US 4,284,872 AGranted

Method for thermal testing and compensation of integrated circuits

AssigneeBurr-Brown Research Corporation

InventorJerald G. Graeme

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Abstract

Apparatus and method for compensating thermal drift of temperature sensitive circuitry in an integrated circuit by heating the temperature sensitive circuitry by applying power to a heating element in the integrated circuit, testing the temperature sensitive circuitry, and trimming a thin film resistor in accordance with the testing results. The heating element is an integrated resistor adjacent to or surrounding the temperature sensitive circuitry. The integrated circuit further includes a thin film compensation resistor which affects or determines the degree of temperature sensitivity of the temperature sensitive circuitry. As the temperature of the temperature sensitive circuitry is increased, testing apparatus is utilized to measure a temperature sensitive parameter of the temperature sensitive circuitry. Control signals indicative of the amount of required trimming of the thin film compensation resistor are produced in response to the testing to adequately compensate the thermal drift of the temperature sensitive circuitry. The control signals are utilized to control the operations of a laser which precisely trims the thin film compensating resistor by the required amount.

Claims15

Dependent claims

A method of trimming the value of an element of an integrated circuit to compensate for temperature sensitivity of the integrated circuit, the method comprising the steps of:

(a) applying an operating voltage to a temperature sensitive element of the integrated circuit;
(b) applying a powering voltage to a heating element in the integrated circuit for a sufficiently long time to heat said temperature sensitive circuitry to approximately a predetermined temperature, the heating element being disposed in the integrated circuit adjacent to said temperature sensitive circuitry;
(c) measuring a temperature sensitive electrical parameter of said temperature sensitive circuitry when said time elapses and substantially before thermal equilibrium is established in the integrated circuit;
(d) comparing the value of the measured temperature sensitive electrical parameter to a reference value;
(e) producing error information representative of the difference between the value of the measured electrical parameter and the reference value;
and
(f) laser trimming an element of the integrated circuit by an amount determined from said error information to adjust the temperature sensitive electrical parameter to a predetermined value, said element being determinative of said temperature sensitive electrical parameter.

4 more elements

Dependencies are inferred from the claim text.