The three other companies are Fujitsu, NEC Electronics and Renesas Technology, a joint venture between Hitachi and Mitsubishi Electric.
The companies are looking to possible mutual use and consolidation of their plants in the future.
Analysts have said Japanese chipmakers need to join forces to regain competitiveness and better compete with, Samsung Electronics and Texas Instruments.
. It also cuts production costs per chip. But , making it difficult for chipmakers to shoulder the burden alone.
A nanometer is one billionth of a meter. Most of the world's advanced semiconductor factories currently make chips with a circuitry width of 90 nanometers.
In a related development, Toshiba, Renesas and Hitachi said they have decided not to pursue their tentative plan to establish an independent chip foundry.
The three companies in January set up a planning company to look into the feasibility of a semiconductor foundry, taking aim at a market dominated by Taiwan Semiconductor Manufacturing Co. and other Taiwanese chipmakers.
The announcement came as little surprise; business daily Nihon Keizai Shimbun said earlier this month that the project was likely to be scrapped due to expectations that such a venture would not make money.