WO2002026007A1

WO2002026007A1 - Flux applying method and device, flow soldering method and device and electronic circuit board

Info

Publication number: WO2002026007A1
Application number: PCT/JP2001/008228
Authority: WO
Inventors: Yasuji Kawashima; Kenichiro Suetsugu; Shunji Hibino; Hiroaki Takano; Tatsuo Okuji; Shoshi Kabashima; Yukio Maeda; Mikiya Nakata
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2000-09-25
Filing date: 2001-09-21
Publication date: 2002-03-28
Also published as: JP2002100858A

Abstract

A flux applying method in a flow soldering process, capable of reducing a process defect to be caused by the deposition, as a foreign matter, of flux (3) residual spread on a board (1), on a conveying member in a post-process of flow soldering. A flux applying method for supplying flux (3) from under the board (1) by a flux supply means for application on the bottom surface (11) of the board, wherein, while the board (1) is being conveyed, flux (3) is supplied to the bottom surface (11) of the board from the flux supply means with each of a pair of edges of the bottom surface (11), along the conveying direction of the board (1), being covered with a pair of covers (8a, 8b) respectively located directly under the edges when the board (1) is positioned above the flux supply means, thereby supplying flux to those portions of the bottom surface (11) of the board excluding the pair of edges.

Description

, Coating method and apparatus,

Method and apparatus for soldering and electronic circuit board

The present invention relates to a method for applying a bright flux in flow soldering for mounting a component, for example, an electronic component on a substrate using a solder material, and an apparatus therefor. Further, the present invention provides a method and an apparatus using such a flux coating method and apparatus, respectively.

The present invention relates to a flow soldering method and an electronic circuit board manufactured by the flow soldering method. Background art

Conventionally, in the manufacture of electronic circuit boards, a flow soldering process using a solder jet has been known as one method of joining electronic components and the like to the board. This flow soldering process typically involves applying a flux to the board, a pre-heating step to pre-heat the board, and contacting the board with a jet of solder material to supply the solder material to the board. Includes solder material supply steps to be performed. This flux application step removes an oxide film (natural oxide film) unavoidably formed on a land formed on the substrate (that is, a portion to which the solder material is to be supplied) and removes the solder material on the land surface. This is done for the purpose of improving the wetting and spreading, and the flux usually contains an active ingredient such as rosin (resin component) and a solvent such as isopropyl alcohol. As a flux applying method for performing such a flux applying step, there are known a foaming method in which a foamy flux is brought into contact with a substrate, and a spraying method in which a mist-like flux is sprayed on the substrate.

Hereinafter, a conventional flow soldering process using a foam type flux application method will be described with reference to the drawings. Figure 7 shows the internal appearance of a conventional flow soldering device that uses a foam type flux application method when viewed from the side. FIG. Fig. 8 (a) illustrates how the flux is applied to the substrate located in the cross section along the line X-X in Fig. 7, and Fig. 8 (b) shows the state shown in Fig. 8 (a). It is a typical top view of the part of a board | substrate.

First, a printed circuit board on which electronic components such as through-hole insertion components (ie, components in which a part of the components are inserted into the through-holes (eg, discrete components or lead components) by a known method) are appropriately arranged in predetermined positions. The substrate 71 is supplied from the inlet 51 to the flow soldering device 50 shown in Fig. 7. The substrate 71 is provided inside the device 50 (along a transfer line shown by a dotted line in Fig. 7). The substrate 71 is mechanically transported at a substantially constant speed in the direction of the arrow 52. The substrate 71 is transported in more detail, as shown in FIGS. 8 (a) and 8 (b). This is carried out by mechanically moving the row-shaped transport claws 72 a and 72 b held by the section (or side) in the transport direction indicated by arrow 52. Here, the transport claws 7 2a and 7 2b is connected to chains 7 4a and 7 4b, respectively, as shown in Fig. 8 (a). Around the conveyor frames 75a and 75b extending from the inlet 51 to the outlet 53 (Fig. 7), respectively, in a plane parallel to the main surface of the substrate 71. When the substrate 71 conveyed in this way reaches above the foaming fluxer 54, it is foamed by the foaming device 55, rises inside the guide 56, and overflows outside the guide 56. The flux 73 is applied to the lower surface of the substrate 71 in contact with the lower surface of the substrate 71. The flux 73 overflowing from the guide 56 is generally a bubble having a diameter of about 1 to 2 mm. As shown in FIGS. 8 (a) and (b), the guide 56 has a width a longer than the width W of the substrate 71 and an opening (FIG. 8 (b)) having an appropriate length b. ), And the bubble-like flux 73 overflows from the opening, so that the lower surface of the substrate 71 Except for the area covered and held by the transport claws 72 a and 72 b. The flux 73 is applied to the area.

The substrate 71 to which the flux has been applied as described above is then heated by a pre-heater 57 such as a far-infrared heater while being transported (see FIG. 7). This heating step is called a pre-heating step. Of the flux 73 applied to the substrate 71 in the above flux application step, unnecessary solvent components are removed by degassing, and only the activator component is removed from the substrate 71. , And Prior to the supply of the solder material to the substrate 71, the substrate 71 is preheated to reduce the thermal shock to the substrate 71 caused when the molten solder material comes into contact with the substrate 71. It is.

Subsequently, the substrate 71 comes into contact with the primary jets 58 and the secondary jets 59 made of the solder material previously melted by heating on the lower surface side of the substrate 71, and the solder material is supplied to the substrate. . At this time, the solder material is applied between the land portion forming the inner wall of the through hole formed in the substrate and the lead of the through hole insertion component inserted into the through hole from the upper surface side of the substrate. The annular space gets wet from the bottom side of the substrate by capillary action. Thereafter, the solder material supplied to and adhered to the substrate 71 is solidified by a decrease in temperature to form a joint made of the solder material, a so-called “fillet”. In this solder material supply step (or flow soldering step), the primary jet flows through the surface of the land (and the lead of the electronic component) formed over the wall of the through hole by sufficiently wetting the surface with the solder material. This is for supplying solder material to the holes, and the secondary jet is not desirable because the solder material remains between the lands and solidifies to form a bridge (this bridge causes an electric circuit short circuit). In order to prevent the formation of horn-like protrusions, the excess solder material attached to the lower surface area of the substrate covered with the solder resist is removed, and the shape of the fillet is adjusted. The substrate 71 thus obtained is then taken out of the outlet 53.

As another example, a conventional flow soldering process using a spray-type flux application method will be described with reference to the drawings. FIG. 9 is a schematic cross-sectional view of a conventional flow soldering apparatus using a spray type flux application method. FIG. 10 (a) is a diagram for explaining how a flat plate is applied to a substrate located at a cross section along the line Y--Y of FIG. 9, and FIG. 10 (b) is a diagram illustrating that FIG. FIG. 3 is a partial top view of the substrate shown in a).

As shown in FIG. 9, a conventional flow soldering apparatus 60 using a spray type flux application method is composed of a spray fluxer 60a, which is a spray type flux application apparatus, and a flow soldering apparatus main body 60b. And power. In this device 60, the flux application step is performed in a spray fluxer 60a, and then the flux application step is performed. The reheating step and the solder material supply step are sequentially performed in the apparatus main body 60b. The description of the same components as those of the conventional flow soldering apparatus and method using the foaming type flux application method will be omitted below.

In this apparatus 60, first, the substrate 71 as described above is spray-fluxed.

Supplied to 60a from inlet 61. Substrate 71 moves the interior of spray fluxer 60a (along the transport line shown by the dotted line in FIG. 9) at a substantially constant speed in the direction of arrow 62 in the same manner as above. Transport claws 7 2a and 7 2b (Fig. 10 (a) and

(see (b)). When the substrate 71 conveyed in this way reaches above the nozzle 63, the nozzles 63 are moved in a plane perpendicular to the direction of conveyance of the substrate 71 (ie, the direction of the arrow 62) (ie, , The direction perpendicular to the plane of FIG. 9, and the flux while reciprocating (in the direction of arrows 76 in FIGS. 10 (a) and (b)).

By injecting 73 together with air, flux 73 is applied to the lower surface of substrate 71. The nozzle 63 generally has a circular injection port, and as shown in FIG. 10 (a), the flux 73 injected from the nozzle 63 is microscopically a droplet, and as a whole, In this case, the injection port of the nozzle 63 is the upper bottom (or the top), and the circular area of the diameter m (see FIG. 10 (b)) on the lower surface of the substrate 71 is the lower bottom. (Or substantially conical). The substrate 71 is transported in the direction indicated by the arrow 62, and at the same time, the nozzle 63 force is applied at a speed corresponding to the transport speed of the substrate 71 over a distance corresponding to the width W of the substrate 71, in the direction indicated by the arrow 176. Reciprocate. As a result, as shown in FIG. 10 (b), the circular area composed of the flux 73 simultaneously adhering to the substrate 71 crosses the lower surface of the substrate 71 obliquely to the transport direction of the substrate 71. Then, the flux 73 is applied to the entire lower surface of the substrate 71. Further, since the solvent contained in the flux 73 is easily volatilized by spraying, from the viewpoint of safety, in the spray fluxer 60a, an exhaust duct (see FIG. (Not shown) to suck and discharge the solvent that evaporates together with the atmospheric gas. The substrate 71 to which the flux has been applied as described above is then mechanically transferred from the spray fluxer 60a to the apparatus main body 60b at a position 64 shown in FIG. The substrate 71 is also mounted on the main body 60b of the main body 60b in the same manner as described above. Flow in the direction of arrow 65 (along the transport line shown by the dotted line in FIG. 9) while mechanically transporting at a substantially constant speed while using the above-mentioned foaming flux application method. In the same manner as in the above example, the calorie heat is generated by the pre-heater 66, and then the solder material is supplied from the lower surface of the substrate 71 in contact with the solder jets 67 and 68, and then is taken out from the outlet 69. It is.

As described above, an electronic circuit board in which electronic components are soldered to a substrate by a flow soldering process using a foam type or spray type flux application method is manufactured.

However, in the flux application step of the conventional flow soldering process as described above, in any of the flux application methods of the foaming type and the spray type, the substrate between the row-shaped transport claws is formed. There is a problem that the flux is applied to the edge, which is one of the causes of a process failure in a post-process of the flow soldering process.

In the conventional flux coating method, this is applied to all areas of the lower surface of the substrate except for the area covered with the carrier claws 72a and 72b, more specifically, to one end (or To the edge located in the gap between the row-shaped transport claws 72 a that sandwich and hold the other end of the row. This is due to the application of blood (see FIGS. 8 (a) and (b) and FIGS. 10 (a) and (b)). In the post-process of the flow soldering process, for example, in the inspection process, a belt or a chain is usually used as a transport member, and a pair of edges along the transport direction on the lower surface of the substrate (in other words, transport The left and right edges of the lower surface of the substrate are transported while supporting from below. When the flux is applied to the edge of the board (more specifically, the edge located in the gap between the transport claws) in the flux application step of the flow soldering process, the solvent component of the flux eventually vaporizes and the solvent is evaporated. The active component of the flux, such as rosin (resin component), remains in powder form on the substrate due to the evaporation of the gas. For example, rosin alone is a sticky solid at normal temperature and pressure. Therefore, the residue may be peeled off from the substrate in the above-described post-process and adhere to the conveying member in the post-process as a foreign substance. Such adhesion of foreign matter to the transport member may cause a process defect such as a failure of the transport member. There is a problem that can be. Disclosure of the invention

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a flux coating method in a flow soldering process for mounting an electronic component on a substrate using a solder material. A method capable of reducing the occurrence of process failures caused by the residue of the flux applied to the substrate adhering to the conveying member as a foreign substance in the post-process of the flow soldering process, and using the flux application method. It is an object of the present invention to provide a flow soldering method, an apparatus for performing the method, and an electronic circuit board manufactured by the flow soldering method.

In one aspect of the present invention, the flux is supplied to the lower part of the substrate by a flux supply means (or a unit or a device, for example, a fluxer) used in a flow soldering process of mounting an electronic component on a substrate using a solder material. Is a method of applying the flux supplied from the substrate to the lower surface of the substrate, wherein when the substrate is transported while the substrate is positioned above the flux supply means, a pair of the lower surface of the substrate along the transport direction of the substrate. Flux is supplied from the flux supply means to the lower surface of the substrate while the respective edges are covered with a pair of covers located immediately below the lower edge of the substrate, whereby the lower surface of the substrate excluding the pair of edges is removed. The method is characterized by applying a flux to the surface.

In this specification, the “edge” of the substrate refers to a peripheral region on the main surface of the substrate, and “a pair of 緣 portions on the lower surface of the substrate along the substrate transfer direction” Here, among the edges of the lower surface of the substrate, the portions located on the left and right sides of the substrate in the transport direction of the substrate are referred to (hereinafter, this is also simply referred to as “a pair of edges”). The term “directly below” a pair of edges on the lower surface of the substrate means that the cover covers the pair of edges and functions to substantially prevent the application of flux to the edges. Any position may be used as long as possible, and the cover may be in contact with the lower surface of the substrate, or a gap, preferably a slight gap, may be provided between the cover and the lower surface of the substrate.

According to the method of the present invention, a flux is applied to the lower surface of the substrate excluding a pair of edges along the substrate transport direction, and a pair of edges covered with a pair of covers is provided. No flux is applied to it, so the active ingredient of the flux is on one pair of edges

(Such as rosin) does not remain. Therefore, in a later step of the flow soldering process, when the substrate makes mechanical contact with a conveying member such as a belt in the area of the pair of edges, residual flux remains on the pair of edges. Since no object is attached, it is possible to avoid the residue of the frustum from adhering to such a conveying member, and it is possible to reduce the occurrence of process defects caused by this.

In a preferred embodiment, each of the pair of covers is an angle plate-shaped long member having an L-shaped cross-sectional shape defined by two sides, and the substrate is positioned above the flux supply means. In addition, one side of the L-shaped cross section defines the boundary between each pair of edges and the bottom surface of the board excluding the pair of edges at its ends, The other side of the L-shaped cross section abuts each edge, and is disposed below the edge. Thus, each cover abuts the edge so as to define a boundary between each edge and the bottom surface of the board excluding the pair of edges (ie, one pair of covers contacts the bottom surface of the board). On the lower surface of the board, the area covered by a pair of covers is `` a pair of edges '', and the area not covered by a cover is `` the lower surface of the board excluding a pair of edges ''. A boundary is defined between each of the pair of 緣 portions and the lower surface of the substrate excluding the pair of edges), and to isolate the pair of edges from the area where the flux is supplied Is preferred. In this way, by contacting the cover with the lower surface of the substrate, it is possible to ensure that the flats are not applied to a pair of the 緣 parts, and that the area where the flatus is applied and the area where the flux is not applied are provided. Can be clearly distinguished. However, the present invention is not limited to this, and a gap may be provided between the pair of covers and the lower surface of the substrate as long as the flux is not substantially applied to the pair of edges. Also, the cross-sectional shape of the cover is not limited to the above-described L-shape, but may be, for example, a T-shape in which one end of one side is joined inside the end of the other side, or a curved contour. May have any suitable shape, such as those having Further, even in the case of an L-shaped cross-sectional shape, the angle between the two sides does not need to be 90 degrees, and may be any other appropriate angle.

In a further preferred aspect, each of the pair of covers has an inclined portion that transitionally connects to an end of the one side at a portion that first contacts the substrate, and the substrate is When the substrate is transported upward from the flux supply means, the front edge of the lower surface of the substrate comes into contact with the inclined portion, and as the substrate is further transported upward from the flux supply means, the lower surface of the substrate is exposed. Pushes down the cover while sliding along the oblique portion, so that when the substrate is located above the flux supply means, the one side abuts the edge at its end. By providing such an inclined portion (or a tapered portion) on the cover, the cover can be moved at one end by using the movement of the cover itself conveyed above the flux supply means. The force bar can be moved to abut the lower surface. For this cover, a member having at least a part of which has elasticity can be used, and for example, a cover utilizing a panel panel can be used. However, the present invention is not limited to this, and the cover may be moved by other mechanical means (or a device), or may be fixed without being moved.

According to another aspect of the present invention, a flux is supplied from below the substrate by a flux supply unit and applied to a lower surface of the substrate, which is used in a flow soldering process of mounting an electronic component on the substrate using a solder material. A flux applying device: a transporting means (or device) for transporting the substrate; a flux supplying means (or unit or device) for supplying the flux from below the substrate; and when the substrate is positioned above the flux supplying means. A pair of covers, which are located directly below a pair of edges on the lower surface of the substrate along the direction of transport of the substrate and cover each edge, respectively. An apparatus for applying a flux is provided.

In a preferred embodiment, each of the pair of covers is an angle plate-shaped long member having an L-shaped cross-sectional shape defined by two sides, and the substrate is positioned above the flux supply means. One side of each L-shaped cross-section defines, at its end (or end face), the boundary between each of the pair of edges and the lower surface of the substrate excluding the pair of edges As described above, the other side of the L-shaped cross section is disposed below the edge in contact with each edge of the lower surface of the substrate.

In a further preferred aspect, each of the pair of covers has an inclined portion that transitionally connects to an end of the one side at a portion that first contacts the substrate, and the substrate is When it is not above the flux supply means, no external force is applied to the cover, and the end of the one side is located above the surface through which the lower surface of the substrate should pass, and the force is applied to the inclined portion. When the lower surface of the substrate is positioned intersecting with the surface to be passed so as to make initial contact with the substrate conveyed above the supply means, and the substrate is above the flux supply means, the lower surface of the substrate However, by applying a pressing force to the one side in contact with the cover, the cover is pushed down while being in contact with the edge at the end of the one side.

Such a flux coating apparatus of the present invention is suitably used for performing the above-described flux coating method of the present invention, and can obtain the same effects as the flux coating method of the present invention.

In a preferred embodiment of the flux coating method and the flux coating apparatus of the present invention, each of the pair of edges has a width of 2 to 15 mm, and more preferably a width of about 5 mm. . On the edge having such a width, there is usually no electronic component arranged, and there is no need to apply a flux. In addition, since the width of such a part is generally larger than the width (width from the edge of the substrate) that can mechanically contact the conveying member in the post-process of the flow soldering process, Adhesion of flux residue to the conveying member can be avoided.

The flux supplying means in the flux applying method and apparatus of the present invention includes a foaming type flux supplying means (for example, a foaming fluxer) for bringing a foamy flux into contact with a substrate and a spraying type flux supplying a mist-like flux to the substrate. Means (for example, spray fluxer) may be used, or a combination of a foaming type and a spray type flux application method may be used. For example, the flux may be applied to the substrate by spraying and then applied by foaming, or vice versa.

According to another aspect of the present invention, there is provided a flow soldering method (or process) including a flux applying method and a flux applying apparatus according to the present invention, and a tip-to-solder apparatus, respectively. The effect can be obtained.

According to still another aspect of the present invention, there is provided an electronic circuit board having electronic components mounted on the board by a flow soldering process using a solder material, wherein the board is carried. An electronic circuit board having a flux applied to the lower surface of the substrate except for a pair of edges on the lower surface of the substrate along the feeding direction, preferably a pair of edges each having a width of 2 to 15 mm. Provided.

In the present invention, the term “flux” is applied for the purpose of removing oxides from the surface of a metal (for example, a land) to which a solder material is to be supplied and improving the wettability of the solder material on the surface. And contains a solvent for removing the acid component and a solvent for facilitating the handling of the active component. Active ingredient, for example about 3 to 20 weight ^_0/0, the solvent may be about 80 to 97 wt%. Such active components include rosin and organic acids (for example, diphenyl diadic acid hydrobromide), and the ionic lj includes isopropyl alcohol. The flatus may also contain, in addition to these active ingredients and solvents, trace amounts of other ingredients such as, for example, matting agents. For example, a commercially available flux can be used.

Solder materials that can be used in the present invention include, for example, Sn-Pb-based materials, Sn-Cu-based materials, Sn_Ag-Cu-based materials, Sn-Ag-based materials, Sn-Ag-Bi-based materials, and S-based materials. n-Ag-Bi-Cu material and other solder materials. Considering the impact on the environment, Sn-Pb-based materials, Sn-Cu-based materials, Sn-Ag-Cu-based materials, 311-§-based materials, Sn-Ag-Bi Pb-free solder materials such as Sn-Ag-Bi-Cu-based materials are preferred.

As the substrate that can be used in the present invention, for example, a substrate made of a paper phenol-based material, a glass epoxy-based material, a polyimide film-based material, a ceramic-based material, or the like can be used. Electronic components bonded to the board include imported components (eg, semiconductors, capacitors, resistors, coils, connectors, etc.) and surface-mounted components (eg, semiconductors, capacitors, resistors, coils, etc.) placed on the back of the Z or board. ). However, these are merely examples, and the present invention is not limited to these. The present invention includes the following embodiments 1 to 16.

(Aspect 1) Flow soldering for mounting electronic components on a board using a solder material This is a method of applying a flux from below the substrate by a flux supply unit and applying the flux to the lower surface of the substrate, which is used in the process, wherein the substrate is transported while the substrate is positioned above the flux supply unit. Flux is supplied from the flux supply means to the lower surface of the substrate while a pair of covers respectively located directly below a pair of edges on the lower surface of the substrate along the transport direction of the substrate cover the lower surface of the substrate. Applying a flux to the lower surface of the substrate excluding a pair of edges.

(Aspect 2) The method according to Aspect 1, wherein each of the pair of edges has a width of 2 to 15 mm.

(Aspect 3) Each of the pair of covers is an angle plate-shaped long member having an L-shaped cross-sectional shape defined by two sides, and when the substrate is located above the flux supply means, One side of the L-shaped section is at its end, the edge

Abutting against each edge of the lower surface of the board to define a boundary between each of the pair of edges (more specifically, each of the pair of edges) and the lower surface of the board excluding the pair of edges; 3. The method according to embodiment 1 or 2, wherein the other side is located below the edge.

(Aspect 4) Each of the pair of covers has an inclined portion that transitionally connects to the end of the one side at a portion that first comes in contact with the substrate, and the substrate is located above the flux supply means. When the substrate is transported toward the upper surface, the front edge of the lower surface of the substrate comes into contact with the inclined portion, and as the substrate is further transported above the flux supply means, the lower surface of the substrate slides along the inclined portion to cover the substrate. 4. The method according to claim 3, wherein said one side abuts the edge at its end when the substrate is positioned above the flux supply means.

(Aspect 5) The method according to any one of aspects 1 to 4, wherein the flux supplying means is a foaming type flux supplying means for bringing a foamy flux into contact with the substrate.

(Aspect 6) The method according to any one of aspects 1 to 4, wherein the flux supply means is a spray type flux supply means for spraying a mist-like flux onto the substrate.

(Embodiment 7) A flux application device for supplying a flux from below a substrate by a flux supply means and applying the flux to a lower surface of the substrate, which is used in a flow soldering process of mounting an electronic component on a substrate using a solder material:

Transport means for transporting the substrate, A flux supply means for supplying a flux from below the substrate, and a flux supply means for positioning the substrate directly above a pair of edges on a lower surface of the substrate along the substrate transport direction when the substrate is located above the flux supply means; And a pair of covers covering the edges, wherein the flux is applied to the lower surface of the substrate excluding the pair of edges.

(Aspect 8) Aspect 7 \ Z, wherein each of the pair of edges has a width of 2 to 15 mm.

(Aspect 9) Each of the pair of covers is an angle plate-shaped long member having an L-shaped cross-sectional shape defined by two sides, and when the substrate is located above the flux supply means, One side of the L-shaped section is at its end, the edge

Abutting against each edge of the lower surface of the board to define a boundary between each of the pair of edges (more specifically, each of the pair of edges) and the lower surface of the board excluding the pair of edges; Apparatus according to embodiment 7 or 8, wherein the other side is located below the edge.

(Aspect 10) Each of the pair of covers has an inclined portion that is transitionally connected to the end of the one side at a portion that first comes in contact with the substrate, and the substrate is located above the flux supply means. When no external force is applied to the cover, the end of the one side is located above the surface through which the lower surface of the substrate should pass, and the force and the inclined portion are located above the flux supply means. When the lower surface of the substrate is positioned intersecting with the surface to be passed so that the substrate comes into contact with the substrate first, and the substrate is above the flux supply means, the lower surface of the substrate is Aspect 9 is described, wherein the cover is pushed down while being in contact with the edge at the end of one side by applying a pressing force to the one side in contact.

1) The apparatus according to any one of aspects 7 to 7, wherein the flux supplying means is a foaming type flux supplying means for bringing a foamy flux into contact with the substrate.

(Aspect 12) The apparatus according to any one of aspects 7 to 10, wherein the flux supply means is a spray-type flux supply means for spraying a mist-like flux onto the substrate.

(Embodiment 13) A soldering method including the flux applying method according to any one of Embodiments 1 to 6.

(Aspect 14) A flux including the flux coating device according to any of Aspects 7 to 12. Low soldering equipment.

(Aspect 15) An electronic circuit board having electronic components mounted on the board by a flow soldering process using a solder material, and excluding a pair of edges on a lower surface of the board along the board conveying direction. Electronic circuit board with flux applied to the underside of the board.

(Aspect 16) Aspect 1 wherein each of a pair of edges has a width of 2 to 5 mm.

The electronic circuit board according to 5. BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1 (a) and 1 (b) illustrate a flux application method according to one embodiment of the present invention. The inside of a flow soldering apparatus in a direction perpendicular to a substrate transport direction above a flux supply means. FIG. 1 (a) is a schematic cross-sectional view, in which FIG. 1 (a) shows a state where there is no substrate above the flux supply means, and FIG. 1 (b) shows a state where there is a substrate above the flux supply means.

FIG. 2 is a schematic top view of a portion of the substrate shown in FIG. 1 (b).

FIGS. 3 (a) and 3 (b) are schematic enlarged perspective views of the interior of the flow soldering device shown in FIGS. 1 (a) and 1 (b), respectively.

FIG. 4 is a schematic perspective view of the substrate coated with flux according to the embodiment of FIG. 1 as viewed from the lower surface side.

FIGS. 5 (a) and 5 (b) show a flow soldering apparatus in a direction perpendicular to the direction in which a substrate is transported, above a flux supply means, illustrating a flux application method according to another embodiment of the present invention. 5 (a) shows a state where there is no substrate above the flux supply means, and FIG. 5 (b) shows a state where there is a substrate above the flux supply means. .

FIG. 6 is a schematic top view of the portion of the substrate shown in FIG. 5 (b).

FIG. 7 is a schematic cross-sectional schematic view of one conventional flow soldering apparatus.

Fig. 8 (a) is a diagram illustrating how the flux is applied to the substrate located in the cross section along the line X-X in Fig. 7, and Fig. 8 (b) FIG. 3 is a schematic top view of a part of the substrate shown.

FIG. 9 is a schematic cross-sectional schematic view of another conventional flow soldering apparatus. FIG. 10 (a) is a diagram for explaining how the flux is applied to the substrate located in the cross section along the line Y_Y of FIG. 9, and FIG. 10 (b) is a diagram illustrating the substrate shown in FIG. 10 (a). It is a typical top view of the part. BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1)

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. The present embodiment relates to a foam type flux applying method using a foaming fluxer as a flux supplying means, and a flux applying apparatus. The flux applying method and apparatus of the present embodiment relate to the flux applying step of the conventional flow soldering method and apparatus described with reference to FIGS. FIGS. 1 (a) and 1 (b) are views corresponding to FIG. 8 (a) referred to for describing the above-mentioned conventional flux coating method, and show a state in which there is no substrate above the flux supply means. And a certain state. FIG. 2 is a diagram corresponding to FIG. 8 (b) referred to for explaining the above-mentioned conventional flux coating method.

As partially shown in FIGS. 1 (a) and (b), the flux application device of the present embodiment was connected to chains 4a and 4b respectively rotating around conveyor frames 5a and 5b, respectively. It has conveying claws 2a and 2b, and a foaming fluxer including a guide 6 and a foaming device (not shown). The transport claws 2a and 2b are arranged so that the substrate 1 is sandwiched from above and below at both ends (or sides) of the substrate 1 in the transport direction 9 (that is, the direction perpendicular to the plane of the paper of FIGS. The foaming fluxer is a flux supplying means for supplying the flux 3 to the lower surface 11 of the substrate 1 located above the foaming fluxer. These members are the same as those described with reference to the conventional flow soldering apparatus described with reference to FIGS. 7 and 8, and a description thereof will be omitted.

Further, as shown in FIGS. 1 (a) and 1 (b), the flux application device of the present embodiment has a pair of mounting members 7a and 7b respectively attached to the conveyor frames 5a and 5b. It has covers 8a and 8b and differs from the conventional one in this point. These covers 8a and 8b are transported by the transport claws 2a and 2b. On the surface perpendicular to the transport direction 9 of the substrate 1 to be transported (that is, the paper surface in FIGS. 1A and 1B), the substrate 1 is formed of an angle plate-shaped elongated member having an L-shaped cross section. The covers 8a and 8b pass through the center of the substrate, are perpendicular to the main surface of the substrate, and are arranged symmetrically with respect to a plane (not shown) parallel to the direction of transport of the substrate. Hereinafter, the power bar 8a will be described in detail, but the cover 8b has a similar configuration and function. The cover 8a has an L-shaped cross-sectional shape defined by two sides A and B, as shown in FIG. The sides A and B refer to a vertical portion and a horizontal portion of the cover 8a, respectively, and each have a plate-like shape having a predetermined thickness cross section. Sides A and B may be joined using separate elongated members (or plate members) of different or identical materials, or integrated using the same material, to provide an L-shaped cross section May be configured. A member obtained by bending a flat member to have an L-shaped cross section may be used. For the cover, a member having two sides such as a chevron or an angle material may be used, and when the angle between these two sides is 90 degrees, an L-shaped cross section is formed. The temperature is not limited, and may be less than 90 degrees or greater than 90 degrees, and may be appropriately selected by those skilled in the art.

As shown in FIG. 2, the cover 8a extends over a distance L longer than the length b of the opening of the guide 6 of the foaming fluxer, and when the substrate 1 is located above the opening of the guide 6, On the lower surface 11 of the substrate 1 having a width W, they are arranged so as to overlap each other by a width d to form an edge 11a. When the substrate 1 is located above the guide 6 of the foaming fluxer as the flux supply means, referring to FIG. 1 (b) and FIG. 4, one side A of the L-shaped cross section of the force bar 8a is At its end 10, between one edge 11 a of the lower surface 11 and a middle portion 11 c of the lower surface 11 excluding a pair of edges 11 a and 11 b. The other side B of the L-shaped cross section is arranged below and preferably spaced apart from the edge 11 a of the lower surface 11 of the substrate 1 so as to define the boundary. Is done. Here, a pair of edges 11 a and lib on the lower surface 11 of the substrate 1 along the transport direction 9 of the substrate 1 is preferably about 2 to 15 mm, more preferably about 5 mm in width d. However, in some cases, different widths may be appropriately selected.

Further, as shown in FIG. 3 (a), a portion of the cover 8 a that comes into contact with the substrate 1 first has an inclined portion (or a tapered portion) that transitionally connects with the end 10 of the side A of the L-shaped cross section. 1 0 ′ is provided, and the inclined portion is inclined in a cross section including the substrate transfer direction. Cover 8a force Open state where no external force is applied as shown in Fig. 1 (a) and external force due to base plate 1 fixed in the vertical direction by transport claws 2a and 2b as shown in Fig. 1 (b) It is preferable that at least a part of the covers 8a and Z or the attachment 7a have sufficient elasticity so that a transition can be made between the pressed state and the pressed state. For example, a panel panel or the like can be used for the cover 8a. The same applies to the cover 8b and the mounting fixture 7b.

More specifically, when there is no substrate 1 above the guide 6 of the foaming fluxer, which is a flux supply means, as shown in FIG. 1 (a), the cover 8a is in an open state receiving no external force, and The end 10 of the side A (vertical portion) of a is located above the surface through which the lower surface 11 of the substrate 1 should pass (the surface indicated by the dotted line in the figure, also referred to as the reference surface). The inclined portion 10 ′ (FIG. 3) intersects with the reference plane so as to make first contact with the substrate 1 conveyed toward above the guide 6. On the other hand, when the substrate 1 is above the guide 6, the cover 8a is in a pressed state under external force as shown in FIG. 1 (b), and the lower surface 11 of the substrate 1 is By applying a pressing force to the side A contacting with, the cover 8a is pressed down while being in contact with the edge of the lower surface 11 at the end 10 of the side A.

Hereinafter, a flux coating method using such a flux coating device will be described. First, as shown in Fig. 1 (a) and Fig. 3 (a), the board 1 is transported from above and below at both ends of the guide 6 above the opening of the guide 6 where no external force is applied to the covers 8a and 8b. The sheet is transported in the transport direction 9 while being held between the claws 2a and 2b. When the board 1 is conveyed above the opening of the guide 6, the front side of the board 1 comes into contact with the inclined portions 10 of the covers 8a and 8b first, and the board 1 As the substrate 1 is further transported upward, the lower surface 11 of the substrate 1 slides along the inclined portions 10 and pushes down the covers 8a and 8b. Then, the front edge of the substrate 1 passes through the inclined portion 10 ′, and as shown in FIGS. 1 (b) and 3 (b), ends 10 A of the sides A of the covers 8 a and 8 b. , The edge 10 of the side A comes into contact with the edge of the lower surface 11 of the substrate 1. Thereby, the covers 8a and 8b are connected between the edges 11a and 11b shown in FIG. 4 and the intermediate portion 11c of the lower surface of the substrate excluding the pair of edges. Edges 11a and 11b abut at end 10 so as to define the boundaries between them, and a pair of edges 11a and 11b are in contact with lower surface 11 of substrate 1. It is covered with abutting covers 8a and 8b to isolate it from the area where the flux is supplied. In this way, with the pair of edges 11a and 11b covered by the pair of covers 8a and 8b, respectively, the substrate 1 above the opening of the guide 6 When flux 3 is supplied to the lower surface 11, the flux 3 is applied to the middle portion 1 1 c of the lower surface of the substrate excluding the pair of edges 11 a and 11 b, and the pair of edges 11 a and No liberation is applied to lib.

Further, in order to cope with the fact that the width W of the board 1 varies depending on the type of the board, the other conveyor frame 5a is fixed, and the other conveyor frame 5b is fixed to the fixed conveyor frame in a direction perpendicular to the board transfer direction. 5 Slide in the direction that can maintain the parallel relationship with a (that is, in the direction indicated by the arrow in FIG. 1 (a) and to the left and right in the plane of FIGS. 1 (a) and (b)). It is preferable that the width between the transfer claws 2a and 2b for holding the slide can be adjusted. In this case, since the cover 8b is connected to the conveyor frame 5b by the attachment 7b as in the present embodiment, the cover 8b slides by the same distance as the conveyor frame 5b slides. Therefore, the width of the edge d can be maintained at a predetermined value only by appropriately setting the conveyor frame 5 b according to the width W of the substrate 1 without having to set the cover 8 individually. There are advantages.

When the flux is applied by using the flux applying method and the coating apparatus of the present embodiment as described above, the flats are not applied to the pair of edges of the substrate, so that the residual of the flatus is transported in the subsequent process. Adhering to the member is avoided, and the occurrence of process defects due to this can be reduced.

Note that the flux application device of the present embodiment can be integrated into the flow soldering device as in the conventional flow soldering device described with reference to FIGS. 7 and 8. It may be configured separately and independently outside the device body.

Further, in the present embodiment, a force bar having an L-shaped cross-sectional shape and a tapered portion is brought into contact with the lower surface of the substrate by utilizing elasticity of at least a part of the cover (or A pair of edges is separated from the flux supply unit, but the present invention is not limited to this, and when the substrate is located above the flux supply means, the pair of edges is separated along the transport direction of the substrate. It is easy for those skilled in the art that the modifications can be made to the extent that each edge can be covered with a pair of covers located immediately below a pair of edges on the lower surface of the substrate. Will be reminded. Specifically, the cross-sectional shape of the cover is changed to, for example, a T shape, the slope is curved, or the cover is mechanically moved up and down so as to contact the lower surface of the substrate. It is also possible. Even if the cover is not brought into contact with the lower surface of the substrate, a gap may be provided between the cover and the lower surface of the substrate such that the flats are not substantially applied to the pair of edges.

(Embodiment 2)

The present embodiment relates to a flow soldering method and apparatus including the flux application method and apparatus of Embodiment 1. In the flow soldering apparatus according to the present embodiment, the flux application apparatus described in detail in Embodiment 1 is integrated into the inside like the conventional flow soldering apparatus described with reference to FIG. It is composed. Any suitable device for supplying the preheater and the solder material in the form of a jet except for the flux coating device may be used, for example, as shown in FIG. Using such a flow soldering apparatus, a flux is applied in the same manner as in the first embodiment, and then subjected to a preheating (preheating) step and a solder material supply step in the same manner as in the conventional method described above. , Flow soldering process

(Method) is completed, and an electronic circuit board on which electronic components are mounted is obtained. In the obtained electronic circuit board, a flux is not applied to a pair of edges of the electronic circuit board, which is sent to a post process of the soldering process, for example, an inspection process. As described in the above, it is possible to reduce the occurrence of process defects due to the adhesion of the flux residue to the transport member in the post-process.

(Embodiment 3)

Next, another embodiment of the present effort will be described with reference to FIGS. In this embodiment, a flux using a spray fluxer as a flux supply means is used. The present invention relates to a play type flux applying method and a flux applying apparatus. The flux applying method and apparatus of the present embodiment relate to the flux applying step of the conventional flow soldering method and apparatus described with reference to FIGS. 9 and 10. FIGS. 5 (a) and 5 (b) correspond to FIGS. 10 (a) and 10 (a), respectively, which are referred to for explaining the above-mentioned conventional flux application method, and each of them has no substrate above the flux supply means. State and a state. FIG. 6 is a diagram corresponding to FIG. 10 (b) referred to for describing the above-mentioned conventional flash coating method. The flux applicator of the present embodiment partially shown in FIGS. 5A and 5B is the same as the flux applicator of the first embodiment, but instead of a foaming fluxer as a flux supply means, FIG. 10 and an exhaust duct (see FIG. 10) for sucking the ambient gas using the spray fluxer used for the soldering device in the same manner as the device shown in FIGS. 9 and 10. (Not shown) is provided above the substrate.

In this embodiment, except that the flux 3 is ejected from the nozzle 12 reciprocating in the direction of the arrow 13 and is supplied to the substrate 1, the substrate is formed in the same manner as in the first embodiment. Can be coated with a flux. Also in the present embodiment, as in the first embodiment, the flux 3 is applied to the lower surface 11 of the substrate 1 while the pair of edges of the substrate 1 is covered by the covers 8a and 8b. Flux 3 is applied to the middle part of the lower surface of the substrate except for the edge of the pair, and flux 3 is not applied to the edge of the pair. Thereby, also in the present embodiment, the same effect as in the first embodiment can be obtained.

Note that the flux coating device of the present embodiment can be separately and independently provided outside the flow soldering device main body, similarly to the conventional flow soldering device described with reference to FIGS. 9 and 10. However, it may be integrated into the flow soldering device. In the second embodiment, it is also possible to carry out the flow soldering by using the flux applying method and the apparatus of the first embodiment instead of the flux applying method and the apparatus of the first embodiment. Furthermore, the foam type flux applying method and apparatus of Embodiment 1 may be combined with the spray type flux applying method and apparatus of this embodiment. Industrial applicability

According to the present invention, there is provided a flux coating method used in a flow soldering process for mounting an electronic component on a substrate using a solder material, wherein the flatus residue applied to the substrate is used in the flow soldering process. Provided is a method capable of reducing the occurrence of a process failure caused by adhering to a conveying member as a foreign substance in a subsequent process, and an apparatus for performing the method. Further, according to the present invention, there is provided a flow soldering method using the flux applying method and an electronic circuit board manufactured by the flow soldering method, as well as an apparatus for performing the method. According to the present invention, a flux is applied to the lower surface of the substrate except for a pair of edges along the transport direction of the substrate, and a pair of edges covered with a pair of covers is provided on the lower surface of the substrate. Since the flux is not applied, it is possible to avoid the residue of the flux from adhering to the conveying member in the post-process of the flow soldering process, and to reduce the occurrence of process defects due to this. The present application is based on the Paris Convention and is based on the Paris Convention. The patent application of the patent application in the thirteenth country, entitled “Flux coating method, flow soldering method, device for these and electronic circuit board” Claim the priority of No. 90263 (filed on September 25, 2000). The contents of that application are incorporated herein by reference in their entirety.

Claims

The scope of the claims

1. A flux application method in which flux is supplied from below the substrate by a flux supply means and applied to the lower surface of the substrate, which is used in the flow soldering process of mounting electronic components on the substrate using a solder material. While the substrate was positioned above the flux supply means, each edge was covered with a pair of covers located directly below a pair of edges on the lower surface of the substrate along the substrate transport direction. In the state, the flux is supplied from the flux supply means to the lower surface of the substrate, whereby the flux is applied to the lower surface of the substrate except for a pair of the portions.

2. The method of claim 1, wherein each of the pair of edges has a width of 2 to 15 mm.

3. Each of the pair of covers is an angle plate-shaped long member having an L-shaped cross-sectional shape defined by two sides, and when the substrate is positioned above the flux supply means, the L-shape is formed. The lower surface of the substrate is such that one side of the cross-section defines at its ends the boundaries between each of the pair of edges and the lower surface of the substrate excluding the pair of edges. Claim: wherein the other side of the L-shaped cross-section is disposed below the edge in contact with each edge.

The method according to 1.

4. Each of the pair of covers has an inclined portion that transitionally connects to the end of the one side at a portion where the cover first comes in contact with the substrate, and the substrate is conveyed toward above the flux supply means. As the front edge of the lower surface of the substrate comes into contact with the inclined portion, and as the substrate is further transported above the flux supply means, the lower surface of the substrate slides down the inclined portion and pushes down the cover. 4. The method according to claim 3, wherein said one side abuts the edge at its end when the substrate is located above the flux supply means.

5. The method according to claim 1, wherein the flux supplying means is a foaming type flux supplying means for bringing a foamy flux into contact with the substrate.

6. The method according to claim 1, wherein the flux supply means is a spray-type flux supply means for spraying a mist-like flux onto the substrate.

7. Flow soldering process for mounting electronic components on a board using a solder material A flux application device for supplying a flux from below the substrate by a flux supply means and applying the flux to a lower surface of the substrate, wherein:

Transport means for transporting the substrate,

Flux supply means for supplying flux from below the substrate,

A pair of covers, which are located directly below a pair of edges on the lower surface of the substrate along the transport direction of the substrate and cover the edges, respectively, when the substrate is located above the flux supply means; Flux is applied to the lower surface of the substrate excluding the edge of the pair

8. The method of claim 7, wherein each of the pair of edges has a width of 2 to 15 mm.

9. Each of the pair of covers is an angle plate-shaped long member having an L-shaped cross-sectional shape defined by two sides, and when the substrate is located above the flux supply means, the L-shape is formed. The lower surface of the substrate is such that one side of the cross-section defines at its ends the boundaries between each of the pair of edges and the lower surface of the substrate excluding the pair of edges. 8. The device according to claim 7, wherein the abutment is on each edge, and the other side of the L-shaped cross section is located below the edge.

10.0.1 when each of the pair of covers has an inclined portion transitionally connected to the end of the one side at a portion where the cover first comes in contact with the substrate, and the substrate is not above the flux supply means. The end of the one side is located above the surface through which the lower surface of the substrate should pass, and the inclined portion faces upward of the flux supply means without external force being applied to the cover. When the lower surface of the substrate passes through the lower surface of the substrate so as to make first contact with the substrate to be conveyed, the lower surface of the substrate is located in contact with the surface when the substrate is above the flux supply means. The apparatus according to claim 9, wherein the cover is pushed down by applying a pressing force to one side while abutting the edge at the end of the one side.

11. The apparatus according to claim 7, wherein the flux supply means is a foaming type flux supply means for bringing foamy flux into contact with the substrate.

12. The apparatus according to claim 7, wherein the flux supply means is a spray-type flux supply means for spraying mist-like flux onto the substrate.

13. The method of applying the flux application method according to any one of claims 1 to 6. How to attach.

14. A flow soldering device including the flux coating device according to any one of claims 7 to 12.

15 5. An electronic circuit board on which electronic components are mounted on a board by a flow soldering process using a solder material, and a flux is applied to the lower face of the board except a pair of edges on the lower face of the board along the board transport direction. Electronic circuit board to which is applied.

16. The electronic circuit board according to claim 15, wherein each of the pair of edges has a width of 2 to 15 mm.