Novellus Systems Incorporated

Baker Hughes Oilfield Operations LLC

Zhao Li

David Wingto Cheung

Haoquan Fang

Ilia Kalinovski

Kirk J Ostrowski

Jack Kuo

Anirban Guha

Paul Wysocki

Dan Provenzano

Guhua Yao

An optical system performs a method for measuring an acoustic signal in a wellbore. The optical system includes a light source, an optical fiber and a detector. The light source generates a light pulse. The optical fiber has a first end for receiving the light pulse from the light source and a plurality of enhancement scatterers spaced along a length of the optical fiber for reflecting the light pulse. A longitudinal density of the enhancement scatterers increases with a distance from the first end to increase a signal enhancement generated by the enhancement scatterers distal from the first end. The detector is at the first end of the optical fiber and measures a reflection of the light pulse at the enhancement scatterers to determine the acoustic signal.

Enhanced backscatter fiber with tapering enhancement

Improved methods for stripping photoresist and removing ion implant related residues from a work piece surface are provided. According to various embodiments, plasma is generated using elemental hydrogen, a fluorine-containing gas and a protectant gas. The plasma-activated gases reacts with the high-dose implant resist, removing both the crust and bulk resist layers, while simultaneously protecting exposed portions of the work piece surface. The work piece surface is substantially residue free with low silicon loss.

Ultra low silicon loss high dose implant strip

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Blacksburg, VA, United States of America

Zhao Li