Composite copper foil, process for preparing the same, and copper-clad laminate and printed wiring board using the same

摘要

This invention provides a composite foil (1) comprising an organic release layer (3) between a metal carrier layer (2) and an ultra-thin copper foil (4), and a process for producing such composite foils comprising the steps of depositing the organic release layer (3) on the metal carrier layer (2) and then forming an ultra-thin copper foil layer (4) on said organic release layer (3) by electrodeposition. The organic release layer (3) preferably is a nitrogen-containing compound, a sulfur-containing compound, or a carboxylic acid, which provides a uniform bond strength which is adequate to prevent separation of the carrier (2) and ultra-thin copper foil (4) during handling and lamination, but which is significantly lower than the peel strength of a copper/substrate bond, so that the carrier (2) can easily be removed after lamination of the composite foil (1) to an insulating substrate (6). The invention also includes laminates (5) made from such composite foils (1) and printed wiring boards (7) made from such laminates.