A lid for a wafer-scale package includes a body having a bond area around a cavity defined by the body, an oxide layer atop the bond area and the cavity, and a reflective layer atop the oxide layer. The cavity has an angled sidewall where a portion of the reflective layer over the angled sidewall forms a mirror for reflecting a light. The lid further includes a solder layer atop another portion of the reflective layer over the bond area, and a barrier layer atop the mirror. The barrier layer is solder non-wettable so it prevents the solder layer from wicking into the cavity and interfering with the mirror. The barrier layer is also transparent to the light and has a thickness that either does not affect the light reflection or improves the light reflection.