Abstract: A method of producing a multilayer system comprising the steps of:1. adhering a continuous cohesive pattern of electrically conductive oxidizable material (e.g. copper) to an electrically insulating surface of a substrate,2. coating the pattern and the parts of the substrate surface not adhering to the pattern with a firable dielectric which is fusable at 500.degree.-600.degree. C.,3. firing the dielectric to 500.degree.-600.degree. C. to cause fusion of the dielectric, whereby an oxide-fused dielectric bond is formed. Also multilayers having the features of the products of this method.

Abstract: A method of producing a multilayer system comprising the steps of:1. adhering a continuous cohesive pattern of electrically conductive oxidisable material (e.g. copper) to an electrically insulating surface of a substrate,2. coating the pattern and the parts of the substrate surface not adhering to the pattern with a firable dielectric which is fusable at 500.degree.-600.degree. C.,3. firing the dielectric to 500.degree.-600.degree. C. to cause fusion of the dielectric, whereby an oxide-fused dielectric bond is formed. Also multilayers having the features of the products of this method.

Abstract: A multilayer system comprises a seed layer (4) of copper deposited on an electrically insulating substrate (2). The seed layer (4) carries a copper pattern (8). An air fired dielectric (10) encapsulates the pattern (8) and the exposed parts of the seed layer (4). The outer skin of the pattern is oxidized as is also the whole of the seed layer other than where it underlies the copper pattern. The oxidized regions of the copper both form a firm bond with the dielectric and inhibit the migration of oxygen into the inner regions of the conductor pattern (8). Also the oxidation of the seed layer renders it non-conductive and therefore obviates the need for its removal. Through holes (12) produced in the dielectric enable electrical connection to the pattern (8).

Abstract: A method of producing a multilayer system comprises depositing a seed layer (4) of copper on an electrically insulating substrate (2). A resist is formed on the copper seed layer (4), and the seed layer is electroplated with copper to produce a desired conductor pattern (8). An air firing dielectric (10) is screen printed over the pattern (8) and the exposed parts of the seed layer (4) are fired in air. The outer skin of the pattern is oxidized as is also the whole of the seed layer other than where it underlies the copper pattern. The ozidized regions of the copper both form a firm bond with the dielectric and inhibit the migration of oxygen into the inner regions of the conductor pattern (8). Also the oxidation of the seed layer renders it non-conductive and therefore obviates the need for its removal. Through holes (12) produced in the dielectric enable electrical connection to the pattern (8).

Abstract: A method of forming an electrically conductive pattern on a substrate includes the steps of forming a layer of gold on an electrically insulating substrate and coating the gold layer with a photo-resist. The resist is exposed to light through a photo mask and the exposed portions of the photo-resist are selectively removed by etching. The now exposed parts of the gold layer are coated with copper and the remaining photo-resist is removed. The exposed parts of the gold layer and the copper are subjected to molten tin which simultaneously acts to dissolve the exposed parts of the gold layer and to form an electrically conductive coating on the copper.The process enables the formation of a precise conductive pattern with enhanced reliability.