SU1448313A1 - Method of checking the quality of assembly of module with solid-state power device - Google Patents

Abstract

The invention can be used for mass express control of modules with power semiconductor devices (PC) of tablet execution. The purpose of the invention is to increase the reliability of control of the module by assessing the quality of the thermal contacts of the assembly of the module. The method is implemented by heating the power semi-, conductor 1-1 with a current pulse from generator 2, measuring the voltage drop across its structure before the pulse, after the pulse and with a delay after the heating pulse. For this purpose, a voltage drop measuring unit 8, a counting unit 9 and a programmable control unit 12 are provided. The build quality is determined by the criterion, which is the ratio of the voltage drop difference on the forward shifted PP at the end of the heating current pulse and the initial voltage drop on the forward shifted transition. As the difference of the voltage drops on the forward shifted transition upon the end of the pulse heating current and at the end of a specified delay interval. 3 il. (L 4 & 4 00 CO 00

Description

The invention relates to power semiconductor technology and can be used for mass express control of modules with power semiconductor devices at the factory or in the field of operation.

The purpose of the invention is to increase the reliability of control due to the evaluation of the thermal contacts of the assembly of the module.

FIG. I shows a diagram of the stand of mass control of modules on 1FIG. 2 is a control control chart; in fig. 3 - diagrams of the change in the semiconductor temperature: the structure in the process of control.

The method is implemented in the stand circuit (Fig. 1), to which the monitored module 1 is connected, i.e., the power semiconductor 1.1 itself with 1.2 and 1.3 chillers, as well as the clamping device and the down-conductors. The stand itself contains a stabilized source of heating current 2 connected to the semiconductor I.1 through the contactor 3 and the quick disconnect power terminals 4 and 5.

In addition, to the semiconductor 1.1 through the low-current terminals 6 and 7 of the sub-switches, the unit 8 measures the voltage drop across the semiconductor structure 1.1. The composition of this unit includes a measuring current source (about 0.5-0.8 A) and a digital voltmeter connected in accordance with a typical circuit. The output of block 8 is connected to the counting unit 9.

A stabilized single-vibrator 10 is provided for controlling the contactor 3. The input of block 8 is connected to the output of an OR 11 logic element, one of the inputs of which is connected to input 12.1 of the program control unit 12, output 12.2 of which is connected to input 10. of the single-oscillator 10, outputs 12.3, 12.4 - with the inputs of the element VDI I1, output 12.5 - with the input of the block 9.

The method is implemented as follows.

After installing module 1 on the stand and attaching the terminals 4-1, the unit 12 is started up, which automatically turns on the blocks 8, 9 and the Stand single-oscillator 10 in accordance with the diagram of FIG. 2, namely at the moment t on the output 12.1 generate a pulse that passes through the ele

ment 11 and starts measurement block 8, which fixes the drop in voltage d U on structure 1A at current 1, the iUo value is digitally transmitted to block 9; at time t, output 12.2 generates a pulse that triggers a 1 V one-shot and for the time of the Year turns on contactor 3, providing heating of the semiconductor 1 A with current If. source 2f immediately after the end of the heating pulse and disconnecting the contactor 3, block 12 at time t, generates a pulse at output 12.3, which through element 11 starts block 8, measures the voltage drop, and the next impulse unit 12 generates at output 12.4 at time t. after a fixed period of time (after the end of the pulse G; according to this pulse, block 8 performs a measurement of the voltage drop across the structure, the last pulse is generated at time t, the counting unit 9 starts, which calculates the value

E I - AC °

 & and, - UU,

(one)

This value is an indicator of the quality of the assembly of module 1. It is compared with the tolerance value Eddp at E.E.n module is rejected, and

AOP

Consider having been tested.

To justify the representativeness of the magnitude E in FIG. 3, the process of heating the structure with a current pulse IP and its subsequent development is considered. FIG. 3a shows a pulse T ,, with duration C, and FIG. 3 - the process of changing the temperature 0 of the structure under the action of this pulse and after it for good and bad modules. In a good semiconductor module, it has a low thermal resistance to the case-cooler and good thermal contacts inside the semiconductor device. Therefore, due to the good heat transfer in the cooler, the structure is heated to a temperature which is lower than that of a bad module, which due to high thermal resistance, the structure is heated to & Mo (COP).

When cooled, i.e. at t t, there is an inverse relationship: a good modulus is faster, and a bad one is slower, so ((, in 2 –P). Therefore, if in t

3J4483I3

the ratio of temperature changes during heating and heating, we obtain a value that is more sensitive to the quality of the assembly of the module than each of the considered values separately.

The proposed method allows to do without stabilizing the power in the structure. Only current stabilization 1 is needed, which is realized by much simpler means than power stabilization.

FIG. 3E) shows as an example the process of heating and cooling the valve in with a high voltage drop on the structure and the valve AND with a low voltage drop. The process is shown for the case of identical thermal resistances of module 1. Valve B heats up faster and, after switching off, its temperature also drops faster. The exponents of the host structure have the same time constant, the initial values of

spread of values. In order to increase the sensitivity of E to the temperature resistance of the moduli

blows the correct choice of the parameters G and t, as well as the amplitude 1. The parameters o should be equal to the constant heating time — semiconductor cooling 1.1 (without coolers 1.2,

10 1.3). Current 1 should be such as to ensure the maximum allowable heating of the structure during the time of the traffic flow factor. This ensures fast and efficient monitoring of modules by crit.

15 ryu e,

Claims (1)

Invention Formula 20 and only differ And w neither mi & u u u 25 The method of controlling the quality of the assembly of a module with a power semiconductor device, which consists in measuring the voltage drop at the forward shifted semiconductor device, passes a heating current pulse through the semiconductor device, measuring the voltage drop at the straight shifted semiconductor device transition at the end of the current pulse, according to the data obtained, an informative parameter is calculated and 30 is compared with a valid value, characterized in that, in order to increase the reliability of control over t quality assessment thermal contact module assembly, vscher- thus provided sta- 35 alive semiconductor obes1 thermal performance, i.e. the same build quality of modules B and H 1li Awol liu - AUe l luU - Nurr (2) measured over a predetermined time interval after the end of the heating current pulse, the voltage drop is measured on the forward-displaced This method is independent of the electrical parameters of the structure, i.e. regardless of D U. It is also important to note that the expression (1) gives one and. the same result when substituting into it the values of the voltage drop on the structure or the corresponding values of the temperature of the structure. The reason is that the coefficient K of the temperature sensitivity of the voltage iU is stable over a wide range of temperatures for a constant measuring current of 1 const, i.e. iU Kb, and K ≈ 2 mV / deg, (3), so that when substituting (3) into (1), the coefficient K decreases. Thus, this method, implemented using the formula (1), pochtochennym within a specified time interval after the end of the heating current pulse, measure the voltage drop across the shifted 40 transition of a semiconductor device at the end of a predetermined lag time interval, an informative parameter is determined with respect to the difference in the value of the voltage drop across the right 45 shifted transition of the semiconductor device at the end of the heating current pulse and the initial value of the voltage drop at the forward shifted transition to the difference value 50 SRI voltage drop on a straight-shifted junction at the end of a heating current pulse and at the end of a specified lag time interval and by the result of the comparison poluvol a receive criterion E for quality control in the assembly module 5 chennogo The relative informative parameter Su in relative (dimensionless) form, the D t of an assembly wherein the modulation with Cu value E depends little on sexually-semiconductor device. spread of values. In order to increase the sensitivity of E to the temperature resistance of the moduli blows the correct choice of the parameters G and t, as well as the amplitude 1. The parameters o should be equal to the constant heating time — semiconductor cooling 1.1 (without coolers 1.2, 1.3). Current 1 should be such as to ensure the maximum allowable heating of the structure during the time of the traffic flow factor. This ensures fast and efficient monitoring of modules by crit. Ria E, Invention Formula 20 30 35 25 30 35 measured over a predetermined time interval after the end of the heating current pulse, the voltage drop is measured on the forward-displaced 0 junction semiconductor device; at the end of a predetermined lag time interval, an informative parameter is determined with respect to the difference of the value of the voltage drop across the straight 5 shifted junction of the semiconductor device at the end of the heating current pulse and the initial value of the voltage drop across the forward shifted voltage drop direct shifting at the end of the heating current pulse and at the end of the specified delay time interval and by the result of the comparison of the obtained informative parameter Su- D t of an assembly of modules with sexually-Cu semiconductor device. tft fo FIG. g totjiz Fi.e