International Business Machines Corporation

Other

Ecophysics Ag

Leping Li

Steven G Barbee

Tony F Heinz

Cong Wei

James Albert Gilhooly

Clifford Owen Morgan, Iii

Eugene Henry Ratzlaff

Arnold Halperin

Yiping Hsiao

Xinhui Wang

Justin W Wong

Chienfan Yu

Victor J Silvestri

William Joseph Surovic

Walter Imfeld

Werner Moser

Madhav Datta

Ravindra V Shenoy

Scott R Cline

Justin Wai-chow Wong

Bruno Greuter

Heinz Stuenzi

Robert B Lipori

Yingru Gu

Matthias Kutter

Joseph Knee

Hung-Chin Guthrie

Richard John Lebel

Eric James Lee

Rock Nadeau

Anne Elizabeth McGuire

Gary R Doyle

Francisco Agustin Martin

Ulrich Hofer

Michael J Balconi-Lamica

Francis Walter Kazak

Kevin L Holland

Richard Mars Ruggiero

Adrian Siegrist

William Joseph Surovie

Heinz Stunzi

Improved endpoint detection is obtained for wet etch and/or other chemical processes involving in situ measurement of bath impedance. The endpoint detection uses a measurement apparatus having a measurement circuit with a capacitor designed to alter the phase angle of the circuit. The capacitor is preferably a variable capacitor which is used to set the initial phase angle of the measurement circuit to about zero. The methods using the improved detection enable etch to be more precisely controlled even under conditions where noise would otherwise adversely impact determination of the endpoint.

Enhanced endpoint detection for wet etch process control

An apparatus for measuring ammonia gas concentration in an ongoing chemical mechanical polishing (CMP) cycle utilizing an acidic CMP slurry, having the following components:

Apparatus for detecting CMP endpoint in acidic slurries

An apparatus for measuring ammonia gas concentration in an ongoing mechanical polishing (CMP) cycle utilizing an acidic CMP slurry, having the following components:

Method for detecting CMP endpoint in acidic slurries

A chemical-mechanical polishing (CMP) system and method includes pumping polishing slurry from a CMP apparatus through a sampling tube to an endpoint detection apparatus during a polishing operation, and flushing the sampling tube while a polishing operation is not in progress. The flushing of the sampling tube is commenced in accordance with a control signal from the endpoint detection apparatus terminating the polishing operation; the flushing is terminated in accordance with a starting signal to the CMP apparatus. The pump, which pumps a sample of slurry into the endpoint detection apparatus, continuously pumps slurry and/or water. Clogging of the slurry sampling tube is thus eliminated, thereby ensuring robust operation of the CMP apparatus. Contamination of the sampling tube is also avoided, so that the system may reliably provide sensitive endpoint detection and process control, even when a film of low pattern density is polished.

Endpoint detection in chemical-mechanical polishing of patterned wafers having a low pattern density

A method is described for noise reduction in a CMP endpoint detection system employing torque measurement. The torque signals are acquired using an adjustable sampling rate and sample size, and averaged using a moving array of adjustable size. By introducing these three adjustable quantities in the torque-based endpoint control algorithm and properly setting their values in the endpoint detection recipe, periodic noise associated with carrier rotation and carrier oscillation can be effectively removed. This in turn permits reliable, closed-loop control of the CMP process.

Technique for noise reduction in a torque-based chemical-mechanical polishing endpoint detection system

An apparatus is described for detecting the presence of a gaseous chemical produced during a chemical-mechanical polishing operation. The apparatus includes a catalytic converter, a reaction chamber and a light sensor. The catalytic converter, heated to about 800&deg; C. converts the chemical to a different chemical product. The reaction chamber produces an excited species; the pressure in the reaction chamber is maintained sufficiently low to substantially avoid collisional deactivation of the excited species, so as to permit real-time detection of the chemical. A light signal from the excited species is input to the light sensor. An output from the light sensor corresponds to the real-time detection of the chemical, thereby permitting real-time control of the chemical-mechanical polishing operation.

Chemiluminescence detection apparatus

Detection of the endpoint for removal of a target film overlying a stopping film by removing the target film with a process that selectively generates a chemical reaction product (for example ammonia when polishing a wafer with a nitride film in a slurry containing KOH) with one of the stopping film and the target film, converting the chemical reaction product to a separate product, producing excited molecules from the separate product, and monitoring the level of light emitted from the excited molecules as the target film is removed.

Indirect endpoint detection by chemical reaction and chemiluminescence

Detection of the endpoint for removal of a target film overlying a stopping film by removing the target film with a process that selectively generates a chemical reaction product (for example, ammonia when polishing a wafer with a nitride film in a slurry containing KOH) with either the target or stopping film, and monitoring the level of chemical reaction product as the target film is removed. The reaction product is extracted as a gas from the slurry and monitored using a threshold photoionization mass spectrometer.

Endpoint detection by chemical reaction

A method is described for fabricating a cloisonn&eacute; structure, in which a top surface of a metal oxide layer is made coplanar with a top surface of a metallic structure formed on a substrate. A nitride layer is deposited on at least the top surface of the metallic structure, and the metal oxide layer is deposited over the metallic structure and the nitride layer. The metal oxide layer is then polished by a chemical-mechanical polishing (CMP) process using a slurry, to expose the nitride layer on the top surface of the metallic structure. Polishing of the nitride layer causes ammonia to be generated in the slurry. The ammonia is extracted as a gas from the slurry, and a signal is generated in accordance with the ammonia concentration. The CMP process is terminated in accordance with a change in the signal. In a preferred embodiment, the metal oxide is aluminum oxide, the nitride is aluminum nitride, and the nitride layer is deposited as a conformal layer on the substrate and the metallic structure.

Endpoint detection in chemical-mechanical polishing of cloisonne structures

Determination of an endpoint for removing a film from a wafer, by determining a first reference point removal time indicating when a breakthrough of the film has occurred, determining a second reference point removal time indicating when the film has been polished almost to completion, determining an additional removal time indicating an overpolishing interval, and adding the second reference point removal time with the additional removal time to get a total removal time to the endpoint.

Chemical mechanical polishing endpoint process control

In a chemical mechanical planarization assembly directed for the removal of oxide layers, which stop on films containing silicon nitride, a conventional polishing table is provided with a gas extraction unit which transmits a gas sample to an infrared spectrometer. The presence of ammonia in the slurry, which is generated when a stop layer containing silicon nitride is abraded under high pH conditions, can be detected using infrared spectroscopy and accordingly provides for an in situ endpoint detection method.

Optimization of CMP process by detecting of oxide/nitride interface using IR system

A method is provided to optimize the chemical mechanical planarization process of wafers having a target removal layer and a stop layer. A slurry is added to a polishing table which includes a polishing pad and a platen adapted for rotation; a portion of the slurry is allowed to engage an interface between the polishing pad and the wafer. A gaseous sample is continuously extracted from the slurry; the gaseous sample includes a reactant product created when the polishing pad engages the stop layer. The gaseous sample is introduced into a reactant product detector. A first time is determined, corresponding to an initial detection of the reactant product in the slurry, thereby creating a first reference point. A second time is determined, corresponding to the detection of a maximum volume of the reactant in said slurry, thereby creating a second reference point. The first and second reference points are then processed to obtain a signal, wherein the signal reflects the uniformity of removal of the layer containing the reactant product.

Optimization of chemical mechanical process by detection of oxide/nitride interface using CLD system

A method and apparatus are described for detecting an endpoint of a film removal process in which a target film overlying a stopping film is removed. A chemical reaction product is generated from at least one of the target film and the stopping film; this chemical reaction product is converted to a separate product. The separate product is exposed to ionizing radiation. The ionization current generated by the radiation is monitored as the target film is removed. A change in the ionization current corresponds to a change in concentration of the separate product, thereby indicating the endpoint of the film removal process. In the particular case of removal of a silicon dioxide film overlying a silicon nitride film by chemical-mechanical polishing, the reaction product is ammonia extracted from the polishing slurry. The ammonia is converted to ammonium chloride by a reaction with hydrogen chloride vapor. As the ammonium chloride, entrained in a carrier gas, is pumped through a detection unit, a change in the concentration thereof is detected by monitoring a change in the ionization current generated by a source of alpha particles.

Real-time control of chemical-mechanical polishing processing by monitoring ionization current

Detection of the endpoint for removal of a target film overlying a stopping film by removing the target film with a process that selectively generates a chemical reaction product (for example ammonia when polishing a wafer with a nitride film in a slurry containing KOH) with either the target or stopping film, and monitoring the level of chemical reaction product by threshold photoionization mass spectroscopy as the target film is removed.

Endpoint detection by chemical reaction and photoionization

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Poughkeepsie, NY, United States of America

Leping Li