Patent ID: 7284318

Claim:
Apparatus for mounting semiconductor chips, with a pick and place system for pick-up, transport and placement of a semiconductor chip onto a substrate, the pick and place system comprising a bondhead, the bondhead including: a chip gripper, the chip gripper being deflectable in relation to the bondhead, a pneumatic drive for controlling a deflection of the chip gripper, the pneumatic drive being formed from two pressure chambers separated by a piston, a position encoder for measuring the deflection of the chip gripper, the apparatus further comprising: a valve system for controlling a pressure p 1 prevailing in the first pressure chamber and a pressure p 2 prevailing in the second pressure chamber, a first pressure sensor for measuring the pressure p 1 prevailing in the first pressure chamber, a second pressure sensor for measuring the pressure p 2 prevailing in the second pressure chamber, and a regulator operable in two operating modes for controlling the valve system, the first operating mode controlling the deflection of the chip gripper or a variable derived from the deflection and the second operating mode controlling the first pressure p 1 and the second pressure p 2 or the second operating mode controlling the pressure differential p 1 -p 2 .