GEKA ASSOCIATES, with a proven track record in introducing breakthrough equipment for the microelectronics industry is seeking a partnership with an industrial entity interested in the productization and commercialization of two on-line process control modules based on the commercially proven technologies currently used in off-line process monitoring requiring monitor wafers:

  • A patented RF-based, non-contact electrical measurement system referred to as Defect Specific Lifetime Analyzer (DSLA) for on-line monitoring of semiconductor surface and bulk defects in microelectronic and wide bandgap semiconductor device manufacturing.

  • A proprietary photo-thermal surface cleaning on-line module for elipsometry and other applications identified by device manufacturers including a pre-clean treatment for gate oxidation, silicon epitaxy, and wafer bonding processes.

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Existing systems (Surface Charge Analyzer and Surface Charge Profiler) can not be used for in-line monitoring of product wafers. They require monitor wafers that can not be returned into the production line. In spite of this limitation, in case of batch wafer processing such as thermal oxidation, low pressure chemical vapor deposition (LPCVD) of silicon nitride, resist strips and wafer cleaning processes, monitor wafers can be effectively used for monitoring of the processing flow. However with increasing wafer diameter and tightening requirements to achieve finer features a need for high quality deposition and etch processes is driving towards single wafer processing that eliminates usage of monitor wafers.

Defect Specific Lifetime Analyzer [DSLA©]

E. Kamieniecki, J. App. Physics 112, 063715 (2012); Patents: US 7,898,280,B2; US 8,896,338,B2

This deficiency of existing metrologies, and specifically the Surface Charge Analyzer which requires the use of monitor wafers is addressed by non-contact Defect Specific Lifetime Analyzer (DSLA) which is based on the proprietary analysis of the time dependent density of optically generated charge carriers, DSLA simultaneously differentiates properties of the surface and bulk of semiconductors focusing on, depending on the probe configuration, on the surface or bulk regions. Unlike Surface Charge Analyzer (SCA), Defect Specific Lifetime Analyzer (DSLA) operates at wide probe-semiconductor gap making it particularly useful for on-line process monitoring of product wafers in microelectronic and wide bandgap semiconductor device manufacturing. The probe-semiconductor gap can be tailored to process requirements and configuration of the probe can be adjusted enhancing monitoring of the process parameters critical for device performance e.g. by separating sub-surface contacts regions and bulk characteristics of the devices.

Since DSLA measurements do not involve current flow and the collection of charges at the electrodes but are solely based on the absorption of the RF radiation, DSLA can be used for the characterization of monocrystalline, polycrystalline, and amorphous materials.

The capabilities of the DSLA for on-line monitoring of the photo-current radiation detectors fabrication are detailed on the Radiation Detectors page. In this application DSLA not only identifies point and extended defects that directly affect performance of the detectors but also shows that electrode formation is a critical factor affecting reproducibility of the fabrication process. In the defect enhanced mode of operation the DSLA signal increases with density of defects which may be particularly important in evaluation of compound semiconductor wafers.

Dependence of the electrostatic surface potential barrier controlled recombination time constants at Cd and Te faces on the energy resolution of detectors fabricated with a high quality n-type high resistivity CZT.


Miniaturization of semiconductor devices requires control of oxide thickness at sub-atomic levels and substantial reduction of the surface contamination by removing the hydrocarbon layer along with the species deposited on it. GEKA developed "Rapid Optical Surface Treatment" (ROST) technology offers fast, non-contact, and non-invasive surface cleaning which is based on the photo-thermal phenomena. The first application of ROST technology, featured in Solid State Technology (Sep, 1999), was for thin-film measurements. It was demonstrated that ROST lifts off the absorbed dipol layer from the surface of a wafer, removing with it any deposited species in much shorter time and more effectively than standard wet cleaning processes. The process is done at temperature below 300 degree C in <1min. [2,3]


On-Line Photo-thermal cleaning (ROST) of product wafers

GEKA proprietary new non-contact on-line Photo-Thermal Cleaning Modules are tailored to customer specified applications for thin film measurements (ellipsometry) and final pre-clean treatment in gate oxidation, silicon epitaxy, and wafer bonding applications. The modules design will allow their integration into existing metrology and processing systems.

In-line modules are not intended to replace chemical cleaning e.g., after long storage of the wafers but supplement them with final clean before next processing step.

A. Danel, C.L. Tsai, K. Shanmugasundaram, F. Tardif, E. Kamieniecki and J. Ruzyllo, Cleaning of Si Surfaces by Lamp Illumination, Presented at UCPSS, Sep. 16, 18, 2002, Oostende, Belgium. [ROST-3]