JPH09232226A - Scan type aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor aligner which can shorten an exposure time by making it possible to form a rectangular emitting area of the part necessary to form a pattern on a mask without masking blade, eliminating the waste of the exposure light and increasing the illuminance on a wafer. SOLUTION: In the scan type aligner for emitting the light from an exposure light source 1 to a mask 6 via a fly eye lens 14 and projecting the pattern of the mask to a wafer via a projection optical system to expose it, the lens 14 is formed by arranging a plurality of rectangular piano-concave lenses L in contact with each other as seen in plane, and the light from the source 1 is incident to the lens 14. The emitting light becomes a slender elliptical luminous flux having a long lateral size, and the emitting light from the lens 14 is emitted to the mask 6 via a substantially rectangular condenser lens 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scan type exposure apparatus, and more particularly to a scan exposure apparatus having an improved illumination optical system for scan exposure in a semiconductor lithography process.

[0002]

2. Description of the Related Art In a semiconductor lithography process, scan exposure is a method of laterally expanding exposure light for a wafer. 7 and 8 show an example of a general scan type exposure apparatus used in a semiconductor lithography process. 7 and 8, reference numeral 1 is a light source, 4 is a fly-eye lens, 11 is a masking blade, 5 is a condenser lens, 6 is a mask (reticle), 7 is a projection optical system, and 8 is a wafer.

As the fly-eye lens 4, a combination of spherical lenses is generally used. The mask 6 and the wafer 8 are designed to be scanned in the direction of the arrow by a driving device (not shown). The light from the light source 1 is diffused by the fly-eye lens 4, and the slit 11a of the masking blade 11 limits the incident light to the condenser lens 5 to form an elongated elliptical shape 9 and the incident light is collimated by the condenser lens 5. A long elliptical irradiation area 10 necessary for pattern exposure is formed on the mask 6 as light, and the pattern of the mask 6 is projected onto the wafer 8 through the projection optical system 8 by this illumination light flux. By thus passing through the slit 11a, the performance guarantee region as the exposure apparatus optical system is limited to the slit region, and there is an advantage that aberrations such as distortion and image plane can be further reduced.

[0004]

However, in the conventional scanning type exposure apparatus as described above, the slit 11a of the masking blade 11 is used to form the elliptical irradiation area 10 on the mask 6. In the scan exposure, only a part of the light from the light source 1 is used, the exposure amount is reduced, and the throughput is reduced. Further, when the circular condenser lens 5 as shown in the figure is used for the illumination system, parts other than the elliptical shape 9 which is actually used for exposure are wasted. Moreover, if expensive quartz or fluorite is used for the glass material of the condenser lens 5, the cost will increase. The present invention has been made in view of the above-mentioned point, and it is possible to form a substantially rectangular irradiation area as much as necessary for pattern formation on a mask without using a masking blade, to eliminate waste of exposure light and on the wafer. It is an object of the present invention to provide a scan type exposure apparatus capable of increasing the illuminance and reducing the exposure time.

[0005]

To achieve the above object, the present invention irradiates a mask with light from an exposure light source through a fly-eye lens, and projects the pattern of the mask onto a wafer through a projection optical system. A scan type exposure apparatus for exposing, wherein the fly-eye lens is configured by arranging plano-concave lenses having a rectangular shape in plan view in close contact with each other two-dimensionally, and on the mask by the fly-eye lens, It is characterized in that a substantially rectangular irradiation region necessary for pattern formation is formed. According to the present invention, a condenser lens is arranged between the fly-eye lens and the mask, and the condenser lens is formed in a substantially long shape including at least a region necessary for exposure of the wafer. The present invention is also characterized in that the focus of the fly-eye lens is matched with the focus of the condenser lens on the light incident side.
The present invention is also characterized in that an excimer laser light source is used as an exposure light source, and light incident from the excimer laser light source through a vibrating mirror is collimated by a beam expander and is incident on the fly-eye lens.

In the present invention, the light from the fly-eye lens is directly applied to the condenser lens without passing through the slit. Since the fly-eye lens is a two-dimensional array of plano-concave lenses with a rectangular cross-section, the light emitted from the fly-eye lens becomes a horizontally long and slender elliptical light flux, and it is possible to collect light only in the area required for exposure. The amount of light per unit area on the wafer is increased, and the exposure time of the mask pattern is shortened. Further, the condenser lens only needs to be as wide as the irradiation area on the mask, so that the molding glass material of the condenser lens can be saved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings. In FIGS. 1 and 2, the same components and functions as those in FIGS. 7 and 8 are denoted by the same reference numerals. 1 is a light source, 14 is a fly-eye lens, and 15 is a condenser lens. Lens 1
The outgoing light of No. 4 is directly incident on the condenser lens 15, and the conventional masking blade 11 is not used. As shown in FIGS. 3 and 4, the fly-eye lens 14 is configured by arranging a plurality of plano-concave lenses L each having a rectangular shape in a plan view in close contact with each other in a two-dimensional manner. It is arranged toward the condenser lens 15.

As shown in FIG. 1, the condenser lens 15 is formed in a substantially elongated shape. Here, the substantially elongated shape may be any of an elongated rectangular shape, an elongated elliptical shape, or a combination thereof. Further, 6 is a mask, 7 is a projection optical system, and 8 is a wafer.
The light from the light source 1 enters the fly-eye lens 14 and enters the condenser lens 15 from the fly-eye lens 14. Since the fly-eye lens 14 is configured by arranging a plurality of plano-concave lenses L each having a rectangular shape in a plan view in close contact with each other two-dimensionally, the fly-eye lens 14 diverges light more than conventional spherical lenses and convex lenses. Since the angle is small and the light is rectangular, the emitted light also becomes a horizontally long and slender elliptical light 16 (see FIG. 1). As described above, since the light emitted from the fly-eye lens 14 has the elongated elliptical shape 16, the light flux does not protrude from the condenser lens 15 having a substantially long shape, and the entire light flux enters the condenser lens 15.

As shown in FIG. 6, the focal point F4 of the fly-eye lens 14 on the optical axis coincides with the focal point F5 of the condenser lens 15 on the incident side, whereby the light emitted from the condenser lens 15 is masked. A substantially rectangular irradiation area 10 can be formed on the surface 6. Further, by disposing the mask 6 at the position of the focal point F5 on the exit side of the condenser lens 15, the irradiation area 10 can be irradiated more uniformly.

The distance of the fly-eye lens 5 from the condenser lens 4 is adjusted so that the light emitted from the fly-eye lens 5 becomes a region close to the substantially rectangular irradiation region 10 (F4 and F5 in this state). Are the same). The pattern in the irradiation region 10 of the mask 6 is projected and exposed in the rectangular exposure region 12 of the wafer 8 via the projection optical system 7. The mask 6 and the wafer 8 are designed to be scanned in the direction of the arrow by a driving device (not shown).

FIG. 5 shows an embodiment of a scanning type exposure apparatus using an excimer laser as the light source 1. Reference numeral 2 is a vibrating mirror for preventing laser interference, and 3 is a beam expander. The laser beam emitted from the excimer laser light source 1 is converted into parallel light by the beam expander 3 and is incident on the fly-eye lens 14. To be done.
The scanning type exposure apparatus is not limited to the one shown in FIG. 5, and for example, the light source may be an excimer laser light source, a YAG
A laser, an argon laser, or an ultraviolet light source such as an Hg lamp may be used. The scan type exposure apparatus of the present invention is used not only for semiconductor devices such as ICs and LSIs, but also for various devices such as image pickup devices such as CCDs, liquid crystal panels (LCDs) and magnetic heads.

As described above, in the scan type exposure apparatus of the present embodiment, the fly-eye lens 14 constructed by arranging a plurality of plano-concave lenses L each having a rectangular shape in plan view in close contact with each other two-dimensionally is provided. By using it, the divergence angle of light can be reduced, and the fly-eye lens 14 can be used.
The light emitted from is an elongated elliptical light flux, and the light can be collected only in the area required for exposure. Therefore, the amount of light per unit area on the wafer 8 increases, and the exposure time of the mask pattern is shortened. Further, by making the focus of the plano-concave lens L forming the fly-eye lens 14 and the focus of the condenser lens 15 coincident, the irradiation area on the mask 6 can be uniformly irradiated. Further, the condenser lens 15 only needs to be as wide as the irradiation area on the mask 6, so that the molding glass material of the condenser lens 15 can be saved. In particular, it is expected that expensive glass materials such as quartz or fluorite will be used in the far infrared region in the future,
The effect of cost reduction is great.

[0013]

As described above in detail, according to the present invention, the light from the exposure light source is applied to the mask through the fly-eye lens, and the pattern of the mask is projected onto the wafer through the projection optical system to be exposed. In the scanning exposure device
The fly-eye lens is constructed by arranging plano-concave lenses having a rectangular shape in plan view in close contact with each other in a two-dimensional manner, and the fly-eye lens has a substantially rectangular irradiation area necessary for pattern formation on the mask. Has formed
The divergence angle of the light from the fly-eye lens can be reduced, and the light emitted from the fly-eye lens becomes an elongated elliptical light flux, which allows the light to be collected only in the area required for exposure. The amount of light of the mask pattern increases, and the exposure time of the mask pattern can be shortened. Further, according to the present invention, since the condenser lens disposed between the fly-eye lens and the mask is formed in a substantially long shape that includes at least a region necessary for exposure of the wafer, a molding glass material for the condenser lens 15 is formed. Can be saved. Furthermore, according to the present invention, since no masking plate is used,
The light from the light source can be effectively used without waste, and the waste of the exposure amount can be eliminated.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a scan type exposure apparatus of the present invention.

FIG. 2 is an explanatory diagram of a main part of FIG. 1;

FIG. 3 is a plan view of a fly-eye lens.

FIG. 4 shows a plano-concave lens of a fly-eye lens,
(A) is a plan view, (b) is a sectional view taken along line bb of (a),
(C) is the cc line cross section of (a).

FIG. 5 is a schematic side view showing an embodiment of a scan type exposure apparatus of the present invention.

FIG. 6 is a side view showing an enlarged main part of FIG.

FIG. 7 is a perspective view showing a schematic configuration of a conventional scan type exposure apparatus.

FIG. 8 is an explanatory diagram of a main part of FIG.

[Explanation of symbols]

 1 Light source (excimer laser) 2 Vibration mirror 3 Beam expander 6 Mask 8 Wafer 10 Irradiation area 14 Fly-eye lens 15 Condenser lens L Plano-concave lens F4 Fly-eye lens focus F5 Condenser lens focus

Claims (4)

[Claims] 1. A scan type exposure apparatus which irradiates a mask with light from an exposure light source through a fly-eye lens and projects the pattern of the mask onto a wafer through a projection optical system to expose the fly-eye lens. A plano-concave lens having a rectangular shape in a plan view is arranged in close contact with each other two-dimensionally, and a substantially rectangular irradiation area necessary for pattern formation is formed on the mask by the fly-eye lens. Scan type exposure equipment. 2. A condenser lens is arranged between the fly-eye lens and the mask, and the condenser lens comprises
The semiconductor exposure apparatus according to claim 1, wherein the semiconductor exposure apparatus is formed in a substantially elongated shape including a minimum area required for exposure of the wafer. 3. The scan type exposure apparatus according to claim 1, wherein the focus of the fly-eye lens is matched with the focus of the condenser lens on the light incident side. 4. An excimer laser light source is used as a light source for exposure, and light incident from the excimer laser light source through a vibrating mirror is collimated by a beam expander and incident on the fly-eye lens. The scan type exposure apparatus according to 1, 2 or 3.