Plasma Arc Detection via Signal Path Deviation

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Solution Overview

Problem

Existing methods for identifying arcs in plasma processes with periodically changing output signals are slow and prone to false identifications, particularly in semiconductor production where rapid and reliable detection is crucial.

Innovation Solution

A monitoring device and method that detect signal paths within specific time ranges and generate identification signals based on minimum time and signal amplitude differences, establishing a threshold value line to reliably identify arcs in plasma processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the effective value of current and voltage is established over multiple periods to identify arcs, then the identification is more reliable, but the response time becomes too slow (hundreds of milliseconds)

Engineering Contradiction:

Improvearc identification reliabilityVSAvoidarc identification response time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent pre-calculates and stores reference values during a calibration phase before actual arc detection begins. These reference values represent normal operating conditions and are prepared in advance, allowing the system to perform rapid comparisons during operation without needing to accumulate multiple periods of data, thus achieving fast response while maintaining reliability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent divides the arc detection process into two distinct phases: a calibration phase for establishing reference values, and a detection phase for comparing actual signals against these references. This segmentation allows the system to prepare necessary data structures in advance and then perform rapid comparisons during actual operation, resolving the contradiction between reliability and speed

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If multiple reference values and tolerances are set for arc identification, then the identification accuracy improves, but the device complexity increases

Engineering Contradiction:

Improvearc identification accuracyVSAvoidreference value and tolerance configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies a single tolerance threshold that is deliberately set to be more restrictive than strictly necessary. Instead of using multiple reference values with individual tolerances, the system uses one reference value with a tighter tolerance, simplifying the configuration while maintaining or improving identification accuracy through the stricter single threshold

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10181392B2Monitoring a discharge in a plasma process

Publication Date: 2019.01.15 TRUMPF PATENTABTEILUNG

AI summary

Devices and methods for monitoring a discharge in a plasma process are provided. An example method includes detecting at least a first signal path of at least one plasma supply signal within at least a first time range within at least one period of the plasma supply signal, detecting at least a second signal path of the at least one plasma supply signal within at least a second time range which is at the point corresponding to the first time range in at least one other period of the plasma supply signal, and generating an identification signal if the second signal path deviates by at least a distance from the first signal path. The distance has a minimum time difference and a minimum signal amplitude difference. The method enables to identify arcs in a very reliable and very rapid manner.