JP2010212616A - Electrode pad and method of manufacturing the same, circuit wiring and method of manufacturing the same, and soldered joint structure and soldering method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode pad which is formed by curing conductive paste and can be connected by solder, and a method of manufacturing the pad, to provide a circuit wiring and a method of manufacturing the same, and to provide a soldered joint structure and a soldering method thereof. <P>SOLUTION: The electrode pad 10 has a resin and a metal filler contained in the resin. The metal filler includes a first filler group 21A formed by lamination of a plurality of first fillers 21, and a second filler group 22A layered on the first filler group 21A and formed by lamination of a plurality of second fillers 22 having an average grain diameter value larger than that of the first fillers 21, with at least part of the second fillers 22 being exposed from a surface 12a of the resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrode pad formed by curing a conductive paste and a manufacturing method thereof, a circuit wiring body including the electrode pad and a manufacturing method thereof, a solder joint structure using the electrode pad, and a method thereof.

  Conventionally, wiring used for a semiconductor package or the like is generally formed using a photolithography method. This wiring structure and wiring forming method will be described in detail with reference to FIG.

  As shown in FIG. 14A, a chip electrode 101 connected to an internal circuit is provided on the main surface of the LSI chip 100, and a part of the chip electrode 101 is exposed on the chip electrode 101 to provide a first insulation. Resin 102 is formed. Then, a copper film 103 serving as a base of the wiring layer is formed on the first insulating resin 102 by sputtering or the like. Subsequently, as shown in FIG. 14B, a photosensitive resin 104 for forming an etching resist is applied using a spin coater or the like. Thereafter, as shown in FIG. 14C, the pattern forming portion is exposed and developed using a photomask 105. Thereby, as shown in FIG. 14D, the photosensitive resin 104 is divided into an unexposed portion 104a and an exposed portion 104b.

Subsequently, as shown in FIG. 14E, the resin of the unexposed portion 104a other than the developing portion is removed to form an etching resist. And as shown in FIG.14 (f), the copper wiring 106 used as a wiring pattern is formed by removing copper other than a wiring part by an etching. Thereafter, as shown in FIG. 14G, the copper wiring 106 is completed by removing the etching resist formed of the exposed portion 104b.
As a wiring forming method using a photolithography method, various methods other than the method described above are disclosed (for example, refer to Patent Document 1).

  However, in the wiring formation method using these photolithography methods, it is necessary to remove all copper other than the wiring in the manufacturing process, and from the viewpoint of environmental protection due to the fact that the used etching liquid becomes a waste liquid, A different method was desired. In addition, as described above, there are problems such as a large amount of initial equipment investment due to the need for complicated processes and an inevitable increase in cost due to the need for many manufacturing processes.

  On the other hand, in recent years, a technique of using a conductive paste containing a conductive filler in a resin for a conductive portion of a wiring board has been proposed (see, for example, Patent Document 2), which replaces a wiring technique based on a photolithography method. Attention has been paid.

JP 2003-174118 A JP 2005-71825 A

However, when the wiring using the conductive paste as in Patent Document 2 is used, there is a problem that soldering cannot be performed. 15 and 16 show a state in which an electrode pad 111 is formed by curing a conductive paste made of a resin 112 and a metal filler 113 on a substrate 110, and solder 114 is soldered to the electrode pad 111. Yes.
That is, as shown in FIG. 15, the metal filler 113 constituting the cured conductive paste that forms the electrode pad 111 is covered with the coating 112 a made of the resin 112 formed on the surface. For this reason, even if soldering is performed, solder non-wetting 115 occurs due to the coating 112a, and soldering cannot be performed. In addition, as shown in FIG. 16, when this coating 112a is removed and a part of the metal filler 113 in the conductive paste is exposed, the conductive filler usable for wiring has a particle size of the metal filler. The metal filler 113 is dissolved and diffused in the molten solder at the time of soldering, and the void 116 is generated, so that the soldering cannot be performed.

  The present invention has been made in view of the above-described circumstances, and is formed by curing a conductive paste, and can be connected to a solderable electrode pad, a manufacturing method thereof, a circuit wiring body, a manufacturing method thereof, and A solder joint structure and a method thereof are provided.

In order to solve the above problems, the present invention proposes the following means.
The present invention is an electrode pad having a resin and a metal filler contained in the resin, wherein the metal filler includes a first filler group configured in layers by a plurality of first fillers, and the first filler A second filler group that is laminated on the filler group and configured in layers by a plurality of second fillers having a particle size average value larger than that of the first filler, and at least a part of the second filler Is exposed from the surface of the resin.

  The present invention is also a method for producing an electrode pad having a resin and a metal filler contained in the resin, wherein the first resin includes a plurality of first fillers as the metal filler as a conductive paste. And a second paste comprising a plurality of second fillers that are the metal filler and have an average particle diameter larger than that of the first filler. A first conductive layer 11 forming step for forming the first conductive layer 11 on the substrate by the first paste, and a second paste on the first layer for forming the first conductive layer 11 on the surface. And a second conductive layer forming step of forming a second conductive layer so that the second filler is exposed.

  According to the present invention, since the second filler is exposed from the surface of the resin, solder non-wetting does not occur due to film formation by the resin. In addition, since the second filler to be soldered located on the upper side has a larger average particle size than the first filler, the second filler is melted and diffused during soldering to form voids. Will not occur. For this reason, it is possible to reliably perform solder connection with the second filler while maintaining good conduction as the electrode pad with the first filler.

1A is a plan view of a circuit wiring body according to a first embodiment of the present invention, and FIG. 2B is a cross-sectional view taken along line AA in FIG. It is sectional drawing which shows the state which soldered to the electrode pad of the 1st circuit wiring body of this invention. It is explanatory drawing explaining the 1st printing process and 1st hardening process of a 1st conductor layer formation process in the manufacturing method of the circuit wiring body of the 1st Embodiment of this invention. It is explanatory drawing explaining the 1st resin removal process of the 1st conductor layer formation process in the manufacturing method of the circuit wiring body of the 1st Embodiment of this invention. It is explanatory drawing explaining the 2nd printing process of the 2nd conductor layer formation process in the manufacturing method of the circuit wiring body of the 1st Embodiment of this invention. It is explanatory drawing explaining the 2nd hardening process of the 2nd conductor layer formation process in the manufacturing method of the circuit wiring body of the 1st Embodiment of this invention. It is explanatory drawing explaining the 2nd resin removal process of the 2nd conductor layer formation process in the manufacturing method of the circuit wiring body of the 1st Embodiment of this invention. It is (a) top view of the circuit wiring body of the 3rd Embodiment of this invention, and sectional drawing in cutting | disconnection line AA in (b) (a). It is sectional drawing which shows the state which soldered to the electrode pad of the 3rd circuit wiring body of this invention. It is explanatory drawing explaining the 1st printing process and 1st hardening process of a 1st conductor layer formation process in the manufacturing method of the circuit wiring body of the 3rd Embodiment of this invention. It is explanatory drawing explaining the 2nd printing process of the 2nd conductor layer formation process in the manufacturing method of the circuit wiring body of the 3rd Embodiment of this invention. It is explanatory drawing explaining the 2nd hardening process of the 2nd conductor layer formation process in the manufacturing method of the circuit wiring body of the 3rd Embodiment of this invention. It is explanatory drawing explaining the 2nd resin removal process of the 2nd conductor layer formation process in the manufacturing method of the circuit wiring body of the 3rd Embodiment of this invention. It is explanatory drawing explaining the method by the photolithographic method in the manufacturing method of the conventional circuit wiring body. It is sectional drawing in the cutting line BB of (a) top view of the circuit wiring body using the conventional electrically conductive paste, (b) (a). It is explanatory drawing explaining the solder connection state of the circuit wiring body using the conventional electrically conductive paste.

Embodiments according to the present invention will be described with reference to FIGS. As shown in FIG. 1 and FIG. 2, the circuit wiring body 1 of the present embodiment is connected to the substrate 2, the wiring portion 3 disposed on the substrate 2, and the wiring portion 3 provided on the substrate 2. The electrode pad 10 is provided. The board | substrate 2 is comprised from the base material 2b by which the base-side wiring 2a was formed in the surface, and the insulating material 2c laminated | stacked on the base material 2b. In addition, as long as the base material side wiring 2a etc. are not provided and the outermost surface of the base material 2b has insulation, it is good also as a structure which does not provide the insulating material 2c.
Further, on the substrate 2b, the substrate-side electrode pad 2d is connected to the substrate-side wiring 2a, and the substrate-side electrode pad 2d is insulated from the opening 2e provided corresponding to the insulating material 2c. It is connected to the wiring part 3 provided on 2c. Moreover, the wiring part 3 and the electrode pad 10 are formed by curing a conductive paste having a resin and a metal filler contained in the resin, respectively.

  Here, the electrode pad 10 is laminated on the base material 2b, and includes a first conductive layer 11 having a first filler group 21A configured in layers by a plurality of first fillers 21 as a metal filler, The second filler group 22A is laminated on the conductive layer 11 and is configured in layers by a plurality of second fillers 22 as metal fillers, and the second fillers 22 are exposed from the surface 12a which is the outermost surface. The second conductive layer 12 is provided. In the present embodiment, the electrode pad 10 is formed in a substantially circular shape. However, the present invention is not limited to this, and the wiring portion 3 has the same width as the wiring portion 3 when it is necessary to form a rectangular shape or a narrow pitch. The tip of the electrode pad 10 may be used as the electrode pad 10. Then, as shown in FIG. 2, solder 4 is soldered to the surface 12 a of the electrode pad 10.

  The first conductive layer 11 is formed by curing a first paste 24 having a first resin 23 and a first filler 21 contained in the first resin 23 as a conductive paste. In the present embodiment, the wiring portion 3 is similarly formed by curing the first paste 24 as a conductive paste. Here, as the first conductive layer 11, the first filler 21 is formed from the first resin 23 on the surface of the first conductive layer 11, that is, at the boundary with the second conductive layer 12. It is desirable that the first filler 21 is included so as to be exposed to the second resin 25 side.

  The second conductive layer 12 is formed by curing a second paste 25 having a second resin 25 and a second filler 22 contained in the second resin 25 as a conductive paste. As shown, a part of the second filler 22 close to the surface 12a is exposed. Here, the exposure from the surface 12a of the second filler 22 does not necessarily need to be in a completely exposed state, and at least obstructs soldering by the manufacturing method according to the present invention including the embodiments described later. It also includes those covered with an extremely thin thin film that does not have any. In addition, the second filler 22 of the second conductive layer 12 has a contact portion 27 in contact with the first filler 21 exposed from the first resin 23 at the boundary with the first conductive layer 11 as described above. It is desirable that it be formed. Moreover, it does not specifically limit as each material of the 1st resin 23 of the 1st conductive layer 11, and the 2nd resin 25 of the 2nd conductive layer 12, It is good also as the same material.

  From the viewpoint of increasing the printability and the content of the metal filler in the conductive paste to lower the resistance value, the first filler 21 is set to have a particle size sufficiently small with respect to the wiring width. The filler 22 is set to have a sufficiently large particle size from the viewpoint of suppressing dissolution in the solder, and the average particle size of the second filler 22 is larger than the average particle size of the first filler 21. Is set to More specifically, the first filler 21 desirably has a particle size peak of 5 nm to 5 μm in particle size, and more preferably 0.1 μm to 1 μm in particle size. The first filler 21 may have two or more particle size peaks. In this case, each of the particle size ranges from 0.1 μm to 1 μm and the particle size ranges from 30 nm or less. It is further desirable to have a particle size peak. Thereby, especially the content rate of the metal filler in an electrically conductive paste can be raised. Furthermore, the metal fine particles having a particle size of about 30 nm or less have a property of being fused at a low temperature, and by containing such metal fine particles, the first fillers 21 are fused to each other to form the first filler. It is possible to realize an improvement in electrical conductivity between 21. On the other hand, the second filler 22 preferably has a particle size peak of 0.5 μm or more and 20 μm or less in particle size, and more preferably 1 μm or more and 20 μm or less in particle size. Further, the second filler 22 may have two or more particle size peaks within this particle size range.

  Further, the shape of the first filler 21 is not particularly limited, but it is preferably a flake shape, a spherical shape, or a combination thereof. By making the first filler 21 into flakes, the filling property of the conductive filler can be increased and the content of the metal filler in the conductive paste can be increased, and the contact area between the metal fillers can be increased. Contact resistance can be reduced. Moreover, the fluidity | liquidity as an electrically conductive paste is made favorable, and printability can be improved by making a 1st filler into spherical powder. On the other hand, the shape of the second filler 22 is not particularly limited, but it is preferable to contain spherical powder, and it is desirable to include spherical powder even when other shapes such as flakes are used. Spherical powder can increase the minimum distance from the surface of the metal filler to the center compared to other shapes. Exposure from the surface of the layer 12 is facilitated.

  The material of the first filler 21 is not limited as long as the printability and conductivity required for wiring can be secured, but silver, gold, copper, copper alloy, nickel, nickel alloy, palladium, or copper, It is desirable to consist of any one or a combination of copper alloy, nickel or nickel alloy coated with silver. On the other hand, the material of the second filler 22 is not particularly limited as long as it can be joined to solder and can be electrically connected, but, like the first filler 21, silver, gold, copper, copper alloy, nickel, nickel It is desirable to be made of alloy, palladium, or any one or a combination of copper, copper alloy, nickel, or nickel alloy coated with silver.

Next, details of the electrode pad 10, the method of manufacturing the circuit wiring body 1, and the method of soldering to the electrode pad 10 of this embodiment will be described.
First, as a preparation step, the substrate 2 is prepared, and the first paste 24 and the second paste 26 that are conductive pastes for forming the first conductive layer 11 and the second conductive layer 12 are prepared. First, the substrate 2 is formed by laminating the insulating material 2c on the surface of the base material 2b on which the base material side wiring 2a is formed. Here, in the subsequent wiring portion forming step, in order to connect the wiring portion 3 and the substrate-side electrode pad 2d, the insulating material 2c is laminated so as to exclude the portion of the substrate-side electrode pad 2d. In addition, as above-mentioned, when the outermost surface of the base material 2b has insulation, it is not necessary to laminate | stack the insulating material 2c. The first paste 24 and the second paste 26 are prepared by adding a predetermined amount of the first filler 21 or the second filler 22 to the paste-like first resin 23 or the second resin 25, respectively. Manufactured by mixing.

  Next, a wiring portion forming step for forming the wiring portion 3, a first conductive layer forming step for forming the first conductive layer 11 and the second conductive layer 12 of the electrode pad 10, and a second conductive layer, respectively. A layer forming step is performed. Here, in the present embodiment, the first conductive layer 11 formed on the substrate 2 below the electrode pad 10 and the wiring portion 3 are both formed of the first paste 24, so that Can be implemented. Note that it is not always necessary to perform them simultaneously, and the wiring portion forming step and the first conductive layer forming step may be performed independently of each other.

  That is, as shown in FIG. 3, in the wiring portion forming step and the first conductive layer forming step, first, as the first printing step, the first conductive layer 11 of the wiring portion 3 and the electrode pad 10 on the substrate 2. The first paste 24 prepared in the preparation process is printed in the range. A specific printing method is not particularly limited, and a screen printing method, a dispensing method, an ink jet method, a relief printing method, an intaglio printing method, or an offset printing method thereof can be used. Then, as the first curing step, the first paste 24 printed in this way is cured. Next, as a first resin removing step, the first resin 23 constituting the hardened first paste 24 is removed from the surface 11a of the first conductive layer 11 of the electrode pad 10, thereby obtaining FIG. As shown, the first filler 21 existing in the vicinity of the surface 11a can be exposed. A specific removal method is not particularly limited as long as it does not reduce the adhesion of the first conductive layer 11 to the substrate 2 or the electrical characteristics of the first conductive layer 11, but plasma treatment, A mechanical grinding method, a chemical mechanical polishing method (CMP), or the like can be suitably used.

  Next, as the second conductive layer forming step, the second conductive layer 12 is formed on the surface 11 a of the first conductive layer 11. That is, first, as shown in FIG. 5, as the second printing step, the second paste 26 is printed on the cured first paste 24 in a range that becomes the second conductive layer 12. Although it does not specifically limit as a concrete printing method, Printing is possible by the method similar to a 1st printing process. Here, since the first paste 24 forming the first conductive layer 11 serving as the lower layer is cured in advance, the first conductive layer 11 is formed even when the second paste 26 is printed in an overlapping manner. The shape of the first paste 24 does not collapse, and both are not mixed.

  Next, as shown in FIG. 6, the second paste 26 printed in this way is cured as a curing step. At this time, the viscosity of the second resin 25 gradually decreases, and the second filler group 22A settles relative to the second resin 25 on the first conductive layer 11, thereby A contact portion 27 in which the first filler 21 and the second filler 22 exposed from the first resin 23 are in contact with each other can be formed.

Next, as shown in FIG. 7, as the second resin removing step, the second resin 25 constituting the cured second paste 26 is removed from the surface of the second conductive layer 12 of the electrode pad 10. As a result, the second filler 22 existing in the vicinity of the surface 12a is exposed. Specifically, it is the same as the first resin removal step, and plasma treatment, mechanical grinding, chemical mechanical polishing (CMP), and the like can be suitably used. There is no particular limitation as long as the adhesion of the second conductive layer 12 to the first conductive layer 11 and the electrical characteristics of the second conductive layer 12 are not deteriorated, but plasma treatment, mechanical grinding method are not limited. Chemical mechanical polishing (CMP) or the like can be preferably used.
As described above, the electrode pad 10 is manufactured and the circuit wiring body 1 including the electrode pad 10 is manufactured.

  Next, as a soldering step, solder 4 is soldered to the electrode pads 10 as shown in FIG. In addition, it does not specifically limit as a soldering method, A general soldering method is applicable. At this time, the second filler 22 is exposed on the surface 12a of the second conductive layer 12 which is the surface of the electrode pad 10, so that solder non-wetting does not occur due to the film formation by the resin. . In addition, the second filler 22 to be soldered located on the upper side has a larger average particle size than the first filler 21, so that the second filler 22 melts and diffuses during soldering. As a result, voids are not generated. For this reason, it is possible to reliably perform solder connection with the second filler 22 while maintaining good conduction as the electrode pad 10 with the first filler 21.

  As described above, in the present embodiment, the second filler 22 is exposed from the resin surface and the particle size thereof, and the conductive property that cannot be realized by the conventional wiring print formation using the conductive paste. Direct soldering to the paste becomes possible. On the other hand, by setting the first filler 21 located below the second filler group 22 </ b> A to an average particle size smaller than that of the second filler 22, the filling rate of the metal filler is increased and the content rate is increased. The resistance value as the electrode pad 10 can be reduced and the conduction can be improved. For this reason, it is possible to easily achieve both the solderability in the conductive paste wiring and the formation of the fine wiring, which has been difficult in the past. Further, the first filler 21 is exposed from the first resin 23 to the second resin 25 side, and the contact portion 27 is formed between the first filler 21 and the second filler 22, thereby further reducing the resistance value and conducting. Can be made good. Moreover, in this embodiment, the wiring part 3 is formed by curing the first paste 24 in the same manner as the first conductive layer 11 of the electrode pad 10, so that the first conductive of the wiring part 3 and the electrode pad 10 is formed. The layer 11 can be formed at the same time, and the process can be shortened.

  Moreover, in this embodiment, after hardening the 1st paste 24 which forms the 1st conductive layer 11 at a 1st conductive layer formation process, it is the 2nd conductive layer 12 at a 2nd conductive layer formation process. By printing and curing the second paste 26 that forms the first paste 23, the first resin 23 of the first paste 24 and the second resin 25 of the second paste 26 are not mixed together. A boundary between the first conductive layer 11 and the second conductive layer 12 is formed. For this reason, when the first resin 23 and the second resin 25 are selected to be different materials, the base material 2b has a low affinity with each other, for example, like an epoxy resin and a silicone resin, and the two are mixed. In the case where the adhesive force with the first conductive layer 11 is reduced or the reliability is lowered, the first resin 23 included in the first conductive layer 11 has characteristics suitable for preventing such a problem. It is possible to select a material having a suitable characteristic for the second resin 25 contained in the second conductive layer 12 and to satisfy both characteristics. Properties suitable as the first resin 23 include adhesion to the substrate 2 and ease of printing. By making the adhesion good, it is possible to realize a strong and reliable circuit wiring body, By making it easy, fine wiring can be formed, and a circuit wiring body having fine wiring can be realized. Further, characteristics suitable as the second resin 25 are difficulty in inhibiting solder wetting and retention characteristics of a metal filler, which can improve solder joint strength.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. Here, in the second embodiment, only the manufacturing method is different from that of the first embodiment, and the basic structure of the circuit wiring body 1 including the electrode pad 10 and the electrode pad 10 is the same. Description will be made with reference to FIGS.

  In the present embodiment, first, when preparing the second paste 26 in the preparation step, the second resin 22 is set so that the volume ratio of the second filler 22 to the second resin 25 is higher. The second filler 22 is added to 25 and mixed. The substrate 2 and the first paste 24 are the same as those in the first embodiment.

  As shown in FIGS. 3 and 4, in this embodiment as well, the wiring portion forming step and the first conductive layer forming step are performed as in the first embodiment. Next, in a 2nd conductive layer formation process, as shown in FIG. 5, a 2nd printing process is implemented and a 2nd hardening process is implemented. Here, as described above, the second paste 26 is set so that the volume ratio of the second filler 22 to the second resin 25 is high, so that the second filler 22 is a second resin. Those that settle on the surface 25 but are located on the surface side are exposed from the second resin 25 on the surface 12a, resulting in the state shown in FIG. For this reason, in the second conductive layer forming step, the second filler 22 can be exposed from the surface without performing the second resin removing step as in the first embodiment, thereby shortening the step. Thus, solder connection can be made to the surface of the electrode pad 10 of the present embodiment formed by curing the conductive paste.

(Third embodiment)
Next, a third embodiment of the present invention will be described. 8 to 13 show a third embodiment of the present invention. In this embodiment, members that are the same as those used in the above-described embodiment are assigned the same reference numerals, and descriptions thereof are omitted.

  As shown in FIGS. 8 and 9, the electrode pad 31 of the circuit wiring body 30 of the present embodiment includes the first conductive layer 11 formed by curing the first paste 24 and the second paste 26. Although it is common to the first and second embodiments in that it is provided with a second conductive layer 12 formed by curing, the first conductive layer 11 and the second conductive layer 12 have a first boundary at the boundary between the first conductive layer 11 and the second conductive layer 12. This is different in that a mixed layer 32 in which the first resin 23 of the paste 24 and the second resin 25 of the second paste 26 are mixed is formed.

Next, the manufacturing method of the electrode pad 31 and the circuit wiring body 30 of this embodiment is demonstrated.
In this embodiment, the preparatory step is performed as in the first embodiment. Next, a wiring part forming step and a first conductive layer forming step are performed. Here, also in the present embodiment, the wiring portion 3 is formed by the first paste 24 for forming the first conductive layer 11, so that the wiring portion forming step and the first conductive layer forming step are simultaneously performed. can do.

  Here, as shown in FIG. 10, in the wiring portion forming step and the first conductive layer forming step, first, as a first printing step, the first paste 24 is placed in a range that becomes the wiring portion 3 and the electrode pad 31. Print. A specific printing method is the same as that in the first embodiment. Next, the first curing step is performed. Here, the printed first paste 24 is dried to be in a dry state, or preliminarily cured to be in a semi-cured state. It is possible to maintain a certain shape while maintaining a certain degree of flexibility.

Next, as a second conductive layer forming step, the second conductive layer 12 is formed on the surface of the first conductive layer 11.
That is, first, as shown in FIG. 11, as the second printing step, the second paste 26 is printed on the first paste 24 in a dry or semi-cured state within a range that becomes the second conductive layer 12. To do. A specific printing method is the same as that in the first embodiment. Here, since the first paste 24 forming the first conductive layer 11 serving as the lower layer is previously dried or semi-cured, even if the second paste 26 is printed over the first paste 24, The shape of the first paste 24 forming the conductive layer 11 does not collapse, and the both are not mixed.

  Next, as a second curing step, the dried or semi-cured first paste 24 is collectively cured together with the second paste 26 printed in this way. At this time, as shown in FIG. 12, the viscosity of the first resin 23 and the second resin 25 gradually decreases, and for example, BCA (butyl carbitol acetate) or terpineol contained in the second resin 25 is used. Of the first resin 23 in a dry state or a semi-cured state, and a part or all of the first resin 23 and the second resin 25 are mixed with each other. A mixed layer 32 mixed with each other is formed at the boundary with the second conductive layer 12 and cured. In addition, when the first resin 23 and the second resin 25 are mixed, the second filler group 22 </ b> A also tends to settle. Since the average particle size is small and the content density is high, the second filler group 22A settles on the first filler group 21A. For this reason, the upper first filler 21 and the lower A second filler 22 are in contact with each other within the mixed layer 32, or the resin existing between each other within the mixed layer 32 is minimized. As a result, electrical conduction between the first filler group 21A and the second filler group 22A can be improved.

Next, as shown in FIG. 13, as the second resin removal step, the second resin 25 constituting the cured second paste 26 is removed from the surface of the second conductive layer 12 of the electrode pad 31. As a result, the second filler 22 existing in the vicinity of the surface is exposed.
As a result, the electrode pad 31 is manufactured and the circuit wiring body 30 including the electrode pad 31 is manufactured.

  Next, as a soldering step, solder 4 is soldered to the electrode pads 31 as shown in FIG. Also in this embodiment, the soldering method is not particularly limited, and a general soldering method can be applied. At this time, as in the first embodiment, the second filler 22 is exposed on the surface of the second conductive layer 12 which is the surface of the electrode pad 31, so that the solder is not wet by the formation of the resin film. Will not occur. In addition, the second filler 22 to be soldered located on the upper side has a larger average particle size than the first filler 21, so that the second filler 22 melts and diffuses during soldering. As a result, voids are not generated. For this reason, it is possible to reliably perform solder connection with the second filler 22 while maintaining good conduction as the electrode pad 31 with the first filler 21.

  As described above, also in this embodiment, the first filler 21 and the second filler 22 can easily achieve both solderability in the conductive paste wiring and fine wiring formation, which has been difficult in the past. Further, in the mixed layer 32, the first filler 21 and the second filler 22 are in contact with each other, or the resin between them can be kept to a minimum, thereby further reducing the resistance value and conducting. It can be good.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. Here, the fourth embodiment is different from the third embodiment only in the manufacturing method, and the basic structure of the circuit wiring body 30 including the electrode pad 31 and the electrode pad 31 is the same. 11 and FIG. 13 will be described in the same manner.

  In the present embodiment, first, when preparing the first paste 24 and the second paste 26 in the preparation step, the first filler relative to the total amount of the resin by the first resin 23 and the second resin 25. Each of the first resin 23 and the second resin 25, and the first filler 21 and the second filler 22 so that the volume ratio of the total amount of the metal filler by the 21 and the second filler 22 is higher. Determine usage. And based on the determined usage-amount, the 1st paste 24 is manufactured by adding and mixing the 1st filler 21 with the 1st resin 23, and the 2nd filler is added to the 2nd resin 25 with the 2nd filler. 22 is added and mixed to produce the second paste 26. The substrate 2 is the same as that in the third embodiment.

  As shown in FIG. 10, in this embodiment as well, the wiring portion forming step and the first conductive layer forming step are performed as in the first embodiment. Next, in the second conductive layer forming step, a second printing step is performed as shown in FIG. 11, and a second curing step is performed. Here, as described above, the volume ratio of the total amount of the metal filler to the total amount of the resin is set so that the metal filler composed of the first filler 21 and the second filler 22 is the first resin. Although it settles with respect to resin which consists of 23 and the 2nd resin 25, what is located in the surface side among the 2nd fillers 22 will be exposed from the 2nd resin 25 in the surface. For this reason, as shown in FIG. 13, in the second conductive layer forming step, the second filler 22 can be exposed from the surface without performing the second resin removing step as in the third embodiment. Thus, the solder connection can be made to the surface of the electrode pad 31 of the present embodiment formed by curing the conductive paste while shortening the process.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

DESCRIPTION OF SYMBOLS 1, 30 Circuit wiring body 2 Board | substrate 3 Wiring part 4 Solder 10, 31 Electrode pad 11 1st conductive layer 11a Surface 12 2nd conductive layer 12a Surface 21 1st filler 22 2nd filler 23 1st resin 24 First paste 25 Second resin 26 Second paste 32 Mixed layer

Claims (19)

An electrode pad having a resin and a metal filler contained in the resin,
The metal filler is a first filler group configured in layers with a plurality of first fillers;
A second filler group that is laminated on the first filler group and configured in layers by a plurality of second fillers having a particle size average value larger than that of the first filler;
An electrode pad, wherein at least a part of the second filler is exposed from the surface of the resin. The electrode pad according to claim 1,
A first conductive layer having a first resin and the first filler contained in the first resin;
An electrode pad comprising: a second conductive layer laminated on the first conductive layer and having a second resin and the second filler contained in the second resin. The electrode pad according to claim 2,
An electrode pad, wherein a mixed layer in which the first resin and the second resin are mixed is formed at a boundary between the first conductive layer and the second conductive layer. The electrode pad according to claim 2,
At the boundary between the first conductive layer and the second conductive layer, the first filler is exposed from the first resin to the second resin side and contacts the second filler. An electrode pad in which a portion is formed. In the electrode pad according to any one of claims 1 to 4,
The electrode pad, wherein a volume ratio of the metal filler is higher than a volume ratio of the resin. The electrode pad according to claim 1,
The particle size peak of the first filler is set within a range of 5 nm to 5 μm, and the particle size peak of the second filler is set within a range of 0.5 μm to 20 μm. A featured electrode pad. The electrode pad according to any one of claims 1 to 6,
A circuit wiring body comprising a wiring portion connected to the electrode pad and having a resin and a metal filler contained in the resin. In the circuit wiring body according to claim 7,
In the wiring portion, the metal filler is constituted by the first filler.   A solder joint structure in which the second filler exposed from the resin surface of the electrode pad according to any one of claims 1 to 6 and solder are metal-bonded. A method for producing an electrode pad having a resin and a metal filler contained in the resin,
As the conductive paste, a first paste in which a plurality of first fillers that are the metal fillers are contained in a first resin, and the metal filler, the average particle diameter is larger than that of the first filler. A preparation step of preparing a second paste in which a plurality of large second fillers are contained in the second resin;
A first conductive layer forming step of forming the first conductive layer on the substrate by the first paste;
An electrode pad comprising: a second conductive layer forming step of forming a second conductive layer on the first layer by the second paste so that the second filler is exposed on the surface. Manufacturing method. In the manufacturing method of the electrode pad according to claim 10,
The first conductive layer forming step includes a first printing step for printing the first paste on the substrate, and a first curing step for drying or precuring the printed first paste. Have
The second conductive layer forming step includes a second printing step of printing the second paste on the first paste, and a second curing step of collectively curing the printed second paste and first paste. And a second curing step. A method for manufacturing an electrode pad, comprising: In the manufacturing method of the electrode pad according to claim 10,
The first conductive layer forming step includes a first printing step of printing the first paste on the substrate, a first curing step of curing the printed first paste, and the cured A first resin removing step of removing the first resin on the surface on which the second paste of the first paste is printed to expose the first filler;
The second conductive layer forming step includes a second printing step of printing the second paste on the first conductive layer, and a second curing step of curing the printed second paste. A method of manufacturing an electrode pad comprising: In the manufacturing method of the electrode pad according to claim 11,
In the preparatory step, the first filler and the second filler so that the volume ratio of the first filler and the second filler is higher than the volume of the first resin and the second resin. A method for producing an electrode pad, comprising preparing a second filler. In the manufacturing method of the electrode pad according to claim 12,
In the preparation step, the second filler is prepared such that the volume ratio of the second filler is higher than the volume of the second resin. In the manufacturing method of the electrode pad according to claim 11 or claim 12,
The second conductive layer forming step includes a second resin removal step of removing the second resin on the surface of the cured second paste to expose the second filler. Manufacturing method of electrode pad. In the manufacturing method of the electrode pad according to claim 12 or claim 15,
The method for producing an electrode pad is characterized in that the resin is removed by any one of plasma treatment, mechanical grinding treatment, and chemical polishing treatment.   The electrode pad is formed on the substrate by the electrode pad manufacturing method according to any one of claims 10 to 16, and is included in the resin and the resin on the substrate so as to be connected to the electrode pad. And a wiring part forming step of forming a wiring part with a conductive paste having a metal filler. In the manufacturing method of the circuit wiring body according to claim 17,
In the wiring portion forming step, the first paste is used as a conductive paste and is performed simultaneously with the first conductive layer forming step.   The electrode pad is formed on the substrate by the electrode pad manufacturing method according to any one of claims 10 to 16, and then soldered to the second filler exposed on the surface of the second conductive layer. A solder joint method, characterized by comprising:

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