JP2005191323A - Method for manufacturing a resin-sheet sealed packaging circuit board and resin sheet for sealing packaging circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a sealed packaging circuit board that can seal a packaging circuit board by a simple equipment in a short time and a resin sheet for sealing the packaging circuit board by the method. <P>SOLUTION: The method comprises a sealing resin sheet placement process for placing a resin sheet 10 for sealing a packaging circuit board with an adhesive layer 14 formed on one side of a thermoplastic resin sheet 12 in a way that the adhesive layer 14 faces the surface of a packaging circuit board 40; a process for heating and softening a sealing resin sheet 10; and a sealing process for generating a pressure difference between the packaging circuit board 40 and the sealing resin sheet 10 in a way that pressure goes lower than that on the surface of the sealing resin sheet 10, and crimping the sealing resin sheet 10 to the packaging circuit board for at least coating and bonding the surface of the packaging circuit board. The resin sheet for sealing the packaging circuit board comprises an adhesive layer on one side of the thermoplastic resin sheet with a melting point of 120°C or higher. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a resin sheet-sealed mounted circuit board in which the mounted circuit board is covered with a moisture-impermeable resin sheet to protect the mounted circuit board from water, humidity, dust, and the like, and the resin sheet-sealed mounted circuit It is related with the resin sheet for mounting circuit board sealing used for the manufacturing method of a board | substrate.

  Mounting circuit boards in which electronic components such as ICs, LSIs, capacitors, transformers, etc. are mounted on circuit boards are widely used in automotive electrical products, computer products, toys, washing machines, refrigerators, microwave ovens, and other household electrical products. Has been. In such a mounted circuit board, the IC and LSI are environmentally sealed with a resin, and the influence of water, humidity, and dust is avoided. However, the circuit board on which the circuit is formed with copper and the capacitors and transformers mounted on it are not environmentally sealed. It may be damaged or malfunction due to vibration.

As materials for protecting the mounting substrate from such environmental fluctuations, a reaction curable silicone rubber sealing material (Non-patent Document 1), a solvent-type coating material (Non-Patent Document 2), and the like are known.
Nitto Denko “Liquid Moisture-proof Sealant” [Searched on November 17, 1991] Internet <URL: http://www.nitto.co.jp/product/datasheet/e parts / 024 /> Hitachi Chemical “HumiSeal” [searched on November 17, 1991] Internet <URL: http://www.hitachi-chem.co.jp/english/product/aprm/002.html>

  However, the sealing materials and coating materials disclosed in Non-Patent Document 1 and Non-Patent Document 2 are coating materials containing a liquid thermosetting material or an organic solvent at room temperature. The environment needs to be improved, and handling is troublesome. Moreover, in order to practically perform the sealing of the mounting circuit board, a large heating device is required for drying and curing, temperature management is indispensable, and material loss cannot be ignored. .

  An object of the present invention is to provide a method for manufacturing a sealed circuit board that can perform environmental sealing of the mounted circuit board in a short time with simple equipment, and a resin sheet for sealing a mounted circuit board used in the manufacturing method. It is to provide.

  In the method for producing a resin sheet-sealed mounted circuit board according to the present invention, a resin sheet for sealing a mounted circuit board having an adhesive layer on one side of a thermoplastic resin sheet is placed so that the adhesive layer faces the surface of the mounted circuit board. A sealing resin sheet disposing step, a heating step of heating and softening the sealing resin sheet, and an outer surface of the sealing resin sheet between the mounting circuit board and the sealing resin sheet A sealing step of forming a pressure difference so as to be a lower pressure than the side, pressing the sealing resin sheet to the mounting circuit board, and covering and bonding at least a surface of the mounting circuit board. To do.

  According to the manufacturing method of the resin sheet sealed mounting circuit board having the above configuration, the mounting circuit board can be sealed in a short time with simple equipment. Even when the mounting circuit board is practically sealed, a large heating device for drying and curing the resin film is not required, temperature management is simple, and material loss can be reduced.

  In addition, since the thermoplastic resin sheet does not shrink during sealing, the circuit board and electronic components are not distorted, and sealing can be performed without generation of voids at the corners and corners of the circuit board and electronic components. . The mounting circuit board may be sealed with the resin sheet only on the surface on which the electronic component is mounted, but may extend to the side surface or the back surface.

  In the above production method, the sealing resin sheet may be heated while being supplied, or may be supplied by moving the sealing resin sheet onto the mounting circuit board in a preheated state. Even if it performs the resin sheet arrangement | positioning process for sealing, and a heating process simultaneously, it is good also as a structure which replaces order. Moreover, it is good also as a structure heated while forming a pressure difference on both surfaces of the resin sheet for sealing after supply.

  In the above method for producing a resin sheet-sealed mounted circuit board, the thermoplastic resin preferably has a melting point of 120 ° C. or higher.

  By using this mounting circuit board sealing resin sheet, the mounting circuit board is protected from environmental fluctuations without damaging the sealing material even when heat is generated by the use of electronic components.

  The resin sheet for mounting circuit board sealing which is another invention is a method for producing a resin sheet sealing mounting circuit board according to claim 1, wherein an adhesive layer is provided on one surface of a thermoplastic resin sheet having a melting point of 120 ° C or higher. It is what is used.

  By using the mounting circuit board sealing resin sheet having such a configuration, the mounting circuit board can be sealed in a short time with simple equipment. In addition, a large heating device for drying and curing the resin film is not required, temperature management is simple, and material loss can be reduced.

  In the above-mentioned mounted circuit board sealing resin sheet, the adhesive is preferably a reactive curable adhesive, a pressure-sensitive adhesive, or a hot melt adhesive.

  Any of these adhesives imparts environmental sealing properties and necessary adhesiveness to the resin sheet for mounting circuit board sealing.

  The resin sheet for mounting circuit board sealing used for the manufacturing method of the resin sheet sealing mounting circuit board of this invention and the manufacturing method of the resin sheet sealing mounting circuit board is demonstrated based on drawing.

  FIG. 1 is a cross-sectional view illustrating a mounting circuit board sealing resin sheet of the present invention. The mounted circuit board sealing resin sheet 10 has a configuration in which an adhesive layer 14 is formed on one surface of a thermoplastic resin sheet 12. A primer layer may be provided between the adhesive layer 14 and the thermoplastic resin sheet 12 as necessary.

  As the resin material constituting the thermoplastic resin sheet 12, a material having a melting point of 120 ° C. or higher and a low moisture permeability is used. Specifically, polypropylene, polyethylene, nylon 6, nylon 66, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, ABS, and other thermoplastic resins, thermoplastic polyurethane elastomers, thermoplastic polyester elastomers, thermoplastic polyamide elastomers, thermoplastics Examples thereof include thermoplastic elastomers such as polyolefin elastomers. It is a preferable aspect that the thermoplastic resin sheet constituting material is made flame retardant by adding a known flame retardant. Moreover, it is a suitable aspect from a viewpoint of protection of an electronic component, and the certainty of an operation | movement, also adding a heat conductive filler and improving heat conductivity. Examples of the filler for improving the thermal conductivity include alumina, beryllia, magnesia, zinc oxide, aluminum nitride, boron nitride and the like.

  The thermoplastic resin sheet 12 is softened by a heating process in the manufacture of a resin sheet-sealed mounting circuit board, and has a shape along the unevenness due to the mounted electronic component, at the corners and corners of the circuit board and electronic component. It is necessary to seal without generating voids. Therefore, the softening point of the thermoplastic resin sheet is preferably 200 ° C. or less, more preferably 180 ° C. or less, and particularly preferably 160 ° C. or less.

  Although the thickness of the thermoplastic resin sheet 12 is not specifically limited, It is preferable that it is 10-500 micrometers. If it is too thin, it may not be able to follow the unevenness of the electronic components mounted on the circuit board and may be damaged, and if it is too thick, the tracking of the corners of the electronic components and the corners formed by the electronic components and the substrate will be reduced. Voids may occur.

  As the adhesive constituting the adhesive layer 14, a thermosetting adhesive, a reaction curable adhesive that cures by irradiation with energy rays such as ultraviolet rays and electron beams, a pressure sensitive adhesive, and a hot melt adhesive can be used. Specifically, epoxy adhesives and polyurethane adhesives as thermosetting adhesives, acrylic UV curable adhesives as reactive adhesives that cure by irradiation with energy rays, acrylic adhesives as pressure sensitive adhesives, etc. Examples of hot melt adhesives such as adhesives and rubber adhesives include polyester hot melt adhesives, nylon hot melt adhesives, polyolefin hot melt adhesives, EVA hot melt adhesives, and the like.

  When a thermosetting adhesive is used as a reactive curable adhesive, for example, when an epoxy resin is used, after curing, a strong adhesive force and adhesion can be realized, and high sealing performance such as high heat resistance can be achieved. It is suitable for sealing a required mounting circuit board.

  Use of a reactive curable adhesive that cures using energy rays such as ultraviolet rays and electron beams cures in a short time, which is preferable in the production of a resin sheet-sealed mounting circuit board that strongly requires a reduction in production time. .

  The pressure-sensitive adhesive is suitable for sealing a mounting circuit board that is required not to give stress to an electronic component. In a resin sheet for mounting circuit board sealing using a pressure-sensitive adhesive, the thermoplastic resin sheet moves slightly so as to follow the surface of the electronic component in the sealing process. Since air accumulation tends to occur, it is desirable that the adhesive strength during heating is small.

  The hot melt adhesive can be bonded only by heating and cooling in a short time, and is preferable in the production of a resin sheet-sealed mounting circuit board that strongly requires a reduction in manufacturing time.

  It is preferable for handling that the adhesive layer constituent material is not fluid at normal temperature, and it is preferable that the adhesive layer constituent material has a melting point equal to or lower than the melting point of the thermoplastic resin sheet 12. When the adhesive flows, as shown in FIG. 5, the gap between the electronic component 42 and the circuit board 40 and the corner P formed by the electronic component 42 and the circuit board 40 flow in the air. It is sealed without generating a reservoir. Although the thickness of an adhesive bond layer is not specifically limited, It is preferable that it is 5-50 micrometers.

  FIG. 2 shows a sealing device suitable for carrying out the method for manufacturing a resin sheet sealed mounting circuit board of the present invention and a method for manufacturing a resin sheet sealed mounting circuit board using the sealing device.

  The sealing device 20 includes a lid body 22 and a container body 24, which can be sealed and pressurized or depressurized. The lid body 22 is rotated by a hinge 36 and is configured to be openable and closable. The cover body 22 is provided with a clip 32 so that the mounting circuit board sealing resin sheet 10 can be held horizontally. The lid 22 is provided with a heater 30 for heating the mounting circuit board sealing resin sheet 10. Further, when the mounting circuit board sealing resin sheet 10 is attached to the lid 22, the internal pressure of the mounting circuit board sealing resin sheet 10 is reduced by suction or injection of the internal air on the side opposite to the mounting circuit board placement side surface. A vent hole 26 is provided for adjusting the above.

  When the mounting body 31 on which the mounting board is placed and the mounting circuit board sealing resin sheet 10 are attached to the container body 24, suction of internal air on the mounting board arrangement side of the mounting circuit board sealing resin sheet 10 or A vent hole 28 is provided for adjusting the internal pressure by injection.

  Further, in addition to the clip 32 that holds the mounting circuit board sealing resin sheet 10, a seal member that seals at least the space between the mounting board and the mounting circuit board sealing resin sheet 10 in a depressurizable manner may be provided.

The process of implementing the manufacturing method of the resin sheet sealing mounting circuit board using the sealing device 20 illustrated in FIG. 2 is as follows.
2-1) The lid 22 is opened and the mounting circuit board sealing resin sheet 10 is mounted by the clip 32 (sealing resin sheet arranging step).
2-2) The mounting circuit board 40 on which the electronic component 42 to be sealed is mounted is placed on the mount 31.
2-3) The lid body 22 is closed, and the space A between the mounting circuit board sealing resin sheet 10 and the lid body 22, the mounting circuit board sealing resin sheet 10, and the container body 24 through the vent holes 26 and 28. The space B formed by the above is simultaneously decompressed.
2-4) The mounted circuit board sealing resin sheet 10 is heated and softened by the heater 30 (heating step).
2-5) When air is sent through the vent hole 26 to return the space A to normal pressure, the softened mounting circuit board sealing resin sheet 10 follows the unevenness of the mounted electronic component as shown in FIG. At the same time as covering the mounting circuit board, it is adhered by an adhesive layer to form a resin sheet sealed mounting circuit board (sealing process). The thermosetting adhesive is cured by a crosslinking reaction by heating, and the hot melt adhesive is solidified by cooling. The energy ray curable adhesive is cured by irradiating with ultraviolet rays or electron beams before being released to normal pressure and taking out the mounted circuit board. The pressure-sensitive adhesive is bonded as it is.

  In the above-described sealing step, the space A is simply set to atmospheric pressure, but further pressurization is also a preferable mode from the viewpoint of preventing generation of voids at corners and corners due to circuit boards and electronic components.

  FIG. 3 shows another preferred implementation of a sealing apparatus suitable for carrying out the method for producing a resin sheet encapsulated mounted circuit board of the present invention and a method for producing a resin sheet encapsulated mounted circuit board using the encapsulating apparatus. The form was shown.

  The sealing device 50 includes an upper frame body 52 and a container body 54. When the mounting circuit board sealing resin sheet 10 is mounted, the mounting circuit board sealing side surface of the mounting circuit board sealing resin sheet 10 and The opposite side is open to the atmosphere. The mounting circuit board sealing resin sheet 10 is configured to be sandwiched between the flange 56 of the upper frame 52 and the flange 57 of the container body 54. Similarly to [Example 1], the upper frame 52 is equipped with a heater 58 for heating the resin sheet 10 for mounting circuit board sealing.

The process of implementing the manufacturing method of the resin sheet sealing mounting circuit board using the sealing apparatus 50 illustrated in FIG. 3 is as follows.
3-1) The upper frame 52 is removed, and the mounting circuit board 40 on which the electronic component 42 to be sealed is mounted is placed on the mount 53.
3-2) The mounting circuit board sealing resin sheet 10 is supplied to cover the container body 54 to the flange 57 (sealing resin sheet arranging step).
3-3) The upper frame body 52 is placed so that the flange 56 faces the flange 57 of the container body 54 so as to sandwich the mounting circuit board sealing resin sheet 10.
3-4) The mounting circuit board sealing resin sheet 10 is heated by the heater 58 (heating step).
3-5) Air is sucked through the vent hole 55 to reduce the space formed by the mounting circuit board sealing resin sheet 10 and the container body 54. When the pressure is returned to normal pressure, the softened mounting circuit board sealing resin sheet 10 becomes a shape along the unevenness of the mounted electronic component 42 as shown in FIG. A resin sheet-sealed mounting circuit board is formed by bonding with an agent layer (sealing step).

Sectional drawing which illustrated the resin sheet for mounting circuit board sealing of this invention The side view which illustrated the sealing device suitable for implementation of the manufacturing method of the resin sheet sealing mounting circuit board The side view which illustrated another sealing device suitable for implementation of the manufacturing method of a resin sheet sealing mounting circuit board Cross-sectional view illustrating resin circuit board Partial sectional view showing the sealed state of the corner of the electronic component and the circuit board

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mounting circuit board sealing resin sheet 12 Thermoplastic resin sheet 14 Adhesive layer 40 Mounting circuit board

Claims (4)

  A sealing resin sheet disposing step for disposing a mounting circuit board sealing resin sheet having an adhesive layer on one side of the thermoplastic resin sheet so that the adhesive layer faces the surface of the mounting circuit board, the sealing A heating step for heating and softening the resin sheet, and forming a pressure difference between the mounting circuit board and the sealing resin sheet so that the pressure is lower than the outer surface side of the sealing resin sheet. A method for manufacturing a resin sheet-sealed mounted circuit board, comprising: a sealing step in which a sealing resin sheet is pressure-bonded to the mounted circuit board, and at least a surface of the mounted circuit board is covered and bonded.   The method for producing a resin sheet-sealed mounted circuit board according to claim 1, wherein the thermoplastic resin has a melting point of 120 ° C. or higher.   The resin sheet for mounting circuit board sealing used for the manufacturing method of the resin sheet sealing mounting circuit board of Claim 1 which has an adhesive bond layer on the single side | surface of a thermoplastic resin sheet whose melting | fusing point is 120 degreeC or more.   The resin sheet for mounting circuit board sealing according to claim 3, wherein the adhesive is one of a reactive curable adhesive, a pressure sensitive adhesive, and a hot melt adhesive.

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