Benefits and limitations of immersion lithography

Mulkens, Jan; Flagello, Donis G.; Streefkerk, Bob; Gräupner, Paul

doi:10.1117/1.1636768

Cited by 27 publications

(5 citation statements)

References 15 publications

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“…The major change from dry to immersion is reduction of the working distance to utilize the short optical distance required to minimize the effect of inhomogeneity. However, when NA >1 is required, the bending angles in the lens are harder to manage 14,15 . At n cm =1.44, the design limit appears to be 1.3~1.35 by some lens designers 18 .…”

Section: The Immersion Lensmentioning

confidence: 98%

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Immersion lithography and its impact on semiconductor manufacturing

Lin

2004

SPIE Proceedings

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ArF lithography is approaching its limit past the 90-nm node. F 2 lithography using 157-nm light seems to be a natural extension to the next node. However, several key problems in F 2 lithography are still insurmountable. The thin-film pellicle material cannot withstand more than 10 exposures. The hard pellicle technology is far from manufacture-worthy. Ditto for the F 2 resist systems. Despite great progresses made, the CaF 2 material still suffers from quality and quantity problems. On the other hand, ArF lithography using water immersion between the front lens element and the photoresist, effectively reduces the 193-nm wavelength to 135 nm and opens up rooms for improvement in resolution and depth of focus (DOF). This paper gives a systematic examination of immersion lithography. It analyses and evaluates the diffraction DOF, required DOF, and available DOF in a dry and an immersion system. It also analyses the effects of polarization to dry and immersion imaging. These phenomena are included in simulations to study the imaging of critical layers such as Poly, Contact, and Metal layers for the 65-nm, 45-nm, and 32-nm nodes using 193-nm and 157-nm, dry and immersion systems. The imaging feasibility of 157-nm immersion to the 22-nm node is briefly studied. In additions to the imaging comparison, the impacts and challenges to employ these lithography systems will also be covered. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/15/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Proc. of SPIE Vol. 5377 49 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/15/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Proc. of SPIE Vol. 5377 51 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/15/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

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Section: The Immersion Lensmentioning

confidence: 98%

“…The lens-based configuration (LBC) is also known as the shower configuration 14,15 . As shown in Figure 8, immersion fluid is applied to and extracted from a small region covering the lens and is stationary with respect to the lens as the wafer is stepped or scanned.…”

Section: Lens-based Configurationmentioning

confidence: 99%

Immersion lithography and its impact on semiconductor manufacturing

Lin

2004

SPIE Proceedings

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“…5 In a double-patterning approach with high-index methods, half pitches approaching 16 nm were anticipated with the most aggressive k1 reductions. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] High-index immersion was considered as an alternative next technology until the fall of 2008, when the development of the required materials and technology was stopped by the main scanner vendors, and the focus shifted toward double patterning for 32-nm node and EUV lithography for the 22-nm node. Whereas EUV has shown the required high resolution on full wafer, its readiness to produce at acceptable cost of ownership still has to be demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Fluid-photoresist interactions and imaging in high-index immersion lithography

Tran

Hendrickx

Roey

et al. 2009

J. Micro/Nanolith. MEMS MOEMS

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Optical immersion lithography using fluids with refractive indices greater than that of water ͑1.436͒ can enable numerical apertures of 1.55 or above for printing sub-45-nm lines. Two second-generation immersion fluid candidates, IF132 and IF169, both have indices above 1.64 and have been optimized to absorb less than 0.1 cm −1 at 193.4 nm. These fluids, although meeting the requirements of index and absorption, must also be compatible with current resists and processes to image the required fine line patterns. Results of fluid-resist interactions, with water and high-index fluids on four commercial resists, are shown. Photoacid generator ͑PAG͒ leaching measurements reveal much less leaching into both high-index fluids than into water, and in two waterimmersion dedicated resists, no leaching is detected with the high-index immersion fluids. Little resist thickness change and swelling is detected by a quartz crystal microbalance ͑QCM͒ on contact with the fluids. Resist profile and line height changes due to pre-and postexposure fluid contact varies from one resist to the next, but overall the changes are minimal. Misting defects from high-index fluid-resist contact show lower counts than for water, and imaging on an immersion interference printer produces 36-nm half-pitch lines. We find no serious impediments to the use of high-index liquids based on these results.

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“…However, the highest magnification water immersion objective lens from Nikon has NA ∼1.1 and is not designed for near UV; (c) immersion oil has a refractive index that better matches with glasses and photoresists (∼1.6) [7], which facilitate the control of stray light generation [8][9][10] from the interface of the lens and media, and is especially important in our digital lithography system using designs of an infinitely corrected microscope. A high contrast ratio is a requirement to achieve consistent results with our digital lithography system; (d) the low viscosity of water compared with the immersion oil also requires the implementation of an elaborate liquid supply and recovery [11], whereas a static application of the oil layer is sufficient to perform a scanning lithography for immersion oil. Additionally immersion oil does not dry out during the prolonged time it takes to perform a large area fabrication; (e) the depth of field (DOF) for an oil immersion objective with NA 1.25 is 372 nm and the DOF for a water immersion objective with the same NA is 320 nm at a 385 nm wavelength as given by the expression [12]:…”

mentioning

confidence: 99%

“…Therefore, this research focuses on using an oil immersion objective lens commonly used for bright-field bio-medical imaging to further improve the digital scanning lithography. Immersion oil can increase the effective NA of the objective lens and the associated resolution in light projection/imaging [6,11,13]. It was expected that around a three times improvement in the optical resolution can be achieved when an NA = 1.25 oil immersion objective lens is used in our digital scanning photolithography system.…”

mentioning

confidence: 99%

Scanning digital oil immersion lithography providing high-speed large area patterning with diffraction limited sub-micron resolution

Jakkinapalli¹,

Bhaskar²,

Wen³

2020

J. Micromech. Microeng.

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A high numerical aperture (NA) scanning digital oil immersion lithography scheme is proposed and demonstrated in this study. To successfully conduct the scanning digital oil immersion lithography, immersion oil should be removed from the photoresist layer before the development process. Also, uniformity of the projected light patterns becomes crucial in the quality of this high NA photolithography. To solve these issues, we developed a cleaning procedure for the immersion oil and an intensity calibration scheme to achieve a highly uniform intensity distribution of the projected patterns. With these preparations, we were able to achieve 400 nm resolution large area patterning with the developed scanning digital oil immersion lithography system and a better than 200 nm resolution in the single line patterning. Also, with a double layered photoresist scheme and our lab-prepared photoresist, we successfully achieved large area lift-off patterns of 400 nm metallic dot arrays through the scanning digital oil immersion lithography system.

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Benefits and limitations of immersion lithography

Cited by 27 publications

References 15 publications

Immersion lithography and its impact on semiconductor manufacturing

Immersion lithography and its impact on semiconductor manufacturing

Fluid-photoresist interactions and imaging in high-index immersion lithography

Scanning digital oil immersion lithography providing high-speed large area patterning with diffraction limited sub-micron resolution

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