International Business Machines Corporation

Other

Clifford Owen Morgan, Iii

Leping Li

Cong Wei

James Albert Gilhooly

Chienfan Yu

Terrance M Wright

Erick G Walton

Matthew J Rutten

William Joseph Surovic

Walter Imfeld

Werner Moser

Matthias Kutter

Joseph Knee

Bruno Greuter

Heinz Stuenzi

Donald Francis Canaperi

Mahadevaiyer Krishnan

Rangarajan Jagannathan

Dennis A Schmidt

Philip Nicholas Theodoseau

Matthew Kilpatrick Miller

Robert B Lipori

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

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

A method for detecting the endpoint for removal of a target film overlying a stopping film by chemical-mechanical polishing using a slurry, by removing the target film with a polishing process that generates a chemical reaction product (for example ammonia when polishing a wafer with a nitride film in a slurry containing KOH) in the slurry, adding to the slurry a reagent which produces a characteristic result upon reacting with the chemical reaction product, and monitoring the slurry for the characteristic result as the target film is removed.

Endpoint detection by chemical reaction and reagent

Detection of the endpoint for removal of a target film overlying a stopping film by removing the target film with a process that selectively produces a gaseous 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, mixing the gaseous chemical reaction product present with a separate gas to form solid particles, and monitoring the amount of the solid particles as the target film is removed. Also, detection of a substance at very low concentrations in a liquid, by extracting the substance present as a gas from the liquid, mixing the gas with another substance to form solid particles, and monitoring the amount of the solid particles to detect the substance.

Endpoint detection by chemical reaction and light scattering

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. Also, detection of a substance at very low concentrations in a liquid, by extracting the substance present as a gas from the liquid and monitoring the gas to detect the substance.

A fluid collection apparatus having an accumulator for contacting a polishing surface of a polishing pad and collecting fluid from the polishing pad, a reservoir for receiving fluid from the accumulator, and a volume maintainer for maintaining a set volume of fluid in the reservoir.

Accumulator for slurry sampling

A colloidal silica slurry containing triethanolamine is used in a chemical mechanical polishing process to polish multiple material substrates, such as silicon wafers containing silicon oxide where a thin underlayer of silicon nitride is used as a stop layer. The colloidal silica slurry containing triethanolamine is capable of achieving an oxide to nitride selectivity during polishing up to a demonstrated ratio of 28:1.

Chemical mechanical polishing of multiple material substrates and slurry

A method and apparatus for Chemical-Mechanical Polishing of semiconductor wafers using various formulations of high viscosity slurry.

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Burlington, VT, United States of America

Clifford Owen Morgan, Iii