JPH05243451A - Solder dipping apparatus - Google Patents

Abstract

PURPOSE:To suppress a solder bridge generated when leads of a printed circuit board or an LSI package are covered with solder by using a solder dipping apparatus. CONSTITUTION:A board holder 10 which mounts a module board 9 is supported to a board holder 4 through a shaft 11. After the holder 4 is moved down to dip leads 13 of the board 9 in a molten solder tank 1, the holder 4 is lifted to pull up the leads 13 from the tank 1, and a pulley 12 attached to the shaft 11 is driven to rotate the holder 10 at a high speed, thereby separating to remove excess melted solder adhering to the leads 13 by a centrifugal force in a solder dipping apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder dipping technique,
In particular, the present invention relates to a technique effective when applied to solder dipping treatment of leads of a printed wiring board or an LSI package.

[0002]

2. Description of the Related Art Conventionally, it has been used as a lead for a module board in which leads are arranged in a staggered pattern on one side of a printed wiring board (also called a Zimp module board) or a pin insertion type LSI package such as DIP (Dual In-line Package) In contrast,
Surface treatment is performed by the solder dipping method.

[0003]

However, in recent years Zi
Since the gap between the leads of the mp module board is being narrowed down to about 0.15 mm, a solder residue (so-called solder bridge) occurs between the leads in the conventional solder dipping method.

As a countermeasure, attempts have been made to suppress the occurrence of solder bridges by adjusting the speed at which the module substrate is pulled up from the molten solder bath and the angle between the module substrate and the solder liquid surface. That is not the case.

Therefore, an object of the present invention is to provide a technique capable of suppressing the occurrence of solder bridges when solder is applied to the leads of a printed wiring board or an LSI package by a solder dipping method.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0007]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

In the solder dipping device of the present invention, a holding portion for holding a printed wiring board or an LSI package is pivotally supported by a holder via a shaft, and the holder is lowered from above the molten solder bath so that the printed wiring board or After dipping the leads of the LSI package into the molten solder bath, the holder is raised to raise the printed wiring board or the LSI.
Pull the package leads out of the molten solder bath, then
By driving a pulley attached to the shaft to rotate the holding portion at a high speed, excess molten solder attached to the leads is separated and removed by centrifugal force.

[0009]

According to the above-mentioned means, after the molten solder is deposited on the leads, the holding portion is rotated at a high speed to separate and remove the excess molten solder deposited on the leads by the centrifugal force. It is possible to avoid problems such as occurrence of a solder bridge and adhesion of excessively thick solder to the lead surface.

[0010]

[Embodiment 1] Hereinafter, the structure of a solder dipping device according to an embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, above the molten solder bath 1 and the flux bath 2 installed adjacent thereto,
For example, a substrate holder 4 which is moved in a desired direction by a robot equipped with an articulated arm 3 is installed.

Molten solder 5 is stored in the molten solder bath 1 and flux 6 is stored in the flux bath 2. Further, a flywheel 8 that rotates at high speed by driving a motor 7 is installed near the molten solder bath 1.

FIG. 2 is a perspective view of the substrate holder 4, FIG. 3 is a front view of the same, and FIG. 4 is a side view of the same with a part thereof cut away.

A substrate holder 10 for holding the module substrate 9 is rotatably supported by a leg of the substrate holder 4 via a shaft 11. A pulley 12 is attached to one end of the shaft 11.

The module board 9 is, for example, a so-called Zimp module board in which a large number of leads 13 extend in a zigzag pattern from one side of a printed wiring board, and a plurality of LSI packages are mounted on both surfaces of the module board 9 to form a memory module. It is used as such.

As shown in FIG. 4, the module substrate 9 is
Inserted in the groove 14 formed on the lower surface of the substrate holding portion 10,
For example, it is held by the wire 15 for preventing falling. At this time, the leads 13 of the module substrate 9 are exposed below the substrate holder 10.

The module substrate 9 is provided with a groove 14 by hand from the side of the substrate holder 10 or by using a robot hand.
Inserted in. When the module substrate 9 is taken out from the groove 14 after the solder dipping work is completed, the same operation is performed.

Next, a solder dipping method using the solder dipping device constructed as described above will be described with reference to FIGS. 1 and 5.

First, as shown in FIG. 1, after mounting the module substrate 9 on the substrate holding portion 10 axially supported by the legs of the substrate holder 4 by the above-described method, the articulated arm 3 is driven to drive the substrate holder. 4 is lowered from above the flux bath 2, and the leads 13 of the module substrate 9 are immersed in the flux 6.

Subsequently, the substrate holder 4 is raised to pull up the leads 13 from the flux tank 2, and then the substrate holder 4
Is moved horizontally above the molten solder bath 1 and the leads 13 of the module substrate 9 are immersed in the molten solder 5 in the same manner.

Next, as shown in FIG. 5, after the lead 13 is pulled out from the molten solder bath 1, before the molten solder attached to the lead 13 and the module substrate 9 is solidified, the substrate holder 4
Is rapidly moved to bring the pulley 12 into contact with the flywheel 8 and rotate the substrate holding portion 10 and the module substrate 9 mounted thereon at a high speed (for example, about 2000 rpm), whereby excessive melting attached to the leads 13 is melted. Separate and remove the solder by centrifugal force.

At this time, by controlling the rotation speed and rotation time of the module substrate 9, the amount of solder remaining on the surface of the lead 13 can be optimized.

The flywheel 8 is rotated in advance before it comes into contact with the pulley 12. By doing so, the pulley 12 starts to rotate at the moment when it comes into contact with the flywheel 8, so that it is possible to prevent the molten solder attached to the leads 13 and the module substrate 9 from solidifying before the substrate holding portion 10 rotates. it can.

[0024]

[Embodiment 2] Next, the construction of the essential parts of a solder dipping device according to another embodiment of the present invention will be described with reference to FIG.

The solder dipping device according to the second embodiment has a rotary arm 17 having, for example, four arms 16, and each of the arms 16 has a substrate holder 4 having the same structure as that of the first embodiment at the tip thereof. Installed.

The rotary arm 17 is rotatable in a horizontal plane. Further, near the rotary arm 17, a flywheel 8 that rotates at high speed by driving the motor 7 is installed. Although illustration is omitted, a molten solder bath or a flux bath is installed below the substrate holder 4 attached to the tip of the arm 16.

In order to deposit the solder on the leads 13 of the module substrate 9 by using the solder dipping device configured as described above, for example, the flux tank installed below the substrate holder 4 is raised to remove the leads 13. Immerse in flux.

In this case, instead of the means for raising the flux tank, a small inner tank 18 is installed inside the flux tank 2 as shown in FIG. 7, and the inner tank 18 is raised. Good. By doing so, the height of the liquid surface of the flux can be made constant.

Then, after lowering the flux tank or the inner tank 18, the rotary arm 17 is rotated by 90 degrees in a horizontal plane to horizontally move the substrate holder 4 on which the flux applying process is completed above the molten solder tank. .. Then, for example, the molten solder bath or the inner bath installed therein is elevated to immerse the lead 13 in the molten solder.

Next, the molten solder bath or the inner bath is lowered. At this time, the flywheel 8 installed in the vicinity of the rotary arm 17 moves toward the substrate holder 4 and comes into contact with the pulley 12, so that the substrate holding portion 10 and the module substrate 9 mounted thereon are rotated at high speed. Thus, the excess molten solder attached to the leads 13 is separated and removed by the centrifugal force.

In the second embodiment, the rotary arm 17 may be vertically moved instead of the means for vertically moving the flux tank or the inner tank 18.

Although the invention made by the present inventor has been specifically described based on the above embodiment, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

In the second embodiment, the case where the inner bath installed inside the molten solder bath or the flux bath is moved up and down is illustrated, but the molten solder in the molten solder bath (or the flux in the flux bath) is jetted. It may be configured to be lifted to a predetermined height by.

In the above-mentioned embodiment, the case where the present invention is applied to the solder dipping of the module substrate has been described. However, by changing the design of the substrate holder and the substrate holding portion, Z
It can also be applied to solder dipping of IP and other LSI packages.

[0035]

The effects obtained by the typical ones of the inventions disclosed in this application will be briefly described as follows.
It is as follows.

According to the solder dipping device of the present invention, the solder dipping method is applied to a printed circuit board or an LSI package having a narrow lead pitch by separating and removing excess molten solder deposited on the leads by centrifugal force. Even in this case, it is possible to suppress the occurrence of solder bridges.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a solder dipping device that is an embodiment of the present invention.

FIG. 2 is a perspective view showing a substrate holder.

FIG. 3 is a front view showing a substrate holder.

FIG. 4 is a partially cutaway side view showing a substrate holder.

FIG. 5 is a diagram showing an overall configuration of a solder dipping device.

FIG. 6 is a diagram showing a configuration of a main part of a solder dipping device according to another embodiment of the present invention.

FIG. 7 is a front view showing a configuration of a flux tank.

[Explanation of symbols]

 1 Molten Solder Tank 2 Flux Tank 3 Articulated Arm 4 Board Holder 5 Molten Solder 6 Flux 7 Motor 8 Flywheel 9 Module Board 10 Board Holding Section 11 Shaft 12 Pulley 13 Lead 14 Groove 15 Wire 16 Arm 17 Rotary Arm 18 Inner Tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Nakamura 15 Asahidai, Moroyama-cho, Iruma-gun, Saitama Pref. Inside Hitachi Tobu Semiconductor Co., Ltd.

Claims (6)

[Claims] 1. A solder dipping device for depositing a predetermined amount of solder on a lead of a printed wiring board or an LSI package, wherein a holding portion for holding the printed wiring board or the LSI package is attached to a holder via a shaft. After pivotally supporting, the holder is lowered from above the molten solder bath to immerse the leads of the printed wiring board or LSI package in the molten solder bath, and then the holder is raised to lead the printed wiring board or LSI package leads. Is pulled up from the molten solder bath, and then the pulley attached to the shaft is driven to rotate the holding portion at a high speed. 2. The solder dipping device according to claim 1, wherein the holding portion is rotated at a high speed by bringing the pulley into contact with a flywheel arranged near the molten solder bath. 3. The solder dipping device according to claim 1, wherein the holder is moved by using an articulated arm. 4. A solder dipping device for depositing a predetermined amount of solder on a lead of a printed wiring board or an LSI package, wherein a holding portion holding the printed wiring board or the LSI package is attached to a holder via a shaft. Along with supporting the shaft, the holder is provided with a plurality of arms, is attached to a rotary arm that is rotatable in a horizontal plane, and a molten solder bath arranged below the rotary arm is raised or the rotary arm is lowered. After immersing the leads of the printed wiring board or the LSI package in the molten solder bath, the molten solder bath is lowered or the rotary arm is raised, and then the pulley attached to the shaft is driven to hold the holding portion. A solder dipping device, characterized in that it is configured to rotate at high speed. 5. The solder dipping device according to claim 4, wherein the holding portion is rotated at a high speed by bringing the pulley into contact with a flywheel arranged near the molten solder bath. 6. The solder dipping device according to claim 4, wherein an inner tank movable up and down is provided inside the molten solder tank.