Piezoelectric Element Manufacturing Sequence

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Solution Overview

Problem

The existing methods for manufacturing piezoelectric elements using non-lead-based materials, such as potassium sodium niobate (KNN), face challenges with crystal orientation deterioration and the generation of cracks and voids due to etching processing, which affects the performance and reliability of these elements in devices like ink jet recording heads and ultrasonic sensors.

Innovation Solution

A method involving the formation of a first piezoelectric layer before patterning the electrode, followed by the deposition of a second piezoelectric layer, which covers the first layer and substrate, to prevent crystal orientation deterioration and ensure better film quality, using a chemical solution method for improved crystal orientation and adhesion layer management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the piezoelectric layer is formed at the lower electrode patterned by etching processing, then the electrode pattern can be formed, but crystal orientation of the piezoelectric layer is deteriorated and cracks and voids are generated

Engineering Contradiction:

Improveelectrode patternVSAvoidcrystal orientation

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The lower electrode is patterned by etching processing before forming the piezoelectric layer. This preliminary patterning action allows the electrode pattern to be established first, and then the piezoelectric layer is formed over this patterned electrode, avoiding the need to pattern the piezoelectric layer itself and preventing crystal orientation deterioration

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of the conventional approach of forming the piezoelectric layer first and then patterning it, this invention inverts the sequence by patterning the electrode first and then forming the piezoelectric layer. This reversal eliminates the harmful effects of etching on the piezoelectric layer's crystal orientation while still achieving the desired electrode pattern

Inventive Principle:

Principle #13The other way round (Inversion)

2Shape

If the piezoelectric layer is formed at the lower electrode patterned by etching processing, then the electrode pattern can be formed, but cracks and voids are generated

Engineering Contradiction:

Improveelectrode patternVSAvoidcracks and voids

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The etching processing, which is potentially harmful to the piezoelectric layer, is performed beforehand on the electrode only. This converts the harmful effect into a beneficial sequence where the electrode can be precisely patterned without risking damage to the piezoelectric layer, which is formed afterward in its intact state

Inventive Principle:

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

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 approach prevents the deterioration of crystal orientation and reduces the occurrence of cracks and voids, resulting in a piezoelectric element with enhanced performance and reliability, suitable for various electronic devices requiring precise electromechanical conversion.

Implementation Method 1

using a chemical solution method for improved crystal orientation and adhesion layer management

Methodology Applied

Scientific EffectChemical solution method: Chemical Beam Epitaxy

Data Source

PatentUS20230354709A1Method Of Manufacturing Piezoelectric Element

Publication Date: 2023.11.02 SEIKO EPSON CORP

AI summary

A method of manufacturing a piezoelectric element of the present disclosure includes: a first film forming step of forming a first electrode at a substrate; a second film forming step of forming a first piezoelectric layer at the first electrode; a first processing step of patterning the first electrode and the first piezoelectric layer by etching; and a third film forming step of forming, after the first processing step, a second piezoelectric layer to cover the first electrode, the first piezoelectric layer, and the substrate.