| 摘要 |
An apparatus for mounting semiconductor chips has a pick and place system arranged stationary in vertical direction for the picking, transport and placement of a semiconductor chip onto a substrate. The pick and place system comprises a bondhead with a chip gripper deflectable relative to the bondhead. The deflection of the chip gripper takes place by means of a pneumatic drive arranged on the bondhead which has two pressure chambers separated by a piston, whereby the chip gripper is secured to the piston. The pressure p<SUB>1 </SUB>prevailing in the first pressure chamber and the pressure p<SUB>2 </SUB>prevailing in the second pressure chamber are dynamically controlled by means of a regulator controlled valve system. The regulator can be operated in two operating modes. In the first operating mode, the deflection of the chip gripper and/or a variable derived from it is controlled based on the signal delivered by a position encoder which measures the deflection of the chip gripper. In the second operating mode, the pressure p<SUB>1 </SUB>and/or the pressure p<SUB>2 </SUB>and/or the pressure differential p<SUB>1</SUB>-p<SUB>2 </SUB>is controlled.
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