Standardized photon building blocks are used to make both discrete light emitters as well as array products. Each photon building block has one or more LED chips mounted on a substrate. No electrical conductors pass between the top and bottom surfaces of the substrate. The photon building blocks are supported by an interconnect structure that is attached to a heat sink. Landing pads on the top surface of the substrate of each photon building block are attached to contact pads disposed on the underside of a lip of the interconnect structure. In a solder reflow process, the photon building blocks self-align within the interconnect structure. Conductors on the interconnect structure are electrically coupled to the LED dice in the photon building blocks through the contact pads and landing pads. The bottom surface of the interconnect structure is coplanar with the bottom surfaces of the substrates of the photon building blocks.