DEVELOPMENT OF AS-FIRED ALUMINUM NITRIDE SUBSTRATES WITH SMOOTH SURFACE AND HIGH THERMAL-CONDUCTIVITY

As-fired aluminium nitride (AIN) substrates with smooth and uniform surface have been developed by green sheet and firing technology. The effect of setting for firing on surface roughness was investigated. AIN substrates were fabricated by pressureless sintering of green sheets piled up and sandwiched between AIN plates in an AIN crucible. The thermal conductivity, surface roughness and bending strength of the substrate sintered at 1770-degrees-C for 2 h under a pressure of 1 MPa nitrogen were 194 W m-1 K-1, 0.15 mum and 353 MPa, respectively.