Method of inspecting circuit pattern and inspecting instrument

• US 20030206027A1
• Filed: 05/07/2003
• Published: 11/06/2003
• Est. Priority Date: 04/28/1999
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Nozoe, Mari, Watanabe, Kenji, Miyai, Hiroshi, Tanaka, Maki, Sugimoto, Aritoshi, Shinada, Hiroyuki, Morioka, Hiroshi, Saiki, Keiichi
• Granted Patent: US 6,703,850 B2
• Time in Patent Office: Days
• US Class Current: 324/751
• CPC Class Codes: G01R 31/307 of integrated circuits
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: H01J 2237/221 Image processing
• CPC Class Codes: H01J 2237/2817 Pattern inspection
• CPC Class Codes: H01J 37/265 Controlling the tube; circuit arrangements adapted to a particular application not otherwise provided, e.g. bright-field-dark-field illumination
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• 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

In order to obtain optimum irradiation conditions of an electron beam according to the material and structure of a circuit pattern to be inspected and the kind of a failure to be detected and inspect under the optimum conditions without delay of the inspection time, an inspection device for irradiating the electron beam 19 to the sample board 9 which is a sample, detecting generated secondary electrons by the detector 7, storing obtained signals sequentially in the storage, comparing the same pattern stored in the storage by the comparison calculation unit, and extracting a failure by comparing the predetermined threshold value with the comparison signal by the failure decision unit is provided, wherein the optimum value of the irradiation energy is stored in the data base inside the device beforehand according to the structure of a sample and a recommended value of the irradiation energy suited to inspection can be searched for by inputting or selecting the irradiation energy by a user or inputting information regarding the structure of an article to be inspected.

Claims

1. A circuit pattern inspection method having a step of scanning a board surface with a pattern formed on a sample with an electron beam, a step of applying a voltage to said sample, a step of detecting a signal secondarily generated from said board surface by said electron beam, a step of forming an electron beam image of said board surface from said detected signal, and a step of storing said electron beam image and including a step of deciding a failure from said stored image, wherein said method includes a step of finding electron beam irradiation conditions for entering onto said board surface according to a pattern to be inspected.

4. An inspection method according to any of claims 1 to 3, wherein said method has a step of obtaining said electron beam irradiation conditions from the contrast of said electron beam image as a step of finding said conditions.

5. A circuit pattern inspection method according to any of claims 1 to 3, wherein said method sets any or all of the irradiation energy of said electron beam to said sample, the beam current of said electron beam, and the electron beam irradiation count to the same area as a step of setting said electron beam irradiation conditions according to said circuit pattern to be inspected.

6. A circuit pattern inspection method according to any of claims 1 to 3, wherein said method builds, sets, and stores a data base for various kinds of inspection conditions including said electron beam irradiation conditions beforehand and reads said data base at the time of inspection execution as a step of setting said electron beam irradiation conditions according to said circuit pattern to be inspected.

9. A circuit pattern inspection method according to any of claims 1 to 3, wherein said electron beam irradiation conditions are set according to the material of said circuit pattern to be inspected.

10. A circuit pattern inspection method according to any of claims 1 to 3, wherein inspection conditions are set according to the step of said circuit pattern to be inspected.

11. A circuit pattern inspection method according to any of claims 1 to 3, wherein said electron beam irradiation conditions are set according to the pattern size and pattern shape of said circuit pattern to be inspected.

12. A circuit pattern inspection method according to any of claims 1 to 3, wherein said electron beam irradiation conditions are set according to the kind of a failure to be detected on said circuit pattern to be inspected.

13. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the surface material of said circuit pattern to be inspected is a photosensitive resist, said electron beam irradiation energy is set within the range from 300 V to 3 kV.

14. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the surface material of said circuit pattern to be inspected is a combination of an insulating material and a conductive material, said electron beam irradiation energy is set within the range from 300 V to 5 kV.

15. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the surface material of said circuit pattern to be inspected is a combination of an insulating material and a different insulating material, said electron beam irradiation energy is set within the range from 1500 V to 5 kV.

16. A circuit pattern inspection method according to any of claims 1 to 12, wherein when said step of said circuit pattern to be inspected is 0.3 μ

m or more, said electron beam irradiation energy is set within the range from 1500 V to 5 kV.

17. A circuit pattern inspection method according to any of claims 1 to 12, wherein when said step of said circuit pattern to be inspected is less than 0.3 m, said electron beam irradiation energy is set within the range from 300 V to 3 kV.

18. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the kind of a failure to be detect on said circuit pattern to be inspected is a non-conduction failure of a contact hole, said electron beam irradiation energy is set within the range from 300 V to 3 kV.

19. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the kind of a failure to be detect on said circuit pattern to be inspected is a short defect of a transistor or line, said electron beam irradiation energy is set within the range from 300 V to 3 kV.

20. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the kind of a failure to be detect on said circuit pattern to be inspected is a shape defect of said pattern, said electron beam irradiation energy is set within the range from 1 kV to 5 kV.

21. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the kind of a failure to be detect on said circuit pattern to be inspected is thin film remains, said electron beam irradiation energy is set within the range from 300 V to 3 kV.

22. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the kind of a failure to be detect on said circuit pattern to be inspected is all of a contact hole failure, a short defect of a transistor or line, and a pattern shape failure, said electron beam irradiation energy is set within the range from 1 kV to 5 kV.

23. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the pattern shape of said circuit pattern to be inspected is a contact hole and the step that the hole is filled with a conductor is to be inspected, said electron beam irradiation energy is set within the range from 300 V to 3 kV.

24. A circuit pattern inspection method according to any of claims 1 to 12, wherein when the pattern shape of said circuit pattern to be inspected is a contact hole and the step that the hole is not filled is to be inspected, said electron beam irradiation energy is set within the range from 800 V to 5 kV.

2. A circuit pattern inspection method including a step of scanning a board surface with a circuit pattern formed with an electron beam, a step of detecting a signal secondarily generated from said board surface by said electron beam, a step of forming an electron beam image of said board surface from said detected signal, a step of storing said electron beam image, a step of forming and storing electron beam images of areas neighboring with said board, a step of comparing said electron beam images of said two areas, and a step of deciding a failure of said circuit pattern on said board from comparison results, wherein said method identifies an item indicating the state of said circuit pattern to be inspected on an operation screen, confirms the contrast of an electron beam image corresponding to it, obtains and stores electron beam irradiation conditions including an electron beam voltage, displays said state of said circuit pattern to be inspected on said operation screen, decides said electron beam irradiation conditions using said electron beam irradiation conditions stored on said displayed screen, irradiates and scans said electron beam to said circuit pattern to be inspected under said electron beam irradiation conditions once, forms an electron beam image, and executes the inspection.

7. A circuit pattern inspection method according to claim 2 or 3, wherein the irradiation energy of said electron beam to a sample is set by a negative voltage applied to said sample and a sample carrier.

8. A circuit pattern inspection method according to claim 2 or 3, wherein the beam current of said electron beam is set by a voltage of an electrode and a current of a coil installed in an electronic optical system.

3. A circuit pattern inspection method including a step of scanning a board surface with a circuit pattern formed with an electron beam, a step of detecting a signal secondarily generated from said board surface by said electron beam, a step of forming an electron beam image of said board surface from said detected signal, a step of storing said electron beam image, a step of forming and storing electron beam images of areas neighboring with said board, a step of comparing said electron beam images of said two areas, and a step of deciding a failure of said circuit pattern on said board from comparison results, wherein said method identifies an item indicating the state of said circuit pattern to be inspected on an operation screen, confirms the contrast of an electron beam image corresponding to it, obtains and stores electron beam irradiation conditions including an electron beam voltage, displays said state of said circuit pattern to be inspected regarding the material or step of said circuit pattern to be inspected and the kind of a failure to be detected on said operation screen, and decides and executes said electron beam irradiation conditions using said electron beam irradiation conditions stored on said displayed screen.

25. A circuit pattern inspection method including a step of scanning a board surface with a circuit pattern formed with an electron beam, a step of detecting a signal secondarily generated from said board surface by said electron beam, a step of forming an electron beam image of said board surface from said detected signal, a step of storing said electron beam image, a step of forming and storing electron beam images of areas neighboring with said board in the same way, a step of comparing said electron beam images of said two areas, and a step of deciding a failure of said circuit pattern on said board from comparison results, wherein said method identifies an item indicating the state of said circuit pattern to be inspected on an operation screen, confirms the contrast of an electron beam image corresponding to it, obtains and stores electron beam irradiation conditions including an electron beam voltage, displays said state of said circuit pattern to be inspected on said operation screen, decides said electron beam irradiation conditions using said electron beam irradiation conditions stored on said displayed screen, sets alignment conditions for correcting the scanning direction of said electron beam for a semiconductor wafer to be inspected and the moving direction of a sample carrier, sets an inspection area for said semiconductor wafer to be inspected, sets calibration conditions for adjusting the brightness during inspection on the basis of said electron beam irradiation conditions, forms an electron beam image under said conditions, displays it on said screen, and executing the inspection.

26. A circuit pattern inspection device comprising an electron source for generating a primary electron beam, a lens system for focusing said primary electron beam, a sample carrier for loading a sample, transfer means for transferring a sample to a sample chamber including said sample carrier, a deflection electrode for deflecting said focused primary electron beam on said sample, a deflection signal generator for driving said deflection electrode, a secondary charged particle detector for detecting secondary charged particles generated from said sample by irradiating said primary electron beam to said sample, a first power source for applying a zero or positive voltage to said detector, an A-D converter for converting a signal from said detector to a digital signal, an image memory for forming and storing an image to be inspected on the basis of said digital signal, a comparison calculation circuit for comparing said stored image in said area with an image of another same circuit pattern, a calculation circuit for discriminating a failure on a circuit pattern from comparison results, a second power source for applying a negative voltage to said sample carrier, a control circuit for controlling said voltage applied by said second power source, a memory for building and storing a data base for various inspection conditions according to a circuit pattern to be inspected, and an operation screen and operation unit for setting said inspection conditions and executing an inspection.

27. A circuit pattern inspection device according to claim 26, wherein said device has means for applying a zero or negative potential to said sample, or said sample carrier, or the neighborhood of said sample, means for controlling said zero or negative potential and controlling energy of said electron beam to be irradiated to said board to be inspected, means for registering a potential value according to the material and shape of said circuit pattern on said sample board beforehand, and means for calling said registered conditions at the time of inspection and automatically setting said negative potential.

28. A circuit pattern inspection device according to claim 26 or 27, wherein said device has means for applying a zero or negative potential to said sample, or said sample carrier, or the neighborhood of said sample and means for adjusting a signal of said deflection electrode, said lens for focusing said electron beam, and a gain of said detector in connection with setting of said negative potential.

30. A circuit pattern inspection device according to any of claims 26 to 29, wherein said device has an operation screen for inputting a negative voltage to be applied to said sample carrier, irradiation energy of said electron beam to be irradiated to said sample, and a beam current of said electron beam to be irradiated to said sample.

31. A circuit pattern inspection device according to any of claims 26 to 30, wherein said device has a storage for registering the correspondence of information of said pattern to be inspected and inspection conditions as a database beforehand, means for inputting said conditions of said pattern to be inspected from said operation screen, and means for searching for said inspection conditions by said input and has a function for indicating a recommended value of said inspection conditions for said pattern to be inspected on the operation screen.

29. A circuit pattern inspection device comprising an electron source for generating a primary electron beam, lens means for focusing said primary electron beam, a sample carrier for loading a sample, transfer means for transferring a sample to a sample chamber including said sample carrier, primary electron beam scanning means for scanning said focused primary electron beam on said sample, means for detecting secondary charged particles secondarily generated from said sample, means for forming and storing an image on the basis of a signal from said detector, means for comparing said image in said area stored in said storage means with an image in an area in which another same circuit pattern is formed, and means for discriminating a failure on a circuit pattern from comparison results, wherein said device has means for controlling the electron beam irradiation amount according to the material or shape of said circuit pattern on said sample board and the kind of a failure to be detected.