JPH08181426A - Reflow soldering device and reflow soldering method - Google Patents

Abstract

PURPOSE: To provide a reflow soldering device and a reflow soldering method which enable economical and highly reliable soldering when mounting an especially large surface mounting type integrated circuit on a printed substrate. CONSTITUTION: In a hot air nozzle 15, a plate-like press part 15a is supported at four corners through a supporting part 15d and a spring 15e which are slidable in an insertion surface with the hot air nozzle 15. A projection part 15c is provided to almost a center of a lower surface of the press part 15a. A jet nozzle 17a is provided with a supporter 19 for supporting a printed substrate 11 from a lower surface. When the hot air nozzle 15 lowers for soldering, the press part 15a also lowers and brings an integrated circuit 12 to contact bonding to the printed substrate 11.

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 As a reflow soldering device of this type of device which has been conventionally used, a device having a structure shown in FIG. 4 is generally used. FIG. 4 is a partial sectional view of a conventional device, and FIG. 5 is a perspective view of a hot air nozzle. FIG. 6 is a perspective view of a surface mount PGA integrated circuit, and the integrated circuit comprises a package 42a and leads 42b. FIG. 7 is a side view showing a state in which an integrated circuit is attached to a printed circuit board (a).
Shows a normal state, and (b) shows a state in which the printed circuit 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.
An integrated circuit 42 is attached to a predetermined position of the printed circuit board 41 held by.

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.

As another conventional example, there is an apparatus or method for 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 was almost impossible to solder the surface mount PGA integrated circuit to a thin printed 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]

In the reflow soldering apparatus of the present invention, a hot air nozzle is provided with a press portion for crimping a lead of a surface mount type integrated circuit on the upper surface of a printed circuit board via a package of the integrated circuit. Have.

The pressing portion may be a square plate shape having four corners supported by the hot air nozzle through a supporting part that slides on a surface through which the hot air nozzle is inserted and a spring, or a cross-shaped plate shape. Good.

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.

Further, in the reflow soldering method of the present invention, the substantially central portion of the lower surface of the abutting portion of the lead of the printed circuit board is supported from below by the column, and the lead of the surface mounting type integrated circuit is the surface mounting type integrated circuit. A pressing portion provided in a hot air nozzle for ejecting hot air that contacts the upper surface of the package through the package is pressure-bonded to the contact surface with the printed circuit board.

[0015]

Function: The solder paste is printed on the required portion, the integrated circuit is attached to a predetermined position of the printed circuit board held by the support frame, and the printed circuit board with the integrated circuit is attached to the predetermined position of the reflow soldering device. Installed, the hot air nozzle surrounds the integrated circuit attachment portion of the printed circuit board to blow down the hot air of the inert gas to the cream solder portion. At that time, the press part supported by the hot air nozzle simultaneously descends, and the leads of the integrated circuit are pressure-bonded to the cream solder of the printed circuit board whose lower surface is supported by the pillars through the package.

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 portion of the press portion 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]

Embodiments of the present invention will now 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
It is composed of a jet nozzle 17a 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 reflow soldering device is installed at a predetermined position of the reflow soldering apparatus, and the lower surface of the printed circuit board 11 is raised to the bottom of the jet nozzle 17a.
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 jets of the hot air 16 and the high temperature oil 18 are 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 cream solder 13 is melted and soldered while crimping the integrated circuit 12 to the printed circuit board 11, warpage due to the temperature rise of the printed circuit board 11 can be prevented, and the cream solder 13 on the lead of the integrated circuit 12 can be prevented. It doesn't float. 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.

In the hot-air nozzle 15 of the second embodiment, a cruciform plate-shaped press portion 15b has a support part 15d and a spring 15 which are slidable at the four corners on the surfaces through which the hot-air nozzle 15 is inserted.
It is supported via e and. A convex portion 15c is provided on a contact surface of the press portion 15b with the integrated circuit 12.

Since the press portion 15b has a cross-shaped plate shape, the fluid resistance is smaller than that of the square plate-shaped press portion, and the flow of the hot air 16 blown out from the hot air nozzle 15 is less disturbed, so that the temperature of the soldering portion is uneven. Is less.

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, columns 19 for supporting the lower surface of the printed circuit board are provided independently.

[0031]

As described above, according to the present invention, the leads of the integrated circuit are pressure-bonded to the printed circuit board to melt and solder the cream solder, so that the warpage of the printed circuit board due to the temperature rise of the printed circuit board can be prevented. It is possible to solder easily.

In the case of using a plate-shaped press portion whose four corners are supported by the hot-air nozzle through the support component slidable on the insertion surface of the hot-air nozzle and the spring, the force of crimping is the spring. Can be adjusted to a desired state by selecting.

When the press portion according to the third aspect is a cross-shaped plate, the flow of the hot air blown from the hot air nozzle is less disturbed, so that the temperature unevenness of the soldering portion is reduced.

When the contact portion of the press portion with the package according to claim 4 is one point of the convex portion provided on the surface of the press portion facing the package, there is little resistance in the sliding direction with the package and the hot air nozzle. The influence on the blur of the package due to the blur at the time of descending 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 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 section 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 cross-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 mount PGA integrated circuit.

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

[Explanation of symbols]

 11 Printed Circuit Board 12 Integrated Circuit 13 Cream Solder 14 Support Frame 15 Hot Air Nozzle 15a Square Plate Press 15b Cross Plate Press 15c Convex 15d Support Part 15e Spring 16 Hot Air 17 Oil Tank 17a Jet Nozzle 18 High Temperature Oil 19 Strut 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 Strut

Claims (6)

[Claims] 1. A support frame for supporting a printed circuit board having a surface mount type integrated circuit attached to an upper surface thereof, a hot air nozzle surrounding the outer edge of the surface mount type integrated circuit and capable of moving up and down, and the printed circuit board capable of moving up and down. In a reflow soldering device consisting of a high temperature oil jet nozzle in which a pillar supporting the bottom surface of the integrated circuit is provided on the bottom surface, a lead of the surface mount type integrated circuit is provided on the upper surface of the printed circuit board to the hot air nozzle. A reflow soldering device having a press part for crimping via. 2. The reflow soldering device according to claim 1, wherein the press portion is a rectangular plate-like member, and the four corners of the press portion include a support component and a spring that are slidable on a surface through which the hot air nozzle is inserted. A reflow soldering device, which is supported by a hot air nozzle through the reflow soldering device. 3. The reflow soldering device according to claim 1, wherein the press portion is a cross-shaped plate, and four corners of the press portion are slidable on a surface through which the hot air nozzle is inserted, and a spring. A reflow soldering device, which is supported by a hot air nozzle via a. 4. The reflow soldering device according to claim 1, wherein a contact portion of the press portion with the package is provided substantially at a center of a surface of the press portion facing the package. A reflow soldering device characterized in that it is one point of a convex portion. 5. The reflow soldering device according to claim 1, wherein the integrated circuit is a surface mount PGA integrated circuit. 6. The hot air blown from the upper surface of the corresponding contact portion by the contact portion of the lead of the surface mount type integrated circuit which is in contact with the predetermined position of the upper surface of the printed circuit board on which the cream solder is printed at the predetermined position. And a reflow soldering method of soldering the lead and the printed circuit board by being heated by a jet of high temperature oil that contacts the lower surface of the contact part of the printed circuit board, the lead of the printed circuit board The lower surface of the contact portion is supported by a pillar from below, and the hot air blown by the leads of the surface-mounted integrated circuit is in contact with the upper surface of the package through the package of the surface-mounted integrated circuit. The reflow soldering method is characterized in that a pressing portion provided in a hot air nozzle for pressing is pressure-bonded to a contact surface with the printed circuit board.