Patent ID: 7663384
Filing Date: 2010-02-16
Classification: G01R

Abstract:
1. A method for measuring the area specific resistance of a metal plate comprising the steps of: providing a substrate; providing a metal plate on the substrate, wherein the metal plate comprises a top surface with a surface treatment and a back surface of bare untreated metal; providing a template mold on the top surface of the metal plate; applying silver paste on the top surface of the metal plate within the template mold; providing an oven; heating the metal plate in the oven at 120° C. for 10 minutes so that the silver paste is dried and molded; removing the template from the top surface of the metal plate; increasing the temperature in the oven to 960° C., or a point close to the melting point of silver, at least above 930° C. and retaining the temperature in the oven at this point for 1 hour, or a pre-determined period of time more than 30 minutes, so that the dried silver paste is sintered and turned into a silver foil, forming non-porous contact with the top surface of the metal plate; polishing the back surface of the metal plate; attaching a first wire and a second wire to the silver foil by a silver paste drop; spot welding a third wire and a fourth wire on the back surface of the metal plate within the covered area right under the silver foil; providing a power supply; connecting the first and third wires to the positive and negative electrodes of the power supply, respectively; providing a voltmeter; connecting the second and fourth wires to the positive and negative electrodes of the voltmeter, respectively; providing a current I from the power supply; increasing the temperature of the metal plate to 800° C. and retaining the temperature of the metal plate at this point for 30 minutes so that the silver paste drop is sintered and firmly attached to the silver foil; adjusting the temperature of the metal plate to a point determined by the practical applications for measurement and retaining the temperature of the metal plate at the point for measurement for a pre-determined period of time, depending on the temperature controlling ability of the oven; reading the voltage V from the voltmeter; taking a digitized image of the silver foil and calculating the area A of the silver foil by image analysis software; and calculating the area specific resistance of the metal plate based on the voltage V, the current I and the area A of the silver foil as V/(I/A).