January 17, 2002Products

Increasing Production Capacity of large-sized TFT-LCD Glass Substrates

- Responding to growing demand for use in large LCD TV sets -

Tokyo, JAPAN - Asahi Glass Co., Ltd. (AGC, Head Office: Tokyo; President: Shinya Ishizu) announced today that it has succeeded in using a high-transparency fluoropolymer, a leading candidate for next-next generation photolithographic semiconductor manufacturing using F2 (fluoride dimer) excimer lasers, as a photoresist base polymer in a 250nm film (one nm, or nanometer, is 1/1,000,000,000 meters), to create the world's first 100nm-width fine pattern (1:1 line-and-space).

The company has been following the development roadmap agreed under the Project Asuka private-industry collaborative program with its theme of developing 0.07-micron line-width semiconductors (a micron, or µm, is 1/1,000,000 meters). AGC successfully developed, in February of 2001, a high-transparency fluoropolymer as a photoresist base polymer for use with F2 lasers. Subsequently, working with Selete (Semiconductor Leading Edge Technologies, Inc.), various evaluations of its viability as photoresist have been performed, including its development characteristics, resolution and suitability for dry etching and "spin-on" coating.

The most difficult technical challenge in the practical implementation was to use an F2 laser in actual photolithography to form fine patterns in resist coatings 200 to 300nm thick. AGC successfully designed and synthesized the new high-transparency fluoropolymer to achieve an absorption coefficient of less than 1.0 µm-1 for 157nm light. Since then, Selete has evaluated the new fluoropolymer as capable of forming a 100nm fine pattern in a practical 250nm coating (see accompanying photomicrograph). The fluoropolymer has an extremely high development sensitivity of less than 10mj/cm2 (mj = millijoule), confirming that it possesses most desirable characteristic for the formulation of highly sensitive photoresist materials (see accompanying figure).

AGC currently supplies industry with fluoropolymers including PTFE for semiconductor manufacturing facilities, and itself manufactures and supplies an 80% share of the transparent fluoropolymers for pellicles used in photo mask covers with KrF lasers. It has also begun high volume production of Cytop® for pellicles with next-generation ArF lasers. The company is exploiting its core capabilities in fluorochemical engineering to provide a wide lineup of fluoropolymers.

Worldwide demand for photoresist used in semiconductor manufacturing is put at 80 to 90 billion yen (6 to 7 billion US dollars) per year. AGC is working to provide timely samples to resist producers, production equipment manufacturers and device makers by boosting its prototype production facilities in time for spring, 2002, while simultaneously preparing to strengthen development work and expand production capacity in time for the expected start-up of F2 laser production in 2005 and for the roll-out of high-volume production in 2007.

For reference


Line and space
This is one of the types of photoresist patterning used in lithography, the process by which exposure to light is used to transfer circuit patterns from a glass mask to a semiconductor wafer. The size of the line and space is proportional to the gate pitch and the degree of integration.


Selete (Semiconductor Leading Edge Technologies, Inc.)
Currently, this company is under contract to 13 semiconductor manufacturers to develop device processes over the five years 2001 through 2005 with an investment of 70 billion yen. From 2002, it will relocate to the super clean room (SCR) currently under construction at Tsukuba City, where its development activities are planned to take place. The SCR will be in a research building for cooperative projects involving government, industry and academia owned by the National Institute of Advanced Industrial Science and Technology, an independent government research institute.


The Asuka Project
This is a cooperative commercial development project intended to solve problems in semiconductor design and wafer-forming processes for which no methods currently exist. Starting in April 2001, and planned to take five years at an overall cost of 76 billion yen, its objectives include the development of 0.1 to 0.07 µm system-on-chip design and device-process technologies.


Development, resolution, sensitivity.
These are all characteristics important in photoresist materials. Development is particularly important for positive resists, as it determines how much of the pattern being illuminated can be removed. Resolution determines the precision with which narrow line and space patterns can be implemented. Sensitivity indicates the intensity of laser light needed for a given patterning exposure; smaller numbers indicate higher sensitivities.


Absorption cooefficient
This coefficient is a material characteristic that indicates the extent to which the material absorbs light; the smaller the coefficient, the more easily light passes through the material.

Photomicrograph : Profiles of 100nm and 95nm line-space patterns in 250nm film

(Levinsohn mask)

100nm L/S 95nm L/S
Profiles of 100nm Profiles of 95nm

Figure : Degree of Development

Degree of Development : 10.0 mJ/cm2

Degree of Development

Contact :
Asahi Glass Co., Ltd.
Mr. Akihiko Ninose
Corporate Communications Division
F a x : 81-3-3201-5390
TEL: 81-3-3218-5915