JP2002014065A - Method and apparatus for measuring heating amount of electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the heating amount of electronic components, in a state in which the components are mounted on a printed board. SOLUTION: In the method for measuring the heating amount of electronic components by providing an apparatus 3 for measuring heating having a Peltier element on an element 2 to be measured mounted on a printed board 1 and controlling the current of the Peltier element, the thermal resistance between the element 2 and the Peltier element is dynamically changed, a thermal resistance Rjb between a junction of the element and the lower surface from a heating amount Pc of the upper surface side of the element measured by a temperature-measuring instrument 4 before and after the change of the thermal resistance is found from a thermal resistance Rjc between the junction, of the element and an upper surface clarified by a manufactures test, and the heating amount of the element P (=Tc-Tb+(Rjb+Rjc)×Pc/Rjb) is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the heat generation of electronic parts for measuring the heat generation and thermal characteristics of individual elements on a printed circuit board actually mounted on a product level.

[0002]

2. Description of the Related Art Conventionally, the measurement of heat generation of an electronic component on a printed board is performed by measuring the current and voltage of a main circuit of an element 2 to be measured provided on a printed circuit board 1 as shown in FIG. Measure directly using meter V, or measure probe 1
A method is used in which the power consumption is obtained by indirectly measuring with the measuring instrument 10 having 0a, and the calorific value of the element to be measured is measured.

[0003]

However, elements mounted on a printed board mounted in an electronic device are:
Since the amount of heat generation is estimated assuming the operation state of each element, it is very difficult to grasp the amount of heat generation in the state of actual operation.

[0004] In particular, in the indirect measurement in which the current of the above-mentioned element is measured with a probe, it is not possible to measure accurately with a small current.

Further, BGA (Ball Grid Ar)
ray), it is more difficult to directly measure the current value of the circuit due to the lack of leads on the element, and it is practically impossible to measure the heating value of the element. . Further, even when the voltage and current values are measured using a jig, it is difficult to measure the heat radiation characteristics at the same time because the actual use state is not obtained. In the case of an element operating at a higher speed, there is a problem that a predetermined operation is not performed even when the element is attached to a jig.

In a semiconductor such as an LSI, the junction temperature Tj needs to be lower than an allowable temperature. However, since the junction temperature Tj cannot be directly measured in the element actually used, conventionally, the ambient temperature Tj of the element is conventionally used.
a or the surface temperature Tc of the element is measured to measure the junction temperature Tj. Since the thermal resistance between the temperatures is measured in advance by the LSI maker, the thermal resistance is calculated from the heat value P of the element set separately using the following basic formula.

[0007] Element ambient allowable temperature Ta (max) = Tj
(Max) · α1−P × Rja Here, Rja is a thermal resistance, and α1: a derating rate.

Element surface allowable temperature Tc (max) = Tj
(Max) · α2−P × Rjc where Rjc is a thermal resistance and α2 is a derating rate.

This is shown in FIG. However, as described above, the heat value P is an estimated value and the junction temperature T
j could not be determined exactly.

At present, a thermal model of an element on a printed board is generally considered as shown in FIG. However, it was extremely difficult to measure individual thermal resistance except at the laboratory level of LSI manufacturers.

In FIGS. 2 and 3, Ta is the element ambient temperature, Tc element surface temperature, Tb is element lower surface (element printed board side) temperature, Tj is element junction temperature, Rca and Rba are element element temperatures. Rja, Rjc, Rjb are the junction thermal resistances of the junction and periphery of the element, the surface and the lower surface, P is the heat generation of the element, Pc and Pb are the upper and lower surfaces of the element. The calorific value. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to simultaneously mount the calorific value and thermal characteristics of elements on a printed board, which were conventionally difficult to measure, on a printed board of an actual product level. It is an object of the present invention to provide a method and an apparatus for measuring the calorific value of an electronic component which can be measured in a state where the electronic component is measured.

[0012]

According to a first method of measuring the amount of heat generated by an electronic component of the present invention, a cooling element whose cooling amount is changed by an electric current is provided on an element to be measured mounted on a printed circuit board. By controlling the current of the target element, the thermal resistance between the upper surface of the element to be measured and the cooling element is dynamically changed, and the calorific value of the upper surface and the upper and lower temperatures of the element to be measured before and after the change in the thermal resistance are measured. It is characterized in that the calorific value of the measurement target element is obtained by calculation from the measured temperature and heat absorption amount and the thermal resistance value between the junction and the upper surface of the measurement target element, which is clarified by a manufacturer test.

[0013] A first electronic component calorific value measuring device for carrying out the first method comprises: a calorific value measuring device for measuring an upper surface calorific value of an element to be measured having a cooling element whose cooling amount changes with an electric current; A temperature measuring device having respective sensors for detecting the upper surface temperature and the lower surface temperature of the target element, and the heat generation amount measured by the heat measuring device and the temperature measuring device, and the junction of the measuring target element clarified by each temperature and a maker test And a calculating means for calculating a calorific value of the element to be measured from a thermal resistance value between the upper surface and the upper surface.

According to a second method of measuring the calorific value of an electronic component according to the present invention, a calorific value measuring section made of a heat conductive member is provided on an element to be measured mounted on a printed circuit board, and cooling is provided on the calorific value measuring section. Provide a device, change the performance of this cooling device, measure the temperature of the upper and lower surfaces of the element to be measured and the temperature of the upper surface of the heat generation measurement unit before and after the change of the performance, by the measured temperature and manufacturer test The method is characterized in that the calorific value of the device to be measured is calculated from the thermal resistance value between the junction and the upper surface of the device to be measured that is known.

An electronic component calorific value measuring apparatus for carrying out the second method includes a calorific value measuring section composed of a heat conducting member mounted on an element to be measured mounted on a printed circuit board; A cooling device provided on the top, a temperature measuring device having each sensor for detecting the upper surface temperature and the lower surface temperature of the element to be measured, and the upper surface temperature of the heat generation measuring section, and the respective temperatures measured by the temperature measuring device. An arithmetic unit for calculating a heat generation amount of the measurement target element from a junction between the measurement target element and a thermal resistance value between the upper surface, which is clarified in a manufacturer test.

The cooling device may be constituted by a Peltier element and a fan or a heat sink and a fan.

In addition, a heat transfer portion whose periphery is covered with a heat insulating material and has a heat measurement portion mounting hole at the center of the lower surface is integrally provided below the cooling device, and the heat transfer portion of the cooling device heat transfer portion is provided above the heat generation measurement portion. It is preferable that a heat transfer piece having a projection that fits into the mounting hole is provided integrally, and the heat generation measuring section is detachable from the cooling device.

In this case, it is preferable to prepare a plurality of heat measurement units having different sizes so that they can be exchanged according to the size of the element to be measured.

[0019]

FIG. 1 shows an electronic component calorific value measuring apparatus according to a first embodiment. In the figure, 1 is a printed board at the product level, 2 is an element to be measured on the printed board, 3 is an exothermic measuring device using a cooler such as a Peltier element, 4 is an upper surface, lower surface temperature Tc of the element 2,
A temperature measuring device having a sensor for detecting Tb, and A is an ammeter for measuring the Peltier element current of the heat measuring device 3.

The upper and lower temperatures Tb and Tc of the element 2 can be measured by a temperature measuring device 4, and the upper surface of the element 2 and the heat measuring device 3
The heat generation amount Pc of the upper surface of the element 2 which greatly changes the thermal resistance Rca between the coolers can be measured by the heat measurement device 3. By measuring the measurable temperatures Tc and Tb and the heat value Pc, the thermal resistance Rjb between the junction and the lower surface of the element 2 and the heat value P of the element 2 are calculated. When the thermal resistance Rca is changed, the temperature Tc changes as shown in FIG.

Hereinafter, a method of calculating Rjb and P will be described.

The relational expression of heat of the thermal model in the mounting state of FIG. 3 is generally as follows.

1 / Rja = 1 / (Rjc + Rca) + 1 / (Rjb + Rba) (1) P = Pc + Pb where (Rjc + Rca + Rjb + R
If ba = R, Pc = (Rjb + Rba) / R, Pb = (Rjc + Rc)
a) / R 2. The relational expression of each temperature Tc, Tj, Tb, Ta is as follows: Tj = Rjc × Pc + Tc, Tc = Rja × Pc + Ta, Tb = Tj−Rjb × Pb (2)

This model can also be represented by the following equation.

Tc = Tb + Rjb × Pb-Rjc × Pc Since Pb = P−Pc, Tc = Tb + Rjb × (P−Pc) −Rjc × Pc = Tb + Rjb × P− (Rjb + Rjc) × Pc (3) However, Rjc is usually disclosed in terms of data, but Rjb is unknown. Therefore, even if Pc is calculated in this state, the overall heat generation amount P is unknown.

The thermal resistance (corresponding to Rca in FIG. 3) of the exothermic measuring device 3 connected to the upper surface of the element 2 is changed (for example, by controlling the current value of the Peltier element, the thermal resistance Rca).
Is dynamically changed), and the above contents are measured with Rca in two or more states. As a result, the temperature of each part changes, but Rjb and P can be directly obtained by the following equation based on the temperature difference.

1) Rca is large; RcaI (each value I) 2) Rca is small; RcaII (each value II) Since Rjc and Rjb do not change, I and II are the same. In each of the states I and II, the above equation (3) becomes as follows.

TcI = TbI + Rjb × P− (Rjb + Rjc) × PcI (4) TcII = TbII + Rjb × P− (Rjb + Rjc) × PcII (5) Equation (5) is as follows.

TcI-TcII = (TbI-TbII)
− (Rjb + Rjc) × (PcI−PcII) By transforming this, (Rjb + Rjc) × (PcI−PcII) = (TbI
−TbII) − (TcI−TcII) (Rjb + Rjc) = ｛(TbI−TbII) − (Tc
I−TcII)｝ / (PcI−PcII) Therefore, Rjb = {(TbI−TbII) − (TcI−
TcII)｝ / (PcI-PcII) -Rjc (6)

By transforming equation (3), P = {Tc−Tb + (Rjb + Rjc) × Pc} / Rjb (7) In the equations (6) and (7), measurement can be performed with all components except for Rjc mounted on a printed board at the same level as the product. Rjc is evident in basic manufacturer tests. Therefore, Rjb and Pc can be easily calculated at the same time, and P can be obtained by calculation.

Although a simple model having only one element has been described, the present measuring method is effective even when other components are mounted on a printed board.

Further, since Rba can be arbitrarily changed without affecting the measurement result, simultaneously changing Rba and Rca is effective for improving accuracy and reducing measurement time.

Second Embodiment FIG. 5 shows an electronic component heat generation measuring apparatus according to a second embodiment. In the figure, 1 is a printed board at the product level, 2 is an element to be measured, 4 is a temperature measuring instrument having a sensor for detecting each part temperature Tx, Tc, Tb, 5 is a heat generation measuring section provided on the upper surface of the element 2, Reference numeral 6 denotes a cooling device including a Peltier element or a fan provided on the upper surface of the heat measurement unit 5, and A denotes an ammeter for detecting a current flowing through the cooling device 6.

The temperatures Tc and Tb of the upper and lower surfaces of the element 2 and the temperature Tx of the upper surface of the heat measurement section 5 can be measured by the temperature measuring device 4. The temperatures Tc, Tx, and Tb are measured, and the calorific value Pc of the upper surface of the element and the thermal resistance Rjb between the element junction and the lower surface are calculated to calculate the calorific value P of the element.

FIG. 6 shows a thermal resistance model according to the second embodiment. In the drawing, Tx indicates the temperature of the upper surface of the heat measurement part, and Rxa indicates the thermal resistance between the upper surface temperature Tx of the heat measurement part and the cooling device temperature Ta.

In the second embodiment, the performance of the cooling device 6 connected above the heat measurement unit 5 is changed. (Equivalent to the thermal resistance Rxa in FIG. 6). For example, 1) dynamically changing the thermal resistance Rxa by controlling the current value of the Peltier element, or 2) changing the airflow of the fan. As a result, the above contents are measured with Rxa in two or more states. . As a result, the temperature of each part changes, but Rjb and P can be directly obtained by the following equation based on the temperature difference.

1) Rxa is large; RxaI (each value I) 2) Rxa is small; RxaII (each value II) Since Rjc and Rjb do not change, I and II are the same. In each of the states I and II, the above equation (3) becomes as follows.

TcI = TbI + Rjb × P− (Rjb + Rjc) × PcI (4) TcII = TbII + Rjb × P− (Rjb + Rjc) × PcII (5) Equation (5) is as follows.

TcI-TcII = (TbI-TbII)
− (Rjb + Rjc) × (PcI−PcII) By transforming this, (Rjb + Rjc) × (PcI−PcII) = (TbI
−TbII) − (TcI−TcII) ∴ (Rjb + Rjc) = ｛(TbI−TbII) − (T
cI-TcII)｝ / (PcI-PcII)

[0040]

(Equation 1)

By transforming the above equation (3), P = ｛T
c−Tb + (Rjb + Rjc) × Pc｝ / Rjb ...
(7).

[0042]

(Equation 2)

In equations (6 ') and (7'), Tc, Tb,
Tx can be measured while all are mounted on a printed circuit board of the same level as the product. Rcx can be determined because a known material is used. Rjc is evident in basic manufacturer tests. Therefore, Rjb and Pc can be easily calculated at the same time, and P can be obtained by calculation.

Although this model has been described as a simple model having only one element, the present measuring method is effective even when another product is mounted on a printed board and heat is generated.

Further, even if Rba is arbitrarily changed, the above measurement result is not affected. Therefore, simultaneously changing Rba and Rxa is effective for improving accuracy and reducing measurement time.

Embodiment 1 FIG. 7 shows an embodiment of the calorific value measuring apparatus. Cooling device 6
And a fan 8 is provided thereon. The heat generation measuring device 7 includes a temperature measuring unit 7a, a DC power supply E for supplying a current to the Peltier element of the cooling device 6, and a calculating unit 7b for calculating the above equations (6 ') and (7').

The lower part of the cooling device 6 is connected to a heat transfer part 6a connected to a Peltier element. A pin hole 6b for connecting the measuring head 9 is provided at the center of the lower surface of the heat transfer section 6a, and a heat insulating material 6c is provided around the heat transfer section 6a.

The measuring head 9 is provided with a pin hole 6b of the heat transfer portion 6a at the center of the upper surface of the main body 9a having the heat generation measuring portion 5 on the lower surface.
The pin 9b is fitted to the heat transfer portion 6a and is detachable from the lower end of the heat transfer portion 6a. Insulation material 9c around the measuring head 9
Is given. Note that a temperature measurement sensor can be inserted between the main body 9a of the measurement head 9 and the heat generation measurement section 5.

The measuring head 9 is prepared in several types, large, medium and small, and can be replaced according to the size of the element to be measured and the amount of heat generated.

The measurement head 9 is attached to the heat transfer section 6a of the cooling device 6, the heat generation measurement section 5 is brought into contact with the upper surface of the element to be measured, and a current is supplied to the Peltier element to cool the electric heating section 6a.
a, Tb and Tc are measured. The calculation unit 4b uses a known Rjb
Using the measured Ta, Tb, and Tc, the equations (6 ') and (7') are calculated.

Embodiment 2 FIG. 8 shows an embodiment in which a heat sink is used as a cooling device of the calorific value measuring device. A number of heat sinks 6 'are erected on a base 6d as a cooling device 6, and a fan 8 is provided thereon. A heat transfer section 6a is integrally provided below the base 6d of the heat sink 6 'in the same manner as in the first embodiment.
A measuring head 9 having a heat generation measuring unit 5 is detachably provided at a lower end of the measuring head 9.

A medium is sealed in the heat sink 6 ', and the medium absorbs heat from the heat transfer section 6a and is vaporized.
When the heat is dissipated to the fan 8 side, it liquefies and absorbs the heat from the heat transfer section again, thereby cooling the heat transfer section 6a.

Then, the measuring head 9 is attached to the electric heating section 6a cooled by the heat sink 6 ',
Is applied to the upper surface of the element to be measured, and the temperatures Ta, Tb, Tc
Is calculated, and the calculation unit 7b calculates the expressions (6 ′) and (7 ′).

[0054]

Since the present invention is configured as described above, the calorific value and the thermal characteristics of the elements on the printed board, which have been difficult to measure in the past, can be measured at the same time when mounted on the printed board of the actual product level. Can be measured.

As in the first and second embodiments, a heat generation measuring device and a cooling device can be arbitrarily selected, and a Peltier element and a heat sink (with each fan) are optionally provided in the cooling portion according to the heat generation amount of the element to be measured. Can be selected. In addition, the heat generation measuring section can perform high-precision and efficient measurement by selecting the size and the thermal resistance according to the heat generation amount and the size of the element to be measured.

Since the heat measurement unit measures Pc, the cooling unit only needs to be able to change the performance of the cooling unit by changing the speed of the fan, the voltage of the Peltier element, etc., and does not require an expensive controller or sensor.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a calorific value measuring device according to a first embodiment.

FIG. 2 is an explanatory diagram of a thermal resistance of a measurement target element.

FIG. 3 is a thermal resistance model of an element to be measured.

FIG. 4 is a diagram showing a relationship between a temperature of a measurement target element and a calorific value;

FIG. 5 is a configuration explanatory view of a calorific value measuring device according to a second embodiment.

FIG. 6 is a thermal resistance model of an element to be measured.

FIG. 7 is a configuration explanatory diagram of a calorific value measuring device according to Example 1 of Embodiment 2;

FIG. 8 is a configuration explanatory diagram of a calorific value measuring device according to a second example of the second embodiment.

FIG. 9 is an explanatory diagram of a calorific value measuring method according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Printed board of a product level 2 ... Device to be measured 3 ... Heat generation measuring device using Peltier device etc. 4 ... Temperature measuring device 4 ', 4 "... Heat generation measuring device 5 ... Heat generation measuring unit 6 ... Cooling device such as Peltier device 6 ': heat sink 6a: heat transfer section 7: measuring head 8: fan

Claims (8)

[Claims] 1. A cooling element whose cooling amount changes according to an electric current is provided on an element to be measured mounted on a printed circuit board. By controlling the current of the cooling element, heat between the upper surface of the element to be measured and the cooling element is controlled. The resistance is changed dynamically, and the upper surface heat generation amount and the upper surface temperature and lower surface temperature of the element to be measured before and after the change in the thermal resistance are measured. A method for measuring the calorific value of an electronic component, comprising calculating a calorific value of a device to be measured from a thermal resistance value between a junction and an upper surface of the device. 2. An apparatus for performing the method according to claim 1, further comprising: a calorific value measuring device for measuring an upper surface calorific value of the measurement target element having a cooling element whose cooling amount changes according to an electric current; A temperature measuring device having respective sensors for detecting the upper surface temperature and the lower surface temperature; the calorific value measured by the calorific value measuring device and the junction and the upper surface of the element to be measured which are clarified in each temperature and a maker test; Calculating means for calculating a calorific value of the element to be measured from a thermal resistance value therebetween. 3. A heat generation unit made of a heat conductive member is provided on a device to be measured mounted on a printed circuit board, a cooling device is provided on the heat measurement unit, and the performance of the cooling device is changed. Measure the temperature of the upper and lower surfaces of the device under test and the temperature of the upper surface of the heat generation measurement unit before and after changing the performance, and measure the temperature between the measured temperature and the junction of the device under test and the upper surface that are clarified in the manufacturer test. A method for measuring the calorific value of an electronic component, wherein a calorific value of the element to be measured is calculated from a thermal resistance value. 4. An apparatus for carrying out the method according to claim 3, wherein the heat generation measuring unit is formed of a heat conductive member mounted on a device to be measured mounted on a printed circuit board; A cooling device provided on the portion, a temperature measuring device having respective sensors for detecting the upper surface temperature and the lower surface temperature of the temperature measurement target element and the upper surface temperature of the heat generation measuring portion, and each of the above-described temperature measured by the measuring device. An electronic component calorific value measuring device, comprising: arithmetic means for calculating a calorific value of a device to be measured from a thermal resistance value between a junction and an upper surface of the device to be measured, which is clarified by a temperature and a manufacturer test. 5. The apparatus according to claim 4, wherein the cooling device comprises a Peltier element and a fan. 6. The apparatus according to claim 4, wherein the cooling device comprises a heat sink and a fan. 7. The cooling device according to claim 4, wherein the cooling device has a heat transfer portion at a lower portion, the periphery of which is covered with a heat insulating material, and a heat generation measurement portion mounting hole at the center of the lower surface. The electronic device is characterized in that the measuring section integrally has a heat transfer piece having a projection on an upper portion thereof which fits into a heat measurement section mounting hole of the heat transfer section, and is detachable on a lower surface of the heat transfer section. Component calorific value measurement device. 8. The apparatus according to claim 7, wherein a plurality of heat generation measuring units having different sizes are prepared and can be replaced according to the size of the element to be measured. Electronic component calorific value measuring device.