Semiconductor Diagnostics, Inc.

Alexander Savtchouk

Jacek J Lagowski

Marshall D Wilson

Lubomir L Jastrzebski

John D'Amico

Nick Kochev

Charles Schraver

A method is described for measuring the capacitance and the equivalent oxide thickness of an ultra thin dielectric layer on a silicon substrate in which the dielectric layer is uniform or patterned. The surface of a dielectric layer is electrically charged by a flux on ions from a corona discharge source until a steady state is reached when the corona flux is balanced by the leakage current across a dielectric. The flux is abruptly terminated and the surface potential of a dielectric is measured versus time. The steady state value of the surface potential is obtained by extrapolation of the potential decay curve to the initial moment of ceasing the corona flux. The thickness of a dielectric layer is determined by using the steady state potential or by using the value of the surface potential after a predetermined time.

Steady state method for measuring the thickness and the capacitance of ultra thin dielectric in the presence of substantial leakage current

A method is described for non-contact measuring the capacitance and the equivalent oxide thickness of ultra thin dielectric layer on a silicon substrate. The surface of a dielectric layer is electrically charged by a flux on ions from a corona discharge source until a steady state is reached when the corona flux is balanced by the leakage current across a dielectric. The flux is abruptly terminated and the surface potential of a dielectric is measured versus time. The steady state value of the surface potential is obtained by extrapolation of the potential decay curve to the initial moment of ceasing the corona flux. The thickness of a dielectric layer is determined by using the steady state potential or by using the value of the surface potential after a predetermined time. The method produces highly accurate results for oxide thickness below 40 &angst; with a demonstrated repeatability of a 0.03 &angst; in a series of 10 measurements. Alternatively, the rate of surface potential decay is calculated at the initial moment providing a measure of the charge dissipation on a dielectric capacitor. The capacitance of a dielectric layer is calculated from this rate.

A method and apparatus for measuring the concentration of different mobile ions in the oxide layer of a semiconductor wafer from the contact potential shift caused by different ions drifting 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 different mobile ions in the oxide to drift. The difference in the contact potential measured before and after heating provides an indication of the different mobile ion concentration in the oxide layer.

Measurement of different mobile ion concentrations in the oxide layer of a semiconductor wafer

SILC characteristics and density of GOI defects of silicon wafers with thin dielectric films (e.g. SiO ) are determined using a non-contact method that does not require any test structures on the wafer. The method includes stressing a dielectric with a corona discharge and measuring the dielectric current-dielectric voltage (I-V) characteristics by monitoring under illumination the corona charge neutralization after stress. An I-V measurement done as function of corona fluence gives SILC characteristics of the wafer. The SILC characteristics are then compared at a constant dielectric field to provide a measure of GOI defect density. The I-V characteristic corresponding to low fluence that does not generate measurable SILC are used to determine a thickness of dielectric film.

Method for measuring stress induced leakage current and gate dielectric integrity using corona discharge

The invention relates to a device for contacting and electrically grounding semiconductor substrate coated with or otherwise having an insulating film positioned thereover. The device includes a chuck having a wafer support surface which holds the wafer and a scriber movably attached to the chuck. The scriber is configured to contact the wafer through an opening in the chuck and to produce a perforation through the insulating film. The device further includes an electrically conductive probe movably attached to the chuck and configured to be moved into an access opening in the chuck to contact the semiconductor substrate through the perforation. Thus, the device increases the accuracy of open circuit type measurements of the wafer surface potential, particularly for Kelvin and Monroe electrode measurements of electrical properties of insulating films on semiconductor substrates.

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Alexander Savtchouk