JP2006012943A - Electronic device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an electronic device having excellent reliability which can suppress the continuity failure of a surface mounting part even if a crack or peeling occurs in a sheathing resin, and to provide a method of manufacturing the electronic device which can easily manufacture the electronic device and which has excellent mass productivity and easy lowering of the back of packaging. <P>SOLUTION: After chip type electronic parts 1a-1c are surface mounted on a circuit substrate 3 (a), a sheet-like resin material 9 having high viscosity and thixotropy property is placed on the upper surface of the electronic parts 1a-1c (b), then, the peripheral edge of the resin material 9 is pressurized/heated by a frame type hot plate press 10, and the resin material 9 is deformed. And, the resin material 9 is hot press bonded to the circuit substrate 3 so that hollow parts 6a-6d are formed. Thereafter, a curing treatment is performed, and a coating resin 5 is formed (c). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic device and a method for manufacturing the electronic device, and more particularly, an electronic component including at least one chip-type electronic component such as a ceramic capacitor or an inductor having external electrodes formed at both ends is mounted on a circuit board. And packaged electronic device and a method of manufacturing the same.

  In recent years, when an electronic device in which a plurality of electronic components are mounted on a circuit board such as a printed circuit board is mounted on a device board, a solder reflow furnace has been widely used from the viewpoint of improving mounting efficiency.

  In the soldering method using this solder reflow furnace, after printing the solder cream on the device substrate, the electronic device is mounted on the printed pattern and heated at a high temperature to join the electronic device to the device substrate.

  By the way, when an electronic device is mounted on a device board using a solder reflow furnace, the entire electronic component on the circuit board is usually made of resin from the viewpoint of protecting the electronic component which is a surface-mounted component and ensuring good mountability. Covered with material.

  However, even if the electronic component is coated with a resin material in this way, the solder that joins the electronic component and the circuit board expands due to a reflow process at a high temperature, causing cracks in the coating resin, There is a risk of peeling from the circuit board, and adjacent electronic components and external electrodes are electrically connected via molten solder, which may cause a conduction failure such as a short circuit.

  Therefore, conventionally, as shown in FIG. 10, the mounting component 102 is covered with the resin film 101, and the lower end portion of the mounting component 102 is in contact with the component mounting solder 103 soldering the mounting component 102 to the upper end portion. Has proposed a hybrid IC provided with a solder withdrawal hole 104 that opens on the surface of the resin film 101 (Patent Document 1).

  The hybrid IC shown in FIG. 10 covers the hybrid substrate 105 with the resin film 101 by pouring a resin onto the hybrid substrate 105 with the tip of the pin in contact with the surface of the component mounting solder 103 from above. After the resin is cured, the pin is pulled out, thereby forming the solder escape hole 104.

  Further, in Patent Document 1, as shown in FIG. 11, a hybrid IC in which a gap 106 for retreating solder is selectively provided between a component mounting solder 103 for soldering a mounting component 102 and a resin film 101. Has also been proposed.

  In the hybrid IC of FIG. 11, after the resin is poured onto the hybrid substrate 105 and the hybrid substrate 105 is covered with the resin film 101, the hybrid substrate 105 is brought to a temperature in the vicinity of the solder melting point at which the solder can maintain a solid state. The resin film 101 is solidified in a heated state, and then the hybrid substrate 105 is returned to room temperature to selectively form a gap 106 for retracting the solder.

  Further, as shown in FIG. 12, the electronic device having a hollow structure has a hollow structure in which an IC component 113 mounted on a ceramic substrate 112 is covered with a resin case 114 via a solder 111, and the resin case 114 is bonded. There has been proposed a hybrid integrated circuit device in which a resin case 114 is adhered to a ceramic substrate 112 and a resin case 114 is covered with an exterior resin 116 (Patent Document 2).

JP-A-7-161873 JP-A-3-21756

  However, in the hybrid IC of FIG. 10 disclosed in Patent Document 1, as described above, the resin is dropped from above and covered with the component mounting solder 103 in a state of contacting the pins, and then the pins are pulled out. Since the solder escape hole 104 is formed, the manufacturing process of the solder escape hole 104 is complicated and the productivity is insufficient.

  In the hybrid IC of FIG. 11, only the gap 106 is selectively formed between the mounting solder 103 and the resin film 101 by changing the temperature, and it is difficult to manage the gap volume and the number of gaps. There was a problem that there was.

  In Patent Document 2, since the IC component 113 is covered with the resin case 114, when a plurality of IC components 113 having different heights are mounted on the circuit board 112, the IC component having the maximum height is supported. Therefore, the size of the resin case 114 must be selected, and a marginal space must be secured in consideration of variations in the height of IC components and variations in the resin case. That is, in Patent Document 2, when a plurality of IC components 113 having different heights or different heights are mounted on the circuit board 112, an extra space is formed in the electronic device, and the packaged There was a problem that the size of the apparatus was increased.

  The present invention has been made in view of such circumstances, and an electronic device having excellent reliability capable of suppressing poor conduction of a surface-mounted component without causing cracks or peeling in the exterior resin, and the An object of the present invention is to provide a method for manufacturing an electronic device that can easily manufacture an electronic device, is excellent in mass productivity, and can easily reduce the height of packaging.

  In order to achieve the above object, an electronic device according to the present invention includes a plurality of electronic components including at least one electronic component having external electrodes formed at both ends, mounted on a circuit board and packaged with a covering member. In the electronic device, the covering member is formed of a resin material having high viscosity and thixotropy so as to have a hollow portion around each electronic component.

  In the electronic device of the present invention, the electronic component is joined to the circuit board via solder, and the hollow portion is controlled to be larger than at least the total thermal expansion amount of the external electrode and the solder. It is characterized by being.

  Furthermore, the electronic device of the present invention is characterized in that at least one of the electronic components is partially embedded in the covering member.

  In addition, the electronic device manufacturing method according to the present invention has high viscosity and thixotropy after mounting a plurality of electronic components including at least one electronic component having external electrodes formed at both ends on a circuit board. A sheet-shaped resin material is placed on the upper surface of the electronic component, the outer peripheral portion of the resin material is heated to melt and deform the outer peripheral portion of the resin material, and a hollow portion is formed around each electronic component. As described above, the resin material and the peripheral portion of the circuit board are thermocompression bonded to cover the electronic component, and then the resin material is cured.

  The electronic device manufacturing method according to the present invention also includes a method of mounting a plurality of electronic components having different heights including at least one electronic component having external electrodes formed at both ends on a circuit board, and then providing a high viscosity and thixotropy. A sheet-like resin material having a property is placed horizontally on the upper surface of a tall electronic component among the electronic components, and the resin material is entirely heated and melted, so that at least the tall electronic component A part is embedded in the resin material, and the resin material and the peripheral portion of the circuit board are thermocompression-bonded so that a hollow portion is formed around each electronic component, and the electronic component is packaged, Thereafter, the resin material is cured.

  According to the electronic device of the present invention, in the electronic device in which a plurality of electronic components including at least one electronic component having external electrodes formed at both ends are mounted on a circuit board and covered with a covering member, Since the member is formed of a resin material having high viscosity and thixotropy so as to have a hollow portion around each electronic component, the external electrode and solder of the electronic component are thermally expanded by heating during the reflow process. However, it is possible to prevent the solder from pressing the coating resin, thereby preventing the coating resin from cracking and preventing the coating resin from peeling off from the circuit board.

  Moreover, it is possible to prevent adjacent electronic components and external electrodes of each electronic component from being short-circuited by the remelted solder, thereby suppressing the occurrence of poor conduction.

  In addition, the electronic component is joined to the circuit board via solder, and the hollow portion is controlled to be larger than at least the total thermal expansion amount of the external electrode and the solder. Even if the solder is thermally expanded, it does not come into contact with the coating resin, and the above-described effects can be reliably obtained.

  Furthermore, in the electronic device according to the present invention, at least one of the plurality of electronic components is partially embedded in the resin material, so that the height is different or the height varies. Even when certain electronic components are mixed and mounted on a circuit board, the height of the electronic device can be reduced.

  Further, according to the method for manufacturing an electronic device of the present invention, even if the sheet-like resin material is deformed so as to be joined to the circuit board, the resin material has thixotropic properties, so that only temporarily at the time of deformation. The viscosity is lowered and the fluidity is increased, whereby the mechanical strength can be maintained. Since the original high viscosity is restored after the deformation, the fluidity is lowered, and a hollow portion can be easily formed between the electronic component disposed on the peripheral portion of the circuit board and the resin material. And since only the peripheral part of a sheet-like resin material is heat-deformed and the desired hollow part is formed, a manufacturing process is simple, it can manufacture at low cost, and it is excellent also in mass-productivity.

  In addition, according to the method for manufacturing an electronic device of the present invention, even when a plurality of electronic components having different heights are mounted on a circuit board, a sheet-like resin material having high viscosity and thixotropy is entirely formed. By heating to high, an electronic component with a high height can be easily embedded in the resin material, and an electronic device with a reduced height can be easily manufactured.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an embodiment of an electronic device according to the present invention. The electronic device includes a plurality of electronic components 1 (1a to 1c) as surface mounting components, and electrodes of a circuit board 3. Resin material having high viscosity and thixotropy so as to be mounted on pads 4 (4a to 4f) via solder 2 (2a to 2f) and to have hollow portions 6a to 6d around electronic components 1a to 1c The coating resin 5 (coating member) is formed.

  The electronic component 1 is composed of, for example, a chip-type ceramic capacitor or inductor, and external electrodes 8 are formed at both ends of a component body 7 made of a ceramic sintered body as shown in FIG.

  Wiring is formed on the circuit board 3. The material of the circuit board 3 is not particularly limited as long as it has heat resistance capable of withstanding the reflow treatment. For example, ceramic materials, phenol resins, epoxy resins, polyimide resins, cyanate resins, polyphenylene ethers, etc. These organic resin materials are preferably used.

  In addition, since the resin material is thermally deformed by thermocompression bonding to form the coating resin 5, and it is necessary to form the hollow portions 6a and 6d between the coating resin 5 and the electronic components 1a and 1c, It must have thixotropic properties.

  Here, the thixotropic property means a property that when the resin material is deformed, the apparent viscosity is temporarily lowered by shearing, but thereafter the original highly viscous state is recovered. Therefore, since the resin material has thixotropy, only when the resin material is deformed to be joined to the circuit board 3, the apparent viscosity is temporarily reduced to increase the fluidity, and the pressurized peripheral edge is increased. The resin part is bonded to the substrate at the part, but deformation of the resin part that is not pressurized is small.

  And after deformation | transformation, the original highly viscous state will be recovered, fluidity | liquidity will fall, and this will not spread and spread resin material, but the coating | cover which has desired hollow part 6a-6d between electronic components 1a-1c Resin 5 can be formed.

  As a resin material having such a high viscosity and thixotropy, in the case of a thermosetting resin, for example, an epoxy resin (such as “HT-X20” manufactured by Hitachi Chemical Co., Ltd.) can be used. In this case, for example, a polyimide resin, a polyamide resin, or a polyimide amide resin can be used.

  Further, in the present embodiment, the hollow portions 6a to 6d are controlled to be larger than the total thermal expansion amount due to the heating of the external electrode 8 and the solder 2 by adjusting the heating conditions and the like. Thus, it is possible to avoid contact of the side surface portion of the solder 2 with the coating resin 5.

  As described above, in the present embodiment, the hollow portions 6a to 6d are formed around the electronic components 1a to 1c, and in particular, the hollow portions 6a and 6d are also formed between the covering member 5 and the electronic components 1a and 1c. Therefore, during the solder reflow process or the like, even if the external electrodes 8 and the solder 2 of the electronic components 1a to 1c are thermally expanded, the solder 2 does not press the coating resin 5, and therefore the coating resin 5 is cracked. The coating resin 5 can be prevented from peeling off from the circuit board 3. Moreover, it can prevent that the adjacent electronic components 1a-1c and the external electrodes 8 of each electronic component 1a-1c short-circuit with the remelted solder, and can suppress generation | occurrence | production of a conduction defect.

  Next, a method for manufacturing the electronic device will be described in detail.

  FIG. 3 is a cross-sectional view showing the manufacturing procedure of the method for manufacturing the electronic device.

  First, as shown in FIG. 3A, electronic components 1a to 1c having predetermined external dimensions (for example, length 1.0, width 0.5 mm, height 0.5 mm) are transferred to electrode pads 4a to 4c on the circuit board 3. The electronic components 1a to 1c are mounted on the circuit board 3 by being electrically connected to 4f via solders 2a to 2f.

  Next, as shown in FIG. 3B, a sheet-shaped resin material 9 having a predetermined thickness (for example, 0.25 mm) is placed on the upper surfaces of the electronic components 1a to 1c. Here, as the sheet-shaped resin material 9, as described above, a thermosetting resin material or a thermoplastic resin material having high viscosity and thixotropy is used.

  Next, as shown in FIG. 3C, the peripheral portion of the sheet-shaped resin material 9 is pressed for a predetermined time (for example, 15 minutes) with a frame type hot plate press 10 heated to a predetermined temperature (for example, 150 ° C.). Then, the resin material 9 is melted and thermocompression bonded to the circuit board 3 to bond the resin material 9 to the circuit board 3. And since the resin material 9 has thixotropy, when the peripheral part of the resin material 9 is pressurized with the frame type hot plate press 10 and deformed in an inclined shape, the viscosity temporarily decreases and the fluidity is reduced. The resin material 9 is thermocompression-bonded to the circuit board 3 with sufficient mechanical strength. Thereafter, the highly viscous state is recovered, and the resin material 9 is not spread and spreads to form the hollow portions 6a to 6d between the electronic components 1a to 1c. Next, the frame-type hot plate press 10 is removed, put into an oven heated to a predetermined temperature (for example, a temperature of 150 ° C.) and held for a predetermined time (for example, 3 hours), and the resin material 9 is completely cured. Thus, an electronic device covered with the coating resin 5 is manufactured.

  In addition, it is preferable that the frame-type hot plate press 10 is subjected to mold release treatment with a fluororesin or the like on the contact surface with the resin material 9 so that it can be used repeatedly.

  Thus, according to this manufacturing method, since the electronic components 1a to 1c are covered with the covering resin 5 so as to have the desired hollow portions 6a to 6d without impairing the mechanical strength, the electronic device is reflowed. When processing and mounting on the device substrate, it is possible to avoid cracks in the coating resin 5 and peeling between the circuit board 3 and the coating resin 5 even if the external electrodes 8 and the solder 2 are thermally expanded. In addition, it is possible to prevent the adjacent electronic components and the external electrodes 8 of the electronic components from being electrically connected by the remelted solder during reflow and causing a conduction failure such as a short circuit.

  In addition, the hollow portions 6a to 6d are formed around the electronic components 1a to 1c only by heating and pressurizing the peripheral portion of the resin material 9 with the frame-type hot press 10, and thus the manufacturing process is simple, The device can be manufactured at low cost and is excellent in mass productivity.

  FIG. 4 is a cross-sectional view showing a second embodiment of the present invention. This second embodiment shows a case where a large number of electronic devices are manufactured at one time.

  That is, in the second embodiment, a large number of electronic components 1 are surface-mounted on a large circuit board 11 and thermocompression bonded to the circuit board 11 via a large frame hot plate press 13. It is covered with a coating resin 12.

  The electronic device according to the second embodiment is manufactured as follows.

  That is, a sheet-like resin material is placed on the surface-mounted electronic component 1, and a predetermined portion of the resin material is heated and pressurized from above by a large frame-type hot plate press 13 to deform the resin material. The circuit board 11 and the resin material are thermocompression-bonded so that the hollow portions 14a to 14l are formed around the electronic components 1a to 1i, and then, as in the first embodiment, thermosetting treatment is performed, Thereby, the coating resin 12 is formed. Then, a large number of electronic devices can be obtained from the large-sized circuit board 11 by cutting the thermocompression-bonded portion vertically and horizontally with a cutting machine.

  As described above, in the second embodiment, a large number of electronic devices can be manufactured from the large-sized circuit board 11 at a time, and the mass productivity can be further improved.

  FIG. 5 is a cross-sectional view showing the third embodiment of the present invention. In the third embodiment, the low-profile electronic components 16a and 16c and the tall electronic component 16b are circuit boards 15. Are mounted on the surface, hollow portions 18a to 18d are formed around the electronic components 16a to 16c, and a part (upper part) of the tall electronic component 16b is embedded in the resin coating 17. .

  FIG. 6 is a sectional view of the manufacturing procedure showing the manufacturing method of the third embodiment.

  First, as shown in FIG. 6A, the low-profile electronic components 16a and 16c and the tall electronic component 16b are electrically connected to electrode pads 19a to 19f on the circuit board 15 via solders 20a to 20f. The electronic components 16 a to 16 c are connected and mounted on the circuit board 15.

  Next, as shown in FIG. 6B, a sheet-like resin material 21 having a predetermined thickness and high viscosity and thixotropy is placed on the upper surface of the tall electronic component 16b.

  Next, as shown in FIG. 6C, the box-type hot plate press 22 is heated to a predetermined temperature and pressurized from above to deform the resin material 21, and the upper part of the tall electronic component 16 b is placed on the resin material 21. The resin material 21 is thermocompression-bonded to the circuit board 15 so as to have the hollow portion 18 and is then placed in an oven heated to a predetermined temperature and held for a predetermined time. By curing, the coating resin 17 is formed, whereby an electronic device in which the hollow portions 18a to 18d are formed around the electronic components 16a to 16c is manufactured.

  As described above, when the electronic device has the electronic components 16a to 16c having different heights or variations, the resin material 21 is entirely heated and pressurized by the box-shaped hot plate press 22 to increase the height. By embedding the upper part of the electronic component 16b in the coating resin 17, the height of the electronic device can be reduced.

  FIG. 7 is a cross-sectional view showing a fourth embodiment of the present invention. In the fourth embodiment, electronic components 1a to 1c are formed on the upper surface of the circuit board 23, as in the first embodiment. In addition to being mounted, it is packaged with a coating resin 5 so as to form a hollow portion 6, and a semiconductor 24 is mounted in a lower surface recess of the circuit board 23, and the semiconductor 24 is covered with a resin material 25. .

  Thus, even when the electronic component such as the semiconductor 24 is built in the lower surface side of the circuit board 23, the electronic component 1a to the electronic component 1a to the solder reflow process are performed as in the first to third embodiments. Even if the external electrode 8 of 1c and the solder 2 are thermally expanded, the solder 2 does not press the coating resin 5, and therefore, the coating resin 5 is prevented from cracking or peeling from the circuit board 3. Moreover, it is possible to prevent the adjacent electronic components 1a to 1c and the external electrodes 8 of the electronic components 1a to 1c from being short-circuited by the remelted solder, thereby suppressing the occurrence of poor conduction. be able to.

  FIG. 8 is a sectional view showing a fifth embodiment of the present invention. In the fifth embodiment, a semiconductor 26 is surface-mounted on a circuit board 27 in addition to the chip-type electronic components 1a and 1b. Further, the chip type electronic component 1a and the semiconductor 26 are covered with a coating resin 28 so as to have hollow portions 6a to 6c and 6d '.

  Thus, even when the surface-mounted component includes a chip-type electronic component and an electronic component other than a chip-type electronic component such as a semiconductor, the same operational effects as those of the first embodiment can be obtained.

  In the fifth embodiment, the semiconductor 26 is surface-mounted on the circuit board 27 together with the chip electronic components 1a and 1b. However, it is sufficient that at least one chip electronic component is included. The present invention can be similarly applied to a case in which an electronic component such as a surface wave filter is included in part.

  FIG. 9 is a cross-sectional view of the sixth embodiment of the present invention. In the sixth embodiment, the electronic components 29a to 29c are surface-mounted on the circuit board 30, and the covering member 31 and the electronic component are mounted. A thin plate 32 is interposed between 29a and 29c.

  In the sixth embodiment, a resin material is supplied from above the thin plate 32 of the electronic components 29a to 29c surface-mounted on the circuit board 30 so that the hollow portions 33a to 33d are formed around the electronic components. Thus, the resin material is cured to form the coating resin 31.

  The present invention is not limited to the above embodiment.

  In addition, the present invention is particularly effective for small surface-mount components that are likely to cause poor conduction due to solder remelting after reflow processing.

1 is a cross-sectional view showing an embodiment (first embodiment) of an electronic device according to the present invention. It is sectional drawing of the electronic component mounted in the said electronic device. It is sectional drawing which shows the manufacturing procedure of 1st Embodiment. It is sectional drawing which shows 2nd Embodiment of the electronic device which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the electronic device which concerns on this invention. It is sectional drawing which shows the manufacture procedure of 3rd Embodiment. It is sectional drawing which shows 4th Embodiment of the electronic device which concerns on this invention. It is sectional drawing which shows 5th Embodiment of the electronic device which concerns on this invention. It is sectional drawing which shows 6th Embodiment of the electronic device which concerns on this invention. It is sectional drawing which shows an example of the background art described in patent document 1. FIG. It is sectional drawing which shows the other example of the background art described in patent document 1. FIG. It is sectional drawing which shows an example of the background art described in patent document 2. FIG.

Explanation of symbols

1a to 1c Electronic component 3 Circuit board 5 Coating resin (coating member)
6 Hollow part 8 External electrode 11 Circuit board 12 Coating resin (coating member)
14 hollow part 15 circuit boards 16a-16c electronic component 17 coating resin (coating member)
18 Hollow part 23a-23c Electronic component 27 Circuit board 28 Coating resin (coating member)
30 Circuit board 31 Coating resin (coating material)

Claims (5)

In an electronic device in which a plurality of electronic components including at least one electronic component having external electrodes formed on both ends are mounted on a circuit board and covered with a covering member,
The electronic device according to claim 1, wherein the covering member is formed of a resin material having high viscosity and thixotropy so as to have a hollow portion around each electronic component.   The electrode terminal of the electronic component is joined to the circuit board via solder, and the hollow portion is controlled to be larger than at least the total thermal expansion amount of the electrode terminal and the solder. The electronic device according to claim 1.   3. The electronic device according to claim 1, wherein at least one of the plurality of electronic components is partially embedded in the covering member.   After mounting a plurality of electronic components including at least one electronic component having external electrodes formed on both ends on a circuit board, a sheet-like resin material having high viscosity and thixotropy is placed on the upper surface of the electronic component. And the outer periphery of the resin material is heated to melt and deform the outer periphery of the resin material so that a hollow portion is formed around each electronic component. A method of manufacturing an electronic device, comprising: heat-compressing a portion to coat the electronic component; and thereafter curing the resin material.   After mounting a plurality of electronic components having different heights including at least one electronic component having external electrodes formed at both ends on a circuit board, a sheet-like resin material having high viscosity and thixotropy is used as the electronic component. Placed horizontally on the upper surface of the tall electronic component, the resin material is heated and melted as a whole, and at least a part of the tall electronic component is embedded in the resin material, The resin material and a peripheral portion of the circuit board are thermocompression bonded so that a hollow portion is formed around each electronic component, and the electronic component is packaged, and then the resin material is cured. A method for manufacturing an electronic device.

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