Time-Modulated Antenna Power for Plasma Etching Magnetic Films
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Solution Overview
Problem
The challenge in plasma etching of magnetic films using CO gas is the dissociation of CO in the plasma, which reduces the efficiency of the etching process due to the deposition of carbon on the film, and existing methods that spatially separate plasma regions struggle to effectively suppress dissociation.
Innovation Solution
A plasma etching method where the power applied to the antenna is time-modulated, synchronizing the feeding of plasma generating gas and CO gas to suppress dissociation by feeding CO when the antenna power is low and plasma generating gas when it's high, ensuring the electron temperature remains low to generate active species for efficient etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CO gas is fed to the plasma region to etch the magnetic film, then the etching reaction is promoted, but CO dissociation occurs and carbon is deposited on the film inhibiting etching
Solution Approach 1:
The patent applies periodic action by time-modulating the antenna power and gas feeding in a cyclic manner. During the plasma generation period, plasma-generating gas is fed to create high-density plasma. During the etching period, CO gas is fed while antenna power is reduced or stopped, allowing CO to react with the magnetic film without significant dissociation. This periodic switching resolves the contradiction by separating the plasma generation function from the etching function in time, preventing carbon deposition while maintaining etching efficiency.
Solution Approach 2:
The patent employs dynamics by making the antenna power and gas feeding conditions variable rather than static. The antenna power is dynamically adjusted between high power (for plasma generation) and low or zero power (for etching). The gas feeding is dynamically switched between plasma-generating gas and CO gas based on the operational phase. This dynamic control allows the system to optimize for either plasma density or etching reaction at different times, resolving the contradiction between promoting etching and preventing carbon deposition.
2Quantity of substance
If antenna power is increased to generate high density plasma, then plasma density is improved, but electron temperature increases causing CO dissociation
Solution Approach 1:
The patent uses periodic action to separate the high plasma density state from the high electron temperature state. During the plasma generation period, high antenna power creates high plasma density. During the etching period, antenna power is reduced or stopped, allowing electron temperature to decrease while CO gas is fed for etching. This temporal separation resolves the contradiction by ensuring high plasma density during plasma generation and low electron temperature during etching.
Solution Approach 2:
The patent applies preliminary action by generating the plasma and achieving high plasma density before feeding CO gas for etching. The plasma is pre-generated using plasma-generating gas during a dedicated plasma generation period, and only after this is established does the system switch to CO gas feeding for etching. This preliminary plasma generation ensures sufficient plasma density is present before introducing CO, while the subsequent reduction in antenna power prevents CO dissociation during the etching phase.
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 suppresses CO dissociation, allowing for high-efficiency etching of magnetic films by maintaining a suitable plasma state for promoting reactions between the film and CO, thereby improving the processing efficiency and reducing corrosion risks.
Implementation Method 1
plasma generating gas for generating plasma and a gas containing C and O, wherein a power applied to an antenna for generating plasma is subjected to time modulation
Implementation Method 2
a power applied to an antenna for generating plasma is subjected to time modulation... ensuring the electron temperature remains low to generate active species for efficient etching
Implementation Method 3
generate an active species of CO so as to promote the reaction between the magnetic film and the CO... promote the reaction between the film and CO
Data Source
AI summary
In processing a magnetic film composed for example of Fe, Co or Ni formed on a substrate and a nonvolatile metal containing the same in a vacuum reactor using a plasma generating gas for generating plasma and a gas containing C and O, a power applied to an antenna for generating plasma is time-modulated, wherein the feeding of gas containing C and O to the vacuum reactor is synchronized with the time-modulated antenna power so that the supply of gas containing C and O to the vacuum reactor is suppressed when the antenna power is high and the gas containing C and O is fed to the vacuum reactor when the antenna power is low.