JP7062030B2 - Electronic board unit and its manufacturing method - Google Patents

Description

The present invention relates to an electronic substrate unit and a method for manufacturing the same.

Application method and process order of the joint material used for the joint formed by fixing leadless parts and leaded parts, which are surface mount parts, to the electrode pads of the printed wiring board, mounting method and process order of the surface mount parts. There are various things. For example, according to the following Patent Document 1 “Electronic component mounting substrate and electronic component mounting method”, solder paste is applied to the electrode land on the mounting substrate in the coating process, and the electronic component is mounted on the electrode land in the temporary mounting process. In the reflow process, a series of steps to reflow the solder paste in the reflow furnace are repeated for each electronic component category, and it is said that the temperature can be set lower than the heating temperature in the reflow furnace in the reflow process before one reflow process. There is.

Further, according to the following Patent Document 2 "Cream Solder Supply Method", the cream solder supply volume per unit area is changed between the first step and the second step by using two metal masks having different thicknesses. In addition, by providing a recess on the back surface of the metal mask used in the second step, it is possible to avoid interference between the cream solder supplied on the substrate in the first step and the metal mask, and apply the solder with high accuracy. It is said that it can be done.

Further, according to the following Patent Document 3 "Method of applying cream solder to a printed wiring board", cream solder is applied to a fine electrode pattern using a thin mask material, and an opening of an electrode portion and a metal are normally placed at the position of the electrode pattern. Printing of the mask Cream solder printing with a recess at the position of the fine electrode pattern on the surface side that comes into contact with the wiring plate Cream solder printing using a metal mask is performed in a separate process, and the cream solder applied to the fine electrode pattern It is said that it is possible to use a different type of cream solder that is normally applied to the electrode pattern.

Japanese Unexamined Patent Publication No. 2001-185842 (FIGS. 2, FIG. 3, abstract) Japanese Unexamined Patent Publication No. 5-212852 (Fig. 3, summary) Japanese Unexamined Patent Publication No. 4-332192 (Fig. 7, summary)

(1) Explanation of Problems of Conventional Techniques However, in the method of mounting an electronic component according to Patent Document 1, the reflow process is performed twice per one side, and in the case of mounting an electronic component, the reflow process is performed at least three times. Therefore, there arises a problem that the thermal stress becomes excessive for the mounting board and the electronic components mounted before one reflow process. In addition, since the process after the heating temperature in the reflow furnace in one reflow process is set lower, the melting point of the solder paste used in one reflow process is higher than that of the solder paste in the subsequent process. There is a problem that the electronic components mounted in the reflow process need to have higher heat resistance than the electronic components mounted after one reflow process. Further, since the reflow process is performed at least twice per one side, there is a problem that the production time becomes long.

Further, in the method of supplying the cream solder multiple times on the substrate according to Patent Document 2, the optimum amount of application of the minute parts and the conventional parts is a metal mask that always supplies the cream solder in the optimum amount to various electronic parts. It is necessary to prepare for each amount, which causes a problem that the number of times the coating amount is adjusted increases. In addition, since the emphasis is on supplying the optimum amount of cream solder, there is a possibility that the supply will be insufficient for large parts with large flatness of the electrodes, which causes a problem of impairing mounting reliability. ..

Further, in the method of applying different types of cream solder applied to the fine electrode pattern and the cream solder applied to the normal electrode pattern according to Patent Document 3, the upper limit of the furnace set temperature of the reflow furnace and the temperature at which the bonding material is heated and melted are used. The relationship between the reflow heat resistance performance of the components to be mounted is not shown, and there is a problem that the reliability of the components to be mounted is impaired.

(2) Description of Purpose of the Invention An object of the present invention is to mount mounting components of terminals having different terminal shapes or flatness accuracy on a printed wiring board on the same mounting surface so that they can be fixed by one reflow heating. It is an object of the present invention to provide an electronic circuit board unit and a manufacturing method thereof in which productivity is improved, bonding reliability of mounted components is improved, thermal stress on mounted components and printed wiring boards is reduced, and reliability is improved. ..

The electronic substrate unit according to the present invention has a rectangular shape with a built-in element, and has two or more electrodes formed by a leadless component having a leadless electrode having an electrode formed on the surface and a metal terminal drawn from the element. Leaded parts with leaded electrodes, bonding materials for heating and melting in a reflow furnace, printed wiring boards with electrode pads on one or both sides, leadless electrodes and electrode pads, and leads with leads. An electronic board unit having a joint portion formed by fixing an electrode pad and an electrode pad with a joint material, and the leadless parts and leaded parts have heat resistance performance equal to or higher than the melting temperature of the joint material, and the joint portion. Is a plurality of first to nth (n is an integer of 3 or more) grouped so that the area-equivalent coating thickness, which is the value obtained by dividing the volume of the bonding material by the area of the electrode pad, coincides stepwise. The coating thickness group is provided, and the relationship between the area-converted coating thicknesses of the plurality of coating thickness groups is that the first coating thickness group <second coating thickness group <nth coating thickness group, and the bonding material of the first coating thickness group, and The bonding material of the second coating thickness group or the second coating thickness group to the nth coating thickness group is made of the same type or two or more kinds of materials.

The method for manufacturing an electronic substrate unit according to the present invention is a rectangular body having a built-in element, a leadless component having a leadless electrode on the surface, and a lead which is two or more terminals made of metal drawn from the element. Parts with leads equipped with attached electrodes, bonding materials for heating and melting by a reflow furnace, printed wiring boards provided with electrode pads to which the bonding materials are applied on one or both sides, leadless electrodes and electrode pads, and The leaded electrode and the electrode pad are provided with a joint formed by being fixed by a bonding material, and the leadless parts and the leaded parts have heat resistance performance equal to or higher than the upper limit of the furnace set temperature of the reflow furnace. The upper limit of the furnace set temperature is a temperature equal to or higher than the temperature at which the bonding material is heated and melted, and the bonding material applied to the electrode pad is a value obtained by dividing the volume of the bonding material by the area of the rectangular electrode pad. Joining of the first coating thickness group, which comprises a plurality of coating thickness groups from the first to the nth (n is an integer of 3 or more) in which the area-converted coating thickness is grouped into different thicknesses and fixes the leadless electrode. The coating thickness of the material is obtained by dividing the coating width of the bonding material on the short side side of the electrode pad to which the leadingless component having the narrowest area of the leadless electrode is fixed by the coating thickness of the bonding material. The coating thickness of the bonding material of the second coating thickness group or the second coating thickness group to the nth coating thickness group to which the electrode with the lead is fixed is the electrode pad. The coating thickness is equal to or greater than the flatness of the leaded electrode, which is the degree of variation in the height of the leaded electrode in the direction perpendicular to the printed wiring board provided with. The coating thickness group <second coating thickness group <nth coating thickness group, and the temperature at which the bonding material is heated and melted is lower than the furnace set temperature of the reflow furnace, and the bonding material of the first coating thickness group, And the second coating thickness group or the bonding material of the second coating thickness group to the nth coating thickness group is a method for manufacturing an electronic substrate unit made of the same type or two or more kinds of materials, and the leadless electrode of the leadless component is used. The process of applying the bonding material to the electrode pad to be fixed with the coating thickness of the first coating thickness group and the bonding material to the electrode pad to which the leaded electrode of the lead-attached component is fixed with the coating thickness of the second coating thickness group. The process of applying the bonding material to the electrode pad to which the leaded electrode of the leaded component is fixed with the coating thickness of the nth coating thickness group, and the leadless of the leadless component. The step of mounting the leaded electrode and the leaded electrode of the leaded component on the jointing material provided on the electrode pad to which each is fixed, and the joining material is heated and melted by one reflow heating in the reflow furnace. It includes a step of forming a joint portion to which a leadless electrode and an electrode pad, and a leaded electrode and an electrode pad are fixed by a melted bonding material.

As described above, the electronic circuit board unit and its manufacturing method according to the present invention include leadless parts and lead-attached parts having a reflow heat resistance of the reflow furnace at a temperature higher than the furnace set temperature, and a bonding material applied to a printed wiring board. A joint portion consisting of a first coating thickness group and a second coating thickness group or a second coating thickness group to an nth coating thickness group in which the coating thicknesses, which are the values obtained by dividing the volume of the electrode pad by the area of the electrode pad, are stepwise matched. It is provided with a bonding material of the same type or two or more types that are heated and melted at a temperature lower than the set temperature of the reflow oven. Therefore, since mounting components of terminals with different terminal shapes or flatness accuracy can be mounted on the same mounting surface and fixed by one reflow heating, the process of reducing the number of reflows and compensating for the shortage of bonding material becomes unnecessary and productivity is improved. Has the effect of In addition, there is an effect that the thermal stress on the mounted parts and the printed wiring board can be reduced. In addition, there is an effect that the failure rate of mounted parts and printed wiring boards can be reduced.

It is a figure which showed the relationship between the reflow heat resistance performance of a component and the set temperature of a reflow furnace when the bonding material of the electronic board unit which concerns on Embodiment 1 and a coating thickness group are one-to-one. It is a figure which showed the relationship between the reflow heat resistance performance of a component and the set temperature of a reflow furnace when the bonding material of the electronic substrate unit and the coating thickness group which concerns on Embodiment 1 are one-to-six. It is a figure which showed the relationship between the flatness of the electrode of the component mounted on the electronic board unit which concerns on Embodiment 1 and the coating thickness group of a bonding material. It is a figure regarding the aspect ratio of the joining material of the electronic substrate unit which concerns on Embodiment 1. FIG. It is a figure which showed the relationship between the particle diameter of the solder of the electronic board unit which concerns on Embodiment 1, and the metal mask thickness. It is a figure which showed the relationship between the bonding material of the electronic substrate unit which concerns on Embodiment 1 and the thickness of a metal mask. It is a process drawing from the bonding material application of the electronic board unit which concerns on Embodiment 1, to component mounting and fixing. It is a block diagram of the joint material coating | component mounting process of the electronic board unit which concerns on Embodiment 1. FIG. It is a figure which showed the process of the manufacturing method of the electronic board unit which concerns on Embodiment 1. It is a figure which showed the other joining material of the electronic substrate unit which concerns on Embodiment 1. FIG.

Hereinafter, an electronic substrate unit according to an embodiment of the present invention and a method for manufacturing the same will be described with reference to the drawings. In each figure, the same or corresponding members and parts will be described with the same reference numerals.

Embodiment 1.
(1) Detailed Description of Configuration and Operation First, the modifications of FIGS. 1 and 1 showing the relationship between the reflow heat resistance performance 240 of the parts and the furnace set temperature 741 of the reflow furnace according to the first embodiment of the present invention. FIG. 2 shows the morphology, FIG. 3 shows the relationship between the flatness of the electrodes of the parts and the coating thickness group 410 of the bonding material 300, and FIG. 4 explaining the aspect ratio of the bonding material 300. , The configuration and operation thereof will be described in detail with reference to FIG. 8 which simplifies the process.

FIG. 1 shows the relationship between the furnace set temperature 741 of the reflow furnace, the reflow heat resistance performance 240 of the leadless parts 201 and the electrodes 212A and 212B with leads, which are the mounted parts, and the melting temperature of the bonding material 300. It is a figure when the material 300 and the coating thickness group 410 are one-to-one.

The coating thickness group 410, which is grouped so that the area-converted coating thickness 600, which is the value obtained by dividing the volume of the bonding material 300 by the area of the electrode pad 101 provided on the printed wiring board 100, substantially coincides in stages, is the first. The first coating thickness group 411, the second coating thickness group 412, and the nth coating thickness group (n is an integer of 3 or more) 41n, and the first coating thickness group 411 has a melting temperature 311 of the first type bonding material. The first type bonding material 301 having the first type bonding material, the second type bonding material 302 having the melting temperature 312 of the second type bonding material in the second coating thickness group 412, and the melting temperature of the nth type bonding material in the nth coating thickness group 41n. A type n bonding material 30n having 31n is used, and the melting temperature of each is lower than the furnace set temperature upper limit 742 of the reflow profile 740 set in the reflow step 731.

From the relationship between the flatness and the coating thickness shown in FIG. 3, the flatness 231 and the leaded component of the leadless electrode of the first coating thickness group 411, the second coating thickness group 412, the nth coating thickness group 41n, and the leadless component 201 When the flatness of the leaded electrode of 202A is 232A and the flatness of the leaded electrode of the leaded component 202B is 232B, the coating thickness of the first type bonding material 301 of the first coating thickness group 411 is the leadless of the leadless component 201. The flatness of the electrode is set to be thicker than 231 and thinner than the flatness of the leaded electrode 232A of the leaded component 202A, and the coating thickness of the second type bonding material 302 of the second coating thickness group 412 is set. Is set to be thicker than the flatness 232A of the leaded electrode of the leaded component 202A and thinner than the flatness 232B of the leaded electrode of the leaded component 202B, and is set to be thinner than the nth coating thickness group 41n. The coating thickness of the n-type bonding material 30n is set so as to be thicker than the flatness 232B of the leaded electrode of the leaded component 202B.

In FIG. 4, the coating thickness 401 of the coating thickness group 410 applied to the electrode pad 101 provided on the printed wiring board 100 is stable in the bonding material application step 710 in which the bonding material 300 is applied using the metal mask 500 described later. The relationship between the coating thickness 401 and the coating width 402 is such that the aspect ratio, which is the ratio of the coating width 402 divided by the coating thickness 401, is larger than 1.

The leadless component 201 having the thermal resistance performance 221 of the leadless component includes the leadless electrode 211 in which the electrode is directly formed on the surface of the rectangular body in which the element is built, and the thermal resistance performance 222A of the leaded component is provided. The leaded parts 202A and 202B each having 222B are provided with leaded electrodes 212A and 212B formed of two or more metal terminals drawn from the element, respectively, and their respective heat resistance performances are in the reflow process. It has higher heat resistance than the furnace set temperature upper limit 742 of the reflow profile 740 set in 731.

Therefore, the leadless parts 201 and the parts with leads 202A and 202B have higher heat resistance than the furnace set temperature upper limit 742 of the reflow process 731, and are further heated and melted and joined by the furnace set temperature upper limit 742 of the reflow process 731. Since the melting temperature of the type 1 bonding material 301, the type 2 bonding material 302, and the type n bonding material 30n is low, it is possible to mount each component on the printed wiring board 100 in one reflow step 731.

FIG. 2 shows a one-to-many embodiment in which the combination of the joining material 300 and the coating thickness group 410 is one-to-many with respect to the first embodiment of FIG. Hereinafter, the parts different from those in FIG. 1 will be described.

The first coating thickness group 411 has a first type bonding material 301 having a melting temperature 311 of the first type bonding material, and the second coating thickness group 412 and the nth coating thickness group 41n have a melting temperature 312 of the second type bonding material. The second-class bonding material 302 having the above is used, and the melting temperature of each is lower than the furnace set temperature upper limit 742 of the reflow profile 740 set in the reflow step 731.

Also in the embodiment shown in FIG. 2, the coating thickness of the first type bonding material 301 of the first coating thickness group 411 is determined from the relationship between the flatness and the coating thickness shown in FIG. 3, as in the first embodiment of FIG. The flatness of the leadless electrode of the leadless component 201 is set to be thicker than that of the leadless electrode 231 and the flatness of the leaded electrode of the leaded component 202A is set to be thinner than the flatness of the leaded electrode of 232A. The coating thickness is set to be thicker than the flatness 232A of the leaded electrode of the leaded component 202A and thinner than the flatness 232B of the leaded electrode of the leaded component 202B, and the second type bonding of the nth coating thickness group 41n is set. The coating thickness of the material 302 is set to be thicker than the flatness 232B of the leaded electrode of the leaded component 202B.

The coating thickness 401 of the coating thickness group 410 applied to the electrode pad 101 provided on the printed wiring board 100 is the ratio obtained by dividing the coating width 402 by the coating thickness 401 in the relationship between the coating thickness 401 and the coating width 402 from FIG. Since a certain aspect ratio is larger than 1, in the bonding material coating step 710 in which the bonding material 300 is applied using the metal mask 500 described later as in the first embodiment, the bonding material has a stable coating amount. It is possible to apply 300.

The leadless component 201 having the thermal resistance performance 221 of the leadless component includes the leadless electrode 211 in which the electrode is directly formed on the surface of the rectangular body in which the element is built, and the thermal resistance performance of the leaded component is provided. The leaded parts 202A and 202B having 222A and 222B each have leaded electrodes 212A and 212B formed of two or more metal terminals drawn from the element, and their respective heat resistance performances are reflowed. It has higher heat resistance than the furnace set temperature upper limit 742 of the reflow profile 740 set in step 731.

Therefore, similarly to the first embodiment, the leadless parts 201 and the lead-attached parts 202A and 202B have higher heat resistance than the furnace set temperature upper limit 742 of the reflow process 731, and further have higher heat resistance than the furnace set temperature upper limit 742 of the reflow process 731. Since the melting temperatures of the first-class joining material 301 and the second-class joining material 302 to be joined by heating and melting are low, it is possible to mount each component on the printed wiring board 100 in one reflow step 731.

From the above, mounting components of terminals with different terminal shapes and flatness accuracy can be mounted on the same mounting surface of the printed wiring board 100 and fixed by one reflow heating, so that the process of reducing the number of reflows and compensating for the shortage of bonding material is possible. It becomes unnecessary and has the effect of improving productivity.

Further, there is an effect that the thermal stress on the mounted component and the printed wiring board 100 can be reduced.

Further, there is an effect that the failure rate of the mounted component and the printed wiring board 100 can be reduced.

Next, the material of the joining material 300 will be described with reference to FIGS. 5 and 6.

FIG. 5 shows a case where the bonding material 300 is solder 321 which is a metal alloy and is composed of two or more kinds of pre-melting particle diameters. In FIG. 5, a small-diameter solder having a small particle diameter before melting is used for the first-class bonding material 301A, and a large-diameter solder having a large particle diameter before melting is used for the second-class bonding material 302A.

For example, if the particle size of the metal alloy of the bonded material 300 to be applied is reduced, the filling efficiency of the metal alloy particles after application will increase, and the metal alloy density per unit volume will increase. As the coating thickness increases, the coating shape tends to collapse, and at the same time, the plate release property deteriorates. In addition, the surface area of the metal alloy per unit volume becomes wider, it becomes easier to oxidize, and the frequency of replacement increases.

For example, if the particle size of the metal alloy of the bonding material 300 to be coated is increased, the filling efficiency of the metal alloy particles after coating is lowered, but when the coating thickness is increased, the coating shape is changed. At the same time as it becomes easier to keep, the plate release property improves. In addition, since the surface area per unit volume of the metal alloy particles becomes narrower, it becomes more difficult to oxidize, and the frequency of replacement decreases, so that the amount of waste decreases.

The type 1 bonding material 301A applied to the electrode pad 101 provided on the printed wiring board 100 using the first metal mask 501 is the type 2 bonding material 302A applied using the second metal mask 502. A bonding material 300 having a smaller particle size can be selected.

Therefore, when the coating thickness is thin and the coating area is narrow, small-diameter solder can be used and the metal alloy solder 321 can be coated with high filling efficiency. Further, when the coating thickness is thick and the coating area is large, a large-diameter solder is used, so that even if the coating thickness is thick, the coating can be performed in a stable coating shape. Further, the amount of waste of the bonding material 300 to be applied can be reduced.

FIG. 6 shows a case where the joining material 300 is composed of two or more different materials.

The leadless component 201 and the leaded components 202A and 202B mounted on the printed wiring board 100 each have a unique coefficient of linear expansion, and shrinkage stress is generated after the bonding material 300 is heat-cured due to the difference in the coefficient of linear expansion. Further, due to the difference in the coefficient of linear expansion, strain stress is generated due to the environmental temperature change received in the usage environment of the product and the repeated temperature change such as self-heating generated from the component.

For example, in the case of lead-attached parts 202A and 202B, the strain stress due to shrinkage stress or repeated temperature changes generated after heat curing can be relaxed by the leads after mounting, but in the case of leadless parts 201, after mounting. Since it does not have a lead that relaxes the repetitive stress, the leadless component 201 may be destroyed when the metal alloy bonding material 300 that is deformed by the repetitive stress and is difficult to relax the stress is used.

Further, in the leadless component 201 mainly made of ceramic, which is becoming smaller and smaller, cracks due to strain stress concentration on the leadless electrode 211 due to strain stress due to repeated temperature changes are more likely to occur as the size becomes smaller. Therefore, when the bonding material 300 that is resistant to repeated temperature changes is used, the leadless component 201 may be destroyed.

For example, if solder 321 having an alloy composition that is soft and easily relieves repetitive stress is used, it is possible to prevent the leadless component 201 from being destroyed. In this case, the stress is concentrated on the solder 321 having an alloy composition that is soft and easily relieves the repetitive stress, the amount of deformation becomes large, and the joint portion 400 may be destroyed by metal fatigue due to the repetitive stress.

Further, if a conductive adhesive 323 made of a resin containing a conductive filler that easily relieves stress is used, it is possible to prevent the leadless component 201 from being destroyed, but in the case of the large leaded components 202A and 202B. Since the conductive adhesive 323 is inferior in fixing strength to the solder 321 made of a metal alloy, the joint portion 400 may be destroyed by mechanical stress such as dropping or vibration.

For example, general high-durability solder has a high content of silver, which is a precious metal, and contains an expensive metal such as indium, which is a rare earth element, and is expensive.

Further, the general conductive adhesive is more expensive because silver, which is a noble metal in the form of a filler, is mixed in at a high content.

In the embodiment of FIG. 6, the first type bonding material 301B applied by using the first metal mask 501 and the second metal mask 502 applied to the electrode pad 101 provided on the printed wiring board 100 are applied. The two-kind bonding material 302B can be coated with different materials.

Therefore, in the relationship between the parts mounted on the printed wiring board 100, the joining material 300 thereof, and the coating thickness group 410, the solder 321 having an alloy composition having a high content ratio of expensive metal and the alloy composition having a low content ratio of expensive metal. The solder 321 can be used properly, and the material cost can be reduced. Further, the solder 321 having an alloy composition having a high fixing strength and the solder 321 having an alloy composition having a high stress relaxation performance can be used properly, and the durability performance against high and low temperature repeated stress from small parts to large parts can be improved.

Further, in relation to the parts mounted on the printed wiring board 100, the joining material 300 thereof, and the coating thickness group 410, it is possible to properly use an expensive conductive adhesive and an inexpensive solder 321 to reduce the material cost. can. In addition, solder 321 with high adhesion strength and conductive adhesive 323 with stress relaxation performance can be used properly, and relaxation of small parts against high and low temperature repeated stress and maintenance of adhesion strength against mechanical stress such as dropping or vibration of large parts can be maintained. It can be compatible.

When a plurality of types of solder 321 are used for the bonding material 300, the flux 322 used for each type of solder 321 has heat resistance such as an active temperature range or a deactivation temperature of the solder 321 because it is heated and melted in one reflow process. Since it is not necessary to set each type and the same one can be used, it is easy to manage the reflow temperature setting.

Next, the bonding material coating step 710 will be described with reference to FIGS. 7 and 8.

The coating thickness group 410 is set stepwise according to the flatness of the leaded electrodes 212A and 212B of the leaded parts 202A and 202B, and the bonding material coating step 710 is the first coating thickness in the first bonding material coating process 711. The bonding material 300 is applied in the order of the second coating thickness group 412 in the group 411 and the second bonding material coating step 712, and the nth coating thickness group 41n in the nth bonding material coating step 71n.

The second metal mask 502 used for coating the second coating thickness group 412 used in the second bonding material coating step 712 is coated using the first metal mask 501 in the first bonding material coating step 711. 1 The digging portion 510 is provided with a concave digging process so as to avoid the first-class joining material 301 of the coating thickness group 411.

Further, when the squeegee 521 is used for coating in the second bonding material coating step 712, the second metal mask 502 is bent to prevent the second metal mask 502 from touching the first-class bonding material 301 applied in the first bonding material coating step 711. Therefore, the concave digging portion 510 of the second metal mask 502 is provided with a convex protrusion 511 so as to avoid the first-class joining material 301 of the first coating thickness group 411. ..

Further, the printed wiring board 100 has a convex shape provided in the recessed portion 510 of the second metal mask 502 so as to avoid the first type bonding material 301 of the first coating thickness group 411. A copper foil land 102 is provided at a position substantially corresponding to the position of the protrusion 511 of the printed wiring board 100 so as to prevent the printed wiring board 100 from sinking by the thickness of the copper foil.

Further, a solder resist 104 is provided on the surface of the copper foil land 102 to suppress the generation of conductive foreign matter generated by rubbing the convex protrusion 511 of the second metal mask 502 and the copper foil land 102. ing.

Therefore, since the bonding material 300 is applied in order from the first coating thickness group 411 according to the thickness of the bonding portion, the flatness of the leaded parts 202A and 202B can be mounted in a plurality of layers, which is a later step. Since the metal mask 500 used in the above is provided with a concave digging portion 510 that avoids the bonding material 300 applied in the previous step, the metal mask 500 starts from the first coating thickness group 411, and the second, n-. 1. The bonding material 300 can be applied in the order of the nth coating thickness group 41n, and the metal mask 500 used in a later step has a convex protrusion so as to avoid the previously applied bonding material 300. Since the 511 is provided, it is possible to prevent the metal mask 500 from coming into contact with the previously applied bonding material 300 due to the deflection of the metal mask 500 even if the concave digging is provided in a wide range, and the printed wiring board 100 has Since the copper foil land 102 is provided at a position substantially coincide with the position of the convex protrusion 511, the copper foil land 102 can prevent the metal mask 500 from sinking by the thickness of the copper foil, and the coating amount of the bonding material 300 can be prevented. Since the solder resist 104 is provided on the copper foil land 102, it is possible to prevent the copper foil land 102 and the metal mask 500 from being scraped, and it is possible to suppress the generation of metal foreign matter.

Further, in FIG. 7, the solder 321 which is the second type bonding material 302 is applied to the surface of the copper foil land 102 of the through hole 103 thicker than that of the first coating thickness group 411.

Soldering by the through-hole reflow method generally applies solder to a wider area than the land of the through-hole, and the surface tension of the solder attracts the solder to the component electrodes and the through-hole to form a joint. When solder was applied over a wider area than the lands of the through holes to form a joint, there were adverse effects on high-density mounting, such as excess solder becoming solder balls and parts not being able to be mounted around.

However, the solder 321 is applied to the surface of the copper foil land 102 of the through hole 103 thicker than that of the first coating thickness group 411, and when the leaded component 202C, which is a through hole insertion component, is joined. The amount of solder 321 required to pour into the through hole 103 can be secured without protruding the copper foil land 102 of the through hole 103 and applying the solder 321 by protruding the copper foil land 102 of the through hole 103. Since it is not necessary to apply the solder, it is possible to prevent the excess solder from becoming solder balls and remaining as conductive foreign matter, and it is possible to place other parts in close proximity, improving the component mounting density. Can be done.

Further, the solder 321 is applied so as not to enter the hole of the through hole 103, and since there is no solder 321 that enters the through hole 103, the solder 321 is inserted when the leaded electrode 212C of the leaded component 202C is inserted. Since it can be prevented from dripping and the amount required for joining can be controlled, the solder 321 in the through hole 103 can be predicted, and the soldered state is monitored by monitoring the opposite side of the through hole 103 on the solder coating side. Can be inspected.

Next, the manufacturing method of the electronic substrate unit 1 will be described with reference to FIGS. 8 and 9. The manufactured electronic board unit 1 has a rectangular shape with a built-in element, and is a leadless component 201 having a leadless electrode 211 on the surface and a lead which is two or more terminals made of metal drawn from the element. A printed wiring board 100 provided with leaded parts 202A and 202B provided with attached electrodes 212A and 212B, a bonding material 300 for heating and melting by a reflow furnace, and an electrode pad 101 to which the bonding material 300 is applied on one or both sides. A joint portion 400 formed by fixing a leadless electrode 211 and an electrode pad 101, and leaded electrodes 212A and 212B and an electrode pad 101 by a bonding material 300 is provided.

The leadless parts 201 and the parts with leads 202A and 202B have heat resistance performance equal to or higher than the upper limit of the furnace set temperature 741 of the reflow furnace, and the upper limit temperature of the furnace set temperature 741 of the reflow furnace is the temperature at which the bonding material 300 is heated and melted. It is the above temperature. In the bonding material 300 applied to the electrode pad 101, the area-converted coating thickness 600, which is the value obtained by dividing the volume of the bonding material 300 by the area of the rectangular electrode pad 101, is grouped into different thicknesses from the first to the first. A plurality of coating thickness groups 410 up to n (n is an integer of 3 or more) are provided.

In the coating thickness 401 of the bonding material 300 of the first coating thickness group 411 to which the leadless electrode 211 is fixed, the leadless component 201 having the narrowest area of the leadless electrode 211 among the plurality of leadless parts 201 is fixed. The coating thickness 401 is a ratio obtained by dividing the coating width 402 of the bonding material 300 on the short side side of the electrode pad 101 by the coating thickness 401 of the bonding material 300, and the aspect ratio is larger than 1. The coating thickness 401 of the bonding material 300 of the second coating thickness group 412 or the second coating thickness group 412 to the nth coating thickness group 41n for fixing the leads-attached electrodes 212A and 212B is a printed wiring board provided with the electrode pad 101. The coating thickness is 232A, 232B or more of the flatness of the leaded electrode, which is the degree of variation in the heights of the leaded electrodes 212A and 212B in the direction perpendicular to 100.

The relationship between the coating thickness 401 of the plurality of coating thickness groups 410 is that the first coating thickness group 411 <second coating thickness group 412 <nth coating thickness group 41n. The temperature at which the bonding material 300 is heated and melted is lower than the furnace set temperature 741 of the reflow furnace, and the bonding material 300 of the first coating thickness group 411 and the second coating thickness group 412 or the second coating thickness group 412 The joining material 300 of the nth coating thickness group 41n is made of the same kind or two or more kinds of materials.

The method for manufacturing the electronic substrate unit 1 includes a joining material coating step 710, a component mounting step 721, and a reflow step 731. The joint material application step 710 includes a first joint material application step 711, a second joint material application step 712, and an nth joint material application step 71n. The reflow step 731 includes preheating 743, main heating 744, and cooling 745. The joining material 300 is heated and melted in the main heating 744.

First, carry-in 701 for carrying the printed wiring board 100 into the apparatus for manufacturing the electronic board unit 1 is performed. Next, the first bonding material coating step 711, which is a step of applying the first type bonding material 301 with the coating thickness 401 of the first coating thickness group 411 to the electrode pad 101 to which the leadless electrode 211 of the leadless component 201 is fixed. (Step S101). The first-class bonding material 301 is applied using the first metal mask 501. Next, the second bonding material coating step 712, which is a step of applying the second type bonding material 302 with the coating thickness 401 of the second coating thickness group 412 to the electrode pad 101 to which the leaded electrode 212A of the leaded component 202A is fixed. (Step S102). The second type bonding material 302 is applied using the second metal mask 502. Next, the nth bonding material coating step 71n, which is a step of applying the nth type bonding material 30n with the coating thickness 401 of the nth coating thickness group 41n to the electrode pad 101 to which the leaded electrode 212B of the leaded component 202B is fixed. (Step S103). The type n bonding material 30n is applied using the third metal mask 503.

Next, in the step of mounting the leadless electrode 211 of the leadless component 201 and the leaded electrodes 212A and 212B of the leaded parts 202A and 202B on the bonding material 300 provided on the electrode pad 101 to which each is fixed. A certain component mounting step 721 is performed (step S104). Next, the bonding material 300 is heated and melted by one reflow heating in the reflow furnace, and the leadless electrode 211 and the electrode pad 101, and the leaded electrodes 212A and 212B and the electrode pad 101 are fixed by the melted bonding material 300. The reflow step 731, which is a step of forming the joint portion 400 to be formed, is performed (step S105). Finally, carry-out 751 is performed to carry out the electronic board unit 1 from the apparatus for manufacturing the electronic board unit 1.

The joining material 300 is, for example, a solder made of a metal alloy, which is a first-class joining material 301A of the first coating thickness group 411, which is one coating thickness group, and a second coating thickness group 412, which is the other coating thickness group. As shown in FIG. 5, the particle size of the solder 321 may be different from that of the type 2 bonding material 302A. Further, the bonding material 300 is, for example, a solder made of a metal alloy, and the first type bonding material 301B of the first coating thickness group 411, which is one coating thickness group, and the second coating thickness group, which is the other coating thickness group. As shown in FIG. 6, the alloy composition of the solder 321 may be different from that of the second-class joining material 302B of 412. Further, as shown in FIG. 10, the first-class bonding material 301 of the first coating thickness group 411 is a conductive adhesive 323 made of a resin containing a conductive filler, and is the second of the second coating thickness group 412. The seed bonding material 302A may be a solder 321 made of a metal alloy.

As shown in FIG. 7, the second metal mask 502 used for coating the bonding material 300 in the second bonding material coating step 712 is an electrode pad 101 to which the leadless electrode 211 is fixed in the first bonding material coating process 711. It has a digging portion 510 provided so as to surround the first-class joining material 301 applied to the above. At the bottom of the dug portion 510 of the second metal mask 502, an electrode pad 101 provided with a first-class bonding material 301 of the first coating thickness group 411 and a first-class bonding material 301 of the first coating thickness group 411 are provided. A protrusion 511 is provided in contact with the portion of the printed wiring board 100 between the provided electrode pad 101. Further, a copper foil land 102 is provided at a portion of the printed wiring board 100 in contact with the protrusion 511. Further, the solder resist 104 is provided on the copper foil land 102.

The printed wiring board 100 may be provided with a through hole 103, and a copper foil land 102 may be provided on the surface portion of the printed wiring board 100 surrounding the through hole 103. In the second bonding material coating step 712, the solder 321 made of a metal alloy which is the second type bonding material 302 of the coating thickness 401 of the second coating thickness group 412 is applied to the copper foil land 105, and in the component mounting process 721, the lead is used. The leaded electrode 212C of the attached component 202C is inserted into the through hole 103 to mount the leaded component 202C. The solder 321 is applied to the surface of the copper foil land 105, avoiding the portion of the through hole 103.

(2) Key points and features of the embodiment According to claim 1 and claim 8 of the present invention, the electronic board unit 1 is a leadless component having a reflow heat resistance performance of 240 having a reflow furnace set temperature of 741 or higher. The volume of 201, the parts with leads 202A and 202B, the printed wiring board 100 provided with the electrode pad 101, and the bonding material 300 applied to the printed wiring board 100 according to the mounted component is divided by the area of the electrode pad 101. A joint portion 400 composed of a first coating thickness group 411 and a second coating thickness group 412 or a second coating thickness group 412 to an nth coating thickness group 41n in which the coating thickness 401, which is a value, substantially coincides with each other, and a reflow furnace. A bonding material 300 made of the same type or two or more types that is heated and melted at a furnace set temperature of less than 741 is provided.

Therefore, mounting components equipped with terminals having different terminal shapes or flatness accuracy can be mounted on the same mounting surface and fixed by one reflow heating, which eliminates the need for a process of reducing the number of reflows and compensating for a shortage of joint materials, resulting in productivity. Has the effect of improving. In addition, it has the effect of reducing thermal stress on the mounted components and the printed wiring board. It also has the effect of reducing the failure rate of mounted components and printed wiring boards.

According to claims 2 and 9 , the bonding material 300 of the first coating thickness group 411 of the coating thickness group 410 and the second coating thickness group 412 or the second coating thickness group 412 of the coating thickness group 410 The bonding material 300 of the nth coating thickness group 41n is a solder made of a metal alloy, and is composed of two or more kinds of pre-dissolution particle diameters according to the coating thickness group 410. The bonding material 300 is composed of solder 321 having two or more kinds of pre-melting particle diameters of the metal alloy.

Therefore, when the coating thickness is thin and the coating area is narrow, small-diameter solder can be used, so that there is an effect that coating can be performed with high filling efficiency. Further, when the coating thickness is thick and the coating area is large, a large-diameter solder can be used, so that there is an effect that the coating can be performed in a stable coating shape.

According to claims 3 and 10 , of the present invention, the bonding material 300 of the first coating thickness group 411 of the coating thickness group 410 and the second coating thickness group 412 or the second coating thickness group 412 of the coating thickness group 410. The joining material 300 of the nth coating thickness group 41n is a solder made of a metal alloy, and the joining material 300 is composed of solder 321 having two or more kinds of compositions in relation to the mounted component and the coating thickness group 410. ..

Therefore, it is possible to properly use the solder having an alloy composition having a high noble metal content and the solder having an alloy composition having a low noble metal content, which has the effect of reducing the material cost. Further, it is possible to properly use an alloy composition having a high fixing strength and a solder having a high stress relaxation performance, and there is an effect that the durability performance against high and low temperature repeated stress from small parts to large parts can be improved.

According to claims 4 and 11 , of the present invention, the bonding material 300 of the first coating thickness group 411 of the coating thickness group 410 is a conductive adhesive 323 according to the mounted component, and the second coating of the coating thickness group 410 is used. The bonding material 300 of the thickness group 412 or the second coating thickness group 412 to the nth coating thickness group 41n is composed of a solder 321 made of a metal alloy.

Therefore, it is possible to properly use an expensive conductive adhesive and an inexpensive solder, and there is an effect that the amount of the expensive conductive adhesive used can be reduced.

According to claims 5 and 12 , even if there are a plurality of types of solder 321, the same flux 322 mixed with the solder 321 is used.

Therefore, since a flux having the same heat resistance can be used for solder having a low melting point and solder having a high melting point, there is an effect that the solder can be heated and melted by setting the reflow temperature according to the solder having a high melting point.

According to claim 13, the joining material 300 is applied in order from the first coating thickness group 411 according to the thickness of the joining portion.

Therefore, there is an effect that the flatness of the leaded component can be mounted in a plurality of layers.

According to claim 14 , the metal mask 500 is provided with a concave digging portion 510 that avoids the joining material 300 applied in the previous step.

Therefore, the joining material can be applied in the order of the first coating thickness group, the second n-1, and the nth coating thickness group, and there is an effect that the component can be mounted after all the coating steps. Further, since the coating of the joining material and the component mounting are not repeated, it is not necessary to avoid the components in the previous mounting process, which has the effect of enabling high-density mounting. Further, since the application of the joining material and the mounting of the parts are not repeated, the coating thickness of the joining material does not exceed the height of the parts in the previous mounting process, and there is an effect of preventing the amount of the joining material from being used.

According to claim 15 , the metal mask 500 is provided with a convex protrusion 511 so as to avoid the previously applied bonding material 300.

Therefore, even if there is a concave digging portion in a wide range, there is an effect of preventing the metal mask from coming into contact with the previously applied joint material due to the deflection of the metal mask when the joint material is applied.

According to claim 16 , the printed wiring board 100 is provided with a copper foil land 102 at a position substantially coincide with the position of the convex protrusion 511.

Therefore, the copper foil land has the effect of preventing the metal mask from sinking by the thickness of the copper foil and reducing the error in the coating amount of the joining material.

According to claim 17 of the present invention, the copper foil land 102 is provided with a solder resist 104.

Therefore, it is possible to prevent the copper foil land from being scraped, and it is effective in suppressing the generation of metal foreign matter.

According to claims 6 and 18 , the solder 321 is applied to the surface of the copper foil land 102 of the through hole 103 thicker than that of the first coating thickness group 411.

Therefore, there is an effect that the amount of solder required for pouring into the through hole when joining the lead-attached parts, which are the through hole insertion parts, can be secured without sticking out the copper foil land of the through hole and applying the solder. be. Further, since it is not necessary to apply the solder by sticking out of the copper foil land of the through hole, there is an effect of preventing the excess solder from becoming a solder ball and remaining as a conductive foreign substance. Further, it becomes possible to arrange other parts in close proximity to each other, which has the effect of improving the component mounting density.

According to claims 7 and 19 of the present invention, the solder 321 is applied so as not to enter the holes of the through holes 103.

Therefore, since there is no solder that enters the through hole, there is an effect of preventing the solder from dripping when the terminal is inserted. Further, since the coating amount can be quantified, the solder in the through hole can be predicted, and there is an effect that the soldering state can be inspected by monitoring the opposite surface on the coating side.

Also, although various exemplary embodiments are described in the present application, the various features, embodiments, and functions described in one embodiment are not limited to the application of a particular embodiment. It can be applied alone or in various combinations.
Therefore, innumerable variations not exemplified are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

1 Electronic board unit, 100 printed wiring board, 101 electrode pad, 102 copper foil land, 103 through hole, 104 solder resist, 105 copper foil land, 201 leadless part, 202A lead part, 202B lead part, 202C lead part Parts, 211 Leadless Electrodes, 212A Leaded Electrodes, 212B Leaded Electrodes, 212C Leaded Electrodes, 221 Leaded Parts Heat Resistant Performance, 222A Leaded Parts Heat Resistant Performance, 222B Leaded Parts Heat Resistant Performance, 231 Leadless Electrodes Flatness of 232A Leaded Electrode Flatness, 232B Flatness of Leaded Electrode, 240 Reflow Heat Resistant Performance, 300 Bonding Material, 301 Class 1 Bonding Material, 302 Class 2 Bonding Material, 30n Class n Bonding Material, 311 Melting temperature of type 1 bonding material, 312 Melting temperature of type 2 bonding material, Melting temperature of 31n type n bonding material, 321 solder, 322 flux, 323 conductive adhesive, 400 joint, 401 coating thickness, 402 coating width, 410 coating thickness group, 411 first coating thickness group, 412 second coating thickness group, 41n nth coating thickness group, 500 metal mask, 501 first metal mask, 502 second metal mask, 503rd 3 metal masks, 510 digging parts, 511 protrusions, 521 squeegees, 600 area conversion coating thickness, 701 carry-in, 710 bonding material coating process, 711 first bonding material coating process, 712 second bonding material coating process, 71n first n Bonding material coating process, 721 component mounting process, 731 reflow process, 740 reflow profile, 741 furnace set temperature, 742 furnace set temperature upper limit, 743 preheating, 744 heating, 745 cooling, 751 unloading

Claims (19)

A rectangular parallelepiped shape with a built-in element, a leadless component with a leadless electrode with electrodes directly formed on the surface, and a leadless component.
Leaded parts equipped with leaded electrodes in which two or more electrodes are formed from metal terminals drawn from the element, and
The joining material that is heated and melted by the reflow oven,
A printed wiring board with electrode pads on one or both sides,
An electronic substrate unit comprising the leadless electrode, the leaded electrode, and a joint portion formed by fixing the electrode pad with the joint material.
The leadless parts and the lead-attached parts have reflow heat resistance performance equal to or higher than the furnace set temperature upper limit of the reflow furnace.
The upper limit of the furnace set temperature of the reflow furnace is equal to or higher than the temperature at which the bonding material is heated and melted.
The joint comprises a coating thickness group grouped so that the area-equivalent coating thickness, which is the volume of the bonding material divided by the area of the electrode pad, substantially matches in stages.
The coating thickness of the first coating thickness group of the coating thickness group has an aspect ratio of more than 1, which is the ratio of the coating width of the joining material of the component having the narrowest electrode area of the leadless component divided by the coating thickness. It is a coating thickness,
The coating thickness of the second coating thickness group or the nth coating thickness group (n is an integer of 3 or more) of the coating thickness group is equal to or greater than the flatness of the lead-attached electrode.
The relationship between the coating thickness of the coating thickness group is
1st coating thickness group <2nd coating thickness group <nth coating thickness group,
Further, the joint portion comprises the joint material whose temperature at which the temperature is heated and melted by the reflow furnace is lower than the temperature set in the furnace.
The first coating thickness group and the second coating thickness group of the coating thickness group or the second coating thickness group to the nth coating thickness group of the bonding material are of the same type or two or more types.
The joint material of the coating thickness group is applied stepwise and is heated and melted by one reflow heating per one side of the printed wiring board, and the leadless component and the leaded component having the reflow heat resistance performance are one-sided or An electronic substrate unit provided with the joint portion formed by being fixed to the electrode pads provided on both sides. The first coating thickness group of the coating thickness group, the second coating thickness group of the coating thickness group, or the bonding material of the second coating thickness group to the nth coating thickness group is a solder made of a metal alloy. The electronic substrate unit according to claim 1, which has two or more kinds of pre-dissolution particle diameters. The first coating thickness group of the coating thickness group, the second coating thickness group of the coating thickness group, or the bonding material of the second coating thickness group to the nth coating thickness group is a solder made of a metal alloy. The electronic substrate unit according to claim 1 or 2, wherein the alloy composition is two or more kinds. The bonding material of the first coating thickness group of the coating thickness group is a conductive adhesive made of a resin containing a conductive filler.
The electronic substrate unit according to claim 1, wherein the bonding material of the second coating thickness group or the second coating thickness group to the nth coating thickness group of the coating thickness group is a solder made of a metal alloy. The electronic board unit according to any one of claims 2 to 4, wherein the flux used in the solder has the same component. A through hole is provided in the printed wiring board, and the printed wiring board is provided with a through hole.
The surface of the copper foil land of the through hole is coated with solder made of a metal alloy which is a joining material of the second coating thickness group of the coating thickness group or the nth coating thickness group from the second coating thickness group. The electronic board unit according to claim 1. The electronic substrate unit according to claim 6 , wherein the solder applied to the surface of the copper foil land is applied so as not to enter the holes of the through holes. A rectangular parallelepiped shape with a built-in element, a leadless component with a leadless electrode with electrodes directly formed on the surface, and a leadless component.
Leaded components with leaded electrodes, which are two or more terminals made of metal drawn from the element.
Joining material for heating and melting in a reflow oven,
A printed wiring board provided with an electrode pad to which the joining material is applied on one or both sides, and a printed wiring board.
The leadless electrode and the electrode pad, and the leaded electrode and the electrode pad are provided with a joint portion formed by the bonding material.
The leadless parts and the lead-attached parts have a heat resistance performance equal to or higher than the upper limit of the furnace set temperature of the reflow furnace.
The upper limit temperature of the furnace set temperature of the reflow furnace is a temperature equal to or higher than the temperature at which the bonding material is heated and melted.
The bonding material applied to the electrode pad is a value obtained by dividing the volume of the bonding material by the area of the electrode pad, and the area-equivalent coating thickness is grouped into different thicknesses from the first to n (n). Has multiple coating thickness groups up to 3)
The coating thickness of the bonding material of the first coating thickness group to which the leadless electrode is fixed is the electrode to which the leadless component having the narrowest area of the leadless electrode among the plurality of leadless components is fixed. The aspect ratio, which is the ratio of the coating width of the bonding material of the pad divided by the coating thickness, is a coating thickness larger than 1.
The coating thickness of the bonding material of the second coating thickness group or the second coating thickness group to the nth coating thickness group to which the lead-attached electrode is fixed is the said in the direction perpendicular to the printed wiring board provided with the electrode pad. The coating thickness is equal to or greater than the flatness of the leaded electrode, which is the degree of variation in the height of the leaded electrode.
The relationship between the coating thicknesses of the plurality of coating thickness groups is as follows.
1st coating thickness group <2nd coating thickness group <nth coating thickness group,
The temperature at which the bonding material is heated and melted is lower than the furnace set temperature of the reflow furnace.
The joining material of the first coating thickness group and the joining material of the second coating thickness group or the second coating thickness group to the nth coating thickness group are electronic substrate units made of the same type or two or more kinds of materials. It is a manufacturing method of
A step of applying the bonding material to the electrode pad to which the leadless electrode of the leadless component is fixed with the coating thickness of the first coating thickness group.
A step of applying the bonding material to the electrode pad to which the lead-attached electrode of the lead-attached component is fixed with the coating thickness of the second coating thickness group.
A step of applying the bonding material to the electrode pad to which the lead-attached electrode of the lead-attached component is fixed with the coating thickness of the nth coating thickness group.
A step of mounting the leadless electrode of the leadless component and the leaded electrode of the leaded component on the bonding material provided on the electrode pad to which each is fixed.
In the reflow furnace, the bonding material is heated and melted by one reflow heating per one side of the printed wiring board, and the leadless electrode and the electrode pad, and the leaded electrode and the electrode pad are melted. A method for manufacturing an electronic substrate unit, comprising a step of forming a joint portion to be fixed by a material. The joining material is a solder made of a metal alloy.
The method for manufacturing an electronic substrate unit according to claim 8 , wherein the bonding material of one coating thickness group and the bonding material of the other coating thickness group have different particle diameters of the solder. The joining material is a solder made of a metal alloy.
The method for manufacturing an electronic substrate unit according to claim 8 or 9 , wherein the bonding material of one coating thickness group and the bonding material of the other coating thickness group have different alloy compositions of the solder. The joining material of the first coating thickness group is a conductive adhesive made of a resin containing a conductive filler.
The method for manufacturing an electronic substrate unit according to claim 8 , wherein the joining material of the second coating thickness group or the joining material of the second coating thickness group to the nth coating thickness group is a solder made of a metal alloy. .. The method for manufacturing an electronic board unit according to any one of claims 9 to 11 , wherein the flux used in the solder has the same component. The one according to any one of claims 8 to 11, wherein the first coating thickness group is first applied to the bonding material, and the second, n-1, and n are applied in this order. How to manufacture an electronic board unit. In the step of applying the bonding material at the coating thickness of the second coating thickness group and the step of applying the bonding material at the coating thickness of the nth coating thickness group, the metal mask used for coating the bonding material is first described. The method for manufacturing an electronic substrate unit according to claim 8 , further comprising a digging portion provided so as to surround the joining material applied to the electrode pad to which the leadless electrode is fixed. Between the electrode pad provided with the bonding material of the first coating thickness group and the electrode pad provided with the bonding material of the first coating thickness group at the bottom of the dug portion of the metal mask. The method for manufacturing an electronic circuit board unit according to claim 14 , wherein a protrusion in contact with the portion of the printed wiring board is provided. The method for manufacturing an electronic circuit board unit according to claim 15 , wherein a copper foil land is provided on a portion of the printed wiring board in contact with the protrusion. The method for manufacturing an electronic substrate unit according to claim 16 , wherein a solder resist is provided on the copper foil land. The printed wiring board has a through hole and has a through hole.
A copper foil land is provided on the surface portion of the printed wiring board that surrounds the through hole.
The step of applying the bonding material to the electrode pad to which the lead-attached electrode of the lead-attached component is fixed with the coating thickness of the second coating thickness group, or the lead-attached electrode of the lead-attached component is fixed. In the step of applying the bonding material to the electrode pad with the coating thickness of the nth coating thickness group, the bonding material having the coating thickness of the second coating thickness group or the bonding material having the coating thickness of the nth coating thickness group is used. A solder made of a certain metal alloy is applied to the copper foil land, and the solder is applied.
In the step of mounting the leadless electrode of the leadless component and the leaded electrode of the leaded component on the bonding material provided on the electrode pad to which each is fixed, the leaded component is said to have the leaded component. The method for manufacturing an electronic board unit according to claim 8 , wherein an electrode with a lead is inserted into the through hole to mount the component with a lead. The method for manufacturing an electronic board unit according to claim 18 , wherein the solder is applied to the surface of the copper foil land while avoiding the portion of the through hole.

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