RU2696360C1 - Method for non-destructive quality control of super-large-scale integrated circuits based on critical voltage value - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to microelectronics and can be used to ensure quality and reliability of ultra-large integrated circuits (ULIC). Essence: critical supply voltage is measured at normal and elevated temperature. ULIC software is preliminary programmed by a testing program for separate diagnostics of ULIC units. Critical supply voltage of the selected unit is measured by supplying single timing pulses at low supply voltage and outputting the result through the input/output unit at normal supply voltage. For representative sampling of ULIC, dependence of critical supply voltage on temperature in range 10÷85 °C is measured. Dependent on the curve is an information area limited by a straight line corresponding to the minimum operating voltage according to the specifications for this type of ULIC, and the curve of the measured dependence of the critical supply voltage on temperature. According to the area of this informative area, reliability of ULIC is evaluated.

EFFECT: technical result is possibility of controlling the quality and reliability of programmable ULIC type microcontrollers and microprocessors.

1 cl, 2 tbl, 1 dwg

Description

The invention relates to microelectronics, and in particular to methods for ensuring the quality and reliability of integrated circuits (ICs), and can be used to sort digital ICs according to the criterion of potential unreliability both at the production stage and at the input control at manufacturers of electronic equipment. There are a large number of non-destructive diagnostic methods for digital ICs, however, they are developed for specific types of ICs and are difficult to transfer to other types of ICs [1, 2, 3]. In addition, well-known methods do not take into account the features of super-large integrated circuits (VLSI) such as microcontrollers and microprocessors. The features of these VLSIs include the presence of blocks made by different technologies, the presence of several internal power supplies, voltage stabilizers, etc. Tests developed by manufacturers, such as JTAG (Joint Test Action Group; used as an association with a hardware interface for programming, testing and debugging printed circuit boards), allow you to monitor the performance of VLSI in certain conditions, but do not provide information about reliability. Development of diagnostic methods for VLSI type microcontroller is relevant.

Known methods for determining the potential reliability or comparing the reliability of ICs, based on measuring the critical supply voltage (KNI), are based on a sequential decrease in the supply voltage from nominal to a certain minimum value, at which the ICs still maintain functioning [1].

It is known the use of predictive control based on the method of critical supply voltage [2]. The method consists in lowering the supply voltage from the nominal value until when the first malfunction of the electronic device occurs while simultaneously monitoring it. For the critical supply voltage, the previous voltage value is taken, before which the first malfunction occurs. Numerous experiments on statistically significant samples of electronic devices have shown that such a parameter is informative with respect to latent defects such as leakage currents, instability of threshold voltages, and propagation delay of signals. The method is suitable for devices such as 74NS139, 74NS139 decoders, CMOS switch, digital potentiometers.

According to the patent No. 2365930 of the Russian Federation, IPC G01R 31/26, publ. 08/28/2009, there is a known method of rejecting semiconductor products, in which measure the KNI of the product at normal and elevated temperatures not exceeding the maximum temperature of the crystal IC, and select the IC from the calculation of the relative magnitude of the change in KNI.

But this method is applicable only for ICs consisting of one block. For the diagnosis of modern VLSI (microcontrollers and microprocessors) methods created for ICs of small and medium degree of integration are not suitable. There are several reasons for this. So microcontrollers can have a built-in power system that generates for individual VLSI units a supply voltage different from the supply circuit. It is also necessary to consider the presence of protective systems.

The technical task of the invention is to expand the functionality of the method for the diagnosis of integrated circuits with the possibility of non-destructive quality control and reliability of programmable VLSI microcontrollers and microprocessors.

The problem is solved by the claimed method.

A method of non-destructive testing of the quality of ultra-large integrated circuits by the value of the critical supply voltage, at which the critical supply voltage is measured at normal and elevated temperatures, characterized in that the VLSI type microcontroller or microprocessor is pre-programmed with a testing program with the ability to separately diagnose VLSI core, peripheral blocks, input block -information output, measure the critical supply voltage of the selected unit, with a minimum value of which is selected This unit maintains its normal functioning by supplying single clock pulses at a reduced supply voltage, and the result is output by subsequent clock cycles through an input / output unit at a normal supply voltage. For a representative VLSI sample, the temperature dependence of the critical supply voltage is measured in the range 10 ÷ 85 ° С in relation to the selected block, according to the dependencies, an informative region is defined limited by a straight line corresponding to the minimum permissible operating voltage in accordance with and specifications for a particular type of VLSI and the curve of the measured dependence of the critical supply voltage of the temperature, and on the area of the informative field estimate the reliability of VLSI microprocessor or microcontroller type of sample is higher, the longer the specified area.

FIG. 1 illustrates the study of the dependence of the critical VLSI power supply voltage on temperature and the allocation of an informative area.

The method of non-destructive quality control of VLSI, in particular, microcontrollers, according to the value of KNI is explained and carried out as follows.

The reliability of the microcontroller will be determined by the unit most susceptible to critical voltage. Using the testing program, it is possible to examine separately the various functional blocks of the microcontroller (core, ADC peripheral blocks, timer counters, analog comparator, etc.).

The computational operation is loaded into the microcontroller under study. According to the technical documentation, the processor performs it in one clock cycle of the clock signal, and during the same clock cycle writes the result to the register. Subsequent ticks from the register information is issued to the input / output port. Beats are given once, the processing of internal commands and the execution of arithmetic-logical operations occur at a reduced supply voltage, and the output through the input / output unit is normal. Thus, using the KNI method, it is established at what minimum supply voltage the microcontroller core can operate reliably.

To obtain a larger number of informative parameters on a representative sample of microcontrollers, the KNI of the unit with the smallest KNI is measured. KNI is measured at different temperatures within operating temperatures, for example, from plus 10 ° C to plus 85 ° C, at least in relation to the core of the microcontroller, and the dependence of the critical supply voltage on temperature is built. Based on this study, the effect of temperature on KNI is determined.

To verify and justify the method, a study of the dependence of KNI on temperature was performed for six samples of ATmega8a microcontrollers in the operating temperature range of 10 ÷ 85 ° С. For KNI, the voltage value is preceded by the voltage value at which a failure in the operation of the electronic circuit occurred. The results of the measurement of KNI for all samples are presented in table 1.

For the minimum allowable supply voltage, the value specified in the technical conditions for the studied microcontroller is 4.5 V. The experiment showed that the KNI of the ATmega8a microcontroller core has a traceable temperature dependence. Depending, as shown in FIG. 1 (depicts the study of sample No. 6), an informative region S is bounded by a straight line corresponding to the minimum permissible operating voltage in accordance with the technical conditions, and a curve of the measured temperature dependence of the KNI.

To evaluate and separate microcontrollers by reliability, for each sample, the area (in ° C × V) of the informative region S, bounded by a straight line corresponding to a voltage of 4.5 V, and the temperature dependence of the KNI on the temperature in the range from 10 ° C to 85 ° WITH. The values of the area of the informative area for all studied samples are presented in table 2.

The reliability of the microcontrollers from the sample will be the higher, the greater the area S of the informative area on the graph of the KNI versus temperature. This reliability assessment is explained as follows.

1. For the bulk MK, the area S has a value close to the average statistical value for the entire sample.

2. For less stable MK, the area S will be in the range from zero (since it will tend to the nominal value of the norm according to the technical conditions) to the average statistical value (sample No. 6 is most sensitive to undervoltage, see table 1).

3. For more resistant MK, the area S will be higher than the average value (this is MK No. 4 with greater reliability).

The inventive method allows quantitatively expressing the resistance of the VLSI blocks, in particular, the microcontroller, to lower the supply voltage in the operating temperature range from 10 ° C to 85 ° C.

A study using the KNI method to perform non-destructive quality control of VLSI at different temperatures allows us to identify the most sensitive to low voltage supply VLSI structural units, in particular, the core and peripheral blocks of the microcontroller, and then, based on the data obtained, diagnose and separate electronic devices for reliability.

List of cited documents:

1. Gorlov M.I. Diagnostics in modern microelectronics / M.I. Gorlov, V.A. Emelyanov, D.Yu. Smirnov / Minsk .: Integralpolygraph, 2011 .-- 375 p.

2. Almina N.A. Control of microelectronic devices by the method of critical supply voltages / N.A. Almina, V.Yu. Gavrilov, N.N. Nomokonova // Reliability and technical diagnostics, 2010. No. 1. - S. 115-120.

3. Vinokurov A.A. Diagnostics of integrated circuits by frequency characteristics at various supply voltages and temperatures / A.A. Vinokurov, M.I. Gorlov, A.V. Arsentiev, D.M. Zhukov // Bulletin of VSTU, 2014. - No. 3-1. - S. 128-132.

4. Gorlov M.I. RF patent No. 2365930. IPC G01R 31/26. The method of allocation of IP high reliability / M.I. Gorlov, N.N. Koziakov, E.A. Zolotareva; publ. 08/28/2009.

Claims (1)

A method of non-destructive quality control of ultra-large integrated circuits by the value of the critical supply voltage, at which the critical supply voltage is measured at normal and elevated temperatures, characterized in that the VLSI, at least of the type microcontroller or microprocessor, is pre-programmed with a testing program with the option of separately diagnosing the VLSI core , peripheral blocks, information input-output block, measure the critical supply voltage of the selected block, with the minimum value and whose selected unit maintains normal operation by supplying single clock pulses at a reduced supply voltage, and the result is output by subsequent clock strokes through an input / output unit at a normal supply voltage, for a representative VLSI sample, the temperature dependence of the critical supply voltage is measured in the range 10 ÷ 85 ° C in relation to the selected block, on the dependencies an informative area is defined, limited by a straight line corresponding to the minimum permissible operating voltage NIJ in accordance with the specifications for a particular type of VLSI and the curve of the measured dependence of the critical supply voltage of the temperature, and on the area of the informative field estimate the reliability of VLSI microprocessor or microcontroller type of sample is higher, the longer the specified area.

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