Spin-on-glass planarization process with ion implantation

DETAILED DESCRIPTION A principal object of the present invention is to provide an effective and manufacturable method for planarizing an integrated circuit surface with a spin-on-glass sandwich layer, where the entire surface area of spin-on-glass exposed within a via etched through the spin-on-glass sandwich layer is not susceptible to sorption and outgassing of moisture.
Another object of the present invention is to provide an efficient method of planarizing an integrated circuit surface which does not result in metallurgy and high resistivity problems associated with metallic interconnections through vias etched through the planarizing layer.
In accord with the objects of this invention, a new method of planarizing an integrated circuit is described.
The dielectric layers between the conductive layers of an integrated circuit are formed and planarized through a spin-on-glass sandwich process.
In this new spin-on-glass sandwich process, a conformal first silicon oxide layer is deposited over a metal layer.
This oxide layer is covered with a spin-on-glass layer which is subsequently fully cured at elevated temperature.
Ions are then implanted into and through the spin-on-glass layer using one of the following three conditions: (1) Silicon, Argon or Phosphorus implantation ions; 5E13 to 1E15 ions/cm2 implantation dose; 150 to 400 keV implantation energy; (2) Boron, Oxygen, Nitrogen or Fluorine implantation ions; 1E15 to 5E16 ions/cm2 implantation dose; 50 to 200 keV implantation energy; or (3) Arsenic implantation ions; 2E13 to 5E14 ions/cm2 implantation dose; 300 to 800 keV implantation energy.
A second conformal silicon oxide layer is deposited thereover to form the Completed spin-on-glass sandwich layer.
Via openings can now be made through the spin-on-glass sandwich layer and filled with metal.
Planarity of the process is excellent, and the via surfaces are not susceptible to moisture sorption, the outgassing of which during via metallization processing may corrode the metal within the via and cause high via resistance