Abstract

A simultaneous volumetric thickness-profile measurement method based on an acousto-optic tunable filter for transparent film deposited upon pattern structures is described. The nondestructive thickness profilometer prevents the destruction of samples such as one encounters in using a scanning-electron microscope and provides good accuracy. The information on the volumetric thickness profile is obtained through least-squares fitting with a phase model, ϕmodelk=2kh+ψk,d+(offset), which has three unknowns: surface profile h, thickness d, and an indeterminate initial phase offset. Accurate phase information in the spectral domain can be obtained by introduction of the concept of spectral carrier frequency. Experimental results for a metal patterned sample show that the volumetric thickness profile can be determined within an error range of 10 nm.

© 2002 Optical Society of America

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References

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  1. P. de Groot and L. Dech, Opt. Lett. 18, 1462 (1993).
    [CrossRef] [PubMed]
  2. J. Schwider and L. Zhou, Opt. Lett. 19, 995 (1994).
    [CrossRef] [PubMed]
  3. U. Schnell and R. Dandliker, Opt. Lett. 21, 528 (1996).
    [CrossRef] [PubMed]
  4. P. Sandoz, G. Tribillon, and H. Perrin, J. Mod. Opt. 43, 701 (1996).
    [CrossRef]
  5. P. Hariharan and R. Maitreyee, J. Mod. Opt. 43, 1979 (1996).
  6. S. W. Kim and G. H. Kim, Appl. Opt. 38, 5968 (1999).
    [CrossRef]
  7. M. Takeda, H. Ina, and S. Kobayashi, J. Opt. Soc. Am. 72, 156 (1982).
    [CrossRef]
  8. The Levenberg–Marquardt algorithm is available as the lsqnonlin function by a commerical S/W MATLAB.

1999 (1)

1996 (3)

U. Schnell and R. Dandliker, Opt. Lett. 21, 528 (1996).
[CrossRef] [PubMed]

P. Sandoz, G. Tribillon, and H. Perrin, J. Mod. Opt. 43, 701 (1996).
[CrossRef]

P. Hariharan and R. Maitreyee, J. Mod. Opt. 43, 1979 (1996).

1994 (1)

1993 (1)

1982 (1)

Appl. Opt. (1)

J. Mod. Opt. (2)

P. Sandoz, G. Tribillon, and H. Perrin, J. Mod. Opt. 43, 701 (1996).
[CrossRef]

P. Hariharan and R. Maitreyee, J. Mod. Opt. 43, 1979 (1996).

J. Opt. Soc. Am. (1)

Opt. Lett. (3)

Other (1)

The Levenberg–Marquardt algorithm is available as the lsqnonlin function by a commerical S/W MATLAB.

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Figures (4)

Fig. 1
Fig. 1

Schematic diagram of the proposed AOTF-based volumetric thin-film thickness profile measurement system, showing dx,y and hx,y. SMF, single-mode fiber.

Fig. 2
Fig. 2

Photo of the aluminum patterned sample and a view along points A and A with a SEM.

Fig. 3
Fig. 3

Measured phase function ϕmeasuredk and result of phase model fitting.

Fig. 4
Fig. 4

Results of volumetric thickness profile measurement of the aluminum pattern sample.

Tables (1)

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Table 1 Results of Thin-Film Thickness Profile Measurements

Equations (7)

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Ix,y,k,h,d=Erx,y,k+Etx,y,k,h,d2=i0k,d1+γk,dcosϕk,h,d,
ψk,d=arctanB/A,
R=r01+r12 exp-j2 dNkk1+r01r12 exp-j2 dNkk=A+Bj.
Ik=ak+bkcosϕk+2kh0=ak+ckexp2kh0j+c*kexp-2kh0j,
ck=½bkexpϕkj.
Ifk=Afk+Cfk-h0+C*fk+h0,
ηh,d,offset=i=1nϕmodelki,h,d,offset-ϕmeasuredki2.

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