Real Research Challenge Problem:

Below is an image from my research at NIST and I think you all are equipped to solve to identify the mechanism of deformation. This is a cross-sectional electron image of an extreme ultra-violet (EUV) mask (used for lithography or printing or nano-scale electronic circuits by Intel). The EUV mask is composed of a Ni capping layer followed by stacked layers of Molybdenum (Mo, dark layer) and Silicon (Si, light layer) as shown in (a), all on top of a Silicon substrate.

It was proposed to try to use the helium on beam to cut or "machine" the EUV mask, however other unexpected phenomena occurred. First, there is an observed shrinking of the EUV mask thickness (b, c), second, the layers become obscured in the top of the stack (c, d), and third there is an expansion and ultimately, the formation of bubbles (d).

(a) Pristine EUV mask with no ion beam exposure, (b)-(d) Increasing helium ion beam does from 1x10¹⁶ ions/cm² to 1x10¹⁸ ions/cm².