JPH0450760B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a method for manufacturing a multilayer wiring board, and particularly to a method for manufacturing a multilayer wiring board in which the formation of a second layer conductive pattern is improved.

(b) Prior Art A conventional method for manufacturing a multilayer wiring board will be described with reference to FIGS. 2A to 2C.

First, as shown in FIG. 2A, a first conductive pattern 12 is formed on an insulating substrate 11. Insulating substrate 11
It is formed by using ceramics or the like as a material, and by adhering copper foil to the entire surface of the substrate 11 and then etching it into a desired pattern.

Subsequently, as shown in FIG. 2B, an interlayer insulating film 13 is formed to cover the first conductive pattern 12,
A through hole 14 is formed on a desired first conductive pattern 12. As the interlayer insulating film 13, a polyimide layer, a permanent photoresist layer, or the like is used.

Furthermore, as shown in FIG. 2C, a second conductive pattern 15 is formed on the interlayer insulating film 13 by electroless copper or nickel plating. Second conductive pattern 15
is connected to the first conductive pattern 12 via the through hole 14 to realize a multilayer structure.

The method for manufacturing such a multilayer wiring board is disclosed in Japanese Patent Application Laid-Open No. 1986-
No. 10697.

(c) Problems to be solved by the invention In the above conventional method, the second conductive pattern is formed by electroless plating of copper or nickel, so it must be formed to have a thickness of 30 μm or more in order to form a conductive path. to 24
There was a problem that required more time.

(d) Means for solving the problems The present invention has been made in view of the above-mentioned problems, and includes a step of forming a first conductive pattern on an insulating substrate, and a step of forming a first conductive pattern on the first conductive pattern. After forming a resin coat film that surrounds a part of the conductive pattern and providing openings and holes for via holes corresponding to the resin coat film in the resin layer with metal foil, the resin layer with metal foil is coated with a first conductive layer. a step of pasting it on the pattern; a step of electroplating the via hole to connect the first conductive pattern and the metal foil;
The present invention is solved by including a step of forming a second conductive pattern by etching the metal foil.

(E) Effect As described above, according to the present invention, a resin coat film surrounding a part of the pattern is formed on the first conductive pattern, and the openings and via holes corresponding to the resin coat film are coated with metal foil. By providing the metal foil on resin and pasting it on the first conductive pattern, the second conductive pattern can be formed by etching the metal foil, and the second conductive pattern can be formed in a short time.

(F) Embodiments The present invention will be described in detail below based on the embodiments shown in FIGS. 1A to 1H.

First, as shown in FIG. 1A, a first
A conductive pattern 2 is formed. The insulating substrate 1 is made of ceramics or aluminum whose surface is coated with an oxide film, and the first conductive pattern 2 is formed by pasting copper foil over the entire surface of the substrate 1 and then etching it into a desired pattern.

Next, as shown in FIG. 1B, a resin coat film 3 surrounding a portion of the first conductive pattern 2 is formed on the first conductive pattern 2. Then, as shown in FIG. The resin coat film 3 is formed by printing a resin such as epoxy resin so as to overlap the first conductive pattern 2 . That is, the first conductive pattern 2 is formed in a frame shape so as to overlap with the first conductive pattern 2 around the pad 2' to which the semiconductor element is fixed, and to surround the periphery of the pad 2' to which the semiconductor element is fixed. Form. The thickness and width of the resin coat film 3 can be arbitrarily selected, and in this example, the thickness is
It shall be formed with a thickness of 15μ and a width of approximately 1.5mm.

Next, as shown in FIG. 1C, after providing an opening 4 corresponding to the resin coat film 3 and a hole 5 for a via hole in the resin 6 with metal foil, the resin layer 6 with metal foil is placed on the insulating substrate 1. Paste. As the resin 6 with metal foil, a so-called flexible sheet in which an insulating resin 8 such as a polyimide resin and a copper foil 7 are integrated is used.
In this resin 6 with metal foil, an opening 4 corresponding to the frame-shaped resin coat film 3 and a hole 5 for a via hole for multilayer wiring with the first conductive pattern 2 are formed in advance by punching or the like. It is bonded by thermocompression onto the entire surface of the substrate 1. At this time, consideration is given so that the end edge of the resin 6 with metal foil inside the opening 4 is located near the center on the resin coat 3.

Next, as shown in FIG. 1D, a dry film 9 is thermocompressed onto the substrate 1 at about 80 DEG to 100 DEG C. to adhere to the entire surface of the substrate 1.

Next, as shown in FIG. 1E, the multilayer wiring hole 5 and the surrounding dry film 9 are removed by photolithography to form a via hole.

Next, as shown in FIG. 1F, the via hole is electroplated to connect the first conductive pattern 2 and the copper foil 7.

As shown in FIG. 1E, the via hole and the copper foil 7 around the via hole are exposed, electroless copper plating is performed, the first conductive pattern 2 and the copper foil 7 are connected, and the remaining dry film is removed. Remove 9.

Next, as shown in FIGS. 1G and 1H, the copper foil 7
A second conductive pattern 10 is formed by etching. After removing the dry film, the dry film is thermocompression bonded to the entire surface of the insulating substrate 1 again, and photolithography is applied to form the second conductive pattern 10 on the copper foil 7 and in the resin coat film 3, as shown in FIG. 1G. After leaving the dry film 9' only on the first conductive pattern 2 and removing the other parts, the copper foil 7 is etched to form the second conductive pattern 2 on the first conductive pattern 2, as shown in FIG. 1H. A conductive pattern 10 can be formed. That is, as shown in FIG. 1I, the pad 2' to which the semiconductor element is fixed is surrounded by a frame-shaped resin coat film 3, and the first pad 2' is surrounded by a frame-shaped resin coat film 3.
The tip of the conductive pattern 2 is formed to extend to the vicinity of the pad 2'. And on pad 2',
Although not shown, a semiconductor element is fixed and connected to the first conductive pattern 2 in the periphery.

In the step shown in FIG. 1G, if the dry film 9' is left on the first conductive pattern 2 in the resin coat film 3, it can be formed in a fine pattern by photolithography; etc., a minute gap is generated between the dry film 9' and the insulating resin 8, and when etching the copper foil, there is a risk that etchant may enter through the gap and etch the first conductive pattern 2. However, in the present invention, the resin coat film 3 is Therefore, there is no fear that the first conductive pattern 2 will be etched.

(g) Effects of the invention As detailed above, according to the present invention, the second conductive pattern can be formed of copper foil,
Disconnection of the second conductive pattern can be prevented.

Further, in the present invention, since an opening is provided,
Since the circuit element can be fixed onto the first conductive pattern, a circuit element that generates heat can be mounted without impairing thermal resistance.

[Brief explanation of the drawing]

1A to 1I are sectional views and plan views showing an embodiment of the present invention, and FIGS. 2A to 2C are sectional views showing a conventional example. 1... Insulating substrate, 2... First conductive pattern,
3... Resin coat film, 4... Opening, 5... Hole,
6... Resin with metal foil, 7... Copper foil, 8... Insulating resin, 9, 9'... Dry film, 10... Second conductive pattern.

Claims (1)

[Scope of Claims] 1. A step of forming a first conductive pattern on an insulating substrate; A step of forming a frame-shaped resin coat film surrounding a part of the pattern on the first conductive pattern; After providing an opening corresponding to an area surrounded by a resin coat film and a hole for a via hole in the resin layer with metal foil, adhering the resin layer with metal foil onto the insulating substrate; forming a via hole by electroplating to connect the first conductive pattern and the metal foil; forming a resist film on the substrate, and forming an opening region overlapping at least the resin coat film; and a step of leaving the resist film on the via hole and etching the metal foil to form a second conductive pattern.