Dielectric circuit board bonding

Claim 2

A process for the manufacture of microwave stripline circuit boards or the like including: A. attaching together a relatively thick, partly cured dielectric substrate of thermosetting plastic material and a sheet of bonding film consisting essentially of an electrically compatible heat settable plastic about 0.002 in. thick to form a dielectric laminate; B. attaching a conductive foil to said film to form a clad composite board; C. pressing said composite board between temperature controlled press plates sufficiently to cause said conductive material and said substrate to be adhered by said film while said substrate remains partly uncured; D. etching away portions of said conductive material to form a desired electrical circuit; E. machining said board to finished size and shape; F. placing the etched and machined board in a mold container confining said board in all dimensions; G. pressing the board at a controlled temperature and pressure sufficient to completely cure said film and substrate and cause said conductor and said film to form together a flush level board surface.

Claim 3

The process of claim 1 wherein said conductive foil is copper and said bonding film is a dry plastic sheet of irradiation cross-linked polyethylene.

Claim 4

The process of claim 2 wherein said substrate panel is a glass loaded sheet of tetrafluoroethylene.

Claim 5

The process of claim 1 wherein said temperature controlled plates are successively heated to about 250°F., held under 300 PSIG pressure for a predetermined time and then shock cooled to about 70°F before decreasing the pressure and removing the board from the press.

Claim 6

The process of claim 4 wherein said conductive foil is copper and said bonding film is a dry plastic sheet of irradiation cross-linked polyethylene.

Claim 7

The process of claim 5 wherein said substrate panel is a glass loaded sheet of tetrafluoroethylene.

Claim 8

The process of claim 1 including: G. placing two such boards with their conductor sides facing in a confining mold with at least one commensurate sheet of polyolefin bonding film therebetween forming a stack; H. pressing the stack and elevating the temperature to bond the two boards.

Claim 9

The process of claim 7 further including: I. placing a soft solder between portions of the conductors on the respective boards before pressing and heating to a temperature sufficient to melt said solder and electrically bind said conductors.

Claim 10

The process of claim 7 wherein said temperature controlled plates are successively heated to about 250°F., held under a pressure of about 300-350 PSIG for a predetermined time and then cooled before removing said stack from the press.

Claim 11

The process of claim 9 wherein: the temperature of said plates is elevated to 251°F. during a period of about 7 minutes; the pressure of said plates is raised during said period to 125 PSIG; the pressure and temperature is held constant for 5 minutes; and thereafter rapidly cooling said plates to about 95° before decreasing the pressure and removing said stack from the press.

Claim 12

The process of claim 10 wherein said conductive foil is copper and said bonding film is a dry plastic sheet of irradiation cross-linked polyethylene.

Claim 13

The process of claim 11 wherein said substrate panel is a glass loaded sheet of tetrafluoroethylene.

Claim 14

A process for the manufacture of circuit boards or the like including: A. bonding together a glass loaded plastic substrate panel of tetrafluoroethylene and a sheet of conductive copper foil by means of an interposed bonding film consisting essentially of a dry sheet of irradiation cross linked polyethylene to form a clad dielectric board; B. machining sections of said board to a finished size and shape desired; C. removing only sufficient patterned portions of the conductive foil from the surface of said sections to provide on those sections discrete circuit paths and leaving said circuit paths surrounded by supportive foil separated from said circuit paths; D. placing two of said selected sections foil face to foil face with a piece of electrically compatible heat settable bonding film between said foil faces to form a stack with said bonding film conforming to all peripheral dimensions and any internal shapes of said sections; E. placing said stack in a container mold having inner dimensions such as to closely receive and confine the components of said stack; F. further confining said stack by means of top and bottom mold members closely fitting within said container mold; G. heating and pressing said stack to about 250°F within the confinement of said mold; and H. chilling said mold and stack while still under pressure until the temperature of said stack drops to about 70°F or below before releasing pressure and removing the stack form the mold.

Claim 15

A process for the manufacture of circuit boards or the like including: A. bonding together a glass loaded plastic substrate panel of tetrafluoroethylene and a sheet of conductive copper foil by means of an interposed bonding film consisting essentially of a dry sheet of irradiation cross linked polyethylene to form a clad dielectric board; B. machining sections of said board to a finished size and shape desired; C. removing only sufficient patterned portions of the conductive foil from the surface of said sections to provide on those sections discrete circuit paths and leaving said circuit paths surrounded by supportive foil separated from said circuit paths; D. placing two of said selected sections foil face to foil face with a piece of electrically compatible heat settable bonding film between said foil faces to form a stack with said bonding film conforming to all peripheral dimensions and any internal shapes of said sections; E. placing said stack in a container mold having inner dimensions such as to closely receive and confine the components of said stack; F. further confining said stack by means of top and bottom mold members closely fitting within said container mold; G. heating and pressing said stack to about 250°F within the confinement of said mold; and H. chilling said mold and stack while still under pressure until the temperature of said stack drops to about 70°F or below before releasing pressure and removing the stack form the mold.