JP4477375B2 - Electronic circuit board manufacturing method - Google Patents

Description

  The present invention includes a step of closely attaching a printing stencil to a substrate, a step of filling each hole of the printing mask with a solder paste, a step of placing electronic components on the printing stencil, and melting the solder paste It is related with the manufacturing method of the electronic circuit board which performs the process to make.

  In recent years, electronic components such as semiconductor devices such as BGA (Ball Grid Array), LGA (Land Grid Array), and CSP (Chip Size Package) have an array of junction electrodes on the lower surface of the package. In such an electronic component (hereinafter referred to as a bottom surface electrode array type electronic component), unlike a QFP (Quad Flat Pack) in which a bonding electrode protrudes from the side surface of the package in a gull wing shape, There is no need to take up space. For this reason, the electronic circuit board can be miniaturized.

  However, in an electronic circuit board, as a result of a design change in a wiring pattern, an electronic component, etc., it may be necessary to perform a jumper process by connecting two electrodes with a conductive wire called a jumper wire. If the target area of the jumper process is a placement area for the electronic component of the bottom electrode array system, if the jumper wire is fixed there, a jumper wire is placed between the electrode of the electronic component and the electrode of the substrate. There is a possibility of causing conduction failure by interposing.

  On the other hand, the present applicant previously described in Japanese Patent Application Laid-Open No. H10-260260, after printing jumper wires using a stencil for solder paste printing, the electronic component is mounted on the substrate while the stencil is interposed between the electronic component and the substrate. An electronic circuit board manufacturing method fixed on top was proposed. In this electronic circuit board manufacturing method, as a stencil plate, in addition to a hole pattern corresponding to an electrode pattern of a substrate or an electronic component, a plate having a long hole for a jumper wire is used. Then, after solder paste is imprinted in the hole pattern or long hole of the stencil in close contact with the substrate, an electronic component is placed on the stencil, and then the solder is melted and solidified by heating. Then, via the solder in the hole pattern, each electrode on the lower surface of the electronic component is electrically connected to each electrode on the board, and a jumper wire for short-circuiting the two electrodes on the board with the solder filled in the long hole is provided. Can be formed. About this jumper wire, it can form so that each electrode of a board | substrate and an electronic component may be avoided by devising the position and shape of the long hole in a stencil. Therefore, it is possible to eliminate a situation in which a jumper wire is interposed between the electrode of the electronic component and the electrode of the substrate to cause conduction failure.

JP 2001-308513 A

  However, in addition to a plurality of electrodes corresponding to the electrode pattern of the electronic component, a wiring pattern for conducting these electrodes to various locations is formed in the mounting region of the electronic component on the substrate. In the electronic circuit board manufacturing method described in Patent Document 1, a jumper wire formed by a long hole in the stencil may cause a short circuit between the lines in the wiring pattern.

  This invention is made | formed in view of the above background, The place made into the objective is providing the following electronic circuit board manufacturing methods. That is, the jumper treatment is performed between the electrodes in the electronic component mounting region of the substrate while eliminating the conduction failure of both electrodes by interposing the jumper wire between the electrode of the substrate and the electrode of the electronic component, and An electronic circuit board manufacturing method capable of avoiding an unexpected short circuit of a wiring pattern of a board due to a jumper process.

In order to achieve the above object, the invention according to claim 1 is an adhesion step of closely attaching a printing stencil having a hole pattern corresponding to the electrode pattern to the substrate on which the electrode pattern is formed, and the substrate. A filling step of filling each hole of the printing stencil in close contact with the solder paste, a placing step of placing an electronic component having an electrode pattern formed on the lower surface on the printing stencil, A melting step in which the solder paste is heated to melt the solder grains in the solder paste, the melted solder is cured by cooling, and each electrode in the electrode pattern of the substrate and each electrode in the electrode pattern of the electronic component are In the electronic circuit board manufacturing method for manufacturing an electronic circuit board by performing a soldering process for soldering the printed circuit board, the printing stencil is made of an insulating material and has a circuit repair. Using a groove having a groove-like recess corresponding to the shape of the wiring for wiring and at least two holes formed in the groove-like recess, and between the two holes in the groove-like recess after the adhesion step. After carrying out a wire loading step of feeding an electric wire into the groove-shaped recess so as to be twisted, and a recess closing step of closing the groove-shaped recess after closing the wire with an adhesive tape and closing the opening , The filling step is performed.

  According to a second aspect of the present invention, in the electronic circuit board manufacturing method according to the first aspect, the electric wire having a surface plated with solder is used.

According to a third aspect of the present invention, there is provided an adhesion process in which a printing stencil having a hole pattern corresponding to the electrode pattern is adhered to the substrate on which the electrode pattern is formed, and the printing in which the substrate is adhered to the substrate. A filling step of filling each hole of the stencil with a solder paste, a placing step of placing an electronic component having an electrode pattern formed on the lower surface on the printing stencil, and heating the solder paste in each hole A melting step of melting the solder particles in the solder paste, and a curing step of soldering the melted solder by cooling to connect each electrode in the electrode pattern of the substrate to each electrode in the electrode pattern of the electronic component In the electronic circuit board manufacturing method for manufacturing the electronic circuit board, the printing stencil is made of an insulating material and corresponds to the shape of the circuit correction wiring. In addition, after the contact step, a covered electric wire whose surface is covered with an insulating material is put into the elongated hole so as to lie along the longitudinal direction of the elongated hole. The filling step is performed after an electric wire charging step and an oblong hole closing step in which the opening of the elongated hole into which the covered electric wire has been charged is closed with an adhesive tape are closed.

According to a fourth aspect of the present invention, in the electronic circuit board manufacturing method according to any one of the first to third aspects, the printing stencil is made of polyimide.

The invention according to claim 5 is the electronic circuit board manufacturing method according to any one of claims 1 to 4 , wherein the air-permeable pressure-sensitive adhesive tape exhibits air permeability between the adhesion step and the wire feeding step. A stencil fixing step of fixing the stencil to the substrate is performed, and after the curing step, a tape peeling step of peeling the breathable adhesive tape from the printing stencil is performed.

According to a sixth aspect of the present invention, in the method for manufacturing an electronic circuit board according to any one of the first to fifth aspects, the electric wire for soldering both ends of the electric wire or the covered electric wire to the electrodes of the substrate after the electric wire charging step, respectively. The filling step is performed after the soldering step.

In these inventions, an electronic circuit board is manufactured by the structure according to any one of claims 1 and 3 .
Their to, in the invention of manufacturing an electronic circuit board by the configuration of claim 1, one end portion of the wire were placed in a groove-like recess of the printing stencil, and an electrode formed on the substrate, the groove-shaped recess Connect through the hole. This connection may be made by filling the hole of the groove-shaped recess with a solder paste in the filling step and then melting and solidifying it, or by manual soldering. On the other hand, the other end portion of the electric wire thrown into the groove-like recess and the other electrode formed on the substrate are similarly connected through the other hole of the groove-like recess. With such connection, a jumper process can be performed between the two electrodes on the substrate. In such a jumper process, it is possible to twist the electric wire by avoiding the electrodes of the substrate and the electronic component by devising the arrangement position and shape of the groove-like recess in the printing stencil. For this reason, a jumper process can be performed between two electrodes on a board | substrate, without interposing a jumper wire between the electrode of a board | substrate, and the electrode of an electronic component.
In addition, since the bottom of the groove-shaped recess of the printing stencil made of an insulating material is interposed between the electric wire and the wiring pattern of the substrate, even if the conductive material is left exposed as the electric wire, And the short circuit of the wiring pattern by the electric wire can be avoided.
Therefore, the jumper treatment is performed between the electrodes in the electronic component mounting area of the substrate while eliminating the conduction failure of both electrodes by interposing the jumper wire between the electrode of the substrate and the electrode of the electronic component, and An unexpected short circuit of the wiring pattern of the substrate due to the jumper process can be avoided.
Furthermore, the opening of the groove-like recess of the printing stencil is blocked with an adhesive tape, thereby preventing the electric wire from jumping out of the groove-like recess. As a result, even if an electric wire having a bare conductive material is used as an electric wire, it jumps out of the groove-shaped recess and contacts the electrode of the electronic component, causing an unintentional short circuit. Can be resolved.

In the invention for manufacturing an electronic circuit board with the configuration of claim 3 , one end of the covered electric wire thrown into the long hole of the printing stencil is connected to the electrode formed on the board. This connection may be performed by filling the solder paste only in the vicinity of the end of the long hole in the filling step and then melting and solidifying the solder paste, or by manual soldering. On the other hand, the other end of the electric wire thrown into the long hole and the other electrode formed on the substrate are connected in the same manner. With such connection, a jumper process can be performed between the two electrodes on the substrate. In such a jumper process, it is possible to twist the covered electric wire by avoiding the electrodes of the substrate and the electronic component by devising the arrangement position and shape of the long hole in the printing stencil. For this reason, a jumper process can be performed between two electrodes on a board | substrate, without interposing a jumper wire between the electrode of a board | substrate, and the electrode of an electronic component.
Solder paste filled in the long hole by using a covered electric wire coated with an insulating material as the electric wire and closing the opening of the long hole with an adhesive tape so as not to fill the solder paste in the long hole prior to the filling step Therefore, it is possible to avoid a situation where the wiring pattern on the substrate is short-circuited.
Therefore, the jumper treatment is performed between the electrodes in the electronic component mounting area of the substrate while eliminating the conduction failure of both electrodes by interposing the jumper wire between the electrode of the substrate and the electrode of the electronic component, and An unexpected short circuit of the wiring pattern of the substrate due to the jumper process can be avoided.

Thus, among the inventions for manufacturing an electronic circuit board according to the structure of claim 1 or claim 3 , particularly in the invention of claim 2, a groove due to the elasticity of the wire in the wire feeding step is explained for the reason described below. The electric wire can be easily put in the groove-shaped recess while preventing the protrusion from the recess. That is, the present inventors performed the electronic circuit board manufacturing method according to claim 1 using a formal wire in which a copper wire is coated with an insulating material as an electric wire. Then, when a formal line is drawn in a groove-shaped recess that is bent in a complicated shape like a crank road, the formal line cannot be permanently deformed according to its shape, and its shape is restored by its elasticity. And let it jump out of the groove-shaped recess. Next, the present inventors tried using a wire obtained by subjecting a formal wire to solder plating. Then, the solder-plated wire could be easily and permanently deformed according to the shape of the groove-shaped recess, and the jumping out of the electric wire from the groove-shaped recess could be effectively suppressed.

In particular, in the invention of claim 4 , by using a printing stencil made of polyimide having excellent heat resistance, deformation and modification of the printing stencil during heating in the melting step are suppressed. Thereby, various malfunctions caused by deforming or modifying the printing stencil in the melting step can be suppressed.

In particular, in the invention of claim 5 , the printing stencil is fixed to the substrate with a breathable adhesive tape so as not to move, so that the printing stencil closely attached to the substrate is moved and printed. The positional deviation from the stencil plate can be suppressed. Furthermore, by using a breathable adhesive tape that exhibits breathability as the fixing tape, printing is performed when the air between the printing stencil and the substrate is expanded with heating in the melting process. It is possible to escape through the breathable adhesive tape without being confined between the stencil plate and the substrate. As a result, it is possible to avoid a situation in which the printing stencil is lifted from the substrate surface due to the expansion of air in the melting step and causes a positional deviation between the printing stencil and the substrate.

In particular, in the invention of claim 6 , the electric wire or the covered electric wire can be securely connected by soldering both ends of the electric wire or the covered electric wire put into the groove-like recess or the long hole of the printing stencil to the electrode of the substrate, respectively. It can be fixed to make the jumper treatment more reliable.

First, a first embodiment of an electronic circuit board manufacturing method to which the present invention is applied will be described.
FIG. 1 is a perspective view showing an electronic circuit board manufactured by the electronic circuit board manufacturing method according to the first embodiment. In the figure, this electronic circuit board has a mother board 1 made of PWB (Printed Wiring Board) or the like. On the mother substrate 1, electronic components such as a bare chip 2, QFP 3, and BGA 4 are mounted.

  FIG. 2 is a perspective view showing the electronic circuit board 1 with the BGA (4) removed. As shown in the figure, a plurality of protruding electrode arrays and a wiring pattern extending from them are formed in the BGA placement area of the mother substrate 1.

  FIG. 3 is an enlarged plan view showing a part of the BGA placement area of the mother substrate 1. In the figure, an electrode array composed of a plurality of round electrodes 5 is formed in the BGA placement region of the mother substrate. In addition, a wiring pattern including a plurality of lead wires 6 extending from the electrode 5 is also formed. Since this mother substrate 1 has undergone a design change, it is necessary to perform jumper processing as indicated by the dotted line in the figure. Specifically, this is a jumper process for short-circuiting the electrode 5 indicated by the arrow A in the figure and the electrode 5 indicated by the arrow B in the figure. Further, a jumper process for short-circuiting the electrode 5 indicated by the arrow C in the drawing and the electrode 5 indicated by the arrow D in the drawing is also required.

  However, the jumper wires in each jumper process need to be routed along a route that spans between the plurality of lead wires 6 as shown by dotted lines in the figure. There is a risk of shorting the wire 6. In this mother substrate 1, a gap L1 (see FIG. 4) between two adjacent electrodes 5 is 0.55 [mm].

  FIG. 5 is a partial perspective view showing a stencil printing mask used in the electronic circuit board manufacturing method according to the first embodiment. In the figure, the printing mask 10 is a polyimide sheet having a thickness of 125 [μm] formed with a printing pattern composed of a plurality of through holes 11. Each through-hole 11 of this printed pattern individually corresponds to each electrode 5 of the electrode pattern of the mother substrate 1 shown in FIG.

  The print mask 10 has two groove-like recesses 12 in addition to the print pattern. These groove-like recesses 12 are formed so as to avoid the plurality of through holes 11 corresponding to the plurality of electrodes (5) of the mother substrate (1). Moreover, as shown in FIG. 6, it does not penetrate from the mask front surface to the back surface, but has a depth t2 (100 μm) smaller than the thickness t1 with respect to a polyimide sheet having a thickness t1 (125 μm). It has been dug down. The width w1 of the groove-like recess 12 is 20 [μm].

  In FIG. 5 shown above, both ends of the groove-like recess 12 on the right side in the drawing are through holes 11 respectively. Of these two through holes 11, the through hole 11 indicated by the arrow a in the figure corresponds to the electrode 5 indicated by the arrow A of the mother substrate 1 previously shown in FIG. Moreover, the through-hole 11 shown by the arrow b respond | corresponds to the electrode 5 shown by the arrow B of the mother board | substrate 1 of FIG.

  Both ends of the groove-like recess 12 on the left side in FIG. Of these two through holes 11, the through hole 11 indicated by the arrow c in the figure corresponds to the electrode 5 indicated by the arrow C of the mother substrate 1 previously shown in FIG. Further, the through hole 11 indicated by the arrow d corresponds to the electrode 5 indicated by the arrow D of the mother substrate 1 of FIG.

  In the electronic circuit board manufacturing method according to the first embodiment, the above-described BGA (4) is fixed on the mother board 1 using the printing mask 10 having such a configuration. As shown in FIG. 7, the outline of the process is as follows: adhesion step, mask fixing step as a stencil fixing step, wire feeding step, wire soldering step, recess closing step, filling step, placing step, melting step, curing step The tape peeling process is performed in this order.

  FIG. 8 is a schematic configuration diagram showing a positioning device used in the electronic circuit board manufacturing method. This positioning device includes a support base 20, an X table 21 provided on the support table 20 so as to be slidable in the X direction which is the horizontal direction in the drawing, and a sliding movement on the support table 20 in the Y direction which is the depth direction in the drawing. Y table 22 provided so as to be possible. An optical monitoring device 23 for magnifying and observing the mother substrate 1 is also provided. Furthermore, a component suction nozzle (not shown) for placing the electronic component on the mother substrate 1 while sucking the electronic component, and a monitor (not shown) for projecting an image are also provided.

  The above-described contact process is a process for bringing the above-described print mask 10 into close contact with the BGA placement region of the mother substrate 1. At the time of this close contact, the print mask 10 needs to be positioned and contacted so that the print pattern exactly overlaps the electrode pattern of the mother substrate 1. In this electronic circuit board manufacturing method, this positioning is performed using the positioning device shown in FIG. Specifically, first, the mother substrate 1 is placed on the Y table 22 so that the BGA mounting surface is on the upper side in the gravity direction, and is fixed on the Y table 22 by a clamper (not shown). Next, the printing mask 10 is lightly placed on the BGA placement area of the mother substrate 1 by hand. Then, the print mask 10 is slid and moved by hand so that the print pattern and the electrode pattern are exactly overlapped while referring to the enlarged image displayed by the optical monitoring device 23. Since the printing mask 10 made of a polyimide sheet having a thickness of 125 [μm] is translucent, in the enlarged image by the optical monitoring device 23, the electrode pattern of the mother substrate 1 thereunder is seen through the printing mask 10. appear. In addition, you may confirm the relative position of the printing mask 10 and the mother board | substrate 1 using a magnifier (microscope) instead of the optical monitoring apparatus 23. FIG.

  When the printing mask 10 is positioned so that the printing pattern and the electrode pattern are perfectly overlapped, the mask fixing process is performed while firmly pressing the printing mask 10 with one hand so as not to be displaced. This mask fixing step is a step for fixing the printing mask 10 positioned on the mother substrate 1 on the mother substrate 1 with an adhesive tape. As shown in FIG. 9, the adhesive tape 13 is attached to each of the four sides of the rectangular print mask 10 to fix the print mask 10 on the mother substrate 1.

  As for the adhesive tape, it is desirable to use a breathable heat-resistant tape that exhibits breathability and moderate heat resistance. This is for the reason explained below. That is, in this electronic circuit board manufacturing method, in the latter half of the series of processes, the printing mask 10 and the BGA (not shown) are heated to perform a melting step for melting the solder. During the melting step, the air between the mother substrate 1 and the printing mask 10 adhered to the mother substrate 1 expands with heating. If a non-breathable adhesive tape 13 is used, there is no escape space for the expanded air, so that the air pushes up the print mask 10 and floats up from the substrate surface. Then, due to this lifting, the solder in each through hole 11 of the printing mask 10 is not firmly attached to each electrode 5 of the mother substrate 1 and is hardened, resulting in poor conduction, or the position of each electrode and the solder printing pattern. It will cause misalignment. Therefore, in this electronic circuit board manufacturing method, a breathable heat-resistant tape that exhibits breathability is used as the adhesive tape 13. As a result, the air expanded between the printing mask 10 and the mother substrate 1 can be released outside through the adhesive tape 13. As a result, the above-described conduction failure and positional deviation can be effectively suppressed.

  About the adhesive tape 13, it is necessary to use what shows heat resistance higher than the heating temperature in the below-mentioned melting process. In this electronic circuit board manufacturing method, the BGA is heated to a maximum of about 240 [° C.] in the melting step described later, and therefore, the adhesive tape 13 having a heat resistant temperature of 240 [° C.] or higher is used. An example of a breathable heat resistant tape that can achieve both heat resistance and good breathability is Tessa Tape (Tesa DBF # 4302) manufactured by Tessa Tape Co., Ltd.

  If the printing mask 10 is fixed on the mother board | substrate 1 with the adhesive tape 13, next, an electric wire insertion process is implemented. This wire feeding step is a step for feeding a jumper wire as a wire into the groove-like recess 12 of the printing mask 10 fixed on the mother substrate 1. Specifically, as shown in FIG. 10, the electric wires 14 cut into approximately the same dimension as the length of each of the two groove-shaped recesses 12 are bent into the same shape as the recesses and are put into the recesses. Then, the inserted electric wire 14 is wound between the two through holes 11 respectively disposed at both ends in the length direction in the groove-shaped recess 12.

  As the electric wire 14, it is desirable to use one having a surface plated with solder. This is for the reason explained below. That is, when the present inventors used a formal wire in which a copper wire is coated with an insulating material as the electric wire 14, it is very possible to throw it into the groove-like recess 12 without causing partial protrusion. It became difficult. As shown in the figure, when the formal line is wound on the groove-shaped recess 12 bent in a complicated shape such as a crank road, the formal line cannot be permanently deformed according to its shape, The shape is restored, and it jumps out of the groove-shaped recess. Therefore, the present inventors next tried using a formal solder plated wire obtained by soldering a formal wire as the electric wire 14. As a result, the formal solder-plated wire can be easily and permanently deformed according to the shape of the groove-shaped recess 12, and jumping out of the wire from the groove-shaped recess 12 due to elasticity can be effectively suppressed. Therefore, by using a solder-plated wire 14 as an electric wire 14, it is possible to prevent the wire 14 from popping out from the groove-like recess 12 due to the elasticity of the wire 14 and easily cause the electric wire to be put into the groove-like recess 12.

  As shown in FIG. 10, the ends of the electric wires 14 are stripped of the insulation material and the solder plating, respectively, to expose the internal copper wires 14a.

  If the electric wire 14 is thrown in in each of the two groove-shaped recessed parts 12, next, an electric wire soldering process will be implemented. This wire soldering step is a step for soldering and fixing the both ends of the wire 14 put into the groove-like recess 12 to the electrodes of the mother board 1 respectively. Specifically, among the two electric wires 14 shown in the figure, the one on the right side in the figure is a jumper for short-circuiting the electrode 5 previously indicated by the arrow A and the electrode 5 indicated by the arrow B in FIG. Is a line. Of these two electrodes 5, the one shown by arrow B has a donut shape as shown in FIG. 11, and has a through hole 5a in the middle. Further, as shown in FIG. 12, the same thickness as the mother substrate 1 is formed so as to be exposed on the front surface and the back surface of the mother substrate 1. For the electrode 5 having such a configuration, as shown in FIG. 13, one end of the electric wire 14 that is bent is inserted into the through hole 5 a, and the electric wire 14 is moved from the front surface side to the rear surface side of the mother substrate 1. To penetrate. And the front-end | tip part which penetrated and protruded from the back surface is manually soldered to the back surface of the electrode 5 with the solder 30 like illustration.

  On the other hand, the electrode 5 previously indicated by the arrow A in FIG. 3 does not have a through hole in the middle. Further, it is formed so as to be exposed only on the front surface side of the mother substrate 1. For such an electrode 5, as shown in FIG. 14, the solder 30 melted with a soldering iron is dropped through the through hole 11 of the printing mask 10, and the copper wire 14 a on the other end side of the electric wire 14 is moved to it. Solder.

  Although the example of soldering the electric wire 14 on the right side in FIG. 10 described above has been described, both ends of the electric wire 14 on the left side in the figure are also soldered in the same manner. One end side corresponding to the through hole 11 indicated by d in the figure is bent and soldered to the electrode on the back side of the mother substrate 1 (not shown). Further, the other end side corresponding to the through hole 11 indicated by c in the drawing is soldered to the electrode by the molten solder dropped through the through hole 11 without being bent.

  After the two electric wires 14 are soldered to the mother board 1, a recess closing process is performed next. In this recess closing step, an adhesive tape is applied to the front surface (BGA mounting surface) of the mother substrate 1 to close the opening of the groove-shaped recess 12 into which the electric wire 14 has been inserted. This is a process for preventing the electric wire 14 from jumping out. The adhesive tape is preferably pasted so as to block the entire region of the groove-shaped recess 12, but the plurality of through holes 11 corresponding to the respective electrodes (5) of the mother substrate 1 are not blocked. You need to be careful. If the through-hole 11 is closed, the solder paste cannot be filled into the through-hole 11 in the subsequent filling step, and the electrode (5) of the mother substrate 1 and the protruding electrode of the BGA (4) This is because conduction failure occurs between the two. In the first embodiment, in order to avoid a situation where the through hole 11 of the printing mask 10 is blocked with the adhesive tape, the adhesive tape is applied only to the substrate region where the through hole 11 is not arranged in an array. I have to. First, the adhesive tape is applied only to the non-electrode arrangement region R shown by the one-dot chain line in FIG. 3 to block only the portions in the non-electrode arrangement region R among all the portions of the groove-shaped recess 12. . In addition, if the adhesive tape thinner than the distance (0.55 mm in this example) between each through-opening 11 is used, the location in the electrode arrangement | positioning area | region in the groove-shaped recessed part 12 may be obstruct | occluded avoiding the through-hole 11. FIG. Although it is possible, the work efficiency is remarkably deteriorated.

  As for the pressure-sensitive adhesive tape used in the recess closing step, it is desirable to use one having a heat resistance temperature higher than at least the heating temperature in the melting step described later. However, the air permeability between the printing mask 10 and the mother substrate 1 is ensured by the air-permeable heat-resistant tape used in the above-described mask fixing step, so that it is necessary to use a gas-permeable adhesive tape used in the recess closing step. There is no. In this 1st Embodiment, the non-breathable polyimide tape was used as the adhesive tape for a recessed part closure process at the heat-resistant temperature of 240 [degreeC] or more. An example of such a polyimide tape is Scotch Mark Kapton (registered trademark) film tape (No. 5413) manufactured by Sumitomo 3M Limited.

  After the opening of the groove-like recess 12 of the print mask 10 is partially closed with the adhesive tape, next, the solder paste is filled into each through hole 11 of the print mask 10 by a filling process. FIG. 15 is a partial cross-sectional view showing the mother substrate 1 and the printing mask 10. In the filling step, first, a solder paste is placed on the printing mask 10 fixed on the mother substrate 1. Then, as shown in the figure, the solder paste 31 is imprinted on the printing mask 10 by the squeegee 32, and the solder paste 31 is filled in each through hole 11 of the printing mask 10. Since each through hole 11 of the printing mask 10 is positioned right above each electrode 5 of the mother substrate 5, the solder paste 31 filled in each through hole 11 is positioned above the electrode 5. . In the non-electrode arrangement region of the mother substrate 1, as indicated by the dotted line in the figure, the groove-like recess 12 of the printing mask 10 is closed by the adhesive tape 15, so that the solder paste 31 is placed in the groove-like recess 12. There is no such thing as filling. The solder paste 31 contains an infinite number of solder fine particles and a flux that removes an oxide film of the solder fine particles when the solder is melted. Further, the flux contains a resin component and a solvent. ing.

  If the solder paste 31 is filled in each through-hole 11 of the printing mask 10 by the filling step, the excess solder paste 31 is removed from the printing mask 10 and then the placing step is performed. In this mounting process, first, as shown in FIG. 16, the BGA 4 is sucked by the component suction nozzle 24 corresponding to the mother board 1 through the optical monitoring device 23 so that the protruding electrode 4a side faces downward in the gravity direction. Fix it. The optical monitoring device 23 synthesizes the planar image of the BGA 4 on the upper side and the planar image of the printing mask 10 directly below the optical monitoring device 23 so that their planar relative positions are the same as the actual one. 25 is projected. The operator slides the X table 22 and the Y table 21 while watching the image displayed on the monitor 25 connected to the optical monitoring device 23, and directly on the mother substrate 1 directly below each protruding electrode 4 a of the BGA 4. Positioning is performed so that each through-hole 11a of the fixed printing mask 10 is positioned. After the alignment is performed while viewing the projected image in this way, the optical monitoring device 23 is removed and the component suction nozzle 24 is slowly lowered vertically. Then, as shown in FIG. 17, after the tips of the protruding electrodes 4a of the BGA 4 are inserted into the through-holes 11 of the printing mask 10, the BGA 4 is separated from the component suction nozzle 24 by stopping the vacuum function, and then on the printing mask 10. Mount on. Each protruding electrode 4a of the BGA 4 is made of a meltable solder.

  After the BGA 4 is mounted on the printing mask 10 by the mounting process, a melting process is performed. In this melting step, hot air is blown from the hot air nozzle (not shown) toward the upper surface of the BGA 4 and the mother substrate 1 is heated from the back side by a heating means such as a heater (not shown). As a result, the solder constituting each protruding electrode 4a of the BGA 4 and the solder grains in the solder paste (31) filled in each through hole 11 of the printing mask 10 are heated and melted. Then, the flux in the solder paste (31) is volatilized, and as shown in FIG. 18, the molten solder of each protruding electrode 4a of the BGA 4 and the molten solder particles in each through hole 11 of the printing mask 10 are formed. Integrate. And each pad (planar electrode) 4b of BGA4 and each electrode 5 of the mother board | substrate 1 are bridge | crosslinked.

  In such a melting step, it is desirable that the solder paste 31 in each through-hole 11 of the printing mask 10 is kept for 20 seconds or more in a state where the temperature is raised to 210 to 240 [° C.]. This is for the reason explained below. That is, when the present inventors performed the electronic circuit board manufacturing method according to the first embodiment, the time during which the temperature of the solder paste (31) is raised to 210 to 240 [° C.] is less than 20 seconds. And found that continuity failure may occur. This is because the protruding electrodes 4a and the solder particles in the paste could not be sufficiently integrated due to insufficient melting of the solder particles and protruding electrodes 4a.

  When the protruding electrode 4a of the BGA 4 and the solder grains in the through hole 11 are integrated by a melting process, a curing process is performed. In this curing step, heating by the hot air or heating means described above is stopped, and the molten solder (4a + 31) is cooled. Due to this cooling, the solder melted between the BGA 4 and the mother substrate 1 is cured to form bump-shaped electrodes that electrically connect the pads 4b of the BGA 4 and the electrodes 5 of the mother substrate 1, and the BGA 4 Is fixed on the mother substrate 1.

  When the BGA 4 is fixed on the mother substrate 1 by such a curing process, the above-described breathable heat-resistant tape 13 that has fixed the printing mask 10 is peeled off from the printing mask 10 and the mother substrate 1 to complete the electronic circuit board. .

  Next, a second embodiment of an electronic circuit board manufacturing method to which the present invention is applied will be described. Note that most of the work steps in the electronic circuit board manufacturing method according to the second embodiment are the same as those of the electronic circuit board manufacturing method according to the first embodiment already described. Therefore, here, in the electronic circuit board manufacturing method according to the second embodiment, only the points different from the first embodiment will be described, and the points not particularly mentioned are the same as those of the first embodiment.

  FIG. 19 is a partial perspective view showing the printing mask 10 used in the electronic circuit board manufacturing method according to the second embodiment. In the same figure, the printing mask 10 has the printing pattern which consists of several through-holes 11 in the polyimide sheet of thickness 125 [micrometer] similarly to what concerns on 1st Embodiment. However, unlike the one according to the first embodiment, there is no groove-like recess for inserting a jumper wire. Instead, as shown in the figure, a long hole 16 for inserting a jumper wire is provided. The planar shape of the elongated hole 16 is the same as the groove-shaped recess (12) of the printing mask according to the first embodiment, whereas the groove-shaped recess does not penetrate from the mask front surface to the back surface. The elongated hole 16 penetrates as shown in FIG. In the electronic circuit board manufacturing method according to the second embodiment, jumper wires are put into the long holes 16 penetrating in this way.

  As this jumper wire, an electric wire whose surface is covered with an insulating material, such as a formal wire, is used instead of solder plating on the surface as in the first embodiment. This is because if the surface is made of a conductive material, it short-circuits between the leads of the extension pattern of the mother board (1) in the long hole 16. If the surface of the electric wire is covered with an insulating material, even if it straddles the plurality of lead wires (6) of the mother board (1) in the long hole 16, they are not short-circuited.

  In the electronic circuit board manufacturing method according to the second embodiment, a long hole closing process is performed instead of the recess closing process in the electronic circuit board manufacturing method according to the first embodiment. This is a process for closing almost all the openings of the long holes 16 with a heat-resistant adhesive tape. In the recess closing step in the first embodiment, in consideration of work efficiency, no adhesive tape is applied to the non-electrode arrangement region (R) in the mother substrate (1), and openings are provided in the groove-like recess portions there. It remained unobstructed. However, in the electronic circuit board manufacturing method according to the second embodiment, the adhesive tape is also applied to the non-electrode arrangement region (R), and the opening of the long hole portion there is also tightly closed. This is because if the long hole 16 is filled with a large amount of solder paste in the subsequent filling step, the lead wires of the wiring pattern of the mother board (1) may be short-circuited. However, it is not always necessary to block the entire region of the long hole 16. In the long hole 16, a portion that does not correspond to the wiring pattern of the mother board (1) or a portion that does not straddle a plurality of lead wires. May not be occluded. In particular, the following can be realized by leaving the portion corresponding to the electrode (5) to be subjected to the jumper process of the mother substrate (1) open without being closed. That is, it is possible to fill the solder paste with the soldering process in the filling process in the opened position, and to connect the jumper wire and the electrode (5) by soldering. In the electronic circuit board manufacturing method according to the second embodiment, from such a point of view, only the portions corresponding to the electrodes to be subjected to the jumper process (both ends of the long holes 16 in this example) in the long holes 16 are adhesive tapes. Do not close the opening with, leave it open. Then, as shown in FIG. 21, in the filling step, the solder cream 31 is filled into both end portions of the long hole 16 together with a through hole (not shown). In addition, about the electric wire 14 thrown into the long hole 16, the coating | cover of both ends is peeled off similarly to 1st Embodiment, and the internal copper wire 14a is exposed. Moreover, after the copper wire 14a thus exposed is manually soldered to the electrode 5 to be subjected to the jumper process of the mother board 1 in the same manner as in the first embodiment, the long hole 16 is subjected to the long hole closing process. Alternatively, the entire region may be closed with an adhesive tape so that the solder paste is not filled in the elongated hole 16 at all.

  As described above, in each embodiment, the example in which the mounting area of the BGA 4 as the electronic component on the mother substrate 1 is subjected to the jumper processing has been described. However, the present invention can be applied not only to the BGA but also to an electronic circuit board manufacturing method in which a mounting area of other bottom electrode array type electronic components such as LGA and CSP is jumpered. In the case where the mounting area of the electronic component in which only the pad is formed without the protruding electrode made of solder formed on the lower surface of the package unlike the LGA, the following process may be performed. That is, prior to mounting the electronic component, protruding electrodes may be formed on the pads. As a method for forming the protruding electrode, a solder paste printing method using a printing mask may be used. In this case, it is not always necessary to melt the electrode patterns made of the solder paste prior to mounting the electronic components. The electronic component may be mounted in a paste state.

The perspective view which shows the electronic circuit board manufactured by the electronic circuit board manufacturing method which concerns on 1st Embodiment. The perspective view which shows the same electronic circuit board of the state which removed BGA. The top view which expands and shows a part of BGA mounting area | region of the mother board | substrate in the same electronic circuit board. The schematic diagram for demonstrating the gap | interval between the electrodes in the mother board | substrate. The fragmentary perspective view which shows the printing mask used with the same electronic circuit board manufacturing method. The expanded partial perspective view which shows the groove-shaped recessed part of the same printing mask, and its periphery. The flowchart which shows each work process in the same electronic circuit board manufacturing method. The schematic block diagram which shows the positioning apparatus used for the same electronic circuit board manufacturing method. The enlarged plan view which shows the mother board | substrate of the state which fixed the printing mask. The fragmentary perspective view which shows the same printing mask from which an electric wire is going to be thrown into a groove-shaped recessed part. The fragmentary perspective view which shows one of the two electrodes used as the object of a jumper process in the mother board | substrate. The expanded sectional view which shows the one electrode. The expanded sectional view which shows the one electrode, a printing mask, and an electric wire. The expanded sectional view which shows the other of the same two electrodes, a printing mask, and an electric wire. The expanded sectional view which shows the mother board | substrate in the filling process of the electronic circuit board manufacturing method, and a printing mask. The block diagram which shows the same positioning device of the state which made the components suction nozzle stand by. The expanded sectional view which shows the mother board | substrate in the mounting process of the electronic circuit board manufacturing method, the printing mask, and BGA. The expanded sectional view which shows the mother board | substrate in the melting process of the electronic circuit board manufacturing method, the printing mask, and BGA. The fragmentary perspective view which shows the printing mask used with the electronic circuit board manufacturing method which concerns on 2nd Embodiment. The expanded partial perspective view which shows the long hole of the printing mask, and its periphery. The expanded sectional view which shows the mother board | substrate in the filling process of the electronic circuit board manufacturing method, and the printing mask.

Explanation of symbols

1 Mother board (board)
4 BGA (electronic parts)
4a Projection electrode 4b Pad (Each electrode in the electrode pattern of an electronic component)
5 electrodes (part of electrode pattern)
10 Print mask (second half)
11 Through-hole 12 Groove-shaped recess 13 Adhesive tape (Breathable adhesive tape)
14 Wire 15 Adhesive tape (for closing recesses or long holes)
16 Long hole 30 Solder 31 Solder paste

Claims (6)

An adhesion step of closely attaching a printing stencil having a hole pattern corresponding to the electrode pattern to a substrate on which the electrode pattern is formed; and solder paste in each hole of the printing stencil closely attached to the substrate A filling step for filling, a placing step for placing an electronic component having an electrode pattern formed on the lower surface on the printing stencil, and heating the solder paste in each hole to dispose the solder particles in the solder paste. An electronic circuit board comprising: a melting step for melting, and a curing step in which the melted solder is cured by cooling and each electrode in the electrode pattern of the substrate is soldered to each electrode in the electrode pattern of the electronic component. In an electronic circuit board manufacturing method for manufacturing
The printing stencil is made of an insulating material and has a groove-shaped recess and at least two holes formed in the groove-shaped recess. After the adhesion step, the groove-shaped recess A wire loading step for feeding an electric wire into the groove-shaped recess so as to make the gap between these two holes inside, and a recess closing that closes the opening of the groove-shaped recess after closing the wire with an adhesive tape a step from the embodiment, an electronic circuit board manufacturing method characterized by carrying out the above filling step. In the electronic circuit board manufacturing method according to claim 1,
A method of manufacturing an electronic circuit board, wherein the wire has a surface plated with solder . An adhesion step of closely attaching a printing stencil having a hole pattern corresponding to the electrode pattern to a substrate on which the electrode pattern is formed; and solder paste in each hole of the printing stencil closely attached to the substrate A filling step for filling, a placing step for placing an electronic component having an electrode pattern formed on the lower surface on the printing stencil, and heating the solder paste in each hole to dispose the solder particles in the solder paste. An electronic circuit board comprising: a melting step for melting, and a curing step in which the melted solder is cured by cooling and each electrode in the electrode pattern of the substrate is soldered to each electrode in the electrode pattern of the electronic component. In an electronic circuit board manufacturing method for manufacturing
The printing stencil is made of an insulating material and has a groove-like long hole corresponding to the shape of the circuit correction wiring, and the surface is covered with an insulating material after the adhesion step. An electric wire feeding step of throwing the covered electric wire into the long hole so as to run along the longitudinal direction of the long hole, and an oblong hole that closes the opening of the long hole into which the covered electric wire has been charged with an adhesive tape An electronic circuit board manufacturing method, wherein the filling step is performed after the closing step. In the electronic circuit board manufacturing method according to any one of claims 1 to 3 ,
A method for producing an electronic circuit board, comprising using a polyimide made of polyimide as the printing stencil. In the electronic circuit board manufacturing method according to any one of claims 1 to 4 ,
A stencil fixing step of fixing the printing stencil to the substrate with a breathable pressure-sensitive adhesive tape that exhibits air permeability is performed between the adhesion step and the electric wire feeding step, and after the curing step, the breathability A method for producing an electronic circuit board, comprising performing a tape peeling step of peeling an adhesive tape from the printing stencil. In the electronic circuit board manufacturing method in any one of Claims 1 thru | or 5 ,
An electronic circuit board manufacturing method comprising: performing an electric wire soldering step of soldering both ends of the electric wire or the covered electric wire to the electrodes of the substrate after the electric wire charging step, and then performing the filling step. .

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