JPH08305035A - Illumination device and exposure method using the same - Google Patents

Abstract

PURPOSE: To realize spot-illumination with prescribed size and sufficiently uni form light intensity distribution by a compact and inexpensive device. CONSTITUTION: This illumination device A is provided with a condensing and reflecting member 2 condensing light from an illumination light source 1, a rod-like optical integrator 3 receiving the light passed through the reflecting member 2 from one end, integrating it and emitting it from the other end and a projection lens system irradiating a surface to be irradiated with illumination luminous flux by projecting the emitting surface of the integrator 3 on the surface to be irradiated with the prescribed size. By illuminating the local part 11b of the surface to be exposed 11a being the surface to be irradiated by the illumination device A through a mask 12 and relatively moving the illumination device A side and the surface to be exposed 11a and the mask 12 sides, the prescribed area of the surface to be exposed 11a is scanned and exposed. Then, a mask pattern is transferred on the surface to be exposed 11a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminator suitable for exposure used in the manufacture of semiconductor devices and liquid crystal display devices, and an exposure method using the same.

[0002]

2. Description of the Related Art The exposure method includes a proximity exposure method which is a so-called proximity exposure method.

In this exposure method, a glass substrate or a wafer coated with a photosensitizer (hereinafter simply referred to as a substrate) and a mask are supported in close proximity to each other, and illumination light is irradiated from above the mask to expose the mask pattern to the photosensitizer. Is to be transferred to. Compared with the projection exposure method, this exposure method does not require a complicated lens system or a highly accurate stage, so that the cost can be easily reduced. Further, as compared with the contact exposure method, since the mask and the substrate are not in direct contact with each other, a defect due to peeling of the photosensitive agent is less likely to occur.

As shown in FIG. 4, the conventional proximity exposure apparatus uses a mercury lamp a as a light source and collects light from the mercury mirror a by a condenser mirror b, and then bends an optical path by a cold mirror k, or As it is, it is integrated through the fly-eye lens c and the aspherical mirror m to form an illumination light flux n with a uniform light intensity distribution for spot irradiation with a predetermined size, which is locally applied to the exposed surface d of the substrate g. The light is projected through the mask e. Scanning exposure is performed by relatively moving the illumination system side and the exposed surface d and the mask e side by projecting light locally, so that a predetermined area is exposed and the mask pattern can be transferred.

The resolution of such a proximity exposure method depends on the gap between the exposed surface d and the mask e. The minimum line width that can be resolved is ds, the wavelength of the light source is λ, and the gap between the mask e and the exposed surface d of the substrate g is G.
Then, it is represented by ds = √ (2λG), and when the line width of about 3 μm required for manufacturing a liquid crystal display device is resolved by using the mercury lamp a as the light source as described above, the gap G Needs to be about 10 μm.

However, the exposed surface d of the substrate g is a general one and has a waviness of about 10 to 20 μm. To deal with this, the exposure apparatus of FIG. 4 supports the substrate g by a flattening chuck h and moves it to a height measuring station (not shown) adjacent to the exposure station shown in the figure to move the exposed surface of the substrate g. The exposed surface d is flattened by measuring the height of d and adjusting the vertical movement element i in the flattening chuck h based on the measurement result.

As a result, the gap G between the exposed surface d and the mask e is made uniform, and then the gap G between the exposed surface d and the mask e is required by adjusting the z stage j.
After setting to about μm, the scanning exposure is performed by moving to the exposure station shown in the figure.

According to such scanning exposure, a large-diameter condenser lens is not required as in the case of the whole surface collective exposure method, and the cost of the apparatus is reduced. There is also an advantage that magnification correction becomes easy.

[0009]

However, in the above-mentioned prior art, the fly-eye lens c is used to integrate the light from the mercury lamp a to the illumination light beam n for spot irradiation with a predetermined size for scanning exposure. And the aspherical mirror m are used, and these need to be manufactured with high precision in a special shape, so that the illumination device is still expensive. Also,
The optical path length of the integrating system including the fly-eye lens and the aspherical mirror of the illuminating device is relatively long, which causes an increase in the size of the entire illuminating device. Further, the fly-eye lens c may be downsized in order to downsize the illumination device, but in this case, the fly-eye lens c becomes too fine and is not practical.

Therefore, a lighting device capable of solving these problems is desired, but a device satisfying this is not yet provided.

The inventors of the present invention have conducted various studies and repeated experiments, and as a result, have found that a small and simple optical member exhibits the required integral function.

An object of the present invention is to solve the above-mentioned problems of the related art, and by adopting an optical integrating element and combining it with a normal projection optical system, a compact and inexpensive device can be provided with a predetermined size. An object of the present invention is to provide an illuminating device capable of spot illuminating with a sufficiently uniform light intensity distribution and an exposure method using the same.

[0013]

In order to achieve the above-mentioned object, the illumination device of the present invention has a condensing / reflecting member for condensing light from an illuminating light source and a light passing through the condensing / reflecting member. A rod-shaped optical integrator that receives the light from one end, integrates it, and emits it from the other end, and a projection lens that illuminates an illumination light beam on the illuminated surface by projecting the exit surface of this optical integrator on the illuminated surface in a predetermined size. It is characterized by having a system.

Further, in the exposure method of the present invention, the illumination device illuminates a local area of the exposure surface, which is an irradiation surface of the illumination light flux, through a mask, and the illumination device side and the exposure surface and the mask side are illuminated. By relatively moving, a predetermined area of the exposed surface is scanned and exposed, and the mask pattern is transferred to the exposed surface.

[0015]

In the above-described structure of the illuminating device of the present invention, the light from the illumination light source condensed by the condensing / reflecting member is received by the rod-shaped optical integrator from one end and emitted from the other end. At this time, the optical integrator integrates the light received from one end by the rod shape while repeating various reflections on the inside of the side circumference until the light is emitted from the other end, and the light intensity distribution is uniform over the entire emission surface of the optical integrator. Since it is emitted as a luminous flux having a certain size, it is possible to obtain an illumination luminous flux suitable for uniformly illuminating a spot with a predetermined size using only one small and simple optical member. The exit surface of the optical integrator can be formed by a projection lens system. Predetermined local illumination can be achieved with high accuracy only by projecting a predetermined size on the illuminated surface, and the device can be made small and inexpensive without degrading the performance.

Further, in the exposure method of the present invention, by using the illuminating device, a local area of the surface to be exposed, which is the surface to be exposed, is masked by a uniform illumination light beam for spot irradiation with a predetermined size from the device. The illumination device side and the exposure side and the mask side are moved relative to each other to scan a predetermined area of the exposure surface, and the uniform local illumination is applied to the predetermined area. Since the exposure is performed over the entire area, the mask pattern can be transferred with high accuracy by evenly exposing the exposed surface in a wide range by uniform illumination. Moreover, since the illuminating device is small, by performing the scanning exposure by moving the illuminating device, the supporting structure and the driving device for the scanning exposure can be downsized, and the illuminating device can be moved from the exposed surface range. Since the problem that it greatly protrudes is also eliminated, the entire device becomes small and inexpensive.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an illuminating device of the present invention and an exposure method using the same will be specifically described below with reference to the drawings.

1 and 2 schematically show an illumination apparatus A as a first embodiment of the present invention and an exposure apparatus B using the illumination apparatus A as a whole.

As shown in FIG. 1, the illuminating device A receives an elliptic mirror 2 which is a condensing / reflecting member for condensing light from a mercury lamp 1 as an illuminating light source, and the light passing through the elliptic mirror 2 from one end. Optical integrator 3 that integrates and emits from the other end, and a projection lens system 4 that projects the emission surface of the optical integrator 3 onto the illuminated surface in a predetermined size.
It has and.

Of course, a light source other than the mercury lamp 1 may be used depending on the application and various conditions. And in this embodiment,
Light collected by the elliptical mirror 2 is cold mirror 5
And an optical fiber 6 are made to enter one end of the optical integrator 3. The projection lens system 4 is shown in FIGS.
As shown in FIG. 3, the lens group 4a and the lens group 4b are composed of two groups, and a reflection mirror 7 is provided in the middle between them to bend the optical path at a right angle. The cold mirror 5, the optical fiber 6, and the reflection mirror 7 can be omitted, or another one can be adopted. However, it is convenient to appropriately select and use the cold mirror 5, the optical fiber 6, and the reflection mirror 7 in order to avoid the interference of the optical path with others and to arrange the required members collectively in a specific range.

The light from the mercury lamp 1 condensed by the elliptical mirror 2 in the illuminating device A section passes through the cold mirror 5 and the optical fiber 6 and is rod-shaped optical integrator 3.
The light is received from one end as shown in FIG. 1 and is emitted from the other end as shown in FIGS. At this time, since the optical integrator 3 has the rod shape, it integrates the light received from one end while repeating various reflections inside the side circumference until the light exits from the other end.

With such an integrating function, the optical integrator 3 emits a light beam having a uniform light intensity distribution C as shown in FIG. Therefore, it is possible to obtain the parallel light beam 10 suitable for uniformly irradiating a spot with a predetermined size by using only one small and simple optical member by the rod-shaped optical integrator 3.
By simply projecting the exit surface of the optical integrator 3 onto the illuminated surface by the projection lens system 4 in a predetermined size, predetermined local illumination can be achieved with high accuracy, and the device can be made small and inexpensive without degrading the performance. It is effective when applied to proximity exposure and various other types of local illumination.

The experimental data of this embodiment shown in FIG. 3 is for the case where the optical integrator 3 has a square cross-sectional shape, and favorable results are obtained. However, the present invention is not limited to this, and it is needless to say that the cross section may have various shapes such as a triangle and a rectangle.

The illumination light flux is finally shaped by the shaping mask 8 into a predetermined size and shape. This may be provided if necessary.

When the reflecting surfaces forming the optical integrator 3 are flat surfaces and the facing surfaces are parallel to each other,
The absolute value of the angle of each light ray with respect to the optical axis when the light flux enters the optical integrator 3 does not change even when passing through the optical integrator 3.

Therefore, the angular dependence of the intensity distribution of the illumination light beam 10 irradiated on the surface to be illuminated by the projection lens system 4 is substantially similar to that of the light beam incident on the optical integrator 3. If the illumination luminous flux 10 has an angle dependence on the intensity distribution, it may adversely affect the performance when using this illumination device. In that case, it is effective to provide an angular distribution smoothing means for reducing the angular dependence of the intensity distribution of the light incident on the optical integrator 3. As a means therefor, a transmissive surface or a reflective surface having an uneven surface can be used. For example, a plate having irregularities on the surface may be installed immediately before the optical integrator 3 to transmit light. Although light travels in the optical fiber 6 while being reflected, the natural bending of the optical fiber 6 plays a role of unevenness, and therefore the light may pass through the optical fiber 6.

In the exposure apparatus B using the above-described illumination apparatus A shown in FIG. 1, the exposed surface 11a of the glass substrate 11, which is the irradiated surface of the illumination light flux 10, to which the photosensitive agent is applied is close to this. Proximity exposure is performed through the mask 12,
The case where the mask pattern is transferred to the photosensitive agent forming the exposed surface 11a is shown.

The exposure apparatus B illuminates the local area 11b of the exposed surface 11a through the mask 12 by the illumination apparatus A, and relatively moves the illumination apparatus A side and the exposed surface 11a and the mask 12 side, A predetermined area of the exposed surface 11a is scanned and exposed.

For this scanning exposure, an XYθ stage (not shown) that can move on the gantry in orthogonal XY2 directions,
A substrate 11 is supported via a quartz chuck 13 shown in the figure by a Z stage which can be moved in the Z direction, and an illuminator A is a Y stage which can be moved in the Y direction on a mount (not shown). The X stage 14 shown in the figure which can be moved in the X direction and the Z stage 15 which can be moved in the Z direction on the X stage 14 support the position adjustment of each part for the exposure and the substrate 1
The gap G between the first exposed surface 11a and the mask 12 is adjusted and the scanning for the exposure is performed. This scanning is performed intermittently so as to satisfy the required exposure time for each local area 11b.

As a result, the illuminator A has the X stage X
It is possible to freely move within the XY plane by moving the Y stage in the Y direction and moving in the Y direction, and it is possible to perform scanning exposure by moving over the entire predetermined exposure band of the exposed surface 11a of the substrate 11. During this exposure, the XYθ stage is slightly moved in the same direction as the scanning direction in synchronization with the scanning of the illuminating device A, so that error distribution can be achieved, and the mask pattern can be magnified and transferred to the substrate 11.

The gap G is adjusted for each local area 11b exposed by the illumination device A by intermittent scanning. This will be described. The exit portion of the illumination light flux 10 provided with the shaping mask 8 of the illumination device A is a nozzle as shown in FIG. 1, and jets the compressed air supplied from the air source 22 through the air pipe 21. , The mask 12 is locally deformed. When the pressure at the nozzle outlet is P and the sectional area of the nozzle is S, the force applied to the mask 12 is PS. Specifically, the size is 3
When a mask having a size of 60 mm × 465 mm and a thickness of 4 mm and a nozzle having a cross-sectional area of 4 cm ² is used, a pressure P of several hundred g / cm ^{2 is} required to bend the mask 12 by several tens of μm. The pressure P at the nozzle outlet depends on the distance between the tip of the nozzle and the upper surface of the mask 12, and increases when the illumination device A is lowered, and the amount of deformation of the mask 12 also increases.

On the other hand, the gap G between the exposed surface 11a of the substrate 11 and the mask 12 is measured by the laser reflection type gap measuring means 23, and the output signal of the result of this measurement and the gap set by a setting device (not shown). By driving the Z stage 15 of the illumination device A by an amount corresponding to both deviation signals from the signal, the gap G is always set as set. As a result, scanning exposure is achieved with high resolution over the entire area.

Particularly in this embodiment, a port is formed around the nozzle of the illumination device A, and the vacuum source 3 is provided through the vacuum pipe 31.
A suction port is formed by connecting the two. As a result, the illumination light flux 10 of the mask 12 is obtained at this suction port.
You can pull up the area around the
By further locally deforming the mask 12, the mask 12 and the exposed surface 11a of the substrate 11 can be brought closer to each other, and a higher resolution can be obtained. However, such a configuration may be applied if necessary.

When scanning exposure is performed using the illumination device A as described above, the local illumination 11 on the surface 11a to be exposed is irradiated with a uniform illumination light beam 10 from the device A which illuminates the spot with a predetermined size.
b is illuminated through the mask 12, and by moving the illuminator A side and the exposed surface 11a and the mask 12 side relatively, a predetermined area of the exposed surface 11a is scanned and the uniform Since a wide range of local illumination exposes a predetermined area, the exposed surface 11a having a wide area
However, the mask pattern can be transferred to the exposed surface 11a with high accuracy by performing uniform exposure by uniform illumination. Moreover, since the illuminating device A is small, the scanning exposure is performed by moving the illuminating device A, so that the supporting structure and the driving device for the scanning exposure are downsized, and the illuminating device A is exposed to the exposed surface 11
Since a large protrusion around the range of a is also eliminated, the entire device becomes small and inexpensive.

[0035]

According to the illumination device of the present invention, an illumination light flux suitable for uniformly illuminating a spot with a predetermined size by using only one small and simple optical member, and the exit surface of the optical integrator is a projection lens system. With this, a predetermined local illumination can be achieved with high accuracy simply by projecting a predetermined size on the surface to be illuminated, so that the device can be made small and inexpensive without degrading the performance.

Further, according to the exposure method of the present invention, a predetermined area of the surface to be exposed is scanned and exposed with a uniform illumination light beam which is spot-irradiated with a predetermined size from the illumination device. It is possible to transfer a mask pattern with high accuracy even on a wide range of exposed surfaces based on uniform illumination. Moreover,
Since the illuminating device is small, by performing the scanning exposure by moving on the side of the illuminating device, the supporting structure and the driving device for the scanning exposure can be downsized, and the illuminating device can be enlarged from the exposed surface range to the surroundings. Since the protrusion is also eliminated, the entire device becomes small and inexpensive.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an illumination device and an exposure apparatus using the same as one embodiment of the present invention.

2 shows an integration system and a projection system of the lighting device of FIG.
(A) is the vertical cross-sectional front view, (b) is the top view.

FIG. 3 is an explanatory diagram showing a relationship between a cross-sectional view of a parallel light beam obtained by the lighting device of FIG. 1 and a light intensity distribution.

FIG. 4 is a schematic configuration diagram showing a conventional illumination device and an exposure apparatus using the same.

[Explanation of symbols]

 A illumination device B exposure device 1 illumination light source 2 condensing reflection member 3 optical integrator 4 projection lens system 11 substrate 11a exposed surface 11b local 12 mask G gap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeo Sato 3-10-10 Higashisanda, Tama-ku, Kawasaki City, Kanagawa Matsushita Giken Co., Ltd. (72) Inventor Kaji Fujita 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Denki Sangyo Co., Ltd.

Claims (7)

[Claims] 1. A light collecting and reflecting member that collects light from an illumination light source, a rod-shaped optical integrator that receives light from the light collecting and reflecting member from one end, integrates it, and emits it from the other end, and this optical integrator. And a projection lens system for irradiating the irradiation surface with an illumination light flux by projecting the exit surface of the irradiation surface onto the irradiation surface with a predetermined size. 2. The illumination device according to claim 1, further comprising an angle distribution smoothing unit that reduces the angle dependence of the intensity distribution of the light incident on the optical integrator. 3. The illuminating device according to claim 2, wherein the angle distribution smoothing means comprises a transparent surface having irregularities on the surface. 4. The illuminating device according to claim 2, wherein the angle distribution smoothing means comprises a reflecting surface having irregularities on the surface. 5. The illuminating device according to claim 4, wherein the angle distribution smoothing means comprises a tunnel through which light surrounded by a reflecting surface having irregularities passes. 6. The lighting device according to claim 5, wherein the tunnel is formed of an optical fiber. 7. The illumination device according to claim 1 illuminates a local area of an exposed surface, which is an illuminated surface, through a mask, and relatively moves the illumination device side and the exposed surface and the mask side. An exposure method comprising: scanning a predetermined area of the surface to be exposed to perform exposure to transfer a mask pattern onto the surface to be exposed.