JPS61280619A - Exposing device - Google Patents

Abstract

PURPOSE:To enable to perform a uniform exposure on a wafer in a scanning type exposing device by a method wherein pulsed laser beam is irradiated on the wafer each time the scanning position reaches the prescribed positions at equal intervals. CONSTITUTION:Pulse-status laser beam, which is irradiated from an excimer laser light source 2, is made to diverge from its focal position F by a convex cylindrical lens 3, is reflection-condensed by a ring-band type spherical mirror 4, is turned into circular arc slit-shaped light in the Y direction and is irradiated on a mask M, while the carriage carrying the mask M and a water W thereon is made to shift to the X direction, electrical pulse for laser irradiation generates each time an index 6 passes through the graduations of a graduated scale 7 and lastly the circuit pattern of the mask M is exposed on the whole surface of the wafer W. As a pulse exposure is performed spacially and at equal intervals on the wafer W each time the carriage is made to shift as much as the slit width L to the scanning direction, an exposure can be performed continuously, and at the same time, uniformly on the wafer W.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to exposure equipment, and is particularly suitable for semiconductor exposure equipment. [Prior Art] Semiconductor technology is becoming increasingly integrated and miniaturized.

Optical exposure methods are also expanding into new areas with the development of lenses with high release power. In such semiconductor exposure equipment, when transferring and printing a circuit pattern on a mask or reticle onto a wafer, the line width of the circuit pattern printed on the wafer is proportional to the wavelength V of the optical name. In recent years, light sources with short wavelengths in the deep ultraviolet (Deep LIV) region have been used.

Conventionally, this type of deep ultraviolet light source includes deuterium lamps and Xe lamps.
- Hg lamps are known, but these light sources have low output in the far ultraviolet region, and the sensitivity of the photoresist material applied on the wafer4 is low compared to the α resist used in general link graffiti. Since the exposure time is low, the exposure time is long and the throughput is low.

On the other hand, in recent years, it has been discovered that an excimer laser, a high-output light source in the dsep UV region, is an effective means for exposure apparatuses. However, the Ex7Mer laser is a conventional deuterium lamp.

Unlike the Xe-Hg lamp, it uses a pulse oscillation method, so it is difficult to simply use this type of laser light in a reflection projection exposure device that performs exposure by scanning a small screen of light such as a slit. Generally difficult.

[Problems to be solved by the invention and means for solving them]

SUMMARY OF THE INVENTION An object of the present invention is to provide an exposure apparatus capable of performing slit scanning type exposure using a pulse-ratio laser beam.

Furthermore, the present invention provides an exposure apparatus 1 that does not require constant scanning speed control.
The purpose is to provide

This purpose is achieved by irradiating pulsed laser light every time the scanning position reaches a predetermined position at equal intervals. Here, while an index is provided on the carriage on which the object to be scanned by the slit is placed, on the other hand, an equally spaced scale P having an interval of, for example, the slit width is provided on a stationary reference table. Generate a signal for pulse irradiation.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
Figures (1) and (b) are longitudinal cross-sectional views of a reflection projection scanning type exposure apparatus according to an embodiment of the present invention. FIG. 1(a) is a plan view of the illumination part l of FIG. 1(b).

Here, the object moves relative to the arc-shaped slit beam S shown in FIG. 1(a) in the direction of the arrow (scanning direction) in FIG. 1(b) to transfer the pattern in each slit area.

Note that FIG. 1(c) shows the excimer laser light intensity distribution in the scanning direction.

In FIG. 1(e), L is the slit width, which is the half width, that is, the interval between the positions where the light intensity is 50 inches.

As a result, the light intensity distribution in the scanning direction is made uniform by overlapping the tail portions.

In the illumination section l, the excimer laser light source 2 is, for example, K
A light source containing rF and XeC1 and generating nine pulsed laser beams, each with 248 points (KrF).
, 308 m (Xs C1), which produces light 'kR with a wavelength in the deep ultraviolet region. Along the optical path of the light source 2, a convex cylindrical lens 3 or toric lens made of a material that completely transmits deep ultraviolet light, and an annular spherical mirror 4 are arranged.

Along the optical path reflected by the spherical mirror 4), a reflection type projection optical system 5. A wafer W is placed. The mask M and the wafer W are integrally carried by a structure (carriage) not shown and are movable in the direction (X direction) shown in FIG. 1(b).

In this embodiment, the projection optical system 5 is an equal-culture irrigation system.

Mano, 6 is an index attached to the carriage (moving table).

Reference numeral 7 denotes equally spaced scale marks provided on a stationary reference stand paired therewith, and the interval between the scale marks corresponds to the slit width on the image plane, that is, the exposure area in the scanning direction. 8 is a signal transmission system, and 9 is a slit for forming the slit light s2.

At the bottom, the pulsed laser beam irradiated by the excimer laser light source 2 is diverged from the focal point F by the convex cylindrical lens 3.

The light is reflected and focused by the annular spherical surface fs4 as shown in Fig. 1(b).
The mask M is irradiated with the Vc arc slit-shaped light in a direction perpendicular to the plane of the paper (in the Y direction).

On the other hand, the carriage carrying the mask M and the wafer w2 moves in the X direction, and the mask MO circuit pattern is finally exposed on the entire surface of the wafer W.

That is, as the carriage moves, an electric pulse for laser irradiation is generated each time the mark 6 attached to it passes through the scale 7. The combination of the index and the scale may be made by a magnetic means such as a Magnescale, a laser interferometric length measuring machine, a photoelectric means such as an encoder, or an electric switch means provided at equal intervals. In particular, a laser interferometric length measuring machine provides the highest accuracy.

The electric pulses thus generated are converted by the signal transmission system 8 into appropriate pulses for triggering the oscillation of the excimer laser 2, causing the excimer laser 2 to oscillate. In addition,
If the generated pulses can be used as they are to trigger the oscillation of the excimer laser 2, this signal transmission system 8 is unnecessary.

In this way, pulse exposure is performed every time the carriage moves by the width of the slit in the scanning direction, that is, at equal spatial intervals, so that the wafer W can be exposed continuously and uniformly.

By the way, the pulse emission time of excimer laser is usually lO ~
Since it is very short at 20 n5ac, there is no problem even if the carriage is moved continuously.

In addition, the uniformity of the exposure light in the scanning direction was confirmed by using a fly-eye lens. 0, or if the intensity distribution is shaped uniformly using a filter, aperture, etc., further improvement can be achieved.

It should be noted that if the scale 7 is set in the scanning direction (2) and the width of the exposure area is made sufficiently small, overlapping exposure will not occur, so that the illuminance uniformity of the exposure light in the scanning direction will not be much of a problem.

However, in this case, a large number of pulses are required to expose one wafer, which accelerates gas deterioration of the excimer laser.

Note that the index 6 and the scale shift may be provided on the scale shift and the index tW stop. Also, this indicator (or scale) may be provided on the mask side carriage instead of the wafer side carriage.

In the embodiments described above, the projection optical system 5 may be a reduction storage system. At this time, since the numerical aperture on the image side increases, it is expected that the resolution will improve.

However, it is necessary to change the scanning speed according to the reduction ratio.

〔effect〕

As explained above, according to the present invention, uniform exposure is possible in a scanning type exposure apparatus.

Furthermore, since the exposure trigger is performed based on equally spaced scale marks, there is no need to scan the carriage at a constant speed.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are diagrams of one embodiment of the present invention,
Figure 1(b) is a vertical cross-sectional view, Figure 1(a) is Figure 1(b)
FIG. 1(e) is a plan view of the excimer laser light intensity distribution in the scanning direction. In the figure, M is a mask, W is a wafer, 2 is an excimer laser light source, 6 is an index, 7 is a scale, 8 is a signal transmission system, and 9 is a slit.

Claims (1)

[Claims] 1. In an exposure apparatus that scans a slit light relative to a pattern on a first object and transfers the pattern to a second object via a projection optical system, An exposure apparatus comprising: means for forming a slit beam; and means for generating the pulsed laser beam every time the scan position of the scan reaches a predetermined position at equal intervals. 2. The exposure apparatus according to claim 1, wherein the distance corresponds to the slit width. 3. The exposure apparatus according to claim 1, wherein the projection optical system is a same-magnification imaging system. 4. The exposure apparatus according to claim 1, wherein the projection optical system is a reduction imaging system.