Methods for reducing heat transfer in semiconductor devices, and associated systems and devices, are described herein. In some embodiments, a method of manufacturing a semiconductor device includes forming a channel in a region of a substrate between a first die stack and a second die stack. The first die stack includes a plurality of first dies attached to each other by first film layers and the second die stack includes a plurality of second dies attached to each other by second film layers. The channel extends entirely through a thickness of the substrate. The method also includes applying heat to the first die stack to cure the first film layers. The channel reduces heat transfer from the first die stack to the second die stack.