Local Plasma Source for Vacuum Chamber Partial Pressure Mapping
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Solution Overview
Problem
Conventional partial pressure measuring methods in vacuum chambers face challenges such as high costs, long measurement times, and inaccurate readings due to the use of plasma emission from process plasma sources, which also measure non-target gas emissions, and require complex optical system adjustments, making them unsuitable for mass production processes.
Innovation Solution
A partial pressure measuring method and apparatus that utilize a local plasma source dedicated to measurement, which can be moved to desired locations within the vacuum chamber, generating plasma for emission spectral analysis through a window, allowing for accurate and efficient measurement of partial pressure distribution without interfering with the process plasma source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mass analyzer with a pipe is used to measure partial pressure, then the measurement can be performed, but the pipe radius must be short which lowers conductance and affects measurement accuracy
Solution Approach 1:
The invention extracts the measurement function from the process plasma source and implements it in a dedicated local plasma source. This separation allows the measurement system to be optimized independently, using a local plasma source positioned close to the measurement location without requiring long pipes, thereby maintaining both high conductance and measurement accuracy.
Solution Approach 2:
The invention introduces a local plasma source as an intermediary between the vacuum chamber environment and the measurement system. This local plasma source generates plasma locally at the measurement position, allowing direct spectral analysis without needing to transport gas through pipes, thus eliminating the conductance limitation while maintaining measurement reliability.
2Device complexity
If a spectroscopic measuring apparatus with laser unit and spectroscope is used, then partial pressure can be measured without pipes, but the apparatus is expensive and requires long measurement time
Solution Approach 1:
The invention employs a local plasma source that generates its own plasma and emission spectrum directly at the measurement location. The system uses the plasma emission from the local source itself for measurement, eliminating the need for external laser excitation and complex optical systems, thereby reducing both cost and measurement time while maintaining accuracy.
Solution Approach 2:
The invention replaces the complex mechanical optical system (laser unit, spectroscope, optical fibers) with a simpler plasma-based measurement approach. By using the natural emission spectrum from the local plasma source, the system eliminates the need for expensive and time-consuming laser-induced fluorescence equipment while achieving the same measurement objective.
3Measurement precision
If conventional spectroscopic apparatus is used, then partial pressure can be measured, but optical systems need to be moved and adjusted for each location which reduces productivity
Solution Approach 1:
The invention makes the plasma source movable rather than moving the complex optical system. The local plasma source can be easily repositioned to different locations within the vacuum chamber, allowing rapid measurement at multiple positions without the time-consuming adjustment of optical components, thereby significantly improving measurement productivity while maintaining spatial resolution.
4Ease of manufacture
If process plasma source emission is used for measurement, then measurement can be performed, but non-target gas emissions are also measured reducing accuracy
Solution Approach 1:
The invention extracts the measurement function from the process plasma source and implements it in a dedicated local plasma source. This separation allows the measurement system to be optimized independently, using a local plasma source positioned close to the measurement location without requiring long pipes, thereby maintaining both high conductance and measurement accuracy.
Solution Approach 2:
The invention creates a localized plasma source with specific properties tailored for measurement purposes. The local plasma source is designed to generate plasma with emission characteristics suitable for the target gas measurement, allowing selective and accurate measurement of specific gas species without interference from other gases present in the vacuum chamber.
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
Enables precise and cost-effective measurement of partial pressure distribution in vacuum chambers, allowing for homogeneous film formation by adjusting process parameters based on measured data, without the need for complex equipment and with reduced noise and increased accuracy.
Implementation Method 1
measuring a partial pressure distribution in the vacuum chamber by (i) receiving, through a window, emission of plasma generated by the local plasma source
Implementation Method 2
a local plasma source 9; an electrode 9a for the local plasma source 9; a power source 10a for the local plasma source 9
Implementation Method 3
performing emission spectral analysis on intensity of the emission
Data Source
AI summary
Provided is a partial pressure measuring method and a partial pressure measuring apparatus by which a partial pressure distribution is easily measured in a vacuum chamber. The partial pressure measuring method and the partial pressure measuring apparatus includes: moving a local plasma source dedicated to partial pressure measuring provided in the vacuum chamber, to a location at which the measuring is to be performed; and measuring a partial pressure distribution in the vacuum chamber, by receiving emission of plasma generated by the local plasma source through a window which is formed in a wall part of the vacuum chamber and through which the emission passes, and thereby performing emission spectral analysis on intensity of the emission.