RF Power Spike for Plasma Ignition Stability in PEALD
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Solution Overview
Problem
In plasma-enhanced atomic layer deposition (PEALD) processes, high RF power can lead to issues like dopant implantation, oxidation of underlying layers, and etching or corrosion of photoresists, while low RF power results in plasma ignition failure and processing inconsistencies due to power loss and sensitivity to environmental changes.
Innovation Solution
Applying a spike of RF power from zero to a higher spike power and then dropping to a base power near the firing voltage, with the spike duration being substantially shorter than the continuous base power application, to stabilize plasma ignition without causing significant changes to the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high RF power is applied, then film quality is improved, but dopant implantation occurs and underlying layers are oxidized and photoresist is etched
Solution Approach 1:
The patent applies periodic pulsed RF power instead of continuous RF power. A high-power pulse is applied for a short duration to initiate plasma ignition and achieve desired film quality, then the power is reduced to a low base level to prevent harmful effects like dopant implantation, oxidation, and etching during the remainder of the deposition cycle.
Solution Approach 2:
The high RF power pulse is applied preliminarily at the beginning of the process to establish plasma ignition and achieve the necessary film quality characteristics, before reducing to the low base power that prevents harmful side effects during the main deposition phase.
2Object-affected harmful factors
If low RF power is applied, then harmful effects are avoided, but plasma ignition failure occurs and processing becomes inconsistent
Solution Approach 1:
The system uses periodic pulsed RF power where a high-power pulse is applied intermittently to ensure reliable plasma ignition, while the majority of the time the system operates at low base power to avoid harmful effects. This periodic high-power intervention ensures ignition reliability without compromising substrate integrity.
Solution Approach 2:
The RF power parameter is dynamically changed between two states: a high power level for brief periods to ensure ignition and a low base power level for the majority of the process. This parameter switching allows the system to achieve both reliable ignition and avoidance of harmful effects.
3Object-affected harmful factors
If low base power is used to avoid damage, then substrate integrity is maintained, but plasma ignition becomes unstable
Solution Approach 1:
The system employs periodic high-power pulses superimposed on a low base power. The low base power maintains substrate integrity by preventing damage, while the periodic high-power pulses provide the necessary energy bursts to stabilize plasma ignition and ensure consistent plasma formation.
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 significantly reduces plasma ignition failure while maintaining film quality, as the spike power improves ignition reliability without causing substantial damage to the substrate, even when the base power is set near the threshold for ignition failure.
Implementation Method 1
applying a spike of RF power between an upper electrode and a lower electrode on which a substrate is placed, wherein the spike starts from zero power, jumps to a spike power, and then drops to a base power that is so low as to cause plasma ignition failure
Data Source
AI summary
A method for stabilizing plasma ignition in a continuous process conducted on a substrate, includes: applying a spike of RF power between an upper electrode and a lower electrode on which the substrate is placed, wherein the spike starts from zero power, jumps to a spike power, and then drops to a base power which is so low as to cause plasma ignition failure; and continuously applying RF power at the base power between the upper and lower electrode for a duration substantially longer than a duration of the spike to process the substrate. The spike is such that ignition failure is reduced.