JPS60241035A - Exposing device - Google Patents

Abstract

PURPOSE:To obtain high resolution and to perform large-area exposure by providing a fly eye lens which rotates by the proper number of times during exposure synchronously with a shutter which cuts off exposure luminous flux to some part of an optical system. CONSTITUTION:An exposure light beam emitted by a mercury vapor lamp 12 is reflected and converged through an elliptic concave surface mirror 13 and incident on the 1st mirror 15, and the reflected exposure luminous flux L enters a convex lens 33 through a shutter 18. Further, the exposure luminous flux L is so converged slightly as to strike only one-side end surfaces of all lenses 29 of the fly eye lens 17 through the concave lens 33. The exposure luminous flux L exiting from the fly eye lens 17 is incident on the 2nd mirror 20 and reflected to a collimator mirror 21 at a specific angle of reflection. When the exposure luminous flux L is incident on individual convex lenses 29 of the fly eye lens 17, projection images formed by the assembly of all convex lenses 29 and 29J are superimposed on each other and couples of lenses (a) and (a), (b) and (b)... move close to and away from each other to select a reduction and an enlargement area; and the number of lenses 29 is increased to uniform the illuminance on a plane on the whole.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exposure apparatus for printing a mask pattern onto a work coated with photoresist. Generally, such exposure apparatuses include contact type exposure apparatuses, proximity type exposure apparatuses, projection type exposure apparatuses, and the like. The present invention relates to a proximity exposure apparatus and provides a proximity exposure apparatus that is suitable for manufacturing workpieces that require a large area of exposure surface and that requires a pattern accuracy of approximately 5 to 10 μm by providing a proximity gap. be.

FIG. 1 is a schematic configuration diagram showing a conventional proximity type exposure apparatus. A mask 2 is placed above the surface of the workpiece 1 coated with photoresist at a predetermined distance apart, and the pattern of the mask 2 is printed by projecting the exposure light beam 3 onto the workpiece 1. Reference numeral 4 denotes a light source of a mercury lamp, and the radiation emitted from the light source is reflected and condensed by a pair of elliptical concave mirrors 5. The focused exposure light beam 3 is reflected by the first cold mirror 6, in which only the ultraviolet rays required for exposure are reflected, passes through the fly's eye lens 7, further passes through the next cold mirror 6, and becomes a parallel beam by the collimator lens 8. The exposure light flux 3 of such parallel light rays is irradiated onto the mask 2 . A proximity gap D is provided between the workpiece 1 and the mask 2.

The mask 2 is arranged so as not to come into contact with the resist surface of the work 1. The fly's eye lens 7 has a function of making the exposure light beam 3 uniform in brightness over the entire exposure surface. Here, the light beam 4 is generally a xenon-mercury lamp, and its emitted light is 365r+m, 400n
m and 435 nm emission line spectra.

These emission lines are partially in phase, and are coherent, meaning that each emission line has only one part of the total radiation.
The presence of ~5% coherent light is observed. FIG. 2 shows an enlarged view of the positional relationship between the workpiece 1 and the mask 2, and the mask 2 has slits or cutouts 9 forming a pattern. Assuming that the width of this cutout 9 is l, the exposure light beam 3 is diffracted at the end face (edge) of the mask 2, producing a Fresnel diffraction pattern on the resist surface. Therefore, for example, in a 365 nm emission line, when the geometric distance X from directly below the edge changes, bright and dark "stripes" (cons 1 to last) occur with respect to that X. The conditional expression that produces a stripe is defined by the wavelength of the exposure light beam 3, λ, and the proximity gap.If the distance from directly below the edge is X, it becomes clear when f'; ■
7゜p -D-12m+1) (7) Toki09 ,'X,
# , bn edited version.

becomes. At this time, m is a natural number 1.2.3..., and the proximal position is adopted as D>λ (that is, when camp D is approximately 400 μm, λ is approximately 0.4 μm).

A contrasting pattern of brightness and darkness is produced at the positions shown in both of the above equations.

For example, the two-dimensional pattern of the mask 2 shown in FIG. 3(A) causes irregular distortions on the workpiece 1 at the periphery, particularly at the corners, as shown in FIG. 3(B). Exposure luminous flux 3
Although it is not a completely coherent ray, it is 1-5%
Since the bright line has a certain degree of coherence, it has an adverse effect on the reproducibility and resolution of the mask 2 on the workpiece 1 in pattern production. In this way, the burning of the mask 2 has become a major problem in the process.

On the other hand, exposure apparatuses have already been developed that eliminate the interference of exposure light beams, use electron beams or X-rays as light sources, or employ a non-aberration projection optical system. However, such an exposure apparatus has the problem that it requires a complicated lens system and a sophisticated electronic circuit to control the apparatus, resulting in an expensive exposure apparatus.

This invention was made in view of the problems of the conventional technology.The invention solves the above problems by employing a fly-eye lens as part of the optical system, which rotates an appropriate number of times during exposure in synchronization with a shutter that blocks the exposure light flux. The purpose is to resolve the issue. In addition, a fly-eye lens is constructed by combining a large number of lens groups and a large number of corresponding lens groups, and by moving the corresponding lenses closer to each other, the exposure area can be arbitrarily reduced or expanded to create a pattern of any size. The aim is to provide an exposure device that can be adapted to various types of work. The present invention will be explained below based on drawings and principle diagrams. In FIGS. 4 to 8, the box 11 has a mercury lamp 12 as a light source.
The mercury lamp 12 is of a short arc type, for example, the distance between the electrodes is 1-2, and the output is approximately IKW. The simplest source of strong ultraviolet light is light generated by a discharge in dilute mercury gas. An elliptical concave mirror 13 is fixed to the box body 11 so as to surround the mercury lamp 12, and the elliptical concave mirror 13 has an opening 14 facing upward in FIG. □ A first mirror 15 is provided above the box 11 at a position facing the opening 14, and the center point of the first mirror 15 and the center point of the opening 14 are located approximately on the same line. At the same time, the reflective surface of the first mirror 15 is inclined at a predetermined angle with respect to the line connecting these center points, that is, the incident light beam. Elliptical concave mirror 1
3 and the first mirror 15 constitute a first optical system.

The box body 1 is located at a position facing the reflected light beam from the first mirror 15.
A fly-eye lens 17 is rotatably provided on the side wall 16 of the mirror 1 with a structure as described later, and the center point of the fly-eye lens 17 and the center point of the first mirror 15 are approximately on the same straight line. positioned.

A shutter 18 is interposed between the fly-eye lens 17 and the first mirror 15 and is attached to the box body 11, and this shutter 18 has a hysteresis morph 19 with a reduction gear.
It is designed to be driven by.

The box body 11 is located at a position facing the rear surface of the fly eye lens 17.
is provided with a second mirror 20, and the center point of the second mirror 20 and the center point of the fly-eye lens 17 are located approximately on the same line, and the reflective surface of the second mirror 20 is located at the center point of the fly-eye lens 17. The cotton connecting the points is inclined at a predetermined angle with respect to the incident light beam. In this way, the shutter 18 and the fly's eye lens 17 are interposed between the first mirror 15 and the second mirror 20. A large collimator mirror 21 is provided above the box body 11 at a position facing the reflected light beam from the second mirror 20, and the center point of the second mirror 20 and the center point of the collimator mirror 21 are different from each other. The collimator mirrors 21 are located substantially on the same straight line, and are mounted so that the reflected light from the collimator mirror 21 is directed substantially perpendicularly to the lower surface of the box body 11. The second mirror 20 and the collimator mirror 21 are the second mirror 20 and the collimator mirror 21.
It constitutes the optical system of This collimator mirror 21
The mirror reflects the incident light from the second mirror 20 into parallel light beams, and those with a diameter of 40,011 mm or more are in practical use, and are easier to manufacture and cheaper to obtain than transmission-type condenser lenses.

Reference numeral 22 denotes a workpiece whose surface is coated with photoresist, and a mask 23 on which a predetermined pattern is drawn is arranged in parallel with a predetermined proximity gap D on the upper surface of the workpiece 22. These work 22 and mask 23
are held by a known chuck (not shown), and their surfaces are perpendicular to the light beam incident from the collimator mirror 21.

Next, FIG. 5 is an enlarged view showing the fly's eye lens 17 and its surrounding area, and 25 is a substrate fixed to the side wall 16. A perfectly circular through hole 26 is provided at one end of this substrate 25.
is formed, and one annular sleeve 27 is rotatably inserted into this through hole 26.

One end of a cylindrical holder 2B is coaxially and rotatably inserted into the inner periphery of this sleeve 27, and this holder 28
holds a fly's eye lens 17 on the inner periphery.

Reference numeral 30 designates an upper sleeve for holding down into which the other end of the holder 28 is rotatably inserted, and this upper sleeve 30 is fixed to the substrate 25 by a holding plate 31 or the like.

Between these sleeves 27 and the upper sleeve 30, regular protrusions etc. are formed on the outer peripheral surface 32 of the holder 2 for engagement with a belt to be described later, and the upper end surface of the holder 28 has a large Hollow cylindrical part 3 containing a convex lens 33 with a diameter
4 are fixed coaxially.

Therefore, the fly's eye lens 17 is
7 and is rotatably supported by the side wall 16 via an upper sleeve 30.

An upper frame member 50 is fitted and fixed inside the upper end of the holder 28, and a large number of small diameter convex lenses 29 (a, b, c...
) are fixedly installed on the same plane. These 1121st
Group convex lens 29 (a.

b, c...) are all parallel to the axis of the holder 28. A lower frame member 5 is provided inside the lower end of the holder 28.
1 is slidably inserted in the axial direction, and the lower frame member 51
Similarly, a large number of small diameter convex lenses 29J (a, b, c, . . . ), for example, 8 to 50, are fixedly installed on the same plane inside the lens. These convex lenses 29J' of the second lens group
(a, b, c...) Each of the convex lenses 29 (a, b
, c...chi corresponds to each other, and each lens a-a, 'b
-b, c-c, . . . each have the same optical axis.

Through holes are formed in both ends of the upper frame member 50 in parallel with the optical axis, and adjustment shafts 52 and 53 are slidably inserted into these through holes. Threaded portions 54.55 are formed at the lower ends of the two adjustment shafts 52.53, and these threaded portions 54.55 have the same pinch and fit into the tapped holes formed at both ends of the lower frame member 51. It's embedded. A gear 56.57 with external teeth formed on the upper end of the adjustment shaft 54.55
are provided coaxially, and a portion of the external teeth of gears 56 and 57 protrude from notches 58 and 59 formed in the cylindrical portion 34, respectively.

Reference numeral 60 denotes an internal gear having teeth formed on its inner periphery, and the cylindrical portion 35 is loosely inserted inside the internal gear 60.
The internal teeth of No. 0 and the gears 56 and 57 mesh with each other. The internal gear 60 is prevented from being removed by a collar formed on the outer periphery of the cylindrical portion 34 and a retaining spring ring.

Therefore, when the internal gear 60 is rotated, the gears 56, 57
, the adjustment shafts 52.53 rotate, and the lower frame member 51 is moved by the convex lens 29J (a, b,
c...) and the convex lens 29 of the upper frame member 50 (a,
b, c...) They are moving closer to each other.

In FIG. 5, the gears 56 and 57 are shown enlarged for explanation, but they can be formed to a size that does not interfere with the exposure light flux passing through the convex lens 33.

Next, a support plate 35 is attached to the other end of the substrate 25 with bolts or the like, and a controllable induction motor 36 is mounted on this support plate 35. This induction motor 36 is connected to a reducer 37, and an output shaft 38 of the reducer 37 protrudes between the substrate 25 and the support plate 35.

This output shaft 38 has a boot I formed with a protrusion on its outer circumferential surface.
J-39 is fixed coaxially, and this pulley 39
A drive belt 40 having an inward grooved portion is wound between the outer peripheral surface 32 of the holder 28 and the outer peripheral surface 32 of the holder 28 .

Therefore, due to the rotation of the induction motor 36, the fly-on lens 17 and the convex lens 33 are moved against the sleeve 27. It is adapted for rotation via the upper sleeve 30.

The motor 19 that drives the shutter 18 and the induction motor 36 are connected to a control circuit 42 shown in FIG.
The rotation is controlled according to a predetermined relationship.

Next, the operation of this invention will be explained.

The exposure light beam emitted from the mercury lamp 12 is reflected and condensed by an elliptical concave mirror 13, and the light beam is condensed and incident on a first mirror 15. The exposure light beam reflected by the first mirror 15 passes through the shutter 18 and enters the convex lens 33.

Further, the exposure light beam is slightly converged by the convex lens 33 so that it is swallowed by one end surface of all the lenses 29 of the fly's eye lens 17.

The exposure light beam exiting the fly eye lens 17 is transferred to the second mirror 2.
0 and is reflected toward the collimator mirror 21 at a predetermined reflection angle.

As shown in FIGS. 6 and 7, the illuminance distribution on the virtual plane γ in front of the fly's eye lens 17 is concentric as shown in FIG. This is because the arc image is enlarged by the elliptical enclosure 13 and the image is projected. point O in rc,
-B If the illuminance inside the P circle is 100, then the illuminance inside the Q circle is 80.
．． The inside of the R circle is 6o, and the inside of the S circle is 50, etc. Next, when the exposure light beam enters each convex lens 29 of the fly's eye lens 17, it undergoes the following action. Now considering the pair of lenses 29, 29J (a-a), the virtual plane β of the rear surface of lenses 29, 29J (a-a)
Above, two quarters of the concentric circles P, Q, R, and S, ie, region a, are projected over the entire β plane.

Now, when the convex lens 29 J (al moves away from the convex lens 29 (δ) in the direction of the arrow, the a region projected on the β plane becomes the reduced al shown by the imaginary line; conversely, when it approaches, it expands. Similarly, the seventh As shown in the figure, the first Luns group and the second
In the lens group, that is, the convex lenses 29 and 29J, (b-b) projects the bM region, (c-c) projects the C region, and (dd) projects the 4w4 region onto the β plane.

Therefore, all convex lenses 29, 29J (a-a.

The projections made by the aggregates of lenses bb, cc, ...) are superimposed, and the projections of each pair of lenses (a-a, bb, c-
c, . . .) move away from and approach each other at the same time, resulting in a reduced area al (bl, cl . . .) shown by a virtual line.

It becomes possible to change the enlarged area a (b, c, . . . ) shown by a solid line.

In this way, the illuminance distribution is expanded and overlapped over the entire area due to the unevenness of the distribution, so that by increasing the number of lenses 29, the illuminance on the plane becomes uniform as a whole.

In fact, the exposure light beam 3 incident on the second mirror 20 has a uniform illuminance distribution, and this exposure light beam 3 is reflected toward the collimator mirror 21. The collimator mirror 21 converts this exposure light beam 3 into parallel light beams (collimated).
The light is irradiated onto the mask 23 as shown in FIG.

Further, by the movement of the convex lenses 29J (a, b, c...), the final parallel rays are formed by the mask 23 as shown in FIG.
It is possible to change from the reduced area indicated by the virtual line above to the enlarged area indicated by the dotted line. Therefore, it is possible to accommodate masks and workpieces of arbitrary sizes without waste.

Further, the induction motor 36 is driven by the control circuit 42, and the decelerated output shaft 38 is driven by the pulley 39. The fly-eye lens 17 is rotated via the drive belt 40.

The exposure time of the shutter 18 is controlled by the rotation speed of the hysteresis morph 19, but the rotation speed of the fly-eye lens 17 can be arbitrarily set with respect to this exposure time by a control circuit.

For example, it can be set to 4 rotations per second for an exposure time of 1 second.

The exposure light flux leaving the mercury lamp 12 in this way contains several percent of bright lines and vectors, that is, coherent components, but when it passes through each lens 29 of the fly-eye lens 17, first of all, A portion of the spectrum is disturbed, and by further rotating the fly's eye lens 17, the remaining coherent bright line spectrum is also converted into a nearly incoherent light beam.

Then, the mask 23 is irradiated with a non-coherent beam of exposure light, and the pattern on the mask 23 is printed onto the workpiece 22 without producing any interference stripes.

According to the inventor's experiments, as shown in FIG.
When the rectangular pattern (A) is printed on the workpiece 22 with a pattern width of 5 to 30 μm and a proximity gap of 10 to 400 μm, if the fly-eye lens 17 is not rotated, On the other hand, when the fly's eye lens 17 was rotated at a predetermined speed, a printed pattern with clear peripheral boundaries as shown in FIG. 3C was obtained.

The pattern 5 manufactured by the exposure apparatus of the present invention is a large workpiece and requires a pattern accuracy of around 10 μm for grids that must be printed with a proximity gap, especially for liquid crystals, thermal printers, or Suitable for manufacturing hybrid IC patterns.

As explained above, according to the present invention, by rotating the fly-eye lens, a strong incoherent surface light source can be obtained, and it is possible to obtain an inexpensive and high-resolution light source that can expose a large area. This provides the advantage of being able to provide an exposure apparatus that is easy to handle.

In addition, it can handle masks, patterns, and workpieces of any size without waste, and the pattern can be reduced or enlarged as necessary.

[Brief explanation of drawings]

Figure 1 is a schematic configuration diagram showing a conventional proximity exposure device;
Figure 3 is a diagram explaining the principle of interference, Figure 3 is a printing diagram of a mask obtained with a conventional exposure apparatus, Figure 4 is a front view showing the exposure apparatus of the present invention, and Figure 5 is a diagram of the exposure apparatus of the present invention. An enlarged sectional view of the main part, Figure 6 is a diagram showing the illuminance distribution, Figure 7 is a diagram explaining uniformity of the illuminance distribution,
FIG. 8 is a printing diagram of a mask obtained by the exposure apparatus of the present invention. 12... Mercury lamp (light source) 15... First mirror 17.
...Fly eye lens 18 Shutter 20...Second mirror 21...Collimator mirror 22...Wafer (work) 23...Mask L...Exposure light flux 2
9.29J... Convex lens patent applicant Oak Manufacturing Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A light beam that generates an exposure light beam, a first optical system that focuses the exposure light beam, a second optical system that makes the light beam focused by this first optical system enter and projects it onto an exposure surface, and this first optical system that In the exposure apparatus, a shutter is provided between the first optical system and the second optical system, and a shutter is provided between the first optical system and the second optical system. A plurality of 1171st groups whose axes are parallel to each other and arranged on a plane, and these 1171st groups and each lens have the same optical axis and are arranged on a plane so that they can be approached and separated from the 1171st group. 1. An exposure apparatus comprising a fly-eye lens comprising a plurality of second lens groups, the fly-eye lens rotating an appropriate number of times during exposure in conjunction with the shutter.