Development of AlN substrate for high frequency devices

Recent improved of larger-scaled microwave devices at the field such as communication systems demand a high-performance wiring substrate which has high thermal conductivity and good high-frequency characteristics. Aluminum nitride (AlN) has been considered a hopeful candidate to meet these demands because of its high thermal conductivity, but it also has been considered inferior to aluminum oxide because of its high dielectric loss. In this report, we have developed a new composition of AIN to meet the above demands and also cleared the detail of high-frequency characteristics of dielectric constant and dielectric loss. Furthermore we have cleared conductor loss of Tungsten (W), which is used as pattern materials of co-fired and multilayered substrate