SU1525637A1 - Method of rejection of potentially unstable digital integral microcircuits - Google Patents

Abstract

The invention relates to a non-destructive testing technique and can be used to control the reliability and rejection of digital integrated circuits. The purpose of the invention is to increase the reliability of the rejection. Controlled and reference microcircuits 4 and 6 simultaneously feed the voltage of the power supply sources 10 and 11 and, through the measuring head 3, a predetermined test sequence from the program control unit 1 and the code influence unit 2. Current-to-voltage transducers 7.8 in the power rails and subtraction unit 9 form the difference signal of the current fluctuations of the power supply of both microcircuits. The fluctuation power of the differential signal is measured before and after heating the controlled chip 4 to the maximum non-destructive temperature using a microband amplifier 12, an adjustable amplifier 13, a quadratic detector 14 and the averaging unit 15. The result displayed on the indicator 16 is compared with the set value. 1 il.

Description

1525637

The invention relates to a technique of non-destructive testing, in particular to the diagnosis of digital integrated circuits, and can be used to control their reliability.

The purpose of the invention is to increase the reliability of rejection of potentially unstable digital integrated circuits by detecting defects that occur at elevated temperatures.

The drawing shows a diagram of a device for implementing the proposed method. five

In the drawing, the following notation is adopted: software control unit 1, code effect generating unit 2} measuring head 3, digital chip A (CMS) 20 being tested

heater 5, reference TsMS 6; current transducers 7 and 8 - voltage, subtraction lok 9, power sources 10 and 11, wideband amplifier 12i amplifier 13 with adjustable gain factor of 25; quadratic detector 14; - averaging block 15j indicator .16,

The arrangement works as follows.

The program control unit 1 provides you with the functions of receiving and storing a list of the commands of the monitoring and control program. Code action forming unit 2 2. The latter generates signals of code effect 5, and through test head 3 it is fed to test and reference 6 CMS. The measuring head contains the control elements for the controlled and reference Q digital circuits necessary to create the control conditions (buffer elements, load, matching, decoupling or conversion elements). The power is supplied from sources 10 and 11 to test A and reference 6 CMS. At the same time, the voltage from the transducers 7 and 8 is supplied to the subtraction unit 9, which produces a voltage directly proportional to the difference in the current consumption by both microcircuits. The voltage fluctuations are amplified by a wideband amplifier 12 and an amplifier 13 with adjustable gain.

Adjusting the gain ensures normal operation of the quadratic detector 1, averaging unit 15 and indicator 16. Time average 50

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In the case of reliability control, the fluctuation power is set equal to the action time of the input code action. To detect a faulty circuit, it is equal to the time the circuit is turned on after the test has started.

The method is carried out in the following sequence.

Controlled and reference microcircuits are supplied with supply voltage and test effects. With the help of transducers 7 and 8 current - voltage and subtractive unit 9, the difference of voltage signals, proportional to the fluctuations of the current consumption of micro, circuits is formed. The fluctuation power of the formed difference is measured before and after the microcircuits are heated to the maximum non-destructive temperature.

. The informative parameter is the difference in power fluctuations compared to which with a given value rejects unstable microcircuits. It is possible to carry out the method without using a reference chip. In this case, instead of the difference in voltage signals, a signal proportional to the fluctuations of the supply current of the controlled chip is used.

To determine the maximum non-destructive temperature, the following operations are performed: a known chip of this type is considered threshold, the maximum non-destructive temperature is determined by removing the dependence of the power of the supply current fluctuations on temperature. At the same time, the maximum non-destructive temperature is determined at the time of dependence.

Claims (1)

1. A method of rejecting potentially unstable digital integrated circuits, which consists in that the controlled and reference integrated circuits simultaneously supply the supply voltage and the input impulse effect, convert the fluctuations of the supply current of the controlled and reference circuits into voltage signals, form the signal difference . captures the voltage from the reference and controlled chips and measures the power 51525637. the fluctuation of the signal difference between the heating and after cooling of the control voltages and choose it as a quality integrated circuit and of an informative parameter, about a tl-and-result of comparing the difference, informative by the fact that, for the purpose of pomative, mathematical parameters with a given signi fi cantness of the reliability of the rejection, by reason, they reject potentially potentially unreliable integrated, unstable integrated circuits, microcircuits, heat controlled integrated circuit up to max-2, method of pop. 1, a non-destructive temperature is distinguished, and with the fact that the maximum is not kept under heating a given time-breaking temperature is determined by m, cool the controlled on-time saturation of the temperature of the grinding chip, measure the information on the power of current fluctuations Mathematical parameter, determine the power of the reference integral mino informative parameters in front of 151 chips.