Triple-Layer Metal Wire Structure for OLED Display Impurity Control
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Solution Overview
Problem
The generation of impurities during the photolithography process for forming metal wires and thin film transistors in OLED displays, particularly due to the reaction of aluminum with developing solutions, leads to noise and defects in the manufacturing process.
Innovation Solution
A method involving a triple-layered structure of metal layers, where the upper layer completely covers the end of the middle layer, preventing exposure to the developing solution and thus minimizing impurity generation, is used to form wires and thin film transistors. This structure includes a sputtering process to deposit layers of molybdenum, aluminum, nickel, and lanthanum, with the upper layer acting as a mask to etch the metal layers and form the desired patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single metal layer is used to form wires, then the manufacturing process is simple, but impurities are generated when the metal reacts with developing solution
Solution Approach 1:
The metal layer is divided into multiple segments (lower layer, middle layer, upper layer) with different materials and functions. The lower layer (Aluminum) provides conductivity, the middle layer (Molybdenum) provides etch resistance, and the upper layer (Nickel/Lanthanum) protects against developing solution reaction, thereby eliminating impurity generation while maintaining manufacturing feasibility
Solution Approach 2:
The patent uses composite material structure where different metal layers (Aluminum, Molybdenum, Nickel, Lanthanum) are combined to create a wire structure that simultaneously achieves conductivity, etch resistance, and chemical stability against developing solution, preventing impurity generation
2Reliability
If aluminum is used to produce low resistance wire, then electrical conductivity is improved, but reaction with developing solution generates impurity
Solution Approach 1:
The upper layer (Nickel and/or Lanthanum) acts as an intermediary protective barrier between the aluminum lower layer and the developing solution. This intermediary layer prevents direct contact and chemical reaction, eliminating impurity generation while allowing the aluminum layer to maintain its low resistance and high conductivity function
3Manufacturing precision
If photoresist pattern is formed by exposing and developing, then metal layer can be patterned, but developing solution causes metal impurity
Solution Approach 1:
The upper protective layer (Nickel/Lanthanum) is formed in advance before the photoresist patterning and developing process. This preliminary protective layer prevents the developing solution from attacking the metal layers during the necessary photoresist development step, allowing precise patterning without impurity generation
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 effectively prevents impurity formation, reducing noise and defects in the metal wire and thin film transistor array panels, enhancing the reliability and quality of OLED displays by ensuring that the metal layers are not exposed to the developing solution.
Implementation Method 1
This structure includes a sputtering process to deposit layers of molybdenum, aluminum, nickel, and lanthanum
Data Source
AI summary
A manufacturing method of a wire including: forming a lower layer on a substrate; forming a middle layer on the lower layer; forming an upper layer on the middle layer; forming, exposing, and developing a photoresist layer on the upper layer to form a photoresist pattern; and etching the upper layer, the middle layer, and the lower layer by using the photoresist pattern as a mask to form a wire such that the upper layer covers an end of the middle layer.