JP3316515B2 - Cover for heater rail - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a heater rail in which a base material is conveyed and heated when a semiconductor pellet is bonded to a base material such as a lead frame using a solder, and more particularly to an improvement in a hole provided in a cover. The present invention relates to a cover structure capable of keeping the atmosphere in a tunnel as a non-oxidizing atmosphere while minimizing the entrance of outside air.

[0002]

2. Description of the Related Art An example of a conventional heater rail will be described. FIG. 2A is a plan view thereof, and FIG. 2B is a side view showing a cross section taken along line AA in FIG. 2A. In the heater rail 1, a heat block 2 having a U-shaped cross section is arranged with its concave opening facing upward. A heater (not shown) is embedded in the heat block 2, and a dish-shaped adapter rail 4 covering almost the entire surface is disposed on the bottom surface of the concave portion 3 with the concave surface facing downward. Further, the heat block 2 is provided with a gas flow path from a gas introduction port 5 provided on the outer surface toward the bottom surface of the concave portion. Therefore, a space formed by the adapter rail 4 and the bottom surface of the concave portion of the heat block 2 serves as a tank 6 for storing the introduced gas. A cover plate 7 is attached to the upper surface of the heat block 2 so as to cover the recess 3, and the recess 3 forms a tunnel 3 a.

When assembling a semiconductor pellet (not shown) to a lead frame (not shown), the lead frame (not shown) is heated while being transported on the adapter rail 4 and solder (not shown) or semiconductor Pellets (not shown) are supplied and assembled. At this time, an inert gas such as nitrogen gas is introduced from the gas inlet 5 to prevent oxidation of the lead frame and the solder. The introduced inert gas fills the tank 6 and is blown into the tunnel 3a from gas outlets 4a provided around the adapter rail 4, and is discharged from the entrance and the outlet of the tunnel 3a as a non-oxidizing atmosphere.

[0006] To a good atmosphere in a tunnel at a flow rate of as little inert gas can, tunnel 3
order to a opening it is possible to be a small area, is an opening necessary minimum mosquito bar <br/> over plate 7, solder supply hole 7a, the holes 7b for expanding stirring solder melted, the semiconductor A pellet supply hole 7c for supplying pellets is provided. When a lead frame feed mechanism is provided in the tunnel 3a
, The holes provided in the cover plate 7 need only those described above, but the tunnel 3a is increased, the cover plate 7
Distance from to the lead frame becomes deeper, the semiconductor pellet mechanism or an obstacle to faster supply of the <br/> of which is complicated, is also performed to convey the lead frame from the outside. In that case includes a carrier claw hole 7d as shown in FIG. 2 (A). The hole 7d for the transport claw is also made as small as possible .
Its transport nail this Yuku send a lead frame in the Square over M o <br/> Deployment of the semiconductor device every one minute. In these places holes also discharged of including inert gas, the outer air tunnel 3
A flow rate must be provided so as not to flow back into a.

[0005] However, as shown in FIG.
For example, when the solder supply hole 7a is open, an inert gas is blown out from the hole 7a to prevent the inflow of outside air as shown by a solid line arrow. Although it is not a convection action, it can be estimated that the outside air is taken in as indicated by the broken line arrow, and there is a place where the oxygen concentration in the tunnel 3a cannot be sufficiently reduced. In view of this, the present applicant has previously provided a screen-like member 28 at the end of the hole 7a as shown in FIG. A proposal is made to take it out with an active gas (solid arrow). The screen-like member 28 preferably surrounds the opening in the form of a chimney. However, even if a part is inevitably missing for the purpose of the opening, there is a certain effect.

[0006]

However, when a partition member according to Japanese Patent Application No. 9-189519 is provided in the portion of the pellet supply hole 7c so as to surround the opening in a chimney shape, the semiconductor pellet is held in and out by vacuum suction. The operation path of the pellet transport mechanism becomes longer, which hinders speeding up of the chip bonder. In particular, since the pellet transport mechanism moves in and out of the pellet supply hole 7c at a high speed, the outside air is apt to be taken in, and it is necessary to make the chimney higher than the other parts. This further hinders the high-speed operation. Accordingly, the present invention provides a heater rail cover in which the inflow of outside air is reduced without hindering the high-speed operation of the device.

[0007]

According to the present invention, a tunnel is formed by covering a concave portion of a heat block having a U-shaped cross section, and a base material is conveyed in the tunnel. A heater rail cover to be heated,
The heater rail cover has an opening for accessing the base material for bonding the semiconductor pellet to the base material, and a cover plate and a hood are provided around the opening.
To form a space surrounded by
While introducing a neutral gas, and surrounding the opening.
A cover for a heater rail is provided, wherein a lit is formed and a gas curtain made of a non-oxidizing gas is blown up from the slit in a direction perpendicular to an opening surface.
According to the above configuration, the thereby preventing wraparound of outside air into the tunnel by gas curtain, even if <br/> things in and out of the apertures does not inhibit the movement. In addition, the outside air attempting to enter him to those of the Soviet Union, there is also action to be washed out by the mosquito Tengasu. Gas curtain may be provided so as to surround the opening, as only side things and out, the parts are missing only may be arranged Te member partition. Element,
Opening like this, as the opening for supplying the semi-conductor pellet is particularly suitable to the location where the object is out of the high-speed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. In this embodiment, the present invention is applied to a portion corresponding to the pellet supply hole 7c of the conventional device shown in FIG. The heat block 2 is not different from the conventional apparatus shown in FIG. FIG. 1A is a perspective view thereof, and FIG. 1B is a side view showing a cross section taken along line AA in FIG. 1A. This heater rail cover 20
Has a structure in which a hood 25 is attached to a cover plate 27.

The cover plate 27 has a solder supply hole (not shown), a hole for stirring and spreading the melted solder (not shown), and a pellet supply hole 27c for supplying semiconductor pellets as in the prior art.

The hood 25 is provided with a pellet supply hole 25a aligned with the pellet supply hole 27c of the cover plate 27.
And a slit 25b so as to surround the pellet supply hole 25a. And, it is mounted on the upper surface of the cover plate 27 and forms a substantially airtight space 30 with the cover plate 27 except for the slit 25b. A gas introduction pipe 25c connected to the space 30 is provided on a side surface of the hood 25.

The heater rail cover 20 forms a tunnel by covering the recess opening of the heat block having a U-shaped cross section as in the conventional case. When assembling a semiconductor pellet (not shown) to a lead frame (not shown), the lead frame (not shown) is heated while being transported in a tunnel, and solder (not shown) or semiconductor pellet (not shown) is used. (Not shown) Supply and assemble. At this time, a non-oxidizing gas such as an inert gas such as nitrogen gas or a reducing gas to which hydrogen is added is introduced into the tunnel to prevent oxidation of the lead frame and the solder. Semiconductor pellets (not shown) are supplied through a pellet supply hole 31 formed by a pellet supply hole 27c of the cover plate 27 and a pellet supply hole 25a of the hood 25 matched with the hole. Pellet supply hole 3
From 1, part of the inert gas supplied into the tunnel is blown out as indicated by the solid line arrow to prevent outside air from entering the tunnel.

Then, a non-oxidizing gas such as an inert gas whose pressure is adjusted independently of the inside of the tunnel is introduced into the gas introducing pipe 25c , and fills the space 30 to fill the slit 25b.
Blows up from the gas curtain. Then, the gas curtain than being provided close to the edge of the pellet feed hole 31 to prevent the outside air is entrained into the tunnel from the pellet supply holes 31.

The gas curtain also has a function of cleaning and removing the outside air which is brought when the pellet transport mechanism (vacuum suction nozzle) holds the semiconductor pellets and enters the pellet supply hole 31 at high speed.

According to the above embodiment, the gas curtain is provided so as to surround the pellet supply hole 31. However, the gas curtain is provided only on the side through which the pellet transport mechanism passes when entering and exiting, and the rest is provided with a screen member. It is also possible to surround the pellet supply hole 31 together.

As described above, the present invention is effective when applied to a hole into which a high-speed material enters, such as a pellet supply hole, but is applicable to other holes such as a solder supply hole. It is.

[0016]

As described above, according to the present invention,
Since a gas curtain is provided at the end of the hole provided in the cover to prevent outside air from being drawn in from the hole, even if something goes in and out of the hole, the high-speed operation is not hindered. In addition, the non-oxidizing atmosphere in the tunnel of the heater rail can be secured by washing and removing the outside air that is taken in by the one entering the hole at high speed.

[Brief description of the drawings]

FIG. 1A is a perspective view of a heater rail cover using an embodiment of the present invention. FIG. 1B is a side view showing a cross section taken along line AA.

FIG. 2A is a plan view of a conventional heater rail. FIG. 2B is a side view showing a cross section taken along line AA.

FIG. 3 is a cross-sectional view illustrating a state in which outside air flows backward from a hole in a conventional cover plate.

FIG. 4 is a cross-sectional view showing a state in which a screen member is disposed as a countermeasure;

[Explanation of symbols]

 20 Cover for heater rail 25b Slit 31 Pellet supply hole (opening)

Claims (4)

(57) [Claims] 1. A heater rail cover which covers a concave portion of a heat block having a U-shaped cross section and forms a tunnel, in which a base material is conveyed and heated in the tunnel, wherein the heater rail cover is a semiconductor. A device having an opening for accessing the base material for bonding pellets to the base material, wherein a cover plate and a hood are provided around the opening.
To form a space surrounded by
While introducing a neutral gas, and surrounding the opening.
A heater rail cover comprising a gas curtain made of a non-oxidizing gas which forms a lit and blows up from the slit in a direction perpendicular to an opening surface. 2. The heater rail cover according to claim 1, wherein said gas curtain surrounds said opening. 3. The heater rail cover according to claim 1, wherein the gas curtain is arranged so that a part of the periphery of the opening is partially cut off, and a screen-like member is arranged in the cut-out part. 4. The heater rail cover according to claim 2, wherein the opening is an opening for supplying a semiconductor pellet.