JP2002198631A - Electronic device mounting structure for car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device mounting structure for a car which does not generate cracks in a junction between an electronic device and a substrate even if a temperature changes in a wide range. SOLUTION: An electronic device 2 constituted of an almost rectangular solid-like resin package 2a and a lead 3 is mounted on a soft flexible substrate 1 of large thermal expansion and low Young' modulus. The lead 3 provided to both ends of the resin package 2a is electrically and physically jointed to a pad 5 provided on the flexible substrate 1 by a solder part 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle mounting structure for an electronic device.

[0002]

2. Description of the Related Art Conventionally, a ceramic substrate is mainly used for a vehicle-mounted substrate on which electronic devices are mounted.
7 shows the configuration. The electronic device 2 including the resin package 2a and the leads 3 is mounted on the ceramic substrate 10, and the leads 3 provided at both ends of the resin package 2a are connected to the pads provided on the ceramic substrate 10 by the solder portions 4. 5 is electrically and physically joined.

[0003]

In the above conventional example,
Since the ceramic substrate 10 on which the electronic device 2 is mounted is mounted on a vehicle, the maximum temperature is 125 ° C. or higher, and the minimum temperature is −30.
It is used in a wide temperature range of below ℃. Here, the resin package 2a constituting the electronic device 2 is a rigid body having a large thermal expansion and a high Young's modulus, and the ceramic substrate 10 is a rigid body having a small thermal expansion and a high Young's modulus. As described above, the linear expansion coefficient is significantly different between the resin package 2a and the ceramic substrate 10, and both have high Young's modulus, so that the generated thermal stress increases. That is, when the temperature changes greatly, thermal stress concentrates on the solder portion 4 joining the electronic device 2 and the ceramic substrate 10,
Generate distortion. When this change in temperature is repeated, distortion accumulates and cracks occur in the solder portion 4,
There was a risk of malfunction and a decrease in reliability.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an in-vehicle electronic device in which a crack is not generated at a junction between the electronic device and a substrate even when the temperature changes over a wide range. It is to provide a mounting structure.

[0005]

According to the present invention, there is provided an electronic device comprising a resin package having a lead, and a substrate having a low Young's modulus for mounting the electronic device having a pad joined to the lead. And a brazing material for joining the lead and the pad.

According to a second aspect of the present invention, in the first aspect of the present invention, the substrate is a flexible substrate.

According to a third aspect of the present invention, in the first or second aspect, the brazing material is a conductive resin.

According to a fourth aspect of the present invention, in the first or second aspect, the thickness of the substrate is reduced.

According to a fifth aspect of the present invention, in the first or second aspect, the coefficient of linear expansion of the substrate is substantially the same as the coefficient of linear expansion of the electronic device.

According to a sixth aspect of the present invention, in the first or second aspect, the substrate has a wavy shape on a plate surface immediately below the electronic device.

According to a seventh aspect of the present invention, in the first or second aspect, a space is provided between the substrate and the pad.

According to an eighth aspect of the present invention, in the seventh aspect, a gel is provided in a space between the substrate and the pad.

A ninth aspect of the present invention is characterized in that, in the seventh or eighth aspect, the pad has a wavy shape.

According to a tenth aspect, in the first or second aspect, the substrate is provided with a slit immediately below the electronic device.

According to an eleventh aspect of the present invention, in the tenth aspect of the present invention, the corner of the slit is formed of a curved surface.

A twelfth aspect of the present invention is the tenth or first aspect.
In one aspect of the invention, the slit is a slit having a rectangular wave shape.

According to a thirteenth aspect of the present invention, in the twelfth aspect, the electronic device has leads at both ends, and the rectangular wave-shaped slit is provided at both ends of the electronic device. .

According to a fourteenth aspect, in the twelfth aspect, the electronic device has leads at both ends, and the rectangular wave-shaped slit is provided in a direction perpendicular to both end directions of the electronic device. It is characterized by the following.

The invention of claim 15 is the invention of claim 10 or 1
In one aspect of the invention, the substrate has one surface formed of a polyimide layer on which the electronic device is mounted, the other surface formed of a reinforcing plate, and the slit provided in the reinforcing plate. .

According to a sixteenth aspect, in the fifteenth aspect, the polyimide layer has a shape protruding from the one surface so as to be continuous with a slit provided in the reinforcing plate.

According to a seventeenth aspect, in the first or second aspect, the substrate is provided with a plurality of holes directly below the electronic device.

An eighteenth aspect of the present invention is characterized in that, in the first or second aspect of the present invention, the substrate is provided with a slit along a periphery along an outer edge having leads of the electronic device.

According to a nineteenth aspect of the present invention, in the first or second aspect, the substrate is provided with a slit along a periphery along an outer edge of the electronic device.

According to a twentieth aspect, in the first or second aspect, the electronic device has a substantially rectangular parallelepiped shape, the leads are formed on four sides of an outer edge of the electronic device, and the substrate is A slit is provided around four sides of the outer edge of the electronic device.

[0025]

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

(Embodiment 1) In this embodiment, as shown in FIG. 1, an electronic device 2 composed of a substantially rectangular parallelepiped resin package 2a and leads 3 is mounted on a flexible substrate 1, Leads 3 provided at both ends of 2 a are electrically and physically joined to pads 5 provided on flexible substrate 1 by solder portions 4. In the solder part 4, solder is used as a brazing material.

Here, the resin package 2a constituting the electronic device 2 is a rigid body having a large thermal expansion and a high Young's modulus, and the flexible substrate 1 is a soft material having a large thermal expansion and a low Young's modulus.

Next, FIG. 2 shows an analysis result of equivalent plastic strain of each part when the flexible substrate 1 of the present embodiment and the ceramic substrate 10 of the conventional example are used. The analysis location is
There are six locations on the lead, front, tip front, back, tip back, and lead of the electronic device 2, and the vertical axis is generated on each substrate when the temperature is changed from −45 ° C. to 135 ° C. The ratio of equivalent plastic strain is shown.
According to this analysis result, except for on the leads, the equivalent plastic strain generated in the flexible substrate 1 is smaller than that of the ceramic substrate 10.
Is smaller than the equivalent plastic strain generated in

As described above, when the flexible substrate 1 having a low Young's modulus and being soft is used, the equivalent plastic strain generated is small, the thermal stress is reduced, and the occurrence of cracks in the solder portion 4 can be prevented.

In this embodiment, solder is used as the brazing material, but a conductive resin may be used instead of the solder. In this case, the conductive resin is soft,
The thermal stress can be reduced at the joint between the lead 3 and the pad 5, and the occurrence of cracks in the solder portion 4 can be prevented.

F = σwt (force F generated in the flexible substrate 1, thermal stress σ, width w of the flexible substrate 1,
Since the force F is proportional to the thickness t of the flexible substrate 1 from the thickness t) of the flexible substrate 1, by reducing the thickness t of the flexible substrate 1, the force F generated on the flexible substrate 1 is reduced. The occurrence of cracks in the solder portion 4 can be prevented.

Further, in this embodiment, the flexible substrate 1 is used, but a substrate having a coefficient of linear expansion close to that of the resin package 2a may be used instead of the flexible substrate 1, and in this case, the resin package is used. The difference in the coefficient of linear expansion between the substrate 2a and the substrate is reduced, and the generated thermal stress is reduced, so that the occurrence of cracks in the solder portion 4 can be prevented.

(Embodiment 2) In this embodiment, as shown in FIG. 3, a resin package 2a is provided on a flexible substrate 1.
And an electronic device 2 composed of a lead 3 and
The leads 3 provided at both ends of the resin package 2 a are electrically and physically joined to the pads 5 provided on the flexible substrate 1 by the solder portions 4.

Flexible substrate 1 directly below electronic device 2
Has a wavy shape on the plate surface, and the wavy shape portion acts as a stress relaxation mechanism that reduces thermal stress generated in the flexible substrate 1 by expanding and contracting, and prevents cracks from occurring in the solder portion 4. Can be.

(Embodiment 3) In this embodiment, a space 6 is provided between a pad 5 on the flexible substrate 1 and the flexible substrate 1 as shown in FIG. Means that the flexible substrate 1 is
It is electrically and physically bonded to the pad 5 provided thereon. This space 6 can reduce the stress of the solder portion 4 by relaxing the transmission of stress from the flexible substrate 1 to the solder portion 4, and can prevent the occurrence of cracks in the solder portion 4. The other configuration is the same as that of the first embodiment, and the description is omitted.

(Embodiment 4) In this embodiment, a gel 7 is provided in a space between the pad 5 on the flexible substrate 1 and the flexible substrate 1 as shown in an enlarged view of the joint portion in FIG. The leads 3 are electrically and physically joined to the pads 5 provided on the flexible substrate 1 by the solder portions 4. The gel 7 alleviates the propagation of stress from the flexible substrate 1 to the solder portion 4, reduces the stress of the solder portion 4, and can prevent the occurrence of cracks in the solder portion 4. The other configuration is the same as that of the first embodiment, and the description is omitted.

(Embodiment 5) In this embodiment, as shown in an enlarged view of a joint portion in FIG. 6, the pad 5 on the flexible substrate 1
The lead 3 is electrically and physically joined to the pad 5 provided on the flexible substrate 1 by the solder portion 4. The space 6 can alleviate the stress propagation from the flexible substrate 1 to the solder portion 4 as in the third embodiment, reduce the stress of the solder portion 4 and prevent the occurrence of cracks in the solder portion 4.

In this embodiment, since the pad 5 has a wavy shape, the number of places where the pad 5 and the flexible substrate 1 are bonded is larger than in the third embodiment, so that the bonding strength can be increased.

The other configuration is the same as that of the first embodiment, and the description is omitted. It should be noted that the space 6 of the present embodiment may have a gel as in the fourth embodiment.

(Embodiment 6) In the present embodiment, FIG.
As shown in (a) and (b), an electronic device 2 including a resin package 2a and leads 3 is mounted on a flexible substrate 1, and the leads 3 provided at both ends of the resin package 2a are soldered. Flexible substrate 1 by 4
It is electrically and physically bonded to the pad 5 provided thereon. The flexible substrate 1 has a slit 8 provided directly below the resin package 2a in a direction perpendicular to both ends of the resin package 2a. Since this slit 8 acts so as not to restrict the thermal expansion and contraction of the flexible substrate 1,
The occurrence of cracks in the solder portion 4 can be prevented by reducing the generated thermal stress.

As shown in FIG. 8, if R is provided at the corner 8 a of the slit 8 to form a curved shape, stress concentration on the corner 8 a of the slit 8 can be avoided, and the corner of the slit 8 can be prevented. 8a can be prevented from occurring.

(Embodiment 7) This embodiment is different from the embodiment shown in FIG.
As shown in (a) and (b), an electronic device 2 including a resin package 2a and leads 3 is mounted on a flexible substrate 1, and the leads 3 provided at both ends of the resin package 2a are soldered. Flexible substrate 1 by 4
It is electrically and physically bonded to the pad 5 provided thereon. The flexible substrate 1 is provided with a rectangular wave-shaped spring slit 9 formed directly below the resin package 2a at both ends of the resin package 2a. This spring slit 9
Since the expansion and contraction of the flexible substrate 1 in the Y direction (the direction perpendicular to both ends of the resin package 2a) is reduced, the generated thermal stress can be reduced and the occurrence of cracks in the solder portion 4 can be prevented. .

(Embodiment 8) This embodiment relates to FIG.
As shown in (a) and (b), an electronic device 2 including a resin package 2a and leads 3 is mounted on a flexible substrate 1, and the leads 3 provided at both ends of the resin package 2a are soldered. Flexible substrate 1 by 4
It is electrically and physically bonded to the pad 5 provided thereon. The flexible board 1 is provided with a rectangular wave-shaped spring slit 9 formed immediately below the resin package 2a in a direction perpendicular to both ends of the resin package 2a. The spring slit 9 reduces expansion and contraction of the flexible board 1 in the X direction (both ends of the resin package 2a). Therefore, it is possible to reduce the generated thermal stress and prevent cracks from occurring in the solder portion 4. it can.

(Embodiment 9) In this embodiment, as shown in FIG.
The electronic device 2 composed of the lead 3a and the lead 3 is mounted, and the lead 3 provided at both ends of the resin package 2a is
And electrically and physically joined. The flexible substrate 1 has a plurality of circular holes 10 directly below the resin package 2a. The circular holes 10 are formed in the X direction of the flexible board 1 (both ends of the resin package 2a) and in the Y direction.
Since the expansion and contraction in the direction (perpendicular to both ends of the resin package 2a) are reduced, the generated thermal stress can be reduced, and the occurrence of cracks in the solder portion 4 can be prevented.

(Embodiment 10) This embodiment is different from the embodiment shown in FIG.
As shown in (a) and (b), the flexible substrate 1
It has a two-layer structure in which the upper surface side is a polyimide layer 1a and the lower surface side is a reinforcing plate 1b. The electronic device 2 including the resin package 2a and the leads 3 is mounted on the polyimide layer 1a on which a wiring pattern is formed. Then, the leads 3 provided at both ends of the resin package 2a are electrically and physically bonded to the pads 5 provided on the polyimide layer 1a by the solder portions 4.

Unlike the sixth embodiment, the reinforcing plate 1
Since the slit 11 is provided only in the area b directly below the resin package 2a in a direction perpendicular to both ends of the resin package 2a, the slit 11 is formed on the flexible substrate 1 while the wiring pattern on the polyimide layer 1a is left. It works so as not to restrict the thermal expansion and contraction, reduces the generated thermal stress, and can prevent the occurrence of cracks in the solder portion 4. That is, in the present embodiment, the slit 11
It is not necessary to change the wiring pattern due to the provision of.

As shown in FIG. 13, when the polyimide layer 1a continuous with the slit 11 of the reinforcing plate 1b is pushed in the upper direction to form a pushing portion 12 projecting in the upper direction, the slit 11 shown in FIG. The generated thermal stress can be further reduced as compared with the case of only the above.

(Embodiment 11) This embodiment is different from the embodiment shown in FIG.
As shown in (a) and (b), an electronic device 2 including a resin package 2a and leads 3 is mounted on a flexible substrate 1, and the leads 3 provided at both ends of the resin package 2a are soldered. Flexible substrate 1 by 4
It is electrically and physically bonded to the pad 5 provided thereon. The flexible substrate 1 has slits 8 along the outer edges of both ends of the electronic device 2. This slit 8
Reduces the expansion and contraction in the Y direction (perpendicular to both ends of the resin package 2a) from the outside, so that it is possible to reduce the generated thermal stress and to prevent cracks in the solder portion 4. it can.

Further, as shown in FIG. 15, when the flexible substrate 1 is provided with slits 8 along the four sides of the outer edge of the electronic device 2, the X direction from outside (the resin package 2a
, And expansion and contraction in the Y direction (the direction perpendicular to both ends of the resin package 2a).
The occurrence of cracks in the solder portion 4 can be prevented by reducing the generated thermal stress.

As shown in FIG. 16, when a so-called quad electronic device 2 including a substantially rectangular parallelepiped resin package 2a and leads 3 provided on four sides of the resin package 2a is mounted, The slits 8 provided on the flexible substrate 1 along the four sides of the outer edge of the electronic device 2 allow the X direction (both ends of the resin package 2a) and the Y direction (the resin package 2a)
(In the direction perpendicular to both end directions), the thermal stress to be generated can be reduced, and the occurrence of cracks in the solder portion 4 can be prevented.

[0051]

According to the first aspect of the present invention, there is provided an electronic device having a lead and made of a resin package, a substrate having a pad bonded to the lead and mounting the electronic device with a low Young's modulus, and the lead. Since it is composed of a brazing material for joining the pad and the pad, there is an effect that thermal stress on the substrate can be reduced and cracks can be prevented from occurring at the joint between the lead and the pad.

According to a second aspect of the present invention, in the first aspect of the invention, since the substrate is a flexible substrate, the same effect as that of the first aspect is obtained.

According to a third aspect of the present invention, in the first or second aspect of the present invention, since the brazing material is a conductive resin, thermal stress is reduced at the joint between the lead and the pad, and There is an effect that crack generation can be prevented.

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the thickness of the substrate is reduced, so that it is possible to reduce the force generated on the substrate and prevent the occurrence of cracks at the joint. effective.

According to a fifth aspect of the present invention, in the first or second aspect, the linear expansion coefficient of the substrate is substantially the same as the linear expansion coefficient of the electronic device. There is an effect that the difference is reduced, the thermal stress is reduced, and the occurrence of cracks at the joint can be prevented.

According to a sixth aspect of the present invention, in the first or second aspect of the present invention, the substrate has a wavy shape immediately below the electronic device. This has the effect of reducing stress and preventing cracks from occurring at the joint.

According to a seventh aspect of the present invention, in the first or second aspect of the present invention, a space is provided between the substrate and the pad. It acts as a stress relaxation mechanism that alleviates propagation, reduces the stress at the joint, and has the effect of preventing the occurrence of cracks at the joint.

According to an eighth aspect of the present invention, in the seventh aspect of the present invention, since the gel is provided in the space between the substrate and the pad, the gel between the lead and the pad transmits the stress from the substrate to the joint. This has the effect of acting as a stress relaxation mechanism for reducing the stress, reducing the stress at the joint, and preventing the occurrence of cracks at the joint.

According to a ninth aspect of the present invention, in the invention of the seventh or eighth aspect, since the pad has a wavy shape, the stress at the joint is reduced while securing the adhesive strength between the substrate and the pad. There is an effect that cracks can be prevented from occurring at the joint.

According to a tenth aspect of the present invention, in the first or second aspect of the present invention, the substrate is provided with a slit immediately below the electronic device, so that thermal expansion and contraction are not restricted on the substrate side. Thus, there is an effect that it is possible to prevent the occurrence of cracks at the joint portion by reducing the number of cracks.

According to an eleventh aspect of the present invention, in the tenth aspect of the present invention, since the corner of the slit is formed of a curved surface, stress concentration on the corner of the slit can be avoided.
There is an effect that occurrence of cracks at the corners of the slit can be prevented.

The twelfth aspect of the present invention provides the tenth or the first aspect.
In the first aspect of the present invention, since the slit is a rectangular wave-shaped slit, thermal expansion and contraction can be reduced on the substrate side, thermal stress can be reduced, and cracks can be prevented from being generated at the joint. is there.

According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, the electronic device has leads at both ends, and the rectangular wave-shaped slit is provided at both ends of the electronic device. There is an effect that the expansion and contraction of the substrate in the direction perpendicular to both ends can be relaxed, the generated thermal stress can be reduced, and the occurrence of cracks at the joint can be prevented.

According to a fourteenth aspect, in the twelfth aspect, the electronic device has leads at both ends, and the rectangular wave-shaped slit is provided in a direction perpendicular to both end directions of the electronic device. Therefore, there is an effect that expansion and contraction of the substrate in both end directions of the electronic device can be reduced, and the generated thermal stress can be reduced, so that cracks can be prevented from being generated at the joint.

The invention of claim 15 is the invention of claim 10 or 1
In one aspect of the present invention, one surface of the substrate is a polyimide layer on which the electronic device is mounted, the other surface is a reinforcing plate, and the slit is provided on the reinforcing plate. With the wiring pattern of
It works so as not to restrict the thermal expansion and contraction of the substrate, reduces the generated thermal stress, and has the effect of preventing the occurrence of cracks at the joint.

According to a sixteenth aspect of the present invention, in the invention of the fifteenth aspect, the polyimide layer has a shape protruding from the one surface following the slit provided in the reinforcing plate. The same effect is exerted, and there is an effect that the generated thermal stress can be further reduced.

According to a seventeenth aspect of the present invention, in the first or second aspect of the invention, the substrate has a plurality of holes directly under the electronic device. There is an effect that the expansion and contraction of the substrate in the directions can be reduced, the generated thermal stress can be reduced, and the occurrence of cracks at the joint can be prevented. .

According to an eighteenth aspect of the present invention, in the first or second aspect of the present invention, the substrate is provided with a slit around an outer edge having a lead of the electronic device, so that external stress is reduced by the slit. There is an effect that can be made.

According to a nineteenth aspect of the present invention, in the first or second aspect of the present invention, the substrate is provided with a slit around the outer edge of the electronic device, so that external stress is reduced in both orthogonal directions. There is an effect that can be made.

According to a twentieth aspect of the present invention, in the first or second aspect, the electronic device has a substantially rectangular parallelepiped shape, the leads are formed on four sides of an outer edge of the electronic device, and the substrate is A so-called quad electronic device in which leads are provided on four sides because slits are provided around the four sides of the outer edge of the electronic device.
The same effect as that of No. 9 is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining Embodiment 1 of the present invention.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a third embodiment of the present invention.

FIG. 5 is a configuration diagram showing a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram showing a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram showing a sixth embodiment of the present invention.

FIG. 8 is a partially enlarged view showing a sixth embodiment of the present invention.

FIG. 9 is a configuration diagram showing a seventh embodiment of the present invention.

FIG. 10 is a configuration diagram showing an eighth embodiment of the present invention.

FIG. 11 is a configuration diagram showing a ninth embodiment of the present invention.

FIG. 12 is a configuration diagram 1 showing a tenth embodiment of the present invention.

FIG. 13 is a configuration diagram 2 showing a tenth embodiment of the present invention.

FIG. 14 is a configuration diagram 1 showing an eleventh embodiment of the present invention.

FIG. 15 is a configuration diagram 2 showing an eleventh embodiment of the present invention.

FIG. 16 is a configuration diagram 3 illustrating an eleventh embodiment of the present invention.

FIG. 17 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible board 2 Electronic device 2a Resin package 3 Lead 4 Solder part 5 Pad

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshinobu Momoi 1048 Kazuma Kadoma, Kazuma, Osaka Prefecture F-term in Matsushita Electric Works, Ltd. BC01 BC13

Claims (20)

[Claims] An electronic device comprising a resin package having a lead, a substrate having a low Young's modulus for mounting the electronic device having a pad connected to the lead, and bonding the lead and the pad. An on-vehicle mounting structure for an electronic device, comprising: a brazing material; 2. The mounting structure according to claim 1, wherein the substrate is a flexible substrate. 3. The mounting structure according to claim 1, wherein said brazing material is a conductive resin. 4. The mounting structure according to claim 1, wherein said substrate has a reduced thickness. 5. The mounting structure according to claim 1, wherein a coefficient of linear expansion of the substrate is substantially the same as a coefficient of linear expansion of the electronic device. 6. The mounting structure according to claim 1, wherein the substrate has a wavy shape on a plate surface immediately below the electronic device. 7. The mounting structure according to claim 1, wherein a space is provided between the substrate and the pad. 8. The mounting structure according to claim 7, wherein a gel is provided in a space between the substrate and the pad. 9. The mounting structure according to claim 7, wherein the pad has a wavy shape. 10. The substrate according to claim 1, wherein a slit is provided immediately below the electronic device.
A mounting structure for mounting the electronic device according to the above description. 11. The mounting structure for mounting an electronic device on a vehicle according to claim 10, wherein a corner of said slit is formed of a curved surface. 12. The mounting structure according to claim 10, wherein the slit is a rectangular wave-shaped slit. 13. The on-vehicle mounting structure for an electronic device according to claim 12, wherein the electronic device has leads at both ends, and the rectangular wave-shaped slit is provided in a direction toward both ends of the electronic device. . 14. The electronic device according to claim 12, wherein the electronic device has leads at both ends, and the rectangular wave-shaped slit is provided in a direction perpendicular to both ends of the electronic device. Mounting structure for vehicle. 15. The substrate is characterized in that one surface is a polyimide layer on which the electronic device is mounted, the other surface is a reinforcing plate, and the slit is provided in the reinforcing plate. An in-vehicle mounting structure for an electronic device according to claim 10. 16. The mounting structure for an electronic device according to claim 15, wherein said polyimide layer has a shape protruding from said one surface following said slit provided in said reinforcing plate. 17. The electronic device according to claim 1, wherein the substrate is provided with a plurality of holes directly below the electronic device.
A mounting structure for mounting the electronic device according to the above description. 18. The mounting structure for mounting an electronic device on a vehicle according to claim 1, wherein the substrate has a slit provided along a periphery along an outer edge having a lead of the electronic device. 19. The on-vehicle mounting structure for an electronic device according to claim 1, wherein the substrate is provided with a slit around the outer edge of the electronic device. 20. The electronic device has a substantially rectangular parallelepiped shape, the leads are formed on four sides of an outer edge of the electronic device, and the substrate is provided with slits around the four sides of the outer edge of the electronic device. The mounting structure for mounting an electronic device on a vehicle according to claim 1 or 2.