Silicon Substrate Corrosion Protection via Silane Coupling Agent

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Solution Overview

Problem

Existing methods for producing liquid ejection heads with silicon substrates face issues with silicon corrosion when exposed to alkaline inks, leading to potential performance and image formation problems due to silicon dissolution, and adhesion deterioration between metal oxide protective layers and organic resin layers.

Innovation Solution

A method involving the formation of a metal oxide protective layer on silicon substrates, followed by the removal of this layer in specific regions and the application of an organic resin layer, ensuring high adhesion and preventing peeling, with the organic resin layer extending over penetration ports and maintaining contact with the substrate to prevent corrosion and ink elution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal oxide protective layer is formed on the silicon substrate to prevent corrosion, then silicon corrosion resistance is improved, but adhesion between the protective layer and organic resin layer deteriorates causing peeling

Engineering Contradiction:

Improvesilicon corrosion resistanceVSAvoidadhesion between protective layer and organic resin layer

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

A silane coupling agent layer is introduced as an intermediary between the metal oxide protective layer and the organic resin layer. This coupling agent contains both inorganic bonding groups that bond to the metal oxide and organic bonding groups that bond to the resin, thereby mediating the adhesion interface and preventing peeling while maintaining corrosion protection

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The structure employs a composite material system consisting of metal oxide particles embedded in a silane coupling agent matrix, which is then bonded to the organic resin layer. This composite structure combines the corrosion resistance of metal oxide with the adhesion properties of the silane-resin interface

Inventive Principle:

Principle #40Composite materials

2Strength

If the organic resin layer is applied directly on the metal oxide protective layer, then adhesion is improved, but silicon corrosion resistance deteriorates due to ink elution

Engineering Contradiction:

Improveadhesion of organic resin layerVSAvoidsilicon corrosion resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The silane coupling agent serves as an intermediary layer that allows the organic resin to bond effectively while preventing direct contact between the corrosive ink and the metal oxide protective layer, thus maintaining both adhesion and corrosion resistance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The silane coupling agent layer provides localized chemical functionality at the interface, with inorganic groups oriented toward the metal oxide for bonding and organic groups oriented toward the resin for adhesion, creating a functionally differentiated interface structure

Inventive Principle:

Principle #3Local quality

3Strength

If the protective layer is removed completely to improve adhesion, then adhesion between layers is improved, but silicon corrosion resistance is lost

Engineering Contradiction:

Improveadhesion between layersVSAvoidsilicon corrosion resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Rather than complete removal, the protective layer is selectively modified by applying silane coupling agent in specific regions, creating local adhesion enhancement zones while preserving the metal oxide protective layer in other regions to maintain corrosion resistance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The protective layer function is segmented into two parts: the metal oxide layer that provides corrosion resistance and the silane coupling agent layer that provides adhesion, allowing each function to be optimized independently

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 approach effectively protects silicon substrates from corrosion and prevents peeling of the organic resin layer, enhancing the reliability and longevity of liquid ejection heads by maintaining adhesion and preventing ink elution through the use of titanium oxide films and organic resin layers.

Implementation Method 1

a protective layer made from a metal oxide protecting silicon against corrosion

Methodology Applied

Scientific EffectPhysical barrier protection:

Implementation Method 2

ensuring high adhesion and preventing peeling

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11168397B2Method for producing substrate, substrate, and liquid ejection head

Publication Date: 2021.11.09 CANON KK

AI summary

A method for producing a substrate that includes a protective layer made from a metal oxide protecting silicon against corrosion and an organic resin layer on a substrate surface of a silicon substrate includes the following steps in this order: step A of forming the protective layer on the substrate surface; step B of removing the protective layer from the substrate surface in a region Z1 that is a part of the region in which the protective layer has been formed; and step C of providing an organic resin layer on the substrate surface in a region Z2 including the region Z1.