An optical proximity sensor module includes a substrate, a light emitter mounted on a first surface of the substrate, the light emitter being operable to emit light at a first wavelength, and a light detector mounted on the first surface of the substrate, the light detector being operable to detect light at the first wavelength. The module includes an optics member disposed substantially parallel to the substrate, and a separation member, wherein the separation member is disposed between the substrate and the optics member. Multiple modules can be fabricated in a wafer-level process and can be composed of reflowable materials so that the modules can be incorporated more easily into devices whose manufacture occurs, at least in part, at elevated temperatures when the module is integrated into the device or during subsequent manufacturing processes.