JPH10296435A - Soldering method - Google Patents

Abstract

(57) [Summary] [Problem] Without giving a thermal shock to the surroundings within a short time,
A more reliable solder joint is collectively formed between a plurality of base materials arranged three-dimensionally. A squeegee (12) is used to fill a solder paste discharged from a dispenser (11) into a groove (8b) formed on a heating surface (8a) of a heating tool (8). Thereafter, the heating tool 8 is advanced, and the tips of the respective lead rows of the package 1 stacked on the jig 2A are slightly inserted into the respective grooves 8b. Then, heating tool 8
To heat and melt the solder paste. After the main heating of the solder paste, the heating of the heating tool 8 is stopped,
The leading end of the lead row of the package 1 stacked on the jig 2A is left inserted into the groove 8b. When the molten solder is completely solidified, the heating tool 8 is retracted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering technique, and more particularly to a soldering method suitable for collectively forming a solder joint for connecting a plurality of three-dimensionally arranged electronic components.

[0002]

2. Description of the Related Art Soldering techniques, which are regarded as indispensable joining techniques in the electronics industry, have been successively improved in accordance with changes in the mounting method of electronic equipment. At present, when the mounting method of electronic components on a board has changed from the insertion method to the surface mounting method, a new soldering method corresponding to the method has already been developed. The solder printing method and the precoat method described below are typical examples.

[0003] One solder printing method uses one base material.
(For example, screen printing of a solder paste on a component mounting pattern on a substrate), and mounting the other base material (for example, a pad of an electronic component) thereon, and then applying the solder paste to an appropriate heating method ( 2) by heating and melting
This is a soldering method for forming a solder joint between two base materials.
The solder paste referred to here is an active flux and fine solder powder (Sn-Pb alloy solder, Sn-Ag alloy solder)
And a kneaded creamy solder material.

[0004] In the other precoat method, a solder bump is formed on one base material which has been previously coated with solder plating, a flux is supplied, and then the other base material is placed thereon. This is a soldering method in which a solder joint is formed between two base materials by heating and melting the solder bump by an appropriate heating method (described later). Since the precoat method is effective in preventing the occurrence of a bridge which is one of the soldering defects, it is often used when the mounting density of electronic components on a substrate is high.

[0005] These two soldering methods are generally used together with one of the two types of heating methods described below. One heating method is
This is a batch reflow method in which electronic components and the like are entirely heated inside a reflow furnace or the like, and the other heating method is a local heating method in which only the vicinity of a base material is locally heated by contact with a heating tool. The batch reflow method has the advantage of being excellent in mass productivity and not restricting the soldering location, but has the disadvantage that the adverse effects of heat are likely to affect electronic components and other components. While there is a disadvantage that the mass production is inferior and the soldering part is restricted by interference between the heating tool and the electronic component, there is an advantage that the adverse effect of heat is less likely to affect the electronic component and other components. Therefore, taking into account the heat resistance of electronic components and other components, the layout of electronic components on the substrate, and other conditions, the magnitude of the effect of the disadvantages and advantages of these two heating methods is compared and examined. Is usually selected.

[0006]

By the way, in conjunction with the miniaturization and high-density of electronic equipment, a new mounting method capable of effectively utilizing the space above the substrate, specifically,
A three-dimensional mounting method for stacking a plurality of electronic components on a substrate has been proposed. Therefore, it is necessary to develop a new soldering method corresponding to such a new mounting method. The above two soldering methods developed corresponding to the surface mounting method are not suitable for soldering between base materials arranged in a vertical direction. This is because, even if a method of soldering between a plurality of electronic components is adopted, occurrence of a trouble is inevitable. For example, when the solder printing method is adopted, in most cases, solder paste is evenly spread on the leads of all the electronic components due to interference between a screen and a jig for holding a plurality of electronic components at the time of soldering. Cannot be screen printed. Even if the solder paste can be screen-printed evenly on the leads of all the electronic components, the solder paste whose flux viscosity has decreased may fall off the leads during heating.
On the other hand, when the pre-coating method is employed, there is an industrial limit to the amount of solder supplied per lead, and therefore, in most cases, the thickness (typically 50 μm Above) cannot be formed. In some cases, a wicking phenomenon and other poor soldering may occur.

For these reasons, there is a demand for the development of a new soldering method corresponding to a three-dimensional mounting method. However, under the current situation where there is an increasing demand for a reduction in manufacturing cost, such a new soldering method is required. Needless to say, when developing the soldering method, it is required to improve both the efficiency and the yield of the soldering process.

Therefore, the present invention provides a solder joint having a higher reliability in a short time between a plurality of base materials arranged three-dimensionally without giving a thermal shock to other surrounding components. It is an object of the present invention to provide a soldering method capable of forming a single package.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method in which a molten filler material flows between base materials to be joined to each other among a plurality of base materials arranged three-dimensionally. A joining method for selectively joining the plurality of base materials, wherein the plurality of base materials are provided on a heating surface of a heating tool maintained at a temperature lower than a melting point of the filler material. A first step of adhering a filler material having a shape that comes into contact only with the base material to be joined to each other, and the heating tool so that the plurality of base materials contact the filler material on the heating surface of the heating tool. And a second step of bringing the plurality of base materials closer to each other, a third step of starting heating the heating tool so that the filler material on the heating surface of the heating tool is melted, and a predetermined heating time. After the elapse, the surface temperature on the heating surface of the heating tool is A fourth step of starting to cool the heating tool so that the temperature is equal to or less than a point, and after a predetermined cooling time has elapsed, the filler material solidified during the cooling time is peeled off from the heating surface of the heating tool. And a fifth step of keeping the heating tool and the plurality of base materials away from each other.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, a lamination mounting process of a resin mold package, which is widely used for a portable information terminal or the like, will be described as an example.

First, a resin mold package to be soldered in the present embodiment will be described.

This resin mold package (hereinafter referred to as a package) is a thin flat-pack type package developed in response to demands for downsizing, thinning, and lightening of electronic devices. On both sides of this package body, an appropriate lead width (typically 0.15 mm to
0.3mm) lead is suitable pitch (usually 0.4m
m to about 0.65 mm). The leads of this package are all bent at a predetermined angle with their tips directed downward (see FIG. 4B). Therefore, a plate of Cu, 42Fe-Ni, or another conductive material excellent in formability, particularly a plate having a plate thickness of about 35 to 125 µm, is usually used for the lead. However, in order to reliably solder between the leads of the upper package and the leads of the lower package in a state where the packages are stacked, the displacement of the tips of the leads of the respective packages in the vertical direction is as follows. It is desirable that the thickness be suppressed to at least about 50 μm. For the same reason, it is preferable that the lead pitch error is suppressed to at least 1/4 or less of the lead width.

Next, a resistance heating type heating tool used in the present embodiment will be described with reference to FIG.

The tip 8a of the heating tool 8 (hereinafter referred to as a heating surface) has the same pitch as the lead of the package.
A groove 8b is formed for filling with a solder paste. The length t of these grooves 8b is determined according to the number of packages stacked and mounted on the substrate. The width d of these grooves 8b is set slightly larger than the width D of the package leads in consideration of the positioning accuracy of the lead group to be joined to each other. The depth s of these grooves 8b is set according to the volume of the solder paste required to form a solder joint having a target thickness.
For example, as the target thickness of the solder joint becomes thicker, more solder paste is required. Therefore, it is necessary to make each groove 8b deeper. Conversely, as the target thickness of the solder joint becomes thinner, it is necessary to make each groove 8b shallower accordingly.

The heating tool 8 is made of a conductive material (tungsten, Kovar, molybdenum steel, etc.) that is hardly wet by the molten solder and hardly corroded by the flux contained in the solder paste. The heating tool 8 is formed with two power supply legs 8c for attaching an external electrode (not shown) for supplying the pulse current A.

The holes 8d formed in the two power supply legs 8c are holes for passing bolts for fixing the main heating tool 8 to the soldering device side.

Next, a soldering method using the heating tool will be described.

First, it is necessary to set the package 1 in a solderable state. Specifically, FIG.
As shown in (a), the positioning pin holes 1a of the package 1 are sequentially inserted into the two positioning pins 4 erected on the jig 2A, and a predetermined number of packages 1 are attached to the jig 2A. After stacking on top, press jig 2 from above
B, and as shown in FIG.
The package 1 may be sandwiched between the package 1 and the jig 2A. As a result, all the leads 3 of the upper package 1
As shown in FIG. 4B, positioning is performed with appropriate positioning accuracy with respect to the leads 3 of the package 1 in the lowermost layer. Specifically, the positional deviation of the leads 3 of the upper package 1 in the X direction with respect to the leads 3 of the lowermost package 1 is suppressed to at most ± ()) · D (D: lead width). be able to. The package group set in such a state is hereinafter referred to as a package laminate.

By the way, the jig 2 with the positioning pins 4
When A is used, it is necessary to provide a positioning pin hole 1a also on the package 1 side, but without using a jig 2A having positioning pins 4 as shown in FIG. When such a positioning device is used, it is not necessary to provide the positioning pin hole 1a on the package 1 side. This positioning device includes four movable tables 500a that press the jig 2A from both sides. These four moving tables 5
When the jig 2A is pressed down at 00a, the positioning members 500c standing on the four movable tables 500a are brought into contact with both the side surfaces of the package 1 stacked on the jig 2A and the outermost leads. It is designed to be placed in various positions. Therefore, first, these four moving tables 50
If the package 1 is dropped on the jig 2A while keeping the outermost leads along all four positioning members 500c, the jig 2A with the positioning pins 4 is pressed. In the same manner as in the case where is used, the leads 3 of the upper package 1 can be positioned with appropriate positioning accuracy with respect to the leads 3 of the lowermost package 1.
Then, after the holding jig 2B is further mounted thereon, these may be integrally removed from the positioning device. Here, the mating surface of the pressing jig 2B to be used, are fitted with axial for fitting into the hole A ₁ of the jig 2A.

After the above setting is completed, the lead rows of the package stack are soldered according to the processing procedure shown in FIG. First, in S200, the finned block material 14 that has been cooled in advance is pressed against a surface other than the heating surface 8a of the heating tool 8, as shown in FIG. The finned block material 14 used here is
It is formed by molding a material having a higher thermal conductivity than the heating tool 8 (for example, aluminum). Then, the heating tool 8 is cooled down until the temperature of the heating surface 8a of the heating tool 8 becomes equal to or lower than the melting point of the solder.

In the present embodiment, only the finned block member 14 is used to cool the heating tool 8, but a fan for blowing air is used in combination so as to improve the cooling efficiency of the heating tool 8. No problem. Further, instead of the finned block member 14, for example, a water-cooled jacket or other cooling device may be used.

Next, in S201, as shown in FIG. 5B, the dispenser 11 is moved in the X direction along the heating surface 8a of the heating tool 8 while continuously discharging an appropriate amount of solder paste from the dispenser 11. . The solder paste used here contains a flux of a type suitable for the material of the lead and the like. For example, 4
When the lead is formed of 2Fe-Ni or another material having poor wettability, or when the lead is not coated with Sn plating, Ag plating, or other solder plating, a solder containing a highly active flux is used. It is necessary to use a paste, but if the lead is made of Cu or other material having good wettability, or if the lead is covered with Sn plating, Ag plating or other solder plating, cleaning is not required A solder paste containing a suitable resin flux and a weakly active flux can be used.

Thus, the heating surface 8 of the heating tool 8
5A, a linear solder paste extending from the first groove to the last groove is applied on the heating tool 8a, and then a spatula squeegee 12 is placed on the heating surface 8a of the heating tool 8 as shown in FIG. To fill the inside of the groove 8b formed on the heating surface 8a of the heating tool 8 with the solder paste, and to prevent the bridge or other sagging that causes soldering failure from occurring, except for the groove 8b. All the excess solder paste adhering to the region is removed.

Thereafter, in S202, as shown in FIG. 5D, the package laminate is arranged in front of the heating surface 8a of the heating tool 8. At this time, it is necessary to accurately align the lead rows of the package stack with the grooves formed on the heating surface 8a of the heating tool 8. Then, after the finned block member 14 is retracted, the heating tool 8 is advanced to a predetermined position, thereby forming a groove 8b formed on the heating surface 8a of the heating tool 8 as shown in FIG. , The tip of the lead row of the package laminate is slightly inserted. Here, “slightly insert” means “the end of the lead row of the package laminate is
b so as to be in contact with the solder paste 7 filled in the inside of b. " As a result, FIG.
As shown in (a), the lead rows to be joined to each other, that is, the tips of the leads 3 arranged in the vertical direction are accommodated in one groove.

Thereafter, the heat treatment of the solder paste is started according to the soldering schedule shown in FIG. Specifically, in S203, first, a pulse current A is supplied to the heating tool 8 from an external electrode (not shown) to remove the solder paste 7 filled in the groove 8b of the heating surface 8a of the heating tool 8. Preheat. Preheating temperature T _{1 at} this time
The surface temperature of the heating surface 8a of the heating tool 8 is about 1
It is said that a temperature of about 50 ° C. is desirable. The main purpose of this preheating is to activate an activator (such as chlorine) in the flux contained in the solder paste 7 and to dry a solvent in the flux.

[0026] After this state was maintained preheating temperature T ₁ of the predetermined preheating time t ₁ has elapsed, in the subsequent S204, the solder melt the solder paste is filled in the trench 8b of the heating surface 8a of the heating tool 8 The main heating is performed to the temperature T ₀ or more. The main heating temperature T _{2 at} this time is Sn63P
b (melting point: 183 ° C.), the temperature of the heating surface 8a of the heating tool 8 is about 240 ° C., and Sn95Ag or other high melting point solder is used.
When a solder paste containing (having a melting point of 245 ° C. or higher) is used, it is desirable that the surface temperature of the heating surface 8a of the heating tool 8 be about 320 ° C. In the present embodiment, since local heating is used, in which the heating efficiency of the solder paste is high and the influence of heat on the surroundings is small, almost no thermal shock is applied to the package 1 regardless of which solder paste is used. , The solder paste 7 can be sufficiently heated and melted in a short time. And
Lead columns to be joined together, i.e., as spreads molten solder to the lead 3 groups arranged in the vertical direction, left to stand to maintain this state the heating temperature T _2.

When the predetermined main heating time t ₂ has elapsed, in step S205, the supply of the pulse current from the external electrode is stopped, and the heating of the heating tool 8 is terminated. Then, in the subsequent S206, without retracting the heated tool 8, if left for a predetermined cooling time t ₃ in this state. Thereby, the heating surface 8a of the heating tool 8
Surface temperature below the solder melting temperature T ₀ of begins to gradually solidify the molten solder is filled between the upper and lower leads of the lead column to be joined together. Since the heating tool 8 is not set back until the molten solder filled between the upper and lower leads of the lead row to be joined to each other is completely solidified, the heating surface 8a of the heating tool 8 is The interfacial tension acting between the molten solder and the molten solder can prevent the molten solder filled between the upper and lower leads of the lead row to be joined from falling off. Therefore, eventually, each lead row of the package stack can be completely joined. Note that the required time (t ₁ + t ₂ + t ₃ ) from the start of the preheating in S203 is about 1 / l of the heating time of the batch reflow method described in the section of the prior art.
It is enough to allow about 6 hours (at most about 10 seconds).

Then, in S208, the heating tool 8
Is retreated, the solder joint is peeled off from the heating surface 8a of the heating tool 8, and both the jig 2A and the holding jig 2B are removed from the completed package laminate.

Then, in the case where the lead group of the new package laminate is to be soldered continuously, immediately in step S 209, other than the heating surface 8 a of the heating tool 8, so as to reduce unnecessary waiting time. Is pressed against the finned block material 14 which has been cooled in advance. If the flux residue remains on the heating surface 8a of the heating tool 8, before cooling the heating tool 8 with the finned block material 14, the heating tool 8 is washed with a cleaning liquid suitable for the polarity of the flux residue. By heating the heating tool 8 to about 50 to 80 ° C. while immersing the heating surface 8a, the flux residue remaining on the heating surface 8a of the heating tool 8 is removed, and then further heated and dried in the air. You need to keep it.

As described above, according to the soldering method according to the present embodiment, the plurality of solder joints for joining the lead rows of the package laminate can be formed within a short time without giving a thermal shock to the surroundings. They can be formed at once. In addition, by filling the inside of the groove formed on the heating surface of the heating tool with the solder paste, the effect of preventing the solder paste from dripping during preheating or the like is obtained, so that a bridge or other soldering defect is prevented. Can be greatly reduced. In addition, the molten solder can be sufficiently filled between the upper and lower leads to be joined to each other, and the molten solder can be completely solidified while maintaining the state. Can be reliably formed. Further, thermal deformation of the lead is prevented by the inner wall of the groove formed on the heating surface of the heating tool, so that a situation in which the laterally arranged leads are extremely close to each other occurs, that is, the leads should not be originally bonded. It is possible to prevent a situation in which the leads are joined to each other beforehand.

By the way, even if a heating tool other than such a heating tool having a groove, for example, a heating tool in which a groove for filling the solder paste is not used, the solder paste is applied on the heating surface. As long as it can be supplied separately, it is possible to obtain the same effect.

For example, instead of a grooved heating tool,
Even if a heating tool 904 having a shape as shown in FIG. 9A is used, the same effect can be obtained. The heating tool 904 has a plurality of heating surfaces 904a arranged at the same pitch as the package leads. For example,
Such a heating tool 904 can be easily manufactured by fixing a tungsten member or the like to be each heating surface 904a between two opposed tungsten plate members or the like. Alternatively, such a heating tool is also formed by forming a plurality of vertical holes arranged in a horizontal line in a band-like region near the center of a tungsten plate material, and then bending the regions on both sides thereof. be able to.

When the heating tool 904 is used, the heating surface 904a of the heating tool 904 is stored in the container 11 as shown in FIG. 9B in S201 of the flowchart shown in FIG. Solder paste 7
Then, in S202, as shown in FIG. 9B, the heating tool 904 pulled up from the container 111 is placed at a predetermined position, and the heating surface 904a of the heating tool 904 is heated.
After placing the package stack in front of the heating tool 904, the heating tool 904 is advanced to a predetermined position.
The heating surfaces 904a may be brought into contact with the tips of the lead rows of the package stack, respectively. After that, the heating process of the solder paste may be started according to the same procedure as when the above-mentioned grooved heating tool (see FIG. 1) is used. However, when the heating tool 904 is used, in order to reduce the temperature difference between the heating surfaces 904a before the main heating, the preheating time is adjusted according to the degree of heating of the heating surface 904a. Is required.

Further, in the case where the effect of cleaning the heated surface of the heating tool after soldering is to be improved, in particular, FIG.
It is recommended to use one of the two types of heating tool sets as shown in (1). On the heating surface 900a of the heating tool 900 of these two types of heating tool sets,
In any case, no uneven portion where the flux residue easily remains is formed at all. Instead, a heating tool 9
Thus, an auxiliary member for separating and supplying the solder paste to the heating surface 900a is required. For example, it may be the same pitch as the leads on the heating surface 9 of the heating tool 900.
A mold 901 for partitioning the space above the pattern 00a, a screen mold 903 having a linear pattern formed at the same pitch as the package leads, and the like. In addition, these auxiliary members 901,
Each of the mold thicknesses s ′ of 903 is set in accordance with the volume of the solder paste required to form a solder joint having a target thickness, and the mold widths d ′ are all mutually joined. In consideration of the positioning accuracy of the upper and lower leads of the lead row to be performed, the width is set slightly larger than the width D of the lead of the package.

When the heating tool set shown in FIG. 10A is used among these two types of heating tool sets, the heating tool 900 is previously set as shown in FIG. 11A.
The mold 901 is brought into close contact with the heating surface 900a of the
The space on the heating surface 900a of the No. 0 is partitioned. If you keep in such a state, after that, the heating tool with the groove described above
(Refer to FIG. 1).
That is, in S201 of the flowchart shown in FIG. 2, the solder paste 7 discharged from the dispenser 11 is supplied onto the heating surface 8a of the heating tool 8 as shown in FIG. As shown in (c), the space defined by the mold 901 is filled with the solder paste by running the spatula-shaped squeegee 12, and all excess solder paste attached to the mold 901 is removed. do it. Then, in subsequent S202, as shown in FIG.
By placing the package stack in front of the mold stack 901 and advancing the heating tool 900 together with the mold 901 to a predetermined position, the leading end of the lead row of the package stack is inserted into the gap partitioned by the mold 901. What is necessary is just to make it insert slightly. In this case, when the soldering is completed, the mold 901 is removed from the heating surface 900a of the heating tool 900 as shown in FIG.

On the other hand, when the heating tool set shown in FIG. 10B is used, S20 of the flowchart shown in FIG.
12, as shown in FIG. 12A, first, a screen mold 903 is brought into close contact with the heating surface 900 a of the heating tool 900, and an appropriate amount of the solder paste 7 is attached thereon, and then, as shown in FIG. As shown, the linear pattern formed on the screen die 903 may be transferred onto the heating surface 8a of the heating tool 8 by running the spatula-shaped squeegee 12 on the screen die 903. . Then, in S202, as shown in FIG. 12C, the screen die 903 is removed from the heating surface 900a of the heating tool 900, and the package laminate is placed in front of the screen die 903. Then, by advancing the heating tool 900 to a predetermined position, as shown in FIG.
What is necessary is just to make it slightly contact one solder pattern 7 transferred to 0. Here, “slightly contact” means “to the extent that the solder pattern 7 is not crushed,
That is, the ends of the lead rows of the package laminate are brought into contact with each other. " This is a consideration for preventing contact between the adjacent solder patterns 7.

In this embodiment, a resistance heating type heating tool is used, but it is not always necessary to use such a heating tool. For example, instead of this, a heating tool 80 of a cartridge heater detachable type as shown in FIG. 8A may be used. When the heating tool 81 is used, in S202 of the flowchart shown in FIG. 2, the heating tool 81 is advanced to a predetermined position A as shown in FIG.
After the end of the lead row of the package stack is inserted into the groove of the heating surface of the heating tool 81, in the following S203, as shown in FIG. Cartridge heater 81 may be inserted. This is because the preheating of the heating tool 81 is started by the contact between the tapered cartridge heater 81 and the inner surface of the tapered hole 80a of the heating tool 81. Then, in S205 after the main heating, the tapered cartridge heater 81 may be pulled out from the tapered hole 80a of the heating tool 81 as shown in FIG. Taper hole 80a of heating tool 81
This is because the main heating of the heating tool 81 is completed by pulling out the tapered cartridge heater 81 from the above.

[0038]

According to the soldering method of the present invention, a more reliable solder can be provided between a plurality of three-dimensionally arranged base materials without giving a thermal shock to the surroundings in a short time. Joints can be formed at once.

[Brief description of the drawings]

FIG. 1A is a front view of a resistance heating type heating tool according to an embodiment of the present invention, and FIG. 1B is a bottom view thereof.

FIG. 2 is a flowchart showing a procedure of a process of a soldering method according to an embodiment of the present invention.

FIG. 3A is a diagram for explaining a method of using a jig with a positioning pin, and FIG. 3B is a diagram for explaining a method of using a positioning device.

FIG. 4A is a perspective view of a package stack in which a plurality of packages are stacked, and FIG. 4B is a side view of a lead portion thereof.

FIG. 5 is a diagram showing a procedure for supplying a solder paste to a heating surface of the heating tool in FIG. 1;

FIG. 6A is a top view showing a state where a lead row of a package laminate is inserted into a heating surface of a heating tool,
(b) is the AA sectional view.

FIG. 7 is a diagram showing a soldering schedule according to one embodiment of the present invention.

FIG. 8 is a diagram for explaining a method of using a cartridge heater detachable heating tool according to an embodiment of the present invention.

FIG. 9 is a view for explaining a method of using the resistance heating type heating tool according to one embodiment of the present invention.

FIG. 10 is an external view of two types of heating tool sets.

FIG. 11 is a diagram for explaining how to use one heating tool set.

FIG. 12 is a diagram for explaining a method of using the other heating tool set.

FIG. 13A is a top view showing a state in which each lead row of the package laminate is brought into contact with each solder pattern printed on the heating surface of the heating tool, and FIG. -A
It is sectional drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Package 2A ... Jig 2B ... Holding jig 3 ... Package lead 4 ... Positioning pin 7 ... Solder paste 8 ... Resistance heating type heating tool 8a ... Heating surface of heating tool 8b ... Groove for filling solder paste DESCRIPTION OF SYMBOLS 11 ... Dispenser 12 ... Squeegee 14 ... Block material with fins 80 ... Heating tool of cartridge heater detachable type 81 ... Cartridge heater 500 ... Positioning device 500a ... Moving table 900 ... Resistance heating type heating tool 901 ... Form frame 903 ... Screen type 904: Resistance heating type heating tool

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Isamu Yoshida 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Hitachi, Ltd. Production Technology Research Laboratory (72) Inventor Ryuzo Fukao 1-88 Ushitora 1-chome, Uchitora, Ibaraki-shi, Osaka No. Within Hitachi Maxell, Ltd.

Claims (7)

[Claims] 1. A molten filler metal is caused to flow between base materials to be joined among a plurality of base materials arranged three-dimensionally to selectively join the plurality of base materials. A joining method, comprising: a filler material having a shape that contacts only a base material to be joined to each other among the plurality of base materials on a heating surface of a heating tool maintained at a temperature lower than a melting point of the filler material. A second step of bringing the heating tool and the plurality of base materials close to each other so that the plurality of base materials come into contact with a filler material on a heating surface of the heating tool; A third step of starting heating of the heating tool so that the filler material on the heating surface of the heating tool is melted, and after a predetermined heating time has elapsed, the surface temperature on the heating surface of the heating tool is increased Start cooling of the heating tool so that it is lower than the melting point of the filler material In a fourth step, after a predetermined cooling time has elapsed, the heating tool and the plurality of base materials are separated from each other so that the filler material solidified during the cooling time is separated from the heating surface of the heating tool. And a fifth step. 2. The bonding method according to claim 1, wherein the heating tool has a plurality of grooves overlapping a virtual path connecting only the base materials to be bonded to each other among the plurality of base materials. A heating tool having a heated surface is prepared, and a cream-like filler material is prepared as the filler material. In the first step, the inside of a groove of the heating surface of the heating tool is provided. A joining method comprising filling the filler material and attaching the filler material to a heating surface of the heating tool. 3. The joining method according to claim 1, wherein a creamy filler material is prepared as the filler material, and a base material to be bonded to each other among the plurality of base materials is prepared. A screen mold having a screen pattern having a shape overlapping with a virtual path connecting only between them is prepared, and in the first step, the screen pattern of the screen mold is formed by the filler material on the heating surface of the heating tool. A bonding method comprising transferring the filler material onto a heating surface of the heating tool and transferring the filler material onto the heating surface of the heating tool. 4. The bonding method according to claim 1, wherein the heating tool has a heating surface divided into divided regions that are in contact only with the base material to be bonded to each other among the plurality of base materials. A tool is prepared, and a creamy filler material is prepared as the filler material. In the first step, the filler material is divided into divided regions on the heating surface of the heating tool. A bonding method characterized by attaching. 5. The joining method according to claim 1, wherein a substance having a temperature lower than a melting point of the filler material is brought into contact with the heating tool, and the heating tool is connected to the heating tool. A joining method, characterized by cooling. 6. A method for manufacturing an electronic device in which a plurality of electronic components are stacked, and an electronic device in which leads between the plurality of electronic components to be connected to each other are joined is provided. Stacking the components, bonding the plurality of electronic component leads to each other in a state where the plurality of electronic components are stacked on a heating surface of a heating tool maintained at a temperature lower than the melting point of the filler material. Adhering a filler material having a shape that comes into contact only with the base material to be formed; and Approaching the electronic component of, and heating the heating tool so that the filler material on the heating surface of the heating tool is melted, and after a predetermined heating time has elapsed, Starting to cool the heating tool so that the surface temperature on the heating surface of the heating tool is equal to or lower than the melting point of the filler material; and after a predetermined cooling time has elapsed, a predetermined heat radiation time has elapsed. Manufacturing the electronic device, further comprising: separating the heating tool and the plurality of electronic components so that the filler material solidified during the heat radiation time is separated from the heating surface of the heating tool. Method. 7. A soldering heating tool having a heating surface for supplying heat for melting said filler material into a creamy filler material, wherein said heating surface is filled with said filler material. A heating tool for soldering, characterized in that the groove is formed.