Copper Etching Margin via Moderated Oxidizing Agent
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing display substrates is the increased electric resistance and signal delays in gate and data lines due to the high resistivity of metals used, particularly copper, which requires strong oxidizing agents for etching, causing damage to pre-patterned layers and making it difficult to control the etch rate, leading to unstable metal patterns.
Innovation Solution
A method involving the use of a moderated etching composition with ammonium persulfate and an azole-based compound to over-etch a copper-based layer, minimizing damage to underlying patterns while maintaining a stable etch rate, thereby forming a metal pattern with improved etching margin and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used to form gate lines and data lines, then electric resistance is reduced and conductivity is improved, but the metal becomes difficult to etch and requires strong oxidizing agents that damage pre-patterned layers
Solution Approach 1:
The patent introduces an intermediary substance (organic compound such as benzotriazole, 1,2,4-triazole, or imidazole) into the etching composition. This intermediary acts as a moderating agent that reduces the aggressiveness of the strong oxidizing agent (ammonium persulfate), allowing copper to be etched without requiring excessively strong conditions that would damage underlying patterns. The intermediary mediates between the need for effective copper etching and the protection of pre-patterned layers.
Solution Approach 2:
The patent modifies the chemical parameters of the etching composition by controlling the concentration ratios of key components. Specifically, it maintains ammonium persulfate at 0.1-50% by weight and adds organic compounds at 0.01-5% by weight. This parameter optimization allows the etching solution to effectively etch copper while being gentle enough to preserve underlying patterns, resolving the contradiction between etchability and selectivity.
2Productivity
If strong oxidizing agents are used to etch copper, then etching effectiveness is improved, but control over etch rate becomes difficult and underlying patterns are damaged
Solution Approach 1:
The organic compound serves as a moderating agent that controls the reaction between the oxidizing agent and copper. It prevents runaway etching reactions while maintaining effective etching speed, thus providing both productivity and precision. The intermediary ensures that the etch rate remains controllable even with the presence of strong oxidizing agents.
Solution Approach 2:
The etching composition is designed with components that provide self-regulating feedback. The organic compound reacts with copper to form protective complexes that slow down the etching rate as etching progresses, preventing over-etching. This natural feedback mechanism maintains manufacturing precision while preserving underlying patterns.
3Manufacturing precision
If copper-based layer is over-etched to compensate for etching variability, then pattern stability is improved, but damage to pre-patterned layers increases
Solution Approach 1:
The organic compound in the etching composition acts as a protective intermediary that allows for controlled over-etching. It moderates the etching reaction to maintain stable pattern formation while preventing excessive etching that would damage underlying patterns. The intermediary ensures that over-etching can be performed safely within the specified parameters.
Solution Approach 2:
The etching composition is pre-formulated with moderating agents that cushion against etching variability. This prior cushioning allows the process to tolerate variations in etching conditions and time without causing damage to underlying patterns, thereby improving pattern stability while protecting sensitive structures.
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 allows for the formation of stable metal patterns with controlled etching, reducing signal delays and improving the reliability of the manufacturing process by preventing damage to pre-patterned layers and maintaining a consistent etch rate, thus enhancing the etching margin and overall substrate quality.
Implementation Method 1
an etching composition including as an oxidizing agent thereof, ammonium persulfate
Data Source
AI summary
A method of forming a metal pattern on a display substrate includes blanket depositing a copper-based layer having a thickness between about 1,500 Å and about 5,500 Å on a base substrate, and forming a patterned photoresist layer on the copper-based layer. The copper-based layer is over-etched by an etching composition containing an oxidizing moderating agent where the over-etch factor is between about 40% and about 200% while using the patterned photoresist layer as an etch stopping layer, and where the etching composition includes ammonium persulfate between about 0.1% by weight and about 50% by weight, includes an azole-based compound between about 0.01% by weight and about 5% by weight and a remainder of water. Thus, reliability of the metal pattern and that of manufacturing a display substrate may be improved.