Shin-Etsu Chemical has succeeded in developing a large-size magnetic circuit which will be the world's largest-class permanent magnet-type magnetic circuit. Its total weight is about 10 tons, and it will be used mainly in manufacturing-process applications, such as for the making of next-generation MRAM semiconductors and MR (Magneto Resistive) sensors.

For the manufacturing of MRAMs, heat treatment in a magnetic field is essential, and in that process, generation of a very large magnetic field of more than 1 tesla is required. So far, electromagnets and superconducting magnets have been used for this purpose. However, recently many semiconductor manufacturers are adopting permanent magnet-type magnetic circuits because of their good magnetic-field performance and magnetic-field stability, as well as the fact that these permanent magnet-type magnetic circuits have the advantage of being power-saving and maintenance-free. At the same time, with the trend in recent years toward larger-diameter silicon wafers, the need for these types of larger magnetic circuits has been increasing.

Shin-Etsu Chemical has been manufacturing various large-size magnetic circuits using its rare earth magnets. With its total weight of about 10 tons, cylindrical shape of 1.4-meter diameter and height of 1-meter, the new type of magnetic circuit that Shin-Etsu has now developed is the world's largest-class permanent magnet-type magnetic circuit that generates a strong magnetic field. This magnetic circuit is being introduced ahead of other companies worldwide for application in the processing of 300mm wafers.