Etching Method for 3D-NAND Floating Electrode Arcing
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Solution Overview
Problem
The challenge in manufacturing 3D-NAND type flash memory is the occurrence of arcing due to a potential difference between the floating electrode and the conductive layer, which can damage the peripheral circuit during the etching process, while reducing power to prevent arcing compromises the desired etching characteristics.
Innovation Solution
An etching method that supplies a first high frequency electric power as a continuous wave and a second high frequency electric power as a pulse wave with a duty cycle of 20% or less, applied to the silicon-containing film on a floating potential electrode, to reduce arcing and maintain desired etching characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power is reduced to suppress arcing, then arcing occurrence is reduced, but etching rate deteriorates
Solution Approach 1:
The patent applies periodic action by switching the second high frequency electric power between ON and OFF states in a cyclic manner. During the ON period, etching proceeds normally; during the OFF period, charged particles are discharged and arcing is suppressed. This periodic modulation allows the system to achieve both high etching rate and arcing suppression, resolving the technical contradiction between productivity and reliability.
2Reliability
If power is reduced to suppress arcing, then peripheral circuit safety is improved, but etching characteristic deteriorates
Solution Approach 1:
By periodically switching the second high frequency electric power, the patent maintains safe operating conditions for peripheral circuits while preserving etching characteristics. The periodic OFF state allows charge discharge to prevent arcing damage, while the ON state maintains etching performance, thus resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent employs dynamics by making the power supply state changeable rather than fixed. The second high frequency electric power is dynamically switched between ON and OFF based on process requirements, allowing the system to adapt between protecting peripheral circuits and maintaining etching characteristics, thereby resolving the technical contradiction.
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 arcing occurrences while maintaining a desirable etching rate and selectivity, ensuring the integrity of the peripheral circuit during the etching process.
Implementation Method 1
The etching is performed in a processing vessel while supplying gas, a first high frequency electric power of a first frequency, and a second high frequency electric power of a second frequency less than the first frequency
Implementation Method 2
a potential difference between the floating electrode 30 and the conductive layer 10 of a ground potential is caused, and arcing occurs because of an electron shading effect
Data Source
AI summary
A method of etching silicon-containing film formed on an electrode layer of a floating potential is provided. The etching is performed in a processing vessel while supplying gas, a first high frequency electric power of a first frequency, and a second high frequency electric power of a second frequency less than the first frequency. The method includes a step of supplying, during etching of the silicon-containing film, the first high frequency electric power as a continuous wave and the second high frequency electric power as a pulse wave having a duty cycle of 20% or less, upon a distance from the electrode layer to a bottom of an etching pattern formed on the silicon-containing film becoming not more than a predetermined distance.