Copper Wire Electroplating via Sulfur-Containing Electrolyte
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Solution Overview
Problem
The manufacturing of copper wires for flat panel display devices faces issues such as oxidation, moisture corrosion, poor adhesion, and diffusion between layers, leading to difficulties in controlling taper angles and etching processes, which result in voids and shorts between conductive metal lines, damaging the active channel and reducing yield.
Innovation Solution
A method using an electrolyte solution comprising a sulfur-containing compound, such as an organic sulfide surfactant, for electroplating copper wires on a substrate, which eliminates the need for etching and allows for controlled taper angles, improving step-coverage and reducing voids between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multilayered copper wires are used to solve oxidation and adhesion problems, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent uses a composite structure of copper wire embedded in sulfur-containing polymer matrix (such as polysulfone, polyether sulfone, or polyimide). This composite approach provides oxidation resistance through the sulfur-containing polymer coating while maintaining structural integrity, eliminating the need for complex multilayered copper wire structures.
Solution Approach 2:
The sulfur-containing polymer acts as an intermediary protective layer between the copper wire and the external environment. This intermediary layer prevents direct contact between copper and oxidizing agents, providing corrosion protection without requiring multiple copper layers.
2Manufacturing precision
If conventional etching process is used to form copper wires, then manufacturing precision is achieved, but voids form between layers
Solution Approach 1:
The patent extracts and eliminates the etching process from the manufacturing sequence. Instead of depositing copper and then etching to form wires, the invention directly forms copper wires through electroplating on patterned substrates, removing the source of void formation entirely.
Solution Approach 2:
The patent performs preliminary patterning of the substrate before copper deposition. By pre-forming the pattern structure and then directly plating copper conformally, the method ensures complete coverage and eliminates voids that would otherwise form during subsequent etching operations.
3Manufacturing precision
If etching process is applied to control taper angle, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
Instead of depositing copper first and then etching to create the desired shape, the patent inverts the sequence by pre-forming the pattern structure and then depositing copper conformally. This eliminates the need for etching while achieving precise taper angle control through the deposition process itself.
Solution Approach 2:
The patent controls taper angle by adjusting deposition parameters (such as deposition rate, temperature, or angle of incidence) rather than using etching parameters. This changes the control mechanism from etching-based to deposition-based, simplifying the overall process.
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 simplifies the manufacturing process, reduces the formation of voids, prevents shorts and damage to the active channel, and increases the yield of flat panel display devices by naturally forming copper wires with controlled taper angles without the complexity of etching.
Implementation Method 1
plating a copper layer on the exposed part of the seed layer with a electrolyte solution comprising a sulfur-containing compound
Data Source
AI summary
A method for manufacturing copper wires on a substrate for a flat panel display device is disclosed. The method comprises following steps: providing a substrate; forming a seed layer on the surface; forming a patterned photoresist on the surface of the seed layer to expose a part of the seed layer; and plating a copper layer on the exposed part of the seed layer. As the copper layer is plated, an electrolyte solution comprises a sulfur-containing compound is used. The angle between the surface of the copper layer and the contact surface of the seed layer is greater than 0 degree and less than 90 degree. Through the method illustrated above, the film step-coverage in the following process can be improved, the generated voids in device can be reduced, the manufacturing steps can be simplified, and the complicated etching process can be avoided.