Optical proximity strategies for desensitizing lens aberrations

Petersen, John S.

doi:10.1117/12.425214

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…3(a)] only the 0 th order falls in the NA and thus the pattern will not be resolved on the wafer or in the AIMS TM -tool. [17][18][19] Still using a point-source, however, from an off-axis position [see Fig. 3(b)] the refraction pattern is simply moved and two orders fall into the NA enabling pattern imaging.…”

Section: Imaging Of Patternsmentioning

confidence: 99%

The importance of being homogeneous: on the influence of illumination inhomogeneity on AIMS images

et al. 2005

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Defect disposition and qualification with stepper simulating AIMS TM tools on advanced masks of the 90 nm node and below is key to match the customer's expectations for "defect free" masks, i.e. masks containing only nonprinting design variations. For defect dispositioning usually printability studies are carried out using the same illumination settings at the AIMS TM tool as later on at the steppers in the wafer fab. These studies then establish an AIMS TM criterion (e.g., CD variation or transmission deviation) a structure deviation must not exceed. For ever more advanced technologies the accessible process window gets smaller and thus more and more complex apertures have to be used to allow for a still suitable contrast and reliable printing of the patterns. This results in more time-consuming printability studies and tighter AIMS TM specs. Simulations of the printing of mask defects could potentially help to decrease the amount of time for printability studies and also the time for defect disposition in the production. However, usually simulations in their first approximation do not account for effects such as flare, aberrations or illumination inhomogeneities of the AIMS TM tool. This makes it difficult to derive the AIMS TM criterion by simulations. In this paper we show that a homogeneous aperture illumination is crucial for the image contrast and the defect disposition. We present a method to characterize the pupil illumination and investigate the impact of illumination inhomogeneities on various structures and their orientation employing two different aperture types. The experimental results are compared to simulations with both homogeneous illumination and the real illumination distribution. It turns out that for correct simulation predictions on experimental results it is important to provide the correct illumination distribution to the simulations.

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Section: Imaging Of Patternsmentioning

confidence: 99%

The importance of being homogeneous: on the influence of illumination inhomogeneity on AIMS images

et al. 2005

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“…Our study focuses on the control of linear astigmatism aberration. Other techniques for aberration mitigation in projection lenses not discussed in this paper are using off-axis illumination and image processing [16].…”

Section: Introductionmentioning

confidence: 99%

Control of Linear Astigmatism Aberration in a Perturbed Axially Symmetric Optical System and Tolerancing

Sasián

2021

Applied Sciences

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“…For example, wavefront engineering now dominates (and often gates) the design of low-k1 lithographic circuits since OPC and PSM methodologies have clearly been shown to improve lithographic yields and circuit performance 7 . Additionally, since the projection optics for next generation scanners (including immersion) require lens aberrations on order of 5mλ rms 8 the ability to measure lens performance rapidly and accurately (sub-mλ) will most likely become routine by necessity 9 . In fact, lithographic tool vendors (NIKON, ASML, and CANON) are increasingly developing methods to both measure and correct lens aberrations using in-situ metrology or on-board sensor technology 10 .…”

Section: Introductionmentioning

confidence: 99%

A simulation performance framework using in situ metrology

Bendik¹,

Yamaguchi²,

Finkner

et al. 2005

Optical Microlithography XVIII

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Modern lithographic simulation engines 1 are quite capable of determining the detrimental impact of source and lens aberrations on low k1 lithographic metrics -given the proper input 2 . Circuit designers, lithographic engineers, and manufacturing facilities would seem to be the beneficiaries of the predictive power of lithographic simulators; however, in-situ methods for accurately determining lens aberrations and source metrology maps have only rather recently been accepted 3 and integrated into practice 4 . For this work, we introduce several new methods for characterizing scanner performance including a high accuracy source metrology tool and integrated simulation engine 5 . We focus attention on the combined detrimental effects of lens aberrations, source non-ideality, distortion, synchronization error, and transmission error on deep sub-wavelength lithographic metrics such as: H-V bias, feature-shift, and ∆CD. After a brief theoretical discussion, we describe a matrix of simulation case studies and present results. Finally, we discuss potential applications for the simulation performance framework and its potential impact to industry.

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Optical proximity strategies for desensitizing lens aberrations

Cited by 5 publications

References 13 publications

The importance of being homogeneous: on the influence of illumination inhomogeneity on AIMS images

The importance of being homogeneous: on the influence of illumination inhomogeneity on AIMS images

Control of Linear Astigmatism Aberration in a Perturbed Axially Symmetric Optical System and Tolerancing

A simulation performance framework using in situ metrology

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