Advanced Micro Devices Corporation

Varian Semiconductor Equipment Associates, Inc.

Zhiyong Zhao

David Hendrix

Christian Krueger

George Gammel

Daniel Alvarado

Clive Martin Jones

Jack J Bisson

Tom Tse

Craig Walker

Disclosed herein are various methods of determining characteristics of doped regions on device wafers, and a system for accomplishing same. In one illustrative embodiment, the method includes providing a device substrate comprising a plurality of masked areas, a plurality of unmasked areas, and at least one doped region formed in the substrate, determining a ratio between the unmasked areas and the masked areas for the device substrate, illuminating an area of the device substrate comprising the masked areas, the unmasked areas, and at least one doped region, and measuring an induced surface photovoltage of the device substrate while accounting for the ratio of the unmasked areas and the masked areas of the device substrate. In another illustrative embodiment, the method includes providing an SOI substrate comprised of an active layer, the active layer having a thickness, illuminating an area of the substrate using a light source having a wavelength that is sufficiently long such that an excited region created in the active layer due to the illumination does not extend beyond the thickness of the active layer, and measuring an induced surface photovoltage resulting from the illumination.

Methods of determining characteristics of doped regions on device wafers, and system for accomplishing same

A method for electrostatic discharge depolarization is implemented. The buildup of charge on tool structures in fabrication tools for semiconductor processing may be expected to be of concern whenever high voltage is employed near the structure in a tool. The process herein includes selectively exposing the structure to a plasma for a selected time interval. The duration of the exposure time interval is sufficient to reduce the polarization of the structure whereby the forces due to the polarization do not interfere with the transport or movement of a wafer being processed.

Electrostatic discharge depolarization using high density plasma

A method is presented for compensating for the effects of charge neutralization in calculating the 'true' ion dose, i.e., the dose assuming no changes of charge state of ions during an implantation process. An ion beam is generated under normal operating conditions, e.g., stable vacuum exists, and no target is being implanted. At least one additional detector would be positioned in the target chamber, and a dose measurement conducted simultaneously with a measurement of the beam current with the Faraday, which is located outside of the charge neutralization region, to establish a reference ratio. A wafer is then placed at the target location, and simultaneous measurements made with the additional detector and Faraday, as before, to determine the ratio between the beam current and the detector during wafer implantation. Any drift from the reference ratio indicates the dose error due to charge neutralization from wafer outgassing during implantation. Software for controlling various parameters could be configured to use the ratio drift data to change the dose counter to compensate for the dose error due to charge neutralization.

Method and system for dose control during an ion implantation process

A Faraday system for measuring ion beam current in an ion implanter or other ion beam treatment system includes a Faraday cup body defining a chamber which has an entrance aperture for receiving an ion beam, a suppression electrode positioned in proximity to the entrance aperture to produce electric fields for inhibiting escape of electrons from the chamber, and a magnet assembly positioned to produce magnetic fields for inhibiting escape of electrons from the chamber. The chamber may have a relatively small ratio of chamber depth to entrance aperture width.

Faraday system for ion implanters

Various methods of determining ion implant dosage are disclosed. In one aspect, a method of processing a semiconductor workpiece that has a device region and an inactive region is provided. A first mask is formed on a first portion of the inactive region. A first implant of ions is performed on the device region and the first mask. A secondary ion mass spectrometry analysis of the first portion of the first mask is performed to determine a composition thereof relative to a standard composition. A dose for the first implant is determined based upon the secondary ion mass spectrometry analysis of the first portion of the first mask. The first implant dose is compared with a prescribed dose for the first implant to determine if a second implant is necessary to achieve the prescribed dose, and if so, an appropriate make-up dose for the second implant.

Analysis of ion implant dosage

An electrostatic lens with glassy graphite electrodes for use in an ion implanter is disclosed. The graphite electrodes have been manufactured to be substantially smooth (glassy) such that irregularities on the surface grain of the graphite, for example peaks or apexes, are no longer present. In an embodiment, employing polished graphite electrostatic lens electrodes does not require the time-consuming conditioning operations under vacuum that are typically needed with conventional graphite electrodes, and thus offers the advantage of increased uptime for an ion implantation system. In addition, because surface irregularities are not present to serve as discharge points for electrostatic buildup, the use of glassy graphite electrodes as disclosed offers the advantage of electrostatic discharge reduction. Reduction of electrostatic discharge results in decreased particulate contamination from discharge events, as well as lessening of the probability of irreparable physical damage to implantation target material.

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Austin, TX, United States of America

Zhiyong Zhao