Carl-zeiss-stiftung

Carl Zeiss Smt Gmbh

Carl-zeiss-smt Ag

Andreas Dorsel

Gerhard Hohberg

Uwe Vry

Stefan Wolfgang Schmidt

Wilfried Walch

Toralf Gruner

Alexander Epple

Norbert Wabra

Susanne Beder

Bernhard Kneer

Peter Greve

Michael Kuchel

Martin Blumentritt

Klaus Freischlad

Berthold Schierle

Stefan Schmidt

A method for examining at least one wafer () with regard to a contamination limit, in which the contamination potential of the resist () of the wafer (), which resist () outgasses contaminating substances, is examined with regard to a contamination limit before the wafer () is exposed in an EUV projection exposure system (). The method preferably includes: arranging the wafer () and/or a test disc coated with the same resist () as the resist () of the wafer () in a vacuum chamber (), evacuating the vacuum chamber (), and measuring the contamination potential of the contaminating substances outgassed from the wafer () in the evacuated vacuum chamber (), and also comparing the contamination potential of the wafer () with a contamination limit. An EUV projection exposure system () for carrying out the method is also disclosed. By heating wafers having a high contamination risk, the contamination of optical elements in the projection exposure system () on wafer exposure may be distinctly reduced.

Method for examining a wafer with regard to a contamination limit and EUV projection exposure system

A method for examining at least one wafer () with regard to a contamination limit, in which the contamination potential of the resist () of the wafer (), which resist () outgasses contaminating substances, is examined with regard to a contamination limit before the wafer () is exposed in an EUV projection exposure system (). The method preferably includes: arranging the wafer () and/or a test disc coated with the same resist () as the resist () of the wafer () in a vacuum chamber (), evacuating the vacuum chamber (), and measuring the contamination potential of the contaminating substances outgassed from the wafer () in the evacuated vacuum chamber (), and also comparing the contamination potential of the wafer () with a contamination limit. An EUV projection exposure system () for carrying out the method is also disclosed. By rejecting wafers having an especially high contamination risk, the contamination of optical elements in the projection exposure system () on wafer exposure may be distinctly reduced.

Imaging system of a microlithographic projection exposure apparatus, with a projection objective () that serves to project an image of a mask which can be set into position in an object plane onto a light-sensitive coating layer which can be set into position in an image plane, and with a liquid-delivery device () serving to fill immersion liquid () into an interstitial space between the image plane and a last optical element () on the image-plane side of the projection objective; wherein the last optical element on the image-plane side of the projection objective is arranged so that, seen in the direction of gravity, it follows the image plane; and wherein the projection objective is configured in such a way that when the system is operating with immersion, the immersion liquid has at least in some areas a convex-curved surface facing in the direction away from the image plane. It is also proposed for the last optical element () on the image-plane side of the projection objective to be arranged below the image plane in such a way that the immersion liquid () is held at least in part in a substantially tub-shaped area on the last optical element on the image-plane side. Also, a rotator can be provided which serves to rotate a substrate carrying the light-sensitive coating () between a transport orientation in which the light-sensitive coating lies on a substrate surface that faces against the direction of gravity and an exposure orientation in which the light-sensitive coating () lies on a substrate surface that faces in the direction of gravity.

Imaging system for a microlithographical projection light system

The invention is directed to an arrangement for operating a laser diode. A two-stage stabilization circuit is provided for stabilizing the wavelength of a laser diode to exactly defined values for its use in distance measuring interferometers. In addition to presetting the operating parameters of current and temperature of the laser diode, the emitted wavelength of the laser diode is controlled to a predetermined transmission maximum of a Fabry-Perot interferometer. At switch-on, a control program can be called up and compute new values for the operating parameters premised on the last measured values of the operating parameters and initially determined and stored coefficients. In this way, the program always reliably sets the wavelength of the laser diode to the same transmission maximum.

Arrangement for operating a laser diode

A transmitting and receiving arrangement for fiber-optic sensors includes a first radiation source L1 having radiation which is conducted via an optical switch having a wavelength-dependent transmission or reflection filter into the fiber FA going to the sensor head. The radiation returning from the fiber is conducted via the optical switch to a first detector D1. The arrangement further includes: a second detector D2 which is permanently optically coupled into the radiation path of the first radiation source L1; and, a second radiation source L2, which is switched on alternately to the first radiation source L1 and both detectors D1, D2 are subjected to the radiation of this radiation source.

Radiating and receiving arrangement for a fiber-optic sensor having dual

The invention is directed to an optical switch for a sensor. The optical switch conducts radiation emitted from a radiation source into a fiber leading to the sensor and conducts radiation returning from this fiber onto an optoelectric receiver. The optical switch includes a filter having wavelength-dependent transmission and reflection characteristics as well as optical components for collimating or focusing. The optical components together with the filter define a component unit in the form of an acute angle optical switch. The optical switch also has a first beam splitter mounted downstream of the component for collimating the radiation emitted by the radiation source. The beam splitter splits off a component of the radiation emitted by the radiation source as a reference beam and the reference beam is guided via deflecting prisms and spacers to a second beam splitter. The second beam splitter geometrically superposes the reference beam onto the measurement beam returning from the fiber via the optical switch. An air gap is provided ahead of the second beam splitter for accommodating a movable diaphragm therein which alternately interrupts the measurement beam or the reference beam.

Optical switch

The injection current for a laser diode is modulated so that a pregiven coherence function is obtained which drops off continuously at both ends outside of the coherence length. Several laser diodes are used for a very short coherence length for which the modulated wave numbers of the emitted radiation follow one another or overlap.

Growing community of inventors

Aalen, Germany

Andreas Dorsel