JP3915658B2 - Manufacturing method of electronic parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component having an overcharge prevention circuit used for, for example, a battery pack and the like, and a method for manufacturing the same. About.
[0002]
[Prior art]
Conventionally, for example, some battery packs include an electronic component in which an electronic circuit for preventing overcharge and overdischarge is formed. In this electronic component, a chip component such as an IC chip or a CR component is mounted on one main surface of a wiring board on which a predetermined printed wiring pattern is formed. Without being limited to such a battery pack, various electronic devices incorporate an electronic component in which a chip component is mounted on a wiring board.
[0003]
In this electronic component, after mounting a chip component (chip resistor, chip capacitor, FET, IC, etc.) on the wiring board, the electronic component is sealed with a sealing resin, and this is cut into pieces by a blade. It is manufactured by. A large number of electronic components can be obtained from a so-called single wiring board, thereby improving productivity. This manufacturing method is called chip-on-board (COB), and can be reduced in size and weight.
[0004]
In a COB type electronic component, a sealing treatment with a resin has been performed for waterproofing protection of chip components and wiring. The resin sealing process uses a liquid resin such as an epoxy resin from the viewpoint of workability and manufacturing cost, and is performed by a printing method using a metal mask or a coating method using a dispenser in order to form in a predetermined region. It was. Since this resin sealing process uses a liquid resin, the liquid resin injected into the resin metal mask flows and spreads until the resin is cured when the metal mask is removed. Therefore, in order to stop the flow of the liquid resin, conventionally, the flow of the resin has been prevented after forming an embankment-shaped enclosure with a resin material or the like so as to surround the sealing region or the non-sealing region (for example, patent Reference 1).
[0005]
[Patent Document 1]
Japanese Patent Application No. 2001-223302 [0006]
[Problems to be solved by the invention]
By the way, the conventional prevention of resin flow is to simply block the resin flow with a barrier layer or bank-like layer formed of solder or the like. (A film thickness of the solder) or a sufficient distance (a distance from the resin application position to the barrier layer) is required. However, in order to surely prevent the liquid resin from flowing, it is necessary to strictly control the height of the solder. In addition, it is difficult to form a complicated shape and a small-area sealing region by forming a barrier layer with solder or the like.
[0007]
The present invention has been proposed in view of such a conventional situation, and reliably suppresses the spread of the liquid resin to regulate the resin sealing region and form a complicated shape and a small area sealing region. It is an object of the present invention to provide a method for manufacturing an electronic component that can be used.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, a step of forming a wiring pattern on the substrate, a step of forming a resist layer covering the wiring pattern, and a resist pattern so as to surround a resin sealing region on the resist layer A step of forming, a step of mounting a chip component, a step of installing a resin metal mask so that the mask opening is disposed in a region surrounded by the resist pattern, and a mask opening of the resin metal mask. The method includes a step of injecting a liquid resin, a step of removing the resin metal mask, a step of thermosetting the liquid resin, and a step of dividing the substrate into individual pieces at a predetermined interval.
[0010]
In the present invention, the flow of the liquid resin is suppressed by the surface tension generated at the convex part or the edge part of the concave part having a substantially square cross section so as to surround a predetermined resin sealing region of the wiring board. Since it is not a structure for blocking, the spread of the resin is surely restricted within the resin sealing region without depending on the height of the convex portion or the depth of the concave portion. Moreover, since the said convex part or recessed part is formed with a resist, the cross-sectional shape is formed in the substantially square shape which has an edge, and it can respond also to a complicated shape.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electronic component to which the present invention is applied and a manufacturing method thereof will be described in detail with reference to the drawings.
[0012]
FIG. 1 shows a first embodiment of an electronic component to which the present invention is applied. In the electronic component 10, a wiring pattern 2 made of a metal material such as copper is formed on the wiring substrate 1, and a resist layer 3 is formed so as to cover the wiring pattern 2. The resist layer 3 is made of, for example, a photoresist, and is for protecting the wiring pattern 2 from corrosion or the like and for depositing solder at a predetermined position. The resist layer 3 is formed on the entire surface of the substrate 1. However, the resist layer 3 is exposed at portions that need to be electrically connected to chip components and the like described later, such as connection lands of the wiring pattern 2. An opening is formed.
[0013]
A chip component 4 such as an IC connected to the wiring pattern 2 is mounted and sealed with a resin 5. Here, convex portions 6 that are resist patterns having a substantially square cross section are formed at both ends of the resin 5 so as to surround the resin sealing region, and the resin 5 acts on the edges of the convex portions 6. The spread is suppressed by the surface tension.
[0014]
FIG. 2 shows a plan view of the wiring board 1 before separation. In FIG. 2, the resin 5 is a region surrounded by a solid line, and the convex portion 6 is a region surrounded by a solid line and a dotted line. The resin 5 is provided with a non-sealing region 7 such as a connection terminal with an external terminal, and the non-sealing region 7 is formed by the convex portion 6. Thus, the convex part 6 which is a resist pattern can respond to a complicated sealing shape. In addition, after forming the resin 5, the wiring board 1 is cut along the scrub line A and separated into individual pieces to form the electronic component 10.
[0015]
Next, a manufacturing method for manufacturing the electronic component 10 will be described. 3A to 3G show an example of a resin sealing process to which the present invention is applied.
[0016]
3A to 3B show a wiring board manufacturing process. First, as shown in FIG. 3A, a Cu pattern is formed as a wiring pattern 12 on a substrate 11. The Cu pattern is formed, for example, by using a copper-clad laminated substrate and patterning the surface copper foil by photolithography and etching. After the wiring pattern 12 is formed, a resist layer 13 is formed by a technique such as a photolithography technique so as to cover the wiring pattern 2. This is the first resist formation. For example, a photoresist is used for the resist layer 13, and an opening is formed corresponding to the land portion of the wiring pattern 12.
[0017]
Next, as shown in FIG. 3C, a second resist formation is performed. In this second resist formation, a convex portion 14 of a frame-like resist pattern surrounding the resin sealing region is formed. Therefore, the convex portion 14 is patterned by photolithography using a photoresist. Alternatively, it can be formed by using a printing technique, but in order to make the edge shape sharp, it is preferable to perform patterning by a photolithography technique. In addition, this convex part 14 is formed in thickness about 30-50 micrometers and width about 0.3 mm, for example. The shape is preferably as sharp as possible in order to increase the surface tension generated at the edge.
[0018]
Next, as shown in FIG. 3D, the chip component 15 is mounted. Any chip component 15 may be mounted according to the circuit configuration, such as a bare chip or a CR component.
[0019]
After the chip component 15 is mounted, a resin metal mask 16 is set as shown in FIG. The resin metal mask 16 has a mask opening 16 a for potting resin, and is arranged so that the mask opening 16 a enters the inside of the convex portion 14. Here, the height of the mask opening 16a of the resin metal mask 16 and the distance from the opening end to the edge of the convex portion 14 are important, and it is preferable to set this to an appropriate value according to the viscosity of the resin. For example, the distance from the opening end of the mask opening 16a to the outer peripheral edge of the convex portion 14 is L, the mask height of the mask opening 16a is H, and the viscosity of the liquid resin is 1.4 to 1.9 mm in level height. In this case, it is preferable that L ≧ 0.6 × H. Thereby, the spread by the flow of resin can be suppressed reliably.
The level height refers to the height of the resin from the surface of the substrate after 0.65 g of resin is dropped on the ceramic substrate and held at a temperature of 100 ° C. for 1 hour and after thermosetting.
[0020]
Next, as shown in FIG. 3 (f), a liquid resin 17 is injected (potted) into the mask opening 16 a of the resin metal mask 16. As the liquid resin 17, for example, an epoxy resin or the like is used.
[0021]
Subsequently, as shown in FIG. 3G, the resin metal mask 16 is removed. Thereby, the liquid resin 17 flows out, but the spread of the resin 17 stops here due to the surface tension acting on the edge of the resist pattern 14. In this state, the resin 17 is thermally cured and separated into pieces, thereby completing the electronic component 10 shown in FIG.
[0022]
Next, a second embodiment of the present invention will be described.
FIG. 4 is a diagram for explaining the electronic component 20 according to the second embodiment. In FIG. 4, the same components as those shown in FIGS. 1 to 3 used in the description of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0023]
In the first embodiment described above, the spread of the resin 5 is suppressed by the surface tension acting on the edge of the convex portion 6 of the resist pattern formed on the resist layer 3. On the other hand, the present embodiment is characterized in that the resist layer 3 is provided with the recess 21 and the spread of the resin 5 is suppressed by the surface tension acting on the edge of the recess 21.
[0024]
In the electronic component 20, a wiring pattern 2 is formed on the wiring substrate 1, a resist layer 3 is formed so as to cover the wiring pattern 2, and a recess 21 is formed at a predetermined position of the resist layer 3. The concave portion 21 is formed in the resist layer 3 simultaneously with the opening for electrical connection with the connection land portion of the wiring pattern 2 and the chip component 4.
[0025]
Then, a chip component 4 such as an IC connected to the wiring pattern 2 is mounted and sealed with a resin 5. Here, a concave portion 21 is formed at both ends of the resin 5 so as to surround the resin sealing region, and the spread of the resin 5 is suppressed by the surface tension acting on the edge of the concave portion 21.
[0026]
Next, a manufacturing method for manufacturing the electronic component 20 will be described. Fig.5 (a)-FIG.5 (e) show an example of the resin sealing process to which this invention is applied.
[0027]
5A to 5B show a wiring board manufacturing process. First, as shown in FIG. 5A, a Cu pattern is formed as a wiring pattern 12 on a substrate 11. Then, as shown in FIG. 5B, after the wiring pattern 12 is formed, a resist layer 13 made of, for example, a photoresist covering the wiring pattern 2 is formed by a technique such as a photolithography technique. In the resist layer 13, an opening corresponding to a land portion or the like of the wiring pattern 12 and a frame-shaped concave portion 22 corresponding to and surrounding the resin sealing region are formed. The recess 22 is formed to have a depth (corresponding to the film thickness of the photoresist) of about 2 to 3 μm and a width of about 0.3 mm, for example. The shape is preferably as sharp as possible in order to increase the surface tension generated at the edge.
[0028]
Next, as shown in FIG. 5C, the chip component 15 is mounted. Any chip component 15 may be mounted according to the circuit configuration, such as a bare chip or a CR component.
[0029]
After the chip component 15 is mounted, a resin metal mask 16 is set as shown in FIG. The resin metal mask 16 has a mask opening 16 a for potting resin, and is arranged so that the mask opening 16 a enters the inside of the recess 22. Here, the height of the mask opening 16a of the resin metal mask 16 and the distance from the opening end to the edge of the recess 22 are important, and it is preferable to set this to an appropriate value according to the viscosity of the resin. For example, the distance from the opening end of the mask opening 16a to the inner peripheral edge of the recess 22 is L, the mask height of the mask opening 16a is H, and the viscosity of the liquid resin is 1.4 to 1.9 mm in level height. In this case, it is preferable that L ≧ 0.6 × H. Thereby, the spread due to the flow of the resin can be surely suppressed by the surface tension acting on the edge of the recess 22.
[0030]
Next, a liquid resin 17 is injected (potted) into the mask opening 16 a of the resin metal mask 16. As the liquid resin 17, for example, an epoxy resin or the like is used.
[0031]
Subsequently, as shown in FIG. 5E, the resin metal mask 16 is removed. Thereby, although the liquid resin 17 flows out, the spread of the resin 17 stops here by the surface tension which acts on the edge of the recessed part 22 mentioned above. In this state, the resin 17 is thermally cured and separated into individual pieces, whereby the electronic component 20 shown in FIG. 1 is completed.
【The invention's effect】
As is clear from the above description, according to the present invention, it is possible to reliably suppress the resin flow and regulate the resin sealing region. When potting a resin in a narrow range, it is important how to suppress the flowing part, but the present invention makes good use of surface tension, is easy in process, is effective, and has a large effect. .
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an electronic component of a first embodiment to which the present invention is applied.
FIG. 2 is a plan view showing an electronic component before singulation according to a first embodiment to which the present invention is applied.
FIGS. 3A and 3B are cross-sectional views showing an example of the manufacturing method of the first embodiment to which the present invention is applied, where FIG. 3A is a wiring pattern forming step, FIG. 3B is a resist layer forming step, and FIG. (D) shows a chip component mounting process, (e) shows a resin metal mask installation process, (f) shows a liquid resin injection process, and (g) shows a resin metal mask removal and resin curing process.
FIG. 4 is a cross-sectional view showing an example of an electronic component of a second embodiment to which the present invention is applied.
5A and 5B are cross-sectional views showing an example of a manufacturing method according to a second embodiment to which the present invention is applied, where FIG. 5A is a wiring pattern forming step, FIG. 5B is a concave portion forming step, and FIG. Step (d) shows a resin metal mask installation step, and (e) shows a resin metal mask removal and resin curing step.
[Explanation of symbols]
1, 11 Substrate 2, 12 Wiring pattern 3, 13 Resist layer 4, 15 Chip component 5 Resin 6, 14 Protrusion 16 Resin metal mask 17 Liquid resin 21, 22 Concavity

Claims (2)

Forming a wiring pattern on the substrate;
Forming a resist layer covering the wiring pattern;
Forming a resist pattern on the resist layer so as to surround the resin sealing region;
Mounting chip components; and
A step of installing a resin metal mask so that the mask opening is disposed in a region surrounded by the resist pattern;
Injecting a liquid resin into the mask opening of the resin metal mask;
Removing the resin metal mask;
A step of thermosetting the liquid resin;
Dividing the substrate into pieces at predetermined intervals;
A method for manufacturing an electronic component, comprising: L is the distance from the opening edge of the mask opening to the outer peripheral edge of the resist pattern. 2. The method of manufacturing an electronic component according to claim 1, wherein when the mask height of the mask opening is H and the viscosity of the liquid resin is a predetermined viscosity, L ≧ 0.6 × H.

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