Study Examines Changing Face of NGL

Although optical lithography has — despite the odds — remained the semiconductor industry's workhorse for a considerably longer time than repeatedly predicted, the quest for a winning next-generation lithography (NGL) contender has continued unabated. A new report from Frost & Sullivan (Palo Alto, Calif.) details the trends and adoption factors influencing microlithography's development.

With the report, "Global Advances in Semiconductor Microlithography Technologies," the growth consulting company aims to address the new and rapid developments of various lithography techniques, and identify the signs and breakthroughs that will propel a given technology to win the NGL race. The research is particularly useful for companies that are contemplating upgrading their lithography tools for the cutting-edge technology nodes," said Jayson Koh, an industry analyst for Frost & Sullivan in Singapore. "In addition, tool manufacturers such as resist and source suppliers can also benefit from the research through understanding the latest trends."

The semiconductor and related industries (e.g., MEMS), driven by different commercial interests and application needs, is divided into different camps. This study is an update on previous research performed in 2004, looking in-depth at such techniques as extreme ultraviolet (EUV), electron projection, immersion, X-ray, ion beam, maskless, nanoimprint and dip-pen lithography. It examines how, over the past three years, old issues have been resolved and new issues have been raised, while some NGL candidates have been dropped.

The research focuses on the remaining NGL technologies, looking at developments in lithography tools, analyzing key technology drivers, and evaluating the challenges that must be overcome for each NGL technology. The study also discusses the strategies that the various lithography solution providers have pursued.

Although the NGL limelight is on EUV and maskless techniques, Koh said, there are still a few researchers and companies working on X-ray and ion-beam lithography. "X-ray suffers from poor reduction capability, masking materials (strain building up easily), etc., which are difficult to solve, but X-ray is attractive in terms of resolution and having less spurious scattering effects," he said. "Ion beam is a slow technique, just like electron beam."

Dip-pen lithography also remains a part of the report's NGL consideration. "Dip-pen is a promising technology, especially for nanotechnology applications, but there is a lot of work to be done to popularize it," Koh said. "Specifically, NanoInk needs to increase the speed or throughput by many folds. One way that many people foresee is by putting many pens together, covering a huge area in every dip, but that will compromise the resolution. It's a delicate balance that they have to manage."

Koh added that there is no indication that dip-pen lithography will emerge as a mainstream solution in the near term. "However, I can see increasing applications of nanotechnology. And with this trend growing steadily, the demand for a dedicated nanolithography tool may surface, and dip-pen will certainly give nanoimprint a run for its money."

Manufacturers are reluctant to switch to a new lithography technology unless absolutely necessary. Nonetheless, the moment will ultimately arise when photolithography tools — even immersion tools — can no longer support volume production. Challenges such as rising mask costs and resolution limits make it difficult to sustain the current technology. As the report points out, a mask set costs ~$800,000 at 90 nm and $1.2M at 65 nm, with this trend making a 45 nm mask set likely to cost more than $2M. Meanwhile, existing immersion lithography techniques represent more than one-third of chip manufacturing costs — a percentage that continues to increase with each process technology generation.

Frost & Sullivan's research service offers information on organizations, companies, universities, research institutions and government labs involved in the R&D of the NGL technologies. Several emerging semiconductor microlithography techniques are introduced in a straightforward way. Both commercial and technical concerns with regard to each technology are discussed by examining practical and pragmatic applications so that readers can understand the situation.

The research not only examines the best practices and other qualitative aspects of organizations in the lithography industry, it also provides information on the relevant drivers, restraints and challenges within the major technology sectors. A summary of key patents gives insight into notable activities, technology trends and major players in the field.

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