Etching Magneto-Resistive Effect Elements Without Hydrogen
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing etching methods for manufacturing magneto-resistive effect elements, particularly those using plasma of hydrocarbon and inert gases, face challenges in suppressing the deterioration of magnetic characteristics due to the formation of carbon-containing deposits and the use of hydrogen, which can alter the multilayer films.
Innovation Solution
An etching method involving the generation of plasma using a first gas containing hydrocarbon and noble gases to etch the second multilayer film, followed by the use of a second gas without hydrogen, such as oxygen and noble gases, to remove carbon-containing deposits, thereby minimizing the alteration of the magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma of hydrocarbon gas and noble gas is used to etch the multilayer film, then etching capability is improved, but carbon-containing deposits are formed on the workpiece
Solution Approach 1:
The patent converts the harmful carbon-containing deposits into removable byproducts by introducing oxygen plasma in a subsequent processing step. The oxygen reacts with the carbon deposits to form volatile carbon monoxide or carbon dioxide, which are then evacuated from the chamber, effectively removing the harmful deposits while preserving the benefits of hydrocarbon-based etching.
Solution Approach 2:
The patent uses noble gas (such as argon or helium) as the inert component in the plasma mixture. The noble gas provides a chemically inert environment that enables effective etching through physical sputtering while minimizing unwanted chemical reactions and deposit formation on the workpiece surface.
2Object-generated harmful factors
If hydrogen gas is used to remove deposits, then deposit removal is improved, but magnetic characteristics of the magneto-resistive effect element deteriorate
Solution Approach 1:
The patent changes the chemical composition parameter of the plasma-generating gas from hydrogen-based to oxygen-based. By using oxygen gas instead of hydrogen gas to generate the cleaning plasma, the patent achieves effective deposit removal through oxidation reactions while avoiding hydrogen diffusion into the magnetic layers that would deteriorate their magnetic characteristics.
Solution Approach 2:
The patent converts the previously harmful oxygen (which could oxidize magnetic layers) into a beneficial cleaning agent by controlling the plasma parameters and timing. The oxygen plasma selectively removes carbon deposits through oxidation while the process parameters are optimized to prevent excessive oxidation of the magnetic layers, thus converting a potential harm into a benefit.
3Object-generated harmful factors
If alternating steps of hydrocarbon plasma generation and hydrogen plasma generation are used, then deposit formation is reduced, but process complexity increases
Solution Approach 1:
The patent simplifies the process by using oxygen gas (an inert atmosphere relative to the magnetic layers when properly controlled) instead of hydrogen gas for deposit removal. This single gas type (oxygen) serves both as the cleaning agent and maintains process simplicity, eliminating the need for alternating between hydrocarbon and hydrogen plasma steps.
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 method effectively reduces the deterioration of magnetic characteristics by preventing hydrogen interaction with the multilayer films and controlling oxidation, resulting in improved resistance values and MR ratios of the magneto-resistive effect elements.
Implementation Method 1
plasma of a first gas including a hydrocarbon gas and a noble gas is generated inside a chamber of a plasma processing apparatus to etch the second multilayer film
Implementation Method 2
Ions and radicals generated from the plasma are irradiated to the multilayer film. Thus, the multilayer film is etched.
Implementation Method 3
generating a plasma of a second gas including a gas containing carbon and oxygen, an oxygen gas and a noble gas and not containing hydrogen inside the chamber to remove a carbon-containing deposit
Implementation Method 4
generating a plasma of a second gas including a gas containing carbon and oxygen, an oxygen gas and a noble gas
Data Source
AI summary
There is provided an workpiece etching method executed in manufacturing a magneto-resistive effect element, the workpiece including first and second multilayer films, the first multilayer film including first and second magnetic layers and a tunnel barrier layer formed between the first and second magnetic layers, and the second multilayer film being a multilayer film constituting a pinning layer in the magneto-resistive effect element. The method includes: etching the first multilayer film; generating plasma of a first gas including hydrocarbon and noble gases inside a chamber of a plasma processing apparatus to etch the second multilayer film inside the chamber; and generating plasma of a second gas including gas containing carbon and oxygen, an oxygen gas and a noble gas and not containing hydrogen inside the chamber to remove a carbon-containing deposit formed on the workpiece in the generating the plasma of the first gas.