General E-Beam Deflection Correction Technique
Original Publication Date: 1979-Jan-01
Included in the Prior Art Database: 2005-Feb-19
A scanning beam of charged particles is utilized as a tool for fabricating semiconductor devices. Such a system must include a deflection system capable of producing high resolution patterns over large fields (5 mm) and with positional overlay accuracy better than 50 PPM. These requirements are difficult to achieve because of inherent distortions and errors in converting deflection signals into beam position. One way of compensating for such deflection distortion errors is by measuring the deflection over a master target of known characteristics. Measured data are correlated to ideal deflection data, then used to generate correction terms corresponding to the differences. This technique provides a method and apparatus for measuring the beam deflection positional errors and correcting them.