EUV microexposures at the ALS using the 0.3-NA MET projection optics

Naulleau, Patrick; Goldberg, Kenneth A.; Anderson, Erik H.; Cain, Jason P.; Denham, Paul; Hoef, Brian; Jackson, Keith; Morlens, Anne-Sophie; Rekawa, Senajith; Dean, Kim

doi:10.1117/12.600388

Cited by 27 publications

(16 citation statements)

References 18 publications

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“…Furthermore, the ability to arbitrarily position the pupil fill provides for even more measurement flexibility. The programmable illuminator [4] available on the MET printing system at Berkeley [2,3] is particularly well-suited to these tasks.…”

Section: Measurement Methodsmentioning

confidence: 99%

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Lithographic characterization of low-order aberrations in a 0.3-NA EUV microfield exposure tool

Naulleau

Cain

Dean³

et al. 2006

SPIE Proceedings

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Although tremendous progress has been made in the crucial area of fabrication of extreme ultraviolet (EUV) projection optics, the realization diffraction-limited high numerical aperture (NA) optics (above 0.2 NA) remains a concern. The highest NA EUV optics available to date are the 0.3-NA Microfield Exposure Tool (MET) optics used in an experimental exposure station at Lawrence Berkeley National Laboratory [1] and commercial METs [2] at Intel and SEMATECH-North. Even though these optics have been interferometrically demonstrated to achieve diffraction-limited wavefront quality, the question remains as to whether or not such performance levels can be maintained after installation of the optics into the exposure tool.Printing-based quantitative aberration measurements provide a convenient mechanism for the characterization of the optic wavefront error in the actual lithography tool. We present the lithographic measurement of low-order aberrations in the Berkeley MET tool, including a quantitative measurement of astigmatism and spherical error and a qualitative measurement of coma. The lithographic results are directly compared to interferometry results obtained from the same optic. Measurements of the Berkeley MET indicate either an alignment drift or errors in the interferometry on the order of 0.5 to 1 nm.

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Section: Measurement Methodsmentioning

confidence: 99%

“…Sub-30 nm resolution microfield EUV lithography tools have recently been developed to enable the development of supporting technologies such as resists and masks. One such tool has been operational at Lawrence Berkeley National Laboratory since early 2004 [2,3]. The Berkeley tool relies on a synchrotron as its source of EUV radiation.…”

Section: Introductionmentioning

confidence: 99%

Lithographic characterization of low-order aberrations in a 0.3-NA EUV microfield exposure tool

Naulleau

Cain

Dean³

et al. 2006

SPIE Proceedings

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“…[1][2][3] The MET optic is composed of two multilayer-coated reflective elements and has a numerical aperture (NA) of 0.3, comparable to the value expected for first-generation EUV production tools, with a field size of 600 µm × 200 µm at the wafer.…”

Section: Introductionmentioning

confidence: 98%

Modeling of EUV photoresists with a resist point spread function

2005

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Extreme ultraviolet (EUV) lithography is under development for possible deployment at the 32-nm technology node. One active area of research in this field is the development of photoresists that can meet the stringent requirements (high resolution, high sensitivity, low LER, etc.) of lithography in this regime. In order to facilitate research in this and other areas related to EUV lithography, a printing station based upon the 0.3-NA Micro Exposure Tool (MET) optic was established at the Advanced Light Source, a synchrotron facility at Lawrence Berkeley National Laboratory.A resist modeling technique using a resist point spread function has been shown to have good agreement with experiments for certain EUV resists such as Shipley EUV-2D [2]. The resist point spread function is a two-dimensional function that, when convolved with the simulated aerial image for a given mask pattern and applied to a threshold function, gives a representation of the photoresist pattern remaining after development. The simplicity of this modeling approach makes it attractive for rapid modeling of photoresists for process development applications.In this work, the resist point spread functions for three current high-resolution EUV photoresists [Rohm and Haas EUV-2D, Rohm and Haas MET-1K (XP 3454C), and KRS] are extracted experimentally. This model is then used in combination with aerial image simulations (including effects of projection optic aberrations) to predict the resist pattern for a variety of test patterns. A comparison is made between these predictions and experimental results to evaluate the effectiveness of this modeling technique for newer high-resolution EUV resists.

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“…To validate the inspection results, printing tests of the programmed defect array were conducted using the Berkeley Micro-Exposure Tool (MET) 5 . The defect field was printed through varying focus and dose, and SEM inspection was used to determine the printability of each defect.…”

Section: Comparison With Printing In a Micro-exposure Toolmentioning

confidence: 99%