Low cost high density thin film processing

A method for building a high density thin film interconnect structure, comprising the steps of:

• depositing a first layer of dielectric over a substrate;
• creating a via pattern in the dielectric layer if needed;
• applying a swell and etch process to the surface of said first layer of dielectric;
• depositing an interconnect plating base by electroless seeding of Cu;
• depositing a layer of photoresist over the surface of said deposited layer of interconnect plating base;
• masking and patterning said layer of photoresist in the reverse pattern of the interconnect lines for additive plating of the interconnect structure thereby creating a photoresist plating mask;
• depositing additive plating of the interconnect structure by depositing Cu;
• removing said photoresist plating mask that has been used for said additive plating of said interconnect structure;
• wet etching to remove the interconnect plating base from between said interconnect structure said wet etching using micro-etch processes of the printed circuit board technology;
• coating the created interconnect structure with a dielectric;
• and
• creating vias in the dielectric for connections to an overlying metal layer said creating vias using photo-imaging and developing methods applied to photo-sensitive dielectric or by using laser ablation process of the printed circuit board technology.