Method of forming low stress multi-layer metallurgical structures and high reliable lead free solder termination electrodes

A method for manufacturing a bond pad structure, the method comprising:

• providing a substrate;
• forming at least one metal pad over the substrate;
• forming a passivation layer over the substrate having an opening to expose a portion of the at least one metal pad;
• removing an oxidized layer on the metal pad using a radio frequency (rf) sputtering etch method;
• depositing an adhesion layer at least over the exposed portion of the at least one metal pad;
• depositing a wetting and conducting layer over the adhesion layer;
• depositing a photoresist layer over the substrate;
• forming trench in the photoresist layer directly over the exposed portion of the metal pad using a mask, a perimeter of the trench defining an area parallel to the at least one metal pad;
• removing a photoresist residue in the trench using a plasma descum etch process;
• electroplating a copper layer in the trench over the wetting and conducting layer;
• electroplating a barrier layer in trench over the copper layer;
• electroplating a termination electrode in the trench over the barrier layer, the termination electrode comprising tin;
• removing the photoresist layer;
• etching to remove the wetting and conducting layer disposed outside an area;
• etching to remove the adhesion layer disposed outside the area;
• and
• reflowing the termination electrode,
• wherein the barrier layer prevents formation of an intermetallic compound in proximity to the copper layer by precluding diffusion of tin from the termination electrode to the copper layer.

An integrated circuit device comprising:

• a substrate;
• at least one metal pad formed on the substrate;
• a passivation layer having an opening formed around the at least one metal pad;
• a multilayered under bump metallurgy structure coupled to the at least one metal pad, the under bump metallurgy structure comprising:
• a first PVD thin film comprising chromium;
• a second PVD thin film comprising copper overlying the first PVD thin film;
• a plated first layer comprising copper overlying the second PVD thin film;
• and
• a plated second layer comprising nickel overlying the plated first layer;
• and
• a termination electrode coupled to the under bump metallurgy structure, the termination electrode includes tin,
• wherein the plated second layer prevents formation of an intermetallic compound in proximity to the plated first layer by precluding diffusion of tin from the termination electrode to the plated first layer.