Wet Etching Cycles With Fresh Etchant for Faster Large-Area Processing
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Solution Overview
Problem
Current wet etching methods for semiconductor devices face challenges in reducing etching time and minimizing etchant usage, with immersion etching requiring long times due to stagnant etchant and spin etching wasting etchant without effective contribution.
Innovation Solution
A wet etching method and system that involves repeatedly supplying an etchant to the workpiece, etching with the etchant remaining on the surface, and removing the used etchant, with an optional pressing step using a member with an area equal to or greater than the workpiece surface to ensure even etchant distribution and efficient etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If immersion etching is used with continuous stirring, then etching can be performed without replacement, but etching time becomes excessively long
Solution Approach 1:
The patent implements periodic action by repeatedly performing cycles of supplying fresh etchant, performing etching, and removing used etchant. This cyclic process ensures that fresh etchant is continuously applied to the workpiece surface, maintaining high etching efficiency while reducing total etching time compared to continuous immersion methods.
Solution Approach 2:
The patent applies discarding and recovering by removing used etchant from the workpiece surface after each etching cycle and replacing it with fresh etchant. This ensures that the etchant maintains its effectiveness throughout the process, preventing the time loss that occurs when etchant becomes depleted or contaminated during continuous immersion.
2Productivity
If spin etching is used to supply etchant, then etching can be performed, but most etchant is discharged without contributing to etching
Solution Approach 1:
The patent applies local quality by directing etchant supply precisely to the workpiece surface through a nozzle positioned close to the surface. This localized delivery ensures that etchant is applied exactly where needed for etching, preventing the wasteful discharge of etchant that occurs in spin etching methods where etchant is sprayed over a larger area.
Solution Approach 2:
The patent uses a pressing member as an intermediary between the etchant supply nozzle and the workpiece surface. This pressing member directs and contains the etchant flow, ensuring that the etchant remains in contact with the workpiece surface during the etching process rather than being discharged away, thereby improving etching efficiency and reducing etchant consumption.
3Device complexity
If etching is performed with stagnant etchant in immersion etching, then no etchant replacement is needed, but etch rate decreases over time
Solution Approach 1:
The patent implements continuity of useful action by continuously supplying fresh etchant to the workpiece surface through repeated cycles. This ensures that the etching process always occurs with fresh, effective etchant, maintaining high etch rates throughout the process, whereas immersion etching with stagnant etchant experiences declining etch rates over time.
Solution Approach 2:
The patent uses periodic action to repeatedly replace etchant on the workpiece surface. This periodic renewal of fresh etchant maintains high etching efficiency throughout the process, preventing the etch rate degradation that occurs in immersion etching where etchant becomes stagnant and depleted.
4Area of stationary object
If large area workpieces are etched with conventional methods, then complete coverage is difficult, but etching time increases significantly
Solution Approach 1:
The patent applies periodic action by repeatedly supplying fresh etchant to the workpiece surface in cycles. This repeated application ensures that even large area workpieces receive adequate fresh etchant coverage throughout the etching process, maintaining consistent etching rates across the entire surface and reducing total etching time compared to conventional single-stage methods.
Solution Approach 2:
The patent implements dynamics by using a pressing member that can apply pressure to spread etchant evenly across the workpiece surface. This dynamic approach ensures complete and uniform coverage of large area workpieces, addressing the coverage problem while maintaining efficient etching speeds and reducing overall processing time.
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 reduces etchant usage, enhances etch rate by using fresh etchant for each cycle, and shortens etching time, especially for large workpieces, while allowing for automated repeated etching processes.
Implementation Method 1
etching the to-be-etched surface with the etchant remaining on the to-be-etched surface
Data Source
AI summary
There is provided a wet etching method including an etchant supply step of supplying an etchant from an etchant supply nozzle to a to-be-etched surface of a workpiece, an etching step of etching the to-be-etched surface with the etchant remaining on the to-be-etched surface, and an etchant removal step of, after performing the etching step, removing the etchant, which still remains on the resulting etched surface, from the etched surface. The etchant supply step, the etching step, and the etchant removal step are repeated a plurality of times in this order.