Adaptive Etch End-Point Detection for Deep Multilayer Films
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Solution Overview
Problem
Existing methods for detecting the end point of etching processing in multilayer films are inaccurate, especially at increased depths, leading to difficulties in controlling the etching process and affecting the surface roughness and aperture ratio of semiconductor devices.
Innovation Solution
An end point detection device that measures a physical quantity using absorption spectroscopy and adjusts the detection algorithm based on previous etching processing of similar films in the same multilayer structure, allowing for precise detection of the end point and transition to the next film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If optical emission spectroscopy is used to detect the end point of etching processing, then the detection method is simple and widely applicable, but the measurement precision deteriorates in non-plasma processes, at low aperture ratios, and at increased etching depths
Solution Approach 1:
The patent changes the measurement parameter from optical emission intensity to absorption spectroscopy signals. By measuring the absorption of light by species in the plasma or process environment, the system achieves accurate end point detection in non-plasma processes and at low aperture ratios where emission spectroscopy fails. This parameter change resolves the contradiction by maintaining measurement precision across diverse etching conditions while preserving the simplicity of optical-based detection methods.
2Productivity
If the etching depth increases in multilayer film processing, then more films are removed and the process progresses, but the aperture ratio decreases and end point detection becomes more difficult
Solution Approach 1:
The patent implements a feedback mechanism where absorption spectroscopy measurements are continuously monitored during etching processing. The system detects changes in absorption signals that indicate approaching end points, even at increased depths and reduced aperture ratios. This real-time feedback allows the etching process to progress through multiple layers while maintaining accurate end point detection capability, resolving the contradiction between productivity and measurement precision.
3Ease of operation
If a fixed detection algorithm is used for end point detection, then the system is simple to operate, but the detection accuracy deteriorates when processing different films with varying characteristics
Solution Approach 1:
The patent introduces a dynamic detection algorithm that automatically adapts to different film types and etching conditions. The system adjusts detection parameters and thresholds based on real-time measurement data, enabling accurate end point detection across diverse multilayer film structures. This dynamic adaptation maintains system simplicity for operators while significantly improving measurement precision for varying film characteristics, resolving the contradiction between ease of operation and detection accuracy.
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
Enables high-accuracy etching processing of multilayer films by accurately determining the end point, improving the etching process control and reducing surface roughness and increasing the yield ratio of semiconductor devices.
Implementation Method 1
a measurement unit that measures a physical quantity that changes with the etching processing
Data Source
AI summary
An end point detection device that detects an end point in etching processing of a multilayer film, includes a measurement unit that measures a physical quantity that changes with the etching processing, an end point detection unit that detects an end point in a target film for which the end point is to be detected using a predetermined detection algorithm based on a measurement value obtained by the measurement unit, and an algorithm change unit that changes the detection algorithm in the film that is being subjected to the etching processing based on the measurement value obtained by the measurement unit when another film of a same type as the target film was being subjected to the etching processing in a same multilayer film as the target film currently being etching processed.