JPH1012521A - Coating method of resist and its apparatus, and method of alignment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating method of resist and its apparatus, capable of forming an arbitrary position and size of uncoated area of the resist on the substrate, without peeling off the resist, and capable of directly detecting the alignment mark with an exposure light, through the projection optical system of the projection aligner. SOLUTION: A wafer W is loaded on the rotary stage 4. A shaft 6 of the rotary stage 4 rotates, driven by the rotary mechanism 12 and rotates the rotary stage 4. A resist outlet 8, exhaling resist 10 to the surface of the wafer W, is positioned above the front of the rotary stage 4 where the wafer W is loaded. The resist outlet 8 is movable to an arbitrary position above the stage, in parallel with the front of the rotary stage 4 controlled by the outlet position controller 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for applying a photosensitive agent on a substrate in a photolithography process in the manufacture of a semiconductor device, a liquid crystal display device, and the like, and an exposure position adjusting method.

[0002]

2. Description of the Related Art A plurality of laminated circuit patterns are formed by a photolithography process on a semiconductor substrate (semiconductor wafer) used for manufacturing a semiconductor device or on a glass substrate used for manufacturing a liquid crystal display device. In the photolithography step, a photomask or a reticle (hereinafter referred to as a reticle) is formed on a photosensitive agent (resist) layer formed to a predetermined thickness on a semiconductor substrate or a glass substrate (hereinafter referred to as a substrate) using a projection exposure apparatus. ) Expose and transfer the circuit pattern formed thereon. Then, using the photosensitive agent layer to which the pattern has been transferred as a mask, the underlying semiconductor layer, oxide film, and the like are patterned to form a desired circuit.

[0003] The element characteristics of a semiconductor element to be formed largely depend on the processing accuracy such as the size and shape of a plurality of circuit patterns laminated on a substrate, and also on the overlay accuracy between the laminated layers. Therefore, when exposing the reticle pattern to the photosensitive agent layer on the substrate, it is necessary to accurately align the substrate and the reticle. This alignment is performed by observing alignment marks (hereinafter, referred to as alignment marks) formed on the substrate and the reticle with a microscope provided in the projection exposure apparatus.

For detecting the alignment mark, light having a wavelength different from the wavelength of the exposure light of the projection exposure apparatus (non-exposure light) is generally used. It is ideal for accuracy to observe the alignment mark of the reticle and the wafer at the same time with the same exposure light as the actual exposure state.However, even if the alignment mark is irradiated with the exposure light, This is because most of the exposure light is absorbed by the photosensitive agent layer which is exposed with high efficiency, and it is difficult to detect the reflected light from the alignment mark.

Further, since the projection optical system of the projection exposure apparatus corrects aberration only for light near the exposure wavelength, the alignment marks on the reticle and the wafer deviate from conjugate and cannot be observed simultaneously. Further, a wavelength range in which a sufficient transmittance can be obtained by a projection optical system using an excimer laser or the like as an exposure light source is limited to around ultraviolet light. Therefore, even if the above-mentioned non-exposure light is incident on the projection optical system so as to pass through the photosensitive agent layer above the alignment mark, it becomes necessary to correct the aberration of the projection optical system with respect to the non-exposure light, and Sufficient transmittance cannot be obtained. For these reasons, it is difficult to detect and align the alignment mark under the photosensitive agent layer using only the exposure light source and the projection optical system of the projection exposure apparatus.

Therefore, a dedicated correction optical system for correcting aberrations caused by using the non-exposure light is inserted into the projection optical system, or the non-exposure light is aligned using an observation optical system provided separately from the projection optical system. A method of irradiating on a mark is also performed. However, with these methods,
It is unavoidable that a change in the wavelength of the non-exposure light due to a change in temperature, a change in the optical characteristics and position of the correction optical system, or a change in the positional relationship between the observation optical system and the projection optical system may cause an alignment error.

On the other hand, a method of observing an alignment mark by directly exposing exposure light to a reticle and a substrate through a projection optical system by peeling off a photosensitive agent layer formed on the alignment mark is disclosed in Japanese Unexamined Patent Publication No. No. 224929. This method utilizes a photosensitive agent peeling region formed on an outer peripheral portion of a semiconductor substrate in order to prevent a photosensitive agent from adhering to a substrate transfer device during substrate transfer. When the photosensitive agent is spin-coated on the substrate, the photosensitive agent layer is peeled off by previously forming an alignment mark in a photosensitive agent peeling region formed by peeling the photosensitive agent on the substrate outer peripheral region with a solvent. An alignment mark is obtained.

As another method, Japanese Patent Application Laid-Open No. 63-117421 discloses a method in which an energy beam such as an excimer laser is irradiated onto an alignment mark on a substrate to evaporate only a photosensitive agent on the alignment mark. .

[0009]

However, even if the alignment is performed by using the alignment marks formed on the outer peripheral portion of the substrate, the influence of expansion and contraction of the substrate during the manufacturing process is different in the element formation region inside the substrate. There is a high possibility that a pattern overlay error will occur. Further, since the outer peripheral portion of the substrate from which the photosensitive agent layer has been peeled is a region that is easily damaged during the transfer of the substrate, it is not preferable to form an alignment mark in the region.

When it is necessary to form a new alignment mark, that is, to replace a so-called mark, it is necessary to form a photosensitive agent layer on the outer peripheral portion of the substrate for patterning of the new alignment mark. However, at the same time, the photosensitive agent layer is also formed on the alignment marks already formed on the outer peripheral portion, so that the existing alignment marks cannot be detected by the exposure light. Therefore, in this method, after all, when exchanging marks, it is necessary to perform alignment using non-exposure light.

On the other hand, in the method of irradiating the photosensitive agent on the alignment mark with a laser beam to evaporate it, it is difficult to control the evaporated photosensitive agent so as not to scatter around the laser beam irradiation area. There is a problem that the production yield of the device is lowered by the agent.

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned problems of the prior art, and has as its object the purpose of making it possible to set any position on a substrate without removing a photosensitive agent. It is an object of the present invention to provide a photosensitive agent coating method capable of forming an area having no size to which a photosensitive agent is not applied. Another object of the present invention is to provide a photosensitive agent coating apparatus which can form a region where a photosensitive agent is not applied at an arbitrary position and size on a substrate without removing the photosensitive agent.

Still another object of the present invention is to provide an alignment method capable of directly detecting an alignment mark through a projection optical system of a projection exposure apparatus using exposure light.

[0014]

An object of the present invention is to provide a method of applying a photosensitive agent onto a substrate while rotating the substrate, wherein the center of rotation of the substrate and the center of discharge of the photosensitive agent are shifted by a predetermined amount. This is achieved by a method of applying a photosensitive agent, which comprises applying a photosensitive agent to form a region where the photosensitive agent is not applied near the center of rotation of the substrate.

[0015] Further, the object is to apply a photosensitive agent onto a substrate by rotating a substrate having an alignment mark around a position where the alignment mark is formed, and discharging the photosensitive agent from a position shifted by a predetermined amount from the center of rotation. This is achieved by a method for applying a photosensitive agent. Further, the above object is achieved by the above-mentioned photosensitive agent applying method, wherein the rotation center of the substrate is shifted by a predetermined amount from the center position of the substrate.

Still another object of the present invention is to provide a rotary stage capable of holding and rotating a substrate, a stage rotating means for rotating the rotary stage, and discharging a photosensitive agent onto a rotating substrate positioned above the rotary stage. The present invention is attained by a photosensitive agent applying apparatus, comprising: a photosensitive agent discharge port for performing the process; and a photosensitive agent discharge port moving unit that shifts the center of rotation of the substrate and the position of the photosensitive agent discharge port by a predetermined amount.

Further, the above object is achieved by rotating a substrate having an alignment mark around a position where the alignment mark is formed, and discharging the photosensitive agent from a position shifted by a predetermined amount from the rotation center to apply the photosensitive agent onto the substrate. This is achieved by a positioning method in which a region where a photosensitive agent is not applied is formed on an alignment mark, and the exposure position is aligned using the alignment mark where the photosensitive agent has not been applied. Further, the above object is achieved by the alignment method, wherein the alignment mark is detected by a light beam having the same wavelength as an exposure light beam for exposing the substrate.

According to the present invention, the photosensitive agent is diffused and applied on the substrate by using the centrifugal force by rotating the substrate, but the photosensitive agent discharge port is positioned at an arbitrary distance from the rotation center of the substrate. Therefore, the photosensitive agent is not applied in the direction of the center of rotation due to centrifugal force. Furthermore, if the rotation center of the substrate is moved to an arbitrary position on the substrate, a region where the photosensitive agent is not applied can be formed at an arbitrary position on the substrate.

Further, if the position of the alignment mark on the substrate is set at the center of rotation, a region where the photosensitive agent layer is not formed on the alignment mark can be formed without peeling the photosensitive agent, so that the light source and the projection optical system of the projection exposure apparatus can be formed. The alignment of the alignment mark between the substrate and the reticle can be directly performed using only the system.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method and an apparatus for applying a photosensitive agent according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a surface of a semiconductor substrate (semiconductor wafer) W on which a resist is applied by the photosensitive agent applying method of the present embodiment. A resist layer 2 is formed on the entire surface except the region 1 on the wafer W. The region 1 where the resist layer 2 is not formed is formed in a circular shape including the center WCT of the wafer W as a center.

The area 1 shown in FIG. 1 is formed by the photosensitive agent coating device shown in FIG. FIG. 2 is a side view showing a state where a resist is applied onto wafer W by the photosensitive agent applying apparatus according to the present embodiment. The wafer W is mounted on a rotatable rotary stage 4 while holding the wafer by vacuum suction. The rotating shaft 6 fixed to the center of rotation of the rotating stage 4 is driven and rotated by the stage rotating mechanism 12 to rotate the rotating stage 4. Under the control of the stage rotation mechanism 12, the rotation stage 4 can rotate while changing the number of rotations arbitrarily. The wafer W is placed above the stage surface of the rotary stage 4 on which the wafer W is mounted.
A resist discharge port 8 for discharging the resist 10 is located on the surface of the substrate. The resist discharge port 8 is a discharge port position control unit 14.
Accordingly, the rotary stage 4 can be moved to an arbitrary position in the stage plane in parallel with the stage surface.

A method of forming the region 1 by using the photosensitive agent coating device will be described below. Since the resist layer 2 needs to be coated with a predetermined film thickness as uniformly as possible in order to suppress the variation in the pattern line width generated at the time of exposure, the rotary stage 4 to which the wafer W is vacuum-sucked rotates at a high speed around the rotary shaft 6. Let me do. The center WCT of the wafer W substantially coincides with the center of rotation of the rotary stage 4. Resist outlet 8
Is positioned at a position shifted by a predetermined amount from the rotation center of the rotary stage 4 by the discharge port position control unit 14.

In this state, the wafer W
When the resist 10 is discharged, the resist 10 flows on the wafer W in the outer peripheral direction of the wafer W due to centrifugal force, but does not flow in the direction of the rotation center.
A region 1 where the resist 10 is not applied (that is, the resist layer 2 is not formed) is formed near T.

By changing the position of the resist discharge port 8 and discharging the resist 10, the size of the region 1 on which the resist 10 is not applied can be arbitrarily changed. The size of the region 1 formed in the element formation region depends on the precise position control of the resist discharge port 8, the rotation speed of the rotary stage 4 of the photosensitive agent coating device, and the discharge speed of the resist 10 discharged from the resist discharge roller 8. By strictly setting conditions such as the above, it is possible to make the element formation region a predetermined size without unduly narrowing. Also, the discharged resist 10 can be prevented from being scattered in the region 1 by strictly setting conditions such as the rotation speed of the rotary stage 4 and the discharge speed of the resist 10.

Next, a method of applying a photosensitive agent according to a second embodiment of the present invention will be described with reference to FIG. In the above-described first embodiment, the center WCT of the wafer W at the time of spin coating is set to coincide with the center of rotation of the rotary shaft 6.
Is always formed at the center of the substrate including the wafer center WCT. The central portion of the wafer W is a region that is less affected by substrate distortion and the like that may occur during the process and is excellent in terms of the yield and performance of semiconductor devices. Is better to avoid. Therefore, in the present embodiment, the center of rotation of the wafer W and the center WCT of the wafer W are shifted by a required amount so that the region 1 can be formed at an arbitrary position on the wafer W, particularly at the peripheral portion of the wafer W. FIG. 3 shows the surface of the wafer W formed according to the present embodiment. As shown in FIG.
Represents the device formation region 16 of the wafer W from the wafer center WCT.
The region 1 is shifted to a position adjacent to the outer edge, and a region 1 where no resist is formed is formed around the rotation center 18 of the wafer W. If the region 1 is formed at this position, the original element formation region is not narrowed, and the wafer W can be used effectively.

The photosensitive agent coating method according to the present embodiment uses the wafer W such that the rotation center 18 of the wafer W is positioned on the rotation shaft 6 which is the rotation center of the rotary stage 4 of the photosensitive agent coating apparatus shown in FIG. Is placed on the rotary stage 4 and the first
The resist 10 is applied in the same manner as in the first embodiment. The formation position of the region 1 is set so as not to be too close to the peripheral end of the wafer W so as not to be adversely affected in the manufacturing process.

The center WCT of the wafer W and the center of rotation 1
Due to the imbalance caused by the displacement of the rotation stage 8, the rotation shaft 6 of the rotation stage 4, which holds the wafer W and rotates at a high speed, may bend and the resist 10 may not be uniformly applied. In this case, a dummy weight is placed on the rotating stage 4 or a dummy surface 20 having the same height and mass distribution as the wafer W is provided on the surface of the rotating stage 4 as shown in FIG. The resist layer 2 having a uniform thickness may be formed by eliminating the imbalance due to the shift of the rotation center.

In this manner, the wafer W having the region 1 where the resist layer 2 is not formed at an arbitrary position and size of the wafer W can be formed. Using the photosensitive agent applying method and apparatus according to the first and second embodiments using the region of the alignment mark formed in advance on the wafer W as the center of rotation, the region 1 where the resist is not applied is formed at the position of the alignment mark. can do.

Next, as a third embodiment of the present invention,
A method for aligning the wafer W using the wafer W in which the region 1 is formed at the alignment mark forming position of the wafer will be described. First, an alignment mark of the wafer W used in the alignment method according to the present embodiment will be described with reference to FIG.

As shown in FIG. 5A, the alignment mark 40 located in the region 1 where the resist layer 2 is not formed
Are provided so that correction parameters such as rotation, expansion and contraction of the wafer W can be obtained. FIG. 5A shows a case where four alignment marks 40a to 40d are formed. The number of marks may be further increased to obtain high alignment accuracy. In addition, it is possible to measure rotation, expansion and contraction, etc. with high accuracy if the distance between marks is far apart,
Since the area of the region 1 becomes large, the length between the marks is determined in consideration of the balance with the element region of the wafer W.

Further, the formed alignment mark is destroyed during the process, or a new alignment mark needs to be formed, so that it is necessary to replace the alignment mark. FIG. 5 (b)
5 shows an example of replacing the alignment mark, in which a new mark 42 is exposed on the resist layer 2 near the outer peripheral portion of the region 1 in FIG. The replacement mark formation position is accurately determined in consideration of the possibility that the thickness of the end portion of the resist layer 2 in contact with the region 1 may be non-uniform. FIG.
As shown in FIG. 2B, in the exposure for exchanging the mark, the position of the rotation center 18 of the wafer W is not changed, and the position of the resist discharge port 8 is further moved away from the rotation center 18 by a predetermined amount. The region 44 where the resist is not applied is formed by using the photosensitive agent application method according to the present invention. According to the method,
Since the replacement area of the alignment mark is sequentially enlarged, an area for replacing the mark is secured in advance.

In the case where the area 1 is formed at the position shown in FIG. 3, the remaining three corners adjacent to the outer edge of the element forming area 16 are sequentially used as mark replacement areas. If this is the case, the area outside the element formation region of the wafer W can be effectively used, which is economical. Further, as shown in FIG. 6, the peripheral portion 46 of the wafer W from which the resist layer 2 has been peeled off.
Alignment marks are formed in both the region 1 and the region 1 in the first embodiment, so that a correction parameter for the peripheral portion of the wafer W and a correction parameter for the central portion can be obtained, thereby achieving high-precision alignment. It is also possible to do. Also, in combination with the conventional method, the region 1 according to the present embodiment may be formed only when a layer requiring high alignment accuracy is formed, and the frequency of mark replacement may be reduced.

Next, an alignment method according to a fourth embodiment of the present invention will be described. A schematic configuration of a projection exposure apparatus used in the present embodiment will be described with reference to FIG. Reticle R
Is held on a reticle stage (not shown) that can move the reticle R in the X, Y and rotational directions. Alignment mark 2 on the lower surface of reticle R together with the circuit pattern
2, 24 are formed. Exposure light IL irradiates the reticle R from a light source (not shown) above the reticle R. The exposure light IL is ultraviolet light, and for example, an excimer laser, a high-pressure mercury lamp, or the like is used as an exposure light source. A reticle microscope 26 between the light source and the reticle R;
28 and a photodetector 30 are arranged, and the illumination optical system (not shown) illuminates the reticle R with uniform illuminance under predetermined illumination conditions while the alignment marks 22 and 24 of the reticle R are arranged.
Can be observed. Some illumination optical systems can change the numerical aperture (NA) of illumination light of the reticle R by changing illumination conditions. Also, since FIG. 7 shows the stage of alignment, a blind 32 for opening only a predetermined position is inserted between the light source and the reticle R.

The projection optical system PL is arranged on the lower surface side of the reticle R. At the time of exposure, the exposure light IL illuminates the reticle R on which the circuit pattern is drawn, and the light beam that has passed through the reticle R is adsorbed on the wafer stage WST via the projection optical system PL to form an image on the wafer W mounted thereon. The pattern of the reticle R is transferred. The exposure method includes reticle R
And a method of exposing while the wafer W is kept stationary, and a method of exposing while relatively moving the reticle R and the wafer W.

The wafer W used in this embodiment has a region 1 in which no resist layer is formed on the alignment mark, similarly to the wafer in the above-described third embodiment. A plurality of chips are formed on the wafer W mounted on the wafer stage WST.
The ST performs an exposure operation on each chip while sequentially moving. At that time, the wafer stage WST is accurately positioned by the reflecting mirror 34 and the laser interferometer 36. On wafer stage WST, reference plate 38 used for positioning reticle R is also provided.

Now, an alignment method according to the present embodiment using this projection exposure apparatus will be described below. First, the wafer stage WST is moved to move the reference plate 38 to the projection optical system P.
L. Although not shown, a reference mark is formed on the reference plate 38. Exposure light IL to reticle R
Then, the light is irradiated onto the reference mark of the reference plate 38 through the projection optical system PL, and the reflected light is observed by the reticle microscope 26.
Fine adjustment of the reticle stage (not shown)
Reticle R is aligned with reference plate 38 such that upper alignment mark 22 and reference mark of reference plate 38 on wafer stage WST overlap.

Next, wafer stage WST is moved to position wafer W below projection optical system PL. The blind 32 is used so as to illuminate only a region to be observed by the reticle microscope 26 so that the resist layer 2 on the wafer W is not exposed by the exposure light IL during the detection of the alignment mark on the wafer W. Reticle R and projection optical system PL
The wafer W is finely moved so that the alignment mark 40 formed on the wafer W is overlapped with the alignment mark 22 of the reticle R by irradiating the exposure light IL onto the wafer W through the reticle microscope 26. Align. Since the resist layer 2 is not formed on the alignment mark 40 on the wafer W, the exposure light IL is not absorbed by the resist.

The alignment mark 22 of the reticle R and the alignment mark 40 of the wafer W are simultaneously enlarged by the reticle microscope 26 and imaged on a light detecting device 30 such as a CCD. If the position where both marks overlap is measured by the laser interferometer 36, the position of the wafer W with reference to the alignment mark of the reticle R can be known. From these values, values such as the X and Y positions of the wafer W, rotation, magnification error, and orthogonality error of the array are obtained, and exposure is sequentially performed based on the values. In this way, highly accurate positioning can be performed without being affected by the device stability such as the position stability of the reticle microscope 26 or the position stability of the reticle R.

In this positioning method, since the reticle R and the wafer W can be directly observed, there is no need to accurately detect the position coordinates in the X and Y directions as long as the position of the reticle R in the rotation direction is adjusted. Alternatively, the reticle may be directly aligned with reference to the alignment mark on the wafer W. In that case, the reference plate 38 may not be used.

For comparison, a conventional alignment method will be briefly described. Conventionally, a microscope for wafer observation has a projection optical system P
As an optical system different from L, for example, a microscope 50 is provided. The microscope 50 is located at the side of the projection optical system in FIG. 7 and is indicated by a broken line. The position of the microscope 50 and the position of the alignment mark of the reticle R are measured and stored in advance using the reference mark of the reference plate 38 as a reference. For example, a microscope reference mark on the reference plate 38 is detected by the microscope 50, and at the same time, the reticle reference marks on the reference plate 38 and the reticle alignment marks 22 and 24 are overlapped and detected by the reticle microscopes 26 and 28. Next, the wafer stage is moved to a predetermined position, the position of the alignment mark on the wafer W is observed by the microscope 50, and the position is determined by the interferometer 36.
Measure with

In the positioning method based on the so-called off-axis measurement, the positions of the reticle R and the wafer W cannot be superimposed at the same time and directly observed, but the positions must be obtained by observing with different microscopes. For this reason, if the projection exposure apparatus does not have sufficient stability, for example, the position stability of the microscope 50 and the position stability of the reticle R, an error occurs in the position measurement, and the positioning accuracy decreases. Would.

As described above, according to the photosensitive agent applying method and apparatus and the alignment method of the embodiment of the present invention, the alignment marks on the reticle R and the wafer W are exposed to the exposure light IL.
Therefore, the detection accuracy can be directly detected via the projection optical system PL, so that the alignment accuracy between the reticle R and the wafer W can be improved.

[0043]

As described above, according to the present invention, it is possible to extremely easily form a region where a photosensitive agent is not applied on a substrate. Further, by moving the rotation center of the substrate to an arbitrary position on the substrate, it is possible to form an area where the photosensitive agent is not applied on an arbitrary portion of the substrate.

Further, according to the present invention, a region where a photosensitive agent layer is not formed is formed on an alignment mark, and direct alignment between a substrate and a reticle can be accurately performed using only a light source and a projection optical system of a projection exposure apparatus. Will be able to do it.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for applying a photosensitive agent according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method and an apparatus for applying a photosensitive agent according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a photosensitive agent coating method according to a second embodiment of the present invention.

FIG. 4 is a view for explaining a photosensitive agent applying method according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating an arrangement of alignment marks according to a third embodiment of the present invention.

FIG. 6 is a diagram illustrating a photosensitive agent application method according to a third embodiment of the present invention.

FIG. 7 is a diagram illustrating a configuration of a projection exposure apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 area where resist layer is not formed 2 resist layer 4 rotation stage 6 rotation axis 8 resist discharge roller 10 resist 12 stage rotation mechanism unit 14 discharge port position control unit 16 element formation area 18 wafer rotation center 20 dummy surface 22, 24 alignment mark 26, 28 Reticle microscope 30 Photodetector 32 Blind 34 Reflector 36 Laser interferometer 38 Reference plate 40, 42 Alignment mark 44 Area where resist layer is not formed 46 Peripheral part of wafer 50 Microscope R Reticle W Wafer IL Exposure light PL Projection optics system

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01L 21/30 564C

Claims (6)

[Claims] 1. A photosensitive agent applying method for applying a photosensitive agent onto a substrate while rotating the substrate, wherein the photosensitive agent is applied by shifting a rotation center of the substrate and a discharge center of the photosensitive agent by a predetermined amount. Forming a region where the photosensitive agent is not applied near the rotation center of the substrate. 2. A substrate having an alignment mark is rotated about a position at which the alignment mark is formed, and a photosensitive agent is discharged from a position shifted by a predetermined amount from the rotation center to apply the photosensitive agent on the substrate. A method for applying a photosensitive agent, comprising: 3. The method according to claim 1, wherein the center of rotation of the substrate is shifted from the center of the substrate by a predetermined amount. 4. A rotating stage which can hold and rotate a substrate, a stage rotating means for rotating the rotating stage, and a photosensitive member which is located on the rotating stage and discharges a photosensitive agent onto the rotating substrate. A photosensitive-agent applying apparatus, comprising: an agent-discharging port; and a photosensitive-agent-discharging-port moving unit configured to shift a rotation center of the substrate and the position of the photosensitive-agent discharging port by a predetermined amount. 5. A substrate having an alignment mark is rotated about a position at which the alignment mark is formed as a rotation center, and a photosensitive agent is discharged from a position shifted by a predetermined amount from the rotation center to apply the photosensitive agent on the substrate. Forming an area where the photosensitive agent is not applied on the alignment mark, and performing exposure alignment using the alignment mark where the photosensitive agent is not applied. 6. The alignment method according to claim 5, wherein said alignment mark is detected by a light beam having the same wavelength as an exposure light beam for exposing said substrate.