Additively manufactured gas distribution manifold

An apparatus for use with a semiconductor processing chamber, the apparatus comprising:

• a manifold constructed by additive manufacturing and including:
• a mixing chamber, and
• portions of a plurality of flow paths, each flow path including:
• a first fluid flow component interface including a first fluid flow component interface inlet and a first fluid flow component interface outlet,
• a first tubular passage fluidically connecting the first mixing chamber with the first fluid flow component interface outlet of that flow path, and
• a second tubular passage fluidically connected to the first fluid flow component interface inlet of that flow path, wherein:
• the first fluid flow component interface, the first tubular passage, and the second tubular passage of each flow path are a unitary body,
• one or more of the first tubular passage and the second tubular passage for at least one of the flow paths follows a respective pathway and has an exterior surface that includes a first runway,
• the pathway is a three-dimensional path, and
• for each runway:
• that first runway includes a surface defined by a respective first profile that is swept along the respective pathway,
• the respective first profile is in a plane perpendicular to the respective pathway, and
• the respective first profile is substantially linear.