Embedded Wafer Level Ball Grid Array

Embedded Wafer Level Ball Grid Array ( eWLB ) is a housing design for integrated circuits in which the package leads are generated on an artificially -made chips and wafer sealing compound.

Development

EWLB is a development of wafer level ball grid array technology (WLB, including: wafer level package, WLP), which is characterized in that all the necessary processing steps for the housing to be performed on the wafer. This allows over the classical housing technologies (such as Ball Grid Array) producing extremely small and flat housing with excellent electrical and thermal properties at very low cost.

In wlbs that are produced on the silicon wafer, all solder contacts on the chip must match (german fan-in design). Therefore, only blocks with a limited number of contacts can be housed. Related designs are wafer level package and ball grid array.

Production

In contrast, allows the eWLB technology chips with many contacts to produce. The housing is not made ​​as in conventional wafer level packages on the silicon wafer but also to an artificial wafer. To this end, a front-end fully processed wafer is sawn and implemented the individual chips on a carrier plate. The chips will be stored to each other at a greater distance than was the case in the silicon. The intermediate spaces, and the edge area will then be filled by a sealing compound. After the curing, an artificial wafer is developed, which includes a frame made of potting compound ( Moldrahmen ) to the chips can be placed on the additional soldering. After the production of the artificial wafer, known Reconstitution now as conventional wafer level packages, the electrical connections to the solder terminals ( tie layers, also called rewiring ) produced in thin film technology. It is possible to use this technology as many additional solder contacts accommodate the desired distance on the housing (german fan-out design). This allows the wafer - level packaging technology used for new, space- sensitive applications where the chip area is not sufficient for the accommodation of the contacts in a feasible distance. The eWLB technology was developed by Infineon. First building blocks are in mid-2009 on the market come (mobile phone).

Pros and Cons

The advantages of the low cost (housing and test ), the minimum enclosure dimensions in height and width, the excellent electrical and thermal property and the unlimited realizable number of terminals, and a high potential for integration of multi-chip and stacked blocks and an emerging housing standard come to fruition.

Another disadvantage is the difficult inspection and repair of the building blocks ( visual inspection only to a limited extent ) and the mechanical stresses between housing and PCB that are more transferred to the component than with other forms of housing.