Latent image measurements in electron beam exposed polymethylmethacrylate

Shaw, Jerry C.; Rishton, S. A.; Jackson, Robert R.; O'Boyle, M.

doi:10.1063/1.104671

Cited by 6 publications

(4 citation statements)

References 10 publications

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“…While many of the bulk properties of the photochemical reaction are obtained from measurements of large area samples, 1,2 it is important to explore the changes ͑if any͒ in local resist properties induced by the exposure and subsequent processing. The development of the atomic force microscope ͑AFM͒ has allowed local surface measurements of exposure induced changes in resists [3][4][5] with sub-m scale resolution, providing information on the critical region in the exposed resist, i.e., the feature boundaries. It is the evolution of this region, during processing and development, that controls the final dimension of the structure exposed in the resist.…”

Section: ͓S0003-6951͑96͒01905-9͔mentioning

confidence: 99%

Scanning force microscopy measurements of latent image topography in chemically amplified resists

Ocola

Fryer

Reynolds

et al. 1996

Applied Physics Letters

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Section: ͓S0003-6951͑96͒01905-9͔mentioning

confidence: 99%

Scanning force microscopy measurements of latent image topography in chemically amplified resists

Ocola

Fryer

Reynolds

et al. 1996

Applied Physics Letters

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“…The development of the atomic force microscope ͑AFM͒ has allowed local surface measurements of exposure induced changes in photoresists [1][2][3][4] with sub-m scale resolution and negligible modification of the sample. This article shows a method which yields significant predevelopment information about the image formation process in x-ray, electron-beam, and UV lithography.…”

Section: Introductionmentioning

confidence: 99%

Latent image formation: Nanoscale topography and calorimetric measurements in chemically amplified resists

Ocola¹

1996

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

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The characterization of photoresists during the image formation process has traditionally relied on bulk methods during or after development. This article shows that it is not necessary to develop the photoresist in order to obtain significant information about the image formation process in x-ray, electron beam, and UV lithography. The characterization of the image formation process in chemically amplified photoresists prior to development is difficult due to their sensitivity to electrons used in scanning electron microscopy and the weak changes in dielectric constant needed for optical microscopy. The advent and development of the atomic force microscope ͑AFM͒ have allowed local surface measurements of exposure induced changed in photoresists with sub-m scale resolution and negligible modification of the sample. A series of chemically amplified resists, positive and negative, have been studied with a variety of exposure radiation ͑electron beam, x-ray, and UV͒. The results discussed in this article focus on two of these resists: SAL 605 ͑Ϫ͒, and TOK 010 ͑ϩ͒. Both positive and negative chemically amplified resists exhibit significant changes in topography and calorimetric properties during the image formation process. Interpretation of the resist topography in negative resists is given by a semi-empirical model that assumes Fickian diffusion of resist material during post-exposure bake ͑PEB͒ and verified with AFM data. The glass transition temperature, Tg, of wafer spun thin films of SAL 605 has been measured, prior to exposure, to be 75Ϯ3°C with an ellipsometric technique. The PEB temperature, 105°C, is much greater than the Tg of SAL 605, thereby providing some justification for our Fickian diffusion model. These results are preliminary until a chemical map can be done on the resist at sub-m resolution, which at present time is not possible. The need for detecting intrinsic material property changes due to the image formation process motivates the exploration of calorimetric properties of the resist. Interpretation of the calorimetric data is still unclear. Both cases of positive and negative photoresists exhibit an increase of heat absorbed in the exposed regions. Photoacid ions produced by exposure to radiation may be considered responsible for such an increase.

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“…In poly-methylmethacrylate (PMMA), e-beam exposure gives rise to byproducts in form of oxygen and carbon, which can escape the resist during the irradiation. 14,15 In turn, the irradiated film shrinks relative to the unexposed resist, and the physical compression gives access to the chemical (or latent) image of the irradiated PMMA.…”

mentioning

confidence: 99%

“…18,[20][21][22] There, however, adsorption of water and subsequent swelling of the resist can change the chemical properties of the irradiated resists. 15,21,22 Here, we introduce an in-situ AFM characterization method of 3 latent images in e-beam resists. The AFM is based on a tuning fork force sensor 23 and is fully integrated into the vacuum chamber of an e-BL-system.…”

mentioning

confidence: 99%

In situ direct visualization of irradiated electron-beam patterns on unprocessed resists using atomic force microscopy

Koop

Zech

Karraï

et al. 2010

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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The authors introduce an in situ characterization method of resists used for electron-beam lithography. The technique is based on the application of an atomic force microscope, which is directly mounted below the cathode of an electron-beam lithography system. They demonstrate that patterns irradiated by the electron beam can be efficiently visualized and analyzed in surface topography directly after the electron-beam exposure. This in situ analysis takes place without any development or baking steps and gives access to the chemical ͑or latent͒ image of the irradiated resist.

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Latent image measurements in electron beam exposed polymethylmethacrylate

Cited by 6 publications

References 10 publications

Scanning force microscopy measurements of latent image topography in chemically amplified resists

Scanning force microscopy measurements of latent image topography in chemically amplified resists

Latent image formation: Nanoscale topography and calorimetric measurements in chemically amplified resists

In situ direct visualization of irradiated electron-beam patterns on unprocessed resists using atomic force microscopy

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