Semiconductor Diagnostics, Inc.

University of South Florida

Semiconductor Diagostics, Inc.

Piotr Edelman

Jacek J Lagowski

Lubek Jastrzebski

Marshall D Wilson

Andrew M Hoff

Alexandre Savtchouk

Dmitriy Marinskiy

Carlos Almeida

Joseph Nicholas Kochey

Andrzej Kontkiewicz

Nick Kochey

Frank Gossett

A non-contact method is described for acquiring the accurate charge-voltage data on miniature test sites of semiconductor wafer wherein the test sites are smaller than 100 &#x3bc;m times 100 &#x3bc;m. The method includes recognizing the designated test site, properly aligning it, depositing a prescribed dose of ionic charge on the surface of the test site, and precise measuring of the resulting voltage change on the surface of the test site. The method further compromises measuring of the said voltage change in the dark and/or under strong illumination without interference from the laser beam employed in the Kelvin Force probe measurement of the voltage. The method enables acquiring of charge-voltage data without contacting the measured surface of the wafer and without contaminating the wafer. Thus, the measured wafer can be returned to IC fabrication line for further processing.

Non-contact method for acquiring charge-voltage data on miniature test areas of semiconductor product wafers

Techniques for measuring a contact potential difference of a sample at an elevated temperature using a probe designed for room temperature measurement are disclosed. In such measurements, probe damage by excessive heating can be prevented without any probe modifications to include probe cooling. This can be achieved by minimizing the time the probe spends in close proximity to the heated sample. Furthermore, the effect of probe heating by the sample on the probe reading can be corrected by including an additional contact potential difference measurement of a reference plate kept at room temperature in the measurement cycle.

Method and system for elevated temperature measurement with probes designed for room temperature measurement

A method of determining charge associated with traps present in a semiconductor oxide interface is described. The method includes the steps of depositing a dose of charge over a surface of the oxide and measuring a resultant value of surface potential barrier at the portion of the surface. From the measured value of surface charge and deposited charge dose a value of charge associated with the interface trap is determined. The method also includes determining space charge corresponding to the measured surface potential barrier of the portion of the substrate. With the determined space charge and known deposited charge the interface trapped charge is determined by noting that the change in interface trapped charge is related to the negative of the changes in space charge and deposited charge.

Measurement of the interface trap charge in an oxide semiconductor layer

A method and apparatus for measuring the concentration of mobile ions in the oxide layer of a semiconductor wafer from the contact potential shift caused by ion drift across the oxide that includes depositing charge (e.g., using a corona discharge device) on the surface of the oxide and heating the wafer to allow mobile ions in the oxide (especially Na.sup.+) to drift. The difference in the contact potential measured before and after heating provides an indication of the mobile ion concentration in the oxide layer.

Measurement of the mobile ion concentration in the oxide layer of a

Minority carrier diffusion lengths, especially long diffusion lengths that exceed the thickness of the wafer, are determined accurately and conveniently using techniques that limit errors due to lateral carrier diffusion, surface reflectivity, temperature variations, and inherent limitations in standard computation techniques that assume a diffusion length shorter than the wafer thickness. In particular embodiments, a probe is provided that senses the photovoltage in an area spaced from the edge of the illuminated region to provide a measurement substantially free of error from lateral carrier diffusion. The probe may also measure surface reflectivity simultaneously with measurement of photovoltage. Reflectivity correction is particularly beneficial in the analysis of wafers with dielectric coatings.

Determining long minority carrier diffusion lengths

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Tampa, FL, United States of America

Piotr Edelman