Etchant Composition for Titanium and Copper Etching
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Solution Overview
Problem
The existing etching processes for manufacturing TFT display panels, particularly those using titanium/copper double layers, face challenges such as poor etching profiles and difficulty in subsequent processes due to the complexity of etching multiple metal layers, and generate insoluble precipitates that can contaminate substrates and affect etching efficiency.
Innovation Solution
An etchant comprising persulfate, fluoride compounds, inorganic acids, N-containing heterocyclic compounds, chloride compounds, copper salts, organic acids, and electron-donating compounds is used to effectively etch titanium and copper layers, controlling etching rates and preventing precipitate formation, thereby improving etching profiles and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a titanium/copper double layer is simultaneously etched, then the gate wiring and data wiring can be formed, but the etching profile becomes bad and subsequent processes become difficult
Solution Approach 1:
The etching process is divided into two separate steps: first etching the titanium layer, then etching the copper layer. This segmentation allows each metal layer to be etched with optimized parameters, achieving good etching profiles for both layers while maintaining high productivity.
Solution Approach 2:
The titanium layer is etched first as a preliminary step before etching the copper layer. This preliminary action removes the titanium barrier layer, exposing the copper layer for subsequent etching and preventing titanium contamination during copper etching.
2Ease of manufacture
If multiple metal layers are used instead of a single copper layer, then photoresist coating and patterning become easier, but the etching process becomes more complex
Solution Approach 1:
The etching process for multiple metal layers is segmented into separate etching steps for each layer, with the titanium layer etched first followed by the copper layer. This segmentation simplifies the overall process by allowing each layer to be etched independently with optimized parameters.
Solution Approach 2:
The titanium layer serves as an intermediary layer that facilitates the etching process. It is etched first to expose the copper layer, and its removal is necessary for subsequent copper etching, acting as a mediator between the photoresist patterning and copper etching steps.
3Productivity
If conventional etchants are used for titanium and copper, then etching can be performed, but insoluble precipitates are generated that contaminate substrates and affect etching efficiency
Solution Approach 1:
The etchant composition is modified by changing the oxidizing agent from conventional options to persulfate, and by adjusting the concentrations of fluoride compounds, organic acids, and other additives. These parameter changes prevent precipitate formation while maintaining high etching efficiency for both titanium and copper layers.
Solution Approach 2:
The etchant is formulated as a composite solution containing multiple components: persulfate as the primary oxidizing agent, fluoride compounds for titanium etching, organic acids for copper etching, and other additives to prevent precipitate formation. This composite etchant simultaneously etches both metal layers without generating harmful precipitates.
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
The etchant provides a rapid and controlled etching process for titanium and copper layers, preventing over-etching and photoresist cracks, maintaining substrate integrity, and avoiding insoluble precipitate generation, thus enhancing the manufacturing efficiency and quality of TFT display panels.
Implementation Method 1
a persulfate from about 0.5 wt % to about 20 wt %
Implementation Method 2
a fluoride compound from about 0.01 wt % to about 2 wt %
Data Source
AI summary
An etchant composition is provided comprising a persulfate from 0.5 to 20 wt %; a fluoride compound from 0.01 to 2 wt %; an inorganic acid from 1 to 10 wt %; a N (nitrogen atom)-containing heterocyclic compound from 0.5 to 5 wt %; a chloride compound from 0.1 to 5 wt %; a copper salt from 0.05 to 3 wt %; an organic acid or an organic acid salt from 0.1 to 10 wt %; an electron-donating compound from at 0.1 to 5 wt %; and a solvent of the residual amount. Also provided is a method of manufacturing a display device by using the same.