New Silicon-Infused Bilayer Photoresist Developed by TOK and Dow Corning Electronics Being Used in IC Memory Production

Photoresist Provides Improved Etch Selectivity While Eliminating Hard Mask Layer For Simpler, More Cost-Effective Processing

MIDLAND, Mich., Dec. 3 - Tokyo Ohka Kogyo Co., Ltd. (TOK) and Dow Corning Electronics today announced that their new, jointly developed bilayer photoresist is being used in production for the first time by a leading manufacturer of DRAM chips. The new bilayer photoresist uses a Dow Corning silicon polymer in the imaging layer to provide better etch selectivity than other products on the market today.

Photoresist is a light-sensitive material that becomes either soluble or insoluble after exposure to light, allowing portions to be selectively removed during subsequent etching processes. Adding Dow Corning's innovative silicon polymer to TOK's photosensitive materials enables the use of thinner photoresist layers, which improves pattern resolution and allows smaller circuit patterns to be transferred onto target wafers without pattern collapse issues.

The new photoresist provides a more cost-effective lithography solution by eliminating the hardmask layer and accompanying process steps required by multilayer photoresist processes. It can be used for both dry and immersion lithography, an advanced imaging technology that is gaining market acceptance for the 45nm node and beyond. TOK has already demonstrated use of the photoresist under immersion lithography conditions to produce 35nm line/space patterns.

"Our partnership with TOK is paying off as chip makers realize the advantages of this new silicon-infused photoresist," said Tomonobu Noguchi, Electronic & Advanced Technologies marketing director with Dow Corning. "This breakthrough material represents a new class of photoresist, which is helping to extend the capabilities of 193nm lithography."

Dow Corning and TOK have had a joint development agreement since 2002 to develop advanced silicon-based photolithography materials. The collaboration combines TOK's sophisticated microprocess technologies and photolithography application expertise with Dow Corning's materials innovation and manufacturing capabilities. The lithography development work is being conducted at TOK's R&D facilities in Kanagawa, Japan.

About Tokyo Ohka Kogyo Co., Ltd. (TOK)

Tokyo Ohka Kogyo Co., Ltd. ( supplies an assortment of manufacturing materials centered around photoresist used in fabricating semiconductors, flat panel displays, printed wiring boards and semiconductor packaging, as well as photolithography-related chemicals. The company also furnishes equipment that is indispensable for fabricating leading-edge semiconductors, liquid-crystal-display panels and semiconductor packaging. In addition, TOK offers photopolymer plates and pre-sensitized plates, which are widely used in the printing field, as well as high-purity chemicals for use by the chemistry, electronics, pharmaceuticals, food products, and textile industries.

About Dow Corning

Dow Corning Corporation ( is a globally integrated provider of materials, application technology and services, and is focused on providing innovative technologies that help its customers to invent the future. For more information on Dow Corning Electronics, visit Dow Corning Corporation is equally owned by The Dow Chemical Company (NYSE:DOW) and Corning Incorporated (NYSE:GLW). More than half of Dow Corning Corporation's sales are outside the United States.

Source: Dow Corning Electronics

Rhonda Bovin
of Dow Corning,

Bruce Hokanson
of Loomis Group,

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