Compensated magnetic deflection coil for electron beam lithography system
US4251728A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 1979 |
| Grant date | Feb 17, 1981 |
| Priority date | — |
| Expiry date | Jul 30, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/1475
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A toroidal magnetic deflection coil for an electron beam lithography system which is compensated for deflection placement errors that normally result from eddy currents generated within the coil windings by deflection current inputs to the coil. The compensation is achieved through addition of passive conductive material along the outer periphery of the coil. The conductive material or layer is arranged close to the outer arms of the toroidal coil windings, and thereby compensates the eddy currents within the deflection coils generated by the deflection currents in the inner arms. The compensating material can be utilized to compensate for beam drag which results from the driving circuit settling time and the inductive or capacitive coupling as well, by adding more material of appropriate dimensions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.