Method and apparatus for implementing a metal capacitor with L-shaped fingers

Patent metadata

Field	Value
Publication number	US-9196676-B1
Application number	US-201313957829-A
Country	US
Kind code	B1
Filing date	Aug 2, 2013
Priority date	Feb 11, 2009
Publication date	Nov 24, 2015
Grant date	Nov 24, 2015

Abstract

A metal capacitor includes a plurality of interconnect segments. A first plurality of L-shaped fingers is driven to a first voltage level by a first interconnect segment. A second plurality of L-shaped fingers is driven to a second voltage level by a second interconnect segment. Each of the L-shaped fingers from a set of the first plurality of L-shaped fingers is adjacent to at least one of the L-shaped fingers from a set of the second plurality of L-shaped fingers.

First claim

What is claimed is:

1. A metal capacitor, comprising:
a first plurality of L-shaped fingers driven to a first voltage level by a first interconnect segment;
a second plurality of L-shaped fingers driven to a second voltage level by a second interconnect segment;
a third plurality of L-shaped fingers driven to the first voltage level by a third interconnect segment; and
a fourth plurality of L-shaped fingers driven to the second voltage level by a fourth interconnect segment, wherein a substantial portion of a length of each of the L-shaped fingers from the first plurality of L-shaped fingers is directly adjacent to at least one of the L-shaped fingers from the second plurality of L-shaped fingers, and wherein the first, second, third, and fourth interconnect segments have a same length and width and are physically detached from each other.

2. The apparatus of claim 1 , wherein the first, second, third, and fourth interconnect segments all reside on a same layer of a semiconductor substrate.

3. The apparatus of claim 1 , wherein the first plurality of L-shaped fingers and the second plurality of L-shaped fingers have identical patterns.

4. The apparatus of claim 1 , wherein the first plurality of L-shaped fingers and the second plurality of L-shaped fingers reside on a first layer of a semiconductor substrate.

5. The apparatus of claim 1 , wherein the first plurality of L-shaped fingers are not directly coupled to another metal layer.

6. The apparatus of claim 1 , wherein the first interconnect segment is not coupled to a finger coupled to another interconnect segment.

7. The apparatus of claim 1 , wherein the first, second, third and fourth interconnect segments all reside on a same layer as the first, second, third, and fourth plurality of L-shaped fingers.

8. The apparatus of claim 1 , wherein the first interconnect segment is positioned 90 degrees from the second interconnect segment.

9. The apparatus of claim 1 , wherein each of the third plurality of L-shaped fingers is directly adjacent to at least one of the fourth plurality of L-shaped fingers.

10. A metal capacitor, comprising:
a first plurality of L-shaped fingers, residing on a first layer of a semiconductor substrate, connected together and driven to a first voltage level by a first interconnect segment on the first layer;
a second plurality of L-shaped fingers, residing on the first layer of the semiconductor substrate, connected together and driven to a second voltage level by a second interconnect segment on the first layer, wherein both a horizontal and vertical segment of each of the first plurality of L-shaped fingers are directly adjacent to at least one of the second plurality of L-shaped fingers;
a third plurality of L-shaped fingers, residing on the first layer of the semiconductor substrate, connected together and driven to the first voltage level by a third interconnect segment on the first layer; and
a fourth plurality of L-shaped fingers, residing on the first layer of the semiconductor substrate, connected together and driven to the second voltage level by a fourth interconnect segment on the first layer, wherein the first interconnect segment, the second interconnect segment, the third interconnect segment, and the fourth interconnect segment are physically detached from each other.

11. The apparatus of claim 10 , wherein the first interconnect segment, the second interconnect segment, the third interconnect segment, and the fourth interconnect segment have a same length and width.

12. The apparatus of claim 10 , wherein the first plurality of L-shaped fingers and the second plurality of L-shaped fingers have identical patterns.

13. The apparatus of claim 10 , wherein the first and second interconnect segments contribute parasitic capacitance to the metal capacitor.

14. The apparatus of claim 10 , wherein only the plurality of L-shaped fingers contribute to the capacitor density of the metal capacitor.

15. The apparatus of claim 10 , wherein the first plurality of L-shaped fingers have a same dimension as the second plurality of L-shaped fingers.

16. The apparatus of claim 10 , wherein the first plurality of L-shaped fingers are not directly coupled to another metal layer.

17. The apparatus of claim 10 , wherein the first interconnect segment is not coupled to a finger coupled to another interconnect segment.

18. The apparatus of claim 10 , wherein each of the third plurality of L-shaped fingers is directly adjacent to at least one of the fourth plurality of L-shaped fingers.

19. A metal capacitor array structure, comprising:
a plurality of metal capacitors each having a first plurality of L-shaped fingers driven to a first voltage level by a first interconnect segment, a second plurality of L-shaped fingers driven to a second voltage level by a second interconnect segment positioned 90 degrees from the first interconnect segment, a third plurality of L-shaped fingers driven to the first voltage level by a third interconnect segment, and a fourth plurality of L-shaped fingers driven to the second voltage level by a fourth interconnect segment, wherein the first, second, third, and fourth interconnect segments reside on a same layer of a semiconductor substrate and are physically detached from each other.

20. The apparatus of claim 19 , wherein the plurality of metal capacitors are configurable to connect one or more of the plurality of metal capacitors in parallel to satisfy a target capacitance value.

21. The apparatus of claim 19 , wherein the first plurality and second plurality of L-shaped fingers contribute to a capacitor density of the metal capacitors without contributing to a parasitic capacitance of the metal capacitors.

22. The apparatus of claim 19 , wherein each of the L-shaped fingers from a set of the first plurality of L-shaped fingers from a first capacitor is adjacent to at least one of the L-shaped fingers from a set of the second plurality of L-shaped fingers from the first capacitor.

Assignees

• Altera Corp

Inventors

• Chen Shuxian
• Watt Jeffrey T

Classifications

• H10W20/496

  Capacitor integral with wiring layers · CPC title

• H10D89/10

  Integrated device layouts · CPC title

• H10D1/714 Primary

  having horizontal extensions · CPC title

• H01G4/005

  Electrodes · CPC title

• H01L28/86 Primary

  Electricity · mapped topic