General process of making SIP

The process flow of FilpChip-BGA includes: wafer thinning → wafer bump generation → wafer cutting → chip flip → reflow soldering → bare chip bottom filling → surface marking →BGA substrate ball mounting → substrate reflow soldering → cutting separation → final inspection → test packaging.

Before FilpChip-BGA packaging, the wafer will be thinned and then bumps will be made on the wafer. After that, the wafer is cut, and then the chip is flip-chip bonded to the substrate. After welding, clean the bottom of the chip and glue it to fix the chip to overcome the stress caused by the inconsistency between the chip and the substrate CET. The process of ball planting, reflow soldering, cleaning, marking, cutting, testing and packaging of BGA substrate is basically the same as that of wire bonding -BGA.

By comparing the two processes, it can be seen that the basic processes of the two processes are the same, and the main difference is that flip-chip flip-chip bonding needs to generate bumps of the chip before cutting the wafer, and then carry out a series of processes such as flip-chip flip-chip and reflow soldering.

The whole process of flip chip needs two reflow soldering, including chip reflow soldering and BGA substrate reflow soldering. Wire bonding requires chip bonding, bonding, die sealing and other processes, and the whole process only needs one reflow soldering.

For SiP system-level package, because there are multiple chips, it is possible to encounter mixed technologies, that is, there are both WB chips and FC chips in a SiP package. At present, this situation is quite common in practical application and is often encountered in design. If there are chips supporting WB process and chips supporting FC process in the selected bare chips, it is necessary to manufacture mixed process SiP.