JP2003174258A - Electronic component and mounting structure thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component capable of securing a sufficient mounting area for an electronic component element, and capable of coping with the formation of a fine pattern or a microvia, rigid in the mounting strength on a mother board while being highly accurate and highly dense. <P>SOLUTION: In the electronic component 1 constituted of the electronic component element 3 formed on the upper surface of a print substrate 2 and a plurality of terminal electrodes 8 formed on the lower surface of the same, the lower surface of the print substrate 2 is constituted of the lower surface of the print substrate 2 or a first lower surface 80, a second lower surface 60 formed at a position higher than that of the first lower surface 80 in the direction of thickness of the same, and a slope 70 connecting the first lower surface 80 and the second lower surface 60 while the terminal electrode 8 is formed by continuing conductor films 6, 7 on at least the second lower surface 60 and the slope 70. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component using a printed circuit board mounted on an electronic device such as a portable electronic device, and more particularly to an electronic component mountable on a support substrate such as a motherboard.

[0002]

2. Description of the Related Art Conventional electronic components are shown, for example, in FIGS.
As shown in FIG. 5, the printed circuit board 50 on which the multilayer wiring pattern is formed by the stacking method and the build-up method, the electronic component element 53 mounted on the one main surface thereof, and the shield cover 5
4 and.

Here, a build-up board will be described as an example. The printed board 50 has a wiring pattern 55 and photosensitive resin layers 51a and 51c on both main surfaces of a core layer 51b which is an insulating board made of resin. It is formed by alternately stacking. An electrode 57 and a wiring pattern 58 are formed on the upper surface of the resin layer 51a, and the electronic component element 5 is formed thereon.
3 is mounted, and the shield cover 54 is mounted so as to cover the electronic component element 53.

Further, on the lower surface of the printed circuit board 51, a terminal electrode 56 used for mounting on a mother board (not shown, the same applies hereinafter) is formed.

When the electronic components are solder-mounted on the side surface of the printed circuit board 51, solder fillets are formed to ensure sufficient mounting strength. A plurality of semicircular grooves 59 formed in the direction are formed, and a side surface electrode 52 formed by depositing an electrode material on the inner periphery of the groove is formed.
It is connected to the terminal electrode 56. This side electrode 52 is
It is formed over the entire area from the lowermost insulating substrate 51c to the uppermost insulating substrate 51a.

When manufacturing the printed circuit board 51, the side surface electrode 52 is formed from the lowermost resin layer 51c to the uppermost part by a drill or the like at a desired position in the state of a multi-piece substrate (not shown) in which the printed circuit boards 51 are assembled. After forming a through hole that penetrates to the upper surface of the resin layer 51a, a via hole conductor is formed by a plating method. When divided into individual printed boards 51, the via-hole conductors are divided to form side surface electrodes 52 which are connected in a shape like a groove 58 from the lowermost layer 51c to the uppermost layer 51a.

Therefore, both ends of the uppermost insulating substrate 51a are formed with recessed portions 59a which are recessed inward, and as a result, electronic components mounted on the main surface of the uppermost insulating substrate 51a. The element 53 is mounted at a position avoiding the recess 59a.

[0008]

Conventional printed circuit board 5
In the electronic component using No. 1, as described above, the side surface electrode 52 is formed over the entire area from the lowermost insulating substrate 51c to the uppermost insulating substrate 51a. Therefore, on the main surface of the uppermost insulating substrate 51a, the mountable area of the electronic component element 53 is reduced due to the concave portion of the side electrode 52, and as a result, it is difficult to cope with the high functionality of the electronic component. Alternatively, there is a problem in that it is difficult to reduce the size because the formation of the wiring pattern 58 formed on the printed board 51 and the layout design of the electronic component element 53 are difficult. Further, the side electrode 52 is formed by forming recesses on both side surfaces of the side electrode 52 and forming a conductor on the inner circumference of the recess, but the process becomes complicated and a yield problem occurs.

On the other hand, in order to solve the above-mentioned problems, an electronic component in which the side electrode 52 is not formed is conceivable. However, when the solder is mounted on the mother board, the side electrode 52 by soldering
Since no fillet is formed on the substrate, the mounting strength of the electronic component is significantly reduced. In particular, in portable electronic devices and the like represented by mobile phones, which have recently become widespread, it is necessary to ensure sufficient drop strength in a mounted state, and thus it is not practically usable.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is to mount a terminal electrode of an electronic component to be joined to a mother board even if the electronic component is downsized and has high functionality. It is possible to secure the joint strength with the mother board and to make it easy to manufacture with high precision,
It is to provide an electronic component that can support a high-density design.

[0011]

An electronic component according to the present invention is an electronic component in which an electronic component element is mounted on the upper surface of a printed board and a plurality of terminal electrodes are formed on the lower surface, wherein the printed board is on the lower surface. A second lower surface formed at a position higher than the lower surface in the thickness direction of the printed circuit board, and an inclined surface connecting the lower surface of the printed circuit board and the second lower surface,
In addition, the terminal electrode is formed of a conductive film deposited from at least the second lower surface to the inclined surface.

Further, the electronic component of the present invention is characterized in that the terminal electrode is further led out from the inclined surface to a lower surface region of the printed board.

Further, in the electronic component of the present invention, the printed board is formed by sequentially laminating a wiring pattern and a photosensitive resin on the lower surface of an insulating substrate made of resin, and a conductive film formed on the second lower surface. Is the wiring pattern exposed by irradiating the lower surface of the printed circuit board with laser light to partially burn off the photosensitive resin.

Furthermore, the electronic component of the present invention is characterized in that the printed circuit board has a substantially rectangular shape, and the second lower surface is arranged at four corners of the printed circuit board.

The mounting structure of the electronic component of the present invention is
The electronic component described above is placed on a support substrate having a connection pad electrically connected to the terminal electrode,
It is characterized in that the terminal electrode and the connection pad are joined to each other via solder having an increased thickness in a region directly below the second lower surface.

[0016]

According to the present invention, the printed circuit board is provided on its lower surface with
It has a second lower surface formed at a position higher than the lower surface in the thickness direction of the printed circuit board, and an inclined surface connecting the lower surface of the printed circuit board and the second lower surface. The terminal electrode formed on the lower surface of the printed circuit board is formed of a conductor film deposited at least from the second lower surface to the inclined surface.

Therefore, since the conductor film is deposited from the second lower surface to the inclined surface, the area of the terminal electrode can be substantially increased, and the electronic component is solder-mounted on the supporting substrate such as a mother board. At this time, the solder enters the space formed from the upper surface of the support substrate and the second lower surface to the inclined surface,
Since the fillet in which the solder is sufficiently attached to the terminal electrode is formed, it is possible to secure the bonding strength between the electronic component and the support substrate. As a result, it can be used for a portable electronic device where drop strength in a mounted state is important.

Further, according to the present invention, when the electronic component is mounted on the support substrate, the fillet of the solder for connecting the two is formed only in the space formed from the second lower surface to the inclined surface. The entire upper surface can be used as a region for mounting the electronic component element, and the area for mounting the electronic component element on the upper surface can be expanded to enable higher functionality or miniaturization. Further, there is no restriction on the layout of the electronic component element, and the degree of freedom in design can be improved.

Further, according to the present invention, since the terminal electrode is led out from the inclined surface to the region of the lower surface of the printed board, the area where the solder is joined to the terminal electrode can be further increased, and the solder mounting can be performed. In the case of performing, the joint strength of the solder can be further increased.

Furthermore, according to the present invention, since the printed board in which the wiring pattern and the photosensitive resin are sequentially laminated on the lower surface of the resin-made insulating board is used, it is possible to form a high-precision and high-density fine pattern and micro vias. Can respond. Further, since the wiring pattern is exposed and the conductor film on the second lower surface is formed by burning away a part of the photosensitive resin by irradiating the lower surface of the printed circuit board with laser light, the step of forming the conductor film can be omitted. The manufacturing process is simplified.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The electronic component of the present invention will be described below in detail with reference to the drawings. 1 is an external perspective view of an electronic component 1 according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the electronic component 1 of the present invention, and FIG. 3 is a support substrate 20 for supporting the electronic component 1 of FIG.
It is sectional drawing which shows the state mounted above. The electronic component 1 shown in the figure is a build-up multilayer wiring printed circuit board (hereinafter, simply referred to as “printed circuit board”) formed in a substantially rectangular shape.
2), an electronic component element 3 mounted on the upper surface of the printed circuit board 2, and a shield cover 4.

The printed circuit board 2 has a wiring pattern 9 made of copper on both main surfaces of a core layer 2b which is an insulating substrate made of resin.
And the photosensitive resin layers 2a and 2c are alternately laminated to each other by a build-up method. As a material for such a core layer 2b, for example, a prepreg obtained by impregnating glass fiber, aramid fiber or the like with an epoxy resin is preferably used.

On the upper surface of the printed circuit board 2, wiring patterns 12 and 13 made of copper and electrodes 10 for mounting the electronic component element 3 are attached and formed, respectively. At this time, the wiring pattern 1 between the insulating substrates 2a, 2b, 2c
Connection between 2, 13 and the like is performed by irradiating a laser beam from the upper surface or the lower surface of the printed circuit board 2 and forming a via hole in the opening portion opened by the irradiation by using a conventionally known plating treatment method. Be seen.

The printed circuit board 2 has a plurality of electronic component elements 3 mounted on the electrodes 10 formed on the upper surface of the printed circuit board 2. The mounting area extends over substantially the entire upper surface of the printed circuit board 2. Further, the lower surface 5 of the printed circuit board 2 has the first
A lower surface 80, a second lower surface 60 formed at a position higher in the thickness direction than the first lower surface 80, and an inclined surface 70 connecting the first lower surface 80 and the second lower surface 60, Of the lower surface 5, the conductor films 6 and 7 are continuously formed on the second lower surface 60 and the inclined surface 70 to form the terminal electrode 8. Further, such a conductor film may be formed such that one end side thereof extends to the first lower surface 80. In that case, the conductor films 6, 7, 8a formed continuously
One terminal electrode 8 is formed.

The inclined surface 70 is formed so as to be gently inclined toward the center of the lower surface 5 of the printed board 2. By forming the inclined surface 70 in this way, the terminal electrode 8 can be easily formed by plating or the like,
In addition, it is possible to secure a wide area for forming the terminal electrode 8. Four such terminal electrodes 8 are provided, one at each of the four corners of the lower surface of the printed board, and these terminal electrodes 8 are connected to the corresponding connection pads 21 provided on the support substrate 20 such as a mother board. The electronic component 2 is attached and mounted on the support substrate 20 by soldering.

Thus, the second lower surface 6 of the printed circuit board 2
Since the conductor films 6 and 7 are adhered and formed from 0 to the inclined surface 70, a large area of the terminal electrode 8 can be substantially secured, and the electronic component 1 is soldered onto the supporting substrate 20 such as a mother board. When mounting, the connection pad 21 on the upper surface of the support substrate
And, the solder 30 can satisfactorily enter into the area surrounded by the second lower surface 60 and the inclined surface 70, and a wide solder joint area can be secured, and a sufficient amount of solder can be provided between the terminal electrode 8 and the support substrate 20. Since the solder fillet 30 is formed, the bonding strength between the electronic component 1 and the support substrate 20 can be improved. This makes it suitable for use in a portable electronic device in which the drop strength in the mounted state is important.

The fillet of the solder 30 described above is
It is formed only in the region below the second lower surface 60 and the inclined surface 70, and the entire upper surface of the printed board 2 can be used for mounting the electronic component element 3. Therefore, it becomes possible to mount a larger number of electronic component elements 3 on the printed circuit board 2 to enhance the functionality of the electronic component 1 and to downsize the entire structure of the electronic component 1. There are also advantages that the restrictions on the layout of the electronic component element 3 are reduced and the degree of freedom in design is increased.

A chip-type capacitor, a chip-type resistor, a chip-type coil or the like is used as the electronic component element 3, and the electronic component element 3 is placed at a predetermined position on the upper surface of the printed board and soldered. It is electrically and mechanically connected to the printed circuit board 2 by joining with a conductive adhesive material such as.

On the other hand, the shield cover 4 is made of metal such as Kovar, and in the present embodiment, it covers all the electronic component elements 3 arranged on the upper surface of the printed board 2. It is mounted on the printed circuit board 2. The shield cover 4 serves to prevent noise from entering the electronic component element 3 and wiring in the printed circuit board 2 by electromagnetically shielding noise from the outside, and conventionally known sheet metal working and narrowing down. The shield cover 4 which is formed into a predetermined shape by adopting processing or the like is provided on the upper surface of the electronic component element 3 disposed substantially in the center of the upper surface of the printed circuit board with an adhesive such as solder or epoxy resin interposed therebetween. It is attached to the printed board 2 by being adhered and fixed.

When the electronic component 1 is used, such a shield cover 4 may be electrically floated without being connected to the ground potential, but in order to make the above-described shield action more reliable. Is preferably kept at the ground potential via the electronic component 3 and the printed circuit board 2.

The electronic component 1 described above has the terminal electrode 8
The terminal electrode 8 and the connection pad 8 are mounted on predetermined positions on the supporting substrate 20 having a plurality of connection pads 21 corresponding to each other, and the thickness of the terminal electrode 8 and the connection pad 8 is increased in a region immediately below the second lower surface. Support substrate 20 by bonding via solder 22
Mounted on.

Next, a method of manufacturing the above-mentioned electronic component 1 will be described. First, the terminal electrodes 8 are formed on the printed board 2 formed by the build-up method. That is, in the state of a multi-piece board (not shown) in which the printed boards 2 are assembled, laser is irradiated from the photosensitive resin layer 5c side to the positions corresponding to the four corners of the printed board 2. There are excimer laser, carbon dioxide gas laser, YAG laser, etc. as the light source of the laser light. Depending on the selection and conditions of the laser light source, the laser light forms a notch for the via hole, but the upper surface of the core layer 2b. When the wiring pattern 9 made of copper is reached, the photosensitive resin layer 5c does not exist on the surface of the wiring pattern 9 and cannot penetrate further. Therefore,
The copper wiring pattern 9 is exposed, and the exposed surface becomes the conductor film 6. Then, the conductor films 7 and 8a are formed on the inclined surface 70 by plating and photoetching, and the terminal film 8 is formed by connecting the conductor film 6 and the conductor films 7 and 8a.

Next, the electrode 10 for mounting the electronic component element 3 and the wiring pattern 12 are adhered to the upper surface of the printed board 2, and the electronic component element 3 is mounted by a method such as flip chip or solder reflow. After that, shield cover 4
Are joined to complete the mounting of the electronic component element 3. afterwards,
The electronic component 1 is obtained by dividing the multi-piece printed wiring board into individual electronic components 1 by a method such as dicing.

The present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the gist of the present invention.

For example, in the above embodiment, the second
The lower surface 60 is located at the four corners of the lower surface of the printed circuit board, and the inclined surface 70 and the first lower surface 80 are arranged inside thereof, but instead of this, as shown in FIG. It is also possible to position the first lower surface 80 'and dispose the inclined surface 70' and the second lower surface 60 'inside thereof. In this case, the terminal electrode 8'is continuously formed over the first lower surface 80 ', the inclined surface 70', and the second lower surface 60 '. Even when such an electronic component is mounted on the supporting substrate, the second lower surface is also formed. Since the thickness of the solder can be increased in the region directly below 60 'and a sufficient bonding area and the amount of solder can be secured, the electronic component is firmly attached and mounted on the support substrate.

In addition, in the above-described embodiment, if the side surface of the electronic component element 3 and the side surface of the printed circuit board 2 are covered with the shield cover 4 by bending the outer peripheral portion of the shield cover 4 downward, for example, The shield effect of 4 can be effectively enhanced.

[0037]

According to the configuration of the present invention, even if the electronic component is downsized and has high functionality, it is possible to secure a sufficient bonding area of the terminal electrode of the electronic component to be bonded to the mother board, and to bond it to the mother board. It is possible to provide an electronic component having high strength.

Further, even if the size is reduced, the concave side surface electrode formed on the side surface of the printed circuit board as in the prior art can be omitted, so that the mountable area of the electronic component element is expanded and the electronic component element can be mounted. The degree of freedom in design can be improved.

Further, it is formed by a so-called build-up method in which an internal wiring pattern and a photosensitive resin are sequentially laminated on both main surfaces of an insulating substrate made of resin, and a fine pattern of high-precision and high-density wiring and a micro pattern are formed. It is possible to provide an electronic component corresponding to the formation of vias, and at the same time, the lower surface of the printed circuit board is irradiated with laser light to burn off the photosensitive resin to expose the wiring pattern and form the conductor film on the second lower surface. It is possible to provide an electronic component in which the step of forming a film can be omitted, the manufacturing process is simplified, and the yield is improved.

[Brief description of drawings]

FIG. 1 is an external perspective view of an electronic component according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the electronic component shown in FIG.

3 is a cross-sectional view showing a state where the electronic component 1 of FIG. 1 is mounted on a support substrate 20. FIG.

FIG. 4 is a sectional view of an electronic component according to another embodiment of the present invention.

FIG. 5 is an external perspective view of a conventional electronic component.

FIG. 6 is a cross-sectional view of a conventional electronic component.

[Explanation of symbols]

1 ... Electronic parts 2 ... Printed circuit board 3 ... Electronic component element 4 ... Shield cover 60, 60 '... second lower surface 6 ... Conductor film 70, 70 '... Inclined surface 7 ... Conductor film 80, 80 '... the first lower surface 8a ... Conductor film 8, 8 '... Terminal electrode 9 ... Wiring pattern 20 ... Support substrate 21 ... Connection pad 22 ... Solder

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5E317 AA04 BB02 BB12 CC31 CD32                       CD34 GG07 GG16                 5E344 AA01 AA22 BB02 BB06 BB10                       CC23 DD02 EE12 EE26                 5E346 AA12 AA15 AA43 BB16 CC04                       CC05 CC09 CC32 EE33 FF04                       GG15 GG17 GG22 GG25 HH22                       HH25 HH33

Claims (5)

[Claims] 1. An electronic component in which an electronic component element is mounted on the upper surface of a printed circuit board and a plurality of terminal electrodes are formed on the lower surface, wherein the printed circuit board is on the lower surface in the thickness direction of the printed circuit board rather than the lower surface. It has a second lower surface formed at a higher position and an inclined surface connecting the lower surface of the printed board and the second lower surface, and the terminal electrode is adhered at least from the second lower surface to the inclined surface. An electronic component, which is formed of a conductor film. 2. The electronic component according to claim 1, wherein the terminal electrode is further led out from the inclined surface to a lower surface region of the printed circuit board. 3. The printed board is formed by sequentially laminating a wiring pattern and a photosensitive resin on a lower surface of a resin insulating board, and the conductor film formed on the second lower surface is a lower surface of the printed board. An electronic component, wherein the wiring pattern is exposed by burning off a part of the photosensitive resin by laser irradiation. 4. The printed circuit board according to claim 1, wherein the printed circuit board has a substantially rectangular shape, and the second lower surface is arranged at four corners of the printed circuit board. Electronic components. 5. The electronic component according to claim 4 is placed on a support substrate having a connection pad electrically connected to the terminal electrode, and the terminal electrode and the connection pad are provided on a second substrate. A mounting structure for electronic components that is bonded via solder with an increased thickness in the region directly below the lower surface.