Abstract: Herein disclosed are systems and methods related to semiconductor processing device including a manifold including a bore configured to deliver a gas to a reaction chamber, the manifold including a first block mounted to a second block, the first and second mounted blocks cooperating to at least partially define the bore. The manifold may further comprise an insulator cap disposed about the first block or the second block. The semiconductor processing device may comprise at least three valve blocks mounted to the second block so that a precursor backflow is prevented. Heater rod(s) can extend through the second block to a location adjacent the first block.