CryoSAS All-In-One Cryogenic Silicon Analysis System

The Cryogenic Silicon Analysis System (CryoSAS) from Bruker Optics is an all-in-one system for the low temperature (<15K) impurity analysis of silicon. The CryoSAS is built to handle operation in the industrial environment.

The CryoSAS combines Bruker's high performance FTIR spectrometers with an integrated, closed-cycle cryo-cooling method that does not need any liquid helium. All CryoSAS components are sophisticated, and utilize well-established technologies to accomplish a difficult analysis in the challenging silicon production environment.

The CryoSAS can be operated at a high level of automation, which includes accurate reporting of the analysis results.

Features

High sensitivity: The CryoSAS tests shallow impurities (e.g. boron and phosphorous) down to the low ppta level in compliance with the ASTM/SEMI MF1630 standard. Additionally, it simultaneously analyzes oxygen and carbon down to the low ppba level in compliance with the ASTM/SEMI MF1391 standard.

CryoSAS measurement results for carbon (see above) as well as for Boron and Phosphorus (see below) at low temperatures (~12 K).

Closed-cycle cryogenic refrigeration system: Expensive liquid cryogens are not needed. A very reliable closed cycle cryo-cooling system for sample chamber and detector cooling. The closed cycle system can save € 50,000 in operation costs annually and even more compared to a liquid helium cooled refrigeration system.

CryoSAS low temperature sample compartment with automated 9 position sample holder.

CryoSAS main software screen displaying the currently loaded samples and the chosen analysis methods.

Stainless steel sample chamber design: Easy sample access. Proven sample chamber design with stationary optics and automated sample head. The sample chamber’s large inner diameter allows for easy sample holder access.

Dry fore pump and turbo pump: Simple and clean vacuum system operation Quick and reliable evacuation via turbodrag pump and dry fore pump.

Robust, precision stepper motor stage with nine position sample holder: The sturdy translation stage interfaced to the sample holder enables multiple sample analysis. The high torque motor and solid translation mechanism provide precise sample indexing and prolonged reliable functionality. Samples can be easily installed and removed and the sample holder can be quite easily attached in the sample chamber. The gold-coated OFHC copper design of the sample holder ensures even temperatures.

Ease of use

The CryoSAS is optimized handle operation in the industrial environment. A PLC controls all vacuum and refrigeration devices. Cooling down and starting the measurement is a simple push button operation. The user does not have to be a vacuum expert or a spectroscopy expert.

The dedicated CryoSAS software is designed to meet the needs of industrial quality control. It is simple to use and can be operated via touch screen. The user just has to choose the preferred analysis technique, enter the sample data and click the start button. The CryoSAS will then automatically cool down the samples, begin the infrared measurement, evaluate the results, and prepare an analysis report.

Specifications

Spectral range: 1500 – 280 cm^-1 optimized for the detection of

Group III and V shallow impurities in single crystal Si according to ASTM/SEMI MF1630. For wedged samples with a thickness of approximately 3 mm, the following detection limits can be achieved:

10 ppta phosphorus

30 ppta boron

Substitutional carbon according to ASTM/SEMI MF1391. This technique requires a carbon free FZ reference sample with thickness and surface properties comparable to the sample specimen. For a wedged sample with a thickness of approximately 3 mm, carbon concentrations as low as 20 ppba can be detected.

Typical CryoSAS analysis report including all relevant information and results.