In a method of manufacturing a compound semiconductor device, individual chip patterns are projected onto a (1 0 0) surface of a GaAs wafer so that the columns and rows of the chip patterns are aligned in a direction slanting by 45 degrees with respect to a null0 1 1null direction of the GaAs wafer. The wafer is diced along this slanting direction and chipping along the edges of the individual separated chips is greatly reduced.