Technique for evaluating a fabrication of a die and wafer

• US 7,220,990 B2
• Filed: 08/25/2004
• Issued: 05/22/2007
• Est. Priority Date: 08/25/2003
• Status: Active Grant

• Current Assignee: Tau-Metrix, Inc.
• Original Assignee: Tau-Metrix, Inc.
• Inventors: Pakdaman, Nader, Aghababazadeh, Majid, Steinbrueck, Gary L., Vickers, James S., Estabil, Jose J.
• Primary Examiner(s): Tran; Long K.
• Application Number:
  US10/927,260
• Publication Number:
  US 20050085032A1
• Time in Patent Office: 1,000 Days
• Field of Search: 257/48, 257/620, 257/E21.521, 257/E21.529, 257/E21.531, 438/11, 438/14, 438/15, 438/18, 700/121, 700/30, 700/108
• US Class Current: 257/48
• CPC Class Codes: G01R 31/2831 Testing of materials or semi-finished products, e.g. semiconductor wafers or substrates G01R31/318511 takes precedence; testing during manufacture H01L22/00
• CPC Class Codes: G01R 31/3025 Wireless interface with the DUT
• CPC Class Codes: G01R 31/31707 Test strategies methods for generation of test sequences G01R31/318371
• CPC Class Codes: G01R 31/31718 Logistic aspects, e.g. binning, selection, sorting of devices under test, tester/handler interaction networks, Test management software, e.g. software for test statistics or test evaluation, yield analysis mechanical aspects G01R31/2808, G01R31/2851
• CPC Class Codes: G01R 31/318505 Test of Modular systems, e.g. Wafers, MCM's
• CPC Class Codes: G01R 31/318511 Wafer Test
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• CPC Class Codes: H01L 22/34 Circuits for electrically characterising or monitoring manufacturing processes, e. g. whole test die, wafers filled with test structures, on-board-devices incorporated on each die, process control monitors or pad structures thereof, devices in scribe line switching, multiplexing, gating devices G01R19/25; process control with lithography, e.g. dose control, G03F7/20; structures for alignment control by optical means G03F7/70633
• 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

Abstract

The fabrication of the wafer may be analyzed starting from when the wafer is in a partially fabricated state. The value of a specified performance parameter may be determined at a plurality of locations on an active area of a die of the wafer. The specified performance parameter is known to be indicative of a particular fabrication process in the fabrication. Evaluation information may then be obtained based on a variance of the value of the performance parameter at the plurality of locations. This may be done without affecting a usability of a chip that is created from the die. The evaluation information may be used to evaluate how one or more processes that include the particular fabrication process that was indicated by the performance parameter value was performed.

Claims

1. A system for evaluating a fabrication of a wafer that includes one or more die, the system comprising:

a plurality of test structures disposed on at least some of the one or more die, wherein the plurality of test structures are identifiable as belonging to one or more classes in a plurality of classes, and wherein each class of test structures includes;

a combination of device and interconnect elements that are provided on the die prior to the fabrication being completed, wherein the combination can be activated to cause an electrical activity that is detectable without affecting a usability of a chip formed from the die after fabrication is completed;

wherein each combination is configured so that (i) the electrical activity of that combination identifies a value that indicates an attribute or result of one or more steps in the fabrication, and (ii) the electrical activity of that combination is not or is less indicative of an attribute or result of at least another step in the fabrication;

wherein the value of each fabrication step in the class of test structures can be used, either individually or in combination with the value of one or more fabrication steps from another class of test structures, to determine information on a result of a particular fabrication step.

2. The system of claim 1, wherein the plurality of test structures may be triggered concurrently.

3. The system of claim 2, wherein the electrical activity from at least some of the plurality of test structures identify those test structures from other test structures on the wafer.

4. The system of claim 3, wherein the electrical activity from at least some of the plurality of test structures are detectable using a common detection apparatus that scans at least some of the wafer without making contact.

5. The system of claim 1, wherein the fabrication step that is indicated by the electrical activity of one or more of the plurality of test structures that corresponds to a physical property that is present within the chip.

6. The system of claim 1, wherein the fabrication step that is indicated by the electrical activity of one or more of the plurality of test structures corresponds to an electrical property that is present within the chip.

7. The system of claim 1, wherein each of the plurality of test structures are at least partially tiggerable by a common energy beam.

8. The system of claim 7, wherein the electrical activity of one or more of the plurality of test structures includes photons produced from a switch element in the combination of device and interconnect elements of the one or more test structures.

9. The system of claim 1, wherein the electrical activity of one or more of the plurality of test structures includes at least one of an electrostatic, electromagnetic, or inductive signal that is created by an output of each of the one or more test structures in response to being triggered.

10. The system of claim 9, wherein the radio-frequency signal of each of the one or more test structures has a characteristic that identifies the test structure from other test structures on the chip.

11. The system of claim 1, wherein the electrical activity of the plurality of test structures are detectable without contact being made to the chip.

12. The system of claim 1, wherein the combination of one or more test structures includes a plurality of interconnected inverters.

13. The system of claim 12, wherein the combination the one or more test structures includes one or more CMOS inverters.

14. The system of claim 1, wherein the combination of one or more of the plurality of test structures includes a plurality of transistors, and wherein each combination of the one or more test structures is configured to minimize a relationship of transistor gate lengths to transistor gate widths for the plurality of transistors.

15. The system of claim 1, wherein the combination of device and interconnect elements includes a plurality of transistors, and wherein the combination is configured to exaggerate the influence of transistor gate widths to transistor gate lengths and other electrical parameters for the plurality of transistors.

16. The system of claim 1, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, wherein the combination is configured to exaggerate the influence of interconnect resistance.

17. The system of claim 1, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, wherein the combination is configured to exaggerate the influence of interconnect capacitance.

18. The system of claim 1, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, wherein the combination is configured to exaggerate the influence of gate capacitance.

19. The system of claim 18, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, wherein the combination is configured to exaggerate the influence of gate film stack on gate.

20. The system of claim 18, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, wherein the combination is configured to exaggerate the influence of gate photo and etch.

21. The system of claim 18, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, wherein the combination is configured to exaggerate the influence of gate source drain extension implant.

22. The system of claim 1, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, wherein the combination is configured to exaggerate the influence of Contact Resistance.

23. The system of claim 1, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, wherein the combination is configured to exaggerate the influence of Contact Resistance.

24. The system of claim 1, wherein the combination of device and interconnect elements are configured to emphasize the attribute or result of the given fabrication step over an attribute or result of any other step in the fabrication.

25. The system of claim 1, wherein the combination of device and interconnect elements are configured to be indicative of only the given fabrication step.

26. The system of claim 1, wherein the electrical activity caused by the combination corresponds to one or more of(i) an output signal, (ii) photon emission, (iii) electron emissions, and (iv) an electrical effect.

27. The system of claim 1, wherein the electrical activity caused by the combination corresponds to one or more of (i) an output signal, (ii) photon emission, (iii) electron emissions, and (iv) an electrical effect.

28. The system of claim 1, wherein one or more of the plurality of test structure can be at least partially activated by an energy beam, and wherein the electrical activity includes at least one of an electrostatic, electromagnetic, and inductive signal.

29. The system of claim 1, wherein one or more of the plurality of test structures can be at least partially activated by an energy beam, and wherein the electrical activity includes photons produced from a switch element in the combination of device and interconnect elements.

30. The test structure of claim 29, wherein the electrical activity from the one or more test structures has a characteristic that identifies that test structure from at least some of the other test structures on the die.

31. The system of claim 1, wherein one or more of the plurality of test structures include a ring oscillator.

51. The system of claim 31, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, and wherein the combination is configured to be activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of contact resistance amongst the plurality of transistors and the interconnect device.

32. A system for evaluating a fabrication of a wafer, the system comprising:

a combination of device and interconnect elements that are identifiable on an active region of a die on the wafer prior to the fabrication of the wafer being completed, wherein the combination can be activated to cause electrical activity that is detectable without affecting a usability of the die or wafer and

wherein the combination of device and interconnect elements is configured so that the electrical activity (i) emphasizes a given fabrication step in the fabrication sequence over another step in the fabrication sequence, and (ii) indicates a value or variation of an attribute or result of the given fabrication step on at least a segment of the die; and

a data acquisition and analysis resource to evaluate the fabrication of the wafer using, at least in part, the value or the variation of the attribute or the result of the given fabrication step.

33. The system of claim 32, wherein the attribute or result of the given fabrication step corresponds to a particular set of one or more physical properties that is present within the active region of the die.

34. The system of claim 33, wherein the combination of device and interconnect elements includes one or more CMOS inverters.

35. The system of claim 32, wherein the attribute or result of the given fabrication step corresponds to an electrical property that is present within the active region of the die.

36. The system of claim 32, wherein the combination of device and interconnect elements are configured so that the electrical activity produced by the combination of device and interconnect elements emphasizes, for the data acquisition and analysis resource, the attribute or result of the given fabrication step over an attribute or result of any other step in the fabrication.

37. The system of claim 32, wherein the combination of device and interconnect elements are configured so that the electrical activity produced by the combination of device and interconnect elements are indicative of only the given fabrication step to the data acquisition and analysis resource.

38. The system of claim 32, wherein the electrical activity corresponds to one or more of (i) an output signal, (ii) photon emission, (iii) electron emissions, and (iv) an electrical effect.

39. The system of claim 32, wherein the test structure can be at least partially activated by an energy beam, and wherein the electrical activity includes photons produced from a switch element in the combination of device and interconnect elements.

40. The system of claim 32, wherein the test structure can be at least partially activated by an energy beam, and wherein the electrical activity includes at least one of an electrostatic, electromagnetic, and inductive signal.

41. The system of claim 32, wherein the combination of device and interconnect elements includes a plurality of interconnected inverter.

42. The system of claim 32, wherein the combination of device and interconnect elements includes a plurality of transistors, and wherein the combination is configured to be activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of transistor gate lengths to transistor gate widths and other electrical parameters for the plurality of transistors.

43. The system of claim 32, wherein the combination of device and interconnect elements includes a plurality of transistors, and wherein the combination is configured to be activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of transistor gate widths to transistor gate lengths and other electrical parameters for the plurality of transistors.

44. The system of claim 32, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, and wherein the combination is configured to be activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of interconnect resistance amongst the plurality of transistors and the interconnect device.

45. The system of claim 32, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, and wherein the combination is configured to be activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of interconnect capacitance and/or inductance amongst the plurality of transistors and interconnect device.

46. The system of claim 32, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, and wherein the combination is configured to he activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of gate capacitance amongst the plurality of transistors and interconnect device.

47. The system of claim 32, wherein the electrical activity has a characteristic that identifies the test structure from at least some of the other test structures on the die.

48. The system of claim 47, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, and wherein the combination is configured to be activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of gate film stack on one or more gates of the plurality of transistors.

49. The system of claim 47, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, and wherein the combination is configured to be activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of a photoresist step and an etch step in the fabrication sequence.

50. The system of claim 47, wherein the combination of device and interconnect elements includes a plurality of transistors and an interconnect device, and wherein the combination is configured to be activated to produce electrical activity that exaggerates, at least to the data acquisition and analysis resource, the influence of a gate source drain extension implant.

52. The system of claim 32, wherein the combination of device and interconnect elements are distributed on one or more of a plurality of die, partial die, and a scribe region of the wafer, and wherein the combination of device and interconnect elements can be activated to cause electrical activity that emphasizes, to at least the data acquisition and analysis resource, one or more fabrication steps over other fabrication steps in the fabrication of the wafer.

53. The system of claim 32, wherein the combination of device and interconnect elements can be activated by a stimulating signal.

54. The system of claim 32, wherein the combination of device and interconnect elements can be activated by a modulating signal.

55. The system of claim 32, wherein the data acquisition and analysis resource includes one or more of software, firmware or hardware.

56. The system of claim 32, wherein the data acquisition and analysis resource evaluates the fabrication of the wafer by using the value of the attribute or result of the given fabrication step to determine, before fabrication is complete, information indicating a performance of a chip formed from the active region of the die.

57. The system of claim 56, wherein the data acquisition and analysis resource evaluates the fabrication of the wafer by using the value of the attribute or result of a first metal deposition step.

58. The system of claim 32, wherein the data acquisition and analysis resource includes a device modeling resource.

59. The system of claim 32, wherein one or more of the plurality of test structures included a ring oscillator.