Aimed at memory die for digital storage and I/O applications, leadframe-based memory cards cut packaging costs by as much as 50% over conventional laminate-based solutions. Proprietary processes developed at Amkor Inc. brought the cards to fruition.
"The process of using a leadframe structure is more challenging to solve than the more costly and common laminate process," explains Jeff Miks, Amkor's Memory Card product manager. "We're the first to solve it."
The processes can create both lidded and nonlidded memory cards in a fully molded configuration for MultiMedia Card and SecureDigital Card (MMC/SDC) formats. Lidded leadframe cards use an established automated process, which deposits adhesive material on the card housing (lid) and then attaches it to the die assembly with placement accuracy of 0.5 mil. Fully molded leadframe cards use the MMC/SDC-compliant form, without a separate lid assembly. In either case, the leadframe of the die assembly has the seven/nine-pin connector that corresponds with the connector in the end-use application. Over-molded die assembly for either the lidded or fully molded MMC/SDC typically include memory, passives, and a microcontroller.
MMCs are assembled to a standard 24- by 32- by 1.4-mm form factor, while SDCs are produced on a 24- by 32- by 2.1-mm form factor. Memory capacity depends on the design of the silicon die inserted into the memory card but typically holds 16 or 32 Mbytes. Stacking multiple memory chips into the card boosts this capacity to 128 Mbytes without increasing card dimensions. Cost depends on the number of memory die the customer uses.
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