JP5200879B2 - Multilayer circuit board conductive filling material and filling method thereof - Google Patents

Description

The present invention is filled in the hole formed in the resin film used in the manufacture of multilayer circuit boards, multilayer circuit electrical conduction between the wiring layers metal filler for conductive, a component is sintered Ru is ensured The present invention relates to a substrate conductive filling material (hereinafter referred to as a conductive filling material) and a filling method thereof.

  Conductive filling material that fills holes formed in a resin film during the production of a multilayer circuit board and sinters a conductive metal filler as a constituent component to ensure electrical continuity between wiring layers and a filling method thereof Are disclosed in, for example, Japanese Patent Laid-Open No. 2003-86948 (Patent Document 1) and Japanese Patent Laid-Open No. 2003-182023 (Patent Document 2).

  6A and 6B are diagrams for explaining a method for manufacturing a multilayer circuit board using the same conductive paste as in Patent Document 1. FIGS. 6A to 6F are cross-sectional views for each manufacturing process of the multilayer circuit board 90. FIG. is there.

  In the manufacturing method of the multilayer circuit board 90 shown to Fig.6 (a)-(f), as shown to Fig.6 (a), on one side of the resin film 20 which consists of the thermoplastic resin 1 by a hot press first, Metal (copper) foil 2 is bonded together. Next, as shown in FIG. 6B, the copper foil 2 is processed into a predetermined conductor pattern P by etching. Next, as shown in FIG.6 (c), the bottomed hole H which makes the conductor pattern P a bottom by laser processing is opened in the predetermined position of the resin film 20. Next, as shown in FIG. Next, as shown in FIG. 6 (d), the bottomed hole H is filled with the conductive paste 4. Thereby, the resin film 20a made of the thermoplastic resin 1 having the conductor pattern P formed on one side and the bottomed hole H filled with the conductive paste 4 can be prepared.

  Next, as shown in FIG.6 (e), the resin films 20a-20f prepared similarly are reversed and laminated | stacked on the way like a figure. Finally, the laminate is heated and pressed by a hot press plate, and as shown in FIG. 6 (f), the resin films 20a to 20f made of the thermoplastic resin 1 are bonded to each other and the conductive paste 4 is sintered. Thus, the connection conductor 4a is formed, and the conductor patterns P are electrically connected to each other.

  Through the above steps, the multilayer circuit board 90 shown in FIG. 6F is manufactured.

  FIG. 7 is a diagram showing the state of filling the bottomed hole H with the conductive paste 4 in more detail, and is a diagram corresponding to each step of FIGS. 6 (c) and 6 (d). FIG. 7A is a schematic cross-sectional view showing how the bottomed hole H is formed on the surface of the sheet material 10, and FIG. 7B shows the filling of the bottomed hole H with the conductive paste 4. It is sectional drawing which shows the mode. FIG. 7C is a schematic cross-sectional view showing the state of change associated with the subsequent processing of the conductive paste 4 filled in the bottomed hole H.

  In addition, in the sheet | seat material 10 of FIG. 7, the same code | symbol was attached | subjected about the part similar to the resin film 20 shown in FIG. Further, at the time of forming the bottomed hole H, the copper foil 2 is processed into a predetermined conductor pattern P as shown in FIG. 6C. However, in FIG. It is shown.

  Although not shown in FIGS. 6C and 6D for the sake of brevity, generally, when the bottomed hole H is formed and the conductive paste 4 is filled, it is generally shown in FIGS. As shown, the protective film 3 is affixed on the surface opposite to the surface of the resin film made of the thermoplastic resin 1 on which the copper foil 2 is affixed. And in the hole formation process shown to Fig.7 (a), the laser beam by the laser processing apparatus L is irradiated to the sheet | seat material 10 from on the protective film 3, and the bottomed hole H which makes the copper foil 2 the bottom is formed. . The protective film 3 is for preventing the conductive paste 4 from adhering to the resin film surface other than the bottomed hole H, and is made of, for example, polyethylene terephthalate (PET). The bottomed hole H formed in the resin film is a fine hole having a diameter of about 100 μm and a depth of about 50 μm.

  Next, in the paste filling step shown in FIG. 7B, the conductive paste 4 supplied to the surface of the sheet material 10 in the vacuum container is mechanically passed over the protective film 3 using a squeegee (scalpel) S. Push into the bottom hole H and fill. The conductive paste 4 is a paste that is dispersed in a volatile solvent such as terpine to maintain a stable ratio of silver and tin using, for example, a fine powder of several μm of silver (Ag) and tin (Sn) as a metal filler. It is a shape.

Next, as shown in (1) of FIG. 7C, the conductive paste 4 immediately after filling the bottomed hole H is
Since the squeegee S fills the surface of the protective film 3 with a squeegee, the surface is flat.
Next, as shown in (2) of FIG. 7C, when the solvent evaporates, the surface of the conductive paste 4 at the center of the bottomed hole H is lowered, and the surface becomes a mortar shape. Next, as shown in (3) of FIG. 7C, when the protective film 3 is peeled off, the conductive paste 4 protrudes from the surface of the resin film made of the thermoplastic resin 1. Thus, a resin film in the same state as the resin film 20a shown in FIG. 6 (d) is obtained.
JP 2003-86948 A JP 2003-182023 A

  In the above-described conventional conductive paste 4 and its filling method, the surface of the conductive paste 4 at the center of the bottomed hole H is lowered by solvent evaporation after filling, as shown in FIG. The surface is mortar-shaped. In addition, the conductive paste 4 remaining on the surface of the sheet material 10 after filling is wiped away with the squeegee S. At this time, the conductive paste 4 filled in the bottomed hole H is scraped off and filled into the bottomed hole H. The surface of the conductive paste 4 may be recessed.

  Since the conductive paste 4 after solvent evaporation has poor shape retention, the protruding portion from the resin film surface of the conductive paste 4 shown in (3) of FIG. In particular, as described above, the conductive paste 4 whose surface is recessed and the protruding portion from the resin film surface has an acute angle is liable to collapse. Therefore, when the protective film 3 is peeled off or when the resin films 20a to 20f shown in FIG. Further, when the conductive paste 4 breaks down, there arises a problem of poor connection between the wiring layers and short circuit failure due to the broken conductive paste 4 powder. Therefore, the conventional multilayer circuit board 90 using the conductive paste 4 as a connecting conductor between the wiring layers. Has a low manufacturing yield.

  Therefore, the present invention provides a conductive filling material that can be easily handled during manufacturing as a connection conductor between wiring layers in a multilayer circuit board, and can improve connection reliability and manufacturing yield, and its filling. It aims to provide a method.

The invention of claim 1 is filled in the hole formed in the resin film used in the manufacture of multilayer circuit boards, electrical continuity between the wiring layers metal filler for conductive, a component is sintered a conductive filler material that will be secured, the resin film is made of thermoplastic resin, filler material for the conductive is said metal filler, unlike the binder component consisting of solvents, than the sintering temperature of the metal filler melt at low temperatures, room temperature is paraffinic hydrocarbons or fatty acids (hereinafter, referred to as a low-melting at room temperature solid wax material) in a solid state consist of a mixture of, the conductive filler material, be in a solid state at room temperature , conductive filler material is heated together with the resin film, filled in the hole is softened is characterized in Rukoto.

  As in the case of the conventional conductive paste, the conductive filling material is filled in the holes formed in the resin film during the production of the multilayer circuit board, and the conductive metal filler as a constituent component is sintered to form a wiring layer. It is a material that ensures electrical continuity.

On the other hand, unlike the conventional conductive paste, the conductive filling material has a low melting point that melts at a temperature lower than the sintering temperature of the metal filler and is in a solid state at room temperature, unlike a binder component composed of a metal filler and a solvent. It consists of a mixture of room temperature solid wax material, a solid state at room temperature. Therefore, when filling the conductive filling material into the holes formed in the resin film during the manufacture of the multilayer circuit board, the conductive filling material is heated with the resin film, and the conductive filling material is softened. Press to fill. Since the conductive filling material is softened at the time of indentation filling into the holes, it can be filled in the same manner as a conventional conductive paste.

  Next, when the filling of the holes is completed and the conductive filling material is cooled to room temperature together with the resin film, the conductive filling material returns to a solid state. Therefore, unlike the conventional conductive paste, the conductive filling material filled in the holes does not become a mortar-like surface due to the lowering of the solvent due to evaporation of the solvent. The trouble which is done can also be controlled. And unlike the conventional conductive paste after evaporation of the solvent, the shape retaining property is poor and it does not easily collapse. For this reason, at the time of manufacturing a multilayer circuit board, it is easy to handle when peeling the protective film affixed to the resin film or laminating the resin film, and the work time is shorter than when using a conventional conductive paste. It can be greatly shortened. In addition, since the shape retention after filling the holes is good, it is possible to suppress poor connection between wiring layers and short circuit failure, and improve the manufacturing yield of multilayer circuit boards compared to the case of using a conventional conductive paste. Can do.

  As described above, the conductive filling material is easier to handle at the time of manufacture as a connection conductor between wiring layers in a multilayer circuit board than the conventional conductive paste, and can improve connection reliability and manufacturing yield. The conductive filling material can be made.

In order to easily soften the conductive filling material by simple heating, it is preferable that the low melting point room temperature solid wax material has a melting point of 100 ° C. or lower as described in claim 2.

In order to prevent the low melting point room temperature solid wax material, which is a constituent element of the conductive filling material, from remaining to the last in producing a multilayer circuit board, it does not have an adverse effect. As described above, it is preferable that the low melting point room temperature solid wax material decomposes or volatilizes at a temperature lower than the sintering temperature of the metal filler.

In this case, as described in claim 4, for example, in the batch bonding process of the laminated resin films at the time of manufacturing the multilayer circuit board, the decomposition or volatilization of the low melting point room temperature solid wax material and the sintering of the metal filler are simultaneously performed. In order not to leave a residue of the low melting point room temperature solid wax material after bonding, the temperature at which the low melting point room temperature solid wax material decomposes or volatilizes is preferably 350 ° C. or lower.

As described in claim 5 For example, as the paraffinic hydrocarbon can select a paraffin or eicosane, as claimed in claim 6 if example embodiment, as the fatty acids, capric acid, undecyl acid, lauric Acids, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nodecanoic acid or arachidic acid can be selected.

The metal filler in the conductive filling material can be made of silver (Ag) and tin (Sn), for example, as described in claim 7 .

Further, the hole filling the conductive filler material, as described in claim 8, may be a bottomed hole to the base conductor pattern made of a metal foil formed on one surface of the resin film. Then, the filling material for the conductive found the conductor pattern is heated with a resin film is formed, is softened Ru filled in the bottomed hole.

  As described above, the conductive filling material is easier to handle at the time of manufacture as a connection conductor between wiring layers in a multilayer circuit board than the conventional conductive paste, and can improve connection reliability and manufacturing yield. This is a conductive filling material.

Therefore, as described in claim 9 , the conductive filling material includes the multilayer circuit board in which a plurality of the resin films are laminated, and the resin films are bonded to each other by batch heating and pressurization. It is suitable for a multilayer circuit board formed by sintering the metal filler. Then, before Kishirube conductive filler material is filled into the pores of the resin film, a plurality of sheets of the resin film to be laminated, Ru is heated under pressure at once.

The invention according to claim 1 0-19 is an invention relating to a method of filling the conductive filler material.

The invention according to claim 1 0 is filled in the hole formed in the resin film used in the manufacture of multilayer circuit boards, electrical conduction between the wiring layers metal filler for conductive, a component is sintered there a conductive filler material that will be secured, the resin film is made of thermoplastic resin, the conductive filler material is different from said metal filler, a binder component consisting of solvent, the sintering temperature of the metal filler melt at a lower temperature, room temperature is paraffinic hydrocarbons or fatty acids (hereinafter, referred to as a low-melting at room temperature solid wax material) in a solid state consist of a mixture of, the conductive filler material is in the solid state at room temperature A method for filling the conductive filler material, wherein the conductive filler material is heated together with the resin film, softened and filled into the holes, and the resin film is heated to room temperature or higher. Supplying the conductive filling material onto the heated resin film, filling the softened conductive filling material into the holes and filling, and cooling the resin film after filling to room temperature. And a cooling step for returning the conductive filling material to a solid state.

  Thereby, the hole can be easily filled with the conductive filler material, and the above-described effect of the conductive filler material can be exhibited.

  As described above, the conductive filling material has excellent shape retention, and is not scraped off excessively by wiping with a squeegee after filling the hole.

Therefore, in the filling method of the conductive filler material, in particular as described in claim 1 1, in the filling step, protected without using a film, on the surface of the resin film which has been heated to the conductive filler material You may make it supply directly to.

The filling method according to claims 12 to 19 corresponds to the filling of the conductive filling material according to claims 2 to 9 described above. About the effect acquired by filling, it is as above-mentioned, The description is abbreviate | omitted.

The present invention is filled in the hole formed in the resin film used in the manufacture of multilayer circuit boards, electrical conduction between the wiring layers metal filler for conductive, a component is sintered Ru is secured, conductive The present invention relates to a filling material and a filling method thereof.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing a conductive filling material 40 according to the present invention. FIG. 2 is a schematic cross-sectional view showing a state in which the conductive filling material 40 is filled into the holes H formed in the resin film 30. FIGS. 3A and 3B are schematic cross-sectional views showing changes in the conductive filling material 40 filled in the holes H due to subsequent processing. Moreover, FIG. 4 is a figure which shows the field using the resin film 30a to which the protective film 3 is not affixed, and is the typical cross section which showed the mode after filling about the filling material 40 for electroconductivity with which the hole H was filled. FIG. In addition, in the resin films 30 and 30a shown in FIGS. 2-4, the same code | symbol was attached | subjected about the part similar to the resin film 20 shown in FIG. 6, and the sheet | seat material 10 shown in FIG. Moreover, in FIG. 2, illustration of the protective film 3 in the resin film 30 is abbreviate | omitted.

The conductive filler 40 shown in FIG. 1 is composed of a mixture of a metal filler 41 and a low melting point room temperature solid wax material 42. The metal filler 41 is similar to the conductive metal filler contained in the conventional conductive paste 4 shown in FIGS. 6 and 7, and is sintered at the time of manufacturing the multilayer circuit board to provide electrical continuity between the wiring layers. It is a component for securing. The metal filler 41 is a fine metal powder having a particle size of several tens of μm or less, preferably several μm or less, and is composed of, for example, silver (Ag) and tin (Sn) that can be sintered at a relatively low temperature. Can do. On the other hand, the low melting point room temperature solid wax material 42 is melted at a temperature lower than the sintering temperature of the metal filler 41 and is in a solid state at room temperature, unlike a binder component made of a dispersant or a solvent contained in the conventional conductive paste 4. It is a wax material . Therefore, the conductive filling material 40 made of a mixture of the metal filler 41 and the low melting point room temperature solid wax material 42 is in a solid state at room temperature as shown in FIG.

FIG. 5 is a diagram showing a typical example of a wax material that can be used as the low melting point room temperature solid wax material 42 of the conductive filling material 40 together with the melting point.

As shown in FIG. 5, the low melting point room temperature solid wax material 42 may be, for example, paraffinic hydrocarbon, turpentine oil or fatty acid. More specifically, paraffin or eicosane can be selected as the paraffinic hydrocarbon. For example, the melting point of paraffin varies depending on the molecular weight, and those having a melting point of 42 to 70 ° C. can be used. As turpentine oil, for example, α-terpine can be selected. As the fatty acid, for example, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nodecanoic acid or arachidic acid can be selected.

  Since the conductive filling material 40 in FIG. 1 is in a solid state at room temperature, as shown in FIG. 2, the conductive filling material 40 is filled in the holes H formed in the resin film 30 while being heated.

  More specifically, a heater KH is embedded in the base stage BS on which the resin film 30 is placed. When the resin film 30 is held on the substrate stage BS by the vacuum chuck VC, the resin film 30 is heated to a predetermined temperature equal to or higher than room temperature by conduction heat from the heater KH. Next, when the conductive filling material 40 shown in FIG. 1 is supplied onto the heated resin film 30, the resin film 30 is softened by the conduction heat. As shown in FIG. 2, the softened conductive filling material 40 is pushed and filled into the holes H formed in the resin film 30 with the squeegee S.

  Thus, the conductive filling material 40 can be easily filled into the holes using the same method as the conventional one, and the effect of the conductive filling material 40 described later can be exhibited.

  When the filled resin film 30 is taken out from the base stage BS and cooled to room temperature, the conductive filling material 40 filled in the holes H of the resin film 30 gradually solidifies as shown in FIG. Return to state. Next, as shown in FIG. 3B, when the protective film 3 is peeled off, the conductive filling material 40 protrudes from the surface of the resin film 30.

  After preparing a plurality of resin films 30 as described above and laminating them in the same manner as in FIG. 6 (e), a batch bonding process by heating and pressurization shown in FIG. 6 (f) is performed. As a result, the resin films 30 adjacent to each other are bonded together, and the metal filler 41 of the conductive filling material 40 is sintered to form a connection conductor, and the conductor patterns are electrically connected to each other.

  Through the above steps, a multilayer circuit board similar to that shown in FIG. 6F can be manufactured.

  As described above, the conductive filling material 40 in FIG. 1 is formed in the holes H formed in the resin film 30 during the manufacture of the multilayer circuit board, as in the conventional conductive paste 4 shown in FIGS. It is a material which is filled in and sinters the conductive metal filler 41 which is a constituent component to ensure electrical conduction between the wiring layers.

On the other hand, unlike the conventional conductive paste 4 shown in FIGS. 6 and 7, the conductive filling material 40 of FIG. 1 melts at a temperature lower than the sintering temperature of the metal filler 41 and the metal filler 41 at room temperature. It consists of a mixture with a low melting point room temperature solid wax material 42 that is in a solid state, and is in a solid state at room temperature. Therefore, as shown in FIG. 2, when filling the conductive filling material 40 into the holes H formed in the resin film 30 during the manufacture of the multilayer circuit board, the conductive filling material is heated together with the resin film 30. After softening 40, the hole H is pushed and filled with a squeegee S or the like. Since the conductive filling material 40 is softened when the hole H is pushed and filled, it can be filled in the same manner as the conventional conductive paste 4.

  Next, as shown in FIG. 3, when the filling into the holes H is completed and the conductive filling material 40 is cooled to room temperature together with the resin film 30, the conductive filling material 40 returns to a solid state. Therefore, the conductive filling material 40 filled in the holes H is different from the conventional conductive paste 4 shown in FIGS. 6 and 7 in that the surface does not become a mortar due to the lowering of the surface due to evaporation of the solvent. It is also possible to suppress the problem of excessive scraping by removing the wipe with the squeegee. And unlike the conventional conductive paste 4 after evaporation of the solvent, the shape retaining property is poor and it does not easily collapse. For this reason, as shown in FIG. 3, when manufacturing the multilayer circuit board, it is easy to handle when peeling off the protective film 3 attached to the resin film 30 or laminating the resin film 30, and the conventional conductive Compared with the case where the paste 4 is used, the working time can be greatly shortened. In addition, since the shape retention after filling the hole H is good, it is possible to suppress poor connection between wiring layers and short circuit failure, and improve the production yield of multilayer circuit boards as compared with the case where the conventional conductive paste 4 is used. can do.

  Further, as described above, the conductive filling material 40 is excellent in shape retention, and is not scraped off excessively by wiping with a squeegee after filling the holes H. Therefore, in the filling method of the conductive filling material 40 described above, the conductive filling material 40 is heated on the surface of the resin film without the protective film 3 without passing through the protective film 3 in the filling step shown in FIG. You may make it supply directly to. In this case, as shown in FIG. 4, there is no problem that the surface of the conductive filling material 40 is excessively scraped off by wiping with the squeegee after filling and is not recessed, and the surface of the conductive filling material 40 after filling It becomes flat in line with the surface of the resin film 30a. The resin film 30a in which the conductive filling material 40 shown in FIG. 4 is filled in the holes H is also suitable for manufacturing a multilayer circuit board, like the resin film 30 shown in FIG.

  As described above, the conductive filling material 40 is easier to handle at the time of manufacture as a connection conductor between the wiring layers in the multilayer circuit board than the conventional conductive paste, and improves connection reliability and manufacturing yield. It is a conductive filling material that can be used.

The conductive filling material 40 is in a solid state at room temperature, and is characterized in that it is filled in the holes H formed in the resin film 30 by heating. Therefore, in order to easily soften the conductive filling material 40 by simple heating, the melting point of the low melting point room temperature solid wax material 42 as a constituent component is preferably 100 ° C. or less. Each resin material that can be employed as the low melting point room temperature solid wax material 42 illustrated in FIG. 5 is a resin material that has a melting point of 100 ° C. or lower and is in a solid state at room temperature.

The conductive filling material 40 is used to finally ensure electrical continuity between the wiring layers of the multilayer circuit board. Therefore, in order to prevent the low melting point room temperature solid wax material 42, which is a constituent element of the conductive filling material 40, from remaining to the last in producing the multilayer circuit board, there is no low melting point. The room temperature solid wax material 42 is preferably decomposed or volatilized at a temperature lower than the sintering temperature of the metal filler 41.

For example, as shown in FIG. 6F, in the batch bonding process of the laminated resin films at the time of manufacturing the multilayer circuit board, decomposition or volatilization of the low melting point room temperature solid wax material 42 and sintering of the metal filler 41 are performed. It is preferable that the temperature at which the low melting point room temperature solid wax material 42 is decomposed or volatilized is 350 ° C. or lower so that the residue of the low melting point room temperature solid wax material 42 does not remain after bonding.

  In the example shown in FIGS. 2 and 3, the hole H formed in the resin film 30 filled with the conductive filling material 40 is the bottom of the conductor pattern made of the copper foil 2 formed on one side of the resin film 30. It was a bottomed hole. However, the present invention is not limited to this, and the conductive filling material 40 returns to a solid state at room temperature and has sufficient shape retention, so that it is possible to fill a through hole without a bottom.

  As described above, the conductive filling material 40 is easier to handle at the time of manufacture than the conventional conductive paste 4 shown in FIGS. 6 and 7 as a connection conductor between wiring layers in a multilayer circuit board. It is a conductive filling material that can improve connection reliability and manufacturing yield.

  Therefore, the conductive filling material 40 is suitable for use in place of the conventional conductive paste 4 in the manufacturing process of the multilayer circuit board 90 described with reference to FIG. That is, in the conductive filling material 40, the resin film is made of a thermoplastic resin, the multilayer circuit board is laminated with a plurality of the resin films, and the resin films are bonded to each other by batch heating and pressurization. In addition, it is suitable for a multilayer circuit board in which the metal filler is sintered.

  Next, more specific examples will be described.

Example 1.
As the metal filler of the conductive filling material, spherical silver (Ag) powder with an average particle diameter of 5 μm and spherical tin (Sn) powder with an average particle diameter of 2.5 μm, the blending ratio of both is silver / tin = 7/3 It adjusted so that it might become. Next, 8 wt% of paraffin having a melting point of 43 ° C. was added as a low melting point room temperature solid wax material , and kneaded with the metal filler on a 60 ° C. hot plate. Next, a resin film made of a thermoplastic resin without a protective film is placed on a base stage set at 60 ° C. with a heater, and then the conductive filling material is squeezed into a bottomed hole with a copper foil as the bottom. And vacuum filled. Thereafter, the resin film filled with the conductive filling material was taken out from the base stage and placed on another stage without a heater, and it was confirmed with a contact-type surface thermometer that the resin film was at room temperature. Next, the conductive filling material remaining on the surface of the resin film was wiped off with a hard paper, and then the prepared plurality of resin films were superposed. In this superposition process, it was confirmed by observation with a metal microscope that the conductive filling material filled in the bottomed hole did not collapse due to vibration caused by handling or reverse lamination of the resin film. Next, the plurality of superposed resin films were heated and vacuum pressed under the conditions of 320 ° C., 40 min, 4 MPa. As a result of observing the cross section of the connection portion between the wiring layers in the multilayer circuit board obtained with a microscope, diffusion bonding with the copper foil was good, and the metal filler of the conductive filling material filled in the bottomed hole was It was confirmed that firing was good. Moreover, the electrical continuity was also good.

Example 2
Using the same metal filler as in Example 1, 8 wt% of eicosane having a melting point of 37 ° C. was added as a low melting point room temperature solid wax material , and kneaded with the metal filler on a 60 ° C. hot plate. Thereafter, a multilayer circuit board was produced through the same steps as in Example 1. As a result of observing the cross section of the connection part between the wiring layers in the obtained multilayer circuit board with a microscope, it was confirmed that the diffusion bonding with the copper foil was good and the metal filler was fired well. Moreover, the electrical continuity was also good.

Example 3
Using the same metal filler as in Example 1, 8 wt% of stearic acid having a melting point of 70 ° C. was added as a low melting point room temperature solid wax material , and kneaded with the metal filler on a hot plate at 100 ° C. Next, after placing a resin film made of a thermoplastic resin without a protective film on a base stage set at 100 ° C. with a heater, the squeegee is placed on the bottomed hole with the copper foil as the bottom. And vacuum filled. Thereafter, a multilayer circuit board was produced through the same steps as in Example 1. As a result of observing the cross section of the connection part between the wiring layers in the multilayer circuit board obtained with a microscope, it was found that, compared with Examples 1 and 2, which employed paraffin or eicosane as a low melting point room temperature solid wax material , Slightly inferior in nature. This is probably due to the difference in thermal decomposability between paraffin, eicosane and stearic acid. However, diffusion bonding with copper foil and electrical conduction were good.

  As described above, the conductive filling material and the filling method thereof are easier to handle at the time of manufacture than the conventional conductive paste as a connection conductor between wiring layers in a multilayer circuit board, and connection reliability and manufacturing A conductive filling material capable of increasing yield and a filling method thereof.

It is typical sectional drawing which showed the filling material 40 for electroconductivity which concerns on this invention. FIG. 3 is a schematic cross-sectional view showing a state where a conductive filling material 40 is filled into holes H formed in a resin film 30. (A), (b) is typical sectional drawing which showed the mode of the change accompanying a subsequent process about the filling material 40 for electroconductive with which the hole H was filled. It is a figure which shows the field using the resin film 30a in which the protective film 3 is not stuck, and is typical sectional drawing which showed the mode after filling about the filling material 40 for electroconductivity with which the hole H was filled. It is the figure which showed the typical example of the resin material which can be employ | adopted as the low melting-point room temperature solid wax material 42 of the filling material 40 for electroconductivity with melting | fusing point. FIG. 6 is a diagram for explaining a method for manufacturing a multilayer circuit board using a conductive paste similar to that of Patent Document 1, and (a) to (f) are cross-sectional views for each manufacturing process of the multilayer circuit board 90. It is the figure which showed the mode of filling of the conductive paste 4 to the bottomed hole H in detail. (A) is typical sectional drawing which showed the mode of formation of the bottomed hole H to the sheet | seat material 10 surface, (b) shows the mode of filling of the conductive paste 4 to the bottomed hole H. It is sectional drawing. Further, (c) is a schematic cross-sectional view showing a change in the subsequent processing with respect to the conductive paste 4 filled in the bottomed hole H.

1 Thermoplastic resin 2 Metal foil (copper foil)
3 Protective Film 30, 30a Resin Film H Hole 40 Conductive Filling Material 41 Metal Filler 42 Low Melting Point Room Temperature Solid Wax Material 90 Multilayer Circuit Board

Claims (19)

Filled into the formed hole in a resin film used for producing the multilayer circuit board, filling the multilayer circuit board conductive electrical conduction between the wiring layers metal filler for conductive, a component is sintered Ru is ensured Material,
The resin film is made of a thermoplastic resin,
The multilayer circuit board conductive filling material comprises:
Unlike the binder component comprising the metal filler and solvent , the paraffinic hydrocarbon or fatty acid (hereinafter referred to as a low melting point room temperature solid wax material) that melts at a temperature lower than the sintering temperature of the metal filler and is in a solid state at room temperature. )
The multilayer circuit board conductive filler material is a solid state at room temperature,
The multi-layer circuit is heated filler material for the substrate conductor, together with the resin film, softened by filler material for multilayer circuit board conductive, wherein Rukoto filled in the hole. 2. The multilayer circuit board conductive filling material according to claim 1, wherein the low melting point room temperature solid wax material has a melting point of 100 [deg.] C. or less. The low melting point room temperature solid wax material is
The multi-layer circuit board conductive filling material according to claim 1 or 2, which decomposes or volatilizes at a temperature lower than a sintering temperature of the metal filler. 4. The multilayer circuit board conductive filling material according to claim 3, wherein the decomposition or volatilization temperature is 350 ° C. or less. 5. The paraffinic hydrocarbon is
The multi-layer circuit board conductive filling material according to any one of claims 1 to 4, which is paraffin or eicosane . The fatty acid is
It is capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nodecanoic acid or arachidic acid, according to any one of claims 1 to 4. The multilayer circuit board conductive filling material as described. The said metal filler consists of silver (Ag) and tin (Sn) , The filling material for multilayer circuit board electroconductivity as described in any one of Claim 1 thru | or 6 characterized by the above-mentioned. The hole is a bottomed hole whose bottom is a conductor pattern made of a metal foil formed on one side of the resin film,
The filler material for a multilayer circuit board conductive is the conductor pattern is heated with a resin film is formed, any one of claims 1 to 7, characterized in that it is filled to be softened the bottomed hole Filling material for conducting a multilayer circuit board as described in 1. The multilayer circuit board is a multilayer circuit board in which a plurality of the resin films are laminated and the resin films are bonded to each other by batch heating and pressing, and the metal filler is sintered,
The multi-layer circuit board conductive filling material is a multi-layer circuit board conductive filling material which is filled in the holes of the resin film and heated and pressed together with a plurality of laminated resin films. The multilayer circuit board conductive filling material according to any one of claims 1 to 8, wherein: Multilayer circuit board conductive filling material that is filled in holes formed in a resin film used for manufacturing a multilayer circuit board, and a conductive metal filler as a constituent component is sintered to ensure electrical conduction between wiring layers. Because
The resin film is made of a thermoplastic resin,
The multilayer circuit board conductive filling material comprises:
Unlike the binder component comprising the metal filler and solvent, the paraffinic hydrocarbon or fatty acid (hereinafter referred to as a low melting point room temperature solid wax material) that melts at a temperature lower than the sintering temperature of the metal filler and is in a solid state at room temperature. )
The multilayer circuit board conductive filling material is in a solid state at room temperature;
Heating the multilayer circuit board conductive filling material together with the resin film, softening and filling the holes, filling the multilayer circuit board conductive filling material,
A heating step of heating the resin film to room temperature or higher;
Supplying the multilayer circuit board conductive filling material onto the heated resin film, and filling the softened multilayer circuit board conductive filler material into the holes by filling,
A cooling step of cooling the resin film that has been filled to room temperature to return the filling material for conducting a multilayer circuit board to a solid state, and a filling method for filling material for conducting a multilayer circuit board . In the filling step,
The method of filling a multi-layer circuit board conductive filler material according to claim 10 , wherein the multi-layer circuit board conductive filler material is directly supplied onto the heated surface of the resin film without using a protective film. . 12. The method for filling a multilayer circuit board conductive filling material according to claim 10, wherein the low melting point room temperature solid wax material has a melting point of 100 ° C. or less . The low melting point room temperature solid wax material is
The method for filling a multilayer circuit board conductive filling material according to any one of claims 10 to 12, wherein the metal filler is decomposed or volatilized at a temperature lower than a sintering temperature of the metal filler . 14. The method for filling a multilayer circuit board conductive filling material according to claim 13 , wherein the decomposition or volatilization temperature is 350 ° C. or lower . The paraffinic hydrocarbon is
Filling method of the multilayer circuit board conductive filler material according to any one of claims 1 0 to 14, which is a paraffin or eicosane. The fatty acid is
15. Capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nodecanoic acid or arachidic acid, according to any one of claims 10 to 14 A filling method of the filling material for a multilayer circuit board according to the description. Wherein the metal filler is silver (Ag) and the filling method of the multilayer circuit board conductive filler material according to any one of claims 1 0 to 16, characterized in that it consists of tin (Sn). The hole is a bottomed hole whose bottom is a conductor pattern made of a metal foil formed on one side of the resin film,
18. The multi-layer circuit board conductive filling material is heated together with the resin film on which the conductive pattern is formed, softened, and filled into the bottomed holes. 18. A filling method of the filling material for a multilayer circuit board according to the description. The multilayer circuit board is a multilayer circuit board in which a plurality of the resin films are laminated and the resin films are bonded to each other by batch heating and pressing, and the metal filler is sintered,
19. The multi-layer circuit board conductive filling material filled in the holes of the resin film is collectively heated and pressed together with the plurality of laminated resin films . The filling method of the filling material for multilayer circuit board conductivity as described in any one of Claims .

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