Metallization of electrically insulating polymeric film substrates

Claim 2

A process for conductively metallizing an electrically insulating thermoplastic or thermoplastic phase polymeric film substrate, comprising (1) shaping into said film substrate an intimate homogeneous admixture of a film-forming thermoplastic or thermoplastic phase polymer matrix having from 10 to 70 percent by total weight of said admixture of finely divided, non-conductive metal oxide particles uniformly distributed therein, (2) disrupting at least one face surface of said shaped film substrate to expose thereon a plurality of said finely divided, non-conductive metal oxide particles, and (3) treating said at least one disrupted face surface with a reducing agent to reduce said exposed metal oxide particles into a layer of electrically conductive free metal, whereby said at least one face surface is rendered electrically conductive.

Claim 3

The process as defined by claim 1, further comprising (4) electrolytically depositing a reinforcing, electrically conductive metallic overlayer atop said first layer of electrically conductive free metal.

Claim 4

The process as defined by claim 2, said reducing agent comprising a borohydride.

Claim 5

The process as defined by claim 3, said reducing agent comprising a substituted or unsubstituted alkali metal borohydride.

Claim 6

The process as defined by claim 3, said film substrate comprising a flexible film-forming polymer.

Claim 7

The process as defined by claim 5, said flexible film-forming polymer comprising a polyester, polyamide, polyolefin, polyphenylene oxide, polysulfide, vinyl polymer, (meth)acrylic polymer, polystyrene, fluorinated polymer, polycarbonate, elastomer, polysulfone, polyacetal, parabanic polymer, polyhydantoin, polyalkylene oxide, mixtures or copolymers thereof.

Claim 8

The process as defined by claim 3, said finely divided, non-conductive metal oxide particles comprising cuprous oxide.

Claim 9

The process as defined by claim 7, said cuprous oxide particles having a grain size distribution ranging from 0.1 to 5 microns.

Claim 10

The process as defined by claim 1, said film substrate having a surface resistivity ranging from 0.01 Ω/□ to 10 3 Ω/□ after the step (3).

Claim 11

The process as defined by claim 3, wherein said first layer of electrically conductive free metal extends into and is anchored within said shaped film substrate.

Claim 12

The process as defined by claim 10, said film-forming polymer matrix having from 30 to 50 percent by total weight of the admixture of said finely divided, non-conductive metal oxide particles uniformly distributed therein.

Claim 13

The process as defined by claim 3, said at least one face surface being disrupted by at least uniaxially stretching said shaped film substrate.

Claim 14

The process as defined by claim 12, said at least one face surface being disrupted by biaxially stretching said shaped film substrate.

Claim 15

The process as defined by claim 3, said at least one face surface being disrupted by surface abrading treatment.

Claim 16

The process as defined by claim 1, further comprising heat stabilizing said reduced film substrate.

Claim 17

The process as defined by claim 3, further comprising chemically depositing an electrically conductive metallic overlayer on said first layer of electrically conductive free metal prior to said electrolytic deposition step (4).

Claim 18

The process as defined by claim 3, the thickness of said first layer of electrically conductive free metal having a thickness on the order of about 1 micron.

Claim 19

The process as defined by claim 3, said electrolytically deposited overlayer having a thickness of at least 20 microns.

Claim 20

The process as defined by claim 3, said reduction (3) being such as to also reduce unexposed metal oxide particles located within a portion of the volume of said film substrate, but insufficient to conductively alter the electrically insulating characteristic thereof.

Claim 21

The process as defined by claim 1, said shaped film substrate having hole(s) bored therein upstream of said reducing step (3), the exposed metal oxide particles on the sidewall surfaces thereof also then being reduced into a layer of electrically conductive free metal at least as thick as said at least one face surface layer of electrically conductive free metal and being physically integral therewith.

Claim 22

The process as defined by claim 3, said borohydride reducing agent comprising a liquid solution thereof, the active hydrogen content thereof ranging from 0.05 to 1% by weight.

Claim 23

The process as defined by claim 3, a lead/tin alloy electrically conductive overlayer being electrolytically deposited atop said first layer of electrically conductive free metal.

Claim 24

The process as defined by claim 7, an electrically conductive copper overlayer being electrolytically deposited atop said first layer of electrically conductive free metal.

Claim 25

A process for the fabrication of a printed circuit comprising an electrically insulating thermoplastic or thermoplastic phase polymeric film substrate, which comprises (1) shaping into said film substrate an intimate homogeneous admixture of a film-forming thermoplastic or thermoplastic phase polymer matrix having from 10 to 70 percent by total weight of said admixture of finely divided, non-conductive metal oxide particles uniformly distributed therein, (2) disrupting at least one face surface of said shaped film substrate to expose thereon a plurality of said finely divided, non-conductive metal oxide particles, (3) treating said at least one disrupted face surface with a reducing agent to reduce said exposed metal oxide particles into a layer of electrically conductive free metal, whereby said at least one face surface is rendered electrically conductive, (4) coating said reduced and conductivised film substrate with a photosensitive resist overlayer, (5) imaging a circuit pattern onto said photosensitive resist overlayer and developing unimaged areas thereof, (6) electrolytically depositing a reinforcing, electrically conductive metallic overlayer atop said first layer of electrically conductive free metal, (7) removing photosensitive resist material therefrom, and (8) non-selectively etching said film substrate to define a conductive printed circuit pattern thereof.

Claim 26

A process for the fabrication of a printed circuit comprising an electrically insulating thermoplastic or thermoplastic phase polymeric film substrate, which comprises (1) shaping into said film substrate an intimate homogeneous admixture of a film-forming thermoplastic or thermoplastic phase polymer matrix having from 10 to 70 percent by total weight of said admixture of finely divided, non-conductive metal oxide particles uniformly distributed therein, (2) disrupting at least one face surface of said shaped film substrate to expose thereon a plurality of said finely divided, non-conductive metal oxide particles, (3) treating said at least one disrupted face surface with a reducing agent to reduce said exposed metal oxide particles into a layer of electrically conductive free metal, whereby said at least one face surface is rendered electrically conductive, (4) coating said reduced and conductivised film substrate with a photosensitive resist overlayer, (5) imaging a circuit pattern onto said photosensitive resist overlayer and developing unimaged areas thereof, (6) electrolytically depositing a reinforcing, electrically conductive metallic overlayer atop said first layer of electrically conductive free metal, (7) removing photosensitive resist material therefrom, and (8) non-selectively etching said film substrate to define a conductive printed circuit pattern thereof.

Claim 27

The process as defined by claim 24, said reducing agent comprising a borohydride.

Claim 28

The process as defined by claim 25, said finely divided, non-conductive metal oxide particles comprising cuprous oxide.

Claim 29

The process as defined by claim 24, said shaped film substrate having hole(s) bored therein upstream of said reducing step (3), the exposed metal oxide particles on the sidewall surfaces thereof also then being reduced into a layer of electrically conductive free metal at least as thick as said at least one face surface layer of electrically conductive free metal and being physically integral therewith.

Claim 30

The process as defined by claim 24, further comprising (3a) electrolytically depositing an initial reinforcing, electrically conductive metallic overlayer atop said first layer of electrically conductive free metal, prior to said step (4).

Claim 31

The product of the process as defined by claim 1.

Claim 32

The product of the process as defined by claim 3.

Claim 33

The product of the process as defined by claim 20.

Claim 34

The product of the process as defined by claim 24.

Claim 35

The product of the process as defined by claim 27.

Claim 36

The product of the process as defined by claim 24, after the step (3) thereof.

Claim 37

The product of the process as defined by claim 24, after the step (4) thereof.