Amkor Technology stacks die 3-high in IC packages; saves money for system designers and manufacturers

Citation

(2001), "Amkor Technology stacks die 3-high in IC packages; saves money for system designers and manufacturers", Microelectronics International, Vol. 18 No. 2. https://doi.org/10.1108/mi.2001.21818bad.011

Amkor Technology stacks die 3-high in IC packages; saves money for system designers and manufacturers

Amkor Technology stacks die 3-high in IC packages; saves money for system designers and manufacturers

Keywords Amkor, IC packages

Amkor Technology is expanding its development and qualification of 3D (stacked) IC packages, including the integration of three or more die and supporting passive devices.

The resulting packages cost less to produce, require less handling throughout the manu-facturing and mounting process, require less space, have higher reliability and better electrical performance than the combination of devices they replace.

Amkor has developed 3D packaging options that include die stacked three- or more high, stacked die of the same or different sizes and side-by-side 3D die stacks. 3D assembly techniques allow mixing of interconnect technologies within the package. These include die-to-die or die-to-substrate using combinations that can include either wirebond or flip chip technologies within the same package.

3D packaging was first introduced so mobile phones and other hand-held devices could be made smaller by allowing flash and static RAM chips to be vertically stacked within a single package. 3D packaging is emerging as a valuable enabler in OEMs' system-in-package (SIP) designs. Stacked die packages decrease the total system cost by reducing the number of components needed as well as simplifying the application's motherboard.

Additionally, stacked die reduce the length of interconnects between the devices, enhancing the electrical performance as well as final system application performance.

Amkor has been shipping 3D IC packages since 1999 for use in mobile phones and other emerging applications, including Internet routers and switches, base stations, PDAs and PCs. New applications, from chip sets to large memory blocks, are being investigated for potential development.

Current annual stacked package volumes will approach 230 million units this year, according to industry analyst TechSearch International, Inc. The firm estimates a 50 percent market growth to 348 million stacked packages by the end of 2002 for all applications.

Stacked packaging saves money for chipmakers and OEMs

For semiconductor makers and systems manufacturers, the cost savings of stacked IC packaging accrue in a number of ways:

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  Materials. Chipmakers achieve a lower component cost. While each individually packaged IC requires its own high-density interconnect substrate (the highest-cost material in the package), a 3D package requires only a single substrate/interposer. The cost of three-die stacked packages could be as much as 35 percent less than the cost of separate single die package options.

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  Test. The stacked package, or system-in-package, is tested as a single unit, eliminating tests for three or more individual die packages, reducing the handling compared to individual packages. Subsequent testing during board assembly also is reduced because device handling generally consumes more time than an actual test. The use of known-good-die at the wafer level increases the yield of stacked packages and is an area seeing continued development to further extend the cost savings of stacked and multi-chip packaging.

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  System. For the OEM, in addition to the 30 to 60 percent reduction in system-board area, 3D IC packaging reduces system-board wiring density and complexity by moving this interconnection challenge to inside the 3D package. Die-to-die wiring within the 3D package also reduces the external I/O count, allowing larger package mounting-pad pitches to be used, further reducing assembly costs and enhancing second level solder joint reliability. Because there are fewer components to handle, system assembly costs are also further curtailed. Additional indirect savings are realized because fewer components must be procured, qualified and inventoried. These advantages are gained with a minimal increase in mounting height for 3D packages, which utilizes wafer thinning and thin substrates to achieve 1.4mm for three die stacks and 1.2mm for two die stacks. Weight of stacked packages can be up to 70 percent less than multiple single-die packages capable of performing the same functions, an important consideration to a company supplying to consumer markets.

Further details: Tel: +1 480 821 2408, ext. 5130; E-mail: kjens@amkor.com; Internet: www.amkor.com