International adhesives manufacturer Delo has developed a flexible electronics adhesive that it says can permanently seal sensor housings airtight in order to protect components such as image sensors. Its DualBond BS3770 meets the stringent requirements of the semiconductor and automotive industries and can contribute to innovation in autonomous driving.
With ever-stricter safety requirements in the autonomous driving industry, reliable components such as image sensors are a key element of lidar and radar systems. Sensor housings on PCBs must be hermetically sealed throughout their entire service life in order to maintain their function permanently without interruption. However, Delo says that previous solutions for hermetically sealing the housing and filter glass are reaching their limits due to these stricter requirements, potentially failing to withstand the tests of the automotive industry and standard AEC-Q100.
Unlike those previously available on the market, Delo’s new adhesive is a flexible product with a Young’s modulus of less than 5MPa at room temperature, the company says. Due to its flexible properties, starting from a temperature as low as approximately -50°C, the adhesive can compensate for pressure changes that occur, such as those caused by temperature changes, humidity differences, or heat input in the reflow process during production. As a result, defects such as pop-ups or delamination do not occur, and the sensor is permanently protected.
The adhesive can be precisely applied by needle dispensing while maintaining narrow and high bondlines. Curing takes place in two consecutive steps using UV light and heat. After dispensing, the adhesive is fixed in a few seconds by means of classic light fixation. Alternatively, it can be transferred to the B-stage, which is particularly relevant for bonding filter glasses with blackprint. At this stage, it achieves an initial adhesion comparable to tape. Afterwards, the second component can be joined. Thanks to the adhesive’s initial adhesion, the component is directly fixed so that it can be entirely processed further. Final curing takes place in a convection oven at +150°C within 40 minutes.
In addition to image sensors for lidar and radar applications, Delo’s new DualBond BS3770 can also be used in driver monitoring and for 5G applications, the company states.