NOVELTY - The solid state radiation transducer assembly (210) has a substrate (212), a radiation transducer (220), a first contact (251), and a second contact (252). The substrate has an epitaxial growth material. The radiation transducer has a first semiconductor material (222) grown on the substrate, a second semiconductor material (226), and an active region (224) between the first and second semiconductor materials. The substrate has an opening (217) through which radiation can pass to and/or from the first semiconductor material.    USE - Solid state radiation transducer assembly, e.g., LED assembly, photovoltaic cell assembly, or wavelength converter.    ADVANTAGE - Reduces the costs of packaging and handling solid state radiation transducer assemblies by removing only a portion of the growth substrate to expose the radiation transducer such that the remaining portion of the growth substrate can support the radiation transducer through subsequent handling and processing. Eliminates the need for a separate carrier substrate and the processing necessary to attach the separate carrier substrate to the radiation transducer. Simplifies manufacture by forming a backside routing structure to commonly connect the contacts of multiple solid state radiation transducer assemblies in an array, allowing the routing to be formed at the wafer level using known techniques for forming redistribution layers on memory or processor dies.    DETAILED DESCRIPTION - The first contact is electrically coupled to the first semiconductor material. The second contact is electrically coupled to the second semiconductor material. An INDEPENDENT CLAIM is also included for a method of making a solid state radiation transducer.    DESCRIPTION OF DRAWING(S) - The drawing is a partially schematic cross-sectional illustration of a system having a packaged solid state radiation transducer assembly.    Solid state radiation transducer assembly (210)    Substrate (212)    Opening (217)    Radiation transducer (220)    First semiconductor material (222)    Active region (224)    Second semiconductor material (226)    First contact (251)    Second contact (252)