Plasma Processing Apparatus Synchronization Control
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Solution Overview
Problem
Existing plasma processing technologies face challenges in achieving uniform etching rates and controlling ion energy distribution, particularly in polycrystalline silicon layers, due to the lack of effective synchronization of radio-frequency power with bias power cycles.
Innovation Solution
A plasma processing apparatus with a controller that alternately applies source power in synchronization with the high-frequency cycle of bias power, specifically turning OFF the source power at the negative side peak of the phase within one cycle of a reference electrical state, to control ion energy distribution and plasma electron density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If radio-frequency power for drawing applied ions is applied in synchronization with ON/OFF of radio-frequency power for generating plasma, then ion delivery to substrate is improved, but control of ion energy distribution and plasma electron density becomes difficult
Solution Approach 1:
The patent applies periodic action by alternately turning ON and OFF the source power in synchronization with the bias power cycle. Specifically, the source power is turned OFF during the negative half-cycle of the bias power and turned ON during the positive half-cycle, creating a periodic control pattern that simultaneously improves ion delivery and maintains control over ion energy distribution and plasma electron density
Solution Approach 2:
The patent changes the timing parameter of source power application relative to the bias power cycle. By synchronizing the source power ON/OFF timing with specific phases of the bias power cycle (turning OFF at negative half-cycle, turning ON at positive half-cycle), the patent independently controls both ion delivery and ion energy distribution without increasing system complexity
2Quantity of substance
If source power is continuously applied, then plasma electron density is maintained, but ion energy distribution becomes uncontrolled and tilting occurs
Solution Approach 1:
The patent applies periodic action by pulsing the source power in synchronization with the bias power cycle. The source power is turned OFF during the negative half-cycle and turned ON during the positive half-cycle, creating periodic variations that control ion energy distribution while maintaining adequate plasma electron density through timed application
Solution Approach 2:
The patent applies preliminary action by turning ON the source power before the ion acceleration phase (during the positive half-cycle of bias power) and turning it OFF before the ion bombardment phase (during the negative half-cycle). This timing ensures that plasma electrons are generated in advance while preventing excessive ion energy that would cause tilting
3Productivity
If source power is turned OFF during negative half-cycle of bias power, then high-energy ion delivery is increased, but etching rate uniformity may be affected
Solution Approach 1:
The patent changes the timing parameter of source power application to turn OFF during the negative half-cycle of bias power, which increases high-energy ion delivery. However, it maintains etching uniformity by turning ON the source power during the positive half-cycle, which replenishes plasma electrons and ensures consistent etching conditions across the substrate surface
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 enables independent control of ion energy and plasma electron density, resulting in improved uniformity and efficiency of the etching process, with increased high-energy ion delivery and reduced tilting in etched shapes.
Implementation Method 1
a plasma generation source that generates plasma
Implementation Method 2
a radio-frequency power for generating plasma is applied in synchronization with ON/OFF of a radio-frequency power
Implementation Method 3
a bias power supply that supplies a bias power to the first electrode... cause the ions to reach a polycrystalline silicon layer
Data Source
AI summary
A plasma processing apparatus includes: a first electrode on which a substrate is placed; a plasma generation source that generates plasma; a bias power supply that supplies bias power to the first electrode; a source power supply that supplies source power to the plasma generation source; and a controller. The controller performs a control such that a first state and a second state of the source power are alternately applied in synchronization with a high frequency cycle of the bias power, or a phase within one cycle of a reference electrical state indicating any one of a voltage, a current and an electromagnetic field measured in a power feed system of the bias power, and performs a control to turn OFF the source power at least at a negative side peak of the phase within one cycle of the reference electrical state.