Patent ID: 7597234

Claim:
A method for mounting a semiconductor chip having a surface with bumps onto a substrate location of a substrate wherein the bumps are brought into contact with corresponding pads on the substrate location and the positioning of the semiconductor chip over the substrate location is accomplished by means of a drive system including at least three axes of motion, the method comprising: a) picking the semiconductor chip from a wafer table; b) turning the semiconductor chip by 180° about an axis parallel to the surface with the bumps; c) passing the semiconductor chip over to a bondhead; d) presenting the substrate location; e1) making a first image of the semiconductor chip with a first camera having a first optical axis when the at least three axes of motion of the drive system are in a first position, wherein the first image shows the bumps of the semiconductor chip as well as reference marks attached to the bondhead, e2) determining from the first image the position and orientation of the actual position of the semiconductor chip in relation to a system of coordinates defined by the reference marks attached to the bondhead and, based thereon, e3) calculating a first correction vector v 1 that describes the deviation of the actual position of the semiconductor chip from its set position; f1) making a second image with a second camera having a second optical axis not aligned with the first optical axis wherein the substrate location in its actual position is visible in the second image and wherein the reference marks attached to the bondhead are not visible, f2) determining the position and orientation of the substrate location in relation to the system of coordinates defined by the reference marks attached to the bondhead, wherein fictitious positions are used for the positions of the reference marks that they would take up if the three axes of motion had been moved from the first position by a vector v to a second position, and, based thereon, f3) calculating a second correction vector v 2 that describes the deviation of the actual position of the substrate location from its set position; g) calculating the final position to be approached by the at least three axes of motion of the drive system based upon the vector v and the two correction vectors v 1 and v 2 ; h) moving the at least three axes of motion of the drive system to the calculated final position; and i) depositing the semiconductor chip onto the substrate location.