Methods and apparatus for allocating the measured noise and resistance of a thin-film resistor between the resistor proper and the contact pads therefor

Claim 1

A method of determining electrical noise figures for the thin-film portions and the thin film-contact pad interfaces of thin-film devices fabricated on an insulating substrate, comprising the steps of: fabricating three thin-film resistors, having different resistances, in proximate relation on the substrate; depositing a pair of conductive contact pads on each of said resistors, the areas of the interfaces between said contact pads and said resistors being equal for all of said resistors; by automatic measuring means, determining the resistance between the contact pads of each of said resistors, and storing the values of the resistances; by automatic measuring means, determining the noise voltage generated by each of said resistors during the application of a test potential between the contact pads thereof, and storing the values of the noise voltages; and by machine means, solving the equations: 2E2r2X2 + E2R12Y2 4N12r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 - 4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, where: R1, R2, and R3 are the resistance values measured in said resistance determining step; N1, N2, and N3 are the noIse voltage values measured in said noise determining step; E is the magnitude of the test potential which has been previously stored in the computer; r is the resistance of each of the thin film-contact pad interfaces; X is the noise figure for the thin film-contact pad interfaces; and Y is the noise figure for the thin-film portions of the resistors.

Claim 2

A method of determining electrical noise figures for the thin-film portions and the thin film-contact pad interfaces of thin-film devices fabricated on an insulating substrate, comprising the steps of: fabricating three thin-film resistors, having different resistances, in proximate relation on the substrate; depositing a pair of conductive contact pads on each of said resistors, the areas of the interfaces between said contact pads and said resistors being equal for all of said resistors; by automatic measuring means, determining the resistance between the contact pads of each of said resistors, and storing the values of the resistances; by automatic measuring means, determining the noise voltage generated by each of said resistors during the application of a test potential between the contact pads thereof, and storing the values of the noise voltages; and by machine means, solving the equations: 2E2r2X2 + E2R12Y2 4N12r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 - 4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, where: R1, R2, and R3 are the resistance values measured in said resistance determining step; N1, N2, and N3 are the noIse voltage values measured in said noise determining step; E is the magnitude of the test potential which has been previously stored in the computer; r is the resistance of each of the thin film-contact pad interfaces; X is the noise figure for the thin film-contact pad interfaces; and Y is the noise figure for the thin-film portions of the resistors.

Claim 3

A method of operating a digital computer to determine electrical noise figures for the thin-film portions and thin film-contact pad interfaces of thin-film devices fabricated on a substrate, wherein three thin-film resistors, having different resistance values, are fabricated on said substrate, and a pair of conductive contact pads is deposited on each of said resistors, with the areas of the interfaces between said contact pads and said resistors being equal for all of said resistors, which comprises: under the control of said computer, initiating a measurement of the resistance between the contact pads of each of said resistors, and storing the resulting resistance values, R1, R2, and R3, in the computer; under the control of said computer, initiating a measurement of the noise voltages generated by each of said resistors during the application of a test potential E between the contact pads thereof, and storing the values of the noise voltages N1, N2, and N3, corresponding to R1, R2, and R3, respectively; and solving, in said computer, the equations: 2E2r2X2 + E2R12Y2 -4N12r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 -4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, the value of E being previously stored in the computer, and where: r is the resistance of each of the contact pad-thin film interfaces; X is the noise figure for the contact pad-thin film interfaces; and Y is the noise figure for the thin-film portions of the resistors.

Claim 4

A method of operating a digital computer to determine electrical noise figures for the thin-film portions and thin film-contact pad interfaces of thin-film devices fabricated on a substrate, wherein three thin-film resistors, having different resistance values, are fabricated on said substrate, and a pair of conductive contact pads is deposited on each of said resistors, with the areas of the interfaces between said contact pads and said resistors being equal for all of said resistors, which comprises: under the control of said computer, initiating a measurement of the resistance between the contact pads of each of said resistors, and storing the resulting resistance values, R1, R2, and R3, in the computer; under the control of said computer, initiating a measurement of the noise voltages generated by each of said resistors during the application of a test potential E between the contact pads thereof, and storing the values of the noise voltages N1, N2, and N3, corresponding to R1, R2, and R3, respectively; and solving, in said computer, the equations: 2E2r2X2 + E2R12Y2 -4N12r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 -4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, the value of E being previously stored in the computer, and where: r is the resistance of each of the contact pad-thin film interfaces; X is the noise figure for the contact pad-thin film interfaces; and Y is the noise figure for the thin-film portions of the resistors.

Claim 9

A method of using a digital computer to allocate the electrical noise generated by thin-film devices fabricated on a substrate between the thin-film portions and the interfaces between the thin film and conductive contact pads overlaid on the film, comprising the steps of: fabricating three electrically and physically similar thin-film resistors on adjacent regions on said substrate, each of said resistors having two conductive contact pads overlaid thereon, the total thin-film area contacted by each of the pads being substantially equal for each one of said at least three resistors; under the control of said computer, measuring the electrical resistances R1, R2, and R3 of each of said resistors, and storing the values of said resistances in the computer; under the control of said computer, measuring the electrical noise voltages N1, N2, and N3 generated by each of said resistors during the application thereacross of a test potential E, and storing the values of said noise voltages in the computer; in said computer, calculating the resistance r of the contact pad-thin film interfaces according to the formula: Alpha 1 N12(R2 - R3) Alpha 2 N22(R3 - R1) Alpha 3 N32(R1 - R2) in said computer, calculating the noise Y allocable to the thin-film portions of said devices according to the formula: and; in said computer, calculating the noise X allocable to the contact pad-thin film interfaces on said devices according to the formula: X Square Root (1/2r2) ((N12/E2) (R1 + 2r)2 -Y2R12) where the value of E has previously been stored in said computer.

Claim 10

A method of using a digital computer to allocate the electrical noise generated by thin-film devices fabricated on a substrate between the thin-film portions and the interfaces between the thin film and conductive contact pads overlaid on the film, comprising the steps of: fabricating three electrically and physically similar thin-film resistors on adjacent regions on said substrate, each of said resistors having two conductive contact pads overlaid thereon, the total thin-film area contacted by each of the pads being substantially equal for each one of said at least three resistors; under the control of said computer, measuring the electrical resistances R1, R2, and R3 of each of said resistors, and storing the values of said resistances in the computer; under the control of said computer, measuring the electrical noise voltages N1, N2, and N3 generated by each of said resistors during the application thereacross of a test potential E, and storing the values of said noise voltages in the computer; in said computer, calculating the resistance r of the contact pad-thin film interfaces according to the formula: Alpha 1 N12(R2 - R3) Alpha 2 N22(R3 - R1) Alpha 3 N32(R1 - R2) in said computer, calculating the noise Y allocable to the thin-film portions of said devices according to the formula: and; in said computer, calculating the noise X allocable to the contact pad-thin film interfaces on said devices according to the formula: X Square Root (1/2r2) ((N12/E2) (R1 + 2r)2 -Y2R12) where the value of E has previously been stored in said computer.

Claim 11

A method of determining the noise generated across both the thin-film portion and the thin film-contact pad interfaces of a thin-film device, to aid in determining which of the plurality of processing steps utilized in the manufacture of the device is responsible for excessive noise observed therein, comprising the steps of: fabricating three thin-film resistors in proximate relation on an insulating substrate utilizing the same processes which were used to manufacture the device observed to have excessive noise; depositing a pair of conductive contact pads on each of said three resistors, the areas of the interfaces between said contact pads and said thin-film portions being the same for all of said devices; measuring, under the control of a digital computer, the electrical resistances of each of said resistors and storing the resulting resistance values R1, R2, and R3 in the digital computer; measuring, under the control of the digital computer, the noise voltages generated by each of said resistors during the application of a test potential E across the contact pads thereof, and storing the values of the noise voltages corresponding to R1, R2, and R3 as N1, N2, and N3, respectively; and solving, in said computer, the equAtions: 2E2r2X2 + E2i R12Y2 -4N12r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 - 4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, the value of E being previously stored in the computer, where: r is the resistance of each of the contact pad-thin film interfaces of the resistors; X is the noise figure for the contact pad-thin film interfaces of the resistors; Y is the noise figure for the thin-film portions of the resistors, whereby comparisons with desired values of X and Y can be made to determine whether the excessive noise is being caused by the thin-film fabrication steps or by the contact pad fabrication steps.

Claim 12

A method of determining the noise generated across both the thin-film portion and the thin film-contact pad interfaces of a thin-film device, to aid in determining which of the plurality of processing steps utilized in the manufacture of the device is responsible for excessive noise observed therein, comprising the steps of: fabricating three thin-film resistors in proximate relation on an insulating substrate utilizing the same processes which were used to manufacture the device observed to have excessive noise; depositing a pair of conductive contact pads on each of said three resistors, the areas of the interfaces between said contact pads and said thin-film portions being the same for all of said devices; measuring, under the control of a digital computer, the electrical resistances of each of said resistors and storing the resulting resistance values R1, R2, and R3 in the digital computer; measuring, under the control of the digital computer, the noise voltages generated by each of said resistors during the application of a test potential E across the contact pads thereof, and storing the values of the noise voltages corresponding to R1, R2, and R3 as N1, N2, and N3, respectively; and solving, in said computer, the equAtions: 2E2r2X2 + E2i R12Y2 -4N12r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 - 4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, the value of E being previously stored in the computer, where: r is the resistance of each of the contact pad-thin film interfaces of the resistors; X is the noise figure for the contact pad-thin film interfaces of the resistors; Y is the noise figure for the thin-film portions of the resistors, whereby comparisons with desired values of X and Y can be made to determine whether the excessive noise is being caused by the thin-film fabrication steps or by the contact pad fabrication steps.

Claim 13

A method of operating a digital computer to determine the noise generated across both the thin-film portion and the thin film-contact pad interfaces of a thin-film device, to determine which of a plurality of fabricating steps utilized in the manufacture of the device is responsible for excessive noise observed therein, using a thin-film circuit comprising three thin-film resistors fabricated in proximate relation on an insulating substrate by the same processes which were used to manufacture the device observed to have excessive noise, each of said resistors having a pair of conductive contact pads deposited thereon, the area of the interface between the contact pads and said thin film being the same for all three of said resistors, comprising the steps of: under the control of said computer, measuring the electrical resistance of each of said resistors and storing the resulting resistance values, R1, R2, and R3, in the digital computer; under the control of said computer, measuring the noise voltages generated by each of said resistors during the application of a test potential E across the contact pads thereof, and storing the values of the noise voltages corresponding to R1, R2, and R3 as N1, N2, and N3, respectively; and solving, in said computer, the equations: 2E2r2X2 + E2R12Y2 -4N12i r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 -4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, the value of E being previously stored in the computer, where: r is the resistance of each of the contact pad-thin film interfaces of the resistors; X is the noise figure for the contact pad-thin film interfaces of the resistors; Y is the noise figure for the thin-film portions of the resistors, whereby comparisons with desired values of X and Y can be made to determine whether the excessive noise is being caused by the thin-film fabrication steps or the contact pad fabrication steps.

Claim 14

A method of operating a digital computer to determine the noise generated across both the thin-film portion and the thin film-contact pad interfaces of a thin-film device, to determine which of a plurality of fabricating steps utilized in the manufacture of the device is responsible for excessive noise observed therein, using a thin-film circuit comprising three thin-film resistors fabricated in proximate relation on an insulating substrate by the same processes which were used to manufacture the device observed to have excessive noise, each of said resistors having a pair of conductive contact pads deposited thereon, the area of the interface between the contact pads and said thin film being the same for all three of said resistors, comprising the steps of: under the control of said computer, measuring the electrical resistance of each of said resistors and storing the resulting resistance values, R1, R2, and R3, in the digital computer; under the control of said computer, measuring the noise voltages generated by each of said resistors during the application of a test potential E across the contact pads thereof, and storing the values of the noise voltages corresponding to R1, R2, and R3 as N1, N2, and N3, respectively; and solving, in said computer, the equations: 2E2r2X2 + E2R12Y2 -4N12i r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 -4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, the value of E being previously stored in the computer, where: r is the resistance of each of the contact pad-thin film interfaces of the resistors; X is the noise figure for the contact pad-thin film interfaces of the resistors; Y is the noise figure for the thin-film portions of the resistors, whereby comparisons with desired values of X and Y can be made to determine whether the excessive noise is being caused by the thin-film fabrication steps or the contact pad fabrication steps.

Claim 17

A method for determining the noise contributions in a thin-film resistor, and its interfaces with external circuitry, comprising the steps of: fabricating three thin-film resistors having different resistances in proximate relation on an insulating substrate; attaching conductive means to said resistors which provide identical interface areas between said conductive means and each of said resistors; under the control of machine means, measuring the resistance of each of said resistors and storing in said machine means the resistance values R1, R2, and R3; under the control of machine means, measuring the noise voltages generated by each of said resistors during the application of a test potential, E, thereacross, and storing in said machine means the values of the noise voltages corresponding to R1, R2, and R3 as N1, N2, and N3, respectively; and by machine means, solving, the equations: 2E2r2X2 + E2R12Y2 -4N12r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 - 4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, the value of E being previously stored in said machine means, where r represents the resistance of each of the contact pad-thin film interfaces, and X and Y represent, respectively, the noise figure of said interface areas and that of said resistors external to said interface areas.

Claim 18

A method for determining the noise contributions in a thin-film resistor, and its interfaces with external circuitry, comprising the steps of: fabricating three thin-film resistors having different resistances in proximate relation on an insulating substrate; attaching conductive means to said resistors which provide identical interface areas between said conductive means and each of said resistors; under the control of machine means, measuring the resistance of each of said resistors and storing in said machine means the resistance values R1, R2, and R3; under the control of machine means, measuring the noise voltages generated by each of said resistors during the application of a test potential, E, thereacross, and storing in said machine means the values of the noise voltages corresponding to R1, R2, and R3 as N1, N2, and N3, respectively; and by machine means, solving, the equations: 2E2r2X2 + E2R12Y2 -4N12r2 - 4rR1N12 N12R12 2E2r2X2 + E2R1R2Y2 - 4N22r2 - 4rR2N22 N22R22 2E2r2X2 + E2R1R3Y2 - 4N32r2 - 4rR3N32 N32R32 for unknowns r, X, and Y, the value of E being previously stored in said machine means, where r represents the resistance of each of the contact pad-thin film interfaces, and X and Y represent, respectively, the noise figure of said interface areas and that of said resistors external to said interface areas.