Tokyo Ohka Kogyo Co., Ltd. (TOK) provides chemical products, such as photoresist, and equipment needed to manufacture semiconductors and flat panel displays (FPD).

When was Tokyo Ohka Kogyo established?

We trace our start to the Tokyo Ohka Kenkyujo (Applied Chemistry Laboratory), which was founded in 1936. The joint-stock company Tokyo Ohka Kogyo (TOK) was established in 1940, and celebrated its 60th anniversary in 2000.

When was TOK listed?

Our stock was listed on the Second Section of the Tokyo Stock Exchange in July 1986, and was transferred to First Section in September 1990.

What is TOK's local code at the Tokyo Stock Exchange?

TOK's local code is 4186.

What is the contact party for various stock procedures such as transfer and succession?

Mitsubishi UFJ Trust and Banking Corporation. For more information, click here (Mitsubishi UFJ Trust and Banking Corporation Homepage / Japanese Only)

What is the minimum number of stocks allowed per trade?

It is 100.

When does TOK announce its business results?

Each year, we announce the first quarter business results between beginning and mid August, the interim business results between mid and late November, the third quarter business results between beginning and mid February, and the term-end business results between mid and late May. For more information, click here.
Financial statement data and other such information are posted on this website.

Where is financial information available for perusal?

Click here for highlights, trends, and Tanshin, and click here for the webcast of presentations.

What business is TOK engaged in?

We supply an assortment of manufacturing materials centered around photoresist used in fabricating semiconductors, flat panel displays, and printed wiring boards, as well as the photoresist-related chemicals. We also furnish equipment that are indispensable for leading-edge microprocess of fabricating semiconductors and liquid-crystal-display panels. In addition, we offer photopolymer plates and pre-sensitized plates, which are in widespread use in the printing field, as well as high-purity chemicals for use by industries in the fields of chemistry, electronics, pharmaceuticals, food products, and textiles.
Click here for information on materials and equipment for semiconductors, flat panel displays, and printed wiring boards manufacturing; here for information on printing and plate-making materials; and here for information on high-purity chemicals.

What is photoresist?

Photoresist is a kind of resin with a chemical action and change in response to light, and is also known as photosensitive resin. It is in extensive use as a material essential for microprocessing in fields such as semiconductors, flat panel displays, and printed circuit boards.

How does photoresist change when it is irradiated with (exposed to) light?

Undergoing the process of development after exposure, the exposed portion of negative tone photoresist is retained as an image, and the unexposed portion of positive tone photoresist is retained as an image.
Photo.1 was taken after exposure and development, and shows photoresist retaining an image of the portion shown by the red arrow.

What are the types of photoresist?

The main types are a liquid type and a dry type. The dry type takes the form of a thin film and is called "dry film resist".
Mainly the liquid type is used in the field of semiconductors and liquid crystal displays (LCDs), and mainly the dry type, in that of plasma displays (PDPs) and printed circuit boards.

What is the role of photoresist?

Photoresist is used for processing with chemicals, for example. In this processing, the image portion remains unaffected by the chemicals, such that only the other portions are etched or otherwise processed.
In Photo.2, the red portion will be processed while the blue portion will be protected by the photoresist and left unprocessed. Application of photoresist therefore enables selective processing.