Pulsed Laser Direct Writing for Copper TFT Electrodes
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Solution Overview
Problem
Current manufacturing techniques for copper thin-film transistor (TFT) electrodes, such as photolithography, are complex and lead to material waste, and the laser direct writing technique for copper nanoparticles results in oxidation, reducing electrical conductivity.
Innovation Solution
A direct writing method using an ultra-high pulsed laser to melt copper nanoparticles for forming gate and source/drain layers on an array substrate, with a wavelength range of 350 to 1064 nm and a scanning speed of 5 to 10 mm/s, effectively preventing copper oxidation and simplifying the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If photolithography technique is used to prepare copper TFT electrodes, then the manufacturing process can be completed with conventional methods, but the process becomes complicated and material waste increases
Solution Approach 1:
The patent extracts and eliminates the complex photolithography steps (photoresist coating, photolithography, wet etching, photoresist stripping) from the manufacturing process, replacing them with a simplified direct writing technique that deposits copper material only where needed, thereby reducing process complexity while maintaining manufacturing capability
Solution Approach 2:
The patent replaces the mechanical/chemical photolithography system with a direct writing system that uses controlled material deposition, substituting the multi-step mechanical and chemical processes with a more direct approach that reduces both process complexity and material waste
2Device complexity
If laser direct writing technique is used to prepare copper electrodes from copper nanoparticles, then the manufacturing process is simplified, but copper oxidation occurs and electrical conductivity decreases
Solution Approach 1:
The patent employs an inert atmosphere (such as nitrogen or argon environment) during the laser direct writing process to prevent copper nanoparticles from oxidizing, thereby maintaining the electrical conductivity and reliability of the copper electrodes while still utilizing the simplified direct writing technique
Solution Approach 2:
The patent uses pulsed laser irradiation instead of continuous laser, applying periodic action to melt and sinter copper nanoparticles. The pulsed nature allows brief intervals for heat dissipation and prevents excessive heating that could promote oxidation, while still achieving the desired copper electrode formation with maintained conductivity
3Quantity of substance
If conventional photolithography is used, then material deposition can be achieved, but material waste increases due to subtractive manufacturing
Solution Approach 1:
The patent inverts the conventional subtractive manufacturing approach (photolithography with etching) and adopts an additive manufacturing approach (direct writing). Instead of depositing material everywhere and then removing unwanted portions, the system directly deposits copper material only at the desired electrode locations, thereby significantly reducing material waste and improving material utilization
4Reliability
If copper is used as wiring material to reduce resistance, then electrical conductivity improves, but copper oxidation becomes a critical issue that must be prevented
Solution Approach 1:
The patent uses an inert atmosphere during the laser direct writing process to create a protective environment that prevents copper from reacting with oxygen, thereby maintaining the high electrical conductivity of copper electrodes while eliminating the harmful oxidation effect
Solution Approach 2:
The patent uses ultra-high power density pulsed laser to rapidly melt and sinter copper nanoparticles in extremely short pulses, rushing through the processing step so quickly that oxidation is minimized. The rapid processing speed reduces the time window for oxidation to occur while still achieving complete copper electrode formation
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 method reduces copper oxidation, simplifies the manufacturing process, and achieves high conductivity copper electrodes with reduced material waste and improved production speed.
Implementation Method 1
using a direct writing technique of an ultra-high pulsed laser to melt copper nanoparticles and print a gate layer and a source and drain layer
Data Source
AI summary
The present invention provides a manufacturing method of an array substrate, including steps of: providing a flexible substrate layer, forming a buffer layer, forming an active layer, forming a gate insulating layer, forming a gate layer, forming an interlayer insulating layer, forming a source and drain layer, forming an organic planarization layer, forming an anode layer. An array substrate manufactured by the above manufacturing method, and the array substrate includes laminated a flexible substrate layer, a buffer layer, an active layer, a gate insulating layer, a gate layer, an interlayer insulating layer, a source and drain layer, an organic planarization layer, and an anode layer, which are disposed in a stack.