JPH09130031A - Mounting of electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form the shape of a bump to a drum type from a column type to improve connection reliability of the connecting portion by preventing crushing of excessive bump of solder bump to control the height of bump. SOLUTION: In the mounting structure depending on the method where an electronic part 1 is mounted on the mounting substrate 2 via the solder bump 6 provided on the electronic part 1, an electronic part 1 of the surface mounting type, a printed circuit board 2 for mounting the electronic part 1 and a chip type part 3 provided to the electronic part 1 are comprised and the solder bump 6 which is to be fused and crushed by the weight of the electronic part 1 is supported by a chip type part 3 when the electronic part 1 is to be soldered to the printed circuit board 2. Thereby, the solder bump 6 is formed in the shape of the column or drum like a connection bump 9 and size of gap between the electronic part 1 and printed circuit board 2 is determined by the height of the chip type part 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting technique for surface-mounting electronic parts, and more particularly to a BGA (Ball) which generates a large amount of heat.
The present invention relates to a technique effectively applied to a mounting method of an electronic component suitable for use in an electronic component such as a grid array type.

[0002]

2. Description of the Related Art For example, as a technique studied by the inventor, a technique as shown in FIG. 6 is conceivable as a method of mounting an electronic component such as a BGA type which generates a large amount of heat. As shown in the order of steps in FIGS. 6 (a) to 6 (d), this electronic component mounting method is applied to a substrate of an electronic component 1 formed of a ceramic or an organic material, such as copper or aluminum for heat diffusion. The structure is such that an electronic component 1 such as a BGA type having a structure in which a metal plate 4 having good thermal conductivity is attached and a solder bump 6 is provided is mounted on a printed board 2 via a connection bump 9a.

Regarding the technique relating to the mounting method of the electronic component such as the BGA type, for example, “Electronic Material 1994 Sep. 1994” published by Industrial Research Committee on Sep. 1, 1994.
Monthly issue "P44-P54 and the like.

[0004]

By the way, in the mounting technique of the electronic parts as described above, since the electronic parts, such as BGA type, which are laminated with the metal plates having good thermal conductivity, are mounted on the printed circuit board as they are, the connection is made. It is conceivable that the bumps support the weight of the electronic component by the surface tension of the bumps, and the connecting bumps have a barrel-shaped cross-sectional shape like a crushed ball.

That is, depending on the weight of the electronic component, when the solder bumps of BGA type or the like are melted and deformed during soldering, the wetting angle of the solder disappears and slippage occurs at the solder connection portion, and the electronic component is mounted at the mounting position. It is expected that the electronic components cannot be mounted on the board, and that the weight of the electronic component exceeds the surface tension of the solder bumps and crushes and short-circuits with the adjacent bumps.

Therefore, an object of the present invention is to prevent the solder bump from being excessively crushed and to control the bump height, thereby changing the shape of the bump from a barrel shape to a cylindrical shape or a drum shape, thereby improving the connection reliability of the connection portion. An object of the present invention is to provide a mounting method of an electronic component that can improve the property.

[0007]

The electronic component mounting method according to the present invention is applied to a case where an electronic component is mounted on a mounting substrate via solder bumps provided on the electronic component. The chip type component is provided on a part of the electronic component such as, or the chip type component is provided on a part of the substrate. As a result, the solder bumps are melted during soldering, and the height of the solder bumps can be controlled by supporting the solder bumps that are about to be crushed by the weight of the electronic component with the chip-type component.

Therefore, according to the above-described mounting method for electronic components, excessive bump crushing can be prevented, so that mounting position shift due to slippage of electronic components and short-circuiting between adjacent bumps can be eliminated, resulting in poor solder connection. Can be implemented.

Moreover, by supporting the chip type component, the shape of the solder bump can be changed from the barrel type to the columnar shape or the drum shape, and the mounting with high solder connection reliability can be realized. Furthermore, since the chip-type component is mounted under the electronic component, this chip-type component can be used as a bypass capacitor for suppressing power source noise.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic sectional view showing a method of mounting an electronic component according to a first embodiment of the present invention in the order of steps, and FIG. 2 is a rear view of the electronic component showing a mounted state of a chip type component. Is.

First, the structure of a mounting structure according to the mounting method for electronic components of the first embodiment will be described with reference to FIG.

The mounting structure of the electronic component mounting method according to the first embodiment is, for example, an electronic component mounting structure for mounting the electronic component on a mounting board via a solder bump provided on the electronic component. A mountable electronic component 1 and a printed board 2 (mounting board) on which the electronic component 1 is mounted,
The electronic component 1 is provided with a chip type component 3. The chip type component 3 controls the height of solder bumps when the electronic component 1 is soldered to the printed board 2.

The electronic component 1 is, for example, a surface mount type BGA type package which generates a large amount of heat, and is formed on the surface of the substrate of the electronic component 1 made of a ceramic or an organic material, such as copper or aluminum for heat diffusion. A metal plate 4 having good thermal conductivity is attached.

Further, a plurality of connection pads 5 are formed in an array at the center of the back surface of the electronic component 1, and solder bumps 6 are formed on these connection pads 5. Further, in the first embodiment, at least two portions are provided on the periphery of the back surface of the electronic component 1, and in the first embodiment, the chip-type component 3 is mounted on the connection pads 5 at the two corners in the diagonal direction as shown in FIG. There is.

A plurality of connection pads 7 are formed on the printed board 2 at positions corresponding to the solder bumps 6 of the electronic component 1, and a solder paste 8 is supplied to these connection pads 7 for soldering. The electronic component 1 is electrically connected to the printed board 2 via connection bumps 9.

The chip-type component 3 is, for example, a bypass capacitor for suppressing power source noise, and particularly, the chip-type component 3 has a predetermined height according to the gap dimension when the electronic component 1 is mounted on the printed board 2. The chip type component 3 is used. This chip-type component 3 includes an electronic component 1 and a printed board 2
When it is mounted on the electronic component 1, it is mounted on the connection pad 5 of the electronic component 1 by soldering in advance.

Next, regarding the operation of the first embodiment, a mounting method for mounting the electronic component 1 on the printed board 2 will be described in the order of steps based on FIG.

First, connection pads 7 are formed on the surface of the printed board 2 at positions corresponding to the solder bumps 6 of the electronic component 1 to be mounted (FIG. 1 (a)). The printed board 2 on which these connection pads 7 are formed is a generally known method,
For example, the subtractive method can be used. Then, the solder paste 8 is supplied to the connection pads 7 of the printed board 2 (FIG. 1 (b)).

Then, on the connection pad 5 of the electronic component 1,
The chip type component 3 is mounted by soldering, and then the solder bumps 6 are formed. Then, the solder bumps 6 of the electronic component 1 are positioned so as to correspond to the connection pads 7 formed on the printed circuit board 2, and the electronic components 1 are mounted on the printed circuit board 2 by overlapping (FIG. 1 (c)). ).

Further, the printed board 2 on which the electronic component 1 is mounted is placed in a heating furnace having a predetermined temperature according to the composition of the solder bumps 6 and the solder paste 8, for example. As a result, the electronic component 1 is soldered to the printed board 2 as illustrated in FIG. 1D by a reflow operation of heating and melting the solder bumps 6 and the solder paste 8.

At this time, in the case of the first embodiment, the solder bumps 6 that melt and tend to be crushed by the weight of the electronic component 1
With the chip type component 3 supporting the solder bumps 6, the solder bumps 6 can be formed into a columnar shape or a drum shape like the connection bumps 9.
Gap size between electronic component 1 and printed board 2 (standoff)
Can be determined by this chip type component 3.

For example, the solder paste 8 is formed to have the same shape, the same size, and a height of 200 μm as the connection pad 7. The chip-type component 3 mounted on the electronic component 1 is the 1608 type (1.6
mm × 0.8 mm) and the height is 0.5 mm, the solder bumps 6 are formed at the same height as the chip type component 3. When the electronic component 1 is mounted on the printed board 2, the solder bumps 6
Is in contact with the solder paste 8 and soldered by the reflow operation, the solder bumps 6 have a cylindrical shape at the height of the chip type component 3 such as the connection bumps 9 in FIG. It can be formed into a mold shape.

Therefore, according to the mounting method of the electronic component 1 of the first embodiment, the transient bumps are formed by forming the connection bumps 9 in the columnar shape or the drum shape by the chip type components 3 provided in the electronic component 1. Because it can prevent bump collapse,
It is possible to eliminate the mounting position shift of the electronic component 1 and the short-circuit between the adjacent bumps, and it is possible to realize the mounting of the BGA type electronic component 1 on the printed board 2 with few solder connection failures.

Further, the solder bumps 6 can be formed in a columnar shape or a drum shape like the connection bumps 9, and shear stress generated due to the difference in thermal contraction between the electronic component 1 and the printed board 2 like the barrel bumps. Connection bumps 9 and connection pads 5, 7
Since it does not concentrate on the interface of, the mounting with higher solder connection reliability can be performed.

Further, by mounting the chip type component 3 of the bypass capacitor on the electronic component 1, the electronic component 1 itself can be
Further, the power supply noise of the printed board 2 on which the electronic component 1 is mounted can be suppressed and the characteristics can be improved.

(Embodiment 2) FIG. 3 is a schematic sectional view showing a method of mounting an electronic component according to Embodiment 2 of the present invention in the order of steps.

The mounting structure of the electronic component mounting method according to the second embodiment is similar to that of the first embodiment, in that the electronic component is mounted on the mounting board via the solder bumps provided on the electronic component. The electronic component 1 has a component mounting structure, and includes a surface mount type electronic component 1, a printed board 2 (mounting substrate) on which the electronic component 1 is mounted, and a chip type component 3 of a bypass capacitor. The difference is that the chip type component 3 is provided on the printed board 2 instead of the electronic component 1.

That is, in the method of mounting the electronic component 1 according to the second embodiment, the electronic component 1 is mounted on the printed board 2 based on the order of steps shown in FIG. Solder bumps 6 of the electronic component 1 to be mounted and connection pads 7 are formed on the surface at positions corresponding to the chip type component 3 (FIG. 3A). Then, the chip type component 3 is mounted on the printed board 2 and soldered (FIG. 3 (b)).

Subsequently, the solder paste 8 is supplied to the connection pads 5 of the printed board 2 corresponding to the solder bumps 6 of the electronic component 1 (FIG. 3 (c)). Then, the solder bumps 6 of the electronic component 1 are attached to the connection pads 7 formed on the printed board 2.
The electronic components 1 are mounted on the printed board 2 by positioning so as to correspond to each other and superposing them (FIG. 3 (d)).

After that, the solder bumps 6 and the solder paste 8 are subjected to the reflow operation as in the first embodiment.
Is melted by heating the solder bumps 6 and the chip type parts 3
Supported by the solder bumps 6, the solder bumps 6 can be formed into a columnar shape or a drum shape like the connection bumps 9 (FIG. 3).
(e)).

Therefore, according to the mounting method of the electronic component 1 of the second embodiment, the connection bump 9 is formed in the columnar shape or the drum shape by the chip type component 3 provided on the printed board 2. As in the first embodiment, by mounting position deviation of the electronic component 1, prevention of short circuit between adjacent bumps, and relaxation of shear stress, the electronic component 1 having high solder connection reliability can be mounted on the printed board 2, and the electronic component can be realized. It is possible to suppress the power supply noise of the printed board 2 on which 1 is mounted and improve the characteristics.

In particular, when the chip type component 3 of the bypass capacitor is provided on the printed board 2 as in the second embodiment, the characteristics can be improved by suppressing the power source noise, and the chip type component 3 is connected to the circuit. Since the mounting area of the printed board 2 can be made large in common with the constituent parts, the mounting efficiency of the chip type part 3 and further the electronic part 1 can be improved.

Needless to say, the present invention is not limited to the first and second embodiments described above, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, the case where the chip-type component 3 is provided at two places with respect to the electronic component 1 has been described, but the present invention is not limited to the above-described embodiment, and the number required in terms of characteristics 4, the chip-type component 3 may be provided at three or four locations as shown in FIG. 4, or more locations may be provided, or the chip-type components 3 may be modified depending on the arrangement of the bumps 6. The present invention is also widely applicable to the case where the chip type component 3 is provided in the central portion as shown in FIG.

Further, the chip type component 3 is not limited to a bypass capacitor, but can be applied to other chip type components 3 such as diodes and resistors. In this case, the chip type component 3 is a circuit component. Since it can be shared as a part, the mounting efficiency can be improved.

Further, the height of the chip type component 3 is not only 0.5 mm, but also the gap between the electronic component 1 and the printed board 2 due to the size of the electronic component 1, the pitch size of the connection pads 5, etc. It is needless to say that it is possible to control to various heights by using an existing chip-type component or a newly-produced chip-type component according to the size.

[0037]

According to the electronic component mounting method of the present invention,
When soldering an electronic component to a mounting board, the height of the solder bump can be controlled by a chip-type component provided on the electronic component or a part of the mounting board to prevent excessive bump crushing. It is possible to reduce the mounting position shift due to component slippage and the like, and a short circuit between adjacent bumps.

As a result, the connection failure of the solder bumps can be reduced, so that the connection reliability when mounting the electronic component on the mounting board via the solder bumps can be improved.

Further, according to the present invention, by mounting the chip type component on the electronic component or the printed circuit board, the chip type component can be shared with the circuit component and the mounting area of the printed board can be increased. It is possible to improve the mounting efficiency of chip type components and electronic components.

In particular, when the chip type component is used as a bypass capacitor, the chip type component can be used for suppressing power source noise. Therefore, the electronic component itself and the power source of the printed board on which the electronic component is mounted are used. It is possible to suppress noise and improve the characteristics.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a method of mounting an electronic component according to a first embodiment of the present invention in the order of steps.

FIG. 2 is a rear view of the electronic component showing the mounting state of the chip-type component in the first embodiment.

FIG. 3 is a schematic cross-sectional view showing a method of mounting an electronic component according to the second embodiment of the present invention in the order of steps.

FIG. 4 is a back view of the electronic component showing a mounting state of another chip-type component in the embodiment.

FIG. 5 is a back view of the electronic component showing a mounting state of still another chip-type component in the embodiment.

FIG. 6 is a schematic cross-sectional view showing a method of mounting an electronic component, which is a comparative example corresponding to the embodiment of the present invention, in the order of steps.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electronic component, 2 ... Printed board (mounting board), 3 ... Chip type component, 4 ... Metal plate, 5 ... Connection pad, 6 ... Solder bump, 7 ... Connection pad, 8 ... Solder paste, 9 ... Connection bump.

Front Page Continuation (72) Inventor Yasuhiro Uemura 1 Horiyamashita, Hinoyama, Hadano, Kanagawa Pref., Inside Hitsuyama Computer Electronics Co., Ltd. (72) Inventor, Masakazu Sakagami 810 Shimoimaizumi, Ebina, Kanagawa Hitachi Systems Office Systems Business Department

Claims (1)

[Claims] 1. A method of mounting an electronic component on a mounting board through a solder bump provided on the electronic component, the method comprising: mounting the electronic component on a place other than the solder bump. Alternatively, at least two chip-type components having a predetermined height are provided at one of the places where the electronic component is mounted on the mounting board, and the solder is used when soldering the electronic component to the mounting substrate. A method of mounting an electronic component, comprising: controlling the height of the solder bump by supporting the solder bump that melts and is crushed by the weight of the electronic component with the chip-type component.