X-Ray Lithography with a Wet-Silylated and Dry-Developed Resist

A wet-silylated and dry-developed resist process for proximity X-ray and broad-band EUV (13-4O nm) lithographies is investigated in order to overcome pattern collapse during wet development and to delineate finepitch and high-aspect-ratio patterns. In addition, the applicability to sub-0.1-µm patterning is discussed. Imaging experiments for proximity X-ray lithography are performed using a synchrotron radiation (SR) light source from the beamline (BL-A1) at the SORTEC ring, and those for broad-band EUV lithography are performed using 32:1 reduction Schwarzschild optics illuminated with the SR light source from the beamline (BL-D2). The silylation solution consists of B[DMA]DS (bis(dimethylamino)dimethylsilane) or HMCTS (hexamethylcyclotrisilazane) as the silylatiog agent, MCA (methyl cellosolve acetate) as the diffusion promoter and a solvent xylene. Silylation characterization and determination of the optimum composition of the silylation solution have been performed using Fourier transform infrared spectroscopy (FTIR) measurement. Using the optimal wet-silylation and dry-developed resist system, 0.08-µm lines and spaces of a 0.5-µm-thick resist (aspect ratio = 6) in proximity X-ray lithography, and 0.1-µm lines and spaces of a 0.55-µm-thick resist (aspect ratio = 5.5) in broad-band EUVL can be successfully delineated. High resolutions of <_0.1 µm show that the silylation process for proximity X-ray and EUV lithographies is applicable to sub-0.l-µm lithography with a single-resist scheme.

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“…Characterization and optimization of silylation process FTIR spectra of the resists after silylation and 02 RIE [12] are shown in Fig. 4.…”

Section: Resultsmentioning

confidence: 99%

Wet-silylation Process for X-ray and EUV Lithographies.

Oizumi

Yamashita²,

Ogawa

et al. 1996

J. Photopol. Sci. Technol.

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“…The high aspect ratio in the replication process can be obtained by soft x-ray exposure followed by wet development, 15 or a wet-silylated and dry development resist. 16 Collapse of the developed polymethyl methacrylate (PMMA) rings under the superficial tension forces during drying or wetting the sample are known to be a major cause of failure. Thus, a wet process to exclude the drying procedure between the initial resist development and the final Au electroplating was developed.…”

Section: Introductionmentioning

confidence: 99%

Progress in the fabrication of high-aspect-ratio zone plates by soft x-ray lithography

et al. 2002

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Fabrication of Fresnel zone plates for the hard x-ray spectral region combines the challenge of high lateral resolution (~100 nm) with a large thickness requirement for the phase-shifting material (0.5-3 µm). For achieving a high resolution, the initial mask was fabricated by e-beam lithography and gold electroforming. To prevent the collapse of the structures between the developing and electroforming processes, drying was completely eliminated. Fabrication errors, such as nonuniform gold electroplating and collapse of structures, were systematically analyzed and largely eliminated. We optimized the exposure and developing processes for 950k and 2200k polymethylmethacrylate of different thicknesses and various adhesion promoters. We discuss the effects of these fabrication steps on the zone plate's resolution and aspect ratio. Fresnel zone plates with 110 nm outermost zone width, 150 µm diameter, and 1.3 µm gold thickness were fabricated. Preliminary evaluation of the FZPs was done by scanning electron microscopy and atomic force microscopy. The FZP focusing performance was characterized at the Advanced Photon Source at Argonne National Laboratory.

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“…To minimize the resist pattern collapse, the use of a low-surface-tension rinse liquid, or a rigid and highly adhesive resist material can be employed to improve the aspect ratio of dense patterns to 6. An aspect ratio of 6 can be also reached with flood exposure during rinse process [6] , or a wet-silylated and dry-development resist [7].…”

Section: Introductionmentioning

confidence: 99%

0.1-μm high-aspect-ratio pattern replication and linewidth control

et al. 1998

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The process for replication of high aspect ratio Au patterns typically includes X-ray lithography, RIE and electroplating. In this paper a study of linewidth of dense L/S patterns in a wide a range of periods is undertaken through the replication process. Effects of exposure dose, mask-wafer gap, RIE and electroplating process parameters on linewidth are addressed. We found that RIE parameters are the main factor affecting the linewidth. Based on the results of this study, we propose to introduce a bias in the mask pattern to compensate the linewidth changes occurring during subsequent replication steps. Most interestingly, a mask with a required bias can also be produced by a self-biased process. Bias adjustment has been demonstrated for 0.1/0.1 jm L/S features with aspect ratio of6. To further increase aspect ratio, a wet process is developed.An aspect ratio of 9 is achieved for 0. 1 m Au L/S patterns by using the wet process. With this method, the linewidth fidelity during replication is substantially improved.

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X-Ray Lithography with a Wet-Silylated and Dry-Developed Resist

Cited by 4 publications

References 11 publications

Wet-silylation Process for X-ray and EUV Lithographies.

Wet-silylation Process for X-ray and EUV Lithographies.

Progress in the fabrication of high-aspect-ratio zone plates by soft x-ray lithography

0.1-μm high-aspect-ratio pattern replication and linewidth control

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