Three-dimensional metal-insulator-metal capacitor embedded in seal structure
Embodiments of the present invention are directed to methods and resulting structures for integrated circuits having metal-insulator-metal (MIM) capacitors that serve as both decoupling capacitors and crack stops. In a non-limiting embodiment, an interconnect is formed on a first portion of a substrate in an interior region of the integrated circuit. A second portion of the substrate is exposed in an edge region of the integrated circuit. A MIM capacitor is formed over the second portion of the substrate in the edge region. The MIM capacitor includes two or more plates and one or more dielectric layers. Each dielectric layer is positioned between an adjacent pair of the two or more plates and a portion of the two or more plates extends over the interconnect in the interior region. A plate of the two or more plates is electrically coupled to a last metal wiring level of the interconnect.
1. A method for forming an integrated circuit, the method comprising:
forming an interconnect on a first portion of a substrate in an interior region of the integrated circuit, the interconnect comprising a last metal wiring level, the interconnect further comprising one or more metal lines and one or more vias electrically coupled to a front end of line (FEOL) device;
forming a trench exposing a second portion of the substrate in an edge region of the integrated circuit, the trench in the edge region adjacent to the interconnect in the interior region;
forming a metal-insulator-metal (MIM) capacitor over the second portion of the substrate in the edge region, the MIM capacitor comprising two or more plates and one or more dielectric layers, wherein each dielectric layer is positioned between an adjacent pair of the two or more plates, and wherein a portion of the two or more plates extends over the interconnect in the interior region; and
electrically coupling a plate of the two or more plates to the last metal wiring level of the interconnect.
2. The method of claim 1 , wherein the MIM capacitor is configured both as a decoupling capacitor and as a crack stop for the integrated circuit.
3. The method of claim 1 , wherein exposing the second portion of the substrate comprises forming a trench.
4. The method of claim 3 further comprising forming a metal wall on sidewalls and a bottom surface of the trench, the metal wall between the MIM capacitor and the substrate.
5. The method of claim 4 , wherein the metal wall and the MIM capacitor together define a seal ring positioned around an outer perimeter of the interior region.
6. The method of claim 3 further comprising forming a dielectric wall on sidewalls and a bottom surface of the trench, the dielectric wall between the MIM capacitor and the substrate.
7. The method of claim 1 , wherein electrically coupling the plate of the two or more plates to the last metal wiring level comprises:
forming a contact over the last metal wiring level; and
forming a via between the contact and the last metal wiring level;
wherein a portion of the via is in direct contact with the plate.
8. The method of claim 7 , wherein a second plate of the two or more plates is electrically isolated from the via.