Abstract: A hermetically sealed thermal shock resistant ultraviolet light responsive read only semiconductor chip package includes a pair of mating ceramic members one of which mounts an ultraviolet sensitive semiconductor chip and the other which provides a window having an ultraviolet light transmitting glass sealingly mounted therein. The ultraviolet responsive chip is hermetically packaged by selecting a ceramic base member and a mating ceramic cap member, mounting an ultraviolet sensitive chip on the base and forming an ultraviolet transmitting window in the cap member and thereafter mating and sealing the members together so that the window covers the chip for permitting the transmission of ultraviolet rays thereto.