Copper-clad ceramic substrates usually use materials such as alumina (Al₂O₃), aluminum nitride (AlN), zirconia-toughened alumina (ZTA), and silicon nitride (Si₃N₄).
Performance and Key Features
According to data from Fulade, DBC-ZTA substrates offer higher reliability compared with DBC-Al₂O₃. They also provide a more cost-effective alternative to AMB copper-clad substrates. With the rapid growth of China’s electric vehicle market, DCB ceramic substrates based on ZTA are gaining attention. These substrates meet the performance requirements of entry-level EVs and are commonly used in core components like battery modules and inverters. As a result, market demand for ZTA substrates continues to rise.
ZTA Ceramic Substrates Overview
1) Structure and Mechanism
ZTA ceramics are composite materials, with Al₂O₃ as the base and partially stabilized ZrO₂ as the toughening phase. This combination results in mechanical properties that fall between pure alumina and zirconia. ZTA retains the hardness and wear resistance of alumina while offering the fracture toughness and bending strength of zirconia—all at a lower cost than pure ZrO₂.
2) Mechanical Performance
The thermal expansion of ZrO₂ is higher than that of Al₂O₃, and its sintering temperature is lower. After sintering, ZrO₂ grains are under tensile stress, which facilitates a phase transformation from tetragonal to monoclinic. This transformation generates compressive stress in the matrix, slowing crack propagation and enhancing toughness.
Advantages of ZTA Substrates
Enhanced Toughness
ZTA combines zirconia’s toughness with alumina’s hardness, making it more resistant to cracking and impact than pure alumina—particularly useful for mechanically demanding applications.
Better Thermal Shock Resistance
ZTA withstands rapid temperature changes without cracking, ideal for applications with fluctuating temperatures.
Improved Crack Control
Zirconia inhibits crack propagation, which is valuable for substrates subject to repeated or cyclic loads.
Reduced Brittleness
ZTA is less brittle than alumina, making it more adaptable in stress-prone environments.
Higher Bending Strength
ZTA generally offers superior bending strength, suitable for components under high mechanical loads.
Lightweight Potential
Stronger and tougher than alumina, ZTA allows thinner, lighter components without sacrificing performance.
Customizable Properties
ZTA's composition can be adjusted to meet specific performance requirements, allowing flexible design for different applications.
Good Wear Resistance
Hardness and toughness give ZTA excellent resistance to wear and abrasion.
Applications
Due to its excellent thermal conductivity, insulation, thermal shock resistance, and mechanical strength, ZTA copper-clad ceramic substrates are widely used in pressure sensors, IGBT packaging, DC-AC inverters, and e-cigarette heaters. These substrates are especially suited for industries that require reliable heat dissipation, electrical insulation, and durability under demanding conditions.
