System and method for measuring a capacitance associated with an integrated circuit

• US 6,870,375 B2
• Filed: 07/01/2002
• Issued: 03/22/2005
• Est. Priority Date: 07/01/2002
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Gallia, James David, Deng, Xiaowei, Sarma, Robin C.
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): NGUYEN, HOAI AN D
• Application Number:
  US10/187,671
• Publication Number:
  US 20040000917A1
• Time in Patent Office: 995 Days
• Field of Search: 324/678, 324/686, 324/658, 324/649, 324/600, 324/515, 257/312, 257/595, 438/379, 733/350.4, 738/623.37, 738/626.26, 367/181, 340/545.4, 340/562, 320/167, 702/47, 702/52
• US Class Current: 324/658
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G01R 31/2851 Testing of integrated circuits [IC] G01R31/317 takes precedence; testing individual devices G01R31/26; testing printed circuits G01R31/2801
• CPC Class Codes: G01R 31/30 Marginal testing, e.g. by varying supply voltage testing computers during standby operation or idle time G06F11/22
• CPC Class Codes: G11C 2029/5002 Characteristic

Abstract

A method for measuring a capacitance associated with a portion of an integrated circuit is provided that includes coupling a measurement circuit to an integrated circuit. One or more transistors within the integrated circuit are initialized such that a steady-state associated with one or more of the transistors is achieved. A capacitance associated with the portion of the integrated circuit is then measured using the measurement circuit. The portion of the integrated circuit is selectively charged and discharged in response to a voltage potential being applied thereto such that a drain current is generated that serves as a basis for the capacitance measurement.

Claims

1. A method for measuring a capacitance associated with a portion of an integrated circuit comprising:

coupling a measurement circuit to an integrated circuit;

initializing one or more transistors within the integrated circuit;

measuring a capacitance associated with a portion of the integrated circuit using the measurement circuit, the portion of the integrated circuit being selectively charged and discharged in response to a voltage potential being applied thereto such that a drain current is generated that serves as a basis for the capacitance measurement; and

separating the capacitance measurement associated with the portion of the integrated circuit into a capacitance associated with the transistors included within the integrated circuit and a capacitance associated with one or more interconnects that are coupled to the transistors.

2. The method of claim 1, wherein the portion of the integrated circuit defines a static random access memory (SRAM) element.

3. The method of claim 2, further comprising:

duplicating the SRAM element multiple times before executing the capacitance measurement associated with the portion of the integrated circuit.

4. The method of claim 1, further comprising:

comparing the capacitance measurement associated with the portion of the integrated circuit to a reference set of capacitance values such that a parameter associated with the manufacturing process that generated the integrated circuit may be checked.

5. The method of claim 4, wherein the parameter associated with the manufacturing process is selected from the group consisting of:

(a) specifications associated with the transistor;

(b) a width of a selected one of the conductors;

(c) a thickness of a selected one of the conductors;

(d) a thickness associated with a dielectric positioned proximate to a selected two or more of the conductors; and

(e) a spacing between a selected two or more of the conductors.

6. The method of claim 5, wherein the reference set of capacitance values is based on a simulation element having substantially the same structural characteristics as the integrated circuit.

7. The method of claim 5, wherein the manufacturing process that generated the integrated circuit is changed in response to comparing the capacitance measurement associated with the portion of the integrated circuit to the reference set of capacitance values.

8. An apparatus for measuring a capacitance associated with a portion of an integrated circuit comprising:

an integrated circuit that includes one or more transistors;

a measurement circuit coupled to the integrated circuit and operable to initialize one or more of the transistors within the integrated circuit such that a steady-state associated with one or more of the transistors is achieved, wherein the measurement circuit is used to measure a capacitance associated with a portion of the integrated circuit, the portion of the integrated circuit being selectively charged and discharged in response to a voltage potential being applied thereto such that a drain current is generated that serves as a basis for the capacitance measurement; and

wherein the capacitance measurement associated with the portion of the integrated circuit is separated into a capacitance associated with the transistors included within the integrated circuit and a capacitance associated with one or more interconnects that are coupled to the transistors.

9. The apparatus of claim 8, wherein the portion of the integrated circuit defines a static random access memory (SRAM) element.

10. The apparatus of claim 9, wherein the SRAM element is duplicated multiple times before executing the capacitance measurement associated with the portion of the integrated circuit.

11. The apparatus of claim 8, further comprising:

a reference set of capacitance values, wherein the capacitance measurement associated with the portion of the integrated circuit may be compared to the reference set of capacitance values such that a parameter associated with the manufacturing process that generated the integrated circuit may be checked.

12. The apparatus of claim 11, wherein the parameter associated with the manufacturing process is selected from the group consisting of:

(a) specifications associated with the transistor;

(b) a width of a selected one of the conductors;

(c) a thickness of a selected one of the conductors;

(d) a thickness associated with a dielectric positioned proximate to a selected two or more of the conductors; and

(e) a spacing between a selected two or more of the conductors.

13. The apparatus of claim 12, wherein the reference set of capacitance values is based on a simulation element having substantially the same structural characteristics as the integrated circuit.

14. The apparatus of claim 12, wherein the manufacturing process that generated the integrated circuit is changed in response to comparing the capacitance measurement associated with the portion of the integrated circuit to the reference set of capacitance values.

15. A system for measuring a capacitance associated with a portion of an integrated circuit comprising:

a measurement circuit operable to initialize one or more transistors within an integrated circuit such that a steady-state associated with one or more of the transistors is achieved, wherein the measurement circuit is coupled to the integrated circuit which is selectively charged and discharged in response to a voltage potential being applied thereto such that a drain current is generated that serves as a basis for the capacitance measurement; and

wherein the capacitance measurement associated with the portion of the integrated circuit is separated into a capacitance associated with the transistors included within the integrated circuit and a capacitance associated with one or more interconnects that are coupled to the transistors.

16. The system of claim 15, wherein the portion of the integrated circuit defines a static random access memory (SRAM) element.

17. The system of claim 16, wherein the SRAM element is duplicated multiple times before executing the capacitance measurement associated with the portion of the integrated circuit.