ASE: The challenge and importance of MEMS and sensor packaging
MEMS and sensor devices have catapulted the Internet of Things (IoT) toward the deployment of billions of sensors in a myriad of applications in electronics technology that will improve the world around us as well as enhance the human condition. In reality MEMS and sensors exist today with incredible capabilities which are continuously being enhanced with more integration. Their physical size is shrinking and the energy needed to power them is ever being lowered.
Smart module and SiP integration will allow the huge deployment of connected devices in the IoT. To enable this, the different solution providers within the value chain will need to work together. A simplified supply chain needs to emerge and system integrators need to develop things like design kits for industry design engineers to evaluate different system configurations before designing a specific module or SiP. ASE Group has a design kit (DK) that will help designers to get a faster time-to-market.
Image courtesy of ASE
Designers can go from prototype to production inside of four months with a development kit like this.
Image courtesy of ASE
An oft-forgotten component of MEMS and sensors is the physical package which mechanically protects the MEMS/sensor and the electrical interconnects, and provides thermal management. Christophe Zinck, senior applications engineering manager at ASE, says that there is much customization in these types of packages for different solutions and new process developments are emerging especially in MEMS; standardization across platforms is not possible. His company will perform an in-depth simulation of a package design and then give that to the customer to evaluate virtually before the package is actually fabricated. The package needs to be considered at the very beginning of a design.
Stress optimization is a critical aspect of the package design for a MEMS/sensor design. Simulations will demonstrate the maximum stresses on a package, look at warpage and see how the package performs when made up of different types of materials (Figure 1).
Applications such as consumer products and smartphones sometimes attach sensors to glass. Strong modeling is a must here as well as modeling design interactions that may sometimes leverage existing platforms. Zinck says that optical design for manufacturing (DFM) will have future applications like changing radio frequency with the motion of a hand. A good example of optimum package selection for a particular MEMS device such as an inertial measurement unit (IMU) is shown in Figure 2.
Figure 2 Package maximum stress and warpage over temperature are critical factors to a successful IMU solution. (Image courtesy of ASE)
Different packaging technologies and bill of materials (BOM) selection criteria will determine the level of performance that a customer needs (Figure 3).
Figure 3 Inertial and environmental sensors have different needs. The customer can choose the best parameters for their individual needs in a package solution. A package is more than just protection. (Image courtesy of ASE)