JPH11261211A - Soldering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a soldering method by which the lands of two or more circuit boards can be soldered to each other by combining the circuit boards in a double cross state and the fluctuations of the joining strength and reliability can be eliminated. SOLUTION: In a soldering method in which conductor patterns are joined to each other by performing soldering at every set of lands to be joined, one or more sets of lands 11a and 11b to be joined are arranged at the corners of a double cross through a process of forming solidified solder 6 on the lands 11a and 11b for joining conductor patterns and combining circuit boards in a double cross state and the lands are joined to each other in one bodies at every set by melting the solidified solder 6 on the lands 11a and 11b arranged at the corner sections of the double cross by heating in a process of mounting electronic parts on circuit boards 1a and 1b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering method in which two or more circuit boards are combined in a grid pattern, and lands of the combined circuit boards are soldered to join conductor patterns to each other. In particular, the present invention relates to a soldering method capable of eliminating variations in bonding strength and reliability at a soldered portion and improving working efficiency.

[0002]

2. Description of the Related Art Conventionally, for example, after mounting electronic components on a circuit board in a surface mounting step or a wave soldering step, the circuit board is cut into individual pieces, and the cut individual circuit boards are separated. Combine in a girder shape. In addition, in order to join the conductor patterns to each other in the individual cut circuit boards, it is assumed that lands are formed in advance at respective joining portions of the circuit boards.

After this assembling, the thread solder is heated and melted while feeding or automatically supplying the thread solder to the tip of the soldering iron at the land forming position at the corner of the girder. By joining, the conductor patterns are joined to each other.

[0004]

However, in the case of the above-mentioned conventional soldering method as described above, there are the following problems.

(1) Since the soldering is performed one point at a time, the time required for the soldering is too long.

(2) A part of the solder supplied to the tip is adhered to the tip and remains, and the supplied solder is not entirely supplied to the land but the amount of solder supplied to the land. And the shape of the solder fillet varies.

(3) Since the amount of solder supplied to the lands varies, the bonding strength and reliability at the soldered portions also vary.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. It is an object of the present invention to combine two or more circuit boards in a grid pattern and then solder between lands of the combined circuit boards. It is an object of the present invention to provide a soldering method which can eliminate variations in bonding strength and reliability at a soldered portion and improve work efficiency in a soldering method for attaching conductor patterns to each other.

[0009]

According to the first aspect of the present invention, since the conductor patterns of two or more circuit boards are joined to each other, a land is previously provided for each joint portion of each circuit board. Forming and combining the respective circuit boards in a cross-girder shape and arranging at least one set of lands to be joined at the cross-girder corners, and then performing soldering for each set of lands to be joined, In the soldering method of joining the conductor patterns to each other, in a step of mounting an electronic component on a circuit board, to form a solidified solder on the land for the conductor pattern joining, after forming the solidified solder,
Through the step of combining the circuit boards in a cross-girder, one or more sets of lands to be joined are arranged at the cross-girder corners, and formed on the one or more sets of lands arranged at the cross-girder corners The soldering method is characterized in that the solidified solder that is present is heated and melted together to be integrated with each other, and both lands of each set of lands are joined to each other.

According to the invention described in claim 1 of the present application, for example, in a surface mounting step or a wave soldering step, after obtaining a mounting structure of an electronic component including a portion where solidified solder is formed, After cutting the circuit board into individual pieces, combining the individual cut circuit boards in a cross-girder shape, heat and melt the solidified solder at the land formation position for conductor pattern joining to form a fillet for conductor pattern joining Since the conductor patterns are joined to each other in a series of steps of joining the conductor patterns to each other, the following effects will be obtained.

(1) Before the soldering step for joining the conductor patterns to each other, the solder can be supplied onto the lands by a method such as printing or dispensing in advance, so that the variation in the amount of supplied solder is small.

(2) Since the variation in the amount of supplied solder is reduced, the bonding strength and reliability at the land forming position for connecting the conductor pattern are kept constant, and stable soldering can be performed.

(3) For example, by using a multi-type tip or a wide-type tip, the lands at each joining position can be soldered together by batch heating, so that the conductor patterns are joined together. The lead time of the soldering process for performing the soldering can be shortened.

(4) In the surface mounting step or the wave soldering step, when electronic components are mounted, solder is preliminarily coated on the lands for joining the conductor patterns, so that the conductor patterns are joined together. Prior to performing the soldering step, the lands for joining the conductor patterns are not oxidized by reflow and are not contaminated during the wave soldering.

[0015] The invention according to claim 2 of the present application is characterized in that the solidified solder is formed by applying a cream solder on the land for bonding the conductor pattern by a printing method, and then heating and melting the cream solder. A soldering method according to claim 1.

According to the invention as set forth in claim 2 of the present application, since the variation in the amount of supplied solder is reduced, the bonding strength and reliability at the land forming position for bonding the conductor pattern are kept constant. Stable soldering will be achieved.

The invention according to claim 3 of the present application is characterized in that the solidified solder is formed by applying a cream solder on the land for bonding the conductor pattern with a dispenser and then heating and melting the cream solder. Item 1 is a soldering method according to item 1.

According to the third aspect of the present invention, since the variation in the amount of supplied solder is reduced, the bonding strength and reliability at the land formation position for bonding the conductor pattern are kept constant. Stable soldering will be possible.

In the invention according to claim 4 of the present application, the cross-girder corner portion is formed by heating and melting the solidified solder.
4. The soldering method according to claim 1, wherein the soldering method is inclined with respect to a horizontal plane.

According to the invention as set forth in claim 4 of the present application, the heat-fused solder is formed into a fillet shape while always flowing toward the vertex position of the corner of the girder. Stable soldering will be achieved.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the soldering method of the present invention will be described below in detail with reference to the drawings.

In the soldering method according to the present invention, as described above, since the conductor patterns of two or more circuit boards are joined to each other, lands are respectively formed in advance at each joint portion of each circuit board. Further, by assembling the respective circuit boards in a cross-girder shape and arranging at least one set of lands to be joined at the corners of the cross-girder, performing soldering for each set of lands to be joined, It is applied to a soldering method for joining conductor patterns to each other.

In this type of soldering method, after the electronic components are mounted in the surface mounting step or the wave soldering step, the conductor patterns are joined to each other.

However, in the surface mounting step or the wave soldering step, the above-described conventional problems occur unless any measures are taken to join the conductor patterns to each other.

Therefore, in a preferred embodiment of the present invention,
Using the surface mounting technology, as shown in the process flow diagram of FIG. 1, first, the cream solder printing process (1) is performed, then the component mounting process (2) is performed, and then ,
When the electronic component 3 is mounted on the circuit board 1 by performing the reflow process (3), the following measures are taken. At the stage of the steps (1) to (3), the circuit board 1
The circuit board is divided into a circuit board 1a and a circuit board 1b by individual cutting described later.

That is, in this embodiment, in the cream solder printing step, when the cream solder 2 is applied on the circuit board 1 at the position (land) where the electronic component is to be mounted by the printing method, the conductor which is not mounted with the component is not used. The cream solder 3 is also applied on the lands for pattern bonding.

In the following component mounting step, the circuit board 1 is mounted.
The cream solder 2 is applied to an appropriately selected position above, and the electronic component 4 is arranged at this application position.

In the subsequent reflow step, the cream solders 2 and 3 are melted by heating and solidified. A fillet 5 is formed by heating and melting and solidifying the cream solder 2, and a mounting structure of the electronic component 4 in which the electronic component 4 is mounted on the circuit board 1 can be obtained. At the same time, melting cream solder 3
By the solidification, the solidified solder 6 can be formed on the land for bonding the conductor pattern. In this step, a solidified solder can be formed on the land for bonding the conductor pattern by using a wave soldering technique.

After obtaining the mounting structure of the electronic component 4 including the portion where the solidified solder 6 is formed, the circuit board 1 is cut into individual pieces. Note that the individual circuit boards 1a and 1b, which have been cut individually, are assumed to have lands formed in advance at each joint portion of each circuit board in order to join the conductor patterns to each other.

Next, the individual circuit boards 1 cut into individual pieces
The substrate assembling step (4) is performed using a and 1b. In this board assembling step, the circuit boards 1a and 1b, which have been cut individually, are combined in a cross-girder shape, and one or more pairs of lands to be joined are arranged in the cross-girder corner X. FIG. 2 shows a state in which the solidified solder 6 is formed on the lands 11a and 11b of the cross corner X, respectively.

After assembling the individual circuit boards cut into individual pieces in a cross-girder shape, as shown in FIG. 2, a flux 14 is applied to the land formation position of the cross-girder corner portion X, and then the land formation position is changed. Heating is performed to perform the fillet forming step (5) for joining the conductor patterns between the substrates. In the fillet forming step, the conductor patterns are joined to each other by forming a fillet 7 by performing soldering for each set of lands to be joined.

For example, as shown in FIG. 3A, the arm 1 of the robot 9 is set with the soldering iron 8 as an attachment.
0, and as shown in FIG. 2B, the lands 11a, 1 arranged on the corners X of the circuit boards 1a, 1b.
An iron tip 8a of the soldering iron 8 is arranged close to the target 1b, and the solidified solder 6 on the lands 11a and 11b is heated and melted by the iron tip 8a.

Alternatively, as shown in FIG.
The R device 12 is attached to the arm 10 of the robot 9 as an attachment, and as shown in FIG. 2B, lands 11a,
A heat radiating portion 12a of the IR device 12 is disposed close to the target 11b, and the solidified solder 6 on the lands 11a and 11b is heated and melted by radiant heat radiated from the heat radiating portion 12a.

Alternatively, as shown in FIG. 5 (a), the hot air discharging device 13 is attached to the arm 10 of the robot 9 as an attachment, and as shown in FIG. 5 (b), the grid angles of the circuit boards 1a, 1b. The target is set on the lands 11a and 11b arranged in the section X and the hot air discharging device 1 is set.
The third nozzle 13a is arranged in close proximity, and the solidified solder 6 on the lands 5a and 5b is heated and melted by hot air discharged from the nozzle 13a.

As described above, when the solidified solder 6 on the lands 11a and 11b is melted, a fillet 7 is formed so as to straddle the lands 11a and 11b as shown in FIG. The conductor patterns can be joined. As a result, the conductor patterns are joined to each other. In any case of FIGS. 3, 4, and 5, when the solidified solder 6 on the lands 11a and 11b is heated and melted,
The girder corner X is maintained in a state of being inclined with respect to the horizontal plane. Therefore, the heated and melted solder is always
Is formed in a fillet shape while flowing toward the apex position, so that stable soldering can be achieved.

When the conductor patterns are joined to each other in a series of steps as described above, the following effects are obtained.

(1) Before the soldering step for joining the conductor patterns to each other, the solder can be supplied onto the lands 11a and 11b by a method such as printing and dispensing in advance.
Small variation in solder supply.

(2) Since the variation in the amount of supplied solder is reduced, the bonding strength and reliability at the land forming position for the conductor pattern bonding are kept constant, and stable soldering can be performed.

(3) For example, using a multi-type tip 8A as shown in FIG. 7 or a wide-type tip 8B as shown in FIG.
Since the 11N lands 11a and 11b can be soldered by batch heating, the lead time of the soldering process can be shortened.

(4) In the surface mounting step or the wave soldering step, when electronic components are mounted, solder is preliminarily coated on the lands 11a and 11b for connecting the conductor patterns. Before the soldering step for joining is performed, the lands 11a and 11b for joining the conductor patterns are not oxidized by reflow and are not contaminated during the wave attachment.

[0041]

As is clear from the above description, according to the present invention, after two or more circuit boards are combined in a grid pattern, the lands of the combined circuit boards are soldered to each other, and the conductor patterns are joined together. In the soldering method for joining the components to each other, it is possible to provide a soldering method that can eliminate the variation in the joining strength and the reliability at the soldered portion and improve the working efficiency.

[Brief description of the drawings]

FIG. 1 is a process flow chart schematically showing a soldering method according to the present invention.

FIG. 2 is a view showing a state in which solidified solder is formed on each of a pair of lands at the corners of the girder.

FIG. 3 is an explanatory diagram of an embodiment in which a soldering iron is used to solder-connect conductor patterns between substrates.

FIG. 4 is an explanatory diagram of an embodiment in which an IR device is used to solder-connect conductor patterns between substrates.

FIG. 5 is an explanatory view of an embodiment in which a hot air discharging device is used to solder-connect conductor patterns between substrates.

FIG. 6 is a diagram showing a state of solder connection of conductor patterns between substrates.

FIG. 7 is a diagram showing an example of another embodiment of a soldering iron.

FIG. 8 is a view showing another example of another embodiment of the soldering iron.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 1a, 1b Circuit board cut into pieces 2, 3 Cream solder 4 Electronic component 5 Fillet 6 Solidified solder 7 Fillet 8 Soldering iron 8a Iron tip 9 Robot 10 Arm 11a, 11b Land 11A-11N Joining position 12 IR device 12a Radiator 13 Hot air release device 13a Nozzle 14 Flux X

Claims (4)

[Claims] In order to join the conductor patterns of two or more circuit boards to each other, lands are respectively formed in advance at each joint portion of each of the circuit boards, and the circuit boards are combined in a cross-shaped manner and joined. A soldering method for joining the conductor patterns to each other by arranging at least one set of lands to be set at the corners of the girder and then soldering each set of lands to be joined. In the step of mounting an electronic component, a solidified solder is formed on the land for bonding the conductor pattern, and after the formation of the solidified solder, the circuit boards are combined in a cross-girder shape. At least one set of lands is arranged at the corner of the girder, and the solidified solder formed on the at least one set of lands arranged at the corner of the girder is heated and melted together to be integrated with each other. Orchid A method of soldering, wherein both lands of each node are joined to each other. 2. The soldering method according to claim 1, wherein the solidified solder is formed by applying a cream solder on the land for joining the conductor pattern by a printing method, and then heating and melting the cream solder. 3. The method according to claim 1, wherein the solidified solder is formed by applying a cream solder on a land for bonding the conductor pattern by a dispenser and then melting the solder by heating.
The soldering method described in 1. 4. The soldering method according to claim 1, wherein the crossed corner is inclined with respect to a horizontal plane when the solidified solder is heated and melted.