A substrate for a fluid ejection device includes a first side, a second side opposite the first side, spaced etch stops extending into the substrate from the first side, and a fluidic channel communicating with the first side and the second side, wherein a first portion of the fluidic channel extends from the first side toward the second side between the spaced etch stops and a second portion of the fluidic channel extends from the second side toward the first side to the spaced etch stops.