Tokyo Ohka Kogyo (TOK)
A photoresist specialist founded in 1940, supplying resists for every lithography generation from g-line and i-line to KrF, ArF and EUV, together with high-purity process chemicals.
東京応化工業・Materials・Last updated: October 15, 2026
Overview
TOK is headquartered in Kawasaki, Kanagawa. Its main domestic operations are in Samukawa, Kanagawa, and it also has a plant in Aso, Kumamoto.
Besides photoresists, TOK supplies developers, strippers and other high-purity chemicals used around the lithography step.
Business: Photoresists and high-purity process chemicals
Why it matters
TOK is a pure-play lithography materials company, which makes it a direct way to follow resist demand.
Its Kumamoto plant is part of the materials base around the Kyushu fab cluster.
Main products
- •Photoresists (g-line, i-line, KrF, ArF, EUV)
- •High-purity process chemicals (developers, strippers)
Sites in Japan
Head officeHeadquarters
Kawasaki, Kanagawa
Sagami and Shonan operationsSite
Samukawa, Kanagawa
Aso plantPlant
Aso, Kumamoto