Copper-Molybdenum Wiring Etching for Oxide Semiconductor Displays
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Solution Overview
Problem
Current methods for manufacturing semiconductor devices with oxide semiconductors lack a suitable etchant and manufacturing process for forming copper-containing metal films, which are essential for improving display quality and productivity, especially in larger screen displays where wiring resistance issues lead to display unevenness and defects in grayscale.
Innovation Solution
A method involving the formation of a first conductive film, an insulating film, an oxide semiconductor film, and a second conductive film with molybdenum and copper as main components, using an etchant composed of an aqueous solution of organic acid and hydrogen peroxide with a specific pH range and component ratio to etch the copper-containing metal film, where the oxide semiconductor film acts as an etching stopper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper film is used as wiring material to reduce resistance, then display quality is improved, but adhesion to base film deteriorates and copper diffusion into semiconductor layer occurs
Solution Approach 1:
The patent uses a composite metal film structure consisting of a copper layer (for low resistance) and a molybdenum layer (for adhesion and diffusion barrier). This composite structure combines the advantages of both materials: copper provides low resistance for improved display quality, while molybdenum provides excellent adhesion to the base film and prevents copper diffusion into the semiconductor layer, thereby resolving the technical contradiction.
2Manufacturing precision
If aluminum film is used as wiring material, then adhesion to base film is maintained, but resistance is high causing display unevenness and grayscale defects
Solution Approach 1:
The patent replaces the conventional aluminum film with a composite metal film structure of copper and molybdenum. The copper layer provides low resistance to prevent display unevenness and grayscale defects, while the molybdenum layer ensures good adhesion to the base film. This composite structure simultaneously improves both adhesion and display quality, resolving the technical contradiction between these two parameters.
3Ease of manufacture
If existing etchant methods are used for copper-containing metal films, then manufacturing process is simple, but etching selectivity and control deteriorate
Solution Approach 1:
The patent optimizes the etching process by carefully controlling the pH value of the etching solution within a specific range (2-4) and adjusting the composition ratios of organic acid and hydrogen peroxide. These parameter changes enable selective etching of the molybdenum layer while protecting the copper layer and oxide semiconductor layer, achieving excellent etching control and selectivity while maintaining process simplicity through a single-step etching method.
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 enables the creation of semiconductor devices with copper-containing metal films having favorable shapes and reduced resistance, improving display quality and productivity by effectively addressing the challenges of display unevenness and grayscale defects in larger screen displays.
Implementation Method 1
an etchant composed of an aqueous solution of organic acid and hydrogen peroxide with a specific pH range and component ratio to etch the copper-containing metal film
Implementation Method 2
where the oxide semiconductor film acts as an etching stopper
Data Source
AI summary
A method for manufacturing a semiconductor device includes the steps of forming a first conductive film over a substrate; forming an insulating film over the first conductive film; forming an oxide semiconductor film over the insulating film to overlap with the first conductive film; forming a second conductive film including a metal film containing molybdenum as its main component and a metal film containing copper as its main component over the oxide semiconductor film; and etching the second conductive film by an etchant. At the time of etching the second conductive film by the etchant, the oxide semiconductor film is used as an etching stopper film. In addition, the etchant which can be used for a transistor including the oxide semiconductor film is provided.