JP2004186453A - Multilayer wiring board and method for manufacturing the same, and component mounting board and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayer wiring board and the multilayer wiring board, and a method for manufacturing a component mounting board and the component mounting board by which a step can be simplified and the resistance of electric connection between conductor patterns can be made lower in the multilayer wiring of a wiring board using a transfer method. <P>SOLUTION: The method includes a step for forming a first conductor pattern 24 in a transferring supporting body 21, a step for forming a conductive bump 26a by etching a conductive bump formation layer 26 selectively, a step for sticking the first conductor pattern 24 to the conductive bump 26a together with the transferring supporting body 21, a step for forming a second conductor pattern 27a by patterning a conductor 27 stacked on the bump formation layer 26, and a step for separating the transferring supporting body 21 from the first conductor pattern 24. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a multilayer wiring board in which a plurality of conductor patterns are connected between layers and a method of manufacturing the same, an element mounting board in which elements are mounted on the multilayer wiring board, and a method of manufacturing the same. More specifically, the present invention relates to a multilayer wiring board having a transfer film transferred by a transfer method as a conductor pattern, a method of manufacturing the same, an element mounting board having elements mounted on the multilayer wiring board, and a method of manufacturing the same.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as electronic devices such as mobile phones, PDAs (Personal Digital Assistants), and notebook personal computers have become smaller and more sophisticated, high-density mounting of electronic components constituting these devices has become indispensable. 2. Description of the Related Art High-density mounting of electronic components has conventionally been promoted by miniaturization of electronic components, finer pitch of component terminals, miniaturization of conductor patterns on wiring boards on which electronic components are mounted, and the like.
[0003]
In recent years, the development of a multilayer wiring board that enables three-dimensional wiring by stacking a plurality of wiring boards has been promoted. Also, development of a device mounting board incorporating a device such as a semiconductor bare chip or the like and further improving the mounting efficiency has been promoted.
[0004]
2. Description of the Related Art As a method for forming a conductor pattern on a wiring board, a transfer method using a transfer sheet has been conventionally known. The process of manufacturing a wiring board by this transfer method mainly includes a pattern forming step of forming a conductor pattern on one surface of a transfer sheet, and bonding the formed conductor pattern together with the transfer sheet to an insulating layer, and then separating the transfer sheet. And a pattern transfer step.
[0005]
As a prior art of this type, for example, Patent Document 1 discloses a method of manufacturing a multilayer wiring board in which a conductor pattern (wiring pattern) on a wiring board is formed by a transfer method. Hereinafter, a conventional method for manufacturing a multilayer wiring board will be described with reference to FIG.
[0006]
[Patent Document 1]
JP-A-10-107445
[0007]
First, as shown in FIG. 13A, a wiring board having a first conductive pattern 2 formed on the surface of an insulating base material 1 is prepared or prepared.
[0008]
Next, as shown in FIG. 13B, an insulating slurry is applied to the surface of the insulating base material 1 to form the insulating layer 3.
[0009]
Next, as shown in FIG. 13C, a via hole 4 communicating with the first conductive pattern 2 is formed in the insulating layer 3 by laser processing or the like, and the inside of the formed via hole 4 is filled with a conductive paste 5.
[0010]
Next, as shown in FIG. 13D, the second conductor pattern 6 previously formed on the transfer sheet 7 is transferred to the insulating layer 3, and the first conductor pattern 6 is , The second conductor patterns 2 and 6 are connected.
[0011]
The transfer sheet 7 is mainly composed of a synthetic resin material such as polyethylene terephthalate (PET). The conductor pattern 6 is formed by patterning a conductor layer adhered or deposited on the transfer sheet 7 into a predetermined shape by a wet etching method. The transfer of the conductor pattern 6 from the transfer sheet 7 to the insulating layer 3 is performed using a difference in adhesion between the conductor pattern 6 and the insulating layer 3 and the transfer sheet 7.
[0012]
When three or more conductor layers are formed, the same steps as described above are repeated. That is, as shown in FIG. 13E, an insulating layer 8 is further formed on the insulating layer 3, a via hole is formed in the insulating layer 8, and the formed via hole is filled with the conductive paste 10, and then the third insulating layer 8 is formed. Is formed by a transfer method.
[0013]
[Problems to be solved by the invention]
In the above conventional example, since the electrical connection between the different wiring layers is made by the conductive paste, the steps of laminating the insulating layer, the step of drilling, the step of filling the conductive paste, and the like are required, which complicates the process and reduces the cost. However, there is a problem that the tact time is increased and the tact time at the time of manufacturing becomes long. In addition, a conductive paste in which conductive particles are dispersed in a paste-like insulating material has a higher resistance than a via composed of only a conductive material.
[0014]
The present invention has been made in view of the above-described problems, and an object of the present invention is to simplify the process and reduce the resistance of electrical connection between conductor patterns in a multilayer wiring of a wiring board using a transfer method. It is an object of the present invention to provide a method for manufacturing a multilayer wiring board, a method for manufacturing a multilayer wiring board, a method for manufacturing an element mounting board, and an element mounting board which can be achieved.
[0015]
[Means for Solving the Problems]
The method for manufacturing a multilayer wiring board according to the present invention includes a step of forming a first conductive pattern on a transfer support, a step of selectively etching a conductive bump forming layer to form a conductive bump, Attaching the first conductive pattern to the conductive bumps together with the transfer support, patterning the conductor laminated on the bump formation layer to form a second conductive pattern, and attaching the transfer support to the first conductive pattern. Separating from the conductor pattern.
[0016]
In the multilayer wiring board of the present invention, the first conductor pattern, which is a transfer film transferred from the transfer support,
Via the conductive bump formed by selectively etching the conductive bump formation layer,
It is characterized by being connected to a second conductor pattern formed by patterning a conductor laminated on the bump formation layer.
[0017]
The method for manufacturing an element mounting substrate according to the present invention includes a step of forming a first conductive pattern on a transfer support, a step of selectively etching a conductive bump formation layer to form a conductive bump, Attaching the first conductive pattern to the conductive bumps together with the transfer support, patterning the conductor laminated on the bump formation layer to form a second conductive pattern, and attaching the transfer support to the first conductive pattern. The method is characterized by including a step of separating from the conductor pattern and a step of mounting the element by electrically connecting to the first and second conductor patterns.
[0018]
In the element mounting board of the present invention, the first conductor pattern, which is a transfer film transferred from the transfer support,
Via the conductive bump formed by selectively etching the conductive bump formation layer,
Connected to a second conductor pattern formed by patterning a conductor laminated on the bump formation layer,
An element electrically connected to the first and second conductor patterns is mounted.
[0019]
The first conductor pattern and the second conductor pattern are formed in independent steps. The first conductor pattern is formed on the transfer support, and the second conductor pattern is formed integrally with the conductive bump. Then, after attaching the first conductor pattern to the conductive bumps together with the transfer support, the transfer support is separated from the first conductor pattern. Thereby, the first conductor pattern is connected to the second conductor pattern via the conductive bump.
[0020]
The transfer support functions as a support for maintaining the flatness of the first conductor pattern and improving the handleability. Therefore, it is configured to have mechanical properties such as strength and material properties such as heat-resistant temperature to meet this requirement.
[0021]
The transfer support is finally separated from the first conductor pattern and does not remain.
It is preferable to have a release layer for facilitating the separation.
Examples of the release layer include a configuration in which a plurality of metal layers are stacked. In the case of this configuration, there is an advantage that dimensional change or deterioration does not occur even after a heating step of, for example, about 300 ° C.
[0022]
Another configuration of the release layer includes a resin layer in which a release agent is applied to a predetermined portion of the surface to be released. Further, a heat-foaming layer may be used as another release layer. In this case, the transfer support can be peeled off by foaming the heat-foamable layer by heating to a predetermined temperature.
[0023]
Alternatively, without providing the release layer, the transfer support may be dissolved and separated from the first conductor pattern.
[0024]
If the transfer support is made conductive, a fine-pitch conductive pattern can be formed by using a pattern plating technique based on an additive method.
[0025]
When forming the conductive bump and the second conductor pattern, the conductive bump and the second conductor pattern having an easily integrated structure are processed by using the bump forming layer and the conductor laminated on each other as a starting material. Is obtained. For example, by etching both sides of the laminated body of the bump forming layer and the conductor, a conductive bump and a second conductor pattern having an integrated structure can be obtained. Either of the formation of the conductive bump and the formation of the second conductor pattern may be performed first or after. The second conductor pattern may be formed before or after the first conductor pattern and the conductive bump are bonded.
[0026]
In addition, if the bump forming layer is laminated in contact with the conductor surface having a different etching resistance from the bump forming layer, the conductor is not eroded when the bump forming layer is etched, and conversely, the bump forming layer is not eroded when the conductor is etched. Therefore, the formation of the conductive bump and the formation of the second conductor pattern can be performed with high accuracy.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0028]
(First Embodiment)
First, a method for forming a first conductor pattern will be described with reference to FIGS.
[0029]
(Step of FIG. 1A)
The transfer support 21 is manufactured by laminating the release layer 23 on the support substrate 22. FIG. 2 shows the details of the configuration of the transfer support 21.
[0030]
The support substrate 22 is a substrate made of, for example, Cu, occupies most of the entire thickness of the transfer support 21, and has a mechanical property or a material property required for handling the transfer support 21. Be composed. The thickness is, for example, about 140 μm.
[0031]
The release layer 23 includes two metal layers 23a and 23b. A Cr layer (for example, 0.01 μm in thickness) 23a is laminated on the support substrate 22, and a Ni / Co (alloy) layer (for example, 0.15 μm in thickness) 23b is laminated on this Cr layer 23a. Both are formed by an electroplating method using the support substrate 22 as a power supply.
[0032]
The Cr layer 23a and the Ni / Co layer 23b have a characteristic that they do not undergo diffusion bonding even at a temperature of, for example, about 320 ° C., and therefore can be easily peeled off even when subjected to a hot press in a later step. In this case, peeling is possible at the boundary between the Cr layer 23a and the Ni / Co layer 23b.
[0033]
(Step of FIG. 1B)
The first conductor pattern 24 is formed on the transfer support 21. Specifically, first, after a photoresist film is formed on the surface of the release layer 23 (the surface of the Ni / Co layer 23b), the photoresist film is exposed and developed to pattern the photoresist film into a desired shape. Form a plating resist.
[0034]
Subsequently, the transfer support 21 is immersed in a copper electrolytic bath and connected to the cathode electrode to deposit a copper electroplating film (first conductive pattern) 24. After the formation of the plating film 24, the plating resist is removed.
[0035]
In general, compared to a method of forming a conductor pattern by removing unnecessary portions of a conductor film by a wet etching method (subtractive method), a method of forming a conductor pattern by depositing a conductor film only in a necessary portion by an electroplating method ( According to the present embodiment, the first conductor pattern 24 having a fine pitch such as a line and space (L / S) of, for example, 10 μm / 10 μm can be formed by the additive method). It can be formed with high precision. Note that the thickness of the first conductor pattern 24 is, for example, about 3 μm.
[0036]
Further, since the first conductor pattern 24 is formed on the supporting substrate 22 made of Cu which is thicker and smaller in dimensional change than a resin film or the like, handleability in a later step is improved, and the first conductor pattern 24 is made thinner. It can be formed and the dimensional accuracy can be stabilized.
[0037]
Next, a method for forming a conductive bump will be described with reference to FIG. This step is performed independently of the above steps.
[0038]
(Step of FIG. 3A)
A substrate 26 made of, for example, Cu is prepared or prepared as a bump formation layer.
[0039]
(Step of FIG. 3B)
Using the bump forming layer 26 as a power supply, a Ni film (for example, 2 μm in thickness) 28 and a Cu film (for example, 10 μm in thickness) 29 are sequentially laminated on the bump forming layer 26 by electroplating. As a result, a laminate having a structure in which the Ni film 28 having a different etching resistance from the bump forming layer 26 is in contact with the bump forming layer 26 made of Cu is obtained. The Ni film 28 and the Cu film 29 function as the conductor 27 for forming the second conductor pattern.
[0040]
(Step of FIG. 3C)
After an etching resist (not shown) is formed on the bump forming layer 26, the bump forming layer 26 is selectively etched using the etching resist as a mask. For example, wet etching is performed using an ammonia-based etchant that does not dissolve Ni but dissolves Cu. By this etching, a conductive bump 26a is formed on the conductor 27.
[0041]
(Step of FIG. 3D)
The resin 30 is applied on the conductor 27 so as to fill the space between the conductive bumps 26a. Thereafter, the resin 30 is flattened to expose the front end surface of the conductive bump 26a.
[0042]
(Step of FIG. 5A)
The first conductive pattern 24 obtained in the above step is bonded together with the transfer support 21 to the conductive bump 26a, and hot pressed. Thereby, the first conductor pattern 24 is electrically connected to the conductive bump 26a. In addition, the resin 30 functions as an adhesive layer at the time of bonding, and stable bonding between the first conductive pattern 24 and the conductive bump 26a is ensured.
[0043]
The bonding may be performed after solder, tin, nickel, gold, silver, or the like is attached to the surface of the tip of the conductive bump 26a. In this case, the wettability and the bondability between the first conductor pattern 24 and the conductive bump 26a can be improved, and the temperature and the load can be reduced at the time of bonding the two.
[0044]
Since the transfer support 21 is made of metal, it has higher strength than a transfer sheet formed of a conventional resin film. Therefore, expansion and contraction and warpage during handling are suppressed, and furthermore, local deformation of the transfer support 21 is suppressed, so that deformation and breakage of the first conductor pattern 24 can be avoided, and the fine pitch first conductor pattern can be avoided. 24 can be appropriately bonded to the conductive bumps 26a with high dimensional accuracy.
[0045]
(Step of FIG. 5B)
After an etching resist (not shown) is formed on the Cu film 29, the Cu film 29 is selectively etched using the etching resist as a mask. For example, wet etching is performed using an ammonia-based etchant that dissolves the Cu film 29 but does not dissolve the Ni film 28.
[0046]
(Step of FIG. 5C)
Using the Cu film 29 patterned into a desired shape as a mask, the Ni film 28 is etched. At this time, the Cu film 29 and the conductive bump 26a made of Cu are not eroded by wet etching using, for example, a hydrogen peroxide-based etchant that dissolves Ni but does not dissolve Cu, and only the Ni film 28 is etched. Is patterned into a desired shape.
[0047]
Through the above steps, a second conductive pattern 27a electrically connected to the conductive bump 26a is obtained. That is, the second conductor pattern 27a is formed by patterning the Ni film 28 and the Cu film 29 into a desired shape.
[0048]
(Step of FIG. 6A)
After applying the resin 31 so as to fill the space between the second conductor patterns 27a, the resin 31 is polished and flattened. By this flattening, the surface of the second conductor pattern 27a (the surface of the Cu film 29) is exposed from the resin 31.
[0049]
When the transfer support 21 is separated from the first conductor pattern 24, the first conductor pattern 24 and the second conductor pattern 27a are electrically connected to each other via the conductive bumps 26a. A multilayer wiring board having a wiring structure is obtained.
[0050]
Specifically, the transfer support 21 is peeled off at the interface between the Cr layer 23a and the Ni / Co layer 23b in the peeling layer 23 shown in FIG. For example, a cut is made in the boundary surface and peeled. The Cr layer 23a and the Ni / Co layer 23b can be easily separated without being diffusion bonded to each other even when subjected to the thermal stress at the time of the hot pressing in FIG. 5A.
[0051]
Although the Ni / Co layer 23b remains on the first conductor pattern 24, the Ni / Co layer 23b is wet-etched with, for example, a hydrogen peroxide-based etchant. Accordingly, only the Ni / Co layer 23b can be removed without eroding the first conductor pattern 24 made of Cu.
[0052]
After that, in the multilayer wiring board obtained as described above, an element or an external terminal is joined to the first conductor pattern 24 or the second conductor pattern 27a as necessary.
[0053]
(Second embodiment)
Next, a method for manufacturing the element mounting board according to the second embodiment of the present invention will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0054]
In the present embodiment, after the above-described steps up to FIG. 6A (however, the transfer support 21 is not peeled off), the following steps are continued.
[0055]
(Step of FIG. 6B)
A plating film 32 is formed on the surface of the second conductor pattern 27a (the surface of the Cu film 29) exposed from the resin 31. Since elements and external terminals are joined to the plating film 32 in a later step, the plating film 32 is formed in order to enhance wettability at the time of joining and improve the joining property. For example, a plating film 32 made of tin, nickel, gold, silver, solder, or the like is formed.
[0056]
The step shown in FIG. 4 is performed independently of the above steps.
[0057]
(Step of FIG. 4A)
An insulating base material 41 made of resin, ceramic, or the like is manufactured or prepared.
[0058]
(Step of FIG. 4B)
An adhesive layer is formed on an insulating base material. The adhesive layer 42 is non-conductive, and further forms an adhesive layer 42 in order to prevent the element from leaking into a void for mounting an element and a through hole for forming an external terminal at the time of bonding to a second conductor pattern 27a to be described later. A material having a low fluidity and a high shape maintaining property is used.
[0059]
(Step of FIG. 4C)
In the insulating base material 41 and the adhesive layer 42, a cavity 43 and through holes 44a and 44b penetrating in the thickness direction are formed. For example, known perforation processing techniques such as processing using a drill or a router, die punching, and laser processing can be applied.
[0060]
(Step of FIG. 7A)
In FIG. 6B, an insulating base material 41 is bonded via a bonding layer 42 to a second conductive pattern 27a having a plating film 32 formed on the surface thereof and a resin 31 filling the space between the second conductive patterns 27a. For example, the bonding is performed by a hot press. At this time, the plating film 32 is positioned so that the gap 43 and the through holes 44a and 44b are located.
[0061]
(Step of FIG. 7B)
The element 36 having the conductive bump 37 is mounted on the plating film 32 exposed in the cavity 43. Thus, the element 36 is electrically connected to the second conductor pattern 27a via the conductive bump 37 and the plating film 32. After mounting the element 36, the voids 43 are filled with the resin 35 to protect the element 36.
[0062]
(Step of FIG. 8A)
The transfer support 21 is separated from the first conductor pattern 24. Specifically, the transfer support 21 is peeled at the boundary between the Cr layer 23a and the Ni / Co layer 23b in the peeling layer 23 shown in FIG. For example, a cut is made in the boundary surface and peeled. The Cr layer 23a and the Ni / Co layer 23b can be easily separated without diffusion bonding to each other even when subjected to the thermal stress during the hot pressing in FIG. 5A and the hot pressing in FIG. 7A.
[0063]
The Ni / Co layer 23b remains on the first conductor pattern 24, and this is wet-etched with, for example, a hydrogen peroxide-based etchant. Accordingly, only the Ni / Co layer 23b can be removed without eroding the first conductor pattern 24 made of Cu.
[0064]
(Step of FIG. 8B)
An insulating protective film 38 is formed so as to cover first conductive pattern 24. Thereafter, when it is necessary to mount another element on the first conductor pattern 24 or to electrically connect to another wiring board, the insulating protective film 38 is selectively opened, and the first protective pattern 38 is opened. Is partially exposed to the outside.
[0065]
(Step of FIG. 9)
External terminals 45a and 45b are formed by filling the through holes 44a and 44b of the insulating base 41 with, for example, solder. The external terminals 45a and 45b are electrically connected to the second conductor pattern 27a via the plating film 32. The external terminals 45a and 45b are not limited to solder bumps, but may be configured with stud bumps, plated bumps, and the like.
[0066]
As described above, the element mounting board 20 in which the element 36 is built in the wiring board having the multilayer (two-layer) wiring is obtained. The element mounting board 20 can be mounted on another wiring board via the external terminals 45a and 45b. Further, another element may be mounted on the first conductor pattern 24. Of course, the number of the built-in elements 36 is not limited to one but may be plural. The element is not limited to a bare chip, but may be a packaged component, a chip resistor, a chip capacitor, or the like.
[0067]
As described above, when the first conductor pattern 24 is formed, the thick and flat support substrate 22 is used as a starting material, and pattern plating by an additive method is not possible with a normal semiconductor interposer substrate or TAB (tape automated bonded) tape. It is possible to form a fine conductor pattern 24 of 10 μm or less as possible. Furthermore, since the support substrate 22 has mechanical strength and material characteristics that do not cause problems in handling properties and dimensional changes, a very thin conductor pattern 24 can be formed with high precision. Finally, since the support substrate 22 is peeled off, a thin multilayer wiring substrate (interposer substrate) or an element mounting substrate (semiconductor package) of 100 μm or less is obtained as a result.
[0068]
In addition, at the time of lamination by the hot press shown in FIG. 5A, since all except the resin 30 functioning as an adhesive layer are metal, there is no restriction on material selection, heating, pressing conditions, and the like.
[0069]
Further, since the conductive bump 26a connecting the first conductive pattern 24 and the second conductive pattern 27a is made of metal (for example, Cu), it has a lower resistance than the conductive paste.
[0070]
Further, in the conventional method for manufacturing a multilayer wiring board shown in FIG. 13, since the multilayering process is a step of alternately stacking the insulating layers and the conductor layers one by one, for example, if a process failure occurs in the upper layer portion, All the steps up to that point are wasted, and the entire wiring board is treated as defective, resulting in poor productivity and low yield.
[0071]
On the other hand, in the present embodiment, the steps of FIG. 1, the steps of FIG. 3, and the step of FIG. 4 are each performed independently, and finally, only the non-defective products are obtained from those obtained in each step. Selected and stacked together to be integrated. Therefore, it is possible to prevent the failure of the entire multi-layer wiring board or the element mounting board due to one process failure, thereby reducing costs by using only non-defective products and shortening the tact time by using a parallel process.
[0072]
(Third embodiment)
Next, a third embodiment of the present invention will be described. Note that the same components as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0073]
In the present embodiment, as shown in FIG. 10, two element mounting substrates 20 obtained in the second embodiment are overlapped and joined to obtain an element mounting substrate 50. External terminals 45 a and 45 b of the other element mounting board 20 are joined to the first conductor pattern 24 of the one element mounting board 20.
[0074]
As a result, an element mounting board 50 in which two elements 36 are built in a multilayer wiring board having four conductive patterns 24 and 27a can be obtained. Of course, it is also possible to further stack the other element mounting boards 20 to further increase the number of layers.
[0075]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. Note that the same components as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0076]
In this embodiment, three or more layers are realized by a method different from that of the third embodiment.
[0077]
That is, as shown in FIG. 11, the conductor 60 with the conductive bump 55 obtained in the same manner as in the step of FIG. 3 is attached to the two-layer wiring board obtained in the step of FIG. 6A.
[0078]
The conductor 60 with the conductive bump 55 is manufactured as follows in the same manner as the process of FIG.
[0079]
First, a substrate made of, for example, Cu is prepared or prepared as a bump formation layer.
Subsequently, the Ni film 56 and the Cu film 57 are sequentially laminated on the bump forming layer by an electroplating method using the bump forming layer as a power feeder. As a result, a laminate having a structure in which the Ni film 56 having a different etching resistance from the bump formation layer is in contact with the bump formation layer made of Cu is obtained. The Ni film 56 and the Cu film 57 constitute a conductor 60 for pattern formation.
[0080]
Next, after forming an etching resist on the bump formation layer, the bump formation layer is selectively etched using the etching resist as a mask. For example, wet etching is performed using an ammonia-based etchant that does not dissolve Ni but dissolves Cu. The conductive bumps 55 are formed on the conductors 60 by this etching.
[0081]
Next, a resin 58 is applied on the conductor 60 so as to fill the space between the conductive bumps 55. After that, the resin 58 is flattened to expose the front end surface of the conductive bump 55.
[0082]
Then, when the conductive bump 55 and the second conductor pattern 27a are opposed to each other, and the resins 58 and 31 are bonded to each other and hot-pressed, the structure shown in FIG. 12 is obtained.
[0083]
Thereafter, as shown in FIG. 12B, by patterning the conductor 60, a conductor pattern 60a is formed. Through the above steps, a multilayer wiring board in which the three-layer conductor patterns 24, 27a, and 60a are electrically connected to each other by the conductive bumps 26a and 55 is obtained. In the case of multi-layering of four or more layers, it can be realized by repeating the steps of FIGS.
[0084]
Although the embodiments of the present invention have been described above, the present invention is, of course, not limited to these, and various modifications can be made based on the technical idea of the present invention.
[0085]
The support substrate of the transfer support is not limited to a metal plate, but may be a glass plate or a semiconductor wafer. In this case, for example, a Ni layer, a Ni—P layer, a Cr layer, or the like is formed as a release layer on the supporting substrate by an electroless plating method or a sputtering method.
[0086]
Further, the release layer is not limited to the configuration shown in FIG. 2, and may be, for example, one layer of a Cr layer, one layer of a Ni layer, or a two-layer structure of a Cr layer and a Ni / Cr layer. , A Cr layer and a Ni layer.
[0087]
The transfer support 21 may be peeled off at any stage after the bonding step shown in FIG. 5A. After the transfer support 21 has been peeled off, an insulating protective film is formed on the first conductor pattern 24 to protect the first conductor pattern 24, and then the remaining steps are performed.
[0088]
【The invention's effect】
As described above, according to the present invention, the first conductive pattern, which is the transfer film transferred from the transfer support, is bonded to the conductive bump formed by selectively etching the bump forming layer. Further, since the second conductor pattern is formed by patterning the conductor laminated on the bump formation layer, the connection between the first and second conductor patterns can be performed through a simple process and through a low-resistance conductive bump. And a device mounting board obtained by mounting an element on the multilayer wiring board.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a step of forming a first conductive pattern in first and second embodiments of the present invention.
FIG. 2 is an enlarged sectional view of a transfer support in FIG.
FIG. 3 is a sectional view showing a step of forming a conductive bump in the first and second embodiments.
FIG. 4 is a cross-sectional view showing a step of forming a space for forming an external terminal and accommodating an element in the second embodiment.
FIG. 5 is a cross-sectional view showing a step of forming a second conductor pattern after laminating those obtained in the steps of FIGS. 1 and 3;
FIG. 6 is a sectional view showing a step following FIG. 5;
FIG. 7 is a sectional view showing a step following FIG. 6;
FIG. 8 is a sectional view showing a step following FIG. 7;
FIG. 9 is a sectional view of a main part of an element mounting board according to a second embodiment of the present invention.
FIG. 10 is a sectional view of a main part of an element mounting board according to a third embodiment of the present invention.
FIG. 11 is a cross-sectional view illustrating a process of manufacturing a multilayer wiring board and an element mounting board according to a fourth embodiment of the present invention.
FIG. 12 is a sectional view showing a step following FIG. 11;
FIG. 13 is a cross-sectional view illustrating a manufacturing process of a conventional multilayer wiring board.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 20 ... Element mounting board, 21 ... Transfer support, 22 ... Support substrate, 23 ... Release layer, 24 ... First conductor pattern, 26 ... Bump formation layer, 26a ... Conductive bump, 27 ... Conductor, 27a ... 2 conductor pattern, 36 ... element, 45a, 45b ... external terminal, 50 ... element mounting board, 55 ... conductive bump, 60 ... conductor, 60a ... third conductor pattern.

Claims (16)

Forming a first conductor pattern on the transfer support;
Forming a conductive bump by selectively etching the conductive bump forming layer,
Bonding the first conductive pattern to the conductive bumps together with the transfer support;
Patterning a conductor laminated on the bump forming layer to form a second conductor pattern;
Separating the transfer support from the first conductor pattern. 2. The conductor according to claim 1, wherein the conductor on which the second conductor pattern is formed has a surface having a different etching resistance from the bump formation layer, and the bump formation layer is laminated on the surface. A method for manufacturing a multilayer wiring board. 2. The multilayer wiring board according to claim 1, wherein the transfer support has conductivity, and the first conductive pattern is formed on the transfer support by pattern plating by an electroplating method. 3. Production method. The method according to claim 1, wherein the transfer support is formed by laminating a release layer on a support substrate. 5. The method according to claim 4, wherein the release layer is formed by laminating a plurality of metal layers. A multilayer wiring board in which a first conductor pattern and a second conductor pattern are connected via conductive bumps,
The first conductor pattern is a transfer film transferred from a transfer support,
The conductive bump is formed by selectively etching a conductive bump forming layer,
The multilayer wiring board according to claim 1, wherein the second conductor pattern is formed by patterning a conductor laminated on the bump formation layer. The multilayer wiring board according to claim 6, wherein the conductive bump is connected to a surface of the conductor having a different etching resistance from the conductive bump. The multilayer wiring board according to claim 6, wherein the first conductor pattern is a plating film obtained by pattern plating the transfer support with an electroplating method. Forming a first conductor pattern on the transfer support;
Forming a conductive bump by selectively etching the conductive bump forming layer,
Bonding the first conductive pattern to the conductive bumps together with the transfer support;
Patterning a conductor laminated on the bump forming layer to form a second conductor pattern;
Separating the transfer support from the first conductor pattern;
Mounting the element by electrically connecting the element to the first and second conductor patterns. 10. The conductor according to claim 9, wherein the conductor on which the second conductor pattern is formed has a surface having a different etching resistance from the bump formation layer, and the bump formation layer is laminated on the surface. A method for manufacturing an element mounting board. The device according to claim 9, wherein the transfer support has conductivity, and the first support pattern is formed on the transfer support by pattern plating using an electroplating method. Production method. The method according to claim 9, wherein the transfer support is formed by laminating a release layer on a support substrate. The method according to claim 12, wherein the release layer is formed by laminating a plurality of metal layers. An element mounting board in which a first conductor pattern and a second conductor pattern are connected via conductive bumps, and an element electrically connected to the first and second conductor patterns is mounted,
The first conductor pattern is a transfer film transferred from a transfer support,
The conductive bump is formed by selectively etching a conductive bump forming layer,
The element mounting board, wherein the second conductor pattern is formed by patterning a conductor laminated on the bump formation layer. The device mounting board according to claim 14, wherein the conductive bump is connected to a surface of the conductor having etching resistance different from that of the conductive bump. The device mounting board according to claim 14, wherein the first conductive pattern is a plating film obtained by pattern plating the transfer support with an electroplating method.

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