INTERDIGITATED CAPACITOR HAVING DIGITS OF VARYING WIDTH

• US 20130063861A1
• Filed: 09/09/2011
• Published: 03/14/2013
• Est. Priority Date: 09/09/2011
• Status: Active Grant

• Current Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Original Assignee: Xilinx, Inc. (Advanced Micro Devices, Inc.)
• Inventors: Wu, Zhaoyin D., Upadhyaya, Parag, Jiang, Xuewen
• Granted Patent: US 8,941,974 B2
• Time in Patent Office: Days
• US Class Current: 361/305
• CPC Class Codes: H01L 28/86 having horizontal extensions
• CPC Class Codes: Y10T 29/43 Electric condenser making

Abstract

An interdigitated capacitor having digits of varying width is disclosed. One embodiment of a capacitor includes a first plurality of conductive digits and a second plurality of conductive digits positioned in an interlocking manner with the first plurality of conductive digits, such that an interdigitated structure is formed. The first plurality of conductive digits and the second plurality of conductive digits collectively form a set of digits, where the width of a first digit in the set of digits is non-uniform with respect to a second digit in the set of digits.

Claims

1. A capacitor comprising:

a first plurality of conductive digits; and

a second plurality of conductive digits positioned in an interlocking manner with the first plurality of conductive digits such that an interdigitated structure is formed,

wherein the first plurality of conductive digits and the second plurality of conductive digits collectively form a set of digits, and wherein a width of a first digit in the set of digits is non-uniform with respect to a second digit in the set of digits.

2. The capacitor of claim 1, wherein a first subset of the set of digits that is positioned closest to ends of the interdigitated structure has widths that are wider than a second subset of the set of digits that is positioned closest to a center of the interdigitated structure.

3. The capacitor of claim 1, wherein a first subset of the set of digits that is positioned closest to ends of the interdigitated structure has widths that are three to five times wider than a second subset of the set of digits that is positioned closest to a center of the interdigitated structure.

4. The capacitor of claim 1, wherein a first defined number of a subset of the set of digits that is positioned closest to ends of the interdigitated structure has a first width, and a remainder of the digits in the set of digits has a second width that is narrower than the first width.

5. The capacitor of claim 1, wherein the width of each digit in the set of digits gradually tapers from a widest width at digits positioned at ends of the interdigitated structure to a narrowest width at a digit positioned at a center of the interdigitated structure.

6. The capacitor of claim 1, wherein relative widths of the digits in the set of digits are determined in accordance with a magnetic H field distribution of the interdigitated structure.

7. The capacitor of claim 6, wherein a width of a particular one of the set of digits is proportional to an amount of current carried by the particular one of set of digits.

8. The capacitor of claim 1, wherein gaps between the digits in the set of digits are substantially uniform in size.

9. The capacitor of claim 1, wherein the first plurality of conductive digits and the second plurality of conductive digits are formed from at least one of:

copper, doped polysilicon, aluminum, or titanium nitride.

10. The capacitor of claim 1, wherein the first plurality of conductive digits is formed from a first material, and the second plurality of conductive digits is formed from a second material that is different from the first material.

11. The capacitor of claim 1, further comprising:

at least one bar coupled to the interdigitated structure wherein the at least one bar having at least one feeding point.

12. The capacitor of claim 11, wherein a first subset of the set of digits that is positioned closest to the at least one feeding point has widths that are wider than a remainder of the set of digits.

13. A method for forming a capacitor, the method comprising:

forming a first plurality of conductive digits; and

forming a second plurality of conductive digits positioned in an interlocking manner with the first plurality of conductive digits such that an interdigitated structure is formed,

wherein the first plurality of conductive digits and the second plurality of conductive digits collectively form a set of digits, and wherein a width of a first digit in the set of digits is non-uniform with respect to a second digit in the set of digits.

14. The method of claim 13, wherein a first subset of the set of digits that is positioned closest to a feeding point of a bar that is coupled to the interdigitated structure has widths that are wider than a second subset of the set of digits that is positioned farthest away from the feeding point of the bar.

15. The method of claim 13, wherein a first subset of the set of digits that is positioned closest to a feeding point of a bar that is coupled to the interdigitated structure has widths that are three to five times wider than a second subset of the set of digits that is positioned farthest away from the feeding point of the bar.

16. The method of claim 13, wherein a first defined number of a subset of the set of digits that is positioned closest to a feeding point of a bar that is coupled to the interdigitated structure has a first width, and a remainder of the digits in the set of digits has a second width that is narrower than the first width.

17. The method of claim 13, wherein the width of each digit in the set of digits gradually tapers from a widest width at digits positioned near a feeding point of a bar that is coupled to the interdigitated structure to a narrowest width at a digit positioned farthest away from the feeding point of the bar.

18. The method of claim 13, wherein relative widths of the digits in the set of digits are determined in accordance with a magnetic H field distribution of the interdigitated structure, and wherein a width of a particular one of the set of digits is proportional to an amount of current carried by the particular one of the set of digits.

19. The method of claim 13, wherein at least one bar having a feeding point is coupled to the interdigitated structure, and wherein a first subset of the set of digits that is positioned closest to the feeding point has widths that are wider than a remainder of the set of digits.

20. A capacitor comprising:

a single interdigitated layer, wherein the single interdigitated layer comprises;

a first plurality of conductive digits; and

a second plurality of conductive digits positioned in an interlocking manner with the first plurality of conductive digits such that an interdigitated structure is formed.