Sematech: 450mm program is on track

International Sematech is moving full speed ahead with its 450mm programs, but the question is whether the industry can meet its lofty goals in building 450mm fabs by 2012.

On July 9, chipmaking consortium Sematech provided an update on its next-generation 300- and 450mm programs, saying that they are on track and making steady progress.

The consortium is up and running with its "factory integration test bed" facility for the development of 450mm fab tools. Sematech is also testing silicon wafers based on 450mm technology. And the group claims it has made progress on its so-called "Next Generation Factory" (NGF) program, geared to bring lower costs and reduced cycle times in 300mm wafer manufacturing.

Recently, Sematech unveiled two next-generation fab programs: 300mmPrime and the International Sematech Manufacturing Initiative's ISMI 450mm effort.

Need for 450mm?
There is widespread support among the fab-tool community for 300mmPrime, which looks to boost the efficiency of existing 300mm fabs, thereby pushing out the need for 450mm plants.

The newer, more controversial ISMI 450mm program, announced last year at Semicon West, calls for some chipmakers to make a more direct transition from 300mm to the larger 450mm wafer size.

Many fab-tool vendors are reluctant to endorse the next-generation wafer size or devise 450mm tools, saying that it is simply too expensive. Many vendors claim that 300mm fabs are suitable for most applications and the real goal for the industry is to improve the productivity of current plants.

"There is still a lot of concern and debate" about 450mm fabs among the equipment makers, said Scott Kramer, VP of manufacturing at International Sematech, but "the tide has shifted over the last 12 months."

A few fab-tool and materials vendors have develop 450mm technologies, but many suppliers have publically slammed Sematech's 450mm program, saying the economics simply don't add up.

However, the mood is somewhat beginning to change, especially when Intel Corp., Samsung Electronics and Taiwan Semiconductor Manufacturing Co. Ltd in May reached an agreement on the need for industry collaboration for 450mm wafers starting in 2012. Intel, Samsung and TSMC indicate that the semiconductor industry can improve its return on investment and reduce 450mm research and development costs by applying aligned standards, rationalizing changes from 300mm infrastructure and automation, and working toward a common timeline.

Intel, Samsung and TSMC represent a major chuck of the world's capital equipment buyers. Because those companies are pushing for 450mm fabs, it could jumpstart the development of the next-generation wafer size.

Many believe that 450mm tools will not be ready in the 2012 timeframe. Even Kramer acknowledged that the 2012 timetable for 450mm fabs is "very aggressive."

"Those are risky goals," he said.

300mm vs. 450mm
To jumpstart the 450mm era, Sematech last year announced a plan to devise a "factory integration test bed" facility for the development of 450mm fab tools. The proposed facility would help enable chip-equipment makers to develop the initial fab-automation gear, such as carriers, load ports, modules and other items.

Providing an update on the "test bed," Tom Abell, 450mm program manager at Sematech, said the facility is operational. At present, Sematech has put the "test bed" at the Advanced Technology Development Facility, the consortium's former R&D foundry. Based in Austin, Texas, that facility was recently sold to SVTC Technologies Inc.

The facility is using the first 450mm handlers from Brooks Automation Inc. and carriers from Entegris Inc. The pitch specification for these tools is 10mm. With the fab-automation gear, Sematech has demonstrated a 450mm wafer running at 100,000 cycles, Abell said.

Sematech is also in the process of developing a standard for 450mm silicon wafers. At present, there are five wafer-thickness standards vying for dominance in the arena, each with their own set of "tradeoffs," Kramer said.

Initially, Sematech is exploring 450mm wafers with an overall thickness of 925-micron. Last year, Japan's Nippon Mining & Metals Co. Ltd claimed to have developed the first 450mm polycrystalline silicon wafers. Sematech is testing wafers from Nippon Mining, but the consortium is also talking to other silicon wafer suppliers, Kramer said.

NFG Program
The consortium also claims it has made progress on its 300mm NGF Program, which focuses on global infrastructure for 300mm hardware and software. It includes 300mmPrime and is supported by ISMI's four other programs in continuous improvement, 450mm manufacturing, metrology, and environment, safety and health.

"The 300mm NGF Program offers a wider look at 300mm productivity with a broader set of initiatives—and it works for companies whose business plans don't necessarily include a larger wafer size," said Kramer in a statement last year. "Our priority is to extend productivity improvements to existing 300mm fabs in addition to supporting 'green field' facilities."

The overall goal of the program is to reach a 30 percent reduction in cost per wafer, and a 50 percent reduction in cycle time. Like last year, Sematech said it has not been able to reach those targets.

In new simulation data, the consortium claims it is coming closer to its goals. It has simulated a 30- to 40 percent boost in cycle times and 10 to-15 percent improvements in cost. In other data, it has demonstrated a 60 percent boost in cycle times and a 10 percent improvement in cost.

The bottleneck remains in moving the wafer lots from one tool to another. The goal is to process wafers without any delays, according to Sematech.

- Mark LaPedus
EE Times