JP2004356324A - Method and apparatus of manufacturing wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method which enables the formation of a multilayer wiring board having a very fine IVH structure for all the layers. <P>SOLUTION: This manufacturing method includes a process wherein protection films (102) are pasted on both faces of an electric insulation substrate (101), and via holes (103) are formed in the electric insulation substrate (101). Then the via holes (103) are filled up with a conductor (104), and the protection films (102) are removed and the electric insulation substrate (101) is positioned and stacked on a body which is to be formed with an interconnection. In the positioning and stacking process, with the electric insulation substrate (101) fixed to a supporting body (105), the protection film on the non-fixed face is removed. After the electric insulation substrate is positioned and stacked on the body which is to be formed with an interconnection, the remaining protection film on the opposite side is removed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a wiring board in which vias for electrically connecting respective wiring layers of a multilayer wiring board and lands formed in the wiring layer are positioned with high precision.
[0002]
[Prior art]
In recent years, with the miniaturization and high performance of electronic devices, multilayer wiring boards on which semiconductor chips such as LSIs can be mounted at a high density have been strongly supplied inexpensively in the field of consumer devices as well as in industrial applications. Requested. In such a multilayer wiring board, it is important that a plurality of wiring patterns formed at a fine wiring pitch can be electrically connected with high connection reliability.
[0003]
As a first conventional example, an arbitrary electrode of a multilayer wiring board is replaced with a metal-plated conductor on the inner wall of a through-hole, which has been the mainstream of the conventional interlayer connection of a multilayer wiring board in response to such market demand. An inner via hole connection method that allows interlayer connection at the wiring pattern position, that is, an all-layer IVH structure resin multilayer substrate has been proposed (Patent Document 1 below). This is because it is possible to fill the via hole of the multilayer wiring board with a conductor and connect only the necessary layers, and to provide the inner via hole directly below the component land, so that the board size can be reduced and high-density mounting can be achieved. Can be realized. In addition, since the conductive connection is used for the electrical connection in the inner via hole, the stress applied to the via hole can be reduced, and stable electrical connection can be realized against a dimensional change due to thermal shock or the like.
[0004]
A multilayer wiring board manufactured by the steps shown in FIGS. 12A to 12I has been conventionally proposed as this all-layer IVH structure resin multilayer board (for example, see Patent Document 2). First, 701 shown in FIG. 12A is an electrically insulating base material. As the electrically insulating substrate, a porous substrate having compressibility, a three-layer structure in which an adhesive layer is formed on both sides of a core film, a composite substrate of fiber and resin, and the like are used. As shown in FIG. 12A, protective films 702 are attached to both sides of an electrically insulating substrate 701 by laminating. Subsequently, as shown in FIG. 12B, a via hole 703 that penetrates all of the electrically insulating substrate 701 and the protective film 702 is formed by a laser or the like. Next, as shown in FIG. 12C, the via holes 703 are filled with a conductive paste 704. This protective film serves to prevent the conductive paste from remaining on the electrically insulating substrate. Thereafter, the protective films 702 on both sides are peeled off, and a foil-like wiring material 705 is laminated and arranged from both sides in this state, to obtain a state shown in FIG. 12D. Here, when the protective film on the surface of the electrically insulating substrate is peeled off, a dimensional change in the surface direction of the electrically insulating substrate occurs. This dimensional change occurs because the stress between the protective film and the electrically insulating substrate generated when the protective film 702 is formed on the electrically insulating substrate 701 is released. Next, in a step shown in FIG. 12E, the wiring material 705 is adhered to the electrically insulating base material 701 by heating and pressing. At this time, when the electrically insulating substrate 701 has a compressible characteristic, it contracts in the thickness direction by heating and pressing. In addition, the conductive paste 704 is compressed in the thickness direction by the heating and pressing process. Due to this compression, the metal fillers in the conductive paste come into high-density contact, and electrical connection between the wiring material 705 and the conductive paste 704 is realized. Next, as shown in FIG. 12F, the wiring material 705 is patterned to complete the double-sided wiring board 706. Next, as shown in FIG. 12G, on both sides of the double-sided wiring board 706, an electrically insulating base material 707 and a wiring material 708 filled with a conductive paste formed in the same process as shown in FIGS. Laminated. The via holes formed in the electrically insulating base material recognize the position of the wiring pattern of the double-sided wiring board 706 already formed, and perform laser processing based on the measurement result of the dimensional change in the surface direction of the double-sided wiring board 706. It is formed with the data corrected. The electrically insulating substrate 707 changes its dimensions when the protective film is peeled off, as in the example described above. The wiring material 708 is heated and pressurized in the step shown in FIG. At this time, the double-sided wiring board 706 and the electrically insulating base material 707 are simultaneously bonded. In the heating and pressurizing step, similarly to the step shown in FIG. 12E, the electrically insulating base material 707 contracts in the thickness direction, and the conductive paste 709 is compressed in the thickness direction. Due to this compression, the conductive paste 709 comes into contact with the wiring material 708 and the wiring 710 on the double-sided wiring board at a high density, and electrical connection is realized. Next, the multilayer wiring board shown in FIG. 12I is completed by patterning the wiring material 708 on the surface layer. Here, the example of the four-layer board is shown as the multilayer wiring board, but the number of layers of the multilayer wiring board is not limited to four, and the number of layers can be further increased in the same process.
[0005]
As a second conventional example, there has been proposed a structure for reducing the size of an inner via hole in order to realize higher-density interlayer connection and realizing high reliability. The manufacturing method and structural features of the wiring board shown here will be described with reference to FIGS. Note that the description of the portions already described with reference to FIG. 12 will be simplified. 13A to 13I are cross-sectional views illustrating a conventional method of manufacturing a wiring board for each main process. As shown in FIG. 13A, protective films 802 are formed on both sides of an electrically insulating substrate 801. Next, as shown in FIG. 13B, a via hole 803 penetrating the electrically insulating substrate is formed. Examples of the electrically insulating substrate include a porous substrate having compressibility, a three-layer structure in which an adhesive layer is formed on both sides of a core film, and a composite substrate of fiber and resin, as in the examples described above. Materials are used. In addition, via holes are generally formed by laser processing such as a carbon dioxide laser, an excimer laser, and a YAG laser as a method having excellent productivity. When the via hole is filled with the conductive paste, the state shown in FIG. 13C is obtained. Next, the wiring transfer base material 805 shown in FIG. 13D includes a support base material 806 and wiring 807 formed in a desired pattern on the support base material. In general, the wiring transfer substrate is formed by selectively etching only a copper foil into a desired pattern from a composite foil in which a copper foil is laminated on an aluminum foil. The formation of copper foil on aluminum foil is usually performed by electrolytic plating, and the stress between aluminum and copper is very small. In other words, the structure is such that the dimensional change in the plane direction when the wiring pattern is formed by etching the copper foil is reduced. When the wiring transfer base material 805, the electrically insulating base material 801 from which the protective film on the surface is peeled off, and the wiring material 808 are stacked and arranged, the state shown in FIG. 13D is obtained. Here, similarly to the first conventional example described above, when the protective film on the surface of the electrically insulating substrate is peeled off, a dimensional change in the surface direction of the electrically insulating substrate occurs. This dimensional change is because the stress between the protective film and the electrically insulating substrate, which is generated when the protective film 802 is formed on the electrically insulating substrate 802, is released. In FIGS. 13A to 13D, the process for forming the electrically insulating base material is described for simplicity, but actually, the wiring transfer base material 805 may be formed first. In this case, the via processing can be performed by recognizing the position of the already formed wiring pattern and correcting the laser processing data in accordance with the position of the wiring 807. It is formed in a state where the dimensional change in the surface direction of the electrically insulating base material is corrected to laser processing data. As shown in FIG. 8E, the wiring transfer base material 805, the electrically insulating base material 801 and the wiring material 808 are bonded by heating and pressing. At this time, the wiring on the wiring transfer base material is embedded in the electrically insulating base material 801. The conductive paste 804 filled in the via hole 803 is effectively compressed by the embedding of the wiring 807, and the metal filler in the conductive paste comes into high-density contact, so that electrical connection between the wiring 807 and the wiring material 808 is secured. Is done. Next, when the wiring material 808 on the surface is patterned by etching, a wiring substrate 809 having two wiring layers as shown in FIG. 13F is formed. Subsequently, when two layers of wiring boards 809 are positioned and laminated from both sides of the electrically insulating base material 810 filled with the conductive paste, the state shown in FIG. 13G is obtained. The electrically insulating substrate 810 is manufactured by the same manufacturing method as that of the already described electrically insulating substrate 801. Further, in the figure, the wiring transfer base materials to be laminated in a simplified manner are shown by the same wiring pattern, but actually, different wiring patterns are generally used. Next, when the electrically insulating substrates are bonded by heating and pressing, the state shown in FIG. 13H is obtained. Subsequently, when the supporting substrate 806 on the surface is removed, a multilayer wiring board is completed as shown in FIG. 13I. The removal of the support substrate shown here can be performed in different ways depending on the support substrate material. When a metal material is used as the support base, removal by dissolution with a chemical solution is a method with excellent productivity, and when a resin sheet is used as the support base, mechanical removal is common. It is a target.
[0006]
Here, an example of a four-layer board is shown as the multilayer wiring board. However, the number of layers of the multilayer wiring board is not limited to four, and the number of layers can be further increased in the same process.
[0007]
As a third conventional example, an all-layer IVH structure resin multilayer wiring board manufactured by the steps shown in FIGS. 14A to 14F has been proposed (for example, Patent Document 3). This manufacturing method will be described in detail with reference to the drawings. As shown in FIG. 14A, a wiring material 1002 is adhered to one side of an electrically insulating base material 1001. This wiring material may be formed by pressing a wiring material on only one side of the electrically insulating base material in a prepreg state by pressing, or a so-called copper foil is bonded to both sides of the electrically insulating base material as a wiring material. The copper foil on one side of the copper clad laminate may be removed by etching. Next, as shown in FIG. 14B, a via hole 1003 is formed in the electrically insulating substrate 1001 so that the wiring material 1002 is exposed at the bottom of the hole. This via hole is generally formed by laser processing in the same manner as described in the first and second conventional examples. Depending on the state of the laser processing, the resin of the electrically insulating substrate may remain on the bottom of the via hole, and it is more preferable to perform desmearing by plasma or a chemical after the laser processing. Next, as shown in FIG. 14C, a metal 1004 is deposited as a conductor in the via hole 1003 by electrolytic plating. When performing this electrolytic plating, an electrode is taken with the wiring material 1002. Although not shown, when performing electrolytic plating, a protective film is formed on the wiring material surface side so that the wiring material is not exposed to the electrolytic solution. Further, it is preferable to form an electrode with a copper plate or the like around the electrically insulating base material so that the current density in the via hole portion is stabilized during electrolytic plating. In the deposition of the metal by the electrolytic plating, a low-melting-point metal is formed at least on the outermost surface, and is formed so as to protrude from the surface of the electrically insulating substrate. As the low melting point metal, a plating deposited metal such as tin or solder is used. The low melting point metal is provided to secure electrical connection between layers in the via hole when forming a multilayer wiring board. Next, as shown in FIG. 14D, the wiring material 1002 is etched to form a desired wiring 1005. By the etching of the wiring 1005, the area where the electrically insulating base material 1001 and the wiring material 1002 are in contact changes, so that the dimension of the electrically insulating base material changes in the plane direction. This change is caused by the fact that the balance of the stress remaining between the two materials when the wiring material is attached to the electrically insulating base material changes by etching the wiring material. Therefore, this variation varies depending on the wiring pattern. In addition, the stress before wiring formed between the wiring material and the electrically insulating substrate varies depending on the substrate, and as a result, the dimensional variation of the electrically insulating substrate is largely induced. ing. Due to this dimensional change, it is difficult to position the via hole 1003 and the land formed as the wiring when the wiring 1005 is formed. Next, when the intermediate of the wiring board shown in FIG. 14D is positioned and laminated on both sides of the double-sided wiring board 1006, the state shown in FIG. 10E is obtained. Subsequently, the electrically insulating base material 1001 is adhered to the double-sided wiring board 1006 by heating and pressing. At this time, the low melting point metal formed on the surface of the metal 1004 filled in the via hole is melted, and electrical connection can be secured between the wirings on the double-sided wiring board. A wiring board is manufactured. This heating and pressing condition is performed at a temperature equal to or higher than the melting point of the low melting point metal on the surface of the metal 1004. The adhesion of the electrically insulating base material is performed by applying an adhesive to the surface of the electrically insulating base material when the electric insulating base material contains a thermosetting resin and the adhesiveness cannot be secured by heating and pressing. Adhesion can be ensured. This adhesive has a sufficiently low melt viscosity so that the adhesive remains between the low-melting-point metal and the wiring and does not hinder the electrical connection. The double-sided wiring board 906 shown here may be the double-sided wiring board shown in Conventional Example 1, or a wiring material may be further deposited on one side of the intermediate body of the wiring board shown in FIG. A double-sided wiring substrate that can be obtained by securing the electrical connection in the above and then patterning the wiring material by etching may be used. Further, the positioning and lamination shown in FIG. 14E is not limited to the illustrated example, and a multilayer wiring board may be formed by laminating only the intermediates of the wiring board shown in FIG. 14D.
[0008]
As a fourth conventional example, there has been proposed an all-layer IVH structure resin multilayer wiring board manufactured by steps shown in FIGS. 15A to 15F (for example, Patent Document 4). This manufacturing method will be described in detail with reference to the drawings. As shown in FIG. 15A, a wiring material 902 is adhered to one side of an electrically insulating base material 901. In this wiring material formation, a wiring material may be attached to only one side of the electric insulating base material in a prepreg state by pressing, or a copper foil serving as a wiring material may be attached to both sides of the electric insulating base material, so-called The copper foil on one side of the copper clad laminate may be removed by etching. Next, the wiring material 902 on one side is etched to form a desired wiring 903 (FIG. 15B). The dimensional change of the electrically insulating substrate 901 during the formation of the wiring is the same as in the above-described conventional example 3. Next, as shown in FIG. 15C, a via hole 904 is formed in the electrically insulating base material 901 so that the wiring 903 is exposed at the bottom of the hole. This via hole is generally formed by laser processing in the same manner as described in the first and second conventional examples. Depending on the state of the laser processing, the resin of the electrically insulating substrate may remain on the bottom of the via hole, and it is more preferable to perform desmearing by plasma or a chemical after the laser processing. In this laser processing, since the wiring 903 has already been formed, the position of this wiring pattern is recognized, the deviation from the design dimension of the wiring pattern is measured in advance, and the via processing data is corrected, so that the via hole can be formed. Via holes can be formed with high precision on lands to be arranged. Next, when the via hole 904 is filled with the conductive paste 905, the state shown in FIG. 15D is obtained. When an organic solvent is contained as a binder of the conductive paste, the organic solvent is generally added for the purpose of lowering the viscosity of the conductive paste and increasing the filling property of the via hole. In particular, as in the example shown in FIG. 15, it is difficult to fill the bottomed via hole with conductive paste at a high density to the bottom of the hole, and printing such as defoaming under reduced pressure and printing in vacuum is performed. By introducing the method, more stable filling of the conductive paste can be realized. Next, drying is performed to remove the organic solvent contained in the conductive paste. This drying step is preferably performed near the boiling point of the organic solvent from the viewpoint of shortening the drying time. However, the dimensional change of the electrically insulating substrate 901 occurs in this drying step. This dimensional change is caused by the dimensional change due to dehumidification of the electrically insulating base material, the dimensional change due to the resin skeleton of the electrically insulating base material, the dimensional change due to internal stress relaxation of the electrically insulating base material, the wiring material and the electrical insulating property. It appears as a composite result of various factors such as stress relaxation between base materials. Although not shown, when a protective film is used when filling the conductive paste, a dimensional change due to the peeling of the protective film is further given, as in the example described in the first conventional example. Next, when the intermediate of the wiring board shown in FIG. 15D is positioned and laminated on both sides of the double-sided wiring board 906, the state shown in FIG. 15E is obtained. Subsequently, the electrically insulating base material 901 is adhered to the double-sided wiring board 906 by heating and pressing, and electrical connection between the conductive paste 905 and the wiring on the double-sided wiring board can be secured. The multilayer wiring board is manufactured. The double-sided wiring board 906 shown here may be the double-sided wiring board shown in Conventional Example 1, or a sheet-like wiring material may be laminated and adhered to one surface of the intermediate body of the wiring board shown in FIG. After securing the electrical connection between the paste 905 and the wiring material, a double-sided wiring substrate that can be obtained by patterning the wiring material by etching may be used. Further, in the positioning and lamination shown in FIG. 15E, a multilayer wiring board may be formed by laminating only intermediates of the wiring board shown in FIG. 15D.
[0009]
[Patent Document 1]
JP-A-6-268345
[0010]
[Patent Document 2]
JP-A-7-283534, page 7, FIG.
[0011]
[Patent Document 3]
JP-A-2002-111216, page 5, FIG.
[0012]
[Patent Document 4]
JP-A-2000-38464, page 7, FIG.
[0013]
[Problems to be solved by the invention]
However, in the manufacturing methods shown in the above-mentioned conventional examples 1 and 2, the wiring pattern was formed due to a dimensional change of the electric insulating substrate when the protective film formed on the surface of the electric insulating substrate was peeled off. In order to match the land with the via hole provided in the electrically insulating base material, it is necessary to increase the land diameter to such an extent that dimensional change variation can be tolerated. In addition, in the manufacturing method shown in the above-mentioned conventional example 3, when the wiring is etched, a dimensional change of the electrically insulating base material occurs. In order to allow this dimensional variation, it is necessary to increase the land diameter so that the via holes can be aligned with the lands at the time of positioning and stacking when forming a multilayer substrate. In addition, in the manufacturing method shown in the conventional example 4 described above, in addition to the dimensional change of the electrically insulating base material when the wiring is etched as described in the conventional example 3, the electrical insulating base material is formed by a drying process after filling the conductive paste. A dimensional change of the material occurs. Due to this variation in dimensional change, it is necessary to make the land diameter large enough to allow a dimensional change in order to match the land formed as a wiring pattern with the via hole during positioning and lamination when forming a multilayer substrate. That is, in the above-described manufacturing method, when a multilayer wiring board having an all-layer IVH structure is formed, it is necessary to increase the land diameter in order to allow the above dimensional change variation, which reduces the land diameter and increases the density. This has been a problem in performing wiring formation. In addition, this dimensional change becomes remarkable when the diameter of the via hole is reduced and the thickness of the electrically insulating base material is reduced in order to form a higher-density wiring board, which is a problem when forming a high-definition multilayer wiring board. I have.
[0014]
An object of the present invention is to solve the above-described problems and to provide a manufacturing method capable of forming a high-definition multilayer wiring board having an all-layer IVH structure.
[0015]
[Means for solving the problem]
In order to achieve the above object, a method of manufacturing a wiring board according to the present invention includes applying a protective film to both surfaces of an electrically insulating substrate, forming a via hole in the electrically insulating substrate, and forming a conductor in the via hole. Filling, removing the protective film, and positioning and laminating the electrical insulating base material on the wiring formation body, wherein the positioning and laminating step supports the electrical insulating base material. In a state in which the protective film is fixed to the body, the protective film on the non-fixed surface is removed, and after positioning and laminating the electrically insulating base material on the formation body of the wiring, the remaining protective film is removed. And
[0016]
Another method of manufacturing a wiring board of the present invention is to form a wiring on one surface of an electrically insulating substrate, provide a via hole in the electrically insulating substrate and expose the wiring at the bottom of the hole, and form a conductor in the via hole. In the method of manufacturing a wiring board for filling and positioning and laminating the electrically insulating base material on the wiring forming body, when filling the conductor, the wiring side surface of the electrically insulating base material is fixed to a support. The positioning and lamination are performed in the fixed state.
[0017]
Yet another method of manufacturing a wiring board according to the present invention is to provide a via hole in an electrically insulating base material having a wiring material formed on one surface so that the wiring material is exposed at the bottom of the hole, and filling the via hole with a conductor. Patterning the wiring material, positioning the electrical insulating base material on a wiring forming body, and laminating the wiring board, when forming the wiring, the conductor exposed surface side of the electrical insulating base material It is fixed to a support and positioned and laminated in the fixed state.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
According to the method of manufacturing a wiring board according to the present invention, the protective film is removed in a state where the electric insulating base material is fixed to the support, so that the surface direction of the electric insulating base material by removing the protective film is removed. Dimensional change can be suppressed. In addition, after positioning and laminating the electrical insulating base material from which the protective film has been removed on one side of the wiring substrate, the remaining protective film is removed. The dimensional change in the surface direction of the conductive base material can be suppressed. As a result, the via holes formed in the electrically insulating base material and the lands formed as wiring can be positioned with high accuracy, so that the land diameter can be reduced.
[0019]
In the above-described method for manufacturing a wiring board, it is preferable that the electrically insulating substrate is fixed by suction under reduced pressure from the support side. By fixing the electrically insulating base material from the support side by suction under reduced pressure, the entire surface of the electrically insulating base material can be fixed, and the dimensional change of the electrically insulating base material can be suppressed even in a small area, and the pressure can be reduced. It is possible to easily fix and release the electrically insulating base material by switching the suction.
[0020]
In the above-described method for manufacturing a wiring board, it is further preferable that the reduced-pressure suction section provided on the support is provided so as to be located outside a via-hole forming region of the electrically insulating base material when fixed. When the electrically insulating base material is thinned, the bending when the electrically insulating base material is sucked by the reduced-pressure suction part becomes remarkable. Further, if the back surface of the via hole filled with the conductor is directly sucked by the reduced pressure suction unit, the conductor may fall off. These problems can be solved by disposing the reduced-pressure suction section outside the via hole formation region.
[0021]
In the above-described method for manufacturing a wiring board, it is more preferable that the fixing of the support and the electrically insulating substrate is performed via a porous sheet. When suction is performed under reduced pressure through the porous sheet, suction is spread over the entire surface of the porous sheet even though suction is performed from the reduced-pressure suction section formed on the support. The entire surface of the material can be fixed.
[0022]
In the above-described method for manufacturing a wiring board, it is preferable that the electrically insulating substrate is fixed to the support using static electricity. According to the fixing to the support by static electricity, the electrically insulating substrate can be fixed without adding tension to the surface of the electrically insulating substrate, and the dimensional change due to the fixing of the electrically insulating substrate. Can be further suppressed.
[0023]
In the above-described method for manufacturing a wiring board, the fixing of the electric insulating base material and the wiring forming body in the positioning and laminating step is performed by setting the electric insulating base material to be larger than the wiring forming body, Is preferably performed by discharging the air between the electrically insulative base material and the object on which the wiring is formed by suction under reduced pressure. In this way, by actively removing air between the electrically insulating base material and the wiring-formed body, even when the electrically insulating base material becomes thinner and the rigidity of the base material is reduced, wrinkles are reduced. It becomes possible to laminate the electrically insulating base material without causing the generation.
[0024]
In the above-described method for manufacturing a wiring board, it is preferable that the fixing of the electric insulating base material and the object on which the wiring is formed in the positioning and laminating step be performed by pressing the entire surface. The entire surface of the electrically insulating substrate is fixed to the wiring body by fixing the wiring body by pressing the entire surface, so that when the protective film is removed, the electrical insulating property is maintained even in a minute area. There is no displacement of the substrate.
[0025]
In the above-described method for manufacturing a wiring board, the conductor is a conductive paste containing a metal filler and a resin binder, and the resin binder is discharged when fixing the electric insulating base material to the support. preferable. The resin binder in the conductive paste, which prevents contact between the wiring material and the metal filler in the conductive paste, is positively discharged before the heating and pressurizing step, resulting in the contact between the high-density metal filler and the wiring material. And a highly reliable via hole connection can be realized.
[0026]
In the above-described method for manufacturing a wiring board, the conductor is a conductive paste containing a metal filler and a resin binder, and the resin binder is discharged when the electric insulating base material is fixed to the wiring body. Is preferred. The resin binder in the conductive paste, which prevents contact between the wiring material and the metal filler in the conductive paste, is positively discharged before the heating and pressurizing step. And a highly reliable via hole connection can be realized.
[0027]
In the above-described method for manufacturing a wiring board, it is preferable that a wall surface of the via hole is provided with an inclination, and a side having a small opening area is fixed to the support. When the thickness of the electrically insulating base material is reduced, the area holding the conductive paste on the via hole wall surface is substantially reduced. As a result, the conductive paste filled in the via holes during removal of the protective film is easily taken by the protective film. Further, on the side where the opening area of the via hole is large, the tapered shape of the wall surface of the protective film is in order of tper, so that the conductive paste is more easily removed. Therefore, first, the protective film on the side having the larger opening area is removed while the conductive paste is held by the thickness of both the electrically insulating base material and the protective film. Next, the conductive paste exposed on the side having the larger opening area after removing the protective film is brought into contact with the wiring, and the conductive paste is held in the opening portion. Further, the side where the conductive paste having the reverse taper of the tapered shape of the protective film wall surface is difficult to remove is finally removed. Thereby, the loss of the conductive paste due to the removal of the protective film can be suppressed, and stable electrical connection in the via hole can be secured.
[0028]
According to another manufacturing method of the present invention, in the conductor filling step, the wiring side surface of the electrically insulating base is fixed to the support, thereby suppressing a dimensional change of the electrically insulating base in the conductor filling step. can do.
[0029]
In the above-described method for manufacturing a wiring board, the conductor is a conductive paste containing a metal filler and an organic solvent, and the conductor filling step includes a step of drying the organic solvent. In the case of a method of manufacturing a wiring board including a step of drying an organic solvent, the dimensional change of the electrically insulating base material due to heat is large. Then, by fixing the wiring side surface of the electrically insulating base material to the support, the dimensional change of the electrically insulating base material can be more effectively suppressed.
[0030]
In the above-described method for manufacturing a wiring board, in the wiring forming step, it is more preferable that the wiring already formed on the support is transferred to the electrically insulating substrate, and the support is fixed to the electrically insulating substrate. . By using the wiring transfer base material in which the wiring is formed on the support in advance, it becomes possible to double as the support of the wiring transfer base material and the support in the conductor filling step, and to efficiently manufacture the wiring board. Can be.
[0031]
According to another manufacturing method of the present invention, in the wiring forming step, by fixing the wiring side surface of the electrically insulating base material to the support, the dimensional change of the electrically insulating base material in the conductor filling step is suppressed. be able to.
[0032]
In the above-described method for manufacturing a wiring board, it is more preferable that the conductor is a metal deposited by plating. By forming the conductor from a metal, a via hole having a lower resistance value can be realized.
[0033]
In the above-described method for manufacturing a wiring board, it is preferable that the electrically insulating substrate is a composite substrate having a thickness of 100 μm or less and an adhesive formed on both surfaces of a film. According to the production method of the present invention, it is possible to effectively suppress the dimensional change even in a composite base material in which an adhesive is formed on both surfaces of a film having a thickness of 100 μm or less in which a dimensional change is likely to occur. As a result, the positioning accuracy at the time of lamination can be improved.
[0034]
In the above-described method for manufacturing a wiring board, it is preferable that the electrically insulating base material is a composite base material having a thickness of 100 μm or less and impregnated with resin in a fibrous nonwoven fabric or a fibrous woven fabric. According to the production method of the present invention, it is possible to effectively suppress the dimensional change even in a fibrous nonwoven fabric or a composite substrate in which a resin is impregnated with a fiber woven fabric having a thickness of 100 μm or less, in which a dimensional change is likely to occur. As a result, the positioning accuracy at the time of lamination can be improved.
[0035]
In the above-described method for manufacturing a wiring board, it is preferable that the electrically insulating substrate is a substrate formed of a single thermoplastic resin or a composite material containing at least a thermoplastic resin having a thickness of 100 μm or less. By the manufacturing method of the present invention, it is possible to effectively suppress the dimensional change even in a substrate formed of a single thermoplastic resin having a thickness of 100 μm or less or a composite material containing at least a thermoplastic resin, in which the dimensional change easily occurs. It becomes possible. As a result, the positioning accuracy at the time of lamination can be improved.
[0036]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0037]
(Embodiment 1)
1A to 1K are cross-sectional views showing main steps in a method for manufacturing a wiring board according to the present embodiment. The description of the contents of the manufacturing method shown in FIG. First, 101 shown in FIG. 1A is an electrically insulating base material. As the electrically insulating substrate, a porous substrate having compressibility or a composite substrate of a fiber and a resin having a three-layer structure in which an adhesive layer is formed on both sides of a core film is used. As shown in FIG. 1A, protective films 102 are attached to both sides of an electrically insulating substrate 101 by laminating. During this lamination, the electrical insulating substrate and the protective film adhere at a high temperature, so that the stress caused by the difference in the coefficient of thermal expansion between the electrical insulating substrate and the protective film causes an interface between the electrical insulating substrate and the protective film. Has occurred. In addition, since the laminating process is performed while applying a tensile tension to the protective film material, a dimensional change of the protective film due to the pulling is one of the factors of the stress. In addition, a resin film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is used as the protective film, and a film having a thickness of about 5 μm to 20 μm is used.
[0038]
Subsequently, as shown in FIG. 1B, via holes 103 penetrating all of the electrically insulating base material 101 and the protective film 102 are formed by laser processing, punch processing, or the like. In the case where the wall surface of the via hole is inclined, it is more preferable to use laser processing. In the case of laser processing, the state of exposure to laser energy on the front and back surfaces of the electrically insulating substrate is different, so that it is easy to arbitrarily control the inclined shape on the via hole wall surface by changing the laser conditions.
[0039]
Next, as shown in FIG. 1C, the conductive paste 104 is filled in the via hole 103. Here, a material containing a metal filler and a resin binder is used as the conductive paste. Copper, silver, gold, tin, solder, and alloys thereof are used as the metal filler, and thermosetting resins such as epoxy and polyimide are generally used as the resin binder.
[0040]
Next, one surface side of the electrically insulating substrate is fixed with the support 105 (FIG. 1D). The fixation by the support suppresses a dimensional change in the surface direction of the electrically insulating base material when the protective film on the surface is peeled off. Here, the side of the via hole 103 having a small opening area is fixed by a support. Generally, the tapered shape of the protective film wall surface on the side where the opening area of the via hole is large is a forward taper, so that the conductive paste is more easily removed. Therefore, as will be described in detail later, the protective film on the side having a large opening area is removed while the conductive paste is held by the thickness of both the electrically insulating base material and the protective film. Next, the conductive paste exposed on the side having the larger opening area after removing the protective film is brought into contact with the wiring, and the conductive paste is held in the opening portion. Furthermore, the side on which the conductive paste having a tapered shape of a reverse taper on the protective film wall surface is difficult to remove is finally removed. Thereby, the loss of the conductive paste due to the removal of the protective film can be suppressed, and stable electrical connection in the via hole can be secured.
[0041]
The fixing of the electrically insulating substrate on the support 105 can be performed by forming the reduced-pressure suction section 108 on the support 105 as shown in FIGS. 3A and 3B. Here, an example in which a groove shape is formed as the reduced-pressure suction section is shown, and the reduced-pressure suction groove is provided so as to be located outside the via hole forming region of the electrically insulating base material. When the electrically insulating base material is thinned, the bending when the electrically insulating base material is sucked by the reduced-pressure suction part becomes remarkable. Further, if the back surface of the via hole filled with the conductor is directly sucked by the reduced pressure suction unit, the conductor may fall off. These problems can be solved by disposing the reduced-pressure suction section outside the via hole formation region.
[0042]
Further, as shown in FIGS. 4A and 4B, an arrangement of the reduced-pressure suction section 108 of the support 105 may be provided such that an isolated reduced-pressure suction section is located outside the via hole formation region. By providing the isolated reduced-pressure suction section in this manner, the tension that pulls the electrically insulating base material in the plane direction can be reduced, and as a result, the dimensional change in the plane direction of the electrically insulating base material can be suppressed. . Although the figure shows an example of a circular shape as an isolated reduced pressure suction unit, the shape is not limited to this, and the same effect can be obtained if it is isolated.
[0043]
Although the figure shows a case where the entire surface of the electrically insulating base material is fixed by the support 105, the fixing method is not limited to this, and a frame-shaped supporting base material is used. The same effect can be obtained by fixing the periphery of the base material.
[0044]
Further, as shown in FIG. 5, it is more preferable to provide a porous film 109 between the electrically insulating substrate and the support 105. When suction is performed under reduced pressure through the porous sheet, suction is spread over the entire surface of the porous sheet even though suction is performed from the reduced-pressure suction section formed on the support. The entire surface of the material can be fixed by suction under reduced pressure. As a result, a dimensional change in the surface direction of the electrically insulating substrate can be suppressed.
[0045]
In addition, as shown in FIG. 6, static electricity can be used for fixing the electrically insulating substrate to the support. According to the fixing to the support by static electricity, the electrically insulating substrate can be fixed without adding tension to the surface of the electrically insulating substrate, and the dimensional change due to the fixing of the electrically insulating substrate. Can be further suppressed.
[0046]
Thereafter, when the protective film 102 on the surface is peeled off, the state shown in FIG. 1E is obtained. Since one surface of the electrically insulating substrate is fixed, the position of the via hole does not change when this protective film is peeled off. In this state, as shown in the figure, the conductive paste protrudes from the surface of the electrically insulating substrate by the thickness of the protective film, and a large amount of the conductive paste can be secured.
[0047]
Next, the via holes are positioned and laminated on the double-sided wiring board 106 so as to match the lands of the double-sided wiring board 106. Here, in the drawing, the double-sided wiring board 106 is a double-sided wiring board formed by the manufacturing method of FIGS. As this double-sided wiring board, the double-sided wiring board shown in another conventional example may be used as long as the via hole is filled with a conductor.
[0048]
Next, in the step shown in FIG. 1F, the electrically insulating base material is temporarily fixed on the double-sided wiring board. This temporary fixing may be performed by locally heating the peripheral portion of the electrically insulating base material to melt and bond the resin of the electrically insulating base material. In addition, as this temporary fixing method, it is also possible to temporarily fix without applying a temperature by using an adhesive having tackiness at normal temperature. In addition, this temporary fixing is sufficient if it can suppress the dimensional change of the electrically insulating base material in the surface direction. It does not matter even if it is closely attached. By performing the temporary fixing by pressurizing the entire surface in this manner, the entire surface of the electrically insulating base material is fixed on the wiring of the double-sided wiring board, so when removing the protective film in a later step, even in a minute area. There is no displacement of the electrically insulating substrate.
[0049]
The positioning and lamination of the electrically insulating base material on the double-sided wiring board can also be performed by the manufacturing method shown in FIGS. As shown in FIG. 7A, the electrically insulating substrate 1101 is fixed by the support 1102, and the protective film on the surface is removed. After the electric insulating base material is positioned and laminated, the double-sided wiring board 1103 is fixed by the reduced-pressure suction unit 1105 provided inside the support 1104. Here, the electrically insulating substrate 1101 is set to be larger than the double-sided wiring board 1103, and the reduced-pressure suction portion 1106 of the support 1104 is exposed around the double-sided wiring board 1103.
[0050]
Next, as shown in FIG. 11B, after positioning and laminating, the vacuum insulating section 1106 is suctioned, and the suction of the vacuum suction section 1107 is released, whereby the electrically insulating base material 1101 is fixed to the support 1104. When releasing the suction of 1107, it is more preferable to set the suction section to normal pressure and completely remove the suction force. In this way, by actively removing air between the electrically insulating substrate and the double-sided wiring board, wrinkles are generated even when the electrically insulating substrate is thin and the rigidity as the substrate is reduced. It becomes possible to laminate the electrically insulating base material without the need.
[0051]
Next, when the support 105 is removed, the state shown in FIG. 1G is obtained. Here, when the protective film 102 on the surface is peeled off, the state shown in FIG. 1H is obtained. Here, on the surface from which the protective film has been peeled off, the conductive paste has a shape protruding from the surface of the electrically insulating base material as described above. Subsequently, as shown in FIG. 1I, a wiring material 107 is laminated on the surface of the electrically insulating base material. When the electrically insulating substrate is bonded by heating and pressing in this state, the state shown in FIG. 1J is obtained. This heating and pressurizing step is performed under the condition that the electrically insulating substrate 101 is completely bonded to the double-sided wiring board 106. As an example, when a thermosetting resin is contained in the electrically insulating substrate, the thermosetting resin is completely cured. Further, when a thermosetting resin is contained in the conductive paste, it is necessary to cure the resin in the conductive paste in this heating and pressing step. Specifically, when an epoxy resin is used as the thermosetting resin, 50 kgf / cm ² These can be cured under heating and pressing conditions of 200 ° C. and 1 hour.
[0052]
It is important that the metal filler contained in the conductive paste makes high-density contact during the heating and pressurizing step in terms of stabilizing the electrical connection in the via hole. When a compressible material is used as the electrically insulating base material, the electrically insulating base material shrinks in the thickness direction during the heating and pressurizing step, and higher density contact of the metal filler is realized.
When fixing the electrically insulating substrate 101 to the support 105, the electrically insulating substrate is sucked through the porous sheet 109 as in the example shown in FIG. More preferably, the contained resin binder is sucked into the porous sheet. By actively discharging the resin binder in the conductive paste that prevents contact between the wiring material and the metal filler in the conductive paste before the heating and pressurizing step, the contact between the high-density metal filler and the wiring material can be reduced as a result. And a highly reliable via hole connection can be realized.
[0053]
The same applies even if the resin binder in the conductive paste is further discharged from the protective film 102 side in a state where the electrically insulating base material 101 shown in FIG. 1G is temporarily fixed on the double-sided wiring board 106. The effect is obtained. As shown in FIG. 8B, a porous film or the like having a large resin absorbing effect is laminated on the exposed surface of the conductive paste of the electrically insulating base material 1201 shown in FIG. The resin binder of the paste can be discharged. More effectively, it is more preferable to perform vacuum suction from the surface side of the porous film 1202. Although FIG. 8 shows an example in which an electrically insulating base material is laminated on the wiring transfer base material 206, the same applies to a case where the wiring transfer base material 206 is a double-sided wiring board.
[0054]
Next, by patterning the surface wiring material 107, the multilayer wiring board shown in FIG. 1K is completed. Here, an example in which one layer of an electrically insulating base material is laminated on one side of the double-sided wiring substrate shown in FIG. 12F as a multilayer wiring substrate to form a three-layer wiring substrate is shown. The same effect can be obtained by performing the process from both sides of the substrate and forming a four-layer wiring substrate as in the example of FIG. Further, the number of layers of the multilayer wiring board is not limited to four, and the number of layers can be further increased by the same process.
[0055]
Also, in FIG. 1, an example in which an electrically insulating base material is laminated on a double-sided wiring board has been described, corresponding to the conventional example shown in FIG. 12, but the wiring transfer base material shown in FIG. The same effect can be obtained by the present invention also in the case of laminating an electrically insulating base material. FIGS. 2A to 2L show a manufacturing method corresponding to FIGS. 13A to 13F, and overlapping parts will be described in a simplified manner.
[0056]
As shown in FIG. 2A, protective films 202 are formed on both sides of an electrically insulating substrate 201. Next, a via hole 203 penetrating the electrically insulating base material and the protective film is formed by laser processing or the like. When the via hole 203 is filled with a conductive paste 204 as a conductor, a state shown in FIG. 2C is obtained. Subsequently, as shown in FIG. 2D, when the electrically insulating base material is fixed by the support 205 and the protective film 202 on the surface is peeled off, the state shown in FIG. 2E is obtained. Since the electrically insulating substrate is fixed to the support when the protective film is peeled off, the dimensional change in the surface direction of the electrically insulating substrate is suppressed. Next, as shown in FIG. 2F, when an electric insulating base material is positioned and laminated on the wiring transfer base material 206 on which a desired wiring pattern has been formed in advance, and temporarily fixed, the state shown in FIG. 2G is obtained. Next, as shown in FIG. 2H, when the support 205 is removed and the protective film 202 on the surface is removed, the state shown in FIG. 2I is obtained. Even when the protective film 202 is removed, the electrical insulating base material is temporarily fixed on the wiring transfer base material, so that the electrical insulating base material is prevented from changing in dimension in the plane direction. . In this state, as shown in FIG. 2J, the wiring material 207 is laminated from the surface, the electrically insulating base material is adhered to the wiring transfer base material by heating and pressing, and the conductive paste is thermally cured to establish the electrical connection in the via hole. When secured, the state shown in FIG. 2L is obtained.
[0057]
By using such a manufacturing method, the dimensional change in the surface direction of the electrically insulating base material can be suppressed as compared with the conventional example shown in FIG. In addition, it is possible to provide a multilayer wiring board having a smaller land diameter and a higher density.
[0058]
(Embodiment 2)
9A to 9H are cross-sectional views illustrating main steps in a method for manufacturing a wiring board according to the present embodiment. The description of the content of the manufacturing method shown in FIG. 9 which has already been described in the second conventional example will be simplified. As shown in FIG. 9A, a wiring material 1302 is adhered to one side of an electrically insulating base material 1301. This wiring material may be formed by pressing a wiring material on only one side of the electrically insulating base material in a prepreg state by pressing, or a so-called copper foil is bonded to both sides of the electrically insulating base material as a wiring material. The copper foil on one side of the copper clad laminate may be removed by etching. As the electrically insulating substrate, a porous substrate having compressibility or a composite substrate of a fiber and a resin having a three-layer structure in which an adhesive layer is formed on both sides of a core film is used. Next, as shown in FIG. 9B, via holes 1303 are formed in the electrically insulating base material 1301 so that the wiring material 1302 is exposed at the bottoms of the holes. The via hole is generally formed by laser processing. Depending on the state of the laser processing, the resin of the electrically insulating substrate may remain on the bottom of the via hole, and it is more preferable to perform desmearing by plasma or a chemical after the laser processing. Next, as shown in FIG. 9C, a metal 1304 is deposited as a conductor in the via hole 1303 by electrolytic plating. In the deposition of the metal by the electrolytic plating, a low-melting-point metal is formed at least on the outermost surface, and is formed so as to protrude from the surface of the electrically insulating substrate. As the low melting point metal, a plating deposited metal such as tin or solder is used. The low melting point metal is provided to secure connection between layers in the via hole when forming the multilayer wiring board. Next, as shown in FIG. 9D, the electrically insulating base material 1301 is fixed by the support 1305, and in this state, the wiring material 1302 on the surface is etched to form a desired wiring 1306. As the support 1305, a support in which an adhesive is formed on a metal surface is used. It is more preferable that the adhesive formed here is left on the surface of the electrically insulating base material 1301 later. As the adhesive, an epoxy resin, a phenol resin, a polyimide resin, or the like can be used as a thermosetting resin. This adhesive is in an uncured state when fixing the support and the electrically insulating substrate. As the adhesive for fixing the support 1305, an adhesive force that does not change the dimension of the electrically insulating base material in the plane direction is sufficient, and the adhesive does not necessarily need to be cured. Further, as the metal of the support, it is necessary to use a material that is not eroded by a chemical solution at the time of etching, and here, a stainless steel foil is used. The surface of the stainless steel foil is subjected to a release treatment so that the stainless steel foil can be easily peeled later. As a result, the adhesive remains on the electrically insulating substrate after the stainless steel foil is peeled off. Next, as shown in FIG. 9E, the surface on which the wiring is formed by etching is fixed to the support 1307. It is preferable that this fixing can be easily removed after the subsequent positioning and lamination. In this case, the aluminum plate was provided with a reduced-pressure suction unit, and fixed by reduced-pressure suction. Subsequently, when the support 1305 is peeled and removed, the state shown in FIG. 9F is obtained. At this time, as described above, the adhesive remains on the surface of the electrically insulating substrate. As described above, since the wiring material on the surface is etched with the electric insulating base material fixed, the balance of the stress remaining between the two materials when the wiring material is attached to the electric insulating base material, Even if it changes by etching the wiring material, the dimension of the electrically insulating substrate does not change. Next, the intermediate body of the wiring board shown in FIG. 9F is positioned on both sides of the double-sided wiring board 1308 and stacked as shown in FIG. 9G. In this state, when the electrically insulating base material 1301 is temporarily fixed on the double-sided wiring board and the support 1307 is removed, the state shown in FIG. 9H is obtained. Regarding the temporary fixation here, since an adhesive is formed on the surface of the electrically insulating base material 1301, it is efficient to use the adhesiveness of the adhesive. Of course, an adhesive may be formed. Subsequently, by applying heat and pressure, the electrically insulating base material 1301 is adhered to the double-sided wiring board 1308, and the low-melting-point metal formed on the surface of the metal 1304 filled in the via hole is melted. Electrical connection with the wiring is ensured. As a result, a multilayer wiring board is manufactured. The heating and pressing conditions are performed at a temperature equal to or higher than the melting point of the low melting point metal on the surface of the metal 1304. When the electrically insulating substrate contains a thermosetting resin and the adhesiveness cannot be secured by heating and pressing, an adhesive is applied to the surface of the electrically insulating substrate to improve the adhesiveness. Secure. This adhesive has a sufficiently low melt viscosity, and the adhesive remains between the low-melting-point metal and the wiring, and does not hinder the electrical connection. Note that the double-sided wiring board 1308 shown here is not particularly limited, as in the case already described in the conventional example. Further, the positioning and lamination shown in FIG. 9G is not limited to the example shown in the drawing, and only the intermediates of the wiring board shown in FIG. A substrate may be formed.
[0059]
(Embodiment 3)
10A to 10F are cross-sectional views showing main steps in a method for manufacturing a wiring board according to the present embodiment. The description of the content of the manufacturing method shown in FIG. 10 which has already been described in the fourth conventional example will be simplified.
[0060]
As shown in FIG. 10A, a wiring material 1402 is adhered to one side of an electrically insulating substrate 1401. The wiring material may be formed by pressing a wiring material on only one side of the electrically insulating base material in a prepreg state by pressing, or a copper foil bonded on both sides of the electrically insulating base material as a wiring material. The copper foil on one side of the clad laminate may be removed by etching. As the electrically insulating base material, a porous base material having compressibility, a three-layer structure in which an adhesive layer is formed on both sides of a core film, and a composite base material of fiber and resin are used. Here, it is more preferable that the resin component contained in the electrically insulating substrate includes a thermoplastic resin. As will be described in detail later, in the present embodiment, when an electrically insulating base material containing a thermosetting resin is used, there is a drying step for removing an organic solvent contained in the conductive paste. Curing of the thermosetting resin proceeds with the heat. That is, it is necessary to strictly control the curing of the electrically insulating substrate. On the other hand, when a thermoplastic resin is used, there is no need to control such curing of the resin, so that there is an advantage that the resin can be easily manufactured. Next, a desired wiring 1403 is formed by etching the wiring material 1402 on one side. The dimensional change of the electrically insulating substrate 1401 during the formation of the wiring is the same as in the second embodiment described above, and the electrical insulating substrate is fixed by the method described in the second embodiment. By doing so, this dimensional change can be suppressed. Next, as shown in FIG. 10C, a via hole 1404 is formed in the electrically insulating base material 1401 so that the wiring 1403 is exposed at the bottom of the hole. The via hole is generally formed by laser processing. Depending on the state of the laser processing, the resin of the electrically insulating substrate may remain on the bottom of the via hole, and it is more preferable to perform desmearing by plasma or a chemical after the laser processing. In this laser processing, since the wiring 1403 has already been formed, the position of this wiring pattern is recognized, the deviation from the design dimension of the wiring pattern is measured in advance, and the via processing data is corrected, so that the via hole can be formed. Via holes can be formed with high precision on lands to be arranged.
[0061]
Next, when the conductive paste 1406 is filled in the via hole 1404 in a state where the electrically insulating base material 1401 is fixed with the support 1405, the state shown in FIG. 10D is obtained. The fixing to the support 1405 here can be realized by the same method as that described in the first embodiment. Further, as the metal filler of the conductive paste, copper, silver, gold, tin, solder, and alloys thereof can be used as the metal filler as described in the first embodiment. An organic solvent may be included as a binder for the conductive paste. The organic solvent is generally added for the purpose of lowering the viscosity of the conductive paste and increasing the filling property of the via hole. In particular, as in the example shown in FIG. 10C, it is difficult to fill the bottomed via hole with the conductive paste at a high density to the bottom of the hole, not only to adjust the viscosity of the conductive paste but also to reduce the pressure. By introducing a printing method such as defoaming or printing in a vacuum, more stable filling of the conductive paste can be realized. Next, drying is performed to remove the organic solvent contained in the conductive paste. This drying step is preferably performed near the boiling point of the organic solvent from the viewpoint of shortening the drying time. Since the electrically insulating base material is fixed by the support 1405, a dimensional change in the surface direction of the electrically insulating base material in the drying step can be suppressed.
[0062]
Although not shown, when a protective film is used when filling the conductive paste, a dimensional change due to the peeling of the protective film is further given, as in the example described in the first conventional example. This dimensional change can also be suppressed by fixing the electrically insulating substrate with the support 1405.
[0063]
Next, the intermediate of the wiring board shown in FIG. 10D is positioned and laminated on both sides of the double-sided wiring board 1407 as shown in FIG. 10E, and the support 1405 is removed to obtain the state shown in FIG. 10F. Subsequently, the electric insulating base material 1401 is adhered to the double-sided wiring board 1407 by heating and pressing, and the electrical connection between the conductive paste 1406 and the wiring on the double-sided wiring board is ensured, whereby the multilayer wiring board is manufactured. . Note that the double-sided wiring board 1407 shown here is not particularly limited, as in the example described above. Further, the positioning and lamination shown in FIG. 10E is not limited to the example shown in FIG. 10D, and only the intermediate of the wiring board shown in FIG. A substrate may be formed.
[0064]
Further, the same effect can be realized by the method for manufacturing a wiring board shown in FIGS. 11A to 11F. 11A to 11F are cross-sectional views illustrating main steps of a method for manufacturing a wiring board. The description of the manufacturing method shown in FIG. 11 which has already been described in FIG. 10 will be simplified.
[0065]
As shown in FIG. 11A, a wiring 1501 is formed in a desired pattern on the surface of a support 1502, and a wiring transfer base material 1503 is formed. In this wiring transfer base material, a metal foil is used as a support 1502, and a wiring material is laminated on the surface. In the manufacturing method described in this embodiment, it is more preferable in terms of productivity that the support 1502 be mechanically peeled in a later step, and the wiring material is not metal-bonded to the support 1502. A material that is physically held by the support 1502 is preferable. That is, an adhesive force enough to mechanically peel and remove the support 1502 is appropriate. In order to achieve this close contact, a slightly tacky adhesive layer may be formed on the support 1502, or a thermoplastic resin that does not generate tackiness may be formed on the interface between the support 1502 and the wiring material 1501, The plastic resin may be microscopically adhered to the support 1502 and the wiring 1501 and held by the anchor effect.
[0066]
Next, as shown in FIG. 11B, an electrically insulating substrate 1504 is laminated and adhered on the wiring transfer substrate 1503. Examples of the electrically insulating substrate include a porous substrate having compressibility, a three-layer structure in which an adhesive layer is formed on both sides of a core film, and a composite substrate of fiber and resin. Preferably, the electrically insulating substrate contains a thermoplastic resin as in the example described above.
[0067]
Next, as shown in FIG. 11C, a via hole 1505 is formed in the electrically insulating base material 1504 so that the wiring 1501 is exposed at the bottom of the hole. As in the above-described example, the via hole is generally formed by laser processing.
[0068]
Next, when the conductive paste 1506 is filled into the via hole 1505 in a state where the electrically insulating base material 1504 is fixed by the support 1502 of the wiring transfer base material 1503, a state shown in FIG. 11D is obtained. Similar to the example described above, when filling the illustrated bottomed via hole with the conductive paste, it is more preferable that the conductive paste contains an organic solvent in terms of filling property, and the organic paste is filled after the conductive paste is filled. A solvent drying step is performed. Here, since the electrically insulating substrate is fixed by the support 1502, a dimensional change in the surface direction of the electrically insulating substrate in the drying step can be suppressed.
[0069]
Next, the intermediate of the wiring board shown in FIG. 11D is positioned and laminated on both sides of the double-sided wiring board 1507 as shown in FIG. 11E, and the support 1502 is removed to obtain the state of FIG. 11F. Subsequently, the electric insulating base material 1504 is adhered to the double-sided wiring board 1507 by heating and pressing, and at the same time, electrical connection is secured between the conductive paste 1506 and the wiring on the double-sided wiring board, whereby a multilayer wiring board is manufactured. . Note that the double-sided wiring board 1507 shown here is not particularly limited, as in the example described above.
[0070]
Further, the positioning and lamination shown in FIG. 11E is not limited to the example shown in FIG. 11D, and only the intermediate body of the wiring board shown in FIG. A substrate may be formed.
[0071]
As described above, by laminating the electrically insulating base material on the wiring transfer base material, the wiring substrate can be manufactured without attaching the support in a later step, and the wiring substrate can be manufactured by a method excellent in productivity. Can be formed.
[0072]
Note that the thickness of the electrically insulating base material described in the above-described first to fourth embodiments greatly affects the dimensional change.
[0073]
When a composite substrate having a thickness of 100 μm or less and an adhesive formed on both sides of the film is used as the electrically insulating substrate, the influence of the stress due to the lamination of the protective film causes the dimensional change of the electrically insulating substrate. And the effect of suppressing the dimensional change by employing the manufacturing method of the present invention is remarkable.
[0074]
When a composite substrate having a thickness of 100 μm or less and a resin impregnated in a fibrous nonwoven fabric or a textile woven fabric is used as the electrically insulating substrate, the density of the fibers in the electrically insulating substrate may cause the in-plane surface of the substrate to become loose. , The difference in physical properties becomes remarkable, and the in-plane dimensional change behavior largely varies. The method of the present embodiment is effective in suppressing the variation in dimensional change in the surface of the electrically insulating base material.
[0075]
Further, when a single thermoplastic resin or a composite material containing at least a thermoplastic resin having a thickness of 100 μm or less is used as the electrically insulating base material, the rigidity of the electrically insulating base material is low. It is easy for undulation and the like to occur, and it is difficult to position and laminate the electrically insulating base materials with high dimensional accuracy. The method for manufacturing a wiring board according to the present invention is also effective in solving this problem.
[0076]
【The invention's effect】
As described above, according to the method for manufacturing a wiring board of the present invention, when forming a multilayer wiring board having an all-layer IVH structure, it is possible to suppress a dimensional variation of the electrically insulating base material. Further, according to the present invention, the same effect can be obtained even when the diameter of the via hole is reduced and the thickness of the electrically insulating base material is reduced, and the positioning and laminating accuracy at the time of manufacturing a multilayer wiring board can be improved. That is, according to the present invention, it is possible to form a multilayer wiring board having a high-definition all-layer IVH structure.
[Brief description of the drawings]
FIGS. 1A to 1K are cross-sectional views showing main steps of a method for manufacturing a wiring board shown in Embodiment 1 of the present invention.
FIGS. 2A to 2L are cross-sectional views illustrating main steps of another method for manufacturing a wiring board according to the first embodiment of the present invention;
FIG. 3A is a cross-sectional view showing a state in which the electrically insulating base material is fixed to a support shown in Embodiment 1 of the present invention, and FIG. 3B is a view showing an arrangement of a reduced-pressure suction section of the support.
FIG. 4A is a cross-sectional view showing a state in which the electrically insulating base material is fixed to the support shown in Embodiment 1 of the present invention, and FIG. 4B is a view showing an arrangement of a reduced-pressure suction section of the support.
FIG. 5 is a cross-sectional view showing a state where the electrically insulating base material shown in Embodiment 1 of the present invention is fixed to a support.
FIG. 6 is a cross-sectional view showing a state in which the electrically insulating substrate shown in Embodiment 1 of the present invention is fixed to a support.
FIGS. 7A and 7B are cross-sectional views illustrating a step of positioning and laminating the electrically insulating base material according to the first embodiment of the present invention.
FIGS. 8A and 8B are cross-sectional views showing a method of discharging a resin binder of the conductive paste shown in Embodiment 1 of the present invention.
FIGS. 9A to 9H are cross-sectional views illustrating main steps of a method of manufacturing a wiring board according to Embodiment 2 of the present invention;
FIGS. 10A to 10F are cross-sectional views illustrating main steps of a method for manufacturing a wiring board described in Embodiment 3 of the present invention.
FIGS. 11A to 11F are cross-sectional views illustrating main steps of a method of manufacturing a wiring board according to Embodiment 3 of the present invention;
12A to 12I are cross-sectional views illustrating main steps of a conventional method for manufacturing a wiring board.
13A to 13 are cross-sectional views showing main steps of a conventional method for manufacturing a wiring board.
14A to 14F are cross-sectional views illustrating main steps of a conventional method for manufacturing a wiring board.
15A to 15F are cross-sectional views illustrating main steps of a conventional method for manufacturing a wiring board.
[Explanation of symbols]
101,201,701,707,801,810,901,1001,1101,1201,1301 Electrically insulating base material
102,202,702,802 Protective film
103, 203, 703, 803, 904, 1003, 1303 Via hole
104, 204, 704, 709, 804, 905 conductive paste
105, 205, 1102, 1104 Support
106, 206, 706, 906, 1006, 1103 Double-sided wiring board
107,705,708,808,902,1002,1302 Wiring material
108, 1105, 1106, 1107 Decompression suction unit
109,1202 Porous film
710,807,903,1005 Wiring
805 Wiring transfer substrate
806 Supporting substrate
809 Two-layer wiring board

Claims (18)

Paste protective films on both sides of the electrically insulating substrate,
Forming a via hole in the electrically insulating substrate,
Filling the via hole with a conductor,
Removing the protective film and positioning and laminating the electrically insulating base material on a wiring forming body, the method for manufacturing a wiring board,
In the positioning and laminating step, in a state where the electrically insulating base material is fixed to the support, the protective film on the non-fixed surface is removed, and after further positioning and laminating the electric insulating base material to the wiring body, And removing the remaining protective film. The method for manufacturing a wiring board according to claim 1, wherein the electrically insulating base material is fixed by suction under reduced pressure from the support body side. The method of manufacturing a wiring board according to claim 2, wherein the reduced-pressure suction section provided on the support is provided so as to be located outside a via-hole forming area of the electrically insulating base material when fixed. The method for manufacturing a wiring board according to claim 2, wherein the fixing of the support and the electrically insulating substrate is performed via a porous sheet. The method for manufacturing a wiring board according to claim 1, wherein the electrically insulating substrate is fixed to the support side by static electricity. The fixing of the electric insulating base material and the wiring forming body in the positioning and laminating, the electric insulating base material is made larger than the wiring forming body, and the reduced pressure suction is performed from the wiring forming body side so as to make close contact. 2. The method for manufacturing a wiring board according to item 1. The method for manufacturing a wiring board according to claim 1, wherein the fixing of the electric insulating base material and the wiring-formed body in the positioning lamination is performed by surface pressing. 2. The method according to claim 1, wherein the conductor is a conductive paste containing a metal filler and a resin binder, and the resin binder is discharged when fixing the electric insulating base material to the support. 3. 2. The wiring board according to claim 1, wherein the conductor is a conductive paste containing a metal filler and a resin binder, and discharges the resin binder when fixing the electrically insulating base material to the wiring-formed body. 3. Production method. The method for manufacturing a wiring board according to claim 1, wherein an inclined surface is provided on a wall surface of the via hole, and a side having a small opening area is fixed to a support body side. Form wiring on one side of the electrically insulating substrate,
Providing a via hole in the electrically insulating substrate and exposing the wiring at the bottom of the hole,
Filling the via hole with a conductor,
In a method for manufacturing a wiring board for positioning and laminating the electrically insulating base material on a wiring body,
When filling the conductor, a wiring side surface of an electrically insulating base material is fixed to a support, and positioning and lamination are performed in the fixed state. The method according to claim 11, wherein the conductor is a conductive paste containing a metal filler and an organic solvent, and the method includes a step of drying the organic solvent when filling the conductor. 13. The method of manufacturing a wiring board according to claim 11, wherein when forming the wiring, the wiring already formed on the support is transferred to the electrically insulating base material, and the support is fixed to the electrically insulating base material. Method. On an electric insulating base material having a wiring material formed on one surface, a via hole is provided so that the wiring material is exposed at the bottom of the hole, and the via hole is filled with a conductor.
Patterning the wiring material, a method for manufacturing a wiring board for positioning and laminating the electrically insulating base material on a wiring body,
When forming the wiring, a conductor exposed surface side of an electrically insulating base material is fixed to a support, and positioning and lamination are performed in the fixed state. The method according to claim 14, wherein the conductor is a metal deposited by plating. The method for manufacturing a wiring board according to any one of claims 1 to 15, wherein the electrically insulating substrate is a composite substrate having a thickness of 100 µm or less and an adhesive formed on both surfaces of a film. The method for manufacturing a wiring board according to any one of claims 1 to 15, wherein the electrically insulating base material is a composite base material obtained by impregnating a resin into a fiber nonwoven fabric or a fiber woven fabric having a thickness of 100 µm or less. The wiring board according to any one of claims 1 to 15, wherein the electrically insulating base material is a base material formed of a single thermoplastic resin or a composite material containing at least a thermoplastic resin having a thickness of 100 µm or less. Production method.

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