Micron Technology Incorporated

Micron Semiconductor, Inc.

Richard C Hawthorne

Li Li

Whonchee Lee

Randhir P Thakur

Pai Hung Pan

Kevin J Torek

Gurtej S Sandhu

Zhiqiang (Jeff) Wu

Donald L Westmoreland

Annette L Martin

Jonathan C Morgan

Elvia M Hawthorne

A method of forming a selected dielectric that includes the steps of contacting a suitable substrate having a silicon-containing layer with a gas mixture containing atomic nitrogen, nitric oxide and their reactive constituents at a pressure and temperature sufficient for effective dielectric layer formation for the selected dielectric layer.

Method for forming a dielectric

A surface having exposed doped silicon dioxide such as BPSG is cleaned with a solution that etches thermal oxide at least one-third as fast as it etches the exposed doped silicon dioxide, resulting in more thorough cleaning with less removal of the exposed doped silicon dioxide. Specific applications to formation of container capacitors are disclosed. Preferred cleaning solutions include about 46 parts ammonium fluoride, about 9.5 parts hydrogen fluoride, and about 8.5 parts ammonium hydroxide in about 100 parts water by weight; and about 670 parts ammonium fluoride and about 3 parts hydrogen fluoride in about 1000 parts water by weight. The latter solution is also useful in cleaning methods in which a refractory metal silicide is exposed to the cleaning solution such as in cleaning prior to spacer formation or prior to a gate stack contact fill, in which case about 670 parts ammonium fluoride and about 1.6 parts hydrogen fluoride in about 1000 parts water is most preferred.

Methods and etchants for etching oxides of silicon with low selectivity

A method of cleaning wafer surfaces includes providing a wafer surface and cleaning the wafer surface using at least hydrofluoric acid (HF) and an etch reducing component. The etch reducing component is from the group of (R),NOH wherein R&boxH;(C,-C,)alkyls, either straight or branch chained, and further wherein each R is independently a (C,-C,)alkyl, preferably a (C,-C,)alkyl, and more preferably one of tetra ethyl ammonium hydroxide (TEAH) and tetra methyl ammonium hydroxide (TMAH). A cleaning solution for use in cleaning a wafer surface includes an H,O diluted HF solution and an etch reducing component from the group above, preferably, TMAH. A system for performing an HF vapor cleaning process includes a vapor chamber for positioning a wafer having a wafer surface and means for providing an HF vapor to the vapor chamber. The HF vapor includes an inert carrier gas, an HF component, one of a water vapor or an alcohol vapor, and an etch reducing component. The etch reducing component may be from the group above, preferably, TMAH.

System for wafer cleaning

A method of forming a selected dielectric that includes the steps of contacting a suitable substrate having a silicon containing layer with a gas mixture containing atomic nitrogen, nitric oxide and their reactive constituents at a pressure and temperature sufficient for effective dielectric layer formation for the selected dielectric layer.

Disclosed is a process for cleaning silicon surfaces of native oxide films. The process utilizes fluorine containing cleaning materials such as anhydrous hydrofluoric acid to clean the oxide from the surface. A fluorine containing particulate matter which forms on the surface as a result of the fluorine containing cleaning materials is then removed by heating the surface to a high temperature. The process is conducted in a non-oxidizing ambient and is preferably conducted in a cluster tool so that the heating step can take place in the same chamber of the cluster tool as later metal deposition step.

Method for in situ removal of particulate residues resulting from

A method for use in the fabrication of semiconductor devices in accordance with the present invention includes providing a silicon nitride region and oxidizing a region of material in proximity to the silicon nitride region. The silicon nitride region is then hydrogenated and thereafter, the hydrogenated silicon nitride region is removed. The hydrogenation step may include immersing the silicon nitride region into pressurized boiling water and/or treating the silicon nitride region with pressurized water vapor and the removing step includes removing the hydrogenated silicon nitride region with hot phosphoric acid. The method may be used in a local oxidation of silicon process. Further, the oxidation of the material and the hydrogenation of the silicon nitride may be performed in the same pressurizable unit.

Method for removing silicon nitride in the fabrication of semiconductor

A surface having exposed doped silicon dioxide such as BPSG is cleaned with a vapor phase solution that etches thermal oxide at least one-third as fast as it etches the exposed doped silicon dioxide, resulting in more thorough cleaning with less removal of the exposed doped silicon dioxide. Specific applications to formation of container capacitors are disclosed. Preferred cleaning vapor phase solutions include about 1% water, about 5% hydrogen fluoride, and about 5% ammonias. The vapor phase solution is also useful in cleaning methods in which a refractory metal silicide is exposed to the cleaning vapor phase solution such as in cleaning prior to spacer formation or prior to a gate stack contact fill, in which case about 500 PPMV water, about 2% hydrogen fluoride, and about 2% ammonia is most preferred.

Selective etching of oxides

An ammonia-based etchant is employed, in dilute aqueous solution and preferably with a moderating agent, to etch polysilicon. Ammonium fluoride and ammonium hydroxide are the preferred etchants, with acetic acid and isopropyl alcohol the preferred moderating agents for use with the respective etchants. Dilute solutions of these etchants and their respective moderating agents provide a controllable, uniform polysilicon etch with reasonably good selectivity to undoped polysilicon over doped polysilicon. A dilute solution of ammonium fluoride and acetic acid provides particularly good selectivity. These etchants are applied to the etching of doped polysilicon upon which undoped hemispherical grain (HSG) polysilicon has been formed. The undoped HSG polysilicon is etched at a slower rate than the doped polysilicon which is etched at a greater but controllable and uniform rate. The result is a surface with greater total surface area contained within the same wafer area. This allows an increase in capacitance for capacitors formed with HSG polysilicon, without any increase in wafer area occupied thereby.

Method for controlled selective polysilicon etching

Disclosed is a method for the removal of a layer of photoresist material from a surface of a film located on an in-process integrated circuit wafer subsequent to etching the film through the photoresist material layer. The method disclosed herein comprises first, applying a layer of the photoresist material layer over the film, then patterning the photoresist material, etching the film, and finally, removing the photoresist material. The etch is preferably a wet etch conducted in a closed reaction chamber. The photoresist material removal can be conducted within the same closed reaction chamber as that in which the etch was conducted. Photoresist material removal is achieved by exposing the photoresist material to heated solvent vapors. One particularly advantageous vapor solvent comprises isopropyl alcohol. Subsequent to the photoresist material removal, the film is preferably subjected to cleaning, rinsing, and drying methods, all of which can be conducted within the same closed reaction chamber.

Photoresist removal process using heated solvent vapor

Disclosed is a method for dry cleaning a silicon surface on an in-process integrated circuit wafer which can be conducted in situ in a cluster tool or a reaction chamber where a previous etch or oxide removal step is conducted. The first step in the method is providing a silicon surface on the wafer which is to be cleaned of contaminates. Next, the wafer is located in a reaction chamber where the etch or oxide removal step is conducted. An adsorbent surface diffusion layer typically comprising a thin water or solvent layer in liquid state is then adhered to the silicon surface in the reaction chamber. Finally, the silicon surface is exposed to ultraviolet radiation and at least one gaseous cleaning agent while the surface diffusion layer is adhered on the silicon surface. A clean silicon surface results which does not exhibit the surface roughness typical of conventional dry cleaning processes.

Process for dry cleaning wafer surfaces using a surface diffusion layer

A method and system for fabricating semiconductor wafers is disclosed, wherein a rugged and/or smooth, atomically clean, semiconductor substrate is provided in a rapid thermal processing ('RTP') chamber. The substrate can be single crystal, polycrystalline or amorphous silicon. In one embodiment of the present invention, the substrate is cleaned by exposing it to at least one of CF.sub.4, C.sub.2 F.sub.2, C.sub.2 F.sub.6, C.sub.4 F.sub.8, CHF.sub.3, HF, NF.sub.6, and NF.sub.3 diluted with Ar-H.sub.2 at a temperature substantially within the range of 650.degree. C. to 1150.degree. C. for approximately 10 to 60 seconds in the chamber. Subsequently, the clean substrate is exposed to a first gas and energy generating a first temperature substantially within the range of 650.degree. C. to 1150.degree. C. in situ under substantially high vacuum for approximately 5 seconds to 20 seconds. Simultaneous to exposing the substrate to the first gas, a second gas comprising fluorine as an oxidizing agent, preferably NF.sub.3, is advanced by pulsing its introduction in situ under substantially high vacuum. By pulsing the introduction of the second gas, an on phase substantially in the range of 2 seconds to 5 seconds and an off phase substantially in the range of 5 seconds to 6 seconds is established. Preferably, the pulsing comprises two on and two off phases. In one embodiment of the present inventive method, the first gas comprises at least one of O.sub.2 and N.sub.2 O in combination with Ar to thereby fabricate a silicon dioxide layer superjacent the substrate.

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Nampa, ID, United States of America

Richard C Hawthorne