ALD Conductance Valve Pressure Stabilization via Reference Opening
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Solution Overview
Problem
The Atomic Layer Deposition (ALD) method faces challenges in maintaining stable processing pressure due to frequent changes in reactive gas supply and plasma operation, leading to unstable pressure control and potential issues with valve flutter, reduced versatility, and increased maintenance needs due to aging variations and installation conditions.
Innovation Solution
A thin film formation method and apparatus that uses a conductance valve with a reference valve opening level determined before film formation, maintaining this level throughout the process to stabilize pressure, independent of installation conditions or aging variations, by employing a predetermined gas flow during preparation and maintaining the valve opening level using an automatic pressure control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If APC (Automatic Pressure Control) is employed in ALD method, then pressure control is automated, but pressure becomes unstable due to valve flutter caused by frequent gas supply changes
Solution Approach 1:
The patent applies preliminary action by determining the reference valve opening level before the ALD process begins. This reference value is established in advance and then maintained throughout the process, preventing the valve flutter that would occur with continuous APC adjustments during frequent gas supply changes.
Solution Approach 2:
The patent transitions from a static reference valve opening level determination to a dynamic control strategy where the valve opening level is maintained at the predetermined reference value throughout the ALD process, adapting to different process conditions while ensuring pressure stability.
2Reliability
If reference valve opening level is determined before film formation, then pressure stability is improved, but adaptability to aging variations and installation conditions decreases
Solution Approach 1:
The patent employs feedback by measuring the actual pressure during the preparation period and using this information to determine the reference valve opening level. This feedback mechanism ensures that the reference value is optimized for the specific installation conditions and accounts for any aging variations, thereby maintaining both pressure stability and adaptability.
Solution Approach 2:
The patent changes the parameter of valve opening level from a fixed predetermined value to a dynamically determined reference value based on actual pressure measurements. This parameter change allows the system to adapt to different installation conditions and aging variations while maintaining pressure stability during the ALD process.
3Speed
If conductance valve is frequently adjusted during ALD cycles, then pressure control responsiveness is improved, but valve flutter increases causing instability
Solution Approach 1:
The patent applies preliminary action by determining the reference valve opening level before the ALD process begins. This reference value is established in advance and then maintained throughout the process, preventing the valve flutter that would occur with continuous APC adjustments during frequent gas supply changes.
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 ensures stable pressure control and reproducibility in ALD processes without changing the processing recipe, enhancing the versatility and reducing downtime due to aging variations, making it suitable for mass production lines.
Implementation Method 1
maintaining a reference valve opening level of the conductance valve, which exhausts the inside of a processing chamber, thereby stabilizing pressure in the processing chamber
Implementation Method 2
a conductance valve 22 on an exhaust path 18 connecting the processing chamber 10 and a vacuum pump 20
Implementation Method 3
in the ALD method, two types of reactive gas are alternately and intermittently supplied into the processing chamber at time intervals of a few seconds with purge gas supplied between the two types of reactive gas, and a layer or one atom or one molecule is formed in one cycle due to a chemical reaction of both reactive gasses
Implementation Method 4
in a PEALD (Plasma Enhanced Atomic Layer Deposition) method in which one of the two types of reactive gas is enhanced (excited) with plasma in the processing chamber to generate a reactive species
Data Source
AI summary
A thin film formation method is used for forming a thin film by providing a conductance valve on an exhaust path connecting a depressurizable processing chamber and a vacuum pump, arranging a processing object substrate inside the processing chamber, performing once or plural times a cycle including a first step of supplying a first reactive gas and a second step of supplying a second reactive gas into the processing chamber during a film formation processing period to cause a chemical reaction between the first reactive gas and the second reactive gas, and using the chemical reaction to form the thin film on the substrate. The thin film formation method includes a first process of supplying into the processing chamber a predetermined gas by a specified flow while exhausting the inside of the processing chamber, and determining a reference value that is equal to a valve opening level of the conductance valve causing pressure inside the processing chamber to substantially match a specified value, the first process being performed during a preparation period before the film formation processing period starts; and a second process of maintaining the valve opening level of the conductance valve at the reference value at least during the first step and the second step of the cycle performed during the film formation processing period.