JP2003224065A - Aligner and aligning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten aligning time in a lithography process. <P>SOLUTION: By scanning an original plate where a pattern is formed and irradiating the original plate with charged particle beams or electromagnetic waves, the pattern is transferred to a sample. At the time, acceleration in a scanning direction of the original plate is started and irradiation with the charged particle beam, or the electromagnetic wave is started during the acceleration of the original plate. Or, after starting the irradiation of the original plate with the charged particle beam or the electromagnetic wave, deceleration in the scanning direction of the original plate is started while irradiating it with the charged particle beam or the electromagnetic wave. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and an exposure method. More specifically, the present invention relates to an exposure apparatus and an exposure method used for transferring a pattern in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art In a lithography process for a semiconductor device, an exposure device is used to transfer a pattern formed on a mask onto a wafer. Conventionally, up to a semiconductor device having a design rule of 0.35 μm, of these exposure apparatuses, a device called a stepper (step and repeat aligner) has been used to perform pattern transfer. A stepper fixes a mask, irradiates exposure light, and transfers a pattern for every angle of view. Here, the angle of view is a range that can be resolved with high accuracy at one time.

By the way, the resolution R of the stepper is R =
It can be expressed as k · λ / NA. Here, k is an empirical constant, λ is the wavelength of the light source, and NA is the aperture coefficient of the lens. Therefore, in order to accurately transfer a finer pattern onto the wafer, it is necessary to shorten the wavelength of the exposure light and increase the aperture coefficient of the lens of the imaging optical system.

On the other hand, the aperture of the lens can be expressed as tan (sin ^-1 NA) using the aperture coefficient NA of the lens. Therefore, when the numerical aperture NA of the lens is increased, the numerical aperture of the lens is increased, and when the numerical aperture NA approaches 1, the required numerical aperture of the lens is rapidly increased. However, it is difficult to manufacture a large-diameter lens with low aberration over the entire surface.

Therefore, with the recent miniaturization of patterns,
From the 0.25 μm design rule, a device called a scanner (step and scan aligner) is often used as an exposure device. The scanner uses a long and narrow area with the maximum angle of view in the longitudinal direction as the exposure area, and scans in the opposite direction while synchronizing the mask and wafer in the direction perpendicular to this longitudinal direction, and scans the entire surface of the pattern on the mask. Is to be exposed. As a result, compared to the stepper, it is possible to suppress the enlargement of the lens diameter and maintain the accuracy of the lens. Therefore, it is possible to transfer a finer pattern with high accuracy.

In addition, 70 nm is required for further miniaturization.
According to the design rule, as an apparatus that can obtain higher resolution performance, application of an electron beam type scan type exposure apparatus that uses an electron beam instead of an optical method that uses light as an exposure light source is being considered. This exposure apparatus uses EPL (Elec
tron beam Projection Lithography) Exposure equipment. Also in the EPL exposure apparatus, in a state where the mask and the wafer are synchronized, scanning is performed in the opposite direction, and the irradiation position of the electron beam on the mask is relatively moved,
The entire surface of the pattern formed on the mask can be exposed to transfer the pattern to the wafer.

FIG. 6 is a schematic view showing the relative position where the central axis of the electron optical system moves on the mask 22 in the EPL exposure apparatus. As shown in FIG. 6, the pattern formed on the mask 22 is divided into four elongated stripes 24, 26, 28 and 30.

First, the mask 22 is set so that the central axis of the electron optical system is located at the scanning start position 72a below the stripe 24. In this state, the scanning of the mask is started with acceleration + A, and the central axis of the electron optical system is the arrow 72.
Move in the direction of.

When the central axis reaches the irradiation start position 72b,
End acceleration. Irradiation of the electron beam is started while the mask is continuously scanned at a constant speed. The central axis moves on the stripes 24 on the mask 22 at a constant speed in the direction of the arrow while being irradiated with an electron beam, and the pattern on the stripes 24 is transferred to the wafer.

When the central axis reaches the irradiation end position 72c,
Irradiation of the electron beam ends. At the same time, the acceleration-
At A, the scanning speed of the mask starts decelerating. The mask is
When the central axis reaches the scanning end position 72d, the velocity is 0
Next stop.

Thereafter, scanning of the mask stage 22 is started in the direction perpendicular to the arrow 72, and the central axis is moved in the direction of the arrow 80 on the mask 22. As a result, the central axis moves so as to come to the scan start position 74a of the adjacent stripe 26. The pattern of the stripe 74 is transferred in the same manner as the transfer of the stripe 24.

Similarly, by scanning the mask, the central axis is moved in the directions of the arrows 82, 76, 84, 78, and all the stripes 24, 26, 2 formed on the mask are moved.
The pattern is transferred to the wafer by irradiating with 8 and 30. After that, the mask 22 is returned again so that the central axis thereof comes to the scanning start position 72a of the stripe 24, and the transfer of the pattern is completed.

[0013]

By the way, when a pattern is transferred by the EPL exposure apparatus as described above, the electron beam is applied to the mask 22 when the acceleration is 0, that is, at a constant velocity. Only when scanning the mask with.

FIG. 7 shows a conventional EPL exposure apparatus,
7 is a graph showing the relationship between the acceleration of the scanning speed of the mask 22 and the elapsed time. In FIG. 7, the vertical axis represents acceleration and the horizontal axis represents time. As shown in FIG.
The mask 22 has an acceleration of ++ between a and b in which the central axis moves from the scanning start position to the irradiation start position.
Accelerated at A. Further, the mask is scanned at a constant speed with the acceleration set to 0 in the period from b to c when the central axis moves from the irradiation start position to the irradiation end position. Also, from the irradiation end position to the acceleration end position, the central axis is from cd to d.
In the meantime, the speed is decelerated by the acceleration -A, the deceleration is ended in d, the speed becomes 0, and the scanning ends.

Here, in order to transfer the pattern formed on the mask, the stripe is irradiated with the electron beam between b and c from the irradiation start position to the irradiation end position of the central axis, that is, , Only during the time T2 when the acceleration is 0, as shown in FIG. At this time, the mask is scanned at a constant speed, but this speed is determined by the surface density of the exposure energy with respect to the wafer and the sensitivity of the resist.

As described above, in the exposure time at the time of pattern transfer using the EPL exposure device, in order to actually transfer the pattern, in addition to the time T2 for irradiating the stripe with the electron beam, the scanning speed is constant. It requires an acceleration time between a and b, a deceleration time between c and d until the scanning is stopped, and a time for moving from one stripe to the scanning start position of an adjacent stripe. turn into. Therefore, it takes a lot of time for the exposure process, which is a problem in terms of throughput.

FIG. 8 is a graph showing the relationship between the exposure time per wafer and the acceleration. In FIG. 8, the vertical axis represents the exposure time (second) and the vertical axis represents the acceleration (G).
Indicates. As shown in FIG. 8, each exposure time includes an acceleration / deceleration time 90 in the longitudinal direction of the stripes, a movement time 92 between the stripes, an electron beam irradiation time and a deflection waiting time 94, an overhead time 9 such as wafer transfer and alignment.
Divided into 6.

As shown in FIG. 8, when the acceleration becomes small, the exposure time suddenly becomes long. Further, as the acceleration becomes smaller, the ratio of the acceleration / deceleration time 90 to the entire exposure time becomes larger.

As described above, the scanning speed while scanning the mask at a constant speed is determined by the surface density of the exposure energy with respect to the wafer and the sensitivity of the resist. Therefore, the time required to irradiate the electron beam during the uniform velocity scanning is 94
Is almost constant regardless of acceleration. Therefore, by shortening the acceleration / deceleration time when the electron beam irradiation is not performed,
It is also possible to shorten the exposure time. That is, in this case, the acceleration may be increased.

FIG. 9 shows the acceleration of the mask stage and the
It is a graph showing the relationship with the output. In FIG.
The vertical axis is the number of processed sheets per hour (sheets / hour),
The horizontal axis is acceleration (G). Note that here, the exposure conditions
As for the angle of view, the width is 20 mm and the length is 25 mm.
Then, the wafer size is set to 300 nmφ and the angle of view is set to 1
The number of wafers is 106 per wafer. Also, of the current
Density 0.16 A / cm ^TwoAnd the sensitivity of the resist is 5μ
C / cm^TwoI am trying.

As shown in FIG. 9, if the acceleration is increased, the throughput per unit time is increased, and the exposure time can be shortened.

However, in the EPL exposure apparatus, the electron beam transmitted through the mask is reduced to 1/4 and imaged. Figure 9
Therefore, in order to obtain a throughput of 35 sheets / hour, the mask needs an acceleration of 5 G or more. However, it is difficult to realize such high acceleration in a vacuum. Further, if the mask is accelerated with an excessively large acceleration, the device vibrates or the mask is deformed due to the reaction force associated with the acceleration, which makes it difficult to accurately transfer the pattern.

Therefore, the present invention provides an improved exposure apparatus and exposure method for the purpose of solving the above problems and shortening the exposure time and improving the throughput while suppressing the increase in acceleration. It is a proposal.

[0024]

An exposure method according to the present invention is an exposure method in which a pattern-formed original plate is scanned and the charged plate is irradiated with a charged particle beam or an electromagnetic wave to transfer the pattern to a sample. The acceleration of the original plate in the scanning direction is started, and the irradiation of the charged particle beam or the electromagnetic wave is started during the acceleration of the original plate.

In the exposure method of the present invention, after the original plate is started to be irradiated with the charged particle beam or the electromagnetic wave,
The deceleration of the original plate in the scanning direction is started.

The exposure method according to the present invention is an exposure method of scanning a pattern-formed original plate and irradiating the original plate with a charged particle beam or an electromagnetic wave to transfer the pattern to a sample. During the irradiation of the charged particle beam or the electromagnetic wave, deceleration in the scanning direction of the original plate is started.

The exposure method according to the present invention is characterized in that an electron beam is used as the charged particle beam.

Next, the exposure apparatus according to the present invention comprises a radiation source capable of emitting a charged particle beam or an electromagnetic wave, an original plate on which a pattern-formed original plate can be placed and scanned. A sample mounting table on which a sample can be mounted, and the radiation source irradiates the original plate with a charged particle beam or an electromagnetic wave while the original mounting table is accelerating and / or decelerating a scanning speed. Is something that can be done.

Further, the exposure apparatus according to the present invention comprises an optical system for forming an image of the charged particle beam or the electromagnetic wave on the sample.

Further, in the exposure apparatus according to the present invention, the optical system is a projection optical system.

Further, in the exposure apparatus according to the present invention, the charged particle beam is an electron beam.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will be omitted or simplified.

Embodiment. FIG. 1 is a schematic diagram showing an EPL exposure apparatus 100 according to an embodiment of the present invention. EPL (Electron beam Projection Lithography)
The exposure apparatus 100 is provided with the electron gun 2. The electron beam 4 is emitted from the electron gun 2. The electron beam 4 emitted from the electron gun 2 passes through the anode 6 and the molding diaphragm 8,
It is incident on the illumination optical system 10. The illumination optical system 10 includes an illumination deflector 12. The electron beam 4 enters the illumination optical system 10, passes through the illumination deflector 12, and reaches the mask stage 14. The mask 22 is attached to the mask stage 14.
Is placed. The electron beam 4 irradiates the mask 22, and the electron beam 4 that has passed through the mask 22 enters the imaging optical system 16. The image forming optical system 16 is provided with an objective deflector 18. Electron beam 4 incident on the imaging optical system 16
Passes through the objective deflector 18 and reaches the wafer stage 20. A wafer 34 is placed on the wafer stage 20. The wafer 34 is irradiated with the electron beam 4.
The central axis of the electron optical system in the EPL exposure apparatus 100 is an axis in the direction perpendicular to the electron gun 2.

Further, the mask stage 14 is provided with a mask stage operating means 70, and the wafer stage 20.
Is provided with a wafer stage operating means 72. Further, the mask stage operating means 70 and the wafer stage operating means 72 are connected to the position control means 74.

FIG. 2 is a schematic top view showing the mask 22 used in the EPL exposure apparatus 100. As shown in FIG. 2, the mask 22 is a thin plate-shaped substrate. Mask 2
2 has a pattern formed by being divided into four stripes 24, 26, 28 and 30. Further, in each of the stripes 24 to 30, 20 small areas each called a sub-field and having a size of about 1 mm are arranged in the horizontal direction and 100 in the vertical direction at a pitch of about 1.3 mm. Therefore,
The width of each stripe 24-30 is 26 mm. The subfield is formed of a silicon membrane.

Further, stripe 26 and stripe 28
A major strut region 32 is formed between and. The width of the major strut 32 is 10 mm.
The major strut is made of bulk silicon. The major struts 32 are provided to maintain the strength of the mask 22 because the subfields are formed of a silicon membrane.

Further, in FIG. 2, arrows 42, 50, 4
Reference numerals 4, 52, 46, 54, 48 and 56 indicate directions in which the central axis of the EPL electron optical system relatively moves on the mask 22 as a result of scanning by the mask stage 14.

EPL exposure apparatus 1 configured as described above
The function of 00 will be described. The electron gun 2 emits an electron beam 4. The anode 6 extracts the electron beam 4 and
The electron beam 4 is accelerated to 100 kV. Further, the forming diaphragm 8 forms the accelerated electron beam 4 into a square.

The illumination optical system 10 makes the molded electron beam 4 have a size of about 1 mm square. In addition, the illumination deflector 1
2 scans the electron beam 4 in the direction of arrow 38, that is, in each stripe in a direction perpendicular to the longitudinal direction so as to irradiate from one point on the long side of each stripe to one point on the opposite long side. To do. The electron beam 4 passes through the illumination optical system 10, is shaped and deflected, and then is irradiated onto the mask. The electron beam 4 irradiates the subfields formed on the stripes 24 to 30 and transfers the subfields, thereby transferring the stripes 24 to 30 on the wafer 34.

The mask 22 can be placed on the mask stage 14. Also, the mask stage operating means 70
Is the mask stage 14 with the mask 22 placed thereon.
Can be scanned in the direction indicated by arrow 40. By this scanning and scanning of the electron beam 4 by the illumination deflector 12, it is possible to irradiate the electron beam 4 on the entire surface of the pattern formed on the mask 22.

The image forming optical system 16 receives the electron beam 4 transmitted through the mask 22 and reduces it to 1/4. Also,
The objective deflector 18 moves in the direction of arrow 62, that is, in the direction perpendicular to the longitudinal direction of each stripe image transferred onto the wafer.
The electron beam 4 is scanned so that irradiation can be performed from one point on the long side of each stripe image to one point on the opposite long side. The electron beam 4 is reduced and deflected through the imaging optical system 16, and irradiates the wafer 34.

Further, here, the wafer stage operating means 72 replaces the wafer stage 20 with the mask stage 14.
The scanning can be performed in the opposite direction in synchronization with. That is, when the mask stage 14 scans in the direction of arrow 40, the wafer stage operating means 72 scans the wafer stage 20 in the direction of arrow 60.

Here, the pattern image is reduced to 1/4 on the wafer 34. The subfields on the mask 22 have a pitch of 1.3 mm. Therefore, the scanning speed or acceleration of the mask stage 14 is 4 × with respect to the scanning speed or acceleration of the wafer stage 20.
1.3 = 5.2 times.

Here, the positions of the mask stage 14 and the wafer stage 20 are measured by a laser interferometer (not shown) and transmitted to the position control means 74. The position control means 74 calculates an error from the target position and
By feeding back to the mask stage operating means 70 and the wafer stage operating means 72, the scanning speed of each stage is controlled. In exposure during acceleration / deceleration, the response speed of this feedback control is improved. Further, during exposure during acceleration / deceleration, the position control unit 74 calculates the predicted position of each stage 14, 20 in addition to feedback control, and transmits this to the mask stage operating unit 70 and the wafer stage operating unit 72. It also incorporates a feed-forward method of controlling by.

FIG. 3 is a flow chart for explaining the exposure method in the embodiment of the present invention. Less than,
A method of performing exposure using the EPL exposure apparatus 100 in this embodiment will be described with reference to FIG.

First, prior to the irradiation of the electron beam 4, the mask 22 is moved to the irradiation start position 42a (step S2). Here, as shown in FIG. 2, by scanning the mask stage 14, the mask 22 is moved so that the central axis of the electron optical system is located at the irradiation start position 42a of the stripe 24.

Next, the acceleration of the mask stage 14 is started at the acceleration + A, and the irradiation of the electron beam 4 on the mask 22 is started (step S4). Here, first, the electron beam 4 is emitted from the electron gun 2, accelerated by the anode 6, and then shaped through the shaping diaphragm 8. The electron beam 4 enters the irradiation optical system 10. The electron beam 4 incident on the illumination optical system 10 is about 1 m by the illumination optical system 10.
The illumination deflector 12 scans in the direction of an arrow 38 perpendicular to the arrow 42 and irradiates the mask 22 with the m-th angle. At the same time when the electron beam irradiation to the mask 22 is started, the mask stage operating means 70 is moved to the position control means 74.
In response to the signal from, the mask stage 14 starts scanning.

As a result, the central axis of the electron optical system is positioned on the stripe 22 as shown in FIG.
It moves from 2a in the direction of arrow 40 while gradually increasing the speed. Further, in synchronization with the scanning of the mask stage 14, the wafer stage operating means 72 accelerates the wafer stage 20 in the opposite direction to the mask stage 14 at an acceleration of 1 / 5.2 times + A. The electron beam 4 that has passed through the mask 22 is reduced to 1/4 through the imaging optical system 16 and is irradiated onto the wafer 34 while being scanned by the objective deflector in the direction of arrow 62.

Next, the acceleration of the mask stage 14 is completed (step S6). Here, the acceleration ends when the central axis of the electron optical system reaches the acceleration end position 42b on the stripe 24. At the same time, the acceleration of the wafer stage 20 also ends.

As a result, the mask stage 14 and the wafer stage 20 are scanned at a constant speed (step S).
8). Therefore, the central axis of the electron optical system is the stripe 24
Move upward in the direction of arrow 42 at a constant speed. Also during this period, the electron beam is irradiated as in the case of acceleration. Note that the speed at the time of this constant-speed scanning is the EPL exposure apparatus 100.
Is the maximum speed determined by the current density, the deflection waiting time by the illumination deflector 12 and the objective deflector 18, the sensitivity of the resist coated on the wafer, and the like.

Next, the deceleration of the mask stage 14 is started (step S10). Here, the EPL exposure device 10
When the central axis of 0 reaches the deceleration start position 42c, deceleration of the mask stage is started with acceleration -A. As a result, the central axis of the electron optical system moves in the direction of arrow 42 on the stripe 24 from 42c while gradually decreasing the speed. Also, at this time, in synchronization with the mask stage 14
In the opposite direction, the wafer stage is decelerated at an acceleration of −5.2 times −A. Also during this period, the electron beam 4 is irradiated as during acceleration.

Next, the deceleration of the mask stage 14 is finished, and at the same time, the irradiation of the electron beam 4 is finished (step S12). Here, when the irradiation end position 42d is reached, the scanning speed of the mask stage 14 becomes 0, and the mask stage is stopped. When this scanning is stopped, the deceleration of the mask stage 14 is finished, and the irradiation of the electron beam 4 is finished.

In this state, the transfer of the pattern of the stripe 24 is completed, and the pattern 3 is formed on the wafer 34.
6 is exposed. In this state, it is confirmed whether transfer of all stripes 24 to 30 on the mask 22 is completed (step S14).

Here, since the transfer of the pattern of the stripes 26 to 30 has not been completed, the mask stage 14 is started to be accelerated by the acceleration + A in the left direction perpendicular to the arrow 42 (step S16). As a result, the central axis of the electron optical system moves on the mask 22 at the irradiation end position 42d.
To move in the direction of arrow 50 while gradually increasing the speed.

Next, the deceleration of the mask stage 14 is started (step S18). Here, when the central axis reaches an intermediate point 50a between the irradiation end position 42d of the stripe 24 and the irradiation start position 44a of the stripe 26, deceleration at acceleration -A is started. As a result, the central axis of the electron optical system moves in the direction of arrow 50 while gradually reducing the speed.

When the irradiation start position 44a of the stripe 26 is reached, the scanning speed becomes 0, so the deceleration is ended here. As a result, the irradiation start position 4 of the stripe 26
The mask 22 is moved to 4a (step S2). Since the width of each of the stripes 24 and 26 is 26 mm,
The distance traveled from stripe 24 to stripe 26 is 2
It is 6 mm.

Again, steps S4 to S12 are repeated for the stripe 26. That is, on the stripe 26,
The mask stage 14 is scanned so that the central axis of the electron optical system moves in the direction of the arrow 44. During this time, the mask stage 14 is accelerated by acceleration + A while the central axis is from the irradiation start position 44a to the acceleration end position 44b, and is accelerated from the acceleration end position 44b to the deceleration start position 44c, as in the case of the pattern transfer of the stripe 24. During the period, the acceleration is set to 0 and scanning is performed at a constant speed. When the central axis reaches the deceleration start position 44c, the mask stage 14 is accelerated by the acceleration -A.
Deceleration is started, and the scanning speed is 0 at the irradiation end position 44d.
And the deceleration ends. During this period, the electron beam 4 is constantly applied.

Next, steps S16 and S18 are repeated to move to the irradiation start position 46a of the stripe 28.

In this way, the pattern is transferred to the wafer 34 for all of the four stripes 24 to 30 formed on the mask 22. After that, it is confirmed whether or not all stripes 24 to 30 have been transferred (step S14), and if the transfer is completed, the transfer of the pattern is ended.

The width of the major strut is 10 mm.
Therefore, the moving distance between the stripe 26 and the stripe 28 is 36 mm. The moving distance between the stripe 28 and the stripe 30 is 26 mm. Further, the moving distance from the stripe 30 to the stripe 24 is 88 m.
m.

FIG. 4 is a graph showing the relationship between the acceleration of the mask stage 14 and the elapsed time when exposure is performed in this embodiment. FIG. 4A shows the length of each stripe 24-30. 4B shows a case where the mask stage 14 is scanned in a direction parallel to the direction, and FIG. 4B shows a case where the mask stage 14 is scanned in a direction perpendicular to the longitudinal direction of each stripe 24-30. Show. Note that FIG.
4A and 4B, the vertical axis represents acceleration and the horizontal axis represents time.

Irradiation start position 4 of each stripe 24-30
Mask stage 1 so that the central axis comes to 2a to 48a
When 4 is set, the acceleration of the mask stage 14 is 0. From this state, as shown at time a in FIG.
4 acceleration is started. Acceleration continues until time b,
At time b, the acceleration ends. At this point, the central axis is at the acceleration end positions 42b to 48b of the mask 22. In this state, the acceleration is set to 0 and the uniform velocity motion is continued until time c.
At the time point of time c, the central axis is at the deceleration start positions 42c to 48c of the mask 22. From time c, deceleration at acceleration-A is started. The deceleration is continued until time d, and the deceleration ends at time d. At this point, the speed of the mask stage 14 is zero. The central axis is located at the deceleration end positions 42d to 48d of the mask 22. In this embodiment, the time T from the acceleration start time a to the deceleration end time d
During 1, the irradiation of the electron beam 4 is performed.

As shown at time e in FIG. 4B,
When moving from the deceleration end position of one stripe to the acceleration start position of the adjacent stripe, the mask stage 14 is accelerated by acceleration + A from the state of acceleration 0. Acceleration continues until time f. At time f, the central axis is at the midpoints 50a to 56a between the deceleration end position of the stripe and the acceleration start position of the next moving stripe.
At time f, deceleration starts at acceleration -A. The deceleration continues until time g. At time g, the scanning speed of the mask stage 14 is 0. Also, the central axis is
The acceleration start positions 42a to 48a on the mask 22 are present.

As described above, according to this embodiment, even when the mask stage 14 is being accelerated or decelerated,
The pattern can be transferred by irradiating the electron beam 4. Therefore, the waiting time for acceleration and deceleration can be effectively used for the irradiation time, and the throughput can be improved.

FIG. 5 shows a pattern obtained by using the EPL exposure apparatus 100.
When the turn is transferred and when the conventional exposure device is used
Acceleration in each case of pattern transfer
It is a graph which shows the relationship between a degree and throughput. Figure 5
The plot using □ is the EPL exposure apparatus 10
In the case of 0, the plot using ◯ is the conventional exposure apparatus.
Is the case. Note that in FIG. 5, the vertical axis represents one hour.
Is the number of processed sheets, and the horizontal axis is acceleration. Also, this
Here, the exposure condition is that the size of the angle of view is 20 m across.
m, length 25 mm, wafer size 300 nmφ
However, the number of angles of view is set to 106 per wafer.
It The current density is 0.16 A / cm ^TwoAnd cashier
Stroke sensitivity is 5 μC / cm^TwoI am trying.

As shown in FIG. 5, when the acceleration is the same, the throughput is higher when the electron beam exposure apparatus 100 is used. In particular, when the acceleration is small and the two are compared, the throughput is significantly larger when the EPL exposure apparatus 100 is used. Therefore,
According to this embodiment, the ratio of the waiting time to the entire exposure processing time can be suppressed as compared with the conventional exposure method, and the throughput can be improved.

Further, as shown in FIG. 5, the acceleration required to process the same number of sheets is determined by the electron beam exposure apparatus 100.
Is smaller when is used. For example, in order to process 35 sheets / hour, an acceleration of 5G is required in the case of the conventional method, whereas an acceleration of 1G is sufficient if the electron beam exposure apparatus 100 is used. Therefore, the exposure can be performed while suppressing the acceleration, and the distortion of the mask and the vibration of the apparatus due to the rapid acceleration can be suppressed. This makes it possible to accurately transfer a fine pattern, and
Since it is not necessary to take measures against vibrations in the exposure apparatus, the apparatus can be simplified.

Since the electron beam is emitted during acceleration or deceleration, the scanning of the mask stage 14 may be started or ended while the central axis is on the pattern formed on the mask. it can. Therefore, it is not necessary to enlarge the mask stage 14 by the scanning distance during acceleration or deceleration. Therefore, the size of the exposure apparatus can be reduced by reducing the size of the mask stage 14, and the exposure apparatus can be manufactured at low cost.

Further, in this embodiment, the EPL exposure apparatus 100 is equipped with the electron gun 2 and is
Transfer the pattern. As a result, deterioration of the resolution of the mask pattern can be suppressed by the diffraction effect, and high resolution performance can be achieved.

Further, in this embodiment, the EPL exposure apparatus 100 uses the image forming optical system 16. As a result, the distance between the mask and the wafer can be increased, and the device design can be facilitated. A reduction optical system was used as the imaging optical system 16. Therefore, the maximum pattern size on the mask can be increased, and the mask can be easily manufactured.

Further, in the present invention, the position control means 74 controls the scanning speed of each stage 14, 20 by the mask stage operating means 70 and the wafer stage operating means 72 by the method of feedback and feedforward. Further, the response speed of each stage operating means 70, 72 to these control signals is improved.
Therefore, even during exposure during acceleration / deceleration, highly accurate exposure can be performed.

In this embodiment, EPL is used.
Although the exposure apparatus 100 is used for the description, the present invention is not limited to this, and a scanner employing a scanning method or another exposure apparatus may be used. For example, the EPL exposure apparatus 100
In order to achieve high resolution performance, pattern transfer is performed using an electron beam, but the present invention is not limited to an exposure apparatus that uses an electron beam. Also,
The EPL exposure apparatus 100 has an imaging optical system 16 which is a reduction optical system as an optical system. However, the device is not limited to such an optical system.

In addition, in this embodiment, the mask 22 is divided into four stripes 24 to 30 to form a pattern. However, the number of stripes is not limited to four, and the stripe pattern need not be formed in this way.

In this embodiment, the electron beam is started at the same time as the acceleration is started from the state where the mask stage is moved so that the central axis comes to the acceleration start position of the mask. However, it is not limited to this,
The irradiation of the electron beam may be started from a state where the acceleration is started and the mask stage reaches a certain speed. At the same time as the deceleration was completed, the electron beam irradiation was completed. However, the present invention is not limited to this, and the deceleration may be continued to some extent after the irradiation of the electron beam is finished in a state where the speed is decelerated to a certain extent. In addition,
In such a case, it is necessary to provide a portion where a pattern is not formed by the scanning distance in which the central axis moves on the mask while the electron beam is not irradiated.

Further, here, the case where the acceleration / deceleration is performed at the constant acceleration + A or −A has been described. However, the acceleration is not limited to be constant, and the acceleration may change with time.

Further, here, the EPL exposure apparatus 100 including the mask stage operating means 70, the wafer stage operating means 72 and the position control means 74 has been described, but the present invention is not limited to those including these means. .

In the present invention, the original plate corresponds to the mask 22 of the embodiment, and the sample corresponds to the wafer. Further, the original stage mounting table corresponds to, for example, the mask stage 14 of the embodiment, and the sample mounting table includes
The wafer stage is applicable. Further, in the present invention, for example, the electron gun 2 of the embodiment corresponds to the radiation source, and the imaging optical system 16 corresponds to the projection optical system.

[0078]

As described above, according to the present invention, the pattern can be transferred by irradiating the charged particle beam or the electromagnetic wave even when the original mounting table is being accelerated or decelerated. Therefore, it is possible to omit the waiting time for accelerating or decelerating the original plate, shortening the exposure processing time and improving the throughput.

Further, according to the present invention, it is possible to obtain a certain throughput even when the acceleration is small, so that it is possible to perform exposure while suppressing the acceleration. Therefore,
It is possible to suppress the distortion of the original plate and the vibration of the device due to the rapid acceleration, and it is possible to transfer the pattern more accurately. Further, since it is not necessary to take measures for vibration prevention in the exposure apparatus, the exposure apparatus can be simplified and manufactured at low cost.

Further, according to the present invention, the charged particle beam or the electromagnetic wave is applied to the original plate even during acceleration or deceleration. Therefore, unlike the conventional case, it is not necessary to enlarge the mask stage by the scanning distance while the charged particle beam during acceleration and deceleration is not irradiated. Therefore, the exposure apparatus can be downsized, and the exposure apparatus can be manufactured at a low price.

Further, in the present invention, in the optical system having the optical system for forming an image of charged particles or electromagnetic waves on the sample, the distance between the original plate and the sample table can be set large, and the device design Can be facilitated.

Further, in the present invention, when the optical system is a reduction optical system, the pattern on the mask can be reduced and projected. Therefore, the minimum pattern size of the mask can be increased, and the mask can be easily manufactured.

Further, in the present invention, when the electron beam is used as the charged particle beam, the electron beam having an extremely short wavelength is used, so that the deterioration of the resolution of the mask pattern image due to the diffraction effect can be suppressed. . Therefore, high resolution performance can be achieved and accurate transfer of a fine pattern can be performed.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an EPL exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic top view showing a mask 22 used in the EPL exposure apparatus in the embodiment of the present invention.

FIG. 3 is a flowchart for explaining an exposure method according to the embodiment of the present invention.

FIG. 4 is a graph showing the relationship between the acceleration of the mask stage and the elapsed time when exposure is performed in the embodiment of the present invention.

FIG. 5 shows the relationship between acceleration and throughput when a pattern is transferred using the EPL exposure apparatus according to the embodiment of the present invention and when a pattern is transferred using a conventional exposure apparatus. It is a graph shown.

FIG. 6 is a schematic diagram showing a relative position where a central axis of an electron optical system moves on a mask in a conventional EPL exposure apparatus.

FIG. 7 is a graph showing the relationship between the acceleration of the mask scanning speed and the elapsed time in the conventional EPL exposure apparatus.

FIG. 8 shows a wafer 1 in a conventional EPL exposure apparatus.
It is a graph which shows the relationship between the exposure time per sheet and acceleration.

FIG. 9 shows acceleration and acceleration in a conventional EPL exposure apparatus,
It is a graph which shows the relationship with throughput.

[Explanation of symbols]

100 electron beam exposure apparatus 2 electron gun 4 electron beam 6 anode 8 molding diaphragm 10 illumination optical system 12 illumination deflector 14 mask stage 16 imaging optical system 18 objective deflector 20 wafer stage 22 masks 24 to 30 stripes 32 major struts 34 wafers 36 Transfer Pattern 38 Electron Beam Deflection Direction 40 Mask Stage Scanning Direction 42 to 48, 50 to 56 Scanning Direction 42a, 44a, 46a, 48a of Central Axis of Electron Optical System Stripe Irradiation Start Positions 42b, 44b, 46b, 48b Acceleration end position 42c, 44c, 46c, 48c Deceleration start position 42d, 44d, 46d, 48d Stripe irradiation end position 60 Wafer stage scanning direction 62 Electron beam scanning direction 70 Mask stage operating means 72 Wafer stage operating means 74 Position control means

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Claims (8)

[Claims] 1. Scanning an original plate on which a pattern is formed,
In an exposure method of transferring a pattern to a sample by irradiating the original with a charged particle beam or an electromagnetic wave, acceleration in the scanning direction of the original is started, and during the acceleration of the original, a charged particle beam or an electromagnetic wave An exposure method characterized by starting irradiation. 2. The original plate is started to be irradiated with a charged particle beam or an electromagnetic wave, and then, while being irradiated with a charged particle beam or an electromagnetic wave, deceleration in the scanning direction of the original plate is started. Item 2. The exposure method according to Item 1. 3. A pattern-formed original plate is scanned,
In an exposure method of transferring a pattern to a sample by irradiating the original plate with a charged particle beam or an electromagnetic wave, the original plate is irradiated with a charged particle beam or an electromagnetic wave, and a deceleration in a scanning direction of the original plate is performed. An exposure method comprising starting. 4. The exposure method according to claim 1, wherein an electron beam is used as the charged particle beam. 5. A radiation source capable of emitting a charged particle beam or an electromagnetic wave, an original placement table on which a patterned original is placed and can be scanned, and a sample can be placed. A sample mounting table, wherein the radiation source is configured to accelerate and / or accelerate the scanning speed of the original mounting table.
Alternatively, the exposure apparatus is capable of irradiating the original plate with a charged particle beam or an electromagnetic wave during deceleration. 6. The exposure apparatus according to claim 5, further comprising an optical system for forming an image of the charged particle beam or the electromagnetic wave on the sample. 7. The exposure apparatus according to claim 6, wherein the optical system is a projection optical system. 8. The exposure apparatus according to claim 5, wherein the charged particle beam is an electron beam.