JP3427226B2 - Exposure apparatus and exposure method - Google Patents

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial applications Conventional technology (Fig. 5) Problems to be Solved by the Invention (FIG. 5) Means for Solving the Problems (FIGS. 1 and 4) Action (Figs. 1 and 4) Example (FIGS. 1 to 4) The invention's effect

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, and can be applied to, for example, an exposure apparatus for exposing a large area pattern on a photosensitive substrate for manufacturing a liquid crystal display device.

[0003]

2. Description of the Related Art Conventionally, in this type of exposure apparatus, in order to cope with an increase in the size of a photosensitive substrate to be exposed, the exposure area of the photosensitive substrate is divided into a plurality of unit areas and the exposure is repeated according to each area. In some cases, a screen having a finally desired pattern is thereby synthesized over substantially the entire surface of the photosensitive substrate.

As shown in FIG. 5, in an exposure apparatus 1 for manufacturing a liquid crystal display device, an illumination light LA1 emitted from an ultra-high pressure mercury lamp 2 as an exposure light source is condensed by an elliptical mirror 3 and a shutter 4 is used. And enters the wavelength selection filter 6 via the reflection mirror 5. The wavelength selection filter 6 has a wavelength required for exposure (for example, a wavelength of 435 [nm] for g-line and a wavelength of 365 [n for i-line).
m]) only is transmitted.

Illumination light LA transmitted through the wavelength selection filter 6
1 is converted into a light flux having a uniform light amount distribution by a fly-eye integrator 7 and applied to a reticle blind 8. The reticle blind 8 constitutes a rectangular diaphragm, and the size and position of the opening S can be set arbitrarily.

A part of the luminous flux emitted from the fly-eye integrator 7 is reflected by the half mirror 9 and enters the integrated exposure amount meter 10, and the opening / closing time of the shutter 4 is controlled based on the information of the integrated exposure amount meter 10. The exposure amount is controlled by controlling 11

The illumination light LA1 that has passed through the opening S of the reticle blind 8 is reflected by the reflecting mirror 12 and is imaged on the reticle 14 for pattern projection by the condenser lens 13. As a result, the light flux set to have a predetermined size and position at the opening S of the reticle blind 8 is selectively applied to the irradiation area having an arbitrary size and position on the reticle 14.

The image of the pattern existing in the irradiation area on the reticle 14 is formed by the projection lens 15 on the photosensitive substrate 16 made of a glass plate. As a result, the photosensitive substrate 1
The image of the pattern on the reticle 14 is exposed in the specific regions 6 of the image. The photosensitive substrate 16 is placed on the stage 17.

The stage 17 is formed by stacking a pair of blocks movable in the X and Y directions which are orthogonal to each other in the horizontal plane. The position of this stage 17 is
It is detected by a laser interferometer system (not shown) that reflects the laser light 19 on the upper movable mirror 18 to monitor the position. As a result, the position of the photosensitive substrate 16 in the horizontal plane is adjusted.

Here, when synthesizing the screens of the patterns, the reticle 14 is finally exposed after one exposure is completed for the reticle 14 having the divided pattern of a certain divided area of the entire desired pattern. Exchange. Then, the stage 17 is driven to position and expose another exposure area of the photosensitive substrate 16 with respect to the projection lens 15. Thereafter, the same procedure is repeated each time the exposure is completed, so that the entire area of the photosensitive substrate 16 is exposed.

When synthesizing the screens of the patterns in this manner, the reticle 14 drawing error, the projection lens 15 aberration, the positioning error of the stage 17 for positioning the photosensitive substrate 16, and the like are combined at the boundary positions of the exposure areas. In order to prevent the occurrence of a break in the pattern, exposure is performed by superimposing a minute amount of the boundaries of the exposure areas.

[0012]

In the conventional image synthesizing method as described above, the overlay error of the exposure area changes discontinuously at the joint portion of the divided pattern due to the difference in lens aberration and positioning accuracy. Therefore, especially in the case of active matrix type liquid crystal devices,
Since the operating characteristics of the thin film transistor are affected, a difference occurs in the contrast at the connection portion of the exposure area. Since even a slight difference in contrast is easily perceived by human visual characteristics, the display quality of the device deteriorates if the contrast changes intermittently at the pattern seam.

To solve this, for example, Japanese Examined Patent Publication No. Sho 63-49218
As shown in No. 3, there is proposed a reticle or a filter to be superimposed on the reticle, which is provided with a light-reducing means for reducing the amount of transmitted light at a position corresponding to a joint portion of a divided pattern. According to this method, the exposure amount of the overlapping portion of the division pattern becomes substantially equal to the exposure amount of the other portion, and in addition to this, the use of the resist remaining at a certain exposure amount or more causes the division pattern The seam portion can be smoothly continuous.

However, in this method, since the reticle itself has a dimming characteristic, the number of man-hours for manufacturing the reticle is increased, and the possibility of pattern defects occurring during the manufacturing is increased, and the burden on the reticle manufacturing process is increased. is there.

On the other hand, it is conceivable to superimpose a filter having a predetermined dimming characteristic on the reticle. However, in this method, maintenance and management of the reticle is complicated because the reticle is more likely to be damaged or contaminated when the filter is attached or detached. Further, a pellicle having a certain thickness is generally provided before and after the reticle to prevent foreign matter such as dust from adhering to the divided pattern. Therefore, at least the filter and the reticle division pattern are separated by the thickness of the pellicle, which makes it difficult to obtain an ideal dimming characteristic on the division pattern. In addition, it is necessary to prepare a dedicated filter for each reticle, and the labor required for manufacturing and maintaining the filter cannot be ignored.

The present invention has been made in consideration of the above points, and it is not necessary to provide a reticle with a light-reducing characteristic or prepare a different light-reducing means for each reticle, and to obtain an ideal light amount on the reticle. An attempt is made to propose an exposure apparatus that can obtain a distribution.

[0017]

In order to solve the above-mentioned problems, an exposure apparatus according to a first aspect of the present invention is a fly-eye integrator (7) that comprises a light beam from a light source (2) and comprises a plurality of small lens groups (7A). Through the exposure pattern (P ₁ ,
The illumination optical system (2,3,5,32,6,12,13) guided onto the reticle (14) on which P ₂ ) is formed, and the illumination optical system (2,3,3) which is almost conjugate with the reticle (14). 5, 32,
6, 12 and 13), and illumination area setting means (8) for setting an illumination area on the reticle (14) illuminated by the light flux, and an entrance surface and an illumination area of the fly-eye integrator (7). The photo-sensitive substrate (15) is provided with a lens system (33) which makes the setting means (8) substantially conjugate with each other, and a projection optical system (15) which projects the light flux passing through the reticle (14) onto the photo-sensitive substrate (16). 16) An exposure apparatus for forming a desired pattern on a photosensitive substrate (16) such that a part of the exposure patterns (P ₁ , P ₂ ) overlaps different areas on the photosensitive substrate (16). , A light amount control means (31) arranged on the incident surface side of the fly-eye integrator (7) for adjusting the light amount of the light flux from the light source, and the exposure of the overlapping portion.
Driving the light quantity control means (31) so as to adjust the quantity.
And a moving mechanism . In the exposure apparatus according to the second aspect, the light amount control means (31) adjusts the light amount so that the exposure amount of the portion where the overlapping exposure is performed is equal to the exposure amount of the portion where the overlapping exposure is not performed. In the exposure method according to the third aspect, a part of the first pattern (P ₁ ) and the second pattern (P ₁ ) are generated by the light flux emitted from the fly-eye lens (7) composed of a plurality of small lens groups (7A). An exposure method for exposing a desired pattern by overlapping exposure of a part of ₂ ) on the photosensitive substrate (16), and an exposure amount for adjusting the exposure amount on the incident surface side of the fly-eye lens (7).
Overlapping exposure with the step of disposing the adjusting device (31)
Exposure amount adjusting device (31) for adjusting the exposure amount of the part
And driving the motor . In the exposure method according to the fourth aspect, the first pattern (P ₁ ) and the second pattern (P ₂ ) are formed on a common reticle. In the exposure method according to the fifth aspect, the first pattern (P ₁ ) and the second pattern (P ₂ ) are formed on different reticles. In the exposure method according to the sixth aspect, the first pattern (P ₁ ) and the second pattern (P ₂ ) are the same pattern.

[0018]

The light amount control means 31 for adjusting the light amount of the light beam LA1 from the light source 2 is arranged on the incident surface side of the fly-eye integrator 7 composed of a plurality of small lens 7A groups to expose pattern P.
The exposure dose distribution in the overlapping range of ₁ and P ₂ was arbitrarily controlled. Further, a lens system 33 is arranged so that the entrance surface of the fly-eye integrator 7 and the illumination area setting means 8 for setting the illumination area on the reticle 14 are substantially conjugate with each other. This allows the reticle 7 to have a dimming characteristic, or the reticle 7
It is not necessary to prepare different light reducing means for each, and an ideal light amount distribution can be obtained on the reticle 7.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, in which parts corresponding to those in FIG. 5 are designated by the same reference numerals, reference numeral 30 denotes an exposure apparatus for manufacturing a liquid crystal display device as a whole. In addition to the configuration of the conventional exposure apparatus 1, a fly eye 30 is provided. A diaphragm mechanism 3 is provided on the incident side of the integrator 7.
1 is arranged. The illumination light LA1 incident on the fly-eye integrator 7 has its light amount adjusted by the diaphragm mechanism 31, is converted into a light beam having an arbitrary light amount distribution, and is applied to the reticle blind 8.

A lens 32 is arranged between the reflecting mirror 5 and the wavelength selection filter 6, so that the illumination light LA1 incident on the wavelength selection filter 6 becomes substantially parallel. Further, a lens 33 is arranged between the fly-eye integrator 7 and the half mirror 9, so that the incident surface of the fly-eye integrator 7 and the reticle blind 8 have a conjugate positional relationship. This conjugation condition is
Since the exit surface of the fly-eye integrator 7 has a certain curvature as a lens, it is formed by this curvature and the lens 33.

Incidentally, the reticle blind 8 and the reticle 14 are provided with a conjugate positional relationship, and accordingly, the incident surface of the fly-eye integrator 7 and the reticle 14 are provided with a substantially conjugate positional relationship. .

As shown in FIG. 2, the fly-eye integrator 7 is formed by bundling a plurality of rod-shaped glass materials 7A having a rectangular cross section. The illumination light LA1 is made of the respective glass material 7A.
When the light is divided into two and is made incident, the respective glass materials 7A are made uniform and dispersed. As shown in FIG. 3, in the diaphragm mechanism 31, the diaphragm unit 31A is arranged on the incident surface side of each glass material 7A.

The diaphragm unit 31A has a horizontal axis 31 having substantially the same length as the width and height of the incident surface of the glass material 7A.
Two Xs and three vertical axes 31Y are arranged parallel to the upper and lower sides and the left and right sides of the incident surface. Horizontal axis 31X and vertical axis 3
1Y are connected to each other at their ends, thereby forming a rectangular light passage section that is substantially the same as the shape of the incident surface of the glass material 7A.

The two vertical axes 31Y are hinged to the bases of quadrilateral plate-shaped diaphragm blades 31R and 31L, respectively, and the tips of the diaphragm blades 31R and 31L face the glass material 7A side independently to the left and right. Rotate. The bases of diaphragm blades 31U and 31D each having a rectangular plate shape are hinged to the two horizontal axes 31X, and the tips of the diaphragm blades 31U and 31D are illuminated by the illumination light L.
It independently rotates up and down toward the side where A1 enters.

The ends of the two pulling wire members 34 are attached to the root of the diaphragm blade 31R. One of the two pull wires 34 is a drive mechanism (not shown).
When pulled by, the diaphragm blade 31R freely rotates in the diaphragm unit 31A, and the area of the light passage section can be narrowed to an arbitrary value according to the rotation angle. As a result, the amount of illumination light LA1 incident on the glass material 7A is reduced by the aperture blade 3
It is limited to a predetermined value according to the rotation angle of 1R.

The other diaphragm blades 31L, 31U, 31D can also freely rotate in the diaphragm unit 31A by the same driving mechanism. With this, the glass material 7A
The amount of illumination light LA1 incident on the diaphragm blades 31L, 31
It is limited to a predetermined value according to the respective rotation angles of U and 31D. The diaphragm unit 31A and the pulling wire member 34 are formed thin and small so as not to affect the illumination uniformity, so that the maximum area of the passage section of the illumination light LA1 is substantially the same as the incident surface area of the glass material 7A.

If the fly-eye integrator 7 is composed of, for example, n pieces of glass material 7A provided with n pieces of diaphragm unit 31A, diaphragm blades 31R _{1 to} 31R _n , 3
1L _{1 to} 31L _n , 31U _{1 to} 31U _n and 31D ₁ to
31D _n are arranged, and the amount of light incident on each glass material 7A is limited to a predetermined value by rotating only an arbitrary diaphragm blade to an arbitrary angle. As a result, the illumination light LA1 is converted into a light flux having an arbitrary light amount distribution and is applied to the reticle blind 8.

As described above, the reticle blind 8 is illuminated with the illumination light LA1 converted into a luminous flux having an arbitrary light amount distribution, and the size of the opening S is set to an arbitrary rectangular shape so that the reticle 14 is absent. When exposed to
As shown in (A), the right end portion and the left end portion 40A of the rectangular exposure images P ₁ and P ₂ whose exposure positions are completely separated with respect to the dimming regions 40 and 41 arranged on the right and left sides, respectively. And 41A, the exposure amount distribution may be set such that it becomes darker as it approaches 41A.

In the above structure, for example, when exposing the exposure images P ₁ and P ₂ , the following steps are performed so that the dimming regions 40 and 41 overlap each other within a predetermined range.

That is, as shown in FIG. 4 (B), when the exposure image P ₁ is first exposed, the reticle blind 8 is moved so that the dimming area 40 corresponding to the dimming start line 41B of the dimming area 41. The area from the connecting line 40B to the right end portion 40A is shielded from light. Then, the arbitrary aperture unit 31A is controlled to set the exposure amount distribution so that the exposure amount decreases substantially linearly from the dimming start line 40C of the dimming region 40 and becomes 0% at the position of the connection line 40B. And expose.

When exposing the exposure image P ₂ , similarly, the dimming area 4 corresponding to the dimming start line 40C of the dimming area 40 is formed.
The range from the connection line 41C in 1 to the left end 41A is shielded. Then, the exposure amount distribution is set so that the exposure amount decreases almost linearly from the dimming start line 41B and becomes 0% at the position of the connection line 41C, and the exposure is performed.

As a result, as shown in FIG. 4 (C), the dimming start line 40C and the connecting line 41C coincide with each other and the connecting line 4
An exposure image is formed so that 0B and the dimming start line 41B are connected so as to coincide with each other. In this overlapped exposure range, the exposure amount distributions are added together, and as shown in FIG. 4 (D), the exposure amount in the non-dimmed range and the overlapped exposure range are the same.

Therefore, an ideal light amount distribution can be given to the divided pattern on the reticle 14 without any modification to the reticle 14, and if the divided pattern on the reticle 14 is repeatedly exposed and combined on the photosensitive substrate 16. It is possible to obtain an image of a combined pattern in which the joints of the divided patterns are smoothly continuous.

According to the above configuration, the diaphragm mechanism 31 for adjusting the light amount of the illumination light LA1 is arranged on the incident surface side of the fly-eye integrator 7 to arbitrarily set the exposure amount distribution in the overlapping range of the exposure images P ₁ and P _2. By controlling the reticle 14 in this manner, it is not necessary to provide the reticle 14 with a dimming characteristic or prepare different dimming means for each reticle 14, and an ideal light quantity distribution can be obtained on the reticle 14.

In the above-described embodiment, the case where the two exposure images P ₁ and P ₂ are combined has been described, but the present invention is not limited to this, and finally desired by three or more exposures. The same applies to the case where the screens of the entire pattern are combined. For example, in the case of composite exposure of four divided pattern images divided into upper, lower, left, and right, the same exposure as above is performed so that the contrast difference is inconspicuous in the range of the center of the screen, which is exposed in duplicate by four exposures. Also in this case, the same effect as described above can be obtained.

In the above embodiment, the horizontal axis 31X
And the vertical axis 31Y is connected to each other at their ends to form the diaphragm unit 31A.
The present invention is not limited to this, and can be applied to the case where the diaphragm unit is configured without the horizontal axis and the vertical axis being directly connected.

Further, in the above-described embodiment, the diaphragm blades 31R, 31L, 31U and 31 are attached to the diaphragm unit 31A.
Although the case where D is arranged and the diaphragm blades 31R, 31L, 31U, and 31D are operated by the pulling wire 34 has been described, the present invention is not limited to this, and, for example, only one diaphragm blade may be arranged. Any number of blades, structure, and operation method may be used.

Further, in the above-described embodiment, the case where the exposure device 30 in which the diaphragm mechanism 31 is disposed on the incident surface side of the fly-eye integrator 7 is used to expose the photosensitive substrate 16 for manufacturing a liquid crystal display device is described. The present invention is not limited to this, and for example, an exposure device for exposing a photosensitive substrate or a semiconductor substrate for manufacturing a plasma display, etc., is provided with a light amount control means on the incident surface side of a fly-eye integrator to expose an arbitrary exposure target. It can be widely applied to exposure apparatuses.

Further, in the above-mentioned embodiment, the case where the divided patterns are synthesized by the step-and-repeat type projection exposure to finally obtain the desired synthesized pattern has been described, but the present invention is not limited to this, and the mirror project is not limited thereto. It can also be widely applied to the case where the divided patterns are combined by another exposure method such as projection exposure of the exclusion method to finally obtain a desired combined pattern.

Further, in the above-described embodiment, the case where the light amount of the illumination light LA1 incident on the fly-eye integrator is mechanically limited by the diaphragm mechanism 31 has been described, but the present invention is not limited to this, and the fly-eye integrator can be used. The present invention can be widely applied to the case where the amount of incident illumination light is controlled by a light amount control means capable of arbitrarily adjusting the amount of transmitted light such as an ND filter, a liquid crystal, and an element for electrically adjusting the amount of transmitted light.

The plurality of division patterns to be combined on the photosensitive substrate 16 may be formed on the same reticle or different reticle respectively. Further, one kind of divided pattern may be used, and the desired combined pattern may be finally formed by repeatedly exposing this divided pattern.

[0043]

As described above, in the exposure apparatus according to the first and second aspects, the light quantity control means for adjusting the light quantity of the light flux from the light source is arranged on the incident surface side of the fly-eye integrator.
In addition, since the drive mechanism drives the light amount control means to arbitrarily control the exposure amount distribution in the overlapping range of the exposure patterns, it is necessary to provide the reticle with a light reduction characteristic or prepare a different light reduction means for each reticle. It is possible to obtain an ideal light amount distribution on the reticle. Further, the exposure method according to any one of claims 3 to 6 includes the step of driving the exposure amount adjusting device for adjusting the exposure amount of the overlapping exposure portion on the incident surface side of the fly's eye lens. The exposure amount of the overlapping portion with the second pattern can be adjusted arbitrarily.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an exposure apparatus according to the present invention.

FIG. 2 is a perspective view provided for explaining a fly-eye integrator.

FIG. 3 is a perspective view for explaining a diaphragm unit.

FIG. 4 is a schematic diagram showing an exposure amount distribution for explaining the composition of exposure images.

FIG. 5 is an overall configuration diagram for explaining a conventional exposure apparatus.

[Explanation of symbols]

1, 30 ... Exposure device, 2 ... Ultra high pressure mercury lamp, 3 ...
… Elliptical mirror, 4 …… Shatter, 5, 12 …… Reflecting mirror, 6…
… Wavelength selection filter, 7… Fly-eye integrator, 7A… Glass material, 8… Reticle blind, 9
...... Half mirror, 10 ...... Integrated exposure meter, 11 ...... Control device, 13 ...... Condenser lens, 14 ...... Reticle, 15 ...... Projection lens, 16 ...... Photosensitive substrate, 17 ......
Stage, 18 ... Moving mirror, 19 ... Laser light, 31 ...
... Diaphragm mechanism, 31R, 31L, 31U, 31D ... Diaphragm blade, 31X ... Horizontal axis, 31Y ... Vertical axis, 32, 33 ...
... Lens, 34 ... Tensile wire.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01L 21/30 527 (56) References JP-A-61-267722 (JP, A) JP-A-5-6849 (JP, A) JP-A-57-112753 (JP, A) JP-A-5-304076 (JP, A) JP-A-63-62230 (JP, A) JP-A-2-3907 (JP, A) JP-A-5-267124 (JP, A) JP-A-5-281508 (JP, A) JP-B-63-49218 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027 G03B 27 / 32 G03B 27/72 G03F 7/20 521

Claims (6)

(57) [Claims] 1. An exposure pattern in which a light flux from a light source is passed through a fly-eye integrator composed of a plurality of small lens groups.
And an illumination optical system that guides the light onto the reticle on which the lens is formed, and an illumination area setting unit that is disposed at a position in the illumination optical system that is substantially conjugate with the reticle and that sets an illumination area on the reticle illuminated by the light flux. And a projection optical system for projecting the light flux that has passed through the reticle onto a photosensitive substrate, and a lens system for arranging the incident surface of the fly-eye integrator and the illumination area setting means in a substantially conjugate position. In an exposure apparatus for forming a desired pattern on the photosensitive substrate such that a part of the exposure patterns overlap with each other for different regions, the exposure device is disposed on the incident surface side of the fly-eye integrator. ,
Light amount control means for adjusting the light amount of the light flux from the light source, and the light amount adjusting means for adjusting the exposure amount of the overlapping portion.
An exposure apparatus comprising: a drive mechanism for driving the node device . 2. The light amount control means adjusts the light amount so that the exposure amount of the portion subjected to the overlapping exposure becomes equal to the exposure amount of the portion not subjected to the overlapping exposure. Exposure equipment. 3. A light beam emitted from a fly-eye lens composed of a plurality of small lens groups exposes a part of the first pattern and a part of the second pattern on the photosensitive substrate in an overlapping manner, thereby forming a desired pattern. In the exposure method for exposing the fly-eye lens, a dew for adjusting the exposure amount on the incident surface side of the fly-eye lens
A step of providing a light quantity adjusting device, and the exposure to adjust the exposure quantity of the overlapping exposure portion.
And a step of driving a light amount adjusting device . 4. The exposure method according to claim 3, wherein the first pattern and the second pattern are formed on a common reticle. 5. The exposure method according to claim 3, wherein the first pattern and the second pattern are formed on different reticles. 6. The exposure method according to claim 3, wherein the first pattern and the second pattern are the same pattern.