JPH10284632A - Circuit substrate and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the mounting operation of a circuit part, even when the substrate material and the circuit part having ordinary heat-resistant property are used, to mount a chip and an inserting type part on the same substrate, and to accomplish high density in the manufacture of the circuit substrate on which a circuit part is mounted and it is connected by a multilayered wiring. SOLUTION: A plurality of wirings are laminated between wirings pinching an interlayer insulating film on a part of a circuit substrate in the circuit substrate, a multilayered wiring part 111, on which the upper and the lower wirings are connected through the inner via hole of the interlayer insulating film formed on the lower wiring is provided, and the part which is the mounted surface of the circuit substrate 112, including the surface of the multilayered wiring part 111, is almost planarized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board and a method of manufacturing the same, and more particularly, to a circuit board on which circuit parts are mounted and the circuit parts are connected to each other by multilayer wiring, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in order to reduce the size and speed of electronic devices, there is a demand for higher integration of semiconductor integrated circuit devices and higher density of mounting substrates. For this reason, the wiring in the circuit board has been miniaturized, and a multilayer printed board having a plurality of wirings formed in layers from a single-layer printed board has been used. At present, a printed circuit board in which several tens of layers of multilayer wiring are built has been put to practical use. Then, wirings of different layers are connected through through holes penetrating the printed circuit board. Most electronic components are mounted on such a printed circuit board.

[0003] The printed circuit board is prepared as follows. That is, as shown in FIG.
A plurality of epoxy resin plates 1a-1e on which 2d and electrodes 2e, 2f are formed are semi-cured epoxy resin sheets 3a-3
Layer through d. Subsequently, as shown in FIG.
The substrate 101 is formed by hot pressing and integrating. After that, the substrate 10 is connected to a place where the interlayer wirings 2a to 2d are connected.
1 through holes 4a to 4d are formed.

Then, as shown in FIG. 7C, copper films 5a to 5d are formed on the inner wall surfaces of the through holes 4a to 4d to connect the desired wirings 2a to 2d between the layers. However, in the case of such a printed circuit board 101, only one set of wirings 3b and 3d can be connected with one through hole 4a, and it is necessary to perform wiring avoiding the through holes 4a to 4d in all layers. For this reason, there is a limit to high density. On the other hand, with the increase in the number of terminals and the narrower pitch of the semiconductor integrated circuit device, there is an increasing demand for high-density wiring which is difficult to cope with the printed circuit board of the above-described embodiment.

[0005] In order to realize higher density,
Wiring connection between layers by an inner via hole (interlayer connection hole) is required. As shown in FIG. 8, for a multi-chip module (MCM) in which a plurality of multi-terminal, narrow-pitch LSI chips are mounted, a plurality of wirings 12a to 12d are layered by a thin-film multilayer method or a built-up method.
Is formed at a high density, and wirings 12a to 12d of different layers are connected by inner via holes 14a to 14c formed in interlayer insulating films 13a to 13c.

[0006] Such multilayer circuit boards 102 are classified into the following types according to the material of the underlying substrate.
That is, MCM-D using a ceramic substrate, MCM-C using a Si substrate, MCM-L using a resin substrate, and the like (Journal of the Circuit Packaging Society, vol.11 No.5 1996, pp.311-315). reference). When mounting a multi-terminal, narrow-pitch LSI chip, for example, a ball grid array (BGA) type chip size package (CSP) or a bare chip having area bumps on a printed circuit board (mother board) 101 containing the above-described multilayer wiring, As shown in FIG. 9, after once mounting an LSI chip on a multilayer circuit board by soldering to form an MCM unit 103,
Is mounted on the printed circuit board 101 by soldering. In this case, MC
A board-to-board connection hole penetrating the board 11 is formed in the board 11 of the M unit 103, and the MC connection hole is formed through the board-to-board connection hole.
The wiring in the M unit 103 and the wiring in the printed circuit board 101 are connected. Note that in FIG.
Reference numeral 4 denotes an insertion type component, and reference numeral 105 denotes a chip resistor or chip capacitor.

[0007]

However, it is extremely expensive to make the entire circuit board a multilayer circuit board 102 having such inner via holes 14a to 14c. For this reason, a semiconductor chip having high-density wiring is once assembled as an MCM, and then mounted on a normal glass epoxy board together with components having relatively low-density wiring.

[0008] Such a method has a problem that the number of steps is increased. Further, when mounting the MCM unit 103 and other components (such as a chip resistor and a QFP) on the printed circuit board 101, the MCM unit soldered first is used. 103
Care must be taken to keep the side solder joints from coming off. For this reason, even if the solder on the MCM unit 103 side melts, it is reinforced and fixed with an adhesive or the like so that the parts do not come off,
It is necessary to use a high melting point solder such as b-5Sn or Pb-10Sn. In the former case, the process becomes complicated,
In the latter case, high heat resistance is required for the substrate material and circuit components, and thus there is a problem that the material cost is increased.

Further, although the ratio of surface mount components is increasing, at present, DIP (Dual Inline Package)
And the like, and it is necessary to mount the semiconductor chip and the insertable component on the same substrate. However, the multilayer circuit board 1 having the inner via holes 14a to 14c
Since No. 02 has no through hole, it is difficult to mount an insertion type component.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is simple in mounting circuit components even when a normal heat-resistant substrate material or circuit components are used. The present invention provides a circuit board and a method for manufacturing the same, which can mount the same and the insertion-type component on the same board and can increase the density.

[0011]

According to the first aspect of the present invention, a plurality of wirings are stacked with an insulating plate interposed between the wirings, and the upper and lower wirings penetrate all the insulating plates. A circuit board connected through a through hole, wherein a plurality of wirings are laminated on a part of the circuit board with an interlayer insulating film interposed between the wirings, and the upper and lower wirings are formed on the lower wirings. A circuit board provided with a multilayer wiring portion connected through an inner via hole of the formed interlayer insulating film, and a component mounting surface of the circuit board including a surface of the multilayer wiring portion is substantially flat; The second invention is solved by the circuit board according to the first invention, wherein the multilayer wiring portion is formed in a concave portion or a cutout of the circuit board.
The wiring in the multilayer wiring part and the wiring in the circuit board are connected through a through hole penetrating the multilayer wiring part and the circuit board below the multilayer wiring part. According to a fourth aspect of the present invention, there is provided a circuit board according to a second aspect, wherein the wiring in the multilayer wiring part having the inner via hole and the wiring in the circuit board below the multilayer wiring part are: Wherein the connection is made through a connection hole of the multilayer wiring portion.
A wiring board and an interlayer insulating film are alternately laminated on an insulating substrate, and the wirings above and below the interlayer insulating film are connected through an inner via hole. Preparing a partial substrate consisting of
A step of preparing a plurality of insulating plates on which wiring is formed, such that a concave portion or a cutout portion is formed by superimposing a plurality of sheets, and stacking the plurality of insulating plates, and forming the portion in the concave portion or the cutout portion. A step of placing a substrate, a step of fixing the plurality of insulating plates and the partial substrate, and a step of forming a through hole penetrating all the insulating plates, and connecting wirings of the upper and lower insulating plates through the through holes. Forming a through-hole penetrating the partial substrate and all the insulating plates below the partial substrate, and connecting wiring in the partial substrate and wiring of the insulating plate through the through-hole; A sixth aspect of the present invention provides a circuit board manufacturing method,
A step of preparing a partial substrate in which wiring and interlayer insulating films are alternately laminated on an insulating substrate, and a connection hole connected to any of the wirings is formed in the insulating substrate, A step of preparing a plurality of insulating plates on which wiring is formed, such that a concave portion or a cutout portion is formed by superimposing sheets; and overlapping the plurality of insulating plates, and forming the partial substrate in the concave portion or the cutout portion. Placing the plurality of insulating plates and the partial substrate, and connecting the wiring in the partial substrate and the wiring of the insulating plate through a connection hole of the insulating substrate of the partial substrate; Forming a through-hole penetrating all the insulating plates, and connecting the wirings of the upper and lower insulating plates through the through-holes. Yes, before A conductive film connected to a wiring on the insulating substrate through a connection hole of the insulating substrate, a bonding insulating film having an opening on the conductive film, According to a sixth aspect of the present invention, there is provided a method for manufacturing a circuit board, wherein a conductive adhesive or a low melting point alloy material embedded in an opening of an insulating film for use is formed.

In the present invention, a multilayer wiring portion in which upper and lower wirings are connected to each other through a via hole in an interlayer insulating layer is connected to a part of a circuit board in which upper and lower wirings are connected through a through hole penetrating the circuit board. Having. That is, the circuit board has a wiring connection region formed by inner via holes and a wiring connection region formed by through holes. Further, the wiring in the multilayer wiring part and the wiring of the circuit board other than the multilayer wiring part are connected through a through hole penetrating both the multilayer wiring part and the circuit board thereunder, or a connection hole of the multilayer wiring part. Connected through.

Incidentally, the distance between adjacent inner vias can be made narrower than the distance between adjacent through holes. Moreover,
The inner via is formed only in the interlayer insulating film interposed between wirings of different layers to be connected, while the through hole extends not only between the wirings of different layers to be connected but also the entire circuit board. For this reason, although the wiring density cannot be increased so much in the wiring connection region by the through hole, the through hole is exposed to the component mounting region, so that the insertion type component can be mounted. On the other hand, in a wiring connection region formed by inner vias, insertion-type components cannot be mounted because there is no through hole, but the wiring density can be increased.

Therefore, since a region having a high wiring density and a region having a through-hole are present on the same circuit board, for example, an insertion-type component or a large-sized circuit component is mounted in a wiring connection region formed by the through-hole, and an inner via By mounting a component such as a chip that requires a large number of lead-out electrodes and needs high-density wiring in the wiring connection region, a semiconductor chip, an insertion-type component, and other necessary components can be mounted on the same circuit board.

Further, since the wiring connection region (partial substrate) by the inner via and the wiring connection region (circuit substrate other than the partial substrate) by the through-hole are formed on the same circuit substrate,
All necessary parts can be mounted by one heating / welding. Therefore, the heating time for welding does not shift depending on the mounted components as in the case of mounting the conventional MCM substrate. For this reason, one welding material that melts at the same temperature can be used, and it is not necessary to use a particularly heat-resistant board material or component material in a part of the circuit board or the circuit component.

Further, when a low-melting alloy material is used as a conductive material for connecting the wiring in the partial substrate and the wiring in the circuit board other than the partial substrate, the low-melting alloy material is previously set on the back surface of the partial substrate. Embedded in the insulating film for bonding, and the partial substrate and the circuit board can be brought into close contact with each other by hot pressing or the like. It does not seep out between. Therefore, it is not necessary to use an unusual high melting point alloy material as the conductive material.

As described above, a circuit component using a normal component material can be mounted on a circuit board using a normal substrate material by a simple operation. Further, the area of the wiring density corresponding to the number of lead electrodes of the circuit component can be set to a size corresponding to the number of circuit components to be mounted. For this reason, the density of the circuit board can be increased.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (1) First Embodiment (Method of Producing Thin Film Multilayer Substrate (Partial Substrate)) FIGS.
(E) is a sectional view showing a method for producing a thin-film multilayer substrate according to the first embodiment of the present invention. The following (a)
Through the steps (e) to (e), the thin film multilayer substrate 111 is completed.

(A) First, as shown in FIG. 1A, a bismaleimide-triazine resin (BT resin) substrate (insulating substrate) having a length of 2 inches and a width of 0.9 mm and filled with silica powder is used. 21 is prepared. (B) A 10 μm thick Cu film 22 is formed thereon by electroless plating as shown in FIG. 1 (b).

(C) Next, as shown in FIG.
After a photoresist film 23 is formed on the Cu film 22, the photoresist film 23 is exposed and then developed to leave the photoresist film 23 in a region where a wiring is to be formed. Next, the Cu film 22 is etched and removed by using the photoresist film 23 remaining in the region where the wiring is to be formed as a mask to form a wiring 22a having a minimum line width of 60 μm.

(D) Next, as shown in FIG.
A photosensitive polyfunctional acrylic resin film 24a having a thickness of 30 μm is formed on the wiring 22a. Subsequently, after exposing the area other than the area where the inner via is to be formed, the substrate is immersed in a developing solution and developed, and the unexposed part is eluted to form the inner via (inner via hole).
25a is formed. As described above, the interlayer insulating film 2 having the first-layer wiring 22a and the inner via 25a covering the first-layer wiring 22a
4a is formed.

(E) Subsequently, the above-mentioned steps (b) to (d) are repeated, and the interlayer insulating films 24b and 24c having the second and later wirings 22b and 22c and the inner vias 25b and 25c covering the wirings of the respective layers are formed. Form. Further, pads for mounting components other than the wiring 22d are formed on the uppermost portion. As described above, the thin film multilayer substrate 111 is completed.

(Method of Forming Circuit Board) FIGS.
(C) is a sectional view showing a method for producing a circuit board in which the thin-film multilayer board 111 is inserted into a circuit board. First, as shown in FIG. 2A, a glass epoxy plate 31a on which a wiring 32a and an electrode 32e formed of a copper film having a line width of 0.2 mm and an appropriate length are formed, and a glass epoxy plate 31b on which a wiring 32b is formed. Create

Further, the same wirings 32c and 32 as described above
d or glass epoxy plate 31c to which electrode 32f is attached
Three pieces 31e, in which openings OP1 to OP3 of 2 inches in length and width are formed in advance in a portion where the thin-film multilayer substrate 111 is to be inserted, are prepared. The openings OP1 to OP3 are formed, for example, by punching a glass epoxy plate. The thickness of each of the five glass epoxy plates 31a to 31e is approximately 0.3 mm.

Next, a 0.05 mm-thick epoxy prepreg film 33a to 33d was
1a to 31e and sandwich them. At this time, the two glass epoxy plates 31a and 31 having no openings are formed.
b, and three glass epoxy plates 31c to 31e having openings are stacked thereon. At this time, the three glass epoxy plates 31c to 31e are overlapped so that the openings OP1 to OP3 exactly coincide with each other. Glass epoxy board 31
In the epoxy prepreg films 33c and 33d sandwiched between c and 31d and the glass epoxy plates 31d and 31e, openings of the same size are formed at the same positions as the openings of the glass epoxy plates 31c to 31e. No openings are formed in the other epoxy prepreg films 33a and 33b. Therefore, the epoxy prepreg film 33b is laid on the bottom of the concave portion formed by the overlap of the openings OP1 to OP3, and the thin film multilayer substrate 1
11 is put on the epoxy prepreg film 33b.

Next, as shown in FIG. 2B, a concave portion 115 formed by overlapping the openings OP1 to OP3.
The above-mentioned thin-film multilayer substrate 111 is hot-pressed at a temperature of 180 ° C. and a pressure of 10 atm to fix them together. The glass epoxy plate 31
The circuit board 112 is formed by stacking five boards a to 31e.

As described above, the thin film multilayer substrate (partial substrate) 1
After forming the circuit board 112 in which the substrate 11 is inserted, FIG.
As shown in (c), a portion where the glass epoxy plates 31a to 31e of the circuit board 112 are laminated and a portion where the wiring is connected between layers, and the mutual connection between the wires in the thin film multilayer board 111 and the wires in the circuit board 112. Portions to be connected are formed by drilling to form through holes (through holes) 34a to 34d.

Subsequently, after the insides of the through holes 34a to 34d are activated in the same manner as when a general printed circuit board is formed, electroless plating is performed to perform through holes 34a to 34d.
Copper films 35a to 35d are formed on the inner wall of. This allows
While connecting the wiring of different layers to be connected,
The wiring in the thin-film multilayer substrate 111 and the wiring in the circuit board 112 are connected.

As described above, the circuit board is completed. Thereafter, as shown in FIG. 2C, while the circuit board is being heated, the LSI chip 122 is mounted on the thin film multilayer substrate 111 via solder or the like, and is inserted into the circuit board 112 other than the thin film multilayer substrate 111. After placing the components 121 and the circuit components 123 having a relatively low wiring density via solder or the like, the components are cooled and fixed to complete the circuit device.

As described above, in the circuit board according to the first embodiment of the present invention, in the circuit board 112 in which different layers of the multilayer wiring are connected through the through holes 34a and 34d, Wirings of different layers among the wirings are inner vias 25a of interlayer insulating films 24a to 24c.
Through the thin film multilayer substrate 111 connected through the wiring board 25c.
The wirings inside are the thin film multilayer board 111 and the circuit board 112
Are connected through through holes 34b and 34c penetrating through.

Incidentally, the adjacent inner vias 25a to 25a-2
The interval between 5c may be narrower than the interval between adjacent through holes 34a to 34d. Moreover, Innavia 25a
25c are formed only in the interlayer insulating films 24a to 24c interposed between the wirings of different layers to be connected, while the through holes 34a to 34d are formed not only between the wirings of the different layers to be connected but also Are formed over the entire circuit board 112.

For this reason, in the circuit board 112 other than the thin-film multilayer board 111, the wiring density cannot be increased so much. However, since the through holes 34a to 34d are exposed in the component mounting area, insertion type components can be mounted. On the other hand, in the thin-film multilayer substrate 111, since the inner vias 25a to 25c are not exposed to the component mounting area, insertion type components cannot be mounted, but the wiring density can be increased.

Therefore, since a region having a high wiring density and a region having through holes 34a to 34d are present on the same circuit board, an insertion type component or a large-sized circuit component is mounted in the region having through holes 34a to 34d. By mounting a component having a large number of lead electrodes such as a chip in a region having a high wiring density, a semiconductor chip, an insertion component, and other necessary components can be mounted on the same circuit board.

In addition, the thin film multilayer substrate 111 is
Since it is formed integrally with the substrate 12, all necessary components can be mounted by heating and welding once. Therefore, the heating time for welding does not shift depending on the mounted components as in the case of mounting the conventional MCM substrate. For this reason, one welding material that melts at the same temperature can be used, and it is not necessary to use a particularly heat-resistant board material or component material in a part of the circuit board or the circuit component.

As described above, a circuit component using a normal component material can be mounted on a circuit board using a normal substrate material by a simple operation. Further, the area of the wiring density corresponding to the number of lead electrodes of the circuit component can be set to a size corresponding to the number of circuit components to be mounted. For this reason, the density of the circuit board can be increased.

(2) Second Embodiment In the second embodiment, the difference from the circuit board according to the first embodiment is that the base substrate (insulating substrate) 41 of the thin-film multilayer substrate 113 is provided in advance. Inter-substrate connection holes 44a, 44b penetrating the base substrate 41 are formed, and the front and rear electrodes 42a, 4b are formed through the inter-substrate connection holes 44a, 44b.
3 are connected to each other, and the inter-substrate connection holes 44a, 44
4b is that the conductive adhesives 55a and 55b are embedded. Then, the wiring in the circuit board 114 and the wiring in the thin film multilayer substrate (partial substrate) 113 are connected via the conductive adhesives 55a and 55b of the inter-substrate connection holes 44a and 44b.

(Method of Making Thin Film Multilayer Substrate (Partial Substrate))
FIGS. 3A to 3D and FIGS. 4A to 4C are cross-sectional views showing a method for manufacturing a thin-film multilayer substrate according to the second embodiment of the present invention. (A) First, as shown in FIG. 3A, electrodes or wirings 42a and 43 are formed on both sides of a glass epoxy substrate (insulating substrate) 41 having a length and width of 2 inches and a thickness of 0.8 mm. Subsequently, through holes (connection holes) passing through electrodes or wirings 42a and 43 at both ends of the glass epoxy plate 41 are provided.
44a, 44b are formed, and conductive films 45a, 4
5b is formed to connect the electrodes or wirings 42a, 43 on both surfaces. Next, epoxy resins 46a and 46b are filled in the through holes 44a and 44b.

(B) Next, as shown in FIG.
Thickness 55 with adhesive layers made of acrylic resin formed on both sides
An interlayer insulating film 47a made of a μm polyimide film and a Cu foil 48 having a thickness of 10 μm are laminated on the glass epoxy substrate 41 in this order. (C) Next, as shown in FIG.
After a photoresist film 49 is formed on the substrate 8, the photoresist film 49 is exposed and then developed to form an opening of the photoresist film 49 in a region where an inner via hole is to be formed.

Subsequently, the Cu foil 48 is etched through the opening of the photoresist film 49 to expose the polyimide film 47a. Next, the entire surface is irradiated with a KrF excimer laser, and the polyimide film 47a exposed in the opening of the photoresist film 49 is etched and removed by laser ablation to remove the Cu foil 48b.
Then, an opening (inner via hole) 50a penetrating through the polyimide film 47a is formed.

(D) Next, as shown in FIG. 3D, after removing the photoresist film 49, the Cu film 51 is formed by electroless plating in the opening 50a and on the Cu foil 48b.
b is formed. (E) Next, as shown in FIG. 4A, after a photoresist film 52 is formed, exposure is performed, and then development is performed to leave the photoresist film 52 in a region where a wiring is to be formed. Using the photoresist film 52 as a mask, the Cu film 51b and C
u foil 48b is etched and removed to obtain a minimum line width of 60
A second layer wiring 42b of μm is formed.

As described above, the interlayer insulating film 47a having the first and second wiring layers 42a and 42b and the inner via hole 50a interposed therebetween is formed. (F) Subsequently, the above steps (b) to (e) are repeated, and as shown in FIG. 4B, an interlayer insulating film 47b, a third-layer wiring 42c, and an interlayer insulating film 47c are sequentially formed. Further, a fourth-layer wiring and a pad 42d for mounting components are formed on the uppermost interlayer insulating film 47c.

(G) After the four-layer wiring is formed as described above, an epoxy prepreg film (adhesive insulating film) 53 is placed on the back surface of the insulating substrate as shown in FIG. The prepreg film 53 is adhered by heating to a temperature of about 120 ° C. at which the prepreg film 53 does not cure. Next, the electrode 43 and the conductive film 45 are partially irradiated with an excimer laser.
The epoxy prepreg film 53 on a and 45b is removed.

Next, conductive adhesives 55a and 55b made of silver powder and a thermosetting epoxy resin are applied to the electrodes 4 by printing.
3 and the conductive films 45a and 45b. As described above, the thin film multilayer substrate 113 is completed. (Method of Manufacturing Circuit Board) FIGS. 5A to 5C are cross-sectional views illustrating a method of manufacturing a circuit board according to the second embodiment of the present invention.

First, as shown in FIG. 5A, the same epoxy prepreg films 63a to 63a as in the first embodiment are used.
Five glass epoxy plates 61a to 61e, which are the same as those in the first embodiment, are stacked so as to form a concave portion 116 into which the thin-film multilayer substrate 113 is inserted, with 3d interposed therebetween. At this time,
An opening is formed in the epoxy prepreg film 63b, and on the upper surface of the glass epoxy plate 61b of the second layer, in addition to the wiring of the first embodiment, the conductive adhesive of the back surface of the thin film multilayer substrate 113 is provided. An electrode or wiring 62b to be connected to the agents 55a and 55b is formed. Therefore, the electrode or wiring 62b is exposed at the bottom of the concave portion 116 and comes into contact with the conductive adhesives 55a and 55b of the thin film multilayer substrate 113.

Next, the above-mentioned thin film multilayer substrate 113 placed in the concave portion 116 of the circuit board is heated at a temperature of 180 °.
Hot pressing is performed at a temperature of 10 ° C. and a pressure of 10 atm. At this time, the electrodes 43 and the conductive films 45a and 45b on the back surface of the thin-film multilayer substrate 113 and the electrodes or wirings 62b on the second-layer glass epoxy substrate 61b are pressed together via the conductive adhesives 55a and 55b. A circuit board 114 other than the thin film multilayer board 113 constitutes a circuit board in which five glass epoxy plates 61 a to 61 e are stacked.

Then, heating is performed to obtain an electrical connection between the electrodes and the conductive films 45a and 45b on the back surface of the thin-film multilayer substrate 113 and the electrodes or wirings 62b on the second-layer glass epoxy plate 61b. After forming the circuit board 114 in which the thin-film multilayer board 113 is inserted as described above, a portion where the glass epoxy plates 61a to 61e of the circuit board 114 are to be connected to form an interlayer connection is drilled to form a through hole. (Through holes) 64a and 64b are formed.

Subsequently, after activating the insides of the through holes 64a and 64b, the through holes 64a and 64b are electrolessly plated.
Copper films 65a and 65b are formed on the inner walls of a and 64b. Thus, wires of different layers to be connected are connected to each other. Thus, a circuit board is completed. Then, FIG.
As shown in (c), while the circuit board is heated, the LSI chip 12 is placed on the thin-film multilayer board 113 via solder or the like.
2 on a circuit board 114 other than the thin-film multilayer board 113, the insertion-type component 121 or the circuit component 1 having a relatively low wiring density.
23 is placed via solder or the like, then cooled and fixed to complete the circuit device.

As described above, in the circuit board according to the second embodiment of the present invention, similarly to the first embodiment, the region having a high wiring density and the through holes 64a, 64b
Is located on the same circuit board, so that insert-type components or large-sized circuit components are mounted in the regions having the through holes 64a and 64b, and the number of lead-out electrodes such as chips is large in the region with high wiring density. By mounting the components, the semiconductor chip, the insertion type component, and other necessary components can be mounted on the same circuit board.

Further, the thin film multilayer substrate 113 is
4 and is integrally formed, so that all necessary components can be mounted by heating and welding once. For this reason, one welding material that melts at the same temperature can be used, and it is not necessary to use a particularly heat-resistant board material or component material in a part of the circuit board or the circuit component.

As described above, a circuit component using a normal component material can be mounted on a circuit board using a normal substrate material by a simple operation. Further, the area of the wiring density corresponding to the number of lead electrodes of the circuit component can be set to a size corresponding to the number of circuit components to be mounted. For this reason, the density of the circuit board can be increased.

In the second embodiment, the conductive adhesives 55a and 55b are used as conductive materials for connecting the wiring in the thin-film multilayer substrate 113 and the wiring in the circuit board 114 other than the thin-film multilayer substrate 113. Although a low melting point alloy material such as solder may be used. In this case, the low melting point alloy material is embedded in the openings 54a and 54b of the bonding insulating film 53 on the lower surface of the second substrate in advance, and
4 and the thin-film multilayer substrate 113 are in close contact with each other by hot pressing, so that even if they are melted by heating when mounting components, they do not seep into gaps between layers of the circuit board. Therefore, since a high melting point alloy material need not be used as the conductive material, a circuit component using a normal component material can be mounted on a circuit board using a normal substrate material by a simple operation.

In the first and second embodiments, the circuit board 112, which is a wiring connection area by a through hole,
Although the partial substrates (wiring connection regions by inner vias) 111 and 113 are mounted in the concave portions 115 and 116 of the 114, as shown in FIG. 6 which is exemplified using the circuit substrate 112 of the first embodiment, The partial substrate (wiring connection region by inner via) 111 may be mounted in the cutout 117 of the 112.

The circuit boards 112 and 114 for stacking and fixing a plurality of insulating boards and the mounting of the partial boards 111 and 113 on the circuit boards 112 and 114 are simultaneously performed. May be stacked and fixed to form a circuit board 112 having a concave portion or a cutout portion, and then the partial substrates 111 and 113 may be mounted in the concave portion or the cutout portion.

[0054]

As described above, according to the present invention, a multilayer wiring portion in which the interlayer wirings are connected to each other through a so-called inner via hole is provided on a part of the circuit board where the interlayer wirings are connected through the through holes. Is provided. That is, since the region having a high wiring density and the region having the through-hole exist on the same circuit board, the semiconductor chip, the insertion type component, and other necessary components can be mounted on the same circuit board.

Further, since the wiring connection region (partial substrate) by the inner via hole and the wiring connection region (circuit substrate other than the partial substrate) by the through hole are formed integrally,
All necessary components can be mounted in the component mounting area by a single heating and welding process, and there is no need to shift the heating timing. Therefore, it is possible to use one welding material that melts at the same temperature, and it is not necessary to use a particularly heat-resistant board material or component material for a part of the circuit board or the circuit component.

When a low-melting-point alloy material is used to connect the wiring in the partial substrate to the wiring in the circuit board other than the partial substrate, the low-melting-point alloy material may be used as a bonding insulating material on the lower surface of the partial substrate in advance. Since it is embedded in the opening of the film, even if the low-melting alloy material is melted by heating at the time of mounting components, it does not seep into the gap between the partial board and the circuit board. Therefore, it is not necessary to use an unusual high melting point alloy material as the conductive material.

As described above, a circuit component using a normal component material can be mounted on a circuit board using a normal substrate material by a simple operation. In addition, the area of the wiring density according to the number of lead electrodes of the circuit component can be set to a size corresponding to the number of circuit components to be mounted, so that the density of the circuit board can be increased.

[Brief description of the drawings]

FIGS. 1A to 1E are cross-sectional views showing a method for producing a thin-film multilayer substrate according to a first embodiment of the present invention.

FIGS. 2A to 2C are cross-sectional views illustrating a method for manufacturing a circuit board according to the first embodiment of the present invention.

FIGS. 3A to 3D are cross-sectional views (part 1) illustrating a method for manufacturing a thin-film multilayer substrate according to a second embodiment of the present invention.

FIGS. 4A to 4C are cross-sectional views (part 2) illustrating a method of manufacturing a thin-film multilayer substrate according to a second embodiment of the present invention.

FIGS. 5A to 5C are cross-sectional views illustrating a method of manufacturing a circuit board according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a circuit board according to another embodiment of the present invention.

FIGS. 7A to 7C are cross-sectional views illustrating a method of manufacturing a circuit board according to a conventional example.

FIG. 8 is a sectional view showing a thin-film multilayer substrate according to a conventional example.

FIG. 9 is a cross-sectional view showing a circuit device according to a conventional example in which circuit components are mounted on a circuit board.

[Explanation of symbols]

21 BT resin substrate (insulating substrate), 22 Cu film, 22a to 22d, 32a to 32f, 42a to 42d, 6
2a to 62f Wiring or electrode, 23, 49, 52 Photoresist film, 24a to 24c, 47a to 47c Interlayer insulating film, 25a to 25c, 50a to 50c Inner via hole (via hole), 31a to 31e, 61a to 61e Glass epoxy plate (Insulating plate), 33a-33d, 63a-63d epoxy prepreg film, 34a-34d, 64a, 64b through hole (through hole), 35a-35d, 65a, 65b copper film, 41 glass epoxy substrate (insulating substrate), 43, 44a, 44b through hole (connection hole), 45a, 45b conductive film, 46a, 46b epoxy resin, 47a to 47c polyimide film (interlayer insulating film), 48, 48b Cu foil, 51b Cu film, 53 epoxy prepreg film ( Insulating film for bonding), 54a, 54b opening, 55a, 55b conductive adhesive, 111, 113 thin-film multilayer substrate (partial substrate), 112, 114 circuit board, 115, 116 recess, 117 notch, 121 insertion type component, 122 LSI chip, 123 circuit component .

Claims (7)

[Claims] 1. A circuit board wherein a plurality of wirings are stacked with an insulating plate interposed between the wirings, and the upper and lower wirings are connected to each other through through holes penetrating all the insulating plates. A multilayer in which a plurality of wirings are stacked on a part of a substrate with an interlayer insulating film interposed therebetween, and the upper and lower wirings are connected to each other through inner via holes of an interlayer insulating film formed on the lower wirings. A circuit board, wherein a wiring portion is provided, and a component mounting surface of the circuit board including a surface of the multilayer wiring portion is substantially flat. 2. The circuit board according to claim 1, wherein the multilayer wiring portion is formed in a recess or a cutout of the circuit board. 3. The wiring in the multilayer wiring part and the wiring in the circuit board are connected through a through hole penetrating the multilayer wiring part and the circuit board below the multilayer wiring part. The circuit board according to claim 2, wherein: 4. The wiring in the multilayer wiring portion having the inner via hole and a wiring in a circuit board below the multilayer wiring portion are connected through a connection hole in the multilayer wiring portion. Item 3. The circuit board according to item 2. 5. A step of preparing a partial substrate in which wirings and interlayer insulating films are alternately laminated on an insulating substrate, and connecting upper and lower wirings of the interlayer insulating film through inner via holes; A step of preparing a plurality of insulating plates on which wiring is formed such that a concave portion or a cutout portion is formed by superimposing; and placing the partial substrate in the concave portion or the cutout portion while overlapping the plurality of insulating plates. Fixing the plurality of insulating plates and the partial substrate, forming a through hole penetrating all the insulating plates, and connecting wirings of the upper and lower insulating plates through the through holes; Forming a through-hole penetrating the partial substrate and all of the insulating plates below the partial substrate, and connecting wiring in the partial substrate and wiring of the insulating plate through the through-hole. Characterized by Method of manufacturing a circuit board. 6. A step of preparing a partial substrate in which wirings and interlayer insulating films are alternately laminated on an insulating substrate and connection holes connected to any of the wirings are formed in the insulating substrate. A step of preparing a plurality of insulating plates on which wiring is formed, such that a concave portion or a cutout portion is formed by superimposing sheets; and superposing the plurality of insulating plates, and forming the partial substrate in the concave portion or the cutout portion. Placing the plurality of insulating plates and the partial substrate together, and connecting a wiring in the partial substrate and a wiring of the insulating plate through a connection hole of the insulating substrate of the partial substrate; Forming a through-hole penetrating all the insulating plates, and connecting the wiring of the upper and lower insulating plates through the through-holes. 7. The lower surface of the insulating substrate of the partial substrate,
A conductive film connected to a wiring on the insulating substrate through a connection hole of the insulating substrate; a bonding insulating film having an opening on the conductive film; and a conductive film embedded in the opening of the bonding insulating film. 7. The method for manufacturing a circuit board according to claim 6, wherein a conductive adhesive or a low melting point alloy material is formed.