JPS60158449A - exposure equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an exposure apparatus, and is particularly suitable for a semiconductor exposure apparatus.

[Prior art] Semiconductor liquid technology is becoming more and more highly integrated and miniaturized, and optical exposure methods are also expanding their scope with the development of high M image power and the development of 7Z. In such semiconductor exposure equipment, the circuit pattern on the mask or reticle is
When transferring and baking onto \F-, wafer 1. Since the resolution line fl of a printed circuit pattern is proportional to the wavelength of the light source, in recent years light sources with short wavelengths in the deep ultraviolet (Deep IJV) region have been used.

Conventionally, this type of deep ultraviolet light source includes deuterium lamps and Xe lamps.
- Known as Hz lamps, these light sources are characterized by continuous operation in principle, even when operated with direct current or alternating current.

However, these light sources have low output in the deep UV region, and the photoresist material coated on the sea urchins has low sensitivity, resulting in long exposure times and low throughput.

-On the other hand, in recent years, it has been learned that an excimer laser, a high-output light source in the deep tlV region, can be used as a right-handed means for exposure equipment. However, excimer lasers use conventional deuterium lamps.

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

[Purpose] An object of the present invention is to eliminate the above-mentioned problems, and to realize an exposure apparatus by synchronizing the pulse interval of pulsed laser light and the scanning speed of exposure.

However, if the pulse interval of the laser beam and the scanning speed are not accurately synchronized, uneven exposure may occur. In other words, even if a rectangular beam with a light intensity is obtained from the laser beam as shown in FIG. 2(a), as shown in FIG.
), when the pulse interval is slower than the scanning speed, the exposure overlaps in some areas as shown in FIG. 2(C), making it impossible to obtain uniform exposure. Therefore, it is required to manage the synchronization of scanning and pulse generation with high precision, and a second object of the present invention is to reduce the precision.

[Example] An example of the present invention will be described below with reference to the drawings. 1st
FIG. 1(a) is a longitudinal sectional view of a reflection projection scanning type exposure apparatus according to an embodiment of the present invention, and FIG. 1(b) is an f-plane view of the illumination section 1 of FIG. 1(a). .

In the illumination section 1, an excimer laser light source 2 is provided.

For example, it is a light source that is filled with Kr, F, or Xe(l) and generates a pulsed laser beam, each with 24811
1 (KrF) and 308 mm (XeCL), which generates light with a wavelength in the far ultraviolet region. Along the optical path of the light source 2, a convex cylindrical lens 3 made of a material that transmits deep ultraviolet light or a Dolly lens, and an annular spherical mirror 4 are arranged.

Along the optical path reflected by the spherical mirror 4, a mask M, a reflective projection optical system 5, and a wafer W are arranged. The mask M and the wafer W are integrally supported by a structure (carriage) not shown and can be moved in the direction (X direction) shown in FIG. Ru.

In the L configuration, the pulsed laser light emitted by the excimer laser light source 2 is diverged from its focal point F by the convex cylindrical lens 3, reflected and condensed by the annular spherical mirror 4, and is reflected as shown in FIG. 1(a). in the direction perpendicular to the paper surface (X
direction), the light becomes an arcuate slit-shaped light and is irradiated onto the mask M.

Although commercially available excimer laser light sources generate rectangular light, the light intensity is high in the center, so the light in the X direction (scanning direction) of the slit-shaped light irradiated onto the mask M is The strength is approximately an isosceles trapezoid as shown in FIG. 1(c). Normally, when using the luminous flux emitted from a light source, the irregular region is cut through an aperture, but in the present invention, the decrease in intensity at both ends can also be used as is. However, if accurate isosceles formation or light with an isosceles triangular or rectangular light intensity distribution (described later) is required, the light path of the illumination section 1 may be placed at any position, for example, position A, and the center =
An ND filter whose transmittance is uniform and whose transmittance gradually decreases by 4.0 mm toward both ends, or a light attenuating element whose transmittance decreases from the center toward both ends is arranged.

On the other hand, the carriage carrying the mask M and the wafer moves in the X direction, so that the circuit pattern of the mask M is exposed over the entire surface of the wafer W. Here, the width of the light intensity distribution of one pulse of laser light is L (m), the scanning speed is V (m/s),
-The number of pulse repetitions of laser light per profit is N (times/s)
The light sources 2. The exposure unevenness in the scanning direction can be eliminated by controlling the pulse and carriage so that the maximum values of the respective pulses coincide near the half value as shown in FIGS. 2(a) and 2(Cb). However, in this case, the shape of the light intensity distribution of one pulse is assumed to be an isosceles triangle, an isosceles platform, or a shape substantially similar thereto. In addition, FIGS. 4(a) and (b) are
This shows a case where the light intensity distribution of the slit-shaped light is rectangular and the pulse interval is synchronized with the scanning speed.

Next, a case where the pulse interval or scanning speed of the pulsed laser light varies will be described.

In other words, when the light intensity distribution shape is rectangular as shown in Fig. 5, if the scanning speed is too slow or the pulse interval is too short, the bits and pieces [i] of each pulse may not be actually exposed. Since the exposure is made ΔX in front of the desired position in the scanning direction, and the exposure amount is doubled in the interval Δχ where the pulses overlap, subsequent chemical processing is often difficult. On the other hand, in the case of a shape in which the light intensity distribution decreases at both ends as shown in Fig. 1, for example, when the oblique sides of an isosceles trapezoid overlap in the middle, even if the positional deviation occurs by ΔX, in the normal case, Compared to the case where the light intensity distribution is rectangular, the exposure unevenness is comparatively smaller and more favorable. Controlling the light intensity distribution shape into an isosceles square or an isosceles trapezoid is itself possible because the beam intensity distribution of commercially available laser light sources usually has a round shape, so the laser beam cross section and the irradiated surface are optically controlled. This is possible by making the laser beam conjugate, but if an ND filter is used to shape the part where the laser light intensity is almost uniform, as shown in A in Figure 1(a)Cb),
more effective.

[Effects] As explained above, according to the present invention, in a scanning type exposure apparatus, the scanning speed and the pulse interval of the pulsed laser are cycled.

Uniform exposure becomes possible. Furthermore, if the cross-sectional shape of the pulsed laser beam in the scanning direction is selected so that the front and rear ends are lowered, synchronized control of scanning and pulse generation becomes easier.

[Brief explanation of drawings]

Figure 1 (a> is a vertical sectional view of an embodiment of the present invention. Figure 1 (b) is a T: side view 1 of Figure 1. Figure A1 (c) is a slit in Figure 1. Light intensity distribution diagram in the scanning direction of shaped light, second
IN to FIG. 6 are graphs showing pulse intervals, scanning speeds, and synchronization states. 2... Excimer laser light source 6... Synchronous control device procedural amendment (self-control April 16, 1985 Commissioner of the Japan Patent Office 1, Indication of the case 1988 Patent application No. 013318
No. 2, Name of the invention Exposure device 3, Relationship with the person making the amendment Patent applicant, (100) Canon Co., Ltd. 4, Agent address: 1-9-20-6 Akasaka, Minato-ku, Tokyo, Contents of the amendment (1) Correct "aperture" in line 17 of page 5 of the specification to "aperture". (2) Correct the "width" on the 9th line of page 6 of the specification to "[1], half value 11]". (3) Change “-interest” to “-second” on page 6, line 10 of the specification
Correct to. (4) Change “Figure 2” to “Figure 3” on page 6, line 14 of the specification.
Correct to 1. (5) "By conjugating" on page 7, line 20 of the specification is amended to "by conjugating". (6) Add the following sentence after "It will be easy." on page 8, line 11 of the specification. Note: In the two consecutive embodiments, we have described a reflection type exposure device that scans in a slit shape to form an image at the same magnification, but a refraction type exposure device may also be used, and it also scans in a slit shape. For example, a Dyson optical system may be used as a projection optical system to scan in a rectangular shape. Furthermore, the exposure apparatus is not limited to an exposure apparatus that forms an image at the same magnification, but may also be an exposure apparatus that forms a reduced image. In this case, the mask M and the wafer W may be moved synchronously not at the same speed but at a speed ratio according to the reduction ratio. . ”

Claims (3)

[Claims] (1) In an apparatus that scans a pattern on a first object and exposes a second object, an illumination means for irradiating pulsed laser light, and an interval between pulses of the laser light and the scanning speed are synchronized. An exposure apparatus having a 4"r feature. (2) A means for making the cross-sectional shape of the light intensity distribution in the scanning direction of the light irradiated from the illumination means to the object @l substantially into an equilateral triangle or isosceles trapezoid; Claim 1, characterized in that the standing speed and the pulse interval of the laser beam are synchronized so that the pulse of the light source coincides with approximately half the maximum ip'i of the light intensity of the shape. Exposure equipment. (3) The exposure apparatus according to claim 1, wherein the illumination means includes an excimer laser, an optical member that diverges the laser light, and a condensing member that condenses the light into an arc shape.