Patent ID: 7184909
Filing Date: 2007-02-27
Classification: H01L

Abstract:
1. A method for mounting semiconductor chips on substrates using a bondhead having a chip gripper, whereby the chip gripper has a shaft with a longitudinal drill hole to which vacuum can be applied and a suction organ with a suction opening and whereby the chip gripper can be rotated on a rotational axis, the method comprising calibrating a gripper axis running through the suction opening of the suction organ, the calibrating comprising: illuminating the longitudinal drill hole of the shaft of the chip gripper so that a light beam emerges from the suction opening of the suction organ, and determining co-ordinates (x moving the bondhead along a first travel path over a first edge of a light-sensitive area of a stationary arranged photodetector and determining a first co-ordinate x and moving the bondhead along a third travel path over a third edge of the light-sensitive area of the photodetector and determining a first co-ordinate y and determining a centre (x the method further comprising mounting one semiconductor chip after the other on a substrate by moving the bondhead to a first position for picking the semiconductor chip from a wafer table wherein the gripper axis points towards a desired pick point and moving the bondhead to a second position for placing the semiconductor chip on the substrate wherein the gripper axis points towards a desired place point, the first position and the second position depending in part on the vector.