PURPOSE: To cut a wafer without generating contaminating materials by forming grooves of the width smaller than a laser beam diameter on the wafer along desired lines to be cut, then irradiating these grooves with a laser beam, thereby dividing the wafer.
CONSTITUTION: The grooves 2 are formed along the desired lines to be cut of the wafer W. The grooving is executed by photolithography or chemical dry etching, etc., preferably to about 2 to 3μm groove width. Thermal stresses act on the irradiated position and a crack C is generated in the bottom of the groove 2 if the positions near the end edge of the wafer W is irradiated with the laser beam L. The crack C is guided and progressed along the groove 2 when the position irradiated with the laser beam L is moved along the groove 2. The dividing of one line is thus completed. The generation of the contaminating materials by evaporation and dissolution is obviated and the characteristics of devices of LSIs and ICs, etc., on the wafer are not adversely influenced.
TANAKA MINORU
TAGUCHI YOSHINAGA
MAEKAWA SHUNICHI
INAMINE HAJIME
KUNII YOJI
SOUEI TSUUSHIYOU KK