Speedfam-ipec Corporation

Robert A Eaton

John Andrew Adams

Paul L Holzapfel

Thomas Laursen

Mark A Meloni

Malcolm Grief

Matthew Weldon

Christopher E Barns

Thomas Frederick Bibby, Jr

John C Ptak

Thomas Frederick Allen Bibby, Jr

Charles Hannes

The invention is a method and apparatus for planarizing a wafer. Discrete measurements are taken across the surface of the wafer at a desired spatial density. The measurements may be generated using a flash lamp to reflect a light signal off the surface of the wafer with a spectrometer analyzing the reflected light. A plurality of probes may be used at different locations to shorten the time necessary for taking measurements across the full front surface of the wafer and for allowing a plurality of areas to be sampled substantially simultaneously. A control system receives the measurements and their corresponding locations. The control system is then able to analyze the data looking for areas or bands on the front surface of the wafer that need an increase or decrease in material removal rate. The control system is then able to adjust one or more planarization parameters to improve the process for the current wafer or for future wafers.

Multiprobe detection system for chemical-mechanical planarization tool

A fluid delivery system is provided for delivering a fluid to a polishing surface of a chemical mechanical polishing tool. The system includes a platen, manifold and slurry delivery conduit. The platen has a plurality of conduits for allowing a fluid to pass to the polishing surface. The manifold, through the use of a plurality of channels, controls the fluid distribution to the conduits in the platen. The channel cross-sectional area at substantially every point is greater than, preferably 1.5 to 2 times, the combined cross-sectional area of all the conduits being serviced by the channel. This results in the conduits being the most restrictive feature and a uniform pressure within the manifold. However, the volume of the channels should also be reduced as this reduces the time necessary for a fluid change over. The slurry delivery conduit communicates fluid from a fluid source to the channels in the manifold.

Method and apparatus for distributing fluid to a polishing surface during chemical mechanical polishing

The invention provides calibrated spectrometers in a multi-spectrometer system, where chemical mechanical polishing endpoint detection is an issue. In one aspect of the invention, a spectrometer is calibrated by selecting a filter slide having a predetermined light transmittance or reflectance variation with location (e.g. angular or linear displacement) on the slide. Light is incident on locations on the filter slide, and this incidence light is either transmitted or reflected. Transmitted or reflected light is received by a spectrometer, and the wavelength measured is compared with the known wavelength that corresponds to its location on the slide. The spectrometer is calibrated by normalizing the wavelength readings obtained at various locations on the slide with the known readings dictated by the reference slide. The spectrometers are also calibrated to a standard light source for intensity of light. During polishing of workpieces, each spectrometer monitors surface spectral data, and converts these via its unique normalization factors to normalized values that are then compared with the normalized stored spectral data from the test piece. Once measured data (after normalization) approaches the endpoint set for the test piece within a predetermined degree of difference the endpoint of CMP has been reached and polishing may be manually or automatically terminated.

Method and apparatus for optical endpoint calibration in CMP

An apparatus for optical endpoint detection of a chemical mechanical polishing process, that reduces or eliminates interference effects caused by air bubbles in chemical polishing slurries, and accumulation of polishing debris on components of the optical system. In particular, the invention provides hydrophobic light pipes and windows with polishing surfaces substantially coplanar with surrounding surfaces of polishing pads to thereby eliminate the effect of air bubbles trapped in recesses at the polishing pad surface. Moreover, hydrophobic surfaces have now been found to resist the accumulation of polished debris thereon, resulting in a reduction in loss of optical reflectance over polishing time. Accordingly, the invention provides an optical endpoint system that eliminates or reduces both the oversaturation and loss of reflectance problems of the prior art.

Hydrophobic optical endpoint light pipes for chemical mechanical polishing

An apparatus to generate an endpoint signal to control the polishing of thin films on a semiconductor wafer surface includes a through-hole in a polish pad, a light source, a fiber optic cable, a light sensor, and a computer. A pad assembly includes the polish pad, a pad backer, and a pad backing plate. The pad backer includes a pinhole and a canal that holds the fiber optic cable. The pad backer holds the polish pad so that the through-hole is coincident with the pinhole opening. A wafer chuck holds a semiconductor wafer so that the surface to be polished is against the polish pad. The light source provides light within a predetermined bandwidth. The fiber optic cable propagates the light through the through-hole opening to illuminate the surface as the pad assembly orbits and the chuck rotates. The light sensor receives reflected light from the surface through the fiber optic cable and generates reflected spectral data. The computer receives the reflected spectral data and calculates an endpoint signal. For metal film polishing, the endpoint signal is based upon the intensities of two individual wavelength bands. For dielectric film polishing, the endpoint signal is based upon fitting of the reflected spectrum to an optical reflectance model to determine remaining film thickness. The computer compares the endpoint signal to predetermined criteria and stops the polishing process when the endpoint signal meets the predetermined criteria.

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Scottsdale, AZ, United States of America

Robert A Eaton