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US H1,774 HGranted
Projecting exposure apparatus and method of exposing a circuit substrate
OwnerTakashi Miyachiinventor
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OwnerTakashi Miyachiinventor
Estimating the term…
A scanning projection exposure apparatus having a projection optical system (11), for serially transferring a pattern on a reticle (7) onto a wafer (12). The exposure apparatus control the position and/or the tilt angle of the wafer (12) such that the surface of the wafer (12) may be continuously adjusted during the scanning exposure operation so as to be coincident with an image plane of the projection optical system (11), with a high tracking accuracy, even when the image plane of the projection optical system (11) tends to vary during the scanning exposure operation. An image of that portion of the pattern on the reticle (7) which is confined in an illumination area (8) is formed in a plane through the projection optical system. This plane is used as a first reference plane (62). Parameters of the first reference plane (62) such as the tilt angle .theta..sub.p are determined by measurement. An image plane is defined by conjugate images (formed on the wafer side) of the points passing the center of the illumination area (8) when the reticle (7) is moved for scanning in the X-direction. This image plane is used as a second reference plane (65). The tilt angle .THETA..sub.x of the second reference plane (65) is determined by measurement. When the scanning exposure operation is performed, the tilt angle of the illumination field (13) of the wafer (12) is made coincident with that of the first reference plane (62), and the focusing position of the wafer (12) is made coincident with that of the second reference plane (65).
A projection exposure apparatus having a projection optical system with an optical axis, in which a mask and a photosensitized substrate are moved for scanning in synchronism with each other and relative to said projection optical system while an image of a portion of a pattern on said mask is projected through said projection optical system onto a predetermined exposure area on said substrate, said projection exposure apparatus comprising:
A projection exposure apparatus having a projection optical system with an optical axis, in which a mask and a photosensitized substrate are moved for scanning in synchronism with each other and relative to said projection optical system while an image of a portion of a pattern on said mask is projected through said projection optical system onto a predetermined exposure area on said substrate, said projection exposure apparatus comprising:
A method of exposing a circuit substrate by using a projection optical system with an optical axis, in which a mask and a photosensitized substrate are moved for scanning in synchronism with each other and relative to said projection optical system while an image of a portion of a pattern on said mask is projected through said projection optical system onto a predetermined exposure area on said substrate, said method comprising the steps of:
A method of exposing a circuit substrate by using a projection optical system with an optical axis, in which a mask and a photosensitized substrate are moved for scanning in synchronism with each other and relative to said projection optical system while an image of a portion of a pattern on said mask is projected through said projection optical system onto a predetermined exposure area on said substrate, said method comprising the steps of:
An exposure apparatus including a projection optical system with an optical axis for projecting a pattern on a mask onto a photosensitized substrate and a substrate stage for moving said substrate on the image side of said projection optical system, said exposure apparatus comprising:
A scanning exposure apparatus for serially transferring an image of a pattern on a mask onto a photosensitized substrate, comprising:
A method of exposing a circuit substrate by using a projection optical system with an optical axis, in which an image of a portion of a pattern on a mask is projected through said projection optical system onto a predetermined exposure area on a photosensitized substrate, said method comprising the steps of:
A method of exposing a circuit substrate by using a projection optical system with an optical axis, in which a mask having a pattern formed thereon is illuminated so that an image of a portion of said pattern on said mask is projected through said projection optical system onto a predetermined exposure area on a photosensitized substrate, said method comprising the steps of:
Dependencies are inferred from the claim text.
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1. Field of the Invention
The present invention relates to a projection exposure apparatus for use in photolithographic processes or fabricating semiconductor devices (such as LSIs), imaging devices (such as CCDs), liquid crystal displays (LCDs), thin film magnetic heads and others. More particularly, the present invention relates to a scanning exposure type of projection exposure apparatus, such as of a so-called step-and-scan type, in which a mask and a photosensitized substrate are moved for scanning in synchronism with each other and relative to an exposure optical system, so as to serially transfer a pattern formed on the mask onto the photosensitized substrate.
2. Description of the Related Art
The above and other objects, features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments thereof, reference being made to the accompanying drawings, in which:
FIG. 1 is a schematic representation showing a projection exposure apparatus of a step-and-scan type to which one embodiment of the present invention is applied;
FIG. 2 is a plan view of the wafer 12 of FIG. 1 showing distribution of measurement points for measuring the focusing positions on the wafer 12;
Referring now to the accompanying drawings, a preferred embodiment of the projection exposure apparatus in accordance with the present invention will be described in detail. This embodiment shows an exemplified application of the present invention to a step-and-scan type of projection exposure apparatus.
FIG. 1 shows the projection exposure apparatus, in which a light source system 1 comprising a light source and an optical integrator emits an illumination beam IL for exposure. The illumination beam IL passes through a first relay lens 2, a reticle blind (variable field stop) 3, a second relay lens 4, is reflected by a mirror 5, passes through a main condenser lens 6, and illuminates that portion of a pattern bearing surface (bottom surface) of a reticle 7 which is then confined in a slit-like illumination area 8 with a uniform illumination distribution. The reticle blind 3 is positioned in a plane substantially conjugate to the plane of the pattern bearing surface of the reticle 7, so that the position and the geometry of the aperture of the reticle blind 3 determine the position and the geometry of the illumination area 8.
An image of that portion of the pattern on the reticle 7 which is confined in the illumination area 8, which is formed through a projection optical system 11, is projected for exposure onto a photoresist-coated wafer 12 and within a slit-like illumination field 13 on the wafer 12. For specifying positions and directions in the disclosed arrangement, we use here a three-dimensional rectangular coordinate system with the X-, Y- and Z-axes, in which the Z-axis extends parallel to the optical axis of the projection optical system 11, the X-axis extends perpendicular to the optical axis and parallel to the sheet surface of FIG. 1 and the Y-axis extends perpendicular to the sheet surface of FIG. 1. The reticle 7 is held on a reticle stage 9 which, in turn, is supported on a reticle base 10 for translational movement in the x-direction, or the scanning direction, by means of a drive unit such as a linear motor (not shown). A moving mirror 18 is fixedly mounted on the reticle stage 9 for movement with the latter. A laser interferometer 19 is fixedly mounted on a stationary member outside the reticle stage 9. The moving mirror 18 and the laser interferometer 19 are used to measure the X-coordinate of the reticle 7. The measured X-coordinate of the reticle 7 is supplied to a main control system 20 which serves to generally control various operations in the entire projection exposure apparatus. The main control system 20 controls the position and the velocity of the reticle 7 through the reticle stage drive system 21 and the reticle stage 9.