Multi-layer passivation structure and method

A method, comprising:

• forming a top metal (TM) contact over a semiconductor substrate;
• depositing a first dielectric layer over the TM contact;
• forming a metal-insulator-metal (MIM) structure over the first dielectric layer;
• depositing a second dielectric layer over the MIM structure;
• forming an opening in the first dielectric layer and the second dielectric layer to expose the TM contact;
• depositing a metal layer over the second dielectric layer and in the opening;
• after the depositing of the metal layer, patterning the metal layer to form a contact feature that is electrically coupled to the MIM structure and to the TM contact, the contact feature comprising a metal via in the opening and an upper portion over a top surface of the second dielectric layer;
• after the patterning of the metal layer, forming a passivation structure over the contact feature and the second dielectric layer, wherein forming the passivation structure comprises:
• depositing a first silicon nitride (SiN) layer over the contact feature and the second dielectric layer;
• depositing an oxide layer over the first SiN layer;
• and
• depositing a second SiN layer over the oxide layer;
• and
• forming a bonding pad that is electrically coupled to the contact feature.

A method, comprising:

• forming a metal contact over a semiconductor substrate;
• forming a first passivation structure over the metal contact;
• forming an opening through the first passivation structure to expose the metal contact;
• forming a contact feature over the opening, wherein a lower portion of the contact feature extends through the first passivation structure and an upper portion of the contact feature is above and in direct contact with a top surface of the first passivation structure, wherein a width of a top surface of the upper portion is smaller than a width of a bottom surface of the upper portion, wherein the upper portion comprises a taper footing profile to reduce stress concentrated at corners of the contact feature;
• and
• after the forming of the contact feature, forming a second passivation structure over the contact feature and the first passivation structure, wherein the second passivation structure comprises a first silicon nitride layer, a silicon oxide layer over the first silicon nitride layer, and a second silicon nitride layer over the silicon oxide layer.