Methods are provided for fabricating an interlayer structure useful in, for instance, providing BEOL interconnect for circuit structures. The method includes, for instance, providing an interlayer structure, including: providing an uncured insulating layer above a substrate structure; forming an energy removal film over the uncured insulated layer; forming at least one opening through the energy removal film and extending at least partially into the uncured insulating layer; and applying energy to cure the uncured insulating layer, establishing a cured insulating layer, and decomposing in part the energy removal film, establishing a reduced thickness, energy removal film over the cured insulating layer, the interlayer structure including the cured insulating layer, and the applying energy decreasing an aspect ratio(s) of the one opening(s). In one implementation, the uncured insulating layer includes porogens which also decompose partially during applying energy to further improve the aspect ratio(s).