JP2020194900A - Electronic circuit device - Google Patents

Abstract

To provide an electronic circuit device capable of facilitating achievement of high-density packaging and airtight structure as well as size reduction and high reliability.SOLUTION: An electronic circuit 20 is configured so that an electronic component is packaged into a recessed part formed at one surface of a packaging substrate and sealed with resin 7 to package the electronic component under an airtight state. At the other surface of the packaging substrate, other electronic components 6b-6d are packaged for high-density packaging. Through a wiring pattern 9, a plurality of electrodes 5 connected with the electronic components are set as a small-sized aggregate of divided electrodes for miniaturization and high reliability.SELECTED DRAWING: Figure 6

Description

The present invention relates to an electronic circuit device in which electronic components are mounted on a mounting board, and more particularly to an electronic circuit device in which electronic components required to be mounted in an airtight state are mounted.

Mobile devices such as smartphones and tablet terminals, wearable devices such as wristwatch-type pedometers, etc. are strongly required to have higher functionality and miniaturization, and the electronic circuit devices mounted on these devices are required to be miniaturized.

In order to reduce the size of an electronic circuit device, it is preferable to mount electronic components on a mounting board at a high density. Various high-density mounted electronic circuit devices have been proposed (for example, Patent Document 1 and the like).

On the other hand, it is known that some electronic components mounted on a mounting board need to be mounted in an airtight state because their characteristics deteriorate due to moisture in the atmosphere and the like. For example, in an all-solid-state battery, a method of maintaining an airtight state by sealing with glass is adopted (Patent Document 2).

JP-A-2002-76561 JP-A-2018-170297

With the conventional high-density mounting structure, electronic components cannot be mounted in an airtight state. Therefore, it is necessary to add a complicated manufacturing process in which the electronic component itself has an airtight structure. In view of such an actual situation, it is an object of the present invention to easily realize a high-density mounting and an airtight structure, and to provide a compact and highly reliable electronic circuit device.

In order to achieve the above object, the electronic circuit device according to claim 1 comprises a mounting surface, a mounting board having a wall portion continuous with the mounting surface and having a U-shaped cross section, and the mounting board. A first electronic component mounted on one surface between the wall portions, a sealing resin filled between the wall portions and covering the first electronic component, and the other surface of the mounting substrate. The side surface orthogonal to the wall portion is provided with the mounted second electronic component, and a part or all of the side surface is made of the sealing resin, and the first electronic component is on the surface of the wall portion. Alternatively, it is an electronic circuit device in which an electrode connected to the second electronic component is exposed, and the electrode includes an electrode composed of an aggregate of a plurality of divided electrodes.

The invention according to claim 2 of the present application is characterized in that, in the electronic circuit device according to claim 1, the first electronic component is an all-solid-state battery.

According to the present invention, an electronic component that is required to be mounted in an airtight state, for example, an all-solid-state battery can be sealed with good airtightness only by sealing with a sealing resin, and an electronic circuit device including the all-solid-state battery can be very easily sealed. Can be formed. On the other hand, electronic components that are not required to be mounted in an airtight state can have a structure in which they are exposed and mounted on a mounting board, and have an advantage that parts can be easily replaced.

In the present invention, the mounting substrate is provided with a continuous wall portion, which facilitates the formation of a split electrode for external extraction. Further, by selecting a material having a coefficient of thermal expansion equal to or close to that of a mother substrate or the like on which an electronic circuit device is mounted, it is possible to improve reliability.

Further, if the wall portion is projected from one side to the other side at a position orthogonal to the wall portions at both ends, the distance between the recesses can be narrowed, so that a large number of electronic circuit devices can be formed on the collective substrate. It will be possible. Since the wall portion protruding from one side to the other has a notch in a part, there is an advantage that the variation in the resin thickness injected in the manufacturing process can be suppressed.

Furthermore, when the electrodes are an aggregate of a plurality of divided electrodes, the heat capacity of each divided electrode can be reduced and the variation thereof can be reduced. As a result, when the solder is mounted, the timing at which the solder melts for each divided electrode is aligned, and the electronic circuit device can be mounted without tilting or misalignment. Further, each divided electrode can be made small, which has an advantage that the solder creeps up to the divided electrode is improved and the mounting reliability is improved. It also has the advantage of improving visibility.

It is a figure explaining the manufacturing process of the electronic circuit apparatus of 1st Example of this invention. It is a figure explaining the manufacturing process of the electronic circuit apparatus of 1st Example of this invention. It is a figure explaining the manufacturing process of the electronic circuit apparatus of 1st Example of this invention. It is a figure explaining the manufacturing process of the electronic circuit apparatus of 1st Example of this invention. It is a figure explaining the manufacturing process of the electronic circuit apparatus of 1st Example of this invention. It is explanatory drawing of the electronic circuit apparatus of 1st Example of this invention. It is a figure explaining the manufacturing process of the electronic circuit apparatus of the 2nd Example of this invention. It is a figure explaining the manufacturing process of the electronic circuit apparatus of the 2nd Example of this invention. It is a figure explaining the manufacturing process of the electronic circuit apparatus of the 3rd Example of this invention. It is explanatory drawing of the electronic circuit apparatus of the 3rd Example of this invention. It is explanatory drawing of the modification of the electronic circuit apparatus of the 3rd Example of this invention.

The electronic circuit device of the present invention can mount electronic components that are required to be mounted in an airtight state and electronic components that are not required to be mounted in an airtight state at high density, and can be further miniaturized and highly reliable. Regarding electronic circuit devices. Hereinafter, examples of the present invention will be described in detail.

The first embodiment of the present invention will be described according to the manufacturing process thereof. First, an assembly substrate 1 made of an epoxy resin or the like is prepared. As the collective substrate 1 of this type, a resin substrate (organic substrate) used in a normal manufacturing process of a semiconductor device can be used. The collective substrate 1 is preferably selected as appropriate according to the material of the mother substrate on which the completed electronic circuit device is mounted. For example, if a material having the same or close coefficient of thermal expansion is selected, the mounting reliability is improved. Can be done. When the assembly board 1 is divided by individualization, it constitutes an individual mounting board.

1A and 1B are explanatory views of an assembly substrate 1 in which a recess 2 is formed, FIG. 1A shows a cross-sectional view, and FIG. 1B shows a plan view. In the example shown in FIG. 1, four electronic circuit devices are formed according to the steps described later. In the collective substrate 1 provided with the recess 2, a double-sided plate 1a having a conductive film having a desired wiring pattern formed on both sides of the insulating layer and a frame plate 1b having a through hole corresponding to the recess 2 are bonded together. Can be prepared.

Wall portions 3 are formed at both ends of the recess 2, and a circular through hole 4 is formed in the collective substrate 1 constituting the wall portion 3. The circular through hole 4 can be formed by using a drill, and can be easily formed at low cost and in a short processing time. Electrodes 5 are formed in the through hole 4 and on the front and back surfaces of the assembly substrate 1. The electrode 5 can be formed by a well-known method such as a plating method. The electrode 5 is conductive with a desired wiring pattern formed on the double-sided plate 1a.

By the way, in this embodiment, the three electrodes 5 form a set of electrode groups 5a, and the electrode groups 5a are configured to be connected to the wiring pattern as described later. In the example shown in FIG. 1, four sets of electrode groups 5a are formed for each electronic circuit device.

Next, as shown in FIG. 2, the electronic component 6a (corresponding to the first electronic component) is mounted in the recess 2. A wiring pattern for connecting to the electronic component 6a is formed on the bottom surface of the recess 2, and the electronic component 6a is connected by a desired method. At this time, since there is no wall or the like in the recess 2 between the recess 2 and the region where the electronic circuit device is to be formed, it is easy to drop the adhesive member to the bottom of the recess 2 for mounting and to transport the electronic components. Can be done. In particular, when the adhesive member is dropped, by adopting a method of applying solder to the bottom surface of the recess 2 using a dispenser, the adhesive member such as solder can be reliably supplied to the bottom surface of the deep recess 2 and mounted. It is preferable because reliability can be ensured. Further, it becomes possible to easily mount a plurality of electronic components in the recess 2.

As the electronic component 6a mounted in the recess 2, it is possible to select an electronic component to be mounted that is required to be mounted in an airtight state. For example, an all-solid-state battery can be selected. In general, the characteristics of an all-solid-state battery deteriorate due to moisture in the atmosphere and the like. Therefore, in order to prevent such deterioration of characteristics, as shown in FIG. 3, a sealing resin 7 such as an epoxy resin is filled in the recess 2 and sealed with the resin. In order to maintain sufficient airtightness, it is necessary to sufficiently cover the surface of the electronic component 6a with the sealing resin 7. Therefore, the depth of the recess 2 (in other words, the height of the wall portion 3) is preferably deeper (higher) than the height of the electronic component 6a mounted on the collective substrate 1. Specifically, when the height of the electronic component 6a is 0.6 mm, the height of the wall portion 3 of the recess 2 is set to about 0.8 mm so that the electronic component 6a can be mounted on the bottom of the recess 2. Even if the height of the adhesive member varies, it is possible to form an airtight structure in which moisture does not enter. When it is necessary to form the sealing resin 7 thicker in order to form the airtight structure, the thickness of the frame plate 1b may be appropriately selected in consideration of the thickness thereof, the height of the electronic component 6a, and the like.

Although FIG. 2 shows an example in which two electronic components 6a that are required to be mounted in an airtight state are mounted, another type of electronic component that is not required to be mounted in an airtight state may be mounted in combination. ..

In this way, the surface of the assembly substrate 1 is flattened by the sealing resin 7 (FIG. 3). The sealing resin 7 used preferably has a viscosity of about 100 Pa · s or less so that it can be dropped from a dispenser and flattened. Further, it is preferable to select, for example, an epoxy resin in consideration of chemical resistance, reflow resistance and the like. By increasing the filling amount of a filler such as silicon dioxide (for example, about 60 wt% or more) and using a resin having a water absorption rate of about 0.3 wt% or less, it is possible to implement an airtight state. When mounting the electronic component 6a, if solder is used, a flux removing step may be added. It should be noted that this flattening is suitable for advancing the manufacturing process described later even when none of the mounted electronic components is required to be airtightly sealed.

After that, another electronic component is mounted on the back surface (corresponding to the other surface) of the assembly substrate 1. In the example shown in FIG. 4, three electronic components 6b, 6c, and 6d (corresponding to the second electronic component) are mounted.

As shown in FIG. 4, in this type of electronic circuit device, electronic components of various sizes are mounted on the collective substrate 1. In such a case, if the electronic components 6b to 6d on the back surface side are mounted and then the electronic components 6a on the front surface side are mounted and resin-sealed, the electronic components 6b to 6d may fall off. Therefore, it is preferable to first perform the step of mounting the electronic component 6a on the surface side and sealing the resin as described above. Of course, it is possible to reverse the process as long as the electronic components do not fall off.

Next, the assembly substrate is individualized. This individualization is performed so that the electrode 5 is exposed on the outer periphery of the electronic circuit device. Specifically, as shown in FIG. 5, for example, a dicing saw is run in a grid pattern in which the central portion of the through hole 4 is the cutting position 8. In the cutting method using a dicing saw, the assembly substrate 1 is cut and removed by a predetermined size. In this embodiment, since the through hole 4 is formed so as to have a relatively small diameter, the end portion of the cutting position 8 is located at the center of the through hole 4 as shown in FIG. The cutting positions 8 between the recesses 2 are arranged so that both ends are located at the center of the through holes 4. The cutting between the recesses 2 does not necessarily have to cut the through holes 4 at both ends in one cutting, and may be configured such that one through hole 4 is cut and then the other through hole 4 is cut. ..

In the example shown in FIG. 5, it is individualized into four electronic circuit devices. In general, the individualization step is performed by attaching to a sheet for fixing the assembly substrate, so that the back surface of the assembly substrate is flattened by filling with a sealing resin means that the assembly substrate or after individualization It is preferable in that the electronic circuit device of the above can be reliably adhered to the sheet. Further, it is preferable that cutting chips do not enter the gap between the wall portion 3 and the electronic component 6a.

FIG. 6 shows a perspective view of the electronic circuit device 20 after the individualization. As shown in FIG. 6, in the individualized electronic circuit device 20, a plurality of electronic components 6b, 6c, and 6d are mounted on the surface of the individualized assembly board (mounting board), and the opposite surface of the mounting board. The electronic component 6a is mounted in a state of being coated with the sealing resin 7. Further, an electrode 5 (corresponding to a divided electrode) for external extraction of an electronic circuit device connected to the wiring pattern 9 is exposed on the wall portion 3.

In this embodiment, the thickness remaining as the wall portion 3 is reduced by reducing the opening diameter of the through hole 4. This indicates that the electronic circuit device can be miniaturized as compared with the case where a through hole having a large opening diameter is formed. On the other hand, cutting so that the wall portions 3 do not remain at both ends in the vertical direction of the drawing also realizes miniaturization.

In the electronic circuit device 20 of this embodiment, a plurality of electronic components 6a to 6d can be mounted at high density, and when the electronic components 6a are required to be mounted in an airtight state, they are coated with a sealing resin. It is possible to seal airtightly with. Further, since the electrode 5 has a structure exposed on the side wall of the electronic circuit device, when mounting the electronic circuit device, a connecting member such as solder crawls up the side wall of the electrode 5, and a reliable connection can be formed by visual inspection. Inspection etc. will be easy. In particular, by forming the electrodes connected to the wiring pattern 9 of this embodiment into a group of electrodes as an aggregate of electrodes 5 having a relatively small shape, each electrode 5 has a small heat capacity, and a solder connection is made for mounting on another substrate. When forming, the timing at which the solder melts is aligned, and it is possible to prevent tilting and misalignment of the electronic circuit device. In addition, the fillet height at which the solder crawls up becomes high, which has the advantage of improving mounting reliability and visibility for determining the quality of the solder connection.

Next, a second embodiment will be described. In the first embodiment, the case where the circular through hole 4 is formed to form the electrode 5 has been described, but the shape of the through hole 4 can be modified.

FIG. 7 is a diagram corresponding to FIG. 1 described in the first embodiment. The shape of the through hole 4 between the recesses 2 is changed to a horizontally long ellipse. In FIG. 7, the through holes 4 at both ends of the drawing are left circular, but the through holes 4 at both ends may be formed into a horizontally long ellipse. The through hole 4 can be formed by router processing or processing by laser irradiation.

Hereinafter, as in the first embodiment, the electronic component 6a is mounted in the recess 2. A wiring pattern for connecting to the electronic component 6a is formed on the bottom surface of the recess 2, and the electronic component 6a is connected by a desired method (corresponding to FIG. 2).

After that, a sealing resin 7 such as an epoxy resin is filled in the recess 2 and sealed with the resin (corresponding to FIG. 3).

After that, another electronic component is mounted on the back surface (corresponding to the other surface) of the assembly substrate 1 (corresponding to FIG. 4).

Next, the assembly substrate is individualized. This individualization is performed by running, for example, a dicing saw in a grid pattern in which the center of the through hole 4 is the cutting position 8 along the cutting position 8 shown in FIG. In the cutting method using a dicing saw, the assembly substrate 1 is cut and removed by a predetermined size. In this embodiment, since the through holes 4 arranged at both ends of the drawing have a relatively small diameter, the ends of the cutting positions 8 are located at the center of the through holes 4 as shown in FIG. Further, the central cutting position 8 is located at the center of the horizontally long elliptical through hole 4, and is arranged so that the divided electrode having the same shape as the divided electrode remaining by cutting the through hole 4 arranged at both ends of the drawing remains. There is. It should be noted that the cutting of the horizontally long elliptical through hole 4 does not necessarily require cutting and removing the central portion by one cutting, and the through hole 4 is configured to cut one side and then the other side. You may.

Even when the through holes 4 arranged at both ends of the drawing have a horizontally long elliptical shape, if the cutting position 8 is arranged at a predetermined position, the electrode 5 remaining uncut can have the same shape. it can.

As a result, the electronic circuit device 20 having the shape shown in FIG. 6 can be obtained. Even if the shape of the through hole 4 is deformed, the completed electronic circuit device 20 has the same shape. Therefore, also in the electronic circuit device 20 of the present embodiment, a plurality of electronic components 6a to 6d are mounted at high density. Further, when the electronic component 6a is required to be mounted in an airtight state, it can be hermetically sealed by coating it with a sealing resin. Further, since the electrode 5 has a structure exposed on the side wall of the electronic circuit device, when mounting the electronic circuit device, a connecting member such as solder crawls up the side wall of the electrode 5, and a reliable connection can be formed by visual inspection. Inspection etc. will be easy. Further, since each electrode 5 has a small heat capacity and is mounted on another substrate, the timing at which the solder melts is aligned when the solder connection is formed, and the inclination and misalignment of the electronic circuit device can be prevented. In addition, the fillet height at which the solder crawls up becomes high, which has the advantage of improving mounting reliability and visibility for determining the quality of the solder connection.

Next, a third embodiment will be described. In the first and second embodiments, the recess 2 formed in the assembly substrate 1 has a vertically long shape. Here, in order to increase the number of electronic circuit devices that can be formed from the collective substrate 1 or to arrange the cutting position 8 for individualization, if the space between the adjacent recesses 2 is narrowed, the wall remaining between the recesses 2 is left. There is a risk that a part of the collective substrate 1 constituting the part will be deformed. Therefore, it is possible to deform the shape of the recess 2.

FIG. 9 is a diagram corresponding to FIG. 1 described in the first embodiment. As shown in FIG. 9, the protrusion 10 can be formed in the recess 2. By arranging the protruding portion 10 at a position to be a cutting region at the time of individualization, the protruding portion 10 does not affect the region on which the electronic component is mounted. The protruding portion 10 extends from one wall portion 3, and the tip thereof provides a gap between the protruding portion 10 and the opposing wall portion 3. This is for example, when the sealing resin is dropped into the recess 2 as described with reference to FIG. 3, the thickness of the sealing resin in the recess 2 becomes uniform.

The protrusion 10 may be formed so that the protrusion 10 is left when the recess 2 is formed, for example, by processing a router.

Hereinafter, as in the first embodiment, the electronic component 6a is mounted in the recess 2, and the sealing resin 7 is filled in the recess 2 for sealing. After that, another electronic component 6b, 6c, 6d is mounted on the back surface (front surface side in FIG. 4) of the assembly substrate 1 to be separated into individual pieces. This individualization is performed by running, for example, a dicing saw in a grid pattern passing through the center of the through hole 4 shown in FIG.

Assuming that the width of the protruding portion 10 is narrower than the cutting width cut and removed by the dicing saw, the protruding portion 10 is cut and removed at the time of individualization, and the electronic circuit device 20 having the shape shown in FIG. 6 is completed. In this case, the mounting substrate has a U-shaped wall surface continuous with the mounting surface, and the side surface orthogonal to the U-shaped wall surface has a structure in which the entire wall portion continuous with the mounting surface is cut out. Further, if the width of the protruding portion 10 is made wider than the width to be cut off and a part of the protruding portion 10 is left, the electronic circuit device 20 having the shape shown in FIG. 10 is completed. In this case, the mounting substrate has a U-shaped side surface that is continuous with the mounting surface, and the side surface orthogonal to this has a structure in which a part of the wall portion continuous with the mounting surface is cut out.

The arrangement of the protrusions 10 is not limited to the case shown in FIG. For example, when the length of the recess 2 is long and it is necessary to form a plurality of projecting portions 10, the arrangement is such that the recesses 2 project from one wall portion toward the opposite wall portion, or both wall portions alternately face each other. It is possible to change the arrangement (staggered structure) so as to project toward the wall portion to be formed, or to change the arrangement of the protruding portions arranged in the adjacent recesses. In particular, when the protruding portion 10 is completely removed at the time of individualization, the protruding portion 10 does not remain in the electronic circuit device, so that various changes can be made. On the other hand, when a part of the protruding portion 10 remains, it is necessary to determine the arrangement of the protruding portion 10 in consideration of the position where the protruding portion 10 remains in the electronic circuit device.

The height of the protruding portion 10 can be changed as appropriate, and if there is a problem such as contact with the dispenser when the adhesive member is dropped into the recess 2, the height of the protruding portion 10 can be lowered. .. If the width of the protruding portion 10 is narrower than the width to be removed by cutting, the protruding portion 10 is cut and removed at the time of individualization, and the electronic circuit device having the shape shown in FIG. 6 can be completed. In this case, the mounting substrate has a U-shaped wall surface continuous with the mounting surface, and the side surface orthogonal to the U-shaped wall surface has a structure in which the entire wall portion continuous with the mounting surface is cut out. Further, if the width of the protruding portion 10 is made wider than the width to be cut off and a part of the protruding portion 10 is left, the electronic circuit device 20 having the shape shown in FIG. 11 is completed. In this case, the mounting substrate has a U-shaped side surface that is continuous with the mounting surface, and the side surface orthogonal to this has a structure in which a part of the wall portion continuous with the mounting surface is cut out.

The above description has been described as a modification of the electronic circuit device described in the first embodiment, but it goes without saying that the above description can be applied to the second embodiment having a different electrode structure.

Although the examples of the present invention have been described above, it goes without saying that the present invention is not limited to these examples. For example, the shape of the electrode 5 can be appropriately changed according to the connection structure with the mother substrate on which the electronic circuit device is mounted. The number of electrodes 5 constituting the aggregate of the divided electrodes can be appropriately changed according to the electronic components mounted on the electronic circuit device and the circuit configuration. For example, an aggregate of one electrode and a plurality of electrodes can be used. It can be configured in combination, configured by combining an aggregate of different numbers of electrodes, and can be changed as appropriate. Further, the number of electronic components mounted on the electronic circuit device can be changed as appropriate.

1: Assembly board, 1a: Double-sided plate, 1b: Frame plate, 2: Recessed part, 3: Wall part, 4: Through hole, 5: Electrode, 6a to 6d: Electronic component, 7: Encapsulating resin, 8: Cutting position , 9: Wiring pattern, 10: Protruding part, 20: Electronic circuit device

Claims (2)

A mounting board provided with a mounting surface and a wall portion continuous with the mounting surface and having a U-shaped cross section.
A first electronic component mounted on one surface between the walls of the mounting board,
A sealing resin filled between the walls and covering the first electronic component,
It comprises a second electronic component mounted on the other surface of the mounting board.
The side surface orthogonal to the wall portion is partially or wholly made of the sealing resin.
An electronic circuit device in which an electrode connected to the first electronic component or the second electronic component is exposed on the surface of the wall portion.
The electrode is an electronic circuit device including an electrode composed of an aggregate of a plurality of divided electrodes. In the electronic circuit apparatus according to claim 1,
An electronic circuit device characterized in that the first electronic component is an all-solid-state battery.

Images