Self-Aligned Passivation Process for Non-Self-Passivating Conductors
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
A method is described for passivating conductive refractory metal lines, e.g., molybdenum with insulating materials, such as silicon nitride (Si3N4). The lines are passivated using a self-aligned technique that does not rely on thermal oxidation. As shown in the figure, a silicon substrate 2 is overlaid with a thin insulating film 4, e.g., Si3N4 . A blanket layer of a non-self-passivating conductor M is deposited, followed by deposition of a layer 6 of Si3N4 . The insulator 6 and the conductor M are then photo patterned and anisotropically etched to form conductive lines, and the photoresist is then stripped. This standard set of process steps results in the rectangular cross-section of conductive line M having insulator on its upper surface. Note that the vertical sidewalls of the conductor M are unprotected.