1, ceramic substrate
The substrate of the FC-CBGA is a multilayer ceramic substrate, which is quite difficult to manufacture in a pcb assembly factory. The substrate has a high wiring density, a narrow pitch, a large number of through holes, and a high coplanarity requirement of the substrate. Its main process is: firstly, the multilayer ceramic sheet is co-fired into a multilayer ceramic metallized substrate, and then a plurality of metal wirings are formed on the substrate, and then electroplating is performed. In the assembly of CBGA, the CTE mismatch between the substrate and the chip and PCB is the main factor causing the failure of the CBGA product. To improve this situation, in addition to the CCGA structure, another ceramic substrate, the HITCE ceramic substrate, can be used.
2, packaging process
Preparation of wafer bumps -> wafer cutting -> chip flip and reflow -> underfill thermal grease, sealing solder distribution -> capping -> assembly solder ball -> reflow soldering -> marking -> separation -> Final inspection -> Test -> Packaging.