System-in-Package Wireless Solution for Wearable Alert Button

Driven by the increasing demand for smaller, lighter and more efficient devices, the electronic evolution is moving towards new approaches that enable the achievement of this goal. The solution is to increase the integration level of electronic components. Two of these levels are the integration in package (System-in-Package, SiP) and the integration in board (Printed Circuit Board, PCB). The former provides a method to integrate multiple bare die devices or passive components within the same package, while the latter enables the integration into a board in which packaged devices, including SiPs, are interconnected through conductive traces. The use of SiP and PCB with reduced dimensions allows to move towards miniaturized applications employed in various fields, including smartphones, automotive applications, aerospace, medical systems, and wearable devices. The objective of this thesis work is to realize a wearable safety device in the form of a button made of two parts: one attached to the user’s clothes and the other removable. The separation of the two parts enables the immediate transmission of a notification to a mobile device via Bluetooth. The button houses a System-on-Chip (SoC) capable of detecting the opening of the circuit. It is packaged using Wafer-Level Chip-Scale Package (WLCSP), thus achieving dimensions of only 3 x 3.2 mm that are comparable to those of bare die devices. This solution is a further step towards the SiP technology and the integration of chip-scale components. To enable the operation of the device, the SoC is powered by a battery and connected to various electronic components. These were carefully selected and subsequently assembled onto a small-sized PCB (25 x 25 mm) whose layout was performed by using a CAD in order to arrange the chosen components and draw the electrical connections among them. In addition, the design of a container for the PCB was performed to address the button mechanical opening. The design was carried out to facilitate the removal of the upper part of the device from the bottom, allowing a quicker response from a person in case of danger.