JP2004193187A - Manufacturing method of modular component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a modular component capable of being lower in height and having an enough shielding effect by making use of a manufacturing method of the modular component. <P>SOLUTION: The manufacturing method of the modular component comprises a packaging process for mounting and packaging a packaging component 3 composed of an electronic component on a circuit board 1 with solder around the outermost circumference of the surface layer face of which a ground pattern 5 is formed, a washing process for washing the circuit board 1 on which the packaging component 3 is mounted, a sealing process for forming a sealant 4 by filling epoxy resin on the circuit board 1 on which the packaging component 3 is mounted, and a plating process for forming a plated layer on the whole surface of the sealant 4 and on the surface of the circuit board 1. As a result, the thinner and securely sealed modular component is provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a module component used for various electronic devices, communication devices, and the like.
[0002]
[Prior art]
As shown in FIG. 13, a conventional module component includes a circuit board 21 having at least one mounting component 23 mounted on at least one side, a concave ground electrode 24 provided on a side surface of the circuit board 21, And a metal case 22 provided so as to cover the module, and one end of the metal case 22 is inserted into the concave ground electrode 24 and connected by solder to perform electromagnetic shielding of the module component.
[0003]
As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
[0004]
[Patent Document 1]
JP-A-11-330765
[Problems to be solved by the invention]
In the conventional module component, since the metal case 22 is connected to the side surface of the circuit board 21 by soldering, the circuit board 21 needs to have such a thickness that the metal case 22 can stand on its own. In addition, when the metal case 22 hits the mounting component 23 mounted on the circuit board 21, the electric circuit is short-circuited, and a malfunction of the circuit operation occurs.
[0006]
In order to prevent this, the height of the metal case 22 needs to be higher than the height of the mounting component 23, and the circuit pattern formed by the metal case 22 on the surface of the circuit board 21 and the mounting Since a gap is provided between the circuit board 21 and the metal case 22 so as not to come into contact with the component 23, the terminal formed on the metal case 22 is connected to the side terminal portion of the circuit board 21 at several places, making it difficult to reduce the thickness. Only a sufficient shielding effect was obtained.
[0007]
SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a method for manufacturing a module component that achieves a reduction in the height of the module component and a sufficient shielding effect.
[0008]
[Means for Solving the Problems]
In order to solve this problem, the present invention relates to a mounting step of mounting a mounting component made of an electronic component on a circuit board having a ground pattern formed on the outermost surface of a surface layer and mounting the mounting component by soldering, and a circuit board mounting the mounting component. A sealing step of forming a sealing body by filling an epoxy resin on a circuit board on which the mounted components are mounted, and a circuit board including the ground pattern from above the sealing body. Cutting a portion, a plating step of forming a plating layer on the entire surface of the sealing body and the surface of the circuit board exposed by the cutting, and mounting the mounted component shielded by forming the plating layer on each of the collective substrates. It is possible to provide a module component including a dividing step of cutting and dividing each single substrate.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the first aspect of the present invention, there is provided a mounting step of mounting a mounting component made of an electronic component on a circuit board having a ground pattern formed on an outermost periphery of a surface layer and mounting the mounting component by soldering, and a circuit mounting the mounting component. A washing step of washing the board, a sealing step of filling a circuit board on which the mounted components are mounted with an epoxy resin to form a sealing body, and a plating layer on the entire surface of the sealing body and the surface of the circuit board. This is a method for manufacturing a module component comprising a plating step of forming a metal layer, which eliminates a gap between a circuit board and a metal film and enables reliable shielding.
[0010]
According to a second aspect of the present invention, there is provided a mounting step of mounting a mounting component made of an electronic component on a circuit board having a ground pattern formed on the outermost periphery of a surface layer and mounting the component by soldering, and a circuit mounting the mounting component. A washing step of washing the board, a sealing step of filling the epoxy resin on the circuit board on which the mounted components are mounted to form a sealing body, and a circuit board including the ground pattern from above the sealing body. A cutting step of cutting a part, a plating step of forming a plating layer on the entire surface of the sealing body and a surface of the circuit board exposed by the cutting, and an assembly board in which a mounted component is shielded by forming the plating layer. This is a method for manufacturing module parts that consists of a dividing step of cutting and dividing each single board, and eliminates gaps between the circuit board and the metal film and provides multiple modules at once. It can be produced.
[0011]
According to a third aspect of the present invention, there is provided the module component manufacturing method according to the first or second aspect, wherein a plasma step for attaching a hydroxyl group to the surface of the circuit board is added before the sealing step. In addition, the adhesive strength between the circuit board and the sealing resin can be increased.
[0012]
The invention according to claim 4 of the present invention is the method for manufacturing a module component according to claim 1 or 2, wherein the resin is cured in two stages at different temperatures as a sealing step. Can be provided.
[0013]
The invention according to claim 5 of the present invention is the method for manufacturing a module component according to claim 1 or 2, wherein the plating step comprises a two-stage plating step of an electroplating step after an electroless plating step. The shield characteristics at the boundary between the sealing body and the circuit board can be improved.
[0014]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
(Embodiment 1)
In the module component according to the first embodiment of the present invention, as shown in the perspective view of FIG. 1, a metal film 2 is formed on a circuit board 1 formed of a multilayer board. FIG. 2 shows a sectional view of the module component shown in FIG. As shown in the cross-sectional view, a ground pattern 5 and a wiring pattern 40 are formed on at least two or more wiring layers on the inner and outer layers of the circuit board 1. A ground pattern 5 is formed on the outermost peripheral portion of the surface layer of the circuit board. Further, the wiring pattern 40 on the surface layer is electrically connected to the mounted component 3, and the sealing body 4 is covered so as to cover the mounted component 3. Has formed. By covering the sealing body 4 and the ground pattern 5 with the metal film 2, an electric circuit constituted by the mounting component 3 and the wiring pattern 40 of the circuit board 1 is shielded.
[0016]
The manufacturing process of this module component will be described with reference to FIGS.
[0017]
FIG. 3A shows an electrode 10 provided for mounting the mounting component 3 on the circuit board 1. In FIG. 3B, a metal plate 12 provided with a through pattern having substantially the same shape as the electrode 10 is formed, and the through hole 13 of the metal plate 12 and the electrode 10 on the circuit board 1 are aligned so as to coincide with each other. I do. As the metal plate, a metal plate made of stainless steel having a thickness of 150 microns or less is used.
[0018]
Then, a lead-free solder 20 containing 90% or more of Sn and kneaded with a metal powder and a flux component is supplied onto the aligned metal plate 12, and lead squeegee 17 is applied to the lead through the through hole 13 on the metal plate 12. The free solder 20 is extruded and the lead-free solder 20 is supplied onto the electrodes 10 on the circuit board 1. After the supply, the metal plate 12 is pulled up substantially vertically from the circuit board 1 and the supply of the lead-free solder 20 to the electrodes 10 on the circuit board 1 is completed.
[0019]
Next, as shown in FIG. 3C, the mounting component 3 such as a resistor, a capacitor, a coil, a semiconductor, and a crystal is mounted on the electrode 10 to which the lead-free solder 20 is supplied. The circuit board 1 on which the mounted components 3 are mounted is placed in a reflow furnace and heated, and the lead-free solder 20 is melted to connect the mounted components 3 to the circuit board 1.
[0020]
After the reflow, the flux remaining on the surface of the circuit board 1 is washed as shown in FIG. The flux is immersed in a cleaning liquid 25 containing an alcohol or a surfactant in an ultrasonic cleaning machine 26 to perform ultrasonic cleaning. The cleaning device is not limited to the ultrasonic cleaning device 26, but may be a method in which a water flow of the cleaning liquid 25 is created in the cleaning device and is repeatedly washed on the mounting surface of the circuit board 1. Subsequently, the substrate is sufficiently washed with pure water and dried. In order to prevent the moisture absorbed by the circuit board 1 from being dried by this drying and to prevent the water vapor released from the inside of the circuit board 1 from deteriorating the adhesion strength between the sealing body 4 and the surface of the circuit board 1 in the next sealing step, Dry at 125 ° C. for 2 hours or more.
[0021]
Next, the activated surface of the circuit board 1 is irradiated with oxygen activated by the plasma generator 27 shown in FIG. 3 (e) to decompose organic substances adhering as residues on the surface of the circuit board 1. By attaching a hydroxyl group (-OH) on the surface, the adhesion strength between the sealing body 4 formed in the next molding step and the circuit board 1 can be further increased.
[0022]
Next, FIG. 4F shows a sealing step. The circuit board 1 is placed on the fixing base 18 and fixed with the fixing frame 15. Then, the frame body 19 is placed on the fixed frame 15, and the sealing body 4 made of epoxy resin is embedded with the squeegee 17 so as to cover the mounted components 3 on the circuit board 1. The ground pattern 5 formed on the outer periphery of the circuit board 1 by the fixing frame 15 is not covered with the sealing body 4 and is formed to be smaller than the outer shape of the circuit board 1. The sealing body 4 is made of an epoxy resin, a filler having an average particle diameter of 100 μm or less, and a curing agent. Inorganic substances such as silica and aluminum hydroxide are used as the filler. As the curing agent, a curing agent such as an acid anhydride or an amine is selected and used according to the mechanical properties of the mounted component 3.
[0023]
The thickness of the frame 19 is set to be equal to or more than the height of the component having the highest height among the plurality of mounted components 3 +0.2 mm so as to cover the entire mounted component 3. This is because, when the sealing body 4 is supplied into the frame body 19, the central part is lower than the peripheral part in contact with the frame body 19, and a meniscus state is obtained.
[0024]
Therefore, in order to securely seal the mounted component 3 even in the center portion of the circuit board 1, it is necessary to design a frame 19 that is higher than the height of the mounted component 3 that is the highest from the circuit board 1 +0.2 mm or more. It becomes.
[0025]
When the mounting component 3 is sealed with the sealing body 4 usually made of epoxy resin, the epoxy resin is supplied in the plane direction after the epoxy resin is supplied. It is necessary to use an epoxy resin having a viscosity of from 1000 Pa · s to 1000 Pa · s.
[0026]
Then, after supplying the epoxy resin in order to fill the sealing body 4 made of the epoxy resin around the components without bubbles, the defoaming is performed in a vacuum chamber. Degassing is performed at a degree of vacuum of 1 Torr or less, so that bubbles trapped inside the epoxy resin can be defoamed due to the viscosity of the epoxy resin.
[0027]
Further, in order to eliminate air bubbles, not only the degree of vacuum is increased after the supply of the epoxy resin, but also the degassing is performed, and the epoxy resin is supplied in a vacuum chamber at a vacuum of 1 Torr or less before the supply of the epoxy resin.
[0028]
Thereafter, the degree of vacuum is increased to 100 Torr or more, and bubbles in the paste can be eliminated by a pressure difference from the initial degree of vacuum. By repeatedly increasing and decreasing the degree of vacuum in this manner, the number of bubbles can be further reduced.
[0029]
After the supply of the epoxy resin is completed, the sealing body 4 made of the epoxy resin is cured by leaving it in a furnace at 100 ° C. for 1 hour and further in a furnace at 150 ° C. for 3 hours. By performing the two-stage curing as described above, the curing of the sealing body 4 is gradually progressed, and the difference in thermal expansion coefficient between the sealing body 4 and the circuit board 1 and the internal stress due to the curing shrinkage of the sealing body 4 are alleviated. As a result, it is possible to reduce the warpage of the circuit board 1 and improve the reliability such as a heat cycle.
[0030]
Further, after the sealing body 4 is cured by leaving it in the above-mentioned furnace at 150 ° C. for 3 hours, it is cooled at a rate of 0.5 ° C./min or less. By thus gradually lowering the temperature, the warpage of the circuit board 1 can be further reduced.
[0031]
Next, as shown in FIG. 4 (g), a film 8 coated with a UV-curable adhesive is attached to the opposite surface of the circuit board 1 on which the sealing body 4 is formed. The UV-curable pressure-sensitive adhesive can lose its tackiness by irradiating ultraviolet light, and the circuit board 1 and the film 8 can be peeled freely. Alternatively, a thermosetting adhesive may be used. As the film 8, PET, PPS, or the like can be used.
[0032]
FIG. 4H shows a plating step. The metal film 2 is formed on the portion including the sealing pattern 4 on the circuit board 1 and the ground pattern 5 formed on the four outermost sides of the surface layer of the exposed circuit board 1.
[0033]
Thus, the metal film 2 is grounded to the ground pattern 5, whereby a shielding effect of the module component by the metal film 2 can be obtained.
[0034]
In the present embodiment, the metal film 2 is formed by a plating method.
[0035]
The surface of the sealing body 4 is nucleated with Pd, and copper plating is formed to a thickness of 0.5 μm by an electroless method. Further, copper plating is performed by an electrolytic method to form a dense 10 μm copper-plated metal film 2 on the surface of the sealing body 4.
[0036]
A film 8 with a UV adhesive is stuck on the opposite surface of the sealing body 4. The metal film 2 does not adhere to the surface of the circuit board 1 opposite to the sealing body 4 with the film 8 serving as a resist film.
[0037]
The feature of electroless plating and electrolytic plating is that in electroless plating, plating can be formed on an insulator, and a film can be formed uniformly on a portion where a plating solution is wet. However, there is a drawback in that the film formation speed is slow and it is difficult to form a thickness of 3 μm or more, and when the film thickness is large, the internal stress increases and the interface between the mold resin layer and the plating layer is easily peeled off. Therefore, high quality is ensured at low cost by combining electrolytic plating which can form a thick film at a high plating growth rate.
[0038]
By using this plating method, a ground pattern 5 and mounting components 3 formed on the outermost four sides of the surface layer of the circuit board 1 are formed in a sealing body 4 and connected to the metal film 2 to thereby provide the shielding effect shown in FIG. According to the examination graph, the case where the metal case is attached based on the state where the sealing body 4 is formed and the metal film 2 is not formed, the case where the ground pattern 5 is provided at the four corner portions of the circuit board 1 and the circuit board Compared to the case where the ground patterns 5 are provided on the four outermost sides of the circuit board 1, the provision of the ground patterns 5 on the four sides of the circuit board 1 can provide a more effective shielding effect than when a metal case is attached. For this reason, by connecting the ground pattern 5 and the metal film 2 at four sides rather than connecting the metal pattern 2 at several places, a more reliable shielding effect can be obtained.
[0039]
If the thickness of the metal film 2 is about 1 micron or more, a sufficient shielding effect is obtained. The metal film 2 is formed by forming a copper metal film 2 on the surface of the sealing body 4 by electroless plating, and then forming a copper metal film 2 on the surface by electrolytic plating to make the metal film 2 more dense. By doing so, the connection resistance with the ground pattern 5 is reduced and the ground potential of the metal film 2 formed on the sealing body 4 is stabilized, thereby enhancing the shielding effect.
[0040]
As a metal material, a good shielding effect can be obtained by lowering the conductor resistance of the metal film 2 with a material having high conductivity such as Cu or Ag. Conversely, a material with low conductivity, such as Ni, cannot provide an efficient shielding effect.
[0041]
As a method for forming a metal film on the surface of the sealing body 4, not only a plating method but also a method such as an evaporation method or a sputtering method may be used.
[0042]
Further, by forming a rust-proof layer on the surface of the metal film, the environmental resistance of the module component is improved. The rust prevention layer is formed by coating a resin coating material having a heat resistance temperature of 180 ° C. or higher. Further, a metal layer such as Sn or Ni may be formed by a plating method, a sputtering method, or the like.
[0043]
Next, by irradiating the film 8 adhered to the opposite surface of the sealing body 4 with ultraviolet light, the UV curable adhesive applied to the film 8 is cured, and the film 8 is peeled off from the circuit board 1 to remove the module component. Finalize.
[0044]
(Embodiment 2)
The method for manufacturing a module component according to the second embodiment of the present invention will be described for a case where a plurality of the module components described in the first embodiment are collectively manufactured.
[0045]
As shown in FIG. 6, an electrode 10 provided for mounting the mounting component 3 is formed on a surface of the integrated circuit board 6 in which a plurality of at least two single module substrates are connected into one. A ground pattern 5 is formed on the outer periphery of each module substrate.
[0046]
FIG. 7 shows a state where the lead-free solder 20 is supplied to the surface of the electrode 10. FIG. 8 shows a state where the mounted component 3 is mounted and mounted. The mounting steps shown in FIGS. 6 to 8 are the same as the mounting steps described in the first embodiment. FIG. 9 shows a sealing body 4 formed so as to cover the mounted components 3 mounted on the collective circuit board 6. FIG. 10 shows a state in which the cutting step has been performed.
[0047]
A sealing body 4 made of a coated epoxy resin is formed on a ground pattern 5 formed on the outermost four sides of the surface layer of each circuit board 1 of the collective circuit board 6. In order to remove the sealing body 4, the peripheral portion of the ground pattern 5 is cut into a lattice shape using a dicing saw 11, and the ground pattern 5 on each circuit board 1 is exposed. Regarding the exposure of the ground pattern 5, not only the whole pattern is exposed, but also a part of the pattern may be shaved to expose only the side end. At this time, not only a dicing saw but also a luter, a milling machine, a laser processing machine, or the like may be used. In this case, since the ground pattern 5 has a lattice shape, it can be processed even with a dicing saw or a milling machine. However, when the circuit board 1 having an irregular shape or the ground pattern 5 is not a straight line, a luter or a laser processing machine is preferable.
[0048]
Next, as shown in FIG. 11, the sealing body 4 on the collective circuit board 6 exposing a part of the peripheral portion of the grid-like ground pattern 5 and the outermost four sides of the surface layer of the exposed collective circuit board 6 The metal film 2 is formed in a portion including the ground pattern 5 formed in a lattice shape. Thus, the metal film 2 is grounded to the ground pattern 5, whereby a shielding effect of the module component by the metal film 2 can be obtained.
[0049]
Next, as shown in FIG. 12, the assembled circuit board 6 having the metal film 2 formed on the surface of the sealing body 4 is divided into individual module parts by using a dicing saw 11. At this time, by using a blade width B that is equal to or less than the blade width A of the dicing saw obtained by cutting the sealing body 4, the projected area of the sealing body 4 covered with the metal film 2 as shown in FIG. The projection area of the circuit board 1 is set to be larger, and a step is provided between the sealing body 4 and the circuit board 1.
[0050]
By providing this step, adhesion of the metal film 2 formed by electroless plating and electrolytic plating can be ensured, and peeling of the metal film 2 from the sealing body 4 and the ground pattern 5 can be prevented. As a result, the ground pattern 5 formed on the circuit board 1 and the metal film 2 provided on the sealing body 4 are securely connected, and the circuit composed of the mounting components 3 formed on the circuit board 1 is reliably shielded. it can.
[0051]
Although the Pb-free solder is used for the mounting portion in the present invention, a conductive paste in which a filler containing Ag as a main component is kneaded may be used. By using a conductive paste, mounting can be performed without using flux, and cleaning can be simplified.
[0052]
【The invention's effect】
As described above, according to the present invention, a mounting step of mounting a mounting component made of an electronic component on a circuit board on which a ground pattern is formed on the outermost periphery of a surface layer and mounting it with solder, and a circuit board mounting the mounting component A washing step of washing, a sealing step of forming a sealing body by filling an epoxy resin on the circuit board on which the mounted components are mounted, and forming a plating layer on the entire surface of the sealing body and the surface of the circuit board. By providing a module component manufacturing method including a plating process, it is possible to provide a module component capable of eliminating a gap between a circuit board and a metal film and performing reliable shielding.
[Brief description of the drawings]
FIG. 1 is a perspective view of a module component according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the module component according to the first embodiment of the present invention. FIG. (B) Cross-sectional view of solder supply to circuit board of the present invention (c) Cross-sectional view of mounting of mounted components on circuit board of the present invention (d) Cleaning process diagram of circuit board mounted with mounted components of the present invention (e) FIG. 4 (f) Sealing process diagram of module component of the present invention (g) Cross-sectional view of mounting of sealing body of the present invention (h) Plating treatment of module component of the present invention FIG. 5 is a cross-sectional view of the module component according to the first embodiment of the present invention. FIG. 6 is a perspective view of the composite circuit board according to the second embodiment of the present invention. FIG. 8 is a perspective view of a composite circuit board supplied with solder 2 according to a second embodiment of the present invention. FIG. 9 is a perspective view in which a sealing body is formed according to the second embodiment of the present invention. FIG. 10 is a cross-sectional view and a top view in which the sealing body according to the second embodiment of the present invention is diced. 11 is a cross-sectional view and a top view of the sealing body according to the second embodiment of the present invention after plating processing. Exploded perspective view of a conventional module part [Explanation of reference numerals]
DESCRIPTION OF SYMBOLS 1 Circuit board 2 Metal film 3 Mounting component 4 Sealing body 5 Ground pattern

Claims (5)

A mounting step of mounting a mounting component made of an electronic component on a circuit board on which a ground pattern is formed on the outermost periphery of the surface layer and mounting the component with solder, a cleaning step of cleaning the circuit board mounting the mounting component, and A method for manufacturing a module component, comprising: a sealing step of forming a sealing body by filling an epoxy resin on a mounted circuit board; and a plating step of forming a plating layer on the entire surface of the sealing body and the surface of the circuit board. . A mounting step of mounting a mounting component made of an electronic component on a circuit board having a ground pattern formed on the outermost periphery of a surface layer and mounting the component with solder, a cleaning step of cleaning the circuit board mounting the mounting component, and A sealing step of forming a sealing body by filling an epoxy resin on a mounted circuit board; a cutting step of cutting a part of the circuit board including the ground pattern from above the sealing body; From the plating step of forming a plating layer on the entire surface of the body and the surface of the circuit board exposed by cutting, and from the dividing step of cutting and dividing the collective board in which the mounted components are shielded by forming the plating layer for each single board Manufacturing method of modular parts. 3. The method for manufacturing a module component according to claim 1, wherein a plasma process for attaching a hydroxyl group to a surface of the circuit board is added before the sealing process. The method according to claim 1 or 2, wherein the resin is cured in two stages at different temperatures as a sealing step. 3. The method according to claim 1, wherein the plating step comprises a two-stage plating step of an electroplating step after the electroless plating step.

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