Chip Scale Packaging / Rambus DRAM convergence: The DRAM ante is being upped. This may artificially reduce future supply temporarily, from EETimes:
Posted: 11:45 p.m., EDT, 8/21/98
Rambus sees possible shortage of chip-scale packages in '99
By Terry Costlow and By David Lammers
NEW YORK - Chip-scale packages (CSPs) could be in short supply
next year if its Direct Rambus DRAMs (D-RDRAMs) are quickly
adopted, warned Rambus Inc. chief executive officer Geoff Tate.
Rambus said it hopes that its 10 RDRAM licensees will ship between
100 million and 200 million D-RDRAMs next year. For density and
electrical reasons, Rambus designed its D-RDRAM with chip-scale
packaging, but few of Rambus' 14 DRAM partners have installed
volume CSP production capability, Tate said.
Concern about a possible shortage in CSPs was shared by Paul
Hoffman, vice president of advanced development at Amkor
Electronics Inc. (Chandler, Ariz.). "We're producing 300,000 to
400,000 CSPs per week, probably second in the Tessera-style parts,"
he said. "We're meeting demand, but we're doing SRAMs and flash
memory, not DRAM. When demand for Rambus chips kicks in, there
could be a situation where there are shortages for a while."
Chip-scale usage is growing sharply because the technology provides
significant decreases in size, yet is still easy to handle. CSPs are only
1.2 times the size of ICs or smaller, and consume far less space than
any alternative other than flip chip. They come lightly coated in
protective material, which makes them somewhat larger but easy to
handle. Smaller flip chips require special handling equipment because
the dice are unpackaged.
Tate said the CSP approach is currently about 50 percent more
expensive than a TSOP (thin small-outline package). Packaging
accounts for about 10 percent of the cost of the finished chip, so the
CSP premium is about 5 percent. That should disappear in several
years, he said, arguing that the tiny BGA package is "fundamentally no
more expensive than a TSOP."
Samsung Electronics uses CSPs for its flash production in Korea, and
Fujitsu Ltd. also uses the microBGA-type CSPs for flash chips used in
cellular phones and small systems.
Hyundai Electronics' packaging subsidiary, ChipPac Inc. (Santa Clara,
Calif.), is installing volume CSP capability. ChipPac has announced
plans to drop costs from around 2 to 3 cents per I/O to 1 to 1.5 cents
by the second half of 1999. Though ChipPac is reportedly being spun
off as the Korean company struggles for cash, it highlights the fevered
pace in CSP. It was set up as an independent company last September
when it became clear there was too much activity to leave it as part of
another Hyundai operation.
"For the DRAM companies that don't also have flash production
capability, CSPs present more of a learning curve," said Tate. During a
round of meetings with investors and the media here, he said Rambus is
characterizing the D-RDRAMs from four early producers: LG
Semicon, NEC, Samsung and Toshiba. The initial goal is to get the
Rambus modules, or RIMMs, ready for the early adopters that seek
their faster performance. Intel expects system companies to begin
shipping desktops with the Rambus architecture sometime in 1999.
However, Tate said price is as important as performance. The
RDRAMs have 72 pins, or BGA-type I/Os, and the number of pins on
the memory controller can be far less. Using wide buses to get
equivalent performance with SDRAMs increases the controller package
to more than 500 pins, Tate said.
For a year analysts have been saying that manufacturing capabilities
might lag behind demand, and the quick takeoff of yet another major
program will only increase the potential gap.
"Capacity is the big issue for chip-scale packages," said Jan Vardaman,
president of TechSearch International (Austin, Texas), a consulting
company. "The biggest problem with the microBGA from Tessera has
been capacity. Fortunately, a lot more has come on line lately. Still, Intel
and Rambus could dominate the entire microBGA capacity."
Even without the new thrust in this type of memory, CSP use is
skyrocketing. Intel and AMD have been packaging their flash chips in
CSP for a year or so, and the number of system makers who have
adopted that package is rising quickly. AMD uses technology
developed by Fujitsu, and that's helped push Fujitsu's volumes up
quickly.
"I would guess our production has gone up five times from 18 months
ago," said Dennis Stephenson, director of advanced packaging
technology at Fujitsu Microelectronics Inc. (San Jose, Calif.). "The big
driver is wireless mobile communications. Every cell phone made in the
last year has several CSPs, and there are lots of little CSPs in
convergence products like the Pilot."
Intel's flash chips, like Rambus memories, are packaged in the
microBGA developed by Tessera (San Jose). Though that package has
been around for years and is licensed by several manufacturers,
volumes are still emerging. Of Tessera's 29 licensees, so far only those
who provide Intel with the packages for its flash products have gone to
volume production.
Fujitsu makes 12 CSPs for different applications. Companies like
Fujitsu and Sharp that make both chips and packages appear to have
taken the volume lead, with help from licensees.
"The volumes today are in non-Tessera packages," Vardaman said.
"There are tons of things other than memories. There are TI's DSP
chips, lots of ASICs, some controllers. Plus, there are memories from
several companies like Sharp that aren't in Tessera microBGAs."
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