Tokyo Ohka Kogyo (TOK, 東京応化工業株式会社) is a company that manufactures and sells chemical and manufacturing materials. It operates in four areas: Semiconductor Manufacturing, Semiconductor Packaging Manufacturing, Image Sensor / MEMS Manufacturing, and Panel Manufacturing. The Semiconductor Manufacturing division provides EUV photoresists, KrF excimer laser photoresists, diffusing agents, etc. The Semiconductor Packaging Manufacturing division offers bump formation photoresists and RDL photoresists. The Image Sensor / MEMS Manufacturing division delivers photosensitive permanent film materials, microlens photoresists, and lift-off photoresists. The Panel Manufacturing specializes in adhesive materials. Tokyo Ohka Kogyo also provides non-photosensitive materials such as high-purity chemicals.