Microwave Plasma Pulsing to Limit Ion Damage in Processing
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Solution Overview
Problem
In plasma processing, the continuous supply of microwave energy can lead to increased electron temperature near the electromagnetic wave radiation port, causing damage due to ion impacts, as the energy concentration results in self-bias and ion acceleration.
Innovation Solution
The method involves intermittently supplying microwave powers from multiple microwave introducing modules, with periodic OFF-states to control the plasma electron temperature, maintaining electron density while reducing damage by synchronizing or asynchronously controlling the ON and OFF timings of microwave pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If microwave energy is continuously supplied to generate plasma, then plasma electron density is maintained, but plasma electron temperature increases causing ion impact damage
Solution Approach 1:
The patent applies periodic action by intermittently supplying microwave power in pulsed cycles rather than continuously. The microwave power is supplied for a predetermined period to generate plasma, then stopped to allow electron temperature to decrease, preventing ion impact damage while maintaining plasma electron density through repeated cycling.
Solution Approach 2:
The patent applies dynamics by dynamically adjusting the microwave power supply timing and duration based on plasma conditions. The supply period and stop period are controlled to optimize plasma generation while preventing excessive electron temperature rise, adapting the power supply regime to maintain effective cleaning without damage.
2Object-affected harmful factors
If microwave power is intermittently supplied to reduce electron temperature, then ion impact damage is reduced, but plasma generation efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by using periodic microwave power supply with optimized duty cycles. The plasma is generated during the supply period for cleaning effectiveness, then the power is stopped during the stop period to reduce electron temperature and prevent damage, achieving both goals through temporal separation of functions.
Solution Approach 2:
The patent applies parameter changes by adjusting the microwave power supply timing parameters (supply period duration, stop period duration, duty cycle) to optimize the balance between plasma generation efficiency and electron temperature control, thereby maintaining productivity while reducing ion impact damage.
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 lowers the plasma electron temperature while maintaining electron density, thereby reducing ion-induced damage during cleaning and other plasma processing operations.
Implementation Method 1
supplying microwave powers output from a plurality of microwave introducing modules into the processing container
Implementation Method 2
Electromagnetic wave energy is concentrated in the vicinity of an electromagnetic wave radiation port
Implementation Method 3
the cleaning processing is executed by the chemical action of radicals in the plasma
Data Source
AI summary
A plasma processing method includes: supplying a gas into a processing container; and intermittently supplying microwave powers output from a plurality of microwave introducing modules into the processing container. In the intermittently supplying the microwave powers, the supply of all the microwave powers from the plurality of microwave introducing modules is periodically in an OFF state for a given time.