Deep trench capacitor including a compact contact region and methods of forming the same

A bonded assembly comprising a first semiconductor die and a second semiconductor die, wherein:

• the first semiconductor die comprises a semiconductor substrate and a deep trench capacitor embedded within the semiconductor substrate;
• the deep trench capacitor comprises:
• a first deep trench and a second deep trench each extending downward from a top surface of a substrate that is located within a first horizontal plane;
• a layer stack including at least three metallic electrode layers interlaced with at least two node dielectric layers, wherein each layer within the layer stack continuously extends over the top surface of the substrate and into each of the first deep trench and the second deep trench, wherein the at least three metallic electrode layers comprise a first metallic electrode layer, a second metallic electrode layer, and a third metallic electrode layer in an order of proximity from the substrate, wherein a topmost surface of the layer stack is located entirely within a second horizontal plane that overlies the first horizontal plane;
• a dielectric fill material layer comprising:
• a first horizontally-extending portion that is located within an area of an outer periphery of the topmost surface of the layer stack and is located entirely above the second horizontal plane and laterally extends over entire areas of the first deep trench and the second deep trench;
• a first vertically-extending portion that vertically extends from the horizontally-extending portion into a central volume of the first deep trench;
• a second vertically-extending portion that vertically extends from the horizontally-extending portion into a central volume of the second deep trench;
• and
• a second horizontally-extending portion that is located outside a region in which the layer stack is present and vertically recessed relative to the first horizontally-extending portion,
• wherein the topmost surface of the layer stack comprises a surface segment which laterally extends between, and is laterally bounded by, a top edge of the first vertically-extending portion of the dielectric fill material layer and a top edge of the second vertically-extending portion of the dielectric fill material layer and located entirely within the second horizontal plane,
• wherein an entirety of the surface segment of the topmost surface of the layer stack is in contact with the first horizontally-extending portion of the dielectric fill material layer within the second horizontal plane;
• a contact-level dielectric layer overlying the substrate, the layer stack, and the dielectric fill material layer and having a horizontal top surface that extends over the first horizontally-extending portion and the second horizontally-extending portion of the dielectric fill material layer;
• a first contact assembly vertically extending through the contact-level dielectric layer and the first horizontally-extending portion of the dielectric fill material layer, located entirely within an area of said surface segment of the topmost surface of the layer stack, and including a first tubular insulating spacer laterally surrounding a first contact via structure that contacts a horizontal surface of the first metallic electrode layer, wherein the first tubular insulating spacer contacts a first cylindrical sidewall of the first horizontally-extending portion of the dielectric fill material layer, a first cylindrical sidewall of the second metallic electrode layer, and a first cylindrical sidewall of the third metallic electrode layer;
• a second contact assembly vertically extending through the contact-level dielectric layer and the first horizontally-extending portion of the dielectric fill material layer, located entirely within the area of said surface segment of the topmost surface of the layer stack, and including a second tubular insulating spacer laterally surrounding a second contact via structure that contacts a horizontal surface of the third metallic electrode layer, wherein the second tubular insulating spacer contacts a second cylindrical sidewall of the first horizontally-extending portion of the dielectric fill material layer;
• and
• a first metal pad structure comprising a bottom surface that contacts a top surface of the first contact via structure and a top surface of the second contact via structure;
• and
• the second semiconductor die is bonded to the first semiconductor die and comprises semiconductor devices therein, wherein the deep trench capacitor is electrically connected to the semiconductor devices through bonding pads or solder material portions.

A deep trench capacitor comprising:

• a plurality of deep trenches extending downward from a top surface of a substrate that is located within a first horizontal plane and comprising groups of first-type deep trenches each having a greater first lateral extent along a first horizontal direction than along a second horizontal direction, and further comprising groups of second-type deep trenches each having a greater second lateral extent along the second horizontal direction than along the first horizontal direction, wherein the plurality of deep trenches comprises a neighboring pair of deep trenches that includes a first deep trench and a second deep trench without any intervening deep trench therebetween;
• a layer stack including at least three metallic electrode layers interlaced with at least two node dielectric layers, wherein each layer within the layer stack continuously extends over the top surface of the substrate and into each of the first-type deep trench and the second-type deep trench, wherein the at least three metallic electrode layers comprise a first metallic electrode layer, a second metallic electrode layer, and a third metallic electrode layer in an order of proximity from the substrate, wherein a topmost surface of the layer stack is located entirely within a second horizontal plane that overlies the first horizontal plane;
• a dielectric fill material layer comprising:
• a first horizontally-extending portion that is located within an area of an outer periphery of the topmost surface of the layer stack and is located entirely above the second horizontal plane and laterally extends over entire areas of the first deep trench and the second deep trench;
• a first vertically-extending portion that vertically extends from the horizontally-extending portion into a central volume of the first deep trench;
• a second vertically-extending portion that vertically extends from the horizontally-extending portion into a central volume of the second deep trench;
• and
• a second horizontally-extending portion that is located outside a region in which the layer stack is present and vertically recessed relative to the first horizontally-extending portion,
• wherein the topmost surface of the layer stack comprises a surface segment which laterally extends between, and is laterally bounded by, a top edge of the first vertically-extending portion of the dielectric fill material layer and a top edge of the second vertically-extending portion of the dielectric fill material layer and located entirely within the second horizontal plane,
• wherein an entirety of the surface segment of the topmost surface of the layer stack is in contact with the first horizontally-extending portion of the dielectric fill material layer within the second horizontal plane;
• a contact-level dielectric layer overlying the substrate, the layer stack, and the dielectric fill material layer and having a horizontal top surface that extends over the first horizontally-extending portion and the second horizontally-extending portion of the dielectric fill material layer;
• a first contact assembly vertically extending through the contact-level dielectric layer and the first horizontally-extending portion of the dielectric fill material layer, located entirely within an area of said surface segment of the topmost surface of the layer stack, and including a first tubular insulating spacer laterally surrounding a first contact via structure that contacts a horizontal surface of the first metallic electrode layer, wherein the first tubular insulating spacer contacts a first cylindrical sidewall of the first horizontally-extending portion of the dielectric fill material layer, a first cylindrical sidewall of the second metallic electrode layer, and a first cylindrical sidewall of the third metallic electrode layer;
• a second contact assembly vertically extending through the contact-level dielectric layer and the first horizontally-extending portion of the dielectric fill material layer, located entirely within the area of said surface segment of the topmost surface of the layer stack, and including a second tubular insulating spacer laterally surrounding a second contact via structure that contacts a horizontal surface of the third metallic electrode layer, wherein the second tubular insulating spacer contacts a second cylindrical sidewall of the first horizontally-extending portion of the dielectric fill material layer;
• and
• a first metal pad structure comprising a bottom surface that contacts a top surface of the first contact via structure and a top surface of the second contact via structure.