JP2000082649A - Method and device for projection alignment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for projection alignment by which the image forming characteristic of a projection optical system can be prevented without lowering the throughput of exposure treatment nor giving any unnecessary energy to the optical system and/or a mask. SOLUTION: In a projection alignment method, the surface of a wafer W is exposed to light by a plurality of shots by repeating the illumination of a reticle R on which two or more reticle patterns are formed correspondingly to two or more adjacent first areas 201 and the formation of the images of the two or more reticle patterns formed on the reticle R on the surface of the wafer W through a projection optical system by setting the two or more first areas 201 as one-shot area in order to form a plurality of first areas 201 having the same pattern on the surface of the wafer W. At the time of performing the exposure in a specific shot in which the transfer of all of the two or more reticle patterns on the reticle R to the surface of the wafer W is not required, the formation of the images (203-209) of the reticle patterns which are not required to be transferred to the wafer W of the reticle patterns formed on the reticle R is limited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure method and a projection exposure apparatus used for exposure when, for example, a semiconductor device, a liquid crystal display, and other microdevices are manufactured by a photolithography process. TECHNICAL FIELD The present invention relates to a projection exposure method and a projection exposure apparatus which are preferably used at the time of superposition exposure in which different exposure areas of one shot are exposed to different layers of the same substrate.

[0002]

2. Description of the Related Art In recent years, in semiconductor devices and the like, the line width of a gate electrode and the like formed on a substrate (such as a semiconductor wafer) has become finer, and the exposure wavelength has tended to be shortened so as to be able to cope with this. is there. However, with the shortening of the wavelength, the light source for exposure has shifted from a mercury lamp to an excimer laser, and has become more expensive. Accordingly, the glass material of the projection optical system of the exposure apparatus is limited, and an optical member made of quartz or the like, which is more expensive, is used. In this respect, the price of the exposure apparatus is becoming higher. Therefore, an exposure method has been proposed in which a fine pattern of all functional thin film layers formed on the surface of a substrate is not exposed by a critical layer exposure apparatus capable of exposing a pattern having the finest line width. In this exposure method, of the fine patterns of all the functional thin film layers formed on the surface of the substrate, the pattern formed on the functional thin film layer on which a pattern with a larger line width is to be formed is converted into an inexpensive rough layer having relatively low resolution. Exposure with an exposure device,
Use of critical layer exposure equipment is minimized. Furthermore, for a functional thin film layer on which a pattern with a larger line width is to be formed, the resolution is not so required.
In the rough layer exposure apparatus, an exposure area several times larger than the one-shot exposure area of the critical layer exposure apparatus is exposed with one shot. This improves the processing capacity (throughput) per unit time.

In a rough layer exposure apparatus, an inexpensive mercury lamp (i-line, g-line, etc.) is generally used as an exposure light source. Unlike an excimer laser exposure apparatus (critical layer exposure apparatus), a projection optical system of an exposure apparatus using these as an exposure light source does not use quartz glass excellent in transmittance, but uses general optical glass. The reason is that quartz glass is expensive, and a plurality of glass materials are required for correcting chromatic aberration of quartz glass for a wide spectral width of a mercury lamp. Further, in an excimer laser exposure apparatus, a photosensitive agent having a high sensitivity such as a chemically amplified resist can be used, but it is not used in a mercury lamp exposure apparatus because it is expensive.

[0004]

For this reason, in a rough layer exposure apparatus such as a mercury lamp exposure apparatus, the energy of the exposure illumination light is absorbed and the temperature of the projection optical system changes.
There is a problem that the imaging characteristics are deteriorated.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 63-291417, there has been proposed an exposure apparatus in which a function of providing a wait for the exposure operation is added to the projection optical system so that a certain amount of energy does not enter the projection optical system. Have been. This technique is effective for imaging characteristics that are relatively easy to correct, such as the focal position and magnification, but is also effective for changes that are more difficult to correct, such as distortion and curvature of field. . Further, even in the image forming characteristics that can be corrected, if the correction amount increases, there is a side effect that the stroke of the correction system becomes insufficient, or the image forming performance that is not the purpose is changed. . Even in the rough layer exposure apparatus, it is necessary to avoid fluctuations in exposure performance such that the energy of the exposure illumination light is absorbed, the temperature of the projection optical system changes, and its imaging characteristics deteriorate.

In addition, not only does the projection optical system absorb the exposure illumination light, but also the light shielding portion of the exposure mask absorbs the exposure illumination light and is deformed. There has been proposed an exposure apparatus having a function of waiting for an exposure operation so that a mask does not absorb more than a certain amount of energy. However, such a method of controlling the energy of the exposure illumination light by controlling the exposure operation has a problem that the productivity (throughput) of the exposure apparatus must be sacrificed.

When performing exposure using a rough layer exposure apparatus at the time of superposition exposure in which different exposure areas of one shot are exposed to different layers of the same substrate,
An exposure area several times larger than the one-shot exposure area of the critical layer exposure apparatus is exposed with one shot. As a result, the processing capacity (throughput) per unit time can be improved.

However, when performing exposure using such a rough layer exposure apparatus, for example, when one shot is exposed on the outer peripheral portion of the substrate, a part of the exposed region may protrude outside the substrate. In such a case, extra exposure illumination light is incident on the mask and the projection optical system in order to expose a portion that is not originally required, causing a rise in the temperature of the illumination light and causing an unnecessary change in the imaging characteristics. Would.

The present invention has been made in view of such circumstances, and does not reduce the throughput of the exposure processing, and does not apply unnecessary energy to the projection optical system and / or the mask, thereby preventing the deterioration of the imaging characteristics. It is an object of the present invention to provide a projection exposure method and a projection exposure apparatus which can perform the above.

[0010]

In the following description, the present invention will be described with reference to the member codes shown in the drawings showing the embodiments. However, the present invention is not limited to the members shown in the drawings attached with.

A projection exposure method according to a first aspect of the present invention (corresponding to claim 1) is for forming a plurality of first regions (201, 301) of the same pattern on the surface of a photosensitive substrate (W). In addition, two or more adjacent first regions (201, 30)
With 1) as one shot area (202, 302), a mask (R) on which two or more mask patterns corresponding to the two or more adjacent first areas (201, 301) are formed is illuminated, and the mask (R) is illuminated. R) forming images of the two or more mask patterns formed on the photosensitive substrate (W) through the projection optical system (PL) on the surface of the photosensitive substrate (W) repeatedly. A projection exposure method for exposing a plurality of shots to the photosensitive substrate (W), wherein all of two or more mask patterns on the mask (R) among the plurality of shots need to be transferred onto the photosensitive substrate (W). When exposing a specific shot, a mask pattern that does not need to be transferred onto the photosensitive substrate (W) among the mask patterns on the mask (R) is restricted from being formed. I do.

At the time of exposing the specific shot, an image of a mask pattern which does not need to be transferred onto the photosensitive substrate (W) out of the two or more mask patterns is formed on the outside of the photosensitive substrate (W). It is preferable to limit what is done (corresponding to claim 3).

In order to limit the formation of an image of a mask pattern which does not need to be transferred onto the photosensitive substrate (W) among the mask patterns on the mask (R) during the exposure of the specific shot. Preferably, part of the exposure illumination light for illuminating the mask (R) is shielded (corresponding to claim 5).

A projection exposure method according to a second aspect of the present invention (corresponding to claim 2) provides a single first region (201, 30).
1) is defined as one shot area, and the first area (201, 3)
01) on which a first mask pattern corresponding to (01) is formed.
Illuminating the mask (R) to form an image of the first mask pattern formed on the first mask (R) on the surface of the photosensitive substrate (W) via the projection optical system (PL). A first projection exposure for repeatedly exposing a plurality of shots to the surface of the photosensitive substrate (W), and two or more first areas (201, 301) adjacent to one shot area (202, 30).
2) and the adjacent two or more first regions (201, 3)
01), the second mask (R) on which two or more second mask patterns corresponding to the second mask (R) are formed, and the second mask (R) is illuminated.
The images of the two or more second mask patterns formed on the surface of the photosensitive substrate (W) are repeatedly formed through the projection optical system (PL) on the surface of the photosensitive substrate (W). A second projection exposure for exposing a plurality of shots to different layers of the same photosensitive substrate (W), and performing the second projection exposure for the photosensitive substrate (W) a plurality of shots. When exposing a specific shot that does not require transfer of all of the two or more second mask patterns on the mask (R) onto the photosensitive substrate (W), two or more on the second mask (R) The image forming apparatus is characterized in that the formation of an image of the second mask pattern, which does not need to be transferred onto the photosensitive substrate (W), is restricted.

[0015] The first projection exposure and the second projection exposure may be performed using the same exposure apparatus or may be performed using different exposure apparatuses. When the exposure is performed using another exposure apparatus, the first projection exposure can be performed using a critical layer exposure apparatus, and the second projection exposure can be performed using a rough layer exposure apparatus. The exposure of the one-shot regions having different areas is performed on the same photosensitive substrate (W).
Performing on different layers is referred to as overlay exposure.

At the time of exposing the specific shot, an image of the second mask pattern, which does not need to be transferred onto the photosensitive substrate (W), of the two or more second mask patterns is formed on the photosensitive substrate (W). It is preferable to limit the image formation to the outside (corresponding to claim 4).

At the time of exposing the specific shot, the second
In order to limit the formation of an image of the second mask pattern that does not need to be transferred onto the photosensitive substrate (W) among the second mask patterns on the mask (R), the second mask ( It is preferable that part of the exposure illumination light for illuminating R) be shielded (corresponding to claim 6).

A projection exposure apparatus according to the present invention (corresponding to claim 7) is a method for forming two or more first regions (201, 301) of a predetermined pattern on the surface of a photosensitive substrate (W) in one shot. A mask stage (9) for holding a mask (R) on which the above mask pattern is formed, an illumination optical system for illuminating the mask (R), and the mask (R)
A projection optical system (PL) for forming images of two or more mask patterns formed on the surface of the photosensitive substrate (W) via a projection optical system (PL); When exposing a specific shot that does not require transferring all of the two or more mask patterns onto the photosensitive substrate (W), the mask pattern on the photosensitive substrate (W) is exposed on the mask (R). And a specific shot restricting mechanism (4, 8) for restricting formation of an image of a mask pattern that does not need to be transferred to a specific shot.

The specific shot limiting mechanism (4, 8)
Are light-shielding mechanisms for specific shots (4, 8) for shielding a part of the exposure illumination light for illuminating the mask (R). Is provided separately from the normal light-shielding mechanism (3), which does not change, and has a lower positional accuracy than the normal light-shielding mechanism (3).
It is preferable that the light shielding operation is fast (corresponding to claim 8).

The specific shot light blocking mechanism (4, 8)
Is preferably disposed near a plane optically conjugate with the mask (R) (corresponding to claim 9).

The specific shot light shielding mechanism (4, 8)
May be supported by the mask stage (9) (corresponding to claim 10).

In the present invention, the projection exposure apparatus includes:
The g-line (436 nm) and the i-line (365n) are not particularly limited.
m), KrF excimer laser (248 nm), ArF excimer laser (193nm), _{F 2} laser (157N
m) or an exposure apparatus using a harmonic such as a YAG laser as an exposure light source, but also includes an X-ray exposure apparatus and an electron beam (EB) exposure apparatus.

The type of exposure apparatus according to the type of exposure method is not particularly limited, and may be a so-called step-and-repeat type exposure apparatus or a so-called step-and-scan type exposure apparatus. A so-called step-and-scan exposure apparatus exposes a part of a pattern on a mask (R) such as a reticle to a projection optical system (PL).
The mask (R) and the photosensitive substrate (W) are synchronously moved with respect to the projection optical system (PL) in a state where the reduced projection exposure is performed on the photosensitive substrate (W) through the mask (R). ) Is an exposure apparatus of a method of sequentially transferring a reduced image of the pattern above to each shot area of the photosensitive substrate (W). The exposure apparatus of this type has an advantage that the pattern to be transferred can be enlarged without increasing the load on the projection optical system (PL) as compared with the exposure apparatus of the so-called step-and-repeat type. is there.

[0024]

In the projection exposure method and the projection exposure apparatus according to the present invention, since two or more adjacent first areas (201, 301) are used as one shot area (202, 302), a single first exposure is performed. Compared with the method of performing projection exposure using only the areas (201, 301) as one shot area, the processing capability (throughput) per unit time can be improved.

Further, the two or more adjacent first areas (201, 301) are divided into one shot areas (202, 30).
When performing the projection exposure as 2), for example, the substrate (W)
1 shot area (202, 30
In some cases, part of 2) protrudes outside the substrate (W). In such a case, conventionally, in order to expose a portion that is not originally required, extra exposure illumination light is incident on the mask (R) and the projection optical system (PL), which causes a rise in the temperature of the illumination light. As described above, the imaging characteristics are changed.

However, in the projection exposure method and projection exposure apparatus according to the present invention, it is not necessary to transfer all of two or more mask patterns on the mask (R) onto the photosensitive substrate (W). At the time of exposing a specific shot, an image of a mask pattern which does not need to be transferred onto the photosensitive substrate (W) among the mask patterns on the mask (R) is restricted from being formed. For this reason, in the present invention, when exposing a specific shot, a part of the exposure illumination light that is originally wasted is restricted from reaching the mask (R) and / or the projection optical system (PL). As a result, it is possible to prevent deterioration of the imaging performance caused by absorption of the illumination light for exposure to the mask (R) and / or the projection optical system (PL).

In the projection exposure method and the projection exposure apparatus according to the present invention, unlike the technique disclosed in JP-A-63-291417, this is not a method for controlling the energy of the exposure illumination light by controlling the exposure operation. Therefore, the productivity (throughput) of the exposure apparatus is not sacrificed in exchange for the imaging characteristics.

In the exposure of a specific shot, an image of the second mask pattern that does not need to be transferred onto the photosensitive substrate (W) among the two or more second mask patterns is originally wastefully used. Therefore, it is not always necessary to shield all the wasteful portions with high accuracy, and it is sufficient that at least a part of the wasteful portions is shielded. From such a viewpoint, in the projection exposure apparatus according to the present invention, it is preferable that the specific shot light shielding mechanism (4, 8) is provided separately from the normal light shielding mechanism (3) which does not change for each shot. . Generally, the light shielding mechanism (3) generally includes a mask (R).
Is used for sequence control for repeatedly exposing only a part of the pattern, and the driving speed is not high instead of the accurate position accuracy on the mask (R). Therefore, when the normal light shielding mechanism (3) is operated for each shot to irradiate only the necessary portion of the mask (R) and / or the projection optical system (PL) with the illumination light for exposure, the normal light shielding mechanism (3) is used. Since the driving speed of 3) is low, the throughput is significantly deteriorated. In the present invention, the light-shielding mechanism for specific shots (4, 8) is provided separately from the normal light-shielding mechanism (3) that does not change for each shot.
Does not require high-precision position control for the reasons described above. Therefore, in the present invention, it is possible to use a light-shielding mechanism for specific shots (4, 8) that has a low position control accuracy but a fast light-shielding operation, and improves throughput.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. FIG. 1 is a schematic view of a projection exposure apparatus according to an embodiment of the present invention, FIGS. 2 and 3 are explanatory views showing the relationship between a one-shot area and a wafer, and FIGS. FIG.

First Embodiment A projection exposure apparatus 10 according to this embodiment shown in FIG. 1 is a rough layer exposure apparatus, and a mercury lamp is used as a light source 1. The projection exposure apparatus 10 may be an excimer laser exposure apparatus used as a current critical layer exposure apparatus.

The exposure light beam from the light source 1 is
Accordingly, illumination light for exposure is made uniform, and the reticle R as a mask is illuminated under predetermined illumination conditions. In FIG. 1, the illumination light emitted from the illumination optical system 2 illuminates a normal light shielding mechanism 3 arranged on a surface optically conjugate with the reticle R. Normally, the light shielding mechanism 3 is used for exposing only a part of the surface of the reticle R. However, the surface of the light-shielding mechanism 3 is not completely conjugate with the surface of the reticle R without any aberration, and a certain degree of blurring occurs on the reticle R. In addition, since the positioning accuracy of the light-shielding mechanism 3 usually causes an error, a light-shielding portion having a certain width is drawn on the reticle R, and the reticle R is used so that an image of the edge of the light-shielding mechanism 3 comes inside. . If the light-shielding portion on the reticle is widened, the reticle surface cannot be used effectively when a plurality of areas are provided on one reticle and the exposure is performed separately. Must be within a certain range.

Normally, the illuminating light passing through the light shielding mechanism 3 passes through the relay optical system 5 and the reflecting mirror 6, and illuminates the reticle R. The reticle R is held by being attracted to the reticle stage 9. The illumination light that has passed through the reticle R forms an image of a pattern on a silicon wafer W as a photosensitive substrate coated with a photosensitive agent (resist) via a projection optical system PL. The wafer W is held by a wafer stage WST, and performs an exposure operation while moving the wafer W. In the present embodiment, the exposure operation is performed by a so-called step-and-repeat method.

A photoelectric sensor (not shown) is provided on wafer stage WST, and can measure the energy amount of exposure illumination light passing through projection optical system PL. The energy stored in the projection optical system PL or the reticle R is calculated based on the value of the energy amount detected by the photoelectric sensor and the shutter information of the mercury lamp or the light emission information of the laser to correct the fluctuation of the imaging characteristics. It has become. Further, based on the value of the energy amount detected by the photoelectric sensor, when it is determined that the accumulated energy amount exceeds a certain value, the exposure operation is stopped, and control is performed so that no more energy is accumulated. You can also.

In the projection exposure apparatus 10 according to this embodiment,
As shown in FIG. 1, a specific-shot light-shielding mechanism 4 is mounted immediately near the normal light-shielding mechanism 3. The specific shot light shielding mechanism 4 is displaced from the surface of the normal light shielding mechanism 3 located on the reticle conjugate plane.
Larger than. However, the specific shot light shielding mechanism 4
Is driven by a motor having a larger output than the normal light shielding mechanism 3, and its driving speed is faster. In addition, the specific-shot light shielding mechanism 4 does not require a high degree of stillness as compared with the normal light shielding mechanism 3, and thus has a feature of operating quickly and stopping quickly.

In the present embodiment, it is necessary to operate the wafer stage WST in a very short time (normally 1 second or less) while moving to the next one shot area, but the accuracy of the stop position is not so required. This is because, in order to limit the formation of an image of a reticle pattern that does not need to be transferred onto the wafer W among the reticle patterns on the reticle R, and to block a part of the illumination light to the reticle R, This is because the specific shot light shielding mechanism 4 is used. That is, even if the light shielding is not complete, if the shutter of the light shielding mechanism 4 is controlled so as to stop with a margin before the area to be exposed, even if the stop control accuracy is low, it is possible to expose the unnecessary unnecessary area to the exposure area. This is because there is no actual harm because only the illumination light arrives, and most of the unnecessary illumination light can be shielded by the light shielding mechanism 4.

If the ordinary light-shielding mechanism 3 which requires accuracy is required to have a higher operating speed, the light-shielding mechanism 3 becomes very expensive and is not practical. In this embodiment,
Since the specific shot light shielding mechanism 4 is mounted separately from the normal light shielding mechanism 3, an inexpensive and practical projection exposure apparatus can be realized. Of course, the present invention does not exclude giving the normal light shielding mechanism 3 the function of the specific shot light shielding mechanism.

As shown in FIG. 2, for a circular silicon wafer W, a first region 201 which is a one-shot exposure region of the critical layer exposure apparatus is indicated by hatching, and the rough region shown in FIG. Layer exposure apparatus 1
The shot exposure area 202 is indicated by a black frame. One-shot exposure area 202 of rough layer exposure apparatus 10 includes two adjacent first areas 201. On the reticle R shown in FIG. 1, two reticle patterns corresponding to the pair of first regions 201 shown in FIG. 2 are formed. That is, FIG.
The exposure apparatus 10 according to the present embodiment repeatedly forms images of two reticle patterns formed on the reticle R on the surface of the wafer W in one shot via the projection optical system PL. A large number of repetitive patterns are transferred to the entire surface of W. In the exposure apparatus 10, the entire surface of the wafer W can be exposed with about half the number of shots as compared with an exposure apparatus in which the single first region 201 is used as one shot region.

Conventionally, when such projection exposure is performed, most of the half of the one-shot exposure area 202 surrounded by a black frame is outside the wafer when a specific shot for exposing the outer peripheral portion of the wafer W is exposed. And unnecessary regions 203 to 209 in which semiconductor elements are not formed exist. Conventionally, these unnecessary regions 203 to 209 are also automatically subjected to one-shot exposure including the two first regions 201, and are exposed to illumination light for exposure. For this reason, unnecessary energy is applied to the reticle R and the projection optical system PL, and the imaging performance is deteriorated, or the throughput in exchange for it is deteriorated.

In this embodiment, as shown in FIG. 2, two reticle patterns on the reticle R (corresponding to the two first regions 201 on the wafer W) are exposed at the time of exposing a specific shot for exposing the outer peripheral portion of the wafer W. ) Is the wafer W
The control device of the exposure apparatus determines whether or not it is not necessary to transfer the image to the upper side. Then, only at the time of such a specific shot, a part of the illumination light directed to the reticle pattern on the reticle R corresponding to the unnecessary areas 203 to 209 is shown in FIG.
The light is shielded using the specific shot light shielding mechanism 4 shown in FIG.

In this embodiment, the specific shot light-shielding mechanism 4 has a light-shielding blade 401 shown in FIG. 4, and the blade 401 is arranged so as to be movable forward and backward along the X direction of the illumination area 402. , The normal light shielding mechanism 3 shown in FIG.
, About half of the illumination area 402 (which may be left or right) after passing through can be appropriately shielded. The light shielding area of the illumination area 402 which is shielded by the blade 401 corresponds to the unnecessary portions 203 to 209 shown in FIG. When it is not necessary to shield the light, the blade 401 moves backward along the X direction, and opens the entire illumination area 402.

The control device of the exposure apparatus determines whether one of the two reticle patterns on the reticle R (corresponding to the two first areas 201 on the wafer W) does not need to be transferred onto the wafer W. The controller compares the shot area that has already been exposed with the shot area to be exposed. The control device of the exposure apparatus is
Optimization is performed by determining in which arrangement one shot is repeatedly exposed on the wafer W to minimize the number of shots to be exposed in the future, and then a specific shot to be shielded is determined. Is also good.

In any case, the controller determines which half of the illumination area 402 shown in FIG. 4 should be shielded from light by the blade 401 at the time of exposure of any specific shot. During a short time when the wafer stage WST shown in FIG.
Move 1 to shield light. Until the next shot is exposed, the blade 401 is returned to the original position, and exposure using the entire illumination area 402 shown in FIG. 4 is performed.
In the case where the operation speed of the blade 401 shown in FIG. 4 controls the sequence control of the entire exposure apparatus, even if the light is not completely shielded in all the shots to be shielded, a part of the exposure time is not required. Since there is an effect even if the light is shielded, the light shielding control may be performed for a partial time. Further, the blade 4 shown in FIG.
In the case of 01, it is not necessary to shield light in exactly half of the illumination area 402, and it is effective to shield light in less than half. This is because the light-shielded portions correspond to the unnecessary portions 203 to 209 shown in FIG. 2 and are portions where no pattern is formed.

In the projection exposure method and the projection exposure apparatus 10 according to the present embodiment, as shown in FIG. 2, the projection exposure is performed using two adjacent first regions 201 as one shot region. Compared with the method of performing projection exposure using only 201 as one shot area, the processing capability (throughput) per unit time can be improved.

When projection exposure is performed using two or more adjacent first regions 201 as one shot region, a part of the one shot region, such as the outer peripheral portion of the wafer W, is partially exposed to the substrate. May protrude from the outside.
In such a case, conventionally, extra exposure illumination light is incident on the reticle R and the projection optical system PL in order to expose a portion that is not originally required, causing a rise in the temperature thereof.
The imaging characteristics are changed more than necessary.

However, in the projection exposure method and the projection exposure apparatus according to the present embodiment, when exposing a specific shot in which it is not necessary to transfer all of the two reticle patterns on the reticle R onto the wafer W, the reticle R This limits formation of an image of a reticle pattern that does not need to be transferred onto the wafer W among the reticle patterns. For this reason, in the present embodiment, at the time of exposing a specific shot, a part of the exposure illumination light that is originally wasted is restricted from reaching the reticle R and the projection optical system PL. as a result,
It is possible to prevent the deterioration of the imaging performance caused by the absorption of the illumination light for exposure to the reticle R and the projection optical system PL.

Second Embodiment As shown in FIG. 3, in the present embodiment, four circular first wafers 301, which are one-shot exposure areas of a critical layer exposure apparatus, are applied to a circular silicon wafer W. This is a one-shot exposure area 302 of the rough layer exposure apparatus 10 shown in FIG. The reticle R shown in FIG. 1 has four reticle Rs corresponding to the four first regions 301 shown in FIG.
One reticle pattern is formed. That is, the exposure apparatus 10 according to the present embodiment repeatedly forms images of four reticle patterns formed on the reticle R on the surface of the wafer W in one shot via the projection optical system PL. A large number of repetitive patterns are transferred to the entire surface of W. In this exposure apparatus 10, compared to an exposure apparatus in which a single first area 301 is used as one shot area,
The number of shots can be significantly reduced, and the throughput can be improved.

In performing such projection exposure, conventionally, when exposing a specific shot for exposing the outer peripheral portion of the wafer W, 1/4, 2/4 or 3 of the one-shot exposure area 302 surrounded by a black frame is exposed. Most of / 4 are located outside the wafer, and there are unnecessary regions 303 to 309 in which semiconductor elements are not formed. These unnecessary areas 303
Up to 309, one shot exposure including the four first regions 301 is automatically performed, and the illumination light for exposure is applied. For this reason, unnecessary energy is applied to the reticle R and the projection optical system PL, and the imaging performance is deteriorated, or the throughput in exchange for it is deteriorated.

In this embodiment, as shown in FIG. 3, at the time of exposing a specific shot for exposing the outer peripheral portion of the wafer W, four reticle patterns (4
The control device of the exposure apparatus determines whether or not it is necessary to transfer at least one of the first areas 301 (corresponding to the first areas 301) onto the wafer W. Then, only during such a specific shot, a part of the illumination light directed to the reticle pattern on the reticle R corresponding to the unnecessary areas 303 to 309 is shielded using the specific shot light shielding mechanism 4 shown in FIG. .

In this embodiment, the specific shot light-shielding mechanism 4 has a light-shielding blade 501 shown in FIG. 1 so that it can move freely forward and backward, so that one of the left, right, up, and down of the illumination area 502 after passing through the normal light shielding mechanism 3 shown in FIG.
4, 2/4 or 3/4 can be appropriately shielded from light.
The light-shielding area of the illumination area 502 which is shielded by the blade 501 and other blades corresponds to the unnecessary portion 30 shown in FIG.
3 to 309.

The blade 501 shown in FIG.
02 is a blade for transmitting only the upper right １ ／ of the illumination area 502. If the blade 501 is configured to be rotatable around the concave top angle 503 of the blade 501, the lower right の of the illumination area 502, It can also be used as a blade that transmits only the lower left quarter and the upper left quarter. In addition, the same blade as a small blade obtained by dividing the blade 501 into three along the dotted line 504 is disposed so as to be able to translate freely at each apex position of the illumination area 502, and each of the blades can operate independently. A structure in which １ ／, ／, or ／ of the left, right, top, or bottom of the illumination area 502 can be appropriately shielded.

Further, the blade 401 shown in FIG. 4 and the blade 501 shown in FIG. 5 can be used in combination. Further, by making the blade 401 shown in FIG. 4 movable in the two-dimensional direction (X and Y directions) of the illumination area 502 shown in FIG. 2/4 may have a structure that can appropriately shield light. In this case, it is not possible to cope with the case where 3/4 of the left, right, top and bottom of the illumination area 502 is shielded, but even if all of 3/4 of the illumination area 502 is not shielded, 1 / 2, the effect of the present invention can be sufficiently expected.

That is, in the present invention, even if the area to be shielded in the illumination area 502 is not necessarily completely shielded,
In addition, the effects of the present invention can be sufficiently expected without necessarily shielding with high precision. In addition, the effects of the present invention can be expected to be sufficient even when the shielding is not completely performed during one shot. From the viewpoint of improving the throughput, the blade 401 or 501 is required for a short time before the next shot.
It is necessary to drive the blade 401 or 50 quickly in the middle of one shot if it cannot follow.
1 may be moved. The other configuration, operation and effect of the present embodiment are the same as those of the first embodiment,
The description is omitted.

Other Embodiments The present invention is not limited to the above-described embodiments, and can be variously modified within the scope of the present invention.

For example, in the above-described embodiment, as shown in FIG. 1, the specific light shielding mechanism 4 is arranged near the conjugate plane with the reticle. However, the present invention is not limited to this. A specific shot light shielding mechanism 8 may be arranged on the front surface. Light shielding mechanism 8 for specific shots
The blade 4 shown in FIG.
01 and / or the blade 501 shown in FIG.

In the case where the specific shot light shielding mechanism 8 is arranged in front of the reticle R on the reticle stage 9, the distance from the pattern surface of the reticle R is large and the shadow edge due to shielding is blurred. There is no problem at all because the unnecessary portions of the exposure illumination light are avoided with a margin and the originally unnecessary portions are shielded.

In the above embodiment, the projection exposure apparatus shown in FIG. 1 has been described as a step-and-repeat type exposure apparatus, but the present invention is also applied to a so-called step-and-scan type exposure apparatus. be able to. In general, a rough layer exposure apparatus needs to be manufactured at a low cost, so that an expensive scan type is not often used. However, since the exposure area can be made large by the exposure area, it may be used. In the case of the scanning type exposure apparatus, it is relatively easy to perform only partial exposure by shifting the scan start position in the scanning direction. Originally, in the scanning type exposure apparatus, with respect to the scanning direction, the normal light shielding mechanism is configured so as to operate at high speed in synchronization with scanning so that both ends of the scanning exposure are not excessively exposed even in the normal case. It is not necessary to separately provide a light shielding mechanism. In the direction perpendicular to the scanning direction, it is necessary to provide a light shielding mechanism for a specific shot as in a step-and-repeat type exposure apparatus. In this case, the specific shot light shielding mechanism includes the blades 401 and 501 shown in FIG. 4 or FIG. 5 or other blades. Note that, similarly to the specific shot light shielding mechanism 8 shown in FIG. 1, if the light shielding mechanism is held on the reticle stage of the step-and-scan type exposure apparatus,
Since the light shielding mechanism moves synchronously with the reticle R,
A mechanism for synchronously moving the light shielding mechanism with the reticle R is not required, and the configuration of the light shielding mechanism can be simplified.

The present invention can be similarly applied to an exposure apparatus such as a mirror projection system or a proximity system. The projection optical system PL shown in FIG.
May be all optical elements may be refractive elements (lenses), may be an optical system consisting only of reflective elements (mirrors, etc.), or may consist of refractive elements and reflective elements (concave mirrors, mirrors, etc.) It may be a catadioptric optical system. Further, the projection optical system PL is not limited to the reduction optical system, but may be an equal-magnification optical system or an enlargement optical system.

Further, as a light source, EUV (Extreme Ultra) having an oscillation spectrum in a soft X-ray region is used.
The present invention is also applicable to a reduced projection type scanning exposure apparatus using a SOR that generates (Violet) or a laser plasma light source, or an X-ray scanning exposure apparatus of a proximity system.

Furthermore, in the above-described embodiment, the wafer W is used as the photosensitive substrate. However, the present invention is not limited to the wafer, and is not limited to the wafer, but may be a substrate for a liquid crystal display, a substrate for manufacturing a magnetic head, or a micro device. Substrates or other substrates can be used.

Incidentally, the exposure apparatus is generally equipped with a normal light shielding mechanism for limiting an exposure area. Therefore, it is conceivable to limit the range of the exposure illumination light incident on the mask and / or the projection optical system for each shot by using the normal light shielding mechanism. However, this normal light-shielding mechanism is used for sequence control for repeatedly exposing only a part of the pattern of the mask, and the driving speed is not high instead of accurate position accuracy on the mask. Therefore, when the normal light shielding mechanism is operated for each shot to irradiate only the necessary portion of the mask and / or the projection optical system with the exposure illumination light, the driving speed of the normal light shielding mechanism is low, so that the throughput is low. Getting worse.

The reason why the driving speed of the light-shielding mechanism is usually low is that the driving speed is sacrificed because high-precision positional accuracy on the mask is required. The reason why the position accuracy of the normal light shielding mechanism on the mask is required is that the purpose of the light shielding mechanism is to use the sequence control for repeatedly exposing only a part of the pattern of the mask. This is because it is necessary to form a light-shielding portion only to cover the accuracy, and the efficiency of using the mask is reduced.

[0062]

As described above, according to the projection exposure method and the projection exposure apparatus according to the present invention, unnecessary energy is supplied to the projection optical system and / or the mask without lowering the throughput of the exposure processing. Without this, it is possible to prevent the imaging characteristics from deteriorating.

[Brief description of the drawings]

FIG. 1 is a schematic view of a projection exposure apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between a one-shot area and a wafer according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a relationship between a one-shot area and a wafer according to another embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a one-shot area and a light shield according to an embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a one-shot area and a light shield according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Illumination optical system 3 ... Normal light-shielding mechanism 4, 8 ... Specific shot light-shielding mechanism 5 ... Relay optical system 6 ... Reflector mirror 9 ... Reticle stage 10 ... Projection exposure apparatus 201,301 ... 1st area 202,302 ... One-shot exposure areas 203 to 209, 303 to 309 ... Unnecessary areas 401, 501 ... Light-shielding blades 402, 502 ... Illumination areas R ... Reticles PL ... Projection optical system W ... Wafers

Claims (10)

[Claims] 1. A method for forming a plurality of first regions having the same pattern on the surface of a photosensitive substrate, wherein at least two adjacent first regions are defined as one shot region.
Illuminating a mask on which two or more mask patterns corresponding to the region are formed, and forming images of the two or more mask patterns formed on the mask on the surface of the photosensitive substrate via a projection optical system. Is a projection exposure method for exposing a plurality of shots to the surface of the photosensitive substrate, wherein, among the plurality of shots, all of two or more mask patterns on the mask are transferred onto the photosensitive substrate. Projection exposure, wherein, during exposure of a specific shot that does not need to be performed, an image of a mask pattern that does not need to be transferred onto the photosensitive substrate among mask patterns on the mask is limited. Method. 2. A single first region is defined as one shot region,
A first mask on which a first mask pattern corresponding to the first region is formed is illuminated, and an image of the first mask pattern formed on the first mask is formed on a surface of a photosensitive substrate via a projection optical system. By repeatedly forming an image, a first projection exposure for exposing a plurality of shots to the surface of the photosensitive substrate, and two or more first regions adjacent to each other as one shot region, A second mask on which two or more corresponding second mask patterns are formed is illuminated, and images of the two or more second mask patterns formed on the second mask are formed on the photosensitive substrate via a projection optical system. Repeating the imaging on the surface, and performing a second projection exposure of exposing a plurality of shots on the surface of the photosensitive substrate, for different layers of the same photosensitive substrate, Multiple projection exposures At the time of exposure, when exposing a specific shot in which it is not necessary to transfer all of the two or more second mask patterns on the mask onto the photosensitive substrate, two or more second mask patterns on the second mask are exposed. A projection exposure method, wherein an image of a second mask pattern that does not need to be transferred onto the photosensitive substrate is restricted from being formed. 3. When exposing the specific shot, an image of a mask pattern that does not need to be transferred onto the photosensitive substrate among two or more of the mask patterns is formed outside the photosensitive substrate. 2. The projection exposure method according to claim 1, wherein restriction is made. 4. When exposing the specific shot, an image of a second mask pattern that does not need to be transferred onto the photosensitive substrate among two or more of the second mask patterns is formed on the outside of the photosensitive substrate. 3. The projection exposure method according to claim 2, wherein the operation is restricted. 5. The method according to claim 1, wherein, when exposing the specific shot, the mask is used to limit formation of an image of a mask pattern that does not need to be transferred onto the photosensitive substrate among mask patterns on the mask. 4. The projection exposure method according to claim 1, wherein a part of the exposure illumination light for illuminating the light is shielded. 6. When the specific shot is exposed, an image of a second mask pattern which does not need to be transferred onto the photosensitive substrate among the second mask patterns on the second mask is restricted. 5. The projection exposure method according to claim 2, wherein part of the illumination light for exposure for illuminating the second mask is blocked. 7. A mask stage for holding a mask on which two or more mask patterns for forming two or more first regions of a predetermined pattern on the surface of a photosensitive substrate in one shot, and illuminating the mask An illumination optical system; a projection optical system that forms images of two or more mask patterns formed on the mask on a surface of the photosensitive substrate via a projection optical system; and two or more mask patterns on the mask. During exposure of a specific shot that does not need to be transferred onto the photosensitive substrate, an image of a mask pattern that does not need to be transferred onto the photosensitive substrate among the mask patterns on the mask is formed. A projection exposure apparatus having a specific shot restriction mechanism for restricting the operation. 8. The specific shot restricting mechanism is a specific shot light shielding mechanism that blocks a part of the exposure illumination light for illuminating the mask, and the specific shot light shielding mechanism is provided for each shot. 4. The projection exposure apparatus according to claim 3, wherein the projection exposure apparatus is provided separately from a normal light-shielding mechanism that does not change, and has a lower position accuracy than the normal light-shielding mechanism, but performs a faster light-shielding operation. 9. The projection exposure apparatus according to claim 8, wherein the specific shot light shielding mechanism is disposed near a plane optically conjugate with the mask. 10. The projection exposure apparatus according to claim 8, wherein the specific shot light shielding mechanism is supported by the mask stage.