Electrolytic Etching Device with Gas-Liquid Mixing
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Solution Overview
Problem
Existing etching processes for copper on printed circuit boards face challenges in achieving fine and sharp contours due to the decomposition of hydrogen peroxide and high heat generation, leading to inefficient copper etching and increased cooling costs, especially with the miniaturization of conductive lines.
Innovation Solution
An etching device that intensively mixes acidic electrolytes with oxygen or ozone gas to form high concentrations of microbubbles, effectively oxidizing copper(I) ions to copper(II) ions, allowing for efficient electrolyte regeneration and precise etching in narrow spaces by using a Venturi nozzle or liquid jet gas compressor for mixing, which enhances the etching process without moving parts and reduces energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen peroxide is used as oxidizing agent for copper(I) ions, then copper etching can be achieved, but hydrogen peroxide decomposes due to catalytic effect of copper, leading to high consumption and high heat generation requiring energy-intensive cooling
Solution Approach 1:
The patent changes the oxidizing agent from hydrogen peroxide to oxygen or ozone gas, fundamentally altering the chemical reaction parameters. This substitution eliminates the catalytic decomposition issue and reduces heat generation, thereby solving both the productivity and energy loss contradictions
Solution Approach 2:
The patent employs oxygen or ozone gas as strong oxidizing agents to oxidize copper(I) ions back to copper(II) ions. Ozone in particular provides accelerated oxidation with lower heat generation compared to hydrogen peroxide, maintaining etching efficiency while reducing cooling energy requirements
2Productivity
If continuous etching is performed for longer process time to etch large quantity of copper, then productivity increases, but etching fluid becomes depleted of copper(II) ions and etching results deteriorate
Solution Approach 1:
The patent implements continuous regeneration of copper(II) ions through oxygen or ozone oxidation of copper(I) ions in the etching fluid. This continuous regeneration ensures that the etching fluid maintains its effectiveness throughout prolonged operation, enabling both high productivity and consistent etching quality
Solution Approach 2:
The system creates a feedback loop where copper(I) ions produced during etching are continuously oxidized back to copper(II) ions by oxygen or ozone. This closed-loop regeneration mechanism ensures sustained etching capability and consistent results over extended processing times
3Productivity
If chlorine gas is produced during regeneration using hydrochloric acid and hydrogen peroxide, then copper etching can be achieved, but safety risks increase due to chlorine gas production
Solution Approach 1:
The patent uses oxygen or ozone gas as oxidizing agents, creating a safer, inert-like atmosphere compared to chlorine gas production. This substitution eliminates the harmful chlorine gas while maintaining effective copper etching, thereby resolving the contradiction between productivity and safety
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 device achieves efficient electrolyte regeneration and enables rapid, sharply contoured etching in narrow spaces with reduced energy costs and safer oxygen production, maintaining etching effectiveness over prolonged processes.
Implementation Method 1
a first mixing device which is set up to receive an acidic electrolyte containing copper ions and an oxygen gas or ozone gas to form a first liquid-gas mixture
Implementation Method 2
the second mixing device having a suction opening in order to suck in the container liquid present in the area of the suction opening
Implementation Method 3
to direct the first liquid-gas mixture and the sucked-in container liquid into a constriction zone of the second mixing device, so that the sucked-in container liquid mixes with the first liquid-gas mixture
Implementation Method 4
so that a large amount of copper(I) ions in the electrolyte can be oxidized back to copper(II) ions
Implementation Method 5
Cu2SO4 + H2SO4 + O3 → 2CuSO4 + H2O + O2
Implementation Method 6
using a Venturi nozzle or liquid jet gas compressor for mixing
Data Source
Figure 1
Figure 2
AI summary
The invention relates to an etching device for the electrolytic etching of copper on an etching material, comprising a first mixing device, which is designed to receive an acid electrolyte containing copper ions, and an oxygen gas or ozone gas in order to form a first liquid-gas mixture which can be channelled from a first outlet of the first mixing device into a connecting line coupled thereto; a container, which contains a container liquid, a second mixing device, which is arranged in the container and is surrounded by the container liquid, wherein the second mixing device comprises a suction opening in order to suction in the container liquid present in the region of the suction opening, wherein the second mixing device is connected to the connecting line and is designed to channel the first liquid-gas mixture and the suctioned container liquid into a constricted zone of the second mixing device so that the suctioned container liquid mixes with the first liquid-gas mixture and is thus able to form a second liquid-gas mixture, wherein the second mixing device has a second outlet out of which the second liquid-gas mixture is able to flow and mix with the container liquid present in the region of the second outlet, and a container outlet line, which is designed to feed the container liquid present there to the etching material provided in an etching module.