JP2002084063A - Mounting method of electronic part, and electronic circuit device manufactured thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting method of an electronic part for a reduced profile of an electronic circuit device under formation. SOLUTION: An electronic part in which an electrode is formed on both ends is mounted on a substrate on the surface of which a pair of conductive mounting parts are formed. Here, there are provided a process where a fitting hole is formed between the pair of conductive mounting parts which penetrate the substrate, a process where a heat-resistant tape is pasted on the rear surface of the substrate to form a bottom surface having adhesiveness at the fitting hole, a process where the electronic part is placed on the bottom surface of the fitting hole, a process where a solder paste is applied in the regions connecting the electrodes of the electronic part and the conductive mounting parts, a process where a metal plate is placed on the solder paste, a process where the metal plate is connected to the conductive mounting part and an electrode of the electronic part by reflow soldering, and a process where the heat-resistant tape is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting an electronic component having electrodes formed at both ends on a substrate having a pair of conductive mounting portions formed on the surface, and an electronic circuit manufactured by the method. Related to the device.

[0002]

2. Description of the Related Art Generally, an electronic circuit device is formed by mounting various electronic components on a substrate. The electronic circuit device includes, for example, a protection circuit connected to a rechargeable battery inside a battery pack used for a mobile phone or the like and configured to prevent overdischarge or overcharge of the rechargeable battery. There is something. FIG. 4 shows a typical configuration example of such an electronic circuit device. This electronic circuit device 100
Is an example in which surface-mounted electronic components 1a, 1b, and 1c such as a chip-type resistor and a chip-type capacitor are mounted on the surface of a substrate B to form a simple protection circuit.

The electronic components 1a, 1b, 1c are formed in a substantially rectangular parallelepiped shape as shown in FIG. 4, and electrodes T are formed at both ends in the longitudinal direction. Such surface-mounted electronic components 1a, 1b, and 1c are provided with pads 121a, 121b, and 1 serving as conductive mounting portions formed on a substrate 102.
21c and 121d are soldered. These pads 121a, 121b, 121c, 121d are formed at one end of a wiring pattern P formed on the substrate 102 by, for example, a known photolithography method, and the electrodes T of the respective electronic components 1a, 1b, 1c are formed. Are arranged so as to correspond to... That is, as shown in FIG. 4, for the electronic components 1a, 1b, 1c, the pads 121a, 121b, 121
c and the shared pad 121d are formed as a pair.

In order to mount the surface-mounted electronic components 1a, 1b, 1c on the substrate 102 by soldering, a reflow soldering method is often used. In this method, first, each of the pads 121a, 121b, 121c, 12
After applying the solder paste on 1d, the electronic components 1a, 1b, 1c are mounted on the solder paste. At this time,
The electronic components 1a, 1b, 1c are automatically placed using a suction collet or the like. Thereafter, the substrate 102 is placed in a heating furnace, and the solder paste is reflowed (remelted).

According to such a method, the pad 121
By heating and melting the solder paste applied to each of the a, 121b, 121c, and 121d, a plurality of electronic components can be soldered at a time, so that the electronic circuit device 100 can be manufactured at low cost. Can be.

[0006]

However, as described above, when the electronic components 1a, 1b, and 1c are soldered to the surface of the substrate 102, the thickness of the electronic circuit device 100 is determined by the sum of the thickness of the substrate 102 and the thickness of the electronic component 1. Cannot be less than the thickness. Therefore, the size of the rechargeable battery pack formed by housing the electronic circuit device 100 and the rechargeable battery in a container is limited due to the thickness of the electronic circuit device 100. As a result, while miniaturization of portable telephones and the like is demanded, such demands cannot be met.

The present invention has been conceived in view of the above circumstances, and an object of the present invention is to provide a method of mounting an electronic component which can reduce the thickness of an electronic circuit device to be formed. And

[0008]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

In other words, the electronic component mounting method provided by the first aspect of the present invention mounts an electronic component having electrodes formed on both ends on a substrate having a pair of conductive mounting portions formed on the surface. A method of forming a mounting hole that penetrates the substrate between the pair of conductive mounting portions,
Attaching a heat-resistant tape from the back surface of the substrate to form an adhesive bottom surface in the mounting hole, placing an electronic component on the bottom surface of the mounting hole, A step of applying a solder paste to each region extending between each conductive mounting portion, a step of placing a metal plate on the solder paste, and electrodes of the metal plate and the conductive mounting portion and the electronic component Are connected by reflow soldering, and a step of removing the heat-resistant tape is provided.

According to the first aspect of the present invention, since the electronic component is mounted in the mounting hole penetrating the substrate, according to the electronic component mounting method, the thickness of the manufactured electronic circuit device is reduced. Thickness + thickness of the electronic component. That is, the thickness can be smaller than the thickness of the conventional electronic circuit device manufactured by mounting the electronic component on the surface of the substrate.

Further, since the mounting hole has a sticky bottom surface, it is possible to prevent the electronic components mounted on the bottom surface from being displaced. Thus, even when the upper surface of the electrode of the electronic component placed on the bottom surface of the mounting hole is lower than the surface of the substrate, the solder paste applied to the electrode of the electronic component and the solder paste It is possible to prevent the metal plate placed thereon from being separated from each other. Therefore, the metal plate can be securely soldered to the conductive mounting portion and the electrode of the electronic component.

In this way, since each electrode of the electronic component and each conductive mounting portion are connected by the metal plate extending therebetween, the mounting hole is formed to be larger than the electronic component. Even in this case, they can be reliably conducted. Further, by making the mounting hole larger than the electronic component, the electronic component can be easily inserted into the mounting hole in the step of mounting the electronic component on the bottom surface of the mounting hole. Thus, this step can be easily automated using an adsorption collet or the like.

Further, since the metal plate may be disposed so as to extend between the electrode of the electronic component and the conductive mounting portion, it is not necessary to improve the precision of the arrangement of the metal plate. Therefore, if a suction collet or the like is used, the step of mounting the metal plate on the solder paste can be easily automated.

An electronic circuit device provided by the second aspect of the present invention is an electronic circuit device in which electronic components having electrodes formed on both ends are mounted on a substrate having a pair of conductive mounting portions formed on the surface. The electronic component is disposed inside a mounting hole formed so as to penetrate the substrate between the pair of conductive mounting portions, and each electrode of the electronic component and each of the conductive mounting portions. Is characterized by being connected by soldering a metal plate between them.

A second aspect of the present invention is the first aspect of the present invention.
An electronic circuit device manufactured by the electronic component mounting method provided by the aspect. Therefore, the same effects as those of the electronic component mounting method according to the first aspect of the present invention can be obtained.

In a preferred embodiment, the metal plate is made of copper or Ni. Also, by using a metal plate having at least a surface plated with Au plated with Au, the conductivity between the electrodes of the electronic component and the conductive mounting portion can be improved.

Other features and advantages of the present invention will become more apparent from the following description of embodiments of the present invention.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of a series of working steps of a method for mounting an electronic component according to the present invention, and FIG.
Schematic perspective view showing an example of an electronic circuit device according to the present invention,
FIG. 3 is a sectional view taken along the line III-III in FIG. In addition,
In the following, the electronic circuit device A to be manufactured is connected to a rechargeable battery inside a rechargeable battery pack used for a portable telephone or the like to prevent overdischarge or overcharge from the rechargeable battery. Description will be made assuming that a simple protection circuit is configured. In these drawings, the same reference numerals are given to members and parts equivalent to those shown in FIG. 4 showing a conventional example.

As shown in FIG. 2, the electronic circuit device A
Are the electronic components 1a, 1a used in the simplified protection circuit.
b and 1c are mounted on a substrate 2.

Each of the electronic components 1a, 1b, and 1c is a surface-mounted electronic component such as a chip-type resistor or a chip-type capacitor, and has a substantially rectangular parallelepiped shape as shown in FIGS. And electrodes T at both ends in the longitudinal direction.
... are formed.

The substrate 2 is made of a synthetic resin such as a glass epoxy resin or other insulating material, and is formed in a substantially rectangular flat plate shape in plan view. A wiring pattern P made of copper or the like is formed on the surface of the substrate 2 as shown in FIG. A known photolithography method is used for forming the wiring pattern P.
That is, after applying a resist material to a substrate having a copper foil on the surface, performing exposure and development using an exposure mask having a desired pattern formed thereon, removing unnecessary portions of the copper foil by etching. Formed by At this time, the electronic components 1a, 1b, 1c
Pads 21a,
21b, 21c, 21d are formed at one end of the wiring pattern P. These pads 21a, 21b, 21c, 21
d are formed in pairs to correspond to the electrodes T of each of the electronic components 1a, 1b, 1c. That is, as shown in FIG. 1, for the electronic components 1a, 1b, and 1c, the pads 21a, 21b, and 21c and the shared pad 21d are formed so as to form a pair.

Hereinafter, a method of mounting the electronic components 1a, 1b, and 1c will be described in order using the electronic component 1a as an example.

First, as shown in FIGS. 1A and 1B, a mounting hole 3 penetrating the substrate 2 is formed between a pair of pads 21a and 21d. The mounting hole 3 is formed so as to correspond to the electronic component 1a. In the present embodiment, the mounting hole 3 is formed in an oblong shape in a plan view, and is formed so as to be larger than the electronic component 1a so that the electronic component 1a passes through without resistance. ing. Further, it is preferable that the thickness of the substrate 2 is substantially equal to the thickness of the electronic component so that the electronic component does not protrude from the surface of the substrate 2 when the electronic component is mounted in the mounting hole 3.

Next, as shown in FIG.
A heat-resistant tape 4 is stuck from the back surface of the substrate to form an adhesive bottom surface 3 a in the mounting hole 3. This heat resistant tape 4
Is made of polyimide or the like so as not to be melted even at a temperature in the reflow furnace (about 240 ° C.). Further, it is preferable that the heat resistant tape 4 does not leave an adhesive substance on the back surface of the substrate when the electronic component is removed after being mounted.

Next, as shown in FIG. 1C, the electronic component 1a is mounted on the bottom surface 3a of the mounting hole 3. At this time, since the mounting hole 3 is formed so that the electronic component 1a passes without resistance as described above, the electronic component 1a can be easily inserted into the mounting hole 3 when the electronic component is moved. it can. Thus, this step can be easily automated by using an adsorption collet or the like.

Then, as shown in FIG. 1 (4), solder pastes 5 are applied to respective regions extending between the respective electrodes T of the electronic component 1a and the respective pads 21a and 21d.
In this case, for example, a solder paste application mask made of stainless steel is used. This mask for applying solder paste is provided in a region of the surface of the substrate 2 where the solder paste is to be applied, that is, one electrode of the electronic component 1a and the pad 21a.
And an opening formed corresponding to a region extending between the other electrode and the pad 21d. To apply the solder paste 5, a mask for applying the solder paste is set on the substrate 2, the solder paste is injected into the opening, and the injected solder paste is stretched by a squeegee or the like.

Next, as shown in FIG. 1 (5), a metal plate 6 is placed on the solder paste 5. Each of these metal plates 6 is formed in such a size as to extend between each of the electrodes T of the electronic component 1a and each of the pads 21a and 21d. Therefore, as described above, even if the mounting hole 3 is larger than the electronic component 1a, the electrodes T of the electronic component 1a can be reliably connected to the pads 21a and 21d. In the present embodiment, these metal plates 6 are formed in a rectangular thin plate shape from copper or nickel suitable for soldering. Thus, since the metal plates 6 are formed in a thin plate shape, this step can be easily automated by using a suction collet or the like. It is to be noted that the metal plates 6 may be at least plated with Au on the surface to be soldered. In such a case, between the electrodes T of the electronic component 1a and the pads 21a and 21d. Electricity can be improved.

In this step, the metal plates 6 are temporarily joined on the substrate 2 due to the viscosity of the solder paste so as not to be displaced. The mounting hole 3
As described above, the adhesive bottom surface 3a is formed as described above, so that the electronic component 1a placed on the bottom surface 3a
Can be prevented from shifting. Thereby, even when the upper surface of the electrode T of the electronic component 1a placed on the bottom surface 3a of the mounting hole 3 is lower than the surface of the substrate 2, the electrode T is applied to the electrode T of the electronic component 1a. The solder paste and the metal plate 3 placed on the solder paste can be prevented from being separated from each other. Therefore, the state in which the metal plates 6 are temporarily joined on the substrate 2 can be maintained.

The operation up to this point is performed by the electronic parts 1b,
1c is also performed collectively.

Next, the metal plates 6 and the pads 21a, 2
1b, 21c, 21d and electronic components 1a, 1b, 1c
Are connected by reflow soldering. In this step, the metal plates 6 are transferred to the reflow furnace in a state of being temporarily joined, and are soldered in the reflow furnace. Specifically, solder paste 6 ...
The solvent contained therein is evaporated by heating, and the solder component is melted and cooled to form a metal plate 6 and pads 21a, 21a.
b, 21c, 21d and the electrodes T of the electronic components 1 are respectively connected. Therefore, in this step, a plurality of electronic components can be collectively soldered.

Next, as shown in FIG. 3, the heat-resistant tape 4 is removed.

The electronic circuit device A thus manufactured
Then, as shown in FIG. 3, the electronic components 1a, 1b, 1c
Is mounted in the mounting hole 3 penetrating the substrate 2,
The thickness is smaller than the thickness of the substrate 2 + the thickness of the electronic component. Therefore, the electronic circuit device A has a thickness equal to that of the conventional electronic circuit device 10 having electronic components mounted on the surface.
It can be smaller than zero.

Of course, the scope of the present invention is not limited to the above embodiment. For example, metal plate 6
Are formed so as to correspond to the shape of the conductive mounting portion, so that the conductive mounting portion and the metal plate can be reliably connected. Further, the manufactured electronic circuit device A is not limited to being built in a rechargeable battery pack, and may be applied to a small electronic device such as a camera or a video.

[Brief description of the drawings]

FIG. 1 shows an example of a series of working steps of a method for mounting an electronic component according to the present invention, and (1) is a schematic cross section showing a step of forming a mounting hole penetrating a substrate between a pair of conductive mounting portions. FIG. 2 (2) is a schematic cross-sectional view showing a step of attaching a heat-resistant tape from the back surface of the substrate to form an adhesive bottom surface in the mounting hole, and (3) mounting an electronic component on the bottom surface of the mounting hole. FIG. 4D is a schematic cross-sectional view showing a step of applying a solder paste to each region extending between each electrode of the electronic component and each conductive mounting portion, and FIG. FIG. 4 is a schematic cross-sectional view showing a step of placing a metal plate on a metal plate.

FIG. 2 is a schematic perspective view showing an example of an electronic circuit device according to the present invention.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a schematic perspective view showing an example of an electronic circuit device manufactured by a conventional electronic component mounting method.

[Explanation of symbols]

1a, 1b, 1c Electronic component 2 Substrate 3 Mounting hole 3a Bottom of mounting hole 4 Heat resistant tape 6 Metal plate 21a, 21b, 21c, 21d Pad (conductive mounting part)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenjiro Yamazaki 21 Ryozaki-cho, Saiin, Ukyo-ku, Kyoto F-term within ROHM Co., Ltd. (reference) 5E319 AA03 AA09 AC01 BB05 CC33 CD11 GG03

Claims (4)

[Claims] 1. A method of mounting an electronic component having electrodes formed at both ends on a substrate having a pair of conductive mounting portions formed on a surface thereof, wherein the substrate is provided between the pair of conductive mounting portions. Forming an attachment hole that penetrates the substrate; attaching a heat-resistant tape from the back surface of the substrate to form an adhesive bottom surface in the attachment hole; and placing an electronic component on the bottom surface of the attachment hole. A step of applying a solder paste to each region between each electrode of the electronic component and each of the conductive mounting sections; a step of placing a metal plate on the solder paste; and A method of connecting the conductive mounting portion and the electrode of the electronic component by reflow soldering, and a process of removing the heat-resistant tape. 2. An electronic circuit device comprising: an electronic component having electrodes formed at both ends mounted on a substrate having a pair of conductive mounting portions formed on a surface thereof, wherein the electronic component comprises: The electrodes of the electronic component and the conductive mounting parts are respectively soldered to a metal plate across the space between the mounting parts formed so as to penetrate the substrate between the conductive mounting parts. An electronic circuit device characterized by being connected by: 3. The electronic circuit device according to claim 2, wherein said metal plate is made of copper or Ni. 4. The electronic circuit device according to claim 3, wherein said metal plate is plated with Au on at least a surface to be soldered.