Conductive Feature Etching with Anti-Corrosive Primer Layers
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Solution Overview
Problem
Wet etching processes in electronic and optical device manufacturing often result in undercutting, leading to reduced conductivity and undesirable sloped side-walls, which limits feature density and increases waste due to inefficient use of photo-sensitive materials.
Innovation Solution
Application of an undercut-reducing primer layer containing anti-corrosive materials like azole groups or Schiff bases, followed by a bi-component etch mask formation through a chemical reaction with etch-resist ink, immobilizing the ink to prevent spreading and enhance pattern accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wet etching process is used to remove conductive layer material, then the etching process is simple and effective, but undercutting occurs that reduces conductivity and creates sloped side-walls
Solution Approach 1:
An anti-corrosive material layer is introduced as an intermediary between the etch mask and the conductive layer. This mediator prevents the etchant from attacking the conductive layer at the interface, thereby eliminating undercutting while preserving the simplicity of the wet etching process. The anti-corrosive layer acts as a protective barrier that allows vertical side-wall formation without complicating the overall manufacturing process.
Solution Approach 2:
The anti-corrosive material layer is applied to the conductive layer before the etch mask is formed and before the etching process begins. This preliminary protective action ensures that when the wet etching subsequently removes conductive material, no undercutting occurs at the mask-conductive layer interface, maintaining precise feature width control throughout the etching process.
2Loss of substance
If the etch mask covers less than 50% of the substrate surface, then material waste is reduced, but the photo-sensitive material is discarded as waste requiring inefficient blanket coating
Solution Approach 1:
The traditional mechanical blanket coating process for applying photo-sensitive material is replaced with a direct print process. This substitution allows the etch mask to be applied only where needed on the substrate surface, reducing photo-sensitive material waste while simplifying the manufacturing process by eliminating the blanket coating and subsequent discarding steps.
3Loss of substance
If non-impact printing is used to apply liquid etch mask ink, then material waste is reduced, but the ink spreads and translates uncontrollably causing poor resolution
Solution Approach 1:
The anti-corrosive material layer serves as an intermediary surface that receives the liquid etch mask ink through non-impact printing. This intermediary layer provides a controlled interface that prevents uncontrolled spreading and translation of the ink, maintaining high pattern resolution while allowing efficient use of etch mask material through direct printing methods.
Solution Approach 2:
The properties of the anti-corrosive material layer are specifically designed to control the interaction with liquid etch mask ink. By adjusting parameters such as surface energy, porosity, or chemical composition of the anti-corrosive layer, the ink spreading and translation are controlled, enabling high-resolution patterning through non-impact printing while minimizing material waste.
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
Reduces undercutting, resulting in more vertical side-walls, improved conductivity, higher feature density, and reduced waste by minimizing the use of photo-sensitive materials and improving etch mask resolution.
Implementation Method 1
a first layer of anti-corrosive material is applied over an unpatterned device layer... the anti-corrosive material layer... reduces undercutting of a feature
Implementation Method 2
a second layer of etch-resist material is formed over the anti-corrosive material layer by image-wise printing a liquid etch-resist ink... a bi-component etch mask material is formed through a chemical reaction with the primer layer
Implementation Method 3
the bi-component etch mask material is formed through a chemical reaction with the primer layer... wherein the bi-component etch mask material is insoluble in the etchant solution
Data Source
Figure 1A~1D
Figure 2A~2C
Figure 3A~3B
AI summary
A method of making a device patterned with one or more electrically conductive features includes depositing a conductive material layer over an electrically insulating surface of a substrate, depositing an anti-corrosive material layer over the conductive material layer, and depositing an etch-resist material layer over the anti-corrosive material layer. The etch-resist material layer may be deposited over the anti-corrosive material layer, and the anti-corrosive material layer forming a bi-component etch mask in a pattern resulting in covered portions of the conductive material layer and exposed portions of the conductive material layer, the covered portions being positioned at locations corresponding to one or more conductive features of the device. A wet-etch process is performed to remove the exposed portions of the conductive material layer from the electrically insulating substrate, and the bi-component etch mask is removed to expose the remaining conductive material. Systems and devices relate to devices with patterned features.