Measuring and modeling the proximity effect in direct-write electron-beam lithography kinoforms

Nikolajeff, Fredrik; Bengtsson, Jörgen; Larsson, Michael; Ekberg, Mats; Hård, Sverker

doi:10.1364/ao.34.000897

Cited by 24 publications

(11 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3 shows a surface scan of a Fresnel lens before and after etching. As can been seen, already the e-beam exposed Fresnel lens shows different relief heights over the various Fresnel zones which is due to scattering of electrons when exposing the resist (proximity effect) [13]. Since the period becomes smaller (seen from the center) in a Fresnel lens, the µ-loading and angular effects are viewed well in this sort of structure.…”

Section: # ã Transfer Of the Diffractive Elementsmentioning

confidence: 94%

<title>Transfer of micro-optical structures into GaAs and diamond</title>

Karlsson

Nikolajeff

2001

SPIE Proceedings

View full text Add to dashboard Cite

Transfer of continuous-relief micro-optical structures from resist into GaAs, by use of direct-write electron-beam lithography followed by dry etching in an inductively coupled plasma, is demonstrated. A BCl 3 /Ar chemistry has been found to give satisfactory results, N 2 and Cl 2 have been added to change the selectivity between GaAs and e-beam resist. The transfer process generates smooth etched structures. Distortion of the diffractive structures in the transfer process has been examined. Blazed gratings with a period of 10 µm have been optically evaluated using a 940 nm VCSEL. The diffraction efficiency was 67% in the first order with a theoretical value of 87%. Also, simulations of the optical performance for the transfered diffractive elements have been made using Fourier transform of the grating profile. For integrating the optical element with VCSELs there are several possible alternatives. We have fabricated the optical structure on the same substrate that is used for the VCSEL and characterization is presently under way. We also show our initial results on transfer of micro-optical structures from resist into diamond using dry etching.

show abstract

Section: # ã Transfer Of the Diffractive Elementsmentioning

confidence: 94%

<title>Transfer of micro-optical structures into GaAs and diamond</title>

Karlsson

Nikolajeff

2001

SPIE Proceedings

View full text Add to dashboard Cite

show abstract

“…The noninfinitesimal dimensions of the writing spot cause a smoothing of the typical sharp-edged profile steps between the diffractive zones. 20,21 This effect becomes particularly significant at the outer regions of the lens, where the zone sizes decrease with increasing distance from the center. A simple mathematical model can be employed to estimate the resulting overall diffraction efficiency of the lens: The smoothing effect can be mathematically emulated by convolving the ideal profile with an appropriate shape function.…”

Section: Diffractive Lens Performance Simulationmentioning

confidence: 99%

Chip-level integrated diffractive optical microlenses for multimode vertical-cavity surface-emitting laser to fiber coupling

Ammer¹

2002

Opt. Eng

View full text Add to dashboard Cite

The standard assembly technologies for vertical-cavity surface-emitting laser (VCSEL) to fiber coupling systems involve the integration of discrete elements with demanding requirements for alignment effort and time. We present a method for the monolithic integration of diffractive microlenses on the chip level. This process is based on a UV-casting replication technique using ORMOCER ® (a registered trademark of Fraunhofer-Gesellschaft) materials [hybrid organic-inorganic polymers (Streppel et al. 2001)] and offers the capability to be extended to a wafer-scale process. A mathematical description for the propagation of the laser modes through the system and the resulting fiber coupling efficiency is presented. We use a model for the source characteristics of the VCSEL based on a step-index fiber model for the simulation of the mode-field propagation. A model for the estimation of the diffraction efficiency of the lens is developed. Finally the simulations are compared with first experimental results of single replicated elements. Experimental coupling efficiencies for a multimode fiber [50/125, numerical aperture (NA)ϭ0.20] better than 0.7 over the entire operation range of the VCSEL are achieved. Losses below 0.5 dB (10%) are observed within lateral fiber displacement tolerances of Ϯ10 m.

show abstract

“…To predict the electron dosage suitable for a desired profile, it is necessary to consider an electron scatter in a resist layer and resist characteristics in development process. There are some dose-correction methods taking account of the electron scatter effect and nonlinear feature of the resist development [5], [6], [7].…”

Section: Introductionmentioning

confidence: 99%

<title>Precise proximity correction for fabricating chirped diffraction gratings with direct-writing electron-beam lithography</title>

Okano¹,

Yotsuya²,

Hirai

et al. 2001

SPIE Proceedings

View full text Add to dashboard Cite

Proximity correction is an important technique to fabricate diffractive optical elements with the direct-writing electron-beam lithography. For the precise proximity correction, the absorbed energy distribution is calculated with an electron scatter simulator based on the Monte Carlo method, and a resist profile is estimated with a resist development simulator based on the cell removal model. In this paper, we calculated the optimum electron dosage for a chirped-period diffraction grating by use of such a precise proximity correction. To reduce the calculation time, we set the cell size 200nmx 200nm. The resultant resist profile, however, was much more precise than the cell size because of the interpolation. It took 24 hours to optimize the electron dosage of a grating with a width of 5mm and the minimum grating period of 4im. Moreover the grating, which was fabricated according to the calculated dosage, had a profile that agreed well with the calculated profile.

show abstract

Measuring and modeling the proximity effect in direct-write electron-beam lithography kinoforms

Cited by 24 publications

References 4 publications

<title>Transfer of micro-optical structures into GaAs and diamond</title>

<title>Transfer of micro-optical structures into GaAs and diamond</title>

Chip-level integrated diffractive optical microlenses for multimode vertical-cavity surface-emitting laser to fiber coupling

<title>Precise proximity correction for fabricating chirped diffraction gratings with direct-writing electron-beam lithography</title>

Contact Info

Product

Resources

About