Cu-Interconnection Etching Liquid Copper Ion Filtration
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Solution Overview
Problem
The Cu-interconnection etching process faces issues with rapid decomposition of H2O2 etching liquid due to increasing copper ion concentration, leading to reduced etching liquid lifetime, increased production costs, and instability in etching rates, which limits the yield and stability of Cu-interconnection production.
Innovation Solution
A method and device that utilize a first and second concentration monitoring device to measure and control copper ion concentrations in the etching liquid, employing filters such as reverse osmosis membranes and fabrics to filter copper ions, allowing for cyclic reflow of the etching liquid, thereby maintaining optimal copper ion levels and extending the etching liquid's usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the etching liquid is used continuously in the Cu-interconnection process, then the productivity is improved, but the copper ion concentration increases leading to accelerated H2O2 decomposition and potential explosions
Solution Approach 1:
The patent extracts and removes copper ions from the etching liquid using a filtration system with filters having specific pore sizes (0.01-10 micrometers). This extraction process separates the harmful copper ions from the etching liquid, allowing the liquid to be reused safely and extending its usage lifetime while preventing dangerous concentration buildup
Solution Approach 2:
The patent implements a system where copper ions are discarded through filtration while the etching liquid is recovered and reused. The filtration system continuously or periodically removes copper ions, and the cleaned etching liquid is returned to the process, thereby extending the liquid's usable life and reducing waste
2Productivity
If the copper ion concentration is allowed to increase, then the etching rate initially improves, but the H2O2 decomposition accelerates causing safety hazards and limiting usage lifetime
Solution Approach 1:
The patent implements a feedback control system that monitors copper ion concentration in the etching liquid and adjusts the filtration process accordingly. When copper ion concentration approaches levels that would accelerate H2O2 decomposition, the system activates filtration to remove ions, maintaining safe operating conditions while maximizing etching productivity and liquid reuse time
Solution Approach 2:
The patent applies preliminary filtration to remove copper ions before they can accumulate to dangerous concentrations that would trigger rapid H2O2 decomposition. By proactively filtering the etching liquid during use, the system prevents the harmful acceleration of decomposition while maintaining etching effectiveness
3Reliability
If new etching liquid is frequently replaced to maintain safety, then the copper ion concentration is controlled, but the production cost increases
Solution Approach 1:
Instead of discarding and replacing etching liquid frequently, the patent recovers the liquid by filtering out copper ions. This recovery process allows the same etching liquid to be used repeatedly, significantly reducing the cost of consumables while maintaining safety through controlled copper ion removal
Solution Approach 2:
The patent changes the physical state or composition parameters of the etching liquid by removing copper ions through filtration. This parameter change (reducing copper ion concentration) restores the liquid's safety and effectiveness, allowing continued use without replacement and reducing production costs
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 effectively reduces copper ion concentrations, prolongs the etching liquid's usage life, lowers production costs, and enhances the stability and yield of Cu-interconnection production by maintaining consistent etching rates.
Implementation Method 1
employing a filter to perform copper ion filtering to the etching liquid in the etching liquid tank
Implementation Method 2
The filter in the step 2 further comprises one or more reverse osmosis membranes connected in series which can filter the copper ion
Data Source
AI summary
The present invention provides a method of improving lifetime of etching liquid and yield in Cu-interconnection process and a Cu-interconnection etching device. The method comprises: step 1, providing an etching spray rising tank (1) and an etching liquid tank (2) connected to the etching spray rising tank (1), and the etching liquid tank (2) contains etching liquid; step 2, employing a first concentration monitoring device (4) to measure a copper ion concentration of the etching liquid in the etching liquid tank (2), and employing a filter (5) to perform copper ion filtering to the etching liquid in the etching liquid tank (2); step 3, employing a second concentration monitoring device (6) to measure a copper ion concentration of the etching liquid after filtering in the step 2, and controlling an amount of the filters (5) employed in the step 2 and reflowing the etching liquid after filtering to the etching liquid tank (2). The present invention can reduce the copper ion concentration of the etching liquid to promote the usage lifetime of the etching liquid and reduce the production cost for raising the stability and yield of the Cu-interconnection production.