JP4617978B2 - Wiring board manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a wiring board having a wiring pattern having a layered structure.

  In recent years, electronic devices such as mobile phones have been rapidly miniaturized, and along with that, semiconductor devices such as ICs and LSIs and other electronic components used in electronic devices have also been miniaturized. Yes. For this reason, wiring patterns on wiring boards on which electronic components are mounted are also required to be miniaturized and reduced in resistance, and stacked for miniaturization by high-density mounting.

  A conventional wiring pattern such as a wiring board is formed by printing a pattern made of silver paste or copper paste on a substrate by a printing method such as screen printing or intaglio printing, and firing the printed wiring pattern. Specifically, a conductive paste (organometallic paste) is filled in an intaglio formed corresponding to a wiring pattern such as a silicon wafer, and the conductive paste is dried and cured, and then cured on a glass substrate, for example. It is disclosed that a desired wiring pattern is formed by transferring the wiring pattern through a conductive resin and baking it in air at 500 ° C. (see, for example, Patent Document 1).

  However, in the intaglio printing, it is possible to form a fine wiring pattern with a width of 50 μm and a pitch of 100 μm, for example, but it is difficult to form a wiring pattern with a thickness of 5 μm or more, and there is a limit to the reduction of resistance. is there. Furthermore, since the wiring pattern is formed by baking at a high temperature of about 500 ° C., a flexible resin substrate cannot be used as a substrate on which the wiring pattern is formed.

  Therefore, as a method of forming a thick conductor pattern, a method of forming a wiring pattern on a substrate by forming a groove having a depth of 60 μm with an excimer laser on a polyimide resin substrate and using it as an intaglio (for example, patents) is disclosed. Reference 2).

  However, in any of the above methods, since the wiring pattern is formed by baking at a high temperature of 500 ° C. or higher, a flexible resin substrate cannot be used as a substrate on which the wiring pattern is formed.

  Therefore, the connection of electronic components with low heat resistance and the wiring pattern of flexible substrates with low heat resistance do not melt the metal powder (conductive filler), but are directly bonded to a binder and used as a conductive paste, for example, screen printing There is a wiring board formed by.

  However, in the wiring pattern using the conductive paste, since a resin component such as a binder is interposed between the conductive fillers, the conductive pattern is low and the wiring pattern is low compared to the wiring pattern obtained by baking the conventional solder or silver paste. Resistance was difficult. This is because the solder is conductive due to metal bonding, whereas the conductive paste is determined by the tunneling effect of the binder between the conductive fillers, dielectric breakdown, or contact between the conductive fillers. is there. Therefore, in order to improve the conductivity, a conductive paste in which the content of the conductive filler is increased and the conductivity is improved is disclosed (for example, see Patent Document 3).

  However, in general, when forming a wiring pattern with a conductive paste composed of a binder and a conductive filler on an insulating substrate, the mixing ratio of the binder and the conductive filler is optimized in order to improve the printability of the conductive paste. It is necessary to ensure liquidity. Therefore, conversely, it is difficult to maintain the shape of the printed wiring pattern. In particular, there was a break in the end face of the wiring pattern. In addition, after the wiring pattern is formed, when a curing process is performed at about 150 ° C., for example, who further expands, there is a problem that a fine wiring pattern cannot be formed.

Therefore, in order to solve the above-mentioned problems, generally, a conductive paste is mixed with an inorganic filler that exhibits a high thixotropic action so that the shape of the wiring pattern can be stably maintained even during coating. It has been known.
JP-A-4-240792 JP 7-169635 A JP-A 63-107188

  However, the wiring substrate having the wiring pattern disclosed in Patent Document 1 has a problem that a thick wiring pattern cannot be formed because the organic metal ink is formed by baking. Furthermore, since baking at a high temperature is required, there is a problem that a wiring pattern cannot be formed on a resin substrate.

  Moreover, in the wiring board having the wiring pattern disclosed in Patent Document 2, a thick wiring pattern can be formed, but there is a problem that the wiring pattern cannot be formed on the resin substrate as described above. . Further, since an expensive apparatus such as an excimer laser is required to form the groove in the resin substrate, the cost is increased.

  Furthermore, in the wiring board having the wiring pattern disclosed in Patent Document 3, an increase in the conductive filler has an effect on the reduction of the resistance of the wiring pattern, but the wiring pattern is reduced in order to reduce the relative amount of the binder. There is a problem that the adhesive force with the substrate on which the film is formed is reduced.

  The present invention has been made in order to solve the above-described conventional problems, and improves the adhesion strength with the substrate, and has a wiring pattern having a wiring pattern that is easily miniaturized and has a low resistance, and an electronic component mounting using the wiring substrate. The object is to provide bodies and methods for their production.

  In order to solve the above-described problems, a wiring board of the present invention includes a substrate and a wiring pattern formed on the substrate, and the wiring pattern is insulated from an insulating resin formed on the substrate side. Having a structure made of a conductor formed by being laminated on a conductive resin.

In the method for manufacturing a wiring board according to the present invention, the first recess and the second recess are filled with a conductor so as not to exceed the height of the first recess and the transfer mold having the second recess at the bottom of the first recess. And a process of
Filling the conductor with insulating resin up to the height of the first recess, placing the insulating resin side of the transfer mold on the substrate and heating, and peeling the transfer mold from the substrate And forming a conductive pattern corresponding to the first recess on the substrate via the insulating resin .

By this method, it is possible to realize a wiring substrate in which the adhesion between the substrate and the conductor is ensured with an insulating resin and the wiring pattern is formed with the conductor. Therefore, it is possible to manufacture a wiring board in which the conductor material can be arbitrarily selected without depending on the substrate material. In addition, since the wiring pattern can be formed on the substrate in the state of the wiring pattern filled in the first recess, the pitch can be reduced and the wiring having an arbitrary resistance by adjusting the thickness according to the shape of the first recess. Ru can be produced a wiring board on which a pattern is formed.

  The wiring board according to the present invention has a wiring structure having a laminated structure of an insulating resin and a conductor, thereby increasing the adhesion to the board with the insulating resin and also having a fine wiring pattern having higher conductivity with the conductor. There is a great effect that can be formed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is used about the same component and description is abbreviate | omitted.

(Embodiment 1)
FIG. 1A is a plan view of a wiring board according to Embodiment 1 of the present invention, and FIG. 1B is a cross-sectional view taken along line AA in FIG.

  In FIG. 1A, a wiring pattern 120 is formed on a substrate 100 such as a resin substrate. Further, as shown in FIG. 1B, the wiring pattern 120 includes an insulating resin 130 on the substrate 100 side and a conductor 140 laminated thereon. Since the wiring pattern 120 is formed by a transfer mold having a recess as shown in the following manufacturing method, it can be formed with a fine pitch, and a wiring pattern having a high aspect ratio and a uniform height is formed. be able to.

  Here, as the substrate 100, a glass epoxy substrate in which a glass cloth is impregnated with an epoxy resin, a flexible substrate such as a PET (polyethylene terephthalate) resin or a polyimide resin, or an inorganic substrate such as a ceramic can be used.

  For the insulating resin 130, for example, an adhesive containing a thermosetting resin is used. In addition, as a thermosetting resin, 1 type, or 2 or more types of mixed systems in epoxy resin, a phenol resin, a polyimide resin, a polyurethane resin, a melamine resin, a urea resin etc. are used, for example. In particular, the epoxy resin is preferable from the viewpoint of improving the viscosity of the insulating resin, the curing reactivity, and the adhesion strength with the substrate 100.

  The conductor 140 is made of, for example, a conductive resin or solder made of 75 to 95 parts by weight of a conductive filler and 5 to 25 parts by weight of a thermosetting resin. As the conductive filler of the conductive resin, for example, metal particles such as silver, copper, gold, nickel, palladium, tin, and alloy particles thereof are used. Further, as the thermosetting resin, for example, one or a mixture of two or more of epoxy resin, phenol resin, polyimide resin, polyurethane resin, melamine resin, urea resin and the like is used. In particular, a thermosetting resin of the same system as the insulating resin 130 is preferable in terms of improving the adhesion strength with the conductor 140.

  As the solder, a general solder can be used. In particular, when a resin substrate such as PET (polyethylene terephthalate) is used as the substrate 100, for example, In—Sn, Bi— with a melting point of 150 ° C. or less. It is preferable to use a low melting point solder such as lead-free solder such as Sn.

  Thereby, the adhesive force between the substrate 100 and the conductor 140 can be greatly improved by the adhesive force of the insulating resin 130. Therefore, the wiring pattern 120 does not peel from the substrate 100 even when the substrate 100 is subjected to deformation such as thermal stress, external impact or warpage, so that a highly flexible and highly reliable wiring substrate can be realized. Further, even when the conductor 140 is formed of a conductive resin, it is possible to increase the content of the conductive filler by selecting a material having a strong adhesion to the insulating resin 130, and thus the wiring pattern 120. Therefore, the wiring board having the wiring pattern 120 with low wiring resistance can be realized.

  Below, the manufacturing method of the wiring board which concerns on Embodiment 1 of this invention is demonstrated using FIG.

  FIG. 2 is a process cross-sectional view illustrating the method for manufacturing the wiring board according to the first embodiment of the present invention.

  First, as shown in FIG. 2A, a transfer mold 150 having a recess 160 corresponding to a position where a wiring pattern is formed is prepared. Here, as the transfer mold 150, for example, a transfer resin having a low elastic modulus and a high releasability, which is made of a thermosetting silicone resin or the like, is used. The reason for this is that, since it is a silicone resin, it is excellent in releasability from conductive resin and solder. Second, because of its low elasticity, even a concave portion having a complicated shape can be peeled off without causing damage such as deformation to the projected electrode to be transferred. Further, this is because even a warped substrate can be easily deformed in accordance with the warp so that the protruding electrode can be transferred.

  The recess 160 corresponding to the wiring pattern formed on the transfer mold 150 is, for example, a mold formed in the shape of a wiring pattern having a width of 5 μm to 300 μm, a thickness of 5 μm to 300 μm, and an aspect ratio of about 0.2 to 2.0. Can be formed on a transfer resin by imprinting or casting. For example, it can be formed by pouring a transfer type resin such as a thermosetting silicone resin into a mold and curing it at a temperature of 150 ° C. for 0.5 hours. In order to further improve the releasability, at least the recess 160 of the transfer mold 150 may be coated with, for example, a silicone-based release agent or a fluorine-based release agent.

  Next, as shown in FIG. 2B, paste-like, for example, silver is mainly used so that a space 190 is formed in the recess 160 of the transfer mold 150 without reaching at least the recess surface 180. The conductor 140 made of the conductive resin or solder is filled. In this case, the amount of the conductor 140 filled in the recess 160 can be determined by adjusting the mesh diameter of a screen printing mask, for example. Alternatively, the space 190 can be formed by filling the conductor surface 140 of the concave portion 160 and then drying the conductor 140 at a temperature not higher than the natural drying or curing temperature or lower than the melting point. Further, the space 190 may be formed by pressing the conductor 140 into the concave portion 160 using a roller made of a material having a low adhesion to the conductor 140 (for example, a fluororesin).

  Next, as shown in FIG. 2C, a space 190 formed in the recess 160 is filled with an insulating resin 130 made of, for example, an epoxy resin using the same method as the conductor 140.

  Next, as shown in FIG. 2D, the concave portion 160 of the transfer mold 150 filled with the insulating resin 130 and the conductor 140 and the substrate 100 are aligned.

  Next, as shown in FIG. 2 (e), the substrate 100 and the recess 160 of the transfer mold 150 are aligned and brought into close contact with each other and heated at a temperature equal to or higher than the curing temperature of the insulating resin 130 and the conductor 140. As a result, the wiring pattern 120 is cured. For example, when the insulating resin 130 and the conductor 140 include an epoxy resin, the curing temperature is 150 ° C. and the curing time is about 60 minutes. In this case, the insulating resin 130 needs to be cured at a temperature lower than the curing temperature or melting point of the conductor 140. However, when the insulating resin 130 and the conductor 140 are not mixed or melted with each other, the curing temperature of the insulating resin 130 may be higher than the curing temperature of the conductor 140. In addition, it is preferable that the insulating resin 130 and the conductor 140 can be further combined with each other by selecting and combining materials in such a degree that the insulating resin 130 and the conductor 140 are melted or diffused only in the vicinity of the interface. Is.

  By this step, the wiring pattern 120 is cured on the substrate 100 in the same shape as the shape of the recess 160.

  Then, as shown in FIG. 2 (f), the wiring pattern 120 having a uniform height is transferred onto the substrate 100 by peeling off the transfer mold.

(Embodiment 2)
FIG. 3A is a plan view of a wiring board according to Embodiment 2 of the present invention, and FIG. 3B is a cross-sectional view taken along line AA in FIG.

  The wiring board according to the second embodiment of the present invention is different from the wiring board according to the first embodiment in that a protruding electrode is provided at a predetermined position of the conductor.

  That is, in FIG. 3A, the wiring substrate has a wiring pattern 220 formed on a substrate 100 such as a resin substrate, and has a protruding electrode 210 at a predetermined position of the wiring pattern 220. Further, as shown in FIG. 3B, the wiring pattern 220 includes an insulating resin 230 on the substrate 100 side and a conductor 240 laminated thereon, and a protruding electrode on the conductor 240. 210 is formed. The protruding electrode 210 is made of the same material as the conductor 240. Here, the predetermined position where the protruding electrode 210 is provided means, for example, a position where the bump electrode 210 is connected to a terminal electrode of an electronic component such as a semiconductor chip, or a position where the chip component is mounted.

  With this configuration, since the protruding electrode 210 can be formed integrally with the wiring pattern 220, a wiring board with excellent productivity can be realized.

  Further, as shown in the following manufacturing method, the wiring pattern 220 having the protruding electrodes 210 can be formed with a fine pitch by the transfer mold 150 having the concave portions 160. Further, it can be easily formed with a high aspect ratio and can be formed with a uniform height.

  Note that as the substrate 100, the insulating resin 230, and the conductor 240, those described in Embodiment Mode 1 can be similarly used.

  Here, for example, when the terminal electrode of the electronic component and the protruding electrode 210 are melted and connected, the curing temperature of the conductor 240 made of a conductive resin is preferably higher than the curing temperature of the insulating resin 230. This is because, when the curing temperature of the insulating resin 230 is higher than the curing temperature of the conductor 240, the conductor 240 is already cured when the wiring pattern 220 is transferred to the substrate 100. In addition, when the curing temperature at the time of transfer is lower than the curing temperature of the conductor 240, the insulating resin 230 under the bump electrode 210 is deformed when connected to the terminal electrode of the electronic component via the bump electrode 210, and adjacent to it. This is because there is a possibility of short-circuiting between the protruding electrodes 210 to be performed.

  When the conductor 240 is formed of solder, it is preferable that the melting point of the solder that is the conductor 240 is higher than the curing temperature of the insulating resin 230. This is because if the melting point of the conductor 240 is lower than the curing temperature of the insulating resin 230 when transferring to the substrate 100, the conductor 240 is already melted when the insulating resin 230 is cured. This is because the wiring pattern 220 having a desired resistance cannot be formed because 230 and the conductor 240 are mixed. However, this does not apply when not mixed.

  As described above, the wiring pattern 220 can be formed in which the adhesion between the substrate 100 and the conductor 240 is greatly improved by the adhesive strength of the insulating resin 230. Therefore, the wiring pattern 220 does not peel from the substrate 100 even when deformation such as thermal stress, external impact, or warp is applied to the substrate 100, so that a highly flexible and highly reliable wiring substrate can be realized. Further, by forming the bump electrodes 210 at a predetermined position of the conductor 240, it is possible to easily connect to other electronic components and realize a wiring board with excellent productivity.

  Below, the manufacturing method of the wiring board which concerns on Embodiment 2 of this invention is demonstrated using FIG.

  FIG. 4 is a process cross-sectional view illustrating a method for manufacturing a wiring board according to Embodiment 2 of the present invention.

  First, as shown in FIG. 4A, a transfer mold having a recess 250 corresponding to a position where a wiring pattern is formed and a bottomed hole 260 corresponding to a protruding electrode at a predetermined position on at least the inner bottom surface of the recess 250. 150 is prepared. The transfer mold 150 is made of, for example, a transfer mold resin made of a thermosetting silicone resin or the like and having a low elastic modulus and high releasability. Here, the recess 250 corresponding to the wiring pattern formed in the transfer mold 150 has a width of 30 μm to 300 μm and a thickness of about 20 μm to 300 μm, for example, and the bottomed hole 260 corresponding to the protruding electrode has a diameter of 30 μm to 300 μm, for example. The height is about 40 μm to 300 μm.

  Then, a recess 250 and a bottomed hole 260 are formed by imprinting or intaglio printing a transfer mold resin with a mold having the above-described wiring pattern and protruding electrodes formed in a convex shape. For example, it can be formed by pouring a transfer type resin such as a thermosetting silicone resin into a mold and curing it at a temperature of 150 ° C. for 0.5 hours. In order to further improve the releasability, at least the recess 250 and the bottomed hole 260 of the transfer mold 150 may be coated with, for example, a fluorine-based mold release agent.

  Next, as shown in FIG. 4B, the bottomed hole 260 is completely filled in the recess 250 of the transfer mold 150 and at least the space 190 is formed without reaching the recess surface 180. In addition, a conductive material 240 made of, for example, a conductive resin mainly composed of silver or solder is filled. In this case, the amount of the conductor 240 filled in the recess 250 can be adjusted by, for example, the mesh diameter of the screen printing mask or the speed of the squeegee 170. Alternatively, the space 190 may be formed by filling the concave surface 180 of the transfer mold 150 and then shrinking the conductor 240 by drying at a temperature not higher than the natural drying or curing temperature. Further, the space 190 may be formed by pressing the conductor 240 into the recess 250 using a roller made of a material having a low adhesive force to the conductor 240 (for example, a fluororesin).

  Next, as shown in FIG. 4C, the insulating resin 230 made of, for example, an epoxy resin is filled into the space formed in the recess 250 using the same method as that for the conductor 240.

  Next, as shown in FIG. 4D, the concave portion of the transfer mold 150 filled with the insulating resin 230 and the conductor 240 and the substrate 100 are aligned.

  Next, as shown in FIG. 4E, in a state where the substrate 100 and the concave portion of the transfer mold 150 are aligned and in close contact with each other, the curing temperature of the insulating resin 230 and the curing temperature or melting point of the conductor 240 are equal to or higher. The wiring pattern 220 is cured by heating at a temperature. For example, in the case of an insulating resin 230 containing an epoxy resin having a curing temperature of 130 ° C. and a conductor 240 having a curing temperature of 140 ° C., the curing temperature is 150 ° C. and the curing time is about 60 minutes. Further, for example, in the case of the conductor 240 made of the insulating resin 230 containing an epoxy resin having a curing temperature of 150 ° C. and solder having a melting point of 220 ° C., the curing temperature is 230 ° C. and the curing time is about 10 minutes.

  In addition, the said hardening conditions assumed the case where the projection electrode 210 formed on the conductor 240 of the wiring pattern 220 and the terminal electrode of an electronic component are connected by, for example, ultrasonic bonding, pressure welding, pressure bonding or adhesion. Is.

  On the other hand, when the terminal electrode of the electronic component and the protruding electrode 210 are connected by fusion bonding with the protruding electrode 210, the insulating resin 230 and the conductor 240 are made of a material mainly composed of a thermosetting resin. In some cases, it is necessary to cure at a temperature equal to or higher than the curing temperature of the insulating resin 230 and equal to or lower than the curing temperature of the thermosetting resin constituting the conductor 240. Then, when the terminal electrode of the electronic component and the protruding electrode 210 are connected, the terminal electrode of the electronic component is temporarily softened by setting the temperature to be equal to or higher than the curing temperature of the thermosetting resin constituting the conductor 240. Can be connected. In this case, since the curing temperature of the insulating resin 230 is lower than the curing temperature of the conductor 240, the shape of the wiring pattern 220 is not deformed because the insulating resin 230 is already cured and does not soften.

  In addition, when the insulating resin 230 is made of a material mainly composed of a thermosetting resin and the conductor 240 is composed of solder having a melting point higher than the curing temperature of the insulating resin 230, the melting point of the conductor 240 is temporarily exceeded. After the conductor 240 is melted at the temperature, it may be cooled and cured. Then, when the terminal electrode of the electronic component and the protruding electrode 210 are connected, by setting the melting point of the conductor 240 or higher, the conductor 240 is once melted and can be connected to the terminal electrode of the electronic component. That is, since the curing temperature of the insulating resin 230 is lower than the melting point of the solder which is the conductor 240, the insulating resin 230 does not soften. Therefore, the shape of the wiring pattern 220 is not deformed. Here, it is preferable that the vicinity of the surface of the protruding electrode 210 of the conductor 240 facing the terminal electrode of the electronic component is equal to or higher than the melting point.

  By this step, the wiring pattern 220 having the protruding electrode 210 is cured in the same shape as the shape of the recess 250 provided with the bottomed hole 260 on the substrate 100.

  Then, as shown in FIG. 4F, a wiring pattern 220 having protruding electrodes 210 having a uniform height and substantially the same shape as the transfer mold is transferred onto the substrate 100 by peeling the transfer mold. is there.

(Embodiment 3)
FIG. 5A is a plan view of the electronic component mounting body according to Embodiment 3 of the present invention, and FIG. 5B is a cross-sectional view taken along the line AA in FIG. ) Is a cross-sectional view taken along the line BB in FIG.

  In FIG. 5, an electronic component mounting body is configured by connecting the protruding electrodes 210 formed on the wiring pattern 220 of the substrate 100 of the second embodiment and the terminal electrodes 310 of an electronic component 300 such as a semiconductor chip. is there.

  With this configuration, when connecting to the terminal electrode 310 of the electronic component 300, it is not necessary to form a protruding electrode on the terminal electrode 310, and the wiring pattern 220 and the protruding electrode 210 are collectively produced by the transfer mold, so that production is possible. An electronic component mounting body can be manufactured with good performance.

  Further, as described in the second embodiment, since the connection can be made even when the protruding electrode 210 is fused to the terminal electrode 310 of the electronic component 300, a reliable connection can be achieved. Further, in the case where the protruding electrode 210 is, for example, solder, when the connection distance is kept constant due to high wettability with the terminal electrode 310 of the electronic component 300 when the solder is re-melted, FIG. As shown in (c), it is possible to connect with a so-called drum-shaped protruding electrode 210 in which the central portion of the protruding electrode 210 is reduced. As a result, stress concentration at the interface between the terminal electrode 310 and the protruding electrode 210 is eliminated as compared with a conventional solder bump that tends to have a drum shape, and a highly reliable connection that hardly causes peeling of the electrode or the like can be realized. In this case, it is more effective if the area of the connection surface between the protruding electrode 210 and the terminal electrode 310 is smaller than the area of the terminal electrode 310.

(Embodiment 4)
6A is a plan view of a wiring board according to Embodiment 4 of the present invention, FIG. 6B is a cross-sectional view taken along the line AA in FIG. 6A, and FIG. FIG. 7 is a cross-sectional view taken along line BB in FIG.

  The wiring board of the fourth embodiment is different from the wiring board of the first embodiment in that wiring patterns are three-dimensionally stacked.

  As shown in FIG. 6A, the wiring board includes a first wiring pattern 420 on the substrate 100, and a second wiring that intersects the first wiring pattern 420 three-dimensionally as shown in FIG. 6B. The wiring pattern 520 is provided. The first wiring pattern 420 is formed by a laminated structure of the first insulating resin 430 and the first conductor 440. Similarly, the second wiring pattern 520 is formed by a laminated structure of the second insulating resin 530 and the second conductor 540.

  With this configuration, there is no need for three-dimensional wiring via via holes or the like as in a conventional multilayer wiring board, and wiring can be performed on the same surface except for the intersection of wiring patterns. Then, electronic components that need to be connected with a three-dimensional wiring pattern can be mounted in a planar manner.

  In addition, since the second insulating resin 530 of the second wiring pattern 520 can be used as an interlayer insulating layer with the first conductor 440 of the first wiring pattern 420, a three-dimensional wiring with strong adhesion is realized. it can. As a result, even with a flexible substrate, it is possible to realize a highly reliable wiring substrate in which each wiring pattern is hardly peeled off from the substrate 100 or disconnected.

  Below, the manufacturing method of the wiring board based on Embodiment 4 of this invention is demonstrated using FIG.

  FIG. 7 is a process cross-sectional view illustrating a method for manufacturing a wiring board according to Embodiment 4 of the present invention.

  First, as shown in FIG. 7A, a wiring board having a first wiring pattern 420 is prepared on a substrate 100 manufactured by the same manufacturing method as in the first embodiment.

  Next, as shown in FIG. 7B, in the recess 160 of the transfer mold 150 in which the recess 160 is formed at a position corresponding to the second wiring pattern, at least the recess surface 180 is not reached and the space 190 is reached. Is filled with a paste-like second conductor 540 made of, for example, a conductive resin mainly composed of silver or solder using a squeegee 170 such as screen printing. Here, as the transfer mold 150, for example, a transfer resin having a low elastic modulus and high releasability made of a thermosetting silicone resin or the like is used. The space 190 of the recess 160 is formed by the same method as in the first embodiment.

  Next, as shown in FIG. 7C, a second insulating resin made of, for example, an epoxy resin is used in the space 190 formed in the concave portion 160 by using a method similar to that of the second conductor 540. Fill 530.

  Next, as shown in FIG. 7D, the wiring board on which the recess 160 of the transfer mold 150 and the first wiring pattern 420 filled with the second insulating resin 530 and the second conductor 540 are formed. And align. Note that the direction of the transfer mold 150 shown in the figure is shown by a cross section in the longitudinal direction of the recess 160 shown in FIG. 7C in order to clarify the relationship with the first wiring pattern 420.

  Next, as shown in FIG. 7E, the transfer mold 150 is deformed along the shape of the first wiring pattern 420. In this state, the second wiring pattern 520 is cured by heating at a temperature equal to or higher than the curing temperature of the second insulating resin 530 and the second conductor 540. For example, when the second insulating resin 530 and the second conductor 540 include a thermosetting resin mainly composed of an epoxy resin, the curing temperature is 150 ° C. and the curing time is about 60 minutes.

  By this step, the second wiring pattern 520 is cured on the substrate 100 in the same shape as the concave portion 160 while being three-dimensionally wired on the first wiring pattern 420.

  Then, as shown in FIG. 7F, the second wiring pattern 520 that is three-dimensionally wired in a part of the first wiring pattern 420 is transferred onto the substrate 100 by peeling the transfer mold. Is.

  In the wiring board according to the fourth embodiment of the present invention, the distance between the first wiring patterns 420 is set so that the transfer mold 150 for forming the second wiring pattern 520 is sufficiently along the cross section of the first wiring pattern 420. It must be able to be deformed. Even in this case, needless to say, the second wiring pattern 520 can form a fine pitch within a transferable range.

  Further, as a modification of the wiring board according to the fourth embodiment of the present invention, as described in the second embodiment, the first conductor of the first wiring pattern or the second conductor of the second wiring pattern is used. A protruding electrode can also be formed on the body.

  As a result, a wiring board on which electronic components such as a semiconductor chip can be easily mounted via the protruding electrodes of the wiring board having a three-dimensional wiring is realized. Furthermore, an electronic component mounting body on which electronic components are mounted can be realized using this wiring board, as in the third embodiment.

  In each embodiment of the present invention, the protruding electrode has a trapezoidal cross-sectional shape and a conical shape has been described as an example. However, the present invention is not limited to this. For example, the cross-sectional shape may be rectangular as shown in FIG. 8 (a), or the cross-sectional shape may be triangular as shown in FIG. 8 (b). It has the effect of. Further, similarly, the planar shape does not need to be particularly circular, and is not particularly limited as long as it is a shape that can be peeled from the concave portion of the transfer mold.

  Since the wiring board of the present invention has excellent adhesion and can form a fine wiring pattern on a flexible substrate, it is mounted on a large-scale integrated circuit or an imaging device having a high density and a fine pitch. Useful in the field of electronic equipment.

(A) Plan view of the wiring board according to the first embodiment of the present invention (b) AA line sectional view of FIG. Process sectional drawing explaining the manufacturing method of the wiring board which concerns on Embodiment 1 of this invention (A) Plan view of a wiring board according to the second embodiment of the present invention (b) AA line sectional view of FIG. 3 (a) Process sectional drawing explaining the manufacturing method of the wiring board which concerns on Embodiment 2 of this invention (A) Plan view of electronic component mounting body according to Embodiment 3 of the present invention (b) AA line sectional view of FIG. 5 (a) (c) BB line sectional view of FIG. 5 (a) (A) Plan view of a wiring board according to Embodiment 4 of the present invention (b) AA line sectional view of FIG. 6 (a) (c) BB line sectional view of FIG. 6 (a) Process sectional drawing explaining the manufacturing method of the wiring board which concerns on Embodiment 4 of this invention Sectional drawing which shows the modification of the protruding electrode in embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Substrate 120,220 Wiring pattern 130,230 Insulating resin 140,240 Conductor 150 Transfer mold 160,250 Concave 170 Squeegee 180 Concave surface 190 Space 210 Protruding electrode 260 Bottomed hole 300 Electronic component 310 Terminal electrode 420 First wiring Pattern 430 First insulating resin 440 First conductor 520 Second wiring pattern 530 Second insulating resin 540 Second conductor

Claims (1)

Filling the first recess and the second recess with a conductive paste so as not to exceed the height of the first recess and the thermosetting silicon transfer mold provided with the second recess at the bottom of the first recess;
Filling the conductor with an insulating resin having a curing temperature lower than the curing temperature or melting point of the conductor paste to the height of the first recess;
Placing the insulating resin side of the transfer mold on a substrate and heating to mix or melt the conductor paste and the insulating resin ;
And a step of peeling the transfer mold from the substrate and forming a conductive pattern corresponding to the first recess on the flexible substrate through the insulating resin.

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