HSINCHU, Taiwan -- A rogue chip-scale package type is going to market next week with DRAMs inside, claiming reduced costs relative to standard TSOPs and twice the memory capacity in modules of a given size.
The nonstandard ball-grid array for 64-megabit DRAMs was developed by Kingmax Technology Inc. of Hsinchu, Taiwan, which builds DRAM modules using the packaging technology. The underlying TinyBGA technology upon which the DRAM package is based is available from Kingpak Technology Inc., also of Hsinchu, a supplier of IC assembly and test services.
The DRAM TinyBGA is four to five times less expensive in production than the industry-standard MicroBGA in DRAM applications, according to John Shu, memory product manager with Kingmax Micro Technology Inc., an Irvine, Calif.-based subsidiary. The company is not seeking to standardize the package, and most of its business is done at the module level. However, the company is working with some manufacturers of handheld computers -- and other systems where modules are not used and high DRAM density at low cost are key -- to get product designed in at the chip level, Shu said.
A laminate substrate is used as a base for the plastic-encapsulated 64-Mbit DRAM package, which measures 9 by 12 by 1.4 mm. Very short wire bonds help achieve a trace length only 25% of that of a thin small-outline package (TSOP). Inductance and capacitance are lowered, allowing higher operating speeds to be achieved -- up to 250 MHz.
Kingmax is discussing a transfer of the packaging technology with Micron Technology Inc., Boise, Idaho -- which is one of its major wafer suppliers -- but is not actively looking to sign up DRAM manufacturers to assemble their own products in TinyBGAs, according to Shu.
Instead, the company plans to leverage the package in its own modules, primarily, taking advantage of superior electrical, thermal, and size characteristics relative to TSOPs. The company makes both industry standard modules and proprietary types, and states that a given laptop computer can double its memory capacity in the same space using its products.
Emphasizing the TinyBGA's cost advantages, Shu said the company sells 133-MHz modules at prices competitive with 100-MHz modules on the market. He added that the company gets better yield from wafers it buys because the better electrical characteristics of the package permit more ICs to meet spec at a given clock rate.
"Kingmax has made a significant investment in the design and implementation of the TinyBGA technique, but the actual production costs are less than TSOP and we will pass on those savings to our customers," said Joseph Wu, vice president of Kingmax.
Kingmax's future plans include packaging 128- and 256-megabit DRAMs and a possible Rambus package using a flip-chip approach.