Can proximity x-ray lithography print 35 nm features? Yes

Khan, Muhammad Burhan; Han, Geng; Tsvid, G.; Kitayama, Toyoki; Maldonado, Juan R.; Cerrina, F.

doi:10.1116/1.1418407

Cited by 21 publications

(16 citation statements)

References 9 publications

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“…Kahn et al have evaluated Sicontaining resist and concluded that the Si-containing resist does not provide a great improvement in resolution but it still provides 2.5 times more absorption at 2.7 keV ͑4.6 Å͒ than UV5 resist. 4,5 Here, we study the electron stopping power and secondary electron blur in Br-containing resist. We also investigate the resolution in PXL and PXL-II.…”

Section: Introductionmentioning

confidence: 99%

Suppression of secondary electron blur by using Br-containing resists in x-ray lithography

Kise

Marumoto

Watanabe

et al. 2002

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

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Second generation proximity x-ray lithography (PXL-II), which uses shorter incident x-ray wavelengths and resist materials, is expected to be a candidate for next generation lithography. In the PXL-II technique, the x-ray wavelength absorbed in the resist becomes shorter, but degradation of the pattern quality due to secondary electron blur has not been sufficiently evaluated. In this article, we present our investigation of the secondary electron blur’s suppression in Br-containing resist using a lithographic simulator and a Monte Carlo simulator for electron scattering. By introducing the Br element into resist materials, the electron stopping power improves. In addition, secondary electron blur is suppressed in regions with wavelengths shorter than that of the Br absorption edge. In order to evaluate pattern resolution, the image contrast of the lateral absorbed image in the resist is defined. We found that image contrast is improved in Br-containing resist for the wavelength range down to about 4.5 Å, which is suitable for PXL-II. We also show that it should be possible to extend PXL-II for resolutions of less than 40 nm at a narrower gap.

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Section: Introductionmentioning

confidence: 99%

Suppression of secondary electron blur by using Br-containing resists in x-ray lithography

Kise

Marumoto

Watanabe

et al. 2002

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

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“…9 In the United States, The University of Wisconsin has been studying PXL-II, and they concluded that PXL has extendibility to 35 nm. 10,11 A thick diamond membrane, which gives high transmittance in harder spectra, is one of the key materials required to realize PXL-II. We have studied the application of diamond membranes to x-ray masks jointly with Mitsubishi Materials Corporation from the viewpoints of stiffness and resultant image placement accuracy.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of high resolution x-ray masks using diamond membrane for second generation x-ray lithography

Marumoto

Yamaguchi

Aya

et al. 2003

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

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Second generation x-ray lithography (PXL-II) has been proposed to extend proximity x-ray lithography to the 50 nm generation and beyond while keeping a high throughput. Diamond membrane, which enables high power and shorter x-ray irradiation, is a key material for PXL-II. In this article, we describe the fabrication of ultrafine patterns of W–Ti absorber on thinned diamond membranes. By optimization of the etching conditions, about 30 nm W–Ti patterns with aspect ratios of about 10 were successfully fabricated. The dependence of pattern edge roughness of the absorber on the surface roughness of the diamond has also been investigated, and it has been shown that 3 nm rms roughness was enough to obtain the pattern quality equivalent to that on a SiC membrane. For narrower gap exposure with x-ray masks with thick diamond membrane in PXL-II, the flatness of the mask top surface has been studied, and we developed x-ray masks with a flatness of less than 1 μm by modifying the support ring geometry.

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“…1 Recently, other researchers 2,3 have achieved 50 nm resolution with PXL by using a 10 and 15 m gap between the mask and the wafer. Another study 4 shows that PXL can print 35 nm features using a higher energy radiation and smaller proximity gap ͑р5 m͒. Reducing the proximity gap to such a scale with standard masks however increases the risk of contact with the resist covered wafer during the positioning of the mask prior to exposure.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of x-ray masks using evaporated electron sensitive layers for back patterning of membranes

Awad¹,

Lavallée²,

Beauvais³

et al. 2002

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

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A process aimed at fabricating proximity x-ray lithography masks is presented. In this technique, the Ta absorber layer is deposited and patterned on the back side of the membrane and nonspin-coated electron sensitive layers were used in order to achieve high resolution patterning of this absorber. The advantages gained by this approach include a reduction of the membrane temperature during the plasma etching step of the absorber patterns without using any cooling gas. This temperature reduction results from the direct contact of the membrane with a cooling plate. This approach also allows increased protection of the absorber patterns from contamination during exposure of the mask. A third advantage is that the smooth surface of the mask exposed to the wafer in the x-ray lithography stepper may also make it possible to reduce the gap between wafer and mask, thus achieving increased resolution with the x-ray lithography process.

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Can proximity x-ray lithography print 35 nm features? Yes

Cited by 21 publications

References 9 publications

Suppression of secondary electron blur by using Br-containing resists in x-ray lithography

Suppression of secondary electron blur by using Br-containing resists in x-ray lithography

Fabrication of high resolution x-ray masks using diamond membrane for second generation x-ray lithography

Fabrication of x-ray masks using evaporated electron sensitive layers for back patterning of membranes

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