Electrode Patterning on Softening Polymers Without Organic Residue
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Solution Overview
Problem
Conventional methods for forming electrode layers on softening polymers often result in residual organic material, leading to reduced sensitivity and potential delamination, and aggressive clean-up procedures can be lengthy and damaging to the electrode surface.
Innovation Solution
A liftoff process using an inorganic liftoff layer with a thin film stress of less than 150 MPa, combined with a horizontal liftoff etch and reactive ion etch processes, to pattern electrodes on softening polymers while minimizing organic residue and maintaining device integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to form electrode layers on softening polymers, then the electrode layers can be fabricated, but residual organic material remains leading to reduced sensitivity and potential delamination
Solution Approach 1:
The patent extracts and removes the inorganic liftoff layer after electrode formation, taking with it any residual organic material that would otherwise remain on the electrode surface. This is achieved through chemical etching processes that selectively remove the liftoff layer while leaving the electrode intact, thereby eliminating the source of contamination and improving electrode sensitivity and adhesion.
Solution Approach 2:
The inorganic liftoff layer is deposited beforehand as a sacrificial layer that prevents organic material from adhering to the electrode during fabrication. This preliminary protective action ensures that when the liftoff layer is removed, the electrode surface is clean and free of contaminants, enhancing both sensitivity and adhesion without requiring aggressive clean-up procedures.
2Reliability
If aggressive clean-up procedures are used to remove residual organic material, then sensitivity may improve, but the procedures are lengthy and damaging to the electrode surface
Solution Approach 1:
The patent converts the potentially harmful effect of residual organic material into a benefit by using the inorganic liftoff layer as a sacrificial barrier. The liftoff layer absorbs the contamination risk during fabrication, and its subsequent removal cleanly exposes the electrode surface without requiring time-consuming aggressive clean-up procedures that could damage the electrode.
Solution Approach 2:
The inorganic liftoff layer serves as an intermediary between the organic photoresist material and the electrode surface. It allows organic material to be present during fabrication without contaminating the electrode, and its removal subsequently reveals a clean electrode surface, eliminating the need for lengthy clean-up procedures.
3Object-generated harmful factors
If aggressive clean-up procedures are used to remove residual organic material, then organic residue may reduce, but the electrode surface is damaged
Solution Approach 1:
The patent extracts the contaminant removal function from direct cleaning of the electrode surface and transfers it to the removal of the inorganic liftoff layer. This extraction approach eliminates organic residue without exposing the delicate electrode surface to damaging clean-up procedures, thereby preserving surface roughness and manufacturing precision.
Solution Approach 2:
The inorganic liftoff layer acts as an intermediary that protects the electrode surface during the contamination removal process. By etching away the liftoff layer rather than directly cleaning the electrode, organic residue is eliminated while the electrode surface remains undamaged and maintains its optimal roughness characteristics.
4Reliability
If inorganic liftoff layer with low thin film stress is used, then delamination is prevented, but the liftoff layer must be precisely controlled
Solution Approach 1:
The patent controls the thin film stress parameter of the inorganic liftoff layer by adjusting deposition conditions such as plasma power, pressure, and gas flow rates during sputtering. By optimizing these parameters, the liftoff layer achieves low stress (less than 150 MPa) that prevents delamination while maintaining manufacturability through standard deposition processes.
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 solution effectively reduces residual organic material, enhancing the sensitivity and durability of electrode layers on softening polymers, preventing delamination and maintaining surface roughness for improved charge injection capacity.
Implementation Method 1
removing portions of the inorganic liftoff layer exposed through openings in a patterned photoresist layer on the inorganic liftoff layer by a fluorine plasma dry etch process
Implementation Method 2
removing, by the reactive ion etch process, exposed portions of the cover layer underlying the opening in the inorganic hardmask layer
Implementation Method 3
removing the inorganic liftoff layer by the horizontal liftoff etch can include etchant solvent exposure of the: inorganic liftoff layer, a photoresist layer on the inorganic liftoff layer and portions of the electrode layer on the photoresist layer
Data Source
AI summary
A method of manufacturing an electrical device, comprising: forming a patterned inorganic liftoff layer to expose a target electrode site on a softening polymer layer, depositing an electrode layer on the inorganic liftoff layer and on the exposed target electrode site, and removing the inorganic liftoff layer by a horizontal liftoff etch to leave the electrode layer on the exposed target electrode site.