Etching Apparatus Actuator Control via Optical Emission Spectrometry
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Solution Overview
Problem
Existing etching processes in semiconductor manufacturing face challenges in accurately calculating actuator values for Run-to-Run control, leading to difficulties in stabilizing optical emission intensities and achieving consistent etching performance due to complex relationships between actuator values and optical emission spectra.
Innovation Solution
An etching apparatus with an optical emission spectrometry system that uses a control model to adjust actuator values based on optical emission intensity variations, employing both matrix and ratio-constraint models to calculate optimal actuator settings, thereby stabilizing optical emission intensities and improving etching process control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional control methods are used to calculate actuator values, then the control process is simpler, but the accuracy of optical emission intensity control deteriorates
Solution Approach 1:
The patent transforms the control problem from directly controlling actuator values to controlling optical emission intensity parameters. By using optical emission intensity as the controlled parameter and establishing its relationship with actuator values through control models (matrix model or ratio-constraint model), the system achieves higher control accuracy while managing complexity through parameter transformation rather than direct actuator control.
Solution Approach 2:
The patent introduces optical emission intensity as an intermediary parameter between actuators and etching process outcomes. Instead of directly calculating actuator values from process requirements, the system first determines target optical emission intensities, then uses control models to translate these into actuator values. This intermediary approach improves control precision by adding a measurable, controllable parameter layer.
2Manufacturing precision
If multiple actuator values are adjusted simultaneously, then the etching performance can be optimized, but the calculation complexity and control difficulty increase
Solution Approach 1:
The patent segments the control of multiple actuators into manageable components by establishing individual relationships between each actuator and optical emission intensity. The control model breaks down the complex multi-variable control problem into separate calculation pathways, where each actuator's contribution to optical emission intensity is modeled independently, then integrated to determine optimal actuator values. This segmentation makes multi-actuator control more tractable.
Solution Approach 2:
The patent implements dynamic control by continuously monitoring optical emission intensity during the etching process and adjusting actuator values in real-time based on deviations from target values. The control system adapts actuator settings dynamically rather than using fixed predetermined values, allowing the system to maintain optimal etching performance despite process variations while managing complexity through feedback-driven adjustment.
3Reliability
If Run-to-Run control is implemented to stabilize optical emission intensity, then the etching performance improves, but the control process time and complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing control models that define the relationships between actuators and optical emission intensity before the actual etching process. Target optical emission intensity values are determined in advance based on process requirements. During Run-to-Run control, the system only needs to calculate deviations from these predetermined targets and make corrective adjustments, rather than performing complex optimization calculations in real-time. This preliminary preparation significantly reduces control process time while maintaining stability.
4Measurement precision
If optical emission intensity is used as the control target, then the etching performance can be monitored in real-time, but the complexity of determining target values and calculating actuator values increases
Solution Approach 1:
The patent implements feedback control by continuously measuring optical emission intensity during the etching process and using this information to adjust actuator values. The system compares actual optical emission intensity readings against target values, calculates deviations, and determines corrective actuator adjustments based on pre-established control models. This feedback mechanism enables real-time monitoring and control while managing complexity through the use of predetermined model relationships rather than requiring complex real-time optimization algorithms.
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
The solution enables precise adjustment of actuator values, reducing errors in optical emission intensity targets and improving the consistency of etching performance, while also simplifying the evaluation of control performance through simulation methods.
Implementation Method 1
an apparatus (OES, etc.) that monitors plasma optical emission
Implementation Method 2
a gas is ionized and dissociated using plasma to cause a dissociated substance to act on a wafer
Implementation Method 3
a gas is ionized and dissociated using plasma
Data Source
AI summary
Based on a model for determining optical emission intensity values Y at wavelengths from actuator values X of an etching apparatus, X is calculated from Y to achieve preferable Run-to-Run control over Y. A relation between X and Y is defined as a control model (matrix model C1, ratio-constraint model C2) based on an algebraical expression with ΔX as an input and ΔY as an output. In etching process control, ΔX (manipulated volume) is calculated from ΔY (controlled volume) using the control model, based on a non-control optical emission intensity value Y, to set X (S1) for the etching process, during which Y is monitored. Based on an actual value for Y, a non-control optical emission intensity value Y to be used in the next wafer etching process is calculated.