Gas Analyzer Ion Path Blocking for Plasma Light Noise Removal
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Solution Overview
Problem
Current gas analyzing apparatuses face challenges in reducing noise interference, particularly from plasma light, which affects the accuracy of ion detection in semiconductor processes, due to the difficulty in completely blocking stray light with existing light shielding methods.
Innovation Solution
The apparatus employs a non-linear ion path to guide ions from the ionization device to the analyzer, combined with an energy filter that intermittently blocks and releases the ion flow using an electric or magnetic field, allowing for the acquisition of detection data with and without ion flow blockage, enabling the subtraction of noise components from the measurement results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a non-linear ion path is used to guide ions from the ionization device to the analyzer, then the influence of light that produces noise at the analyzer is suppressed, but it is impossible to completely block stray light, so part of the light generated during ionization can reach the analyzer due to leakage or stray light and become a source of noise
Solution Approach 1:
The patent applies preliminary action by performing a background measurement before the actual ion analysis. The blocking device is activated to block the ion flow while allowing light to pass through, capturing the noise signal from plasma light and stray light. This background signal is then subtracted from the total measurement signal to eliminate the harmful light interference, thereby improving measurement precision without compromising the noise suppression effect of the non-linear ion path.
Solution Approach 2:
The patent implements feedback by using the background measurement signal to correct the main measurement signal. The noise components captured during the background measurement phase are fed back into the system and subtracted from the total measurement, creating a corrected signal that has the light interference removed. This feedback mechanism allows the system to dynamically compensate for stray light effects and maintain high measurement accuracy.
2Measurement precision
If a blocking device is added to intermittently block and release the ion flow, then noise components can be separated from measurement signals, but the device complexity increases
Solution Approach 1:
The blocking device is designed with multi-functionality, serving both as an ion flow blocker and as a measurement mode switch. The same device structure is used to create different measurement conditions (blocked vs. unblocked ion flow), eliminating the need for separate components for each function. This universal approach reduces overall device complexity while still achieving the noise reduction goal through differential measurements.
Solution Approach 2:
The blocking device operates periodically, alternating between blocking and unblocking the ion flow in a cyclic manner. This periodic action allows the system to collect background signals during blocked phases and sample signals during unblocked phases, then process these alternating measurements to extract the actual ion signal with noise removed. The periodic operation simplifies the control logic and timing mechanisms required compared to continuous variable control.
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 noise interference, resulting in highly accurate measurement results by suppressing the influence of stray light and improving the overall precision of gas analysis, particularly in harsh semiconductor manufacturing environments.
Implementation Method 1
a blocking device that intermittently blocks and releases, using an electric field or a magnetic field, the ion flow on at least part of a path of the ion flow
Implementation Method 2
The ionization device may include a device that plasma-ionizes the sample gas
Data Source
AI summary
A gas analyzing apparatus includes: an ionization device that generates an ion flow of a sample gas; an analyzer that analyzes the ion flow supplied from the ionization device; a first ion path that non-linearly guides the ion flow from the ionization device to an inlet of the analyzer; and a blocking device for intermittently blocking and releasing, using an electric field or a magnetic field, the ion flow on at least part of a path of the ion flow through the first ion path to a mass filter of the analyzer. It is possible to perform measurement in a state where the ion flow is blocked and measurement in a state where the ion flow is not blocked.