JP5201371B2 - Electronic component module - Google Patents

Description

  The present invention relates to a surface mount electronic component module. More specifically, the present invention relates to an electronic component module used for mobile communication devices such as mobile phones.

  This type of electronic component module is increasingly becoming increasingly integrated in order to meet the high functionality, miniaturization, and thinning required by mobile communication equipment, which is its main application, and has a limited shape. Various kinds of electronic components are mixed and packed in high density. These electronic parts include chip parts and resin mold parts. The chip component has terminal electrodes attached to both ends of the base, is mounted on one surface of the substrate, and the terminal electrode is soldered to a conductor provided on one surface of the substrate. The resin molded component has an outer surface covered with a mold resin, mounted on one surface of a substrate on which chip components are mounted, and soldered. The board has a connection terminal connected to the conductor on the other side opposite to the one side on which the electronic component is mounted, and the connection terminal is soldered to the mother board. An exterior resin that adheres to and covers the chip component and the resin mold component is attached to one side of the substrate. Such an electronic component module is disclosed in Patent Document 1, for example.

  However, when the above-described electronic component module is soldered on a mother board such as a mobile communication device, solder defects may occur in the terminal electrodes of the chip components that constitute the electronic component module. In this solder failure, between the terminal electrodes provided at both ends of the chip component, a failure mode in which the solder extends in a direction to reduce the distance between the electrodes, and a failure mode in which the solder attached to the terminal electrode is extremely reduced, It was also confirmed that a failure mode in which these failures appear simultaneously is included.

  The failure mode in which the solder extends in the direction of decreasing the distance between the electrodes leads to a short-circuit failure between the terminal electrodes in the worst case, and the failure mode in which the solder adhering to the terminal electrode is extremely reduced is an open failure. Because of this, it can be fatal to the function of this type of electronic component module.

JP 2004-95633 A

  The subject of this invention is providing the electronic component module which can avoid the short circuit defect of a mounting chip component, and an open defect.

  In order to solve the above-described problems, the present invention discloses an electronic component module according to three aspects. These three aspects may be satisfied individually or combined.

  The electronic component module according to the first aspect includes a chip component, a resin molded component, a substrate, and an exterior resin. The chip component has terminal electrodes attached to both ends of a base, is mounted on one surface of the substrate, and the terminal electrode is soldered to a conductor provided on one surface of the substrate. The resin molded component is mounted on the one surface of the substrate on which the chip component is mounted, with an outer surface covered with a mold resin. The substrate has a connection terminal on the other surface opposite to the one surface.

  The exterior resin is in close contact with and covers the chip component and the resin mold component on the one surface side of the substrate.

  The above-described configuration can also be found in a conventional electronic component module. However, as described above, when the electronic component module having this configuration is soldered on a mother board such as a mobile communication device, a solder failure may occur in the terminal electrodes of the chip components constituting the electronic component module. .

Therefore, in the present invention according to the first aspect, attention is paid to the relative relationship between the thermal expansion coefficients of the mold resin and the exterior resin in the resin mold part. That is,
The mold resin has a thermal expansion coefficient αA at 250 ° C.
250 / ° C ≦ αA ≦ 400 / ° C
In the range of
The exterior resin has a thermal expansion coefficient αB at 250 ° C.
70 / ° C ≦ αB ≦ 200 / ° C
It is in the range.

  If there is a relative relationship as described above for the thermal expansion coefficient between the mold resin and the exterior resin in the resin mold part, it is possible to avoid the occurrence of a gap between the exterior resin and the chip part. Therefore, even when the electronic component module is subjected to reflow soldering processing with respect to the mother board, short-circuit failure and open failure do not occur in the chip component.

The electronic component module according to the second aspect focuses on the elastic modulus of the mold resin and the exterior resin,
The mold resin has an elastic modulus βA at 250 ° C.
27 MPa ≦ βA ≦ 1500 MPa
In the range of
The exterior resin has an elastic modulus βB at 250 ° C.
0 MPa ≦ βB <3 MPa
It is in the range.

  In this case, since the effect of pressing the expansion of the mold resin with the exterior resin is generated, it is possible to avoid the exterior resin from being peeled off from the outer surface of the chip part and generating a gap between them.

The electronic component module according to the third aspect focuses on the glass transition point Tg of the mold resin and the exterior resin, and the mold resin has a glass transition point TgA of
95 ° C ≦ TgA ≦ 160 ° C
In the range of
The exterior resin has a glass transition point TgB of
78 ℃ ≦ TgB ≦ 82 ℃
It is in the range.

  Also in the third aspect, it is possible to prevent the exterior resin from being peeled off from the outer surface of the chip component and generating a gap therebetween.

  The conditions according to the first to third aspects may be satisfied individually or some of them may be combined.

  As described above, according to the present invention, it is possible to provide an electronic component module capable of avoiding short circuit defects and open defects of mounted chip components.

It is a fragmentary sectional view of the electronic component module which concerns on this invention. It is the top view which abbreviate | omitted exterior resin in the electronic component module shown in FIG. It is a fragmentary sectional view which shows the state which mounted the electronic component module shown in FIG.1 and FIG.2 on the motherboard. It is a figure which shows the problem of the conventional electronic component module.

  1 and 2, the electronic component module according to the present invention includes a chip component 1, a resin molded component 2, a substrate 3, and an exterior resin 4. The chip component 1 has terminal electrodes 12 and 13 attached to both ends of the base 11, is mounted on one surface of the substrate 3, and the terminal electrodes 12 and 13 are soldered to a conductor 14 provided on one surface of the substrate 3. 15 is soldered.

  The chip component 1 is variously selected according to the type of electronic module and the circuit configuration. The main ones are a chip-shaped ceramic capacitor, a chip-shaped inductor, a chip-shaped resistor, or a composite part thereof. The number and arrangement position thereof are variously changed.

  The outer surface of the resin mold component 2 is covered with the mold resin 21 and mounted on one surface of the substrate 3 on which the chip component 1 is mounted. The resin molded component 2 has a circuit element 22 inside thereof, and has a structure in which the entire circuit element 22 is molded with a mold resin 21. The circuit element 22 is a semiconductor element, a surface acoustic wave element, or the like, and the mold resin 21 is made of a relatively soft synthetic resin from the viewpoint of stress relaxation.

  In an electronic component module used for a mobile communication device, there are generally a plurality of resin mold components 2, and adjacent resin mold components 2 are arranged with an interval X1 of 0.5 mm to 2 mm. Yes. At least one of the chip components 1 is disposed inside the interval X1 and has intervals X2 and X3 of 0.05 mm to 0.08 mm between the resin mold component 2 and the component mounting interval is reduced. In addition, the integration degree is enhanced by downsizing the chip component 1.

  The substrate 3 has a connection terminal 31 on the other surface opposite to the one surface. The substrate 3 is generally composed of LTCC (low temperature co-fired ceramic substrate).

  The exterior resin 4 is in close contact with and covers the chip component 1 and the resin mold component 2 on the one surface side of the substrate 3.

  The above-described configuration can also be found in a conventional electronic component module. However, as described above, when the electronic component module having this configuration is soldered on a mother board such as a mobile communication device, a solder failure occurs in the terminal electrodes 12 and 13 of the chip component 1 constituting the electronic component module. There was a thing. The cause will be described with reference to FIG.

  Referring to FIG. 4, in the electronic component module M, the connection terminal 31 is soldered to the conductor pattern 51 formed on one surface of the mother board 5 by the solder 52. In the electronic component module M, the chip component 1 and the resin mold component 2 are mounted on one surface of the substrate 3 with high integration, and the exterior resin 4 is in close contact with the chip component 1 and the resin mold component 2. It covers these. When the electronic component module M is soldered to the conductor pattern 51 of the mother board 5 with the solder 52, when subjected to reflow treatment, the thermal expansion between the mold resin 21 and the exterior resin 4 of the resin mold component 2 is performed. A thermal stress difference (F1-F2) occurs due to the difference in coefficients. This thermal stress difference (F1-F2) generates a thermal stress that pushes up the exterior resin 4. The exterior resin 4 is in intimate contact with the outer surface of the chip component 1, but when the above-described thermal stress is greater than the adhesion force, the exterior resin 4 is peeled off from the outer surface of the chip component 1 and a gap G is generated between them. .

  On the other hand, the solder 14 adhering to the terminal electrodes 12 and 13 is melted by the reflow heat treatment. The molten solder 14 flows into the gap G described above as shown in FIG. When the adhesion force of the exterior resin 4 to the chip component 1 is large, the chip component 1 is lifted to the exterior resin 4 due to thermal stress, and at least one of the terminal electrodes 12 and 13 is separated from the substrate 3. An open failure occurs.

  One means for solving the above-described problem is to make the melting point of the solder 15 used for soldering the chip component 1 higher than the melting point of the solder 52 when soldering the electronic component module M to the motherboard 5. . Specifically, when the electronic component module M is soldered to the mother board 5, the temperature is around 250 ° C. Therefore, the chip component 1 and the resin molded component 2 of the electronic component module M are soldered with the solder 15 having a melting point of 250 ° C. or higher. It is to attach.

  However, the chip component 1 and the resin mold component 2 mixedly mounted on the substrate 3 have different electromagnetic characteristics, and also have different temperature characteristics and heat resistance characteristics. In order to avoid fluctuations, soldering is generally performed using solder 15 having a melting point of about 220 ° C. If this is soldered at a melting point of 250 ° C. or higher, the originally required characteristics cannot be maintained.

In order to solve this problem, the first aspect focuses on the relative relationship between the thermal expansion coefficients of the mold resin 21 and the exterior resin 4 in the resin mold part 2. That is,
The mold resin 21 has a thermal expansion coefficient αA at 250 ° C.
250 / ° C ≦ αA ≦ 400 / ° C
In the range of
The exterior resin 4 has a thermal expansion coefficient αB at 250 ° C.
70 / ° C ≦ αB ≦ 200 / ° C
It is in the range.

  If the thermal expansion coefficients αA and αB between the mold resin 21 and the exterior resin 4 in the resin mold component 2 have the above-described relative relationship, the thermal stress that pushes up the exterior resin 4 is reduced, and the exterior resin 4 becomes a chip. It is possible to prevent the gap G from being generated by peeling from the outer surface of the component 1.

  Therefore, as shown in FIG. 3, the electronic component module M in which the chip part 1 and the resin molded part 2 are soldered with the solder 15 having a melting point of about 220 ° C. is reflow soldered to the mother board 5 at a temperature of about 250 ° C. Even when the attaching process is performed, short-circuit failure and open failure do not occur in the chip component 1. This will be described with reference to repeated reflow test data.

<Test 1>
A resin having a thermal expansion coefficient αA at 250 ° C. of 250 / ° C. is used as the mold resin 21 of the resin mold component 2, and a thermal expansion coefficient αB at 250 ° C. is 50 / ° C. as the exterior resin 4. Electronic component module samples using seven types of resins (for example, epoxy-based) that are stepwise changed to 60 / ° C , 70 / ° C , 100 / ° C , 150 / ° C , 200 / ° C , 220 / ° C , are repeatedly reflowed. Tested. The resin mold component 2 is a SAW filter (surface acoustic wave filter), and the chip component 1 includes a ceramic chip capacitor.

  Prior to the repeated reflow test, an accelerated moisture absorption treatment was performed as a pretreatment. In the accelerated moisture absorption treatment, a heat treatment was performed at 125 ° C. for 24 hours and then exposed to a humidified environment of 30 ° C. and 60% RH for 192 hours. The number of samples subjected to the test is 100 for each of the seven types of samples described above.

  Thereafter, each sample described above was repeatedly passed through a reflow furnace maintained at 250 ° C. 20 times to inspect for short-circuit defects and open defects. The results are shown in Table 1.

Table 1

<Test 2>
Short and open defects were inspected in the same manner as in Test 1 except that an epoxy resin having a thermal expansion coefficient αA at 250 ° C. of 400 / ° C. was used as the mold resin 21 of the resin mold part 2. The results are shown in Table 2.

Table 2

As is apparent from Tables 1 and 2, if the thermal expansion coefficient αA at 250 ° C. of the mold resin 21 is in the range of 250 / ° C. ≦ αA ≦ 400 / ° C., the thermal expansion at 250 ° C. is obtained as the exterior resin 4. If the coefficient αB is in the range of 70 / ° C. ≦ αB ≦ 200 / ° C. , neither open failure nor short-circuit failure occurs. Even if the thermal expansion coefficient αA at 250 ° C. of the mold resin 21 is in the range of 250 / ° C. ≦ αA ≦ 400 / ° C. , the exterior resin 4 has a thermal expansion coefficient αB at 250 ° C. of less than 70 / ° C. An open defect occurs, and if it exceeds 200 / ° C. , a short circuit defect occurs.

Next, the electronic component module according to the second aspect will be described. The electronic component module according to the second aspect focuses on the elastic modulus of the mold resin 21 and the exterior resin 4,
The mold resin 21 has an elastic modulus βA at 250 ° C.
27 MPa ≦ βA ≦ 1500 MPa
In the range of
The exterior resin 4 has an elastic modulus βB at 250 ° C.
0 MPa ≦ βB <3 MPa
It is in the range.

  That is, the exterior resin 4 is made of a material harder than the mold resin 21. The degree of hardness is represented by the numerical range described above. In this case, since the effect of pressing the expansion of the mold resin 21 by the exterior resin 4 is born, it is possible to avoid the exterior resin 4 from being peeled off from the outer surface of the chip component 1 and generating a gap therebetween. Therefore, even when the electronic component module in which the chip component 1 and the resin molded component 2 are soldered with solder having a melting point of about 220 ° C. is subjected to reflow soldering processing at a temperature of about 250 ° C. on the motherboard, Short-circuit failure and open failure do not occur. Next, repeated reflow test data will be described.

<Test 3>
As the mold resin 21 of the resin mold part 2, a resin (for example, epoxy type) having a modulus of elasticity βA at 250 ° C. of 27 MPa is used, and as the exterior resin 4, the modulus of elasticity βB at 250 ° C. is 0.3 MPa, 1. Samples of four types of electronic component modules using a resin (for example, epoxy type) having a pressure of 0 MPa, 2.3 MPa, and 3.1 MPa were repeatedly subjected to a reflow test. The resin mold component 2 is a SAW filter (surface acoustic wave filter), and the chip component 1 includes a ceramic chip capacitor.

  Prior to the repeated reflow test, an accelerated moisture absorption treatment was performed as a pretreatment. In the accelerated moisture absorption treatment, a heat treatment was performed at 125 ° C. for 24 hours and then exposed to a humidified environment of 30 ° C. and 60% RH for 192 hours. The number of samples subjected to the test is 100 for each of the four types of samples described above.

  Thereafter, each sample described above was repeatedly passed through a reflow furnace maintained at 250 ° C. 20 times to inspect for short-circuit defects and open defects. The results are shown in Table 3. The elastic modulus and the coefficient of thermal expansion are all values of 250 ° C. Furthermore, the elastic modulus and the thermal expansion coefficient were measured by the following methods. First, a resin sample used for measurement was prepared in advance so as to be processed into a shape having a length of 7 mm, a width of 7 mm, and a thickness of 1.25 mm. The measurement apparatus uses a dynamic viscoelasticity measurement apparatus, and a resin sample is mounted on a sample stage of the apparatus. The measurement starts in this state. The measurement applies a certain load to the resin sample, defines the amount of indentation at that time, and adds the temperature to the actual load generated on the resin sample at a certain cycle. The deformation amount of the resin sample is captured. The elastic modulus and thermal expansion coefficient were calculated from the numerical values. The measurement was performed under the following conditions. The load applied to the resin sample was 5N, the pushing amount was 2 μm, the loading period was 1 Hz, and the temperature variable range was 30 to 260 ° C.

Table 3

<Test 4>
A short defect and an open defect were inspected in the same manner as in Test 3 except that a resin having an elastic modulus βA at 250 ° C. of 1071 MPa was used as the mold resin 21 of the resin mold part 2. The results are shown in Table 4 .

Table 4

<Test 5>
A short defect and an open defect were examined in the same manner as in Test 3 except that a resin having an elastic modulus βA at 250 ° C. of 1412 MPa was used as the mold resin 21 of the resin mold part 2. The results are shown in Table 5.

Table 5

<Test 6>
A short defect and an open defect were inspected in the same manner as in Test 3 except that a resin having an elastic modulus βA at 250 ° C. of 1535 MPa was used as the mold resin 21 of the resin mold part 2. The results are shown in Table 6.

Table 6

  As apparent from Tables 3 to 6, the elastic modulus βA of the mold resin 21 at 250 ° C. is in the range of 27 MPa ≦ βA ≦ 1500 MPa, and the elastic modulus βB of the exterior resin 4 at 250 ° C. is 0 MPa ≦ βB. If it is in the range of <3 MPa, no open failure or short-circuit failure occurs in the chip component 1. Regarding the elastic modulus βA at 250 ° C. of the mold resin 21, the data about the region smaller than 27 MPa was not collected because in an actual electronic component module, a resin mold component using a mold resin with such an elastic modulus is Because there is no.

Furthermore, an electronic component module according to a third aspect will be described. The electronic component module according to the third aspect focuses on the glass transition point Tg of the mold resin 21 and the exterior resin 4, and the mold resin 21 has a glass transition point TgA of
95 ° C ≦ TgA ≦ 160 ° C
In the range of
The exterior resin 4 has a glass transition point TgB of
78 ℃ ≦ TgB ≦ 82 ℃
It is in the range.

  Also in the third aspect, it is possible to avoid the exterior resin 4 from being peeled off from the outer surface of the chip component 1 and generating a gap therebetween. Therefore, even when the electronic component module in which the chip component 1 and the resin molded component 2 are soldered with solder having a melting point of about 220 ° C. is subjected to reflow soldering processing at a temperature of about 250 ° C. on the motherboard, Short-circuit failure and open failure do not occur. Next, repeated reflow test data will be described.

<Test 7>
A resin (for example, epoxy type) having a glass transition point TgA of 95 ° C. is used as the mold resin 21 of the resin mold part 2, and a glass transition point TgB of the exterior resin 4 is 51 ° C., 78 ° C., 82 ° C., 106 ° C. Samples of four types of electronic component modules using the above resin were repeatedly subjected to a reflow test. The resin mold component 2 is a SAW filter (surface acoustic wave filter), and the chip component 1 includes a ceramic chip capacitor.

  As a pretreatment for the test, an accelerated moisture absorption treatment was performed. In the accelerated moisture absorption treatment, a heat treatment was performed at 125 ° C. for 24 hours and then exposed to a humidified environment of 30 ° C. and 60% RH for 192 hours. The number of samples subjected to the test is 100 for each of the four types of samples described above.

  Thereafter, each sample described above was repeatedly passed through a reflow furnace maintained at 250 ° C. 20 times to inspect for short-circuit defects and open defects. The results are shown in Table 7. The thermal expansion coefficients αA and αB are values at 250 ° C.

Table 7

<Test 8>
A short circuit defect and an open defect were inspected in the same manner as in Test 7 except that a resin having a glass transition point of 124 ° C. was used as the mold resin 21 of the resin mold part 2. The results are shown in Table 8.

Table 8

<Test 9>
Short circuit defects and open defects were inspected in the same manner as in Test 7 except that an epoxy resin having a glass transition point of 160 ° C. was used as the mold resin 21 of the resin mold part 2. The results are shown in Table 9.

Table 9

<Test 10>
Short and open defects were inspected in the same manner as in Test 7 except that a resin having a glass transition point of 186 ° C. was used as the mold resin 21 of the resin mold part 2. The results are shown in Table 10.

Table 10

As apparent from Tables 7 to 10, the glass transition point TgA of the mold resin 21 is
95 ° C. ≦ TgA ≦ 160 ° C., and the glass transition point TgB of the exterior resin 4 is
If it is in the range of 78 ° C. ≦ TgB ≦ 82 ° C., no open failure or short circuit failure occurs in the chip component 1.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

1 Chip part 2 Resin mold part 21 Mold resin

Claims (2)

An electronic component module including a chip component, a resin molded component, a substrate, and an exterior resin,
The chip component has terminal electrodes attached to both ends of a base, is mounted on one surface of the substrate, and the terminal electrodes are soldered to a conductor provided on one surface of the substrate,
The resin molded component is mounted on the one surface of the substrate on which an outer surface is covered with a mold resin and the chip component is mounted,
The substrate has a connection terminal on the other surface opposite to the one surface,
The exterior resin is in close contact with the chip component and the resin mold component on the one surface side of the substrate, and covers them.
The mold resin has a thermal expansion coefficient αA at 250 ° C.
250 / ° C ≦ αA ≦ 400 / ° C
In the range of
The exterior resin has a thermal expansion coefficient αB at 250 ° C.
70 / ° C ≦ αB ≦ 200 / ° C
Electronic component modules in the range of The electronic component module according to claim 1 ,
The resin mold parts are plural, and the resin mold parts adjacent to each other are arranged at intervals of 0.5 mm to 2 mm,
At least one of the chip components is disposed within the interval, and has an interval of 0.05 mm to 0.08 mm between the resin mold component.
Electronic component module.

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