Latest Memory Activity in Japan

Jun Takahashi, SI Japan -- Semiconductor International, 7/19/2007

The Japanese semiconductor market depended on the growth of the memory manufacture — Toshiba’s NAND flash memory and Elpida’s DRAM — in fiscal 2006. “Elpida started 70 nm production in December 2006. Right now, the capacity is 20,000 wpm (300 mm) and is expected to expand to 65,000 wafers within this year,” said Jiro Yamamoto, director and plant manager of Hiroshima Elpida Memory (Hiroshima, Japan), a subsidiary of Elpida Memory (Tokyo). Yamamoto emphasized that the success of 70 nm implementation is because the R&D line was set closer and parallel with the production line, securing a certain amount of wafers for the R&D team. It perfected Elpida’s advanced technology before the generation began. He also noted that the company focused on reducing cycle time. In the past, time between mask to mask was more than two days, but now it is better than some of the faster logic manufacturers, which is 1.5 days per mask.

Hiroshima fab capacity is 20,000 wpm. (Source: Elpida Memory)

As Yamamoto mentioned, metrology tools and lab equipment are getting closer to the fab. At SEMICON West, Hitachi High Technologies (Tokyo) will display a banner that says, “Next Dimension Now,” as the company introduces its automatic defect review and classification system RS-5000 defect review SEM for high-volume wafer manufacturing. The system uses advanced defect detection algorithms to achieve higher throughput and capture rate. Hitachi will also introduce a design-based metrology system, which simplifies and accelerates complex metrology tasks when paired with the company’s CD-SEM. It is the only system capable of pre-identifying pattern recognition sites with no wafers or tool time required, according to Hitachi.

We can also expect to see many launches of new equipment focusing on high throughput, and tough applications related to the implementation of new materials. Dainippon Screen Mfg. (DNS, Kyoto, Japan) has developed a high-throughput 300 mm single-wafer cleaning system. It incorporates a newly developed high-speed wafer transfer system for an achievable throughput of 300 wph.

Hitachi Kokusai Electric (Tokyo) will launch resist strip tools to the U.S. market for the first time at the show, including a platform for 65/45 nm 300 mm wafer photoresist stripping. The unique plasma chamber design aims to reduce damage to gate oxides or other FEOL and BEOL processes. It was only offered to limited users previously. Also, Hitachi Kokusai said that the batch atomic layer deposition (ALD) tool has demonstrated success in Japanese and U.S. markets.

Inside the 70 mm DRAM fab. (Source: Elpida Memory)

Expectations toward new application, such as MEMS, are continuously expanding. Tokyo Electron Ltd. (Tokyo) will showcase a new tester combined with the company’s wafer probers. Temeon is a system designed to test and evaluate both the electrical and previously untested mechanical characteristics of MEMS devices at the wafer level by applying a new local vibration stimulus input.

Phase-change memory (PRAM) is on the way to the market. Ulvac (Tokyo) is planning to launch a film deposition tool for PRAM manufacturing. Elpida is in the process of testing the production of PRAM on a 200 mm wafer with a 100 nm process.