Metallization stack structure to improve electromigration resistance and keep low resistivity of ULSI interconnects

摘要

There is provided an improved metallization stack structure so as to produce a higher electromigration resistance and yet maintain a relatively low resistivity. The metallization stack structure includes a pure copper layer sandwiched between a top thin doped copper layer and a bottom thin doped copper layer. The top and bottom thin doped copper layers produce a higher electromigration resistance. The pure copper layer produces a relatively low resistivity.