Abstract: A method of reclaiming silicon wafers including a film removal process, a polishing process, and a cleaning process, wherein a heating/removal process for removing a silicon wafer surface part by heating at 150-300° C. for 20 minutes to 5 hours is further included between the film removal process and the polishing process is provided. The present invention provides a useful method of reclaiming silicon wafers that removes Cu not only deposited on a surface but also penetrated inside of a silicon wafer, and does not give Cu contamination inside of the silicon wafer.

Abstract: The polishing slurry contains monoclinic zirconium oxide particles having a crystallite size of 10 to 1,000 nm and an average particle diameter of 30 to 2,000 nm in an amount of 1 to 20 weight %, a carboxylic acid having three or more carboxyl groups in the molecule, and a quaternary alkylammonium hydroxide, and has a pH of 9 to 12. The method of reclaiming wafers comprises a step of polishing used test wafers by using the polishing slurry above and removing the films formed on the wafers and the degenerated layers formed on the wafer surfaces, a step of mirror-polishing at least one side of the wafers, and a step of cleaning the wafers.

Abstract: The polishing slurry contains monoclinic zirconium oxide particles having a crystallite size of 10 to 1,000 nm and an average particle diameter of 30 to 2,000 nm in an amount of 1 to 20 weight %, a carboxylic acid having three or more carboxyl groups in the molecule, and a quaternary alkylammonium hydroxide, and has a pH of 9 to 12. The method of reclaiming wafers comprises a step of polishing used test wafers by using the polishing slurry above and removing the films formed on the wafers and the degenerated layers formed on the wafer surfaces, a step of mirror-polishing at least one side of the wafers, and a step of cleaning the wafers.

Abstract: A method of reclaiming silicon wafers including a film removal process, a polishing process, and a cleaning process, wherein a heating/removal process for removing a silicon wafer surface part by heating at 150-300° C. for 20 minutes to 5 hours is further included between the film removal process and the polishing process is provided. The present invention provides a useful method of reclaiming silicon wafers that removes Cu not only deposited on a surface but also penetrated inside of a silicon wafer, and does not give Cu contamination inside of the silicon wafer.

Abstract: A method of specifying a Cu-contamination-causative step or steps in a Si wafer reclamation process including plural steps in combination, comprising: using p-type Si wafers, or p-type Si wafers and n-type Si wafers as monitor wafers, and performing a measuring operation for measuring the electrical resistance of the monitor wafers at least once before and after a single step or a series of successive steps during the Si wafer reclamation process. The present invention is capable of nondestructively, simply, and accurately detecting Cu that can contaminate Si wafers during a Si wafer reclamation process and is capable of specifying a Cu-contamination-causative process.

Abstract: A method of specifying a Cu-contamination-causative step or steps in a Si wafer reclamation process including plural steps in combination, comprising: using p-type Si wafers, or p-type Si wafers and n-type Si wafers as monitor wafers, and performing a measuring operation for measuring the electrical resistance of the monitor wafers at least once before and after a single step or a series of successive steps during the Si wafer reclamation process. The present invention is capable of nondestructively, simply, accurately detecting Cu that can contaminate Si wafers during a Si wafer reclamation process and of specifying a Cu-contamination-causative process.

Abstract: A method for reclaiming a wafer substrate material having a metallic film and a dielectric film includes a step for removing the entire metallic film and a part of the dielectric film with a chemical etching agent so as not to substantially dissolve the wafer substrate material itself, a step for removing the residual dielectric layer and the degenerated zone beneath the surface of the substrate by chemical-mechanical polishing, and a step for polishing at least one surface of the substrate.

Abstract: A process capable of reclaiming used semiconductor wafers with a reduced metallic contamination level on wafer surfaces. The process comprises the steps of removing one or more surface layers of the substrate by chemical etching; scraping off one surface of the substrate in small amount by mechanical machining; removing a damage layer, which has occurred due to the mechanical machining, by chemical etching; and polishing the other surface of the substrate into a mirror finish.

Abstract: A method of evaluating the quality of a silicon wafer is characterized by analyzing a silicon wafer by an infrared absorption spectrum, and then evaluating the quality of the silicon crystal based on an absorbance ratio represented by the following formula (1): {(Absorbance &agr;1 at an arbitrary wavenumber between 1055 and 1080 cm−1)−(Absorbance &agr;BL of base line)}/{(Absorbance &agr;2 at an arbitrary wavenumber between 1100 and 1120 cm−1)−(Absorbance &agr;BL of base line)}  (1) wherein absorbances &agr;1 and &agr;2 represent absorbances of the measured silicon wafer, and base line absorbance &agr;BL represents the absorbance of a base line of the measured silicon wafer, which is drawn from 1030 to 1170 cm−1. By using the quality evaluating method of the present invention, internal crystal defects of silicon can be precisely detected in a non-destructive manner.

Abstract: A process comprising removing surface layer materials from the wafer by inducing micro-fractures in the surface using a rotating pad and an abrasive slurry until all of the surface layer materials are removed; and chemically etching the surfaces of the wafer until all micro-fractures are removed therefrom. Edge materials are removed by abrasive tape. Wafer thickness reduction during recycling is less than 30 microns per cycle. One of the front and back surfaces of the wafer substrate is polished, any dots or grooves being on the non-polished side. The abrasive slurry contains more than 6 volume percent abrasive particles, and the abrasive slurry has a viscosity greater than about 2 cP at ambient temperature. The preferred pad comprises an organic polymer having a hardness greater than about 40 on the Shore D scale, optimally a polyurethane. The pressure of the pad against the wafer surface preferably does not exceed about 3 psi. Preferably, the chemical etching solution contains potassium hydroxide.

Abstract: A method of reclaiming a substrate wafer and a reclaimed substrate wafer. A semiconductor wafer having external layers from previous processing is reclaimed by etching the external layers and cup-wheel grinding an active surface of the wafer to remove semiconductor components such as diffused regions. Either the active surface or the backside of the wafer is then polished to a mirror finish to provide a highly crystalline surface. The cup-wheel grinding produces a pinwheel surface roughness pattern and is accomplished by grinding the wafer with a cup-shaped grinding wheel having an axis of rotation parallel to but offset from an axis of rotation of the wafer. Preferably, the rim of the cup-shaped grinding wheel always passes over the axis of rotation of the wafer.