Optical Endpoint Detection With High Resolution Spectroscopy

INTRODUCTION

Optical endpoint detection is an important technique in various industries such as semiconductor manufacturing, pharmaceuticals, and environmental monitoring. It enables real-time monitoring and control of processes by determining when a reaction or process has reached a desired state or endpoint. High-resolution spectrometers play an important role in optical end-point detection by providing accurate spectral analysis with good resolution and high sensitivity.

The endpoint is the state where the observed substance is no longer present during processing or vice versa. Therefore, real-time endpoint detection will play a very important role in industrial applications.

METHODOLOGY

When a feature is being etched (applications will be presented in more detail) it is vital to be able to determine at what point the etch process should be halted. If the process runs too long then there will be over-etch and if too short under-etch. The point at which the ideal etch has been reached is known as the end point of the etch process.

If any etching takes place beyond the end point then the device will not be as intended and as such there will be an unknown effect upon the device performance. As features and devices become ever smaller even a small degree of over-etching can destroy the functionality of the device. There are several techniques which have been investigated with regards to end point detection as well as monitor plasma including mass spectrometry, pressure change and bias change. However, we choose ICP-OES for our system.

Our technique will be based on real-time optical emission spectrum and combined with other smart algorithms to be able to determine the endpoint accurately and quickly. Below is a graphic illustration of an endpoint when observed in real time.

And with this technique, the OES input spectrum is a key factor in determining the accuracy of the results. Using a spectrometer with high performance will help the emission spectrum be collected more effectively:

Fine Spectral Resolution: High-resolution spectrometers provide detailed spectral information with narrow spectral bandwidths, enabling the detection of subtle changes in optical properties.

• High Sensitivity: These spectrometers offer high sensitivity, allowing detection of low concentrations or weak signals, which is crucial for monitoring reactions or processes with small changes in optical properties.
• Wide Spectral Range: High-resolution spectrometers cover a broad spectral range, facilitating analysis across different wavelengths and accommodating diverse applications.
• Real-Time Monitoring: With fast acquisition rates and high data processing speeds, high-resolution spectrometers enable real-time monitoring of processes, ensuring rapid detection of endpoints and timely adjustments if necessary.

RECOMMENDED EQUIPMENT

INTINS provides a complete optical system with this application. Includes the most advanced optical components. As for spectrometer, we have a full range of suitable lines for many different applications. Specifically for this application, we recommend a few suitable machine models as follows

The HR4000 Spectrometer is a versatile high-resolution spectrometer. The HR4000 has a 3648-element CCD-array detector from Toshiba that enables optical resolution as precise as 0.02 nm (FWHM). The HR4000 is responsive from 200-1100 nm, but the specific range and resolution depend on your grating and entrance slit choices. This novel combination of optics and electronics is ideal for applications such as characterizing lasers, measuring gas absorbance, and determining atomic emission lines. Interface options include USB.

Ocean HDX spectrometer uses a robust optical bench design, optimized components and precision engineering to maximize optical resolution, increase throughput, reduce stray light and maintain thermal stability for integrated, industrial and research applications. The HDX is responsive from 200-1100 nm.

HDX has a back-thinned CCD array and High Definition Optics design, with X-Platform Electronics to enhance communication capabilities, plus powerful onboard storage and processing functions. Store up to 50.000 spectra and take advantage of onboard averaging to capture more spectral data in less time. Interface options include USB, Gigabit Ethernet, AP Wi-Fi and RS-232.

Besides, we also have many other models with high resolution and reasonable prices suitable for applications. Please get in touch if you need more detailed information.

APPLICATION

Plasma etching in semiconductor manufacturing - this is an advanced application that involves precisely controlled removal of material from a surface to grow patterns on silicon wafers. Plasma etching in semiconductor devices requires extremely precise monitoring of reaction progress  

and is also very susceptible to noise. These factors mean that plasma etching requires extremely precise plasma analysis. Optical emission spectra – typically across spectral regions from near-infrared to near-ultraviolet – provide the speed, stability, and resolution needed for process control. So it can be said that endpoint detection are extremely important.

In addition, in the thin film deposition industry, end-point detection helps monitor film thickness and improve the uniformity of films during production.

In the biomedical field, endpoint detection is capable of detecting interactions of biological molecules and biochemical assays.

CONCLUSION

Endpoint detection will be a great application for current and future industries. Enhance process control, detect quickly and promptly in real time. With the support of a high-resolution spectrometer, it will be extremely convenient to help improve endpoint detection. From there, users can achieve unparalleled sensitivity, specificity, and real-time monitoring in their endpoint detection applications.