JP5697354B2 - Mounting board resin sealing method - Google Patents

Description

  The present invention relates to a resin sealing method for a mounting substrate.

  2. Description of the Related Art Conventionally, in the field of electrical / electronic equipment, it has been widely performed to resin-mount a mounting board for electronic components for the purpose of protection from the external environment. When the mounting substrate is resin-sealed, bubbles are likely to be generated due to the scattering of the resin or insufficient filling of the resin between the electronic component and the mounting substrate. Since it becomes easy to be influenced, resin sealing is performed under vacuum in order to prevent generation | occurrence | production of a bubble (for example, refer patent document 1).

  As shown in FIG. 11A, the mounting substrate 102 on which the electronic component 101 is mounted is first installed in the vacuum chamber 103, and the vacuum chamber 103 is evacuated. In this state, the resin 105 in the resin tank 104 is applied to the electronic component 101, and the vacuum state is maintained for a predetermined time. Next, as shown in FIG. 11B, after the mounting substrate 102 is installed in the mold 106, the mold 106 is set in the vacuum chamber 103, and the vacuum chamber 103 is evacuated to form the mold 106. Degas inside. After deaeration, as shown in FIG. 11C, the resin 105 is filled into the mold 106, and after the resin 105 is filled, the resin 105 is heated to be cured.

JP 2008-288433 A

  However, in the mounting substrate resin sealing method described in Patent Document 1, when the electronic component 101 is a component that is not completely sealed, such as an aluminum electrolytic capacitor, the electronic component is filled with the resin 105 under vacuum. There is a possibility that the resin 105 may enter from the non-sealed portion of 101 and cause a problem. Therefore, when such an electronic component 101 is mounted, the resin 105 must be filled under normal pressure. However, if resin sealing is performed under normal pressure or reduced pressure, bubbles are likely to be generated, and reliability in resin sealing is reduced.

  Therefore, an object of the present invention is to provide a highly reliable resin-sealing method for a mounting board under normal pressure or reduced pressure.

In order to achieve the above object, a mounting substrate resin sealing method of the present invention is a mounting substrate resin sealing method in which a mounting substrate on which electronic components are mounted is resin-sealed in a case, And a step of installing the mounting board, and an inclined portion that is provided in a resin-filled space between the side wall of the case and the end of the mounting board and is continuously provided to the bottom of the case. via normal pressure, or possess a step of filling in the case under reduced pressure, the inclined portion
, It is characterized that you have no independent conical.

  The present invention provides a resin sealing method for a mounting substrate that is highly reliable under normal pressure or reduced pressure.

The process perspective view which shows the resin sealing method of the mounting substrate which concerns on 1st Embodiment of this invention. The perspective view which shows the structure of the case of FIG. Process sectional drawing which shows the resin sealing method of the mounting substrate which concerns on 1st Embodiment of this invention. Process sectional drawing which shows the resin sealing method of the mounting substrate which concerns on 1st Embodiment of this invention. Process sectional drawing which shows the resin sealing method of the mounting substrate which concerns on 2nd Embodiment of this invention. Process sectional drawing which shows the resin sealing method of the mounting substrate which concerns on 2nd Embodiment of this invention. Process sectional drawing which shows the resin sealing method of the mounting substrate which concerns on 3rd Embodiment of this invention. The perspective view which shows the modification of the case which concerns on embodiment of this invention. The perspective view which shows the further modification of the case which concerns on embodiment of this invention. Sectional drawing which shows the modification of the resin tank which concerns on embodiment of this invention. The process schematic which shows the resin sealing method of the conventional mounting board | substrate.

  Hereinafter, a resin sealing method for a mounting substrate according to an embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
First, a first embodiment of the present invention will be described with reference to FIGS. First, as shown in FIG. 1, the mounting substrate 1 is installed in the case 2.

  In the mounting substrate 1, components that are not completely sealed such as an aluminum electrolytic capacitor 4a, and electronic components 4 such as a transformer and an IC package 4b are mounted on both sides of a rectangular substrate body 3.

  As shown in FIG. 2, the case 2 is formed in a planar rectangular bottomed cylindrical structure having a bottom 2 a and a side wall 2 b, and the length is the same as the end of the mounting substrate 1 when the mounting substrate 1 is installed. It is formed in a length having a predetermined space S (hereinafter referred to as a resin filling space S) for filling the resin between the side wall 2b of the case and the width of the resin is from the lower side to the upper side of the mounting substrate 1. The side wall 2b is formed slightly higher than the height of the electronic component 4 on the upper surface of the mounting substrate 1 so as to completely cover the mounting substrate 1 with resin.

  In the resin filling space S between the side wall 2b of the case 2 and the end portion of the mounting substrate 1, an inclined portion 5 is provided for smoothly filling the case 2 by reducing the flow rate of the resin. In the present embodiment, the inclined portion 5 is formed in a wedge shape, and two side surfaces are provided in contact with the bottom 2a and the side wall 2b.

  Further, the side surface 5a sandwiched between the two side surfaces has a flat inclined surface inclined at an angle of about 45 degrees from the inner surface of the side wall 2b toward the bottom surface. Resin is dripped and smoothly filled in the case 2 through the inclined surface 5a. Hereinafter, the side surface 5a is referred to as an inclined surface.

  The inclined surface 5a of the inclined portion 5 is not limited to a flat surface, and may be a concave or convex curved surface. In short, as long as it has an inclined surface that can smoothly fill the dropped resin into the case, it may have any shape and inclination angle.

  A plurality of fixing portions 6 are formed on the side wall 2c in the width direction of the case 2 in order to fix the electronic component 4 on the lower surface of the mounting substrate 1 in a state of floating from the bottom 2a of the case 2. In the present embodiment, the fixing portion 6 is formed in a quadrangular prism structure having an inclined upper portion. However, the shape, the formation location, and the number are not limited as long as the mounting substrate 1 can be fixed in a floating state from the bottom 2a.

  The case 2 only needs to be a material having high adhesion to the sealing resin, and is formed of a plastic material such as polyethylene terephthalate, polyamide, polycarbonate, polyphenylene oxide, or the like.

  Next, after the case 2 on which the mounting substrate 1 is installed is dried by a drying device (not shown), the resin 8 in the resin tank 7 is inclined to the inclined surface of the inclined portion 5 of the case 2 as shown in FIG. The case 2 is dropped and filled into the case 2 via the inclined surface 5a, and the case 2 is filled with the resin 8 so as to cover the entire mounting substrate 1. The resin 8 used here is a highly waterproof resin such as a urethane resin, an epoxy resin, or a silicon resin.

  In this way, by filling the resin 8 from the inclined portion 5, the flow rate of the resin 8 is relaxed, and compared with the case where there is no inclined portion 5, the rebound generated at the bottom 2 a when filling the resin 8, Occurrence of vortices that involve air is suppressed.

  Then, after the resin 8 is filled in the case 2, when the resin 8 is left standing for a certain period of time and bubbles generated from the mounting substrate 1 are removed, the case 2 is removed by the heating device 9 as shown in FIG. The resin 8 is cured by heating.

  As described above, according to the first embodiment, by dropping the resin 8 onto the inclined surface 5a of the inclined portion 5 provided in the resin filling space S in the case 2, the flow rate of the resin 8 is reduced and the inclined surface 5a is interposed. The case 2 is filled with the resin 8 smoothly. Therefore, compared with the case where the resin 8 is dropped vertically onto the bottom 2a of the case 2, the generation of bubbles is extremely small when the resin 8 is filled. Accordingly, even when resin sealing is performed under normal pressure or reduced pressure, the generation of bubbles can be suppressed, so that highly reliable mounting substrate resin sealing can be performed.

(Second Embodiment)
Next, a resin sealing method for a mounting substrate according to the second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in that the mounting substrate 3 is installed after filling the resin 8 in the case 2, and the other components have the same configuration. Therefore, only the parts different from the first embodiment are shown, and in the following description, the same components as those in the first embodiment will be omitted, and only different components will be described.

  As shown in FIG. 5, first, the resin 8 in the resin tank 7 is dropped on the inclined surface 5a of the inclined portion 5 of the case 2, thereby relaxing the flow rate of the resin 8 and passing through the inclined surface 5a. The case 2 is filled with a certain amount of resin 8.

  Next, after the mounting substrate 1 is dried, the mounting substrate 1 is placed in the case 2 as shown in FIG. At this time, the mounting substrate 1 is gradually immersed in the resin 8 while being tilted, and is placed on the fixing portion 6 of the case 2 while the space between the substrate body 3 and the electronic component 4 is filled with the resin 8. When the mounting substrate 1 is immersed in the resin 8, when the electronic component 4 such as the IC package 4b having a minute gap between the mounting substrate 1 and the substrate body 3 is reached, the immersion of the mounting substrate 1 is temporarily stopped, and capillary action occurs. Wait until the resin 8 completely fills the minute gap. Thereby, it can install, without generating a bubble between the board | substrate body 3 and the electronic component 4. FIG.

  Then, after the mounting substrate 1 is installed in the case 2, the resin 8 is cured by the same means as in the first embodiment.

  As described above, according to the second embodiment, by dropping the resin 8 onto the inclined surface 5a of the inclined portion 5 of the case 2, the flow rate of the resin 8 is reduced, and the resin smoothly enters the case 2 via the inclined surface 5a. After filling the case 2 with a certain amount of the resin 8, the mounting substrate 1 is gradually immersed in the resin 8 while being inclined and installed in the case 2. Thereby, bubbles generated when the resin 8 is filled can be suppressed, and bubbles generated between the substrate body 1 and the electronic component 2 can be further suppressed. Accordingly, even when resin sealing is performed under normal pressure or reduced pressure, the generation of bubbles can be suppressed, so that highly reliable mounting substrate resin sealing can be performed.

(Third embodiment)
Next, a resin sealing method for a mounting substrate according to a third embodiment of the present invention will be described with reference to FIG. In the present embodiment, a shielding plate 10 that blocks the flow of the resin 8 is further installed on a part of the periphery of the IC package 4b having the minute interval of the above-described embodiment. About another structure, it is the same as the said embodiment.

  According to the third embodiment described above, the shielding plate 10 that blocks the flow of the resin 8 is installed on a part of the periphery of the IC package 4b having a minute interval. Therefore, when the four sides of the IC package 4b are open, there is a possibility that the resin 8 flows from the four sides into the central portion under the IC package 4b, and bubbles remain in the central portion under the IC package 4b. In the present embodiment, air bubbles hardly permeate from three sides and remain in the central portion under the IC package 4b. Accordingly, even when resin sealing is performed under normal pressure or reduced pressure, the generation of bubbles can be suppressed, so that highly reliable mounting substrate resin sealing can be performed.

  The present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the scope of the invention.

  For example, instead of the wedge-shaped inclined portion 5 of the above embodiment, as shown in FIG. 8, a conical inclined portion 11 having an inclined surface 11 a of approximately 45 degrees is used as the side wall 2 b of the case 2 and the end of the mounting substrate 1. It may be provided on the case bottom 2a in the resin filling space S between the resin and the resin, and the resin may be dropped on the apex of the conical shape and slid on the inclined surface 11a to be filled in the case 2. Further, the inclined portion 11 may be a polygonal pyramid shape such as a triangular pyramid, and may have any shape and inclination angle as long as it has an inclined surface that can smoothly fill the dropped resin into the case.

  As shown in FIG. 9, when it is difficult to secure the resin filling space S inside the case 2, the plate-like inclined portion 12 is placed on the upper portion of the side wall 2 b of the case 2, for example, approximately 45 degrees. It is good to provide at an angle. In this case, the resin dropped on the inclined portion 12 flows to the side wall 2b through the inclined portion 12, and is then filled in the case 2 along the inner surface of the side wall 2b. Alternatively, the inclined portion 12 may be detached, and the inclined portion 12 may be removed after the case 2 is filled with resin.

  Further, as shown in FIG. 10, a plate-like inclined portion 13 is provided at the discharge port of the nozzle 7 a of the resin tank 7 at an angle of approximately 45 degrees, and the inclined portion 13 relaxes the flow rate of the resin. Also in this case, since the flow velocity of the resin is relieved by the inclined portion 13, even if the resin drops on the case 2, the generation of bubbles due to the rebound of the resin can be suppressed.

DESCRIPTION OF SYMBOLS 1,102 ... Mounting board 2 ... Case 2a ... Bottom 2b ... Side wall 3 ... Substrate body 4, 101 ... Electronic component 4a ... Aluminum electrolytic capacitor 4b ... IC package 5, 11, 12, 13 ... Inclined part 5a, 11a ... Inclined surface 6 ... Fixing part 7, 104 ... Resin tank 8, 105 ... Resin 9 ... Heating device 10 ... Shielding plate 103 ... Vacuum tank 106 ... Mold S ... Resin filling space

Claims (2)

A mounting substrate resin sealing method in which a mounting substrate on which electronic components are mounted is resin-sealed in a case,
Installing the mounting substrate in the case;
The resin is placed in a resin-filled space between the side wall of the case and the end of the mounting substrate, and is provided under a normal pressure or a reduced pressure through an inclined portion that is continuously provided up to the bottom of the case. Filling the case;
I have a,
The inclined portion has independent implementations resin encapsulation method of a substrate which is characterized that you have no a conical. The inclined portion, claim 1 implemented resin sealing method of the substrate, wherein the has a continuous inclined surface to the bottom of the front SL case.

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