Integrated capacitor with interlinked lateral fins

• US 7,956,438 B2
• Filed: 11/21/2008
• Issued: 06/07/2011
• Est. Priority Date: 11/21/2008
• Status: Active Grant

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Quinn, Patrick J.
• Primary Examiner(s): Chambliss; Alonzo
• Application Number:
  US12/276,292
• Publication Number:
  US 20100127351A1
• Time in Patent Office: 928 Days
• Field of Search: None
• US Class Current: 257/516
• CPC Class Codes: H01L 23/5223 Capacitor integral with wiring layers
• CPC Class Codes: H01L 27/0207 Geometrical layout of the components, e.g. computer aided design; custom LSI, semi-custom LSI, standard cell technique
• CPC Class Codes: H01L 27/0805 Capacitors only
• CPC Class Codes: H01L 28/86 having horizontal extensions
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/3011 Impedance

Abstract

A capacitor in an integrated circuit (“IC”) has a first node conductor formed in a first metal layer of the IC with a first spine extending along a first direction, a first vertical element extending from the first spine along a second direction perpendicular to the first direction. A first capital element extends along the first direction, and a first serif element extends from the capital element. The capacitor also has a second node conductor having a second spine, a second vertical element extending from the second spine toward the first spine, a second capital element, and a second serif element extending from the second capital between the first vertical element and the first serif element.

Claims

1. A capacitor in an integrated circuit (“

IC”

) comprising;

a first node conductor formed in a first metal layer of the IC having a first spine extending along a first direction, a first vertical element extending from the first spine along a second direction perpendicular to the first direction, a first capital element having a first end and a second end extending perpendicularly across an end of the first vertical element along the first direction, a first serif element extending from the first end of the first capital element toward the first spine, and a second serif element extending from the second end of the first capital element toward the first spine, the first vertical element, first capital element, first serif element and second serif element forming a first conductive fin, and a second conductive fin constructed as the first conductive fin extending perpendicularly from the first spine opposite the first conductive fin; and

a second node conductor formed in the first metal layer of the IC having a second spine extending along the first direction, a third conductive fin constructed as the first conductive fin having a third vertical element extending from the second spine along the second direction toward the first spine, and a third serif element extending from a third capital element of the third conductive fin toward the second spine, the third serif element being disposed between the first vertical element and the first serif element.

2. The capacitor of claim 1 further comprising a fourth conductive fin constructed as the first conductive fin extending from the second spine, a fourth serif element of the fourth conductive fin being disposed between the first vertical element and the second serif element.

3. The capacitor of claim 1 further comprising a first plurality of conductive fins, each of the first plurality of conductive fins constructed as the first conductive fin, extending from the first spine toward the second spine and a second plurality of conductive fins, each of the second plurality of conductive fins constructed as the first conductive fin, extending from the second spine interlinked with the first plurality of conductive fins.

4. The capacitor of claim 3 further comprising a third plurality of conductive fins, each of the third plurality of conductive fins constructed as the first conductive fin, extending from the first spine away from the second spine.

5. The capacitor of claim 4 wherein each of the third plurality of conductive fins is opposite a corresponding each of the first plurality of conductive fins along the first spine.

6. The capacitor of claim 3 wherein the second node conductor is a top node conductor and the second spine is an outermost spine of the top node conductor, the first node conductor further comprising a first node shield bar extending along the outermost spine of the top node conductor.

7. The capacitor of claim 3 wherein the second node conductor is a top node conductor further comprising a buss bar extending along the second direction, the second spine extending from the buss bar, and the first node conductor further comprising a first node shield bar extending along the buss bar.

8. The capacitor of claim 3 wherein the second node conductor is a top node conductor further comprising a buss bar and the second spine is an outermost spine of the top node conductor extending from the buss bar, the first node conductor further comprising a first node shield bar extending along the buss bar and a second node shield bar extending along the outermost spine.

9. The capacitor of claim 3 further comprising a second metal layer of the IC having a third plurality of conductive fins, each of the third plurality of conductive fins constructed as the first conductive fin, overlying the first plurality of conductive fins, and a fourth plurality of conductive fins, each of the fourth plurality of conductive fins constructed as the first conductive fin, overlying the second plurality of conductive fins.

10. The capacitor of claim 9 wherein the third plurality of conductive fins is electrically connected to the first plurality of conductive fins with a first plurality of conductive vias, and the fourth plurality of conductive fins is electrically connected to the second plurality of conductive fins with a second plurality of conductive vias.

18. The capacitor of claim 1 wherein the first vertical element has a width and a depth, the depth being greater than the width.

19. The capacitor of claim 1 further comprising a reference shield plate, the first metal layer being disposed between the reference shield plate and a substrate of the IC, the reference shield plate being electrically connected to an analog ground terminal of the IC.

11. A capacitor in an integrated circuit (“

IC”

) comprising;

a first node conductor formed in a metal layer of the IC having a first node buss bar, a plurality of first node spines extending from the first node buss bar, a first plurality of T-shaped fins extending from a first node spine in a first direction and a second plurality of T-shaped fins extending from the first node spine in a second direction opposite the first direction; and

a second node conductor formed in the metal layer having a second node buss bar, a plurality of second node spines extending from the second node buss bar, a third plurality of T-shaped fins extending from a second node spine in the first direction and interlinking with at least some of the second plurality of T-shaped fins.

12. The capacitor of claim 11 wherein the first node is a bottom node of a switching capacitor and the first node conductor further includes bottom node shield bar proximate to and extending along the second node buss bar.

13. The capacitor of claim 12 wherein the first node conductor further includes a second bottom node shield bar proximate to and extending along the second node spine.

14. The capacitor of claim 11 wherein the second plurality of T-shaped fins is a mirror image of the first plurality of T-shaped fins.

15. The capacitor of claim 11 further comprising

a second plurality of first node spines in a second metal layer of the IC and a fourth plurality of T-shaped fins connected to the first node in the second metal layer overlying the first plurality of T-shaped fins in the first metal layer;

a second plurality of second node spines in the second metal layer of the IC and a fifth plurality of T-shaped fins connected to the second node in the second metal layer overlying the third plurality of T-shaped fins;

a first plurality of conductive vias connecting at least some of the T-shaped fins in the first plurality to at least some of the T-shaped fins in the fourth plurality; and

a second plurality of conductive vias connecting at least some of the T-shaped fins in the third plurality to at least some of the T-shaped fins in the fifth plurality.

16. The capacitor of claim 11 further comprising

a second plurality of first node spines in a second metal layer of the IC and a fourth plurality of T-shaped fins connected to the first node in the second metal layer overlying the third plurality of T-shaped fins connected to the second node in the first metal layer;

and

a second plurality of second node spines in the second metal layer of the IC and a fifth plurality of T-shaped fins connected to the second node in the second metal layer overlying the first plurality of T-shaped fins connected to the first node in the first metal layer.

17. The capacitor of claim 11 wherein the IC is a field-programmable gate array having an analog section and further comprising a reference shield plate formed in an analog ground layer of the analog section.