Abstract: A continuous process for forming multilayer circuit structures which includes applying and curing a film forming polymer onto the matte side of a copper foil. The opposite (shiny) side of the foil is optionally but preferably cleaned, and applied with a photoresist which is then optionally but preferably dried. The photoresist is exposed, and developed to remove the nonimage areas but leave the image areas. The foil under the removed nonimage area is then etched to form a copper pattern, and the remaining photoresist is optionally but preferably removed. The foil is then cut into sections, and then optionally but preferably punched with registration holes. The copper pattern is then optionally but preferably treated with a bond enhancing treatment, optionally but preferably inspected for defects, and laminated onto a substrate to form a multilayered circuit structure.

Abstract: This invention relates to printed circuit boards having improved fire resistance and improved environmental stability. The invention provides halogen-free fire retardant printed circuit boards incorporating potentially flammable polymers. Flame resistant thermoplastic layers prevent combustion of thermosetting polymers, as well as adding strength to the laminate, resulting in a less brittle thin core than the prior art. The flame resistant circuit board is cost efficient, environmentally safe and has excellent properties, including a decreased probability of shorting, good dielectric breakdown voltage, a smooth surface and good electrical/thermal performance.

Abstract: A continuous process for forming multilayer circuit structures which includes applying and curing a film forming polymer onto the matte side of a copper foil. The opposite (shiny) side of the foil is optionally but preferably cleaned, and applied with a photoresist which is then optionally but preferably dried. The photoresist is exposed, and developed to remove the nonimage areas but leave the image areas. The foil under the removed nonimage area is then etched to form a copper pattern, and the remaining photoresist is optionally but preferably removed. The foil is then cut into sections, and then optionally but preferably punched with registration holes. The copper pattern is then optionally but preferably treated with a bond enhancing treatment, optionally but preferably inspected for defects, and laminated onto a substrate to form a multilayered circuit structure.