Synchrotron radiation micro-Fourier transform infrared spectroscopy applied to photoresist imaging

Ocola, Leonidas E.; Cerrina, F.; May, Tim

doi:10.1063/1.119665

Cited by 8 publications

(6 citation statements)

References 11 publications

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“…Although the photoresist edge is sharp, the profiles are broadened in all cases, with the degree of broadening increasing with wavelength as expected from diffraction. Similar results have been reported by Ocola et al 6 As noted above, the measured profile is a convolution of the illumination function I with the actual edge profile. Assuming the edge is perfectly abrupt, one can deconvolve the data to produce the pattern of illumination transverse to the narrow slit aperture, in this case I(x).…”

Section: Measurementssupporting

confidence: 82%

“…3 The high brightness of this source ͑two to three orders of magnitude greater than conventional thermal sources͒ allows one to set the instrument's apertures to define geometrical areas comparable to, or smaller than, the diffraction limit ͑a few microns in the mid-infrared͒ and still attain good signal to noise ͑S/N͒. [4][5][6] For this situation, the spatial resolution is no longer controlled by the geometrical aperture size, but instead is determined by the optical system's numerical aperture and the wavelength of light.…”

Section: Introductionmentioning

confidence: 99%

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Resolution limits for infrared microspectroscopy explored with synchrotron radiation

Carr

2001

Review of Scientific Instruments

217

179

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The spatial resolution for infrared microspectroscopy is investigated to determine the practical limits imposed by diffraction or optical aberrations. Quantitative results are obtained using high brightness synchrotron radiation, which serves as a diffraction-limited infrared “point source” for the microscope. The measured resolving power is in good agreement with diffraction theory, including a ∼ 30% improvement for a confocal optical arrangement. The diffraction calculation also shows how the confocal setup leads to better image contrast. The full width at half maximum of the instrument’s resolution pattern is approximately λ/2 for this arrangement. One achieves this diffraction limit when the instrument’s apertures define a region having dimensions equal to the wavelength of interest. While commercial microspectrometers are well corrected for optical aberrations (allowing diffraction-limited results), the standard substrates used for supporting specimens introduce chromatic aberrations. An analysis of this aberration is also presented, and correction methods described.

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Section: Measurementssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Resolution limits for infrared microspectroscopy explored with synchrotron radiation

Carr

2001

Review of Scientific Instruments

217

179

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“…8 The sample, IR microscope optics, and stage components were confined in a specially designed enclosure to provide a controlled atmosphere of flowing nitrogen. 3 at the Aladdin synchrotron ͑Stoughton, WI͒.…”

Section: Methodsmentioning

confidence: 99%

Latent image characterization of postexposure bake process in chemically amplified resists

Ocola

Cerrina

May

1997

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Resolution blur of latent acid image and acid generation efficiency of chemically amplified resists for electron beam lithography J. Appl. Phys. 99, 054509 (2006); 10.1063/1.2173689Real-time Fourier transform infrared spectroscopy study of the kinetics of acid-catalyzed negative-tone resists based on hexamethoxymethylmelamine and phenolic resinsThe demand of smaller device dimensions drives the need to improve the lithographic and the metrology tools to produce them. Characterization of the image formation during the lithography process is key to any process control effort. Scanning probe microscopy ͑SPM͒ on exposed, unbaked and baked, undeveloped photoresist shows morphological details of the image formation process unachievable with other techniques. The use of micro-Fourier transform infrared ͑-FTIR͒ spectroscopy will be investigated for latent image chemical analysis. Both of these techniques will be used in the study of the dependence of the latent image of a negative novolac-based chemically amplified resist, SAL 605 ͑Shipley͒, with postexposure bake ͑PEB͒ conditions. The objective of the experiment is to understand how the thermal properties of the resist and the linking reaction taking place are related to each other during PEB. Experimental results indicate that resist from unexposed regions diffuse into the exposed resist during PEB. SPM results show that this diffusion increases as the PEB temperature rises above the glass transition temperature of the unexposed resist. -FTIR results show that the linker component of the resist, hexamethoxymethylmelamine, has been identified as one of the resist components that diffuses into the exposed regions during PEB.

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“…The utilization of synchrotron radiation ͑SR͒ as an alternative to traditional thermal radiation sources in infrared spectroscopy has been documented by several research groups. [1][2][3][4][5][6] Beginning with the Daresbury Synchrotron Radiation Source in the UK, a substantial number of infrared beamlines have been built in the last 20 yr at synchrotron facilities in several countries; more are planned or already under development. Many of these beamlines are dedicated to infrared microspectroscopy, and are designed to take advantage of the intrinsically high radiance ͑radiant power per unit area per unit solid angle͒ of SR in the mid-infrared.…”

Section: Introductionmentioning

confidence: 99%

Synchrotron infrared photoacoustic spectroscopy

Michaelian

Jackson

Homes

2001

Review of Scientific Instruments

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The use of synchrotron radiation ͑SR͒ as a far-and mid-infrared source in the measurement of photoacoustic Fourier transform infrared spectra of solids is demonstrated for the first time in this work. Initial experiments were performed at beamline U10A at the National Synchrotron Light Source, Brookhaven National Laboratory. For synchrotron photoacoustic spectroscopy to be feasible, it must yield results superior to those obtained with a conventional thermal ͑Globar ® ͒ source; accordingly, SR and Globar ® photoacoustic spectra recorded under similar conditions were compared in detail. The intensities of SR far-infrared photoacoustic spectra were found to be consistently greater than the corresponding Globar ® spectra. At shorter wavelengths, SR always underfills the effective aperture ͑or, alternately, sample size͒; SR is a superior source in a spectral region that is a function of this aperture. The high wave number limit of this region exhibits a power-law dependence on aperture size. This investigation also showed that the entire mid-infrared photoacoustic spectrum is more intense using SR and apertures smaller than approximately 0.5 mm.

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Synchrotron radiation micro-Fourier transform infrared spectroscopy applied to photoresist imaging

Cited by 8 publications

References 11 publications

Resolution limits for infrared microspectroscopy explored with synchrotron radiation

Resolution limits for infrared microspectroscopy explored with synchrotron radiation

Latent image characterization of postexposure bake process in chemically amplified resists

Synchrotron infrared photoacoustic spectroscopy

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