The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 11, 1992
Filed:
Jun. 05, 1990
Masao Kosugi, Yokohama, JP;
Akiyoshi Suzuki, Tokyo, JP;
Hideki Ina, Kawasaki, JP;
Hitoshi Fukuda, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A projection exposure apparatus for projecting a pattern formed on a first object such as a reticle upon a second object such as a semiconductor wafer by use of a projection lens system, is disclosed. In the apparatus, a light of a predetermined wavelength is used for the pattern projection, and a light having a different wavelength is used to align the first and second objects by way of the projection lens system. A dichroic mirror film is disposed inclinedly between the first object and the projection lens system so as to reflect one of the light of the predetermined wavelength and the light of the different wavelength, and also to transmit the other. By this dichroic mirror film, the light used for the alignment and reflected back from the second object is extracted out of a light path between the first and second objects. After correcting effects of chromatic aberrations of the projection lens system with respect to the different wavelength, the light for the alignment is passed through the first object. By this, accurate alignment using the light of a wavelength different from that to be used for the pattern projection, is made practically attainable. Also, use of lights of different wavelengths, other than the wavelength to be used for the pattern projection, is made practically attainable. Thus, accurate and stable alignment is attainable regardless of the configuration of the mark provided on the second object.