JP5552452B2 - Heating / cooling test method and heating / cooling test apparatus - Google Patents

Description

  The present invention relates to a connection reliability test after an electronic component is mounted on a circuit board, and more particularly to a heating / cooling test method and a heating / cooling test apparatus for a connection reliability test in a solder connection portion.

  As a conventional heating / cooling test method, a test sample in which electronic components are mounted on a circuit board is placed in a large-sized constant temperature furnace, a low temperature and a high temperature holding time are specified as test conditions, and a repeated temperature cycle load is applied. A method of estimating the life of connection reliability has been used by taking out a test sample at the end of a predetermined cycle and examining changes in the conduction resistance, solder joint strength, and metal structure of the solder connection portion due to the temperature cycle. In the case of measuring the conduction resistance, a method of continuously measuring the test sample without taking out the test sample from the constant temperature furnace has been adopted.

  Usually, the temperature cycle condition is set in consideration of an acceleration coefficient, assuming the use environment of the electronic device. In general, the temperature on the low temperature side is set to -40 ° C., the temperature on the high temperature side is set to 125 ° C., and the holding time at each temperature is often set to 30 minutes, and the test period may be 1000 cycles or more. Many.

  However, in the conventional reliability test described above, the retention time at the predetermined temperature on the low temperature side and the high temperature side is often set to 30 minutes, respectively, and more than 1000 cycles are often performed as the test period. There is a problem that it takes about 3 months or more to obtain a result, and shortening the product development becomes difficult.

  In addition, in a conventional reliability test, the circuit board on which electronic components are mounted is placed in the atmosphere, which results in a change in the temperature of the entire circuit board. Since this is a local temperature change, there is a problem of testing under conditions that do not match the actual usage environment.

  In order to solve the problems in these conventional heating and cooling test methods, a Peltier element is directly attached to a circuit board, and a low temperature and a high temperature load are repeatedly applied locally to the board by controlling the current flowing through the Peltier element. In some cases, a change in conduction resistance of a test sample is measured while a temperature cycle load is applied (see, for example, Patent Document 1).

  FIG. 13 is a schematic diagram for explaining a conventional heating / cooling test method described in Patent Document 1. In FIG.

  A Peltier element 101 and a thermocouple 102 are attached to the upper surface of the electronic component 108 mounted on the circuit board 107.

  A signal corresponding to the set value is output from the temperature time control device 106 to the current control device 103, and a current set in the Peltier element 101 flows from the current control device 103. At the same time, the potential difference due to the thermoelectromotive force generated in the thermocouple 102 is measured by the temperature measuring device 104, and the temperature corresponding to the potential difference is measured and input to the temperature time control device 106.

  The temperature time control device 106 compares and monitors the measured temperature and the set temperature. After the temperature reaches the set value, the current is controlled so that the temperature becomes constant for the set holding time at that temperature. When the set holding time elapses, a signal is sent from the temperature time control device 106. The current controller 103 changes the direction of the current flowing through the Peltier element 101, changes the temperature until the other set temperature is reached, and controls until the set holding time at that temperature elapses.

  After that, the direction of the current is changed again. By repeating this series of operations, the test sample is repeatedly subjected to a temperature cycle test.

  The conduction resistance measuring device 105 is connected by a terminal to a location where the conduction resistance value of the circuit board 107 or the electronic component 108 is to be measured, and measures a change in the conduction resistance value.

JP 2002-134668 A

  However, in the above-described configuration of the conventional heating / cooling test method, it is difficult to selectively give a temperature cycle to a plurality of small electronic components mounted on a circuit board.

  That is, since the temperature cycle is given by bringing the Peltier element 101 into surface contact, it is not possible to simultaneously give a temperature cycle to the electronic components having different heights on the circuit board by one Peltier element 101.

  In addition, since the area of the Peltier element 101 is large, a temperature cycle cannot be selectively given to a plurality of small electronic components that are in surface contact.

  In addition, in order to simultaneously apply a temperature cycle to a plurality of electronic components of various shapes using the conventional heating / cooling test method, the same number of Peltier elements 101 and current control devices 103 are required, which is unrealistic. It becomes a test method.

  In consideration of the above-described conventional problems, the present invention provides a heating / cooling test method and a heating / cooling test apparatus capable of giving a temperature cycle to a plurality of electronic components mounted on a circuit board simultaneously or individually. The purpose is to provide.

In order to solve the above-described problem, the first aspect of the present invention provides:
A heating / cooling test method for evaluating a circuit board on which a plurality of electronic components are mounted via solder connections ,
A temperature raising step of raising the temperature of the electronic component by irradiating and heating a laser beam on the laser absorber placed on the electronic component;
A cooling step of cooling the electronic component by a cooling device from the surface of the circuit board on which the electronic component is not mounted;
And repeating the temperature raising step and the cooling step alternately ,
In the temperature raising step, the temperature of the electronic component measured by a temperature measuring device is compared with a heating curve of a preset temperature profile, and the temperature of the measured electronic component is read from the temperature profile. Controlling the laser beam to approach the target temperature;
In the cooling step, the temperature of the solder connection portion measured by a temperature measuring device is compared with a cooling curve of a preset temperature profile, and the temperature of the measured solder connection portion is read from the temperature profile. This is a heating and cooling test method in which the cooling device is controlled so as to approach the target temperature .
The second aspect of the present invention
A heating / cooling test method for evaluating a circuit board on which a plurality of electronic components are mounted,
A temperature raising step of raising the temperature of the electronic component by irradiating and heating a laser beam on the laser absorber placed on the electronic component;
A cooling step of cooling the electronic component by a cooling device from the surface of the circuit board on which the electronic component is not mounted;
And repeating the temperature raising step and the cooling step alternately,
In the temperature raising step, with respect to the plurality of electronic components mounted on the circuit board, the irradiation position of the laser beam is controlled by a galvanometer mirror, and the electronic component placed on any of the electronic components In the heating / cooling test method, the laser beam is irradiated to a portion of the upper surface of the laser absorber that is located immediately above the heat source of the electronic component.

The third aspect of the present invention
The lower surface of the laser absorber is the heating / cooling test method of the first or second aspect of the present invention, which is larger than the upper surface outline of the electronic component.

The fourth aspect of the present invention is
The lower surface of the laser absorber is in contact with the upper surface of the electronic component,
The first or second aspect of the present invention, wherein the laser absorber is an anisotropic thermal conductor in which a thermal conductivity in a plane direction parallel to the lower surface is larger than a thermal conductivity in a plane direction perpendicular to the lower surface. This is a heating and cooling test method.

The fifth aspect of the present invention provides
In the heating step, when irradiating the laser absorber with the laser beam, the laser beam is applied to a portion of the upper surface of the laser absorber that is located directly above the heat source of the electronic component. It is the heating-cooling test method of this invention.

The sixth aspect of the present invention provides
In the temperature raising step, with respect to the plurality of electronic components mounted on the circuit board, the irradiation position of the laser beam is controlled by a galvanometer mirror, and the electronic component placed on any of the electronic components It is the heating-cooling test method of 1st this invention irradiated to a laser absorber.

The seventh aspect of the present invention
In the heating step, the laser beam is scanned over the entire upper surface of the laser absorber by the galvanometer mirror to irradiate the laser absorber with the second or sixth book. It is the heating-cooling test method of invention.

In addition, the eighth aspect of the present invention
The cooling device is a solid cooling body,
In the cooling step, a local cooling plate installed in the solid state cooling body is brought into contact with each position corresponding to the electronic component on the surface of the circuit board on which the electronic component is not mounted. It is the heating-cooling test method of the 1st or 2nd this invention cooled by.

The ninth aspect of the present invention provides
The circuit board and the cooling device are installed in a sealed tank, and at least a part of the tank is made of a material that is transmissive to the laser beam,
In the temperature raising step, the laser absorber placed on the electronic component is irradiated with the laser beam from the outside of the tank through the portion made of the transmissive material. Or it is the heating-cooling test method of 2nd this invention.

The tenth aspect of the present invention is
It is the heating and cooling test method according to the ninth aspect of the present invention, wherein the atmosphere in the tank can be changed to any one of a low humidity atmosphere, a vacuum atmosphere, and an inert atmosphere.

The eleventh aspect of the present invention is
A heating / cooling test apparatus for evaluating a circuit board on which a plurality of electronic components are mounted via solder connection parts ,
A laser oscillator for oscillating a laser beam;
A beam shaping optical system for shaping the laser beam;
A cooling device for cooling the circuit board from a surface on which the electronic component is not mounted ;
A first temperature measuring device for measuring the temperature of the electronic component;
A second temperature measuring device for measuring the temperature of the solder connection portion;
A laser absorber placed on the upper surface of the electronic component;
A controller for repeatedly performing a temperature raising step of irradiating the upper surface of the laser absorber placed on the upper surface of the electronic component with the laser beam to raise the temperature of the electronic component, and a cooling step of cooling the electronic component; , equipped with a,
The controller is
In the temperature raising step, the temperature of the electronic component measured by the first temperature measuring device is compared with a heating curve of a preset temperature profile, and the measured temperature of the electronic component is read from the temperature profile. Controlling the laser beam to approach the target temperature
In the cooling step, the temperature of the solder connection portion measured by the second temperature measuring device is compared with a cooling curve of a preset temperature profile, and the measured temperature of the solder connection portion is read from the temperature profile. It is a heating / cooling test apparatus that controls the cooling apparatus so as to approach the target temperature at times.
The twelfth aspect of the present invention is
A heating / cooling test apparatus for evaluating a circuit board on which a plurality of electronic components are mounted,
A laser oscillator for oscillating a laser beam;
A beam shaping optical system for shaping the laser beam;
A cooling device for cooling the circuit board from a surface on which the electronic component is not mounted;
A temperature measuring device for measuring the temperature of the electronic component;
A laser absorber placed on the upper surface of the electronic component;
A controller for repeatedly performing a temperature raising step of irradiating the upper surface of the laser absorber placed on the upper surface of the electronic component with the laser beam to raise the temperature of the electronic component, and a cooling step of cooling the electronic component; ,
A galvanometer mirror capable of controlling the irradiation position of the laser beam and irradiating the laser absorber mounted on any electronic component with respect to the plurality of electronic components mounted on the circuit board; With
In the temperature raising step, the control device controls an irradiation position of the laser beam with the galvanometer mirror for the plurality of electronic components mounted on the circuit board, and controls any of the electronic components. The heating / cooling test apparatus irradiates the laser beam to a portion of the upper surface of the laser absorber placed on the upper surface of the laser absorber and located immediately above the heat source of the electronic component.

The thirteenth aspect of the present invention is
The control device controls the laser output and irradiation time of the laser beam oscillated from the laser oscillator, and controls the shape of the laser beam shaped by the beam shaping optical system . It is the heating-cooling test apparatus of this invention.

The invention related to the present invention is:
A heating / cooling test method for evaluating a circuit board on which a plurality of electronic components are mounted,
A temperature raising step of raising the temperature of the electronic component by irradiating and heating a laser beam on the laser absorber placed on the electronic component;
A cooling step of cooling the electronic component by a cooling device from the surface of the circuit board on which the electronic component is not mounted;
And repeating the temperature raising step and the cooling step alternately,
In the temperature raising step, based on the measured value of the surface temperature of the electronic component, at least the maximum temperature of the electronic component and the holding time of the maximum temperature are controlled,
The cooling step is a heating and cooling test method in which at least a minimum temperature of the electronic component and a holding time of the minimum temperature are controlled based on the measured value.

  According to the present invention, it is possible to provide a heating / cooling test method and a heating / cooling test apparatus capable of giving a temperature cycle to a plurality of electronic components mounted on a circuit board simultaneously or individually.

Configuration diagram of heating and cooling test apparatus in Embodiment 1 of the present invention Configuration diagram at the time of heating of the heating and cooling test apparatus in Embodiment 1 of the present invention The figure which shows the temperature change at the time of heating when the laser absorber is not used The figure which shows the temperature change at the time of heating when the laser absorber is not used The figure which shows the temperature change at the time of the heating in Embodiment 1 of this invention The figure which shows the temperature change at the time of the heating in Embodiment 1 of this invention Configuration diagram during cooling of the heating and cooling test apparatus in Embodiment 1 of the present invention The figure which shows the temperature change at the time of heating and cooling in Embodiment 1 of this invention Sectional block diagram of the principal part of the heating-cooling test apparatus in Embodiment 2 of this invention The block diagram at the time of the heating of the heating-cooling test apparatus in Embodiment 3 of this invention The block diagram of the heating-cooling test apparatus in Embodiment 4 of this invention The block diagram of the heating-cooling test apparatus in Embodiment 5 of this invention Schematic for explaining the conventional heating and cooling test method

  Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a heating / cooling test apparatus used for carrying out the heating / cooling test method according to Embodiment 1 of the present invention.

  The outline of the heating / cooling test apparatus 20 of Embodiment 1 is as follows. In the circuit board 5 on which a plurality of electronic components 6a to 6e are mounted, the laser absorbers 7a, 7b, 7c, and 7e are disposed on the upper surfaces of the electronic components 6a to 6e. The laser beam 3 emitted from the laser oscillator 1 is shaped by the beam shaping optical system 2, and irradiated to the laser absorbers 7a, 7b, 7c, and 7e to be heated, and from the laser absorbers 7a, 7b, 7c, and 7e. The temperature of the electronic components 6a to 6e is increased by the heat conduction, and then the irradiation of the laser beam 3 is stopped, and the solid cooling body (Peltier element 9) is applied to the circuit board 5 from the opposite side where the electronic components 6a to 6e are mounted. And the temperature cycle for cooling the electronic components 6a to 6e is repeated.

  In FIG. 1, a test sample is a circuit board 5 on which electronic components 6a, 6b, 6c, 6d, and 6e are mounted. A heating / cooling test apparatus 20 that tests the circuit board 5 is configured as follows. Has been.

  On the upper surfaces of the electronic components 6a, 6b, 6c, 6d, and 6e, laser absorbers 7a, 7b, 7c, and 7e having a size larger than the outer shape of the upper surface include the upper surfaces via the heat conductive paste. It is placed like so. For example, if the same electronic components 6c and 6d are adjacent to each other, the laser absorbers 7c placed on the surfaces of them can be combined into one piece for common use.

  The heating / cooling test apparatus 20 of the first embodiment is provided with a laser oscillator 1 for heating the electronic components 6a, 6b, 6c, 6d, and 6e, and a beam shaping optical system 2 for shaping the laser beam 3. Yes.

  Further, the laser beam 3 is deflected in order to irradiate the laser beams 7a, 7b, 7c and 7e on the electronic components 6a, 6b, 6c, 6d and 6e with the laser beams 3a, 3b, 3c and 3e. A galvanometer mirror 4 is installed on the optical axis of the laser beam 3.

  Further, below the circuit board 5, a Peltier element 9 that is a solid cooling body is installed to cool the electronic components 6a, 6b, 6c, 6d, and 6e. Furthermore, an elevator 11 having a mechanism for moving the Peltier element 9 up and down in the direction of the circuit board 5 and contacting the lower surface of the circuit board 5 is attached to the Peltier element 9.

  Further, as shown in FIG. 1, a protrusion 10 such as a connector is also provided on the circuit board 5.

  The Peltier element 9 corresponds to an example of the cooling device of the present invention.

  Next, a test method during heating in the heating / cooling test apparatus 20 according to the first embodiment will be described with reference to FIG.

  FIG. 2 shows a configuration diagram of the heating / cooling test apparatus 20 according to the first embodiment during heating. In FIG. 2, only one electronic component 6b is displayed for the electronic component for easy understanding.

  An electronic component 6b is mounted on the circuit board 5 via a solder connection portion 8b, and a laser absorber 7b having a size larger than the outer shape of the upper surface of the electronic component 6b is placed on the upper surface of the electronic component 6b with a heat conductive paste. It is put through.

  Specifically, the electronic component 6b is a BGA (ball grid array) semiconductor package whose top surface is 30 mm square, the solder connection portion 8b is formed of several tens of solder balls, and the laser absorber 7b. The size of each is 35 mm square and 2 mm thick.

  Further, a temperature measuring device 12a for measuring the surface temperature is attached to the electronic component 6b, and a temperature measuring device 12b for measuring the surface temperature is attached to the solder connection portion 8b. As the temperature measuring devices 12a and 12b, there are contact-type thermocouples and non-contact-type temperature measuring devices using heat radiation light.

  The Peltier element 9 below the circuit board 5 is not in contact with the circuit board 5 when the electronic component 6b is heated.

  Further, the control device 13 of the heating / cooling test apparatus 20 of the first embodiment includes a temperature measurement function of the electronic component 6b and the solder connection portion 8b, an output control function of the laser oscillator 1, and a beam shape control of the beam shaping optical system 2. A function, a temperature control function of the Peltier element 9, a lift control function of the elevator 11 of the Peltier element 9, and a temperature cycle control function.

  First, the laser beam 3 oscillated from the laser oscillator 1 is shaped into a predetermined laser beam shape by the beam shaping optical system 2.

  Next, the shaped laser beam 3 is deflected by the galvanometer mirror 4, and the laser beam 3b is irradiated to the laser absorber 7b and heated. The temperature of the electronic component 6b rises due to heat conduction from the heated laser absorber 7b, and the temperature at that time is measured by the temperature measuring device 12a. Further, heat is transferred from the heated electronic component 6b to the circuit board 5 through the solder connection portion 8b, and the temperature of the solder connection portion 8b is measured by the temperature measuring device 12b.

  The control device 13 compares the temperature of the electronic component 6b measured by the temperature measuring device 12a with the heating curve of the temperature profile set in advance in the control device 13, and at the time of heating, the temperature detected by the temperature measuring device 12a is An instruction for output is given to the laser oscillator 1 so as to approach the target temperature at each time read from the temperature profile, and after reaching a predetermined maximum temperature, the maximum temperature is maintained for a time set in the temperature profile. Give instructions.

  Thus, the control device 13 controls the heating in accordance with the heating curve of the temperature profile, and the control for maintaining the maximum temperature for the time set in the temperature profile corresponds to an example of the temperature raising step of the present invention.

  The laser absorber 7b of the first embodiment is a material that absorbs the thermal energy of the laser beam 3b and is not damaged by the thermal energy of the laser beam 3b, for example, a metal material such as iron, copper, or aluminum. It is configured.

  The electronic component 6b is generally resin-molded. When the resin mold portion of the electronic component 6b is directly irradiated with the laser beam 3b, the thermal energy of the laser beam 3b is absorbed by the resin mold surface portion of the electronic component 6b, and the resin mold Only the surface portion suddenly increases in temperature. For example, when the surface temperature is 160 ° C. or higher, it may be burnt.

  3 and 4 show the temperature change of the electronic component 6b and the solder connection portion 8b when the resin mold surface of the electronic component 6b is directly irradiated and heated without using the laser absorber 7b. FIG. FIG. 3 shows each temperature change when the laser output is 20 W, and FIG. 4 shows each temperature change when the laser output is 18 W. 3 and 4, T1 indicates a temperature change curve of the electronic component 6b, and T2 indicates a temperature change curve of the solder connection portion 8b.

  For example, when the laser beam 3b is directly irradiated onto the surface of the resin mold of the electronic component 6b with a laser output of 20 W and heated, the temperature changes as shown in FIG. That is, 5 minutes after the laser irradiation, the temperature T1 of the electronic component 6b reaches 160 ° C., and the resin mold portion of the electronic component 6b is burnt. At this time, the temperature T2 of the solder connection portion 8b is 80 ° C., and does not reach the required temperature of 105 ° C.

  Conversely, when the output of the laser beam 3 is lowered to 18 W so as not to burn the resin mold surface portion, the temperature T1 of the electronic component 6b becomes 150 ° C. or lower as shown in FIG. 4, but the temperature of the solder connection portion 8b. T2 is only up to 70 ° C. even after 15 minutes from saturation, and has not reached the required temperature of 105 ° C. In this saturated state, since the energy input to the electronic component 6b and the heat radiation energy from the electronic component 6b and the circuit board 5 are balanced, the temperature of the solder connection portion 8b does not rise any more.

  Here, in the first embodiment, in order to raise the temperature of the electronic component 6b to the required temperature, when the output of the laser beam 3 is increased and thermal energy is input to the electronic component 6b, the laser beam 3b is applied to the electronic component 6b. This problem is solved by mounting a laser absorber 7b that is not damaged by thermal energy.

  FIG. 5 is a diagram showing temperature changes of the electronic component 6b and the solder connection portion 8b during heating in the heating / cooling test apparatus 20 of the first embodiment using the laser absorber 7b.

  For example, as a more specific example of using the laser absorber 7b, when the electronic component 6b is irradiated to the laser absorber 7b with a laser output of 30 W and a laser beam diameter of 30 mm, the temperature changes as shown in FIG. Go. 5 minutes after the laser irradiation, the temperature T1 of the electronic component 6b reaches 150 ° C. at which the electronic component 6b does not burn, the temperature T2 of the solder connection portion 8b reaches 105 ° C., and the temperature is maintained for 10 minutes thereafter.

  In each figure, arrows indicating laser beams 3, 3a, 3b, 3c, and 3e indicate positions through which the optical axis passes. In this case, since the laser beam 3b having a laser beam diameter of φ30 mm is irradiated to a substantially central position of the 35 mm square laser absorber 7b placed on the 30 mm square upper surface of the electronic component 6b, the entire upper surface of the electronic component 6b is irradiated. In addition, the outer part of the laser absorber 7b is not irradiated and only the electronic component 6b is selectively heated.

  On the other hand, if the laser output is increased in order to increase the temperature of the solder connection portion 8b in a shorter time, the temperature of the electronic component 6b becomes 160 ° C. or more, and the resin mold portion is burnt.

  In order to raise the temperature of the solder connection portion 8b in a short time, as the laser absorber 7b, the thermal conductivity in the plane direction parallel to the contact surface with the electronic component 6b is in the direction perpendicular to the contact surface with the electronic component 6b. An anisotropic thermal conductor having a higher thermal conductivity, such as a graphite material, may be used.

  When the laser absorber 7b having such anisotropic thermal conductor characteristics is irradiated with the laser beam 3b, heat is quickly and uniformly applied to the laser irradiation side surface of the laser absorber 7b parallel to the contact surface of the electronic component 6b. On the other hand, since heat is not immediately transmitted in the thickness direction, thermal energy is accumulated in the laser absorber 7b. Thereafter, this thermal energy is transmitted to the surface side of the laser absorber 7b that is in contact with the electronic component 6b. Furthermore, the heat conduction paste between the laser absorber 7b and the electronic component 6b is efficiently transmitted to the side of the electronic component 6b in contact with the laser absorber 7b, and the temperature of the solder connection portion 8b of the electronic component 6b is increased. Go up.

  Therefore, even if the laser output is further increased, heat energy is accumulated in the laser absorber 7b, so that the temperature of the solder connection portion 8b can be increased without scorching the resin mold portion of the electronic component 6b.

  FIG. 6 is a diagram illustrating temperature changes of the electronic component 6b and the solder connection portion 8b during heating in the heating / cooling test apparatus 20 according to the first embodiment using an anisotropic thermal conductor as the laser absorber 7b. .

  As a specific example, when the laser absorber 7b is irradiated to the electronic component 6b with a laser output of 45 W and a laser beam diameter of 30 mm, the temperature changes as shown in FIG. After 2 minutes of laser irradiation, the temperature T1 of the electronic component 6b reaches 150 ° C. at which the electronic component 6b does not burn, the temperature T2 of the solder connection portion 8b reaches 105 ° C., and then the temperature is maintained for 5.5 minutes. Yes.

  Next, a test method at the time of cooling in the heating / cooling test apparatus 20 of the first embodiment will be described with reference to FIG.

  FIG. 7 shows a configuration diagram of the heating / cooling test apparatus 20 according to the first embodiment during cooling. In FIG. 7, only one electronic component 6b is displayed as an electronic component for easy understanding.

During cooling, the control device 13 stops the laser beam 3 oscillated from the laser oscillator 1 and controls the elevator 11 of the Peltier element 9 to raise the Peltier element 9 and bring it into contact with the bottom surface of the circuit board 5. At the same time, the control unit 13, the temperature of the solder connection portion 8b measured at a temperature measuring device 12b, against a cooling curve of the preset temperature profile to the controller 13, the temperature measuring device 12 b at the time of cooling After the energization to the Peltier element 9 is controlled so that the detected temperature approaches the target temperature at the time of reading from the temperature profile and reaches a predetermined minimum temperature, the minimum temperature is set in the temperature profile. The energization to the Peltier element 9 is controlled so as to maintain only the time.

  In this way, the control device 13 performs cooling control in accordance with the cooling curve of the temperature profile and maintains the minimum temperature for the time set in the temperature profile corresponds to an example of the cooling step of the present invention.

  FIG. 8 is a diagram showing temperature changes of the electronic component 6b and the solder connection portion 8b during heating and cooling in the heating and cooling test apparatus 20 of the first embodiment.

  For example, as shown in FIG. 8, when the temperature of the Peltier element 9 is set to −45 ° C. during cooling, laser irradiation is stopped after 7.5 minutes of laser heating, and the Peltier element 9 is brought into contact with the circuit board 5 to 2 The temperature T1 of the electronic component 6b reached −40 ° C. at the position of 9.5 minutes after the lapse of minutes. It can be seen that the time required for heating and cooling can be shortened to about ¼ compared to the time required for each of the conventional large test tanks of about 30 minutes.

  Then, the control device 13 performs a predetermined number of heating / cooling tests by controlling the temperature raising step and the cooling step so as to be alternately performed a predetermined number of times. The process of repeatedly performing the temperature raising step and the cooling step is an example of the repeating step of the present invention.

  In the above description, the cooling step is performed after the heating step. However, either the heating step or the cooling step may be performed at the beginning of the repetition step, and the heating step is performed at the end of the repetition step. Control may be performed to perform either the cooling step or the cooling step.

  The above description in the first embodiment is an example in the case where there is only one electronic component 6b. However, by moving the galvanometer mirror 4 and changing the irradiation direction of the laser beam 3, the circuit board 5 in FIG. The laser absorbers 7a, 7b, 7c, and 7e on the arbitrary electronic components 6a, 6b, 6c, 6d, and 6e can be individually irradiated with the laser beams 3a, 3b, 3c, and 3e. In addition, for the arbitrary electronic components 6a, 6b, 6c, 6d, and 6e, an optimal laser condition is selected by the control device 13, laser output control is performed on the laser oscillator 1, and the beam shaping optical system 2 is selected. By shaping the laser beam 3, the temperature profiles of the arbitrary electronic components 6a, 6b, 6c, 6d, and 6e can be individually controlled.

  In the conventional heating / cooling test, in order to perform the heating / cooling test of the plurality of electronic components 6a, 6b, 6c, 6d, 6e, for example, first, the heating / cooling test of a predetermined cycle is performed on the electronic component 6a, Next, similarly, the heating / cooling test for all the electronic components 6a, 6b, 6c, 6d, and 6e is completed by performing the heating / cooling test of a predetermined cycle for the electronic components 6b, 6c, 6d, and 6e.

  On the other hand, in the case of the heating / cooling test apparatus 20 of the first embodiment, the galvanometer mirror 4 is scanned at high speed, and the laser absorbers 7a, 7b on the plurality of electronic components 6a, 6b, 6c, 6d, 6e. , 7c, and 7e are repeatedly irradiated with laser beams 3a, 3b, 3c, and 3e in order, so that the temperature of the plurality of electronic components 6a, 6b, 6c, 6d, and 6e can be raised simultaneously.

  For example, the galvanometer mirror 4 is scanned and positioned at a high speed of 1 Hz, and the laser absorbers 7a, 7b, 7c, and 7e on the plurality of electronic components 6a, 6b, 6c, 6d, and 6e are sequentially arranged. The laser beams 3a, 3b, 3c, and 3e are irradiated for only 1 second. In the configuration of the first embodiment, there are four laser absorbers 7a, 7b, 7c, and 7e that are laser irradiation targets. Therefore, for each laser absorber 7a, 7b, 7c, and 7e, every 4 seconds. The laser beam 3 is irradiated for 1 second, and this is repeated continuously.

  For example, by increasing the laser output by a factor of 4 with respect to the laser output required to raise the temperature of one electronic component, the laser beams 3a, 3b, 3c and 3e can be irradiated every 4 seconds for only 1 second. Each of the laser absorbers 7a, 7b, 7c, and 7e can be heated with a temperature profile substantially similar to that during continuous irradiation. Thereafter, the electronic components 6a, 6b, 6c, 6d, and 6e can be cooled at once by the Peltier element 9.

  Therefore, in the configuration of the first embodiment, since the heating / cooling test can be simultaneously performed on the five electronic components 6a, 6b, 6c, 6d, and 6e, the heating is performed in 1/5 time as compared with the conventional case. A cooling test can be performed.

  Therefore, if the heating / cooling test method according to the first embodiment is used, N identical electronic components are mounted on the circuit board 5, and the N electronic components are simultaneously heated under the same laser irradiation conditions. By cooling, N increase confirmation under the same heating and cooling conditions can be performed in one test.

  Even if the same electronic component is mounted, each electronic component can be heated simultaneously under different laser irradiation conditions, so that a heating / cooling test under different heating conditions can be performed in one test.

(Embodiment 2)
FIG. 9 is a cross-sectional configuration diagram of a main part of the heating and cooling test apparatus according to the second embodiment of the present invention. The same reference numerals are used for the same components as in FIG.

  FIG. 9 shows the laser irradiation position of the laser beam 3b on the laser absorber 7b on the electronic component 6b.

  In the first embodiment, as shown in FIG. 2, the laser beam 3b is irradiated so that the optical axis comes to substantially the center of the laser absorber 7b on the electronic component 6b.

  However, in an electronic component 6b formed of a certain BGA semiconductor package, an IC chip as a heat source 14 may be arranged in the interior of the electronic component 6b so as to be shifted from the central portion in the layout. In such an electronic component 6b, the laser absorber 7b is irradiated with the laser beam 3b so that the optical axis is positioned immediately above the heat source 14, and the electronic component 6b is heated. It is possible to reproduce the heat generation state close to, enabling a more reliable heating / cooling test.

  Therefore, the control device 13 of the second embodiment controls the galvanometer mirror 4 so that the laser beam 3b is irradiated to the position of the laser absorber 7b that is directly above the heat source 14 of the electronic component 6b. .

(Embodiment 3)
FIG. 10 is a configuration diagram of the heating / cooling test apparatus 21 according to Embodiment 3 of the present invention during heating. The same reference numerals are used for the same components as in FIG.

  As shown in FIG. 10, the control device 13 of the third embodiment controls the galvanometer mirror 4 so that the laser absorber 7b on the electronic component 6b scans the entire surface of the laser beam 3b.

  In the configurations of the first and second embodiments, the laser beam 3b is fixed and irradiated at a predetermined position of the laser absorber 7b on the electronic component 6b, and therefore, with respect to the laser beam diameter of the laser beam 3b to be irradiated. When the area of the electronic component 6b is relatively large, the laser absorber 7b may not be heated completely and uniformly over the entire surface.

  For example, when the electronic component 6b is 30 mm square and the laser absorber 7b is 35 mm square and the laser beam 3b having a laser beam diameter of φ10 mm is irradiated, the vicinity of the center of the upper surface of the electronic component 6b is heated, but the outside of the upper surface The part is not heated enough.

  On the other hand, in the heating / cooling test apparatus 21 according to the third embodiment, a laser beam 3b is scanned over the entire surface of the laser absorber 7b on the electronic component 6b by using the galvano mirror 4, so that an electronic component having a large area is obtained. Even 6b can be heated substantially uniformly. Furthermore, since the scanning area of the galvanometer mirror 4 can be set easily and freely, it is possible to deal with electronic parts and laser absorbers of various shapes and sizes.

  Note that when the irradiation position of the laser beam 3b is scanned over the entire surface of the laser absorber 7b, it is preferable to scan in a range where the laser beam 3b does not protrude outside the laser absorber 7b. This is because if the irradiation range of the laser beam 3b protrudes outside the laser absorber 7b, the parts and the substrate surface that are outside the laser absorber 7b and do not need to be heated are heated.

(Embodiment 4)
FIG. 11 is a configuration diagram of the heating / cooling test apparatus 22 according to the fourth embodiment of the present invention. The same reference numerals are used for the same components as in FIG.

  FIG. 11 shows that the electronic components 6a, 6b, 6c, 6d, and 6e are selectively cooled.

  In the first embodiment, as shown in FIG. 1, the Peltier element 9 is entirely in contact with the lower surface of the circuit board 5 for cooling.

  However, the lower surface of the actual circuit board 5 may have protrusions 10a and 10b such as other electronic components and connectors. In this case, the Peltier element 9 is in full contact with the lower surface of the circuit board 5. I can't let you.

  Therefore, in the heating / cooling test apparatus 22 of the fourth embodiment, the upper surface of the Peltier element 9 (on the surface in contact with the circuit board 5) is smaller than the size of the outer surface of the electronic components 6a, 6b, 6c, 6d to be cooled. The local cooling plates 15a, 15b, 15c made of, for example, copper / aluminum, which are large and have good thermal conductivity, are attached. By doing so, the protrusions 10a, 10b on the lower surface of the circuit board 5 are avoided. At the same time, the electronic components 6a, 6b, 6c and 6d can be selectively cooled.

  In the configuration of the fourth embodiment shown in FIG. 11, since the electronic component 6e is not desired to be cooled, no local cooling plate is attached to the position of the Peltier element 9 below the electronic component 6e.

(Embodiment 5)
FIG. 12 is a configuration diagram of the heating / cooling test apparatus 23 according to the fifth embodiment of the present invention. The same reference numerals are used for the same components as in FIG.

  As shown in FIG. 12, the heating / cooling test apparatus 23 according to the fifth embodiment is placed in a test tank 16 whose main part can be sealed, and the laser beams 3a, 3b, 3c, 3e The laser absorbers 7a, 7b, 7c and 7e are irradiated through a transmission window 17 attached to a part of the outer periphery of the laser.

  Further, the test tank 16 is provided with a replacement device 18 that can evacuate the inside of the test tank 16 or replace it with another gas.

  The test tank 16 corresponds to an example of the sealed tank of the present invention, and the transmission window 17 corresponds to an example of a portion made of a material that is transmissive to the laser beam of the present invention.

  In the heating / cooling test apparatuses of Embodiments 1 to 4, the electronic components 6a, 6b, 6c, 6d, and 6e are cooled in the atmosphere using the Peltier element 9, so the cooling temperature is lowered to −45 ° C. As a result, the Peltier device 9 may condense and the cooling performance to the circuit board 5 and the electronic components 6a, 6b, 6c, 6d, and 6e may be reduced.

  On the other hand, in the heating / cooling test apparatus of the fifth embodiment, the replacement apparatus 18 makes the inside of the test tank 16 a low humidity atmosphere, a vacuum atmosphere, or an inert gas atmosphere such as argon gas. Condensation can be prevented and cooling performance can be prevented from lowering.

  In each embodiment, the Peltier element 9 is used as the cooling device. However, other cooling devices may be used. For example, a configuration in which a gaseous refrigerant is allowed to pass through the lower surface of the circuit board 5 to be cooled may be employed.

  As described above, by using the heating / cooling test method of the present invention, an actual destruction phenomenon is caused by causing a heat conduction phenomenon similar to self-heating to a plurality of electronic components having different shapes. In addition to providing such a thermal process temperature cycle, the reliability test can be performed in a short time. In addition, a temperature cycle can be simultaneously applied to a plurality of electronic components having various shapes.

  The heating / cooling test method and the heating / cooling test apparatus according to the present invention have an effect that a plurality of electronic components mounted on a circuit board can be simultaneously or individually given a temperature cycle, and are subjected to a reliability test. It can be applied not only to surface treatments such as heat treatment that imparts a temperature cycle.

DESCRIPTION OF SYMBOLS 1 Laser oscillator 2 Beam shaping optical system 3, 3a, 3b, 3c, 3e Laser beam 4 Galvanometer mirror 5 Circuit board 6a, 6b, 6c, 6d, 6e Electronic component 7a, 7b, 7c, 7e Laser absorber 8a, 8b Solder Connection part 9 Peltier element 10, 10a, 10b Protrusion 11 Elevator 12a, 12b Temperature measuring device 13 Control device 14 Heat source 15a, 15b, 15c Local cooling plate 16 Test tank 17 Transmission window 18 Replacement device 20, 21, 22, 23 Heating / cooling test apparatus 101 Peltier element 102 Thermocouple 103 Current control apparatus 104 Temperature measurement apparatus 105 Conduction resistance measurement apparatus 106 Temperature time control apparatus 107 Circuit board 108 Electronic component

Claims (13)

A heating / cooling test method for evaluating a circuit board on which a plurality of electronic components are mounted via solder connections ,
A temperature raising step of raising the temperature of the electronic component by irradiating and heating a laser beam on the laser absorber placed on the electronic component;
A cooling step of cooling the electronic component by a cooling device from the surface of the circuit board on which the electronic component is not mounted;
And repeating the temperature raising step and the cooling step alternately ,
In the temperature raising step, the temperature of the electronic component measured by a temperature measuring device is compared with a heating curve of a preset temperature profile, and the temperature of the measured electronic component is read from the temperature profile. Controlling the laser beam to approach the target temperature;
In the cooling step, the temperature of the solder connection portion measured by a temperature measuring device is compared with a cooling curve of a preset temperature profile, and the temperature of the measured solder connection portion is read from the temperature profile. A heating / cooling test method , wherein the cooling device is controlled so as to approach a target temperature . A heating / cooling test method for evaluating a circuit board on which a plurality of electronic components are mounted,
A temperature raising step of raising the temperature of the electronic component by irradiating and heating a laser beam on the laser absorber placed on the electronic component;
A cooling step of cooling the electronic component by a cooling device from the surface of the circuit board on which the electronic component is not mounted;
And repeating the temperature raising step and the cooling step alternately ,
In the temperature raising step, with respect to the plurality of electronic components mounted on the circuit board, the irradiation position of the laser beam is controlled by a galvanometer mirror, and the electronic component placed on any of the electronic components A heating / cooling test method in which the laser beam is irradiated to a portion of the upper surface of the laser absorber that is located immediately above the heat source of the electronic component . The lower surface of the laser absorber, the greater the upper surface contour of the electronic components, heating and cooling the test method according to claim 1 or 2. The lower surface of the laser absorber is in contact with the upper surface of the electronic component,
The said laser absorber is an anisotropic thermal conductor whose thermal conductivity of the surface direction parallel to the said lower surface is larger than the thermal conductivity of the surface direction perpendicular | vertical to the said lower surface. Heating / cooling test method.   In the temperature raising step, when irradiating the laser absorber with the laser beam, the laser beam is applied to a portion of the upper surface of the laser absorber that is located immediately above the heat source of the electronic component. The heating / cooling test method according to 1.   In the temperature raising step, with respect to the plurality of electronic components mounted on the circuit board, the irradiation position of the laser beam is controlled by a galvanometer mirror, and the electronic component placed on any of the electronic components The heating / cooling test method according to claim 1, wherein the laser absorber is irradiated. 7. The laser beam irradiation is performed according to claim 2 , wherein, in the temperature raising step, the laser beam is scanned by the galvanometer mirror over the entire upper surface of the laser absorber and irradiated with the laser beam. Heating / cooling test method. The cooling device is a solid cooling body,
In the cooling step, a local cooling plate installed in the solid state cooling body is brought into contact with each position corresponding to the electronic component on the surface of the circuit board on which the electronic component is not mounted. cooled by heating the cooling test method according to claim 1 or 2. The circuit board and the cooling device are installed in a sealed tank, and at least a part of the tank is made of a material that is transmissive to the laser beam,
The laser beam irradiation is performed on the laser absorber placed on the electronic component from the outside of the tank through the portion made of the transmissive material in the temperature raising step. The heating / cooling test method according to 1 or 2 .   The heating / cooling test method according to claim 9, wherein the atmosphere in the tank can be changed to any one of a low humidity atmosphere, a vacuum atmosphere, and an inert atmosphere. A heating / cooling test apparatus for evaluating a circuit board on which a plurality of electronic components are mounted via solder connection parts ,
A laser oscillator for oscillating a laser beam;
A beam shaping optical system for shaping the laser beam;
A cooling device for cooling the circuit board from a surface on which the electronic component is not mounted ;
A first temperature measuring device for measuring the temperature of the electronic component;
A second temperature measuring device for measuring the temperature of the solder connection portion;
A laser absorber placed on the upper surface of the electronic component;
A controller for repeatedly performing a temperature raising step of irradiating the upper surface of the laser absorber placed on the upper surface of the electronic component with the laser beam to raise the temperature of the electronic component, and a cooling step of cooling the electronic component; , equipped with a,
The controller is
In the temperature raising step, the temperature of the electronic component measured by the first temperature measuring device is compared with a heating curve of a preset temperature profile, and the measured temperature of the electronic component is read from the temperature profile. Controlling the laser beam to approach the target temperature
In the cooling step, the temperature of the solder connection portion measured by the second temperature measuring device is compared with a cooling curve of a preset temperature profile, and the measured temperature of the solder connection portion is read from the temperature profile. A heating / cooling test apparatus for controlling the cooling apparatus so as to approach the target temperature at times . A heating / cooling test apparatus for evaluating a circuit board on which a plurality of electronic components are mounted,
A laser oscillator for oscillating a laser beam;
A beam shaping optical system for shaping the laser beam;
A cooling device for cooling the circuit board from a surface on which the electronic component is not mounted ;
A temperature measuring device for measuring the temperature of the electronic component;
A laser absorber placed on the upper surface of the electronic component;
A controller for repeatedly performing a temperature raising step of irradiating the upper surface of the laser absorber placed on the upper surface of the electronic component with the laser beam to raise the temperature of the electronic component, and a cooling step of cooling the electronic component; ,
A galvanometer mirror capable of controlling the irradiation position of the laser beam and irradiating the laser absorber mounted on any electronic component with respect to the plurality of electronic components mounted on the circuit board; With
In the temperature raising step , the control device controls an irradiation position of the laser beam with the galvanometer mirror for the plurality of electronic components mounted on the circuit board, and controls any of the electronic components. A heating / cooling test apparatus for irradiating a portion of the upper surface of the laser absorber placed on the upper surface of the laser absorber directly above the heat source of the electronic component with the laser beam . Wherein the control device controls the laser output and irradiation time of the laser beam oscillated from the laser oscillator, and controls the laser beam shape is shaped by the beam shaping optical system, according to claim 11 or 12 The heating / cooling test apparatus according to 1.

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