EUV lithography systems continue to be the source of much hope for continuing the pace of increasing device density on wafers per Moore’s Law. Recently, although EUV systems were originally supposed to help the industry avoid much multipatterning, it has not turned out to be the case [1,2]. The main surprise has been the
Tag: Fred Chen
Revisiting EUV Lithography: Post-Blur Stochastic Distributions
In previous articles, I had looked at EUV stochastic behavior [1-2], primarily in terms of the low photon density resulting in shot noise, described by the Poisson distribution . The role of blur to help combat the randomness of EUV photon absorption and secondary electron generation and migration was also recently considered… Read More
Calculating the Maximum Density and Equivalent 2D Design Rule of 3D NAND Flash
I recently posted an insightful article  published in 2013 on the cost of 3D NAND Flash by Dr. Andrew Walker, which has since received over 10,000 views on LinkedIn. The highlight was the plot of cost vs. the number of layers showing a minimum cost for some layer number, dependent on the etch sidewall angle. In this article, the same… Read More
CD-Pitch Combinations Disfavored by EUV Stochastics
Ongoing investigations of EUV stochastics [1-3] have allowed us to map combinations of critical dimension (CD) and pitch which are expected to pose a severe risk of stochastic defects impacting the use of EUV lithography. Figure 1 shows a typical set of contours of fixed PNOK (i.e., the probability of a feature being Not OK due… Read More
Fully Self-Aligned 6-Track and 7-Track Cell Process Integration
For the 10nm – 5nm nodes, the leading-edge foundries are designing cells which utilize 6 or 7 metal tracks, entailing a wide metal line for every 4 or 5 minimum width lines, respectively (Figure 1).
Figure 1. Left: a 7-track cell. Right: a 6-track cell.
This is a fundamental vulnerability for lithography, as defocus can change… Read More