A method for forming a semiconductor structure includes following operations. A first substrate including a first side, a second side opposite to the first side, and a metallic pad disposed over the first side is received. A dielectric structure including a first trench directly above the metallic pad is formed. A second trench is formed in the dielectric structure and a portion of the first substrate. A sacrificial layer is formed to fill the first trench and the second trench. A third trench is formed directly above the metallic pad. A barrier ring and a bonding structure are formed in the third trench. A bonding layer is disposed to bond the first substrate to a second substrate. A portion of the second side of the first substrate is removed to expose the sacrificial layer. The sacrificial layer is removed by an etchant.

A method for forming a semiconductor structure includes following operations. A first substrate including a first side, a second side opposite to the first side, and a metallic pad disposed over the first side is received. A dielectric structure including a first trench directly above the metallic pad is formed. A second trench is formed in the dielectric structure and a portion of the first substrate. A sacrificial layer is formed to fill the first trench and the second trench. A third trench is formed directly above the metallic pad. A barrier ring and a bonding structure are formed in the third trench. A bonding layer is disposed to bond the first substrate to a second substrate. A portion of the second side of the first substrate is removed to expose the sacrificial layer. The sacrificial layer is removed by an etchant.

A method for forming a semiconductor structure includes following operations. A first substrate including a first side, a second side opposite to the first side, and a metallic pad disposed over the first side is received. A dielectric structure including a first trench directly above the metallic pad is formed. A second trench is formed in the dielectric structure and a portion of the first substrate. A sacrificial layer is formed to fill the first trench and the second trench. A third trench is formed directly above the metallic pad. A barrier ring and a bonding structure are formed in the third trench. A bonding layer is disposed to bond the first substrate to a second substrate. A portion of the second side of the first substrate is removed to expose the sacrificial layer. The sacrificial layer is removed by an etchant.

A method for forming a semiconductor structure includes following operations. A first substrate including a first side, a second side opposite to the first side, and a metallic pad disposed over the first side is received. A dielectric structure including a first trench directly above the metallic pad is formed. A second trench is formed in the dielectric structure and a portion of the first substrate. A sacrificial layer is formed to fill the first trench and the second trench. A third trench is formed directly above the metallic pad. A barrier ring and a bonding structure are formed in the third trench. A bonding layer is disposed to bond the first substrate to a second substrate. A portion of the second side of the first substrate is removed to expose the sacrificial layer. The sacrificial layer is removed by an etchant.

A semiconductor structure includes a first substrate, a metallic pad disposed over the first substrate, a dielectric structure disposed over the first substrate and exposing a portion of the metallic pad, a bonding structure disposed over and electrically connected to the metallic pad, a barrier ring surrounding the bonding structure, and a through-hole penetrating the first substrate and the dielectric structure. The bonding structure includes a bottom and a sidewall, the bottom of the bonding structure is in contact with the metallic pad, a first portion of the sidewall of the bonding structure is in contact with the dielectric structure, and a second portion of the sidewall of the bonding structure is in contact with the barrier ring.

A semiconductor structure includes a first substrate, a metallic pad disposed over the first substrate, a dielectric structure disposed over the first substrate and exposing a portion of the metallic pad, a bonding structure disposed over and electrically connected to the metallic pad, a barrier ring surrounding the bonding structure, and a through-hole penetrating the first substrate and the dielectric structure. The bonding structure includes a bottom and a sidewall, the bottom of the bonding structure is in contact with the metallic pad, a first portion of the sidewall of the bonding structure is in contact with the dielectric structure, and a second portion of the sidewall of the bonding structure is in contact with the barrier ring.

A semiconductor structure includes a first substrate, a metallic pad disposed over the first substrate, a dielectric structure disposed over the first substrate and exposing a portion of the metallic pad, a bonding structure disposed over and electrically connected to the metallic pad, a barrier ring surrounding the bonding structure, and a through-hole penetrating the first substrate and the dielectric structure. The bonding structure includes a bottom and a sidewall, the bottom of the bonding structure is in contact with the metallic pad, a first portion of the sidewall of the bonding structure is in contact with the dielectric structure, and a second portion of the sidewall of the bonding structure is in contact with the barrier ring.

A semiconductor structure includes a first substrate, a metallic pad disposed over the first substrate, a dielectric structure disposed over the first substrate and exposing a portion of the metallic pad, a bonding structure disposed over and electrically connected to the metallic pad, a barrier ring surrounding the bonding structure, and a through-hole penetrating the first substrate and the dielectric structure. The bonding structure includes a bottom and a sidewall, the bottom of the bonding structure is in contact with the metallic pad, a first portion of the sidewall of the bonding structure is in contact with the dielectric structure, and a second portion of the sidewall of the bonding structure is in contact with the barrier ring.