Phase defect printability and mask inspection capability of 65-nm technology node Alt-PSM for ArF lithography (Photomask Japan Best Paper)

Akima, Shinji; Komizo, Toru; Kawakita, Saburo; Kodera, Yutaka; Narita, Tsuyoshi; Ishikawa, Kiichi

doi:10.1117/12.580003

Cited by 2 publications

(1 citation statement)

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“…[1][2][3][4][5] Usually, for any new technology node and material type extensive printability studies are performed in collaboration between maskhouse and customer to find an appropriate AIMS TM defect dispositioning criterion telling whether a defective site will later-on print on the wafer and therefore needs to be repaired or not. [6][7][8][9][10] Currently, a lot of effort is put on the simulation of defect printing to reduce the time consumption of printing studies and also to disposition defects in production. [11][12][13][14] However, the matching between AIMS TM results and simulations is often unsatisfactory since the imperfections of the AIMS TM optics are normally not included in simulations (e.g., flare, aberrations, cross-talk, inhomogeneous illumination).…”

Section: Introductionmentioning

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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