JP2000332401A - Method of cooling soldered product, soldered product cooling apparatus and soldering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method and apparatus for cooling a work to be soldered, whereby the work can be cooled quickly. SOLUTION: An ultrasonic atomizer 12 is provided for feeding finely atomized mist to a work to be soldered, immediately after soldering. The atomizer 12 has an ultrasonic oscillator 15 disposed at the bottom of a liq. tank 13 for finely atomizing a liq. 18 in the liq. tank 13. The liq. 18 uses demineralized water. The liq. temp. in the tank 13 is held at a set temp. by a thermo module 16 disposed at the lower side of the tank 13. A gas barrier forming piping 31, for forming a gas barrier over the entire circumstance of the tank 13, is disposed on the inner side surface of the tank 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cooling an object to be soldered, which cools an object to be soldered immediately after soldering, a cooling device for the object to be soldered, and a soldering apparatus.

[0002]

2. Description of the Related Art Conventionally, when a printed circuit board to be soldered is cooled after soldering, air cooling by a cooling fan is generally used in the atmosphere.

On the other hand, from the viewpoint of global environmental protection in recent years, soldering using so-called lead-free solder in which lead has been removed from solder has been performed. Soldering in an inert gas atmosphere such as that described above is employed.

[0004] In the soldering of this type of lead-free solder, since the residual oxygen concentration must be kept low by an inert gas atmosphere, the soldering is performed in an inert atmosphere chamber. In both the soldering and the reflow soldering, there is a problem in cooling the printed circuit board after the soldering.

[0005] For example, a cooling fluid such as nitrogen gas cooled is supplied to the atmosphere in the inert atmosphere chamber. If the supply amount of the cooling fluid is too large, the pressure changes in the inert atmosphere chamber. As a result, a constant residual oxygen concentration in the chamber cannot be maintained.

On the other hand, even if the cooling fan is provided outside the inert atmosphere chamber which does not affect the residual oxygen concentration in the chamber, the printed circuit board cannot be rapidly cooled.

There is also a method of cooling the inert atmosphere chamber itself. However, since the cooling is performed only by convection in the inert atmosphere chamber, the printed circuit board cannot be rapidly cooled.

If the printed circuit board after soldering cannot be rapidly cooled, for example, in a Sn-Ag-Bi (tin / silver / bismuth) lead-free solder, the solder composition segregates due to gradual cooling. As shown in (2), a soldering defect due to a fillet lift-off phenomenon in which the solder fillet F peels off from the land portion L of the printed circuit board P occurs.

[0009]

As described above, conventionally,
In both the jet flow soldering and the reflow soldering, when supplying an inert gas into the inert atmosphere chamber to maintain a constant low oxygen concentration atmosphere, print the cooled inert gas after soldering. The substrate is cooled by spraying it while allowing a certain degree of change in the oxygen concentration in the atmosphere. However, the amount of inert gas is limited because the residual oxygen concentration in the chamber must be kept constant. Only a small amount of heat can be taken for the amount of heat, and rapid cooling required to suppress the fillet lift-off phenomenon is difficult,
There is a need for a method suitable for cooling a printed circuit board immediately after soldering in an inert atmosphere chamber.

The present invention has been made in view of the above points, and provides a method and apparatus for cooling an object to be soldered, which can rapidly cool the object to be soldered, and hardly affects the residual oxygen concentration in a chamber. It is another object of the present invention to provide a soldering apparatus capable of rapidly cooling an object to be soldered.

[0011]

According to the first aspect of the present invention, an object to be soldered is cooled by supplying fine atomized mist to the object immediately after soldering. It is a cooling method.

When the finely atomized mist comes into contact with the object to be soldered immediately after soldering, the mist removes the latent heat of vaporization from the high-temperature object to be soldered. Suppress the fillet lift-off phenomenon.

According to a second aspect of the present invention, the object to be soldered according to the first aspect is a printed circuit board, and a finely atomized mist is selectively supplied to at least one of a lower surface and an upper surface of the printed circuit board. To be soldered.

Then, the lower surface, the upper surface, or both surfaces of the printed circuit board immediately after the soldering is rapidly cooled by mist as required.

According to a third aspect of the present invention, there is provided an object having a holding means for holding an object to be soldered and a mist supply device for supplying a fine mist to the object to be soldered. This is a soldering object cooling device.

When the mist supplied from the mist supply device comes into contact with the soldered object, the mist removes the latent heat of vaporization from the high-temperature object, so that the object is rapidly cooled. Thus, the fillet lift-off phenomenon is suppressed.

According to a fourth aspect of the present invention, the mist supply device according to the third aspect includes a liquid tank containing a liquid and an ultrasonic vibrator for finely atomizing the liquid in the liquid tank. This is a cooling device for the soldering object.

Then, a fine, low-temperature mist is produced from the liquid in the liquid tank by an ultrasonic vibrator.

According to a fifth aspect of the present invention, there is provided an apparatus for cooling an object to be soldered, wherein the liquid according to the fourth aspect is deionized water.

Since the deionized water is easy to generate and is a water having a stable property from which ions have been removed, the particle diameter when atomized finely is small and uniform.

According to a sixth aspect of the present invention, the liquid tank according to the fourth or fifth aspect has a hole opened at the bottom, and the ultrasonic vibrator is provided below the hole and at the periphery of the hole. This is a cooling device for the object to be soldered, which is provided in a liquid-tight manner through the fitted packing.

Since the liquid tank and the ultrasonic vibrator can be separated via the packing, cleaning of the liquid tank is easy, and management and maintenance of the ultrasonic vibrator are also easy.

According to a seventh aspect of the present invention, there is provided the cooling apparatus for the object to be soldered according to any one of the fourth to sixth aspects, further comprising a thermo module for maintaining a liquid temperature in the liquid tank at a set temperature. is there.

By keeping the temperature of the liquid in the liquid tank at the set temperature by the thermo module, a mist that is finely atomized is always produced under optimum temperature conditions even when the external temperature condition changes.

According to an eighth aspect of the present invention, there is provided the cooling apparatus for the object to be soldered according to any one of the fourth to seventh aspects, wherein the gas barrier is provided on the inner peripheral surface of the liquid tank and extends over the entire circumference of the liquid tank. Is provided with a gas-barrier forming pipe that forms

The finely atomized mist is kept in a limited area so as to be confined in a gas barrier formed over the entire circumference of the liquid tank by a gas barrier forming pipe, and is compact. A cooling region is formed by mist.

According to a ninth aspect of the present invention, there is provided a preheater for preheating an object to be soldered, a solder bath having a jet nozzle for soldering the object to be soldered preheated by the preheater, and a solder bath having the same. 9. The cooling device for the soldering object according to claim 3, wherein the cooling device cools the soldering object immediately after being soldered by the preheater, the jet nozzle of the solder bath, and the cooling device for the soldering object. And an inert atmosphere chamber for forming an inert atmosphere inside the soldering apparatus.

Then, a mist, which is a finely atomized liquid, is supplied to the object to be soldered immediately after being soldered by the jet nozzle of the solder tank in the inert atmosphere chamber, and the high-temperature soldering is performed by soldering. Provided is a jet-type soldering apparatus capable of rapidly cooling an object to be soldered without significantly affecting the residual oxygen concentration in an inert atmosphere chamber by removing latent heat of vaporization from the object and suppressing a fillet lift-off phenomenon. .

According to a tenth aspect of the present invention, there is provided a preheat furnace for preheating a material to be soldered, a reflow furnace continuously provided in the preheat furnace for reflow heating the material to be soldered, and a reflow furnace. 9. The cooling device for the soldering object according to claim 3, wherein the cooling device cools the soldering object immediately after the reflow soldering, and covers the preheating furnace, the reflow furnace, and the cooling device for the soldering object. And an inert atmosphere chamber for forming an inert atmosphere therein.

Then, a mist, which is a finely atomized liquid, is supplied to the object to be soldered immediately after reflow soldering in a reflow furnace in an inert atmosphere chamber, and the high-temperature object to be soldered is supplied by soldering. By removing the latent heat of vaporization, the object to be soldered is rapidly cooled without significantly affecting the residual oxygen concentration in the inert atmosphere chamber,
Provided is a reflow soldering apparatus capable of suppressing a fillet lift-off phenomenon.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS.

FIG. 1 and FIG. 2 show an embodiment of a cooling device 11 for a soldering object. The cooling device 11 for a soldering object is an ultra mist supply device for finely atomizing a liquid by ultrasonic waves. It is formed around the sonic atomizer 12.

The ultrasonic atomizer 12 is provided with a bottom 13 of a liquid tank 13.
a, and an ultrasonic vibrator 15 is provided between the bottom plate 14 separately disposed below the liquid tank 13, and a radiator 17 is provided below the bottom plate 14 via a thermo module 16. I have.

The thermo module 16 disposed below the liquid tank 13 keeps the temperature of the liquid in the liquid tank 13 at a fixed set temperature, and generates heat by a temperature increase signal from a temperature control device (not shown). Then, heat is applied to the liquid 18 in the liquid tank 13 via the bottom plate 14 and the ultrasonic vibrator 15, and the liquid 18 in the liquid tank 13 absorbs heat by a temperature lowering signal, and the ultrasonic vibrator 15 and the bottom plate The heat is deprived via 14 and the heat is radiated from the radiator 17.

As shown in FIG. 2, the mounting structure of the ultrasonic vibrator 15 has a hole 13b opened at the bottom 13a of the liquid tank 13.
A packing receiving portion 13c is provided in an arc shape around the periphery of the container, and an O-ring-shaped packing 19 is fitted below the packing receiving portion 13c.
Liquid tightness between 13a and the ultrasonic transducer 15 fixed to the bottom plate 14 is maintained.

The mounting structure of the ultrasonic vibrator 15 is
And the ultrasonic transducer 15 can be easily separated,
The cleaning of the liquid tank 13 is facilitated, and the management and maintenance of the ultrasonic vibrator 15 are facilitated.

As shown in FIG. 1, a liquid supply device 21 is connected to the liquid tank 13. This liquid supply device 21 is provided with a water pipe 22
A water storage tank 23 is connected to the water storage tank 23.
A deionized water generator 25 having a built-in ion exchange resin membrane is connected, and a deionized water supply pipe 26 drawn from the deionized water generator 25 is connected to the liquid tank 13. An electromagnetic valve 27 for controlling the liquid level is interposed in the deionized water supply pipe.

The water storage tank 23 is provided with a float valve (not shown) for controlling the amount of water supplied from the water supply pipe 22 to keep the water level in the water storage tank 23 constant. Also,
The water storage tank 23 is provided at a position higher than the liquid tank 13 or incorporates a pump to supply deionized water to the liquid tank 13 via the deionized water generator 25.

The solenoid valve 27 of the deionized water supply pipe 26
On / off control is performed by a signal from a floatless switch 28 such as a liquid level detection rod installed at a predetermined level in the liquid tank 13, the liquid level is closed by detecting the liquid level of the floatless switch 28, and opened by detecting no liquid level. Thus, the liquid level in the liquid tank 13 is controlled within a range of a predetermined level.

Further, an upper part of the liquid tank 13 is provided with an expanding part 13d having a shape which is expanded upward, and a gas is provided on the inner peripheral surface of the liquid tank 13 below the expanding part 13d. The barrier forming pipe 31 is disposed endlessly.

A large number of gas ejection holes 32 are formed at a constant pitch in the upper surface of the gas barrier forming pipe 31 over the entire length. An inert gas supply source 34 for supplying an inert gas such as nitrogen gas is connected to the gas barrier forming pipe 31 through a pipe 33. The inert gas supply source 34 is, for example, a nitrogen gas tank or a nitrogen gas generator. Note that a blower (not shown) with an air filter may be connected to the pipe line 33 instead of the inert gas supply source.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be described.

The electromagnetic valve 27 is controlled by the floatless switch 28 so that the liquid 18 in the liquid tank 13 has the set liquid level. The liquid 18 supplied to the liquid tank 13 is formed by converting tap water into deionized water using an ion exchange resin membrane of a deionized water generator 25, and the deionized water can be easily generated using the ion exchange resin membrane.

The ultrasonic vibrator 15 of the ultrasonic atomizing device 12 has 40
When power having a frequency of 0 KHz to 1 MHz is supplied, the surface tension of the liquid surface is broken by ultrasonic vibration, and a large amount of low-temperature mist M finely atomized from the low-temperature liquid surface is generated one after another. The deionized water is a water having a stable property from which ions have been removed, and thus has a small and uniform particle diameter when finely atomized.

The thermo module 16 disposed below the liquid tank 13 keeps the liquid temperature in the liquid tank 13 at a set temperature.
Even if the external temperature condition changes, it helps to create the finely atomized mist M always under the optimum temperature condition.

Then, an inert gas or air is supplied to the gas barrier forming pipe 31 from an inert gas supply source 34 set at a low pressure or an ultra-small blower (not shown), and the gas barrier forming pipe 31 is supplied. When a weak inert gas flow or a weak air flow is ejected from the gas ejection holes 32 of these, the weak inert gas flow or the air flow forms the gas barrier 35 over the entire circumference of the liquid tank 13, so that the mist M rises to a substrate transfer level 36 within a limited area so as to be confined in the gas barrier 35, and is always flat and compact along the substrate transfer level 36, and a mist cooling area (mist barrier) is formed. ) Is formed.

The board transfer level 36 is provided with board transfer conveyors 42 and 54 (FIGS. 4 and 5) as holding means for holding an object to be soldered.

The printed circuit board P as an object to be soldered immediately after soldering is heated to a high temperature, but when passing through the mist barrier, the low-temperature mist finely atomized on the printed circuit board P is When M comes into direct contact, the mist M is vaporized by conduction heat from the high-temperature printed circuit board P, and at that time, the mist M functions as a refrigerant for removing latent heat of vaporization (phase conversion heat) from the amount of heat retained in the printed circuit board P. Therefore, the printed circuit board P is rapidly cooled to suppress the fillet lift-off phenomenon that occurs during slow cooling.

At this time, the molten solder of the printed circuit board P comes into contact with the mist M during solidification. However, the fine mist M of 10 to 100 μm has no effect on the solidification process of the solder. Only the solidification rate is increased.

FIG. 3 shows actually measured values of the cooling characteristics of the cooling device 11 for the object to be soldered.
, The cooling characteristic of the cooling fan in the atmosphere is indicated by b, and the cooling characteristic of the mist M generated from the device is c.
To c ′.

According to this characteristic diagram, when the output to the ultrasonic vibrator 15 is weakened and the amount of mist generation is controlled to be small (c), the cooling characteristic a due to natural standing and the cooling characteristic b due to the cooling fan are different. However, when the output to the ultrasonic vibrator 15 is increased and the amount of mist generation is controlled in a large amount (c '), it can be understood that the cooling can be performed more efficiently than the cooling characteristic b by the cooling fan.

FIG. 4 shows a jet-type soldering apparatus incorporating the cooling device 11 for the object to be soldered shown in FIGS. 1 and 2, and a board for transporting the printed board P inside the outer cover 41. A transport conveyor 42 is disposed in an inclined manner, and a spray fluxer 44 for spraying a flux onto the printed circuit board P along a transport path 43 of the printed circuit board P transported by the board transport conveyor 42; A preheater 45 for preheating; a solder tank 46 provided with a primary jet nozzle 46a and a secondary jet nozzle 46b for soldering the mounted components to the lower surface of the printed circuit board P; A cooling device 11 for rapidly cooling the printed circuit board P is arranged in order.

The preheater 45 and the solder bath 46
The secondary jet nozzle 46a and the secondary jet nozzle 46b, and the cooling device 11 for an object to be soldered are connected to an inert atmosphere chamber 47.
Covered by

The inert atmosphere chamber 47 has an inert gas supply port 48 for receiving an inert gas such as nitrogen gas, and an inert atmosphere such as nitrogen gas is formed inside the chamber so that the residual gas in the chamber remains. The oxygen concentration is controlled to a certain value or less.

The inert atmosphere chamber 47 is provided with an entrance 47a for carrying the printed circuit board P and a printed circuit board P.
An outlet 47b for discharging the solder and a nozzle insertion hole 47c for being inserted into the molten solder in the solder bath 46 are respectively opened. A mounting opening 47e is opened at the lower part of the portion 47d, and the ultrasonic atomizing device 12 of the cooling device 11 for the soldering object shown in FIGS. Installed.

The concentration of the residual oxygen in the inert atmosphere chamber 47 is kept low by an inert gas atmosphere such as nitrogen gas supplied from the inert gas supply port 48 into the inert atmosphere chamber 47. The concentration is an oxygen concentration meter 49
To control the flow rate control valve provided in the inert gas supply pipe to maintain the concentration at the set level.

In this jet type soldering apparatus, immediately after the soldering of the printed circuit board P is completed by the jet solder from the primary jet nozzles 46a and the secondary jet nozzles 46b in the inert atmosphere chamber 47, the inert gas is removed. Ultrasonic atomizer 12 of cooling device 11 for soldering object in atmosphere chamber 47
Is supplied to the printed circuit board P and is vaporized by the conduction heat from the printed circuit board P. At this time, the mist removes latent heat of vaporization from the printed circuit board P, thereby rapidly cooling the printed circuit board P.

At this time, since the mist only changes phase from the liquid phase to the gas phase and does not cause pressure fluctuation in the atmosphere in the inert atmosphere chamber 47 unlike a conventional cooling fan, the mist Is not significantly affected by the cooling device 11 for the object to be soldered.

FIG. 5 shows a reflow soldering apparatus in which the cooling apparatus 11 for the object to be soldered shown in FIGS. 1 and 2 is incorporated.

The printed circuit board P is provided inside the inert atmosphere chamber 51 from the substrate carrying port 52 opened at one end to the substrate carrying port 53 opened at the other end.
Is provided, and a plurality of preheat furnaces 55a and 55b are provided along the substrate transfer conveyor 54.
, 55c are provided integrally, and a plurality of reflow furnaces 57a, 57b are provided integrally via a duct portion 56. Further, in the vicinity of the outlet 58 of the last reflow furnace 57b and below the substrate transport conveyor 54, A pair of soldering object cooling devices 11 for rapidly cooling at least one of the lower surface and the upper surface of the high-temperature printed circuit board P immediately after soldering,
11a are installed facing each other.

As the cooling device 11 for the object to be soldered disposed below the substrate transport conveyor 54, the one shown in FIGS. 1 and 2 is used as it is, but the device for cooling the soldering object disposed above the substrate transport conveyor 54 is used. The accessory cooling device 11a includes a liquid tank 13 and a gas barrier forming pipe 31 in the ultrasonic atomizer 12 shown in FIGS.
A means for causing the mist to overflow from the upper opening of the substrate and for attracting the overflowed mist to a lower substrate transfer level, for example, a guide duct is provided.

In each of the preheat furnaces 55a, 55b, 55c and in each of the reflow furnaces 57a, 57b, there are provided a heater 61 capable of controlling the amount of heat generated by the amount of electricity supplied, and a sirocco fan 62 for forcibly circulating the atmosphere in the furnace. Is provided.

At the bottom of each of the preheating furnaces 55a, 55b, 55c and each of the reflow furnaces 57a, 57b, nozzles 63 for blowing an inert gas such as nitrogen gas into the furnace are provided. The active gas supply pipes 64 are respectively connected, and adjustment valves 65 for adjusting the flow rate of the inert gas supply are provided in the respective inert gas supply pipes 64.

In the inert atmosphere chamber 51, the inlet 66 of the first preheat furnace 55a supplied from the nozzle 63
Or the nitrogen gas flowing out of the outlet 58 of the last reflow furnace 57b, or the nitrogen gas directly supplied into the inert atmosphere chamber 51 through a pipe (not shown).
An inert atmosphere in which the concentration of residual oxygen is low and controlled is formed.

Then, each of the preheat furnaces 55a, 55b, 55c
Then, the inert gas such as nitrogen gas supplied into the furnace from the nozzle 63 is heated by the heater 61 when circulated by the sirocco fan 62, and becomes a relatively low-temperature hot air lower than the solder reflow temperature, so that the substrate transfer conveyor is heated. The component-mounted printed circuit board P conveyed by 54 is preheated.

Further, in each of the reflow furnaces 57a and 57b, an inert gas such as nitrogen gas supplied from the nozzle 63 into the furnace is heated by the heater 61 when circulated by the sirocco fan 62, and the temperature of the inert gas is lower than the solder reflow temperature. It becomes high temperature hot air,
The printed circuit board P on which components are transported by the substrate transport conveyor 54 is reflow-heated to dissolve the solder paste.

In this reflow soldering apparatus, immediately after the reflow soldering of the printed circuit board P is completed by reflow heating, the mist is cooled by the printed circuit board P in the inert atmosphere chamber 51 from the cooling device 11, 11a of the object to be soldered.
The mist is vaporized by conduction heat from the printed circuit board P heated to a high temperature, and the mist removes latent heat of vaporization from the printed circuit board P at this time, thereby rapidly cooling the printed circuit board P.

At this time, since the mist only changes phase from the liquid phase to the gas phase and does not cause a pressure fluctuation in the inert atmosphere in the inert atmosphere chamber like a cooling fan, the mist remains in the inert atmosphere chamber. The oxygen concentration is not significantly affected by the cooling devices 11 and 11a.

Also, a pair of upper and lower cooling devices for the object to be soldered is provided.
11, 11a can selectively supply mist atomized finely to the lower surface, upper surface or both surfaces of the printed circuit board P as needed. For example, if mist is supplied to both surfaces of the printed circuit board P at the same time, The cooling efficiency can be further improved than in the case.

As described above, in the jet type soldering apparatus, immediately after the soldering of the printed circuit board P by the jet solder is completed, and in the reflow type soldering apparatus, the printed circuit board P is soldered by reflow heating. Immediately after completing the above, both of the inert atmosphere chambers 47, 51
By supplying the mist to the printed circuit board P in the inside and removing the latent heat of vaporization from the printed circuit board P, the printed circuit board P can be rapidly cooled without affecting the low oxygen concentration atmosphere in the inert atmosphere chambers 47 and 51. .

That is, the miniaturized refrigerant is brought into direct contact with the printed circuit board P in the inert atmosphere chambers 47 and 51 to be vaporized by conduction heat.
By removing the latent heat of vaporization (phase conversion heat) from the retained heat, the printed circuit board P can be rapidly cooled without changing the residual oxygen concentration in the inert atmosphere chamber.

The mist supply device is an ultrasonic atomizing device.
A spray nozzle for spraying the finely atomized mist M as well as 12 may be used. Further, as the liquid 18 in the liquid tank 13, an inert liquid may be used instead of deionized water.

[0073]

According to the first aspect of the present invention, the fine mist is supplied to the object to be soldered immediately after soldering, so that the mist in contact with the object to be soldered has a high temperature. Since the latent heat of vaporization is removed from the object, the object to be soldered is rapidly cooled, and the fillet lift-off phenomenon can be suppressed.

According to the second aspect of the present invention, the fine mist which is selectively supplied to at least one of the lower surface and the upper surface of the printed circuit board as the object to be soldered is supplied. The lower surface, the upper surface or both surfaces can be rapidly cooled by mist as required.

According to the third aspect of the present invention, when the mist supplied from the mist supply device comes into contact with the soldered object to be soldered, the mist deprives the high temperature object of the evaporation of latent heat of vaporization. The material to be soldered is rapidly cooled, and the fillet lift-off phenomenon can be suppressed.

According to the fourth aspect of the present invention, the liquid in the liquid tank can be finely atomized at a low temperature by the ultrasonic vibrator, and a fine and low-temperature mist suitable for rapid cooling of the material to be soldered can be produced.

According to the fifth aspect of the present invention, since deionized water can be easily produced and is a water having a stable property from which ions have been removed, the particle size when atomized finely can be made small and uniform. .

According to the sixth aspect of the present invention, since the ultrasonic vibrator is provided in a liquid-tight manner through the packing below the hole opened in the bottom of the liquid tank, the ultrasonic vibrator is connected to the liquid tank through the packing. The ultrasonic transducer can be separated from the ultrasonic transducer, so that the liquid tank can be easily cleaned, and the ultrasonic transducer can be easily managed and maintained.

According to the seventh aspect of the present invention, the liquid temperature in the liquid tank is maintained at the set temperature by the thermo module, so that the fine atomization is always performed under the optimum temperature condition even when the external temperature condition changes. Mist can be made.

According to the eighth aspect of the present invention, the gas barrier is formed over the entire circumference of the liquid tank by the gas barrier forming pipe disposed on the inner peripheral surface of the liquid tank. However, it is kept in a limited area so as to be confined in the gas barrier, and a cooling area by a compact mist can be formed.

According to the ninth aspect of the present invention, the mist which is a finely atomized liquid is supplied to the object to be soldered immediately after being soldered by the jet nozzle of the solder tank in the inert atmosphere chamber, A jet that removes the latent heat of vaporization from a high-temperature soldering object during soldering, rapidly cools the soldering object without significantly affecting the residual oxygen concentration in the inert atmosphere chamber, and suppresses the fillet lift-off phenomenon A soldering device of the type can be provided.

According to the tenth aspect of the present invention, the mist, which is a finely atomized liquid, is supplied to the object to be soldered immediately after the reflow soldering in the reflow furnace in the inert atmosphere chamber to perform the soldering. Reflow type that removes the latent heat of vaporization from the high-temperature soldering object and rapidly cools the soldering object without significantly affecting the residual oxygen concentration in the inert atmosphere chamber, thereby suppressing the fillet lift-off phenomenon Can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an apparatus for cooling an object to be soldered according to the present invention.

FIG. 2 is a sectional view of the cooling device.

FIG. 3 is a characteristic diagram showing a cooling characteristic of the cooling device.

FIG. 4 is a cross-sectional view showing a jet-type soldering device incorporating the cooling device.

FIG. 5 is a cross-sectional view showing a reflow soldering device incorporating the cooling device.

FIG. 6 is a cross-sectional view of a printed circuit board showing a fillet lift-off phenomenon caused by conventional slow cooling.

[Explanation of symbols]

 P Printed circuit board as the object to be soldered M Mist 11, 11a Cooling device for the object to be soldered 12 Ultrasonic atomizer as mist supply device 13 Liquid tank 13b Hole 15 Ultrasonic vibrator 16 Thermo module 18 Liquid (deionized water ) 19 Packing 31 Gas barrier forming pipe 35 Gas barrier 42, 54 Substrate transfer conveyor as holding means 45 Preheater 46 Solder bath 46a, 46b Jet nozzle 47 Inert atmosphere chamber 51 Inert atmosphere chamber 55a, 55b, 55c Preheat furnace 57a , 57b reflow furnace

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B23K 31/02 310 B23K 31/02 310H // B23K 101: 40 (72) Inventor Teruo Okano Sayama, Saitama 591-11, Kamihirose Oaza, in the Tamura FE System Co., Ltd. (72) Inventor Hidekazu Imai 591-11, Kamihirose, Oaza, Sayama City, Saitama Prefecture Address 11 F-term in the Tamura FA system (reference) 4E080 AA01 AB03 AB05 AB06 BA07 CB04 5E319 AC01 CC24 CC33

Claims (10)

[Claims] 1. A method for cooling an object to be soldered, comprising supplying finely atomized mist to the object to be soldered immediately after soldering to cool the object to be soldered. 2. An object to be soldered is a printed circuit board,
2. The method according to claim 1, wherein a finely atomized mist is selectively supplied to at least one of a lower surface and an upper surface of the printed circuit board. 3. An object to be soldered, comprising: holding means for holding an object to be soldered; and a mist supply device for supplying finely atomized mist to the object to be soldered. Cooling system. 4. The soldering apparatus according to claim 3, wherein the mist supply device includes a liquid tank containing the liquid, and an ultrasonic vibrator for finely atomizing the liquid in the liquid tank. Object cooling device. 5. The apparatus for cooling an object to be soldered according to claim 4, wherein the liquid is deionized water. 6. The liquid tank has a hole opened at the bottom, and the ultrasonic vibrator is provided below the hole in a liquid-tight manner through a packing fitted to the periphery of the hole. 6. The cooling device for an object to be soldered according to claim 4, wherein: 7. The cooling device for a soldered object according to claim 4, further comprising a thermo module for maintaining a liquid temperature in the liquid tank at a set temperature. 8. The gas barrier forming pipe according to claim 4, further comprising a gas barrier forming pipe disposed on an inner peripheral surface of the liquid tank and forming a gas barrier over the entire circumference of the liquid tank. Cooling equipment for soldering objects. 9. A preheater for preheating an object to be soldered, a solder bath having a jet nozzle for soldering the object to be soldered preheated by the preheater, and a solder bath immediately after being soldered in the solder bath. 9. An apparatus for cooling an object to be soldered according to claim 3, which cools an object to be soldered, and an inert atmosphere inside which covers the preheater, the jet nozzle of the solder bath and the apparatus for cooling an object to be soldered. And an inert atmosphere chamber for forming the solder. 10. A preheat furnace for preheating a material to be soldered, a reflow furnace continuously provided in the preheat furnace for reflow heating the material to be soldered, 9. An apparatus for cooling an object to be soldered according to any one of claims 3 to 8, which cools an object to be soldered, and forms an inert atmosphere therein by covering the preheat furnace, the reflow furnace, and the apparatus for cooling an object to be soldered. And an inert atmosphere chamber.