The invention provides a new method and chip scale package is provided.
The inventions starts with a substrate over which a contact point is
provided, the contact point is exposed through an opening created in the
layer of passivation and a layer of polymer or elastomer. A barrier/seed
layer is deposited, a first photoresist mask is created exposing the
barrier/seed layer where this layer overlies the contact pad and,
contiguous therewith, over a surface area that is adjacent to the contact
pad and emanating in one direction from the contact pad. The exposed
surface of the barrier/seed layer is electroplated for the creation of
interconnect traces. The first photoresist mask is removed from the
surface of the barrier/seed layer. A second photoresist mask, defining
the solder bump, is created exposing the surface area of the barrier/seed
layer that is adjacent to the contact pad and emanating in one direction
from the contact pad. The solder bump is created in accordance with the
second photoresist mask, the second photoresist mask is removed from the
surface of the barrier/seed layer, exposing the electroplating and the
barrier/seed layer with the metal plating overlying the barrier/seed
layer. The exposed barrier/seed layer is etched in accordance with the
pattern formed by the electroplating, reflow of the solder bump is
optionally performed.