JP2658929B2 - Reflow soldering apparatus and reflow soldering method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow soldering apparatus for soldering a lead, which is provided on a lower surface of a package of a surface mount type integrated circuit, to a printed circuit board, and particularly to a large surface mount type PGA integrated circuit. And a reflow soldering method.

[0002]

2. Description of the Related Art A conventionally used have been reflow soldering apparatus of this type, generally those of the configuration shown in FIG. 4 was used. FIG. 4 is a partial cross-sectional view of a conventional device,
FIG. 5 is a perspective view of the hot air nozzle. Figure 6 shows the surface mount type P
1 is a perspective view of a GA integrated circuit, in which an integrated circuit is package 4;
2a and a lead 42b. FIGS. 7A and 7B are side views showing a state where the integrated circuit is attached to the printed board, and FIG. 7A shows a normal state, and FIG. 7B shows a state in which the printed board is warped.

The reflow soldering apparatus includes a support frame 44 for supporting a printed circuit board 41 on which a surface-mounted integrated circuit 42 is abutted, and a hot-air nozzle capable of moving up and down around the outer edge of the surface-mounted integrated circuit 42. An oil tank 47 and a jet nozzle 47a of high-temperature oil 48 having a column 49 that can move up and down and that supports the printed circuit board 41 from below are provided on the bottom surface.

In the conventional reflow soldering method, a cream solder 43 is printed on a required portion and a supporting frame 44 is printed.
The integrated circuit 42 is attached to a predetermined position on the printed circuit board 41 held by the printer.

A support frame 44 to which the integrated circuit 42 is attached is attached.
The printed board 41 supported by the support 4 is installed at a predetermined position of the reflow soldering apparatus, and the support 4 is provided upright on the bottom surface of the jet nozzle 47a in which the lower surface of the printed board 41 is raised.
After being supported by 9, the hot air nozzle 45 descends around the contact portion of the integrated circuit 42 of the printed circuit board 41, and the hot air nozzle 45 descends, and hot air 46 of high-temperature inert gas is blown onto the cream solder 43. The high temperature oil jetted from the jet nozzle 47a communicating with the oil tank 47 comes into contact with the lower surface of the printed circuit board 41 to melt the cream solder 43 and perform soldering.

[0006] As another conventional example, there is an apparatus or method for performing soldering only with hot air without using high-temperature oil.

Further, in order to improve the reliability of soldering, a method has been proposed in which a recess for receiving a lead is provided in a printed circuit board as disclosed in Japanese Patent Application Laid-Open No. 3-220792.

[0008]

However, in the prior art, the temperature of the printed circuit board 41 also increases due to the heating for melting the cream solder 43, and the printed circuit board 41 is likely to be warped due to temperature imbalance. When the size of the integrated circuit was small, it was not a problem. However, when the size of the integrated circuit was increased as in the case of the surface mount type PGA integrated circuit, some of the leads 42b floated from the cream solder 43 as shown in FIG. There was a problem that soldering failure occurred. In particular, it has been almost impossible to solder a surface-mounted PGA integrated circuit to a thin printed circuit board.

In order to prevent the occurrence of such defects, there has been proposed a method of providing a concave portion for receiving a lead in the printed circuit board as described above, but there is a disadvantage that the manufacturing cost of the printed circuit board is increased.

An object of the present invention is to provide a reflow soldering apparatus capable of overcoming the above-mentioned disadvantages and performing economical and highly reliable soldering.

[0011]

Reflow soldering apparatus of the present invention, in order to solve the problem] has provided a lead surface mount integrated circuits on the upper surface of the printed circuit boards in a hot air nozzle for crimping over the package of the integrated circuit The press section has a hot air nozzle and
Through a support part and a spring that slide on the insertion surface of
It has a square plate shape whose corners are supported by hot air nozzles .

[0012] The pressing portion may be a ten-shaped plate shape the four corners via the supporting part and a spring to slide in the insertion plane of the hot air nozzle is supported on the hot air nozzles.

Further, a contact portion of the press portion with the package is
It may be one point of the protrusion provided on the surface of the press section facing the package.

[0014]

[0015]

A cream solder is printed on a required portion, an integrated circuit is attached to a predetermined position of a printed circuit board held by a support frame, and the printed circuit board on which the integrated circuit is attached is placed at a predetermined position of a reflow soldering apparatus. The hot air nozzle descends around the integrated circuit contact portion of the printed circuit board in order to blow hot air of an inert gas onto the cream solder portion. At this time, the press portion supported by the hot air nozzle is simultaneously lowered, and the lead of the integrated circuit is pressed through the package to the cream solder of the printed circuit board whose lower surface is supported by the support.

In a plate-shaped press portion having four corners fixed to the hot-air nozzle via a spring and a supporting member that slides on the hot-air nozzle insertion surface, the pressing force is adjusted by the spring.

In the case of a cruciform plate, the flow of the hot air blown out from the hot air nozzle is hardly disturbed, so that the temperature unevenness of the soldered portion is reduced.

Further, the contact part of the press part with the package is
In the case of one point of the convex portion provided substantially at the center of the surface of the press section facing the package, the resistance in the sliding direction with the package is small, and the influence on the package due to blurring when the hot air nozzle descends is reduced. . When the lower surface of the printed circuit board is in contact with the circulating high-temperature oil, the temperature of the cream solder rises quickly and becomes more uniform.

[0019]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a partial sectional view of a first embodiment of the present invention, and FIG. 2 is a perspective view of a press section of the first embodiment.

The reflow soldering apparatus according to the first embodiment of the present invention comprises a support frame 14 for supporting a printed circuit board 11 on which a surface-mounted integrated circuit 12 is abutted, and an outer edge of the surface-mounted integrated circuit 12. A hot air nozzle 15 that can be raised and lowered surrounding the portion, and a high-temperature oil 18 that has a column 19 that can be raised and lowered and that supports the printed circuit board 11 from the bottom surface and that stands on the bottom surface
And an oil tank 17.

Inside the hot air nozzle 15, a rectangular plate-like press portion 15a is supported via a supporting part 15d slidable at four corners on a surface through which the hot air nozzle 15 is inserted and a spring 15e. At the approximate center of the contact surface of the press portion 15a with the integrated circuit 12, a convex portion 15c is provided.

In the reflow soldering method according to the first embodiment of the present invention, a cream solder 13 is printed on a required portion, and an integrated circuit 12 is provided at a predetermined position on a printed circuit board 11 held by a support frame 14. I have.

The support frame 14 on which the integrated circuit 12 is mounted
The printed circuit board 11 supported on the printed circuit board 11 is installed at a predetermined position of the reflow soldering apparatus, and the support column 1 erected on the bottom surface of the jet nozzle 17a in which the lower surface of the printed circuit board 11 rises.
9, the hot air nozzle 15 descends around the contact portion of the integrated circuit 12 of the printed circuit board 11, and hot air 16 of high-temperature inert gas is blown from the lowered hot air nozzle 15 onto the 13 parts of the cream solder. The high-temperature oil 18 jetted from the jet nozzle 17a communicating with the oil tank 17 contacts the lower surface of the printed circuit board 11, and the cream solder 13
Is melted and soldering is performed. After the soldering is completed, the jet of the hot air 16 and the high-temperature oil 18 is stopped to cool the printed circuit board 11, and after the cooling is completed, the hot air nozzle 15 is raised and the jet nozzle 17a is lowered.

When the hot air nozzle 15 descends, the press portion 12 also descends, and the convex portion 15c contacts the upper surface of the package of the integrated circuit 12. When the hot air nozzle 15 further descends to a predetermined position, the convex portion 15c Is the tip of the lead of the integrated circuit 12 by the repulsive force of the spring 15e.
1 is pressed on the upper surface. At this time, the lower surface of the printed board 11 is supported by the columns 19.

Since the melting and soldering of the cream solder 13 are performed while the integrated circuit 12 is pressed against the printed circuit board 11, warpage due to a rise in the temperature of the printed circuit board 11 can be prevented. Does not cause floating. Since the pressure bonding is continued until the cooling is completed, good soldering is possible.

The contact portion of the press section with the package may be flat. However, as in this embodiment, one point of the convex portion provided substantially at the center of the surface of the press section facing the package is used to make the flat section. The resistance in the sliding direction between the contact portion and the package is smaller than in the case where the contact is made, and the influence of the shake when the hot air nozzle is lowered on the shake of the package is reduced. FIG. 3 is a perspective view of a press unit according to a second embodiment of the present invention.
The second embodiment is the same as the first embodiment except for the structure of the press section, and thus the description of the other structures and operations will be omitted.

The hot-air nozzle 15 of the second embodiment has a cross-shaped plate-shaped press portion 15b, a supporting part 15d slidable at four corners on the insertion surface of the hot-air nozzle 15, and a spring 15b.
e. A convex portion 15c is provided on a contact surface of the press portion 15b with the integrated circuit 12.

Since the pressing portion 15b has a cruciform plate shape, the fluid resistance is smaller than that of a square plate-shaped pressing portion, and the flow of the hot air 16 blown out from the hot air nozzle 15 is less disturbed. Is reduced.

In the first and second embodiments of the present invention, the lower surface of the printed circuit board is heated with high-temperature oil. However, soldering may be performed only with hot air. In this case, a support 19 for supporting the lower surface of the printed circuit board is provided independently.

[0031]

As described above, according to the present invention, since the solder of the cream solder is melted and soldered by pressing the leads of the integrated circuit to the printed circuit board, the warpage of the printed circuit board due to the temperature rise of the printed circuit board can be prevented. a solderable Ri can and Do, sliding in the insertion plane of the hot air nozzle shown in claim 1
Hot air nozzles at the four corners through possible support parts and springs
When using a plate-shaped press section supported by a
Wearing force adjusted by spring selection to desired condition
It becomes possible .

[0032]

[0033] When the press section shown in claim 2 was cruciform plate is unevenness of the temperature of the soldering portion is reduced because it is less disturbing the flow of the hot air blown from the hot air nozzles.

The billing contact portion between the press portion of the package shown in claim 3, in the case of one point of the convex portion provided on the package and the surface facing the press section, the slip direction of the resistance is small hot air nozzles of the package The influence on the shake of the package due to the shake at the time of falling is reduced.

The technique of the present invention has made it possible to solder a surface-mounted PGA integrated circuit to a thin printed circuit board, which was almost impossible with the prior art.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a perspective view of a press unit according to the first embodiment of the present invention.

FIG. 3 is a perspective view of a press unit according to a second embodiment of the present invention.

FIG. 4 is a partial sectional view of a conventional device.

FIG. 5 is a perspective view of a conventional hot air nozzle.

FIG. 6 is a perspective view of a surface-mounted PGA integrated circuit.

FIG. 7 is a side view showing a state where an integrated circuit is mounted on a printed board. (A) shows a normal state. (B) shows a state in which the printed board has warped.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Printed board 12 Integrated circuit 13 Cream solder 14 Support frame 15 Hot air nozzle 15a Square plate-shaped press part 15b Cross-shaped plate-shaped press part 15c Convex part 15d Support part 15e Spring 16 Hot air 17 Oil tank 17a Jet nozzle 18 High temperature oil 19 Post 41 Printed circuit board 42 Integrated circuit 42a Package 42b Lead 43 Cream solder 44 Support frame 45 Hot air nozzle 46 Hot air 47 Oil tank 47a Jet nozzle 48 High temperature oil 49 Column

Claims (3)

(57) [Claims] 1. A support frame for supporting a printed circuit board on which a surface-mounted integrated circuit is mounted on an upper surface, a hot-air nozzle capable of moving up and down around an outer edge of the surface-mounted integrated circuit; A jet nozzle of high-temperature oil having a support standing on the bottom surface for supporting the lower surface from above, and the print
The surface mount type integrated circuit leads are integrated on the upper surface of the substrate.
The hot air nozzle to crimp through the circuit package
And a press portion provided in the reflow soldering apparatus, wherein the press portion has a square plate shape, and four corners of the press portion
A support component and a spur that can slide on the insertion surface of the hot air nozzle
It is supported by the hot air nozzle through the ring.
Reflow soldering equipment. 2. A plug having a surface-mounted integrated circuit on its upper surface.
A support frame for supporting the lint substrate, and the surface mount type
A hot air nozzle that can be raised and lowered around the outer edge of the integrated circuit;
A support that can be lowered and supports the printed circuit board from the bottom
A high-temperature oil jet nozzle standing on the surface and the print
The surface mount type integrated circuit leads are integrated on the upper surface of the substrate.
The hot air nozzle to crimp through the circuit package
Reflow soldering consisting of a press part provided on the
In the pressing device, the press section is a cross-shaped plate, and the four corners of the press section
And a support member slidable on the surface through which the hot air nozzle passes.
That it is supported by the hot-air nozzle
Characteristic reflow soldering equipment. 3. The refill according to claim 1, wherein :
In the flow soldering apparatus, a contact portion of the press section with the package is formed by the press section.
Convex part provided at the approximate center of the surface of the
Reflow soldering device characterized by being one point
Place.