Method for forming copper bump antioxidation surface
AssigneeAptos Corporation
InventorKuo Lung Lei
Life of this patent
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Abstract
A method for forming a copper bump for flip chip bonding having improved oxidation resistance and thermal stability including providing a copper column having a thickness of at least about 40 microns overlying a metallurgy including an uppermost copper metal layer and a lowermost titanium layer the lowermost titanium layer in contact with an exposed copper bonding pad portion surrounded by a passivation layer; and, selectively depositing at least one protective metal layer over the copper column according to an electrolytic deposition process.
Claims12
A method for forming a copper bump having improved oxidation resistance and thermal stability comprising the steps of:
- providing a metal bonding pad formed over a substrate comprising electrical communication pathways;
- forming a passivation layer over the substrate excepting an exposed portion of the metal bonding pad;
- forming a first metallurgy over the passivation layer and contacting the exposed portion;
- forming a second metallurgy overlying and contacting the first metallurgy;
- forming a patterned photoresist layer over the second metallurgy patterned to provide an opening aligned to overlie the exposed portion;
- depositing a copper layer to at least partially fill the opening to form a copper bump;
- removing the patterned photoresist layer to expose the copper bump;
- selectively depositing at least one oxidation resistant metal layer over the copper bump to cover exposed portions comprising upper and sidewall portions according to an electro-chemical deposition (ECD) process;
- and
- etcthing through a thickness of the first metallurgy surounding the copper bump to expose the passivation layer following the step of selectively depositing.
Dependencies are inferred from the claim text.