An object is to provide a semiconductor chip manufacturing method capable of removing test patterns in a higher efficiency in simple steps, while a general-purpose characteristic can be secured.In a method in which a semiconductor wafer 1 having integrated circuits 3 formed in a plurality of chip regions and test patterns 4 formed in scribe lines 2a is divided by a plasma etching process so as to manufacture individual semiconductor chips, laser light 5a is irradiated from the side of a circuit forming plane 1a so as to remove the test patterns 4; and thereafter, under such a condition that a circuit protection seat 6 is adhered onto a circuit forming plane 1a, a rear plane of the circuit forming plane 1a is mechanically thinned; a mask-purpose seat is adhered onto the rear plane 1b of the semiconductor wafer 1 after the plane thinning process; and then, a plasma dicing-purpose mask is work-processed by irradiating laser light. As a consequence, the semi-conductor wafer 1 can be held by employing one set of the circuit protection seat 6 from the thinning process up to the plasma dicing process.