The latest portable electronic devices are expected to go everywhere with us and withstand anything as soon as they leave the assembly line, but what about while they are still on the assembly line? In examining this challenging environment, W. L. Gore & Associates (Gore) developed GORE MEMS Protective Vents, designed to shield the device from extreme conditions faced during manufacturing and maximise yields.
During high volume assembly of printed circuit boards for mobile phones, cameras and other devices, there are several technical issues that can jeopardise the integrity of MEMS microphones.
These issues - including pressure build-up caused by the extreme heat during the solder reflow process, particle contaminants, and aerosolized solder droplets - have the potential to damage MEMS microphones, leading to acoustic performance degradation, significant yield losses, and higher manufacturing costs.
“Many manufacturers currently use non-porous tape to cover the microphone port during this process in order to prevent contaminants from entering,” said Mike Jacobs, Global Product Manager for GORE MEMS Protective Vents. “While this method is quite effective in preventing contamination, it unfortunately leaves the microphone prone to potentially damaging pressure build-up and prevents in-process acoustic testing.”
Partners in development
Gore’s Design and Engineering team have developed a solution - new GORE MEMS Protective Vents - 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.
Working directly with OEMs, Microphone Manufacturers and Contract Manufacturers, Gore has manufactured over 100 million GORE MEMS Protective Vents designed to handle the extreme stresses of high volume, high speed installation, as well as multiple reflow cycles of up to 280ºC (390°F) for 40 seconds.
“The conditions a MEMS microphone is put through during high-volume assembly can often be more extreme than those in the outside world,” said Jacobs, “and even the smallest particle or pressure differential can cause irreparable damage to the MEMS microphone or significantly degrade acoustic performance.”
MEMS protection inside or out
GORE MEMS Protective Vents are unique in their ability to provide reliable particle protection, while the breathable ePTFE membrane allows gases to pass through the microphone port to mitigate pressure build-up that may cause damage to the microphone.
These are available in two formats designed to meet the specific needs of both circuit board assembly and 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, right 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.