Motorola Corporation

Infineon Technologies Ag

Günter Hraschan

Sebastian Schmidt

Thorsten Schedel

Leroy Grant

By a unit for determining fractions of a substance in a gas or gas mixture, measurements are carried out on the gas or gas mixture for purging a lens in a projection apparatus for projecting patterns onto a substrate. The results of a first measurement on the gas fed to the lens are compared with the results of a measurement of the gas removed from the lens. If, the substance is a contaminating substance that leads to a deposit on the lens under the influence of high-energy radiation from an illumination source, the difference is used to infer photochemical reactions on the surface of the lens that lead disadvantageously to the deposition. A signal is generated as a consequence of the comparison and is used to take preventive measures against a degradation of the lens. Mass spectrometers, electric or optical sensors and other known methods for substance analysis are used as measurement units.

Method for purging an optical lens

In a single cleanroom ( ) for first ( ) and second ( ) wafer processing machines, an exhaust device ( ) surrounds the second machine ( ) that temporarily produces exhaust gas ( ) which is detrimental to the processes in the first machine ( ). Additionally to a first directed air flow ( ) available in the cleanroom ( ), the exhaust device ( ) generates&mdash;in the proximity of gas leakage openings of the second machine ( )&mdash;a second air flow ( ) that prevents the exhaust gas ( ) from further being moved by the first air flow ( ) to the first machine ( ).

Growing community of inventors

Dresden, Germany

Günter Hraschan