Tokyo, JAPAN - Asahi Glass Co., Ltd. (AGC, Head Office: Tokyo; President: Shinya Ishizu) announced today that it has succeeded in developing a high-transparency fluoropolymer as a photoresist base polymer capable of use with an F2 (fluoride dimer) excimer laser, a leading candidate for next-next-generation semiconductor manufacturing.
A Japanese government-sponsored project aimed at developing fundamental technologies for next-next-generation semiconductors gets under way in April of this year, as a joint effort by government, industry and academia. An important part of that research will be to realize enhanced photolithography techniques supporting the extremely fine line widths of future semiconductors. Current road maps anticipate that following the KrF (krypton fluoride) excimer lasers currently used for line widths in the 0.18 to 0.13 micron (a micron= one millionth of a meter) range, ArF (argon fluoride) excimer lasers will be used for the next-generation devices in the 0.13 to 0.1 micron range. F2 excimer lasers are then expected to be used for the next-next generation devices in the 0.1 to 0.07 micron range, with mass production to be achieved by around 2005. Fluoropolymers are seen as the material best suited for transmitting an F2 laser beam with its 157 nanometer wavelength (a nanometer is 1/1,000,000,000 meters). Various such materials have been proposed by researchers to date.
The development announced today was carried out with the cooperation of Selete (Semiconductor Leading Edge Technologies, Inc.), and is based on the 0.07 micron line width development road map that is a theme of the Project Asuka collaborative development program.
Asahi Glass currently supplies a wide lineup of fluoropolymer materials to the semiconductor industry for use in their manufacturing systems, including PTFE, PFA and ETFE products, as well as the transparent fluoropolymer Cytop® for pellicles (photo mask covers) used with KrF and ArF excimer lasers. Building on the fluoropolymer design technologies fine-tuned in the process of creating those products, the newly developed fluoropolymer was devised by introducing fluoride atoms in the main chain of the polymer molecule. It has been appraised by Selete as having "an absorption coefficient of 1.5 mm-1 or less for 157 nm light, dry etching resistance comparable to ArF, and solubility in standard developer solution", and thus has excellent potential for use as a substrate material of a positive (one developed by removing the exposed areas) single-layer resist used with F2 excimer lasers. Samples will next be supplied to photoresist manufacturers so they can collaborate with Asahi Glass in developing new photoresist formulations.
Worldwide demand for photoresist used in semiconductor manufacturing amounts to in excess of 80-90 billion yen (7-8 billion dollars) per year, of which more than half is supplied by Japanese firms. Asahi Glass, while carrying on cooperation with photoresist makers, plans to have in place the full development and manufacturing capacity to meet this demand by the time F2 laser lithography ramps up around 2005.
Asahi Glass intends to continue developing new fluoropolymer materials for the IT industry, building on its existing know-how and expanding the fluoropolymer business into a core of its chemical products.
< For reference >
An F2 (fluoride dimer) laser emits a beam with a wavelength of 157 nm, by electrical discharge in compressed fluoride gas.
2. Excimer laser
Today's advanced semiconductor products such as dynamic random access memory (DRAM) chips of 64 Mb and above require a line width of 0.25 microns or less. The excimer laser produces the electron beams used in steppers (reduction-projection exposure systems) that are key to today's leading edge and next-generation semiconductor manufacturing. Generating a beam mainly in the deep ultraviolet range, this high photon energy laser is finding increasingly important application to semiconductor process technology and photochemical reactions.
Photoresist is a thin film of light-sensitive polymer material formed on a semiconductor wafer. The circuit pattern is transferred to this film from a glass mask in the lithography process.
Semiconductor Leading Edge Technologies, Inc. (Selete) is a research consortium formed in 1996, with equal funding by Fujitsu Limited, Hitachi, Ltd. and eight other Japanese semiconductor manufacturers. Its role is to evaluate next-generation semiconductor manufacturing systems and materials, and to conduct research on leading-edge core technologies for use in semiconductor manufacturing.
5. PTFE, PFA, ETFE, transparent fluoropolymer Cytop®
PTFE (polytetrafluoroethylene) is a fluoropolymer material with excellent properties, inert to nearly all chemicals and solvents.
PFA is a perfluoroalkoxy fluorocarbon polymer prepared using a perfluoroalkyl vinyl ether monomer. It is a melt-processable thermoplastic with durability and chemical resistance similar to that of PTFE.
ETFE (ethylene tetrafluoroethylene copolymer) is a fluoropolymer with excellent workability, chemical resistance and durability, as well as non-sticking and non-combustible properties.
Transparent fluoropolymer Cytop®
In 1990 Asahi Glass was the first company worldwide to develop the transparent fluoropolymer Cytop®. It features far greater transparency to visible light than acrylic or polycarbonate resins. Cytop® is already used in the plastic optical fiber product, LucinaTM .
- Asahi Glass Co., Ltd.
- TEL: +81-3-3218-5496