Capacitor Insulating Layer Thickness Control for Piezoelectric Reliability

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Solution Overview

Problem

Existing piezoelectric devices face damage from excessive over-etching during the removal of the upper electrode layer, which can lead to short circuits and reliability issues in the capacitor ends defined by the second electrode layer.

Innovation Solution

The configuration includes an insulating layer that extends to a non-element region outside the capacitor, with a thickness difference of 50 nm or less between the insulating layer under the non-element region and under the capacitor, preventing excessive over-etching damage by carefully controlling the etching process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If over-etching is performed to completely remove the upper electrode layer, then short circuit prevention is improved, but damage to the piezoelectric layer and capacitor boundary occurs

Engineering Contradiction:

Improveshort circuit preventionVSAvoidcapacitor boundary integrity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The insulating layer is extended to the non-element region before the etching process begins. This preliminary structural preparation ensures that when over-etching occurs to remove the upper electrode layer, the extended insulating layer acts as a protective buffer that prevents the etching from reaching and damaging the piezoelectric layer and capacitor boundary, thus allowing complete electrode removal without compromising component integrity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The extended insulating layer in the non-element region serves as a cushioning layer that absorbs the excessive etching action. By having this additional insulating material in place beforehand, the harmful effects of over-etching are contained and prevented from propagating to the sensitive piezoelectric layer, thereby protecting the capacitor boundary while still achieving complete upper electrode layer removal

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 reliability of the capacitor and piezoelectric element by preventing damage during the etching process, resulting in improved manufacturing yield and device performance.

Implementation Method 1

the piezoelectric element that is provided in the piezoelectric device, which is a type of the electronic device, is used to eject (discharge) a variety of liquids from a liquid ejecting head

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS10573463B2Electronic device, piezoelectric device, liquid ejecting head, and manufacturing methods for electronic device, piezoelectric device, and liquid ejecting head

Publication Date: 2020.02.25 SEIKO EPSON CORP

AI summary

An electronic device includes a capacitor that is configured with a first electrode layer, an insulating layer, and a second electrode layer being formed in the order listed herein. At least one end of the capacitor is defined by an end of the second electrode layer. The insulating layer is provided so as to extend to a non-element region that is on the outside of one end of the capacitor. The insulating layer under the non-element region is formed thinner than the insulating layer under the capacitor. A difference between the thickness of the insulating layer under the non-element region and the thickness of the insulating layer under the capacitor is equal to or less than 50 nm.