Vents protect MEMS microphones in harsh environments
Designing portable electronic devices that can go anywhere has been given a new twist by WL Gore, which has focused on products that face extreme conditions during manufacture. It has developed Gore MEMS protective vents to shield microphones.
During high-volume assembly of PCBs for mobile phones, cameras and other devices, there are several technical issues that can jeopardise the integrity of MEMS microphones, such as pressure build-up caused by the extreme heat during the solder reflow process, particle contaminants and aerosolised solder droplets. All can potentially damage MEMS microphones, leading to acoustic performance degradation, significant yield losses and higher manufacturing costs.
Many manufacturers use non-porous tape to cover the microphone port during this process to prevent contaminants from entering. This prevents contamination but leaves the microphone prone to pressure build-up and prevents acoustic testing.
MEMS protective vents have been stringently tested and proven to prevent particle contamination and pressure build-up, allow in-process acoustic testing and integrate seamlessly into automated dispensing and placement processes.
The vents are designed to handle the extreme stresses of high-volume, high-speed installation, as well as multiple reflow cycles of up to 280 degrees C for 40 seconds.
They provide reliable particle protection while its breathable ePTFE membrane allows gases to pass through the microphone port to mitigate pressure build-up that may cause damage to the microphone.
Two formats are available, one for circuit board and one for microphone manufacturers. For circuit board assembly, Style 100 allows for installation, either over the top of a top-port microphone or on the circuit board opposite a bottom-port microphone, immediately before the reflow process. It is available in reel packaging to enable seamless installation with high-speed SMT pick and place machines.
For microphone manufacturers, Style 200 can be installed inside the MEMS microphone during the packaging process, providing particle protection without any special handling during the circuit board assembly process. Parts are digitally mapped in a wafer format and are compatible with high-speed die attach equipment.
