150-nm dense/isolated contact hole study with Canon IDEAL technique

Ebihara, Takeaki; Rhyins, Peter D.; Oga, Toshihiro; Martin, Patrick; Sweis, Monika

doi:10.1117/12.458270

Cited by 3 publications

(1 citation statement)

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“…Registration performance among two masks 24nm 3σ in reticle scale or 6nm 3σ in wafer scale has been achieved. 4 Since this number is large and occupies most part of the alignment budget if 70nm L/S patterning is considered, the mask writer needs to improve the registration accuracy to utilize this double-exposure pitch-splitting scheme. On the other hand, the use of two masks allows full correction of process biases that may shift the CDs produced by the first and second exposure.…”

Section: Alignment Accuracymentioning

confidence: 99%

Beyond k1=0.25 lithography: 70-nm L/S patterning using KrF scanners

Ebihara

Levenson²,

Liu

et al. 2003

SPIE Proceedings

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The extendibility of optical lithography using KrF and ArF exposure tools is still being investigated, even, being demanded strongly now, due to the unforeseen issues, high cost, and general difficulty of NGLs -including F 2 and immersion lithography. In spite of these challenges Moore's Law requires continued shrinks and the ITRS roadmap still keeps its aggressive timetable. In order to follow the ITRS roadmap, the resolution must keep improving by increasing the lens NA for optical exposure tools. However, the conventional limit of optical resolution (k pitch =0.5) is very close for the current technologies, perhaps limiting progress unless NGL becomes available quickly. Therefore we need to find a way to overcome this seemingly fundamental limit of optical resolution. In this paper, we propose two practical two-mask /double-exposure schemes for doubling resolution in future lithography. One method uses a Si-containing bi-layer resist, and the other method uses Applied Materials' APF TM (a removable hard mask). The basic ideas of both methods are similar: The first exposure forms 1:3 ratio L/S patterns in one resist/hard mask layer, then the second exposure images another 1:3 ratio L/S pattern in-between the two lines (or two spaces) formed by the first exposure. The combination of these two exposures can form, in theory, k pitch =0.25 patterns. In this paper, we will demonstrate 70nm L/S pattern (140nm pitch) or smaller by using a NA0.68 KrF Scanner and a strong-RET reticle, which corresponds to k pitch = 0.38 (k 1 =0.19). We will also investigate the critical alignment and CD control issues for these two-mask / dual-exposure schemes.

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Section: Alignment Accuracymentioning

confidence: 99%