OSA's Digital Library

Applied Optics

Applied Optics

APPLICATIONS-CENTERED RESEARCH IN OPTICS

  • Vol. 40, Iss. 16 — Jun. 1, 2001
  • pp: 2662–2669

Focus measurement with a simple pattern design

Chin-Yu Ku, Tan Fu Lei, and Hwang-Kuen Lin  »View Author Affiliations


Applied Optics, Vol. 40, Issue 16, pp. 2662-2669 (2001)
http://dx.doi.org/10.1364/AO.40.002662


View Full Text Article

Enhanced HTML    Acrobat PDF (1431 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

The increasingly smaller depth of focus of advanced lithographic tools requires that the position of best focus be determined to ensure accuracy and efficiency. We present what we believe is a novel bar in bar that is drawn on a conventional chrome binary mask to translate focal errors into center-to-center shifts of outer and inner bars. An overlay measurement tool can easily measure this shift. A symmetrical center-to-center shift against best focus is created during defocus, and this shift can be well fitted by a second-order polynomial equation. Simply differentiating the fitted equation leads to an accurate and reliable focus value, with a maximum error of less than 0.05 µm. The proposed technique can also be employed to evaluate the tilt, field curvature, and astigmatism of advanced lithographic tools.

© 2001 Optical Society of America

OCIS Codes
(110.3960) Imaging systems : Microlithography
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology

History
Original Manuscript: May 9, 2000
Revised Manuscript: February 8, 2001
Published: June 1, 2001

Citation
Chin-Yu Ku, Tan Fu Lei, and Hwang-Kuen Lin, "Focus measurement with a simple pattern design," Appl. Opt. 40, 2662-2669 (2001)
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-40-16-2662


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. S. Stalnaker, P. Luehrmann, J. Waelpoel, “Focal plane determination for sub-half micron optical steppers,” Microelectron. Eng. 21, 33–43 (1993). [CrossRef]
  2. T. A. Brunner, A. L. Martin, R. M. Martino, C. P. Ausschnitt, T. H. Newman, M. S. Hibbs, “Quantitative stepper metrology using the focus monitor test mask,” in Optical/Laser Microlighography VII, T. A. Brunner, ed., Proc. SPIE2197, 541–549 (1994). [CrossRef]
  3. W. H. Arnold, E. Barouch, U. Hollerbach, S. A. Orszag, “A focus vernier for optical lithography,” in Integrated Circuit Metrology, Inspection, and Process Control VII, M. T. Postek, ed., Proc. SPIE1926, 380–392 (1993). [CrossRef]
  4. A. D. Katnani, B. J. Lin, “Phase and transmission error study for the alternating element (Levenson) phase-shifting mask,” in Optical/Laser Microlithography V, J. D. Cuthbert, ed., Proc. SPIE1674, 264–270 (1992). [CrossRef]
  5. K. Suwa, H. Tateno, N. Irie, S. Hirukawa, “Automatic laser scanning focus detection method using printed focus pattern,” in Optical/Laser Microlithography VIII, T. A. Brunner, ed., Proc. SPIE2440, 712–720 (1995). [CrossRef]
  6. Y. C. Kim, G. S. Yeo, J. H. Lee, H. Kim, U. I. Chung, “Automatic in-situ focus monitor using line shortening effect,” in Metrology, Inspection, and Process Control for Microlithography XIII, B. Singh, ed., Proc. SPIE3677, 184–193 (1999). [CrossRef]
  7. T. A. Brunner, S. Cheng, A. E. Norton, “A stepper image monitor for precise setup and characterization,” in Fiber Optics Reliability: Benign and Adverse Environments II, R. A. Greenwell, D. K. Paul, S. G. Wadekar, eds., Proc. SPIE922, 366–375 (1988).
  8. T. A. Brunner, J. Lewis, M. Manny, “Stepper self-metrology using automated techniques,” in Optical Fibers in Medicine V, A. Katzir, ed., Proc. SPIE1201, 286–297 (1990).
  9. M. van den Brink, H. Franken, S. Wittekoek, T. Fahner, “Automatic on-line wafer stepper calibration system,” in Integrated Circuit Metrology, Inspection, and Process Control IV, W. H. Arnold, ed., Proc. SPIE1261, 298–314 (1990). [CrossRef]
  10. T. Terasawa, N. Hasegawa, T. Kurosaki, T. Tanaka, “0.3 µm optical lithography using a phase-shifting mask,” in Optical/Laser Microlithography II, B. J. Lin, ed., Proc. SPIE1088, 25–33 (1989). [CrossRef]
  11. M. D. Levenson, N. S. Viswanathan, R. A. Simpson, “Improving resolution in photolithography with a phase-shifting mask,” IEEE Trans. Electron Devices ED-29, 1828–1836 (1982). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited