JPH07142362A - Exposing method - Google Patents

Abstract

PURPOSE:To improve throughput when a pattern of a reticle formed by dividing a plurality of chip patterns in a scanning direction is exposed on each shot area on a wafer by a step and scan system. CONSTITUTION:A three-reticle pattern is exposed by a scan exposure system in a scanning direction on shot areas SA1-SA68 on a wafer W. Since a shot area SA1 of an outer periphery of the wafer W is a defective shot area where only one chip pattern is exposed, the wafer W is scanned only by 1/3 of a full field in a reverse direction to a locus T1 in synchronization with scanning of a slitlike emitting area by one chip pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, for example, positions each shot area on a wafer at a scanning start position and then synchronously scans a reticle and a wafer with respect to a slit-shaped illumination area. The present invention relates to an exposure method suitable for application when exposure is performed by a so-called step-and-scan exposure apparatus that sequentially exposes a pattern to each shot area.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor element, a liquid crystal display element, a thin film magnetic head, or the like is manufactured by using a photolithography technique, a pattern of a photomask or a reticle (hereinafter, collectively referred to as a "reticle") is projected and projected. A projection exposure apparatus that exposes a wafer (or a glass plate or the like) coated with a photoresist or the like via a system is used. Recently, the size of one chip pattern of a semiconductor element tends to be large, and a projection exposure apparatus is required to have a large area for exposing a pattern having a larger area on a reticle onto a photosensitive substrate.

In order to meet such an increase in area, after each shot area on the wafer is stepped to the scanning start position, for example, a rectangular, arcuate, or hexagonal illumination area (this is called a "slit-shaped illumination area"). By synchronously scanning the reticle and the wafer, a pattern having a larger area than the slit-shaped illumination area on the reticle is sequentially exposed to each shot area, so-called step-and-step.
A scanning type projection exposure apparatus has been developed. Hereinafter, the method of performing exposure while synchronizing the reticle and the wafer in synchronization, including the case of performing the exposure by the step-and-scan method, is referred to as the “scan exposure method”.

By the way, in the pattern area of the reticle,
A plurality of identical (or different) chip patterns may be drawn. In this case, in the normal batch exposure method, like the shot area in the peripheral portion of the wafer, there is only a shot area where there is room to project a part of the chip pattern images of the plurality of chip pattern images on the reticle. The image of the entire pattern of the reticle was also exposed when the exposure was performed on the (hereinafter, referred to as "chipped shot area").

Similarly, when exposing a reticle R formed by dividing a plurality of such chip patterns in the scanning direction by a scan exposure method to a defective shot area on the wafer, the reticle and the wafer are respectively exposed. The exposure was performed by scanning for the same length (full field length) as the case of exposing the image of the entire chip pattern on the reticle.

[0006]

In the prior art as described above, when a part of the chip pattern image on the reticle is exposed to the defective shot area on the wafer by the scan exposure method, the defective shot area is exposed. Unnecessary regions (eg, the edge of the wafer) in the vicinity of were also scanned with respect to the exposure region conjugate with the slit-shaped illumination region. Therefore,
There is an inconvenience that the unnecessary time for scanning the unnecessary area is generated, and the exposure time is long and the throughput of the exposure process is low.

In view of the above problems, the present invention uses a step-and-scan method to form a reticle pattern formed by dividing a plurality of circuit patterns (chip patterns) in the scanning direction into shot areas on a wafer. It is an object of the present invention to provide an exposure method capable of shortening the exposure time and improving the throughput of the exposure step when performing the exposure.

[0008]

A first exposure method according to the present invention is, for example, as shown in FIGS. 1 and 6, an illumination optical system (1-5, 8) for illuminating an illumination area (21) having a predetermined shape. )
Then, a mask stage (9) for scanning a mask (R) on which a transfer pattern is formed in a predetermined scanning direction with respect to the illumination area, and a photosensitive substrate (W) are placed, and this substrate is placed. A substrate stage (1 that two-dimensionally positions and scans this substrate in a direction corresponding to the predetermined scanning direction)
4) is used to align the mask (R) and the shot areas to be exposed in the plurality of shot areas on the substrate (W) by the stepping operation of the substrate stage to the acceleration start position of the scanning exposure, The pattern of the mask (R) is obtained by synchronously scanning the mask (R) and the substrate (W) in the scanning direction with respect to the illumination area (21) via the substrate stage (14) and the mask stage (9). Is sequentially exposed to each shot area on the substrate (W).

Further, according to the present invention, a plurality of circuit patterns are formed on the mask (R) by being divided in the scanning direction, and the mask (R) is formed in the shot area on the substrate (W). A shot area (SA1) in which only a part of the plurality of circuit patterns can be exposed
When the pattern of the mask (R) is exposed on the mask (R) and the shot area (S
A1) is aligned with the acceleration start position, and the mask (R) is partially removed in the scanning direction with respect to the illumination area (21) through the mask stage (9).
The substrate (W) is exposed through the substrate stage (14) onto the shot area (SA1), which is partially cut off, in synchronization with the movement of the length of the circuit pattern exposed to A1). After scanning for the length corresponding to the circuit pattern (trajectory T1), the mask (R) is set to the next acceleration start position via the mask stage (9), and the substrate ((R)) is moved via the substrate stage (14). W) is set at the acceleration start position of the shot area (SA2) to be exposed next.

In this case, the variable field diaphragms (6A, 6B, 6A, 6B, 6A, 6B, 6A, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6C, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6B, 6C, 6D, 6D, 6F, 6D, 6F, 6G
7) is provided, and the length of the circuit pattern in which the mask (R) is exposed through the mask stage (9) in the scanning direction with respect to the illumination area (21) to the shot area (SA1) in which a part thereof is missing In synchronism with the movement by an amount, the substrate (W) is scanned through the substrate stage (14) by a length corresponding to the circuit pattern exposed on the shot area (SA1) in which a part thereof is cut off. At this time, by changing the shape of the illumination area (21) via the field stop, a part of the shot area (SA1) on the substrate (W) in the mask (R) is cut off at most. Illumination pattern (2) on the circuit pattern (PA2, PA3) where only the pattern of
It is designed so that 1) does not pass.

[0011]

According to the present invention, for example, as shown in FIG. 2, the pattern area of the mask (R) is, for example, 3 in the scanning direction.
Is divided into individual partial pattern areas (PA1 to PA3),
A chip pattern is drawn in each partial pattern area. On the other hand, for example, as shown in FIG. 6, in the shot area (SA1) on the outer peripheral portion of the substrate (W), only one of the three chip patterns on the mask (R) is completely completed. Can be exposed, and only two chip patterns can be exposed in the shot area (SA2) adjacent thereto. That is, the shot areas (SA1, SA2) are shot areas partially lacking.

Then, a shot area (SA
To expose 1), only the pattern of the partial pattern area (PA3) on the mask (R) has to be exposed. Therefore, in FIG. 2, the area corresponding to the illumination area (21) is synchronized with the scanning of only the partial pattern area (one of PA1 to PA3) with respect to the illumination area (21). As shown in FIG. 6, 1/3 of the shot area (SA1) on the substrate (W) is scanned corresponding to the locus (T1).

After that, the substrate stage (14) is steppingly driven to set the shot area (SA2) on the substrate (W) at the acceleration start position, and then the partial pattern area with respect to the illumination area (21) in FIG. In synchronization with scanning only (PA3, PA2 or PA2, PA1), 2/3 of the shot area (SA2) is scanned corresponding to the locus (T2). With such a sequence, the exposure time is shortened and the throughput is improved as compared with the conventional method of always scanning for the full field.

When performing exposure by the scan exposure method, a predetermined run-up section is required before the mask (R) and the substrate (W) are scanned at a predetermined speed. Therefore, in order to prevent the pattern of the mask (R) from being exposed on the substrate (W) in such an approach section, the light emission of the light source in the illumination optical system is stopped, and the illumination light from the light source is shuttered. It is necessary to perform operations such as blocking the light or changing the illumination area (21) to close the illumination area (21).
In order to make the illumination area (21) variable in this way, a variable field diaphragm (6A, 6B, 7) may be provided in the illumination optical system. Then, specifically, in order to expose only the patterns of the partial pattern areas (PA1, PA2) of the mask (R) of FIG. 2 on the substrate (W), as shown in FIGS. It suffices that the illumination area (21) is not applied to the partial pattern area (PA3) which is not the exposure target through the variable field stop.

When the illumination area (12) is made variable by using such a variable field stop, for example, in FIG. 6, from the shot area (SA6) where only the pattern of one partial pattern area can be exposed. When stepping into the shot area (SA7) where the patterns of the two partial pattern areas can be exposed, with the illumination area (21) closed, the amount shown by the dotted line trajectory (U6) on the shot area (SA6). The mask (R) side is scanned by an amount corresponding to. Then, in the next shot area (SA7), the illumination area (2
1) is opened and the substrate (W) is moved to the locus (T7) in synchronization with scanning the mask (R) in the direction opposite to the case of the shot area (SA6) by an amount corresponding to the locus (T7). Scan correspondingly. This eliminates unnecessary movement and shortens the exposure time.

In summary, in order to shorten the exposure time, it is desirable to set the exposure sequence according to the following criteria. In the shot area where a part of the substrate (W) is lacking, the area where the pattern of the partial pattern areas (PA1 to PA3) on the mask (R) can be exposed only at most is not exposed.

Each shot area (SA1) on the substrate (W)
To SA68), the patterns of the partial pattern areas (PA1 to PA3) on the mask (R) are exposed to the corresponding partial exposure areas. The scanning directions in shot areas that are continuously exposed are made opposite to each other. As a result, the mask (R) only needs to reciprocate. After the exposure to a certain shot area is completed, the substrate stage (1
The substrate (W) is stepped to the acceleration start position of the next shot area via 4). During the stepping movement of the substrate (W), the mask (R) side is also moved to the acceleration start position.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. This embodiment applies the present invention to an exposure method in a step-and-scan type projection exposure apparatus. FIG. 1 shows a projection exposure apparatus used in this embodiment. In FIG. 1, a reticle R has a rectangular slit shape by a light source 1 and an illumination optical system including an illumination light shaping optical system 2 to a relay lens 8. Is illuminated with a uniform illuminance, and the circuit pattern image of the reticle R in the slit-shaped illumination area 21 is transferred onto the wafer W via the projection optical system 13. Examples of the light source 1 include an excimer laser light source such as an ArF excimer laser or a KrF excimer laser, a metal vapor laser light source, a pulse light source such as a harmonic generator of a YAG laser, or a combination of a mercury lamp and an elliptical reflecting mirror. Continuous light sources can be used.

In the case of a pulsed light source, the exposure is turned on or off by controlling the power supplied from the power source device for the pulsed light source, and in the case of a continuous light source, the exposure is turned on or off in the illumination light shaping optical system 2. Can be switched by.
However, in this embodiment, since the movable blind (variable field diaphragm) 7 is provided as described later, the movable blind 7
The exposure may be switched on or off by opening or closing.

In FIG. 1, the illumination light from the light source 1 reaches the fly-eye lens 3 after the illumination light shaping optical system 2 sets the luminous flux diameter to a predetermined value. Fly eye lens 3
A large number of secondary light sources are formed on the exit surface of, and the illumination light from these secondary light sources is condensed by the condenser lens 4 and reaches the movable blind (variable field diaphragm) 7 via the fixed field diaphragm 5. Although the field stop 5 is arranged on the condenser lens 5 side of the movable blind 7 in FIG. 1, it may be arranged on the opposite side of the relay lens system 8 side.

A rectangular slit-shaped opening is formed in the field stop 5, and the light flux passing through this field stop 5 becomes a light flux having a rectangular slit-shaped cross section and is incident on the relay lens system 8. The relay lens system 8 is a lens system that makes the movable blind 7 and the pattern forming surface of the reticle R conjugate with each other, and the movable blind 7 has two blades (light shielding plate) that define the width in the scanning direction (X direction) described later. 7A, 7B and two blades (not shown) that define the width in the direction perpendicular to the scanning direction. The blades 7A and 7B that define the width in the scanning direction are supported by the driving units 6A and 6B so as to be independently movable in the scanning direction. In this embodiment, the illumination light is emitted only within the slit-shaped illumination area 21 on the reticle R set by the fixed field stop 5 and further within the desired exposure area set by the movable blind 7. The relay lens system 8 is an optical system that is telecentric on both sides, and the slit-shaped illumination area 21 on the reticle R maintains the telecentricity.

The reticle R of this example is placed on the reticle stage 9, and an image of the circuit pattern defined by the movable blind 7 in the slit-shaped illumination area 21 on the reticle R is projected onto the projection optical system. Wafer W through 13
It is projected onto and exposed. An area on the wafer W that is conjugate with the slit-shaped illumination area 21 is defined as a slit-shaped exposure area 22. Further, in the two-dimensional plane perpendicular to the optical axis of the projection optical system 13, the scanning direction of the reticle R with respect to the slit-shaped illumination area 21 is set as the + X direction (or the −X direction) and is parallel to the optical axis of the projection optical system 13. Let the direction be the Z direction.

In this case, the reticle stage 9 is driven by the reticle stage drive unit 10 to scan the reticle R in the scanning direction (+ X direction or −X direction), and the movable blind 7 is moved.
The operation of the driving units 6A and 6B is performed by the movable blind control unit 11
Controlled by. The main control system 12 that controls the operation of the entire apparatus controls the operations of the reticle stage drive unit 10 and the movable blind control unit 11. On the other hand, the wafer W is placed on the wafer stage 14, and the wafer stage 1
X is for positioning the wafer W in a plane perpendicular to the optical axis of the projection optical system 13 and for scanning the wafer W in the ± X directions.
Y stage and Z for positioning the wafer W in the Z direction
It is composed of stages and the like. The main control system 12 controls the positioning operation and the scanning operation of the wafer stage 14 via the wafer stage drive unit 15.

As shown in FIG. 2, when the pattern image on the reticle R is exposed to each shot area on the wafer W through the projection optical system 13 by the scan exposure method, the field stop 5 shown in FIG. Reticle R in the −X direction (or + X direction) with respect to the slit-shaped illumination area 21 set by
The scanning at a speed V _R. Further, assuming that the projection magnification of the projection optical system 13 is β, the + X direction (or −X direction) with respect to the slit-shaped exposure area 22 is synchronized with the scanning of the reticle R.
Then, the wafer W is scanned at the speed V _W (= β · V _R ). As a result, the circuit pattern images of the reticle R are sequentially transferred onto the shot area SA on the wafer W.

Further, in this embodiment, by driving the blades 7A and 7B of the movable blind 7 of FIG. 1, one edge portion 21 in the scanning direction of the illumination area 21 of FIG.
A and the other edge portion 21b can be moved in the scanning direction. However, since the fixed field stop 5 is provided in FIG. 1, even when the movable blind 7 is fully opened, the width of the illumination area 21 in the scanning direction is D, and the movable blind 7 changes the width of the illumination area 21. Used when narrower than D. Furthermore, during normal exposure, the width of the illumination area 21 is set to D, and the movable blind 7 is used at the start and end of the exposure.

In the present embodiment, as shown in FIG. 2, the pattern area surrounded by the light-shielding band ST of the reticle R is defined by boundary lines 23 to 26, and three pattern areas are formed in a direction parallel to the X axis which is the scanning direction. It is divided into partial pattern areas PA1 to PA3, and the same circuit pattern is drawn in each of these three partial pattern areas PA1 to PA3. That is, the reticle R is a so-called three-piece reticle in the scanning direction, and correspondingly, the shot area SA on the wafer W is also divided into three partial shot areas SAa to SAc in the direction parallel to the X-axis, and each partial shot. The same chip pattern is formed in the regions SAa to SAc by the exposure process up to that point. And
In principle, partial shot areas SAa, SAb and SAc
Partial pattern areas PA1 on the reticle R
The circuit pattern images of PA2 and PA3 are projected and exposed.
In this case, since the pattern of the reticle R is inverted and projected onto the wafer W by the projection optical system 13, the partial pattern areas PA1 to PA3 and the partial shot areas SAa to are exposed.
The array direction is opposite to that of SAc.

However, since the patterns of the partial pattern areas PA1 to PA3 are the same, in practice, for example, a sequence for exposing the partial shot area SAa on the wafer W with the pattern image of the partial pattern area PA2 or PA3 on the reticle R is used. May be adopted. Note that different circuit patterns may be drawn in the three partial pattern areas PA1 to PA3 on the reticle R. In this case, different chip patterns are formed in the partial shot areas SAa to SAc of the shot area SA on the wafer W, and the partial shot areas SAa to SAc and the partial pattern areas PA1 to PA3 are in a 1: 1 correspondence. There is.

The arrangement and number of such partial pattern areas of the reticle R are input to the memory 17 via the input unit 16 such as the keyboard of FIG. 1, and the main control system 12 determines the memory 17 before determining the exposure sequence. The pattern information regarding the reticle R is read from. Regarding the arrangement of shot areas on the wafer W (shot arrangement), the position of a predetermined mark among the alignment marks attached to each shot area on the wafer W is detected by a wafer alignment system (not shown). It can be calculated from the detection result (see, for example, JP-A-61-44429).

Next, an example of an operation when performing exposure by the step-and-scan method in this embodiment will be described. In this case, the conventional exposure method can be applied to the shot area completely on the exposure surface of the wafer W, such as the shot area SA in FIG. There is a shot area (a chipped shot area) in which only the circuit pattern image of one or two of the partial pattern areas PA1 to PA3 can be exposed. In such a defective shot area, only one or two circuit patterns of the partial pattern areas PA1 to PA3 on the reticle R are exposed as follows.

First, the operation on the reticle R side will be described with reference to FIGS.
This will be described with reference to FIG. In this embodiment, 2 on the wafer W
When performing continuous exposure to individual shot areas, use the reticle
R sets the exposure sequence to perform a reciprocating motion.
This eliminates unnecessary movement on the reticle R side. Figure
3 is the scanning speed V of the reticle R when reciprocating._RStrange
In FIG. 3, first, the period T₁With reticle
Acceleration of R begins and a predetermined settling period T_SEReticle after
R scan speed V_RPeriod T is stable₂Exposed to
Be done. After that, period T₃The reticle R is decelerated inside
The substrate T immediately after the reticle R is stopped _FourReticle R
Acceleration in the opposite direction begins.

Subsequent settling period T_SEAfter the reticle
R speed V_RPeriod T is stable _FiveIs exposed to
It After that, period T₆The reticle R is decelerated and
After that, this operation is repeated. Also, reticle R acceleration
Period T₁And T_FourIn the latter half of the process, acceleration is performed on the wafer W side as well.
The reticle R deceleration period T₃And T₆From the latter half of
Each acceleration period T₁And T_FourThe first half of the
Next step of the wafer W is performed by the stepping movement of the wafer 14.
Area is at the scanning exposure acceleration start position (scan start position)
Is set.

Next, for example, when the reticle R is scanned in the -X direction to expose only the circuit patterns of the two partial pattern areas PA1 and PA2 on the reticle R, the movable blind 7 of FIG. An example of the operation will be described with reference to FIGS. 4 and 5. FIG. 4 shows the change of the slit-shaped illumination area 21, and FIG. 5 shows the illumination area 2 corresponding to FIG.
The movement position of the two edge parts 21a and 21b of 1 is shown. 5, the horizontal axis represents the elapsed time t, the vertical axis represents the X-coordinate X _B of the X-coordinate X _A and the edge portion 21b of the edge portion 21a, the movement position of the linear 28A and 28B are edge portions 21a, straight 27A And 27B show the moving position of the edge portion 21b. These two edge portions 21a and 21b
Are blades 7A and 7A of the movable blind 7 of FIG. 1, respectively.
It is a projection image of the inner edge part of the edge part of B or the fixed field stop 5. In FIG. 5, the sign of the X coordinate is negative, and X _A0 <X _B0 holds.

In this case, by driving the blades 7A and 7B of the movable blind 7 shown in FIG.
The moving positions of the two edge portions move along the straight lines 27A, 28B and 28A, 28B in FIG.
It changes like (a)-(c). That is, first, at the scanning start time t _s in FIG. 5, both the edge portions 21a and 21b are at the position X _B0 , and the illumination area 21 is completely closed.
After that, the position of the edge portion 21a changes according to the straight line 28A, and at the time point t ₁ , as shown in FIG.
The edge portion 21a of No. 1 moves together with the light-shielding band ST of the reticle R (correctly, the boundary line 23 of the light-shielding band ST), and the edge portion 2
1b remains stationary and the width of the illuminated area 21 extends to d ₁ .

After that, when the width of the illumination area 21 becomes D
Edge portion 21a is at position X_A0Stop at, for example, time t
₂Then, the edge portions 21a and 21b are respectively located at the position X._A0Over
And X _B0Remains stationary, as shown in FIG.
The second partial pattern area PA2 of the reticle R is the illumination area.
It depends on 21. Then, the reticle R is further scanned.
The boundary line 25 between the partial pattern areas PA2 and PA3.
Immediately after passing over the edge portion 21b, the straight line 27B in FIG.
As shown, the edge portion 21b follows the boundary line 25 and is -X.
Direction, at time t₃Then, as shown in Fig. 4 (c),
The width of the bright area 21 is d₃Is narrowed to. And the partial
Time t when exposure of the turn area PA2 is completed_fAt
The two edges 21a and 21b are completely closed.

By this operation, an unnecessary pattern other than the circuit patterns of the two partial pattern areas PA1 and PA2 on the reticle R is not exposed on the wafer W. Similarly, when the wafer W is exposed with only the circuit patterns of the partial pattern area PA1, the partial pattern area PA3 on the reticle R, or the two partial pattern areas PA3 and PA2, the movable blind 7 is operated to illuminate the illumination area. By opening and closing 21 in the scanning direction, an unnecessary pattern is not exposed on the wafer W. Thereby, for example, the run-up period until the scanning speed of the wafer W reaches a constant speed during exposure,
Alternatively, an unnecessary pattern is not exposed on the wafer W during the stepping drive of the wafer W to the scanning start position of the next shot area.

Next, with reference to FIG. 6, an example of an exposure sequence for exposing each shot area on the wafer W with the pattern of the three-piece reticle R in the scanning direction shown in FIG. 2 will be described. FIG. 6 shows a wafer W to be exposed in the present embodiment. In FIG. 6, 68 shot areas SA1 to SA68 are arranged on the wafer W in the X direction (scanning direction) and the Y direction.
Are arranged at a predetermined pitch in the direction. In these shot areas, the shot areas SA1, SA6, SA63, and SA68 arranged on the outer peripheral portion of the wafer W are one partial pattern area PA3 of the three partial pattern areas PA1 to PA3 of the reticle R, or A shot area SA2 to SA5, SA7, SA14, SA54, S is a shot area where only the pattern image of PA1 can be exposed.
A55, SA62, and SA64 to SA67 are two partial pattern areas PA3 and PA on the reticle R, respectively.
2 or a pattern image of PA1 and PA2 is a shot area that can be entirely exposed. Only the pattern images of the partial pattern areas (PA1, PA2 or PA3) on the reticle R that can be completely exposed are exposed to these shot areas.

When the exposure is performed by the scan exposure method, the exposure is started from the first shot area SA1 on the upper left of the wafer W, and the shot area SA of the first row arranged in the -Y direction.
1 to SA6 are sequentially exposed. Then, the shot areas SA7 to SA14 of the second row arranged in the + Y direction are sequentially exposed, and thereafter, the shot areas of one row are similarly exposed, and finally, the shot area SA68 at the lower left is exposed. The exposure of the wafer W is completed. 6, the loci T1, T2, T3, ... Shown by solid lines indicate the loci of the slit-shaped exposure areas 22 of FIG. 2 with respect to the wafer W when the shot areas SA1, SA2, SA3 ,. The wafer W is actually moving in the direction opposite to the trajectories T1, T2, .... However, in addition to the trajectories T1, T2, ..., Actually, an approach section for keeping the scanning speed constant is necessary. Further, the reticle R is scanned in a direction conjugate with the loci T1, T2, ... And the projection optical system 13.

First, the first shot area S on the wafer W is
In order to perform exposure on A1, in synchronization with scanning the partial pattern area PA3 of the reticle R with respect to the illumination area 21 in FIG. 2, one shot area SA1 for the slit-shaped exposure area in FIG. The third partial shot area, which is an area of / 3, is scanned in the direction opposite to the trajectory T1. After that, during the deceleration period of the reticle R, the lower edge portion of the second shot area SA2 is set to the scanning start position by the stepping drive of the wafer stage 14, and then the reticle R is moved to the illumination area 21 in FIG. In synchronization with the scanning of the partial pattern areas PA3 and PA2, in FIG. 6, the shot area SA1 is set for the slit-shaped exposure area.
The third and second partial shot areas that are ⅔ of the area are scanned in the direction opposite to the trajectory T2. Then, similarly, the shot areas SA3 to SA5 are alternately scanned in the opposite direction by 2/3 of the full field to expose the pattern images of the two partial pattern areas on the reticle R, respectively.

Next, the last shot area SA on the first row
In 6, the shot area S is used for the slit-shaped exposure area.
The area of 1/3 of A6 is scanned in the direction opposite to the trajectory T6.
At this time, on the reticle R side, the third partial pattern region is scanned in a direction conjugate with the trajectory T6. However, in the shot area SA7 to be exposed next, since the pattern images of the partial pattern areas of the reticle R can be exposed in each of the two partial shot areas, even after the exposure to the shot area SA6 is completed,
With the illumination area 21 in FIG. 2 closed, the reticle R is scanned in a direction conjugate with the locus U6. As a result, a boundary line 24 between the partial pattern areas PA1 and PA2 is set near the outside of the edge portion 21a of the illumination area 21.

Then, in FIG. 6, while the reticle R is moving in the direction corresponding to the locus U6, the wafer stage 14 is driven by stepping, and the lower side of the first shot area SA7 of the second row of the wafer W is driven. The edge part of is set to the acceleration start position. Then, in synchronization with the scanning of the partial pattern areas PA2 and PA3 of the reticle R in the −X direction with respect to the illumination area 21 in FIG. 2, 2 of the shot area SA7 with respect to the slit-shaped exposure area in FIG. / 3
The area is scanned in the direction opposite to the trajectory T7. Then, the following shot areas SA8 to SA13 are alternately scanned by the full field in the opposite direction to expose the pattern images of all the partial pattern areas on the reticle R, respectively. Regarding the last shot area SA14 in the second row, after exposure to two partial shot areas is performed, the reticle R is further moved by an amount corresponding to one partial shot area, and The lower edge portion of the first shot area SA15 in the third row is set as the acceleration start position.
Hereinafter, full field exposure is performed up to the final shot area SA54 in the sixth row.

After that, the first shot area S of the seventh row
At A55, the wafer W is scanned in the direction opposite to the trajectory T55 in synchronization with the scanning of the reticle R in the direction conjugate with the trajectory T55, and then the illumination area 21 is closed to move the reticle R further in the direction conjugate with the trajectory U55. The wafer W is scanned, and the next shot area SA56 is moved to the acceleration start position. Further, from the next shot area SA56 on the seventh row to the last shot area SA68 on the eighth row, an exposure sequence from the first shot area SA1 on the first row to the shot area SA13 on the second row is set. The exposure is performed in a symmetrical sequence.

As described above, according to the present embodiment, in FIG.
~ SA7, SA14, etc.), the unnecessary pattern is not exposed, so the exposure time is shortened and the throughput of the exposure process is improved. Further, in the above-described embodiment, FIG.
As shown in FIG. 3, the partial shot areas SAa, SAb and SAc of the respective shot areas SA correspond to the partial pattern areas PA1, PA2 and PA3 on the reticle R at a ratio of 1: 1. The pattern image of the area PA1 is exposed. Furthermore,
As shown in FIG. 6, in the shot arrangement on the wafer W, one row of shot areas (for example, shot areas SA1 to SA) arranged in the non-scanning direction (Y direction) perpendicular to the scanning direction.
In 6), the scanning directions between the adjacent shot areas are opposite to each other. Such a sequence is rational in concept and easy to control.

Next, another exposure sequence for the wafer W of FIG. 6 will be described. First, since the same pattern is drawn in the partial pattern areas PA1 to PA3 of the reticle R shown in FIG. 2, for example, the third partial pattern on the reticle R is not necessarily present in the locus T1 of the shot area SA1 in FIG. It is not necessary to expose the pattern image of the area PA3. Therefore, for example, the shot areas SA1 and SA6 are exposed with the pattern image of the second partial pattern area PA2 on the reticle R, and the shot areas SA2 to SA5 and SA7 are exposed.
Alternatively, the pattern images of the two partial pattern areas PA1 and PA2 on the reticle R may be exposed. However, in this case, when the wafer W is stepped from the shot area SA7 to the shot area SA8, it is necessary to move the boundary line 26 of the reticle R to the vicinity of the outside of the illumination area 21.

Next, consideration will be given to the possibility of a sequence in which the scanning directions are made the same between shot areas adjacent to each other in the non-scanning direction. In this case, the shot area SA1 in FIG.
To the shot area SA2 after the pattern image of the third partial pattern area PA3 of the reticle R is exposed and the wafer W is stepping driven. A sequence of exposing the pattern image of is considered. This makes it possible to scan the shot areas SA1 and SA2 in the same direction, but scanning on the reticle R side always requires an approach section for performing acceleration / deceleration, and the reticle R is scanned between the shot areas SA1 and SA2. It is necessary to reposition in the direction.
Therefore, such a sequence proves to be disadvantageous.

The above embodiment is effective when the pattern area of the reticle R is divided into a plurality of parts in the scanning direction as shown in FIG. However, when the pattern area of the reticle R is divided into two partial pattern areas PA4 and PA5 in the Y direction which is the non-scanning direction as shown in FIG. Also, it is necessary to perform exposure by scanning a full field in the scanning direction.

In the embodiment of FIG. 1, the movable blind 7
Besides, since the fixed field stop 5 is provided, the width D of the slit-shaped illumination area 21 in the scanning direction at the time of normal exposure.
Can be set accurately. However, for example, Japanese Patent Laid-Open No. 4-
As disclosed in Japanese Patent No. 196513, the positioning accuracy of the movable blind 7 may be improved and the fixed field stop 5 may be omitted. Further, in the above embodiment, the shape of the slit-shaped illumination region 21, that is, the shape of the opening of the field stop 5 has been described as an example of a rectangle, but the shape is not limited to a rectangle. Further, it goes without saying that the projection optical system 13 may be a refraction system, a reflection system or a catadioptric system. Further, the present invention is not limited to the projection exposure apparatus,
It goes without saying that it can also be applied to a contact type or proximity type exposure apparatus. As described above, the present invention is not limited to the above-described embodiments, and various configurations can be taken without departing from the gist of the present invention.

[0047]

According to the exposure method of the present invention, a mask pattern formed by dividing a plurality of circuit patterns (chip patterns) in the scanning direction is step-and-stepped.
When each shot area on the substrate is exposed by the scan method, the shot area that is partially lacking is scanned by the length of the circuit pattern that can be exposed, so the exposure time is shortened. There is an advantage that the throughput of the exposure process can be improved.

Further, when the shape of the illumination area can be changed by using the variable field stop, the illumination area is closed on the circuit pattern on the mask which is unnecessary for the shot area where a part thereof is missing. Thus, there is an advantage that unnecessary exposure of the circuit pattern can be prevented. Although the exposure light may be blocked by a shutter or the like to stop the exposure, when the shape itself of the illumination area is changed, a circuit pattern to be exposed and an unnecessary circuit pattern are separated. There is an advantage that only the circuit pattern to be exposed can be exposed accurately.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an entire step-and-scan projection exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view provided for explaining an operation when performing exposure by a scan exposure method.

FIG. 3 is a diagram showing how the scanning speed V _R of the reticle changes during exposure by the scan exposure method.

FIG. 4 is a diagram showing an example of an opening / closing operation of a slit-shaped illumination area (12) when only a pattern of a predetermined partial pattern area on a reticle is exposed by a scan exposure method.

5 is a diagram showing the movement of two edge portions in the scanning direction of the slit-shaped illumination area corresponding to FIG. 4;

FIG. 6 is an enlarged plan view showing an example of a shot arrangement and an exposure sequence of a wafer to be exposed in the embodiment.

FIG. 7 is a plan view showing a reticle in which a pattern area is divided into two in the non-scanning direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 light source 3 fly-eye lens 5 fixed field diaphragm 7 movable blinds 7A, 7B blades 8 relay lens R reticle W wafer 9 reticle stage 10 reticle stage drive unit 11 movable blind control unit 12 main control system 13 projection optical system 14 wafer stage 15 Wafer stage drive unit 21 Slit-shaped illumination area 22 Slit-shaped exposure area PA1 to PA3 partial pattern areas SA, SA1 to SA68 shot areas SAa, SAb, SAc partial shot areas

Claims (2)

[Claims] 1. An illumination optical system for illuminating an illumination area having a predetermined shape, a mask stage for scanning a mask having a transfer pattern formed in a predetermined scanning direction on the illumination area, and a photosensitive substrate. A substrate stage that holds and positions the substrate two-dimensionally and scans the substrate in a direction corresponding to the predetermined scanning direction is used, and the mask and the plurality of substrates on the substrate are stepped by the stepping operation of the substrate stage. After aligning the shot area to be exposed in the shot area to the acceleration start position of scanning exposure, the mask and the substrate are moved in the scanning direction with respect to the illumination area via the substrate stage and the mask stage. In the exposure method, in which the mask pattern is sequentially transferred and exposed to each shot area on the substrate by scanning in synchronization, When a plurality of circuit patterns are formed on the substrate in a divided manner in the scanning direction and only a part of the plurality of circuit patterns of the mask can be exposed in the shot area on the substrate When exposing the pattern of the mask to the shot area lacking in, the mask and the shot area partially lacking on the substrate are aligned at the acceleration start position, and the illumination area is passed through the mask stage. On the other hand, in synchronization with the movement of the mask in the scanning direction by the length of the circuit pattern exposed in the shot area where the part is cut off, the part of the substrate is cut off via the substrate stage. After scanning for a length corresponding to the circuit pattern exposed on the shot area, while setting the mask at the next acceleration start position via the mask stage, An exposure method, characterized in that the substrate is set at an acceleration start position of a shot area to be exposed next through the substrate stage. 2. A variable field stop for changing the shape of the illumination area is provided in the illumination optical system, and the mask is partially cut off in the scanning direction with respect to the illumination area via the mask stage. A length corresponding to the circuit pattern exposed on the shot area where the substrate is partially cut off through the substrate stage in synchronization with the movement of the length of the circuit pattern exposed on the shot area. By changing the shape of the illumination area through the field stop when scanning only a minute, only a part of the shot area on the substrate in the mask is exposed at most. 2. The exposure method according to claim 1, wherein the illumination area does not pass over the circuit pattern.