JP2000021746A - Charged particle beam split projection transfer apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To narrow the effective view field of an electron lens in a charged particle beam split projection transfer apparatus. SOLUTION: A one-chip unit in a reticle is divided into a plurality of stripes 1 and they are further divided into a plurality of sub-fields 2. While the reticle is being shifted, a charged particle beam is scanned at almost the right angles with respect to the shifting direction of the reticle, and split projection exposure is carried out for each sub-field 2. Here, scanning by the charged particle beam is made in the same direction, as indicated by a solidtire arrow for each row. The positions of the sub-fields exposed are made linear in a stationary state, so that a highly accurate region (effective view field) in electron lens is concentrated on a narrow region along this linear part and the electron lens system design is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for transferring a pattern on a transfer object such as a reticle onto a transfer body such as a wafer by using a charged particle beam such as an electron beam. The upper pattern is divided into a plurality of stripes, each stripe is further divided into a plurality of subfields, and while the object to be transferred is moved on the stage, the charged particle beam is deflected in a direction substantially perpendicular to the moving direction. The present invention relates to a charged particle beam splitting projection transfer apparatus which scans a subfield, and divides a pattern of a transfer target body divided into subfields into transfer bodies for each subfield and performs projection transfer.

[0002]

2. Description of the Related Art The exposure method of a conventional charged particle beam exposure apparatus is roughly classified into the following three types. (1) Spot beam exposure method (2) Variable shaping exposure method (3) Block exposure method These exposure methods have a very superior resolution in comparison with the conventional batch transfer method using light, but have a large throughput. Was inferior. In particular, in the exposure methods (1) and (2), the exposure is performed by tracing a pattern with a very small spot diameter or a rectangular beam, so that the throughput is limited. The block exposure method (3) is a method developed to improve the throughput. The fixed pattern is masked and the portion is exposed at a time to improve the throughput. However, even in this method, the number of patterns to be masked is limited, so that the variable shaping exposure method must be used in combination, and the throughput has not been improved as expected.

As described above, in order to improve throughput, which is a drawback of the conventional charged particle beam exposure apparatus, development of a division projection transfer type exposure apparatus for projecting and exposing a part of a reticle onto a sample at a time has been advanced. ing.

FIG. 10 shows an exposure apparatus of this division projection transfer system.
And FIG. FIG. 10 is a diagram showing a unit of division exposure. First, the transfer body (usually a wafer)
A plurality of chips are formed thereon, and the chips are further divided into stripes, and the stripes are divided into subfields. An object to be transferred, such as a reticle, is similarly divided.

In a divided projection exposure apparatus, exposure is usually performed by a method as shown in FIG. First, the reticle stage and the wafer stage move at a constant speed along the center of the corresponding stripe at a speed according to the reduction ratio. The electron beam illuminates a subfield on the reticle, and a pattern formed on the reticle is projected and exposed on a sample by a projection optical system.

Then, the electron beam is deflected in a direction substantially perpendicular to the direction of travel of the reticle stage, and the subfields arranged in a row are sequentially subjected to projection exposure. When the projection exposure of one row of subfields is completed, the projection exposure of the next row of subfields is started. At this time, the deflection direction of the electron beam is reversed as shown in FIG. Is performed to increase the throughput.

Since the exposure is performed by such a method, compared with a conventional charged particle beam exposure apparatus, the sub-field region is exposed at a time and the reticle has all the patterns to be exposed. The throughput can be improved.

The reticle used in this exposure method is divided into a subfield portion (pattern portion) and a beam portion (hereinafter referred to as a strut) around the subfield portion, unlike an exposure device using light. The beam portion is provided for the purpose of maintaining the strength of the reticle itself and for selecting only a subfield to be reliably exposed to the illumination beam.

[0009]

However, these conventional divided projection exposure apparatuses have the following problems. That is, as described above, electron beam deflection (scanning) for sequentially projecting and exposing each subfield.
Is performed in a direction substantially perpendicular to the direction of travel of the reticle stage, and the direction of travel of the scanning is reverse for each row of subfields. Therefore, when the position where each subfield is exposed is viewed with reference to the electron lens, an X-shape is drawn.

FIG. 12 shows this state. In FIG. 12, 2a to 2e, 2a 'to 2e' indicate positions where each subfield is exposed, 3 indicates the field of view of the electronic lens, and 3 'indicates the effective field of view of the electronic lens. X and Y indicate the X and Y axes of the projection exposure optical system, respectively. It is assumed that the reticle stage is moving in the negative Y-axis direction.

In FIG. 12, first, a subfield 2a at the end of one line (hereinafter referred to as a left end) is exposed. Next, the subfield 2b on the right side is exposed. At this timing, the position of the subfield 2b is slightly shifted to the negative side in the Y-axis direction because the reticle stage is slightly advanced in the negative Y-axis direction. ing. Therefore, in order to irradiate the electron beam to the position where the subfield 2b exists at that time, the deflection in the Y-axis direction must be performed simultaneously with the deflection in the X-axis direction.

Similarly, at the timing when the subfield 2c is exposed, the reticle stage is further advanced in the negative Y-axis direction, so that the position where the subfield 2c exists is further shifted to the negative side in the Y-axis direction. In this manner, when sequentially performing the exposure in the subfields 2a to 2e, the electron beam is scanned in the direction indicated by the broken line to the lower right by the X-axis direction deflection and the Y-axis direction deflection. Become.

In this way, when the projection exposure of one row of subfields is completed and the projection exposure of the next row is performed, the scanning direction of the electron beam is reversed as described above. That is, the subfield 2e 'at the right end
To the leftmost subfield 2a '. The scanning direction at this time is as shown in FIG.
As shown in FIG. 5, the direction is indicated by a broken line falling left.

As described above, the scanning along the dashed line declining to the right and the scanning along the dashed line declining to the left are performed alternately, so that the electron lens has an effective field of view 3 'large enough to cover this range. Must have. Since this range is considerably wide, an electronic lens having a required accuracy over a wide range is required, and there is a problem that the design of the electronic lens becomes difficult.

Further, as described above, in order to sequentially project and expose subfields, deflection in the X-axis direction and deflection in the Y-axis direction must be performed simultaneously. However, there is also a problem that transfer accuracy is deteriorated, and control for removing complex errors is required.

Further, in order to perform deflection, the deflector is provided with D
It is necessary to supply a voltage via the / A converter. D / A
The converter requires high speed, linearity, and high resolution, but the conventional D / A conversion method requires a long conversion time to achieve high resolution, and as a result, the scanning speed of the electron beam is limited. However, there is a problem that the throughput of exposure transfer cannot be increased. In addition, the higher the resolution of the D / A converter, the more difficult it is to secure linearity, and there is also a problem that a single D / A converter has a limit in the range in which it can deflect.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a charged particle beam splitting projection transfer apparatus capable of narrowing the effective field of view of an electron lens, without performing deflection in a plurality of directions. It is an object of the present invention to provide a charged particle beam splitting projection transfer device capable of scanning charged particles on a subfield and a charged particle beam splitting projection transfer device capable of scanning charged particles on a subfield at high speed.

[0018]

A first means for solving the above-mentioned problem is to divide a pattern on an object to be transferred into a plurality of stripes, and further divide each stripe into a plurality of subfields. While moving the transfer body on the stage, scan the subfield by deflecting the charged particle beam in a direction substantially perpendicular to the movement direction, and transfer the pattern of the transfer target divided into subfields for each subfield What is claimed is: 1. A charged particle beam division projection transfer apparatus for projecting and transferring by dividing into a body, wherein a position of a subfield to be exposed is linear and fixed. An apparatus (claim 1).

In this means, the position of the subfield to be exposed is not on the X-shape but on one straight line.
It is intended to be fixed. Therefore, the electronic lens may have the required accuracy near the straight line, and thus the design of the electronic lens becomes easy.

Further, as will be described later, by making the polarization direction of the deflector coincide with the direction of this straight line, scanning can be performed only by deflection in one direction. No problem such as occurrence of a problem occurs.

Further, since the position of the subfield to be exposed is fixed, as will be described later, the deflection amount is set to a stepwise fixed value, and fine adjustment may be added thereto. Therefore, the D / A converter attached to the deflector can reduce the number of bits, thereby improving linearity and conversion speed. Accordingly, the scanning speed of the charged particle beam is improved, so that the exposure transfer throughput can be improved.

In addition, since the position of the subfield to be exposed is fixed, the correction value to be applied to the electron lens system becomes a fixed value and can be prepared in advance, as described later. Therefore, it is possible to finely correct the error factor of the electron lens system.

A second means for solving the above-mentioned problem is:
The first means, wherein the straight line passes through a substantially center of the electron lens (Claim 2).

By doing so, the characteristics of the electronic lens can be made symmetrical in the vertical and horizontal directions. In addition, the most accurate central portion of the electron lens can be used for exposure transfer, and a highly accurate charged particle beam division projection transfer device can be obtained.

A third means for solving the above-mentioned problem is:
The first means or the second means, wherein the scanning direction of the subfield by the charged particle beam is set to one direction, so that the position of the subfield to be exposed is in one linear shape. Features (Claim 3)
It is.

In this means, the scanning direction of the subfield by the charged particle beam is not alternately reversed, but the scanning is always performed from one direction. Therefore, the position of the subfield to be exposed is not on the X-shape but on the straight line of the lower right or lower left. Therefore, although the throughput is reduced, the first method is used in a simple manner.
Means or the second means can be realized.

A fourth means for solving the above-mentioned problem is:
The first means to the third means, wherein a moving direction of the stripe and a direction of the straight line are perpendicular to each other (claim 4).

Usually, in a charged particle beam division projection transfer apparatus, the moving direction of the stripe is set to the Y-axis direction, and the direction perpendicular to the Y-axis direction is set to the X-axis direction.
It is arranged with respect to the axis. Therefore, according to this means,
An X-axis direction deflector may be used as a deflector for scanning, and there is no need to provide a special deflector. Since the deflectors in the Y-axis direction do not need to be used for scanning, a composite error does not occur between the deflectors.

A fifth means for solving the above problem is as follows.
The fourth means, wherein the means for making the direction of movement of the stripe and the direction of the straight line perpendicular to each other is means for arranging subfields in a direction not perpendicular to the direction of movement of the stripe. (Claim 5).

[0030] The moving speed of the reticle stage Vs, when the scanning speed of the charged particle beam Vb, the arrangement direction of the row of sub-fields, from the moving direction perpendicular to the direction of the reticle stage tan ^- (Vs / Vb) only Try to tilt. By such a simple means, it is possible to make the moving direction of the stripe perpendicular to the direction of the straight line.

A sixth means for solving the above-mentioned problem is as follows.
In any one of the first means to the fifth means, a deflector of the illumination optical system is provided such that a deflection direction coincides with the direction of the straight line. 6).

In this means, the scanning of the charged particle beam can be performed by the one-way deflector, so that the compound error between the two-way deflectors in the prior art is eliminated, and the deterioration of accuracy is prevented. be able to.

A seventh means for solving the above-mentioned problem is as follows.
In any one of the first means to the sixth means, the deflection angle of the deflector is a plurality of fixed angles, and further includes a selection means for selecting any one of the plurality of fixed angles. A deflector for angle fine adjustment is provided separately (claim 7).

In this means, the deflection angle of the deflector is
There are a plurality of fixed angles corresponding to the positions of the subfields to be exposed. Therefore, the voltage to be applied to the deflector can be selected by means for selecting one of them, and the response can be quickened as compared with the one using the conventional D / A converter. Fine adjustment of the deflection angle is performed by a separately provided deflector for fine adjustment of the deflection angle. However, since the deflection range may be narrow, the number of bits of the D / A converter is small and the response can be quickened. . Therefore, the scanning speed of the charged particle beam can be increased as a whole,
A charged particle beam division projection transfer device having a high throughput can be obtained.

Eighth means for solving the above-mentioned problem is:
A voltage setter for generating a voltage corresponding to a plurality of fixed deflection angles, and a variable voltage for generating a voltage corresponding to a deflection angle for fine adjustment. And a voltage corresponding to the sum of the voltage setter and the variable voltage generator is applied to the deflector.

This means is obtained by substituting the deflector and the deflector for finely adjusting the deflection angle in the seventh means with one deflector, and has the same operation and effect as the seventh means.

A ninth means for solving the above problems is as follows:
The seventh means or the eighth means, wherein a correction parameter for an electron lens is prepared for each of the fixed deflection angles,
A correction parameter corresponding to each projection transfer corresponding to each fixed deflection angle is set in the electronic lens system (claim 9).

The correction of various electron lenses must be performed in accordance with the deflection angle. In the seventh means and the eighth means, since the deflection angle is fixed, predetermined correction is made for these. Correction parameters can be prepared. Then, by setting a corresponding correction parameter in the electron lens system for each projection transfer corresponding to each fixed deflection angle, it is possible to finely correct the error factor.

A tenth means for solving the above-mentioned problem is that, among the third means to the ninth means, the sub-field to be exposed is set by setting the scanning direction of the sub-field by the charged particle beam to one direction. The position of the field is arranged in one straight line, and a device for resetting the voltage applied to the deflector to 0 V or a positive initial voltage at the start of scanning of a row of subfields is provided. This is a feature (claim 10).

In this means, the voltage applied to the deflector is reset (usually reset to 0 V at the start of scanning of the subfield (when exposing the first subfield of a row of subfields). It is sufficient to reset the voltage to the initial voltage, not limited to the case of resetting to 0 V). As the scanning progresses, the voltage applied to the deflector gradually increases, and reaches a maximum when exposing and transferring the last subfield in a row. When this is returned to the initial condition, a large back electromotive force is generated in the deflection coil, and accordingly, a reverse current flows in the deflection coil. In a normal state, it takes time for the back electromotive force and the reverse current to reach the initial values.However, the voltage applied to the deflector is reset by means such as short-circuiting the coil of the deflector to return to the initial condition. Time can be reduced. Therefore, the scanning speed can be increased as a whole, and a charged particle beam division projection transfer device having a high throughput can be obtained.

An eleventh means for solving the above-mentioned problem is any one of the first means to the tenth means, wherein a circuit for short-circuiting a reverse current flowing through the deflection coil is provided. (Claim 11).

According to this means, the reverse current generated when the voltage applied to the deflector is returned to the initial state is short-circuited, and D / D
By bypassing the A converter and the adder, the voltage of the deflector can be returned to the initial state early. Therefore, the scanning speed can be increased as a whole, and a charged particle beam division projection transfer device having a high throughput can be obtained.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a subfield scanning method in an example of an embodiment (electron beam splitting projection transfer apparatus) of the present invention, and FIG. 2 is a diagram showing each row in a case where the subfield scanning method shown in FIG. 1 is employed. FIG. 9 is a diagram showing a position where a subfield is exposed and transferred.
In these figures, 1 indicates one stripe, 2 indicates a subfield, and one column of the subfield is 2
Indicated by a to 2e. 3 is the field of view of the electron lens,
The negative direction of the Y axis is defined as the traveling direction of the reticle stage, and the X axis is defined as the direction orthogonal to the direction.

The solid arrows in FIG. 1 indicate the order in which the electron beam is scanned for exposure and transfer. That is, the exposure transfer is performed by scanning the subfields of each column in the same direction.

FIG. 2 shows this in the field of view 3 of the electron lens. First, it is at the end of the line (the left end)
Subfield 2a is exposed. Next, the subfield 2b on the right side is exposed. At this timing, the position of the subfield 2b is slightly shifted to the negative side in the Y-axis direction because the reticle stage is slightly advanced in the negative Y-axis direction. ing. Therefore, in order to irradiate the electron beam to the position where the subfield 2b exists at that time, the deflection in the Y-axis direction must be performed simultaneously with the deflection in the X-axis direction.

Similarly, at the timing when the subfield 2c is exposed, the reticle stage is further advanced in the negative direction of the Y axis, so that the position where the subfield 2c exists is further shifted to the negative side in the Y axis direction. In this manner, when sequentially performing the exposure in the subfields 2a to 2e, the electron beam is scanned in the direction indicated by the broken line to the lower right by the X-axis direction deflection and the Y-axis direction deflection. Become. This operation is performed according to the conventional method shown in FIG.
This is the same as the first scanning operation.

However, in this embodiment, the scanning of the next row is performed in the same direction.
The position where the subfields of the next column are exposed and transferred is
At positions 2a to 2e. In other words, the positions where all the subfields are exposed and transferred are the positions indicated by 2a to 2e in FIG. 2, that is, the fixed positions on the line indicated by the broken line sloping to the right, and the X-shape is used as in the conventional example. There is no drawing.

Therefore, the electronic lens may be designed so that accuracy can be obtained in a narrow range along this straight line, and the design of the electronic lens becomes easy. In particular, as shown in FIG. 2, if this straight line passes through the center of the electronic lens, a portion having good performance of the electronic lens can be used most effectively. Further, if the deflection direction of the deflector is set to the direction along this straight line, it is not necessary to simultaneously deflect in the X-axis direction and the Y-axis direction unlike the conventional example. This eliminates the problem of the occurrence of the error, and eliminates the need to perform complicated correction to prevent these complex errors.

FIG. 3 is a diagram showing a subfield scanning method according to another embodiment of the present invention, and FIG.
FIG. 9 is a diagram showing positions where each row of subfields is exposed and transferred when the subfield scanning method shown in FIG. 3 and FIG. 4 correspond to FIGS.
The same components as those in the above are shown.

In FIG. 3, the rows of subfield 2 are not arranged in a direction perpendicular to the direction of travel of the reticle stage, but are arranged diagonally. That is, when the moving speed of the reticle stage Vs, and the scanning speed of the charged particle beam Vb, the arrangement direction of the row of sub-fields, tan than the movement direction perpendicular to the direction of the reticle stage ^-
(Vs / Vb).

FIG. 4 shows the position at which the subfield thus arranged is exposed and transferred in the field of view 3 of the electron lens. First, the subfield 2a at the end of the line (the left end) is exposed. An adjustment is made so that the exposure position is on the X axis. Next, the subfield 2b on the right side is exposed, and at that timing, the reticle stage is slightly advanced in the Y-axis negative direction. However, since the subfield 2b is located behind the subfield 2a, the subfield 2b is
b comes to be on the X axis. That is, as described above, such a relationship can be established when the arrangement direction of the subfield columns is inclined by tan ⁻ (Vs / Vb) from the direction perpendicular to the direction of movement of the reticle stage. Similarly, at the timing when the subfield 2c is exposed and transferred, the subfield 2c is on the X axis.
The same applies to d and 2e.

In this manner, by shifting the arrangement direction of the subfield rows and making the scanning direction of the electron beam one direction, the position where one row of the subfields is exposed and transferred is perpendicular to the traveling direction of the reticle stage. It can be on a straight line in the direction, especially on the X axis. With this configuration, a commonly provided deflector in the X-axis direction can be used as a deflector used for scanning an electron beam. Therefore, as shown in FIG.
There is no need to use both the axial deflector and the Y-axis deflector and to provide a deflector oriented in a special direction.

When each subfield is exposed and transferred at the position shown in FIGS. 2 and 4, the exposure position of each subfield is fixed. Therefore, the main deflection by the deflector can be switched stepwise so that the electron beam is irradiated to the positions 2a to 2e in FIGS. 2 and 4, and a deflection for fine adjustment of the position is added thereto. This eliminates the need for a deflector D / A converter consisting of a large number of bits, which is conventionally required.

FIG. 5 shows an example of a deflector and its control circuit used in the embodiment of the present invention. In FIG. 5, 4 is a fixed voltage switching circuit, 5 is a deflector for fixing, 6 is a D / A converter for offset, 7 is a D / A converter for synchronization, 8
Is an adder, and 9 is a fine adjustment deflector. FIG. 5 shows an example in which a fixed deflector 5 for performing main deflection and a fine adjustment deflector 9 for performing fine adjustment are separately provided.

The fixed voltage switching circuit 4 generates a voltage enough to deflect the electron beam at the positions 2a to 2e in FIGS. 2 and 4, and supplies the voltage to the fixing deflector 4. That is,
In the figure, when any one of deflection 1 to deflection 5 is selected and inputted, a corresponding fixed voltage is generated.

The offset D / A converter 6 receives, as an offset value, an input for canceling an error due to a change in the attitude of the reticle, performs D / A conversion on the input, and outputs the result to the adder 8. The synchronization D / A converter 7 receives a deflection command for correcting a deviation in synchronization between the reticle stage and the wafer stage, a variation in the speed of the reticle stage, and the like, and D / A converts the signal to output to the adder 8. The adder 8 adds these and supplies the result to the fine adjustment deflector 9. The offset D / A converter 6 and the synchronization D / A converter 7 as one D / A converter,
After digitally adding the offset value and deflection command,
The D / A converter may convert the voltage into an analog voltage and supply the analog voltage to the fine adjustment deflector 9.

Since the offset D / A converter 6 and the synchronization D / A converter 7 are for fine adjustment, their output ranges are small, and thus the resolution is low. Therefore, the number of input bits is small and the time required for D / A conversion is shortened, so that the scanning speed of the electron beam can be increased.

FIG. 6 shows another example of the deflector used in the embodiment of the present invention and its control circuit. In FIG. 6, each reference numeral indicates the same component as the component in FIG. FIG. 6 shows a case where the fixing deflector and the fine-tuning deflector in FIG. 5 are combined into one deflector.
The outputs of the fixed voltage switching circuit 4, the offset D / A converter 6, and the synchronization D / A converter 7 are added and supplied to the deflector 10.

The circuits shown in FIGS. 5 and 6 may be provided only in the one-way deflector when the deflection for electron beam scanning is performed by a one-way deflector.
(For the axial direction and the Y-axis direction), it is necessary to provide each deflector.

FIG. 7 shows an example of the output voltage of the fixed voltage switching circuit 4 in FIGS. In FIG. 7, the deflection number 1
2 and FIG. 4 are the voltages at the time of exposing and transferring the subfield 2a.
The voltage at the time of exposing and transferring b, hereinafter, corresponds to the voltage at the time of sequentially transferring up to the subfield 5e up to the polarizing plate number 5. As can be seen from the figure, the amount of deflection is greatest when the deflection is returned from the deflection number 5 to the deflection number 1 in order to draw a subfield in one column and then draw a subfield in the next column. For this reason, in the usual method, the back electromotive force from the deflection coil becomes large, and it takes time to establish it.

As a countermeasure against this, as shown in FIG. 7, when transferring and exposing the first subfield of one column, that is, the subfield 2a, the output voltage of the fixed voltage switching circuit 4 in FIG. Reset the output voltage of the deflector 8 to 0 and return to the exposure transfer of the first subfield of one row (short-circuit the coil of the deflector to prevent back electromotive force) Thus, these output voltages are set to 0. Thereby, the enactment time can be shortened.

FIGS. 8 and 9 show examples of the reset method. 8 and 9, reference numeral 11 denotes a coil of the deflector, 12 denotes a diode, and 13 denotes a switch. FIG. 8 shows a diode 12 connected in parallel with the coil 11 of the deflector.
When a normal deflection voltage is applied, the output from the adder 8 is positive and monotonically increases as shown in FIG. 7, so that the diode 12 is not conducting. At the timing when the output of the adder 8 is returned to 0, the coil 11 of the deflector is
Generates a back electromotive force. Then, the diode 12 conducts and acts so as to short-circuit the current associated with the back electromotive force, so that the back electromotive force quickly decreases to the forward voltage of the diode 12 and converges.

FIG. 9 shows a switch 13 connected in parallel with the coil 11 of the deflector. In this method, the voltage applied to the coil 11 of the deflector is detected, and when the generation of the back electromotive force is detected, the switch 13 is closed by the control circuit. Then, the current caused by the back electromotive force is short-circuited by this switch, and the back electromotive force quickly converges to zero.

In the charged particle beam division projection transfer device,
When the charged particle beam is deflected, the electron lens system must be corrected according to the amount of deflection. In the present embodiment, since the positions where the subfields are exposed and transferred are fixed, predetermined correction parameters can be prepared for these positions. Then, by setting a corresponding correction parameter in the electron lens system for each projection transfer corresponding to each fixed deflection angle, it is possible to finely correct the error factor.

In the above description of the embodiment of the present invention, an electron beam splitting projection transfer apparatus has been described as an example, but the same concept can be applied to any charged particle beam splitting projection transfer apparatus.

[0066]

As described above, according to the first aspect of the present invention, since the position of the subfield to be exposed is linear and fixed, the design of the electron lens can be improved. Becomes easier. Further, the scanning can be performed only by the deflection in one direction, so that a problem such as a complex error between the deflectors does not occur. Also, the speed of the D / A converter attached to the deflector can be increased,
Since the scanning speed of the charged particle beam is improved, the throughput of the exposure transfer can be improved. in addition,
It becomes possible to finely correct the error factor of the electron lens system.

According to the second aspect of the present invention, since the straight line passes substantially through the center of the electronic lens, the characteristics of the electronic lens can be made symmetrical in the vertical and horizontal directions. In addition, the most accurate central portion of the electron lens can be used for exposure transfer, and a highly accurate charged particle beam division projection transfer device can be obtained.

According to the third aspect of the present invention, since the scanning direction of the subfield by the charged particle beam is set to one direction, the invention according to the first or second aspect can be realized by a simple method. .

In the invention according to claim 4, since the moving direction of the stripe and the direction of the straight line are perpendicular to each other, an X-axis direction deflector may be used as a deflector for scanning. There is no need to provide a special deflector.

In the invention according to claim 5, since the subfields are arranged in a direction that is not perpendicular to the moving direction of the stripe, the moving direction of the stripe and the direction of the straight line are perpendicular to each other by simple means. can do.

In the invention according to claim 6, since the deflector of the illumination optical system is provided so that the deflection direction coincides with the direction of the straight line, the charged particle beam is scanned by the one-way deflector. It is possible to eliminate a complex error between the two-direction deflectors and prevent deterioration of accuracy.

In the invention according to claim 7, the deflection angle of the deflector is a plurality of fixed angles, and there is a selecting means for selecting any one of the plurality of fixed angles, and the deflection for fine adjustment of the deflection angle is provided. Since the D / A converter is provided separately, the number of bits of the D / A converter can be reduced, and the response can be accelerated.

The invention according to claim 8 has a voltage setter for generating voltages corresponding to a plurality of fixed deflection angles, and a variable voltage generator for generating a voltage corresponding to a deflection angle for fine adjustment. Since the voltage corresponding to the sum of the voltage setting device and the variable voltage generator is applied to the deflector, the number of bits of the D / A converter can be reduced, and the response can be accelerated.

According to the ninth aspect, a correction parameter for an electron lens is prepared for each fixed deflection angle.
Since the corresponding correction parameter is set in the electronic lens system for each projection transfer corresponding to each fixed deflection angle, it is possible to finely correct the error factor.

According to the tenth aspect of the present invention, since a device for resetting the voltage applied to the deflector to the initial voltage is provided at the time of starting the scanning of one row of subfields, the time for returning the deflection to the initial condition is reduced. The scanning speed can be shortened, and the scanning speed can be increased as a whole.

According to the eleventh aspect of the present invention, since the circuit for short-circuiting the reverse current flowing through the deflection coil is provided, the time for returning the deflection to the initial condition can be shortened, and the scanning speed as a whole can be reduced. Can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram showing a subfield scanning method in an example of an embodiment (an electron beam division projection transfer device) of the present invention.

FIG. 2 is a diagram showing positions where each row of sub-fields is exposed and transferred when the sub-field scanning method shown in FIG. 1 is adopted.

FIG. 3 is a diagram illustrating a subfield scanning method according to another embodiment of the present invention.

FIG. 4 is a diagram showing positions where each row of sub-fields is exposed and transferred when the sub-field scanning method shown in FIG. 3 is adopted.

FIG. 5 is a diagram illustrating an example of a deflector and a control circuit thereof used in the embodiment of the present invention.

FIG. 6 is a diagram showing another example of the deflector and its control circuit used in the embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of an output voltage of a fixed voltage switching circuit.

FIG. 8 is a diagram illustrating an example of a circuit for shorting back electromotive force generated in a deflection coil.

FIG. 9 is a diagram showing another example of a circuit for shorting back electromotive force generated in a deflection coil.

FIG. 10 is a diagram showing a unit of divided exposure in a divided projection transfer system.

FIG. 11 is a view showing an exposure method in a divided projection exposure apparatus.

FIG. 12 is a diagram showing positions where each row of subfields is exposed and transferred in a conventional divided projection exposure method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Stripe 2 ... Subfield 2a-2e ... Subfield arranged in a line 2a'-2e '... Subfield arranged in the next column of 2a-2e 3 ... Field of view of electron lens 3' ... Effectiveness of electron lens Field of view 4 ... Fixed voltage switching circuit 5 ... Fixed deflector 6 ... Offset D / A converter 7 ... Synchronous D / A converter 8 ... Adder 9 ... Fine adjustment deflector 10 ... Deflector 11 ... Deflector Coil 12 ... diode 13 ... switch

Claims (11)

[Claims] 1. A pattern on an object to be transferred is divided into a plurality of stripes, each stripe is further divided into a plurality of subfields, and while the object to be transferred is moved on a stage,
A charged particle that scans a subfield by deflecting a charged particle beam in a direction substantially perpendicular to the moving direction, and divides the pattern of the transfer target body divided into subfields into transfer bodies for each subfield, and performs projection transfer. What is claimed is: 1. A charged particle beam splitting projection transfer apparatus, wherein a position of a subfield to be exposed is linear and fixed. 2. The charged particle beam division projection transfer device according to claim 1, wherein the straight line passes through substantially the center of the electron lens. 3. The apparatus according to claim 1, wherein the scanning direction of the sub-field by the charged particle beam is set to one direction, so that the position of the sub-field to be exposed is in one linear shape. 3. The charged particle beam division projection transfer device according to 2. 4. The charged particle beam split projection transfer according to claim 1, wherein a moving direction of the stripe and a direction of the straight line are perpendicular to each other. apparatus. 5. The apparatus according to claim 4, wherein the means for making the moving direction of the stripe perpendicular to the direction of the straight line is means for arranging the subfields in a direction not perpendicular to the moving direction of the stripe. A charged particle beam division projection transfer device as described in the above. 6. The charged particle according to claim 1, wherein a deflector of the illumination optical system is provided such that a deflection direction coincides with the direction of the straight line. Line division projection transfer device. 7. The deflection angle of the deflector is set to a plurality of fixed angles. The deflector includes a selection unit for selecting any one of the plurality of fixed angles, and a deflector for finely adjusting the deflection angle is separately provided. The charged particle beam division projection transfer device according to any one of claims 1 to 6, characterized in that: 8. A voltage setting device for generating a voltage corresponding to a plurality of fixed deflection angles, and a variable voltage generator for generating a voltage corresponding to a deflection angle for fine adjustment, wherein the voltage setting device and 7. A voltage corresponding to the sum with the variable voltage generator is applied to the deflector.
The charged particle beam division projection transfer device according to any one of the above. 9. An electronic lens correction parameter is prepared for each fixed deflection angle, and a corresponding correction parameter is set in the electron lens system for each projection transfer corresponding to each fixed deflection angle. A charged particle beam division projection transfer device according to claim 7. 10. The apparatus according to claim 3, wherein the scanning is performed by setting the scanning direction of the subfield by the charged particle beam to one direction. Sub-fields are arranged in a straight line, and a device for resetting the voltage applied to the deflector to 0 V or a positive initial voltage at the start of scanning of one row of sub-fields is provided. A charged particle beam division projection transfer device characterized by the above-mentioned. 11. The charged particle beam division projection transfer device according to claim 1, further comprising a circuit for short-circuiting a reverse current flowing in the deflection coil.