JP2000266710A - Circuit board deterioration diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve diagnosis precision and reliability by using a difference between an heating tendency to a power source voltage in a normal time and that in a deteriorated time for diagnosing deterioration of a mounted circuit board in a device using an electronic/electric part. SOLUTION: A thermal analyzer 1 is constructed of a heating characteristic extracting device 11 and a diagnostic means 12. A thermal analysis means 111 in the heating characteristic extracting device 11 inputs a transitionally varying thermal condition (a) of a mounting surface when a mounted circuit board is exited/actuated, and extracts a characteristic amount of the transitionally varying thermal condition. A heating characteristic extracting means 112 inputs an extracted characteristic amount (b) and connected to a characteristic data base 113 for inputting a normal value data (c) of a heating characteristic. From the characteristic amount (b) tendency data to a power source voltage and the normal value data (c), a heating characteristic (d) is extracted so as to be stored in the characteristic data base 113. The diagnostic means 12 inputs heating characteristic history data and a life characteristic data (e) outputted from the characteristic data base 113 so as to estimate presence/absence of deterioration and a life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal analysis of a mounted circuit board and mounted components, and more particularly to a circuit board deterioration diagnosis apparatus which diagnoses deterioration from a characteristic amount of a thermal state.

[0002]

2. Description of the Related Art Conventionally, deterioration diagnosis by thermal analysis of a mounted circuit board has been disclosed in Japanese Patent Application No. 9-168925 (name of invention:
Method and apparatus for diagnosing deterioration of mounting board) and Japanese Patent Application No. Hei 10-0
18864 (invention name: thermal image analysis method and apparatus) has already been filed. In both cases, the diagnosis is made based on a phenomenon that the heat generation state of the mounting surface changes due to deterioration of the mounted circuit board (also simply referred to as a mounted board) due to aging.

The former quantifies a fractal dimension (a quantified complexity of undulation of an image density curved surface of a thermal image) obtained from a temperature or a thermal image in terms of a change in heat generation, and quantifies the fractal dimension by a correlation coefficient or the like, and degrades from the trend. Is a device for diagnosing. The latter is a thermal analysis device that optimally divides the scale for calculating the fractal dimension and calculates the fractal dimension within the divided scale range in order to detect changes in the heat distribution from the thermal image with high sensitivity. It is.

[0004]

In these two prior inventions, the mounted circuit board is deteriorated, but when the influence does not appear as a large change in heat generation, there is a drawback that detection of the deterioration is limited. there were. Therefore, in order to further improve the effects of the first two inventions, it was necessary to generate a large change in heat generation between a normal state and a deteriorated state.

Accordingly, the present invention utilizes the tendency of heat generation for different power supply voltages in a normal state and a deteriorated state in a circuit board using an electric component or an electronic component, and extracts a maximum difference in temperature or the like (a large amount) from the tendency difference. It is an object of the present invention to provide a circuit board deterioration diagnosis apparatus which detects, with high sensitivity, deterioration of a component or a mounted circuit board on which the component is mounted from various amounts characterizing a change in heat generation, and improves diagnosis accuracy.

[0006]

The circuit board deterioration diagnosis apparatus of the present invention utilizes the fact that the tendency of heat generation with respect to a power supply voltage differs between a normal state and a deterioration state with respect to an apparatus using electronic parts or electric parts. It is characterized by diagnosing the deterioration of a mounted circuit board on which electronic components or electrical components are mounted,
Utilizing the fact that the tendency of heat generation with respect to power supply voltage differs between normal time and deterioration, and using the amount of heat generation characteristics obtained from the maximum difference as a deterioration diagnosis index, high deterioration detection sensitivity and highly accurate diagnosis are possible. become.

[0007] The circuit board deterioration diagnosis apparatus of the present invention comprises:
Thermal analysis means for inputting thermal state temporal data of the mounting surface when the mounting circuit board is energized or operated, and extracting the characteristic amount of the thermal state temporal data, and variable power supply voltage supplied to the mounted components of the mounting circuit board Means for inputting the characteristic amount when energized or operated at each power supply voltage value from the thermal analysis means, and means for representing the characteristic amount trend data for the power supply voltage and the normal state, and the mounting circuit board from the characteristic amount trend data for the power supply voltage And a heat generation characteristic extracting means for extracting heat generation characteristics with respect to the power supply voltage of the power supply voltage. From the thermal analysis means, and based on the characteristic data trend data for the power supply voltage and the "characteristic trend data for the power supply voltage" indicating a normal state, the power of the mounted circuit board is determined. Can extract heat generation characteristic with respect to voltage, it is possible to extract the quantities of heat generation characteristics obtained from the maximum difference in the time degradation and normal.

Further, in the circuit board deterioration diagnosis apparatus of the present invention, the heat generation characteristic extracting means for extracting the heat generation characteristic of the mounted circuit board with respect to the power supply voltage from the characteristic amount tendency data with respect to the power supply voltage, and the heat generation characteristic extraction means. A characteristic database for storing heat generation characteristics and storing history data and life characteristic data of the extracted heat generation characteristics, a diagnosis unit for inputting the data stored in the characteristic database and estimating whether or not the mounted circuit board has deteriorated and estimating the life, As a diagnostic index, the heat generation characteristics extracted by the heat generation characteristic extraction device can be used to perform “presence / absence and life estimation” of the mounted circuit board. Is improved.

Further, the circuit board deterioration diagnosis apparatus of the present invention is characterized in that "the tendency data of the characteristic amount with respect to the power supply voltage" indicating the normal state of the heat generation characteristic to be extracted and "the tendency of the characteristic amount with respect to the power supply voltage" of the mounted circuit board used over time. It is characterized by the maximum difference between data, so that "the trend data of the characteristic amount with respect to the power supply voltage" indicating the normal state and "the trend data of the characteristic amount with respect to the power supply voltage" of the mounted circuit board used over time.
It is possible to provide a diagnostic device that can extract the maximum difference amount between the two and uses the maximum difference amount as a diagnostic index. Here, the normal state means a normal state of the mounted circuit board to be diagnosed or a normal product of the same type as the mounted circuit board.

Further, the circuit board deterioration diagnosis apparatus of the present invention is characterized in that the heat generation characteristics extracted by the heat generation characteristic extraction device are represented by "characteristic tendency data with respect to the power supply voltage" indicating a normal state and "power supply voltage of a mounted circuit board used over time. The characteristic amount is defined as all the differences between the characteristic amount tendency data and the characteristic amount tendency data with respect to the power supply voltage indicating the normal state. , The amount of difference between the “trend data” and the diagnostic device using the amount of difference as a diagnostic index can be provided.

Further, the circuit board deterioration diagnosis apparatus according to the present invention is characterized in that the heat generation characteristic extracted by the heat generation characteristic extraction apparatus is "characteristic tendency data with respect to the power supply voltage" indicating a normal state, and the "power supply It is characterized by the power supply voltage width when the amount of difference between "extremely small amount of trend data with respect to voltage" is fixed, and "Tendency data of characteristic amount with respect to power supply voltage" indicating a normal state and mounted circuits used over time It is possible to provide a diagnostic apparatus that can extract the power supply voltage width when the amount of difference between the “extremely small amount of trend data with respect to the power supply voltage” of the substrate is constant and uses the power supply voltage width as a diagnostic index.

Further, the circuit board deterioration diagnosis apparatus according to the present invention is characterized in that the heat generation characteristic extracted by the heat generation characteristic extraction apparatus is represented by “characteristic tendency data with respect to the power supply voltage” indicating a normal state, and the “power supply It is characterized by the power supply voltage value that gives the maximum difference between the `` characteristic amount trend data on voltage '' and the `` characteristic amount trend data on power supply voltage '' indicating a normal state and the `` mounting circuit board '' It is possible to provide a diagnostic apparatus that can extract a power supply voltage value that gives the maximum difference amount between “the trend data of the characteristic amount with respect to the power supply voltage” and that uses the power supply voltage value as a diagnostic index.

Furthermore, the circuit board deterioration diagnosis apparatus of the present invention provides a heat characteristic extracted by the heat characteristic extracting device in a "change amount of characteristic data tendency data with respect to a power supply voltage" indicating a normal state and a mounted circuit board which has been used over time. Since it is characterized by "the amount of change in the tendency data of the characteristic amount with respect to the power supply voltage", the "amount of change in the tendency data of the characteristic amount with respect to the power supply voltage" indicating a normal state and the "power supply voltage of the mounted circuit board used over time" The amount of change in the tendency data of the characteristic amount with respect to "" can be extracted, and a diagnostic apparatus using the amount of change as a diagnostic index can be provided.

Further, the circuit board deterioration diagnosis apparatus of the present invention is characterized in that the heat generation characteristic extracted by the heat generation characteristic extraction device is represented by "characteristic tendency data on power supply voltage" indicating a normal state and "power supply voltage of a mounted circuit board used over time. The characteristic data for the power supply voltage, which represents the normal state, is characterized by the characteristic amount for the power supply voltage of the mounted circuit board used over time that gives the maximum difference between the characteristic data for the ”And“ Amount of characteristic for power supply voltage ”of a mounted circuit board that has been used over time that gives the maximum difference between“ Tendency data of characteristic amount with respect to power supply voltage ”of the mounted circuit board that has been used over time, and the characteristic amount can be used as a diagnostic index. The diagnostic device described above can be provided.

Further, in the circuit board deterioration diagnosis apparatus of the present invention, the heat generation characteristic with respect to the life consumption rate obtained by normalizing the life characteristic data stored in the characteristic database by the failure occurrence time of the mounted circuit board. The life characteristics data stored in the characteristics database is normalized to the failure occurrence time of the mounted circuit board, and this is used as the heat generation characteristic for the life consumption rate, and used as a characteristic model for life estimation based on the heat generation characteristics. can do.

Further, in the circuit board deterioration diagnosis apparatus according to the present invention, the presence or absence of deterioration by the diagnosis means is determined by the threshold value determination of the heat generation characteristic, and the mounted circuit boards to be diagnosed vary depending on the same kind of product or measurement environment conditions. The heat generation characteristic is represented by a probability distribution, and a predetermined error width determined from the probability distribution is used as a threshold value. When the heat generation characteristic of the mounted circuit board to be diagnosed varies under the same kind of product or under measurement environment conditions is represented by a probability distribution, and a predetermined error width determined from the probability distribution is used as a threshold value, and when it is not statistically normal (deterioration)
Can be determined.

Further, the circuit board deterioration diagnosis apparatus of the present invention determines the life consumption rate B of the mounted circuit board which has been used for A hours from the life characteristics by estimating the life by the diagnosis means. Since the remaining life of the mounted circuit board is estimated from a mathematical expression represented by {(1 / B) -1}, the life estimation by the diagnostic means is performed using the A circuit over time based on the life characteristic. By determining the life consumption rate B of the board and applying the equation of the remaining life, it becomes possible to estimate the remaining life of the mounted circuit board from the heat generation characteristics.

Further, the circuit board deterioration diagnosis apparatus of the present invention provides a mounting surface when a mounting circuit board is energized or operated with a power supply voltage value obtained from a heating tendency of a power supply voltage which differs depending on whether the mounting circuit board is normal or deteriorated. Thermal analysis means for inputting the thermal state temporal data and extracting the characteristic amount of the thermal state temporal data, and a characteristic amount extracted by the thermal analysis means and comparing and comparing the characteristic amount and the deterioration data with the mounting circuit board And a deterioration mode judging means for judging a deterioration mode of the mounting circuit board. By inputting the time-dependent data of the thermal state of the mounting surface in the case of the above, it is possible to extract the characteristic amount of the “time-dependent data of the thermal state”. Extraction Rukoto can. In addition, since the characteristic amount extracted by the thermal analysis unit is input and the characteristic amount is compared with the deterioration data to determine the deterioration mode of the mounted circuit board, the deterioration mode can be specified.

Further, the circuit board deterioration diagnosis apparatus of the present invention provides a mounting circuit having a deterioration mode in which the deterioration data is equal to or more than the variation in the characteristic amount between "measurement environmental conditions of thermal state" or "between normal products of the same type". A first deterioration mode determining unit that determines that there is a significant difference when the feature amount of the substrate is changed, determines that there is no significant difference when there is no change, and obtains result A; If the characteristic amount of the “same product as the mounted circuit board” has changed more than the amount of variation, it is determined to be “significantly different”, and if not changed, it is determined to be “no significant difference” and the result B A second deterioration mode determining means, and a third deterioration mode for determining the deterioration mode by comparing the result A and the result B with the result A and the result B, and comparing the result A with the result B. And a judgment means. It is not necessary to determine a numerical interpretation amounts improves the robustness of the deterioration determination, and to a good even in the results of each condition by testing, allowing the determination of high accuracy by the combination study.

Further, the circuit board deterioration diagnosis apparatus of the present invention is characterized in that it has a heat generation characteristic extracting device for only a specific mounted component on the mounted circuit board, so that the mounted component is not destroyed. Can be diagnosed.

Further, the circuit board deterioration diagnosis apparatus according to the present invention is characterized in that the apparatus has a heat generation characteristic extraction device for setting a characteristic amount to a dimensional change rate or a dimensional steady value of a heat distribution or a temperature change rate or a steady temperature of a mounted component. Therefore, it is possible to quantify the characteristics of the aging characteristics of the thermal state and improve the reliability of the device.

That is, the circuit board deterioration diagnosis apparatus of the present invention is a method for judging deterioration or failure of a printed circuit board or component parts based on the aging of temperature due to heat generated in the operation state of the printed circuit board. By operating between the maximum voltage and the minimum voltage with respect to the rated voltage and measuring the temperature at each voltage, it is possible to detect aging which could not be observed conventionally.

It is also an embodiment of the present invention to detect the temperature based on the fractal dimension of the temperature distribution density image.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a circuit board deterioration diagnosis apparatus according to the present invention will be described.

An embodiment of the present invention will be described below with reference to a functional block diagram shown in FIG. In the mounted circuit board on which the electronic / electric components are mounted, the thermal analysis unit 111 inputs the transiently changing thermal state a of the mounting surface when the mounted circuit board is energized or operated, and calculates the characteristic amount of the transiently changing thermal state. It is a means to extract.

The heat generation characteristic extracting means 112 includes
1, the characteristic amount b extracted by the thermal analysis means 111 is input, and the characteristic value b is connected to the characteristic database 113, and normal value data c of the heat generation characteristic is input from the characteristic database 113. Then, a heat generation characteristic d is extracted from the tendency data of the characteristic amount b with respect to the power supply voltage and the normal value data c,
The data d is stored in the characteristic database 113.

The characteristic database 113 is connected to the exothermic characteristic extracting means 112 and stores exothermic characteristic data and life characteristic data. The heat analysis unit 111, the heat generation characteristic extraction unit 112, and the characteristic database 113 constitute the heat generation characteristic extraction device 11.

The diagnosis means 12 is a means for inputting the "history data of heat generation characteristics and life characteristics data" e output from the characteristics database 113 and performing the "estimation of deterioration and life estimation" f. The diagnostic means 12 operates in conjunction with each other to configure the thermal analysis device 1.

(Processing Step 1) The thermal analysis apparatus 1 inputs a transiently changing thermal state a of the mounting surface when the circuit board is energized or operated, and extracts a characteristic amount b of the transiently changing thermal state a. . In this case, the mounted circuit board refers to a board on which electric / electronic parts are mounted and an electronic / electric circuit is formed by these parts.

FIG. 2 is an example of a schematic diagram showing a mounted circuit board. The packages IC01 to IC05 are components including a semiconductor integrated circuit chip, and indicate a package including all semiconductor-related integrated circuit chips. The resistors R01 to R03 and the capacitors C01 and C02 are electronic components mounted on the board B01.

In this embodiment, when referring to the thermal state of the mounting surface of the mounted circuit board, it includes not only the entire board B01 but also a partial area AR1 and one component as shown in FIG. The thermal state a of a partial area of the mounting surface such as the area AR2 may be used. In other words, not only the whole mounted circuit board but also a part thereof is included.

Here, in the case of the area AR2, since there is only one component, it means that the diagnosis is performed on the components constituting a part of the circuit in the mounted state. That is, in the case of AR2, the extraction and diagnosis of the heat generation characteristic of the mounted circuit board means the extraction and diagnosis of the heat generation characteristic of the mounted component.

As shown in FIG. 3, when it is desired to diagnose not a component mounted on a mounting circuit board in advance but a component alone, the component (FIG. 3 exemplifies the semiconductor integrated circuit package IC06) is energized. Or a board B mounted on the board after wiring configuration if necessary
02 is included in the mounting circuit board.

That is, as long as the electric / electronic parts are mounted on the board (with or without soldering connection), all of these are meant in the mounted circuit board and the present embodiment.

Next, the characteristic amount b is a dimensional change rate of the heat distribution, a dimensional steady value, a temperature change rate of the mounted component, and a steady temperature. The dimension change rate and the stationary dimension are the same as the conventional one. In addition, the present embodiment can be implemented by using another method and apparatus that can extract a dimensional change rate and a dimensional steady-state value as a characteristic amount of a transiently changing heat distribution.

The concept of the feature amount b will be described with reference to FIGS.

FIG. 4 is a graph for specifying the measurement time point for measuring the temperature at the time when a certain time has elapsed after the printed circuit board is energized.
N) to the time t5, and after the time t5, the temperature rise FT of the mounted component when operated by supplying an input signal or the like is schematically (illustration for illustration). The feature of this schematic diagram is that the temperature further rises after time t5.

The temperature change rate is a time change rate of the temperature T. It can be calculated in any time range in which the temperature T changes with respect to the elapsed time t. The recommendation is the temperature change rate near the rise of the temperature (because the influence of the ambient temperature is small), but any time range may be selected as long as the time changes.

For example, the vicinity of the temperature rise refers to a range in which the linearity of the temperature change with respect to time is maintained (approximately t1 to t1).
(during t3). In this range, the temperature data is approximated by linear least squares, and the slope of the approximate line XA is defined as a temperature change rate θA. Alternatively, a time range in which the temperature changes, such as t1 to t4 and t2 to t4, may be selected, and the temperature data may be linearly least-squares-approximated in that range, and the slope of the approximate line may be used as the temperature change rate. Further, the temperature change rate θB may be selected from the approximate straight line XB between the operation start points t5 and t6. Note that the time range for calculating the temperature change rate is not limited to FIG.

Next, the steady temperature is the temperature when the temperature reaches the steady state. In FIG. 4, there are two steady states, and the steady temperatures are TA and TB. In practice, the average value near the steady state may be used. This steady temperature may be a steady value of the temperature rise from the ambient temperature.

The concepts of the dimension change rate and the dimension steady value are the same as those in the related art. The heat distribution is quantified by the fractal dimension constant, and the overwave change of the heat distribution is also expressed as the change of the fractal dimension. In that case, the time change rate of the fractal dimension is called a dimension change rate. A value when the fractal dimension reaches a steady state in time is called a dimension steady value.

Referring to FIG. The heat distribution on the mounting surface, which changes transiently when the mounting circuit board is energized or operated, is quantified by the fractal dimension FD. Quantification is possible with conventional methods. FIG. 5 shows a quantified conceptual diagram. A pattern F1 in which the fractal dimension FD decreases, a pattern F2 in which the fractal dimension FD increases, and a pattern F3 in which the fractal dimension FD increases after a certain delay time are shown under a certain operating condition of the mounted circuit board. However, the pattern is not limited to these three, but is merely an example.

With respect to these patterns, for example, the dimensional change rates are the linear approximation lines XC and XD obtained by linear least-squares approximation between times t7 and t9 near the rise, and the approximation lines XE and XD between t10 and t12. Is the dimensional change rate. This is a recommended range, as is the case with the rate of temperature change. However, as in the case of the temperature change rate, an arbitrary time range may be generally selected. For example, t8 to t9, t11 to
For example, during t12. Furthermore, since the fractal dimension FD also changes from the time t13 at which the heat generation changes by changing the operating conditions, in this case, the gradient θF of the approximate straight line XF between the times t13 and t14 can be used as the dimensional change rate. It is needless to say that the time range for calculating the dimensional change rate is not limited to FIG.

FIG. 5 is a graph showing fractal dimensions measured at three different scales, and FIGS. 6 and 7 are graphs of actual measured values. The dimensional steady values are YC, YD, Y in FIG.
It is a fractal dimension FD value indicated by E and YF. Actually, the average value near the steady state may be used. FIGS. 6 and 7 show examples of fractal dimension FD data obtained by quantifying transient changes in heat distribution by a conventional method and apparatus. F4, F5, and F6 are data calculated by dividing the scale range for calculating the fractal dimension. This scale division method is the method disclosed in the conventional method and apparatus. FIG. 6 is a fractal graph of a normal IC and a deteriorated IC with respect to Vmin to Vmax.

(Processing step 2) Heat generation characteristic extracting means 11
In step 2, heat generation characteristics are extracted.

First, target data for obtaining heat generation characteristics will be described. The target data is an output value of the thermal analysis unit 111. This output value is obtained by making the power supply voltage supplied to the mounted components of the mounting circuit board variable, and extracting the thermal state a of the mounting surface that changes transiently when energized and operated at each power supply voltage value by the thermal analysis unit 111. These are all features. These become trend data of the characteristic amount b with respect to the power supply voltage.

FIG. 8 schematically shows the tendency of the characteristic amount P with respect to the power supply voltage V.

In FIG. 8, a curve N indicates a tendency when the mounted circuit board is normal, and a curve AN indicates a tendency of the mounted circuit board used over time extracted by the thermal analysis means 111. Here, the curve N may be replaced with a normal product of the same type as the mounted circuit board. The curve AN is created by plotting the characteristic amount b with respect to each power supply voltage V on a graph. The power supply voltage ranges from the minimum power supply voltage Vmin to the maximum rated voltage V at which the mounted component can operate.
max. The data c of the normal value curve N in FIG. 8 is extracted in advance by the thermal analysis unit 111. This data is stored in the characteristic database 113 in advance, and the normal value data c is extracted from the characteristic database 113 when the heat generation characteristic extracting unit 112 operates.

The actual data of FIG. 8 is shown in FIGS.
9 to 13 are actual examples of fractal dimension graphs of specific operational amplifiers, and it can be seen that a difference in fractal dimension value between a normal component and a deteriorated component appears at a specific operating voltage.

FIG. 10 shows the mounting circuit board of FIG.
Operates at V, 13V, 15V (input signal is square wave +10
This is actual data plotting a temperature change rate P2 extracted from a transiently changing temperature on the package surface of a semiconductor integrated circuit (here, an operational amplifier W is used) when -10V and 200 mHz are applied.

FIG. 9 shows an operational amplifier W and a resistor R1 (2M
Ω), R2 (2 KΩ), capacitor C1 (capacitance 0.
1 F or 0.22 F).

FIG. 11 shows the mounting circuit board of FIG.
Operates at V, 13V, 15V (input signal is square wave +10
This is actual data obtained by plotting the steady-state temperature P3 extracted from the transiently changing temperature on the package surface of the semiconductor integrated circuit when (−10 V, 200 mHz) is applied (a temperature rise value from the ambient temperature is plotted).

FIG. 12 shows the mounting circuit board of FIG.
When operated at V, 13V, and 15V, the dimension change rate P4 is extracted from the heat distribution of the entire circuit board that changes transiently,
It is a plot. FIG. 13 is a plot of the dimensional steady-state value P5 extracted from the heat distribution of the entire circuit board that changes transiently when the mounted circuit board of FIG. 9 is operated at 9 V, 11 V, 13 V, and 15 V.

In FIGS. 10 to 13, the conditions of each data are as follows. A: When a normal semiconductor integrated circuit and a capacitor with a capacitance of 0.1 μF are mounted B: A normal semiconductor integrated circuit and when a capacitor with a capacitance of 0.22 μF is mounted C: A semiconductor integrated circuit with a deteriorated product 1 Capacitance 0.22μF
D: deteriorated product 2 semiconductor integrated circuit, capacitance 0.22 μF
The power supply voltage and the input signal are turned on under the conditions at the time of mounting the capacitor, the thermal state is measured (measurement is performed at intervals of 15 seconds), and the characteristic amount is extracted by the thermal analysis unit 111.

Further, the deteriorated semiconductor integrated circuit is one that has been deteriorated by being installed in a high-temperature, high-humidity constant-temperature bath for a long period of time while being energized. (Since there are two deteriorated products, they are distinguished from deteriorated products 1 and 2.) As is clear from FIGS. 10 to 13, when the semiconductor integrated circuit deteriorates, the heat generation characteristics (A, B data And a big difference is seen between other data.) The present invention takes advantage of this feature. FIG.
FIGS. 0 to 13 show actual data of the operational amplifier as an example of the semiconductor integrated circuit, but the present invention is not limited to the operational amplifier. It covers all semiconductor-related integrated circuits.

The heat generation characteristic extracting means 112 extracts heat generation characteristics for the power supply voltage from the data shown in FIG. The exothermic characteristics to be extracted are as follows.

The maximum difference ΔPmax value between the normal product (or normal) data N and the data AN with respect to the power supply voltage V ・ The total difference ΔP between the normal product (or normal) data N and the data AN with respect to the power supply voltage V Characteristics • Power supply voltage width ΔV when difference ΔP is constant • Power supply voltage V0 giving maximum difference ΔPmax value • Change ΔPV between curves N and AN with respect to power supply voltage V
(FIG. 8 shows PV1 to PV2, PV2 to PV3, PV1 to P
V3, PV11-PV21, PV21-PV31, PV
This is a change amount of the feature amount P between 11 and PV31. However, this is only an example. The change amount of the feature amount P may be taken between arbitrary times. Further, not only the amount of change but also the rate of change may be extracted. The heat generation characteristic data d equal to or larger than the heat characteristic data equal to or larger than the value of the characteristic amount Pvo on the curve AN at the time of the power supply voltage VO is stored in the characteristic database 113.

The heat generation characteristic extracting means 112 sequentially updates the following history data based on the heat generation characteristic data extracted by the apparatus of this embodiment at each aging time of the mounted circuit board used over time. The history data is stored in the characteristic database 113.

History data of the maximum difference amount ΔPmax data relating to the difference amount ΔP, the power supply voltage V, and time history data of the power supply voltage width ΔV history data of the power supply voltage V0 change amount ΔPV of the curve AN with respect to the power supply voltage V The history data of the characteristic amount Pvo on the curve AN at the time of the power supply voltage V0 The heat generation characteristic extracting means 112 makes the power supply voltage of the mounted circuit board variable, and the heat generated when the power supply voltage is applied or operated at each power supply voltage. The result (feature b) of processing the data by the thermal analysis means 111 is required.

Hereinafter, a method of varying the power supply voltage will be described.

The reason why the power supply voltage is variable and the thermal data during the operation of each voltage value is required is that the semiconductor integrated circuit has various heat generation characteristics due to different heat generation tendency with respect to the power supply voltage when the semiconductor integrated circuit is normal and when it is deteriorated. This is because it can be used as useful diagnostic information.

In order to check the state of deterioration of the mounted semiconductor integrated circuit on the mounted circuit board, it is necessary that the power supply voltage supplied to the semiconductor integrated circuit can be made variable from the outside.

(Method 1) An embodiment in which a constant voltage power supply circuit or the like is not provided in the circuit of the mounting circuit board, and a necessary voltage is directly supplied from an external power supply to the semiconductor integrated circuit on the circuit board (for example, when the semiconductor integrated circuit is DC 5 V When energized, its DC5V
Is obtained directly from an external constant voltage power supply), there is a method of manually adjusting the output value of the external constant voltage power supply. When a power supply voltage is supplied from a DC voltage generator to a semiconductor integrated circuit, there is a method of changing a voltage value by automatic remote operation by a computer or the like. Alternatively, a voltage variable device (variable resistor, in the simplest case) or the like may be inserted between the external power supply and the mounting circuit board, and may be operated manually or automatically.

(Method 2) When there is a constant voltage power supply circuit or the like in the circuit of the mounting circuit board, the output of this power supply circuit is directly
It is supplied as power for the mounted semiconductor integrated circuit. In this case, even if the external power supply is made variable, the output voltage is kept constant by the constant voltage power supply circuit of the mounting circuit board, so that the power supply voltage of the mounted semiconductor integrated circuit cannot be made variable. Therefore, the power supply circuit of the mounting circuit board is created in advance as a configuration capable of variable voltage. For example, there is a method of using a variable power supply voltage circuit or connecting a variable resistor to the output side of the constant voltage circuit. In either case, the operation is performed manually or remotely. The simplest method is to adjust it manually by using the variable operation section of the variable resistor on the circuit board. In this case, it is easy to use if the operation section of the variable resistor is provided with a scale of the variable voltage value so that the variable voltage value can be recognized.

(Processing Step 3) Characteristic Database 11
Numeral 3 stores life characteristic data such as history data of heat generation characteristics. The life characteristic data will be described. There are the following six life characteristic data. These life characteristic data are obtained from test values or field data (thermal analysis data performed during a periodic inspection of a mounted circuit board of an operating device).

The maximum difference ΔPma with respect to the life consumption rate
x data ・ Data related to difference ΔP, power supply voltage V, life consumption rate ・ Power supply voltage width ΔV data for life consumption rate ・ Power supply voltage V0 data for life consumption rate ・ Change ΔPV data for life consumption rate ・ Life consumption rate First, the maximum difference ΔPmax data with respect to the life consumption rate will be described with reference to FIGS. 14 and 15. FIG. 14 shows ΔPma
15 is a graph showing the secular change of the x value.
7 is a life graph normalized by.

The result of thermal analysis is performed at a certain period before the mounted circuit board is deteriorated on a test basis and a failure occurs. The test is, for example, a temperature / humidity stress test, a voltage stress test, or the like performed in a reliability test of an electronic component, and any test may be used as long as the test accelerates deterioration.

The figure shows the test time TE and the maximum difference ΔPma.
It is a graph of x. Each test time TE1, TE2, TE
3. Thermal analysis of the mounted circuit board that has deteriorated in TE4 is performed by the thermal analysis means 111 and 112. The maximum difference amount ΔPmax at each extracted time TE is shown.

A line connecting the plot points (or a straight line,
The curve characteristic approximation) is the time characteristic data series FPE of the maximum difference amount ΔPmax. It is also assumed that a failure has occurred in the mounted circuit board during the test time TE4. However, TE4
May be substituted at the time immediately before the occurrence of the failure or at a time point immediately before the occurrence of the failure (the point of time TE3 in FIG. 14).
In the following entire text, TE4 is described as including the case of this proviso.

The maximum difference ΔPmax at the time of occurrence of a fault is represented by ΔP
Let it be 2.

The maximum difference ΔPmax data FPL with respect to the life consumption rate is created from the test data, and the life consumption rate is calculated from the following equation.

Life consumption rate TL = each test time TE / fault occurrence time TE4. . . . . (1) By replacing the test time axis TE in FIG. 14 with the life consumption rate TL of the equation (1), the maximum difference ΔP
The max data FPL is created. The graph on the right side of FIG. 15 corresponds to this.

Next, the relationship data between the difference ΔP, the power supply voltage V, and the life consumption rate will be described with reference to FIG. FIG.
Also, as in the case of FIG. 14, it is assumed that the mounted circuit board is experimentally deteriorated and a thermal analysis is performed at a certain period until a failure occurs. The meaning of “experimental” is the same as that described with reference to FIG.
That is, it is a graph of the power supply voltage V, the difference ΔP, and the time TE. Here, the time TE is the test time TE. Time TE1
4, the thermal analysis of the mounted circuit board that has deteriorated in TE15, TE16, and TE17 is performed by the thermal analysis unit 111 and the heat generation characteristic extraction unit 112. A state where the difference ΔP with respect to the power supply voltage V at each extracted time TE is plotted is shown.

A line (or a curve approximation) connecting the plot points is a normal product (or a normal product) with respect to the power supply voltage V.
This is a characteristic data series of a difference ΔP between data N and data AN. At the test time TE17, the printed circuit board is mounted on the mounted circuit board (TE17 also has the same meaning as the proviso description of the test time TE14 in FIG.
Is assumed to have occurred. The power supply voltage V ranges from the lowest voltage required by the mounted circuit board to the maximum rated voltage.

From this test data, “Relationship data of difference ΔP, power supply voltage V, life consumption rate” for life consumption rate
Create The life consumption rate is calculated from the following equation.

Life consumption rate = each test time TE / failure occurrence time TE17. . . . . (2) By replacing the test time TE of FIG. 16 with the life consumption rate of the equation (2), “relation data of the difference ΔP, the power supply voltage V, and the life consumption rate” is obtained.

Next, the power supply voltage width ΔV data with respect to the life consumption rate will be described with reference to FIGS. In order to obtain the power supply voltage width ΔV data with respect to the life consumption rate, FIG.
FIG. 17 is created from FIG. In FIG. 16, the power supply voltage width ΔV when the difference ΔP is constant is calculated. Assuming that this constant value is ΔP3, the power supply voltage width at which the L2 line intersects with each test time TE data is calculated.

In the time TE14 data, a voltage width ΔV1 between V4 and V5. In the time TE15 data, a voltage width ΔV2 between V3 and V6. In the time TE16 data, a voltage width ΔV3 between V2 and V7. In the time TE17 data, a voltage width between V1 and V8. ΔV4. FIG. 17 is a plot of this against the test time TE.

Here, as a method of selecting ΔP3, for example, by moving the L2 line up and down with respect to the data of the failure occurrence time TE17, a difference amount ΔP of the position of the L2 line that gives the maximum possible power supply voltage width is selected (however, this selection method is used). Is not limited and can be freely selected).

This ΔP3 may be used as a deterioration judgment value. As a method of determining the deterioration determination value, for example, there is a method of determining a variation amount of ΔPmax between the curves N of a number of normal products (ΔPmax between the curves N instead of comparison with the curve AN). This variation amount may be evaluated from the width of the probability distribution of ΔPmax. ΔPmax equal to or greater than this variation amount
If so, it can be determined to be deteriorated. In FIG. 16, the variation amount is ΔP3, and the fact that ΔPmax becomes larger than this means that “ΔV> 0”.

A line (or a straight line or a curve approximation) connecting the plot points in FIG. 17 is a test time data series of the power supply voltage width ΔV. A power supply voltage width ΔV for the life consumption rate is created from the test data. The power supply voltage width ΔV data with respect to the life consumption rate is obtained by replacing the test time TE in FIG. 17 with the life consumption rate of the equation (2).

Next, the power supply voltage V0 data for the life consumption rate can be created in the same manner as the method of creating the maximum difference ΔPmax data for the life consumption rate. In other words, this description will be explained if the maximum difference ΔPmax is replaced with the power supply voltage VO in the description of “the maximum difference ΔPmax data with respect to the life consumption rate”.

The change amount ΔPV data for the life consumption rate can be created in the same manner as the method for creating the maximum difference amount ΔPmax data for the life consumption rate. In other words, the description will be described by reading the maximum difference amount ΔPmax into the change amount ΔPV in the description of “the maximum difference amount ΔPmax data with respect to the life consumption rate”. Here, the change amount ΔPV obtained from the normal data curve N
May be an initial value of the change amount ΔPV obtained from the curve AN.

Next, the feature amount Pvo data for the life consumption rate will be described. This can be created in the same manner as the method of creating the maximum difference ΔPmax data for the life consumption rate. That is, “the maximum difference ΔPma with respect to the life consumption rate
In the description of “x data”, the maximum difference ΔPmax is replaced with the feature amount Pvo data, and the description will be made. Here, the feature amount Pvo data obtained from the normal data curve N may be used as an initial value of the feature amount Pvo data obtained from the curve AN. The above is the operation of the heat generation characteristic extraction device 11.

(Processing Step 4) The diagnostic means 12 inputs the history data and the life consumption rate related data e from the characteristic database 113, and estimates whether or not the mounted circuit board has deteriorated and the life is estimated. The method of estimating the deterioration and estimating the life will be described with reference to FIG.

The judgment of the presence or absence of deterioration is made by the threshold value judgment of the history data of the heat generation characteristic. That is, in FIG. 15, when the threshold value is ΔP1, it is determined that there is deterioration when the maximum difference amount ΔPmax exceeds the threshold line L1, and it is determined that there is no deterioration when the maximum difference amount ΔPmax is equal to or less than the threshold value. Then, the left side of the graph in FIG. In this case, since the point PB at the time TR2 of the aging time TR exceeds the threshold line L1, it is determined that there is deterioration at the time TR2.

Now, how to determine threshold value L1 will be described. A number of normal mounted circuit boards of the same type are prepared, and the characteristic amount b is extracted by the thermal analysis unit 111, and a curve N in FIG. 8 is created. If there are 30 same-type mounting circuit boards, 30
The curve N is obtained. In this case, each curve N
The maximum difference ΔPmax between the two is obtained. A probability distribution (or frequency distribution) using the maximum difference amount ΔPmax as a random variable is created from the maximum difference amount ΔPmax thus obtained.
From the probability distribution, the width of the predetermined maximum difference amount ΔPmax is regarded as the variation amount. Here, “predetermined” means, for example, μ + ρ, μ + ρ × 1.22, μ + ρ × 22 (μ + ρ), 2 (μ + ρ × 1.22), 2 (μ +
ρ × 2). That is, the variation amount may be any value as long as it indicates a variation range that a normal product statistically takes. If the maximum lid amount ΔPmax is larger than this variation amount, it is statistically considered to be abnormal, so that it is determined to be deteriorated. From this idea, the amount of variation is determined by the threshold ΔP
Let it be 1. Although the above is the variation amount between normal products, this may be used as an error amount due to environmental conditions at the time of heat measurement.

The method of determining the presence or absence of deterioration from the maximum difference amount ΔPmax has been described above. Other heat generation characteristics (power supply voltage width ΔV, power supply voltage V0, change amount ΔPV, feature amount Pvo)
Also determines the presence or absence of deterioration in the same manner. However, in contrast to FIG. 13, the type in which the heat generation characteristic amount of the history data decreases with time is judged to be deteriorated if the heat generation characteristic amount becomes smaller than the threshold value.

Next, a method of diagnosing the life will be described with reference to FIG.
Assuming now that the aging time TR2, the life consumption rate TL that takes the maximum difference amount ΔPmax of the point PB is calculated from the curve FPL to TL.
I get 1. The remaining life of the mounted circuit board at this time TR2 can be calculated as follows.

Remaining life = TR2 (1 / TL1-1). . . . . . . . (3) For example, if TR2 = 10 years and the life consumption rate TL1 = 0.8, the remaining life is 2.5 years from the equation (3). Although the method of diagnosing the remaining life from the maximum difference amount ΔPmax has been described above, the remaining life can be diagnosed by the same method for other heat generation characteristics (power supply voltage width ΔV, power supply voltage V0, change amount ΔPV, feature amount Pvo). . Then, the deterioration judgment and life diagnosis result f are output to the outside.

Since the present embodiment is configured as described above, there is an effect that the heat generation characteristics of the mounted circuit board and the mounted components with respect to the power supply voltage can be extracted by the heat generation characteristics extraction device 11. This can provide useful information for diagnosis. Further, since the heat generation characteristic extracting device 11 and the diagnosis means 12 are linked, the characteristic of the heat generation tendency with respect to the power supply voltage which changes between the normal state and the deterioration state is used, and the characteristic amount of the heat generation between the normal state and the deterioration state has the maximum difference. Because the diagnosis is based on the amount of heat generated,
Highly sensitive deterioration detection and diagnosis are possible.

Hereinafter, the second embodiment will be described with reference to a functional block diagram shown in FIG.

In the mounted circuit board on which the electronic and electric components were mounted, the mounted circuit board was energized and operated at the power supply voltage V0 according to the first embodiment obtained from the heat generation tendency of the power supply voltage which was different depending on whether the mounted circuit board was normal or deteriorated. The thermal state a of the mounting surface that changes transiently in the case is input, and the thermal analysis unit 111 that extracts the characteristic amount of the thermal state that transiently changes, and the characteristic amount b extracted by the thermal analysis unit 111 are input, and the diagnostic database 14 is input. This is a deterioration diagnosis device in which a deterioration mode determining means 13 for inputting deterioration data g from the PC and determining a deterioration mode of the mounted circuit board and a diagnostic database 14 storing the deterioration data operate in conjunction with each other. The operation of this embodiment will be described with reference to FIG.

The thermal analysis means 111 sets the power supply voltage to V0,
Tests under different conditions (for example, test α, test β: test α is a rectangular wave signal input with a frequency of 200 mHz and the output is open, and test β is a rectangular wave signal input with a frequency of 50 Hz and the load current is output to the output side. (A state of energization or operation when flowing) is input. There is no restriction on the number of tests for each condition. Only one test may be used. Note that the meaning of the mounted circuit board described in the second embodiment is described in step S1.
As shown in FIG. Step S
The thermal analysis of the thermal state a input in 1 is performed. The content of the thermal analysis has already been described in the thermal analysis unit 111 of the first embodiment as shown in step S2. Deterioration mode determination means 13
Is the feature amount b (dimensional change rate,
(Dimensional steady value or temperature change rate, steady temperature). Further, the deterioration data g is input from the diagnostic database 14. This degraded data g is a diagram for explanation and is not actual data but is shown in FIG.

Here, it is assumed that the tests by conditions in which the input / output conditions are changed are test α and test β. In the table, C2 indicates a capacitor, R3 and R4 indicate resistors, and IC indicates a semiconductor integrated circuit. PT is a dimension change rate, and PS is a dimension steady value. Table K shows capacitor C2, resistors R3 and R4.
And the mounted circuit board on which the deteriorated parts such as the semiconductor integrated circuit IC are mounted are operated under the respective test conditions α and β, and the numerical values of the next-order change rate PT and the dimensional steady-state value PS extracted by the thermal analysis of the mounted circuit board are obtained. Notation.

Table L shows a capacitor C2 and a resistor R which will be described later.
3, R4, the mounted circuit board on which the deteriorated parts such as the semiconductor integrated circuit IC are mounted are operated under the respective test conditions α and β, and the result of the thermal analysis of the mounted circuit board is compared with the result of normal (or normal product). 3) shows the result of the determination of the significant difference between the feature amounts PT and PS from the mounted circuit board. In addition, the mark “○” indicates a significant difference, and the mark “X” indicates a result of no significant difference.

Tables K and L indicate that the mounted circuit board to be diagnosed was simulated beforehand for the same type of mounted circuit board as the mounted circuit board, or actually deteriorated by an environmental test or the like. This is the deterioration data created from the state at the time. In these tables, any deterioration mode may be indicated.

FIG. 20 simply shows the device names (C2, R3, R
4, IC), but for example, the semiconductor integrated circuit I
In the case of C, it may be increased depending on the deterioration characteristic. For example, in the case of an operational amplifier, the dimensional change rate PT and the dimensional steady-state value PS may be described separately for a semiconductor integrated circuit IC having a deteriorated input offset voltage, a deteriorated semiconductor integrated circuit IC having a power supply abnormality, and the like. In the case of a capacitor, a capacitor having a reduced capacitance, a capacitor having an abnormal tan delta, or the like may be used.

When the characteristic amount is a temperature change rate and a steady temperature, the deterioration mode of one mounted component is determined.
The deterioration modes of the table and the L table list the deterioration modes of “one mounted component”. Note that PS is a temperature change rate as shown in step S3, and PT is a steady temperature.

The deterioration mode determination means 13 can select and perform both the deterioration mode determination based on the numerical comparison based on the K table and the deterioration mode determination based on the significant difference determination based on the L table. Hereinafter, the deterioration mode determination method based on the L table will be described.

A significant difference judgment of the feature data b is performed. The determination of a significant difference means that a large number of normal products are analyzed by the thermal analysis means 111,
The feature amount of the mounted circuit board that has been used for a long time than the variation amount of the extracted feature amount has changed from the initial value (or the average value of the feature amounts of normal products of a large number of the same type of mounted circuit boards). In this case, it means that it is determined that there is a significant difference compared with the initial value. If there is a significant difference, it is determined that there is deterioration.

Here, when the thermal analysis means 111 has a large error in the result under environmental conditions such as ambient temperature, humidity, and air volume at the time of measurement, a significant difference may be determined based on the error width of the characteristic amount with respect to the environmental conditions. . A specific example for performing a significant difference determination is shown below. The following example is a method of performing a significant difference determination based on an error width of a feature amount with respect to an environmental condition.

Procedure 1: A normal mounted circuit board is energized and operated at different ambient temperatures, and the thermal state a is measured.

Step 2: The characteristic amount of the normal mounted circuit board is calculated by the thermal analysis means 111.

Step 3: An average value m and a standard deviation σ are calculated from each feature amount data under each ambient temperature condition.

Step 4: From the standard deviation σ, the third level value (m ±
σ × 1.22) error width {2 × (m + σ × 1.22)}
To evaluate.

Step 5: The relationship between the error width and the average value m is plotted on a graph.

Step 6: Approximate lines are obtained by least square approximation of the plot values.

Step 7: A list of estimated error widths with respect to the average value m is created from the approximate straight line.

Step 8: Calculate the absolute value of the difference between the characteristic amount b to be diagnosed and the characteristic amount in a normal state (or a normal product). If the following equation 4 is satisfied, it is determined that there is a significant difference. I do.

Difference> E (M) x = Max (yl, y2) Difference = absolute value of (y1-y2) Here, y1 is a feature amount in a normal state (or a normal product), y
2 is the feature amount b of the object to be diagnosed, and E (M) is FIG. 23 and FIG.
4, the estimated error width for the feature value M obtained from the list of 4,
Max (yl, y2) is the maximum value of y1 and y2, and M is m
If j <x <mj + 1, then M = mj + 1 and m
j and mj + 1 are the feature amounts described in the list of estimated error widths shown in FIGS.

FIG. 21 and FIG. 22 show the results obtained by calculating procedures 1 to 6 from actual data.

FIG. 21 is a graph showing the relationship between the dimension change rate PT corresponding to the average value m in the description of the procedure and the error width PTE.
A linear approximation Z1 is obtained by performing a least-squares approximation on the plot points according to the procedure 6.

FIG. 22 is a graph showing the relationship between the dimensional stationary value PS corresponding to the average value m in the explanation of the procedure and the error width PSE. A linear approximation Z2 is obtained by performing a least-squares approximation on the plot points according to the procedure 6.

FIG. 23 shows a linear approximation Z of FIGS. 21 and 22.
The estimated error width corresponding to E (M) calculated by substituting the dimension change rate PT and the dimension steady value PS in the table into the approximate expressions of 1, Z2 is shown as actual data. It should be noted that a significant difference can be determined by the above procedure even when the characteristic amount is a temperature change rate and a steady temperature. The above example can be modified as follows.

In other words, in Steps 1 and 3, if the ambient temperature is not constant but the ambient temperature is constant and “between many normal products of the same type”, the error width (that is, the variation) of the characteristic amount of the normal product is considered. This is a significant difference judgment.

In step 4, the third level value (m ± σ × 1.
22), the error width (m × σ × 1.22), the error width m + σ, and the error width 2 × (m
+ Σ) and so on. Note that this is merely an example, and the probability distribution of the feature amount may be set freely according to the purpose such as whether or not to look strictly.

Further, in the procedure 6, a straight line approximation is used, but a curve approximation may be used as a matter of course. To improve the approximation accuracy, a curve approximation may be selected as shown in step S4.

Next, the result of the significant difference determination for the feature value b is collated with the L table.

The result of the significant difference judgment of the data of the feature bl and the data of the feature b2 in the normal state (the numerical values in the table are given for explanation) in FIG. Is shown. A table b3 in FIG. 20 shows a difference value between the normal state (or a normal product, the initial value) b2 and the feature amount bl (Di in Equation 4).
reference result).

In this example, X in Expression 4 is bl
These are the values in the table. Table b4 shows the result determined from bl with reference to Equation 4 using FIG. When this determination result b4 is compared with the L table, the combination of the determination results in the column of IC is obtained as shown in step S5. Therefore, the deterioration mode determination of the mounted circuit board is IC deterioration. If the deterioration is classified in detail, it is a detailed deterioration mode judgment power. This has been described above as step S7. If there is no corresponding deterioration mode as a result of the comparison and all the results of the significant difference determination have no significant difference, the determination result can be set to “no deterioration”.

Next, a method of determining a deterioration mode based on the K table will be described with reference to FIG.

The numerical value of the characteristic amount b1 is compared with the numerical value of the K table. The identity with the numerical value in the K table may be determined in consideration of the error width. In this case, a specific example of the error width determination is as follows (illustration).

When creating the K table, deterioration data (a characteristic amount at the time of deterioration is a numerical value in the K table) for a plurality of the same type of mounted circuit boards.
To collect. Then, the amount of variation of the feature amount in the same type and the same deterioration mode is set as the error radiation.

The amount of variation in the characteristic amount due to the environmental conditions at the time of measuring the thermal state is defined as the error width.

Combination of the above two methods If there is no corresponding deterioration mode as a result of the collation, the determination result can be "no deterioration" as shown in steps S6 and S7.

[0127] Since Embodiment 2 is configured as described above, the following effects can be obtained.

Since the diagnosis target is operated at the power supply voltage V0 that gives the maximum change amount of the characteristic amount between the normal state and the deterioration state, the deterioration detection sensitivity is improved, and the diagnosis can be performed with high accuracy.

The deterioration mode is collated by the numerical comparison and judgment method of the K table of the test combination (a single test is also possible), so that the deterioration mode can be specified. Further, this method is particularly effective when the characteristic amount converges to a specific value as the deterioration proceeds. This is because it can be determined that the battery has deteriorated when the value in the K table is reached. However, this does not mean that it is effective only in this case. This is because the predetermined deterioration determination threshold value may be set to the value of the characteristic amount in the K table.

The deterioration modes are collated by the significant difference judgment method of the L table of the test combination (a single test is also possible), so that the deterioration mode can be specified. This method is particularly effective when the feature value continues to increase or decrease due to the progress of deterioration. Since it does not become a constant value, it is difficult to compare numerical values as shown in Table K. Therefore, it is determined based on a significant difference from the normal state.

Next, a third embodiment will be described.

In the first and second embodiments, when only a specific mounting component is the object of the first and second embodiments,
It is also possible to measure only the temperature of one location of a component such as an infrared optical fiber cable or a thermocouple (the measurement system is not limited and is merely an example), and the characteristic amount may be a temperature change rate or a steady temperature.

Next, a fourth embodiment will be described.

In the first and second embodiments, the present invention is applied to a mounted circuit board and its mounted parts.
On the other hand, the external surface of the electronic component not mounted on the substrate may be used. Further, an electronic circuit in a package surrounded by a package or the like may be used. For example, it is a circuit chip in a semiconductor integrated circuit package. In the case of a circuit chip, the package is opened and the thermal state of the chip inside is measured. It can be measured with a high magnification infrared temperature camera or the like.

Since the embodiment of the present invention has the above-described configuration and operation, the following effects can be obtained.

(1) By utilizing the fact that the tendency of heat generation with respect to the power supply voltage differs between a normal state and a deteriorated state, and various amounts of heat generation characteristics obtained from the maximum difference are used as deterioration diagnosis indices, deterioration detection sensitivity is high, and High-precision diagnosis is possible.

(2) Various amounts of heat generation characteristics obtained from the maximum difference between a normal state and a deteriorated state can be extracted.

(3) Since the "existence of deterioration and life estimation" of the mounted circuit board is performed using the heat generation characteristic extracted by the heat generation characteristic extraction device as a diagnostic index, the detection sensitivity and the life estimation accuracy of the presence or absence of deterioration are improved. improves.

(4) Since the life characteristic data stored in the characteristic database is used as the heat generation characteristic with respect to the life consumption rate obtained by normalizing the failure occurrence time of the mounted circuit board, the characteristic of the life estimation based on the heat generation characteristic is obtained. Can be used as a model.

(5) Deterioration is determined by determining the threshold value of the heat generation characteristic, and the heat generation characteristic in which the mounted circuit board to be diagnosed varies with the same type of product or under measurement environment conditions is represented by a probability distribution and determined from the probability distribution. Since the predetermined error width is used as a threshold value, it is possible to determine a case where the state is not statistically normal (deterioration).

(6) The remaining life of the mounted circuit board can be estimated from the heat generation characteristics.

(7) The deterioration mode can be specified.

(8) Since the method of judging a significant difference from a normal state is used, it is not necessary to judge deterioration by numerical interpretation of a feature quantity, the robustness of deterioration judgment is improved, and the result of each test for each condition is acceptable. Therefore, a highly accurate determination can be made by the combination test.

(9) A component in a mounted state can be diagnosed nondestructively.

(10) By defining the characteristic amount as a dimensional change rate or a dimensional steady value of a heat distribution or a temperature change rate or a steady temperature of a mounted component, the characteristic of a transient change in a thermal state can be quantified. Can be further improved.

[0146]

According to the present invention, the reliability of the apparatus for diagnosing circuit board deterioration can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a circuit board deterioration diagnosis apparatus showing an example of an embodiment of the present invention.

FIG. 2 is a perspective view of the mounting circuit board shown in FIG.

FIG. 3 is a perspective view of the mounting circuit board shown in FIG. 1;

FIG. 4 is an explanatory diagram showing a relationship between a temperature change rate and a steady temperature in FIG.

FIG. 5 is an explanatory diagram showing a relationship between a dimension change rate and a dimension steady value in FIG. 1;

FIG. 6 is an explanatory diagram showing fractal dimension data of a heat distribution in FIG.

FIG. 7 is an explanatory diagram showing fractal dimension data of a heat distribution in FIG. 1;

FIG. 8 is an explanatory diagram showing a tendency of a feature amount of a normal IC and a deteriorated IC in FIG. 1;

FIG. 9 is an explanatory diagram of the mounted circuit board circuit shown in FIG. 1;

FIG. 10 is an explanatory diagram showing a tendency of a temperature change rate of the IC in FIG. 1;

FIG. 11 is an explanatory diagram showing a tendency of a steady temperature of the IC in FIG. 1;

FIG. 12 is an explanatory diagram showing a tendency of a dimensional change rate of the IC in FIG. 1;

FIG. 13 is an explanatory diagram showing the tendency of the dimensional steady-state value of the IC in FIG. 1;

FIG. 14 is an explanatory diagram showing a time characteristic of the maximum difference amount ΔPmax in FIG. 1;

FIG. 15 is an explanatory diagram showing a history graph of the maximum difference amount ΔPmax in FIG. 1;

FIG. 16 is an explanatory diagram showing a relationship between a difference ΔP, a power supply voltage, and time in FIG. 1;

FIG. 17 is an explanatory diagram showing a time characteristic of a power supply voltage width ΔV in FIG. 1;

FIG. 18 is a functional block diagram showing another embodiment of the present invention.

FIG. 19 is a flowchart illustrating the operation of FIG. 18;

FIG. 20 is an explanatory diagram showing deterioration mode determination in FIG. 18;

FIG. 21 is an explanatory diagram showing a relationship between a dimension change rate and an error width in FIG. 18;

FIG. 22 is an explanatory diagram showing a relationship between a steady-state value and an error width in FIG. 18;

FIG. 23 is an explanatory diagram showing an estimated error width in FIG. 18;

FIG. 24 is an explanatory diagram showing an estimated error width in FIG. 18;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermal analysis device 11 Heat generation characteristic extraction device 12 Diagnostic means 111 Thermal analysis means 112 Thermal characteristic extraction means 113 Characteristic database

Claims (16)

[Claims] An apparatus using an electronic component or an electric component, based on the fact that the tendency of heat generation with respect to a power supply voltage differs between a normal state and a deteriorated state, using a mounting circuit board on which the electronic component or the electric part is mounted. A circuit board deterioration diagnosis device for diagnosing deterioration. 2. Thermal analysis means for inputting thermal state temporal data of a mounting surface when a mounted circuit board is energized or operated, and extracting a characteristic amount of the thermal state temporal data, and a mounted component of the mounted circuit board The power supply voltage supplied to the power supply is variable, and the characteristic amount when energized or operated at each power supply voltage value is input from the thermal analysis unit, and means for indicating the trend data of the characteristic amount with respect to the power supply voltage and a normal state. A circuit board deterioration diagnosis device, comprising: heat generation characteristic extracting means for extracting heat generation characteristics of the mounted circuit board with respect to the power supply voltage from characteristic data of the characteristic amount with respect to the power supply voltage. 3. Heat generation characteristic extraction means for extracting heat generation characteristics of the mounted circuit board with respect to the power supply voltage from tendency data of the characteristic amount with respect to the power supply voltage, and storing and extracting the heat generation characteristics extracted by the heat generation characteristic extraction means. A characteristic database for storing the history data and the life characteristic data of the heat generation characteristic, and a diagnosis unit for inputting the data stored in the characteristic database and estimating whether or not the mounted circuit board has deteriorated and estimating the life. A circuit board deterioration diagnosis apparatus characterized by the above-mentioned. 4. "Tendency data of characteristic amount with respect to power supply voltage" indicating a normal state of heat generation characteristics to be extracted and "trend data of characteristic amount with respect to power supply voltage" of a mounted circuit board used over time.
The circuit board deterioration diagnosis apparatus according to claim 2, wherein the maximum difference amount is a difference between the two. 5. In the heat generation characteristic extraction device, “the trend data of the characteristic amount with respect to the power supply voltage” indicating the normal state of the heat generation characteristic to be extracted and “the trend data of the characteristic amount with respect to the power supply voltage” of the mounted circuit board used over time. 4. The apparatus for diagnosing deterioration of a circuit board according to claim 2, wherein all difference amounts between the two are set. 6. In the heat generation characteristic extraction device, “characteristic amount trend data with respect to power supply voltage” indicating a normal state of heat generation characteristics to be extracted and “extremely small amount of trend data with respect to power supply voltage” of the mounted circuit board used over time. The circuit board deterioration diagnosis apparatus according to claim 2 or 3, wherein the power supply voltage width is set when the difference between the two is constant. 7. In the heat generation characteristic extracting device, “characteristic amount trend data for power supply voltage” indicating a normal state of the heat generation characteristic to be extracted and “characteristic amount trend data for power supply voltage” of the mounted circuit board used over time. The circuit board deterioration diagnosis apparatus according to claim 2 or 3, wherein the power supply voltage value gives a maximum difference between the power supply voltage values. 8. The heat generation characteristic extraction device according to claim 1, wherein the heat generation characteristics to be extracted indicate a normal state of “a change amount of characteristic amount tendency data with respect to a power supply voltage” and “a characteristic amount with respect to a power supply voltage of the mounted circuit board used over time”. 4. The circuit board deterioration diagnosis apparatus according to claim 2, wherein the amount of change is tendency data. 9. In the heat generation characteristic extraction device, “the trend data of the characteristic amount with respect to the power supply voltage” indicating the normal state of the heat generation characteristic to be extracted and “the trend data of the characteristic amount with respect to the power supply voltage” of the mounted circuit board used over time. The circuit board deterioration diagnosis apparatus according to claim 2, wherein a characteristic amount with respect to a power supply voltage of the aged used circuit board that gives a maximum difference amount between the two is set as “a characteristic amount with respect to a power supply voltage”. 5. 10. The heat generation characteristic with respect to the life consumption rate obtained by normalizing the life characteristic data stored in the characteristic database with the failure occurrence time of the mounted circuit board. Item 10. A circuit board deterioration diagnosis apparatus according to Item 9. 11. A method for determining whether or not deterioration has occurred in the diagnostic means by determining a threshold value of the heat generation characteristic, wherein the heat generation characteristic in which the mounted circuit board to be diagnosed varies under the same kind of product or under measurement environment conditions is represented by a probability distribution. A circuit board deterioration diagnosis apparatus, wherein a predetermined error width determined from a probability distribution is used as the threshold value. 12. The lifetime consumption rate B of a mounted circuit board used for a long time of A hours based on the lifetime characteristic by the lifetime estimation by the diagnostic means.
And estimating the remaining life of the mounted circuit board from a mathematical expression represented by remaining life = A × {(1 / B) −1}. 13. Inputting thermal state temporal data of a mounting surface when the mounting circuit board is energized or operated with a power supply voltage value obtained from a heating tendency of a power supply voltage that differs depending on whether the mounting circuit board is normal or deteriorated, Thermal analysis means for extracting the characteristic amount of the thermal state time-lapse data, and deterioration which determines the deterioration mode of the mounted circuit board by inputting the characteristic amount extracted by the thermal analysis means, comparing and comparing the characteristic amount with the deterioration data A circuit board deterioration diagnosis device, comprising: a mode determination unit. 14. Deterioration data is significantly different when a characteristic amount of a mounted circuit board having a deterioration mode is changed more than a measurement environment condition of a thermal state or a characteristic amount variation between normal products of the same type. The first degradation mode determination means that determines that there is no significant difference when there is no change, and sets the result to A, and the feature amount of the same kind as the mounted circuit board used for a long time changes more than the variation amount. A second deterioration mode determining unit that determines that there is a significant difference when the determination is made, and determines that there is no significant difference if the determination is not made, and sets the result B as the result B; To be the result,
A circuit board deterioration diagnosis device comprising: a third deterioration mode determination unit that compares the result A with the result B to determine a deterioration mode. 15. The apparatus for diagnosing deterioration of a circuit board according to claim 2, further comprising a heat generation characteristic extracting apparatus for only a specific mounted component on the mounted circuit board. . 16. A heat generation characteristic extracting device according to claim 2, wherein the characteristic amount is a dimensional change rate or a dimensional steady value of a heat distribution, or a temperature change rate of a mounted component or a steady temperature. A circuit board deterioration diagnosis device according to any one of the above.