JP2015137889A - Testing method of control board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a testing method of a control board, which can reduce outflow of a defect to the market and can reduce the cost brought about by the defect.SOLUTION: When a control board constituting a control circuit of a power device is tested in a manufacturing process of an intelligent power module having the control board mounted thereon, a function test of measuring electric characteristics of the control board in a state where the temperature of the control board is a first temperature, to detect abnormality is first performed. Next, a function test of measuring electric characteristics of the control board in a state where the temperature of the control board is a second temperature different from the first temperature, to detect abnormality is performed. Next, a temperature sweep test of monitoring variation in electric characteristics of the control board during sweep from the first temperature to the second temperature of the control board to detect abnormality is performed.

Description

  The present invention relates to a function test of a control board in the manufacturing process of an intelligent power module (IPM) equipped with a control board (printed wiring board) constituting a control circuit of a power device.

  The function test of the control board is performed at a low temperature, a normal temperature, and a high temperature, respectively (for example, see Patent Document 1). For example, a low temperature test is first performed at a temperature of -40 ° C. Next, it waits until predetermined time passes in a preheating stage (25 degreeC dry air environment) in order to prevent dew condensation. Next, a room temperature test is performed at 25 ° C. Finally, a high temperature test is performed at 100 ° C. Thereafter, in order to cool the control substrate temperature to 25 ° C., which is room temperature, the control board waits until a predetermined time elapses in a standby stage (in room temperature). After these test steps, the process proceeds to the next step.

JP 2010-071809 A

  Since the control board temperature changes continuously under the actual usage environment of the IPM, the conventional test method cannot cover abnormality detection at all points within the allowable temperature range, and many electronic components mounted on the control board cannot be detected. As a result of the accumulation of temperature-dependent electrical characteristics, abnormalities that occur only at a certain intermediate temperature cannot be detected. For this reason, there was a problem that the outflow of defects to the market increased and the cost increased due to these defects.

  The present invention has been made to solve the above-described problems, and its purpose is to reduce the outflow of defects to the market and to control the costs caused by the defects. A method for testing a substrate is obtained.

  A test method for a control board according to the present invention is a test method for a control board in a manufacturing process of an intelligent power module having a control board constituting a control circuit of a power device, wherein the temperature of the control board is a first value. A step of performing a function test for detecting an abnormality by measuring an electrical characteristic of the control board at a temperature, and measuring an electrical characteristic of the control board at a second temperature at which the temperature of the control board is different from the first temperature And performing a function test for detecting an abnormality, and detecting an abnormality by monitoring a change in electrical characteristics of the control board while the temperature of the control board is swept from the first temperature to the second temperature. And a step of performing a temperature sweep test.

  In the present invention, while the temperature of the control board is swept from the first temperature to the second temperature, a temperature sweep test is performed to monitor a change in the electrical characteristics of the control board and detect an abnormality. Thereby, it is possible to detect an abnormality that occurs only at a specific intermediate temperature between the first temperature and the second temperature. For this reason, the outflow of defects to the market can be reduced, and the cost generated due to the defects can be reduced.

It is a flowchart of the test method of the control board which concerns on Embodiment 1 of this invention. It is a figure which shows the signal output with respect to temperature. It is a figure which shows the temperature gradient of the control board at the time of the temperature sweep test which concerns on Embodiment 1 of this invention. It is a figure which shows the temperature gradient of a control board at the time of setting delay time in Embodiment 1 of this invention. It is sectional drawing which shows the air blower which concerns on Embodiment 1 of this invention, and a top view which shows a ventilation baffle plate. It is a flowchart of the test method of the control board which concerns on Embodiment 2 of this invention. It is a figure which shows the temperature gradient of the control board at the time of the temperature sweep test which concerns on Embodiment 2 of this invention. It is a figure which shows the temperature gradient of a control board at the time of setting delay time in Embodiment 2 of this invention.

  A control board test method according to an embodiment of the present invention will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repeated description may be omitted.

Embodiment 1 FIG.
FIG. 1 is a flowchart of a control board test method according to Embodiment 1 of the present invention. This test method is a function test of the control board in the manufacturing process of the intelligent power module (IPM) equipped with the control board (printed wiring board) constituting the control circuit of the power device.

  First, the control substrate is passed through a low temperature bath, and the substrate temperature is lowered to −40 ° C. (low temperature) (step S1). Next, a function test (low temperature test) is performed to detect an abnormality by measuring the electrical characteristics of the control board when the temperature of the control board is −40 ° C. (low temperature) (step S2). Next, the control board is transported to the preheat stage to prevent condensation (step S3). The control board is blown with 25 ° C. dry air (step S4) and waits until a predetermined time elapses (step S5).

  Next, a function test (normal temperature test) is performed to detect an abnormality by measuring electrical characteristics of the control substrate when the temperature of the control substrate is 25 ° C. (normal temperature) (step S6). Next, the control substrate is passed through a high temperature bath to raise the substrate temperature to 100 ° C. (high temperature) (step S7). Next, a function test (high temperature test) is performed to detect an abnormality by measuring the electrical characteristics of the control board when the temperature of the control board is 100 ° C. (step S8). Next, a temperature sweep test for monitoring changes in the electrical characteristics of the control board and detecting abnormalities is repeated until 25 ° C. of room temperature is reached, while blowing cool air of 25 ° C. to cool the control board (step S9). (Steps S10 and S11). After these test steps, the process proceeds to the next step.

  In this embodiment, while the temperature of the control board is swept from 100 ° C. (high temperature) to 25 ° C. (room temperature), a temperature sweep test is performed to monitor the change in the electrical characteristics of the control board and detect an abnormality. Thereby, the abnormality which generate | occur | produces only in the certain intermediate temperature between 100 degreeC and 25 degreeC is detectable. For this reason, the outflow of defects to the market can be reduced, and the cost generated due to the defects can be reduced.

  FIG. 2 is a diagram showing a signal output with respect to temperature. A broken line graph is a comparative example, and tests are performed only at temperature points corresponding to dots of −40 ° C. (low temperature), 25 ° C. (normal temperature), and 100 ° C. (high temperature). For this reason, for example, if an abnormality is observed in the signal output only at specific temperatures (here, two locations of 75 ° C. and −10 ° C.) as shown in the thin solid line graph, the abnormality cannot be detected in the comparative example. On the other hand, since the functional test is repeatedly performed from a high temperature of 100 ° C. to a normal temperature of 25 ° C. as in the present embodiment, an output abnormality that occurs only at 75 ° C. in FIG. 2 can be detected.

  FIG. 3 is a diagram showing a temperature gradient of the control board during the temperature sweep test according to Embodiment 1 of the present invention. A thin line shows the case where cold air is blown with a constant air volume. A thick line indicates a case where the air volume is controlled so as to keep the temperature gradient of the control board constant. In this way, when cooling is performed with a constant air volume, the temperature gradient of the control board is not necessarily constant. Therefore, the air volume is controlled by monitoring the temperature of the control board so as to keep the temperature gradient of the control board constant. Thereby, the ratio of the test data sampling with respect to the temperature change within the temperature sweep range can be made constant. Conversely, the sampling density can be increased by a specific temperature range. That is, it is possible to construct a test method according to the purpose of inspection and the temperature characteristics of the control board.

  FIG. 4 is a diagram showing a temperature gradient of the control board when the delay time is set in the first embodiment of the present invention. When the stage has only a cooling function and no heating function, it is preferable to maintain a state close to the temperature of the high temperature test at the start of the temperature sweep test. However, since the temperature of the control board has already started to decrease at the start of the temperature sweep test, a temperature region in which the test cannot be performed occurs. Therefore, it is preferable to delay the start timing of blowing by a certain time with respect to the start timing of the temperature sweep test. As a result, the temperature can be maintained close to the temperature of the high temperature test at the start of the temperature sweep test, so that the temperature range where the test cannot be performed can be kept to a minimum.

  FIG. 5: is sectional drawing which shows the air blower which concerns on Embodiment 1 of this invention, and a top view which shows an airflow baffle plate. The stage 1 holds an IPM control board 2 as a test sample. In the temperature sweep test, the wind generated by the electric blower (fan) 3 is blown to the control board 2 through the ventilation hole 5 of the ventilation rectifying plate 4 and the ventilation hole 7 of the ventilation rectifying plate 6. Here, the blower opening of the electric blower (fan) 3 is arranged to face the center of the control board 2. The ventilation holes 5 of the ventilation rectifying plate 4 and the ventilation holes 7 of the ventilation rectifying plate 6 are alternately arranged. Thereby, the air sent to the control board 2 becomes a laminar flow, and the in-plane uniformity of the temperature of the control board 2 is improved. Therefore, the detection accuracy with respect to the test temperature can be improved.

Embodiment 2. FIG.
FIG. 6 is a flowchart of the control board test method according to the second embodiment of the present invention. First, the control substrate is passed through a low temperature bath, and the substrate temperature is lowered to −40 ° C. (low temperature) (step S1). Next, a function test (low temperature test) is performed to detect an abnormality by measuring the electrical characteristics of the control board when the temperature of the control board is −40 ° C. (low temperature) (step S2). Next, the control board is transported to the preheat stage to prevent condensation (step S3). While blowing dry air at 25 ° C. to the control board (step S4), a temperature sweep test for monitoring the change in the electrical characteristics of the control board and detecting an abnormality is repeated until reaching 25 ° C. of the room temperature (steps S12 and S13). .

  Next, a function test (normal temperature test) is performed to detect an abnormality by measuring the electrical characteristics of the control substrate when the temperature of the control substrate is 25 ° C. (normal temperature) (step S6). Next, the control substrate is passed through a high temperature bath to raise the substrate temperature to 100 ° C. (high temperature) (step S7). Next, a function test (high temperature test) is performed to detect an abnormality by measuring the electrical characteristics of the control board when the temperature of the control board is 100 ° C. (step S8). Next, in order to cool the control board, cold air of 25 ° C. is blown (step S9), and the process waits until a predetermined time has elapsed (step S14). After these test steps, the process proceeds to the next step.

  In the present embodiment, while the temperature of the control board is swept from −40 ° C. (low temperature) to 25 ° C. (normal temperature), a temperature sweep test is performed to monitor the change in the electrical characteristics of the control board and detect an abnormality. Thereby, the abnormality which generate | occur | produces only in the certain intermediate temperature between -40 degreeC and 25 degreeC is detectable. For example, an output abnormality that occurs only at −10 ° C. in FIG. 2 can be detected. For this reason, the outflow of defects to the market can be reduced, and the cost generated due to the defects can be reduced.

  FIG. 7 is a diagram showing a temperature gradient of the control board during the temperature sweep test according to Embodiment 2 of the present invention. A thin line shows the case where dry air is blown with a constant air volume. A thick line indicates a case where the air volume is controlled so as to keep the temperature gradient of the control board constant. When the air is blown at a constant air volume as described above, the temperature gradient of the control board is not necessarily constant. Therefore, the air volume is controlled by monitoring the temperature of the control board so as to keep the temperature gradient of the control board constant. Thereby, the ratio of the test data sampling with respect to the temperature change within the temperature sweep range can be made constant. Conversely, the sampling density can be increased by a specific temperature range. That is, it is possible to construct a test method according to the purpose of inspection and the temperature characteristics of the control board.

  FIG. 8 is a diagram showing a temperature gradient of the control board when the delay time is set in the second embodiment of the present invention. When the stage has only a heating function and no cooling function, it is preferable to maintain a temperature close to the temperature of the low temperature test at the start of the temperature sweep test. However, since the temperature of the control board has already started to rise at the start of the temperature sweep test, a temperature region in which the test cannot be performed occurs. Therefore, it is preferable to delay the start timing of blowing by a certain time with respect to the start timing of the temperature sweep test. As a result, since the temperature can be maintained close to the temperature of the low temperature test at the start of the temperature sweep test, the temperature range where the test cannot be performed can be kept to a minimum.

  Also in this embodiment, by using the air blower of FIG. 5 in the temperature sweep test, the air blown to the control board 2 becomes a laminar flow, and the in-plane uniformity of the temperature of the control board 2 is improved. Therefore, the detection accuracy with respect to the test temperature can be improved.

2 Control board, 3 Electric blower, 4, 6 Ventilation plate, 5, 7 Ventilation hole

Claims (4)

A test method of the control board in the manufacturing process of an intelligent power module equipped with a control board constituting a control circuit of a power device,
Performing a function test for detecting an abnormality by measuring electrical characteristics of the control board at a first temperature of the control board; and
Performing a function test for detecting an abnormality by measuring electrical characteristics of the control board at a second temperature at which the temperature of the control board is different from the first temperature;
A step of performing a temperature sweep test for monitoring a change in electrical characteristics of the control board and detecting an abnormality while the temperature of the control board is swept from the first temperature to the second temperature. A method for testing a semiconductor device.   The air flow is controlled by monitoring the temperature of the control board so as to keep the temperature gradient of the control board constant while blowing air to the control board when performing the temperature sweep test. The test method of the control board as described.   3. The test method for a control board according to claim 2, wherein the start timing of blowing is delayed for a predetermined time with respect to the start timing of the temperature sweep test. In the temperature sweep test, the wind generated by the electric blower is blown to the control board through the ventilation hole of the first ventilation rectifying plate and the ventilation hole of the second ventilation rectifying plate,
The air blower opening of the electric blower is disposed opposite the center of the control board,
4. The control board test method according to claim 1, wherein the ventilation holes of the first ventilation rectifying plate and the ventilation holes of the second ventilation rectifying plate are alternately arranged. 5.

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