JP2001053213A - Surface mount electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a multiple pin package by leading out a large number of surface connecting pins from a package while preventing generation of a solder bridge by directing all of a plurality of the surface connecting pins led out from a package body in the same direction in mutually parallel for a surface mount electronic part. SOLUTION: A package body 1 for the QFP semiconductor integrated circuit electronic part is formed in a square, and surface connecting pins 2 for inputs and outputs as a plurality of leads are led out from the four side of the package body 1. These all surface connecting pins 2 are arrange directed in the same direction in mutually parallel. The surface connecting pins 2 are inclined at an angle less than 90 deg. such as 45 deg. to an edge side 1a, from which the surface connecting pins 2 are led out. The inclination to the edge side 1a of the package body 1 of the surface connecting pins 2 can be changed by the shape of the package body 1, application of the surface mount electronic part or the like. Thus, a solder bridge between the adjacent surface connecting pins is hardly made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount electronic component such as a QFP and, more particularly, to a surface mount electronic component for preventing a solder bridge generated between fine pitched surface connection pins.

[0002]

2. Description of the Related Art In general, a surface mount type electronic component having a package structure is mounted on a lead frame by an integrated circuit (IC
(Integrate Circuit)) A bare chip is mounted, wired using wire bonding, the IC bare chip is integrated with a part of the lead frame by molding resin to form a main body, and then the lead frame is processed into a desired shape. Are used as surface connection pins.

When the number of output pins of an IC bare chip is small, the SOP (Small Outl) in which the surface connection pins are led out in two directions.
ine Package). FIG. 5 is a plan view showing the SOP. As shown in FIG. 5, the surface connection pins 2 for surface mounting are mounted on the rectangular package body 1 in a direction perpendicular to the edge.
In addition, it is derived into a gull wing shape (a shape with seagulls spreading their wings) in a side view. Such an SOP has the advantage that the appearance inspection after mounting is easy and the contact can be easily made with the inspection socket.

An SOP in which the surface connection pins 2 are derived from only two opposing sides of the four sides of the package body 1
In the batch flow soldering using the automatic soldering device, the direction A shown in FIG.
When soldering is performed from a direction perpendicular to the longitudinal direction of the solder, peelback is likely to occur because the longitudinal direction of the surface connection pins 2 is perpendicular to the supply direction of the solder, and no solder bridge occurs. However, in the B direction, that is, the surface connection pin 2
When the solder is supplied in a direction along the longitudinal direction of the solder, since there is no place for the excess solder in the supplied solder to escape, solder bridges frequently occur. Therefore, when an SOP is mounted on a printed circuit board using a batch flow soldering apparatus, solder bridges are prevented by taking into account the mounting direction of the SOP when designing the printed circuit board.

In recent years, the demand for further miniaturization of semiconductor devices has further increased the density of semiconductor devices, and as a result, the number of input / output pins has increased. QFPs derived from edges have been developed and used extensively. FIG. 6 is a plan view showing a conventional QFP. As shown in FIG. 6, in the QFP, the surface connection pins 2 are led out from four sides of the square package body 1 vertically to each side. In such a QFP, when the package dimensions are the same, the surface connection pins can be derived from four sides as compared with the SOP, so that the number of pins can be increased.

[0006]

However, the conventional QFP has a surface connection pin of a rectangular package body.
Since soldering is performed using a batch flow soldering device, the soldering in the direction A and the soldering in the direction B shown in FIG. It happens at the same time. That is, in FIG. 6, when soldering is performed in the direction A perpendicular to the surface connection pins derived from one side of the package body, the surface connection pins derived from both sides thereof are pinned. Therefore, there is a problem that a solder bridge is easily generated in the surface connection pins.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and is a multi-pin type surface mount electronic component in which a large number of surface connection pins are derived from a package and in which the occurrence of solder bridges can be prevented. The purpose is to provide.

[0008]

A surface-mount electronic component according to the present invention has a polygonal package body and surface connection pins derived from the package body, and all the surface connection pins are parallel to each other. , And at least a part of the surface connection pins is 90 ° with respect to the edge of the package body from which the surface connection pins are led out.
It is characterized by being inclined at an angle θ less than ゜.

Further, the package body has a rectangular shape, for example, and the surface connection pins are led out from all four sides and face in the same direction.

Further, the package body has a rectangular shape, for example, and the surface connection pins are led out from only three sides and face the same direction.

Further, the package main body has, for example, a square shape, and an angle θ formed between the edge of the package main body from which the surface connection pins are led out and the surface connection pins.
Is 45 °.

Another surface-mounted electronic component according to the present invention has a package body whose edge is formed by a curved line, and surface connection pins derived from the package body, and all the surface connection pins are parallel to each other. Characterized in that it faces in one direction.

The surface mount electronic component according to the present invention can be subjected to a batch solder flow process by passing the surface mount pin in a direction perpendicular to the longitudinal direction of the surface connection pin.

In the present invention, when performing the batch flow soldering to connect the surface mount electronic components on the printed circuit board, all the surface connection pins derived from the package body are parallel to each other and face in the same direction. Since they are arranged, all the surface connection pins can be soldered in a direction orthogonal to the longitudinal direction. Therefore, since the longitudinal direction of the surface connection pins is orthogonal to the supply direction of the solder, peelback is likely to occur, and a solder bridge is unlikely to occur between the surface connection pins.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A surface mount electronic component according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a plan view showing a surface-mounted electronic component according to the present embodiment. As shown in FIG. 1, the package body 1 of the QFP type semiconductor integrated circuit electronic component has a square shape, and input / output surface connection pins 2 as a plurality of leads are respectively led out from four sides of the package body 1. All these surface connection pins 2 are arranged so as to be parallel to each other and to face in the same direction.

FIGS. 2A and 2B are diagrams showing the structure of the surface connection pins of the surface-mounted electronic component according to the present embodiment, wherein FIG. (b) is a side view of (a). As shown in FIG. 2A, the surface connection pins 2 are inclined at 45 ° with respect to the edge 1a from which the surface connection pins 2 are led out.

As shown in FIG. 2B, the surface connection pin 2 is a gull-wing-shaped lead in side view.
This is a general QFP type semiconductor integrated circuit component derived from the edge 1a of the package body 1 as a plurality of input / output terminals.

The package body 1 of the surface connection pins 2
Can be appropriately changed according to the shape of the package body 1 or the use of the surface mount electronic component.
Further, all the surface connection pins 2 need only be parallel to each other and face in the same direction. As shown in FIG.
The positions where the surface connection pins 2 are formed may not be the same on adjacent sides.

Next, the operation of the surface-mounted electronic component configured as described above will be described. To connect the surface-mounted electronic components to the printed circuit board, the surface mounting pins of the surface-mounted electronic components are positioned and mounted on each pad on the printed circuit board. Then, the surface mount electronic components are connected to the printed circuit board by flow soldering. FIG. 3 is a sectional view showing an automatic batch soldering apparatus.

As shown in FIG. 3, an automatic batch soldering apparatus 1
0, the molten solder 13 is stored in a solder bath 11 made of a heat insulating material, and the molten solder 13 is heated by a heater 12 mounted inside the solder bath 11, thereby keeping the temperature of the molten solder 13 constant. I'm dripping. The solder bath 11 is partitioned by a partition 23 provided horizontally inside. The partition 23 has a cylindrical nozzle 18 perpendicular to the partition surface and projecting upward from the upper end of the solder bath 11 and a lower portion. Cylindrical pump support 22 protruding into
Are formed. The pump 1 has a pump 1
7 is supported, and the molten solder 13 in the solder bath 11 is fed into the nozzle 18 by the pump 17,
The molten solder 13 overflowing from the upper end of the nozzle 18 is returned to the partition 23. A motor 15 and a transmission 16 are provided outside the solder bath 11, and the transmission 16
It is connected to the motor 15 and adjusts the rotation speed of the motor 15. A drive shaft extends downward from the transmission 16 and is connected to the pump 17 in the solder bath 11. This allows
After the rotation of the motor 15 is shifted, it is transmitted to the pump 17. A thermocouple 21 is provided near the pump 17 and the heater 12, detects the temperature of the molten solder 13, and controls the heater 12 so that the temperature becomes constant.

The operation of the thus configured batch flow soldering apparatus will be described. First, when the motor 15 is driven, the pump 17 is driven via the transmission 16,
As a result, the molten solder 13 in the solder bath 11
8 is sent. Then, the molten solder 13 jets upward from a nozzle 18 projecting above the upper end of the solder bath 11. A printed circuit board is disposed above the nozzle 18, and the jet wave front 19 of the molten solder 13 contacts the surface connection pins of the surface-mounted electronic component temporarily fixed to the printed circuit board by the supply amount of the molten solder 13 by the pump 17. The height (wave height) 20 of the jet is adjusted so that the molten solder 13 is supplied to the surface connection pins. At this time, the batch flow soldering can be performed by moving the printed board above the nozzle 18. Then, the excess molten solder 13 is removed from the solder bath 1 again.
1, the molten solder 13 circulates in the solder bath 11 by being jetted again from the nozzle 18 by the pump 17.

FIGS. 4A to 4D are schematic diagrams for explaining the relationship between the direction of the collective flow soldering and the surface connection pins. The surface mount electronic component shown in FIG. 4 shows the SOP shown in the conventional example. In the SOP, surface connection pins 2 are derived only from the long sides of the four sides of the rectangular package body 1. When the SOP having such a configuration is joined to a printed board, the printed board is moved in a direction along the side of the package body 1 of the SOP by using an automatic batch soldering apparatus as shown in FIG. Is performed, there are two directions of soldering: a direction along the longitudinal direction of the surface connection pins 2 derived from the package body 1 and a direction orthogonal to the longitudinal direction of the surface connection pins 2. FIGS. 4A and 4B are schematic diagrams showing a case where soldering is performed in a direction (A direction) orthogonal to the longitudinal direction of the surface connection pins 2. As shown in FIG. 4B, a molten solder 13 is applied to a joint between the surface connection pin 2 of the SOP temporarily fixed to the printed board 4 and the printed board 4 from a nozzle 18 of a batch flow soldering apparatus (not shown).
To supply the molten solder 13 to the surface connection pins 2 of the SOP. In this manner, the molten solder 13 is
The printed circuit board 4 is moved so that the surface connection pins 2 come into contact with the jet wave surface 19 while supplying the molten solder to the surface connection pins 2, and then the molten solder is cooled to connect the printed circuit board 4 to the surface. Pin 2 is soldered. At this time, the printed circuit board 4 moves obliquely upward, and the molten solder 13 jetted from the nozzle 18 is moved.
Among them, the excess solder tends to escape in the direction opposite to the moving direction. In this way, when the printed circuit board is moved in the direction perpendicular to the longitudinal direction of the surface connection pins 2 and soldered, the longitudinal direction of the surface connection pins and the supply direction of the solder are perpendicular to each other. It becomes easy to occur and excess solder is easily separated from the surface connection pins 2. Therefore, even when the batch soldering is performed using the automatic batch flow soldering apparatus, a solder bridge is hardly generated between the surface connection pins 2.

On the other hand, as shown in FIG. 4 (c), when soldering is performed in a direction (B direction) along the longitudinal direction of the surface connection pins 2, jetting from the nozzle 18 is performed as shown in FIG. 4 (d). The melted solder 13 is jetted along the longitudinal direction of the surface connection pins 2. At this time, since the excess molten solder 13 has no escape place, the package body 1 is removed from the surface connection pins 2.
Excessive molten solder 13 is applied to the surface connection pins 2
Even when the printed circuit board 4 is detached from the solder, it is difficult for excess solder to be cut off from the surface connection pins 2. Therefore, a solder bridge is likely to occur in a portion 5 where excess solder cannot be cut.

As described above, when the surface connection pins of the surface mount electronic component and the printed circuit board are subjected to collective flow soldering, it is necessary to make it easy for excess solder to escape and for the solder to separate from the surface connection pins. However, in the case of a conventional surface mount electronic component in which surface connection pins are derived from four sides of a square package body such as a QFP, when the solder is moved in one direction to perform a batch flow process as shown in FIG. The A direction and the B direction occur simultaneously.

However, in the present invention, as shown in FIG. 1, all the input / output surface connection pins derived from the package body are arranged parallel to each other and in the same direction. The soldering direction can be supplied in the direction A shown in FIG. 4, that is, the direction perpendicular to the longitudinal direction of all the surface connection pins. However, peelback is likely to occur and solder bridges generated between the surface connection pins do not occur. Therefore,
The occurrence of solder bridges can be prevented without reducing the number of surface connection pins.

In order to prevent solder bridging in batch soldering, it is only necessary that all surface connection pins derived from the surface-mounted electronic component are arranged in parallel with each other and in the same direction. The sides to be formed are not limited to four sides, and the shape of the package body is not limited to a square but can be appropriately changed.

[0027]

As described above in detail, in the present invention, since all the plurality of surface connection pins derived from the package body of the surface mount electronic component such as the QFP are parallel to each other and face in the same direction. , Have a direction orthogonal to the longitudinal direction of all the surface connection pins. Therefore, when the surface-mounted electronic components are connected to the printed circuit board by batch flow soldering, all the surface connection pins can be passed in a direction orthogonal to the longitudinal direction, so that a solder bridge between adjacent surface connection pins occurs. Hateful. That is, the occurrence of solder bridges between adjacent surface connection pins can be prevented without impairing the high-density mounting of the fine-pitch surface connection pins.

[Brief description of the drawings]

FIG. 1 is a plan view showing a surface mount component according to an embodiment of the present invention.

FIGS. 2A and 2B are diagrams showing a configuration of a surface connection pin of the surface mount electronic component according to the embodiment of the present invention,
(A) is an enlarged plan view of a main part, and (b) is (a)
FIG.

FIG. 3 is a sectional view showing an automatic batch soldering apparatus.

FIG. 4 is a schematic diagram illustrating a relationship between a direction of batch flow soldering and surface connection pins.

FIG. 5 is a plan view showing an SOP.

FIG. 6 is a plan view showing a conventional QFP.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1; Package main body 1a; Edge 2; Surface connection pin 4; Printed circuit board 10; Automatic batch soldering device 11; Solder bath 12; Heater 13; Melt solder 15; 20; jet height (wave height) 21; thermocouple

Claims (6)

[Claims] 1. A package body having a polygonal shape and surface connection pins derived from the package body, wherein all the surface connection pins are parallel to each other and oriented in one direction,
A surface-mounted electronic component, wherein at least a part of the surface connection pins is inclined at an angle θ of less than 90 ° with respect to an edge of the package body from which the surface connection pins are led out. 2. The surface-mounted electronic component according to claim 1, wherein the package body forms a quadrangular rectangle, and the surface connection pins are derived from all four sides and face in the same direction. . 3. The surface-mounted electronic component according to claim 1, wherein the package main body has a quadrangular rectangle, and the surface connection pins are led out from only three sides and face in the same direction. 4. The package body according to claim 1, wherein the package body has a square shape, and an angle θ between an edge of the package body from which the surface connection pins are led and the surface connection pins is 45 °. 4. The surface-mounted electronic component according to any one of 3. 5. A package having a package body whose edge is formed by a curve, and surface connection pins derived from the package body, wherein all the surface connection pins are parallel to each other and face in one direction. And surface mount electronic components. 6. The surface-mounted electronic device according to claim 1, wherein a batch solder flow process is performed by passing the surface connection pins in a direction perpendicular to a longitudinal direction of the surface connection pins. parts.