Semiconductor structures and methods of forming the same

A semiconductor structure, comprising:

• a first conductive pad having a first portion extending into a dielectric structure and a second portion over the first portion;
• a second conductive pad over the dielectric structure, wherein a thickness of the second conductive pad is greater than a thickness of the second portion of the first conductive pad;
• a first dielectric layer over the first and second conductive pads and having a non-planar top surface, wherein a thickness of a first portion of the first dielectric layer directly over the first conductive pad is substantially equal to a thickness of a second portion of the first dielectric layer directly over the second conductive pad;
• an etch stop layer over the first dielectric layer;
• a second dielectric layer over the etch stop layer, wherein a thickness of a first portion of the second dielectric layer directly over the first conductive pad is greater than a thickness of a second portion of the second dielectric layer directly over the second conductive pad;
• a first bonding structure extending through the first and second dielectric layers and the etch stop layer and configured to electrically couple to the first conductive pad;
• and
• a second bonding structure extending through the first and second dielectric layers and the etch stop layer and configured to electrically couple to the second conductive pad.

A semiconductor structure, comprising:

• a first conductive feature formed over a substrate;
• a second conductive feature formed over the substrate, and a topmost point of a top surface of the second conductive feature is above a topmost point of a top surface of the first conductive feature;
• a first conformal dielectric layer over the first conductive feature and the second conductive feature;
• a conformal oxide layer over the first conformal dielectric layer, wherein the conformal oxide layer comprises a first portion disposed directly over the first conductive feature and a second portion disposed directly over the second conductive feature, wherein a thickness of the first portion is substantially equal to a thickness of the second portion;
• a second conformal dielectric layer on the conformal oxide layer, wherein the second conformal dielectric layer comprises a non-planar top surface;
• a multi-layer dielectric structure on the second conformal dielectric layer and having a substantially planar top surface;
• a first bonding structure on and electrically coupled to the first conductive feature;
• and
• a second bonding structure on and electrically coupled to the second conductive feature.