JP2002198650A - Multi-layer wiring board and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer wiring board wherein electric characteristics of a through hole conductor extended through the main body of the board can be improved, and also to provide a method of manufacturing the same. SOLUTION: Conductor layers 12 and 13 are formed on a front and a rear face 4 and 5 of the main body 2 of the board having the front face 4 and the rear face 5. On these conductor layers 12 and 13, buildup layers BU1 and BU2, each of which comprises a resin insulation layer 10 and 11 and a conductor layer 18 and 24, are formed. In the main body 2 of the board, through holes 6 extended through the main body 2 of the board between the front face 4 and the rear face 5 are formed, and through hole conductors 8 are formed along the inner surfaces of the through holes 6. The inside of the through hole conductors 8 is filled with a resin filler 9. The thickness of the main body 2 of the board is less than 500 μm.

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 having a through-hole conductor penetrating a board body and having a build-up layer on the front and back surfaces of the board body and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with an increase in signal frequency, the loop inductance of a through-hole conductor penetrating a substrate body located at the center in the thickness direction of a multilayer wiring board is reduced to, for example, less than 0.4 pH. Is required. Such a loop inductance increases according to the length of the through-hole conductor, that is, the thickness of the substrate body. In general, the thickness of the board body in a conventional multilayer wiring board is
A through hole having a diameter of about 300 μm is formed between the front and back surfaces of the substrate body, and a cylindrical through-hole conductor having a required thickness is formed inside the through hole. Such through-hole conductors interconnect conductor layers formed on the top and bottom surfaces of the substrate body. A build-up layer in which an insulating layer and a conductor layer separate from the above are laminated is formed above / below the conductor layers on the front and back surfaces.

[0003]

However, it is difficult to reduce the loop inductance of the through-hole conductor provided through the conventional wiring board having a thickness of less than 0.4 pH. In order to solve this problem, there has been proposed a multilayer wiring board in which a pair of through-hole conductors having different diameters are concentrically arranged in a board body and penetrated in an inner / outer double structure (Japanese Patent Laid-Open No. 2000-216513). reference). However, the multilayer wiring board in which the through-hole conductor having the double structure is formed on the board body has a problem that the yield is low, and the number of manufacturing steps and cost are increased.
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problems in the conventional technology and to provide a multilayer wiring board capable of improving the electrical characteristics of a through-hole conductor penetrating a board body, and a method of manufacturing the same.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention maintains the strength of a substrate main body and the good electrical characteristics of a through-hole conductor penetrating the substrate main body while maintaining the thickness of the substrate main body. Is made as thin as possible. That is, in the multilayer wiring board of the present invention, a conductive layer is formed on each of the front and back surfaces of a substrate body having a front surface and a back surface, and a build-up including at least one of a resin insulating layer and a conductive layer on these conductive layers is provided. A layer is formed, a through hole penetrating between the front surface and the back surface of the substrate body and a through hole conductor along the inner wall of the through hole are formed, and the inside of the through hole conductor is filled with a filling resin. Wherein the thickness of the substrate body is less than 500 μm (not including 0).

The thickness of the substrate body is desirably 200 μm or more and less than 500 μm, and more desirably 350 μm or more and 450 μm or less. According to these, electrical conduction is provided between upper and lower conductor layers on the front and back surfaces of the substrate body, or between conductor layers in the upper and lower buildup layers via the through-hole conductor penetrating the substrate body. In this case, the electrical characteristics, for example, the loop inductance conductance, can be set to a favorable state at a low level of less than 0.4 pH. Therefore, it is possible to sufficiently cope with an increase in the signal frequency in the multilayer wiring board.

The substrate body is an insulating substrate which is located at the center in the thickness direction of the multilayer wiring board and serves as a skeleton of the multilayer wiring board, and is made of, for example, glass fiber or glass cloth and epoxy resin. It is formed into a sheet from a glass-resin composite material. Further, when the thickness of the substrate main body is 500 μm or more, the above-mentioned electrical characteristics of the through-hole conductor penetrating the substrate main body are deteriorated. However, when the thickness of the substrate main body is less than 200 μm, the amount of deflection of the substrate main body is apt to be excessive, and handling properties such as damage during handling are reduced. For this reason, the thickness of the substrate main body is desirably 200 μm or more and less than 500 μm, more desirably 350 μm or more and 450 μm.
m or less, more preferably 350 μm or more and 400 μm
m or less.

The diameter of the through hole is 50 μm.
The present invention also includes a multilayer wiring board having a thickness of at least m and less than 150 μm. According to this, a small-diameter through-hole conductor can be arranged along the inner wall of the through-hole. Therefore, a plurality of through-hole conductors can be arranged at a high density in the substrate body having the above thickness. If the diameter of the through-hole is less than 50 μm, the hole filling property for filling the resin inside the through-hole conductor formed along the hole is reduced. On the other hand, if the diameter is 150 μm or more,
It becomes difficult to arrange through-hole conductors at high density on the substrate body. In order to prevent these, the diameter of the through hole is set in the above range. A more desirable diameter of the through hole is in the range of 50 μm or more and 100 μm or less.

Further, a plurality of the through holes are formed in the substrate body, and a distance between centers between adjacent through holes is not less than 150 μm and not more than 300 μm, and a distance between inner walls of adjacent through holes is not less than 50 μm. Certain multilayer wiring boards are also included in the present invention. According to this, a plurality of through-hole conductors penetrating the substrate body,
The arrangement at a high density can be performed more reliably. In this specification, the center-to-center distance between through holes is
That is, it refers to the distance between the nearest through holes, and the distance between the inner walls of the through holes refers to the distance between adjacent inner walls between the through holes.

The center-to-center distance between the through holes is 150
If it is less than μm, the distance between adjacent through-hole conductors becomes too small and the insulation between them decreases. Meanwhile, 3
If it exceeds 00 μm, it becomes impossible to arrange through-hole conductors on the substrate body at high density. In order to prevent these, the center-to-center distance between the through holes is set in the above range. A more desirable range is 200 to 300 μm. This makes it easy to route signal wiring from, for example, an IC chip mounted on the main surface of the build-up layer on the surface of the substrate body to the conductor layer of the build-up layer below the back surface of the substrate body. Also, the distance between the inner walls of the through holes is 50μ.
If it is less than m, short-circuit failure may occur between the through-hole conductors formed along these inner walls.
In order to prevent this, the distance between the inner walls is set to 50 μm or more.

[0010] In addition, according to the present invention, there is provided a multilayer wiring board having a plurality of pads formed on the surface of the multilayer wiring board for connecting to electronic components, and having a diameter of 100 μm or less (not including 0). It can also be a substrate. Also,
The center-to-center distance between adjacent pads is 150 μm or less (0
Is not included).
In these cases, it is possible to reliably connect electronic components such as an IC chip mounted on the main surface of the multilayer wiring board and the internal conductor layer at a high density. When the diameter of the pad exceeds 100 μm, the center-to-center distance of 150 μm
This range is excluded because the following cannot be maintained and adjacent pads may be short-circuited. As used herein, the center-to-center distance between pads refers to the distance between adjacent, ie, closest, pads.

[0011] In addition, the through hole includes a multilayer wiring substrate in which a hole is formed in the substrate body by a laser and a fusion fixing layer is formed on an inner wall thereof. According to this, the through-hole having a diameter as small as less than 150 μm can be reliably drilled in the substrate main body, and the inner wall of the through-hole is in a state in which the material of the substrate main body is once melted by the laser and then solidified, that is, It becomes a fusion fixing layer (conductor penetration preventing layer). For this reason, it is possible to prevent the material of the through-hole conductor formed along the inner wall of the through hole from penetrating into the substrate from the inner wall. Therefore, a short circuit between adjacent through-hole conductors at high density can be suppressed. In addition, the through-hole may be a multi-layer wiring board in which a hole is formed by laser for the core substrate and an inner wall thereof is solidified after melting.

In addition, in any of the above multilayer wiring boards, the resin insulating layer may contain glass fiber, glass cloth, or glass filler. In this case, even if the substrate body is thin as described above, it is possible to easily prevent the entire multilayer wiring board from warping or bending. Further, any one of the multilayer wiring boards has a surface
A reinforcing plate may be provided on the (first main surface) or the back surface (second main surface). In this case, it is possible to increase the strength of the entire multilayer wiring substrate even with the thin substrate body as described above.

On the other hand, in the method of manufacturing a multilayer wiring board according to the present invention, the substrate body having a thickness of less than 500 μm (not including 0) is irradiated with a laser so that the front and back surfaces of the substrate body can be separated. Forming a through-hole having a diameter of 50 μm or more and less than 150 μm, and plating the inner wall of the through-hole and the front and back surfaces of the substrate body to form a through-hole conductor in the through-hole. Forming and forming a conductor layer on each of the front and back surfaces of the substrate body; printing and filling a resin paste inside the through-hole conductor to form a filled resin; Forming a build-up layer including at least one of a resin insulating layer and a conductive layer on each conductive layer.

According to this, it is possible to form a through-hole conductor penetrating the substrate body with a small diameter, and it is possible to reliably provide a multilayer wiring board in which the electrical characteristics of the through-hole conductor are improved. Further, since the diameter of the through hole is set to 50 μm or more, the filling of the filling resin into the inside of the through hole conductor formed along the through hole can be easily performed. Furthermore, in order to form through holes by laser,
The material of the through-hole conductor hardly permeates into the substrate body from the inner wall of the through-hole, and short-circuiting between adjacent through-hole conductors can be easily suppressed. Moreover, since the thickness of the substrate main body is less than 500 μm, the difference in diameter due to the taper along the axial direction of the through hole formed by the laser can be reduced. Therefore, it is possible to reliably provide a multilayer wiring board in which through-hole conductors having excellent electric characteristics are arranged at a high density, and which can sufficiently cope with an increase in signal frequency. The thickness of the substrate body is preferably 200 μm or more and less than 500 μm, more preferably 350 μm or more and 450 μm from the viewpoint of preventing bending.
μm or less, more preferably 350 μm or more and 400 μm or less.
μm or less.

In the step of forming a through hole in the substrate body, a plurality of through holes are formed, and a distance between centers between adjacent through holes is 150 μm.
m and 300 μm or less, and a method for manufacturing a multilayer wiring board in which the distance between inner walls of adjacent through holes is 50 μm or more. According to this, it is possible to reliably provide a multilayer wiring board in which the through-hole conductors are arranged at high density in the board body.

[0016]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a sectional view showing a main part of a multilayer wiring board 1 according to the present invention. As shown in FIG. 1A, a multilayer wiring board 1 includes a board body (core board) 2.
And copper conductor layers 12, 18, 24 formed on the surface 4 of the substrate body 2 and an epoxy-based resin insulation layer 10,
16, conductor layers 13, 19, 25 and resin insulating layers 11, 17, 23 formed below the back surface 5 of the substrate body 2. The substrate body 2 has a substantially square shape in plan view, a thickness T of less than 500 μm, for example, 400 μm, and a wire diameter of 5 to 5.
It is a 15 μm, for example, 7 μm, sheet-shaped insulating material made of a glass cloth or an epoxy resin containing glass fiber. The conductor layers 18, 24 above the front surface 4 of the substrate body 2 and the insulating layers 10, 16, 22 constitute a build-up layer BU1, and the conductor layers 19, 25 below the back surface 5 and the insulating layers 11, 1
7, 23 constitute the buildup layer BU2. The thickness of the conductor layer 18 and the like is about 15 μm,
Is about 30 μm.

As shown in FIG. 1A, the substrate body 2
A plurality of through holes 6 penetrating between the front surface 4 and the back surface 5 are formed, and a melt-fixed layer solidified after being once melted by a laser is present on the inner wall thereof. As shown in FIG. 1B, the through hole 6 is formed along the inner wall thereof.
The through-hole conductors 8 each having a circular cross section and filled with a filling resin 9 on the inside are formed in a cylindrical shape as a whole. The diameter D of the through hole 6 is 50 μm or more and less than 150 μm, for example, 95 μm.
The distance L between the centers 6 is 150 μm or more and 300 μm.
m or less, for example, 200 μm. The distance S between the inner walls of the adjacent through holes 6 is set to at least 50 μm. Further, the through-hole conductor 8 formed along the inner wall of the through-hole 6 is made of copper having a thickness of about 10 to several tens of μm, and the upper and lower ends of the upper and lower surfaces of the front and rear surfaces 4 and 5 of the substrate body 2. Are connected to the conductor layers 12 and 13 located in the first position.

As shown in FIG. 1A, the resin insulating layers 10 and 16 of the build-up layer BU1 have conductor layers 12 and
Via conductors (filled vias) connecting between 18 and 24,
20 are formed. The uppermost insulating layer (solder resist) 22 penetrates the conductive layer 24 (pad)
A plurality of upper solder bumps 28 made of, for example, Sn-Pb are formed to protrude higher than the first main surface 26, that is, the surface of the multilayer wiring board 1. Each bump 28
The terminals are individually connected to terminals of electronic components such as an IC chip (not shown) mounted on the first main surface 26. In the uppermost conductive layer 24 of the build-up layer BU1, a portion exposed on the first main surface 26 side is referred to as a pad, and when the solder resist layer 22 is provided thereon,
The portion exposed from the opening provided in the above is called a pad. The diameter of such a pad is 100 μm or less, for example, 85 μm, and the center-to-center distance between adjacent pads is 150 μm.
Hereinafter, for example, it is set to 100 μm.

Further, as shown in FIG. 1A, via conductors (filled vias) 15 and 21 for connecting between the conductor layers 13, 19 and 25 are formed on the build-up layer BU2.
17, the lowermost insulating layer (solder resist) 2
3, a recess 27 is formed which opens toward the second main surface 23a. The wiring 29 which extends from the conductor layer 25 into the recess 27 and is exposed is coated with Ni and Au plating, and is used for connection to a motherboard (not shown) on which the multilayer wiring board 1 itself is mounted. As described above, the multilayer wiring board 1 uses the thin substrate body 2 and has a plurality of through holes 6 penetrating therethrough and the through hole conductors 8 located inside the through holes 6 having a small diameter. For this reason, when conducting between the conductor layers 12 and 13 above / below the front and back surfaces 4 and 5 of the substrate body 2 via the through-hole conductors 8, for example, the loop inductance of the through-hole conductors 8 is less than 0.4 pH. It is easy to lower the level. Further, the plurality of through-hole conductors 8 can be arranged on the substrate body 2 at high density while preventing short circuit between them.

Therefore, according to the multilayer wiring board 1, not only between the conductor layers 12 and 13 but also between the conductor layers 18, 24, 19 and 25 of the build-up layers BU1 and BU2 including them can be stabilized. And I above the first main surface 26
The signal wiring between the C chip and the conductor layers 19 and 25 of the build-up BU2 on the second main surface (mother board) 23a side can be easily routed. For example, from the bump 28 used for signal transmission from the first main surface 26, the lead 28 is led to the second main surface 23a via the through-hole conductor 8, and the second
On the main surface 23a side, it is possible to easily route the signal wiring from the central portion of the multilayer wiring board 1 in plan view to the peripheral portion in plan view (so-called fan-out).

FIGS. 2 to 3 relate to main steps in the method of manufacturing the multilayer wiring board 1. 2 and 3, the thickness of the substrate main body 2 and the like is smaller than that in FIG.
As shown in FIG. 2A, the front and back surfaces 4 and 5 have a thickness of 16 μm.
Copper foils 3a and 3b are attached, and the thickness T is 500 μm.
A substrate body 2 made of less than glass-epoxy resin is prepared. As shown, a predetermined position on the surface 4 of the substrate body 2 is irradiated with carbon dioxide lasers (lasers) Ls, Ls almost vertically. As a result, as shown in FIG.
A plurality of through-holes 6 having a diameter D of 50 μm or more and less than 150 μm penetrating between the front and rear surfaces 4 and 5 are formed at predetermined positions in the substrate body 2. The inner wall of each through hole 6 is in a state of being solidified after being once melted by the laser Ls, and a denser structure, that is, a fusion-fixed layer is formed as compared with the initial matrix portion of the substrate body 2. The center distance L between the adjacent through holes 6 and 6 is 15
It is set within the range of 0 to 300 μm. The distance S between the inner walls of the adjacent through holes 6 is set to 50 μm or more. Further, each through hole 6 has a tapered shape whose diameter is reduced from the front surface 4 side to the rear surface 5 side. However, since the substrate body 2 is thin, the influence of the taper can be reduced.

Next, after a plating catalyst such as Pd is attached in advance to the through holes 6 and 6 and electroless copper plating is performed, electrolytic copper plating including the copper foils 3a and 3b of the substrate body 2 is performed. . As a result, as shown in FIG. 2C, the front and back surfaces 4, 5 of the substrate main body 2 are cylindrical in the through holes 6, 6.
Through-hole conductors 8, 8 extending therebetween are formed. Next, a resin paste made of an epoxy resin containing an inorganic filler is printed and filled in each hollow portion inside the through-hole conductors 8 and 8 using a squeegee and a metal mask (not shown), as shown in FIG. The filling resin 9 is filled and filled. Further, after an etching resist (not shown) having a predetermined pattern is formed at a predetermined position on the copper plating layer including the copper foils 3a and 3b on the front and back surfaces 3 and 4, the etching is performed with an etching solution (sodium sulfite, concentrated sulfuric acid, etc.). Apply.

When the resist is peeled off after the etching, as shown in FIG. 3B, the conductor layer 12 having a predetermined pattern following the resist is formed on the upper and lower surfaces 4 and 5 of the substrate body 2. , 13 are formed. At the same time, conductor layer 1
Since the conductors 2 and 13 are connected to the upper and lower ends of the through-hole conductors 8 and 8, they can be electrically connected to each other through the conductors. Next, as shown in FIG. 3C, resin films 10 and 11 are formed by applying an epoxy resin film on and under the conductor layers 12 and 13 by thermocompression bonding. Resin insulation layers 10, 1
Via holes 10a and 11a are formed at predetermined positions in 1 through which the conductor layers 12 and 13 are exposed on the bottom surface by photolithography or the like, and the via conductors 14 and 15 are filled and formed in these holes.

Thereafter, the conductor layers 18, 24, 19, 2
5. Build-up layers BU1, BU2 composed of resin insulation layers 16, 22, 17, 23 and via conductors 20, 21
Is formed by a known build-up process (semi-additive method, full-additive method, subtractive method, formation of a resin insulating layer by laminating a film-like resin material, photolithography technology, perforation of a via hole by laser processing, etc.). Thereby, the above-mentioned FIGS. 1 (A) and 1 (B)
Can be obtained.

According to the method for manufacturing the multilayer wiring board 1 as described above, since the laser Ls is used for the thin substrate body 2, the through hole 6 having a small diameter and an inner wall serving as a fusion fixing layer is used.
Can be obtained. Accordingly, the small-diameter through-hole conductors 8 can be formed at a high density without short-circuiting each other. Therefore, it is possible to reliably provide the multilayer wiring board 1 having excellent electrical characteristics such as a low level loop inductance of the through-hole conductor 8 and capable of increasing the internal signal frequency. The filling of the filling resin 9 is performed by filling the hollow portions inside the through-hole conductors 8 with the epoxy resin simultaneously with the thermocompression bonding of the epoxy resin film when the resin insulating layers 10 and 11 are formed. You may. According to this manufacturing method,
The present invention can be applied to a case where the substrate body 2 is thin, and does not require a separate hole filling step.

[0026]

Here, specific examples of the multilayer wiring board 1 of the present invention will be described together with comparative examples. Thickness T is 100μ
m, 150μm, 200μm, 300μm, 350μ
Through holes 6 each having a diameter D of 95 μm were drilled in the substrate main body 2 of m, 400 μm, and 450 μm with a laser Ls to form through-hole conductors 8 having a thickness of 16 μm along the inner wall and filled with a filling resin 9. Seven types of wiring boards 1 were prepared in which conductor layers 12 and 13 having a thickness of 16 μm were formed on the front and back surfaces 4 and 5 of each substrate body 2. On the other hand, when the thickness T is 500 μm, 600 μm, 700 μm, 800
The diameter D is 95 μm on the substrate body 2 of μm and 900 μm.
Five types of wiring boards of comparative examples were prepared in which the through-holes 6 of m were drilled with laser Ls, and the same through-hole conductors 8, filling resin 9, and conductor layers 12 and 13 were formed.

The loop inductances of the through-hole conductors 8 of the twelve types of multilayer wiring boards (1) were measured under the same conditions. The results are shown in the graph of FIG. FIG.
According to the graph of (A), the thickness T of the substrate body 2 is 500 to
In all of the five types of comparative examples of 900 μm, the loop inductance was as high as 0.4 pH or more. In contrast, the thickness T of the substrate body 2 is 100 μm, 150 μm.
m, 200 μm, 300 μm, 350 μm, 400 μ
In all of the wiring boards 1 of the seven examples of m and 450 μm, the loop inductance was a low level of less than 0.4 pH.

As shown in the graph of FIG. 4A, the loop inductance of the through-hole conductor 8 and the thickness T of the substrate body 2 are substantially proportional to each other. As the length of the wire 8 becomes shorter, the loop inductance tends to be reduced. As a result, each wiring board 1 of the embodiment has a good electric region characteristic. However, in the wiring board 1 of the embodiment in which the thickness T is 100 μm and 150 μm, the board main body 2 is particularly thin, so that it is easily bent.
For this reason, handling properties in the manufacturing process and the like are reduced, and the yield may be reduced due to the bending of the substrate body 2, for example, because the substrate body 2 is easily damaged. On the other hand, when the thickness T is 200 μm or more, specifically 350 μm or more,
It is even more effective in preventing the substrate body 2 from being bent,
When the value is not more than m, the loop inductance can be further reduced from 0.4 pH, which is preferable.

Further, a multilayer wiring board 70 of a comparative example as shown in FIGS. 4B and 4B was separately prepared. This wiring board 7
0 indicates that the substrate T has a thickness T of 800 μm.
An outer through hole 76 having a diameter of 300 μm penetrating between the back surfaces 74 and 75 and an outer through hole conductor 77 having a thickness of 16 μm are provided inside the outer through hole 76. The conductor 77 has conductor layers 82 and 83 on the front and back surfaces 74 and 75 of the substrate body 72 at the upper and lower ends.
Is connected to As shown in FIG. 4B, an inner through hole 79 having a diameter D of 95 μm and an inner through hole having a thickness of 16 μm along the inner wall are provided at the center of the filling resin 78 filled inside the through hole conductor 77. A conductor 80 penetrates concentrically with the outer through-hole conductor 77, and the inside thereof is filled with a filling resin 81. As shown in FIG. 4B, the inner through-hole conductor 80 is connected at upper and lower ends to conductor layers 86 and 87 in the upper and lower buildup layers. Note that the buildup layers above and below the substrate body 72 are sandwiched by the resin insulation layers 84, 88, 85,
89.

In the multilayer wiring board 70 of the comparative example as described above, the loops in the inner through-hole conductors 80 are applied to the inner and outer through-hole conductors 80 and 77 under the same conditions as described above. The inductance was measured. The results are shown as B in the graph of FIG. According to this, the loop inductance is lower than that of the wiring board of the comparative example in which the same thickness T as the board body 72 is 800 μm. This is because the mutual inductance (2 × M) between the inner and outer through-hole conductors 80 and 77 becomes large, so that the total loop inductance obtained by subtracting the mutual inductance from the total value of the self-inductances of the two is reduced. It is due to.

However, also in the multilayer wiring board 70, since the thickness T of the board main body 72 is 800 μm, the loop inductance is 0.1 μm as shown in the graph of FIG.
It was 4 pH. It is theoretically possible to make the loop inductance less than 0.4 pH by further reducing the thickness T of the substrate main body 72. In this case, however, the thin-walled substrate main body 72 has a double-structured inner / outer through-hole. Conductor 8
Forming 0,77 with high accuracy is not practical because it requires many man-hours and lowers the yield. From the above results, the superiority of the multilayer wiring board 1 of the present invention, in which the thickness T of the board main body 2 is within the range of the arrow X shown in the graph of FIG.

FIG. 5 shows a main part of a multilayer wiring board 30 according to another embodiment of the present invention. As shown in FIG. 5, the multilayer wiring board 30 includes a board body (core board) 32 and copper conductor layers 42, 46 formed on a surface 34 of the board body 32.
54 and epoxy resin insulating layers 40, 44, 50 including glass filler, conductor layers 43, 47, 53 formed under the back surface 35 of the substrate main body 32 and resin insulating layers 41, 45, 51 including glass filler. Having. Substrate body 32
Is an insulating material made of a glass cloth or a glass fiber-containing epoxy resin having a substantially square shape in plan view and a thickness T of less than 500 μm. Further, the conductor layers 46 and 54 and the resin insulation layers 40, 44 and 50 on the surface 34 of the substrate main body 32 are provided.
Constitutes the build-up layer BU3, and the wiring layers 47, 53 and the resin insulating layers 41, 45, 51 below the back surface 5 constitute the build-up layer BU4.

As shown in FIG. 5, a plurality of through holes 36 are formed in the substrate body 32 and the resin insulating layers 40 and 41, and the through holes 36 are formed in the through holes 36 as shown in FIG. Through-hole conductors 38 each having a circular shape and filled with a filling resin 39 are individually formed. The diameter D of each through hole 36 is 50 μm.
m and less than 150 μm, the distance L between the centers of the adjacent through holes 36 is set to be 150 μm or more and 300 μm or less, and the distance S between the inner walls of the adjacent through holes 36 is 36 μm. That is all. The through-hole conductor 38 has a thickness of about 10
Conductor layers 42, 43 located on the front and back surfaces 34, 35 of the substrate body 32 in the middle of the upper and lower portions thereof.
And the build-up layer BU at the upper and lower ends.
3 and BU4 are connected to the conductor layers 46 and 47.
The conductor layers 42 and 43 are power supply or ground patterns which are almost solidly attached to the front and back surfaces 34 and 35.

Further, as shown in FIG. 5, a via conductor 48 connecting the conductor layers 46 and 54 is formed in the resin insulating layer 44 of the build-up layer BU3. The uppermost insulating layer (solder resist) 50 has solder bumps 58 made of, for example, Sn-Pb positioned in holes 56 penetrating therethrough and communicating with via conductors (pads) 48 on the first main surface 5.
It protrudes higher than 2. Each bump 58 is individually connected to a terminal of an IC chip (not shown) mounted above the first main surface 52. In addition, as shown in FIG.
A copper reinforcing plate 60 having an opening formed therein to avoid each of the bumps 58 is mounted on the upper surface 2 with an adhesive (epoxy type, thermosetting). The surface of the reinforcing plate 60 is coated with Ni and Au plating.

As shown in FIG. 5, a via conductor 49 connecting the conductor layers 47 and 53 is formed in the resin insulating layer 45 of the build-up layer BU4, and the resin insulating layer (solder The (resist) 51 is formed with concave portions 57 and 59 that are open toward the second main surface 51a. Recess 57
Ni and A are provided on the surfaces of the via conductor 49 exposed in the inside and the via conductor 49 and the conductor layer 53 exposed in the recess 59.
u plating is respectively coated. As shown in FIG. 5, a chip capacitor 61 having an electrode 62 is mounted on a via conductor 49 in a concave portion 59 opened on the second main surface 51a side via a solder 63 made of Sn-Sb. A pin 65 made of Kovar is connected to the via conductor 49 in the concave portion 57 via the solder 63. In addition, the concave portion 5
The conductor layer 53 in 9 can also be used for solder connection with a motherboard (not shown) on which the multilayer wiring board 30 is mounted.

As described above, the multilayer wiring board 30 uses the thin board main body 32, and has a plurality of through holes 36 penetrating therethrough and the through hole conductors 38 located along the inner walls thereof having a small diameter. . Therefore, the substrate body 32
When conducting between the conductor layers 42, 43, 46, 47, 53, and 54 via the through-hole conductor 38, for example, the loop inductance of the through-hole conductor 38 can be easily reduced to less than 0.4 pH. . Further, a plurality of through-hole conductors 38 can be arranged on the substrate main body 32 at high density while preventing short circuit between them. Therefore, according to the multilayer wiring board 30, the conductor layers 42, 43, 4
Build-up layer B containing these as well as 6,47
Electrical conduction between the conductor layers 54 and 53 of U3 and BU4 can be stabilized. Moreover, signal wiring between the IC chip on the first main surface 52 and the conductor layer 43 on the rear surface 35 and between the conductor layers 47 and 53 of the build-up BU 4 can be easily routed.

The present invention is not limited to the embodiments and examples described above. The substrate body 2, 3
Material 2 is a glass woven fabric having the same heat resistance, mechanical strength, flexibility, workability, and the like, as well as the glass-epoxy resin composite material, bismaleimide / triazine (BT) resin, and epoxy resin. Alternatively, a glass fiber-resin composite material that is a composite material of glass fiber such as a glass woven fabric and a resin such as an epoxy resin, a polyimide resin, or a BT resin may be used. Alternatively, a composite material of an organic fiber such as a polyimide fiber and a resin, or a PTF having continuous pores
It is also possible to use a resin-resin composite material in which a resin such as an epoxy resin is impregnated into a fluorine resin having a three-dimensional network structure such as E. Further, the material of the through-hole conductors 8, 38, the conductor layers 12, 13 and the like may be Ag, Ni, Ni-Au, or the like in addition to Cu, or may be a conductive material without using a plating layer of these metals. It may be formed by a method such as applying a conductive resin.

The material of the resin insulating layers 10 and 11 is not only a material mainly composed of the epoxy resin, but also a polyimide resin having the same heat resistance and pattern moldability.
BT resin, PPE resin, or P with continuous pores
A resin-resin composite material in which a resin such as an epoxy resin is impregnated into a fluorine-based resin having a three-dimensional network structure such as TFE can also be used. The resin insulating layer can be formed by a method of applying a liquid resin by a roll coater, in addition to a method of thermocompression bonding an insulating resin film. Further, the composition of the glass cloth or glass filler mixed into the resin insulating layer is E glass, D glass, Q glass,
Any of S glasses or a combination of two or more of them may be used. Further, the arrangement of the through-holes 6 and the through-hole conductors 8 on the substrate main bodies 2 and 32 may be lattice, staggered, rectangular, or rectangular frame in plan view on the assumption that the center-to-center distance L is maintained. Any arrangement pattern such as a shape can be used. In addition, laser L
s is not limited to the carbon dioxide laser, but a YAG laser,
An excimer laser, a semiconductor laser, or the like can also be used. Further, the reinforcing plate 60 may be made of a metal such as stainless steel, Fe-42 wt% Ni alloy (so-called 42 alloy), Kovar (Fe-29 wt% Ni-17 Cowt% alloy), aluminum alloy, titanium alloy, etc., in addition to copper. Alloys can also be applied.

[0039]

According to the multilayer wiring board of the present invention described above, the through-hole conductor penetrating through the board main body between the conductive layers on the front and back surfaces of the board main body or the conductive layers in the upper and lower build-up layers. The electrical characteristics when conducting through the loop, for example, the loop inductance
It can be in a good condition at a low level below the pH.
Therefore, a multilayer wiring board that can sufficiently cope with an increase in the signal frequency can be obtained. Further, according to the multilayer wiring board of the second aspect, since the through-hole conductor having a small diameter can be arranged along the inside of the through-hole, the plurality of through-hole conductors penetrating through the substrate body having the above thickness can be formed at a high density. Can be arranged. Furthermore, according to the multilayer wiring board of the third aspect, the plurality of through-hole conductors can be more securely arranged on the board body at high density.

On the other hand, according to the method for manufacturing a multilayer wiring board of the present invention, it is possible to form a multilayer wiring board in which a through-hole conductor penetrating the substrate body can be formed to have a small diameter and the electrical characteristics of the through-hole conductor are improved. Can be provided reliably.
In addition, since the diameter of the through hole is 50 μm or more, the filling of the filling resin into the inside of the through hole conductor formed along the through hole can be easily performed. Further, since the through-hole is formed by the laser, the material of the through-hole conductor hardly penetrates into the substrate body from the inner wall of the through-hole, and the short circuit between the adjacent through-hole conductors can be easily suppressed. Further, since the thickness of the substrate main body is reduced to less than 500 μm, the difference in diameter due to the taper along the axial direction of the through hole formed by the laser can be reduced. Therefore, it is possible to reliably provide a multilayer wiring board in which through-hole conductors having excellent electric characteristics are arranged at a high density, and which can sufficiently cope with an increase in signal frequency.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing a main part of a multilayer wiring board according to the present invention, and FIG. 1B is a cross-sectional view taken along a line BB in FIG.

FIGS. 2A to 2C are schematic views showing main steps of a method for manufacturing the multilayer wiring board of FIG. 1;

3 (A) to 3 (C) are schematic views showing main steps in a manufacturing method following FIG. 2 (C).

FIG. 4A is a graph showing the relationship between the thickness of the substrate body and the inductance of the through-hole conductor in the example and the comparative example, FIG. 4B is a cross-sectional view showing the main part of the multilayer wiring board of the comparative example, (b) is a cross-sectional view taken along a line bb in (B).

FIG. 5 is a sectional view showing a main part of a multilayer wiring board according to another embodiment of the present invention.

[Explanation of symbols]

1,30 ……………………………………………
Multilayer Wiring Board 2, 32 ……………………………………………
Substrate body 4,34 ……………………………………………
Surface 5,35 ………………………………………………
Back 6,36 ……………………………………………
Through hole 8, 38 ……………………………………………
Through-hole conductor 9, 39 …………………………………………
Filled resin 10, 11, 16, 17, 22, 23, 40, 41, 44, 45, 50, 51 ...
Resin insulation layer 12, 13, 18, 19, 24, 25, 42, 43, 46, 47, 53, 54 ...
Conductor layers BU1 to BU4 .................................
Build-up layer T ………………………………………………………
Thickness of substrate body D ……………………………………………………
Diameter of through hole L …………………………………………………………………………………………………………………………………… ………… Distance between inner walls of through holes Ls …………………………………………………
laser

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/42 610 H05K 3/42 610C F term (Reference) 5E317 AA24 BB01 BB11 CC31 CD27 CD32 GG11 GG14 5E346 AA06 AA41 CC32 DD12 DD25 DD48 EE31 FF07 FF15 GG15 GG17 GG22 HH02 HH25

Claims (6)

[Claims] A conductor layer is formed on each of front and back surfaces of a substrate body having a front surface and a back surface, and a build-up layer including at least one of a resin insulating layer and a conductor layer is formed on these conductor layers. In addition, a through-hole penetrating between the front surface and the back surface of the substrate body and a through-hole conductor along the inner wall of the through-hole are formed, and the inside of the through-hole conductor is a multilayer wiring board filled with a filling resin. And a thickness of the substrate main body is less than 500 μm. 2. The multilayer wiring board according to claim 1, wherein the diameter of said through hole is not less than 50 μm and less than 150 μm. 3. A plurality of said through holes are formed in said substrate body, a distance between centers between adjacent through holes is 150 μm or more and 300 μm or less, and a distance between inner walls of adjacent through holes is 50 μm or more. The multilayer wiring board according to claim 1 or 2, wherein: 4. The method according to claim 1, wherein the through hole is formed by drilling a laser beam into the substrate body, and a fusion fixing layer is formed on an inner wall of the through hole. Multilayer wiring board. 5. A substrate body having a thickness of less than 500 μm is irradiated with a laser so as to penetrate between a front surface and a back surface of the substrate body and have a diameter of 50 μm or more and 1 μm or more.
Forming a through hole of less than 50 μm; plating the inner wall of the through hole and the front and back surfaces of the substrate body to form a through hole conductor in the through hole and forming a conductor layer on the front and back surfaces of the substrate body; Forming a filling resin by printing and filling a resin paste inside the through-hole conductor; and forming a resin insulating layer and a conductor on each conductor layer on the front and back surfaces of the substrate body. Forming a build-up layer including at least one of the layers. 6. A process for forming a through hole in the substrate body, wherein a plurality of through holes are formed,
The distance between centers between adjacent through holes is set to be 150 μm or more and 300 μm or less, and the distance between inner walls of adjacent through holes is set to 50 μm or more. Of manufacturing a multilayer wiring board.