KYOCERA announced its copper bonded silicon nitride ceramic substrate achieved 5000 cycles of air-to-air temperature cycling at -60°C to 175°C without any failure. Its base ceramic substrate is Kyocera silicon nitride (Si3N4) with 850 MPa of flexural strength and 5.0 MPam1/2 of fracture toughness. This silicon nitride is much stronger than other ceramics, such as alumina (Al2O3) with its 274 MPa of flexural strength and 3.3 MPam1/2 of fracture toughness. Another comparison may be made with aluminum nitride (AlN), which offers 400 MPa and 2.7 MPam1/2.
Copper is bonded on the silicon nitride substrate by an active metal bonding (AMB) method using silver-copper-titanium brazing metallization. Active metal bonding is a stronger method of adhering copper to ceramics when compared to conventional copper bonding methods without metallization, typically using a copper-oxide process. The AMB copper bonded silicon nitride substrate is much stronger mechanically than conventional copper bonded alumina and aluminum nitride substrates. Kyocera AMB silicon nitride technology is suitable as a substrate material for use in power microelectronics applications in automotive, aerospace and other harsh environments.
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