U.S. Philips Corporation

Asm Lithography B.v.

Jan E Van Der Werf

Peter Dirksen

Manfred Gawein Tenner

Willem G Opheij

Marinus Aart Van Den Brink

Cornelis M Van Uijen

Johannes C Rijpers

Henk F Linders

Johannes W Biesterbos

Johannes M Beltman

Philippe J Belien

In an interferometer system, variations of the refractive index in the medium traversed by the measuring beam (123) can be detected by using two measuring beams (123, 125) having wavelengths which differ by a factor of three. For this choice of the wavelength ratio, the interference filters of the polarization elements, such as the beam splitter (127), the .lambda./4 plates (130, 131) and the antireflection coatings can be manufactured relatively easily, and the detection accuracy is increased.

Interferometer system with two wavelengths, and lithographic apparatus

A differential interferometer system for measuring the mutual positions and movements of a first object (WH) and a second object (MH). The system comprises a first interferometer unit (1, 2, 3, 4) having a first measuring reflector (RW) and a second interferometer unit (5, 6, 7, 8) having a second measuring reflector (RM). Since a measuring beam (b.sub.m) passes through both the first and the second interferometer unit and is reflected by both the first and the second measuring reflector, and since the measuring beam and the reference beam (b.sub.r) traverse the same path at least between the two interferometer units, accurate measurements can be preformed very rapidly. The interferometer system may be used to great advantage in a step-and-scan-lithographic projection apparatus.

Differential interferometer system and lithographic step-and-scan

A device is described for aligning a first object provided with a first alignment mark (P) with respect to a second object provided with a second alignment mark (M), which marks have a periodical structure and are imaged onto each other. By selecting beam portions from the radiation from the first alignment mark (P) with the aid of an order diaphragm (55'), which beam portions are deflected through larger angles, the sensitivity of the device to errors can be decreased. Such a device may be used to great advantage in a lithographic apparatus.

Alignment device and lithographic apparatus provided with such a device

A method and apparatus for forming a pattern on a substrate (w), either or not via a mask pattern (c), are described. The radiation dose can be measured accurately and reliably by measuring a latent image of a new, asymmetrical test mark (TM) by means of an optical alignment device present in the apparatus or associated therewith, this latent image being formed by means of production radiation (PB) in the radiation-sensitive layer on the substrate.

Method of determining the radiation dose in a lithographic apparatus

A method and apparatus for repetitively imaging a mask pattern (C) on a substrate (W) are described. The focusing of the projection lens system used for imaging and various other parameters of the apparatus and the projection lens system (PL), as well as illumination doses can be measured accurately and reliably, and measuring devices of the apparatus can be calibrated, by measuring an image of a new asymmetrical test mark formed in the photoresist on the substrate (W) by means of a projection beam (PB).

Method of repetitively imaging a mask pattern on a substrate, and

A method and apparatus for repetitively imaging a mask pattern (C) on a substrate (W) are described. Various parameters of the apparatus and the projection lens system (PL) can be measured accurately and reliably and measuring devices of the apparatus can be calibrated by measuring a latent image of a mark by means of a scanning microscope (LID) forming a diffraction-limited radiation spot (Sp) on the photoresist layer on the substrate (W), in which layer the latent image is formed by means of a projection beam (PB).

A radiation-source unit is described which produces a radiation beam (30) with two components (9, 10) which are polarized perpendicularly relative to one another and which have different frequencies. The unit comprises a radiation source, a beam splitter (4), an acousto-optical modulation system (13, 18) for generating the frequency difference, and a beam combiner (25). Since the beam splitter and the beam combiner are transmission elements and their connecting line extends through the center of the modulation system the unit is compact and no alignment problems occur. Moreover, the frequency difference is adjustable over a wide range.

Radiation-source unit for generating a beam having two directions of

An imaging apparatus has an imaging system (PL) and a focus detection device for determining a deviation between the image plane of the imaging system and a second plane (WS) on which imaging is to take place. The focus error detection system includes a radiation source (S) which supplies a beam (b.sub.f) having a wide wavelength band, an object grating (G.sub.1) and an image grating (G.sub.2) which are imaged onto each other via the second plane. In the focus detection system a reference beam (b.sub.r) which is reflected by the outer surface (RP) of the imaging system can be used in combination or not in combination with the wideband beam and the gratings. By using a number of such focus detection systems a tilt detection device can be realized for detecting the position of the second plane (WS) with respect to the image plane.

Imaging apparatus having a focus-error and/or tilt detection device

A pre-alignment system for use in an apparatus including a fine alignment system. The pre-alignment system includes two optical imaging systems for imaging two alignment marks provided on a substrate for the purpose of fine alignment onto two radiation-sensitive detectors. The outputs signals of the detectors are indicative of the pre-alignments of a associated substrate mark relative to the associated detection systems.

Apparatus for pre-aligning substrate preparatory to fine alignment

An optical imaging arrangement is described which comprises an opto-electronic focussing-error detection system (1, 2, 3, 4, 5, 6, 12, 13, 14, 18, 19, 20, 21) for determining a deviation between the image plane (P.sub.L) of the imaging system (L) and a second plane (P.sub.S) in which the image is to be formed. The image plane (P.sub.F) of the focussing-error detection system is adjustable, for example by means of a pivotable plane-parallel plate (15), so that the zero point of the focussing-error signal (S.sub.f) is adjustable.

Optical imaging arrangement comprising an opto-electronic

An arrangement is described for aligning a mask (1) and a substrate (3) relative to each other by means of grating marks (M.sub.1, M.sub.2 ; P.sub.1, P.sub.2) in the mask and in the substrate. A diaphragm (32) is arranged in the path of the alignment beam (b') behind the mask grating (M.sub.2) and transmits only specific diffraction orders of the gratings (P.sub.2, M.sub.2), so that the alignment signal (S.sub.A) contains less undesired components and becomes more accurate.

Arrangement for aligning a mask and a substrate relative to each other

An apparatus is described for reading a record carrier with an optical radiation-reflecting information structure. The path of the read beam includes a plane-parallel plate, whose surface area is substantially smaller than the cross-sectional area of the read beam, which plate ensures that the beam portion which passes through the plate cannot interfere with the rest of the read beam. After reflection by the record carrier the said beam portion passes through the radiation-deflecting element which deflects the beam portion to two radiation-sensitive detectors. The position of the radiation spot formed by the said beam portion is proportional to the degree of focussing of the read beam on the information structure.

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Eindhoven, Netherlands

Jan E Van Der Werf