Abstract:
A tri-metallic material for use in the manufacture of printed circuit boards is described. and the process for its manufacture is described. The tri-metallic material is a sandwich wherein a copper layer is essential the "bread" of the sandwich and an aluminum layer is the filling between both slices of bread. A metallic bonding and/or barrier layer is spread on the aluminum and is selected for its highly non-corrosive properties as well as its bonding, and diffusion inhibiting capabilities.
Abstract:
A method for forming connections within a multi-layer electronic circuit board. The method includes forming an aperture within the circuit board and selectively coating the interior surface of the aperture with a polar solder mask material that is effective to bond with solder that is selectively inserted into the aperture, thereby retaining the solder within the aperture and improving the electrical connection provided by the solder.
Abstract:
A multi-layer circuit board having strengthened air bridge crossover structures, and additive and subtractive methods for producing the same, wherein the circuit includes specially designed metallic fortifying layers (52,54) to mechanically and/or electrically fortify the circuit. A preferred embodiment includes air bridge structures (90) having generally T-shaped cross-sections (99), which provide strengthened, mechanically robust air bridges (33) which are especially resistant to damage from flexure and displacement due to physical impact, bending, thermal excursions, and the like.
Abstract:
A method of manufacturing an improved multi-layer printed circuit assembly having at least two conductor patterns. The method includes providing a first layer having a first metal surface a second layer having a second metal surface. A thin flexible carrier is placed between the first and second layers. The first and second layers are attached to opposite surfaces of the carrier. The first and second metal surfaces are etched to form first and second conductor patterns. The conductor patterns form the electrical traces interconnecting components on an electronic circuit assembly. The first and second conductor patterns are electrically connected to form an electronic circuit assembly that includes electronic traces on both sides of the circuit board.
Abstract:
An etchant useful for chemically milling aluminium from tri-metal layers of copper-aluminium-copper being copper circuit patterns present on opposing surfaces of an aluminium foil, one of the copper patterns being laminated onto a substrate, the etchant comprising an aqueous solution of: (1) 60 to 500 g/l base selected from (a) sodium hydroxide, (b) potassium hydroxide, and (c) their mixture; and (2) 70 to 500 g/l of a nitrate salt.
Abstract:
An etchant useful for chemically milling aluminium from tri-metal layers of copper-aluminium-copper being copper circuit patterns present on opposing surfaces of an aluminium foil, one of the copper patterns being laminated onto a substrate, the etchant comprising an aqueous solution of: (1) 60 to 500 g/l base selected from (a) sodium hydroxide, (b) potassium hydroxide, and (c) their mixture; and (2) 30 to 500 g/l of a nitrite salt, borate salt, a bromate salt, or a mixture of any of them.
Abstract:
A wiring board is fabricated through the following steps: (A) forming, on one side of an elongated carrier metal foil made of a first metal, a thin layer with a second metal whose etching conditions are different from those of the first metal; (B) forming, on a surface of the thin layer, a desired wiring pattern with a third metal whose etching conditions are different from those of the second metal; (C) superposing the carrier metal foil on an insulating substrate with the side of the wiring pattern being positioned inside, whereby the wiring pattern is embedded in the insulating substrate; and (D) etching off the carrier metal foil and the thin layer at desired parts thereof.