Reverse-Tapered Bump Adhesion Layer for Ink Jet Recording Heads
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Solution Overview
Problem
The existing bump formation process for ink jet recording heads requires additional steps to form a protective film around the bump, increasing the total number of manufacturing steps and complexity.
Innovation Solution
A reverse-tapered bump shape is created with a larger upper surface area than the lower surface area, where the side face of the bump is covered with a polyether amide resin adhesion layer that serves as both an adhesion layer and a protective film, eliminating the need for additional steps in the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective film is formed around the bump using the known method, then the bump is protected from side etching and corrosion, but the total number of manufacturing steps increases
Solution Approach 1:
The adhesion layer and protective film are merged into a single layer. The adhesion layer is formed to cover the side surface of the bump, and it simultaneously serves as the protective film, eliminating the need for a separate protective film layer and reducing the total number of manufacturing steps.
Solution Approach 2:
The adhesion layer is given dual functionality: it provides adhesion between the bump and the surrounding structure, and it also serves as the protective film that prevents side etching and corrosion. This multi-functionality resolves the contradiction by eliminating the need for an additional protective film layer.
2Reliability
If additional manufacturing steps are added to form a protective film, then bump protection is improved, but manufacturing efficiency decreases
Solution Approach 1:
The adhesion layer and protective film are merged into a single layer. The adhesion layer is formed to cover the side surface of the bump, and it simultaneously serves as the protective film, eliminating the need for a separate protective film layer and reducing the total number of manufacturing steps.
Solution Approach 2:
The adhesion layer is given dual functionality: it provides adhesion between the bump and the surrounding structure, and it also serves as the protective film that prevents side etching and corrosion. This multi-functionality resolves the contradiction by eliminating the need for an additional protective film layer.
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 allows for effective protection of the bump without increasing the number of manufacturing steps, preventing side etching and corrosion, while maintaining high adhesion and electrical connectivity.
Implementation Method 1
a side face of the bump is covered with the adhesion layer
Implementation Method 2
the area of an upper surface of the bump is larger than the area of a lower surface of the bump... the side face of the bump is covered with the adhesion layer
Data Source
AI summary
The present invention provides an ink jet recording head which includes a substrate, an energy generating element which is disposed on the substrate and generates energy for discharging a liquid, an electrode which is disposed on the substrate and is electrically connected to the energy generating element, a passage-forming member which is disposed on the substrate, an adhesion layer which is disposed on the substrate and facilitates adhesion between the passage-forming member and the substrate, and a bump disposed on the electrode. The area of an upper surface of the bump is larger than the area of a lower surface of the bump, the lower surface being located on the substrate side, the upper surface being located opposite the lower surface, and a side face of the bump is covered with the adhesion layer. Thereby, a protective film is formed around the bump.