Patent ID: 6740577
Filing Date: 2004-05-25
Classification: H01L

Abstract:
A method for the creation of a torch bump, comprising the steps of:providing a substrate, said substrate having been provided with a contact pad, a patterned layer of passivation having been deposited over the substrate, a surface of said contact pad being exposed through said patterned layer of passivation, a layer of Under-Bump-Metallurgy (UBM) having been blanket deposited over the layer of passivation including the exposed surface of the contact pad; creating a base of said torch bump of first successive layers of metal overlying said contact pad using a patterned first layer of dry film as a mask, said first successive layers of metal comprising: (i) a first layer of copper deposited over the exposed surface of said layer of UBM; (ii) a second layer of nickel deposited over said first layer of copper; and (iii) a third layer of gold deposited over said second layer of nickel then forming a patterned second layer of dry film over said patterned first layer of dry film to expose said base; creating a layer of solder of said torch bump overlying said base using said patterned second layer of dry film as a mask; removing said patterned first and second layers of dry film; and applying reflow to said layer of solder.