Wafer LevelPackaging (WLP) is an interconnect technology for chip-to-chip connections. It differs from conventional packaging of integrated circuits in that all processes
take place directly on the wafer and the WLP packages are only cut out of the wafer after packaging. With WLP packaging, the packaging already takes place on the wafer, which means that the size of the integrated components is smaller and their connections are shorter, which enables higher throughput rates. While in conventional packaging the wafers are further processed in other manufacturing facilities where they are tested, diced, assembled and encapsulated, in WLP packaging the electrical connections are already made on the wafer. In the case of 3D chips, the individual layers can be connected to each other by means of bonding or silicon vias
. Only then are the 3D ICs encapsulated. TheWLP process is comparable to the Chip Scale Package (CSP), since the resulting package is practically the same size as the dice. The form factor, which is calculated from the ratio of package size to chip size, is therefore 1. The WLP technique basically maps out the path for integrated manufacturing on the wafer: the test and burn-in, packaging and dicing
. Wafer level packaging has a much higher production level and is therefore cheaper than conventional chip scale packaging. Waferlevel packaging can be applied
. Wafer level packaging is used in wafer level BGA (WLB), wafer level chip scale package (WLSCP) and wafer level cameras (WLC), among others. A further development of the WLB package is the Embedded Wafer Level Ball Grid Array (eWLB), which is much thinner than the classic BGA package. It can be used wherever package thickness is an issue. For example, in flat mobile devices. eWLB packages have good thermal and electrical properties and can be produced more cheaply than other WLB packages.