exposure to PZT

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The hydrogen barrier liner is applied locally at the trench walls where hydrogen exposure is most critical, while allowing the via to maintain its electrical connectivity function. This localized protection approach ensures that the harmful hydrogen exposure is prevented at the interface with PZT material while preserving the necessary electrical pathways.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

A thin film hydrogen barrier liner is deposited to line the trenches, creating a flexible yet effective barrier that conforms to the trench geometry. This thin film structure provides hydrogen protection while maintaining the structural integrity and electrical functionality of the via connections.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If multiple protective layers are deposited to prevent hydrogen exposure, then PZT material protection is improved, but device complexity increases

Engineering Contradiction:

ImprovePZT material protectionVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The hydrogen barrier liner is formed as a composite structure with multiple layers including iridium oxide, titanium, and aluminum oxide. This composite material approach provides enhanced hydrogen barrier properties while maintaining a manageable structural complexity through the integration of these layers into a unified protective system.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The protective barrier is segmented into multiple functional layers, each with specific properties: iridium oxide for hydrogen barrier, titanium for adhesion, and aluminum oxide for additional protection. This segmentation allows each layer to perform its specific function optimally while collectively providing comprehensive protection.

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 hydrogen barrier effectively reduces the deterioration of PZT material by minimizing hydrogen exposure, enhancing the stability and reliability of FRAM chips during processing.

Implementation Method 1

Methodology Applied

Scientific EffectPhysical barrier: Physical Containment

Implementation Method 2

A hydrogen barrier liner is introduced, comprising specific layers such as iridium oxide, titanium, and aluminum oxide, which are deposited over the dielectric layers and trench structures

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS8658435B2Hydrogen barrier liner for ferro-electric random access memory (FRAM) chip

Publication Date: 2014.02.25 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method for forming a hydrogen barrier liner for a ferro-electric random access memory chip including forming a first dielectric layer over a substrate; forming a gate over the first dielectric layer; forming a first aluminum oxide layer over the gate and the first dielectric layer; forming a second dielectric layer over the first aluminum oxide layer; etching a trench through the second dielectric layer and the first aluminum oxide layer to the gate; forming a hydrogen barrier liner over the second dielectric layer, the hydrogen barrier liner lining the trench and contacting the gate; forming a silicon dioxide layer over the first aluminum dioxide layer, the silicon dioxide layer substantially filling the trench; and substantially removing the silicon dioxide layer leaving a silicon dioxide plug in the trench.