JP4340832B2 - Wiring board and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wiring board and a manufacturing method thereof, and more particularly to a technique effective when applied to a wiring board in which conductor wirings formed on both surfaces of an insulating substrate are connected by through holes.
[0002]
[Prior art]
Conventionally, a wiring board used for mounting a semiconductor device or a semiconductor device (semiconductor package) such as a CSP (Chip Size Package) or BGA (Ball Grid Array) has a conductive wiring pattern (on the insulating substrate). Hereinafter, it is referred to as a conductor wiring).
[0003]
In recent years, the number of conductor wirings formed on the insulating substrate has increased due to high integration and high functionality of the semiconductor device to be mounted, and the wiring density of the conductor wiring has been reduced by downsizing the wiring substrate. In order to efficiently form the conductor wiring, for example, a double-sided wiring board in which conductor wiring is formed on both sides of the insulating substrate, and wiring on both sides of the insulating board and inside the insulating substrate are also provided. A multilayer wiring board in which layers are formed is used.
[0004]
An electronic device in which the semiconductor device is mounted on a double-sided wiring board in which conductor wiring is formed on both sides of the insulating board, for example, as shown in FIGS. 23 and 24, a plurality of semiconductor chips and semiconductors on the insulating board 1 Devices, electronic components C1, C2, C3, C4, and C5 such as resistance elements and capacitors are mounted, and the connection terminals of the electronic components mounted in the mounting regions are connected on the insulating substrate 1. Conductor wiring (connection terminals) for directly inputting / outputting signals or power supply voltages to / from the semiconductor chip or the semiconductor device is provided. At this time, for example, as shown in FIG. 25 and FIG. 26, the first main wiring 201 formed on the first main surface 1A of the insulating substrate 1 and the second main surface facing the first main surface 1A. By connecting the second conductor wiring 202 formed on 1B through the through-hole 203A, even when the number of conductor wirings is increased, the wiring length is short and an efficient wiring pattern can be obtained.
[0005]
The manufacturing method of the double-sided wiring board will be briefly described. First, for example, on the first main surface 1A and the second main surface 1B of the tape-like insulating substrate 1, for example, thin film conductors 2A, 2B such as copper foil Form. As the insulating substrate 1, for example, a polyimide tape or a glass epoxy substrate in which a glass cloth is impregnated with an insulating resin such as an epoxy resin is used. The thin film conductors 2A and 2B are formed by, for example, a method of bonding an electrolytic copper foil or a rolled copper foil or a method of thinly depositing copper on the insulating substrate 1 by sputtering or the like.
[0006]
Next, as shown in FIG. 27A, via holes 1C are formed at predetermined positions on the insulating substrate 1 on which the thin film conductors 2A and 2B are formed. The via hole 1C is formed by, for example, a punching process using a mold or a laser process that irradiates a carbon dioxide laser or an excimer laser.
[0007]
Next, for example, after a copper plating layer (pattern plating) 203 is formed on the thin film conductors 2A and 2B on the first main surface 1A side and the second main surface 1B side of the insulating substrate 1, FIG. ), The pattern plating 203 and the thin film conductors 2A and 2B are etched to form the first conductor wiring 201 and the second conductor wiring 202. At this time, the pattern plating 203 is also formed on the inner wall of the via hole 1C, and a portion formed in the via hole 1C becomes a through hole 203A.
[0008]
First, the copper plating layer (pattern plating) 203 is formed by thinning a thin film conductor such as a copper plating layer (not shown) on the inner wall of the via hole 1C and the surfaces of the thin film conductors 2A and 2B by using an electroless plating method. After the formation, for example, a copper plating layer 203 having a thickness of about 7 μm to 8 μm is formed by using an electroless plating method or an electroplating method.
[0009]
The step of forming a thin copper plating layer on the inner wall of the via hole using an electroless plating method is, for example, as a pre-process of plating treatment, for example, when the inner wall of the via hole 1C is punched by the mold. Electroless plating after the process of removing resin smear (dirt) such as resin stains caused by the breakage or burr of the mold or friction between the mold and the insulating substrate, or resin remaining during laser processing (desmear) In order to attach the catalyst (palladium metal) used in the method, a step of removing the film on the surface of each thin film conductor 2A, 2B is performed, and the via hole and the surface treatment of the thin film conductor are performed.
[0010]
Thereafter, colloidal particles of palladium metal such as Pd—Sn alloy, for example, are adsorbed on the inner wall of the via hole 1C and the surfaces of the thin film conductors 2A and 2B as the electroless plating catalyst. After removing and exposing an alloy nucleus that functions as a catalytically active species, the alloy core is immersed in a plating bath, and palladium (Pd) is used as a catalyst to form copper (Cu) on the inner wall of the via hole 1C and the surfaces of the thin film conductors 2A and 2B. To precipitate.
[0011]
Next, on the copper plating layer 203, for example, a plating layer 3 is formed by laminating gold (Au) plating with nickel (Ni) plating as a base. At this time, for example, a nickel plating layer having a thickness of about 3 μm and a gold plating layer having a thickness of about 0.1 μm are laminated on the surface of the pattern plating 203 and the through hole 203A.
[0012]
Further, at this time, the plating layer 3 prevents deterioration of electrical characteristics due to oxidation of the first conductor wiring 201 and the second conductor wiring 202, and connectivity with a semiconductor chip or a connection terminal of a semiconductor device to be mounted. For example, in addition to the plating layer 3 in which the nickel plating layer and the gold plating layer are laminated, for example, a plating layer such as tin (Sn) plating or tin-lead (Sn—Pb) alloy is used. It is done.
[0013]
In addition to the above procedure, for example, the plating layer 3 is formed before the thin film conductors 2A and 2B are etched, and the thin film conductors 2A and 2B are etched using the plating layer 3 as an etching mask. There is also. In this case, the lower part of the plating layer 3 is undercut during the etching process, resulting in an overhang. Therefore, fusing is performed after the etching process. As the plating layer 3 at this time, for example, a plating layer such as tin (Sn) plating or tin-lead (Sn—Pb) alloy is used.
[0014]
Thereafter, a solder resist 7 is formed on predetermined regions of the first conductor wiring 201 and the second conductor wiring 202 on the insulating substrate 1, and electronic components C1, C2, C3, C4 such as a semiconductor device, a resistance element, and a capacitor element are formed. , C5, an electronic device as shown in FIGS. 23 and 24 can be obtained. At this time, for example, as shown in FIG. 24, when the external terminal C3A of the semiconductor chip C3 and the first wiring conductor 201 are connected using the bump 6, sealing is performed between the semiconductor chip C3 and the wiring substrate. An insulator 8 is poured to seal the underfill.
[0015]
[Problems to be solved by the invention]
However, in the conventional technique, when a glass epoxy substrate is used as the insulating substrate 1, a fibrous glass yarn 101 is woven as shown in FIGS. 28 (a) and 28 (b). Since the glass cloth is impregnated with the epoxy resin 102, for example, when the via hole 1C is formed by punching with a mold, the glass yarn 101 is not cut cleanly, and FIG. As shown in FIG. 29 (b), when the tip 101A of the glass yarn protrudes and remains in the via hole 1C, or is broken inside the epoxy resin 102, a small cavity is formed on the inner wall of the via hole 1C. There are many cases.
[0016]
If the tip 101A of the glass yarn protrudes from the inner wall of the via hole 1C or a small cavity is formed in the inner wall of the via hole 1C, a thin copper plating layer is formed on the inner wall of the via hole 1C by using an electroless plating method. When the copper plating layer 203 is formed, as shown in FIG. 30, a hole (pinhole) is opened in the through-hole plating 203A by the protruding tip 101A of the glass thread, or the inner wall of the via hole 1C. Air remains in the cavity. If pin holes are formed or air remains in the cavity in this way, cracks may occur in the through-hole plating 203A or the plating layer 3A when the plating layer 3 is formed in a subsequent process or the like. There is a problem that the plating 203A is peeled off and the connection reliability of the through hole 203A is lowered.
[0017]
In addition, not only when the glass epoxy substrate is used, but also when the via hole 1C is formed by punching with a mold even when a single material substrate such as polyimide tape is used, the fracture occurs. Since the smear is generated on the inner wall of the via hole 1C due to the friction between the mold and the polyimide tape, the smear cannot be sufficiently removed during the surface treatment before the electroless plating. As a result, there is a problem that pinholes and cracks are generated in the electroless copper plating layer, and the connection reliability of the through hole 203A is lowered.
[0018]
Further, for example, after forming the via hole 1C in the insulating substrate 1 on which the thin film conductors 2A and 2B are formed, when forming the through hole plating 203A, the inner wall of the via hole 1C is formed using an electroless plating method. A process for forming a thin copper plating layer is required. The number of processes for surface treatment of the inner wall of the via hole 1C and the thin film conductors 2A and 2B and the process for applying a catalyst increase, and materials used in each process (chemicals) ) Increases, the manufacturing cost of the double-sided wiring board increases.
[0019]
An object of the present invention is to provide a technique capable of improving the connection reliability of the through hole in a wiring board in which conductor wiring is formed on both surfaces of an insulating substrate and the conductor wiring is connected by a through hole. It is in.
[0020]
Another object of the present invention is to provide a technique capable of simplifying the manufacturing process of the wiring board in the wiring board in which the conductor wiring is formed on both surfaces of the insulating substrate and the conductor wiring is connected by through holes. There is to do.
[0021]
The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.
[0022]
[Means for Solving the Problems]
The outline of the invention disclosed in the present invention will be described as follows.
[0023]
(1) In the wiring board in which the first conductor wiring is provided on the first main surface of the insulating substrate, and the second conductor wiring is provided on the second main surface opposite to the first main surface of the insulating substrate, The insulating substrate is a wiring substrate in which a predetermined position is depressed, and the first conductor wiring and the second conductor wiring are electrically connected in the depressed portion.
[0024]
According to the means (1), the insulating substrate in a portion where the first conductor wiring and the second conductor wiring are electrically connected, for example, a portion where a through hole is provided is depressed and thinned. Smear hardly occurs on the inner wall of the via hole opened to provide the through hole. Therefore, pin holes and cracks due to the smear are unlikely to occur in the through hole, and the connection reliability between the first conductor wiring and the second conductor wiring through the through hole can be prevented from decreasing.
[0025]
In the means (1), for example, when the thickness of the recessed portion of the insulating substrate is reduced, the first main surface and the second main surface of the insulating substrate are opened in contact with each other. In that case, the first conductor wiring and the second conductor wiring can be directly connected without using the through hole, and the connection reliability is improved as compared with the case through the through hole.
[0026]
In the means of (1), only the first main surface side of the insulating substrate may be depressed, or both the first main surface side and the second main surface side may be depressed. Good. When both sides of the first main surface side and the second main surface side of the insulating substrate are depressed, when viewed with an insulating substrate having the same thickness, compared to the case where only the first main surface side is depressed. The depth of the depressed portion can be reduced, and the area of the depressed portion can be reduced. Therefore, the area of the portion where the through hole is provided can be reduced, and the wiring board can be miniaturized or the wiring density can be increased. Further, stress (stress) due to deformation at the outer peripheral portion of the depressed portion of the first conductor wiring or the second conductor wiring is reduced, and disconnection due to cracks can be prevented.
[0027]
Further, since the thickness of the insulating substrate in the portion where the through hole is provided is thin, the degree of thermal expansion in the plate thickness direction of the insulating substrate is reduced. Therefore, the load applied to the through hole due to the thermal expansion of the insulating substrate is eliminated, and the through hole can be provided by the plating layer provided on the surface of the conductor wiring. Therefore, it is possible to reduce the hole diameter when opening the via hole necessary for providing the through hole, to reduce the area of the portion where the through hole is provided, and to reduce the size of the wiring board, or wiring The density can be increased. At this time, the plating layer provided on the surface of the conductor wiring is, for example, a laminate of a nickel (Ni) plating layer and a gold (Au) plating layer.
[0028]
Further, according to the means of (1), the portion of the insulating substrate provided with the through hole is depressed, and the thickness of the portion provided with the through hole is equal to that of the portion provided with the through hole. Since the thickness of the outer region is thinner, the through hole can be provided without providing a conductive thin plating layer on the inner wall of the via hole using an electroless plating method. It is possible to reduce the material (chemicals) to be produced and reduce the manufacturing cost of the wiring board.
[0029]
Further, as the insulating substrate, for example, when using a substrate in which a fibrous glass thread is provided inside an epoxy resin, such as a glass epoxy substrate, the via hole in which the through hole is provided The glass yarn can be prevented from protruding, and the through hole can be prevented from generating pinholes and cracks. Therefore, the connection reliability through the through hole can be improved.
[0030]
(2) forming a first thin film conductor on the first main surface of the insulating substrate, and forming a second thin film conductor on the second main surface of the insulating substrate opposite to the first main surface; A step of recessing a predetermined position of the insulating substrate on which the first thin film conductor and the second thin film conductor are formed, a step of opening the recessed region of the insulating substrate, and through-hole plating on the opening of the insulating substrate. A method of manufacturing a wiring board comprising: a step of forming; and forming a first conductor wiring by patterning the first thin film conductor, and forming a second conductor wiring by patterning the second thin film conductor. .
[0031]
According to the means of (2), when the insulating substrate is opened, the distance between the first thin film conductor and the second thin film conductor is reduced by recessing the opening region of the insulating substrate. . Therefore, in the step of forming the through-hole plating, the through-hole can be formed without forming a copper plating layer on the inner wall of the opening by using an electroless plating method as in the prior art. The manufacturing process of the substrate can be simplified, and the manufacturing cost can be reduced. At this time, the step of forming the through-hole plating and the step of forming the first conductor wiring and the second conductor wiring can be switched in order according to a manufacturing method. For example, the through-hole plating can be performed using an electroplating method. After forming the plating, the method of forming the first conductor wiring and the second conductor, or after forming the first conductor wiring and the second conductor wiring, the first conductor wiring and the second conductor wiring A method of forming the through-hole plating simultaneously with the plating layer formed on the surface is conceivable.
[0032]
Further, by sinking the insulating substrate, the degree of thermal expansion in the thickness direction of the insulating substrate around the via hole is reduced. Therefore, the load applied to the through hole due to the thermal expansion of the insulating substrate can be reduced, the conventional step of forming the electrolytic copper plating layer can be omitted, and the manufacturing cost of the wiring substrate can be reduced.
[0033]
When the through-hole plating is formed simultaneously with the plating layers formed on the surfaces of the first conductor wiring and the second conductor wiring, the through-hole plating is formed, for example, by stacking gold plating with nickel plating as a base. Is preferred.
[0034]
Further, by making the opening portion of the insulating substrate depressed and thinning, for example, when opening by punching with a mold or laser processing, it is difficult for smear to occur on the inner wall of the opening, and the through hole When the plating is formed, pinholes and cracks due to the smear do not occur. Therefore, connection reliability through the through-hole plating can be improved.
[0035]
In addition, for example, a method of sinking a predetermined position of the insulating substrate on which each thin film conductor is formed includes a method of pressing a columnar pressing jig from the first main surface side, the first main surface side, and the There is a method of pressing a pressing jig from each of the second main surface side. At this time, by pressing the pushing jig, the insulating substrate in a portion in contact with the pushing jig is pushed outward, so that the insulating board is depressed. Moreover, since the fluidity of the insulator (insulating substrate) is increased by heating the insulating substrate near the glass transition temperature Tg and softening, the insulator is pressed when the pushing jig is pressed. Can be pushed out and can be depressed with weak force.
[0036]
Further, the method of sinking the insulating substrate is not limited to the method of pressing the pushing jig in a state where the insulating substrate is heated and softened. For example, the insulating substrate is thermally cured at an intermediate stage of the curing reaction. A method is also conceivable in which a B resin is completely cured after a predetermined position is depressed by the pushing jig using a functional resin (B stage resin). In this case, since the B-stage resin has high fluidity at an intermediate stage of the curing reaction, it is not necessary to heat and can be easily depressed. For the B stage resin, for example, an epoxy resin is used.
[0037]
In addition, as the insulating substrate, for example, when using a substrate in which a fibrous glass thread is provided, such as a glass epoxy system, when the insulating substrate is depressed by pressing the mold, Since the glass yarn in the portion where the mold hits is pushed out of the depressed area along the spherical surface of the tip of the mold, when the inside of the depressed area is opened, the inside of the opening The glass yarn does not protrude. Therefore, it is possible to prevent a pin hole or a crack from being generated in the through hole due to the glass yarn (glass burr) protruding into the opening, and to improve the connection reliability through the through hole.
[0038]
(3) forming a first thin film conductor on one main surface of the insulating substrate; sinking a predetermined position of the insulating substrate on which the first thin film conductor is formed; and sinking a predetermined position of the insulating substrate. And forming a second thin film conductor on a main surface of the insulating substrate opposite to the main surface on which the first thin film conductor is formed, and patterning the first thin film conductor to form a first conductor wiring. And a step of patterning the second thin film conductor to form a second conductor wiring.
[0039]
According to the means (3), the second thin film conductor is formed on the insulating substrate to form the second thin film conductor after the predetermined position of the insulating substrate on which the first thin film conductor is formed is depressed. When the surface treatment (polishing) of the insulating substrate is performed in the forming step, the first thin film conductor in the depressed portion is exposed, and when the second thin film conductor is formed, the first thin film conductor is formed in the depressed portion. The thin film conductor and the second thin film conductor are in direct contact. Therefore, unlike the prior art, the first conductor wiring and the second conductor wiring can be electrically connected without forming the via hole and through-hole plating, and the manufacturing process of the wiring board Thus, the manufacturing cost of the wiring board can be reduced.
[0040]
In the means (3), as in the means (2), the insulating substrate is heated and softened in the vicinity of the glass transition temperature Tg, for example, and the mold is pressed and pressurized. Thus, the insulating substrate can be easily depressed.
[0041]
Further, the method of sinking the insulating substrate is not limited to the method of pressing the pushing jig in a state where the insulating substrate is heated and softened. For example, the insulating substrate is thermally cured at an intermediate stage of the curing reaction. A method is also conceivable in which a B resin is completely cured after a predetermined position is depressed by the pushing jig using a functional resin (B stage resin).
[0042]
(4) forming a first thin film conductor on one main surface of the insulating substrate; sinking a predetermined position of the insulating substrate on which the first thin film conductor is formed; and in a recessed region of the insulating substrate. A step of opening, a second thin-film conductor on a main surface facing the main surface on which the first thin-film conductor of the insulating substrate is formed, and an opening of the insulating substrate after opening in the recessed region of the insulating substrate A wiring board comprising: forming a through-hole plating; and patterning the first thin film conductor to form a first conductor wiring, and patterning the second thin film conductor to form a second conductor wiring. It is a manufacturing method.
[0043]
According to the means of (4), when a predetermined position of the insulating substrate on which the first thin film conductor is formed is depressed, the via hole is formed when the insulating substrate is opened to form a via hole. Smear is less likely to occur on the inner wall, and it is possible to prevent the connection reliability from being lowered due to the smear when the through-hole plating is formed in the same manner as the means (2).
[0044]
Further, when the second thin film conductor is formed by forming a via hole in the depressed region after the predetermined position of the insulating substrate is depressed as in the means of (4), The contact area between the second thin film conductor and the first thin film conductor can be made uniform, and the connection reliability between the first conductor wiring and the second conductor wiring, the wiring board, compared with the means (3) The electrical characteristics can be improved.
[0045]
In the means (4), as in the means (2), the insulating substrate is heated and softened in the vicinity of the glass transition temperature Tg, for example, and the mold is pressed and pressurized. Thus, the insulating substrate can be easily depressed.
[0046]
Further, the method of sinking the insulating substrate is not limited to the method of pressing the pushing jig in a state where the insulating substrate is heated and softened. For example, the insulating substrate is thermally cured at an intermediate stage of the curing reaction. A method is also conceivable in which a B resin is completely cured after a predetermined position is depressed by the pushing jig using a functional resin (B stage resin).
[0047]
Hereinafter, the present invention will be described in detail together with embodiments (examples) with reference to the drawings.
[0048]
In all the drawings for explaining the embodiments, parts having the same function are given the same reference numerals, and repeated explanation thereof is omitted.
[0049]
DETAILED DESCRIPTION OF THE INVENTION
(Example 1)
1 to 4 are schematic views showing a schematic configuration of a wiring board according to a first embodiment of the present invention. FIG. 1 is a plan view of the entire wiring board, and FIG. 2 is a partially enlarged plan view of a region X in FIG. 3 is a cross-sectional view taken along the line AA ′ in FIG. 2, and FIG. 4 is a partially enlarged view around the through hole in FIG.
[0050]
1, 2, 3, and 4, 1 is an insulating substrate, 1A is a first main surface of the insulating substrate, 1B is a second main surface of the insulating substrate, 1C is an opening (via hole), 201 is 1st conductor wiring, 202 is 2nd conductor wiring, 3 is a plating layer, 3A is through-hole (through-hole plating), A1, A2, A3, A4, and A5 are each the area | region which mounts an electronic component, T1 is an insulated substrate The thickness, T2, is the thickness of the portion of the insulating substrate where the through hole is provided.
[0051]
As shown in FIGS. 1, 2, and 3, the wiring board according to the first embodiment includes a first conductor wiring 201 provided on the first main surface 1 </ b> A of the insulating substrate 1. A double-sided wiring board in which a second conductor wiring 202 is provided on a second main surface 1B opposite to one main surface 1A, and the first conductor wiring 201 and the second conductor wiring 202 are provided at predetermined positions. They are electrically connected by through-hole plating 3A provided on the inner wall of the via hole 1C. A plating layer is provided on the surfaces of the first conductor wiring 201 and the second conductor wiring 202 to prevent oxidation of the first conductor wiring 201 and the second conductor wiring 202 and to improve the connectivity of electronic components. 3 is provided, and in the wiring board of the present embodiment, a portion provided on the inner wall of the via hole 1C of the plating layer 3 is a through hole 3A.
[0052]
Moreover, in the wiring substrate of the first embodiment, the insulating substrate 1 is, for example, a glass epoxy substrate or a polyimide substrate, and as shown in FIGS. 3 and 4, the portion provided with the through hole 3A, In other words, the portion provided with the via hole 1C is depressed. 3 and 4, the thickness of the recessed portion of the insulating substrate 1 is emphasized for easy understanding of the configuration. However, in actuality, the thickness of the portion where the through hole 3A is provided is shown. The outside, in other words, the original thickness T1 of the insulating substrate 1 is about 0.1 mm to 0.3 mm, and the thickness T2 of the portion provided with the through hole 3A is 0.05 mm or less.
[0053]
In the wiring board of the first embodiment, the through hole 3A that electrically connects the first conductor wiring 201 and the second conductor wiring 202 has the first hole as shown in FIGS. Made of the same material (plating layer) as the plating layer 3 provided on the surfaces of the conductor wiring 201 and the second conductor wiring 202, for example, gold (Au) plating is laminated with nickel (Ni) plating as a base. Is. Further, the thickness of the plating layer 3 and the through hole 3A is, for example, about 3 μm for the nickel plating layer and about 0.1 μm for the gold plating layer. 3 and 4, in order to make the configuration of the portion provided with the through hole 3A easy to understand, the thickness of the insulating substrate 1, the thickness of the first wiring conductor 201, and the second wiring conductor 202 are shown. In addition, the thickness of the plating layer 3 is shown different from the actual thickness.
[0054]
The wiring substrate of the first embodiment is a multichip module in which, for example, a semiconductor chip, a semiconductor device (semiconductor package) such as a CSP (Chip Size Package) or BGA (Ball Grid Array), and electronic components such as a capacitor or a resistor are mounted. (MCM) is a wiring board for manufacturing an electronic device, and the connection terminal of each electronic component is the first conductor wiring in each of the regions A1, A2, A3, A4, A5 shown in FIG. 201 is connected.
[0055]
Further, as shown in FIG. 1, the first conductor wiring 201 is used as an external terminal for connection between terminals of the respective electronic components, or for application of a power supply voltage or an input signal to the respective electronic components, or for output. When the number of terminals of the electronic component to be mounted is large and the number of wirings is increased, the second conductor is formed on the second main surface 1B of the insulating substrate 1 as shown in FIGS. 2 and 3, for example. Wiring 202 is provided to provide an efficient wiring pattern.
[0056]
FIGS. 5 to 7 are schematic views for explaining a method of manufacturing the wiring board of the first embodiment, and FIG. 5A is a tape with double-sided copper foil used for manufacturing the wiring board of the first embodiment. 5B is a schematic cross-sectional view taken along the line BB ′ of FIG. 5A, and FIG. 6A is a schematic plan view of one manufacturing process of the wiring board of the first embodiment. 6B is a schematic cross-sectional view taken along the line CC ′ of FIG. 6A, and FIGS. 7A and 7B are schematic cross-sectional views in each manufacturing process. This corresponds to a cross-sectional view taken along line CC ′ in FIG. 5-7, 2A is a first thin film conductor, 2B is a second thin film conductor, 2A 'is a burr, 401 is a flat plate, 402 is a pushing jig, 501 is a lower mold (die), and 502 is an upper part. The mold (punch), B1, B2, and B3 are positions for forming via holes, respectively.
[0057]
Hereinafter, the manufacturing method of the wiring board according to the first embodiment will be described with reference to FIGS.
[0058]
First, as shown in FIGS. 5A and 5B, a first thin film conductor 2A is formed on the first main surface 1A of the insulating substrate 1, and is opposed to the first main surface of the insulating substrate 1. A double-sided copper-clad laminate in which a second thin film conductor 2B is formed on the second main surface 1B is prepared.
[0059]
In the wiring board of Example 1, a glass cloth base copper clad laminate such as a glass cloth base epoxy resin copper clad laminate is used as the double-sided copper clad laminate, for example, FIG. As shown in FIG. 5B, a first main body of the insulating substrate 1 (glass epoxy substrate) in which a glass cloth woven with fibrous glass yarns 101 is used as a base material and the glass cloth is impregnated with an epoxy resin 102 is used. A surface in which a thin film conductor 2 such as a copper foil is bonded to each of the surface 1A and the second main surface 1B is prepared. At this time, the thickness of the insulating substrate 1 is about 0.3 mm.
[0060]
In the first embodiment, the glass epoxy base substrate in which the glass cloth base material woven with the glass yarn 101 is impregnated with the epoxy resin 102 is used. Sheets made of glass fabric base material impregnated with imide resin, BT resin (Bismaleimide Triazine resin), PPE resin (Poly Phenylene Ethel resin), etc., or short fiber glass yarns entangled instead of the glass cloth For example, a glass non-woven fabric impregnated with epoxy resin 102 or the like is used as a base material. In addition, one using paper as a base material or a single material having no base material inside such as polyimide resin is used.
[0061]
Next, for example, as shown in FIG. 6A, a predetermined position of the double-sided copper-clad laminate in which the first thin film conductor 2A and the second thin film conductor 2B are formed on both main surfaces of the insulating substrate 1, in other words, The positions B1, B2, and B3 where the via holes are opened are depressed.
[0062]
At this time, for example, the double-sided copper-clad laminate is arranged on a flat plate-shaped mold 401 as shown in FIG. 6B, and, for example, a mold in which the tip end portion 402A is processed into a hemisphere (push-in) When the jig) 402 is pressed against each of the positions B1, B2, and B3 where the via holes are opened, the epoxy resin 102 under the pushing jig 402 is pushed out and depressed.
[0063]
At this time, when a glass epoxy substrate is used as the insulating substrate 1, for example, the temperature of the glass epoxy substrate 1 is heated from 170 degrees to 180 degrees, and the indentation treatment is performed at a pressure of about 100 MPa, for example. The tool 402 is pushed in and depressed. In addition, the thickness of the insulating substrate 1 at each position B1, B2, B3, which is depressed using the pushing jig 402, is set to about 0.05 mm or less.
[0064]
At this time, the epoxy resin 102 is softened by heating the double-sided copper-clad laminate to a predetermined temperature, for example, 170 ° C. to 180 ° C., which is near the glass transition temperature of the epoxy resin 102. Since the fluidity becomes high, the epoxy resin 102 can be easily pushed out and depressed when the pushing jig 402 is pushed.
[0065]
Further, the positions B1, B2, and B3 to be depressed using the pushing jig 402 are through holes 3A as shown in FIG. 1 or 2, in other words, vias for forming the through holes 3A. Since it is a position where the hole 1C is formed, as shown in FIG. 6A, for example, a region where the glass yarn 101 does not exist as in the position B1, or a case where the glass yarn 101 is partially covered as in the position B2. Alternatively, there may be a case where it is on the glass thread 101 as in the position B3. Therefore, for example, as shown in FIG. 6B, if the tip end portion 402A of the pushing jig 402 is processed into a hemispherical shape, the positions B2 and B3 shown in FIG. When the pushing jig 402 is pressed onto the glass yarn 101 in the insulating substrate 1, the glass yarn 101 is pushed into the pushing jig as shown in FIGS. 6 (a) and 6 (b). Along the spherical surface of the front end portion 402A of 402, it is pushed outside the pushing jig 402, in other words, outside the positions B2 and B3 to be depressed. Therefore, the positions B1, B2, and B3 where the insulating substrate 1 is depressed are not in the glass yarn 101 and only in the epoxy resin 102 as shown in FIG.
[0066]
Next, as shown in FIG. 7A, for example, the double-sided copper-clad laminate in which a predetermined position is depressed by the pushing jig is arranged on a lower die (die) 501 having an opening at a predetermined position. Then, after aligning the depressed position with the opening of the lower mold 501, the upper mold (punch) 502 is moved down to within the depressed area of the double-sided copper-clad laminate (insulating substrate 1). A via hole 1C is formed. At this time, since the thickness of the portion where the via hole 1C of the insulating substrate 1 is formed is as thin as about 0.05 mm, the first thin film conductor 2A generated when the upper mold 502 is punched out is used. Due to the burr 2A ′, the first thin film conductor 2A on the first main surface 1A side of the insulating substrate 1 and the second thin film conductor 2B on the second main surface 1B side are in partial contact with each other.
[0067]
Further, by thinning the region of the insulating substrate 1 where the via hole 1C is formed, it is possible to perform punching with a weak force, and to the inner wall of the via hole 1C due to friction between the insulating substrate 1 and the upper mold 502. Prevents smear from occurring. Further, when a glass epoxy substrate is used as the insulating substrate 1 as in the first embodiment, as shown in FIG. 6A, when the glass epoxy substrate is depressed using the pushing jig 402, the glass Since the thread 101 is pushed out of the area where the via hole 1C is formed, when the via hole 1C is formed, as shown in FIGS. 29 (a) and 29 (b), the via hole It is possible to prevent the glass yarn 101 from protruding into 1C and becoming burrs, and the glass yarn 101 from breaking inside to form a cavity.
[0068]
Further, the step of forming the via hole 1C is not limited to the method of forming by punching using the upper mold 502 and the lower mold 502, and for example, formed by laser processing using a carbon dioxide laser, excimer laser, or the like. May be.
[0069]
Next, as shown in FIG. 7B, a resist film (not shown) for forming a wiring pattern is formed on the first thin film conductor 2A and the second thin film conductor 2B, and the resist film is used as a mask. Etching is performed to form the first conductor wiring 201 and the second conductor wiring 202.
[0070]
Thereafter, the resist film is removed, and a plating layer 3 is formed on the surfaces of the first conductor wiring 201 and the second conductor wiring. At this time, the plating layer 3 is also formed as the through-hole plating 3A on the inner wall of the via hole 1C, so that a wiring board with the through-hole 3A portion depressed as shown in FIG. 3 can be obtained. The plating layer 3 and the through hole 3A are formed by laminating a nickel plating layer and a gold plating layer using, for example, the electroless plating method or the electrolytic plating method, and the nickel plating layer is about 3 μm. The gold plating layer is formed to a thickness of about 0.1 μm.
[0071]
FIG. 8 is a schematic diagram for explaining the function and effect of the wiring board of the first embodiment. FIG. 8A is an enlarged cross-sectional view around the through hole of the wiring board of the first embodiment, and FIG. ) Is an enlarged cross-sectional view around a through hole of a conventional wiring board.
[0072]
As shown in FIG. 8B, the conventional wiring board has a plate thickness of about 0.3 mm at the portion where the through hole is provided, in other words, the portion where the via hole 1C is formed. Unless a thin copper plating layer is formed on the inner wall of the via hole 1C, the through-hole plating 203A cannot be formed in the insulating region of the inner wall of the via hole 1C. By reducing the thickness of the via hole 1C, the through hole 3A is formed in the via hole 1C using the burr 2A 'of the first thin film conductor 2A as shown in FIG. be able to. Therefore, the conventional process of forming electroless copper plating can be omitted, and the manufacturing cost can be reduced.
[0073]
Further, in the conventional wiring board, the thickness of the portion where the via hole 1C is formed is about 0.3 mm, and the stress applied to the through-hole plating 203A is large when the insulating substrate 1 is thermally expanded in the thickness direction. Since the through-hole plating 203A is likely to be cracked or peeled off, for example, a copper plating layer 203A having a thickness of about 7 μm to 8 μm is formed as a through-hole. However, like the wiring board of the first embodiment, By making the thickness of the insulating substrate 1 in the portion where the via hole is formed as very thin as about 0.05 mm, for example, it is less likely to be affected by thermal expansion in the thickness direction of the glass epoxy substrate. Can do. Therefore, it is possible to prevent a decrease in connection reliability due to thermal expansion in the plate thickness direction of the insulating substrate 1 without increasing the thickness of the through-hole plating by performing electroless copper plating and electroplating as in the prior art.
[0074]
Further, as in the wiring board of the first embodiment shown in FIG. 8A, by reducing the thickness of the portion where the via hole 1C is formed, it is difficult to be affected by thermal expansion. The through-hole plating 3 </ b> A can be formed with the plating layer 3 without forming the copper plating layer 203 as in a conventional wiring board. Therefore, the diameter d1 of the via hole 1C of the wiring board of the first embodiment can be made smaller than the diameter d3 of the via hole 1C of the conventional wiring board shown in FIG. 8B. Further, since the diameter of the via hole 1C can be reduced, the area d2 necessary for forming the through hole can be made smaller than the area d4 for forming the conventional through hole, and the wiring can be miniaturized and the wiring density can be increased. And miniaturization of the wiring board.
[0075]
9 and 10 are schematic views showing a schematic configuration of an electronic device using the wiring board of the first embodiment, FIG. 9 is a schematic plan view of the electronic device, and FIG. 10 is a DD ′ line in FIG. FIG.
[0076]
The wiring board according to the first embodiment as shown in FIG. 1 is used for manufacturing an electronic device such as a multichip module (MCM), for example, and a plurality of semiconductor chips as shown in FIGS. The electronic components C1, C2, C3, C4, and C5 such as a semiconductor package are mounted on each area on the wiring board, and the connection terminal C3A of the semiconductor chip C3 and the first conductor wiring 201 are, for example, Input / output of signals between the mounted electronic components by the first conductor wiring 201 and the second conductor wiring 202 connected by the first conductor wiring 201 and the through-hole 203B by the gold bump 6. And have a single function.
[0077]
At this time, for example, a wiring protective film (permanent mask) 7 such as a solder resist is applied to the outside of the region on which the electronic component is mounted on the first main surface of the wiring board 1 and the second main surface. Then, a thermosetting resin 8 such as an epoxy resin is poured between each electronic component and the wiring board to perform underfill sealing.
[0078]
As described above, according to the first embodiment, the via hole 1C is formed before the via hole 1C is formed at a predetermined position of the double-sided copper-clad laminate in which the thin film conductors are formed on both main surfaces of the insulating substrate 1. When the via hole 1C is formed, smear is generated on the inner wall of the via hole 1C because the portion of the insulating substrate 1 where the via hole 1C is formed becomes thin. I can prevent it. Therefore, when the through-hole plating 203B is formed in the via hole 1C, plating defects due to smear can be prevented, and the connection reliability of the through-hole 203B can be improved.
[0079]
Further, at the position where the via hole 1 </ b> C is formed, for example, the pressing jig 402 is pressed against the double-sided copper-clad laminate and pressed to push the insulating substrate 1 to the outside of the pressing jig 402. Can be easily depressed. Further, the insulating jig 1 is heated to a predetermined temperature, for example, near the glass transition temperature of the insulator constituting the insulating substrate 1, so that the insulator softens and has high fluidity. When 402 is pushed in, it can be easily depressed with a weak force.
[0080]
Further, even when the glass epoxy insulating substrate 1 in which the glass cloth is impregnated with the epoxy resin 102 is used as in the wiring board of the first embodiment, it is shown in FIGS. 6 (a) and 6 (b). As described above, by pushing out the glass yarn 101 at the position where the via hole 1C is to be formed using the pushing jig 402, it is possible to prevent glass burrs from remaining in the via hole 1C when the via hole 1C is formed. Therefore, when the through-hole plating 203B is formed in the via hole 1C, it is possible to prevent the pinhole from being opened or cracked by the glass burr and to improve the connection reliability of the through-hole 203B.
[0081]
Further, since the glass yarn 101 is extruded outside the position where the via hole 1C is formed, migration in which the plated conductor precipitates along the glass yarn 101 is less likely to occur when the through-hole plating 203 is formed. It is possible to prevent a decrease in electrical reliability due to a short between conductor wires.
[0082]
Further, by thinning the insulating substrate 1 by thinning it, a thin film on the first main surface 1A side of the insulating substrate 1 is formed by a thin film conductor (copper foil) burr 2 ′ formed when the via hole 1C is formed. The conductor 2A and the thin film conductor 2B on the second main surface 1B side are in partial contact with each other, and a thin plating layer is formed in advance on the inner wall of the via hole 1C using an electroless plating method as in the prior art. Even if not, a plated layer grows from the portion of the burr 2 ′, and the through-hole plating 203B can be formed on the inner wall of the via hole 1C. Therefore, the manufacturing process of the wiring board can be reduced.
[0083]
Further, by making the insulating substrate 1 depressed and thin, the thermal expansion of the insulating substrate 1 around the via hole 1C is reduced, and the thermal expansion in the plate thickness direction of the insulating substrate 1 leads to the through hole 203B. Since such a load is reduced, for example, through-hole connection can be made by the plating layer 203A formed on the surfaces of the first conductor wiring 201 and the second conductor wiring 202. In this case, since it is not necessary to connect through holes with a copper plating layer having a thickness of 7 μm to 8 μm as in the prior art, the manufacturing process of the wiring board can be reduced, and the manufacturing cost can be reduced.
[0084]
Further, in the wiring board of Example 1, a glass epoxy substrate in which a glass cloth is impregnated with an epoxy resin 102 is used as the insulating substrate 1, but not limited thereto, a glass cloth or a glass nonwoven fabric, Even in the case of an insulating substrate made of a composite material impregnated with an insulating resin, or an insulating substrate made of a single material such as a polyimide tape, the position where the via hole is formed is depressed, so that Similarly to the wiring board, it is possible to prevent the connection reliability of the through hole from being lowered, reduce the manufacturing process of the wiring board, and reduce the manufacturing cost.
[0085]
In the wiring board of the first embodiment, a two-layer wiring board (double-sided wiring board) in which the first conductor wiring 201 and the second conductor wiring 202 are provided on the insulating substrate 1 will be described as an example. However, the present invention is not limited to this, for example, after manufacturing a double-sided wiring board according to the procedure described in Example 1, further forming an insulator layer and a conductive wiring layer on the surface of the double-sided wiring board, A multilayer wiring board having three or more conductor wiring layers can also be formed.
[0086]
Further, in the method of manufacturing the wiring board according to the first embodiment, the predetermined position of the double-sided copper-clad laminate (insulating substrate 1) is depressed using the pressing jig 402 whose tip portion 402A is processed into a hemispherical shape. Needless to say, the tip of the pushing jig 402 may have any shape.
[0087]
FIG. 11 is a schematic cross-sectional view showing a modification of the wiring board of Example 1, and shows a cross-sectional view corresponding to the cross-sectional view of FIG.
[0088]
In the wiring board of the first embodiment, as shown in FIG. 3 or FIG. 8A, the nickel plating layer and the gold plating layer formed on the surface of the first conductor wiring 201 and the second conductor wiring 202 are provided. The through hole 3A is formed by the laminated plating layer 3. However, the present invention is not limited to this. For example, as shown in FIG. 11, a copper plating layer 203 using an electroplating method is formed before the plating layer 3 is formed. The through hole 203A may be formed by the copper plating layer 203, and the plating layer 3A may be formed on the surface of the through hole 203A. In this case, as shown in FIG. 7A, after forming via holes in the recessed portions of the double-sided copper clad laminate, the surfaces of the first thin film conductor 2A and the second thin film conductor 2B, and the vias are formed. For example, the copper plating layer 203 (203A) is formed on the inner wall of the hole 1C by using an electroplating method, and the copper plating layer 203, the first thin film conductor 2A, and the second thin film conductor 2B are etched. The plating layer 3 is formed. At this time, the diameter d4 of the via hole 1C is larger than the diameter d1 of the via hole 1C of the wiring board of the first embodiment. However, the insulating substrate 1 in the portion where the via hole 1C is formed is depressed and thinned. Accordingly, it is possible to prevent smear from being generated on the inner wall of the via hole 1C and to prevent the connection reliability of the through hole 203A from being lowered, similarly to the wiring board of the first embodiment. In addition, the copper plating layer 203 can be formed without forming a thin copper plating layer by using an electroless plating method as in the prior art, thereby simplifying the manufacturing process and reducing the manufacturing cost of the wiring board. Can be made.
[0089]
(Example 2)
FIG. 12 is a schematic diagram showing a schematic configuration of the wiring board according to the second embodiment of the present invention. The overall configuration of the wiring board of the second embodiment is the same as that of the wiring board of the first embodiment, and FIG. 12 shows an enlarged sectional view around the through hole.
[0090]
The overall schematic configuration of the wiring board of the second embodiment is the same as that of the wiring board described in the first embodiment, and a detailed description thereof will be omitted.
[0091]
The wiring board according to the second embodiment is different from the wiring board according to the first embodiment in that, as shown in FIG. 12, the portion of the insulating board 1 where the through hole 3A is provided is the first part of the insulating board 1. Both the first main surface 1A side and the second main surface 1B side are depressed.
[0092]
FIG. 13 is a schematic diagram for explaining the method of manufacturing the wiring board according to the second embodiment. FIGS. 13A and 13B are cross-sectional views corresponding to FIG.
[0093]
Hereinafter, the manufacturing method of the wiring board according to the second embodiment will be described with reference to FIGS. 13A and 13B. The same steps as the manufacturing method of the wiring board according to the first embodiment will be described. While using the figure used in Example 1, detailed description thereof is omitted.
[0094]
First, as shown in FIGS. 5A and 5B, a first thin film conductor 2A is formed on the first main surface 1A of the insulating substrate 1, and the second main surface 1B of the insulating substrate 1 is formed. A double-sided copper clad laminate on which the second thin film conductor 2B is formed is prepared. Also in the wiring substrate of the second embodiment, the insulating substrate 1 is a glass epoxy substrate in which a glass cloth woven with glass yarn 101 is impregnated with an epoxy resin 102 as in the first embodiment. Shall.
[0095]
Next, as shown in FIG. 13 (a), the double-sided copper-clad laminate is provided with pushing jigs 402 and 403 arranged on the first main surface side and the second main-surface side of the double-sided copper-clad laminate, respectively. And press it into the depressed position.
[0096]
At this time, the pushing jigs 402 and 403 are arranged so as to face each other, and the pushing jigs 402 and 403 are positioned only on the epoxy resin 102 as shown in FIG. B1, the glass yarn 101 is pushed in at any one of a position B2 where the glass yarn 101 is partially applied and a position B3 on the glass yarn 101. Therefore, as described in the first embodiment, the tip portions of the respective pushing jigs 402 and 403 are processed into a hemispherical shape, so that when the pushing jigs 402 and 403 are pushed in, they are depressed. The glass yarn 101 at the position to be pushed is pushed out, and the depressed positions B1, B2, B3 are in a state of only the epoxy resin 102.
[0097]
Next, via holes 1C are formed in the recessed positions of the double-sided copper-clad laminate by, for example, punching using a die or laser processing, and the first thin film conductor 2A and the second thin film conductor 2B are formed. Etching is performed to form the first conductor wiring 201 and the second conductor wiring 202 as shown in FIG.
[0098]
Thereafter, a plating layer 3 in which, for example, a nickel plating layer and a gold plating layer are laminated is formed on the surfaces of the first conductor wiring 201 and the second conductor wiring 202. At this time, the plating layer 3 is also formed on the inner wall of the via hole 1C, and the plating layer formed on the inner wall of the via hole 1C is used as the through hole 3A.
[0099]
As described above, also in the wiring board of the second embodiment, similarly to the wiring board of the first embodiment, the position where the via hole 1C is formed is depressed, so that the inner wall of the via hole 1C is formed. It is possible to prevent the occurrence of smear and to prevent the connection reliability of the through hole 3A from being lowered due to the smear.
[0100]
Further, by reducing the thickness of the insulating substrate 1 by sinking the position where the via hole 1C is formed, the influence of thermal expansion in the thickness direction around the via hole of the insulating substrate 1 can be reduced, so that the connection is made. The reliability is improved, and it is possible to form the through-hole 3A with the plating layer 3, and it is not necessary to form the copper plating layer 203A by using an electroless plating method and an electroplating method as in the prior art. The manufacturing process is simplified, and the manufacturing cost of the wiring board can be reduced.
[0101]
FIG. 14 is a schematic diagram for explaining another function and effect of the wiring board of the second embodiment. FIG. 14A is a cross-sectional view around the through hole of the wiring board of the second embodiment, and FIG. b) is a cross-sectional view of the periphery of the through-hole of the wiring board of the first embodiment.
[0102]
In the wiring substrate of the first embodiment, only the first main surface 1A side of the insulating substrate 1 (double-sided copper-clad laminate) is depressed, but in the wiring substrate of the second embodiment, the first of the insulating substrate 1 is recessed. Since both sides of the main surface 1A side and the second main surface 1B side are depressed, as shown in FIG. 14 (a), the depth of the depressed portion, in other words, each of the pushing jigs 402, 403 As shown in FIG. 14B, the amount of pushing can be made shallower than when depressed from one side. Therefore, in the wiring board of the second embodiment, the diameter d6 of the outer periphery of the depressed portion shown in FIG. 14A is set to the outer diameter of the depressed portion of the wiring board of the first embodiment shown in FIG. It can be made smaller than d7, and can be made smaller and finer than the wiring substrate of the first embodiment.
[0103]
Further, since the depression is made from the first principal surface side 1A and the second principal surface 1B side of the double-sided copper-clad laminate, the depressed portion becomes shallower than the case of depression from one side as in the first embodiment. For this reason, deformation of the thin film conductors 2A and 2B at the outer peripheral portion of the depressed portions is reduced when they are pushed in, and the thin film conductors 2A and 2B are microcracked by the deformation at the time of pushing and the connection reliability is lowered. Can be prevented.
[0104]
(Example 3)
FIG. 15 is a schematic cross-sectional view showing a schematic configuration of a wiring board of Example 3 according to the present invention. The overall configuration of the wiring board of the third embodiment is the same as that of the wiring board of the first embodiment, and FIG. 13 shows an enlarged cross-sectional view of the through hole portion.
[0105]
Since the overall schematic configuration of the wiring board according to the third embodiment is the same as that of the wiring board described in the first embodiment, detailed description thereof is omitted.
[0106]
The wiring board according to the third embodiment is different from the wiring boards according to the first and second embodiments as shown in FIG. 15, as shown in FIG. 15, the depressed portion faces the first main surface 1 </ b> A side of the insulating substrate 1. The second main surface 1B side is reached, and the first conductor wiring 201 and the second conductor wiring 202 are directly connected. That is, in the wiring board of the third embodiment, the via holes 1C, the first conductor wiring 201, and the second conductor wiring 202 of the insulating substrate 1 are provided as in the wiring boards of the first and second embodiments. The through hole 3A to be connected is not provided.
[0107]
FIGS. 16 to 18 are schematic diagrams for explaining a method of manufacturing a wiring board according to the third embodiment. FIG. 16A illustrates a single-sided copper-clad laminate used for manufacturing the wiring board according to the third embodiment. FIG. 16B is a schematic plan view, FIG. 16B is a schematic cross-sectional view taken along the line EE ′ of FIG. 16A, and FIGS. 17A, 17B, 18A, and 18B. ) Is a schematic cross-sectional view in each manufacturing process, and corresponds to a cross-sectional view taken along line EE ′ of FIG.
[0108]
Hereinafter, the manufacturing method of the wiring board according to the third embodiment will be described with reference to FIGS.
[0109]
The wiring board of Example 3 is manufactured using, for example, a glass cloth base copper clad laminate such as a glass cloth base epoxy resin copper clad laminate. However, the glass cloth substrate epoxy resin copper clad laminate used in Example 3 is made of a glass cloth woven with fibrous glass yarn 101 as a base material as shown in FIGS. 16 (a) and 16 (b). A single-sided copper-clad laminate in which a first thin film conductor 2A such as a copper foil is bonded to one main surface of the insulating substrate 1 in which the glass cloth is impregnated with an epoxy resin 102, for example, the first main surface 1A. At this time, the thickness of the insulating substrate 1 is about 0.3 mm.
[0110]
Moreover, as the insulating substrate 1, as described in the first embodiment, a glass epoxy substrate in which a glass cloth base material is impregnated with an epoxy resin 102 is used. Glass cloth base material impregnated with glass cloth with imide resin, BT resin (Bismaleimide Triazine resin), PPE resin (PolyPhenylene Ethel resin), etc., or short fiber glass yarn instead of glass cloth A sheet or the like that is made of a glass nonwoven fabric impregnated with an epoxy resin 102 or the like is used. In addition, those using paper as a base material, polyimide resin tape having no base material inside, and the like are used.
[0111]
Next, as illustrated in FIG. 17A, for example, the predetermined position of the single-sided copper-clad laminate is depressed using the pushing jig 402 as described in the first embodiment. At this time, for example, the pushing jig 402 is depressed from the first main surface 1A side where the first thin film conductor 2A is formed. At this time, when a glass epoxy substrate is used as the insulating substrate 1, for example, the temperature of the insulating substrate 1 is changed from 170 degrees to 180 degrees, and the pushing jig 402 is set at a pressure of about 100 MPa, for example. Push and sink. At this time, the thickness of the insulating substrate 1 that is depressed by using the pushing jig 402 is set to about 0.05 mm or less.
[0112]
Since the position to be depressed using the pushing jig 402 is a position where a through hole is formed, as shown in FIG. 6A, for example, when the glass yarn 101 is not present, it is partially When it is applied to the glass yarn 101 or when it is on the glass yarn 101, as shown in FIG. 17A, when the tip 402A of the pushing jig 402 is processed into a hemispherical shape, The glass yarn 101 is pushed to the outside of the pushing jig along the spherical surface at the tip of the pushing jig, and the depressed portion of the insulating substrate 1 is free of the glass yarn and has only the epoxy resin 102. can do.
[0113]
Next, as a pretreatment for forming a second thin film conductor on the second main surface 1B side facing the first main surface 1A of the insulating substrate 1, for example, the insulating substrate is obtained by chemical polishing or mechanical polishing, for example. The second main surface 1B is polished. At this time, since the thickness of the recessed portion of the insulating substrate 1 is about 0.05 mm or less, the recessed portion of the insulating substrate 1 is opened as shown in FIG. The first thin film conductor 2A is exposed from the second main surface 1B side. In some cases, the second main surface 1B of the insulating substrate 1 may be exposed before being polished.
[0114]
Next, as shown in FIG. 18A, a second thin film conductor 2 </ b> B is formed on the second main surface 1 </ b> B side of the insulating substrate 1. For example, the second thin film conductor 2B is formed by forming a thin electroless copper plating layer (not shown) on the second main surface 1B of the insulating substrate 1, and then using the electroless copper plating layer as an electrode. 2B is formed. At this time, since the first thin film conductor 2A is exposed to the second main surface 1B side in the depressed portion of the insulating substrate 1, via holes 1C and The first thin film conductor 2A and the second thin film conductor 2B can be electrically connected without forming through-hole plating.
[0115]
Next, the first thin film conductor 2A and the second thin film conductor 2B are etched to form the first conductor wiring 201 and the second conductor wiring 202 as shown in FIG. For example, when a plating layer 3 in which a nickel plating layer and a gold plating layer are laminated is formed on the surfaces of the first conductor wiring 201 and the second conductor wiring 202, a through-hole-shaped wiring board as shown in FIG. 15 is obtained. be able to. The wiring board is the same as the wiring board of the first embodiment. For example, as shown in FIGS. 9 and 10, it is used to manufacture a multichip module by mounting a plurality of semiconductor chips.
[0116]
As described above, according to the wiring board of the third embodiment, the single-sided copper-clad laminate in which the first thin film conductor 2A is formed on the first main surface 1A of the insulating substrate 1 is depressed and thinned. The second main surface 1B of the insulating substrate 1 facing the first main surface 1A is polished to expose the first thin film conductor 2A, whereby the second thin film conductor 2B is exposed on the second main surface 1B of the insulating substrate 1. The first thin film conductor 2A and the second thin film conductor 2B are electrically connected. Therefore, the step of forming the via hole 1C and the through hole 3A can be omitted as in the conventional wiring board or the wiring boards of the first and second embodiments, and the manufacturing cost of the wiring board is further reduced. be able to.
[0117]
Further, in the wiring boards of the first and second embodiments, since the via hole 1C is formed, a slight smear occurs. Therefore, there is a possibility that the connection reliability due to the smear may be lowered. However, in the wiring board of the third embodiment, the via hole 1C is not formed, so that the smear does not occur. Therefore, connection reliability is improved as compared with the connection through the through hole 3A (via hole 1C).
[0118]
FIG. 19 is a schematic cross-sectional view showing a modification of the method of manufacturing the wiring board according to the third embodiment.
[0119]
In the wiring board of Example 3, the single-sided copper-clad laminate was depressed using the push-in jig 402, and then the second main surface 1B side of the insulating substrate 1 was polished to form the first thin film conductor 2A. However, the present invention is not limited to this. For example, the pushing amount and the load of the pushing jig 402 are increased, and as shown in FIG. It is also possible to extrude. However, in this case, depending on the accuracy of the pushing jig 402, it is possible that the exposed area at the plurality of positions to be depressed varies or is not exposed. However, as described in the third embodiment, the insulating substrate A predetermined area can be exposed by polishing performed as a pretreatment when forming the second thin film conductor 2B on one second main surface 1B.
[0120]
FIG. 20 is a schematic view for explaining another modified example of the method of manufacturing the wiring board according to the third embodiment, and FIGS. 20A and 20B are cross-sectional views in respective steps.
[0121]
As shown in FIG. 17, the wiring board of the third embodiment has the surface on which the first thin film conductor 2 </ b> A of the single-sided copper-clad laminate is depressed, but is not limited thereto. As shown to (a), you may dent the 2nd main surface 1B side facing the 1st main surface 1A in which the said 1st thin film conductor 2A of the said insulated substrate 1 was formed. Also in this case, when the insulating substrate 1 is polished by the pretreatment for forming the second thin film conductor on the second main surface 1B of the insulating substrate 1 after being depressed by the pushing jig 402, By exposing the first thin film conductor 2A, the first conductor wiring 201 and the second conductor wiring 202 can be connected without forming the via hole 1C and the through hole 3A, thereby reducing the manufacturing cost. Connection reliability is improved.
[0122]
21 and 22 are schematic views for explaining another modified example of the method of manufacturing the wiring board according to the third embodiment. FIGS. 21 (a), 21 (b), 22 (a), And FIG.22 (b) is sectional drawing in each process, respectively.
[0123]
As shown in FIG. 17, the wiring board of Example 3 has the surface on which the first thin film conductor 2 </ b> A of the single-sided copper-clad laminate is depressed, but is not limited thereto. As shown to (a), you may dent the 2nd main surface 1B side facing the 1st main surface 1A in which the said 1st thin film conductor 2A of the said insulated substrate 1 was formed. In this case, after being depressed by the pushing jig 402, via holes 1C are formed in the depressed position of the insulating substrate 1 by laser processing using, for example, a carbon dioxide laser or an excimer laser, as shown in FIG. As shown in FIG. 22A, the second thin film conductor 2B is formed on the second main surface 1B of the insulating substrate 1 by using an electroless plating method and an electroplating method, and the via hole 1C is formed. After the thin film conductor is embedded and connected to the first thin film conductor 2A, the first thin film conductor 2A and the second thin film conductor 2B are etched to form the first conductor wiring 201 and the second conductor wiring 202. However, as shown in FIG. 22B, the plating layer 3 may be formed on the surfaces of the first conductor wiring 201 and the second conductor wiring 202.
[0124]
In this case, unlike the third embodiment, the via hole 1C must be formed. However, in order to embed a thin film conductor in the via hole and connect the first conductor wiring 201 and the second conductor wiring 202, As described in the first and second embodiments, the connection reliability is improved as compared with the case where the connection is made only through the through hole 3A formed by the plating layer 3.
[0125]
(Example 4)
In the first to third embodiments, as a method of sinking the region where the through hole of the insulating substrate 1 is formed, the insulating substrate 1 is heated and softened, and the columnar pushing jig 402 is pushed in. In the fourth embodiment, an example in which the insulating substrate 1 is depressed using another method will be described.
[0126]
In the fourth embodiment, the wiring board of the first embodiment is taken as an example and the manufacturing method thereof will be described. However, the description of the same parts as those of the wiring board manufacturing method of the first embodiment is omitted. .
[0127]
In the wiring board of the fourth embodiment, for example, as shown in FIGS. 5A and 5B, a glass cloth woven with fibrous glass yarn 101 is used as a base material, and the epoxy resin 102 is applied to the glass cloth. A glass cloth base copper clad laminate in which a thin film conductor 2 such as a copper foil is bonded to each of the first main surface 1A and the second main surface 1B of the insulating substrate 1 (glass epoxy-based substrate) impregnated with copper is used. However, at this time, the epoxy resin 102 impregnated in the glass cloth is not completely cured, but is kept at an intermediate stage of the curing reaction.
[0128]
Next, for example, as shown in FIG. 6A, a predetermined position of the double-sided copper-clad laminate in which the first thin film conductor 2A and the second thin film conductor 2B are formed on both main surfaces of the insulating substrate 1, in other words, The positions B1, B2, and B3 where the via holes are opened are depressed.
[0129]
At this time, for example, the double-sided copper-clad laminate is arranged on a flat plate-shaped mold 401 as shown in FIG. 6B, and, for example, a mold in which the tip end portion 402A is processed into a hemisphere (push-in) When the jig) 402 is pressed against each of the positions B1, B2, and B3 where the via holes are opened, the epoxy resin 102 under the pushing jig 402 is pushed out and depressed.
[0130]
At this time, since the epoxy resin 102 of the insulating substrate 1 is an intermediate stage (B-stage resin) of the curing reaction, the fluidity is high, and the insulating substrate 1 is formed as described in the first to third embodiments. Without being heated, the indentation jig 402 can be depressed only by pressing and pressing. Further, since the fluidity is better than when the completely cured epoxy resin is heated, it can be depressed with a weaker load than the methods described in the first to third embodiments.
[0131]
After the predetermined position of the insulating substrate 1 is depressed, for example, the double-sided copper-clad laminate is heated at 170 to 180 ° C. for about 90 minutes to completely cure the epoxy resin.
[0132]
Next, as shown in FIG. 7A, for example, the double-sided copper-clad laminate in which a predetermined position is depressed by the pushing jig is arranged on a lower die (die) 501 having an opening at a predetermined position. Then, after aligning the depressed position with the opening of the lower mold 501, the upper mold (punch) 502 is moved down to within the depressed area of the double-sided copper-clad laminate (insulating substrate 1). A via hole 1C is formed.
[0133]
Next, as shown in FIG. 7B, a resist film (not shown) for forming a wiring pattern is formed on the first thin film conductor 2A and the second thin film conductor 2B, and the resist film is used as a mask. Etching is performed to form the first conductor wiring 201 and the second conductor wiring 202.
[0134]
Thereafter, the resist film is removed, and a plating layer 3 is formed on the surfaces of the first conductor wiring 201 and the second conductor wiring. At this time, the plating layer 3 is also formed as the through-hole plating 3A on the inner wall of the via hole 1C, so that a wiring board with the through-hole 3A portion depressed as shown in FIG. 3 can be obtained. The plating layer 3 and the through hole 3A are formed by laminating a nickel plating layer and a gold plating layer using, for example, the electroless plating method or the electrolytic plating method, and the nickel plating layer is about 3 μm. The gold plating layer is formed to a thickness of about 0.1 μm.
[0135]
As described above, according to the method of manufacturing the wiring board of the fourth embodiment, the position where the via hole 1C of the insulating substrate is formed is depressed, as in the wiring board described in the first embodiment. A wiring board with high through-hole connection reliability can be manufactured, and the manufacturing process can be simplified to reduce the manufacturing cost of the wiring board.
[0136]
Further, as in the method of manufacturing the wiring board according to the fourth embodiment, a thermosetting resin is used for the insulating substrate, the curing reaction of the thermosetting resin is stopped at an intermediate stage, and the pushing jig is used in that state. By causing the predetermined position to be depressed by 402, it is possible to cause the depression to be depressed at a lower temperature and with a weaker load than the manufacturing method described in the first embodiment.
[0137]
In the fourth embodiment, the wiring board described in the first embodiment is described as an example. However, the present invention is not limited to this, and the manufacturing of the wiring board as described in the second and third embodiments is not limited thereto. It goes without saying that it can be applied to the method. The insulating substrate is not limited to a glass cloth impregnated with an epoxy resin, and may be a single substrate using only an epoxy resin or a modified epoxy resin, for example.
[0138]
The present invention has been specifically described above based on the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. .
[0139]
【The invention's effect】
The effects obtained by typical ones of the inventions disclosed in the present invention will be briefly described as follows.
[0140]
(1) In a wiring board in which conductor wiring is formed on both surfaces of an insulating substrate and the conductor wiring is connected by through holes, connection reliability of the through holes can be improved.
[0141]
(2) In the wiring board in which the conductor wiring is formed on both surfaces of the insulating substrate and the conductor wiring is connected through the through hole, the manufacturing process of the wiring board can be simplified.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a schematic configuration of a wiring board according to a first embodiment of the present invention.
2 is a schematic diagram illustrating a schematic configuration of the wiring board according to the first embodiment, and is a partially enlarged view of FIG. 1; FIG.
3 is a schematic diagram illustrating a schematic configuration of the wiring board according to the first embodiment, and is a schematic cross-sectional view taken along line AA ′ of FIG. 2; FIG.
4 is a schematic diagram illustrating a schematic configuration of the wiring board according to the first embodiment, and is a partially enlarged view of FIG. 3;
FIG. 5 is a schematic diagram for explaining a method for manufacturing a wiring board according to the first embodiment. FIG. 5A is a schematic plan view showing a schematic configuration of a tape material used for manufacturing the wiring board according to the first embodiment. FIG. 5 and FIG. 5B are schematic cross-sectional views taken along the line BB ′ of FIG.
6A and 6B are schematic views for explaining a method of manufacturing a wiring board according to the first embodiment, in which FIG. 6A is a schematic plan view in one manufacturing process, and FIG. 6B is FIG. It is a schematic cross section in the CC 'line.
7A and 7B are schematic views for explaining a method for manufacturing a wiring board according to the first embodiment, and FIGS. 7A and 7B are schematic cross-sectional views in respective manufacturing steps.
FIG. 8 is a schematic cross-sectional view for explaining the function and effect of the wiring board according to the first embodiment.
FIG. 9 is a schematic plan view illustrating a schematic configuration of an electronic device using the wiring board according to the first embodiment.
10 is a schematic diagram illustrating a schematic configuration of an electronic device using the wiring board according to the first embodiment, and is a cross-sectional view taken along line DD ′ of FIG.
11 is a schematic cross-sectional view showing a modification of the wiring board of Example 1. FIG.
12 is a schematic diagram showing a schematic configuration of a wiring board of Example 2 according to the present invention, and is an enlarged cross-sectional view around a through hole. FIG.
13A and 13B are schematic views for explaining a method of manufacturing a wiring board according to the second embodiment, and FIGS. 13A and 13B are cross-sectional views in each step.
14A and 14B are schematic views for explaining the function and effect of the wiring board according to the second embodiment. FIG. 14A is an enlarged cross-sectional view around the through hole of the wiring board according to the second embodiment, and FIG. ) Is an enlarged sectional view around the through hole of the wiring board of Example 1. FIG.
FIG. 15 is a schematic cross-sectional view showing a schematic configuration of a wiring board of Example 3 according to the present invention.
FIG. 16 is a schematic diagram for explaining a method for manufacturing a wiring board according to the third embodiment, and FIG. 16A shows a schematic configuration of a single-sided copper-clad laminate used for manufacturing the wiring board according to the third embodiment. FIG. 16B is a schematic cross-sectional view taken along the line EE ′ of FIG.
FIGS. 17A and 17B are schematic views for explaining a method of manufacturing a wiring board according to the third embodiment, and FIGS. 17A and 17B are schematic cross-sectional views in each step. FIGS.
18A and 18B are schematic views for explaining a method for manufacturing a wiring board according to the third embodiment, and FIGS. 18A and 18B are schematic cross-sectional views in respective steps.
FIG. 19 is a schematic cross-sectional view showing a modification of the method for manufacturing the wiring board according to the third embodiment.
20 is a schematic cross-sectional view for explaining a modified example of the method of manufacturing the wiring board according to the third embodiment, and FIG. 20A and FIG. 20B are cross-sectional views in respective steps.
FIG. 21 is a schematic cross-sectional view for explaining a modified example of the method of manufacturing the wiring board according to the third embodiment, and FIGS. 21 (a) and 21 (b) are cross-sectional views in the respective steps.
22 is a schematic cross-sectional view for explaining a modified example of the method of manufacturing the wiring board according to the third embodiment, and FIGS. 22 (a) and 22 (b) are cross-sectional views in the respective steps.
FIG. 23 is a schematic plan view showing a schematic configuration of a conventional electronic device.
24 is a schematic diagram showing a schematic configuration of a conventional electronic device, and is a cross-sectional view taken along the line FF ′ of FIG.
FIG. 25 is a partially enlarged plan view of a wiring board used in a conventional electronic device.
26 is a schematic diagram showing a schematic configuration of a wiring board used in a conventional electronic device, and is a cross-sectional view taken along the line GG ′ of FIG. 25.
FIGS. 27A and 27B are schematic views for explaining a conventional method of manufacturing a wiring board, and FIGS. 27A and 27B are schematic cross-sectional views in respective manufacturing steps.
FIG. 28 is a schematic diagram for explaining a problem in a conventional method of manufacturing a wiring board, in which FIG. 28 (a) is a schematic plan view of a double-sided copper clad laminate used for manufacturing the wiring board, and FIG. 28 (b). FIG. 29 is a cross-sectional view taken along line HH ′ of FIG.
29 is a schematic diagram for explaining a problem in a conventional method of manufacturing a wiring board, in which FIG. 29 (a) is a schematic plan view after forming a via hole, and FIG. 29 (b) is a schematic diagram of FIG. 29 (a). It is sectional drawing in the II 'line.
FIG. 30 is a schematic diagram for explaining a problem in the conventional method of manufacturing a wiring board, and is a cross-sectional view after forming a through hole.
[Explanation of symbols]
1 Insulating substrate
1A First main surface of insulating substrate
1B Second main surface of insulating substrate
1C via hole
101 Glass yarn
102 Insulating resin (epoxy resin)
201 First conductor wiring
202 Second conductor wiring
203 Copper plating layer
3 Plating layer
203A, 3A Through hole (through hole plating)
401 Mold on flat plate
402,403 Pushing jig
402A, 403A Pushing jig tip
501 Lower mold (die)
502 Upper die (punch)
6 Ball terminal
7 Wiring protective film (solder resist)
8 Sealing insulator
A1, A2, A3, A4, A5 Electronic component mounting area
B1, B2, B3 Via hole formation area
C1, C2, C3, C4, C5 electronic components

Claims (10)

A glass substrate impregnated with any one of an epoxy resin, an imide resin, a BT resin, and a PPE resin on a glass cloth, or a sheet formed by intertwining short fiber glass yarns was impregnated with an epoxy resin. A first conductor wiring is provided on a first main surface of an insulating substrate made of glass nonwoven fabric, a second conductor wiring is provided on a second main surface opposite to the first main surface of the insulating substrate, and the first A wiring board in which a conductor wiring and the second conductor wiring are electrically connected through a through hole, wherein the insulating substrate has a recessed portion provided with the through hole. The insulating substrate, the wiring board according to claim 1, wherein said first main surface side is depressed. The insulating substrate, the wiring board according to claim 1, wherein said first main surface side and the second main surface side is characterized in that it depressed. A glass substrate impregnated with any one of an epoxy resin, an imide resin, a BT resin, and a PPE resin on a glass cloth, or a sheet formed by intertwining short fiber glass yarns was impregnated with an epoxy resin. Forming a first thin film conductor on a first main surface of an insulating substrate made of a glass nonwoven fabric, and forming a second thin film conductor on a second main surface opposite to the first main surface of the insulating substrate; A step of recessing a predetermined position of the insulating substrate on which the first thin film conductor and the second thin film conductor are formed, a step of opening the recessed region of the insulating substrate, and through-hole plating on the opening of the insulating substrate And forming a first conductor wiring by patterning the first thin film conductor and patterning the second thin film conductor to form a second conductor wiring. Method of manufacturing a wiring board. A glass substrate impregnated with any one of an epoxy resin, an imide resin, a BT resin, and a PPE resin on a glass cloth, or a sheet formed by intertwining short fiber glass yarns was impregnated with an epoxy resin. A step of forming a first thin film conductor on one main surface of an insulating substrate made of a glass nonwoven fabric, a step of sinking a predetermined position of the insulating substrate on which the first thin film conductor is formed, and a region in which the insulating substrate is depressed A step of forming a second thin film conductor on a main surface of the insulating substrate opposite to a main surface on which the first thin film conductor is formed, and forming a through-hole plating in the opening of the insulating substrate. A wiring comprising: a step; patterning the first thin film conductor to form a first conductor wiring; and patterning the second thin film conductor to form a second conductor wiring. Method of manufacturing the plate. The step of sinking a predetermined position of the insulating substrate on which the first thin film conductor and the second thin film conductor are formed includes pressing a columnar pressing jig from the first main surface side of the insulating substrate to sink. The method for manufacturing a wiring board according to claim 4, wherein: The step of recessing a predetermined position of the insulating substrate on which the first thin film conductor and the second thin film conductor are formed includes a columnar pushing jig from each of the first main surface side and the second main surface side of the insulating substrate. The method of manufacturing a wiring board according to claim 4 , wherein the wiring board is depressed by pressing. 6. The method of manufacturing a wiring board according to claim 5, wherein the step of sinking a predetermined position of the insulating substrate on which the first thin film conductor is formed presses a columnar pressing jig to cause the recess to be depressed. The insulating substrate is overheated and softened to a predetermined temperature, method of manufacturing a wiring board according to any one of claims 6 to 8, characterized in that to depressed by pressing the push jig. The use of a semi-cured resin material as an insulating substrate, after recessed a predetermined position of the insulating substrate, to any one of claims 6 to 8, characterized in that to fully cure the resin material The manufacturing method of the wiring board as described.

Images