Intel to use Tessera MBGA for flash

Electronic News, Dec 2, 1996 by Bernard Levine

Folsom, Calif.--Intel has taken a Micro Ball Grid Array (MBGA) chip-scale package license from Tessera, its developer, and will use the MBGA for flash memory, confirming earlier reports (EN, Antenna, Nov. 25). A number of leading IC makers, including Intel, Advanced Micro Devices and Texas Instruments, have reportedly been scrutinizing Tessera's MBGA in recent months and eyeing licenses (EN, Sept. 16; Antenna, Nov. 11). TI has also reportedly taken a license in recent weeks to use the MBGA for memory products.

San Jose, Calif.-based Tessera has already licensed about a dozen other U.S. and Asian firms to either assemble chips in the MBGA package or to produce the tape used in the assembly process, trying to build an infrastructure around its technology. Intel has taken a full license covering all parts of the technology, one of a dozen or more competing chip-scale approaches vying against each other for expected high-volume future use. Intel's embrace and the other recent interest are expected to give Tessera's MBGA a major leg up. Chip scale, considered a traditional packaging technique, is expected to compete against various, more exotic bare die alternatives, as well.

Intel last week low-keyed the Tessera connection, with its official press release saying it was adopting the MBGA package "as part of its packaging portfolio for future flash memory devices," but not identifying the package's developer by name, although Tessera was included in a list of industry endorsers of the MBGA. The Intel release also avoided any mention of licensing implications, but Intel officials confirmed the Tessera license when questioned, although declining to provide details.

Tessera, however, began its statement on the deal with "Intel Corp. will employ Tessera's proprietary chip-scale packaging technology in its semiconductor devices under a newly-signed license agreement," but also did not disclose terms. John W. Smith, Tessera president/CEO, claimed: "The close relationship that Intel and Tessera formed over the past year will certainly accelerate the rapid, worldwide acceptance of the MBGA package."

Intel noted the package is available from a variety of sources, all Tessera licensees. Intel will make some of the MBGA packages itself and go to outside foundries for others, but would not give specifics. While Intel has chosen MBGA over bare die approaches for flash, and also recently emphasized conventional packaging in plans for its next-generation Klamath processor (EN, Nov. 18), the company remains committed to bare die approaches for other applications, company officials indicated last week. Intel also remains fully committed to its SmartDie program, they said, which sells bare die and has been a major boon to bare die proponents.

For flash, however, Intel heaped praise on the MBGA, noting various advantages including its compatibility with current surface mount assembly. "The smallest flash memory footprint package available, MBGA technology will enable smaller, thinner, lighter products such as cellular phones, handheld communications and computing devices and PC cards," Intel said, adding it will implement the package next year on selected flash component products.

"The MBGA package, a true die-size package measuring 1 millimeter thick, provides significant board space and height savings over traditional surface mount packaging alternatives. For example, an 8-megabit, 0.4-micron flash memory using a 5x8 ball matrix MBGA package is 80 percent smaller and 17 percent thinner than its 40-lead TSOP (thin small outline package) counterpart. The MBGA package's relaxed 0.75mm (about 30 mil) ball pitch and low ball count enable cost-effective, single-layer printed circuit board design using standard trace/space rules. The PCB footprint is smaller than the package itself, thereby simplifying trace routing," Intel said.

"MBGA packaging provides flash memory customers with a cost-effective, rugged solution for portable consumer devices," Intel added. "The self-aligning 0.75mm ball matrix ensures consistent placement and reliable solder joint integrity." Also, according to Intel, the MBGA will allow customers to leverage existing, installed surface mount assembly equipment in their manufacturing lines, providing a cost-effective transition for current users of other fine-pitch packages such as QFP (quad flat packs) and TSOP. The MBGA package also integrates a flexible elastomer between the flash memory die and the PCB, providing wide temperature variation tolerance, it was said.

Richard Foehringer, director of packaging development for Intel's Memory Components division here, noted the MBGA is a "chip-size package," the same size as the die, unlike some other chip-scale designs, which are larger. He claimed various size and other advantages over competing packages such as SON from Fujitsu and ball grid arrays (BGAs).

Jedec has accepted a standard for MBGA specs proposed by Intel, AMD and Tessera, and approval is now being sought from the Electronic Industries Association (EIA) in the U.S. and the Electronic Industries Association of Japan (EIAJ), Intel officials indicated.