JP2002271020A - Printed wiring board, and built-up wiring board and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a built-up layer with a different thickness through an easy process. SOLUTION: Transfer plates 13 and 13' having conductive pastes 12a and 12a', and 12b and 12b' for wiring which are different in thickness, conductive pastes 12c and 12c' for a via hole, and insulating resin layers 13 and 13' are laminated on an internal layer wiring board IC while heated and pressed, to transfer the conductive pastes 12a and 12a', and 12b and 12b' for wiring, conductive pastes 12c and 12c' for the via hole, and insulating resin layers 14 and 14' to the top and reverse surface of the internal layer wiring board IC.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board, a build-up wiring board and a method for manufacturing the same, and more particularly, to a method suitable for manufacturing a high-density multilayer printed wiring board.

[0002]

2. Description of the Related Art As electronic devices become smaller and lighter, build-up multilayer printed wiring boards having various via hole structures are used. Here, methods for manufacturing the build-up multilayer printed wiring board mainly include a method using laser processing and a method using a photosensitive resin.

In the method using laser processing, an insulating resin layer is formed on an inner wiring board serving as a base, and via holes are formed at predetermined positions in the insulating resin layer by laser irradiation. Then, after roughening the surface of the insulating resin layer, an electroless copper plating and an electroless copper plating are sequentially performed to form an interlayer conductive layer for making an electrical connection with the inner wiring board on the side wall of the via hole. Then, an outer conductive layer is formed on the surface of the insulating resin layer. Then, an outer wiring layer is formed by patterning the outer conductive layer.

On the other hand, in a method using a photosensitive resin, an insulating resin layer is formed of a photosensitive resin, and the photosensitive resin is exposed and exposed.
By developing, via holes are formed at predetermined positions of the insulating resin layer.

[0005]

However, in the conventional method of manufacturing a build-up multilayer printed wiring board, a plating process is used to form an outer wiring layer and an interlayer wiring layer. For this reason, there was a problem that bath management was required and the manufacturing process became complicated.

In the method of forming via holes by laser irradiation, the number of processed holes increases due to the increase in density.
There is a problem that the process time becomes long.

Further, with the reduction in the diameter of the via hole, a resin residue remains at the bottom of the via hole when the via hole is formed, and this resin residue cannot be completely removed by desmearing before plating, so that the electrical connection between the inner and outer conductive layers is made. There was a problem of becoming defective. On the other hand, when plasma treatment is performed to completely remove the resin residue, there is a problem that the treatment cost increases and the cost increases.

In the conventional printed wiring board, it is necessary to increase the width of the wiring pattern in order to improve the propagation speed of the wiring, and to increase the thickness of the insulating layer in order to improve the insulating characteristics. It is necessary to improve the electrical characteristics of the printed wiring board, and there is a problem in that it goes against the high density of the printed wiring board.

Accordingly, a first object of the present invention is to provide a build-up wiring board capable of manufacturing build-up layers having different thicknesses of wiring layers by simple steps, and a method of manufacturing the same.

A second object of the present invention is to provide a printed wiring board capable of increasing the density without deteriorating the electrical characteristics.

[0011]

According to the first aspect of the present invention, an insulating resin layer having a wiring pattern and a via pattern having two or more thicknesses embedded therein is transferred to a transfer plate. Forming a build-up layer by transferring an insulating resin layer in which the wiring pattern and the via pattern are embedded onto an inner wiring layer.

Thus, the thickness of the conductor can be changed only by changing the depth of the recess in which the conductor is embedded, and a wiring pattern and a via pattern having two or more thicknesses can be easily formed. .

Further, by copying the wiring pattern and the via pattern embedded in the concave portion onto the inner wiring layer via the transfer plate, the interlayer insulation of the wiring pattern can be performed by utilizing the thickness difference between the via pattern and the wiring pattern. In addition to this, it is possible to establish interlayer conduction of the via pattern. As a result, it becomes possible to collectively form a wiring pattern and a via pattern having a thickness of 2 or more, and it is not necessary to perform drilling or plating of an insulating layer. Can be simplified, and the electrical characteristics of the build-up wiring board can be improved while increasing the density.

According to the second aspect of the present invention, a step of filling a conductive paste into a multi-stage excavated concave plate corresponding to a wiring pattern and a via pattern having a thickness of 2 or more; Transferring the filled conductive paste onto a transfer plate; forming an insulating resin layer on the transfer plate onto which the conductive paste has been transferred; and forming the conductive paste and the insulating resin layer. A step of transferring the conductive paste and the insulating resin onto the lower wiring layer by bonding the transfer plate to the lower wiring layer, and a step of removing the transfer plate from the lower wiring layer. It is characterized by the following.

This makes it possible to collectively form a wiring pattern and a via pattern having two or more thicknesses simply by filling the concave portion with the conductive paste, and once the concave portion is formed, The concave plate can be used over and over again. Therefore, it is not necessary to form a pattern for each printed circuit board, so that the thickness of the pattern of the build-up layer can be easily changed, and the manufacturing process of the build-up layer can be simplified. Also, once the conductive paste filled in the concave plate is transferred onto the transfer plate, the conductive paste is projected onto the transfer plate, and the insulating resin is applied on the transfer plate. Can be embedded in an insulating resin, and by simply transferring the conductive paste on the transfer plate onto the inner substrate, utilizing the difference in the thickness of the conductive paste, a wiring having a thickness of 2 or more Insulation of the pattern and conduction of the via pattern can be performed collectively.

According to a third aspect of the present invention, a step of forming a wiring pattern and a via pattern having a thickness of 2 or more on a transfer plate, and the step of forming the wiring pattern and the via pattern formed on the transfer plate. Forming a build-up layer by transferring via an insulating layer.

[0017] Thus, wirings and vias having different thicknesses can be collectively formed only by transferring the wiring pattern and the via pattern, and it is not necessary to perform a drilling process or a plating process on the insulating layer. The manufacturing process of the build-up wiring board can be simplified.

According to the fourth aspect of the present invention, a step of filling a conductive plate into a multi-stage excavated concave plate corresponding to a wiring pattern and a via pattern having a thickness of 2 or more; Transferring the filled conductive paste onto a transfer plate; and bonding the transfer plate to which the conductive paste has been transferred onto a lower wiring layer via an insulating resin sheet, thereby forming a conductive layer corresponding to the wiring pattern. Transferring a paste to the insulating resin sheet, penetrating the insulating resin sheet with a conductive paste corresponding to the via pattern, and removing the transfer plate from the lower wiring layer. Features.

Thus, it is possible to form a wiring pattern and a via pattern having a thickness of 2 or more simply by filling the concave plate with the conductive paste, and transfer the wiring pattern and the via pattern. Alone, it is possible to form a build-up layer having a different thickness of the wiring layer on the inner wiring layer, thereby simplifying the manufacturing process of the build-up layer and improving the electrical characteristics of the build-up wiring board. Can be improved.

Thus, it is possible to collectively form a wiring pattern and a via pattern having a thickness of 2 or more simply by filling the concave plate with the conductive paste, and it is necessary to form a pattern for each printed circuit board. As a result, the manufacturing process of the build-up layer can be simplified, and the electrical characteristics of the build-up wiring board can be improved. Also, once the conductive paste filled in the concave plate is transferred onto the transfer plate, the conductive paste can be projected onto the transfer plate, and the conductive paste on the transfer plate is transferred onto the inner substrate. Just by doing so, the conductive paste can be cut into the insulating resin sheet, and the conductive paste and the insulating resin sheet can be integrated, and wiring can be performed by utilizing the difference in the thickness of the conductive paste. Insulation of the pattern and conduction of the via pattern can be performed collectively.

According to a fifth aspect of the present invention, in the multi-stage drilling, a first blasting process is performed through a mask having an opening corresponding to a wiring pattern having a first thickness. A step of performing a second blasting process through a mask having an opening corresponding to the wiring pattern having a second thickness, and a step of performing a third blasting process through a mask having an opening corresponding to the via pattern And characterized in that:

This makes it possible to easily perform the multi-stage moat processing and to reuse the mask. Therefore, even if the concave plate becomes worn out and becomes unusable, a new concave plate can be formed. Can be easily manufactured.

According to the sixth aspect of the present invention, the build-up layer is formed by transferring, via the insulating layer, the conductive paste on which the wiring pattern and the via pattern having two or more thicknesses are formed. It is characterized by having.

As a result, it is possible to easily realize a via-on-via structure in which the thickness of the wiring layer is different, and it is possible to improve the mounting density while simplifying the manufacturing process.

According to the present invention, the wiring pattern and the via pattern are embedded in the insulating layer, and the surfaces of the wiring pattern and the via pattern coincide with the surface of the insulating layer. It is characterized by.

This makes it possible to suppress the delamination of the interlayer and the land of the outer layer of the via, and to facilitate the surface mounting because the surface is flattened.

According to the eighth aspect of the present invention, wiring patterns having different thicknesses are formed in the same layer.

Accordingly, the thickness of the wiring pattern should be increased in a portion where low resistance is required, such as a clock line or a signal line, and reduced in a portion where a high voltage is applied, such as a power supply line. Can be. For this reason, it is possible to improve the propagation speed of the wiring without increasing the width of the wiring pattern, and it is possible to improve the insulation characteristics without increasing the thickness of the insulating layer. It is possible to increase the density of the printed wiring board without deteriorating the mechanical characteristics.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A build-up wiring board according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a build-up wiring board according to one embodiment of the present invention. In FIG. 1, an inner-layer wiring board IC is provided with an inner-layer insulating substrate 1 in which a through-hole is formed, and an inner-layer copper foil circuit 2 and a plating layer 3 are provided on the upper and lower surfaces of the inner-layer insulating substrate 1 and on the side walls of the through-hole. The through-hole filling paste 4 is buried in the formed through-hole.

Further, build-up layers BU and BD are formed on the upper and lower surfaces of the inner-layer wiring board IC, and each of the build-up layers BU and BD is formed of a wiring conductive paste 12 having a different thickness.
a, 12a ', 12b, 12b' and the conductive paste for vias 12c, 12c ', the surfaces of which are the insulating resin layer 1
The insulating resin layer 1 is made to match the surface of
4, 14 '.

Here, the build-up layers BU and BD on the inner wiring board IC are formed of the conductive pastes 12a, 12a for wiring.
'12b, 12b' and via conductive paste 12
c, 12c '.

That is, the wiring conductive paste 12a,
12a ', 12b' and 12b 'and via conductive pastes 12c and 12c' are formed on a transfer plate, and insulating resin layers 14 and 14 'are further applied on the transfer plate. And
Wiring conductive pastes 12a, 12a'12b, 12b
, The transfer plate on which the via conductive pastes 12c and 12c 'and the insulating resin layers 14 and 14'
C, and paste these conductive pastes 12 for wiring.
a, 12a ', 12b, 12b', via conductive pastes 12c, 12c ', and insulating resin layers 14, 14' are transferred to the inner layer wiring board IC.

Thus, the conductive pastes 12a, 12a ', 12b and 12b' for wiring and the conductive pastes 12c and 12c 'for vias can be transferred to the insulating resin layer 1 only by transferring.
4 and 14 ′ so that the build-up layers BU and BD can be formed collectively, so that the manufacturing process can be simplified, and the bonding strength can be improved and the via land can be improved. Can be suppressed.

The conductive paste 1 for vias is placed in the vias.
Since 2c and 12c 'are filled and electrical connection can be directly performed on vias, a via-on-via structure can be adopted, and it is possible to easily cope with a high density build-up layer. it can.

Further, the conductive pastes for wiring 12a, 1
Since the thicknesses of the conductive pastes 2a '12b and 12b' are different, for example, the conductive pastes 12b and 12b 'for wiring are made to correspond to portions where low resistance is required such as signal lines, and the conductive pastes 12a and 12a' for wiring Can correspond to a portion to which a high voltage is applied, such as a power supply line. Accordingly, in order to suppress the propagation delay, the width of the conductive pastes 12b and 12b 'for wiring is increased, and the insulating resin layers 14 and 14' are formed so as not to impair the interlayer insulating property.
Therefore, it is not necessary to increase the thickness of the circuit board, and the density of the build-up wiring board can be further increased.

Here, the conductive pastes for wiring 12a, 1
2a′12b, 12b ′ and conductive paste 1 for via
2c and 12c 'can be collectively formed only by embedding the conductive paste in the concave portions having different depths. Therefore, wiring patterns having different thicknesses can be easily formed, and the thickness of the wiring pattern can be changed for each wiring pattern without complicated steps.

As the inner-layer wiring board IC, for example,
Glass epoxy substrate, polyimide substrate, bismaleimide azine (BT) substrate, polyphenylene ether (PPE)
A wiring board having a wiring circuit on at least one surface can be used as a base substrate such as a resin substrate such as a substrate) or a copper-clad laminated substrate of such a resin substrate, a ceramic substrate, a metal substrate, or the like.

The insulating resin layers 14 and 14 'may be made of, for example, a thermoplastic resin or a composite of a thermosetting resin and a thermoplastic resin, in addition to a thermosetting resin such as an epoxy resin. As a method of forming the insulating resin layers 14 and 14 ′ on the inner wiring board IC, for example, a method of transferring an insulating resin layer formed on a transfer plate, an insulating resin sheet, a glass fiber cloth, or the like is used. A method of laminating a resin-impregnated sheet (prepreg) impregnated by hot pressing or the like can be used.

As the conductive paste, for example, a paste obtained by mixing conductive particles such as silver particles and copper particles with a thermosetting resin such as an epoxy resin can be used.

Further, in the above-described embodiment, the method of forming the build-up layers BU and BD one by one on the upper and lower surfaces of the inner wiring board BU has been described, but the present invention is not limited to the above-described embodiment. , Build-up layer BU, BD
May be formed in any number of layers, or may be formed only on one side of the inner layer wiring board BU.

FIGS. 2 to 4 are cross-sectional views showing steps of manufacturing a build-up wiring board according to the first embodiment of the present invention.

In FIG. 2A, a through hole is formed in the inner insulating substrate 1, and an inner copper foil circuit 2 and a plating layer 3 are formed on the upper and lower surfaces of the inner insulating substrate 1 and the side walls of the through hole. At the same time, the through-hole filling paste 4 is embedded in the through holes.

On the other hand, in FIG. 2B, the recess forming plate 6 for wiring is arranged on the silicone plate 5. And FIG.
As shown in (c), a blasting process BL1 is performed to form a wiring recess 7 having a depth T1 on the silicone plate 5. Here, an opening 6a corresponding to the wiring pattern having the thickness T1 is formed in the wiring recess forming plate 6, and the blasting process BL1 is performed using the wiring recess forming plate 6 as a mask to form the wiring pattern having the thickness T1. Corresponding wiring recesses 7 can be formed in the silicone plate 5.

As the concave substrate for transfer, an organic material such as Teflon (registered trademark) can be used in addition to the silicone plate 5. In the blast treatment BL1, for example, alumina-based or silicon carbide-based fine particles can be used as an abrasive. As the blasting method, besides an air blasting method in which an abrasive is sprayed at high speed by compressed air to process, a wet blasting method in which an abrasive is mixed into a liquid such as water and sprayed may be used.

Next, as shown in FIG. 2D, the wiring recess forming plate 6 is removed, and the wiring recess forming plate 8 is placed on the silicone plate 5. Then, as shown in FIG.
By performing the blasting process BL2, a wiring recess 9 having a depth T2 is formed in the silicone plate 5. Here, an opening 8a corresponding to the wiring pattern having a thickness T2 is formed in the wiring recess forming plate 8, and the blasting process BL2 is performed using the wiring recess forming plate 8 as a mask to form a wiring pattern having a thickness T2. Corresponding wiring recess 9 is made of silicone plate 5
Can be formed.

Next, as shown in FIG. 2F, the recess forming plate 8 for wiring is removed, and the recess forming plate 10 for via is disposed on the silicone plate 5. Then, as shown in FIG. 2 (g), a blasting process BL3 is performed to form a via recess 11 having a depth T3 in the silicone plate 5. here,
An opening 8a corresponding to the via pattern having a thickness T3 is formed in the via recess forming plate 10, and the via recess forming plate 10 is formed.
By performing blasting process BL3 using
Via recesses 11 corresponding to via patterns having a thickness T3 can be formed in the silicone plate 5.

In the above-described embodiment, the method of using the blasting processes BL1 to BL3 to form the wiring recesses 7 and 9 and the via recess 11 in the silicone plate 5 has been described. Or the like may be used.

Next, as shown in FIG. 3A, the recess forming plate 10 for via is removed, and the conductive paste 12a for wiring is removed.
The wiring recesses 7 and 9 and the via recess 11 are filled with the conductive paste 12b and the via conductive paste 12c, respectively. Thus, wiring patterns and via patterns having different thicknesses can be collectively formed simply by filling the via recess forming plate 10 with the conductive paste.

Next, as shown in FIG. 3B, the silicone plate 5 filled with the wiring conductive pastes 12a and 12b and the via conductive paste 12c is pressed onto the transfer plate 13. Then, as shown in FIG. 3C, the wiring conductive pastes 12a and 12b and the via conductive paste 12c are transferred onto the transfer plate 13. Then 80 ° C
Is placed in an oven set for 30 minutes, and the wiring conductive pastes 12a and 12b and the via conductive paste 1
2c is semi-cured.

Thus, the conductive paste 12 a for wiring having a thickness T 1, the conductive paste 12 b for wiring having a thickness T 2 and the conductive paste 12 c for via having a thickness T 3 are transferred to the transfer plate 1.
The wiring patterns and via patterns having different thicknesses can be collectively formed on the transfer plate 13 simply by filling the silicone plate 5 with the conductive paste and performing the transfer.

As the transfer plate 13, a metal plate such as SUS (stainless steel) or a film such as polyphenylene sulfide can be used.

Further, once the silicone plate 5 on which the wiring recesses 7 and 9 and the via recess 11 are formed is formed, the silicone plate 5 can be reused for the same pattern many times. Therefore, the efficiency of the manufacturing process can be improved. Here, the number of processing is large,
If the silicone plate 5 on which the recesses 9 and the via recesses 11 are formed is severely worn, a master recess may be created and a plurality of recesses may be created therefrom.

Next, as shown in FIG. 3D, an insulating resin layer 14 is formed by applying an epoxy resin on the transfer plate 13 using a curtain coating method or the like, and an oven set at 60 ° C. For 30 minutes to bring the insulating resin layer 14 into the B-stage, so that there is no tack. Here, the conductive pastes 12 a and 12 b for wiring are completely covered with the insulating resin layer 14, and the conductive paste 12 c for via is exposed at the tip from the insulating resin layer 14.

As described above, the upper build-up layer BD before being transferred to the inner wiring board IC of FIG. 1 can be generated by the steps of FIGS. 2B to 3D.

On the other hand, through the same steps as in FIGS. 2B to 3D, as shown in FIG. 3E, the conductive pastes 12a 'and 12b' for wiring and the conductive paste for via The paste 12c 'and the insulating resin layer 14' are formed on the transfer plate 13 '. Thus, the lower buildup layer BU before being transferred to the inner wiring board IC of FIG. 1 can be generated.

Next, as shown in FIG. 4A, conductive pastes 12a and 12b for wiring, conductive paste 1 for via
2c and the transfer plate 13 on which the insulating resin layer 14 is formed are arranged on the upper surface of the inner wiring board IC, and the conductive pastes 12a 'and 12b' for wiring and the conductive paste 1 for via are provided.
Transfer plate 13 on which 2c 'and insulating resin layer 14' are formed
'Is arranged on the lower surface of the inner wiring board IC.

Next, as shown in FIG. 4B, the transfer plates 13, 13 'and the inner-layer wiring board IC are laminated under heat and pressure to form the conductive paste 12 for wiring.
a, 12b, the conductive paste for vias 12c and the insulating resin layer 14 are transferred onto the upper surface of the inner wiring board IC, and
The wiring conductive pastes 12a 'and 12b', the via conductive paste 12c 'and the insulating resin layer 14' are transferred to the lower surface of the inner wiring board IC, and the build-up layers BU and BD are transferred to the upper and lower surfaces of the inner wiring board IC. Form. Then, FIG.
Then, the transfer plates 13 and 13 'are removed as shown in FIG.

Here, the conductive pastes for wiring 12a, 1
2b, 12a 'and 12b' are completely covered with the insulating resin layers 14 and 14 'on the side facing the inner wiring board IC, so that the wiring conductive pastes 12a, 12b, 12a',
Even when 12b 'is laminated on the inner wiring board IC, it is possible to insulate the inner copper foil circuit 2 and the plating layer 3 from each other. In addition, the conductive paste for vias 12c, 12c
Since the front end on the side facing the inner-layer wiring board IC is exposed from the insulating resin layers 14 and 14 ′, it is only necessary to laminate the conductive paste for vias 12 c and 12 c ′ on the inner-layer wiring board IC. In addition, interlayer connection can be performed.

On the other hand, the wiring conductive pastes 12a and 12a
b, 12a ', 12b' and conductive paste 1 for via
The transfer plates 13 and 13 'of 2c and 12c' are on the transfer plate 13,
13 'is in contact with the conductive paste 12 for wiring.
Even when the conductive pastes a, 12b, 12a ', 12b' and the conductive pastes 12c, 12c 'for vias are embedded in the insulating resin layer 12', by removing the transfer plates 13, 13 ', the conductive properties for wiring can be reduced. Pastes 12a, 12b,
12a ', 12b' and Via Conductive Paste 12
The surfaces of c and 12c 'can be exposed. For this reason, the via-on-via structure can be easily realized, and even when the diameter of the via is reduced, the peeling of the via land can be suppressed, and the reliability of the wiring can be improved.

As described above, the wiring conductive paste 12
Filling the wiring recesses 7 and 9 and the via recess 11 with the conductive paste 12a and the via conductive paste 12c makes it possible to easily form wiring patterns and via patterns having different thicknesses. Since it is not necessary to perform the processing for each printed circuit board, the build-up layer BD can be easily formed, and the electrical characteristics of the printed wiring board can be improved.

The wiring conductive pastes 12 a and 12 b filled in the wiring recesses 7 and 9 and the via recess 11.
The conductive paste 12c for vias is transferred to the transfer plate 13, so that the silicone plate 5 on which the concave portions 7, 9 for wiring and the concave portion 11 for via are formed can be used repeatedly. For this reason, it is possible to mass-produce multilayer printed boards having different thicknesses of the wiring layers without performing pattern formation for each printed board only by forming the patterns of the wiring recesses 7 and 9 and the via recess 11 once. In addition, the manufacturing process of the multilayer printed circuit board can be simplified.

The wiring conductive pastes 12a and 12b filled in the wiring recesses 7 and 9 and the via recess 11 are formed.
The conductive paste 12c for vias is temporarily copied onto the transfer plate 13 so that the conductive paste 1
The conductive pastes 2a and 12b and the conductive paste for vias 12c can be projected from the surface of the transfer plate 13, and the conductive pastes for wiring 12a and 12b and the conductive paste for vias 1
The conductive paste 12 for wiring is formed by utilizing the difference in thickness of 2c.
a and 12b can be insulated and the conductive paste for via 12c can be conducted.

In the first embodiment, in order to electrically connect the conductive pastes 12c and 12c 'for vias to the inner wiring board IC, the conductive paste 12c for vias is used.
The method of exposing the tip of 12c 'from the insulating resin layers 14 and 14' has been described.
c, 12c 'may be covered with the insulating resin layers 14, 14'. In this case, the via conductive pastes 12c, 12c 'are pushed away by the via conductive pastes 12c, 12c' during the heating and pressurization, thereby forming the via conductive pastes 12c, 12c.
'Can be electrically connected to the inner-layer wiring board IC.

The insulating resin layers 14 and 14 ′ may be made of an anisotropic conductive resin. In this case, even when the via conductive pastes 12c and 12c 'are completely embedded with the anisotropic conductive resin, the wiring conductive pastes 12a, 12b, 12a' and 12b 'and the via conductive paste 12c are used. , 12c ', it is possible to impart conductivity only to the conductive paste for vias 12c, 12c'.

FIG. 5 is a sectional view showing a manufacturing process of a build-up wiring board according to the second embodiment of the present invention. FIG.
2A to 3C, the wiring conductive pastes 12a, 12b, 12a ', 12b' and via conductive paste are passed through the insulating resin sheets 15, 15 '. Transfer plate 1 on which 12c and 12c 'are formed
3, 13 'are arranged on the upper and lower surfaces of the inner wiring board IC, respectively.

The transfer plates 13, 13 'and the inner wiring board IC are laminated under heat and pressure via insulating resin sheets 15, 15' to form conductive pastes 12a, 12b for wiring and vias for via. Conductive paste 12
c is transferred onto the upper surface of the inner wiring board IC via the insulating resin sheet 15, and the conductive paste 12a '
12b 'and the conductive paste for via 12c' are transferred to the lower surface of the inner wiring board IC via the insulating resin sheet 15 ', and the build-up layers BU, B are formed on the upper and lower surfaces of the inner wiring board IC.
Form D.

At this time, the conductive paste for via 12c, 1
The insulating resin sheets 15 and 15 'are penetrated by 2c', and the conductive pastes 12c and 12c 'for vias are electrically connected to the inner copper foil circuit 2 of the inner wiring board IC. This makes it possible to form the build-up layers BU and BD without applying a resin to the transfer plates 13 and 13 ′ and performing a tack-free process, thereby further reducing the number of steps.

In the second embodiment, the conductive paste for vias 12c, 12c 'is electrically connected to the inner-layer wiring board IC, so that the conductive paste for vias 12c, 12c'
The method of penetrating the insulating resin sheets 15 and 15 'has been described in 12c'. Here, the insulating resin sheets 15, 1
As 5 ', an anisotropic conductive sheet may be used. In this case, the via conductive pastes 12c, 12c '
It is not necessary to penetrate the anisotropic conductive sheet, and the conductive paste for via 12c, 12c, 12c 'and the conductive paste for via 12c, 12c' due to the difference in thickness between the conductive paste for via 12c, 12c ' , 12c 'can be made conductive.

Further, in the above-described embodiment, the description has been made by taking a three-step moat as an example, but the number of steps may be any number.

[0071]

As described above, according to the present invention,
By forming the wirings and vias by transfer, wirings and vias having different thicknesses can be collectively formed, and the manufacturing process of the build-up wiring board can be simplified. The electric characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a build-up wiring board according to an embodiment of the present invention.

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

FIG. 3 is a cross-sectional view illustrating a manufacturing process of the build-up wiring board according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a manufacturing process of the build-up wiring board according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a manufacturing process of a build-up wiring board according to a second embodiment of the present invention.

[Explanation of symbols]

BU Inner layer wiring board BU, BD Build-up layer 1 Inner layer insulating substrate 2 Inner layer copper foil circuit 3 Plating layer 4 Paste to fill through hole 5 Silicone plate 6, 8 Wiring recess forming plate 7, 9 Wiring recess 10 Via recess forming plate 11 Via recess 12a, 12a ', 12b, 12b' Wiring conductive paste 12c, 12c 'Via conductive paste 13, 13' Transfer plate 14, 14 'Insulating resin layer 15, 15' Insulating resin sheet

 ──────────────────────────────────────────────────続 き Continuing on the front page F term (reference) 5E338 AA02 AA03 CD05 EE11 EE31 5E343 AA02 AA12 BB08 BB14 BB21 BB72 DD02 DD56 DD64 ER49 ER52 FF02 FF08 GG06 GG11 GG13 5E346 AA06 AA12 AA15 DD32 DD31 FF18 GG14 GG15 GG19 GG28 HH01 HH32

Claims (8)

[Claims] A step of forming, on a transfer plate, an insulating resin layer in which a wiring pattern and a via pattern having at least two thicknesses are embedded; and forming an insulating resin layer in which the wiring pattern and the via pattern are embedded in an inner layer. Forming a build-up layer by transferring onto a wiring layer. 2. A step of filling a conductive plate into a multi-stage excavated concave plate corresponding to a wiring pattern and a via pattern having a thickness of 2 or more, and applying the conductive paste filled in the concave plate to a transfer plate. Transferring the conductive paste to the transfer plate; and forming an insulating resin layer on the transfer plate to which the conductive paste has been transferred; and pasting the transfer plate having the conductive paste and the insulating resin layer formed on the lower wiring layer. Combining the conductive paste and the insulating resin onto the lower wiring layer; and removing the transfer plate from the lower wiring layer. Production method. Forming a wiring pattern and a via pattern having two or more thicknesses on a transfer plate; and transferring the wiring pattern and the via pattern formed on the transfer plate via an insulating layer. Forming a build-up layer. 4. A step of filling a conductive plate into a multi-stage excavated concave plate corresponding to a wiring pattern and a via pattern having two or more thicknesses, and applying the conductive paste filled in the concave plate to a transfer plate. Transferring the conductive paste onto the lower wiring layer via an insulating resin sheet, and transferring the conductive paste corresponding to the wiring pattern to the insulating resin sheet. And a step of penetrating the insulating resin sheet with a conductive paste corresponding to the via pattern, and a step of removing the transfer plate from the lower wiring layer. . 5. The step of performing a first blasting process through a mask having an opening corresponding to a wiring pattern having a first thickness, and the step of performing multi-stage moat processing. A step of performing a second blast process through a mask having an opening corresponding to the via pattern, and a step of performing a third blast process through a mask having an opening corresponding to the via pattern. 5. The method for manufacturing a build-up wiring board according to 2 or 4. 6. A build-up wiring, wherein a build-up layer is formed by transferring, via an insulating layer, a conductive paste on which a wiring pattern and a via pattern having two or more thicknesses are formed. Board. 7. The build according to claim 6, wherein the wiring pattern and the via pattern are embedded in the insulating layer, and the surfaces of the wiring pattern and the via pattern coincide with the surface of the insulating layer. Up wiring board. 8. A printed wiring board, wherein wiring patterns having different thicknesses are formed in the same layer.