In terms of the measurement of wafers and flat panels, it is tremendously important to lead the sensor chip precisely and without any contact along the surface. Therefore the chip is integrated directly into the bearing’s surface. The maximum distance tolerance to the surface which refers to the gap variation of the air bearing, is smaller than 0.5 µm. When placing the air bearing with the sensor chip, they must not touch the wafer surface being measured. As for the up-and-down movement a pneumatic piston is used which is, for repeatability reasons, also air-guided. The preload of the air bearing and thus the gap height is also adjusted with this piston.

The drive unit for packaging of non-casing chips (bare dies) into plastic tapes for SMT technology (PCB assembly) consists of a needle drive (ejector) and a pick-up drive (pipette). Both drives are air-guided and based on voice coil motors. The pick-up module drives both the vacuum pipette and the centering spigot for the tape. The packaging module proves to allow a 4 to 5 times higher productivity than all alternative modules on the market! When adapting, the module can be applied for die and wire bonding as well.

For the electrical testing of wafers the chuck can be lifted stick-slip-free up to 3 mm. The needed contact force for the probe is adjustable and independent from stroke. The lift drive bases on a voice coil motor; the guidance is air-guided. An air-guided pneumatic piston between the chuck and the drive is limiting the contact force.

Reliability, dynamic, repeatability, and oil/fat freedom, these are the advantages our customers appreciate of our drive systems. Since 2000 our series solutions for the Back End are applied world-wide.

Directly air-guided on the ground plate, the axis of rotation is not serial-mounted on a linear axis. Thus a high flatness and runout of the rotary disk (chuck) is made possible. The bearing is statically determined guided and thereby insensitive to deformations of the system and to temperature influence.