Near Real-Time Analysis

The semiconductor industry can realize significant benefits from spectroscopic measurements during various stages of their processes.  Fiber-optic based spectrometers offer a great value to the industry due to their ability to facilitate in situ measurements within processing environments and facilitate near real-time analysis.

Avantes works with semiconductor applications such as end-point detection for plasma ion etching, ion beam etching, photoresist stripping, and chemical/mechanical polishing. Instrument configurations have also been deployed in environments for thin film metrology (inline and offline) and plasma diagnostics.

Plasma Diagnostics & End-Point Detection 

Measuring a complex yet dynamic matrix like plasma requires high-speed acquisition combined with high resolution.  Real-time, high-resolution spectroscopic sampling of plasma can be realized using the AvaSpec-ULS4096CL-EVO and AvaSpec-ULS2048CL-EVO spectrometers. The AvaSpec-ULS4096CL-EVO is configurable over the range from 190-1100 nm with resolution as high as 0.05 nm (FWHM) and communication options including USB3, gigabit ethernet, and RS-232.  The AvaSpec-ULS2048CL-EVO offers the same spectral range (200-1100 nm) and resolution as high as 0.07 nm.

The optical interface for both spectrometers are fiber-optic cables or probes which are available in a variety of configurations.  Either of these spectrometers can be integrated as an OEM module or within a laboratory or rackmount housing.  The rackmount housing option facilitates arrayed instruments for environments where high resolution is needed over a large spectral range or multiple reductant measurements are desired within a process.  Frequently, instruments configured for plasma diagnostics and endpoint detection are intensity calibrated using a NIST traceable calibration source and the calibration services Avantes has available.

Thin Film Measurements

During coating processes and after completion, thin film thickness measurements may be required to ensure processes are under control.  It may be desirable to stop a coating process based on a measured value obtained during the deposition. The measurement of thin films in the semiconductor industry is achieved through a  reflection or transmission measurement in which known optical constants of the substrate and coating materials are used to calculate theoretical thickness which is then compared to measured thickness through an optical probe or transmission stage. 

Avantes has deployed the AvaSpec-ULS2048CL-EVO spectrometer into multiple thin film applications. Reflection and transmission-based thin film measurements are typically done in the 200-1100 nm range and are suited to coatings ranging from 10 nm-50 µm. For thicker film measurements, Avantes’ NIRline instruments can be utilized. The AvaSpec-NIR256/512-1.7-EVO and its cooled version: the AvaSpec-NIR256/512-1.7-HSC-EVO are the most commonly deployed instruments for near-infrared thin film metrology. 

Avantes also offers a complete line of light sources to support the illumination side of the thin film measurement.  The AvaLight-DHc and AvaLight-DH-S deuterium halogen light sources and AvaLight-HAL-S-Mini tungsten halogen sources are available as independent sources or for integration into rackmount configuration next to the spectrometer(s) used for measurement.

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Wafer Inspection

The inspection or probing of wafers is ideally suited to fiber-optic spectroscopy as it facilitates measurements of very small areas (as low as 50-100 micron spot sizes).  Typical wafer probing applications in the semiconductor industry involve the measurement of reflection at high speed in the ultra-violet, visible or near infrared from 200-1100 nm. 

Silicon Wafer

Avantes uses a variety of instruments for this application, including the AvaSpec-ULS2048XL-EVO high sensitivity back-thinned spectrometer or the AvaSpec-ULS2048CL-EVO high resolution spectrometer. As the resolution is not typically critical in this application, focus is placed on throughput in lieu of resolution to optimize on sampling speeds. These spectrometers offer the advantage of ultra-fast USB3 communication to facilitate the maximum sample acquisition speeds.

Why Avantes for your semiconductor application?

  • High resolution (0.1 nm FWHM or better) spectral data collection for optical emission spectroscopy applications such as endpoint detection
  • High-speed measurement capability (ms time scale) for wafer probing throughput
  • Ability to support thin film metrology applications covering 360-1100 and 200-1100 nm
  • Wide selection of back-thinned CCD array instruments for optimal SWIR measurements (800-1100 nm) of coatings

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Related Products

These are some of the products mentioned in the application examples above. To find the perfect setup for your specific application, contact one of our sales engineers for advice.

Application Examples

Below are some detailed application notes on various uses of spectroscopy in the lighting industry.