High performance RF inductors integrated in advanced Fan-Out wafer level packaging technology

This paper aims to make a full evaluation of inductor performances integrated in multi layer FO-WLP technology. Technology interest for radio frequency passives is first discussed. The inductor offer, composed of four different inductor families, is described including more than 200 different inductors that were fabricated. Measurements exhibit promising quality factors for such packaging technology, with Q>;50 for a 1.1nH inductor. Comparison with inductors integrated in CMOS demonstrates a 2.4 times quality factor improvement in favor of FO-WLP while the global size is nearly identical. FO-WLP technology has then to be considered as a very promising technology for the integration of high quality passive in CMOS.