JPH01306068A - Soldering method of electronic parts and soldering device used therein - Google Patents

Abstract

PURPOSE:To allow easy and sure coating of solder on the pads of a printed circuit board by coating the solder of a solder tank on said pads to build up the solder thereon at the time when the printed circuit board passes the solder tank. CONSTITUTION:The printed circuit board 6 with the pad part 7 to be soldered faced downward is passed in the solder tank in which the cream solder 10 is stored and which is provided with a pump 12 and a nozzle 13 in the central part. The cream solder 10 adsorbs on the pad part 7 and is build up thereon. This printed circuit board 6 is thereafter mounted on a prescribed X-Y table and the pattern surface thereof is previously recognized by a pattern recognition device. The flux is then coated in a prescribed pattern on the cream solder 10 sticking to the pad part 7. While FIC 8 is held adsorbed to a suction pad 3b, the FIC 8 is lowered and is correctly mounted on the printed circuit board 6 side. Hot air is blown to a pin terminal 8b and the cream solder 10 part on the lower side thereof to heat said part; thereafter, the cream solder is cooled to tentatively solder the FIC 8 side to the printed circuit board 6 side.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to flat package ICs (hereinafter referred to as FICs) in which a large number of pin terminals are protruded from the sides of a package part. This article relates to a soldering method for soldering electronic components onto a printed circuit board and a soldering device used in the soldering method.

[Conventional technology]

BACKGROUND ART Conventionally, a series of mounting operations for attaching and mounting FICs and the like on a printer 1 to a substrate using, for example, a robot has been automated, and the following methods are known as the operation method.

■ First, apply cream solder to the wiring pattern using a mask corresponding to the wiring pattern of the printed circuit board.

(2) Next, place the printed circuit board on the XY child table and check the position of the printed circuit board.

(2) Then, the FIC is mounted as an electronic component at a predetermined position on the printed circuit board.

(2) Thereafter, the printed circuit board with the FIC mounted thereon is passed through a reflow oven to be heated and then cooled, and the pin terminals of the FIC are soldered to the pin terminal attachment parts (hereinafter referred to as pads) on the pattern wiring side.

[Problem to be solved by the invention]

By the way, in recent years, as electronic components have become more densely packaged, the number of pin terminals on electronic components such as ICs has increased, and the dimensions and spacing of each pin terminal, as well as the dimensions and spacing of the pads on the printed circuit board to which they are attached, have also increased significantly. It's getting narrower. For this reason,
When using the above method, it is difficult to reliably apply cream solder to each pad portion, and there is a need for the development of a highly accurate, simple, and reliable application method for cream solder.

In addition, when using such a method, even if the FIC pin terminals are accurately positioned and mounted on the pads on the printed circuit board coated with cream solder, they may be damaged during subsequent transportation to a reflow oven, etc. Alternatively, there is a risk that the pin terminals may become misaligned until the solder, such as cream solder melting, solidifies. By the way, in such a case, the self-alignment effect caused by the surface tension when the solder melts can naturally align and correct the positional deviation to some extent, but even then, for FICs etc. that have a large number of miniaturized pin terminals, I can't expect much of an effect.

Furthermore, when using the above method, when the FIC, etc. is heated in a reflow oven, the pan cage of the FIC, etc. physically expands and changes due to the heat, but the parts inside the package are There is a risk that the heat may cause damage, or that moisture, gas, etc. mixed in and sealed in the package portion may destroy the pan cage portion due to its expansion force. Therefore, in order to effectively protect the package,
It is requested that the package part not be heated too much. Under these circumstances, there is a demand for the development of a method or means that can melt only the solder on the pad portion without exposing the pancage portion to high temperatures.

In view of the above-mentioned conventional circumstances, the present invention makes it possible to easily and accurately apply solder to pads on a printed circuit board even for electronic components such as FICs that have miniaturized pin terminals. , a method for soldering electronic components that can effectively prevent misalignment between the pad and pin terminal, and also protect the bar/7 cage part, and the soldering method used in the method. The purpose is to capture and provide equipment.

[Means to solve the problem]

That is, the method of soldering electronic components according to the present invention is to apply solder to pads on a printed circuit board while passing through a solder bath, apply solder to the solder on the pads of the printed circuit board, and apply flux to the solder on the pads of the printed circuit board. The electronic component is mounted so that the pin terminal is located on the pad to which flux and solder are attached, and the solder on which the pin terminal is mounted is excited with high frequency, and the package part is cooled while the electronic component is fixed. At the same time, the solder is heated.

Further, the soldering device of the present invention is a soldering device for attaching a pin terminal of an electronic component onto a solder pad of a printed circuit board, and the soldering device fixes the package side of the electronic component to the printed circuit board side. A cooling means for cooling the package side of the electronic component, and a heating means for heating the solder on the pad.

Further, the soldering apparatus of the present invention uses a ceramic 7-heater as a heating means.

Further, the soldering device of the present invention uses cold air that is cooled and sent out by the cooling action generated by the cooling means as the gas changes from compression to expansion.

Further, the soldering device of the present invention has a blocking wall for blocking the cold air sent from the cooling means and the heat generated from the heating means.

[Effect]

The soldering method of electronic components of this invention is such that when the printed circuit board passes through the solder bath, the solder from the solder bath is applied to the pads of the printed circuit board, and the solder is piled up. Solder can be applied accurately and reliably.

In addition, the method for soldering electronic components of the present invention is such that, prior to soldering the pin terminals of electronic components, the pin terminals and the solder portions on which the pin terminals are placed are slightly vibrated by high frequency. The pin terminals can be naturally aligned by greatly exerting the self-alignment effect generated by minute vibrations, and thereby the positional deviation of the pin terminals with respect to the pads can be effectively corrected.

Furthermore, the soldering method of this invention heats the pin terminals and melts the solder while forcibly cooling the package part of the electronic component, thereby reducing the heat of the package part during soldering work. It is possible to effectively prevent damage to objects.

Further, the soldering apparatus of the present invention is such that, with the pan cage part of the electronic component fixed to the printed circuit board side by the fixing means, the pin terminal is placed by the heating means while cooling the package part by the cooling means. The solder on the pads of the printed circuit board is heated and melted, and when soldering electronic components, it is possible to effectively prevent pin terminals from being misaligned, and also to effectively prevent thermal damage to the package part.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a soldering device used in the electronic component soldering method according to the present invention.
The main body 1 is connected via a cylinder rod 2a to a piston (circuit) inserted into a cylinder 2 provided at the tip of the arm (circuit) of the robot, and includes a fixing means 3, a cooling means 4, and a heating means. 5. In addition, the symbol 6 in the figure
7 is a printed circuit board positioned and placed on an XY child table (not shown), 7 is a pad provided on the printed circuit board 6, and 8 is an FIC with a large number of pin terminals 8b provided on all sides of a package part 8a. are shown respectively.

The fixing means 3 fixes and supports the FIC 8, which is an electronic component, on the side of the printer 1 and the substrate 6. In this embodiment, it is connected to a vacuum pump (not shown), and is operated by the negative pressure of the sucked air. In order to adsorb the FIC 8, an intake hole 3a is formed in the center portion. The fixing means 3 has a distal end expanded to form a suction pad 8b, and an intermediate portion thereof is a through hole 1a formed in the center of the main body 1.
is penetrated by. Further, this fixing means 3 has a protruding part 3C formed on its upper side, and the protruding part 3c is a slide chamber l formed in the slide hole 1a of the main body 1 and the slide hole J2.
An elastic force is always applied downward by the compression spring 9 in b. This fixing means 3 is connected to a piston (circuit) inserted into a cylinder (circuit) provided on the upper base end side or the tip end side of the robot arm, and is controlled by the pressure of the air flowing into the piston. It is designed to move up and down.

The cooling means 4 is a pin terminal 8b of the FIC 8 which is an electronic component.
This is to prevent the package part 8a of the FIC 8 from being destroyed or malfunctioning due to the heat when the solder is heated and melted when soldering the FIC to the pad 7 on the printed circuit board 6. In this case, the cooling section is connected to a blowing pump (circuit) and is composed of a plurality of small hole ICs formed in the vertical direction inside the main body 1. That is, the cooling means 4 of this embodiment is cooled and cooled as the air that has been forcibly sent out from the blower pump to the pore IC rapidly expands when it is discharged from the lower side of the main body 1. It looks like it's blowing out. In addition, in order to efficiently blow the cold air blown from the cooling means 4 onto the vano gauge part 8a of the FIC8, which is an electronic component, and to effectively prevent the pin terminal 8b side of the FIC8 from being cooled, a As shown in FIG. 2, a blocking wall 1d is provided in a protruding manner.

As shown in FIG. 2, the heating means 5 applies heat from above to the pin terminal 8b placed on the pad 7 portion of the printed circuit board 6 via the cream solder 10 to melt the cream solder 10. The pin terminal 8b is soldered to the pad 7 portion using the ceramic heater 5 embedded in the leg portion le provided on the lower outer peripheral edge side of the main body 1 in this embodiment.
a is used. Note that this ceramic heater 5a
The heat generated from the main body leg 1e is transferred to the pore 1.
A heat insulator 11 is disposed between the ceramic heater 5a and the pore IC so that the air passing through the ceramic heater 5a is not heated.

Next, a method for soldering electronic components according to the present invention will be explained with reference to FIGS. 2 to 8.

(2) Pass the printed circuit board 6 with the pad 7 to be soldered facing downward through the solder tank 14 with the cream solder 10 and the pump 12 and nozzle 13 provided in the center (see FIG. 3). Note that it is desirable that the cream solder 10 used at this time be one with as high a viscosity as possible.

(2) Then, the cream solder 10 is adsorbed to the pad portion 7 formed of copper foil or the like and soldered (see FIG. 4).

■ Thereafter, the printed circuit board 6 coated with the cream solder 10 is placed on a predetermined XY child table enclosure), and the pattern surface of the placed printed circuit board 6 is recognized by a pattern recognition device (not shown). I'll keep it.

(2) Next, flux 15 is applied in a predetermined pattern onto the cream solder 10 adhered to the pad 7 using a conventional quantitative applicator (circle) or the like (see FIG. 5).

(2) After similar pattern recognition is performed for the FIC to be mounted, the soldering device of the previous embodiment is used to operate the piston in the cylinder and the vacuum pump. Then, 1 liter was placed on the suction pad 3b of the fixing means 3.
C8 is lowered while adsorbed, and with each pin terminal 8b properly aligned with the pad 7 side, the FIC 8 is correctly mounted on the printed circuit board 6 side (see FIG. 6).

■ Next, using a local heater 16 as shown in FIG.
Blow hot air into the 0 parts to heat them.

■ Here, there may be a positional shift between the pin terminal 8b of the FIC8 and the pad 7, but even if there is a positional shift, the cream solder is forcibly vibrated slightly.
In order to use the self-alignment effect generated at this time to correct the positional deviation, a conventional high-frequency generator (circuit) irradiates the cream solder 10 with high-frequency waves (see FIG. 8). Thereafter, the cream solder is cooled and the FICB side is temporarily soldered to the printed circuit board 6 side.

■ In this way, after the pin terminal 8b is correctly positioned on the pad 7 on the printed circuit board 6 side and temporarily soldered, the soldering device used in the previous embodiment is used again to finish the soldering. (See Figure 2).

In the soldering method of this embodiment, the cream solder is locally heated using a local heater as the sixth step, but this step is not particularly necessary.

〔effect〕

As explained above, if the method of soldering electronic components of the present invention is used, the solder in the solder bath will adhere to the pads on the board side of each print board 1 by passing the solder bath through the printed circuit board, and the solder will be soldered. Since the solder is stacked, solder can be easily and reliably applied to pads on which electronic components are mounted, even if there are many pin terminals.

Moreover, if the method of the present invention is used to solder electronic components,
Since high-frequency waves are used to minutely vibrate the solder before it solidifies, creating a strong self-alignment effect, even if the pin terminal placed on the solder is misaligned, The positional deviation can be effectively corrected.

Furthermore, if the electronic component G soldering method of the present invention is used, the buff gauge part of the electronic component is cooled when the electronic component is soldered, so the heat generated during solder melting is used to cool the package. Trouble such as damage to internal parts or destruction of the package can be effectively prevented.

In addition, if the soldering device according to the present invention is used, the package part of the electronic component to be soldered is fixedly supported by the fixing means, so that it does not shift positionally with respect to the printed circuit board side. can effectively prevent the time position shift.

Furthermore, if the soldering device according to the present invention is used, the soldering of electronic components can be done by forcibly cooling the pan cage part of the electronic component, which is easily destroyed by heat, by the cooling means during the soldering operation. It is possible to effectively prevent destruction of electronic components during the process.

Further, if the soldering device according to the present invention is used, since ceramic is used for the heater used as the heating means, adhesion of solder, etc. can be prevented, and a highly reliable device can be obtained.

Furthermore, if the soldering device according to the present invention is used, the configuration effectively utilizes the physical phenomenon in which the gas is cooled as the gas changes from compression to expansion as a cooling means, so it is possible to use the soldering device according to the present invention. It is possible to achieve miniaturization without the need for such a complicated mechanism.

Furthermore, if the soldering device according to the present invention is used, the cold air sent from the cooling means and the heat generated from the heating means are blocked by the shielding wall, so cooling and heating can be performed efficiently. Effective.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the soldering device according to the present invention, FIG. 2 is a cross-sectional view of the main part of the soldering device shown in FIG. 1, and FIGS. 3 to 8 are electronic components according to the present invention. This is a process diagram showing the soldering method. 14...Solder tank. 6...Printed circuit board. 7...Pad. 10... (cream) solder. 15...Flux. 8b...Pin terminal. 8a...Package part. 8...Electronic components (FIC). Applicant NEC Home Electronics Co., Ltd. Agent Patent Attorney Masu 1) Takeo 788a La 6 Get 1 Approval! ■ 68 no G 8!

Claims (5)

[Claims] 1. Apply solder to the pads on the printed circuit board while passing through the solder bath, apply solder to the solder on the pads of the printed circuit board, and position the pin terminals on the pads to which the flux and solder are applied. The electronic component is mounted with an electronic component, and the solder on which the pin terminal is mounted is excited at high frequency, and the solder is heated while cooling the package part with the electronic component fixed. How to solder. 2. A soldering device for attaching pin terminals of an electronic component onto solder pads of a printed circuit board, the device comprising: a fixing means for fixing a package side of the electronic component to a printed circuit board side; and a fixing means for fixing a package side of the electronic component to a printed circuit board side; A soldering device comprising: a cooling means for cooling the pad; and a heating means for heating the solder on the pad. 3. 3. The soldering apparatus according to claim 2, wherein a ceramic heater is used as the heating means. 4. 3. The soldering apparatus according to claim 2, wherein the cooling means uses cold air that is cooled and sent out by a cooling effect generated as the gas changes from compression to expansion. 5. 5. The soldering apparatus according to claim 2, further comprising a shielding wall for blocking cold air sent from the cooling means and heat generated from the heating means.