Abstract

In order to implement the ultraprecise measurement with large range and long working distance in confocal microscopy, confocal simultaneous phase-shifting interferometry (C-SPSI) has been presented. Four channel interference signals, with π/2 phase shift between each other, are detected simultaneously in C-SPSI. The actual surface height is then calculated by combining the optical sectioning with the phase unwrapping in the main cycle of the interference phase response, and the main cycle is deter mined using the bipolar property of differential confocal microscopy. Experimental results showed that 1nm of axial depth resolution was achieved for either low- or high-NA objective lenses. The reflectivity disturbance resistibility of C-SPSI was demonstrated by imaging a typical microcircuit specimen. C-SPSI breaks through the restriction of low NA on the axial depth resolution of confocal microscopy effectively.

© 2011 Optical Society of America

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References

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2010 (1)

L. C. Chen and Y. W. Chang, “Innovative simultaneous confocal full-field 3D surface profilometry for in situ automatic optical inspection (AOI),” Meas. Sci. Technol. 21, 065301(2010).
[CrossRef]

2009 (2)

2008 (1)

J. Cohen-Sabban, “Merging phase shifting interferometry with confocal chromatic microscopy,” Key Eng. Mater. 381–382, 287–290 (2008).
[CrossRef]

2005 (2)

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

C. Boudoux, S. Yun, W. Oh, W. White, N. Iftimia, M. Shishkov, B. Bouma, and G. Tearney, “Rapid wavelength-swept spectrally encoded confocal microscopy,” Opt. Express 13, 8214–8221 (2005).
[CrossRef] [PubMed]

2003 (1)

N. R. Sivakumar, W. K. Hui, K. Venkatakrishnan, and B. K. A. Ngoi, “Large surface profile measurement with instantaneous phase-shifting interferometry,” Opt. Eng. 42, 367–372 (2003).
[CrossRef]

2002 (2)

G. Li and Y. Fainman, “Analysis of the wavelength-to-depth encoded interference microscopy for three-dimensional imaging,” Opt. Eng. 41, 1281–1288 (2002).
[CrossRef]

J. Tan and F. Wang, “Theoretical analysis and property study of optical focus detection based on differential confocal microscopy,” Meas. Sci. Technol. 13, 1289–1293 (2002).
[CrossRef]

1997 (2)

C. H. Lee and J. Wang, “Noninterferometric differential confocal microscopy with 2 nm depth resolution,” Opt. Commun. 135, 233–237 (1997).
[CrossRef]

M. A. A. Neil, R. Juskaitis, and T. Wilson, “Method of obtaining optical sectioning by using structured light in a conventional microscope,” Opt. Lett. 22, 1905–1907 (1997).
[CrossRef]

1990 (1)

T. Wilson, Confocal Microscopy (Academic, 1990).

1989 (1)

H. J. Matthews, D. K. Hamilton, and C. J. R. Sheppard, “Aberration measurement by confocal interferometry,” J. Mod. Opt. 36, 233–250 (1989).
[CrossRef]

1987 (1)

J. G. White and W. B. Amos, “Confocal microscopy comes of age,” Nature 328, 183–184 (1987).
[CrossRef]

1984 (1)

R. Smythe and R. Moore, “Instantaneous phase measuring interferometry,” Opt. Eng. 23, 361–364 (1984).

1982 (1)

D. K. Hamilton and C. J. R. Sheppard, “A confocal interference microscope,” J. Mod. Opt. 29, 1573–1577 (1982).
[CrossRef]

Amos, W. B.

J. G. White and W. B. Amos, “Confocal microscopy comes of age,” Nature 328, 183–184 (1987).
[CrossRef]

Boudoux, C.

Bouma, B.

Brock, N.

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

Chang, Y. W.

L. C. Chen and Y. W. Chang, “Innovative simultaneous confocal full-field 3D surface profilometry for in situ automatic optical inspection (AOI),” Meas. Sci. Technol. 21, 065301(2010).
[CrossRef]

Chen, L. C.

L. C. Chen and Y. W. Chang, “Innovative simultaneous confocal full-field 3D surface profilometry for in situ automatic optical inspection (AOI),” Meas. Sci. Technol. 21, 065301(2010).
[CrossRef]

Cohen-Sabban, J.

J. Cohen-Sabban, “Merging phase shifting interferometry with confocal chromatic microscopy,” Key Eng. Mater. 381–382, 287–290 (2008).
[CrossRef]

Fainman, Y.

G. Li and Y. Fainman, “Analysis of the wavelength-to-depth encoded interference microscopy for three-dimensional imaging,” Opt. Eng. 41, 1281–1288 (2002).
[CrossRef]

Ge, Z.

Hamilton, D. K.

H. J. Matthews, D. K. Hamilton, and C. J. R. Sheppard, “Aberration measurement by confocal interferometry,” J. Mod. Opt. 36, 233–250 (1989).
[CrossRef]

D. K. Hamilton and C. J. R. Sheppard, “A confocal interference microscope,” J. Mod. Opt. 29, 1573–1577 (1982).
[CrossRef]

Hayes, J.

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

Hu, B.

Hui, W. K.

N. R. Sivakumar, W. K. Hui, K. Venkatakrishnan, and B. K. A. Ngoi, “Large surface profile measurement with instantaneous phase-shifting interferometry,” Opt. Eng. 42, 367–372 (2003).
[CrossRef]

Iftimia, N.

Juskaitis, R.

Kimbrough, B.

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

Lee, C. H.

C. H. Lee and J. Wang, “Noninterferometric differential confocal microscopy with 2 nm depth resolution,” Opt. Commun. 135, 233–237 (1997).
[CrossRef]

Li, G.

G. Li and Y. Fainman, “Analysis of the wavelength-to-depth encoded interference microscopy for three-dimensional imaging,” Opt. Eng. 41, 1281–1288 (2002).
[CrossRef]

Liu, J.

Matthews, H. J.

H. J. Matthews, D. K. Hamilton, and C. J. R. Sheppard, “Aberration measurement by confocal interferometry,” J. Mod. Opt. 36, 233–250 (1989).
[CrossRef]

Millerd, J.

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

Moore, R.

R. Smythe and R. Moore, “Instantaneous phase measuring interferometry,” Opt. Eng. 23, 361–364 (1984).

Neil, M. A. A.

Ngoi, B. K. A.

N. R. Sivakumar, W. K. Hui, K. Venkatakrishnan, and B. K. A. Ngoi, “Large surface profile measurement with instantaneous phase-shifting interferometry,” Opt. Eng. 42, 367–372 (2003).
[CrossRef]

North-Morris, M.

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

Novak, M.

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

Oh, W.

Sheppard, C. J. R.

H. J. Matthews, D. K. Hamilton, and C. J. R. Sheppard, “Aberration measurement by confocal interferometry,” J. Mod. Opt. 36, 233–250 (1989).
[CrossRef]

D. K. Hamilton and C. J. R. Sheppard, “A confocal interference microscope,” J. Mod. Opt. 29, 1573–1577 (1982).
[CrossRef]

Shishkov, M.

Sivakumar, N. R.

N. R. Sivakumar, W. K. Hui, K. Venkatakrishnan, and B. K. A. Ngoi, “Large surface profile measurement with instantaneous phase-shifting interferometry,” Opt. Eng. 42, 367–372 (2003).
[CrossRef]

Smythe, R.

R. Smythe and R. Moore, “Instantaneous phase measuring interferometry,” Opt. Eng. 23, 361–364 (1984).

Tan, J.

Tearney, G.

Venkatakrishnan, K.

N. R. Sivakumar, W. K. Hui, K. Venkatakrishnan, and B. K. A. Ngoi, “Large surface profile measurement with instantaneous phase-shifting interferometry,” Opt. Eng. 42, 367–372 (2003).
[CrossRef]

Wang, F.

J. Tan and F. Wang, “Theoretical analysis and property study of optical focus detection based on differential confocal microscopy,” Meas. Sci. Technol. 13, 1289–1293 (2002).
[CrossRef]

Wang, J.

C. H. Lee and J. Wang, “Noninterferometric differential confocal microscopy with 2 nm depth resolution,” Opt. Commun. 135, 233–237 (1997).
[CrossRef]

Wang, Y.

White, J. G.

J. G. White and W. B. Amos, “Confocal microscopy comes of age,” Nature 328, 183–184 (1987).
[CrossRef]

White, W.

Wilson, T.

Wyant, J. C.

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

Yun, S.

Zhang, D.

Zhao, C.

Appl. Opt. (1)

J. Mod. Opt. (2)

D. K. Hamilton and C. J. R. Sheppard, “A confocal interference microscope,” J. Mod. Opt. 29, 1573–1577 (1982).
[CrossRef]

H. J. Matthews, D. K. Hamilton, and C. J. R. Sheppard, “Aberration measurement by confocal interferometry,” J. Mod. Opt. 36, 233–250 (1989).
[CrossRef]

Key Eng. Mater. (1)

J. Cohen-Sabban, “Merging phase shifting interferometry with confocal chromatic microscopy,” Key Eng. Mater. 381–382, 287–290 (2008).
[CrossRef]

Meas. Sci. Technol. (2)

J. Tan and F. Wang, “Theoretical analysis and property study of optical focus detection based on differential confocal microscopy,” Meas. Sci. Technol. 13, 1289–1293 (2002).
[CrossRef]

L. C. Chen and Y. W. Chang, “Innovative simultaneous confocal full-field 3D surface profilometry for in situ automatic optical inspection (AOI),” Meas. Sci. Technol. 21, 065301(2010).
[CrossRef]

Nature (1)

J. G. White and W. B. Amos, “Confocal microscopy comes of age,” Nature 328, 183–184 (1987).
[CrossRef]

Opt. Commun. (1)

C. H. Lee and J. Wang, “Noninterferometric differential confocal microscopy with 2 nm depth resolution,” Opt. Commun. 135, 233–237 (1997).
[CrossRef]

Opt. Eng. (3)

R. Smythe and R. Moore, “Instantaneous phase measuring interferometry,” Opt. Eng. 23, 361–364 (1984).

N. R. Sivakumar, W. K. Hui, K. Venkatakrishnan, and B. K. A. Ngoi, “Large surface profile measurement with instantaneous phase-shifting interferometry,” Opt. Eng. 42, 367–372 (2003).
[CrossRef]

G. Li and Y. Fainman, “Analysis of the wavelength-to-depth encoded interference microscopy for three-dimensional imaging,” Opt. Eng. 41, 1281–1288 (2002).
[CrossRef]

Opt. Express (2)

Opt. Lett. (1)

Proc. SPIE (1)

N. Brock, J. Hayes, B. Kimbrough, J. Millerd, M. North-Morris, M. Novak, and J. C. Wyant, “Dynamic interferometry,” Proc. SPIE 5875, 58750F (2005).
[CrossRef]

Other (1)

T. Wilson, Confocal Microscopy (Academic, 1990).

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Figures (8)

Fig. 1
Fig. 1

Schematic diagram of C-SPSI. 1, laser; 2, 18, 20, mirror; 3, converging lens; 4, illuminating pinhole; 5, collimating lens; 6, 14, half-wave plate (HWP); 7, 17, 19, polarizing beam splitter (PBS); 8, 12, 16, quarter-wave plate (QWP); 9, objective lens; 10, specimen; 11, precision translation stage; 13, reference mirror; 15, nonpolarizing beam splitter (NPBS); 21, 22, 23, 24, collector lens; 25, 26, 27, 28, single-mode fiber; 29, 30, 31, 32, photodetector.

Fig. 2
Fig. 2

Theoretical curves of differential intensity and phase signals (a)  I inten and (b)  I phase , respectively.

Fig. 3
Fig. 3

Comparison of defocused intensity and phase signals.

Fig. 4
Fig. 4

FWHM of the axial intensity for C-SPSI compared with that for conventional confocal microscopy.

Fig. 5
Fig. 5

Experimental setup of the integrated C-SPSI measurement system.

Fig. 6
Fig. 6

Comparison of the axial depth resolution of C-SPSI with various objective lenses: (a)  NA = 0.25 , (b) 0.4, (c) 0.65, and (d) 0.9.

Fig. 7
Fig. 7

Reflectivity contrast between metal and dielectric surfaces.

Fig. 8
Fig. 8

Local measurement results of the microcircuit specimen obtained by (a) conventional wide-field microscope and (b) C-SPSI corresponding to the highlighted square in (a).

Equations (12)

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E r = R · exp ( i φ r ) ,
E m ± u d ( u ) = S · sinc ( 2 u ± u d 4 π ) · exp [ i φ m ( u ) ] ,
u = 8 π λ z sin 2 ( θ / 2 ) ,
u d = 8 π λ z d sin 2 ( θ c / 2 ) ,
I ± u d ( u ) = | E r | 2 + | E m ± u d ( u ) | 2 + 2 Re { E r * · E m ± u d ( u ) } = I d ± u d ( u ) + I a ± u d ( u ) cos [ Δ φ ( u ) ] ,
I d ± u d ( u ) = R 2 + S 2 · sinc 2 ( 2 u ± u d 4 π ) ,
I a ± u d ( u ) = 2 R · S · sinc ( 2 u ± u d 4 π ) .
I A ( u ) = I d u d ( u ) + I a u d ( u ) · cos [ Δ φ ( u ) ] , I B ( u ) = I d u d ( u ) + I a u d ( u ) · cos [ Δ φ ( u ) + π ] = I d u d ( u ) I a u d ( u ) · cos [ Δ φ ( u ) ] , I C ( u ) = I d + u d ( u ) + I a + u d ( u ) · cos [ Δ φ ( u ) + π / 2 ] = I d + u d ( u ) + I a + u d ( u ) · sin [ Δ φ ( u ) ] , I D ( u ) = I d + u d ( u ) + I a + u d ( u ) · cos [ Δ φ ( u ) + 3 π / 2 ] = I d + u d ( u ) I a + u d ( u ) · sin [ Δ φ ( u ) ] .
I inten ( u ) = [ I C ( u ) + I D ( u ) ] [ I A ( u ) + I B ( u ) ] = 2 S 2 [ sinc 2 ( 2 u + u d 4 π ) sinc 2 ( 2 u u d 4 π ) ] ,
I phase ( u ) = I C ( u ) I D ( u ) I A ( u ) I B ( u ) = K u d ( u ) · tan [ Δ φ ( u ) ] ,
K u d ( u ) = sinc ( 2 u u d 4 π ) / sinc ( 2 u + u d 4 π ) .
z = m · δ + z m ,

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