DocID025706 Rev 1

9/18

AN4428

Quality assurance

18

1.3

Pick-and-place settings

The process of assembly of the printed circuit boards is fully automated owing to dedicated

machines. Basically these machines are used for high-speed, high-precision placement of

electronic components, like capacitors, resistors, or integrated circuits onto the PCB. These

systems normally use pneumatic suction cups, and at the end, a nozzle accurately picks the

device from a predetermined area.

Figure 3. Pick-and-place machine

In the case of microphones, this process must be rigorously controlled since the position of

the nozzle, the force involved in the pick and place, and the mechanical parameters can

damage the structure of the microphone. Hence, a reference/safe pick area is defined for

each microphone depending on the dimension of the package.

The reference pickup area for the generic 4x5 top-port MEMS microphone is shown in

Figure 4.

Figure 4. Picking area for 4 x 5 microphones

Basically the safe area has been set in order to not pick up the component by the top of the

microphone sound port, thus preventing damage to the MEMS membrane or an incorrect

pickup and placement. Additionally this safe area has been dimensioned, 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.

Suction cup

Nozzle

Device

AM17604v1