X-ray lithography for ⩽100 nm ground rules in complex patterns

Hector, Scott Daniel; Pol, Victor; Krasnoperova, Azalia A.; Maldonado, Juan R.; Flamholz, A.; Heald, Dave; Stahlhammer, Carl; Galburt, D.; Amodeo, R. J.; Donohue, T.P.; Wind, Shalom J.; Buchigniano, James; Viswanathan, R.; Khan, Muhammad Burhan; Bollepalli, Srinivas B.; Cerrina, F.

doi:10.1116/1.589677

Cited by 20 publications

(6 citation statements)

References 12 publications

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“…The optimal wavelength range for X-ray lithography is dependent on resist sensitivity, mask transparency, and diffraction effects 85 and is usually regarded to be between 0.8 and 1.4 nm . At wavelengths this short, even the all-reflective optical systems used in EUV are not practical, hence proximity printing is the only alternative.…”

Section: Proximity X-raymentioning

confidence: 99%

Lithographic Imaging Techniques for the Formation of Nanoscopic Features

1999

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Over the past 30 years the world market for semiconductors has grown at an average annual rate of approximately 15%. This growth has been maintained by the industry's unique ability to consistently provide over this time frame higher device performance at lower cost (achieving a 25-30% per-year cost reduction per function). Microlithography is the key technological driving force for this; in large part, the overall rate of progress in microelectronics is controlled by the rate of advances in microlithographic tools, methods, and materials. Today, the photolithographic technologies that have served the microelectronics community since its inception are widely viewed to be nearing their limits of extendibility. If the historical growth rate is to be maintained in the future, new imaging technologies with the capability of forming features with sub-100 nm dimensions must be devised and refined. In this paper we provide an overview of the issues to be considered for patterning in the sub-100 nm regime and describe the imaging technologies which are currently being evaluated for such use.

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Section: Proximity X-raymentioning

confidence: 99%

Lithographic Imaging Techniques for the Formation of Nanoscopic Features

1999

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“…At the NTT facility it has been demonstrated that a 55 nm lines and spaces ͑L/S͒ pattern can be printed with a mask-wafer gap of 10 m. 7 The conclusion is that these systems can be applied to the 70 nm generation, but not so easily to the 50 nm generation. 8 We now consider an illumination system to deliver exposure light in the short wavelength down to around 3 Å. ASET has recently introduced a flash exposure system, XRA-1000 by Canon, based on the aspherical mirror with a 1°grazing angle, as shown in Fig. 3.…”

Section: Proposal For a 50 Nm Pxrl Systemmentioning

confidence: 99%

Proposal for a 50 nm proximity x-ray lithography system and extension to 35 nm by resist material selection

Kitayama

Itoga

Watanabe

et al. 2000

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

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In this article, a 50 nm generation proximity x-ray lithography ͑PXRL͒ system is proposed using shorter wavelengths of exposure light down to around 3 Å. The illumination system uses a mirror at 1°incidence angle such as in the Canon stepper XRA-1000, which can be realized by coating with a fourth or fifth period metal such as Co or Rh. The resist containing chemical elements such as Cl, S, P, Si, and Br whose x-ray absorption edge lies in the wavelength band of the exposure light can yield a strong absorption using this system. Therefore, a resist material containing such elements is highly sensitive when applied to the 50 nm system. The average wavelength of power absorbed by the resist depends on the elements contained in the resist. This suggests that the resolution limits also depend on the resist material even for the same exposure system. Therefore, this system should be extendible down to the 35 nm generation by using such a resist and a thick diamond mask membrane. The system described assumes that the mask-wafer gap is the currently available 10 m. In the future, an additional gain in resolution can be expected from a narrower gap. With these improvements, it is foreseeable that PXRL technology can be applied to the 20 nm regime, down to the operational limits of silicon devices at room temperature.

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“…The effects of diffraction on two-dimensional patterns are of particular interest; for example, some line end shortening has been observed, 23 although it is generally much smaller than what is observed in optical lithography today, and studies with negative resist 24 suggest that it may be insignificant with such systems. There is therefore increased interest in understanding the applicability of XRL at ground rules down to 70 nm, and studies are in progress to supplement those done previously.…”

Section: Resistmentioning

confidence: 99%

Challenges and progress in x-ray lithography

Silverman

1998

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

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X-ray lithography ͑XRL͒ is a very promising technique with the potential to be available for integrated circuit manufacturing as early as the 130 nm generation. As a result of many years of development, the technology is relatively mature. Synchrotron sources have demonstrated performance and reliability; preproduction aligners are available from multiple vendors; significant improvements are being made in mask fabrication; and high resolution imaging has been demonstrated at 100 nm and below. Established vendors already have experience with almost all of the tools that are needed, although improved performance is required for most in order to satisfy the error budgets at 130 nm and below. Significant development activities are continuing in both the United States and Japan, and numerous complex integrated circuits have been fabricated using XRL for one or more critical levels. Nonetheless, there are challenges still to be met. Among the most important are the development and commercial availability of an improved e-beam mask writer; the ability to fabricate defect-free masks satisfying the image placement and critical dimension control requirements with good yields; the stability of the masks in usage ͑including the issue of possible radiation damage͒; the ability to correct for magnification errors; and the ability to satisfy the industry's desire for a technology extendible to 70 nm ground rules. These issues are primarily manufacturing issues, as opposed to issues related to demonstrating proof-of-concept or feasibility, although demonstrating extendibility is still needed before the industry can commit to using XRL at 70 nm ground rules. Because of the existing XRL facilities and experience, effective work to address these and other issues can be accomplished in a timely manner.

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X-ray lithography for ⩽100 nm ground rules in complex patterns

Cited by 20 publications

References 12 publications

Lithographic Imaging Techniques for the Formation of Nanoscopic Features

Lithographic Imaging Techniques for the Formation of Nanoscopic Features

Proposal for a 50 nm proximity x-ray lithography system and extension to 35 nm by resist material selection

Challenges and progress in x-ray lithography

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