Stochastic effects in currently practiced EUV lithography should be widely acknowledged by now. Four months ago, Samsung published an open-access study of the impact of various stochastic factors in EUV lithography [1]. Basically, there were two categories: (1) optical stochastic effects, which should include shot noise from photon density and released electron density, as we...

On March 24, in a filing with DART, a repository of Korea’s corporate filings, a nearly 12 trillion won (~8 billion USD) order for EUV scanners was shown as being placed by SK hynix with ASML Korea as the counterparty (Figure 1) [1].

Thinner and thinner resists are expected to be used for printing smaller and smaller features with EUV. There are two reasons behind this. First, a move toward higher NA (from 0.33 to 0.55) significantly reduces EUV’s depth of focus [1]. Second, a smaller feature cannot support an aspect ratio greater than about 2 before there is a risk of collapse [2] or less effective etchi...

In this article, we will dive further into linking electron noise in EUV resists [1] to stochastic defectivity. In particular, it will be shown how the “floor” or the lower limit of a defect’s probability naturally comes about, when electron noise is combined with resist thinning with increasing dose [2]. We first review the probability for a 3 nm long, 4 nm wide defect (nega...