Toshiba, NEC, Fujitsu and Renesas have agreed to standardize technology to make 45nm chips.
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 larger rivals such as Intel, Samsung Electronics and Texas Instruments.
Finer circuitry decreases the size of a chip and enables data to be processed faster. It also cuts production costs per chip. But costs for development and production equipment have increased as technology moves to ever-more intricate circuitry, making it difficult for chipmakers to shoulder the burden alone.