Beefing up 300 mm wafer fabrication in a bid to boost supply capacity

Elpida Memory, recognized as the world's "DRAM technology leader", has begun mass production of DDR2 SDRAMs using world-leading 70 nm process technology. By leading the way in miniaturization to reap the dual benefits of improved device performance (faster speed, lower power consumption, etc.) and higher productivity, Elpida is starting with DDR2 SDRAMs and will later deploy this technology in DDR3 SDRAMs, for which demand is expected to soar starting in 2008. This will give a big boost to Elpida's position in DRAM markets for PCs and servers.

In December 2006, Elpida Memory announced that it had launched mass production of 1 Gbit and 512 Mbit DDR2 SDRAMs using a 70 nm process. While competitors were still turning out products with 90 nm to 80 nm process technology, Elpida became the first to introduce 70 nm process technology into its mass production system. Elpida's advance was a particularly noteworthy event in the semiconductor world because the company had been using 90 nm process technology for its main products before skipping the 80 nm process step to go directly to the 70 nm process for mass production of its strategic products. One force behind Elpida's fast-paced miniaturization is the challenge to more quickly provide products that meet market requirements. For example, major manufacturers of microprocessors are seeking to accelerate data transfer between processors used in high-end PCs from the conventional rate of 667 Mbps (megabits per second) to 800 Mbps or even 1 Gbps. Yasushi Takahashi, a corporate officer in Elpida Memory's Server & PC Division, notes that "when we took our process technology from 90 nm to 70 nm to speed up circuits, the data transfer rate can be boosted from today's 667 Mbps (maximum is 800 Mbps) to 1 Gbps while keeping the DDR2 specifications" (see Figure 2). With the introduction of Windows Vista late last year, more main memory is being installed in PCs. "Notebook PCs don't have much space for adding memory, so that is where smaller, higher-capacity DRAMs are most needed. Notebook PCs also require lower power consumption." As miniaturization continues, we will see progress made both in raising capacity and lowering power consumption (see Figure 3)

Mr. Yasushi Takahashi Corporate Officer, Server & PC Division Elpida Memory, Inc.

By getting a jump on its competitors in providing products to meet these market needs, Elpida hopes to widen its share of the DRAM markets for PCs and servers. "One big part of Elpida Memory's business is high value-added 'Premier DRAMs' for mobile phones and digital consumer electronics products. Meanwhile, there is still ample room for expanding market share in DRAMs for PCs and servers, which are also big markets. Actually, we already have a 15 to 20 percent share of the server DRAM market, but our percentage of the DRAM market for major PC manufacturers is still in the single digits. We intend to use our leading position in miniaturization to grow our server DRAM market share to 30% and to get our share of DRAMs for major PC makers up to 15% as soon as possible, as we vie to become the top manufacturer in the DRAM market." Takahashi added.

Using the 70 nm process to enter the DDR3 market

As an early adopter of 70 nm process technology, Elpida is seeking to take advantage of its position to develop business in DDR3 SDRAMs, where demand is expected to pick up starting this year, and the company will be particularly keen to expand its market share in DRAMs for PCs and servers. DDR3 SDRAMs support data access rates from 1 Gbps to 1.6 Gbps, much faster than the 533 Mbps to 800 Mbps range that is typical of DDR2 SDRAMs. In the second quarter of 2007, U.S.-based Intel Corporation is expected to begin marketing a chipset for microprocessors that support DDR3 SDRAMs.

Elpida Memory estimates that while DDR3 SDRAMs will account for only 1% or 2% of the PC/server DRAM markets in 2007, this percentage will grow to approximately 20% in 2008 and over 50% in 2009. According to Takahashi, "Our lead in miniaturization better enables us to provide the faster circuits required by DDR3. We have already sent Intel samples of DDR3 SDRAMs fabricated using a 90 nm process, and evaluation of the technology is under way. Backed by our know-how in this area plus our 70 nm process technology, we will be able to meet market needs for DDR3 SDRAMs in a timely manner."

(a)  1 Gbit (x8 and x16) DDR2 SDRAM packages	(b) Photo of 512 Mbit DDR2 SDRAM chip fabricated using 70 nm process

Figure 1 •The World's First to Introduce 70 nm Process for Mass Production

Building up 70 nm and 300 mm production

While working to achieve a higher position in the PC/server DRAM market, Elpida is also seeking to reinforce its production capabilities. "Up to now, our production system has not been primed for pursuing the top share of the market. But now we are adding 300 mm wafer fabrication lines and have introduced 70 nm process technology, which should give a huge boost to our production capabilities" says Takahashi. In addition, a new mass production line will start up in the third quarter of 2007, to be operated by DRAM manufacturer Rexchip Electronics Corporation, a joint venture between Elpida and Taiwan's Powerchip Semiconductor Corporation (PSC). Rexchip's fabrication plant will include lines that support 300 mm wafers and 70 nm process technology, and will focus mainly on manufacturing DRAMs for PCs, to the tune of at least 30,000 wafers per month by the end of the 2007 fiscal year. Half of these DRAMs will be turned over to Elpida Memory. Elpida is also expected to outsource increasing amounts of production to PSC. Altogether, Elpida Memory's DRAM production for PCs and servers is expected to reach the 100,000-wafer-per-month mark (with 300 mm wafers) before its 2007 fiscal year ends.

Takahashi explains, "Let us say that, using our 70 nm process, we can make about one thousand 512 Mbit DRAMs from each wafer. So, if we get our production capacity up to 100,000 wafers per month, that means we will be able to make about 100 million 512 Mbit DRAMs per month." Generally, the global industry now makes from 500 to 600 million DRAMs for PCs each month. So, if all goes well, Elpida's production system should be able to supply 15% to 20% of this global output by the end of FY2007.

Introduction of 70 nm process technology into current fabrication

How has Elpida managed to bring 70 nm process technology, a key for future business expansion, into its mass production system so early on? One major reason is the company's highly efficient, mass production-focused R&D organization. Elpida's 70 nm process is the result of widespread application of low-voltage device technologies, high-speed wiring technology, and the like. These technologies have been developed by Elpida's Technology & Development Office. This division uses production lines when developing leading technologies so that its R&D results can be deployed in mass production sooner.

The process technology established by the R&D division is deployed, while working with our mass-production plants, by engineering departments under Elpida's various corporate divisions, which are organized around product categories. By working positively to apply and verify new technologies with existing mass production processes, the company can speed up the process of acquiring the required knowledge and achieving results in mass production using each technology.

Says Takahashi, "almost all of the new process technology that has gone into our 70 nm process is built on the results deployed in products made using our 90 nm process technology. You could say that our 70 nm process technology is a new technology that stands on the shoulders of our success in the 90 nm process." Today, Elpida Memory has been reinvigorated as it makes its 70 nm process mass production a foothold for a climb to the top of the DRAM market, an ascent that will be interesting to watch, every step of the way.

Figure 2•Using 70 nm Process for Faster Operation (Example Is 1 Gbit DDR2 SDRAM)

Figure 3•Using 70 nm Process for Lower Power Consumption (Burst Mode)