JPH09206926A - Inert atmosphere producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make up a stable atmosphere by an inert gas in non-contact soldering or the like using a laser beam. SOLUTION: The inert gas such as nitrogen or the like introduced from an inlet 1b into an annular blowing pipe 1 is not immediately discharged from blowing holes 1a and the gas pressure within the blowing pipe 1 is risen because blowing holes la are perpendicularly arranged to the inlet 1b. The inert gas is about uniformly blot from many blowing holes 1a, arranged with about equal intervals facing to a processing area A, into the processing area A by this pressure. The gas existing within the processing area A from the first is ejected from gaps g1, g2 arranged between an upper and lower shielding plate 3a, 3b forming the processing area A and the annular blowing pipe 1, and replaced by the inert gas. Furthermore, the stable inert atmosphere within the processing area A is always secured by continuously feeding the inert gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inert atmosphere creating apparatus for creating an atmosphere of an inert gas in, for example, non-contact soldering using a laser beam.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
For example, there is one described in the following literature. Document 1; Japanese Patent Application Laid-Open No. 5-347476 Document 2; Japanese Patent Application Laid-Open No. 6-77638 The laser reflow device described in Document 1 requires an inert atmosphere in a device that irradiates a laser beam for soldering. The inert gas such as nitrogen gas heated by the heater was directly blown from the nozzle to the soldering location. Further, the laser soldering device described in Reference 2 covers a soldering portion requiring an inert atmosphere with a transparent case, and an inert gas is introduced into the transparent case from one place on the transparent case by an introduction pipe. Was injected to make the inside of the transparent case an inert atmosphere, and the soldering spot was irradiated with a laser beam from the outside of the transparent case.

[0003]

However, the conventional inert atmosphere creating apparatus has the following problems.
Since the inert gas is injected into the processing region for soldering or the like by one nozzle in the laser reflow device of Document 1 and by one introduction pipe in the laser soldering device of Document 2, the shape of the processing region It was difficult to make the gas flow uniform due to the influence of the material to be processed. For this reason, the concentration of the inert gas became unstable, and some of the active gas such as oxygen remained. Since soldering is usually performed at a high temperature of 180 ° C. or higher, oxidation of solder and solder joints occurs particularly in an atmosphere in which oxygen is present. This causes non-wetting (small contact area of solder joint) and solder balls (solder leaks into a spherical shape from the solder joint), which is not possible in terms of soldering quality. . If non-wetting occurs, it may cause a failure such as poor connection or insufficient connection strength, and if a solder ball occurs, it may cause a short-circuit failure. The present invention provides an inert atmosphere creating apparatus that solves the instability of an inert atmosphere as a problem of the above-mentioned conventional technique.

[0004]

In order to solve the above-mentioned problems, a first aspect of the present invention is an apparatus for producing an inert atmosphere, which is arranged so as to face each other so as to form a processing region of an inert atmosphere by an inert gas. There is a gap between the first and second shield plates, a plurality of supply pipes for supplying the inert gas to the processing region, and at least one of the shield plates between the first and second shield plates, and And an annular blowing pipe arranged so as to surround the processing region. In addition, a plurality of inlets for introducing the inert gas supplied from the supply pipes into the outlet pipes are provided in the outlet pipes, and the inlets that are substantially perpendicular to the inlets and face the processing region. A plurality of blow holes for blowing the inert gas in the blow pipe almost uniformly are formed. In the second invention, the first
The blow-out pipe of the invention of the present invention has a substantially rectangular annular shape, the injection ports are formed at the four corners of the rectangle, and the plurality of blow-out holes are formed at substantially uniform intervals on the surface of the blow-out pipe on the side of the processing region. There is. In the third invention, the first and second shielding plates of the first or second invention are formed of a light transmissive material.

According to the first, second and third aspects of the invention, since the inert atmosphere creating apparatus is constructed as described above, the inert atmosphere is formed as follows. Since the inlet and the outlet formed in the outlet pipe are perpendicular to each other, the inert gas supplied from the supply pipe through the inlet into the outlet pipe is
Immediately, the air is not discharged from the blowout hole, but fills the blowout pipe once,
Increase the pressure in the blow pipe. Since the pressure of the inert gas in the blowing pipe is transmitted to the inside of the pipe almost uniformly, the inert gas is blown out to the processing region from the plurality of blowing holes substantially uniformly. The gas existing in the processing region surrounded by the annular blow-out pipe and the first and second shield plates is pushed out from the gap between the blow-out pipe and the shield plate by the inert gas blown out from the blow-out holes,
The processing area is filled with an inert gas. Further, by continuing the supply of the inert gas, the processing area always becomes a stable inert atmosphere.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially cutaway perspective view of an inert atmosphere producing apparatus showing an embodiment of the present invention.
This inert atmosphere generating device is, for example, a square tube having a rectangular hollow cross section of about 16 mm on a side of about 300 m.
The blow-out pipe 1 has a rectangular ring shape of m × 400 mm and is formed so as to surround a processing region A that requires an inert atmosphere. On the inner surface 1-1 of the blow-out pipe 1 facing the processing area A, blow-out holes 1a for blowing out an inert gas such as nitrogen gas are uniformly arranged at intervals of about 4 mm. Further, at the four corners of the lower surface 1-2 of the blow-out pipe 1, there are provided inlets 1b for introducing an inert gas into the blow-out pipe. In this way, the blowout hole 1a and the inlet 1b are arranged so as to be perpendicular to each other. A plurality of supply pipes 2 for supplying an inert gas into the pipes from an inert gas supply device (not shown) are connected to the plurality of inlets 1b. In addition, in the upper part and the lower part of the processing area A surrounded by the blow-out pipe 1, the upper surface 1-3 and the lower surface 1-2 of the blow-out pipe 1 are respectively 5
Transparent first and second shielding plates (eg, upper and lower shielding plates) 3 made of glass or the like with gaps g1 and g2 of about mm
a and 3b are arranged. FIG. 2 is a cross-sectional view showing a usage state of the inert atmosphere creating apparatus of FIG. With reference to this figure, the soldering work performed using this inert atmosphere creating apparatus will be described.

First, the printed wiring board 4 on which the solder has been supplied and the components have been mounted is placed in the processing area A surrounded by the blow-out tube 1, the upper shielding plate 3a and the lower shielding plate 3b. Next, an inert gas such as nitrogen gas is supplied to the blow-out pipe 1 from the injection port 1b through the supply pipe 2 from the inert gas supply device. Since the inlet 1b and the blowout hole 1a are provided perpendicular to each other, the inert gas supplied from the supply pipe 2 through the inlet 1b in the direction of the arrow x is directly blown to the blowout hole 1a of the blowout pipe 1. There is no such thing. When the inert gas introduced into the blow-out pipe 1 exits from the blow-out hole 1a, it is necessary to change the flow direction as indicated by an arrow y. Therefore, the blow pipe 1
The inert gas introduced therein is not immediately discharged from the blowout hole 1b but once fills the blowout pipe 1 to increase the gas pressure inside the blowout pipe 1. In this way, the gas pressure inside the blow-out pipe 1 rises almost uniformly due to the inert gas supplied from the inlet 1b. The inert gas in the blowout pipe 1 having a high pressure is blown out almost uniformly from the plurality of blowout holes 1 a formed toward the processing area A, and is uniformly supplied to the processing area A. In this way, since the inert gas is supplied from the periphery of the processing area A, the oxygen gas or the like originally present in the processing area A is mounted on the printed wiring board 4 arranged in the processing area A or mounted. The blow-out pipe 1 is made by the blown out inert gas without being affected by the shape of parts.
Is expelled through the gaps g1 and g2 between the upper and lower shield plates 3a and 3b, and is replaced with the inert gas.

According to the experiment, for example, in the case of the apparatus having the above-mentioned configuration, when the supply amount of the inert gas is 20 l / min,
About 1 minute after the start of the supply, the processing area A is almost completely filled with the inert gas. Further, it has been obtained from the experimental results that inside the processing region A, which is 50 mm or more away from the inner surface 1-1 having the blowout hole 1a of the blowout pipe 1, the change of the gas concentration due to the flow of the inert gas is extremely small. As described above, after the processing area A is filled with the inert gas, the transparent upper shielding plate 3 is continuously supplied while further supplying the inert gas.
A laser beam 7 is irradiated from an optical fiber 6 to the soldering portion 5 from the outside of a to perform soldering. Like this
The inert atmosphere creating device of the present embodiment has the following (1)-
There are advantages such as (3).

(1) In the annular blow-out pipe 1 surrounding the processing area A, since the inert gas inlet 1b and the blow-out hole 1a are provided so as to be perpendicular to each other, the inert gas supplied from the inlet 1b. Causes the gas pressure in the blowout pipe 1 to rise almost uniformly, and is blown out almost uniformly from the blowout holes 1a around the work area A. Therefore, a stable inert atmosphere can always be secured in the work area A. (2) Since the blowing tube 1 formed in a rectangular ring shape is used by using the rectangular tube having the rectangular cross section, it is possible to easily manufacture the inert atmosphere creating device according to the size of the required processing area A. (3) Since the upper shielding plate 3a is formed using a light-transmissive material, the laser beam 7 can be efficiently irradiated to the soldering points 5. The present invention is not limited to the above embodiment, and various modifications can be made. Examples of this modification include the following (a) to (g).

(A) In the above-described embodiment, the example of using the inert atmosphere creating apparatus has been described by using the example of soldering, but the invention is not limited to soldering, and may be applied to a ceramic sealing step, a can seal step, etc. Can be used. (B) The size of the blow-out pipe 1 of the above embodiment is based on the assumption of a general printed wiring board, but the size is not limited to this size and is adjusted to the size of the processing area A that is actually required. be able to. (C) The shape of the blow-out pipe 1 in FIG. 1 is a quadrangular ring, but is not limited to a quadrangle, and may be a circle, an ellipse, a triangle, or another polygonal ring. (D) The cross section of the outlet pipe 1 in FIG. 1 has a rectangular shape,
The tube is not limited to a rectangle, and may be a tube having a circular cross section. (E) The inlet 1b and the supply pipe 2 in FIG. 1 are arranged at the four corners of the quadrangular ring-shaped blow-out pipe 1, but the present invention is not limited to this, and may be adjusted according to the shape and size of the blow-out pipe 1. It can be arranged as appropriate. (F) The inlet 1b and the supply pipe 2 in FIG. 1 are arranged on the lower surface 1-2 of the blow-out pipe 1, but not limited to this, and they are arranged on the upper face 1-3 of the blow-out pipe 1. You can also
It can also be arranged on both the upper surface 1-2 and the lower surface 1-3. (G) Although both the upper shield plate 3a and the lower shield plate 3b in FIG. 1 are arranged so as not to be in close contact with the blow-out pipe 1, either one may be arranged in close contact with the blow-out pipe 1. .

[0011]

As described above in detail, according to the first aspect of the invention, the inert gas injection pipe is formed so that the inert gas inlet and the outlet are perpendicular to each other.
The inert gas introduced from the inlet into the blow-out pipe is not immediately discharged from the blow-out hole, but once fills the blow-out pipe to increase the pressure in the blow-out pipe. Since the pressure of the inert gas in the blow-out pipe is almost evenly transmitted into the pipe, the inert gas can be blown out almost uniformly from the plurality of blow-out holes surrounding the processing area, and a stable inert atmosphere can be created in the processing area. Can be created. According to the second invention, since the blowing pipe formed in a substantially rectangular annular shape is used, the effect of the first invention is obtained, and the structure of the blowing pipe is simple, and the blowing pipe is adapted to the required processing area. A space with an inert atmosphere can be easily created. According to the third invention, the first and second shielding plates are made of a light-transmissive material.
The effect of the second invention can be obtained, and the object to be processed housed in the processing area can be efficiently irradiated with a laser beam or the like from the outside.

[Brief description of drawings]

FIG. 1 is a perspective view of an inert atmosphere creation device showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the inert atmosphere creating device of FIG. 1 in a use state.

[Explanation of symbols]

 A Processing area g1, g2 Gap 1 Blow pipe 1a Blow hole 1b Injection port 2 Supply pipe 3a Upper shield plate 3b Lower shield plate

Claims (3)

[Claims] 1. A first shielding plate and a second shielding plate, which are arranged so as to face each other so as to form a processing region of an inert gas atmosphere, and a plurality of supplies for supplying the inert gas to the processing region. A pipe, an annular blow-out pipe disposed between the first and second shield plates and having a gap with at least one of the shield plates and surrounding the processing region; A plurality of inlets for introducing the inert gas supplied from each of the supply pipes into the outlet pipe, and an inert gas in the outlet pipe that is substantially perpendicular to the inlets and faces the processing region. An inert atmosphere creating device, comprising: a plurality of blow holes formed in the blow pipe so as to blow substantially uniformly. 2. The blow-out pipe has a substantially rectangular ring shape,
2. The inert atmosphere creating apparatus according to claim 1, wherein the inlets are formed at four corners of the rectangle, and the plurality of outlets are formed on the surface of the outlet pipe on the side of the processing region at substantially uniform intervals. 3. The inert atmosphere creating apparatus according to claim 1, wherein the first and second shielding plates are made of a light transmissive material.