Superconducting bending magnets for compact synchrotron radiation source
A 180 degrees superconducting magnet has been constructed for a synchrotron radiation source. The authors describe the superconducting magnet design and some component test results for the compact synchrotron radiation source. The magnetic field at the electron orbit is 4.5 T. The bending radius is 0.593 m. The magnet has several features such as low liquid helium consumption ratio, persistent current operation, high homogeneous magnetic fields, and leakage flux shielding by the iron core surrounding the cryostat. Component tests of persistent current switches of 15 Omega and 3 Omega and a superconducting joint test have been performed.<<ETX>>
The Coil Protection and the Long Term Operation of the Compact SR Superconducting Magnet
The Coil Protection and the Long Term Operation of the Compact SR Superconducting Magnet Tetsuya Matsuda,Member,Masao Morita,Member, Syunji Yamamoto,Member,Toshie Takeuchi,Member, Takeo Kawaguchi,Non Member,Shiro Nakamura Member, Tadatoshi Yamada,Member(Mitsubishi Electric Corporation) Masatami Iwamoto,Member(Kagawa University) We developed a compact SR magnet which is operated at 3.5T(350A) at persistent current mode. This SR magnet is used for the light source of X ray lithography. If the SR magnet is located at the semiconductor factory, the magnet needs to be highly reliable for a long term persistential operation. The coil should be protected from a large terminal voltage due to its high inductance in case of quenching even if it is a rare accident. We evaluate the coil voltage and developed an active coil protection system for long term persistent operation. This system is composed of the quench detector, external resistive heaters and current power supplies for those heaters. Each components are connected to UPS(uninterruptive power supply) that can supply power for 15 hours with batteries. We can lower the maximum quench voltage to the sufficient safety level that is about 1,000V by using this active coil protection system. We have obtained total 40,000hours of operational experiences of this superconducting magnet at persistent current mode without any trouble. At present, this magnet is under successive operation for nearly one year. Through these operations, we have confirmed the high reliability of this superconducting magnet.
The future costs of semiconductor lithography
A method for comparing the costs for photoprocessing high volume semiconductor logic and memory wafers is presented. Industry lithographic trends and process structures are discussed and a cost model is applied. Some typical results obtained with optical tooling and x‐ray synchrotron based lithography are discussed for 1/2 μ ground rules. The model consists of two sections; exposure costs and process costs per level. Both areas are addressed and discussed. Equivalent yield has been assumed for all processes. Normalized results done with the model are presented and discussed. Net conclusions are that photo process costs are as great or greater than the exposure costs, and that x‐ray technology with a synchrotron source becomes competitive with optical technologies for large volume applications because of process simplicity. Optical technologies will continue to be used by many manufacturers because of their lower initial investment and evolutionary nature.