Plasma Reactor Control via ML Latent State Representation

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Solution Overview

Problem

The processing of wafers for micro- and nano-scale devices is challenging due to high variability in plasma reactors, leading to inconsistent product quality, waste, and inefficiencies in existing control strategies that rely on time-consuming and costly metrology analyses.

Innovation Solution

A computer-implemented method using a trained machine learning model that receives real-time sensor data from multiple sensors to generate a latent representation of the plasma state, allowing for immediate adjustments to control parameters in the plasma reactor, thereby reducing process variability and improving product uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If non-invasive measurement techniques are used to monitor plasma state, then plasma contamination is avoided, but specific information such as plasma density cannot be obtained

Engineering Contradiction:
Improveplasma contaminationVSAvoidplasma density information
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent introduces optical emission spectroscopy as an intermediary measurement technique that allows indirect observation of plasma properties without physical contact. By analyzing the spectral characteristics of light emitted by the plasma, the system can derive plasma density and other parameters while maintaining the non-invasive advantage of not contaminating the plasma with physical probes

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical/invasive probe-based measurement systems with optical measurement systems. Instead of using physical probes that interact directly with the plasma, the system uses optical emission spectroscopy to measure plasma properties remotely through light interaction, thereby eliminating contamination while preserving measurement capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If detailed metrology analysis is performed on each wafer batch, then process quality is improved, but production time increases significantly

Engineering Contradiction:
Improvewafer qualityVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary real-time monitoring and analysis during the wafer fabrication process itself, rather than waiting until after batch completion. By continuously monitoring plasma parameters and wafer properties during processing, the system can identify quality issues early and make immediate adjustments, eliminating the need for time-consuming post-processing metrology analysis

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback control system where real-time measurements of plasma state and wafer properties are continuously fed back to the control system. This enables dynamic adjustment of processing parameters during fabrication to maintain optimal quality, replacing the static post-batch analysis approach with an active continuous improvement loop that reduces both time and waste

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If real-time control of plasma reactor parameters is implemented, then product consistency is improved, but system complexity increases

Engineering Contradiction:
Improveproduct consistencyVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a machine learning model that serves multiple functions simultaneously: it processes data from multiple sensors, identifies plasma state, predicts wafer properties, and generates control recommendations. This multi-functional approach consolidates what would otherwise require separate specialized systems into a single unified platform, managing complexity while maintaining comprehensive real-time control capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent transforms complex multi-parameter plasma control into a simplified process by using the machine learning model to identify the critical subset of parameters that most influence product quality. The system dynamically adjusts these key parameters in real-time based on learned relationships, rather than attempting to control all possible parameters equally, thereby achieving effective control with managed complexity

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20230245872A1Control of Processing Equipment
Publication Date: 2023.08.03 UNIV OF EXETER
  • US20230245872A1 patent drawing
  • US20230245872A1 patent drawing
  • US20230245872A1 patent drawing

AI summary

Broadly speaking, the present techniques provide a method and system for controlling a wafer production process in real-time using a trained machine learning, ML, model. Advantageously, the ML model uses multiple sensed parameters to determine a state of a plasma used in the wafer production process, and this can be used to adjust at least one control parameter of a plasma reactor used in the wafer production process to reduce process variability.