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-ULS3648-USB2 and AvaSpec-ULS2048L-EVO spectrometer. The AvaSpec-ULS3648-USB2 is configurable over the range from 190-1100 nm with resolution as high as 0.05 nm (FWHM) and communication options including USB2 and RS-232. The AvaSpec-ULS2048L-EVO offers the same spectral range (200-1100 nm) and resolution as high as 0.07 nm but the advantage of onboard Gigabit Ethernet or high-speed USB3 communication. The optical interface for both spectrometers are fiber optic cables or probes which are available in a variety of configurations (see below). 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 these calibration services are available from Avantes.
Thin Film Measurements
During coating processes and after completion, thin film thickness measurement 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 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-ULS2048L-USB2 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-NIR256-1.7, AvaSpec-NIR256-1.7-TEC and AvaSpec-NIR512-1.7TEC are the most commonly deployed instruments for near infrared thin film metrology. Avantes 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.
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 involve the measurement of reflection in high speed in the ultra-violet, visible or near infrared from 200-1100 nm. Avantes uses a variety of instruments for this application including the AvaSpec-ULS2048XL-USB2 high sensitivity back-thinned spectrometer or the AvaSpec-ULS2048-USB2 spectrometer. As resolution is not typically critical in this application, focus is placed on throughput in lieu of resolution to optimize on sampling speeds. Avantes new AvaSpec-ULS2048L-EVO offers the advantage of ultra-fast USB3 communication to facilitate the maximum sample acquisition speeds.
All Avantes instruments are available as laboratory instruments in single channel housing or multi-channel "rackmount" housings as well as OEM modules (see below)
Fibers and Probes
In many cases, fiber optic sampling is useful to photonics applications. Avantes offers a complete line of fiber optic and sampling accessories to facilitate your measurements. Requests for customization are welcome.