Method for forming a patterned layer on a substrate

A method of forming a pattern of conductive material on a dielectric material with a plurality of access openings through said dielectric material communicating with the conductive material comprising the steps of:

• providing a sheet of conductive material which is to be patterned;
• providing a layer of a first photoimageable material on one face of said conductive material;
• providing a layer of a second photoimageable material on the other face of said conductive material;
• said layer of said first photoimageable material being a dielectric film forming material;
• the material of one of said layers of material being developable by a developer which will not develop the other layer of said material;
• imagewise patterning said first and second layers of photoimageable material, said layer of said second photoimageable material being imaged in the pattern to be formed in said conductive material, said layer of said first photoimageable material being imaged in the pattern of the through openings to be formed in the first photoimageable material;
• developing said layer of the second photoimageable material to reveal the underlying conductive material;
• developing said layer of the first photoimageable material to form openings through said layer of first photoimageable material;
• said process being further characterized by etching the conductive material revealed upon developing of said layer of said second photoimageable material with an etch media that will not substantially alter said layer of said first photoimageable material, said etching taking place before the layer of first photoimageable material is developed;
• whereby a pattern of conducting material is formed on a dielectric material with openings extending through said dielectric material to said patterned conductive material;
• and thereafter providing electrically conducting material in said access openings to thereby form discrete conductors in said access openings communicating with said pattern of conductive material.