UV/halogen metals removal process
AssigneesFSI International, Inc., Massachusetts Institute of Technology
InventorsAndrew Scott Lawing, Robert T. Fayfield, Herbert H. Sawin, Jane Chang
Life of this patent
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Abstract
A chlorine based dry-cleaning system appropriate for removing metal contaminants from the surface of substrate is described in which the metal contaminant is chlorinated and reduced to a volatile metal chloride by UV irradiation. The process parameters of chlorine gas partial pressure, temperature, ultraviolet bandwidth, and/or the sequence of exposure of the substrate to the chlorine containing gas and to the ultraviolet radiation are selected so as to effect substantial removal of the metal without excessive substrate roughening.
Claims23
A method for removing metal from a surface of a substrate using a chlorine containing gas comprising the steps of:
- providing a substate having metal thereon in a cleaning chamber;
- exposing the substrate to the chlorine containing gas supplied at a pressure of 1 Torr or less;
- and
- effectuating removal of metal from the surface of the substrate by irradiating the substrate and the chlorine containing gas with ultraviolet radiation that is not strongly absorbed by the chlorine containing gas and thereby does not cause substantial photolysis of the chlorine containing gas and the formation of atomic chlorine,
- wherein the cleaning chamber pressure is maintained at 1 Torr or less during the exposing and irradiating steps and the cleaning chamber is substantially free of atomic chlorine during the irradiating step.
A method for removing metal from a surface of a substrate using a chlorine containing gas comprising the steps of:
- providing a substrate with metal thereon in a cleaning chamber;
- exposing the substrate to a chlorine containing gas supplied at a pressure of 1 Torr or less;
- and
- irradiating the substrate and the chlorine containing gas with ultraviolet radiations the ultraviolet radiation not including wavelengths between 260 nm and 450 nm, to effectuate removal of metal from the surface of the substrate, the cleaning chamber pressure maintained at 1 Torr or less during the exposing and irradiating steps, wherein the cleaning chamber is substantially free of atomic chlorine during the irradiating step.
A method for removing metal from a surface of a substrate using a chlorine containing gas comprising the steps of:
- providing a substrate having metal thereon in a cleaning chamber;
- exposing the surface of the substrate to the chlorine containing gas supplied at a pressure below ambient pressure;
- and
- exposing the substrate and the chlorine containing gas to ultraviolet radiation from a lamp, the ultraviolet radiation not including wavelengths between 260 nm and 450 nm,
- whereby the exposing step effectuates removal of the metal from the surface of the substrate.
A method for removing metal from a surface of a substrate using a chlorine containing gas comprising the steps of:
- providing a substrate having a surface with metal thereon in a cleaning chamber;
- exposing the substrate to a chlorine containing gas supplied at a predetermined gas pressure below ambient, the chamber maintained at a predetermined chamber pressure below ambient;
- irradiating the substrate and the chlorine containing gas with ultraviolet radiation of one or more predetermined ultraviolet frequencies to form volatile metal chlorides having an oxidation number of 1 and effectuate removal of metal from the surface of the substrate, wherein
- the predetermined gas pressure below ambient, the predetermined chamber pressure below ambient and the one or more predetermined frequencies are selected such that at least some of the metal chlorides having an oxidation number of 1 that are formed are volatilized.
A method for removing metal from a surface of a substrate using a gas comprising a chlorine containing component, the method comprising the steps of:
- providing a substrate having metal thereon in a cleaning chamber;
- exposing the substrate to the gas, the partial pressure of the chlorine containing component 1 Torr or less;
- and
- effectuating removal of metal from the surface of the substrate by irradiating the substrate and the gas with ultraviolet radiation that is not strongly absorbed by the gas and thereby does not cause substantial photolysis of the chlorine containing component and the formation of atomic chlorine, wherein
- the cleaning chamber is substantially free of atomic chlorine during the irradiating step.
Dependencies are inferred from the claim text.