JP2002319763A - Multilayer wiring board and method of manufacturing the same - Google Patents

Abstract

(57) Abstract: A through hole is provided between arbitrary layers of a conventional structure, and an electrical connection can be realized by a conductor filled in the through hole. To provide a multilayer wiring board with improved wiring accommodation. An electric insulating substrate having conductive wiring on at least one of opposing surfaces is laminated, and through holes are provided between the opposing surfaces of the electric insulating substrate, and the through holes are filled. A multilayer wiring board for electrically connecting the conductive wirings 104 between the layers by means of the conductors 103, wherein at least one through hole 102 penetrates over a plurality of layers of the laminated electrically insulating base material 101. The electrical connection between the conductor wirings 104, 104 provided on both sides of the through hole 102 in the penetrating direction is established by the through hole 102.
The process is performed with the conductor 103 filled in.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board in which a plurality of wirings are electrically connected by connecting via inner through holes, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and high performance of electronic equipment, multilayer wiring boards on which semiconductor chips such as LSIs can be mounted at a high density have been supplied at a low cost not only for industrial use but also in the field of consumer equipment. There is a strong demand for it. In such a multilayer wiring board, it is important that a plurality of wiring patterns formed at a fine wiring pitch can be electrically connected with high connection reliability.

In response to the demands of the market, instead of the metal plating conductor on the inner wall of the through hole, which has conventionally been the mainstream of the interlayer connection of the multilayer wiring board, an arbitrary electrode of the multilayer wiring board is replaced with an arbitrary wiring pattern position. In Japanese Patent Application Laid-Open No. 06-26834, there is an inner via hole connection method capable of interlayer connection, that is, an all-layer IVH structure resin multilayer substrate.
No. 5). This is because it is possible to fill the via paste of the multilayer wiring board with a conductive paste as a conductor and connect only necessary layers, and to provide the inner via hole directly under the component land, so that the substrate size is reduced. It is possible to realize miniaturization and high-density mounting. Further, since the electrical connection in the inner via hole uses a conductive paste, stress concentration applied to the via hole can be reduced, and stable electrical connection can be realized against a dimensional change due to a thermal shock or the like.

A multilayer wiring board manufactured by the steps shown in FIGS. 8A to 8I has been conventionally proposed as the all-layer IVH structure resin multilayer board.

[0005] First, reference numeral 701 shown in FIG. 8A denotes an electrically insulating substrate made of a porous base material having a relatively high contraction rate when contracted by pressurization or heating (this property is hereinafter referred to as compressibility). Material.

[0006] As shown in FIG.
No. 01 on both sides facing each other, that is, on both front and back sides forming the plate surface of the electrically insulating base material 701 having a thin plate shape.
02 is attached by lamination. Subsequently, as shown in FIG. 8B, a via hole 703 penetrating all of the electrically insulating substrate 701 and the protective film 702 is formed by a laser or the like. Next, as shown in FIG. 8C, the via holes 703 are filled with a conductive paste 704. Thereafter, the protective films 702 on both sides are peeled off, and in this state, when the foil-like wiring material 705 is laminated and arranged from both sides as shown in FIG. 8D, the state shown in FIG. 8E is obtained.
In the step shown in FIG. 8E, the wiring material 705 is adhered to the electrically insulating base material 701 by heating and pressing. At this time, since the electrically insulating base material 701 has a compressibility, that is, a property of contracting by pressure or the like, it contracts in the thickness direction by heating and pressing. In addition, the conductive paste 704 is compressed in the thickness direction by the heating and pressing process. By this compression, the conductive particles in the conductive paste come into contact with each other at a high density, and at the same time, the electrical connection between the wiring material 705 and the conductive paste 704 is realized. Next, by patterning the wiring material 705 as shown in FIG. 8F, the double-sided wiring substrate 706 is completed. Next, as shown in FIG. 8 (g), on both sides of the double-sided wiring board 706,
8A to 8D, an electrically insulating base material 707 filled with a conductive paste and a wiring material 708 formed in the same steps as those shown in FIGS. The wiring material 708 is heated and pressed in the step shown in FIG. At this time, the double-sided wiring board 706 and the electrically insulating base material 707 are simultaneously bonded. In the heating and pressurizing step, as in the step shown in FIG. 8E, the electrically insulating base material 707 contracts as it is compressed in the thickness direction, and the conductive paste 709 is compressed in the thickness direction.

[0007] By this compression, the conductive paste 709 comes into contact with the wiring material 708 and the wiring 710 on the double-sided wiring board at a high density, and electrical connection is realized. Next, by patterning the wiring material 708 on the surface layer, FIG.
The multilayer wiring board shown in (i) is completed. Here, the example of the four-layer board is shown as the multilayer wiring board, but the number of layers of the multilayer wiring board is not limited to four layers, and is at least two.
It has more than one layer, and can be further multilayered into five or more layers in the same process.

[0008]

FIG. 9 is a cross-sectional view of a multilayer wiring board constructed by the above-described conventional manufacturing method.

According to such a configuration, the amount of accommodated wiring is increased, and through holes, ie, via holes, can be densely arranged. However, when it is necessary to form through holes in series in the thickness direction, the adjacent inner layer lands 801 as shown in part A are used.
Are adjacent to each other, and the adjacent inner-layer lands 801, 80
No wiring can be provided between them.

The inner layer land is formed to have a size of, for example, about 400 μm with respect to the through hole diameter of 200 μm in consideration of a margin of alignment between the through hole and the inner land in a manufacturing process. That is, in general, an inner layer land having a diameter of about twice the diameter of the through-hole is generally provided in consideration of the wiring rule and the productivity balance in consideration of the margin of alignment between the via and the land.

As described above, the actual diameter of the through hole is 200 μm.
m, the inner layer land 801 has a diameter of 400 μm.
m, the distance between adjacent through holes, that is, the pitch, is restricted to a range where the adjacent inner layer lands 801 are not in contact with each other.

In recent years, the number of I / O terminals of a semiconductor has been increasing. For example, an interposer substrate for rewiring thousands of I / O terminals and a motherboard on which such a semiconductor is mounted as a bare chip are provided. It is necessary to increase the wiring density while concentrating the through holes, and in the conventional structure, handling the inner layer lands has been a problem in improving the wiring accommodation.

Therefore, in the conventional structure, as described above, since there are adjacent inner layer lands, in the case where the through holes are formed in series along the layer direction over a plurality of layers, the adjacent through holes are not formed. It was difficult to make the pitch between them narrower.

Further, since the through holes for electrically connecting the layers are conventionally formed with a through hole for each electrically insulating base material in order to connect in series in the layer direction at a specific position, The labor involved in forming the through-holes and filling the conductor was excessively large.

In order to solve the above-mentioned problems, the present invention takes advantage of the feature that a through hole is provided between arbitrary layers of the conventional structure and electrical connection can be realized by a conductor filled in the through hole. It is an object of the present invention to provide a wiring board in which an inner layer has a high wiring accommodation capacity in a through-hole dense portion.

[0016]

In order to achieve the above-mentioned object, a multilayer wiring board according to the present invention comprises an electric insulating base material having conductor wiring on at least one of opposing surfaces, and an electric insulating substrate. A multi-layer wiring board having a through hole penetrating the conductive base material between the opposing surfaces, and performing an electrical connection between layers of the conductive wiring by a conductive paste filled in the through hole, wherein at least one of the The through-hole penetrates over a plurality of layers of the electrically insulating base material laminated, and the through-hole is filled with an electrical connection of the conductor wiring provided on both sides in a penetrating direction of the through-hole. It is configured to be performed with a conductive material.

By forming a through hole penetrating through a plurality of layers of the electrically insulating base material, it is possible to eliminate an inner layer land which has conventionally been required when the through holes are arranged in series in the thickness direction. In addition, it is possible to improve the wiring accommodating property inside the multilayer wiring board, and it is possible to increase the density of wiring in the multilayer wiring board.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multilayer wiring board according to a first aspect of the present invention includes an electric insulating substrate provided with conductor wiring on at least one of the opposing surfaces, and an electric insulating substrate between the opposing surfaces. A multilayer wiring board for electrically connecting between the conductive wiring layers by a conductive paste filled in the through holes, wherein at least one of the through holes is laminated. By penetrating over a plurality of layers of the electrically insulating base material, the electrical connection of the conductor wiring provided on both sides in the penetration direction of the through hole is performed by the conductor filled in the through hole. By forming a through hole that penetrates a plurality of layers of the electrically insulating substrate,
Conventionally, the inner layer land required when arranging through holes in series in the thickness direction can be eliminated, so that the wiring accommodating property in the multilayer wiring board can be improved, and the wiring density in the multilayer wiring board can be increased. Can be achieved.

Further, the present invention eliminates the need for alignment (positioning) of through-holes extending in series in the thickness direction of the multilayer wiring board, thereby improving the efficiency of processing the through-holes and improving the wiring accommodation inside the multilayer wiring board. Can be.

Further, according to the above structure, a plurality of electric insulating substrates are formed with a plurality of electric insulating substrates by forming through holes in each of the substrates, as compared with the conventional case. Since the through holes are provided in the insulating base material, the number of steps can be reduced and the working efficiency can be improved.

According to a second aspect of the present invention, there is provided a multilayer wiring board comprising:
The through hole penetrating a plurality of layers of the electrically insulating substrate,
Since the through-hole is formed avoiding the inner-layer land, there is no inner-layer land in the vicinity of the place where the through-hole is formed. Therefore, it is possible to secure a sufficient wiring accommodation space in the inner layer portion. In addition, the wiring can be accommodated at high density, and the wiring can be provided at high density.

According to a third aspect of the present invention, there is provided a multilayer wiring board comprising:
The through hole penetrating a plurality of layers of the electrically insulating substrate,
It is characterized in that it penetrates through a plurality of electrically insulating substrates including the surface electrically insulating substrate. In a semiconductor bare chip or a semiconductor package having a large number of I / O terminals, terminals are generally arranged in a lattice to accommodate the terminals.
When such a semiconductor and a semiconductor package are mounted on a multilayer wiring board, high-density wiring is required in a wiring layer as close to the surface layer of the multilayer wiring board as possible in order to draw out connection terminals located inside the lattice arrangement. Therefore, in the multilayer wiring board according to the present invention, by providing a through-hole penetrating a plurality of layers of the electrically insulating base material from the surface, it is possible to improve the wiring accommodation in the wiring layer near the surface layer of the multilayer wiring board.

According to a fourth aspect of the present invention, there is provided a multilayer wiring board comprising:
The through hole penetrating a plurality of layers of the electrically insulating substrate,
It is characterized in that it is formed in the shape of a recess. A through hole penetrating through a plurality of layers of electrically insulating base material has a higher aspect ratio than a conventional through hole penetrating through one layer of electrically insulating material. Therefore, by forming the inner wall surface of the through-hole in an inclined state so that the through-hole has a converging shape,
Since the opening is wide, the through hole having a high aspect ratio can be more stably filled with a conductor such as a conductive paste.

According to a fifth aspect of the present invention, there is provided a multilayer wiring board comprising:
It is characterized in that the inner diameter of the through-hole penetrating through the plurality of layers of the electrically insulating substrate increases as the number of layers of the electrically insulating substrate penetrating increases. The aspect ratio of the through hole increases according to the number of layers of the electrically insulating base material that penetrates,
The filling property of the conductor into the through hole is also deteriorated. Therefore, if the diameter of the through hole is increased in accordance with the number of layers of the electrically insulating base material that penetrates to the extent that the wiring accommodating property is not impaired, the filling property into the through hole having a high aspect ratio is improved, and the more stable An electrical connection via the hole is realized.

According to a sixth aspect of the present invention, there is provided a multilayer wiring board comprising:
Since the electrically insulating base material is made of a material having shrinkage, the electrically insulating base material shrinks in a thickness direction in a heating and pressurizing step such as bonding a wiring material, and is performed over a plurality of layers. By forming the through hole, a high-density contact between the conductor filled in the through hole having a high aspect ratio as described above and the wiring material can be achieved, and more reliable electrical connection is realized. .

According to a seventh aspect of the present invention, there is provided a multilayer wiring board comprising:
By having at least one layer of the electrically insulating base material made of the material having the shrinkage property, in a through hole having a high aspect ratio, sufficient compression is performed on a conductor such as a conductive paste filled in the through hole. Is combined with a material having at least one more electrically insulating substrate having shrinkage as an electrically insulating substrate through which a through hole having a high aspect ratio penetrates. The electrically insulating base material having shrinkage shrinks in the thickness direction in the heating and pressurizing step, so that even in a through hole having a high aspect ratio, sufficient compression is applied to the conductor in the through hole, and a wiring material is formed. And high-density contact with the conductor in the through-hole.

[0027] The multilayer wiring board according to claim 8 of the present invention comprises:
By providing the electrically insulating substrate composed of the material having the contraction on the surface layer, the conductive material filled in the through-hole formed through many layers in the final step of laminating the electrically insulating substrate. High-density contact between the body and the wiring material can be realized.

According to a ninth aspect of the present invention, there is provided a multilayer wiring board comprising:
By mixing the electrically insulating base materials having different thicknesses in the laminating direction, the electric insulating base materials having different thicknesses can be formed in the electric insulating base material having a through hole having a high aspect ratio formed through a plurality of layers. The composition ratio of the electrically insulating base material that contracts during the heating and pressurizing step is set high. In other words, even for an electrically insulating base material of the same material, the thicker the material, the larger the shrinkage dimension in the thickness direction during the heating and pressurizing process. By securing the compressibility of the electrically insulating base material during the pressing step, even in a through hole having a high aspect ratio, the conductor in the through hole is sufficiently compressed, and the wiring material and the conductor have a high compression ratio. A dense contact can be realized. In addition, the fact that the electrically insulating base materials having different thicknesses are mixed in the laminating direction means that the two-layered electrically insulating base material is a multilayer wiring board in which the two electrically insulating base materials have different thicknesses. including.

The multilayer wiring board according to claim 10 of the present invention has the thickest electric insulating substrate on the surface layer, so that it can penetrate through many layers in the final step of laminating the electric insulating base material. High-density contact between the conductor filled in the formed through hole and the wiring material can be realized.

[0030] In the multilayer wiring board according to the eleventh aspect of the present invention, at least one layer of the electrically insulating substrate is bonded to at least one of both opposing surfaces thereof for bonding another electrically insulating substrate. By having a film substrate with an agent,
The thickness of the electrically insulating base material can be reduced, and the adhesive can be a contraction layer at the time of applying heat and pressure to the electrically insulating base material. High-density contact between the conductor filled in the hole and the wiring material can be realized. In addition, even if the through-hole is a small-diameter through-hole, it is possible to apply sufficient compression by the adhesive layer having a contractive property, electrical connection through the small-diameter through-hole can be realized, and a higher density can be achieved. A multilayer wiring board can be provided. Furthermore, even when the above-mentioned material having a small shrinkage is used as the electrically insulating base material, the adhesive layer can be shrunk at the time of heating and pressurizing, and the above-mentioned electrical connection can be achieved in the through-hole, that is, the filled conductive material. There is also an advantage that high-density contact between the body and the wiring material can be achieved.

A multilayer wiring board according to a twelfth aspect of the present invention is characterized in that at least one of the conductor wirings electrically connected to the conductor filled in the through-hole penetrating the plurality of layers of the electrically insulating base material. The conductor wiring on one side in the through direction of the through-hole is buried in the electrically insulating base material, so that the wiring is actively buried in the electrically insulating base material during the heating and pressurizing step, The conductor filled in the through-hole by the thickness of the wiring is further compressed, high-density contact between the wiring and the conductor can be realized, and the electrical connection reliability of the through-hole can be improved.

A method for manufacturing a multilayer wiring board according to a thirteenth aspect of the present invention includes the step of forming at least one through hole penetrating a plurality of layers of an electrically insulating base material containing a thermosetting resin; A step of filling the hole with a conductor having conductive particles and a thermosetting resin, and a heating and pressurizing step of heating and pressurizing the electrically insulating base material and the conductor to cure the conductor; The pressure step includes a step of electrically connecting the conductor and the conductor provided on both sides in the penetrating direction of the through hole penetrating the plurality of layers, so that the conductor is serially connected in the thickness direction of the multilayer wiring board. To form a through-hole, it is only necessary to align (align) only an electrically insulating base material having a conductor wiring electrically connected with a conductor filled in the through-hole, and to connect with the conductor wiring. Irrelevant electrical disconnect Alignment on sexual substrates and unnecessary, can provide a higher multilayer wiring substrate having wiring capacity with increasing the efficiency of through-hole processing.

In the method for manufacturing a multilayer wiring board according to a fourteenth aspect of the present invention, in the through hole forming step, through holes having different numbers of electrically insulating base material layers penetrating therethrough are formed at the same time.
By using laser processing or the like in forming the through-hole, processing of the through-hole can be speeded up, and the through-hole can be formed by a manufacturing method with good productivity.

In the method for manufacturing a multilayer wiring board according to a fifteenth aspect of the present invention, in the step of forming a through-hole, through-hole processing is performed simultaneously from both opposing surfaces of the laminated electrically insulating base material, thereby increasing the cost. The through holes can be efficiently formed with positional accuracy, and the through holes can be formed by a manufacturing method with good productivity.

In the method for manufacturing a multilayer wiring board according to a sixteenth aspect of the present invention, in the step of forming the through hole, the through hole is formed so that the conductor wiring is exposed at the bottom of the through hole so as to face the inside of the through hole. Therefore, there is no need to perform through-hole processing in accordance with the wiring pattern so that the wiring material is exposed, and it is not necessary to align and laminate the electrically insulating base material, and the through-hole can be formed with higher positional accuracy. In consideration of the above, the design margin can be reduced, and as a result, a multilayer wiring board having a high wiring accommodation property can be provided.

[0036] In the method for manufacturing a multilayer wiring board according to a seventeenth aspect of the present invention, the electric insulating base material for forming a through hole includes:
By being an electrically insulative substrate in which at least one uncompressed electrically insulative substrate is laminated on at least one surface layer, shrinkage of the electrically insulative substrate in the heating and pressing step can be ensured, and A stable electrical connection in the hole can be realized.

In the method for manufacturing a multilayer wiring board according to claim 18 of the present invention, in the conductor filling step, the conductor is filled simultaneously from both opposing surfaces of the electrically insulating base material.
As compared with the case where only one side of the opposing surface of the electrically insulating substrate is used, the conductor can be filled more efficiently, so that the productivity is improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, in the multilayer wiring board according to the present embodiment, through holes having different numbers of electrically insulating base layers penetrating therethrough are mixed in the multilayer wiring board. However, the present invention includes a case where there are a plurality of through holes penetrating the plurality of electrically insulating base material layers, and all of the through holes have the same number of through layers.

The via hole 102 as a through hole penetrates the three layers of the electrically insulating base material 101, and the conductive wiring on the front and back of the multilayer wiring board is electrically connected to the conductive paste 103 as a conductor filled in the via hole 102. Connected. The via hole 105 provided adjacent to the via hole 102 is similarly configured. Thus, the land 104 of the conductor wiring for electrical connection is provided only on the layer to be electrically connected, and the wiring accommodation space corresponding to the inner layer land 801 in the conventional multilayer wiring board structure shown in FIG. The wiring 106 is accommodated in an inner layer portion between the via hole 102 formed at a narrow pitch and the via hole 105 as a through hole. In this case, the inner layer land does not exist for the via holes 102 and 105 in the electrically insulating base material 101 of the intermediate layer. That is, in this configuration, the via holes 102 and 105 are provided so as to avoid the inner layer lands. It should be noted that the provision of the inner layer land avoiding not only means that the inner layer land is separately provided from the via holes 102 and 105 but is not present in the electrically insulating base material 101, and that the inner layer land is completely present in the electrically insulating base material 101. It means that there is nothing. Further, in addition to the via holes 102 and 105, a via hole 107 penetrating only through one layer of the electrically insulating base material 101, a via hole 108 provided in series with each of the two layers of the electrically insulating base material 101, 101,
109 are provided. Each via hole 107, 108, 1
09 is also filled with the conductive paste 103, and electrical connection is made to the wiring and inner layer lands on both sides.

Next, a manufacturing process of the multilayer wiring board according to the present embodiment will be described with reference to FIGS.

First, the electrically insulating substrate 201 shown in FIG. 2A is characterized by being a compressible porous substrate. That is, by applying compression in the thickness direction of the electrically insulating base material, its size is reduced. The degree of shrinkage can be adjusted by controlling the pores formed in the electrically insulating substrate. As the material of the electrically insulating base material, a material obtained by impregnating a resin with fiber paper such as a woven fabric or a nonwoven fabric can be used. At the time of the impregnation, pores are formed at the same time. If non-woven paper containing aramid fiber as the main component is used as the paper and thermosetting resin containing epoxy as the main component is used as the resin, the pores in the electrically insulating base material can be uniformly and efficiently formed. An insulating substrate having high compressibility, that is, high shrinkage can be obtained. The compressibility of the electrically insulating substrate can be controlled by changing the amount of the resin to be impregnated. That is, if the resin impregnation amount is set small, an electrically insulating base material having a high porosity is formed, and the compressibility can be set high.

A protective film 202 is formed on both sides of the electrically insulating substrate 201, that is, on each of opposing surfaces forming the front and back of the electrically insulating substrate 201. Protective film 202
Is a simple and highly productive manufacturing method in which a film mainly composed of PET or PEN is laminated on both surfaces of the electrically insulating substrate 201 by lamination.

Next, as shown in FIG. 2B, the via hole 2 penetrating through the protective film 202 and the electrically insulating substrate 201 is formed.
03 is formed. The via hole 203 can be formed by punching, drilling, or laser processing. If a carbon dioxide gas laser or a YAG laser is used, a small-diameter through hole can be formed in a short time, and processing with excellent productivity can be realized. .

Subsequently, as shown in FIG. 2C, the via holes 203 are filled with a conductive paste 204.

The conductive paste 204 is composed of metal conductive particles such as copper and silver and a resin component. At this time, the protective film 202 has a role of protecting the conductive paste 204 from adhering to the surface of the electrically insulating base material and a role of ensuring the filling amount of the conductive paste. Since the conductive paste can be filled by printing, it also has an advantage of excellent productivity.

When the protective film 202 is peeled off and the wiring material 205 is laminated on both sides of the electrically insulating substrate, the state shown in FIG. 2D is obtained. Generally, a copper foil is used as the wiring material 205. A copper foil which can roughen the surface and sufficiently secure the adhesion to the electrically insulating substrate is desirable. The filling amount of the conductive paste 204 is ensured by the protective film 202. That is, the conductive paste 204 is in a state of protruding from the surface of the electrically insulating substrate 201 by a height corresponding to the thickness of the protective film 202.

Next, as shown in FIG. 2E, by applying heat and pressure, the wiring material 205 is adhered to both sides of the electrically insulating substrate 201, and the conductive paste 204 is compressed in the thickness direction. Heat cured. In the conductive paste 204 immediately after filling, a large amount of resin components exist between conductive particles in the conductive paste, and sufficient electrical connection is not ensured.
On the other hand, by applying heat and pressure, the electrically insulating substrate 20
1, the thickness of the conductive paste 204 shrinks, and as a result, a compressive force is applied to the conductive paste 204 so that the conductive particles in the conductive paste come into close contact with each other, so that the electrical connection in the conductive paste can be secured. is there.

Next, when the wiring material 205 is patterned by etching, the double-sided wiring substrate 2 shown in FIG.
06 is obtained. Next, on both sides of the double-sided wiring board 206, the electrically insulating substrate 2 having the protective film 208 formed on one side
When the layers 07 are stacked, the state shown in FIG. 2G is obtained. FIG. 2 (h) shows a state in which the electrically insulating base material 207 is attached to the double-sided wiring board 206 by pressing, laminating, or the like. In the attaching step, it is preferable that the electric insulating substrate 207 is attached in an uncured state under the condition that the electric insulating substrate 207 having the compressibility characteristic is temporarily fixed so as not to be compressed. That is, the sticking temperature is desirably a temperature at which the resin component of the electrically insulating base material has tackiness, and the sticking pressure is small enough to suppress air biting during sticking.

Next, as shown in FIG. 2I, through holes having different numbers of layers of the electrically insulating base material penetrating therethrough are processed. The via holes 209 and 212 are in a state in which the wiring material is exposed at the bottom of the through hole, and are realized by adjusting the processing conditions in the laser processing to the conditions in which the wiring material 211 is not processed and only the electrically insulating base material is processed. it can. If the melted resin component or the like remains at the bottom of the through-hole after processing, it can be easily removed by performing excimer laser processing, plasma processing, or the like.

Here, an example is shown in which the wiring material penetrates one layer of the electrically insulating base material as a through hole exposed at the bottom of the hole, but the number of layers of the electrically insulating base material penetrating is limited to this. Instead, by adjusting the laser processing conditions, it is possible to realize processing that penetrates a plurality of layers of the electrically insulating base material.

Via hole 2 as through hole according to the present invention
Reference numeral 10 denotes a through-hole that has been completely drilled without leaving any wiring material at the bottom of the through-hole. Such hole processing can be realized by punching, drilling, or the like. However, if the same laser processing as the processing of the via holes 209 and 212 is used, the processing of the via holes 209 and 212 and the via hole 210 can be continuously performed by the same apparatus. Therefore, it is excellent in productivity.

The laser processing is performed from both sides of the electrically insulating substrate, and the via holes 209 and 212 are formed.
Simultaneous formation of a hole can realize a more productive manufacturing method and eliminates processing position variations due to laser processing equipment transport variations compared to single-side processing, realizing through-hole processing with high positional accuracy. it can.
By realizing the through-hole processing with high positional accuracy in this manner, it becomes possible to process a through-hole such as the via hole 210 from both surfaces without displacement, and it is possible to realize the through-hole processing with higher productivity.

Next, each of the via holes 209, 210, 21
2 is filled with a conductive paste 213 as a conductor, a state shown in FIG. 2 (j) is obtained. This filling is performed by a printing process using a squeegee. However, in the via hole 209 and the via hole 212 where the wiring material is exposed at the bottom of the through hole, bubbles are likely to remain at the bottom of the through hole during filling, so that printing in vacuum or vacuum removal is performed. It is preferable to repeatedly perform printing and filling while performing foam and centrifugal filling from the viewpoint of stably ensuring the filling amount of the conductive paste.

The through hole having a high aspect ratio, such as the via hole 210, is provided with a slope on the wall surface of the through hole in advance, that is, the through hole is formed so that the through hole becomes deeper. When the printing and filling of the conductive paste is performed from the side with the larger size, the filling property of the conductive paste is improved, and the amount of the conductive paste in the through hole can be sufficiently secured. In addition, during squeegee printing, a squeegee printing filling of a conductive paste from both sides of the substrate at the same time is a filling method excellent in productivity.

Next, when the protective film 208 is peeled off and the wiring materials 214 are laminated and arranged from both sides, the state shown in FIG. 2K is obtained. At this time, as in the case of forming the double-sided wiring board, the protective film 208 has a role of protecting the conductive paste from adhering to the surface of the electrically insulating base material and a role of ensuring the filling amount of the conductive paste. In this state, the wiring material 214 is converted into the electrically insulating base material 2 by a heating and pressing process.
07, the state shown in FIG. 2 (l) is obtained.

In this heating and pressing step, the electrically insulating substrate 207 is formed.
Is compressed in the thickness direction, but in order to further compress the conductive paste filled in the through hole 210 having a high aspect ratio, a substrate having a different compression ratio as an electrically insulating substrate,
That is, it is preferable to mix base materials having different shrinkage rates which shrink by heating and pressing, and use a base material having a high compression rate as the electrically insulating base material 207. Thereby, high-density contact between the wiring material and the conductive paste can be realized. Further, it is more preferable to provide a material having a high shrinkage rate on the surface layer, since high-density contact between the wiring material and the conductive paste can be realized.

Further, if base materials having different thicknesses are mixed as the electric insulating base material constituting the multilayer wiring board, and the thickness of the insulating layer of the electric insulating base material 201 is reduced in advance, FIG. The compression efficiency of the conductive paste is increased by the contraction of the electrically insulating base material 207 in the heating and pressurizing step, and high density contact between the conductive paste and the wiring material can be realized even in the through hole 210 having a high aspect ratio.

Further, in the heating and pressing step of FIG. 2E, the electrically insulating base material 201 corresponding to the core is not completely shrunk in the thickness direction. If there is room for the material to shrink, the conductive paste in the through hole having a high aspect ratio such as the via hole 210 can be further compressed.

Next, when the wiring material 214 on the surface is patterned by etching, the four-layer wiring substrate shown in FIG. 2 (m) is completed.

As a method of further compressing the through hole 210 having a high aspect ratio, a multilayer wiring board is manufactured by the manufacturing method shown in FIGS. 3 (a) to 3 (c) instead of FIGS. 2 (k) to 2 (m). Can be formed. In FIG. 3A, in place of the wiring material, a transfer base material in which the conductive wiring 302 is already formed on the support base material 301, for example, the wiring base material obtained in FIG. Laminated and arranged on the laminated base material in the state. Next, as shown in FIG. 3B, the conductor wiring 30 on the transfer substrate is heated and pressed.
2 is embedded in the electrically insulating base material, and the conductive paste in the through hole can be further compressed to the thickness of the wiring, and as a result, the electrical connection in the through hole having a high aspect ratio becomes more stable. . Next, the four-layer wiring board shown in FIG. 3C is completed by removing the supporting base material 301.
If a resin sheet is used as the supporting base material, it can be easily mechanically peeled off. If a metal copper foil such as aluminum is used as the supporting substrate, it can be chemically removed by etching.

The multilayer wiring board according to the present embodiment can also be formed by the manufacturing method shown in FIGS. 4 (a) to 4 (o) and FIGS. 5 (p) to 5 (t). Here, a description of a portion overlapping with the above-described example will be simplified and described.

As shown in FIG. 4A, protective films 402 are formed on both surfaces of an electrically insulating substrate 401 having compressibility, that is, a property of contracting by heating and pressing. Next, when a via hole 403 penetrating through the protective film 402 and the electrically insulating substrate 401 is formed by laser processing or the like, a state shown in FIG. 4B is obtained. Next, FIG.
The conductive paste 404 is filled in the through holes 403 as shown in FIG. The filling of the conductive paste 404 is excellent in productivity when squeegee printing is used. Continue with protective film 402
Is peeled off, and a copper foil is laminated and arranged as the wiring material 405 to obtain the state shown in FIG. Further, the wiring material 405 is adhered to the electrically insulating base material 401 by the heating and pressurizing step, and at the same time, the electrically insulating base material is contracted in the thickness direction, and the conductive paste 404 filled in the through-hole 403 is compressed. The state of e) is obtained. By this compression, high-density contact between the wiring material 405 and the conductive paste 404 is realized, and stable electrical connection is ensured. Subsequently, when the wiring material 405 on one side is patterned by etching, the state shown in FIG. 4F is obtained.

Next, as shown in FIG. 4 (g), an electric insulating base material 407 having a protective film 406 formed on one side is laminated on the wiring material 405 patterned side,
When the electrical insulating base material 407 is attached under the condition of temporary attachment that is not compressed, the state shown in FIG. 4H is obtained.

Next, via holes 408 and via holes 409 as through holes according to the present invention are formed by laser processing from the protective film 406 side. In this laser processing, through holes having different numbers of electrically insulating base layers penetrating therethrough are simultaneously processed, and processing is performed so that the wiring material 405 is exposed at the bottoms of the through holes. Next, when the conductive paste 410 and the conductive paste 411 are filled in the via holes 408 and 409, a state shown in FIG. 4I is obtained. In this filling step, in order to fill the through hole whose bottom is closed with the conductive paste, printing in a vacuum, vacuum defoaming, and centrifugal filling are performed, and repeated printing and filling are performed to reduce the amount of the conductive paste to be filled. It is preferable in terms of ensuring stability.
As for the through-holes having a high aspect ratio, it is desirable that the wall surface of the through-holes be inclined from the viewpoint of filling the conductive paste, as in the example described above.

Next, when the protective film 406 is peeled off and copper foil is laminated and arranged as the wiring material 412, the state shown in FIG. 4K is obtained. Next, as shown in FIG. 4 (l), the wiring material 412 is adhered to the electric insulating base material 407 in the heating and pressing step, and the electric insulating base material 407 contracts in the thickness direction, so that the through holes 408, The conductive paste 410 and 411 inside 409 are compressed, and the wiring material 412 and the conductive paste come into high-density contact.

Next, when the wiring material 412 is patterned by etching, a three-layer wiring substrate shown in FIG. 4M is formed. Subsequently, the steps shown in FIGS. 4 (g) to (l) are repeated, and as shown in FIGS. 4 (n) and 4 (o), the electrically insulating base material 413 having the protective film 414 formed on one side is electrically insulated. 5 are laminated under the condition that the material 413 is not compressed.
As shown in FIG. 5 (p), a process for forming the through holes 416 and 417 is performed, and as shown in FIG.
17 is filled with conductive pastes 418 and 419, the protective film 414 is peeled off as shown in FIG. 5 (r), a wiring material 415 is laminated, and then the wiring material 415 and the electrically insulating substrate are heated and pressed. When the material 413 is bonded, a state shown in FIG. 5 (s) is obtained.

Next, when the wiring material on the front and back surfaces is patterned by etching, the four-layer wiring substrate shown in FIG. 5 (t) is completed.

As described above, the multilayer wiring board according to the present invention can also be formed by a method of laminating the electrically insulating base material on one side of the wiring board one by one. According to such a manufacturing method, it is possible to form a multilayer wiring board without greatly changing a conventional manufacturing process of forming a through hole and filling a conductive paste from only one side of the multilayer wiring board, It is also possible to provide an even number of stacked layers, and it is possible to provide a multilayer wiring board having a sufficient number of layers necessary for accommodating wiring, so that it is not necessary to increase the number of layers more than necessary, thereby reducing material costs.

In the above manufacturing method, only the wiring material on one side is patterned in FIG. 4F, and the wiring material on one side is left unpatterned, and both sides are simultaneously patterned in the final step shown in FIG. Although a method of performing the above-described method has been described, a similar multilayer wiring board configuration can be obtained by patterning the wiring material on both sides in the state of FIG.

Note that, as shown in FIG.
1. A configuration may be adopted in which the number of layers of the electrically insulating base material penetrates the diameter of the through hole of the via hole 502 as the through hole according to the present invention and the via hole 503 as the through hole according to the present invention. Good. If the inner diameter of the through-hole remains the same, the aspect ratio of the through-hole increases according to the number of layers of the electrically insulating base material, and the filling of the through-hole with the conductive paste as a conductor deteriorates. Therefore, if the diameter of the through hole is increased according to the number of layers of the electrically insulating base material that penetrates to the extent that the wiring accommodating property is not impaired, the aspect ratio can be reduced, so that the filling of the conductive paste into the through hole is improved. And
More stable via connection can be realized.

As shown in FIG. 7, via holes 601 and 602 as through holes according to the present invention penetrating a plurality of layers of the electrically insulating base material are formed from the surface layer of the multilayer wiring board, that is, so as to include the surface layer. By forming the via holes 601 and 602, the wiring capacity can be improved in a wiring layer close to the surface layer of the multilayer wiring board. According to such a configuration, I / O
A multilayer wiring board with a high wiring density in a wiring layer close to the surface layer, which is suitable for mounting a semiconductor or a semiconductor package having a large number of terminals can be provided.

Although an example in which a compressible substrate is used as the electrically insulating substrate has been described, an adhesive layer is provided on both sides or one side of the opposite surface of the thin film substrate as the electrically insulating substrate. May be used.

Since the thickness of the electrically insulating base material is reduced, it is possible to sufficiently compress even the small-diameter through-hole by embedding the wiring in the adhesive layer, and the conductor filled in the small-diameter through-hole is filled. , Electrical connection to the conductor wiring can be realized, and a higher-density multilayer wiring board can be provided.

Although a four-layer board has been described as an example of the multi-layer board, the number of layers of the multi-layer board is not limited to four, and the number of layers can be increased by the same process.

[0076]

As described above, according to the present invention, by forming a through-hole penetrating a plurality of layers of an electrically insulating substrate, it is conventionally necessary to arrange the through-holes in series in the thickness direction. Since the inner lands can be eliminated, the wiring accommodating property in the multilayer wiring board can be improved, and the density of wiring in the multilayer wiring board can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first configuration of a multilayer wiring board according to the present invention;

FIGS. 2A to 2M are cross-sectional views illustrating a first method of manufacturing a multilayer wiring board according to the present invention for each of main manufacturing steps;

3A to 3C are cross-sectional views showing main steps in a method for manufacturing a multilayer wiring board according to the present invention using a transfer method.

FIGS. 4A to 4O are cross-sectional views illustrating a second method of manufacturing a multilayer wiring board according to the present invention for each of main steps;

5 (p) to 5 (t) are cross-sectional views showing the manufacturing steps following the steps of the manufacturing method shown in FIG. 4 for each step.

FIG. 6 is a sectional view showing a second configuration of the multilayer wiring board according to the present invention;

FIG. 7 is a sectional view showing a third configuration of the multilayer wiring board according to the present invention;

8 (a) to 8 (i) are cross-sectional views showing the configuration of a conventional printed wiring board at a manufacturing stage for each of main manufacturing steps.

FIG. 9 is a cross-sectional view showing a configuration of a conventional printed wiring board.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Electrically insulating base material 102 Through hole 103 Conductive paste (conductor) 104 Land (conductor wiring) 105 Through hole

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/40 H05K 3/40 K (72) Inventor Daizo Ando 1006 Kazuma Kadoma, Kadoma, Osaka Matsushita Electric Industrial F-term within the company (reference) 5E317 AA24 BB02 BB12 CC22 CC25 CD21 CD25 CD32 GG14 5E346 AA12 AA15 AA32 AA42 AA43 CC05 CC09 CC32 DD12 DD32 EE08 EE09 EE33 FF18 GG15 GG22 GG28 HH25

Claims (18)

[Claims] 1. An electric insulating base material provided with a conductor wiring on at least one of opposing surfaces is laminated, a through hole is provided between the opposing surfaces of the electric insulating base material, and a conductor filled in the through hole is provided. A multilayer wiring board for performing electrical connection between the layers of the conductor wiring, wherein at least one of the through holes penetrates over a plurality of layers of the laminated electrically insulating base material,
A multilayer wiring board, wherein electrical connection of the conductor wiring provided on both sides in the through direction of the through hole is performed by a conductor filled in the through hole. 2. The multilayer wiring board according to claim 1, wherein the through-hole penetrating the plurality of layers of the electrically insulating base material is formed so as to avoid an inner layer land. 3. The multi-layer structure according to claim 2, wherein the through-hole penetrating through the plurality of layers of the electrically insulating base material penetrates through the plurality of electrically insulating base materials including the surface electrically insulating base material. 3. The multilayer wiring board according to 1 or 2. 4. The device according to claim 1, wherein the through-hole penetrating a plurality of layers of the electrically insulating substrate is formed in a tapered shape. Multilayer wiring board. 5. An inner diameter of the through hole penetrating a plurality of layers of the electrically insulating base material, the inner diameter of the through hole increasing as the number of layers of the electrically insulating base material penetrating therethrough increases. 5. The multilayer wiring board according to any one of items 4 to 4. 6. The multilayer wiring board according to claim 1, wherein the electrically insulating base is made of a material having shrinkage. 7. The multilayer wiring board according to claim 6, comprising at least one layer of said electrically insulating base material made of said material having shrinkage. 8. The multilayer wiring board according to claim 7, wherein the electrically insulating base material made of the material having the contraction property is provided on a surface layer. 9. The multilayer wiring board according to claim 1, wherein electric insulating substrates having different thicknesses are mixed in the laminating direction. 10. The multilayer wiring board according to claim 9, wherein the thickest electric insulating base material is provided on a surface layer. 11. The film substrate according to claim 1, wherein at least one of the electrically insulating substrates is a film substrate having an adhesive on at least one of both opposing surfaces thereof.
The multilayer wiring board according to any one of the above. 12. A conductor wiring electrically connected to the conductor filled in a through hole penetrating a plurality of layers of the electrically insulating base material, at least one side of the conductor wiring in a penetrating direction of the through hole. The multilayer wiring board according to any one of claims 1 to 11, wherein a conductor wiring is embedded in the electrically insulating base material. 13. A through-hole forming step of forming at least one through-hole penetrating a plurality of layers of an electrically insulating base material containing a thermosetting resin, and a conductor having conductive particles and thermosetting resin in the through-hole. And a heating and pressurizing step of heating and pressurizing and hardening the electrically insulating base material and the conductor, wherein the heating and pressurizing step is performed in a direction in which the plurality of layers penetrate through holes. And a conductor wiring provided on both sides of the multi-layer wiring board is electrically connected to the conductor. 14. The method according to claim 13, wherein in the through hole forming step, through holes having different numbers of electrically insulating base material layers penetrating therethrough are formed at the same time. 15. The multi-layer wiring board according to claim 13, wherein, in the through-hole forming step, through-hole processing is performed simultaneously from both opposing surfaces of the laminated electrically insulating base material. Method. 16. The through hole forming step according to claim 13, wherein the through hole is formed such that the conductor wiring is exposed at the bottom of the through hole so as to be exposed inside the through hole. 3. The method for manufacturing a multilayer wiring board according to item 1. 17. The electric insulating base material for forming a through-hole is an electric insulating base material having at least one uncompressed electric insulating base material laminated on at least one surface layer. Item 17. The method for manufacturing a multilayer wiring board according to any one of Items 13 to 16. 18. The multilayer wiring according to claim 13, wherein, in the conductor filling step, the conductor is simultaneously filled from both opposing surfaces of the electrically insulating base material. Substrate manufacturing method.