A chip-scale package for an edge-emitting semiconductor device and a semiconductor device assembly including such a chip-scale package are provided. The chip-scale package includes an edge-emitting semiconductor device chip, a top submount disposed on a top surface of the chip, and a bottom submount disposed on a bottom surface of the chip. The top-submount area and the bottom-submount area are each greater than the chip area and less than or equal to about 1.2 times the chip area.