Method to improve selectivity cobalt cap process

摘要

Methods of forming a Co cap on a Cu interconnect in or through an ULK ILD with improved selectivity while protecting an ULK ILD surface are provided. Embodiments include providing a Cu filled via in an ULK ILD; depositing a Co precursor and H2 over the Cu-filled via and the ULK ILD, the Co precursor and H2 forming a Co cap over the Cu-filled via; depositing an UV cured methyl over the Co cap and the ULK ILD; performing an NH3 plasma treatment after depositing the UV cured methyl; and repeating the steps of depositing a Co precursor through performing an NH3 plasma treatment to remove impurities from the Co cap.

主权项

1. A method comprising:
providing a copper (Cu) filled via in an ultra low-k (ULK) interlayer dielectric (ILD); depositing a cobalt (Co) precursor and hydrogen (H2) over the Cu-filled via and the ULK ILD, the Co precursor and H2 forming a Co cap over the Cu-filled via; depositing an ultraviolet (UV) cured methyl over the Co cap and the ULK ILD; performing an ammonia (NH3) plasma treatment after depositing the UV cured methyl; and repeating the steps of depositing a Co precursor through performing an NH3 plasma treatment to remove impurities from the Co cap.