Through via structure for step coverage improvement

A semiconductor device, comprising:

• a substrate;
• a first dielectric layer disposed over the substrate;
• a dielectric structure disposed on the first dielectric layer;
• a second dielectric layer disposed on the dielectric structure, wherein a through via hole passes through the second dielectric layer, the dielectric structure, and the first dielectric layer, the through via hole comprises a bottom and a sidewall adjacent to the bottom, and the sidewall of the through via hole comprises at least one indentation structure in the dielectric structure, wherein the at least one indentation structure has a substantially C-shaped cross-section, and the at least one indentation structure has a first surface, a second surface, and a tilted surface connecting the first surface and the second surface;
• a barrier layer covering the sidewall and the bottom of the through via hole;
• a glue layer covering the barrier layer;
• a copper seed layer covering the glue layer;
• and
• a copper layer covering the copper seed layer and filling the through via hole.

A semiconductor device, comprising:

• a substrate;
• a dielectric structure disposed over the substrate, wherein the dielectric structure comprises a first dielectric film, a second dielectric film, and a third dielectric film stacked in sequence, the dielectric structure has a through via hole passing through the dielectric structure, the through via hole comprises a bottom and a sidewall adjacent to the bottom, and the sidewall of the through via hole comprises a first indentation structure in the second dielectric film, wherein the first indentation structure has a substantially C-shaped cross-section, and the first indentation structure has a first surface, a second surface, and a tilted surface connecting the first surface and the second surface;
• a barrier layer covering the sidewall and the bottom of the through via hole;
• a glue layer covering the barrier layer;
• a copper seed layer covering the glue layer;
• and
• a copper layer covering the copper seed layer and filling the through via hole.