Semiconductor structure and manufacturing method thereof

A semiconductor structure, comprising:

• a conductive layer comprising a first lateral side, a second lateral side and a middle portion between the first lateral side and the second lateral side, the conductive layer comprising a same material across the first lateral side, the middle portion and the second lateral side;
• an etch-resistant layer disposed above the conductive layer;
• a dielectric layer surrounding the conductive layer and the etch-resistant layer, the conductive layer comprising an upper surface defined by sidewalls of the dielectric layer;
• and
• a spacer surrounding the conductive layer and the etch-resistant layer,
• wherein the middle portion is thicker than the first lateral side or the second lateral side, and a thickness of the conductive layer continually decreases from the middle portion to the first lateral side or the second lateral side.

A semiconductor structure, comprising:

• a first dielectric layer disposed over a substrate;
• a second dielectric layer disposed over the first dielectric layer and comprising a bottom portion and a sidewall over the bottom portion;
• a conductive layer disposed above the second dielectric layer, the conductive layer covering an entirety of the bottom portion of the second dielectric layer;
• a protection layer over the conductive layer, the conductive layer separating the protection layer from the bottom portion of the second dielectric layer;
• and
• a spacer disposed over the substrate and laterally surrounding the first dielectric layer, the second dielectric layer, the conductive layer and the protection layer,
• wherein the conductive layer comprises a first lateral side facing the second dielectric layer, a second lateral side facing the second dielectric layer, and a central portion between the first lateral side and the second lateral side of the conductive layer, wherein the conductive layer comprises a same material with respect to an etchant across the first lateral side, the central portion and the second lateral side, and a first thickness of the central portion is greater than a second thickness of one of the first lateral side and the second lateral side, wherein the conductive layer has a third thickness continually decreasing from the central portion to the first lateral side or the second lateral side, and
• wherein the protection layer comprises a third lateral side aligned with the first lateral side of the conductive layer and a fourth lateral side aligned with the second lateral side of the conductive layer, and a thickness sum of the conductive layer and the protection layer at the first lateral side and the third lateral side is substantially equal to a thickness sum of the conductive layer and the protection layer at the second lateral side and the fourth lateral side.