Adhesive bonding and miscellaneous chemical manufacture – Delaminating processes adapted for specified product – Delaminating in preparation for post processing recycling step
Patent
1984-11-13
1985-07-09
Powell, William A.
Adhesive bonding and miscellaneous chemical manufacture
Delaminating processes adapted for specified product
Delaminating in preparation for post processing recycling step
29852, 156634, 156644, 156902, 174 685, 427 97, C23F 102, B44C 122, C03C 1500, C03C 2506
Patent
active
045280649
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a multilayer circuit board.
BACKGROUND ART
As a conventional multilayer circuit board it is known that, for example, as shown in FIGS. 1A and 1B, a so-called rigid circuit board 3 which is made by forming a first circuit pattern 2 made of copper foil on a thick insulating substrate 1 made of such as paper impregnated with phenolic resin or paper impregnated with epoxy resin and the like is laminated on and made integral with a so-called flexible circuit board 6 which is made by forming a second circuit pattern 5 made of copper foil on a film 4 made of such as polyimide resin, polyester resin and the like by way of an adhesive insulating layer (for example, epoxy resin adhesive) 7, in which the upper and lower wiring patterns 5 and 2 are connected together by conductive material 8 to form a multilayer circuit board 9. Reference numeral 10 denotes an electric device mounted on the substrate 9, and numeral 11 denotes a solder.
In the multilayer circuit board 9 thus composed, there are such disadvantages that since a distance between the upper and lower patterns 2 and 5 is so large, the connection between both the patterns 2 and 5 through the conductive material 8 is low in reliability; at a connection portion 12 of the electric component 10, both the patterns 2 and 5 can not be directly soldered together by the same solder 11 at the same time for mounting the component thereon; and a fairly small aperture with a diameter less than 1.sub.mm is difficult to be bored through the flexible circuit board 6, which results in that a high quality one or one with high density integration can not be produced. Moreover, in the case of the manufacturing, as shown in FIG. 2, when the wiring pattern 5 of the upper layer is formed by a selective etching method to remove copper foil of uncovered portions on a resist ink 13 formed by printing, the wiring pattern 2 of the lower layer facing a through-hole 14 is eroded or etched (shown by reference numeral 15 in the figure) by etchant. Therefore, it is necessary to cover or fill the through-hole 14 beforehand with resist ink, so the manufacturing process is quite complicated.
DISCLOSURE OF INVENTION
In accordance with the present invention, a conductive foil is bonded on a first circuit board with a predetermined first wiring pattern formed thereon by way of an insulating resin layer formed other than at least upper and lower connection portions, they are integrally laminated with one other by heat roll, heat press or the like, and an opening portion on the second wiring pattern made of this conductive foil which reaches the afore-described first wiring pattern (connection portion) is filled with conductive substance so as to connect the upper and lower first and second wiring patterns. In the present invention as mentioned above, a distance (step-like distance) between the afore-mentioned first and second wiring patterns at the connection portion is extremely reduced (about 5.mu. to 20.mu.), and in addition, in the opening portion as described above the edge portion of the second wiring pattern is introduced into the inside thereof, so that the conductivity between the first and second wiring patterns is improved by the afore-described conductive substance, and hence a so-called through-hole connection with high reliability can be achieved. Moreover, since the distance between the first and second wiring patterns is small or short, in the case of patterning the afore-described copper foil, the resist ink can be printed within the afore-described opening portion so that the selective etching process is made easier. Further, when the electric component is mounted by dipping in a solder bath, the afore-described first and second wiring patterns can be connected by the same solder dipping process at the connection portion of the lead wire of the electric component. Also, the opening portion of the second wiring pattern as described above can be bored by a chemical etching technique so that an opening portion of a fairly small
REFERENCES:
patent: 2447541 (1948-08-01), Sabee et al.
patent: 3311966 (1967-04-01), Shaheen et al.
patent: 3374129 (1968-03-01), Boucher
patent: 3846166 (1974-11-01), Saiki et al.
patent: 4030190 (1977-06-01), Varker
patent: 4336100 (1982-06-01), Passlick
patent: 4383363 (1983-05-01), Hayakawa et al.
patent: 4388136 (1983-06-01), Huie et al.
patent: 4420364 (1983-12-01), Nukii et al.
Ito Takao
Kurata Keiji
Ohsawa Kenji
Ohsawa Masayuki
Powell William A.
Sony Corporation
LandOfFree
Method of making multilayer circuit board does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of making multilayer circuit board, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of making multilayer circuit board will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-908010