JPH0749154B2 - Hot air solder melting device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solder melting apparatus that uses hot air as a heat source for removing or mounting a flat pack IC soldered to a printed circuit board.

(Prior Art) In response to the recent demand for high-density mounting, electrical components P and P ', such as semiconductor integrated circuits, have lead pieces r, r, r ... From the side surface of the package as shown in FIG. Are extended in parallel to form a flat pack. Since this flat-packed electric component can be surface-mounted by soldering on the surface of the printed circuit board without passing through a socket, it is possible to effectively use the surface of the printed circuit board and improve the mounting density. It has a great effect.

However, when soldering to the board, or when it becomes necessary to replace the mounted flat pack IC due to a failure or change in specifications, melt the solder of all lead pieces connected to the printed board at the same time. There is a problem that it cannot be removed unless it is used.

Therefore, the hot air generator H containing the suction pad K communicating with the negative pressure source in the nozzle N formed in conformity with the shapes of various flat pack electric parts P and P'as shown in FIG.
After the flat pack IC is adsorbed and fixed to the suction pad K by using, the hot air generator H is lowered to the circuit board, and hot air is blown from the nozzle N to melt the solder on the board.

However, since the suction pad K is usually made of an elastic material such as silicon rubber, when the electric component is pressed against the circuit board, the suction pad is elastically deformed to cause a displacement, which may cause a connection error. In addition to the above, there is a problem that the suction pad is easily deteriorated because it is exposed to the solder melting temperature.

(Object) The present invention has been made in view of such a problem, and an object of the present invention is to provide a hot-air solder melting apparatus having accurate positioning without using a suction pad and high reliability. Especially.

(Structure) Therefore, details of the present invention will be described below based on illustrated embodiments.

1 and 2 each show an embodiment of the present invention, in which reference numeral 1 is a hot air generator main body, and one end of the hot air generator main body communicates with a pressure source (not shown). Inlet
3a, and a plurality of heat-generating wires 3d housed in a heat-resistant cylinder 3c having a discharge port 3b formed at the other end, in this embodiment, three cylindrical heaters 3, 3, 3 are provided as discharge ports 3b, 3b. , 3b are arranged and housed so as to face the center line, and on the center line, one end is connected to a nozzle 6 to be described later, and the other end is connected to a suction pipe 4 which is connected to a negative pressure source. The main body 1 is fixed to the elevating mechanism 5 and can be moved up and down relatively to the circuit board. 6
Is a nozzle which is a feature of the present invention. At the lower end of the funnel portion 7 that is airtightly connected to the discharge ports 3b, 3b, 3b of the hot air generator 1, the tip end is made slightly larger than the outer circumference of the IC package. The shaped cylindrical body 8 is connected, and a partition member 9 to be described later is fixed to the tip of the cylindrical body 8 to form outlets 10, 10, 10, 10.

FIG. 3 shows one embodiment of the nozzle, in which the inner surface side corresponds to the peripheral surface shape of the flat pack IC, and the outer surface side is provided with the air outlets 10, 10, 10, 10 having a constant gap. The wall portions 9a, 9a, 9a, 9a to be formed and a space 11 which is regulated to a height at which the lead piece r is exposed in contact with the surface of the package and which is airtightly connected to the tip of the suction tube 4 in the central portion. The partition member 9 including the stepped portion 9b to be formed is joined at the four corners of the tubular body 8, and the four outlets 10, 10, 10 are provided between the surfaces of the wall portions 9a, 9a, 9a, 9a and the inner surface of the tubular body 8. , 10 are formed. In the figure, reference numeral 9c designates a connecting hole for attaching and detaching airtightly to the suction pipe, and 20
Shows a chuck mechanism which is connected to a rod 31 which is always urged upward by a spring to detachably fix the nozzle 20 to the lower end of the hot air generator main body 1.

In this embodiment, when the suction pipe 4 is connected to the negative pressure generation source and the heaters 3, 3 and 3 are connected to the gas supply source and the nozzle 6 is attached to the lower end of the main body 1, the tip of the suction pipe 4 is partitioned. It is airtightly joined to the connection hole 9c of the member 9. Inserting the flat pack IC to be soldered in this state (Fig. 4),
The flat pack IC has its four peripheral surfaces regulated by the wall portions 9a, 9a, 9a, 9a of the partition member 9 and the surface thereof by the step portion 9b.
The negative pressure of the vacant chamber 11 located on the upper surface is received and held in the partition member 9, and only the lead piece r is fixed in a state of facing the outlets 10, 10, 10, 10.

At this stage, the lifting mechanism 5 is operated to operate the flat pack IC.
Is lowered to a predetermined position on a circuit board (not shown), the flat pack IC is restricted in the surface direction by the wall portions 9a, 9a, 9a, 9a at the tip of the nozzle 6 and in the vertical direction by the step portion 9b, and the lead piece r is predetermined. Accurately positioned in place.

When the electric power and the gas are supplied to the heaters 3, 3 and 3 at the stage of completing such preparation, the discharge ports of the heaters 3, 3 and 3 are
Hot air F is jetted from 3b, 3b, 3b. The hot air merges in the funnel portion above the nozzle 6 located in the vicinity to generate a vortex, and the hot air moves toward the outlets 10, 10, 10, 10 while stirring each other, and the wall portion of the partition member 9 is formed. Air outlets 10, 10, 10, 10 regulated by the surfaces of 9a, 9a, 9a, 9a and the inner surface of the cylindrical body 8.
Gushes from. As a result, only the lead pieces r, r, r ... Are selectively heated, and the solder on the substrate facing this is melted. In this process, the partition member 9 receives hot air and its temperature rises.
Since the vacant chamber 11 formed between the IC and the IC is in a decompressed state, the vacant chamber 11 exerts a good heat insulating action and suppresses the temperature rise of the flat pack IC as low as possible.

If the power supply to the heaters 3, 3, 3 is stopped when the solder is completely melted, the gas will not be heated
The lead pieces r are cooled by jetting from 10, 10, 10. When the solder is solidified in this way, the negative pressure source is cut off and the hot air generator 1 is raised, so that the nozzle 6 can be removed without applying an external force to the flat pack IC that has been soldered.

On the other hand, when removing the flat pack IC soldered to the circuit board, after the tip of the nozzle 6 is mounted to be removed, hot air is sent to melt the solder fixing the flat pack IC. When the hot air generator main body 1 is moved upward by applying a negative pressure to the empty chamber 11 at the time of melting, the flat pack IC is sucked into the partition member 9 and separated from the substrate.

In the above-described embodiment, the case where the leads are provided on the four sides of the IC package has been described as an example, but in the case where the leads are provided only on the opposite two sides (the sixth (B) As shown in FIG. 5, a nozzle 30 in which the outlets 31, 31 are formed only in the exposed portion of the lead piece r is prepared and mounted on the hot air generator main body 1,
By reducing the number of heaters to be operated, it is possible to supply the hot air of a heat quantity suitable for this type of flat pack IC, save the power consumption of the heater, and set the best solder melting conditions. Become.

Further, in the above-described embodiment, the nozzle tip portion is configured by joining two separate members, the outer cylinder and the partition member, but an injection moldable material such as heat resistant plastic or ceramic material is used. It can also be integrally formed.

(Effects) As described above, in the present invention, the inner wall has a step portion that contacts the peripheral surface of the semiconductor package, and also has a step portion that contacts the surface of the semiconductor package so as to expose the lead portion of the package. A partition member that is connected to a negative pressure source that supplies a negative pressure to a space formed by the semiconductor package and a discharge port of the hot air generator that is detachable and that forms a constant gap with the outer peripheral surface of the partition member. Since the outer cylinder that constitutes the outlet for selectively supplying hot air to the lead portion is provided, not only the semiconductor package can be accurately positioned by the partition member, but also the space formed by the partition member and the semiconductor package is improved. It is possible to selectively supply hot air to the lead portion while blocking the heat generated when the solder is melted.

[Brief description of drawings]

FIG. 1 is a sectional view of an apparatus showing an embodiment of the present invention, FIG. 2 is a top view of the same apparatus, and FIGS. 3 (a) and (b) are nozzles used in the same apparatus, respectively. FIG. 4 is a perspective view and a sectional view showing an embodiment, FIG. 4 is a sectional view showing a working state of the above apparatus, FIG. 5 is a perspective view showing another embodiment of the nozzle, and FIGS. Are perspective views showing examples of flat-packed electric parts, and FIG. 7 (a).
(B) is a perspective view showing an example of a conventional hot-air solder melting apparatus, and a sectional view showing the nozzle structure thereof. 1 ... Main body of hot air generator, 3 ... Heater 6 ... Nozzle, 8 ... Cylindrical body 9 ... Partitioning member, 9a ... Wall part 9b ... Step part, 10, 31 ... Outlet port P, P ' ...... Flat pack IC

Claims (1)

[Claims] 1. An inner wall is in contact with a peripheral surface of a semiconductor package and has a step portion in contact with a surface of the semiconductor package so as to expose a lead portion of the package, and the step portion and the semiconductor package are formed. A partition member connected to a negative pressure source for supplying a negative pressure to the space and a discharge port of the hot air generator, and a fixed gap is formed between the partition member and the outer peripheral surface of the partition member. A hot-air solder melting apparatus comprising: an outer cylinder that constitutes an outlet for selectively supplying hot air.