JP2005353966A - Scanning aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a measurement of illuminance unevenness at optional timing except exposing time. <P>SOLUTION: A scanning aligner comprises a projecting optical system projecting a pattern on an original plate to substrate top surface, an illuminating optical system illuminating the original plate by converting a light from a light source into a flux of light of designated illumination distribution, and a scanning means for transferring the original plate and the substrate in single dimension by synchronizing them with respect to the above-mentioned projecting optical system. In a scanning type projecting optical device exposing the pattern on original plate surface to the substrate with a scanning exposing system, the device has an illumination measuring system for measuring an illuminance of the above-mentioned flux, and a transferring means for transferring at least one portion of the illumination measuring system inside the above-mentioned flux in the above-mentioned illuminating optical system or the above-mentioned projecting optical system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a scanning projection exposure apparatus used when manufacturing a semiconductor element such as an IC or LSI, a liquid crystal display element, a thin film magnetic head or the like in a photolithography process.

  When manufacturing semiconductor elements, liquid crystal display elements, and thin-film magnetic heads, a pattern formed on an original plate called a mask or a reticle (hereinafter referred to as an original plate) using a lithography technique, a photosensitive material called a resist is made of silicon. A projection exposure apparatus that performs projection exposure on a substrate (hereinafter referred to as a substrate) coated on the surface of a wafer or a glass substrate is used.

  Conventionally, in a projection exposure apparatus, a proximity exposure system that performs batch exposure by bringing an original and a substrate into close contact with each other, or a mirror that illuminates an original with circular illumination light and scans and exposes the substrate through a reflective optical system. Projection exposure method or step-and-repeat reduction projection type exposure apparatus (so-called stepper) that performs batch exposure of a reduced exposure image of an original while moving each exposure region on the substrate sequentially to the exposure region of the projection optical system. Has been used.

  In a step-and-repeat exposure apparatus that is a batch exposure method, when the projection optical system is constituted by a lens, an effective imaging region is circular, but a semiconductor integrated circuit is generally rectangular. Therefore, the original plate to be used has a rectangular shape as a matter of course, and if it is intended to secure the maximum transfer area in the case of batch exposure, a rectangular area inscribed in the circular imaging area of the projection optical system. Thus, even the largest transfer region is a square with sides of 1 / √2 of the diameter of the circle.

  On the other hand, the transfer area is expanded by scanning and moving the original and the substrate in synchronization with each other using a rectangular exposure area having a diameter approximately equal to the diameter of the circular imaging area of the projection optical system. A so-called slit scan exposure method or a step-and-scan method (hereinafter referred to as a slit scan method) has been proposed.

  The slit scanning type projection exposure apparatus is described in detail in, for example, pages 96 to 99 of the February 1993 issue of Oplus E. The exposure apparatus has a rectangular exposure area, and the slit is provided for each shot. The scanning exposure is performed by scanning, and when the scanning exposure of one shot is completed, the substrate steps to the next shot, and the scanning exposure of the next shot is repeated in the same manner. The exposure process of completing the exposure of the entire wafer is performed by repeating the scan for this.

  In such a slit scanning method, when a projection optical system having an imaging region of the same size is used, the slit scanning method is larger than a step-and-repeat method that performs batch exposure for each transfer region using a projection lens. A transfer area can be secured. In other words, since there is no restriction by the optical system in the scanning direction, it is possible to ensure only the stroke of the scanning stage, and it is possible to ensure a transfer area approximately √2 times in the direction perpendicular to the scanning direction. .

An exposure apparatus for manufacturing a semiconductor integrated circuit is required to expand a transfer region and improve resolution in order to cope with manufacture of a highly integrated chip. From the viewpoint of performance, it is advantageous in terms of cost, and the exposure method of the slit scan method is attracting attention as a mainstream of future exposure apparatuses.
In such a slit scanning method, it is required that the exposure amount obtained by integrating the slit width in the scanning direction is uniform in the direction orthogonal to the scanning direction.

  For this reason, a member called a slit for forming the slit width has a function of adjusting the slit width in the scanning direction.

Further, in order to measure the integrated exposure amount in the width direction of the slit, as shown in FIG. 3, an illuminance unevenness measuring device is disposed on the stage holding the substrate, and the stage is used when measuring the illuminance unevenness. Is driven in a direction orthogonal to the scanning direction to measure illuminance unevenness, and based on the result, the width of the slit is adjusted so that the exposure amount becomes uniform.
Japanese Patent Laid-Open No. 5-47638 JP-A-7-142306

  However, in such a conventional method, the illuminance unevenness measuring device is arranged on the substrate stage on which the substrate is mounted. Therefore, when measuring the illuminance unevenness, the exposure processing of the apparatus has to be interrupted. Since this reduces the processing efficiency of the apparatus, the measurement is actually performed once a day or when an abnormality occurs. In addition, since the measurement interval is free as described above, there is a problem that even if an abnormality occurs during that time, discovery is delayed and a large number of defects are generated during that time.

  In view of the above problems, an object of the first invention according to the present invention is to enable measurement of exposure unevenness at any timing other than during exposure.

  The present invention provides a projection optical system for projecting a pattern on an original onto a substrate, an illumination optical system for illuminating the original by converting light from a light source into a light beam having a desired illuminance distribution, and the projection optical system for the original and the substrate. And an illuminance measurement system for measuring the illuminance of the light beam in a scanning projection exposure apparatus that exposes a pattern on an original surface onto a substrate by a scanning exposure method. And a moving means for moving at least a part of the illuminance measurement system in the light beam in the illumination optical system or the projection optical system.

  According to the present invention, the illuminance unevenness can be measured at any timing other than the exposure time regardless of the state of the substrate stage, and the illuminance unevenness can be adjusted without deteriorating the operation efficiency of the apparatus. This also has the effect of preventing the occurrence of poorly exposed substrates due to uneven illuminance.

(First embodiment)
FIG. 1 is a diagram that best represents the features of the present invention. The light generated by the lamp 1 is reflected and collected by the elliptical mirror 2, and the light reflected and collected by the elliptical mirror 2 is bent 90 ° by the reflecting mirror 3, and is shaped into a uniform rectangular shape by the optical system 4. The reflection mirror 5 bends the light in the original direction, cuts out the light shaped in a rectangular shape with a slit 6 having an arc shape and a substantially constant width in the scanning direction, and the adjustment mechanism 7 adjusts the opening width of the slit 6. The optical system 8 illuminates the original 9 with a predetermined magnification of the cut light. The projection optical system 10 projects the pattern of the original 9 illuminated in a slit shape onto the substrate 11. The substrate stage 12 holds and moves the substrate.

  A fine circuit pattern is drawn on the original 9, and this pattern is transferred onto the substrate via the projection optical system 10 by synchronously scanning the original 9 and the substrate 11 with a scanning mechanism (not shown).

  The mirror 15 is retracted to a position that does not block exposure light by a moving mechanism (not shown) except during measurement. In the case of performing illuminance unevenness measurement, the moving mechanism is driven to move the mirror 15 into the exposure light beam and guide the exposure light to the illuminometer 16. The mirror 15 is moved in the exposure light beam cross section by the arm 17 and the drive motor 18. Further, since the illuminance meter 16 is arranged at a position equivalent to the focal plane of the substrate 11, it is possible to effectively measure the illuminance unevenness of the exposure light irradiated onto the substrate. It is possible to automatically adjust the illuminance unevenness by giving a command to the adjustment mechanism 7 through the calculator and the drive command circuit with the information on the illuminance unevenness measured by the illuminometer 14.

  With this configuration, illuminance unevenness measurement can be measured and adjusted at any time other than the exposure process regardless of the state of the substrate stage 12, and an irregularity in illuminance should occur. Even in such a case, the correction can be performed immediately without degrading the processing efficiency of the substrate, and the occurrence of substrate defects can be suppressed.

  In addition, the uneven illuminance measuring instrument 13 embedded in the stage, which is configured in the conventional example in the present invention, may remain for calibration during maintenance.

(Second embodiment)
FIG. 2 is a diagram showing a second embodiment according to the present invention. The illumination optical system 20 illuminates the original plate 9 with exposure light having an arc shape and a uniform light amount. The illuminometer 26 is disposed immediately below the slit in the illumination optical system 20. The motor 18A drives the arm 27 to move the illuminance unevenness measuring device 26 in an arc shape.

  In the above configuration, the illuminance unevenness measuring device 26 is normally retracted to a position other than the opening of the arc-shaped slit, so that exposure is not hindered. When measuring the illuminance unevenness, the illuminance unevenness measuring device 26 is guided within the effective range of the slit 6 by the drive motor 18A connected to the arm 27, and scans the exposure light in an arc shape to measure the illuminance unevenness. . It is possible to automatically adjust the illuminance unevenness by giving a command to the adjusting mechanism 7 through the calculator and the drive command circuit with the information on the measured illuminance unevenness.

The figure which shows a 1st Example. The figure which shows a 2nd Example. The figure explaining a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lamp 2 Elliptical mirror 3 Bending mirror 4 Shaping optical system 5 Reflection mirror 6 Slit 7 Slit width adjustment mechanism 8 Projection optical system 9 Original 10 Projection optical system 11 Substrate 12 Substrate stage 13, 16, 26 Illuminance meter 14 Illuminance meter 15 Reflection mirror 17, 27 Arm 18, 18A Drive motor 20 Illumination optical system

Claims (1)

  The projection optical system that projects the pattern on the original onto the substrate, the illumination optical system that illuminates the original by converting the light from the light source into a luminous flux with a desired illuminance distribution, and the original and the substrate are synchronized with the projection optical system An illuminance measuring system for measuring the illuminance of the luminous flux, and a illuminance measuring system for measuring the illuminance of the luminous flux in a scanning projection exposure apparatus that exposes a pattern on the original plate onto the substrate by a scanning exposure method. A scanning projection exposure apparatus comprising: a moving means for moving at least a part of a measurement system within the light beam in the illumination optical system or the projection optical system.

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