JP2004311804A - Wiring board and manufacturing method thereof, and element mount board and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board and a manufacturing method thereof, and an element mount board and a manufacturing method thereof whereby the low profile and the uniformized thickness of an insulating member of a body to be transferred are attained together with a transfer step of a conductor pattern. <P>SOLUTION: The manufacturing method of the wiring board includes the steps of forming a conductor pattern 4 in a first peel-off body 1; closely adhering the conductor pattern 4 to one surface of an uncured insulating material 5, closely adhering a second peel-off body 6 to the other surface, and pressing the insulating material 5 with the first peel-off body 1 and the second peel-off body 6; exfoliating the first peel-off body 1 from the insulating material 5 to transfer the conductor pattern 4 to the insulating material 5; and exfoliating the second peel-off body 6 from the insulating material 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a wiring board having a conductor pattern formed by a transfer method and a method of manufacturing the same, an element mounting board having elements mounted on the wiring board, and a method of manufacturing the same. More particularly, the present invention relates to a wiring board, a method of manufacturing the same, a method of manufacturing the same, a method of manufacturing an element mounting board, and a method of manufacturing the same, in which the thickness of the insulating material can be reduced and the thickness thereof can be controlled at the time of transferring the conductive pattern.
[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 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. Alternatively, an element mounting board incorporating a device such as a semiconductor bare chip to further improve mounting efficiency has been developed.
[0004]
As a method for forming a fine-pitch conductive pattern on a wiring board, a transfer method has been conventionally known. The manufacturing process by this transfer method mainly includes a step of forming a conductor pattern on one surface of a transfer sheet, a step of bonding the conductor pattern to the insulating layer together with the transfer sheet, and a step of separating the transfer sheet and forming the conductor pattern on the insulating layer. And a step of transferring to As this type of conventional technology, for example, there is Patent Document 1.
[0005]
[Patent Document 1]
JP-A-10-107445
[0006]
Hereinafter, description will be made with reference to FIG.
(Step of FIG. 23A)
A via hole 71 is formed in the insulating layer 70. This via hole 71 is formed by, for example, laser processing or micro drilling. Then, conductive paste 72 containing metal powder is filled in via hole 71.
[0007]
(Step of FIG. 23B)
A conductive pattern 74 is formed on a resin transfer sheet 73. For example, after bonding a metal foil to the surface of the transfer sheet 73, patterning a resist on the surface of the metal foil, etching and removing the resist are performed to form the conductor pattern 74.
[0008]
(Step of FIG. 23C)
The conductive pattern 74 is aligned with the via hole 71 filled with the conductive paste 72, and the transfer sheet 73 is attached to the surface of the insulating layer 70. Thereafter, by peeling off the transfer sheet 73, a wiring board having on its surface a conductor pattern 74 connected to the via hole 71 is obtained.
[0009]
A plurality of wiring boards of one unit manufactured in this way are manufactured, and a multilayer wiring board can be manufactured by laminating and pressing them.
[0010]
[Problems to be solved by the invention]
In the conventional example of Patent Document 1, when transferring the conductor pattern 74, the main focus is on joining the conductor pattern 74 and the conductive paste 72, and the via holes 71 and the conductive paste 72 are already formed in the insulating layer 70. For this reason, it is not possible to control the thickness of the insulating layer 70 or adjust the thickness to be uniform in the plane direction. In addition, it is necessary to align the conductor pattern 74 and the via hole 71 at the time of transfer. If the conductor pattern 74 becomes finer, it becomes difficult to cope with this. Alternatively, strict process control is required, resulting in high costs.
[0011]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a wiring board and a method of manufacturing the same, in which the thickness of an insulating material, which is an object to be transferred, can be made uniform and uniform in the process of transferring a conductor pattern. And a method of manufacturing the same.
[0012]
[Means for Solving the Problems]
In the wiring board of the present invention, the conductor pattern transferred from the first release body to one surface of the insulating material narrows the uncured insulating material between the first release body and the second release body, and causes Is transferred by peeling the peeled body from the insulating material.
[0013]
In the method for manufacturing a wiring board according to the present invention, a step of forming a conductive pattern on a first peeled body, a step of bonding a conductive pattern to one surface of an uncured insulating material, and a step of bonding a second peeled body to another surface are performed. A step of narrowing the insulating material between the first peeled body and the second peeled body, a step of peeling the first peeled body from the insulating material and transferring the conductor pattern to the insulating material, Separating the body from the insulating material.
[0014]
As described above, the conductor pattern is pressure-bonded to one surface of the insulating material, and the second peelable body that can be peeled from the insulating material is pressed to the other surface, and is uncured (the semi-cured state of the B stage or the thermal curing). Since the insulating material (including the softened state of the plastic resin and the paste or liquid state) is sandwiched, the thickness of the insulating material can be controlled together with the transfer of the conductor pattern to one surface. By appropriately adjusting the pressurizing condition and the heating condition according to the material of the insulating material, it is possible to obtain a wiring board having a uniform thickness without variation in thickness in the plane direction and a very thin wiring board.
[0015]
For example, when a thermosetting resin is used as the insulating material, the first and second exfoliated bodies are heated in a state where the insulating material is narrowly pressed, and the insulation is performed by heat transfer from the first and second exfoliated bodies. The material can be thermoset. At this time, since the insulating material and the first and second exfoliated bodies are in close contact with each other by surface contact, the insulating material can be uniformly heated and cured in the surface direction, thereby suppressing warpage. Therefore, it is preferable that the first and second exfoliated bodies be made of materials having the same or similar thermal conductivity.
[0016]
In addition, a photocurable resin may be used as the insulating material to cure the insulating material by irradiation with light such as ultraviolet light. Further, the insulating material may be mixed with paper, glass cloth, glass fiber, or the like to improve the strength.
[0017]
Further, the second exfoliated body may be exfoliated while leaving a part of the second exfoliated body as an insulating material, and an interlayer connection hole reaching the conductor pattern may be formed in the insulating material using the remaining second exfoliated body as a mask. Thus, the process can be simplified and the cost can be reduced.
[0018]
The first exfoliated body functions as a support for maintaining the flatness of the 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.
[0019]
The first and second exfoliated bodies are ultimately exfoliated from the insulating material and do not remain. It is preferable to have a release layer for facilitating the release. 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 a dimensional change or deterioration does not occur even after a hot pressing process at about 350 ° C., for example.
[0020]
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.
[0021]
Alternatively, without providing the release layer, the first release body or the second release body may be dissolved and separated from the insulating material.
[0022]
In addition, if the conductive pattern is formed on the first conductive strip by electroplating, a fine conductive pattern can be formed with high precision by using a pattern plating technique based on an additive method.
[0023]
The element mounting substrate according to the present invention is configured such that the uncured insulating material is narrowed by the first peeling body and the second peeling body, and the first peeling body is peeled off from the insulating material. The device is characterized in that the elements are electrically connected and mounted.
[0024]
In the method for manufacturing an element mounting board according to the present invention, a step of forming a conductor pattern on a first peeled body, a step of adhering the conductor pattern to one surface of an uncured insulating material, and a step of adhering the second peeled body to the other surface A step of narrowing the insulating material between the first peeled body and the second peeled body, a step of peeling the first peeled body from the insulating material and transferring the conductor pattern to the insulating material, The method is characterized by including a step of peeling the peeled body from the insulating material and a step of electrically connecting the peeled body to the conductor pattern to mount the element.
[0025]
The conductive pattern can be formed flat on the surface of the insulating material by the insulating material being brought into close contact with the conductive pattern and being narrowed, and even a small element can be mounted with high accuracy.
[0026]
Examples of the element include passive elements such as chip resistors and chip capacitors, and active elements such as semiconductor bare chips and semiconductor package parts.
[0027]
In addition, by attaching a reinforcing material with a recess formed through the thickness direction to an insulating material and mounting the element in the recess, the deformation and warpage of the element mounting board are suppressed and the dimensions are stabilized. And handling properties can be improved.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0029]
(First Embodiment)
1 to 5 show a manufacturing process of the wiring board according to the first embodiment.
[0030]
(Step of FIG. 1A)
For example, a release layer 3 is formed on one surface of a copper foil 2 having a thickness of about 140 μm to produce a first release body 1. The release layer 3 is composed of two metal layers, for example, a Cr layer having a thickness of about 0.01 μm and a (Ni—Co) layer having a thickness of about 0.15 μm. The Cr layer is deposited on the surface of the copper foil 2 by the electroplating method using the copper foil 2 as a power supply, and the (Ni-Co) layer is also formed on the surface of the Cr layer by the electroplating method using the copper foil 2 as a power supply. Is deposited.
[0031]
The Cr layer and the (Ni-Co) layer have a characteristic that they are not metal-joined even at a temperature of, for example, about 350 ° C., and therefore can be easily separated even if they are subjected to a hot press in a later step. In this case, peeling is possible at the boundary between the Cr layer and the (Ni-Co) layer.
[0032]
In addition to the above-described configuration, the release layer 3 may have, for example, a single-layer structure of a Cr layer, a single-layer structure of a Ni layer, a two-layer structure of a Cr layer and a (Ni-Cr) layer, or a two-layer structure of a Cr layer and a Ni layer. It may have a two-layer structure or the like.
[0033]
(Step of FIG. 1B)
A conductive pattern 4 to be transferred to an insulating material in a later step is formed on the first exfoliated body 1 configured as described above. Specifically, first, a plating resist (not shown) patterned into a desired shape is formed on the surface of the release layer 3.
[0034]
Next, the first exfoliated body 1 is immersed in a copper electrolytic bath and connected to the cathode electrode to deposit a copper electroplating film. Thereafter, the plating resist is removed to obtain a conductor pattern 4 made of a copper material.
[0035]
In general, a method of forming a conductive pattern by depositing a conductive film only in a necessary portion by an electroplating method (additive method) is different from a method of removing an unnecessary portion of the conductive film by a wet etching method and patterning (a subtractive method). According to this embodiment, a fine conductor pattern 4 having a line and space of, for example, 10 μm / 10 μm can be formed with high precision.
[0036]
The copper foil 2 occupying most of the entire thickness of the first exfoliated body 1 has a small dimensional change. Therefore, the dimensional change of the conductor pattern 4 during the following process is suppressed, and the dimensional accuracy of the fine conductor pattern 4 is reduced. Can be kept stable.
[0037]
(Steps in FIGS. 2C and D)
This is a step of transferring the conductor pattern 4 formed on the first exfoliated body 1 to the insulating material 5. In this step, in addition to the first stripper 1, a second stripper 6 having the same configuration as the first stripper 1 is used.
[0038]
That is, the second exfoliated body 6 is formed by forming, on one surface of the copper foil 7, an exfoliated layer 8 composed of two metal layers, for example, a Cr layer and a (Ni—Co) layer. In addition, the conductor pattern for transfer is not formed on the second exfoliated body 6.
[0039]
The insulating material 5 is, for example, a film-shaped prepreg in which a glass cloth is impregnated with a varnish-like epoxy resin to be in a semi-cured state of a B stage.
[0040]
The conductor pattern 4 is adhered to one surface of the insulating material 5 and the release layer 8 of the second release body 6 is further adhered to the other surface, so that the first release body 1, the insulating material 5 and the second The exfoliated body 6 is narrowed while being heated between hot plates of a hot press (not shown) (FIG. 2D).
[0041]
Thus, the thickness of the insulating material 5 can be reduced to several μm to several tens μm, and the thickness can be made uniform over the surface. Further, even if the gap between the conductor patterns 4 is minute, the gap can be filled with the insulating material 5 without any gap. Further, the conductor pattern 4 is embedded in the surface of the insulating material 5 so that the surfaces of both the conductor pattern 4 and the insulating material 5 are flush with each other to obtain a flat surface without irregularities.
[0042]
Further, by controlling the pressing pressure and the heating temperature according to the material of the insulating material 5, the thickness of the insulating material 5 can be adjusted to control electrical characteristics such as characteristic impedance.
[0043]
Further, the insulating material 5 is heated by heat transfer from the first and second exfoliated bodies 1 and 6 in a state where both surfaces thereof are in close contact with the first and second exfoliated bodies 1 and 6 which are metal. Is done. Therefore, the insulating material 5 can be heated evenly in the surface direction, and the thermosetting of the resin can be uniformly promoted in the surface direction to suppress the warpage.
[0044]
As the insulating material 5, a material that does not deform or deteriorate by heating to a temperature of about 350 ° C. at which the Cr layer and the (Ni—Co) layer constituting the release layer 3 do not metal-join can be used.
[0045]
For example, a thermosetting resin such as an epoxy resin, a polyimide resin, a phenol resin, and a bismaleimide / triazine resin can be used. In the case of a thermosetting resin, the insulating material 5 is softened at a temperature lower than the thermosetting temperature to obtain a desired thickness or to increase the adhesion to the conductor pattern 4, and then completely heated by further high-temperature heating. Let it cure.
[0046]
Alternatively, a thermoplastic resin such as a liquid crystal polymer, polyetheretherketone, or polyetherimide may be used instead of the thermosetting resin. In this case, after the insulating material 5 is softened by heating, the insulating material 5 can be cured at room temperature without performing high-temperature heating.
[0047]
Further, if another insulating layer having a different property from that of the insulating material 5 is laminated, the insulating layer may be deformed or deteriorated. In this embodiment, the laminated body to be subjected to the hot pressing is This is not the case since the material other than the insulating material 5 is a metal.
[0048]
(Step of FIG. 3E)
When the insulating material 5 is completely cured in the C stage in the hot pressing step, the second peeling member 6 is peeled from the insulating material 5. Specifically, the separation is performed at the boundary between the Cr layer and the (Ni-Co) layer in the separation layer 8. For example, a cut is made in the boundary surface and peeled. Since the hot press is performed at a temperature at which the Cr layer and the (Ni-Co) layer do not have a metal bond, the Cr layer and the (Ni-Co) layer can be easily peeled off even when subjected to the thermal stress of the above process. is there.
[0049]
(Step of FIG. 3F)
In the peeling step, one layer (Ni-Co) layer 8a of the two-layer peeling layer 8 remains on the other surface of the insulating material 5. After a resist pattern (not shown) is formed on the (Ni—Co) layer 8a, the openings 9 are selectively formed by wet etching using the resist pattern as a mask.
[0050]
(Step of FIG. 4G)
Using the (Ni—Co) layer 8a in which the opening 9 is formed as a mask, a portion of the insulating material 5 facing the opening 9 is laser-etched, for example. Thereby, an interlayer connection hole 10 reaching the conductor pattern 4 is formed in the insulating material 5. The interlayer connection hole 10 may be formed not only by laser etching but also by wet etching, dry etching, or drilling.
[0051]
As described above, by using a part of the release layer left on the insulating material 5 when the second release body 6 is peeled off as it is as a mask for forming interlayer connection holes, a step of separately forming a mask for laser etching can be performed. Omission, simplification of the process and cost reduction can be achieved.
[0052]
(Step of FIG. 4H)
Electroplating is performed in a copper electrolytic bath using the first exfoliated body 1 as a power supply body to fill the interlayer connection holes 10 with a copper material and form a panel plating film 11 on the other surface side of the insulating material 5.
[0053]
(Step of FIG. 5I)
After a resist pattern (not shown) is formed on the plating film 11, the (Ni—Co) layer 8 a and the plating film 11 are patterned by wet etching using the resist pattern as a mask to form a conductor pattern 12.
[0054]
(Step of FIG. 5J)
Next, the first exfoliated body 1 is exfoliated from the insulating material 5, and the conductor pattern 4 is transferred to the insulating material 5. Specifically, the peeling is performed at the boundary between the Cr layer and the (Ni-Co) layer in the peeling layer 3. For example, a cut is made in the boundary surface and peeled. Since the above-described heat pressing is performed at a temperature at which the Cr layer and the (Ni-Co) layer do not have a metal bond, the Cr layer and the (Ni-Co) layer can be easily peeled off even when subjected to the thermal stress of the above process. It is.
[0055]
(Step of FIG. 5K)
In the peeling step of the first peeled body 1, one (Ni-Co) layer 3a of the two-layer peeled layer 3 remains on the surface of the insulating material 5, but this (Ni-Co) The layer 3a is removed by wet etching using an etchant that does not dissolve the conductor pattern 4 made of a copper material, thereby exposing the surface of the conductor pattern 4.
[0056]
As a result, the fine-pitch conductive pattern 4 transferred from the first exfoliated body 1 on one surface of the insulating material 5 is formed flat without unevenness on the insulating material 5, and is further connected to the other surface of the insulating material 5 by interlayer connection. A wiring board 17 on which the conductor pattern 12 electrically connected to the conductor pattern 4 via the conductive material filling the hole 10 is obtained.
[0057]
The wiring board 17 is thinned with a uniform thickness in the surface direction by the above-described hot press at the time of transferring the conductor pattern 4, and the occurrence of warpage is suppressed. In addition, since the transfer of the conductor pattern 4 and the uniform thinning of the insulating material 5 are performed in the same step, the number of steps is not increased, and the above-described series of steps can be performed using existing equipment. It is also possible to suppress an increase in costs associated with preparing new equipment.
[0058]
Moreover, since the interlayer connection hole 10 connected to the conductor pattern 4 is formed after the conductor pattern 4 is transferred to the insulating material 5, it is not necessary to perform highly accurate alignment with the insulating material 5 at the time of transferring the conductor pattern 4. Even if the conductor pattern 4 is fine, interlayer connection can be performed with high precision by laser etching.
[0059]
(Second embodiment)
Next, a 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.
[0060]
(Steps in FIGS. 6L and M)
An insulating reinforcing material 13 made of, for example, resin or ceramic is thermocompression-bonded to the wiring board 17 obtained in the first embodiment. On one surface of the reinforcing material 13, an adhesive layer 14 having an insulating property and a low fluidity is formed. Further, the reinforcing member 13 has a recess 15 penetrating in the thickness direction. The plane size of the recess 15 is slightly larger than the plane size of the element to be mounted on the conductor pattern 4 a of the wiring board 17.
[0061]
(Step of FIG. 7N)
A bonding material 16 such as tin, nickel, gold, silver, or solder for increasing wettability and improving bonding properties is supplied or formed on the conductor pattern 4a to be bonded to the element.
[0062]
(Step of FIG. 7O)
The element 20 is arranged in the recess 15 and mounted on the wiring board 17. The conductive bumps 20 a of the element 20 are electrically connected to the conductor patterns 4 a via the bonding material 16. After the mounting of the element 20, the underfill resin 21 is supplied to the recess 15 to protect the joint between the element 20 and the wiring board 17.
[0063]
(Step of FIG. 8)
A conductive bump 22 (solder ball, metal plating bump, metal stud bump, etc.) functioning as an external connection terminal is joined to the conductive pattern 12 exposed on the other surface side of the wiring board 17 to form an element mounting board 23. can get.
[0064]
FIG. 8 is a sectional view taken along the line [8]-[8] in the plan view shown in FIG. The element mounting board 23 shown in FIG. 9 is finally divided into a unit having one element 20 as one unit or a unit having two or more elements 20 as one unit.
[0065]
The reinforcing member 13 existing so as to surround the periphery of the element 20 suppresses the warpage of the element mounting board 23 and improves the handleability, and improves the mounting process to another board via the conductive bump 22. Workability can be improved.
[0066]
In addition, in a method of performing various processes such as peeling of a peeled body, etching of a wiring board, and photolithography after mounting of an element, if a failure occurs in the processing after mounting, even if the element is normal, the entire product is Will be bad. On the other hand, in the present embodiment, after the device 20 is mounted, no processing of the wiring board 17 itself is performed, and only the device 20 is mounted on the already completed wiring substrate 17. Can be used as it is, and the yield can be further improved.
[0067]
(Third embodiment)
Next, a third embodiment of the present invention will be described. The same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0068]
1A to 5I, a laminated body of the first exfoliated body 1, the conductive pattern 4, the insulating material 5, and the conductive pattern 12 'is obtained as shown in FIG. 10A.
[0069]
(Steps in FIGS. 10A and 10B)
Then, the insulating material 25 is narrowed by the laminated body and the second exfoliated body 26. The second release body 26 is formed by forming a release layer 28 composed of two metal layers, for example, a Cr layer and a (Ni—Co) layer on one surface of a copper foil 27. Note that no transfer conductor pattern is formed on the second exfoliated body 26.
[0070]
The insulating material 25 is, for example, a film-shaped prepreg in which a glass cloth is impregnated with a varnish-like epoxy resin and is in a semi-cured state of a B stage.
[0071]
The conductor pattern 12 ′ is adhered to one surface of the insulating material 25, and the release layer 28 of the second release body 26 is further adhered to the other surface, so that the first release body 1, the insulating material 25 and the second The pressure is reduced while heating the exfoliated body 26 between hot plates of a hot press (not shown) (FIG. 10B).
[0072]
This makes it possible to make the insulating material 25 thin and to make the thickness uniform over the surface direction. Further, even if the gap between the conductor patterns 12 'is minute, the gap can be filled with the insulating material 25 without gap.
[0073]
Further, by controlling the pressing pressure and the heating temperature in accordance with the material of the insulating material 25, the thickness of the insulating material 25 can be adjusted to control electrical characteristics such as characteristic impedance.
[0074]
(Step of FIG. 11C)
When the insulating material 25 is completely cured in the C stage in the hot pressing step, the second peeling member 26 is peeled from the insulating material 25. Specifically, the separation is performed at the boundary between the Cr layer and the (Ni-Co) layer in the separation layer 28. For example, a cut is made in the boundary surface and peeled. Since the hot press is performed at a temperature at which the Cr layer and the (Ni-Co) layer do not have a metal bond, the Cr layer and the (Ni-Co) layer can be easily peeled off even when subjected to the thermal stress of the above process. is there.
[0075]
(Step of FIG. 11D)
In the peeling step, one layer (Ni-Co) layer 28a of the peeling layer 28 having the two-layer structure remains on the other surface of the insulating material 25. After a resist pattern (not shown) is formed on the (Ni-Co) layer 28a, openings 29 are selectively formed by wet etching using the resist pattern as a mask.
[0076]
(Step of FIG. 12E)
Using the (Ni-Co) layer 28a in which the opening 29 is formed as a mask, a portion of the insulating material 25 facing the opening 29 is laser-etched, for example. Thereby, the interlayer connection hole 30 reaching the conductor pattern 12 ′ is formed in the insulating material 25. The interlayer connection hole 30 may be formed not only by laser etching but also by wet etching, dry etching, or drilling.
[0077]
(Step of FIG. 12F)
Electroplating is performed in a copper electrolytic bath using the first exfoliated body 1 as a power supply body to fill the interlayer connection holes 30 with a copper material and form a panel plating film 31 on the other surface side of the insulating material 25.
[0078]
(Step of FIG. 13G)
After a resist pattern (not shown) is formed on the plating film 31, the (Ni—Co) layer 28 a and the plating film 31 are patterned by wet etching using the resist pattern as a mask to form the conductor pattern 32.
[0079]
(Step of FIG. 13H)
Next, the first exfoliated body 1 is exfoliated from the insulating material 5, and the conductor pattern 4 is transferred to the insulating material 5. Specifically, the peeling is performed at the boundary between the Cr layer and the (Ni-Co) layer in the peeling layer 3. For example, a cut is made in the boundary surface and peeled. Since the above-described heat pressing is performed at a temperature at which the Cr layer and the (Ni-Co) layer do not have a metal bond, the Cr layer and the (Ni-Co) layer can be easily peeled off even when subjected to the thermal stress of the above process. It is.
[0080]
(Step of FIG. 13I)
In the peeling step of the first peeled body 1, one (Ni-Co) layer 3a of the two-layer peeled layer 3 remains on the surface of the insulating material 5, but this (Ni-Co) The layer 3a is removed by wet etching using an etchant that does not dissolve the conductor pattern 4 made of a copper material, thereby exposing the surface of the conductor pattern 4.
[0081]
As a result, as shown in FIG. 13I, a wiring board 33 having three layers of conductor patterns 4, 12 ', 32 is obtained. On one surface of the insulating material 5, a fine-pitch conductive pattern 4 transferred from the first exfoliated body 1 is formed flat with respect to the insulating material 5 without unevenness. The conductor pattern 12 'is electrically connected to the conductor pattern 4 via a conductive material filling the interlayer connection hole 10. The conductor pattern 32 is electrically connected to the conductor pattern 12 ′ via a conductive material filling the interlayer connection hole 30.
[0082]
After the step of FIG. 13G, by repeating the same steps starting from FIG. 10A described above on this laminate, a wiring board having a conductor pattern of four or more layers can be manufactured.
[0083]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. The same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0084]
(Step of FIG. 17A)
Similarly to the first embodiment, the release layer 3 is formed on one surface of the copper foil 2 to produce the first release body 1.
[0085]
(Step of FIG. 17B)
A conductive pattern to be transferred to an insulating material in a later step is formed on the first exfoliated body 1. Specifically, first, a plating resist (not shown) patterned into a desired shape is formed on the surface of the release layer 3.
[0086]
Next, the first exfoliated body 1 is immersed in a copper electrolytic bath and connected to the cathode electrode to deposit a copper electroplating film. Thereafter, the plating resist is removed to obtain a conductor pattern 36 made of a copper material.
[0087]
(Steps in FIGS. 18C and 18D)
This is a step of transferring the conductor pattern 36 formed on the first exfoliated body 1 to the insulating material 5. In this step, in addition to the first stripper 1, a second stripper 6 having the same configuration as the first stripper 1 is used.
[0088]
The second release body 6 is formed by forming a release layer 8 composed of two metal layers, for example, a Cr layer and a (Ni—Co) layer on one surface of the copper foil 7. On the surface of the release layer 8, a conductor pattern 37 to be transferred to the other surface of the insulating material 5 is pattern-plated by electroplating.
[0089]
The insulating material 5 is, for example, a film-shaped prepreg in which a glass cloth is impregnated with a varnish-like epoxy resin to be in a semi-cured state of a B stage.
[0090]
The conductor pattern 36 formed on the first exfoliated body 1 is adhered to one surface of the insulating material 5 and the conductor pattern 37 formed on the second exfoliated body 6 is adhered to the other surface. The exfoliated body 1, the insulating material 5, and the second exfoliated body 6 are narrowed while being heated between hot plates of a hot press (not shown) (FIG. 18D).
[0091]
This makes it possible to make the insulating material 5 thin and to make the thickness uniform over the surface direction. Further, by controlling the pressing pressure and the heating temperature according to the material of the insulating material 5, the thickness of the insulating material 5 can be adjusted to control electrical characteristics such as characteristic impedance.
[0092]
Further, the insulating material 5 is heated by heat transfer from the first and second exfoliated bodies 1 and 6 in a state where both surfaces thereof are in close contact with the first and second exfoliated bodies 1 and 6 which are metal. Is done. Therefore, the insulating material 5 can be heated evenly in the surface direction, and the thermosetting of the resin can be uniformly promoted in the surface direction to suppress the warpage.
[0093]
(Step of FIG. 19E)
When the insulating material 5 is completely cured in the C stage in the hot pressing step, the second peeling member 6 is peeled from the insulating material 5. Specifically, the separation is performed at the boundary between the Cr layer and the (Ni-Co) layer in the separation layer 8. For example, a cut is made in the boundary surface and peeled. Since the hot press is performed at a temperature at which the Cr layer and the (Ni-Co) layer do not have a metal bond, the Cr layer and the (Ni-Co) layer can be easily peeled off even when subjected to the thermal stress of the above process. is there.
[0094]
(Step of FIG. 19F)
In the peeling step, the conductor pattern 37 and one layer (Ni-Co) layer 8a of the two-layer peeled layer 8 remain on the other surface of the insulating material 5. After a resist pattern (not shown) is formed on the surface of the (Ni-Co) layer 8a, openings 9 are selectively formed by wet etching using the resist pattern as a mask.
[0095]
(Step of FIG. 20G)
Using the (Ni—Co) layer 8a in which the opening 9 is formed as a mask, a portion of the insulating material 5 facing the opening 9 is laser-etched, for example. Thereby, the interlayer connection hole 10 reaching the conductor pattern 36 is formed in the insulating material 5. The interlayer connection hole 10 may be formed not only by laser etching but also by wet etching, dry etching, or drilling.
[0096]
(Step of FIG. 20H)
Electroplating is performed in a copper electrolytic bath using the first exfoliated body 1 as a power supply body to fill the interlayer connection holes 10 with a copper material and form a panel plating film 11 on the surface of the (Ni-Co) layer 8a. I do.
[0097]
(Step of FIG. 21I)
After forming a resist pattern (not shown) on the plating film 11, the (Ni—Co) layer 8 a and the plating film 11 are patterned by wet etching using the resist pattern as a mask to form a conductor pattern 38.
[0098]
(Step of FIG. 21J)
Next, the first exfoliated body 1 is exfoliated from the insulating material 5, and the conductor pattern 36 is transferred to the insulating material 5. Specifically, the peeling is performed at the boundary between the Cr layer and the (Ni-Co) layer in the peeling layer 3. For example, a cut is made in the boundary surface and peeled. Since the above-described heat pressing is performed at a temperature at which the Cr layer and the (Ni-Co) layer do not have a metal bond, the Cr layer and the (Ni-Co) layer can be easily peeled off even when subjected to the thermal stress of the above process. It is.
[0099]
(Step of FIG. 21K)
In the peeling step of the first peeled body 1, one (Ni-Co) layer 3a of the two-layer peeled layer 3 remains on the surface of the insulating material 5, but this (Ni-Co) The layer 3a is removed by wet etching using an etching solution that does not dissolve the conductor pattern 36 made of a copper material, thereby exposing the surface of the conductor pattern 36.
[0100]
Thereby, the wiring board 39 shown in FIG. 21K is obtained. On one surface of the insulating material 5, a fine-pitch conductive pattern 36 transferred from the first exfoliated body 1 is formed flat with no unevenness on the insulating material 5. On the other surface side of the insulating material 5, conductive patterns 37, 38 electrically connected to the conductive pattern 4 via a conductive material filling the interlayer connection hole 10 are formed.
[0101]
The wiring board 39 is thinned by the above-described hot press with a uniform thickness in the surface direction, and the occurrence of warpage is suppressed. In addition, since the transfer of the conductor patterns 36 and 37 and the uniform thinning of the insulating material 5 are performed in the same step, the number of steps is not increased, and the series of steps described above can be performed using existing equipment. Therefore, it is possible to suppress an increase in cost associated with the preparation of new equipment.
[0102]
(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. The same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. This embodiment differs from the first embodiment in the heat press step at the time of transfer. That is, instead of using the film-like insulating material 5 as shown in FIG. 2, a paste-like insulating material 34 is used as shown in FIG.
[0103]
(Step of FIG. 14A)
For example, a paste-like polyimide resin 34 is applied on the surface of the first exfoliated body 1 on which the conductive pattern 4 is formed, by spin coating, spraying, or the like.
[0104]
(Step of FIG. 14B)
Thereafter, the release layer 8 of the second release body 6 is brought into close contact with the surface of the polyimide resin 34, and the polyimide resin 34 is sandwiched between the first and second release bodies 1 and 6 and heated. The polyimide resin 34 is cured by receiving the heat transfer via the first and second exfoliated bodies 1 and 6, and becomes an insulating material 34 'having a small thickness and a uniform thickness. Thereafter, the process proceeds in the same manner as in the first embodiment.
[0105]
(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. The same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0106]
In this embodiment, as shown in FIG. 15, an element mounting board 51 is formed by mounting elements 20 and 53 on both sides of a wiring board 52 manufactured in the same manner as in the first embodiment. You.
[0107]
That is, the element 53 is bonded to the conductor pattern 55 formed on the other surface of the insulating material 5 by interlayer connection with the conductor pattern 4 formed by transfer on one surface of the insulating material 5 via the conductive bump 53a. ing.
[0108]
A through-hole reaching the conductor pattern 4 is formed in the reinforcing material 13 attached to the insulating material 5, and the through-hole is filled with a conductive material such as solder, and a conductive bump 54 functioning as an external connection terminal is formed. Is formed. The number of elements is not limited to two, and three or more elements may be mounted on the wiring board 52.
[0109]
(Seventh embodiment)
Next, a seventh embodiment of the present invention will be described. The same components as those in the above embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0110]
As shown in FIG. 16, the element mounting board of the present embodiment has a structure in which three element mounting boards 60a to 60c are stacked. Each of the element mounting boards 60a, 60b, and 60c is obtained by the same process as in the first and second embodiments.
[0111]
A through hole reaching the conductor pattern 4 is formed in the reinforcing member 13 of the element mounting board 60a, and the through hole is filled with a conductive material 61 such as solder. The conductive bumps 22 of the element mounting board 60b are joined to the conductive material 61. A through hole reaching the conductor pattern 4 is also formed in the reinforcing member 13 of the element mounting board 60b, and the through hole is filled with a conductive material 61 such as solder. The conductive bumps 22 of the element mounting board 60c are joined to the conductive material 61. Further, by repeating this, a laminated structure of four or more layers can be obtained.
[0112]
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.
[0113]
When the insulating material is narrowed with the first and second peeling members, as shown in FIG. 22, the film-like insulating material fed between the pair of guide rollers 41a and 41b is separated from the first and second peeling members. In a state sandwiched between the bodies 1 and 6, the pressure may be narrowed by the pair of pressing rollers 40a and 40b. Alternatively, a roll coating method in which a liquid resin is applied onto the conductive pattern using a roller may be used.
[0114]
Also, if the insulating material is narrowed under vacuum between the first and second exfoliated bodies, the air at the close contact portion is completely released, thereby suppressing the generation of voids. Can be improved.
[0115]
The conductor pattern and the conductor material for interlayer connection are not limited to copper, and other metals and alloys such as copper alloy, gold, silver, and aluminum may be used.
[0116]
【The invention's effect】
As described above, according to the present invention, when transferring a conductor pattern, the conductor pattern formed on the first exfoliated body is brought into close contact with one surface of the uncured insulating material, and the second surface is adhered to the other surface. Since the peeled body is closely adhered and the insulating material is narrowed between the first peeled body and the second peeled body, the first peeled body is peeled from the insulating material, and the conductor pattern is transferred to the insulating material. The thickness of the insulating material can be optimized and made uniform without increasing the number of steps. As a result, it is possible to improve the quality and reduce the thickness of the wiring board or the element mounting board.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a manufacturing process of a wiring board according to a first embodiment of the present invention.
FIG. 2 is a manufacturing process sectional view following FIG. 1;
FIG. 3 is a sectional view of the manufacturing process following FIG. 2;
FIG. 4 is a manufacturing process sectional view following FIG. 3;
FIG. 5 is a sectional view of the manufacturing process following FIG. 4;
FIG. 6 is a cross-sectional view of a manufacturing step of the element mounting board according to the second embodiment, which is performed subsequent to FIG. 5;
FIG. 7 is a sectional view of the manufacturing process following FIG. 6;
FIG. 8 is a sectional view of an element mounting board according to a second embodiment.
FIG. 9 is a plan view of the element mounting board.
FIG. 10 is a cross-sectional view showing a manufacturing step of the wiring substrate according to the third embodiment.
FIG. 11 is a manufacturing process sectional view following FIG. 10;
FIG. 12 is a sectional view of the manufacturing process following FIG. 11;
FIG. 13 is a manufacturing process sectional view following FIG. 12;
FIG. 14 is a cross-sectional view showing a manufacturing step of the wiring substrate according to the fifth embodiment.
FIG. 15 is a sectional view of an element mounting board according to a sixth embodiment.
FIG. 16 is a sectional view of an element mounting board according to a seventh embodiment.
FIG. 17 is a cross-sectional view illustrating a manufacturing step of the wiring substrate according to the fourth embodiment;
FIG. 18 is a sectional view of the manufacturing process, following FIG. 17;
FIG. 19 is a manufacturing process sectional view following FIG. 18;
FIG. 20 is a sectional view of the manufacturing process, following FIG. 19;
FIG. 21 is a sectional view of the manufacturing process, following FIG. 20;
FIG. 22 is a schematic view showing a modification of the transfer step.
FIG. 23 is a cross-sectional view illustrating a manufacturing process of a conventional wiring board.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st exfoliation body, 2 ... Copper foil, 3 ... Exfoliation layer, 4 ... Conductor pattern, 5 ... Insulation material, 6 ... Second exfoliation body, 7 ... Copper foil, 8 ... Exfoliation layer, 10 ... Interlayer connection Holes, 12: conductor pattern, 13: reinforcing material, 14: adhesive layer, 15: recess, 17: wiring board, 20: element, 22: external terminal, 23: element mounting board, 25: insulating material, 26: first 2 peeled body, 27 copper foil, 28 peeled layer, 30 interlayer connection hole, 32 conductor pattern, 33 wiring board, 34 insulating material, 36 conductor pattern, 37 conductor pattern, 38 conductor pattern 39, a wiring board, 51, an element mounting board, 52, a wiring board, 53, an element, 55, a conductor pattern, 60a to 60c, an element mounting board.

Claims (9)

A wiring board having, on one surface of an insulating material, a conductor pattern transferred from a first peelable body that can be peeled off from the insulating material,
The conductor pattern narrows the uncured insulating material with the first peeled body and a second peelable body that can be peeled from the insulating material, and separates the first peeled body from the insulating material. A wiring substrate, which is transferred to the insulating material by peeling. Forming a conductor pattern on the first exfoliated body;
The conductor pattern is brought into close contact with one surface of the uncured insulating material, and the second exfoliated body is adhered to the other surface, and the insulating material is narrowed by the first exfoliated body and the second exfoliated body. Process and
A step of transferring the conductor pattern to the insulating material by peeling the first peeled body from the insulating material;
Separating the second strip from the insulating material. The second exfoliated body is exfoliated from the insulating material while leaving a part thereof in the insulating material,
3. The method of manufacturing a wiring board according to claim 2, further comprising the step of forming an interlayer connection hole reaching the conductor pattern in the insulating material using the second exfoliated body remaining on the insulating material as a mask. Method. The method according to claim 1, wherein the first and second exfoliated bodies are heated in a state where the insulating material is narrowly pressed, and the insulating material is thermoset by heat transfer from the first and second exfoliated bodies. 3. The method for manufacturing a wiring board according to item 2. 3. The method according to claim 2, wherein the conductive pattern is formed on the first conductive body by electroplating. An element substrate having, on one surface of an insulating material, a conductor pattern transferred from a first exfoliating body that can be peeled off from the insulating material, and an element electrically connected to the conductor pattern mounted thereon. ,
The conductor pattern narrows the uncured insulating material with the first peeled body and a second peelable body that can be peeled off from the insulating material, and presses the first peeled body from the insulating material. An element mounting substrate, which is transferred to the insulating material by peeling. The device mounting board according to claim 6, wherein a reinforcing material bonded to the insulating material surrounds the periphery of the device. Forming a conductor pattern on the first exfoliated body;
The conductor pattern is brought into close contact with one surface of the uncured insulating material, and the second exfoliated body is adhered to the other surface, and the insulating material is narrowed by the first exfoliated body and the second exfoliated body. Process and
A step of transferring the conductor pattern to the insulating material by peeling the first peeled body from the insulating material;
Peeling the second peeling body from the insulating material;
Mounting the element by electrically connecting the element to the conductor pattern. A step of attaching a reinforcing material having a recess formed therethrough in the thickness direction to the insulating material,
9. The method of manufacturing an element mounting board according to claim 8, further comprising the step of mounting the element while being positioned in the recess.

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