Stacked Metal Capacitor Electrode Structure for Corrosion Resistance

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Solution Overview

Problem

Existing electro-optical devices, such as liquid crystal projectors, face challenges in enlarging the capacitance of storage capacitors due to the intolerance of aluminum electrodes to hydrofluoric acid, which is used to remove reaction products from dry etching, leading to increased resistance and reduced capacitance values.

Innovation Solution

The design includes a lower capacitance electrode with a first metal film and a second metal film stacked on the substrate, where the first protective insulating film exposes the side wall of the second metal film, allowing for a larger capacitance area without exposing the aluminum, thus preventing corrosion and enabling the use of low-resistance materials like aluminum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the opening area of the insulating film is increased to enlarge the capacitance of the storage capacitor, then the capacitance value increases, but the aluminum of the first electrode is exposed to the drug solution containing hydrofluoric acid, causing corrosion and increased resistance

Engineering Contradiction:

Improvecapacitance valueVSAvoidintegrity of aluminum electrode

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The insulating film is segmented into two distinct parts: a first insulating film covering the first electrode and a second insulating film covering the second electrode. This segmentation allows the opening to expose only the second electrode while keeping the first electrode protected, enabling capacitance enlargement without aluminum corrosion

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first insulating film acts as an intermediary protective layer between the aluminum first electrode and the drug solution containing hydrofluoric acid. This intermediary prevents direct contact between the aluminum and the corrosive solution, allowing the opening area to be enlarged for capacitance enhancement without compromising the aluminum electrode

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If aluminum is used as the low resistance material for the capacitance line to reduce resistance, then the resistance decreases, but the aluminum shows weak tolerance to the drug solution containing hydrofluoric acid, leading to corrosion when the opening area is increased

Engineering Contradiction:

Improveresistance of capacitance lineVSAvoidcorrosion resistance to hydrofluoric acid

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The first insulating film serves as a protective intermediary that shields the aluminum first electrode from the corrosive drug solution. This allows aluminum to be used for its low resistance properties without direct exposure to hydrofluoric acid, preventing corrosion while maintaining electrical performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The insulating film structure is segmented into a first insulating film for protecting the aluminum electrode and a second insulating film for defining the capacitance structure. This segmentation enables the aluminum to be protected while still allowing the capacitance-enlarging opening to be formed

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

This configuration enhances the capacitance of the storage capacitor, improves potential retention properties, and allows for high-quality display in electronic devices by maintaining the integrity of the low-resistance material while increasing capacitance values.

Implementation Method 1

a first protective insulating film which covers a side wall of the first metal film, and exposes at least a portion of a side wall of the second metal film

Methodology Applied

Scientific EffectPhysical barrier protection:

Implementation Method 2

a dielectric film which is arranged throughout the side wall of the second metal film which is exposed from the first protective insulating film, and over the second metal film

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 3

a storage capacitor is formed between the first electrode, the dielectric layer, and the second electrode... potential retention properties of the image signal in the pixel electrode is enhanced

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9449997B2Electro-optical device, electronic apparatus, and method for manufacturing electro-optical device

Publication Date: 2016.09.20 138 EAST LCD ADVANCEMENTS LTD

AI summary

An electro-optical device includes an element substrate main body, a first capacitance electrode that is arranged above the element substrate main body, and has a first metal film and a second metal film which is stacked onto the first metal film, a first protective insulating film that is arranged so as to cover a side wall of the first metal film, and expose at least a portion of a side wall of the second metal film, a dielectric film that is arranged throughout the side wall of the second metal film which is exposed from the first protective insulating film, and over the second metal film, and a second capacitance electrode that is arranged throughout the dielectric film on the second metal film, and over the dielectric film which is arranged in the side wall of the second metal film exposed from the first protective insulating film.