Integrated circuit and a method using integrated process steps to form deep trench isolation structures and deep trench capacitor structures for the integrated circuit
View Patent ↗Disclosed is an integrated circuit having at least one deep trench isolation structure and a deep trench capacitor. A method of forming the integrated circuit incorporates a single etch process to simultaneously form first trench(s) and a second trenches for the deep trench isolation structure(s) and a deep trench capacitor, respectively. Following formation of a buried capacitor plate adjacent to the lower portion of the second trench, the trenches are lined with a conformal insulator layer and filled with a conductive material. Thus, for the deep trench capacitor, the conformal insulator layer functions as the capacitor dielectric and the conductive material as a capacitor plate in addition to the buried capacitor plate. A shallow trench isolation (STI) structure formed in the substrate extending across the top of the first trench(es) encapsulates the conductive material therein, thereby creating the deep trench isolation structure(s).
1. An integrated circuit structure comprising:
a substrate;
a first trench of a deep trench isolation structure in said substrate;
a shallow trench isolation structure in said substrate aligned above said first trench;
a second trench of a deep trench capacitor in said substrate;
a conformal insulator layer lining said first trench and only a lower portion of said second trench;
a conductive material on said conformal insulator layer within both said first trench and said second trench,
said shallow trench isolation structure above said first trench in combination with said conformal insulator layer lining said first trench encapsulate said conductive material within said first trench, and
said conductive material within said second trench filling said second trench up to a top surface of said substrate such that, within an upper portion of said second trench, said conductive material is positioned laterally immediately adjacent to said substrate;
a buried capacitor plate in said substrate adjacent to said lower portion of said second trench; and
a device comprising a doped region at said top surface of said substrate and positioned laterally immediately adjacent to said conductive material in said upper portion of said second trench such that said device is electrically connected to said deep trench capacitor; and
a second shallow trench isolation structure in said substrate and extending laterally from said substrate over only one edge of said second trench, said conductive material in said upper portion of said second trench being positioned laterally between said doped region and said second trench isolation structure, and said doped region, said conductive material in said upper portion of said second trench and said second shallow trench isolation structure having essentially coplanar top surfaces.
2. The integrated circuit structure of claim 1 , said first trench of said deep trench isolation structure comprising a continuous structure bordering a well region in said substrate.
3. The integrated circuit structure of claim 2 , further comprising an additional first trench of an additional deep trench isolation structure comprising an additional continuous structure adjacent to an outside edge of said continuous structure.
4. The integrated circuit structure of claim 1 , said second trench comprising a linear structure.
5. The integrated circuit structure of claim 1 , said first trench being less deep than said second trench.
6. The integrated circuit structure of claim 1 , said substrate further comprising a first well region having a first conductivity type and a second well region having a second conductivity type different from said first conductivity type, said deep trench isolation structure isolating said first well region from said second well region and said second trench of said deep trench capacitor being in said second well region of said substrate.
7. An integrated circuit structure comprising:
a substrate;
two adjacent first trenches of two deep trench isolation structures in said substrate;
a shallow trench isolation structure in said substrate aligned above said first trenches;
a second trench of a deep trench capacitor in said substrate, wherein at least one of said first trenches has a different depth than said second trench;
a conformal insulator layer lining said first trenches and only a lower portion of said second trench;
a conductive material on said conformal insulator layer within both said first trenches and said second trench,
said shallow trench isolation structure above said first trenches in combination with said conformal insulator layer lining said first trenches encapsulate said conductive material within said first trenches, and
said conductive material within said second trench filling said second trench up to a top surface of said substrate such that, within an upper portion of said second trench, said conductive material is positioned laterally immediately adjacent to said substrate;
a buried capacitor plate in said substrate adjacent to said lower portion of said second trench; and
a device comprising a doped region at a top surface of said substrate and positioned laterally immediately adjacent to said conductive material in said upper portion of said second trench such that said device is electrically connected to said deep trench capacitor.
8. The integrated circuit structure of claim 7 , said first trenches of said deep trench isolation structures comprising continuous essentially concentric structures bordering a well region in said substrate.
9. The integrated circuit structure of claim 8 , said first trenches having different depths.
10. The integrated circuit structure of claim 7 , said second trench comprising a linear structure.
11. The integrated circuit structure of claim 7 , said first trenches being less deep than said second trench.
12. The integrated circuit structure of claim 7 , further comprising a second shallow trench isolation structure in said substrate, said conductive material in said upper portion of said second trench being positioned laterally between said doped region and said second trench isolation structure being above only one edge of said second trench, and
said substrate further comprising a first well region having a first conductivity type and a second well region having a second conductivity type different from said first conductivity type, said deep trench isolation structure isolating said first well region from said second well region and said second trench of said deep trench capacitor being in said second well region of said substrate.
13. An integrated circuit structure comprising:
a substrate;
at least two adjacent first trenches of at least two adjacent deep trench isolation structures in said substrate;
a shallow trench isolation structure in said substrate aligned above said at least two adjacent first trenches;
a second trench of a deep trench capacitor said substrate;
a conformal insulator layer lining said first trenches and only a lower portion of said second trench;
a conductive material on said conformal insulator layer within both said first trenches and said second trench,
said shallow trench isolation structure above said first trenches in combination with said conformal insulator layer lining each of said first trenches to encapsulate said conductive material within said first trenches, and
said conductive material within said second trench filling said second trenchup to a top surface of said substrate such that, within an upper portion of said second trench, said conductive material is positioned laterally immediately adjacent to said substrate;
a buried capacitor plate in said substrate adjacent to a lower portion of said second trench;
a device comprising a doped region at said top surface of said substrate and positioned laterally immediately adjacent to said conductive material in said upper portion of said second trench such that said device is electrically connected to said deep trench capacitor; and
a second shallow trench isolation structure in said substrate, said conductive material in said upper portion of said second trench being positioned laterally between said doped region and said second trench isolation structure being above only one edge of said second trench.
14. The integrated circuit structure of claim 13 , said first trenches of said at least two adjacent deep isolation structures comprising continuous essentially concentric structures bordering a well region in said substrate.
15. The integrated circuit structure of claim 14 , said first trenches having different depths.
16. The integrated circuit structure of claim 14 , said first trenches having different widths.
17. The integrated circuit structure of claim 14 , said second trench comprising a linear structure.
18. The integrated circuit structure of claim 13 , said second trench having a different depth than each of said first trenches.
19. The integrated circuit structure of claim 13 , said first trenches being less deep than said second trench.