Low dielectric loss AlN ceramics fabricated via DLP 3D printing achieving high strength and thermal conductivity through plasticizer and optimized debinding

The influence of plasticizer PEG300 on the rheological and curing properties of AlN suspensions was firstly investigated. • The synergistic effect between plasticizer PEG300 and dispersant BYK110 was investigated. • The impact of debinding schedules on the properties of DLP-printed AlN ceramics was clarified. • The quality factor ( Q×f) was firstly introduced as a key evaluation metric for AlN ceramics in ceramic substrate. In this study, Digital Light Processing (DLP) was used to fabricate aluminum nitride (AlN) ceramics for electronic ceramic substrate. To address the two extreme issues of poor rheology and poor photocuring ability of slurry, the high-performance 50 vol% AlN suspensions were prepared through the combined use of the dispersant polyphosphoester and plasticizer PEG300. Meanwhile, to overcome the challenge of removing the excess organic matter from the 3D-printed green bodies, the optimal debinding and sintering schedule was established: debinding in a vacuum environment firstly, next decarburization is performed in air atmosphere, followed by final sintering in N 2 sintering furnace. Under this schedule, the AlN ceramics achieve the relative density of 99.3%, flexural strength of 344 ± 5 MPa, thermal conductivity of 172.5 W/(m·K). Furthermore, dielectric properties were evaluated in this work: the AlN ceramics exhibited optimal dielectric performance of ε r = 8.36, tan δ = 1.22 × 10 −3 at 14.3 GHz ( Q×f = 11754.6 GHz).