Method of forming opening in passivation layer and structures thereof

A method, comprising:

• forming a contact pad electrically coupled to an underlying multi-layer interconnect (MLI) structure by a contact via;
• depositing an oxide layer over the contact pad, a nitride layer over the oxide layer, and a polyimide (PI) layer over the nitride layer;
• and
• forming a via opening that penetrates through the PI layer, the nitride layer, and the oxide layer and exposes a top surface of the contact pad;
• wherein the forming the via opening includes patterning the PI layer to expose sidewalls of the PI layer and a portion of the nitride layer, and after patterning the PI layer, etching through the nitride layer and the oxide layer to expose sidewalls of the nitride layer, sidewalls of the oxide layer, and the top surface of the contact pad while simultaneously laterally etching the exposed sidewalls of the PI layer to recess the sidewalls of the PI layer from the sidewalls of the nitride layer and expose corners of the etched nitride layer;
• and
• wherein the via opening includes an upper portion having a first width and a lower portion having a second width less than the first width.

A device, comprising:

• a patterned passivation layer disposed over a contact pad;
• a patterned polyimide (PI) layer disposed over the patterned passivation layer, wherein the patterned passivation layer defines a lower portion of a via opening that penetrates through the patterned PI layer and the patterned passivation layer, and wherein the patterned PI layer defines an upper portion of the via opening;
• and
• a metal layer formed within the via opening and in contact with a top surface of the contact pad;
• wherein a bottommost part of a first sidewall surface of the upper portion of the via opening is recessed from corners defined at a topmost part of a second sidewall surface of the lower portion of the via opening;
• and
• wherein the upper portion of the via opening has a first width that tapers, wherein the lower portion of the via opening has a second width that tapers, and wherein the first width at the bottommost part of the upper portion is greater than the second width at the topmost part of the lower portion.