JPH06112624A - Surface mounting method - Google Patents

Abstract

PURPOSE:To improve reliability and to realize compactness and a low cost by overlapping and fixing a plurality of packages to have their front and rear faced with each other and by connecting a terminal row exposed in the same direction through one or more printed boards. CONSTITUTION:A module printed board 104 whereto cream solder is applied is prepared for a PAD 103 corresponding to a terminal row 102 on one side of an SOJ (Small Outline J-Lead) package (IC) 101. A Y-axis of the SOJ package (IC) 101 is arranged in a position corresponding to the PAD 103 fitting to a vertical direction of a surface of the module printed board 104. Similarly, a plurality of SOJ packages (IC) 105 to 111 are fixed with the front and the rear thereof overlapping each other in a Z-axis direction. A printed board 113 whereto cream solder is similarly applied is arranged also in another terminal row 112 which is opposite to the terminal row 102 on the one side of the SOJ package. Soldering is carried out by making it pass through a furnace and a module is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting an IC for surface mounting, particularly Small Outline J-Lead (hereinafter referred to as SOJ) and Plastic Lead Chip Carrier (hereinafter referred to as PL).
The present invention relates to a surface mounting method of a package called CC).

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional surface mounting IC mounting method. Surface mounting is generally implemented as shown in FIG. That is, the IC packages 302 to 309 are mounted with the surface (the surface on which the manufacturer's marking is applied) facing upward with respect to the surface of the substrate 301. Here, an example of the SOJ package is shown. A similar mounting method is performed by a so-called surface mount IC such as PLCC. This I
The C packages 302 to 309 and this mounting method are
This is a very important and useful way to miniaturize electronic devices using the C packages 302 to 309. In other words, the package itself has become smaller, and the DI
ICs on both sides of the board compared to P (Dual Inline Package) ICs
Can be mounted, which can further contribute to downsizing of the board.

As a typical example of using this method, a DRAM (Dynamic RAM) module used in a personal computer, a workstation, etc. has been proposed. By using this method, both sides of the substrate can be used as compared with the case where a conventional DIPIC (Dual Inline Package IC) is used for mounting the IC, and the substrate can be formed with about half the substrate area.

However, in the past, this is the limit, and it is not possible to expect a reduction in the substrate area more than half that of the DIPIC. Therefore, the MCM (Multi Chip Module) method is proposed. MC
The M has a shape as shown in FIG. 6, in which a plurality of so-called IC chips called bare chips 402 to 405 are mounted in one package 401, and a micron-order pattern 406 is formed on a ceramic substrate 407 in the package. By pulling up, I have implemented multiple packages until now. I
This is a technique for reducing the substrate area by combining C chips into one package. However, this method is still in the research stage, and in practical use, there are still many problems to be solved such as package reliability and cost.

[0005]

However, as described above, in the present technology, the size of the substrate can be reduced to about half of the area of the substrate formed by the conventional DIPIC, and further miniaturization is desired. However, there is still no effective and easy way to achieve it. The present invention solves the above conventional problems, and an object of the present invention is to provide a highly reliable, compact, and low-cost surface mounting method.

[0006]

In order to achieve the above-mentioned object, the present invention is only for PLCC and SOJ packages, but a plurality of packages are superposed on the surface (the side having the marking of the manufacturer) and the back side thereof. A mounting method is used in which terminal rows (two sides in the case of SOJ, four sides in the case of PLCC) that are exposed in the same direction are connected by one or more printed circuit boards (hereinafter, the connected state is called a module). Each printed circuit board of the module (2 sheets for SOJ, PLC
There are card-edge-shaped or pin-shaped terminals for connecting to another board from 4) in the case of C), and these terminals are used to mount on another board.

[0007]

EXAMPLE An SOJ mounting method according to an example of the present invention will be described with reference to FIGS. First, in order to clarify the coordinate axes, the direction is determined in the form as shown in FIG. That is, the terminal row direction of one side is the X axis, the normal direction to the opposing terminal row is the Y axis, and the direction perpendicular to the X axis and the Y axis is the Z axis.

FIG. 1 shows the content of the present invention in more detail.
Here, 101, 105 to 111 are IC SOJ packages, and 102 and 112 are terminal arrays (S) of the SOJ package (IC) 101.
OJ package one side terminal row), 103 is a wiring pattern (usually referred to as PAD, hereinafter referred to as PAD) on the printed circuit board corresponding to the terminal row 102, 104 and 113 are the PAD 103 and the board wiring patterns 117 and 118. It is a printed circuit board for modules including. 119 and 120 are holes corresponding to pin type terminal groups 114 and 115 arranged to connect the module printed circuit boards 104 and 113 to another board 116 (usually called lands, hereinafter referred to as lands). ). The pin-type terminal groups 114 and 115 and the PAD 103 and the like have wiring patterns 117 and 118.
It is electrically connected with.

First, a module printed circuit board 104 is prepared by applying cream solder to a PAD 103 corresponding to a terminal row 102 (on the side opposite to the SOJ package 101 in FIG. 1) on one side of the SOJ package (IC) 101, and a position corresponding to the PAD 103 is prepared. Then, the Y axis of the SOJ package (IC) 101 is aligned with the surface of the module printed board 104 in the vertical direction. Similarly, a plurality of SOJ packages (IC) 105 to 111 are superposed on the surface of each SOJ package (IC) 101, 105 to 111 (the side on which the manufacturer's marking is provided) and the back side thereof, that is, in the Z-axis direction. Fix it. Further, a printed circuit board 113 to which cream solder is similarly applied is arranged also on the other terminal row 112 (terminal row on one side of the SOJ package) facing the terminal row 102 on one side of the SOJ package, and this is passed through a furnace. Solder to complete the module. Pattern edge type terminal groups or pin type terminal groups 114, 115 are provided at the ends of the module printed circuit boards 104, 113.
Are prepared and can be easily connected to each other by using another board 116 and lands 119 and 120.

Further, it is apparent that the cooling effect is enhanced by ventilation by opening the spaces between the SOJ package ICs. Although the SOJ package IC has been described in the embodiment, it is obvious that the present invention has the same effect also in the PLCC package IC as shown in FIG. If you use a module with such a configuration,
The area of 116 can be reduced significantly. In this embodiment, about 1 in the SOJ package (IC) 101 portion of the other substrate 116.
The substrate area was reduced by / 7 (illustrated in FIG. 4).

[0011]

In the embodiment of the present invention, the PL
As for the CC and SOJ packages only, by stacking and fixing the chips, connecting the terminal portions with the substrate, using terminals for connecting the substrate to the main substrate, and using a means for three-dimensionally mounting, The effect is that the substrate area of only the SOJ portion can be reduced by about 1/7.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a substrate using a surface mounting method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a direction of an SOJ package.

FIG. 3 is a diagram showing an embodiment in which the present invention is applied to a PLCC package.

FIG. 4 is a diagram showing a difference in board occupying area between a mounting method according to an embodiment of the present invention, a conventional mounting method, and a conventional module-type mounting method.

FIG. 5 is a diagram showing a conventional DRAM module.

FIG. 6 is a diagram showing a conventional multi-chip module (MCM).

[Explanation of symbols]

101,105-111 ... SOJ package, 102,112 ... SO
Terminal line on one side of J package, 103 ... Wiring pattern (PAD) on printed circuit board, 104, 113 ... Module printed circuit board, 114, 115 ... Pin type terminal group, 116 ...
Other boards, 117, 118 ... Board wiring patterns, 119, 120
… Hole (land), 301… Substrate, 302-309… IC package, 401… Package, 402–405… Bare chip,
406 ... Pattern, 407 ... Ceramic substrate.

Claims (3)

[Claims] 1. A surface mounting method for a surface mounting integrated circuit (IC for surface mounting), wherein a surface in contact with all terminals on both side surfaces of the IC is an XY plane, and a direction perpendicular to the XY plane is Z axis.
At least one or more printed circuit boards on which the ICs are mounted are all in contact with the terminal row on one side and arranged parallel to the Z-axis, and at least one or more printed circuit boards are provided for the remaining one or three terminal rows. Is arranged parallel to the Z-axis, and the front side of the IC (the XY plane and the surface with the marking of the manufacturer)
A surface mounting method, wherein the IC group is mounted in a shape in which the back and the back are overlapped. 2. The surface mounting method according to claim 1, wherein the printed circuit board has terminals arranged in a card edge shape or a pin shape so as to be mounted on another board. 3. The surface mounting method according to claim 1, wherein an interval between the IC groups is opened for ventilation.