Semiconductor die including diffusion barrier layers embedding bonding pads and methods of forming the same

A structure comprising a first semiconductor die, wherein the first semiconductor die comprises:

• first semiconductor devices located over a first substrate;
• first interconnect-level dielectric material layers embedding first metal interconnect structures that are electrically connected to the first semiconductor devices and overlie the first semiconductor devices;
• a layer stack of a first pad-connection-via-level dielectric material layer and a first proximal dielectric diffusion barrier layer overlying the first interconnect-level dielectric material layers and embedding first pad-connection via structures;
• and
• a first pad-level dielectric material layer including first pad cavities that are filled with a respective combination of a first bonding pad and a respective first dielectric diffusion barrier portion, wherein each of the first bonding pads contacts a respective subset of the first pad-connection via structures;
• wherein each of the first dielectric diffusion barrier portions comprises sidewall segments in contact with the first pad-level dielectric material layer and extending from a bottom surface of the first pad-level dielectric material layer to a top surface of the first pad-level dielectric material layer;
• and
• wherein each of the first dielectric diffusion barrier portions further comprises a horizontal segment having a bottom surface that contacts the first proximal dielectric diffusion barrier layer, wherein the bottom surface comprises an outer periphery that is adjoined to bottom edges of the sidewall segments and an inner periphery that is laterally offset inward from the outer periphery by an offset distance that is greater than a thickness of the sidewall segments of the first dielectric diffusion barrier portions.