Quality assurance

AN4428

10/18

DocID025706 Rev 1

Figure 5. 4 x 5 pick-and-place process

The nozzle for picking up a 4 x 5 microphone is commonly a steel picker with a cylinder

shape respecting the safe area indicated in Figure 4: Picking area for 4 x 5 microphones.

The vacuum port at the bottom side of the picker is a hole with a diameter of 1 mm.

The safe pickup area for the 3 x 4 microphone is almost the same but with different

dimensions due to the different package outline. As shown in the previous design, the

following area has been dimensioned, also considering the tolerances of all the mechanical

parameters involved in the process; i.e. position of the sound inlet, microphone package

dimensions and pocket dimensions. The 3 x 4 safe area is indicated in the following figure.

Figure 6. Picking area for 3 x 4 microphones

To optimize the microphone yield, a dedicated picker has been designed to fully fit the

allowable safe area; hence, the currently used nozzle for the 3 x 4 microphones has 4

vacuum holes for each corner (refer to Figure 7).

AM17605 1

Steel

nozzle

Device

Tape &

reel