Making Waves in Microlithography
Consumer demand continues for lighter, faster electronic tools -- cell phones, palm organizers, laptop computers. Smarter microchips are essential "fuel" for these tools, requiring complex instructions to be etched on smaller and smaller media.
The semiconductor chips require precision microlithography to "write" features onto such media. Features pass through a "lens train" from the photomask (where the information is stored) to the wafer (where the information is written). Silica is a critical component for this "stepper" equipment used in the semiconductor manufacturing process.
Charlene Smith, a Corning senior research associate, and her team have dedicated themselves to developing next-generation solutions for Corning’s microlithography materials.
With her Ph.D. in Organic Chemistry from Colorado State University, Smith completed postdoctoral work for Oak Ridge National Laboratory. Smith’s academic research focused on organic and synthetic organic chemistry. While the postdoctoral work was compelling and had immediate impact on energy research, Smith wanted to broaden her knowledge base.
“I wanted to explore other scientific disciplines, building on the basics gained from what I learned in my academic research,” says Smith. “I was looking for research projects that posed more complexity with a solid intellectual payback. That’s why I became interested in materials technology.”
Corning provided the opportunity for Smith to apply her organic research skills and knowledge to the science of inorganic materials. She was equally attracted to Corning’s unique team approach to research where team members work together to leverage resources and innovate ideas.
Smith began her career in Science and Technology’s Polymer Research Group in 1990. One of her first projects was working on Placor, a glass-plastic composite material. “With the Placor project, I really saw the benefits of understanding the characteristics of key materials – whatever their application.” This “broader perspective” motivated Smith to move to glass and glass-ceramics research in 1993.
Today, Smith is recognized as an expert in the long-term laser damage behavior of fused silica materials. Her research efforts in deep UV transmitting materials (including HPFS®, single crystal fluorides and F-doped silica) have yielded measurable positive and profitable results for Corning.
In 2002, Smith teamed with Corning Research Associate Lisa Moore to create highly transparent photomask materials for microlithography applications. They modified the composition of silica by removing water and adding fluorine ions. The resulting innovation enables the transmission of wavelengths (157nm in particular) that the semiconductor industry thought were impossible with silica glass. This material is the only one that can be used for the photomask at 157nm lithography node.
Not only has this discovery “broken silica’s wavelength barrier,” it was a critical addition to the semiconductor lithography roadmap. The roadmap is used by the entire industry to chart future research priorities and the technological advances needed to support them.
“Predictable, precise, reliable manufacturing results are essential to maintain and expand market share in the semiconductor industry today,” suggests Smith. “Shorter product life cycles, near ‘zero defect’ manufacturing requirements and exploiting first-to-market advantages requires researchers to stay ahead of the curve.”
Smith is doing just that. She received the 2002 Stookey Award for her exploratory research leading to significant understanding of a new phenomenon in microlithography technologies. Smith’s research at Corning has resulted in 22 patents and applications as well as extensive publication in major scientific journals.
Smith continues to work on advances in glass and glass ceramics materials used in semiconductor applications. She currently serves as technical project leader in the development of single-crystal fluorides for photolithography.