JPH06326450A - Soldering method - Google Patents

Abstract

PURPOSE:To provide a soldering method which can cope with an electronic component provided with pins disposed large in pitch or even a large number of pins disposed narrow in pitch and enables a circuit board to be enhanced in degree of freedom of design and process. CONSTITUTION:In a soldering method wherein the electrodes of an electronic component and a circuit board are soldered together, a solder paste filling process wherein solder paste is fed to a solder paste transfer member 2 provided with a recess 1 formed corresponding to the electrode of a circuit board and filled into the recess 1 is provided. A transfer process wherein the electrode of an electrical circuit component is brought into contact with solder paste filled into the recess 1, whereby solder paste filled in the recess 1 is transferred to the electrode of an electrical circuit component, a placing process wherein the electrode of an electrical circuit component with the transferred solder paste is placed on the electrode of a circuit board, and a fusing process wherein solder paste is melted by heating to solder the electrodes of an electrical circuit component and a circuit board together are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for soldering an electric circuit component mounted on a circuit board, and more particularly to a soldering method suitable for surface mounting.

[0002]

2. Description of the Related Art Conventionally, as a method for electrically connecting an electric circuit component onto a circuit board, a brazing method such as soldering, a mechanical crimping method, a method using a connector, etc. are known. There is. Among these, the soldering method is generally used because of its high productivity. Specifically, the flow soldering method, the reflow soldering method using screen printing or precoating, the robot soldering method, etc. are used. Has been.

The flow soldering method is a soldering method in which one surface of a circuit board on which an electric circuit component is temporarily mounted is dipped in molten solder, and it can be processed at a relatively high speed. It has been pointed out that if the pitch is less than about 0.65 to 1.27 mm, many defects such as solder bridges occur, resulting in difficulty in good soldering. Furthermore, since electric circuit components with poor heat resistance cannot be immersed in molten solder at high temperature, electric circuit components with poor heat resistance must be mounted on the back side of the circuit board on which the solder is immersed, and It has been pointed out that there is a lack of freedom.

Next, reflow soldering uses screen printing and was developed to eliminate the above drawbacks. FIG. 14 is a side view showing how solder paste is supplied in the reflow soldering method.
In this figure, a circuit board 8 is placed and fixed on a base 103, and a solder paste 3 (shown by a solid line in the figure) is placed on a screen mask 101 on which a predetermined wiring pattern is formed. The solder paste 3 is moved in the direction of the arrow Y while applying a constant force, and the solder paste 3 is extruded downward through the screen opening 102 to print the solder paste 3 on the electrodes of the circuit board 8.

After that, an electric circuit component is placed on the electrodes of the circuit board 8, the solder paste is heated and melted, and reflow soldering is performed to obtain a desired mounted board. Here, as the reflow soldering heating and melting method, there are a method using infrared rays and far infrared rays, a method using a hot air method using hot air, and a method using a vapor phase method using latent heat of vaporization of an inert solvent. A method using a hot ram or a hot plate method using a heating member, a method using a heat source such as YAG, a CO ₂ laser, or the like is known.

On the other hand, a pre-coating method is known as a pre-soldering method in which solder is previously supplied onto the electrodes 9 of the circuit board 8. A typical example thereof is precoating with a hot gas leveler in which the circuit board is immersed in a molten solder bath and hot gas is blown during pulling to remove excess solder on the electrodes. Next, as a typical example of the robot soldering method, see FIG. 17, which is a side view showing the schematic configuration of FIG. 16 and an enlarged perspective view of the essential parts of FIG. 16, showing an appearance around the tip of FIG. And state. In both figures, an electrode 6 provided integrally with an electric circuit component 5 is placed on an electrode 9 of a circuit board 8 in a contact state, and a tip 1 heated to the electrode 6 of the electric circuit component 1 is placed.
The wire solder 106 is fed in the direction of arrow H in FIG.

In the above structure, the electrode 6 of the electric circuit component 5 and the electrode 9 of the circuit board are soldered by the solder melted at the tip 105. Thus, the soldering tip 105 is continuously slid in the direction of the arrow T (FIG. 17) while being in contact with the electrode 6 of the electric circuit component, the electrode 9 of the circuit board, or the circuit board 8 to perform soldering. It is a method of attaching.

[0008]

However, the above-mentioned conventional soldering methods have the following drawbacks.
First, among screen printing methods, a separate printing method in which a solder paste is supplied to each electrode (printing is performed using a screen mask having an opening corresponding to each electrode, and the printed solder paste is Each time the solder paste is applied), the screen becomes smaller as the electrode pitch (distance between the centers of adjacent electrodes) of the electric circuit parts and the circuit board becomes 0.65 mm and 0.5 mm. The opening area of the mask is also small, but when the opening area is small in this way, the solder paste is hard to come off from the mask, and the printability deteriorates. As a result, the variation in the amount of solder paste printed for each electrode of the circuit board becomes large, resulting in inter-electrode bridges, unsoldering (described later), and the like after reflow, which deteriorates the reliability of bonding. In addition, there is a drawback that it becomes more difficult to set conditions for solder paste printing such as screen mask tension, gap between mask and circuit board, squeegee direction, angle, speed, printing pressure, and the amount of solder paste used. is there.

For example, when the gap between the screen mask and the circuit board is large, for example, the plate separation immediately after passing the squeegee becomes rapid, so that the solder paste adheres to the mask and the printing pattern In the case of partial peeling (printed material is partially chipped, printing thickness is different, solder paste amount is partially different), unsoldered after reflow soldering (solder amount This is one of the causes of shortage or unconnected solder. (Edited by Nikkan Kogyo Shimbun, "91 SMT.
Soldering technology "Nikkan Kogyo Shimbun P37-43 19
On the other hand, if the printing pressure of the squeegee is too high, the mask will deform and the sealing performance of the mask will deteriorate, and the solder paste will spread from the opening of the mask to different surfaces. , Bleeding is likely to occur in the printed area around the electrode part on the circuit board, and bridges are likely to occur after reflow soldering (press journal edition "Surface mount technology" press journal P94-9
8, 1990 autumn issue).

Therefore, a method called one-character printing is used as a method for improving the soldering failure by the above-mentioned separate printing method. According to this one-character printing method,
Rather than applying solder paste to each electrode on multiple electrode parts of the circuit board, the solder paste is applied across the electrodes, and the opening area of the screen mask is large compared to the separate printing method described above. Therefore, there is an advantage that the printability is improved.

However, even with this one-character printing method,
When heating and melting the solder paste after printing,
Since the solder existing between the adjacent electrode parts is difficult to be uniformly separated into the adjacent electrode parts, a solder bridge, unsolder, or even solder that cannot be attracted to the electrode parts remains between the adjacent electrodes. However, there is a problem that a solder ball becomes a ball-shaped solder.

Furthermore, when it is necessary to print at the same time a mixture of these narrow-pitch electric circuit components and a relatively large portion, it is necessary to print the narrow-pitch electric circuit components with a very small inter-electrode dimension. In the screen mask of, since the amount of solder paste in a relatively large part may be insufficient due to the mesh, it may be necessary to print with the screen mask partially changed in thickness. If the thickness is partially changed, there is a problem that defective printing is likely to occur at different portions and defective bonding is likely to occur.

Next, since the hot gas pressure acting on each electrode of the circuit board cannot be set uniformly in the precoating method called the hot gas leveler, the variation in the solder thickness becomes as large as several μm to several tens μm. It becomes impossible to absorb the variation in the electrode shape of the electric circuit parts. For example, in the case of a QFP (a type of electric circuit component, which will be described later) having a pitch of about 0.5 mm as shown in FIG. 15, for example, the height variation of the electrode leads is about 100 μm, and the thickness variation of the solder 16 is 40 μm. If it was about
Even when the solder is sufficiently melted, the solder 16 and the electrode lead 6 are separated by a maximum of 60 μm, which causes a problem that soldering cannot be performed.

Next, in the robot soldering method, since the amount of melted thread solder at the tip is often unstable, 0.8 m
If the pitch is less than about m, many defects such as solder bridges and unsolders occur. That is, as shown in FIG. 17, when the tip 105 is continuously slid (in the direction of the arrow T) while keeping the tip 105 in contact with the electrode 6 or the circuit board, the narrow-pitch electrode lead 6 is thin and weak. The electrode is caught at the tip of the tip, and the electrode lead 6 is bent as shown in the drawing, causing a defect. Therefore, it is conceivable to finely adjust the contact pressure and increase the speed, but in order to do so, a high-sensitivity sensor and a high-speed motor are required, resulting in an increase in the cost of the entire robot.

As described above, for soldering of a narrow pitch electric circuit component having a pitch of about 0.5 mm or less, for example, in any of the above-mentioned conventional methods, a minute amount of solder paste is supplied in a fixed amount, and a solder bridge or solder is used. It has been extremely difficult to prevent the generation of balls and to surely perform the operation without causing defects such as unsoldered solder. Therefore, the present invention has been made in view of the above circumstances, and the purpose thereof is that large-pitch soldering is, of course,
An object of the present invention is to provide a soldering method which can cope with a narrow pitch and a large number of pins, and can increase the degree of freedom in designing a circuit board and the process.

[0016]

In order to solve the above problems and achieve the object, a method for soldering an electrode portion of an electric circuit component and an electrode portion of a circuit board according to the first aspect of the present invention is A method of soldering and connecting the electrode portion of an electric circuit component having at least one or more electrode portions and the electrode portion of a circuit board having at least one or more electrode portions,
Filling a solder paste in the recess of a solder paste transfer member having one or more desired recesses corresponding to the electrode portions of the circuit board, and the solder paste corresponding to the electrodes of the electric circuit component, respectively. And transferring the solder paste in the concave portion to the electrode portion of the electric circuit component, and the electrode portion of the electric circuit component having the solder paste to the corresponding circuit board tail electrode portion. It is characterized by including at least a step of placing and a step of heating and melting the solder paste to solder the electrode portion of the electric circuit component and the electrode portion of the circuit board.

According to a second aspect of the present invention, there is provided a method for soldering an electrode portion of an electric circuit component and an electrode portion of a circuit board according to the first aspect, wherein at least one portion of the concave portion of the solder paste transfer member is repelled. 1 of water-based or oil-repellent materials
It is characterized in that it is composed of one or more kinds of materials. A soldering method for an electrode portion of an electric circuit component and an electrode portion of a circuit board according to a third aspect of the present invention is the first aspect of the invention, in which the solder paste of the electric circuit component is transferred to the electrode portion of the circuit board. It is characterized in that the surface side is placed and soldering is performed.

[0018]

According to the method of soldering the electrode of the electric circuit component and the electrode of the circuit board of the present application, a solder paste transfer member having a recess having a desired shape corresponding to the electrode of the electric circuit component is prepared, and the recess is formed. Fill the inside with solder paste.
The electrodes of the electric circuit parts are brought into contact with the filled solder paste, and the desired solder paste is transferred onto the electrodes for each pin, so that a fixed amount can be supplied, and then contact placement is performed corresponding to the electrodes on the circuit board. After that, by performing heat reflow soldering, it is possible to perform soldering with high reliability without solder bridges, solder balls, or unsoldered solder.

From this, when a large-pitch component and a narrow-pitch multi-pin component are mixed, the large-pitch component is printed with a solder paste by a known method, and then the narrow-pitch multi-pin in which the solder paste is transferred to the electrode. This effect becomes remarkable by the method of placing the parts and reflowing them. The control of the supply amount by transfer can be easily performed by using a member having a different recess size.

Further, by coating the surface of the concave portion with a water-repellent or oil-repellent material or the like, the transfer can be surely carried out, and the quantitative supply becomes possible. Also, in the electrode part of the electric circuit component, the surface to which the solder paste is transferred is brought into contact with and placed on the electrode part of the circuit board, and then the solder paste is heated and melted, so that solder bridges and solder balls can be formed by soldering. The lessening effect increases.

Furthermore, the situation in which the electric circuit component can be placed on either one or the other surface of the circuit board, and after the electric circuit component is soldered, another electric circuit component is further soldered. Even if there is such a problem, the present invention provides a soldering method in which the degree of freedom in the design and process of a circuit board is increased because soldering can be performed easily.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing a process according to the first embodiment of the present invention. The figure shows an intermediate step of transferring the solder paste to and mounting it on a circuit board. 2 is a schematic cross-sectional view taken along the line XX of FIG. 1 and shown together with a squeegee.

First, in FIG. 2, the paste transfer member 2 is made of polytetrafluoroethylene (PTFE), and the recesses 1 are formed as shown in the drawing to match the pitch of the electrodes of the electric component. . One side of the opening upper surface 18 of the recess 1 is a 0.25 mm square, one side of the bottom surface 19 of the recess 1 is a 0.15 mm square, and the depth is from 0.05 to.
The side surface 21 of the recess 1 is formed in the range of 0.3 mm.
Has a slope. Next, with further reference to FIG.
Recessed portion 1 of paste transfer member 2 formed as described above
A known screen printing method may be used as a filling method for filling the solder paste 3 with the solder paste 3. Specifically, the solder paste 3 is placed on the left end surface of the solder paste transfer member 2 and then the squeegee 4 is added. Is closely attached to the solder paste transfer member 2 and moved in the direction of the arrow Y in the drawing, so that the solder paste 3 is filled in the recess 1.

The squeegee 4 used in this way is provided with skirts 12 for returning the solder paste spread on both ends of the squeegee 4 to the center direction, and the squeegee speed for moving the squeegee 4 is 1 to 700 mm / sec. The pressure is 0.1 to 4.5 kg / cm ² , the squeegee angle is 0 to 60 °, and the squeegee diagonal printing angle is ± 45 °. Solder paste 3 is made of Nihon solder, product name RX362-CR5F, (solder composition Su62%, Pb
Good results were obtained by using 36%, Ag 2% φ25-45 μm spherical solder).

Next, FIG. 3 is a schematic sectional view in which an electric circuit component is aligned with the solder paste transfer member 2 obtained through the steps shown in FIGS. In FIG.
The electric circuit component 5 is vacuum-sucked and held by the suction holder 7, the electric circuit component 5 and the solder paste 3 in the recess 1 are brought close to each other, and the electrode 6 of the electric circuit component corresponds to the solder paste 3 in each recess 1. The alignment is performed as described above. This alignment is performed between the alignment mark 20 marked on the solder paste transfer member 2 and the plurality of electrodes 6 of the electric circuit component. This electric circuit component 5 is a 0.5-mm pitch 24-pin Quad
Flat Package (QFP) is used.

The electric circuit component 5 held as described above
Is lowered in the downward direction (arrow D) as shown in the schematic cross-sectional view of the state in which it is in contact with the solder paste, and the electrode 6 of the electric circuit component 5 and the solder paste 3 are brought into contact with each other. To be done. The contact pressure at this time is 0.1 to 5
The range was set to 00 g / mm ² . Next, as shown in an external perspective view of FIG. 5 and a sectional view of an essential part of FIG. 6, the electric circuit component 5 contacted with the solder paste 3 is substantially perpendicular to the bottom surface of the recess 1 (direction of arrow U). ), The solder paste 3 in the recess 1 is transferred onto the electrode 6 of the electric circuit component. The rising speed at this time is 0.1mm-3
The measurement was performed in the range of 00 mm / sec.

Next, in FIG. 7, which is a schematic cross-sectional view showing a state where the electric circuit component and the circuit board are aligned, the electrode portion 6 on the surface side on which the solder paste 3 is transferred in the electric circuit component 5 is attached to the circuit board. Positioning is performed by facing the electrode 9. This alignment is performed by using the mark 20 as a mark in a state where the solder paste 3 on the electrode 6 of the electric circuit component and the electrode 9 of the circuit board are not yet in contact with each other. This circuit board 8 is an NEM having electrodes with 0.5 mm pitch and 24 pins.
A standard glass epoxy substrate CEM-3 was used.

Thereafter, as shown in the schematic cross-sectional view of the state in which the electric circuit component of FIG. 8 is placed on the circuit board, the electric circuit component 5 after alignment is lowered (in the direction of arrow D in FIG. 7), It was placed on the electrode 9 of the circuit board and the adsorption of the adsorption holder 7 was released. After that, the circuit board 8 on which the electric circuit component 5 is mounted is melted with the solder paste 3 by a well-known surface mounting technique using far infrared rays and hot air combined heating reflow method,
Soldering of the electrode 6 of the electric circuit component and the electrode 9 of the circuit board is completed.

Here, the shape of the recess 1 of the solder paste transfer member is such that one side of the opening upper surface 18 of the recess 1 is 0.25 mm.
Good results were obtained with the square shape, the side of the bottom surface 19 of the recess being 0.15 mm, and the depth being in the range of 0.05 to 0.3 mm. Any shape may be used as long as it is a concave shape of the transfer member that can be set to the amount.

Although PTFE is used as the material of the solder paste transfer member 2 in the above embodiment, the material is not limited to such an organic material, and a metal material or an inorganic material may be used. For example, in the case of an organic material, fluororesin tetrafluoroethylene (PFA, FEP, EPE, ETF)
E), polychlorotrifluoroethylene (PCTF
E), chlorotrifluoroethylene (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), silicone resins, polypropylene resins, polyethylene resins and the like.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 9 is an external perspective view according to the second embodiment. The components already described in the description of the first embodiment are designated by the same reference numerals, and different parts will be described. The shape is not a smooth surface as shown, but a groove 17 is formed. Further, the material of the solder paste transfer member 2, the number of times of printing and transfer, and the front and back relationship of the solder paste transfer surface of the electrode portion of the electric circuit component are reversed.

That is, FIG. 1 which is a sectional view taken along the line XX of FIG.
As shown in FIG. 0, the shape of the solder paste transfer member 2 has a groove 17 in the center thereof and a radius of 0.1 to 0.1.
Twelve 0.15 mm hemispherical recesses 1 are formed. In addition, after forming a hemispherical recess 1 on a stainless steel SUS 304, a coating layer 11 of a fluorine-based resin PFA is provided on the solder paste printing surface and the surface of the recess 1.

The coating layer 11 is formed in a film thickness range of 10 to 30 μm by baking the fluororesin attached in the dispersion state at about 300 ° C. The solder paste transfer member 2 formed as described above is shown in FIG.
As shown in FIG. 3, printing is performed by moving the squeegee 4, and the mark 20 is used as a mark for positioning. Next, as shown in FIG. 10, the electric circuit component 5 is turned upside down in order to contact the solder paste on the surface of the electric circuit component 5 opposite to the electrode portion 6, and the upper surface 15 of the electric circuit component is turned down. After the transfer, the electric circuit component is separated from the paste transfer member 2 and the solder paste 3 is transferred to the electrodes 6 of the electric circuit component 5 arranged in parallel with each other. After that, the electric circuit component 5 is pulled up, rotated 90 degrees, and then moved downward to transfer the solder paste 3, thereby transferring the solder paste 3 to the surfaces in two directions at right angles.

Next, the electric circuit component 5 is turned upside down so that the upper surface 15 of the electric circuit component faces upward, and the electric circuit component 5 is positioned by the same method as described above. As shown in FIG.
Place on top. After that, reflow soldering is performed by the same method as in the first embodiment. Here, SUS304 was used as the material for forming the solder paste transfer member 2, but the material is not limited to SUS, but Fe-based, Al, Cu, Ni, M.
o, W of the metal material and its alloy material and S _i O _2, B ₂ O
Ceramics such as ₃ , Al ₂ O ₃ and the like, inorganic materials such as diamond and glass and organic materials may be used.

Further, although PFA was used for the above-mentioned coating layer 11, the present invention is not limited to this, and other fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene (FEP, EPE, ETFE), Polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF)
And silicone-based resins such as polypropylene-based resins, polyethylene-based resins, or silane coupling agents (fluorine-based silane compounds, etc.), titanium coupling agents, nonionic surfactants, natural waxes such as carnauba wax A material excellent in water repellency and oil repellency such as nonionic wax emulsion and natural fatty acid amide derivative may be coated.

The coating layer 11 is deposited in a dispersion state and baked. However, the coating layer 11 may be formed by a method such as dip coating, vapor deposition, spraying, brushing, laminating, etc., natural drying, heating. It is preferable to use a drying method suitable for each of drying and the like. Further, in the second embodiment, the 24-pin QFP is used as the electric circuit component 5, but Tape Automated Bonding is used.
Package by (TAB) or Shrink Small
l Outline Package (SSOP), T
hin Small Outline Package
(TSOP), Small Outline J-le
Package I such as added Package (SOJ)
Surfac for C, chip resistors, chip capacitors, etc.
The surface mount component of eMount Device (SMD) may be used, and the number of pins is 24. However, the number of pins is not limited to this, and 100 to 1000 pins may be used.

Further, although CEM-3 was used for the circuit board 8, the present invention is not limited to this, and GP of a glass polyisid board is used.
Y, glass epoxy board FR-4 / G-10, glass paper epoxy board CEM-1, paper epoxy board FR-
3. Paper phenolic board FR-1, FR-2, XXXP
A printed circuit board such as a C / XPC or a glass fluororesin board or a flexible printed circuit board may be used.

The contact pressure is 0.1 to 5 in this embodiment.
Although the pressure was set to 00 g / mm ^2, it is preferable that the pressure is such that at least one surface of the electrode of the electric circuit component is embedded in the solder paste. Moreover, the rising speed of the electric circuit parts was continuously set within the range of 0.1 to 300 mm / sec this time, but in order to further stabilize the spread of the solder paste on the electrodes, a step-like operation is performed with a stop time. You may go to

Further, in the present embodiment, the adhesive for temporarily fixing the electric circuit component was not used when the electric circuit component was placed on the circuit board, but it may be used if it causes a position shift when the electric circuit component is placed. Good. The composition of the solder paste solder is S
Although a spherical solder of u25%, Pb36%, Ag2% of φ25 to 45 μm was used, even if the bismuth-based low melting point is used,
It may be indium-based, and the shape of the solder contained may be indefinite or a mixture of spherical and indefinite because it increases the adhesion to the electrodes of the electric circuit component.

In the second embodiment, since the shape of the concave portion 1 is formed as a curved surface, the releasability and transferability are improved, and the solder paste is less likely to remain in the concave portion after the transfer. The effect of not causing defects such as balls could be confirmed. Next, a third embodiment will be described with reference to the drawings. FIG. 12 and FIG. 13 are cross-sectional views of main parts according to the third embodiment. In both drawings, the same reference numerals are given to the components already described in the description of the first embodiment and the second embodiment, and different. Regarding the part, the shape of the concave portion 1 of the solder paste transfer member 2 is different. That is, as shown in FIG. 12, the shape of the recess 1 of the transfer member 2 is such that the opening top surface 18 is a square of 0.5 mm on a side, the opening bottom surface 19 is a square of 0.2 mm on a side, and the depth is 0.1. Within the range of up to 0.3 mm, the size is reduced stepwise as it approaches the opening bottom surface 19 from the opening top surface 18.

Using the solder paste transfer member 2 formed as described above, the bare chip IC of the electric circuit component 5 having the solder paste 3 transferred to the electrode portion is formed into a ceramic circuit board shape as shown in FIG. It was positioned, fixed and placed by the same method as described above. As the solder paste 3, the product name SQ-2030SZH-1 manufactured by Tamura Corporation was used. In this embodiment, the ceramic substrate is used as the circuit substrate, but the present invention is not limited to this, and a silicon substrate or a glass substrate may be used.

As described above in detail, when soldering the electric circuit component to the circuit board, the solder paste filled in the concave portion having a predetermined shape corresponding to after each electrode of the electric circuit component is electrically applied. The capacitance of the recess is directly transferred onto the individual electrodes of the circuit component, and the solder paste can be supplied to the electrodes in a fixed amount. The supply amount can be controlled by changing the size of the recess.
Furthermore, by using the water-repellent / oil-repellent material on the surface of the solder paste transfer member or the concave portion of the solder paste transfer member, the solder paste and the water-repellent / oil-repellent material can be easily peeled off, and the quantitative supply effect can be obtained. Becomes noticeable.

These effects become more prominent in the soldering of electric circuit parts having a narrow pitch and a large number of pins, and solder bridges, solder balls, and unsolder are less likely to occur.
High quality soldering is possible. When large-pitch parts and narrow-pitch multi-pin parts are mixed, the large-pitch parts are printed with solder paste by the conventional method, and then the narrow-pitch multi-pin parts with solder paste transferred to the electrodes are placed and reflowed. This effect becomes remarkable by the method of. Also, by placing the surface of the solder paste transferred in the electrode part of the electric circuit component in contact with the electrode part of the circuit board, the solder paste is heated and melted, and soldering reduces solder bridges and solder balls. The effect becomes.

Further, the electric circuit component can be placed on either one or the other surface of the circuit board, and even if the electric circuit component is soldered, it can be easily soldered. The degree of freedom in the design and process of the circuit board is increased, which in turn improves the yield and reduces the cost.

[0045]

As described above, according to the present invention, not only large-pitch soldering can be performed but also narrow-pitch soldering and a large number of pins can be coped with, and the degree of freedom in the design of the circuit board and the degree of freedom in the process can be increased. It is possible to provide a soldering method that can increase

[Brief description of drawings]

FIG. 1 is a schematic external perspective view of a step of filling a solder paste according to a first embodiment.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a schematic cross-sectional view after aligning an electric circuit component with a solder paste transfer member.

FIG. 4 is a schematic cross-sectional view showing a state where an electrode of an electric circuit component and a solder paste in a recess are in contact with each other.

FIG. 5 is a schematic external perspective view showing a state in which the electric circuit component and the solder paste transfer member are separated from each other and the solder paste is transferred onto the electrodes.

FIG. 6 is a schematic cross-sectional view showing a state in which the solder paste transfer member is separated from the electric circuit component and the solder paste is transferred onto the electrodes.

FIG. 7 is a schematic cross-sectional view showing a state in which an electric circuit component 5 is aligned with an electrode on a circuit board.

FIG. 8 is a schematic sectional view in which an electric circuit component having a solder paste is placed on an electrode of a circuit board.

FIG. 9 is a schematic external perspective view of a second embodiment.

10 is a cross-sectional view taken along the line XX of FIG.

FIG. 11 is a schematic cross-sectional view showing a state where an electric circuit component is placed on a substrate.

FIG. 12 is a schematic sectional view of a third embodiment.

FIG. 13 is a schematic sectional view of a third embodiment.

FIG. 14 is a schematic cross-sectional view of a state where the electric circuit component of the third embodiment is placed on the substrate.

FIG. 15 is a schematic cross-sectional view of a conventional screen printing method.

FIG. 16 is a plan view of a defect example by the precoat method.

FIG. 17 is an external side view of the robot soldering method.

FIG. 18 is an external view of a defect example by the robot soldering method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 recessed part, 2 solder paste transfer member, 3 solder paste, 4 squeegee, 5 electric circuit component, 6 electric circuit component electrode, 7 adsorption holder, 8 circuit board, 9 circuit board electrode, 11 coating layer (coating layer) ), 12 squeegee skirt, 16 solder, 17 groove, 18 upper surface of recess opening, 19 lower surface of recess, and 20 alignment mark.

Claims (7)

[Claims] 1. A soldering method for soldering an electrode part of an electric circuit component and an electrode part of a circuit board, wherein a solder paste transfer member having a recess formed corresponding to the electrode part of the circuit board. With respect to the filling step of supplying a solder paste to fill the solder paste in the recess, by contacting the electrode of the electric circuit component with the filled solder paste, the solder paste in the recess A transfer step of transferring to the electrode portion of the electric circuit component, a placing step of placing the electrode portion of the electric circuit component having the transferred solder paste on the electrode portion of the circuit board, and heating and melting the solder paste. And a melting step of soldering the electrode portion of the electric circuit component and the electrode portion of the circuit board. 2. The soldering method according to claim 1, wherein a water-repellent treatment layer is further provided on the recess. 3. The soldering method according to claim 1, wherein the solder paste on the electrode portion of the electric circuit component is transferred to the opposite side of the circuit board that contacts the electrode portion. 4. A first electrode portion and a second electrode portion of a QFP electric circuit component.
In a soldering method of soldering an electrode portion and an electrode portion of a circuit board, a concave portion formed corresponding to the first electrode portion and the second electrode portion arranged in parallel on the circuit board is provided. A step of supplying a solder paste to the solder paste transfer member to fill the recess with the solder paste, and bringing the first electrode of the QFP electric circuit component into contact with the filled solder paste Thus, a transfer step of transferring the solder paste in the recess to the electrode portion of the electric circuit component, and after rotating the QFP electric circuit component by about 90 degrees, the second electrode to the filled solder paste. A transfer step of transferring the solder paste in the concave portion to the electrode portion of the electric circuit component by bringing them into contact with each other; and a QFP having the transferred solder paste. A placing step of placing the electrode portion of the electric circuit component on the electrode portion of the circuit board, and soldering the electrode portions of the QFP electric circuit component and the electrode portion of the circuit board by heating and melting the solder paste. A soldering method comprising: a melting step to be performed. 5. The soldering method according to claim 4, wherein the solder paste on each electrode portion of the QFP electric circuit component is transferred to the opposite side of the circuit board, which is in contact with the electrode portion. 6. The soldering method according to claim 4, wherein the recess is formed in a substantially hemispherical shape. 7. The soldering method according to claim 4, wherein the recess is formed in a step shape.