Multilayer Element Board Wiring for Through-Hole Corrosion Resistance
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Solution Overview
Problem
The reduction in size of heating resistance elements and wiring in inkjet printing heads leads to increased aspect ratios of through-holes, resulting in poor coverability of barrier metal layers, which causes corrosion and destabilization of heating resistance elements, affecting image quality and functionality.
Innovation Solution
A multi-layer structure with a corrosion-resistant conductive layer is introduced, comprising a stacked configuration of conductive layers and metal plugs to enhance coverability and prevent corrosion, particularly at the corners of through-holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of heating resistance elements and wiring is reduced, then the density and integration are improved, but the aspect ratio of through-holes increases leading to poor coverability of barrier metal layers
Solution Approach 1:
The patent introduces a corrosion-resistant conductive layer as an additional dimension between the conductive layer and the through-hole barrier metal layer. This extra layer provides comprehensive coverage including corner areas that were previously inaccessible to the barrier metal layer, effectively solving the coverability issue without changing the through-hole geometry or reducing element size.
Solution Approach 2:
The patent employs a composite structure consisting of multiple conductive layers with different properties: a conventional conductive layer for electrical connection and a corrosion-resistant conductive layer specifically for protection. This composite approach allows each layer to fulfill its specialized function while working together to prevent corrosion at the through-hole interfaces.
2Ease of manufacture
If the aspect ratio of through-holes increases, then the manufacturing complexity is reduced, but the corrosion resistance of wiring portions deteriorates
Solution Approach 1:
The corrosion-resistant conductive layer acts as an intermediary between the conductive layer and the ink environment. It specifically protects the corner areas of through-holes where corrosion initially occurs, serving as a mediator that prevents direct contact between corrosive substances and the underlying wiring structures.
Solution Approach 2:
The corrosion-resistant conductive layer is applied in advance to areas prone to corrosion before the corrosion can occur. By pre-coating the corner regions and through-hole interfaces with this protective layer, the patent prevents corrosion from initiating or propagating, rather than attempting to repair corrosion after it begins.
3Reliability
If barrier metal layers are applied to through-holes, then corrosion is suppressed, but the coverability in corner areas becomes insufficient when aspect ratio increases
Solution Approach 1:
The patent adds another dimensional layer (the corrosion-resistant conductive layer) between the existing conductive layer and the through-hole barrier metal layer. This additional dimension extends protection to corner areas that were previously uncovered, ensuring comprehensive coverage without altering the barrier metal layer's existing structure or application method.
Solution Approach 2:
The corrosion-resistant conductive layer is specifically positioned and applied to areas most susceptible to corrosion, namely the corner regions and through-hole interfaces. This localized approach concentrates the protective function where it is most needed, rather than uniformly treating all surfaces, thereby improving corner coverability while maintaining manufacturing efficiency.
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
The multi-layer structure effectively suppresses corrosion, ensuring stable operation of heating resistance elements and maintaining image quality by preventing ink penetration and dissolution, even with increased through-hole aspect ratios.
Implementation Method 1
the corrosion-resistant conductive layer is formed of a material having a high corrosion resistance to an ink
Implementation Method 2
a thermal system is a system which generates bubbles in nozzles by locally heating a liquid such as an ink from the nozzles
Implementation Method 3
generates bubbles in nozzles by locally heating a liquid such as an ink from the nozzles, and ejecting the ink from the nozzles by unit of the bubbles
Implementation Method 4
heating resistance elements for heating a liquid are formed on a semiconductor substrate
Data Source
AI summary
Provided is an element board having a multi-layer structure, including: a heater layer; a first wiring layer which has a stacked structure portion of three or more layers sequentially stacked in a conduction direction, in which a wiring connected to a plurality of heaters is formed; and a second wiring layer in which a common wiring for supplying a voltage to the plurality of heaters from an outside is formed, wherein the plurality of heaters are connected to the common wiring through the first wiring layer, the first wiring layer has a stacked structure of three or more layers, and the stacked structure portion includes a corrosion-resistant conductive layer, a first conductive layer, and a second conductive layer.