The polymer commonly used for hybrid copper bonding is called a "polyimide." Polyimides are a type of high-performance polymer known for their excellent thermal stability, electrical insulation properties, and mechanical strength. They are often used as dielectric materials in electronic packaging and semiconductor devices.
In the context of hybrid copper bonding, polyimide is utilized as an adhesive or bonding material between copper surfaces. Hybrid copper bonding refers to a bonding technique where copper structures, such as copper pillars or bumps, are bonded to other surfaces, such as a substrate or another chip. The polyimide acts as an intermediate layer that provides electrical insulation and mechanical support while facilitating the bonding process.
Polyimides have several advantageous properties for hybrid copper bonding, including high temperature resistance, low thermal expansion, and good adhesion to copper. These characteristics make polyimide an ideal choice for applications where high-temperature processing steps, such as flip-chip bonding or advanced packaging technologies, are involved.
It's worth noting that there are various types of polyimides available, and the specific formulation and properties of the polyimide used for hybrid copper bonding can vary depending on the application requirements and process conditions.