Lift-off Method for Array Substrate Photoresist Removal
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Solution Overview
Problem
The lift-off method for manufacturing array substrates in liquid crystal display (LCD) devices is inefficient due to long processing times and potential damage to electrodes from excessive exposure to strippers, leading to reduced productivity and poor contact between pixel and drain electrodes.
Innovation Solution
A method involving the formation of a photoresist pattern, a first material layer, and subsequent heat-treatment to facilitate faster and more efficient removal of the photoresist pattern and transparent conductive layer, reducing processing time and minimizing electrode damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lift-off method is used to remove the photoresist pattern and transparent conductive layer, then the manufacturing process can be simplified, but the processing time becomes excessively long (over 6 minutes 30 seconds) and electrode damage occurs
Solution Approach 1:
The patent changes the chemical parameters of the stripper by adding specific additives (such as benzyl alcohol, ethyl lactate, or cyclohexanone) to the conventional stripper solution. This parameter modification enables the stripper to effectively remove the transparent conductive layer (ITO) along with the photoresist pattern in a single process step, reducing the total processing time to under 6 minutes 30 seconds while preventing electrode damage through controlled chemical composition
Solution Approach 2:
The patent applies a preliminary heat treatment step (annealing at 80-150°C for 1-30 minutes) before the stripper application. This preliminary action modifies the photoresist pattern and interface structure in advance, creating optimal conditions for the subsequent lift-off process. The heat treatment facilitates faster and more complete removal of both the photoresist and transparent conductive layer, significantly reducing processing time while maintaining electrode integrity
2Manufacturing precision
If excessive exposure to strippers is applied to remove the photoresist pattern, then complete removal is achieved, but electrode damage occurs and contact between pixel and drain electrodes deteriorates
Solution Approach 1:
The patent modifies the stripper solution composition by incorporating specific additives (benzyl alcohol, ethyl lactate, cyclohexanone, or their mixtures) that enable complete photoresist removal with reduced exposure time. These chemical parameter changes allow the stripper to selectively remove the photoresist and transparent conductive layer without attacking the underlying electrode materials, thus maintaining electrode contact quality while achieving complete pattern removal
Solution Approach 2:
The patent introduces an intermediary heat treatment step that prepares the photoresist pattern and interface structure before stripper application. This intermediary action creates optimal conditions for selective removal, allowing the stripper to efficiently remove the photoresist and transparent conductive layer while protecting the electrodes from damage, thereby maintaining both removal completeness and electrode reliability
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 significantly reduces the overall manufacturing time to less than 6 minutes and 30 seconds, enhances productivity, and decreases the risk of electrode damage, while maintaining effective contact between pixel and drain electrodes.
Implementation Method 1
heat-treating the substrate including the transparent conductive layer and the photoresist pattern
Data Source
AI summary
A method of forming a pattern includes forming a photoresist pattern on a substrate, forming a first material layer on substantially an entire surface of the substrate including the photoresist pattern, heat-treating the substrate including the first material layer and the photoresist pattern, and forming the pattern by removing the photoresist pattern and the portion of the first material layer on the photoresist pattern. A method of manufacturing an array substrate includes forming a pixel region bounded by gate and data lines, and a thin film transistor; an insulating layer is selectively removed to form a passivation layer using a photoresist pattern as an etching mask; a transparent conductive layer is formed on substantially the entire substrate, and the substrate is heat treated. The photoresist pattern and the portion of the transparent conductive layer on the photoresist pattern are removed by a stripping material.