JPH08172258A - Mounting method of electronic component - Google Patents

Abstract

PURPOSE: To obtain a mounting method in which an electronic component such as a coil with a terminal formed on a side face is mounted on a wiring board in a simple process and in such a way that inessential solder does not creep into a part between the electronic component and the wiring board. CONSTITUTION: In the mounting method of an electronic component, a terminal 9a for the electronic component such as a coil 9 or the like with the terminal formed on a side face is connected to a land 7s on a wiring board 5A. In the mounting method, the land 7a on the wiring board 5A is coated with solder 8 in such a way that the solder does not come into contact with a terminal face 9x in the mounting operation of the electronic component, and the electronic component (the coil) 9 and the wiring board 5A are thermocompression- bonded.

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 a terminal on its side surface, for example, a coil using a rectangular wire on a wiring board.

[0002]

2. Description of the Related Art As shown in FIG. 9, a rectangular wire 2 is sequentially coated with an insulating coating 3 and an adhesive coating 4 to obtain a coated conductive wire 1, which is wound and molded into a coil (flat coil).
Used in motors, deflection yokes, transformers, etc.
Conventionally, as a method of mounting such a coil on a circuit board, the following method (1), (2) or (3) has been used.

(1) First, in order to form a coil terminal,
At the winding start portion and the winding end portion of the coil, the adhesive coating 4 and the insulating coating 3 are stripped to predetermined lengths to expose the rectangular wire 2. This exposed portion becomes a terminal. Next, align the coil at a predetermined position on the wiring board and temporarily bond it,
The land, which is the conductor pattern of the wiring board, is connected to the terminals of the coil by soldering, and the winding hole of the coil is filled with an adhesive to fix the coil to the board.

(2) A thermoplastic adhesive is applied to the coil mounting portion of the wiring board in advance. On the other hand, terminals are formed on the coil in the same manner as (1) above. Then, the coil having the terminals formed thereon is fitted into a positioning jig, and the coil and the wiring board are thermocompression bonded to fix the coil to the wiring board. After that, the terminals of the coil and the lands of the wiring board are connected by hand soldering.

(3) In advance, as shown in FIG. 8A, a thermoplastic adhesive 6 is applied to the coil mounting portion 5a of the wiring board 5, and cream solder 8 is applied on the land 7. On the other hand, the terminal 9a is formed in the coil 9 in the same manner as the above (1). Then, the coil 9 and the wiring board 5 are arranged so that the terminal 9a of the coil and the cream solder 8 on the land 7 overlap each other.
Align with and thermo-compress them. As a result, the coil is fixed to the wiring board, and its terminal 7a is also connected to the land 7 of the wiring board. In the figure, as the wiring board 5, the land 7 and the resist layer 1 are formed on the base material 5x.
3 is formed, and the coil 9
Indicates that it is attached to the carrier sheet 10.

[0006]

However, of the conventional coil mounting methods, the above method (1) has a problem that the number of steps is large and the mounting work is troublesome. In addition, the method of (2) above also has a problem that the step of manual soldering takes time.

The above method (3) is used for the coil 9 and the wiring board 5.
Since the terminals 9a of the coil 9 and the lands 7 of the wiring board 5 are simultaneously fixed to each other, there is an advantage that the number of bonding steps can be reduced. However, as shown in FIG. 8B, when the coil 9 and the wiring board 5 are thermocompression bonded, the land 7
There is a problem that the upper cream solder 8 also enters between the coil 9 and the wiring board 5, and the height of the coil after mounting varies. Further, as shown in FIG. 8C, the solder also enters between the coated conductive wires forming the coil 9, and the coil 9 is partially lifted from the substrate, or a rare short circuit is caused, resulting in an inductance. There is also a problem that the electrical characteristics such as the above are impaired.

As described above, when the electronic component is mounted on the wiring board, the solder enters between the electronic component and the wiring board, and the height of the electronic component after mounting varies.
It is not limited to the case of mounting the coil as described above. Electronic components such as IC chips and resistance elements are also common problems when mounting electronic components having terminals on their side surfaces.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art, and enables electronic parts to be mounted on a wiring board in a simple process, and between the electronic parts and the wiring board. The purpose is to prevent unwanted solder from entering, and to prevent the characteristics of the electronic component from being impaired and the height of the electronic component to vary after mounting.

[0010]

When mounting an electronic component having terminals on its side surface on a wiring board, the present inventors apply solder onto the land of the wiring board as in the method of (3) above. When performing the method of thermocompression bonding the wiring board and the electronic component, it is possible to achieve the above object by separating the solder applied on the land of the wiring substrate from the terminal surface of the electronic component. Heading out, the present invention has been completed.

That is, according to the present invention, in an electronic component mounting method of connecting an electronic component having a terminal on its side surface to a land on a wiring board, solder is applied to the land on the wiring board when mounting the electronic component. Provided is a method for mounting an electronic component, which is characterized in that the electronic component and the wiring board are coated so as not to contact the terminal surface and thermocompression bonded.

Hereinafter, a specific embodiment of the present invention will be described in detail with reference to the drawings by taking as an example the case where a plurality of flat coils attached to a carrier sheet are mounted on a wiring board. In each drawing, the same reference numerals represent the same or equivalent constituent elements.

FIG. 2 is a perspective view of a flat coil alignment sheet 11 in which a plurality of flat coils 9 to be mounted are attached to a carrier sheet 10. When a plurality of flat coils are mounted on a wiring board, using a flat coil alignment sheet 11 in which the flat coils 9 are attached to a carrier sheet 10 as shown in FIG.
As will be described later, when the flat coil 9 and the wiring board 5 are aligned with each other, by inserting the guide pin into the hole 12 of the alignment sheet 11, a plurality of flat coils 9 can be formed.
It is possible to align the wiring board 5 with the wiring board 5 simultaneously and easily with high accuracy. Therefore, workability at the time of mounting can be greatly improved.

As shown in FIG. 9, the flat coil 9 is formed by winding a coated wire 1 in which a rectangular wire 2 is sequentially coated with an insulating coating 3 and an adhesive coating 4. Therefore, when mounting the flat coil 9 on the wiring board, first, the insulating coating and the adhesive coating on the winding start portion of the inner peripheral portion of the flat coil 9 are peeled off to expose the rectangular wire to form the terminal 9b. . Similarly,
The terminals 9a are also formed on the outer peripheral portion of the flat coil 9.

FIG. 3 is a perspective view of a wiring board 5A on which the flat coil 9 shown in FIG. 2 is mounted. As shown in the figure,
In this wiring board 5A, lands 7a and 7b connected to the terminals 9a and 9b of each coil are formed on the base material 5x, and the resist layer 13 is formed on the base material 5x around the lands 7a and 7b. Has been formed. FIG. 1A is a partial cross-sectional view when the wiring board 5A and the flat coil 9 are aligned with each other. As shown in FIG. 1, the land 7a is formed at a position where the surface of the terminal 9a is extended. Terminal surface 9 which is a surface
The position intersects with x. Although the terminal 9b on the inner peripheral portion of the flat coil 9 and the land 7b on the wiring substrate 5A corresponding thereto are not shown in FIG. 1, the connection between the terminal 9b on the inner peripheral portion and the land 7b is not shown. The connection is made in the same manner as the connection between the terminal 9a and the land 7a.

When mounting the flat coil 9 on the wiring board 5A, as shown in FIG.
The thermoplastic adhesive 6 is applied to the coil mounting portion 5a. The thickness of the adhesive 6 depends on the type and adhesive strength of the adhesive, but is usually preferably 20 to 30 μm. The adhesive 6 may be applied by printing or using a dispenser or the like.

Next, the cream solder 8 is applied onto the land 7a, but in the present invention, the cream solder 8 is applied to a position where it does not come into contact with the terminal surface 9x, as shown in FIG.
In this case, the cream solder 8 does not necessarily have to be applied to the land 7a. It suffices that the cream solder 8 is applied so as to be applied to at least the land 7a, and may be applied so as to be applied to both the land 7a and the resist layer 13 as shown in FIG.

As the cream solder 8 used here, it is preferable to use a solder having a thixotropic ratio (JIS Z3284) of 0.6 or more. This makes it possible to form a good solder fillet 17 between the terminal 9a and the land 7a during thermocompression bonding of the flat coil 9 and the wiring board 5A, as will be described later. If the thixotropy ratio is too low, the solder cream 8 will flow and will easily go over the terminal surface 9x and into the lower surface of the flat coil 9, which is not preferable. The cream solder 8 may be applied by printing or using a dispenser or the like.

Next, as shown in FIG. 1B, the flat coil 9 and the wiring board 5A are aligned and the wiring board 5
The flat coil 9 is placed on the adhesive 6 applied to the.
As such a positioning method, as shown in FIG. 4, the wiring board 5A is mounted on the positioning jig 14 so that the hole 16 of the wiring board 5A is inserted into the guide pin 15 of the positioning jig 14. Then, the hole 12 of the flat coil alignment sheet 11 is also placed in the guide pin 1 of the alignment jig 14.
Then, the flat coil 9 and the wiring board 5A are positioned.

Next, using a press, reflow, or the like, the temperature is 160 to 240 ° C. and the thickness is 50 to 500 gf / 1 set.
The flat coil 9 and the wiring board 5A are thermocompression-bonded to each other in a degree. As a result, the cream solder 8 separated from the terminal surface 9x is melted, the molten solder holds the land 7a, and the solder fillet 17 is formed between the terminal 9a and the land 7a as shown in FIG. 1C. To form terminals 9a and lands 7a
And are connected. At the same time, the flat coil 9 and the wiring board 5A are fixed by the adhesive 6.

In this way, the flat coil 9 is mounted on the wiring board 5A. In this case, since the flat coil 9 and the wiring board 5A are bonded with the adhesive 6, the flat coil 9 and the wiring board 5A are bonded. Unnecessary solder does not enter between and. Further, since the cream solder 8 is applied to the position away from the terminal surface 9x of the flat coil 9 before the thermocompression bonding, the molten solder lands on the land during the thermocompression bonding so that the land between the terminal 9a and the land 7a is melted. Only the solder fillet 17 is formed on the surface of the flat coil 9, and the molten solder does not enter between the coated conductors forming the flat coil 9 to partially lift the flat coil 9 from the substrate or cause a rare short circuit. Therefore, electrical characteristics such as inductance are not impaired.

As described above, one embodiment of the mounting method of the present invention has been described by taking the case of mounting the flat coil 9 attached to the carrier sheet 10 on the wiring board 5A as an example. Not limited. For example, in FIG.
Although the case where the land 7a of the wiring board 5A is formed at the position where the land 7a intersects with the terminal surface 9x of the flat coil 9 is shown, as in the wiring board 5B shown in FIG. 5, the land 7a and the terminal surface 9x are You may not want to intersect. Also in this case, as in the example of FIG. 1, the terminals 9a are formed on the flat coil 9, the thermoplastic adhesive 6 is applied to the coil mounting portion 5a on the wiring board 5B, and the cream solder 8 is applied on the land 7a. Is applied to align the flat coil 9 and the wiring board 5B.

The mounting method of the flat coil 9 as described above can be applied to various coils. For example, it can be applied to a stator of a non-printing DC motor, a solenoid coil, a relay coil, a transformer, and the like. Further, not only the coil but also electronic parts such as IC chips and resistance elements can be widely applied when mounting electronic parts having terminals on the side surfaces.

Further, in the above-mentioned example of mounting the flat coil on the wiring board, the flat coil and the wiring board are fixed to each other with a thermoplastic adhesive, but the use of such a thermoplastic adhesive is not always necessary in the present invention. Absent. A thermosetting adhesive, a UV curable adhesive, an anaerobic adhesive or the like can be used depending on the type and application of the electronic component, or the use of the adhesive can be omitted.

[0025]

According to the mounting method of the present invention, unnecessary solder does not enter between the electronic component and the circuit board. Therefore, variation in solder thickness between the electronic component and the circuit board is prevented,
It is possible to make the height of the battery component uniform after mounting. In particular, when the method of the present invention is applied to the mounting of a flat coil, it is possible to prevent a rare short circuit, and it is possible to prevent a change in electrical characteristics such as inductance.

[0026]

EXAMPLES The present invention will be specifically described below based on examples.

Example 1 A flat coil was mounted on a wiring board as shown in FIG. 1 using a flat coil alignment sheet in which the flat coil was attached to a carrier sheet. That is, as the wiring board 5A, a thickness of 1 μm is formed on a polyimide base material having a thickness of 25 μm.
A copper foil having a thickness of 8 μ and a resist layer 13 having a thickness of 8 μm (UV curable resist, FCR90G, manufactured by Asahi Kaken Co., Ltd.) were used. Then, a thermoplastic adhesive SC608 manufactured by Sony Chemicals Co., Ltd. was applied to the coil mounting portion 5a of the wiring board 5A by printing to a thickness of about 25 μm. In addition, the cream solder 8 (SPF60) having a thixo ratio of 0.61 is applied so as to be applied to the land 7a and the resist layer 13.
-165, manufactured by Senju Metal Co., Ltd., and printed to a thickness of about 3
57 μm was applied. In this case, the overlapping distance d1 between the coil terminal surface 9x and the land 7a is about 200 μm, and the distance d2 between the coil terminal surface 9x and the cream solder 8 is about 30 μm.
It was set to 0 μm.

The flat coil 9 was mounted on the wiring board 5A by thermocompression bonding the flat coil 9 and the wiring board 5A at a temperature of 190 ° C. and a pressure of 400 gf for 20 seconds.

The thickness d3 (see FIG. 1 (c)) of the laminated product of the flat coil 9 and the wiring board 5A of the mounting board thus obtained was measured. The same experiment was repeated with 50 samples. The result is shown in FIG. In the figure, broken lines SL,
SU is the lower limit and the upper limit of the appropriate range of the thickness d3 of the laminated product when this mounting board is put to practical use. In all of the examples of the present invention, it can be seen that the thickness d3 of the laminated product is within the appropriate range between the lower limit value and the upper limit value, and the in-specification ratio is 100%.

Comparative Example 1 The flat coil 9 was mounted on the wiring board 5A by repeating Example 1 except that the application position of the cream solder 8 was spread over the entire surface of the land 7a. The thickness d3 of the laminate with the wiring board 5A was measured. The result is shown in FIG. 7. As can be seen from the figure, in the mounting method of the comparative example, the variation in the thickness d3 of the laminated product is large, and the thickness d3 of the laminated product exceeds the upper limit SU.
It can be seen that the in-standard rate is only 64%.

[0031]

According to the present invention, it is possible to mount an electronic component on a wiring board by a simple process and without causing unnecessary solder to enter between the electronic component and the wiring board.
Therefore, the characteristics of the electronic component can be prevented from being impaired after mounting, and the height of the electronic component after mounting can be made uniform.

[Brief description of drawings]

FIG. 1 is a process explanatory diagram of a method of the present invention.

FIG. 2 is an explanatory diagram of a flat coil alignment sheet.

FIG. 3 is an explanatory diagram of a wiring board on which an alignment sheet of flat coils is mounted.

FIG. 4 is an explanatory diagram of a method of aligning a flat coil and a wiring board.

FIG. 5 is a process explanatory diagram of another embodiment of the present invention.

FIG. 6 is a thickness distribution diagram of a laminated product of a flat coil and a substrate according to an example.

FIG. 7 is a thickness distribution diagram of a laminated product of a flat coil and a substrate of a comparative example.

FIG. 8 is a process explanatory diagram of a conventional flat coil mounting method.

FIG. 9 is an explanatory view of a general coated conductor wire for a flat coil.

[Explanation of symbols]

 5, 5A, 5B Wiring board 6 Adhesive 7, 7a, 7b Land 8 Solder 9 Coil (flat coil) 9a, 9b Terminal 9x Terminal surface 10 Carrier sheet 11 Flat coil alignment sheet 17 Solder fillet

Claims (5)

[Claims] 1. A method for mounting an electronic component having a terminal on a side surface, the terminal being connected to a land on a wiring board, wherein solder is contacted with a land on the wiring board to contact a terminal surface when the electronic component is mounted. A method for mounting an electronic component, which is characterized in that the electronic component and the wiring board are thermocompression-bonded so as not to apply. 2. The mounting method for an electronic component according to claim 1, wherein the land on the wiring board is formed at a position intersecting with a terminal surface when mounting the electronic component. 3. The land on the wiring board is formed at a position that does not intersect with the terminal surface when mounting the electronic component.
How to mount the described electronic components. 4. The method of mounting an electronic component according to claim 1, wherein the electronic component is a coil formed by winding a rectangular wire with an insulating layer in between. 5. The method of mounting an electronic component according to claim 1, wherein a solder having a thixotropic ratio of 0.6 or more is used.