International Business Machines Corporation

Infineon Technologies North America Corp.

George G Gifford

Jeffrey P Gambino

Gary S Selwyn

Jyothi Singh

Edward Kobeda

Brock E Osborn

Reid S Bennett

Kurt L Haller

Nickolas Joseph Mazzeo

Albert R Ellingboe

John S McKillop

Viraj Yashawant Sardesai

Anthony Gene Domenicucci

Christopher Carr Parks

Atul Champaklal Ajmera

Christine Dehm

James Anthony O'Neill

Jin J Wu

Stephen K Loh

Yeong-Jyh T Lii

A 'porous barrier' is formed without formation of a discrete barrier layer by enriching grain boundaries of a body of polysilicon with nitrogen to inhibit thermal mobility of silicon species therealong. In a polycide gate/interconnect structure, the reduced mobility of silicon suppresses agglomeration of silicon in a metal silicide layer formed thereon. Since silicon agglomeration is a precursor of a polycide inversion phenomenon, polycide inversion which can pierce an underlying oxide and cause device failure is effectively avoided. The increased thermal stability of polycide structures and other structures including a body of polysilicon thus increases the heat budget that can be withstood by the structure and increases the manufacturing process window imposed by the presence of polysilicon which can be exploited in other processes such as annealing to develop a low resistance phase of refractory metal silicide included in the polycide structure, drive-in annealing for formation of source/drain regions of field effect transistors and the like.

Titanium polycide stabilization with a porous barrier

The present invention provides a method for fabricating tungsten local interconnections in high density CMOS circuits, and also provides high density CMOS circuits having local interconnections formed of tungsten. Pursuant to the method, an etch stop layer of chromium is initially deposited on the circuit elements of the CMOS silicon substrate. Next, a conductive layer of tungsten is non-selectively deposited on the chromium layer. A photoresist mask is then lithographically patterned over the tungsten layer. The tungsten layer is then etched down to, and stopping at, the chromium layer, after which the photoresist mask is stripped. The stripping preferably uses a low temperature plasma etch in O.sub.2 at a temperature of less than 100.degree. C. Finally, a directional O.sub.2 reactive ion etch is used to remove the chromium layer selectively to the silicon substrate. Borderless contacts are formed with the aid of the chromium etch stop layer beneath the tungsten local interconnection layer. The method of integration of this approach results in anisotropic metal lines patterned over topography using a standard photoresist mask. This approach also allows partial overlap of contacts to reduce device dimensions, and thereby results in improved density and performance.

Method for fabricating Tungsten local interconnections in high density

Analysis of plasma data indicative of gaseous species therein, such as Optical Emission Spectroscopy (OES) data, is aided through the interactive use of a computer. OES data may be calibrated by the computer with minimal input from the user regarding a gas the user knows or suspects is present. The computer then assumes the presence of that gas and assigns relative intensity peaks to known wavelengths for that gas, allowing calibration to take place. Selective identification of particular gases from the data is also possible. Used in conjunction with selective identification, a learning function allows the system to improve the accuracy of future gaseous species identification. Certain characteristics of a particular gas over time, such as intensity at a particular wavelength or at all wavelengths, may also be automatically plotted.

Method and system for analyzing plasma data

Contamination levels in plasma processes are reduced during plasma processing, by prevention of formation of particles, by preventing entry of particles externally introduced or by removing particles spontaneously formed from chemical and/or mechanical sources. Some techniques for prevention of formation of particles include interruption of the plasma by pulsing the source of plasma energy periodically, or application of energy to provide mechanical agitation such as mechanical shockwaves, acoustic stress, ultrasonic stress, vibrational stress, thermal stress, and pressure stress. Following a period of applied stress, a tool is pumped out (if a plasma is used, the glow is first discontinued), vented, opened and flaked or particulate material is cleaned from the lower electrode and other surfaces. A burst of filtered air or nitrogen, or a vacuum cleaner is used for removal of deposition debris while the vented tool is open. Following this procedure, the tool is then be used for product runs. Alternatively, improvement of semiconductor process yields can be achieved by addition of reagents to getter chemical precursors of contamination particulates and by filtration of particulates from feedgas before plasma processing. The efficiency and endpoint for the applied stress are determined, by laser light scattering, using a pulsed or continuous laser source, e.g. a HeNe laser.

Methods and apparatus for contamination control in plasma processing

A method of fabricating a semiconductor structure includes the steps of providing a semiconductor substrate having a material disposed thereon, masking the material with a mask having an appropriate pattern for forming a semiconductor structure, etching unmasked portions of the material so as to form the semiconductor structure, wherein the etching produces a film which attaches onto the semiconductor structure and/or on the semiconductor substrate, and removing the film from the semiconductor structure according to the steps of producing a cryogenic jet stream having cryogenic particles therein, and directing the cryogenic jet stream at the film such that the crogenic jet stream impinges on and causes the film to decrease in temperature so that a high temperature gradient develops between the film and the semiconductor structure, the film detaching from the semiconductor structure and fracturing due to contraction caused by the decrease in temperature and high temperature gradient.

Process for fabricating a semiconductor structure having sidewalls

Contamination levels in plasma processes are reduced during plasma processing, by prevention of formation of particles, by preventing entry of particles externally introduced or by removing particles spontaneously formed from chemical and/or mechanical sources. Some techniques for prevention of formation of particles include interruption of the plasma by pulsing the source of plasma energy periodically, or application of energy to provide mechanical agitation such as mechanical shockwaves, acoustic stress, ultrasonic stress, vibrational stress, thermal stress, and pressure stress. Following a period of applied stress, a tool is pumped out (if a plasma is used, the glow is first discontinued), vented, opened and flaked or particulate material is cleaned from the lower electrode and other surfaces. A burst of filtered air or nitrogen, or a vacuum cleaner is used for removal of deposition debris while the vented tool is open.

Automated, closed loop method and system for monitor and control of semiconductor fabrication processing are described. Optical emissions spectrometer (OES) data readings from a fabrication plasma chamber are statistically analyzed and a novel pattern model (based on Markov random fields) is used in combination with a selective stochastic relaxation technique to identify gaseous species within the chamber from the OES readings. Wavelength and intensity information is also employed to accurately estimate relative concentration levels of identified gases within the chamber. The unique statistical analysis approach described allows real-time monitor and control of physical processing within the fabrication chamber. Several practical algorithms are set forth, including techniques for OES peak identification, peak sharpening, gas identification, and physical processing control.

Method and system employing optical emission spectroscopy for monitoring

Method for fabricating tungsten local interconnections in high density

An infrared television camera (20) monitors the etching of a substrate (26) in-situ in an etch chamber (24). Temporal and spatial resolution of IR emissions is obtained by monitoring the top surface of the substrate (26) in two-dimensions throughout the course of the etching process. Anomalies in temperature detected on the top surface of the substrate (26) can indicate defects in the substrate (26) itself or in the operation of the etching apparatus. Process feedback control is achieved by adjusting various parameters of the etching apparatus (i.e., gas-pressure, flow pattern, magnetic field, coolant flow to electrode, or the like) to compensate for etching anomalies. Etch uniformity and etch endpoint monitoring is achieved by monitoring the IR emissions resulting from exothermic reaction of the film being etched. IR emissions decline at the end of an exothermic etch reaction. Particulate matter which might otherwise harm the substrate (26) can be identified in the gas-phase with a second IR television camera (34) which images the region above the substrate (26). Particulate matter appears as localized 'hot spots' within the gas plasma, and the identification of particulate matter allows corrective measures to be taken.

Growing community of inventors

Poughkeepsie, NY, United States of America

George G Gifford