Substrate Processing Apparatus Optical Emission Control

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Solution Overview

Problem

The existing chemically oxide removal (COR) processing method for wafers lacks precise control over the etching amount of oxide films, leading to inconsistent results due to variations in processing time and Q-time, often resulting in over-etching and penetration through the film, making it difficult to accurately control the etching process.

Innovation Solution

A substrate processing method and apparatus that measures the luminous intensity of a specific wavelength in the plasma emission spectrum to determine the start of processing and sets the processing time accordingly, allowing for precise control of the etching amount by detecting the end point of incubation time and adjusting the processing time to ensure consistent etching results.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the processing time of the COR processing is set to be longer than the processing time required for etching the oxide film by the desired amount, then the oxide film can be reliably etched by the desired amount, but the etching amount of the oxide film may exceed the desired amount and the oxide film may be etched more than required

Engineering Contradiction:

Improvereliability of etching the oxide film by the desired amountVSAvoidaccuracy of etching amount control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs optical emission spectroscopy to monitor the plasma state during COR processing in real-time. By measuring the luminous intensity of specific wavelengths corresponding to reaction products, the system provides feedback on the etching progress, allowing dynamic adjustment of processing parameters to achieve precise etching control without exceeding the desired amount.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the monitoring parameter from simple time-based control to optical emission intensity-based control. By detecting the luminous intensity of specific wavelengths in the plasma emission spectrum, the system can identify the endpoint of the incubation period and the start of actual etching, enabling precise control of etching duration and amount.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the processing time of the COR processing is set to be longer than the processing time required for etching the oxide film by the desired amount, then the oxide film can be reliably etched by the desired amount, but the processing time is extended beyond what is actually needed

Engineering Contradiction:

Improvereliability of etching the oxide film by the desired amountVSAvoidprocessing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Real-time optical monitoring provides feedback on the actual etching progress, allowing the process to be terminated as soon as the desired etching amount is achieved, rather than requiring a fixed extended processing time to account for variability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces time-based mechanical control with optical detection-based control. By using optical emission spectroscopy to detect the start of actual etching, the system eliminates the need for conservative time extensions and achieves precise timing control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If the processing time is set such that the hole does not penetrate through the oxide film, then the oxide film integrity is maintained, but the etching amount may still exceed the desired amount and the hole may penetrate through the oxide film

Engineering Contradiction:

Improveintegrity of the oxide filmVSAvoidaccuracy of etching amount control

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

Optical emission spectroscopy provides real-time feedback on the etching process, allowing continuous monitoring of hole formation and depth. This enables precise control to stop etching exactly when the desired depth is reached, maintaining oxide film integrity while achieving accurate etching amounts.

Inventive Principle:

Principle #23Feedback

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 enables accurate control of the etching amount, reducing variations and ensuring that the etching process stops at the desired point, thereby preventing over-etching and maintaining the integrity of the oxide film.

Implementation Method 1

measuring, as a luminous intensity of a predetermined wavelength in an emission spectrum of a plasma generated from a processing gas in the chamber

Methodology Applied

Scientific EffectPlasma emission spectrum: Plasma

Implementation Method 2

luminous intensity of the predetermined wavelength in an emission spectrum of a plasma

Methodology Applied

Scientific EffectLuminescence: Luminescence

Data Source

PatentUS10734242B2Substrate processing method and substrate processing apparatus

Publication Date: 2020.08.04 TOKYO ELECTRON LTD

AI summary

In a substrate processing method for performing predetermined processing on a substrate, which has a processing target film, accommodated in a processing chamber, as a luminous intensity of a predetermined wavelength in an emission spectrum of a plasma generated from a processing gas in the chamber, a luminous intensity of the predetermined wavelength which starts to change when actual processing of the processing target film is started is measured. Then, a processing time of the predetermined processing performed after a moment when the measured luminous intensity of the predetermined wavelength is changed, is set.