Undesired material is removed from a chosen substrate by a process comprising the steps of (a) placing the substrate containing the undesired material in a cleaning chamber provided with cavitation-producing means; (b) introducing a liquefied gas, such as liquid carbon dioxide, into the cleaning chamber and contacting the substrate containing the undesired material with the liquid carbon dioxide at a temperature below its critical temperature; and (c) exposing the liquid carbon dioxide to the cavitation-producing means for a period of time sufficient to remove the undesired material from the substrate. The substrate containing the undesired material may optionally be contacted with carbon dioxide in the dense phase prior to and/or after the cavitation treatment to aid in removal of the undesired material. Further, spent liquid carbon dioxide may be treated to regenerate fresh liquid carbon dioxide which is recycled to the cleaning chamber. Other gases besides carbon dioxide which may be used include nitrous oxide, sulfur hexafluoride, and xenon.

Cleaning by cavitation in liquefied gas

A method of etching a tungsten film, comprising the steps of supporting a semiconductor substrate having a tungsten film thereon on a substrate support in an interior of a plasma etcher, supplying process gas to the interior of the plasma etcher, energizing the process gas into a plasma state, etching the tungsten film by exposing the substrate to the plasma, and heating the substrate to a temperature of at least 100° C. during the etching step. The etching step can include a low temperature main etch below 100° C. followed by a high temperature overetch above 100° C., the process gas including a fluorine containing gas during the main etch and a chlorine containing gas during the overetch. The tungsten film can be located over a dielectric film which serves as a stop layer during the etching step. The tungsten film can be pure tungsten and the dielectric layer can be a silicon oxide film having a thickness of 200 Å or less.

High temperature tungsten etching process

An improvement in a method for cleaning a CVD deposition chamber in a semiconductor wafer processing apparatus is described. The improvement comprises the treatment of fluorine residues in the CVD deposition chamber, left from a prior fluorine plasma cleaning step, by contacting such fluorine residues with one or more reducing gases which will react with the fluorine residues to form one or more gaseous or solid reaction products or a mixture of same.

Cleaning method for semiconductor wafer processing apparatus

A method and apparatus for reducing fluorine and other sorbable contaminants in plasma reactor used in chemical vapor deposition process such as the deposition of silicon oxide layer by the reaction of TEOS and oxygen. According to the method of the present invention, plasma of an inert gas is maintained in plasma reactor following chamber clean to remove sorbable contaminants such as fluorine. The plasma clean is typically followed by seasoning of the reactor to block or retard remaining contaminants. According to one embodiment of the invention, the combination of chamber clean, plasma clean, and season film is conducted before PECVD oxide layer is deposited on wafer positioned in the plasma reactor.

Decontamination of a plasma reactor using a plasma after a chamber clean

A process for gas-phase etching of actinide oxides from a substrate by using plasma power comprising the steps of: a) preheating actinide oxides on the substrate within a process chamber filled with fluorine-containing gas and exposing it to plasma power, and subsequently b) etching actinide oxides from the substrate using a plasma gas-phase reactant system.

Effective dry etching process of actinide oxides and their mixed oxides in CF4/O2/N2 plasma

The present invention provides a process for plasma cleaning and an improved gas mixture for use in a plasma cleaning process. The gas mixture of the present invention includes the normal process gases such as oxygen and carbon tetrafluoride. However, the mixture also includes a small percentage of a large mass inert gas such as Argon or Krypton. This large mass gas molecule mechanically removes any polymerized fluorocarbon that forms on the surface being cleaned thereby significantly enhancing the rate of etch or cleaning. It has been found that five to twenty percent of the inert gas is the preferred range and that ten percent produces optimum results.

Plasma etch enhancement with large mass inert gas

The gas mixture of the present invention includes the normal process gases such as oxygen and carbon tetrafluoride. However, the mixture also includes a small percentage of a large mass inert gas such as Argon or Krypton. It has been found that five to twenty percent of the inert gas is the preferred range and that ten percent produces optimum results.

Vu Q. Bui

Papers

Plasma etch enhancement with large mass inert gas

Plasma etching with a large molecular mass inert gas

Plasmaätzung in Anwesenheit von Edelgas mit hoher Molekularmasse