Sputter Gas Oxygen Control for ITO Film Uniformity
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Solution Overview
Problem
The existing film formation processes for transparent conductive oxidized films, such as ITO, face issues with non-uniform quality and increased resistance due to excessive oxygen in the chamber, leading to defective products when the film formation process is repeated, as material sticks to the chamber walls and produces outgas, altering the oxygen partial pressure.
Innovation Solution
A film formation apparatus that includes a sealed container with a gas discharging unit to achieve base pressure and a sputter gas introducing unit that adjusts the oxygen partial pressure based on the increasing base pressure from sticking material, using a control unit to determine and control the oxygen partial pressure to maintain optimal conditions, preventing excessive oxygen accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the film formation process is repeatedly executed, then the productivity increases, but the oxygen partial pressure in the chamber increases due to outgas from sticking material, causing non-uniform film quality and increased resistance
Solution Approach 1:
The patent applies preliminary action by performing a gas discharging operation before each film formation process to remove outgas accumulated from previous processes. This preliminary removal of oxygen-containing outgas prevents the oxygen partial pressure from increasing during subsequent film formation, thereby maintaining consistent film quality across multiple production cycles while enabling repeated execution of the film formation process
Solution Approach 2:
The patent implements feedback control by measuring the film formation speed and using this information to control the gas discharging operation. When the film formation speed decreases below a predetermined threshold, indicating that outgas accumulation has affected the process, the system automatically performs gas discharging to restore optimal conditions, ensuring consistent film quality while maintaining high productivity
2Manufacturing precision
If the film formation speed is monitored to adjust oxygen introduction, then the film quality can be maintained, but the oxygen amount is already excessive when adjustment is made, resulting in defective products
Solution Approach 1:
The patent applies preliminary action by performing gas discharging before the film formation process begins, rather than waiting until film formation speed decreases. This proactive removal of outgas prevents oxygen accumulation before it can affect film quality, ensuring that the oxygen partial pressure remains appropriate throughout the entire film formation process and preventing defective products
Solution Approach 2:
The patent skips the intermediate state where oxygen accumulation begins to affect film formation by performing rapid gas discharging at the start of each cycle. This approach rushes through the potential problem period before outgas accumulation can significantly impact film quality, ensuring consistent product reliability
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 consistent film quality with reduced variability and prevents resistance increases in the ITO film, maintaining the appropriate oxygen amount during repeated film formation processes, thereby producing high-quality films.
Implementation Method 1
a gas discharging unit discharging a gas in the sealed container for a predetermined time period after the workpiece is carried into the sealed container to obtain a base pressure
Implementation Method 2
a sputter gas introducing unit introducing a sputter gas containing oxygen to an interior of the sealed container having undergone the discharging and became the base pressure
Implementation Method 3
a DC voltage is applied to the target to obtain the plasma of the sputter gas and to produce ions, and the ions collide with the target. Material particles beaten out from the target are deposited on the workpiece
Implementation Method 4
The film formation material sticking to the internal wall of the chamber produces an outgas. This outgas contains oxygen, and this oxygen is also ionized by plasma
Data Source
AI summary
A film formation apparatus includes a chamber that is a sealed container in which a target formed of a film formation material is placed, and into which the workpiece is carried, a gas discharging unit discharging a gas in the sealed container for a predetermined time period after the workpiece is carried into the chamber to obtain a base pressure, and a sputter gas introducing unit introducing a sputter gas containing oxygen to the interior of the chamber having undergone the discharging and becoming the base pressure. The sputter gas introducing unit decreases an oxygen partial pressure in the sputter gas to be introduced in the chamber in accordance with an increase in the base pressure due to an increase of the film formation material sticking to the interior of the chamber.