JPH08340164A - Surface mounting structure of bga type package - Google Patents

Abstract

PURPOSE: To obtain a highly reliable mounting circuit device formed into a structure, wherein when solder balls are made to reflow, the solder balls are over-crushed and a BGA type package and a surface mounting circuit board are never short-circuited with each other, by a method wherein interval holding means for holding the interval between the BGA type package and the surface mounting circuit board are previously annexed on the four corners of the BGA type package. CONSTITUTION: A component 3 is mounted on the surface of a double-side printed board 2, the upper surface of the component 3 is resin-molded 5, a multitude of first soldered lands 2a are formed on the back of the board 2 and solder balls 6 are connected with the lands 2a. Such a BGA type package 1 is mounted on a surface mounting circuit board 8 provided with second soldered lands 9 to correspond to the balls 6. In such a mounting structure, interval holding means 7 for holding the interval between the package 1 and the board 8 are previously annexed on the four corners of the board 2. For example, positioning pins 7 are dropped almost vertically to mounting holes 2b provided in the four corners of the board 2 and are mounted to the holes 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mounting structure of a BGA type package, and more particularly to a surface mounting structure capable of mounting a BGA type package having a large number of solder balls with high accuracy and easily. .

[0002]

2. Description of the Related Art For example, a high-density packaging circuit device (hybrid module) has been developed for the purpose of downsizing electronic devices or electronic circuits or improving their functions. In a BGA (Ball Grid Array) type package as a package mounting format in this high-density mounting circuit device, for example, a large number of solder balls derived from a double-sided printed circuit board are positioned on corresponding connection lands of a surface mounting circuit board. However, electrical connection (mounting) is performed by soldering or the like. FIG. 9 schematically shows the mounting state of the mounting type, in which parts such as the semiconductor chip 3 are mounted on the upper surface of the double-sided printed board 2, and the parts and the circuit on the double-sided printed board 2 are electrically connected by wires 4. Are electrically connected to each other, the upper surfaces thereof are molded with resin 5, the first soldering lands 2a are formed on the lower surface, and the solder balls 6 are bonded to the first soldering lands 2a. The second soldering land 9 formed on the surface of the surface mounting circuit board 8 on the solder ball 6 of the BGA type package 1 thus formed.
So that they correspond, for example, by visually locating,
The solder balls 6 and the second soldering lands 9 are joined (mounted) by reflowing.

However, the BGA type package 1
In the structure of the surface mounting structure, there are the following problems, which pose problems for practical use. That is, in the case of the BGA type package 1, since a large number of solder balls 6 hang down from the lower surface, when positioning is performed in correspondence with the second solder land 9 provided on the surface mounting circuit board 8. , The connection portion of the solder ball 6 with the second solder land 9 is located on the back surface of the BGA type package 1 (a position that is difficult to visually recognize). In other words, the positioning is performed in a relatively difficult state, and the required mounting is completed while it is difficult to check after mounting and mounting, and there is a problem in connection reliability. In particular, since the solder ball 6 has a diameter of, for example, 0.76 ± 0.1 mm and is close to a true sphere, the accuracy of positioning the solder ball 6 and the soldering land 8 is high in order to achieve reliable electrical connection. Be valued.

If the distance between the BGA type package 1 and the surface mounting circuit board 8 is not properly maintained, the solder balls 6 are crushed too much as shown in FIG. 10 when the solder balls 6 are reflowed. There is a problem that the solder balls 6 are short-circuited with each other.

[0005]

The present technology has been made in view of the above problems. When the BGA type package 2 is positioned with high accuracy and reflowed, the solder balls 6 are excessively crushed and short-circuited to each other. An object of the present invention is to provide a surface mounting structure of a BGA type package capable of forming a highly reliable mounting circuit device.

[0006]

In order to solve the above-mentioned problems, the present invention mounts parts on the surface of a double-sided printed circuit board,
A BGA (Ball Grid Arra) in which the upper surface of the same component is resin-molded, a large number of first soldering lands are formed on the back surface, and solder balls are connected to the first soldering lands.
y) The type package is mounted on a surface mounting circuit board having second soldering lands corresponding to the solder balls, and the BGA type package is mounted at four corners of the BGA type package.
A space holding means for holding a space between the die package and the surface mounting circuit board is provided in advance. Also,
The space holding means is a pin. Further, a BGA in which a component is mounted on the front surface of a double-sided printed circuit board, the upper surface of the component is resin-molded, a large number of first soldering lands are formed on the rear surface, and solder balls are connected to the first soldering land. In a package for mounting a (Ball Grid Array) type package on a surface mounting circuit board provided with a second soldering land corresponding to the solder ball,
Space holding means for holding the space between the BGA type package and the surface mounting circuit board is attached in advance at four corners of the BGA type package, while positioning means corresponding to the space holding means is attached in advance on the surface mounting circuit board. It is characterized by having done. Furthermore, the positioning means is a hole. Further, the positioning means is a hole, and further, a step portion facing inward is provided at a lower end of the pin.

[0007]

With the above construction, the BG according to the present invention
In the surface-mounting structure of the A-type package, the pins as the space holding means prevent the solder balls from being excessively crushed in the BGA-type package, and the holes as the positioning means are provided in the surface-mounting circuit board as the solder balls of the BGA type package. Can be easily and accurately positioned on the corresponding solder land on the surface of the surface mounting circuit board.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The reference numerals in the figure are the same as those in the conventional example.

In FIG. 1, reference numeral 1 denotes a BGA type package, in which a component 3 such as a semiconductor chip is mounted on a double-sided printed board 2 and the semiconductor chip 3 and the double-sided printed board 2 are connected by a wire 4. It is joined. Further, the double-sided printed circuit board 2, the component 3 and the wire 4 are molded with a resin 5 such as silicon rubber. Further, a first soldering land 2a is formed on the lower surface of the double-sided printed circuit board 2, a solder ball 6 is attached to the land 2a, and the land is passed through an electric furnace or is heated and melted by a hot pot. Is bonded to the first soldering land 2a. Further, mounting holes 2b are provided at four corners, and the mounting holes 2b each have a positioning pin 7 having a diameter slightly smaller than the diameter of the solder ball 6.
Is installed almost vertically. On the other hand, 8 is a surface-mounting circuit board made of a printed substrate, and a second soldering land 9 corresponding to the first soldering land 2a of the BGA type package 1 is provided on the upper surface of the same surface-mounting circuit board 1. Are formed.

The mounting affirmation of the BGA type package 1 having the above structure will be described below. After the solder paste is selectively applied to the second soldering lands 9 of the surface-mounting circuit board 8 by, for example, a screen printing method, the solder balls 6 of the BGA type package 1 are respectively applied as shown in FIG. The BGA type package 1 and the surface-mounting circuit board 8 are brought into contact with the pins 7 as the space holding means of the BGA type package 1 while being positioned corresponding to the second soldering lands 9. , For example, by reflowing, they are easily and reliably connected to each other to complete the required mounting while forming a reliable electrical connection. As described above, the solder balls 6 are formed by the reflow.
Even if the pin is crushed, the pin is not crushed to have a diameter shorter than the length of the pin 7.

FIG. 3 is a view for explaining the positioning means of the surface mount component according to the present invention. In this embodiment, 1 is BG.
In the A type package, a component 3 such as a semiconductor chip is attached to the upper surface of the double-sided printed board 2 of the BGA type package 1, and the semiconductor chip 3 and the double-sided printed board 2 are joined by a wire 4. Further, the double-sided printed board 2, the component 3 and the wire 4 are made of resin 5 such as silicon rubber.
Is molded by. Further, a first soldering land 2a for joining a solder ball 6 described later is formed on the lower surface of the double-sided printed board 2. Further, mounting holes 2b are provided on both sides, and pins 7 longer than the diameter of the solder balls 6 are mounted in the mounting holes 2b so as to hang down substantially vertically. 6 is a solder ball, which is attached so as to abut the first soldering land 2a and is passed through an electric furnace, or is joined to the BGA type package 1 by being heated and melted by a hot put. To be done. On the other hand, 8 is a surface-mounting circuit board made of a printed substrate, and a second soldering land 9 corresponding to the first soldering land 2a of the BGA type package 1 is provided on the upper surface of the same surface-mounting circuit board 1. And a concave portion 8b as a positioning means with which the pin 7 of the BGA type package 1 is fitted.
Are formed.

After the solder paste is selectively applied to the second soldering lands 9 of the surface-mounting circuit board 8 by, for example, a screen printing method, the pins 7 are formed in the corresponding recesses 8b as shown by an arrow A. Position and fit to solder ball 6
By making each of them correspond to the corresponding second soldering land 9 and reflowing the BGA type package 1 and the surface mounting circuit board 8 in this state, as shown in FIG. Connect to form a reliable electrical connection, completing the required mounting.

In the above description, the surface mounting circuit board 8 having the recess 8b into which the pin 7 of the BGA type package 1 is fitted is used. However, as shown in FIG. It may be performed by fitting into the hole 8c provided in the mounting circuit board 1.

FIGS. 6 and 7 show another embodiment for maintaining the substrate spacing of the surface mounting structure of the BGA type package according to the present invention. As shown in FIG. 7b, and the thickness of the stepped portion 7b is set to the mounting hole 8
The diameter of the upper portion 7a of the step portion 7b is made slightly thinner than that of the mounting hole 8d, and the step portion 7b of the pin 7 is fitted into the hole 8d as shown in FIG. Thus, the required substrate spacing is maintained as in the above.

In the above description, the surface mounting circuit board 8 having the recessed portion 8d into which the step portion 7b of the pin 7 of the BGA type package 1 is fitted is used, but as shown in FIG. The positioning of the step 7 by the step portion 7b may be performed by fitting into the hole 8e provided in the surface mounting circuit board 1.

[0016]

As described above, B according to the present invention
According to the surface mounting structure of the GA type package, the solder balls of the BGA type package are easily and accurately positioned on the corresponding soldering lands of the surface mounting circuit board for electrical connection or mounting. That is, the solder balls of the BGA type package are soldered in a state where they are accurately positioned and securely contacted with the corresponding connection land surface of the surface mounting circuit board, even though the connection surface is minute. Since the solder balls are connected and excessive crushing of the solder balls is prevented, a short circuit between the solder balls does not occur,
Sufficient bonding accuracy and reliable electrical connection are easily achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part of a substrate spacing holding means of a surface mounting structure of a BGA type package according to the present invention.

FIG. 2 is a cross-sectional view of an essential part of a substrate spacing holding means of a surface mounting structure of a BGA type package according to the present invention.

FIG. 3 is a cross-sectional view of essential parts of a second embodiment of the surface mounting structure of the BGA type package according to the present invention.

FIG. 4 is a cross-sectional view of essential parts of a second embodiment of the surface mounting structure of the BGA type package according to the present invention.

FIG. 5 is a cross-sectional view of an essential part of a third embodiment of the surface mounting structure of the BGA type package according to the present invention.

FIG. 6 is a cross-sectional view of an essential part of a fourth embodiment of the surface mounting structure of the BGA type package according to the present invention.

FIG. 7 is a cross-sectional view of a main part of a fourth embodiment of the surface mounting structure of the BGA type package according to the present invention.

FIG. 8 is a cross-sectional view of essential parts of a fifth embodiment of the surface mounting structure of the BGA type package according to the present invention.

FIG. 9 is a cross-sectional view of an essential part showing a conventional surface mounting structure of a BGA type package.

FIG. 10 is a cross-sectional view of an essential part for explaining a solder ball of a surface mounting structure of a conventional BGA type package.

[Explanation of symbols]

 1 BGA type package 2 Double-sided printed circuit board 2a First soldering land 2b Mounting hole 3 Semiconductor chip 4 Wire 5 Resin mold 6 Solder ball 7 Pin 8 Surface mounting circuit board 8b Hole 9 Second soldering land

Claims (6)

[Claims] 1. A component is mounted on the front surface of a double-sided printed circuit board, the upper surface of the component is resin-molded, and a large number of first components are formed on the rear surface.
BGA (Ball Grid Arr) in which a soldering land is formed and a solder ball is connected to the first soldering land.
ay) type package with a second package corresponding to the solder balls
In the case of mounting on a surface mounting circuit board having soldering lands, the BGA is provided at four corners of the double-sided printed board.
A surface mounting structure of a BGA type package, characterized in that space holding means for holding a space between the die package and the surface mounting circuit board is provided in advance. 2. The surface mounting structure for a BGA type package according to claim 1, wherein the spacing holding means is a pin. 3. A component is mounted on the front surface of a double-sided printed circuit board, the upper surface of the component is resin-molded, and a large number of first parts are formed on the rear surface.
BGA (Ball Grid Arr) in which a soldering land is formed and a solder ball is connected to the first soldering land.
ay) type package with a second package corresponding to the solder balls
Which is mounted on a surface mounting circuit board having soldering lands, the same BGA is provided at four corners of the BGA type package.
A BGA type characterized in that a space holding means for holding a space between the die package and the surface mounting circuit board is preliminarily provided, while a positioning means corresponding to the space holding means is preliminarily provided on the surface mounting circuit board. Surface mounting structure of the package. 4. The surface mounting structure for a BGA type package according to claim 3, wherein the positioning means is a hole. 5. The surface mounting structure for a BGA type package according to claim 3, wherein the positioning means is a hole. 6. The surface mounting structure for a BGA type package according to claim 1, wherein a step portion facing inward is provided at a lower end of the pin.