JPH0729788A - Projection aligner - Google Patents

Abstract

PURPOSE:To obtain the best resolving power and focal depth for each reticle pattern when a deformation illumination aperture is changed in a projection aligner by eliminating the generation of particles in an optical system and by the designation using a recipe. CONSTITUTION:The illumination light 4 outputted from an ultraviolet ray light- emitting lamp 1 is condensed and reflected by an oval reflecting mirror 2 and a plane reflecting mirror 3, and after passing through a fly-eye lens 6, the light passes through a deformation illumination aperture 13 for change of intensity and shape of the light flux optimum to reticle pattern, reflected by a plane reflecting mirror 7, condensed by a condenser lens 8, passes through a projection lens 10, and the reticle pattern is projected to the material to be treated. A deformation illumination liquid crystal aperture 13, in which the principle of liquid crystal shutter is used, is used as the deformation aperture, and the size and the shape of the light flux of the illumination light 4 is changed by controlling the liquid crystal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type exposure machine for projecting an exposure pattern onto a semiconductor substrate or the like, and more particularly to a projection type exposure machine having a modified illumination aperture.

[0002]

2. Description of the Related Art As shown in the configuration diagram of FIG. 7, a conventional projection type exposure apparatus includes an ultraviolet light emitting lamp for outputting illumination light 4, an elliptical reflecting mirror 2 for converging the illumination light 4, and A plane reflecting mirror 3 for bending the optical path of the illumination light 4 by 90 °, and an input lens 5 for making the illumination light 4 parallel to its optical axis.
And a fly-eye lens 6 for reducing the coherence of the illumination light 4, and the illumination light 4 that has passed through the fly-eye lens 6.
Plane reflecting mirror 7 for bending the optical path of
Condenser lens 8 for condensing light, a reticle 9 for defining an exposure pattern, a projection lens 10 for projecting this exposure pattern on an object 11 to be processed, and a fly-eye lens 6 at the rear stage. And a modified illumination aperture 12 for changing the luminous flux and the shape of the illumination light 4 that has passed through.

Next, the operation of this exposure apparatus will be described.
The illumination light 4 output from the ultraviolet light emitting lamp 1 is condensed by the elliptical reflected light 2, bent by 90 ° by the plane reflection mirror 3, becomes parallel to the optical axis by the input lens 5, and enters the fly-eye lens 6. . The illumination light 4 that has passed through the fly-eye lens 6 is changed in the size and shape of the light flux by the modified illumination aperture 12, bent by 90 ° by the elliptical reflecting mirror 7, and then condensed by the condenser lens 8, and then the reticle. 9. The reticle pattern was projected onto the object to be processed 11 after passing through the projection lens 10.

[0004]

In this conventional projection type exposure apparatus, since exposure is carried out using a fixed dedicated aperture as the modified illumination aperture, the optimum modified illumination aperture is selected for each reticle pattern. It was impossible. There is also a projection type exposure machine that has a function of automatically changing a plurality of apertures for modified illumination of a predetermined shape and automatically changing them according to the reticle pattern.However, in a normal mass production factory, there are several hundred types of reticles. It is difficult in terms of space and cost to prepare all of the modified illumination apertures that match the reticle pattern. Therefore, it is difficult to obtain the best resolution and depth of focus for each reticle pattern.

Further, as shown in Japanese Utility Model Laid-Open No. 61-151 and Japanese Patent Laid-Open No. 183818/1989, there is also a projection type exposure machine having a modified illumination aperture capable of mechanically changing the shape. However, there is a problem in that when mechanically changing the shape, particles may be generated in the optical system to cause a product defect.

[0006]

SUMMARY OF THE INVENTION A projection type exposure apparatus of the present invention includes an illumination optical system for outputting illumination light, a fly eye for reducing coherence of illumination light, and an exposure pattern for defining an exposure pattern. In a projection type exposure machine having an exposure mask and a projection optical system for projecting the exposure pattern onto an object to be processed, the size and shape of the luminous flux of the illumination light passing through the fly eye near the fly eye are determined. It is equipped with an optically controlled aperture for modified illumination.

[0007]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a projection type exposure apparatus according to an embodiment of the present invention. As shown in FIG. 1, an ultraviolet light emitting lamp 1 for outputting the illumination light 4, an elliptical reflecting mirror 2 for converging the illumination light 4, and a flat reflecting mirror for bending the optical path of the illumination light 4 by 90 °. 3, an input lens 5 for making the illumination light 4 parallel to its optical axis, a fly-eye lens 6 for reducing the coherence of the illumination light 4, and an optical path of the illumination light 4 passing through the fly-eye lens 6. A flat reflecting mirror 7 for bending 90 °, and a condenser lens 8 for collecting the illumination light 4
A reticle 9 for defining an exposure pattern, and a projection lens 10 for projecting the exposure pattern on an object 11 to be processed.
And a modified illumination liquid crystal aperture 13 for changing the size and shape of the luminous flux of the illumination light 4 that has passed through the fly's eye lens 6 and a cooling illumination liquid crystal aperture 13. Chiller 14,
A liquid crystal controller 15 for controlling the modified illumination liquid crystal aperture 13 and a main controller 16 for controlling the liquid crystal controller 15 are provided.

Next, the operation will be described. In FIG. 1, the illumination light 4 output from the ultraviolet light emitting lamp 1 is condensed by the elliptical reflecting mirror 2 and bent by 90 ° by the plane reflecting mirror 3, and then becomes parallel to the optical axis by the input lens 5 to fly eye. Enter the lens 6. The illumination light 4 that has passed through the fly-eye lens 6 passes through the modified illumination liquid crystal aperture 13 for changing the size and shape of the light flux that is optimum for the reticle pattern, and after being bent 90 ° by the elliptical reflecting mirror 7,
The light is condensed by the condenser lens 8, passes through the reticle 9 and the projection lens 10, and projects the reticle pattern onto the object 11.

FIG. 2 is a diagram showing the construction of the main part of this embodiment.
9A and 9B are shape diagrams of the fly-eye lens 6 and the modified illumination liquid crystal aperture 13, respectively. FIG. 3 is a diagram showing the positional relationship between the fly-eye lens 6 and the modified illumination liquid crystal aperture 13 of this embodiment. 4, 5 and 6 are shape diagrams showing an operation example of the modified illumination liquid crystal aperture 13 of the present embodiment.

As shown in FIGS. 2 (a) and 2 (b), the modified illumination liquid crystal aperture 13 has a circular liquid crystal panel structure, and each liquid crystal 17 corresponds to one fly eye 18 of the fly eye lens 6. Has a shape corresponding to 1 to 5, 1
The size is 0 mm square. Further, as shown in FIG. 3, the illumination light 4 made parallel to the optical axis by the input lens 5 is expanded by the fly-eye lens 6 as shown by the dotted line. Modified Illumination Liquid Crystal Aperture 13 of this Embodiment
Is installed on the fly eye 18 side in front of the position where the illumination light 4 output from each fly eye 18 intersects with each other so that the illumination light 4 output from each fly eye 18 can be individually blocked.

The main controller 16 also stores the shape data of the modified illumination aperture that can obtain the best resolution and depth of focus for each reticle pattern. When the recipe is designated to the main controller 16, the main controller 16 sends the shape data to the liquid crystal controller 15, and the liquid crystal controller 15 causes the individual liquid crystal 1 of the liquid crystal aperture 13 for the modified illumination.
7 is controlled to pass or block the illumination light 4.

By the above operation, it is possible to form an annular illumination aperture as shown in FIG. 4, a four-hole illumination aperture as shown in FIG. 5, and all other conceivable patterns. At this time, if each of the liquid crystals 17 is further subdivided, the ring zone portion can be made closer to an arc shape. The liquid crystal control operation of the present embodiment described above is performed using the principle of the liquid crystal shutter.

Further, by controlling the transmittance of the liquid crystal 17 by the liquid crystal controller 15, the liquid crystal aperture 13 for modified illumination having a desired neutral density filter (ND filter) can be realized. As shown in FIG. 6, an annular illumination aperture in which an ND filter having a transmittance of 50% is provided in the illumination light output portion from the fly-eye lens near the center is also easily possible. In addition, it is possible to individually specify an arbitrary transmittance for each fly eye 18 after forming apertures for modified illumination of all possible patterns.

In the present embodiment, by using the modified illumination liquid crystal aperture 13 as the modified illumination aperture, the main controller 16 designates the modified illumination aperture most suitable for each reticle pattern in the recipe at the time of exposure. It becomes possible to do. Moreover, since the deformation illumination aperture is not mechanically replaced and the principle of the liquid crystal shutter is used, no dust is generated. Further, with respect to the heat generation of the modified illumination liquid crystal aperture 13 due to the irradiation of the illumination light 4, a structure in which a coolant is circulated by a chiller 14 to radiate heat is adopted.

[0015]

As described above, according to the present invention, the shape data of the modified illumination aperture corresponding to all the reticles is held in the main controller, and the liquid crystal of the modified illumination liquid crystal aperture is controlled to the shape according to the data. There is an effect that the best resolution and depth of focus can be obtained for each reticle pattern only by designating the recipe. Further, since the shape of the modified illumination aperture is formed by using the principle of the liquid crystal shutter, there is an effect that there is no possibility of a product defect due to dust generation due to the modification of the modified illumination aperture.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a projection type exposure apparatus according to an embodiment of the present invention.

2A and 2B are diagrams showing a configuration of a main part in one embodiment of the present invention, wherein FIG. 2A is a shape diagram of a fly-eye lens, and FIG. 2B is a shape diagram of a modified illumination liquid crystal aperture.

FIG. 3 is a positional relationship diagram of a fly-eye lens and a modified illumination liquid crystal aperture according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of an operation example 1 of the liquid crystal aperture for modified illumination in the embodiment of the present invention.

FIG. 5 is an explanatory diagram of an operation example 2 of the modified illumination liquid crystal aperture according to the embodiment of the invention.

FIG. 6 is an explanatory diagram of an operation example 3 of the liquid crystal aperture for modified illumination in the embodiment of the present invention.

FIG. 7 is a configuration diagram of a conventional projection type exposure apparatus.

[Explanation of symbols]

 1 UV Light Emitting Lamp 2 Elliptical Reflector 3 Planar Reflector 4 Illumination Light 5 Input Lens 6 Fly's Eye Lens 7 Planar Reflector 8 Condenser Lens 9 Reticle 10 Projection Lens 11 Workpiece 12 Deformed Illumination Aperture 13 Deformed Illumination Aperture 14 Chiller 15 Liquid crystal controller 16 Main controller 17 Liquid crystal 18 Fly eye

Claims (3)

[Claims] 1. An illumination optical system for outputting illumination light,
Fly-eye to reduce the coherence of illumination light,
In a projection type exposure machine having an exposure mask for defining an exposure pattern, and a projection optical system for projecting the exposure pattern onto an object to be processed, in the vicinity of the fly eye, the illumination light passing through the fly eye A projection type exposure apparatus comprising an aperture for modified illumination capable of optically controlling the size and shape of a light beam. 2. The projection type exposure apparatus according to claim 1, wherein the modified illumination aperture has a panel structure having a liquid crystal shutter function. 3. The projection exposure apparatus according to claim 2, wherein the modified illumination aperture of the panel structure is an assembly of a plurality of liquid crystals.