- The Embedded WLBGA is a sort of packaging technology for IC’s.
- Package interconnects are placed on wafers made of silicon chips and a special casting compound.
- This technology allows the creation of chips with a huge number of interconnects(ball grid array).
- Eac and single process for the interconnects(generation of package) is performed on the wafer.
- Hence a front end processed wafer is sliced and the singulated chips are placed on a carrier.The consecutive distance between each individual chip can be freely selected but usually it is larger than that of the silicon wafer.
- Now for the next step the extra edges and spaces around the central chip is filled with a compound (casting) in order to form a wafer.
- Next step involves the curing of the artificial mould frame. This in turn creates the dies for carrying extra package interconnects.
- Finally after this reconstructed artificial wafer layer is created the connections between chip pads and corresponding interconnects are made using thin film technology.
- The main advantage of this design is that multiple interconnects can be created on the package within an arbitrary(fan out) distance.
- This sensitive design can be employed in space applications where insufficient chip space is available for the interconnects to be realized.
Eg:- STATS, ChipPac,Infineon
Fig 2. Fan in design of chip interconnects
STEPS INVOLVED IN THE PROCESS:
- Mold press
- Chip placement onto the wafer.
- The Lamination of foil onto the carrier.
- The Debonding of carrier
- Turn the reconstructed wafers upside down.
- The ball drop reflow and wafers test.
- Compact and long.
- Good thermal and electrical properties.
- Good package standards.
- No interconnects restrictions on package.
- Very high integration potential for stacked and multi-die packages.
- High maintenance cost and visual restricted.
- High mechanical stress transmitted between the package and board as compared to other technologies.