JP2000151099A - Wiring board having three-layer integrated structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-reliable wiring board having a three layer integrated structure. SOLUTION: This wiring board has a three-layer integrate structure in which a built-up layer B1, which comprises insulation layers I1, I2 and conductive layers (C1, C2)are laminated alternately, are bonded in the state where they are interposed between rigid core boards 3, 4. An upper side core board 4 on the surface layer side of the built-up layer B1 is provided with a plurality of socket-like construction parts 24, 24A. Every construction parts 24, 24A are interconnected with the conductive layer (C1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-layer integrated wiring board.

[0002]

2. Description of the Related Art Conventionally, various types of wiring boards have been proposed. One example is a signal conversion module used by a personal computer user to upgrade a CPU.

[0003] This type of conversion module generally has two components.
The main component is a rigid substrate. A plurality of plated through holes and various conductor patterns are provided on the conversion board, which is the lower core board. The base end of an external connection pin is fixed to the opening on the lower surface side of each plating through hole. Each external connection pin is inserted into and extracted from each pin insertion hole of the PGA socket on the motherboard. The socket substrate, which is the upper core substrate, has a structure in which socket pins are respectively held in a plurality of pin holding holes provided in an insulating base material. The tip of each socket pin protrudes from the lower surface of the socket substrate, and is inserted into the upper opening of each plated through hole and soldered. An insertion hole is formed in the upper end surface of each socket pin, and an I / O pin of PGA, which is a CPU, can be fitted thereinto.

[0004] Therefore, it is considered that if a high-performance PGA is mounted using such a conversion module, the PGA can be adapted to the motherboard, and the original performance is easily exhibited.

[0005] In recent years, in order to achieve a greater upgrade, it has been required to mount an element such as a semiconductor package and thereby perform signal conversion. When such a structure is employed, it becomes necessary to perform a replacement connection for a specific socket pin.

As means for realizing the replacement connection, the present inventors have proposed the following in an already filed application. That is, by forming the build-up layer on the upper surface side of the conversion substrate and using the conductor layer in the same layer as a part of the connection path including the element, the replacement connection is not realized. At this time, each socket pin on the socket board side is surface-mounted on each conductor pattern on the surface layer of the build-up layer. Therefore, such a conversion module is a wiring board having a so-called three-layer structure including the conversion board, the socket board, and the build-up layer.

[0007]

However, although the above-mentioned conversion module is a three-layer wiring board, structurally, there is a slight gap between the lower surface of the socket substrate and the upper surface of the build-up layer. Are formed. Generally, the build-up layer is considered to be more fragile and more susceptible to moisture and the like than a rigid substrate.

[0008] Therefore, if the externally exposed portion of the build-up layer is large as described above, there is a possibility of causing damage or absorbing moisture, and it is expected that it is difficult to ensure high reliability in the conversion module itself.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a highly reliable wiring board having a three-layer integrated structure.

[0010]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a build-up layer formed by alternately stacking insulating layers and conductor layers is provided between a rigid core substrate. The gist of the present invention is a three-layer integrated wiring board bonded in a sandwiched state.

According to a second aspect of the present invention, in the first aspect, the upper core substrate on the surface side of the build-up layer has a plurality of socket-like structures to which a plurality of terminals protruding from the lower surface of the device can be attached and detached. And each of the socket-like structure portions and the conductor layer of the build-up layer are interconnected.

According to a third aspect of the present invention, in the first or second aspect, the upper core substrate on the surface side of the build-up layer has a three-dimensional uneven structure on an upper surface thereof. Hereinafter, the “action” of the present invention will be described.

According to the first aspect of the invention, the electrical connection between the conductors of the pair of core substrates is established via the conductor layer of the build-up layer. The build-up layer is sandwiched between a pair of rigid core substrates, and in this state, is adhered to both core substrates without any gap. That is, as a result of the build-up layer being protected by the core substrate, the externally exposed portion of the build-up layer is reduced. For this reason, the situation where the build-up layer is damaged or moisture is absorbed is avoided. Therefore, high reliability is secured in the build-up layer, and thus high reliability is secured in the wiring board itself.

According to the second aspect of the present invention, when the device is mounted on the upper surface of the upper core substrate, each terminal protruding from the lower surface of the device can be mounted on each socket-like structure. In addition, since the conductor layer of the build-up layer and each socket-like structure are interconnected, the use of the conductor layer makes it possible to relatively easily perform replacement connection of signal lines and the like for specific terminals. It becomes possible. Therefore, a wiring board having a function as a signal conversion module can be obtained.

According to the third aspect of the present invention, by forming a three-dimensional uneven structure according to the purpose on the upper surface of the upper core substrate, for example, heat dissipation, component positioning, device mounting, etc. Can be improved, and higher added value of the wiring board can be achieved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A PGA conversion module 1 of a first embodiment embodying a three-layer integrated wiring board of the present invention and a method of manufacturing the same will now be described with reference to FIGS. 3 will be described in detail.

As shown in FIGS. 1 and 2, the conversion module 1 of this embodiment is a device for mounting a PGA 2 which is a kind of chip module on a motherboard MB after performing a predetermined signal conversion. is there. On the lower surface of the PGA 2 as a device, I / O pins 26 as a plurality of terminals are regularly projected.

The conversion board 3 as a lower core board constituting the conversion module 1 is rigid and has a rectangular shape. The conversion board 3 is a so-called double-sided board having conductors on both front and back surfaces of an insulating base material. The conversion board 3 includes a plated through-hole group in which a large number (several hundreds in the present embodiment) of plated-through holes 5 are arranged in a substantially rectangular shape. The plating through holes 5 are arranged in a grid pattern or a staggered pattern at a constant pitch.

One of the plurality of plated through holes 5 (shown by 5A) is formed at a position corresponding to one of a plurality of socket pins 24 to be described later that needs to be replaced (shown by 24A). Have been.

The base end of the external connection pin 6 is press-fitted (press-fitted) without soldering into the lower opening of each of the plated through holes 5 and 5A.
As a result, conduction between each external connection pin 6 and each plating through hole 5, 5A is achieved.

On the lower surface side of the conversion board 3, sub-boards 32 are arranged at a predetermined interval. Pin 6 for each external connection
Is inserted through the pin insertion hole 36 of the sub-substrate 32 so that it cannot be pulled out, and its tip protrudes from the lower surface of the sub-substrate 32 by a predetermined length. Since the external connection pins 6 are fixed to each other, the bending of the pins is prevented, so that it is hard to hinder the insertion and removal of the pins 6.

As shown in FIG. 1 and FIG.
A build-up layer B1 is formed on the entire upper surface of the substrate. The build-up layer B1 is manufactured through a build-up process, and refers to a layer obtained by alternately laminating insulating layers and conductor layers. More specifically, in the conversion module 1 of the present embodiment, the build-up layer B1 composed of two insulating layers I1 and I2 and two conductive layers C1 and C2.
Are formed.

On the upper surface of the insulating layer I1 on the inner layer side, an inner conductor layer C1 (specifically, the conductor pattern 15) is formed. The inner conductor layer C1 and the land 5a on the upper surface of the conversion substrate 3 are connected to the via hole 18 formed in the insulating layer I1.
Are electrically connected to each other. On the upper surface of the insulating layer I2 on the outer layer side, an outer conductor layer C2 (specifically, various pads 7, 8, 8a, 8b, 14 and the conductor pattern 1) are formed.
6) is formed. Outer conductor layer C2 and inner conductor layer C
1 are electrically connected to each other through via holes 19 formed in the insulating layer I2.

The upper surface of the build-up layer B1 (ie, the insulating layer I)
2 upper surface), one die pad 7 is provided in a substantially square region surrounded by the plated through hole group.
A plurality of bonding pads 8 surrounding it are formed. On the die pad 7, a QFP (quad flat package) 9 for signal conversion as an element for performing signal conversion is surface-mounted. Each lead of the QFP 9 is joined to each pad 8 using solder S1 which is a conductive material. One of the plurality of pads 8 is assigned as an input pad 8a for replacement connection, and another one is assigned as an output pad 8b for replacement connection.

The input side pad 8a is connected to the secondary side end of the conductor pattern 16 formed on the upper surface of the insulating layer I2. The output-side pad 8b is connected to the conductor pattern 15 on the inner layer.
Are connected to each other through a via hole 19 with respect to the primary side end. Further, the secondary side end of the conductor pattern 15 is connected via a via hole 18 to the upper surface side land 5Aa of the specific plated through hole 5A that requires replacement connection.

In the plated through hole 5 which does not require the replacement connection, the via holes 18 and 19 are arranged so as to be arranged substantially in series along the axial direction of the plated through hole 5. As a result, conduction between the upper surface side land 5a and the connection pad 14 located immediately above the land 5a is achieved.

As shown in FIG. 1, a pad 10 for connecting electronic components is formed in a region on the upper surface of the conversion substrate 3 which is not surrounded by the through-hole group. A DIP (dual in-line package) 11 is surface-mounted on the pad 10. An electronic component connection pad 12 is also formed on the lower surface side of the conversion board 3, and a chip resistor 13 is surface-mounted thereon. These electronic components 11 and 13 are also joined to the pads 10 and 12 using solder S1.

However, some other conductor patterns (not shown) are formed on the lower surface side of the conversion board 3. The conductor pattern electrically connects the land 5b of the plated through hole 5 and the pad 12 for the electronic component 13 to each other. A conductor pattern (not shown) for electrically connecting the pads 8 and 10 is also formed on the upper surface of the insulating layer I2 on the outer layer side.

As shown in FIGS. 1 and 2, the socket substrate 4 as the upper core substrate has a rigid, insulating base member 21 having a square outer shape as a constituent element. The insulating base 21 has a square central hole 22. Around the central hole 22, a number of pin holding holes 23 having a circular cross section and a diameter much smaller than the central hole 22 are formed. In each pin holding hole 23, each socket pin 24, 24A as a socket-like structure is inserted and held so as not to come out. The socket pins 24 and 24A of this embodiment are for PGA, and the number is about several hundreds. Each socket pin 24, 24A is formed with an insertion hole 25 extending along the axial direction. The insertion hole 25 is opened at the center of the upper end surface of the socket pins 24 and 24A, and the I / O pin 26 of the PGA 2 can be inserted and removed therefrom. That is, the socket substrate 4
Has a structure on the upper surface side where the PGA 2 can be attached and detached. An engagement protrusion (not shown) for securely holding the I / O pin 26 may be provided on the inner wall surface of the insertion hole 25 so as to face the same. In the present embodiment, the lower end surfaces of the socket pins 24 and 24A slightly protrude from the lower surface side of the insulating base material 21.

The surface side of the build-up layer B1 and the lower surface of the socket substrate 4 are entirely bonded by an adhesive layer 51 made of an insulating resin material. That is, the conversion module 1 of the present embodiment has a structure (three-layer integrated structure) in which the conversion board 3, the build-up layer B1, and the socket board 4 are integrated. It can also be understood that the build-up layer B1 is adhered while being sandwiched between a pair of rigid substrates 3 and 4. Also, build-up layer B
There is no gap at the bonding interface between 1 and the socket substrate 4. In the present embodiment, such an adhesive layer 51 is formed using an epoxy resin-based adhesive sheet. The thickness of the adhesive layer 51 is set to several hundred μm to several mm.

As shown in FIG. 2, a concave portion 52 is provided at a position corresponding to the primary side end 16a of the conductor pattern 16 and the pad 14 in the adhesive layer 51. Recess 52
Has a circular cross section, and is formed one size larger than the pin holding hole 23.

A plating layer 53 is formed on the surface of the conductor layer C 2 (that is, the primary end 16 a and the pad 14), the inner wall surface of the pin holding hole 23, and the inner wall surface of the recess 52.
The plating layer 53 is also in contact with the lower end surface and the entire outer peripheral surface of each socket pin 24, 24A. Therefore, each socket pin 24 and each pad 14 are connected via the conductive plating layer 53, and as a result, both
24 are in a state of being electrically connected. Similarly,
Socket pin 24A and primary end 1 via plating layer 53
As a result, the connection between the two 16a and 24A is reliably conducted. That is, in the conversion module 1, the build-up layer B1 and the socket substrate 4
An interlayer connection layer 5 made of a plating layer 53
4 can be grasped. In the present embodiment, the plating layer 53 also has a role of holding the socket pins 24 and 24A in the pin holding holes 23 so as not to come out.

The socket pins 24 that do not require replacement connection are:
It is electrically connected to the plated through hole 5 via a simple connection path composed of two via holes 18 and 19. On the other hand, the specific socket pin 24A is electrically connected to the plated through hole 5A via a connection path that is slightly more complicated than the socket pin 24 described above.

The latter connection path is, so to speak, a specific socket pin 24A and a corresponding plated through hole 5A.
Can be grasped as a connection path for conducting through the QFP 9. The conductor layers C1 and C2 in the build-up layer B1 are used as a part of the connection path.

Next, the structure of the PGA socket 41 will be described. The PGA socket 41 includes a socket body 42 including a fixed member and a movable member. A plurality of pins 43 are protrudingly provided on the lower surface side of the fixing member constituting the socket body 42. These pins 43 are soldered to plated through holes on the motherboard MB side.

A movable member is disposed on the upper surface of the fixed member so as to cover the movable member. The movable member has a plurality of pin insertion / extraction holes 44 through which the socket pins 24 and 24A can be inserted / extracted. These pin insertion / extraction holes 44 have a positional relationship corresponding to the socket pins 24 and 24A.

A step 46 having a predetermined height exists on the upper surface side of the movable member. An operation lever 45 as an operation means is provided in a through hole passing through the step portion 46 in the horizontal direction by about 90 degrees.
It is inserted so that it can rotate about °. This operation lever 45
Moves between a locked position and an unlocked position. When the operation lever 45 is rotated, the movable member slides slightly along the horizontal direction. Socket pins 24, 24
A is inserted into each pin insertion / extraction hole 44 with the operation lever 45 rotated to the unlock position. Operation lever 45
Is rotated to the lock position, the pin insertion / extraction holes 44 are narrowed, and the socket pins 24 and 24A are
1 is fixed so that it cannot escape. At this time, the contacts in each pin insertion hole 44 are connected to each socket pin 24, 24.
As a result, electrical continuity with the motherboard MB is achieved.

In this embodiment, the socket 41 for PGA is "Socket" manufactured by Thomas & Bets Company.
5 "or" Socket 7 "(both ZIF series).

Next, an example of a method of manufacturing the conversion module 1 of the present embodiment having a three-layer integrated structure will be described with reference to FIG. First, the conversion substrate 3 is prepared in advance. The conversion substrate 3 can be obtained by forming a conventionally known pattern such as a subtractive method using, as a starting material, a material obtained by attaching copper foil to both surfaces of an insulating substrate made of glass epoxy, for example. Thereby, plated through holes 5 and 5A and pads 10 and 12 are formed, and a desired conversion substrate 3 is manufactured.

In a subsequent build-up layer forming step, a build-up layer B 1 is formed on the upper surface of the conversion substrate 3 by a build-up process. Here, first, a photosensitive epoxy-based additive adhesive is applied to the upper surface of the conversion substrate 3.
The photosensitive epoxy-based additive adhesive refers to a resin matrix in which a resin filler relatively soluble in an oxidizing agent is dispersed in a resin matrix relatively insoluble in an oxidizing agent. Next, by performing exposure and development, an insulating layer I1 having a via hole forming hole having an inner diameter of about several tens of micrometers is formed. Next, using chromic acid as a roughening agent (oxidizing agent),
A chemical roughening process is performed on the insulating layer I1. afterwards,
A catalyst nucleus is provided, a permanent resist (not shown) is formed, plating pretreatment, and electroless copper pattern plating are performed. After the above-described plating process, a copper plating layer is deposited on a portion where a permanent resist is not formed or on an inner wall surface of a via hole forming hole. Therefore, the conductor pattern 15 and the via hole 18 are formed in the insulating layer I1. Via hole 18 thus formed
Is a so-called filled via in which the inside of the via hole forming hole is completely filled with a copper plating layer.

Further, the same procedure is applied to the upper surface of the insulating layer I1 in which the via hole 18 is formed, in accordance with the same procedure as described above, application of an adhesive layer, exposure and development, roughening treatment, catalyst nucleation, formation of a permanent resist, Perform processing and electroless copper pattern plating. As a result, pads 7, 8, 8 are formed on insulating layer I2.
a, 8b, 14, conductor pattern 16, via hole 19
Is formed, and a desired build-up layer B shown in FIG.
1 is completed.

Next, on the surface of the build-up layer B1, an adhesive sheet serving as the adhesive layer 51 is positioned and arranged. At a predetermined position of the adhesive sheet, a circular opening serving as the concave portion 52 is provided in advance. Further, a perforated insulating base material 21 which will later become the socket substrate 4 is positioned on the adhesive sheet and then superposed. At this time, the pin holding hole 23 is already formed at a predetermined position of the insulating base material 21. Then, by applying a pressing force in the thickness direction of the substrate while heating, the build-up layer B1 and the insulating base material 21 are integrally bonded via the bonding layer 51 (see FIG. 3B). In other words, the conversion substrate 3 and the insulating base material 21 are indirectly bonded via the adhesive layer 51 and the build-up layer B1.

Next, after a plating resist is formed on the upper surface of the insulating base material 21, a catalyst nucleus is applied and activated, and then electroless plating is performed. In this case, the lower surface side of the conversion substrate 3 which does not need to deposit copper plating is preferably entirely protected by, for example, coating a plating resist (not shown). Then, as shown in FIG. 3C, a plating layer 53 is formed on the primary end 16a, the surface of the pad 14, the inner wall surface of the pin holding hole 23, and the inner wall surface of the concave portion 52. Specifically, in the present embodiment, an electroless copper plating layer is formed. In order to secure the plating thickness, the electroless copper plating layer may be used as a base to further perform the plating by electrolytic copper plating. The unnecessary plating resist is removed at this point.

Further, each of the socket pins 24, 24A is press-fitted from an opening on the upper surface side of each of the pin holding holes 23, so that each of the socket pins 24, 24A is inserted into each of the pin holding holes 23.
(See FIG. 3 (d)). That is, the socket board 4 is completed at this point.

After the above substrate bonding step and socket pin mounting step, a pin press-in and fixing step is subsequently performed. Then, each plated through hole 5, 5
A, the base end of the external connection pin 6 is press-fitted from the lower surface side opening and fixed. Further, by printing solder cream on various pads 7, 8, 8a, 8b, 10, 12 and temporarily fixing and reflowing parts, QF
P9 and the electronic components 11 and 13 are soldered to predetermined locations. Instead of printing the solder cream, soldering may be performed individually for each component.

Next, the desired conversion module 1 is completed by inserting the external connection pins 6 into the pin insertion holes 36 of the sub-board 32 and fixing them so that they cannot be pulled out. The PGA 2 is added to the conversion module 1 thus configured.
Is mounted, and further mounted on the PGA socket 41 of the motherboard MB, the result is as follows.

PGA flowing through a specific socket pin 24A
The signal No. 2 is input to the QFP 9 via a route of the interlayer connection layer 54 → the conductor pattern 16 → the input side pad 8a. The converted signal is output from the QFP 9 and then reaches the upper surface land 5Aa of the plated through hole 5A via a route of the output pad 8b → the via hole 19 → the conductor pattern 15 → the via hole 18. The converted signal reaching the land 5Aa is a plated through hole 5
The copper is supplied to the motherboard MB through a route of the copper plating layer in A → the lower surface side land 5Ab → the external connection pin 6 → the pin 43 of the PGA socket 41. As a result of the exchange connection using the conductor layers C1 and C2 of the build-up layer B1, signal conversion is mainly performed by the QFP 9, and the original function of the PGA 2 is sufficiently exhibited.

Therefore, according to the present embodiment, the following effects can be obtained. (1) In the conversion module 1 having the three-layer integrated structure,
The build-up layer B1 is sandwiched between the rigid conversion board 3 and the socket board 4, and in this state, both boards 3, 4
Are adhered to each other without any gap. As a result of the protection of the build-up layer B1 by the two substrates 3 and 4, the externally exposed portion of the build-up layer B1 is reduced. For this reason, unlike the case where there is a large externally exposed portion due to the presence of the gap, the build-up layer B
The damage of 1 and the absorption of moisture are avoided beforehand,
Inconveniences such as a decrease in insulation are less likely to occur. In addition, mechanical stress is less likely to be applied to the build-up layer B1 sandwiched between the rigid substrates 3 and 4, thereby preventing cracks and the like. Therefore, build-up layer B
1 ensures high reliability and, consequently, the conversion module 1
High reliability itself can be secured.

(2) The conversion module 1 of the present embodiment
It has a number of socket pins 24, 24A. Also,
Each of the socket pins 24, 24A and the conductor layer C2 (primary end 16a and pad 14) of the build-up layer B1 are interconnected. Therefore, the PGA is
2 is mounted, each I / O pin 26 can be mounted on each socket pin 24, 24A.

The conductor layers C 1,
By using C2, a specific socket pin 24A
As a result, it is possible to obtain a wiring board capable of relatively easily performing replacement connection of signal lines, that is, a wiring board having a function as a signal conversion module.

(3) The method of manufacturing the conversion module 1 of the present embodiment does not employ a method of purchasing a commercially available socket board and using it as it is. Therefore, the material cost can be reduced as compared with the case where expensive commercial products are purchased, and the cost of the entire conversion module 1 can be prevented. [Second Embodiment] Next, a method of manufacturing a PGA conversion module 1 according to a second embodiment of the present invention will be described with reference to FIG. Here, the differences from the first embodiment will be mainly described, and the common points will be denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, first, a build-up layer forming step is performed according to the above-described procedure to form a build-up layer B1 on the upper surface of the core substrate 17 (see FIG. 4A). Next, the adhesive layer 51 and the socket substrate 4 are arranged on the surface of the build-up layer B1 so as to be superposed in that order. In the present embodiment, an insulating base material 21A in which the pin holding holes 23 are already formed and the copper plating layer 61 is formed on the inner peripheral surface and the opening thereof is used. That is, the insulating base material 21A has a structure similar to the plated through hole at a plurality of locations. The surface layer of the copper plating layer 61 may be subjected to solder plating. Then, by applying a pressing force in the thickness direction of the substrate while heating, the build-up layer B1 and the insulating base material 21 are integrally bonded via the bonding layer 51 (see FIG. 4B).

Subsequently, a substantially spherical solder particle 62, which is a conductive metal particle, is inserted into each of the pin holding holes 23 using a special particle inserting device, and then each of the socket pins 24, 24A is inserted.
Is inserted into each pin holding hole 23 (see FIG. 4C). The average particle size of the solder particles 62 is preferably slightly smaller than the inner diameter of the pin holding hole 23. The solder particles 62 may be inserted one by one for each hole, or a plurality of solder particles may be inserted as needed.

Further, the solder particles 62 are formed using a reflow furnace.
Is heated and melted and solidified to form an interlayer connection layer 63.
Is formed, and at this point, the socket substrate 4 is completed (see FIG. 4D). Then, through this interlayer connection layer 63,
The lower end surface of each socket pin 24 is connected to each pad 14, and the lower end surface of socket pin 24A is connected to conductor pattern 1.
6 is connected to the primary end 16a.

After the above-described substrate bonding step and socket pin mounting step, a pin press-in and fixing step is subsequently performed. Then, each plated through hole 5, 5
A, the base end of the external connection pin 6 is press-fitted from the lower surface side opening and fixed. Further, by printing solder cream on various pads 7, 8, 8a, 8b, 10, 12 and temporarily fixing and reflowing parts, QF
P9 and the electronic components 11 and 13 are soldered to predetermined locations. Instead of printing the solder cream, soldering may be performed individually for each component. It should be noted that the component soldering step can be performed before the pin press-fitting step or the socket pin mounting step.

Therefore, even in the present embodiment, the effects (1), (2), and (3) listed in the first embodiment can be obtained. Third Embodiment Next, a method of manufacturing a PGA conversion module 1 according to a third embodiment of the present invention will be described with reference to FIG. Here, the differences from the first embodiment will be mainly described, and the common points will be denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, first, a build-up layer forming step is performed according to the above-described procedure to form a build-up layer B1 on the upper surface of the core substrate 17 (see FIG. 5A). Next, an adhesive sheet to be the adhesive layer 51 is positioned and pressed on the surface of the build-up layer B1. At a predetermined position of the adhesive sheet, a circular opening serving as the concave portion 52 is provided in advance (see FIG. 5B).

Further, the solder paste 7 as a conductive metal paste is
1 is printed with a predetermined thickness (see FIG. 5C). As the solder paste 71, for example, eutectic solder (Pb: Sn = 3)
7:63, melting point 183 ° C.) dispersed in a vehicle. The surface of the solder paste 71 is coated with a flux according to a conventionally known method.

After the paste printing step, the socket substrate 4 is positioned on the adhesive sheet and then superposed. In the present embodiment, a commercially available socket substrate 4 in which the socket pins 24 and 24A are already molded in the respective pin holding holes 23 of the insulating base 21B is used as it is. And
By applying a pressing force in the thickness direction of the substrate while heating, the build-up layer B1 and the insulating base material 21B are integrally bonded via the bonding layer 51. Further, the solder paste 71 is heated and melted using a reflow furnace and solidified, thereby forming the interlayer connection layer 72 (see FIG. 5D). The lower end surface of each socket pin 24 and each pad 14 are connected via the interlayer connection layer 72, and the lower end surface of the socket pin 24 A and the primary end 16 a of the conductor pattern 16 are connected. Thereafter, if a pin press-in fixing step and a component soldering step are performed, a desired conversion module 1 having a three-layer integrated structure is completed.

Therefore, even in this embodiment, the effects (1) and (2) listed in the first embodiment can be obtained. [Fourth Embodiment] Next, a method of manufacturing a PGA conversion module 1 according to a fourth embodiment of the present invention will be described with reference to FIG. Here, the differences from the third embodiment will be mainly described, and the common points will be denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, first, after the build-up layer forming step is performed, the adhesive sheet serving as the adhesive layer 51 is pressure-bonded (see FIGS. 6A and 6B). Here, instead of printing the solder paste 71 in the concave portion 52, an anisotropic conductive elastic material 81 as an anisotropic conductive material is disposed there (FIG. 6).
(c)). Specifically, in the present embodiment, a somewhat flat spherical anisotropic conductive rubber is used. As the anisotropic conductive rubber, one having a size that can be arranged in the concave portion 52 is selected. In the rubber matrix constituting the anisotropic conductive rubber, conductive metal particles are uniformly dispersed. Accordingly, when the rubber is elastically deformed by applying a pressing force in a predetermined direction, the rubber is compressed and the conductive metal particles are short-circuited, so that a conductive state along the pressing force applying direction is obtained.

After the conductor arranging step, a commercially available socket substrate 4 is positioned on the adhesive sheet and then superposed. By applying a pressing force in the thickness direction of the substrate while heating, the build-up layer B1
And the insulating base material 21B are integrally bonded. At this time, the anisotropic conductive rubber 81 is compressed by the lower end surfaces of the socket pins 24 and 24A in the thickness direction of the substrate and is somewhat crushed (see FIG. 6D). As a result, the lower end face of each socket pin 24 is connected to each pad 14 via the interlayer connection layer 82, and the lower end face of the socket pin 24A is connected to the primary side end 16a of the conductor pattern 16. Thereafter, if a pin press-in fixing step and a component soldering step are performed, a desired conversion module 1 having a three-layer integrated structure is completed.

Therefore, according to this embodiment, the same effects as those of the third embodiment (that is, the effects enumerated in the first embodiment) can be obtained.
(1) and (2)) can be obtained. Fifth Embodiment Next, a method of manufacturing a PGA conversion module 1 according to a fifth embodiment of the present invention will be described with reference to FIG. Here, the differences from the first embodiment will be mainly described, and the common points will be denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, first, a build-up layer forming step is performed according to the above-described procedure to form a build-up layer B 1 on the upper surface of the core substrate 17 (see FIG. 7A). Next, the adhesive layer 51 and the insulating base material 21C are arranged on the surface of the build-up layer B1 so as to be overlapped in that order. In the present embodiment, an insulating base 21C in which the pin holding holes 23 are not formed is used. By applying a pressing force in the thickness direction of the substrate while heating, the adhesive layer 51 is formed.
Then, the build-up layer B1 and the insulating base material 21C are integrally adhered to each other (see FIG. 7B).

Next, a laser beam is radiated vertically from the upper surface side of the insulating base material 21C using a laser irradiator to form a laser processing hole H1 in a predetermined area (see FIG. 7 (c)). At that time, it is necessary to irradiate the primary side end 16a or the area where the pad 14 is located, that is, the area where the metal is located. The upper portion of the laser-processed hole H1 thus processed becomes the pin holding hole 23 in the insulating base material 21C, and the lower portion becomes the concave portion 52 in the adhesive layer 51. Because of laser processing, pin holding hole 2
3 and the recess 52 have substantially the same size and the same cross-sectional shape.

Thereafter, if the socket pin mounting step, the pin press-in fixing step, and the component soldering step are performed in accordance with the method of Embodiment 1, the desired conversion module 1 having a three-layer integrated structure is completed.

Therefore, even in the present embodiment, the first
The effects (1), (2), and (3) listed in the embodiment can be obtained. [Sixth Embodiment] Next, a conversion module 91 according to a fifth embodiment of the present invention will be described with reference to FIGS. Here, the differences from the first embodiment will be mainly described, and the common points will be denoted by the same reference numerals, and description thereof will be omitted.

Another conversion module 91 shown in FIG.
Are configured to mount a BGA (bump grid array) 92 which is a kind of chip module. A large number of substantially hemispherical bumps 93 as terminals protrude from the lower surface of the BGA 92. Instead of such bumps 93, a structure in which a sphere-shaped ball or the like is protruded may be used.

As shown in FIG. 9, the socket substrate 4 as the upper core substrate in this embodiment has a three-dimensional uneven structure on the upper surface. More specifically,
At each corner on the upper surface side of the insulating base material 21D constituting the socket substrate 4, a projecting piece 98 for preventing displacement is vertically provided in the thickness direction of the substrate.
Each of these four protruding pieces 98 is integrally formed with the insulating base material 21D. BGA 9 arranged between each projection 98
In No. 2, the displacement in the horizontal direction of the substrate is restricted by each protruding piece 98, and as a result, displacement is less likely to occur.

A cover 99 is placed over the insulating base 21D. Locking claws 102 as locking portions are formed at a plurality of locations on the lower edge of the lid 99. These locking claws 102 can be engaged with and disengaged from the outer peripheral lower edge of the insulating base 21D. That is, each locking claw 102 functions as a stopper when the lid 99 is attached. A coin screw 100 as a device pressing member is screwed into a female screw hole 101 penetrating through the center of the lid 99. Then, by rotating the coin screw 100 and moving it downward, the BGA 92 is pressed and fixed to the insulating base material 21D side.

As shown in FIG. 9, the socket board 4 of this embodiment has a large number of BGA socket pins 94. The BGA socket pin 94 has a structure in which a lower half 95 and an upper half 96 are connected by a spring 97. The lower half 95, the upper half 96, and the spring 97 are all made of a conductive metal material. The lower half 95 is held in the opening on the lower surface side of the pin holding hole 23 so as not to come out.
The upper half 96 is accommodated in the pin holding hole 23 so as to be slidable in the vertical direction. A hemispherical concave portion is formed on the upper end surface of the upper half portion 96, and the bottom surface of the bump 93 is pressed against the concave portion. It should be noted that a specific BGA socket pin requiring replacement connection is provided with 94A for convenience of explanation. In the present embodiment, each socket pin 9 is also interposed via the interlayer connection layer 54.
4 is connected to the primary end 16a and the socket pin 9
4A and the pad 14 are connected.

The conversion module 91 having a three-layer integrated structure can be manufactured basically by the procedure described in the first embodiment. Therefore, even in the present embodiment, (1) and (2) listed in the first embodiment.
The effect of (3) can be obtained.

In particular, since the conversion module 91 has an uneven structure on the upper surface of the socket board 4, the conversion module 91 has a structure advantageous for mounting the BGA 92. That is, 4
As a result, the displacement of the two projections 98 is less likely to occur,
The mounting of the device is improved, and consequently the conversion module 9
The added value of 1 itself increases. In this embodiment, the conversion module 91 having an uneven structure on the upper part is manufactured without using a commercially available socket substrate. If a similar product is to be manufactured using a commercially available socket substrate having a flat upper surface, the upper surface needs to be subjected to grinding or the like, which leads to an increase in cost. On the other hand, in the present embodiment, there is no necessity, and as a result, cost increase can be prevented. In addition, since the uneven structure is formed on the insulating base material 21D by integral molding, a complicated shape that is difficult to obtain only by grinding can be obtained relatively easily.

The embodiment of the present invention may be modified as follows. Instead of forming the adhesive layer 51 using the adhesive sheet in the above embodiments, for example, a liquid adhesive is applied to the build-up layer B1 or the insulating bases 21, 21A, 21B or the like to thereby form the adhesive layer 51. May be adopted.

A build-up layer B on the upper surface of the conversion substrate 3
1 is formed and then the socket substrate 4 is bonded to the lower surface of the socket substrate 4.
After forming, the conversion substrate 3 may be bonded.

A rigid substrate other than the conversion substrate 3 may be used as the lower core substrate. That is, the present invention provides conversion modules 1 and 9 as described in the above embodiments.
It can be embodied as a wiring board other than one.

The upper core substrate has socket pins 24,
24A, 94, and 94A may be provided with a socket-like structure having a different structure, or may be provided with no socket-like structure.

In the conversion module 91 of the sixth embodiment, a plurality of projections 98 are formed on the upper surface of the socket substrate 4 as the upper core substrate for the purpose of improving the mounting of the BGA 92. Of course, different three-dimensional uneven structures may be formed according to the purpose. Examples thereof include a radiation fin formed for the purpose of improving heat radiation, a component housing recess for improving the positioning of a surface-mounted component at the time of soldering, and the like. When such an uneven structure is provided on a wiring board having a three-layer integrated structure,
Thereby, the added value of the wiring board can be further increased.

Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments are listed below together with their effects. (1) The inner wall surface of the conductive layer, the inner wall surface of the holding hole penetrated through the upper core substrate, and the inner wall surface of the concave portion provided in the adhesive layer corresponding to the conductive layer according to claim 2. The socket-like structure and the conductor layer are connected via an interlayer connection layer formed of a plating layer formed on the substrate. Therefore, according to the invention described in the technical idea 1, it is possible to reliably conduct between the conductors of the two core substrates via the suitable interlayer connection layer, and to thereby ensure high reliability of the wiring board.

(2) The socket-like structure according to (2) or (3), via an interlayer connecting layer formed by melting and solidifying the conductive metal particles inserted into the holding holes provided through the upper core substrate. Section and the conductor layer are connected. Therefore, according to the invention described in the technical idea 2, the same effect as the invention of the technical idea 1 can be obtained.

(3) In the second and third aspects, a conductive metal paste printed in a recess provided in the adhesive layer corresponding to the conductor layer is melted and solidified through an interlayer connection layer. The socket-like structure and the conductor layer are connected. Therefore, according to the invention described in the technical idea 3, the same effect as the invention of the technical idea 1 can be obtained.

(4) The substrate according to (2) or (3), wherein an anisotropic conductor disposed in a recess provided in the adhesive layer corresponding to the conductor layer is provided on a lower end surface of the socket-like structure. Through the interlayer connection layer compressed in the thickness direction,
The socket-like structure and the conductor layer are connected. Therefore, according to the invention described in the technical idea 4, the same effect as the invention of the technical idea 1 can be obtained.

(5) In any one of claims 1 to 3 and technical ideas 1 to 4, the wiring board having the three-layer integrated structure performs signal conversion or the like of the device and then switches the device. A conversion module to be mounted on the PGA socket on the motherboard.

[0084]

As described in detail above, according to the first to third aspects of the present invention, it is possible to provide a highly reliable three-layer integrated wiring board.

According to the second aspect of the present invention, a wiring board having a function as a signal conversion module can be obtained. According to the third aspect of the invention, it is possible to increase the value of the wiring board.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a use state of a conversion module according to a first embodiment of the invention.

FIG. 2 is a partially enlarged cross-sectional view illustrating a use state of the conversion module according to the first embodiment.

FIGS. 3A to 3D are enlarged cross-sectional views of a main part for describing a manufacturing procedure of the conversion module according to the first embodiment.

FIGS. 4A to 4D are enlarged cross-sectional views of a main part for describing a manufacturing procedure of a conversion module according to a second embodiment.

FIGS. 5A to 5D are enlarged cross-sectional views of a main part for describing a manufacturing procedure of a conversion module according to a third embodiment.

FIGS. 6A to 6D are main-part enlarged cross-sectional views illustrating a manufacturing procedure of a conversion module according to a fourth embodiment.

FIGS. 7A to 7D are enlarged cross-sectional views of a main part for describing a manufacturing procedure of a conversion module according to a fifth embodiment.

FIG. 8 is a schematic side view showing a usage state of a conversion module according to a sixth embodiment.

FIG. 9 is a partially enlarged cross-sectional view illustrating a usage state of a conversion module according to a sixth embodiment.

[Explanation of symbols]

.., 1, 91... Three-layer integrated wiring board, 2... PGA as device, 3... (Lower) conversion board as core board,
4 (upper) socket board as core board, 24, 2
4A: socket pins (for PGA) as a socket-like structure; 26, pins as terminals; 92, BGA as devices; 93, bumps as terminals;
Socket pins (for BGA) as socket-like structure,
98: projecting piece as an uneven structure, I1, I2: insulating layer, C
1, C2: Conductive layer, B1: Build-up layer.

Claims (3)

[Claims] 1. A wiring board having a three-layer integrated structure in which a build-up layer formed by alternately laminating insulating layers and conductor layers is adhered while being sandwiched between rigid core substrates. 2. An upper core substrate on a surface layer side of the build-up layer includes a plurality of socket-like structure portions to which a plurality of terminals protruding from a lower surface of the device are detachably attachable. The three-layer integrated wiring board according to claim 1, wherein the conductive layer of the build-up layer is interlayer-connected. 3. The three-layer integrated wiring board according to claim 1, wherein the upper core substrate on the surface layer side of the build-up layer has a three-dimensional uneven structure on an upper surface thereof.