JPH10335223A - Electron beam exposure method and system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an electron beam exposure system from deteriorating in throughput by a method wherein either a method where an electron beam is deflected and set for exposure or another method where an electron beam is deflected for exposure without being set at a deflection position where the entire electron beam is shut off is selected basing on pattern data as to each sub-field. SOLUTION: An element electron optical system array 3 comprises sub-arrays A to E each composed of element electron optical systems. When a sub-field composed of sub-array exposure fields where the sub-arrays A to E are formed is subjected to light exposure on a wafer, a pattern region on the wafer where a pattern is drawn basing on pattern data is successively subjected to light exposure by the unit sub-field. At this point, at a deflection position where electron beams are all shut off, a light exposure process is carried out through either a control method where an electron beam is deflected for exposure without being set or another control method where an electron beam is deflected in a certain deflection width and successively set for exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam exposure method and an exposure apparatus therefor, and more particularly, to an electron beam exposure method for pattern writing using a plurality of electron beams for direct wafer writing or mask and reticle exposure. The present invention relates to an exposure apparatus.

[0002]

2. Description of the Related Art An electron beam exposure apparatus includes a point beam type in which a beam is used in the form of a spot, a variable rectangular beam type in which a variable-size rectangular section is used, and a stencil mask having a desired sectional shape using a stencil. There are devices such as molds.

[0003] Point beam electron beam exposure apparatuses are used only for research and development because of their low throughput. The variable rectangular beam type electron beam exposure apparatus has a throughput of one to two orders of magnitude higher than that of the point type electron beam exposure apparatus. However, when exposing a pattern in which a fine pattern of about 0.1 μm is packed with a high degree of integration, the throughput is still high. There are many problems. On the other hand, a stencil mask type electron beam exposure apparatus uses a stencil mask in which a plurality of repeating pattern transmission holes are formed in a portion corresponding to a variable rectangular aperture. Therefore, a stencil mask type electron beam exposure apparatus has a great advantage in exposing a repetitive pattern. However, for a semiconductor circuit requiring a large number of transfer patterns that cannot be accommodated in one stencil mask, a plurality of stencil masks are required. It is necessary to take out one sheet at a time and use it one by one, which requires a time for mask replacement, which causes a problem that the throughput is significantly reduced.

As an apparatus for solving this problem, a sample surface is irradiated with a plurality of electron beams along design coordinates, and the sample surface is scanned by deflecting the plurality of electron beams along design coordinates. In addition, there is a multi-electron beam type exposure apparatus which draws a pattern by individually turning on / off a plurality of electron beams according to a pattern to be drawn. The multi-electron beam type exposure apparatus has a feature that the throughput can be further improved because an arbitrary drawing pattern can be drawn without using a stencil mask.

FIG. 15 shows an outline of a multi-electron beam type exposure apparatus. 501a, 501b and 501c individually emit electron beams
An electron gun that can be turned on / off. 502 is an electron gun 501a, 501
b, 501c is a reduction electron optical system for reducing and projecting a plurality of electron beams onto the wafer 503, and 504 is a deflector for deflecting the plurality of electron beams reduced and projected onto the wafer 503.

A plurality of electron beams from the electron guns 501a, 501b, and 501c are given the same amount of deflection by a deflector 504. Thus, with respect to each beam reference position, each electron beam is deflected by sequentially setting its position on the wafer in accordance with an arrangement having an arrangement interval determined by the minimum deflection width of the deflector 504. And each electron beam
A pattern to be exposed is exposed in different element exposure regions.

FIGS. 15A, 15B, and 15C respectively show an electron gun 501a.
, 501b, and 501c expose the respective element exposure areas to patterns to be exposed according to the same arrangement. For each electron beam, the positions on the array at the same time are (1,1), (1,2) ... (1,16), (2,1), (2,2) ... 2,1
6), (3,1) .. The position is settled and moved, and the beam is irradiated at the position where the pattern (P1, P2, P3) to be exposed exists. The pattern (P1, P2, P3) to be exposed is exposed in each area.

[0008]

In the multi-electron beam type exposure apparatus, since each electron beam simultaneously draws a different pattern, the minimum deflection width of the deflector 504 is set from the minimum line width in the pattern to be exposed. Is done. As the minimum line width becomes finer, the minimum deflection width becomes smaller, and the number of times of performing exposure by stabilizing the position of the electron beam increases. As a result, there is a problem that the throughput is reduced.

[0009]

According to one aspect of the present invention, there is provided an electron beam exposure method for deflecting a plurality of electron beams on a surface to be exposed. The electron beam exposure method of individually controlling and writing a pattern in an element exposure region for each electron beam to sequentially draw a pattern in a subfield composed of the plurality of element exposure regions. Dividing the pattern data of the pattern to be drawn on the subfield as a unit, and setting and exposing the plurality of electron beams with a constant deflection width to expose the subfield as a control method when exposing the subfield. A first control method,
Alternatively, at a deflection position where all of the plurality of electron beams are cut off, one of the second control methods of deflecting and exposing the plurality of electron beams without stabilization is performed based on pattern data for each subfield. And exposing each subfield, and exposing each subfield by a selected control method.

[0010] The selecting step includes a step of calculating and comparing a time for exposing a subfield by the first and second control methods.

In the selecting step, when the number of set positions in the case of exposure by the second control method is equal to or larger than a predetermined value,
The method further comprises the step of selecting the first control method.

An electron beam exposure apparatus according to an embodiment of the present invention is an electron beam exposure apparatus that draws a pattern on a surface to be exposed using a plurality of electron beams. Deflecting means for deflecting, irradiation control means for individually controlling irradiation of each electron beam for each deflection, and deflecting the plurality of electron beams by the deflecting means to draw a pattern in an element exposure area for each electron beam. A pattern is sequentially drawn on a subfield composed of the plurality of element exposure regions, and as a control method for exposing the subfield, the plurality of electron beams are deflected by a constant deflection width and settled by the deflection means. In the first control method in which the exposure is performed, or in the deflection position where all of the plurality of electron beams are blocked by the irradiation control means,
And a control means for selecting and exposing one of the second control methods for exposing by deflecting the electron beam without setting by the deflecting means.

The control means selects a control method based on control data having information on a control method determined based on a pattern exposed in a subfield.

The predetermined control method is characterized in that it is determined based on the result of calculating and comparing the subfield exposure time in the first and second control methods.

When the number of set positions in exposure in the second control mode is equal to or larger than a predetermined value, the first control mode is selected.

The deflecting means has an electrostatic deflector and an electromagnetic deflector, and the control means, when deflecting the plurality of electron beams in the element exposure area, uses the electrostatic deflector. And deflecting the plurality of electron beams from one subfield to the next subfield using the electromagnetic deflector.

One embodiment of the device manufacturing method of the present invention is as follows.
A device is manufactured using the electron beam exposure method or the electron beam exposure apparatus.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) (Description of Components of Electron Beam Exposure Apparatus) FIG. 1 is a schematic view of a main part of an electron beam exposure apparatus according to the present invention.

In FIG. 1, reference numeral 1 denotes an electron gun comprising a cathode 1a, a grid 1b, and an anode 1c.
The electrons emitted from form a crossover image between the grid 1b and the anode 1c. (Hereinafter, this crossover image is referred to as an electron source.)

The electrons emitted from this electron source are converted into substantially parallel electron beams by the illumination electron optical system 2 whose front focal position is at the position of the electron source. A substantially parallel electron beam
The element electron optical system array 3 is illuminated. Lighting electron optical system 2
Is composed of electronic lenses 2a, 2b and 2c. By adjusting the electro-optical power (focal length) of at least two of the electronic lenses 2a, 2b, and 2c, while maintaining the focal position on the electron source side of the illumination electron optical system 2,
The focal length of the illumination electron optical system 2 can be changed. That is, the focal length of the illumination electron optical system 2 can be changed while making the electron beam from the illumination electron optical system 2 substantially parallel.

A substantially parallel electron beam from the illumination electron optical system 2 enters the element electron optical system array 3. The element electron optical system array 3 is formed by two-dimensionally arranging a plurality of element electron optical systems each including an opening, an electron optical system, and a blanking electrode in a direction orthogonal to the optical axis AX. Details of the element electron optical system array 3 will be described later.

The elementary electron optical system array 3 forms a plurality of intermediate images of the electron source, and each intermediate image is formed by a reduced electron optical system 4 described later.
To form an electron source image having substantially the same size on the wafer 5. Where the size of the intermediate image of the electron source, Wm
Sets the size of the electron source to Ws and the focal length of the illumination electron optical system 2.
Assuming that the focal length of each of the electron optical systems of Fi and the elementary electron optical system is Fe, the following formula is used.

Wm = Ws * Fe / Fi Therefore, when the focal length of the illumination electron optical system 2 is changed, the size of the intermediate image of a plurality of electron sources can be changed at the same time.
Therefore, the sizes of a plurality of electron source images on the wafer 5 can be changed at the same time. Further, the focal length and the like of each element electron optical system are set so that the sizes of the electron source images on the wafer 5 are substantially the same. Further, the elementary electron optical system array 3 makes the position of each intermediate image in the optical axis direction different according to the field curvature of the reduction electron optical system 4, and each intermediate image
Thus, aberration generated when the image is reduced and projected on the wafer 5 is corrected in advance.

The reduction electron optical system 4 includes a first projection lens 41 (4
3) and a second projection lens 42 (44). Let the focal length of the first projection lens 41 (43) be f
1. Assuming that the focal length of the second projection lens 42 (44) is f2, the distance between these two lenses is f1 + f2. The object point AX on the optical axis is at the focal position of the first projection lens 41 (43), and its image point is focused on the second projection lens 42 (44). This image is reduced to -f2 / f1. In addition, since the two lens magnetic fields are determined so as to act in opposite directions, theoretically, there are five spherical aberrations, isotropic astigmatism, isotropic coma, field curvature aberration, and axial chromatic aberration. Except for aberrations, other Seidel aberrations and chromatic aberrations related to rotation and magnification are canceled.

Reference numeral 6 denotes a deflector for deflecting a plurality of electron beams from the elementary electron optical system array 3 and deflecting a plurality of electron source images on the wafer 5 by substantially the same deflection width in the X and Y directions. . The deflector 6 includes a main deflector 61 having a large deflection width but a long time until settling, that is, a long settling wait time, and a sub-deflector 62 having a small deflection width but a short settling wait time. Is an electromagnetic deflector, and the sub deflector 62 is an electrostatic deflector.

Reference numeral 7 denotes a dynamic focus coil which corrects a shift in the focus position of the electron source image due to deflection aberration generated when the deflector 6 is operated. This is a dynamic stig coil that corrects the astigmatism of the deflection aberration.

Reference numeral 9 denotes a refocusing coil, which corrects the blurring of the electron beam due to the Coulomb effect when the number of a plurality of electron beams applied to the wafer or the total current applied to the wafer increases. Therefore, the focal position of the reduction electron optical system 4 is adjusted.

Reference numeral 10 denotes a Faraday cup having two single knife edges extending in the X and Y directions, and detects a charge amount of an electron source image formed by an electron beam from the elementary electron optical system.

Reference numeral 11 denotes a θ-Z stage which can move a wafer on the optical axis AX (Z-axis) direction and a rotation direction around the Z-axis.
10 are fixed.

12 is a case where the θ-Z stage is mounted and the optical axis AX (Z
(XY axis) that is movable in the XY directions orthogonal to the axis.

Next, an element electron optical system array will be described with reference to FIG.
3 will be described.

The element electron optical system array 3 includes a plurality of element electron optical systems as a group (subarray), and a plurality of subarrays are formed. In this embodiment, five sub-arrays A to E are formed. In each subarray, a plurality of element electron optical systems are two-dimensionally arranged. In each subarray of this embodiment, 27 element electron optical systems such as C (1,1) to C (3,9) are used. Are formed.

FIG. 3 is a sectional view of each element electron optical system.

In FIG. 3, AP-P is an illumination electron optical system 2
This is a substrate having an aperture (AP1) that defines the shape of an electron beam that is illuminated and transmitted by the electron beams that are substantially parallel to each other, and is a substrate common to other element electron optical systems. That is, the substrate AP-P is a substrate having a plurality of openings.

Reference numeral 301 denotes a blanking electrode having a pair of electrodes and having a deflection function, and reference numeral 302 denotes a substrate having an opening (AP2) larger than the opening (AP1), which is common to other element electron optical systems. A blanking electrode 3 is placed on the substrate 302.
A wiring (W) for turning on / of the electrode with 01 is formed. That is, the substrate 302 is a substrate having a plurality of openings and a plurality of blanking electrodes.

Numeral 303 denotes three opening electrodes, the upper and lower electrodes are set to the same accelerating potential V0, and the intermediate electrode is set to a different potential.
This is an electron optical system using two unipotential lenses 303a and 303b having a converging function maintained at V1 or V2. Each of the aperture electrodes is laminated on a substrate with an insulator interposed therebetween, and the substrate is a substrate common to other element electron optical systems. That is, the substrate is a substrate having a plurality of electron optical systems 303.

The shape of the upper, middle, and lower electrodes of the unipotential lens 303a and the shape of the upper and lower electrodes of the unipotential lens 303b are as shown in FIG. The electrodes are set to a common potential in all element electron optical systems by a first focus / astigmatism control circuit described later.

Since the potential of the intermediate electrode of the unipotential lens 303a can be set for each element electron optical system by the first focus / astigmatism control circuit, the focal length of the unipotential lens 303a can be set for each element electron optical system.

The intermediate electrode of the unipotential lens 303b is composed of four electrodes as shown in FIG.
Since the potential of each electrode can be set individually by the focus / astigmatism control circuit and can be set individually for each element electron optical system, the unipotential lens 303b can have a different focal length in a cross section orthogonal to the element electron optics. It can be set individually for each system.

As a result, by controlling the intermediate electrodes of the electron optical system 303, the electron optical characteristics (intermediate image forming position, astigmatism) of the element electron optical system can be controlled. Here, when controlling the intermediate image forming position, the size of the intermediate image is determined by the ratio between the focal length of the illumination electron optical system 2 and the focal length of the electron optical system 303 as described above. The intermediate image system formation position is moved by moving the principal point position while keeping the focal length of the intermediate image system constant. Thereby, the sizes of the intermediate images formed by all the element electron optical systems can be substantially the same, and the positions in the optical axis direction can be different.

The electron beam made substantially parallel by the illumination electron optical system 2 forms an intermediate image of the electron source through the aperture (AP1) and the electron optical system 303. Here, a corresponding aperture (AP1) is located at or near the front focal position of the electron optical system 303,
The corresponding blanking electrode 301 is located at or near the intermediate image forming position of the electron optical system 303 (the rear focal position of the electron optical system 303). As a result, the beam is not deflected like the electron beam bundle 305 unless an electric field is applied between the blanking electrodes 301. On the other hand, when an electric field is applied between the blanking electrodes 301, the beam is deflected like an electron beam bundle 306. Then, since the electron beam 305 and the electron beam 306 have different angular distributions on the object plane of the reduction electron optical system 4, the electron beam 305 at the pupil position of the reduction electron optical system 4 (on the P plane in FIG. 1). And the electron beam bundle 306 are incident on mutually different regions. Accordingly, the blanking aperture BA that transmits only the electron beam bundle 305 is set at the pupil position (P in FIG. 1) of the reduced electron optical system.
On the surface).

The electron lens of each element electron optics corrects the field curvature and astigmatism generated when the intermediate image formed by each is reduced and projected on the surface to be exposed by the reduction electron optical system 4. Then, the electric potentials of the two intermediate electrodes of each electron optical system 303 are individually set to make the electron optical characteristics (intermediate image formation position, astigmatism) of each element electron optical system different. However, in this embodiment, in order to reduce the wiring between the intermediate electrode and the first focus / astigmatism control circuit, the element electron optical systems in the same sub-array have the same electro-optical characteristics. The characteristics (intermediate image formation position, astigmatism) are controlled for each sub-array.

Further, a plurality of intermediate images are formed by the reduction electron optical system 4.
In order to correct the distortion that occurs when the image is reduced and projected on the surface to be exposed, the distortion characteristics of the reduction electron optical system 4 are known in advance, and based on that, the direction orthogonal to the optical axis of the reduction electron optical system 4 The position of each element electron optical system is set.

Next, FIG. 5 shows a system configuration diagram of this embodiment.

The focal length control circuit FC includes an illumination electron optical system 2
By adjusting the electron optical power (focal length) of at least two electron lenses of the electronic lenses 2a, 2b, and 2c, the illumination electron optical system can be maintained while maintaining the focal position on the electron source side of the illumination electron optical system 2. 2 is a circuit for controlling the focal length.

The blanking control circuit 14 turns on / of the blanking electrode of each element electron optical system of the element electron optical array 3.
Control circuit for individually controlling f, first focus / astigmatism control circuit 15
Is a control circuit for individually controlling the electron optical characteristics (intermediate image formation position, astigmatism) of each element electron optical system of the element electron optical array 3.

The second focus / astigmatism control circuit 16 includes a dynamic stig coil 8 and a dynamic focus coil 7.
The deflection control circuit 17 controls the deflector 6 and the magnification adjustment circuit 18 controls the focal position and astigmatism of the reduction electron optical system 4. The refocus control circuit 19 is a control circuit that controls the current flowing through the refocus coil 9 to adjust the focal position of the reduction electron optical system 4.

The stage drive control circuit 20 is a control circuit that controls the drive of the XY stage 12 in cooperation with the laser interferometer 21 that detects the position of the XY stage 12 by controlling the drive of the θ-Z stage.

The control system 22 controls the plurality of control circuits and the backscattered electron detector 9 / Faraday cup 10 in synchronization with each other for exposure and alignment based on the exposure control data from the memory 23. The control system 22 is controlled by a CPU 25 that controls the entire electron beam exposure apparatus via an interface 24.

(Explanation of Exposure Operation) The exposure operation of the electron beam exposure apparatus of this embodiment will be described with reference to FIG.

The control system 22 commands the deflection control circuit 17 based on the exposure control data from the memory 23 to deflect a plurality of electron beams from the elementary electron optical system array by the sub deflector 62 of the deflector 6. , Blanking control circuit 14
The blanking electrode of each element electron optical system to the wafer 5
Is turned on / off according to the pattern to be exposed. At this time X
The Y stage 12 is continuously moving in the X direction. The electron beam from the element electron optical system is applied to the wafer 5 as shown in FIG.
The upper element exposure area (EF) is scanned and exposed starting from a black square. Also, as shown in FIG. 6B, the element exposure areas (EF) of the plurality of element electron optical systems in the sub-array are set to be two-dimensionally adjacent.
Above, a sub-array exposure field (SEF) composed of a plurality of element exposure areas (EF) is exposed. at the same time,
On the wafer 5, a sub-array A as shown in FIG.
Sub-array exposure field formed by each of E to E
A subfield composed of (SEF) is exposed. In other words, a subfield composed of a plurality of element exposure areas (EF) arranged two-dimensionally adjacent to each other is exposed.

The control system 22 instructs the deflection control circuit 17 to expose the subfield 2 after exposing the subfield 1 shown in FIG. A plurality of electron beams from the optical system array are deflected. Then, as described above, the deflection control circuit 17 is again commanded to deflect the plurality of electron beams from the element electron optical system array by the sub deflector 62 of the deflector 6, and to the blanking control circuit 14, The blanking electrode of the electron optical system is turned on / off according to the pattern to be exposed on the wafer 5.
off to expose subfield 2. And FIG.
As shown in (B), subfields such as subfields 3 and 4 are sequentially exposed to expose a pattern on the wafer 5. That is, as shown in FIG. 8, assuming that PA is a pattern area on the wafer 5 on which a pattern based on pattern data is drawn, the electron beam exposure apparatus of this embodiment sequentially sets the pattern area PA in units of subfields. Expose.

When exposing a sub-field, at a deflection position where all of a plurality of electron beams are blocked, a control method for deflecting and exposing the electron beam without stabilization (a vector scan control method in a multi-electron beam; Or a conventional control method in which a plurality of electron beams are deflected with a constant deflection width (minimum deflection width), and are sequentially settled and exposed (raster scan control method in a multi-electron beam; hereinafter, raster scan control method). Exposure is performed by selecting either one of the control methods. This is because the deflection cycle of the sub deflector 62 when exposing the subfield is constant, the settling time (so-called exposure time) Ts (sec) at the deflection position of each electron beam, and the electron beam is deflected from a certain deflection position. Assuming that the maximum settling wait time in the subfield among the settling wait times until settling to the desired deflection position is To (sec), the deflection cycle Td (sec) of the sub deflector 62 is Td = Ts + To. . Also, since the settling wait time becomes longer as the deflection width is wider, the vector scan control method may have a wider deflection width from the settling position to the settling position than the raster scan control method. In this case, the settling wait time is longer than in the raster scan control method. As a result, the deflection cycle of the vector scan control method is longer than that of the raster scan control method. Conversely, the number of positions for deflecting and setting within the subfield is smaller in the vector scan control system than in the raster scan control system. Then, the optimal control method for exposing the subfield in a short time depends on the deflection period and the number of positions to be settled. Further, the deflection cycle and the number of positions to be settled differ depending on the drawing pattern. Therefore, in the present invention, the control method is selected based on the drawing pattern (pattern data), and the sub-field is exposed by the selected control method.

(Explanation of Exposure Control Data Creation Processing) A method of creating exposure control data of the electron beam exposure apparatus of this embodiment will be described.

When the pattern data of the pattern to be exposed on the wafer is input, the CPU 25 executes a process of creating exposure control data as shown in FIG.

Each step will be described. (Step S101) Pattern feature information (minimum line width, line width type, shape) is detected from the pattern data. In this embodiment, the minimum line width is detected. (Step S102) Based on the detected pattern information, the minimum deflection width given to the electron beam by the sub deflector 62 and the electron beam diameter (the size of the electron source image formed on the wafer) are determined. In this embodiment, an integral multiple of the minimum deflection width is
The arrangement pitch of the plurality of electron beams (on the wafer).
The minimum deflection width is determined to be approximately one quarter of the minimum line width. Also,
The electron beam diameter is determined so as to be substantially equal to a square circumscribed circle having the minimum deflection width as a side. (Step S103) The input pattern data is divided into data in units of subfields determined by the electron beam exposure apparatus of the present embodiment. (Step S104) One subfield is selected. (Step S105) The deflection position (reference position) determined by the main deflector 61 when exposing the selected subfield is determined. (Step S106) The pattern data of the selected sub-field is divided into pattern data for each element exposure region of each element electron optical system, and the determined minimum deflection width of the sub deflector 62 is set as an array interval and the array element FME is used. A common array to be configured is set, and pattern data is converted into data expressed on the common array for each of the element electron optical systems. Hereinafter, in order to simplify the description, a description will be given of a process regarding pattern data when performing exposure using the two elementary electron optical systems a and b.

FIGS. 10A and 10B show patterns P to be exposed by the elementary electron optical systems a and b adjacent to the deflecting array DM.
a and Pb are shown. In other words, each element electron optical system is a hatched arrangement position where the pattern exists,
The blanking electrode is turned off, and the electron beam is irradiated on the wafer. The data of the array position to be exposed for each elementary electron optical system as shown in FIGS.
As shown in FIG. 10 (C), a first region FF (black portion) composed of an arrangement position when at least one of the elementary electron optical systems a and b is exposed, and the elementary electron optical systems a and b b. A second area NN (open area) consisting of an array position when both are not exposed in common is determined. When a plurality of electron beams are located in the first area FF on the array, the electron beam is deflected by the deflector 6 and exposed by using the minimum deflection width (array interval of the array) as a unit. All patterns to be exposed can be exposed. When a plurality of electron beams are located in the second area NN on the array, the electron beam is deflected without being settled, so that unnecessary deflection of the electron beam can be reduced and exposure can be performed, and unnecessary control data can be obtained. Can be omitted. In other words, after exposing the first area (FF),
By skipping over the area (NN) and exposing to the next first area (FF), exposure can be performed in a shorter time by reducing the deflection having a settling time. Then, the CPU 25 determines the array position of the array element to be exposed from the data on the areas FF and NN shown in FIG. 10C, and further sets the electron beam from the data shown in FIGS. 10A and 10B. The on / off of the blanking electrode for each element electron optical system corresponding to the array position to be performed is determined. That is, data for a so-called vector scan control system is created. Here, since the minimum deflection width and the order of deflection in the array have already been determined, the array element number is determined for each array element. Therefore, the array number is determined as the array position. (Step S107) From the data obtained in step S106, the number of set positions when the subfield is exposed by the vector scan control method and the maximum deflection width from the set position of the sub deflector to the next set position are detected. (Step S108) When the subfield is exposed by the vector scan control method based on the maximum deflection width detected by the vector scan control method, based on the relationship between the maximum deflection width and the settling waiting time obtained in advance by an experiment or the like. Is settled waiting time To (V), and based on the maximum deflection width (same value as the minimum deflection width) in the raster scan control method, the settling wait time To (R) when the subfield is exposed by the raster scan control method Ask for. Then, from the settling time Ts at the time of exposure, the deflection cycle of each method is obtained as follows. Deflection cycle Td (V) = To (V) in vector scan control
+ Ts Deflection cycle in raster scan control method Td (R) = To (R)
+ Ts In addition, set the number of set positions in the vector scan control method to N
(V), the number of settling positions in the raster scan control method is N
From (R), the subfield exposure time of each system is calculated as follows. Exposure time Tsub (V) = Td in vector scan control method
(V) * N (V) Exposure time Tsub (R) = Td in raster scan control method
(R) * N (R) (Step S109) The exposure time of each control method is compared, and the shorter one is determined as the control method for exposing the subfield. (Step S110) It is determined whether or not the processing of steps S104 to S109 has been completed for all subfields. If there is an unprocessed subfield, the process returns to step S104 to select an unprocessed subfield. (Step S111) When the processes of steps S104 to S109 are completed for all the subfields, the exposure control data of the minimum deflection width and the electron beam diameter of the sub deflector 61 as shown in FIG. The reference position to be determined, the control method, the deflection period of the sub deflector 62 corresponding to the control method, the array position determined by the sub deflector 62, and the opening and closing of the electron beam irradiation of each element electron optical system at each array position The exposure control data for each field is stored. However, when the control method is the vector scan control method, the data of the array position where all of the plurality of electron beams are blocked is deleted. When the control method is the raster-scan control method, data at all arrangement positions in the subfield determined by the minimum deflection width of the sub deflector 62 is stored.

In this embodiment, these processes are performed by the CPU 25 of the electron beam exposure apparatus. However, the purpose and effect are not changed even if the processing is performed by another processing apparatus and the exposure control data is transferred to the CPU 25.

(Explanation of Exposure Based on Exposure Control Data) CP
When U25 instructs the control system 22 to execute "exposure" via the interface 24, the control system 22 transmits the transferred memory 23
The steps as shown in FIG. 12 are executed based on the above exposure control data.

Each step will be described. (Step S201) Instruct the focal length control circuit FC to change the focal length of the illumination electron optical system 2 to set the determined electron beam diameter. (Step S202) Command the deflection control circuit 17 to set the minimum deflection width of the sub deflector 61 to the determined minimum deflection width. (Step S203) The deflection control circuit 17 is instructed so that the plurality of electron beams from the elementary electron optical system array are located at the reference position, which is the starting point when exposing the subfield, and the subfield to be exposed by the main deflector 61 To deflect the plurality of electron beams. Further, it instructs the second focus / astigmatism control circuit 17 in accordance with the deflection position determined by the main deflector 61, and corrects the focus position of the reduction electron optical system 4 based on the dynamic focus correction data obtained in advance. Like dynamic focus coil
7, and controls the dynamic stig coil 8 so as to correct the astigmatism of the reduction electron optical system based on the dynamic astigmatism correction data obtained in advance. (Step S204) Instruct the deflection control circuit 17 to switch the deflection cycle of the sub deflector 62 to a deflection cycle corresponding to the control method of the subfield to be exposed. Further, a periodic signal determined by the deflection cycle is generated. Then, in synchronism with the periodic signal, the plurality of electron beams from the elementary electron optical system array are deflected by the sub deflector 62 to the deflection position determined by the exposure control data in units of the switched minimum deflection width. At the same time, in synchronization with the periodic signal, the blanking control circuit 14 is commanded to turn on / off the blanking electrodes of the respective element electron optical systems according to the pattern to be exposed on the wafer 5. However, when the vector scan control method is selected as the control method, the control is performed so that the electron beam is deflected without being settled at the deflection position where all of the plurality of electron beams are cut off. In other words, from the first deflection position where at least one of the plurality of electron beams is irradiated, a second deflection position where all of the plurality of electron beams are cut off, and at least one of the next plurality of electron beams is irradiated. Is controlled to be deflected to the first deflection position. When the raster scan control method is selected as the control method, control is performed so that the light beam is deflected with a constant deflection width (minimum deflection width) and is settled sequentially. Further, in order to correct the blur of the electron beam due to the Coulomb effect, the refocusing circuit is instructed, and the refocusing coil 9 controls the reduction electron optics based on the number of electron beams irradiated to the wafer without being interrupted by the blanking electrode. Adjust the focal position of system 4. At this time, XY stage 1
2 continuously moves in the X direction, and the deflection control circuit 17
The deflection position of the electron beam is controlled, including the amount of movement of the Y stage 12. As described above, as a result, as shown in FIG. 6A, the element exposure area (EF) on the wafer 5 is scanned and exposed starting from a black square. Also, as shown in FIG. 6B, the element exposure areas (EF) of the plurality of element electron optical systems in the sub-array are set to be adjacent to each other. The sub-array exposure field (SEF) composed of the exposure area (EF) is exposed. At the same time, on the wafer 5, a subfield composed of a subarray exposure field (SEF) formed by each of the subarrays A to E as shown in FIG. (Step S205) If there is a subfield to be exposed next, the process returns to step S203; otherwise, the exposure ends.

(Second Embodiment) In the first embodiment, the exposure time of each system is calculated and the shorter one is selected. However, the number of settling positions in the vector scan control system is simply reduced. For example, when the value is equal to or more than a predetermined value such as 50% of the number of set positions in the raster scan control method, the raster scan control method may be selected.

(Explanation of Device Production Method of the Present Invention) An embodiment of a device production method using the above-described electron beam exposure apparatus will be described.

FIG. 13 shows a micro device (a semiconductor chip such as an IC or an LSI, a liquid crystal panel, a CCD, a thin film magnetic head,
2 shows a flow of manufacturing a micromachine or the like. Step 1
In (circuit design), a circuit of a semiconductor device is designed.
In step 2 (exposure control data creation), exposure control data of the exposure apparatus is created based on the designed circuit pattern. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the wafer and the exposure apparatus to which the prepared exposure control data has been input. The next step 5 (assembly) is called a post-process, and step 4
Is a process of forming a semiconductor chip using the wafer produced by the above process, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 14 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 1
In 5 (resist processing), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern is printed on the wafer by exposure using the above-described exposure apparatus. Step 17
In (development), the exposed wafer is developed. Step 18
In (etching), portions other than the developed resist image are scraped off. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device which has been conventionally difficult to manufacture at low cost.

[0066]

As described above, according to the present invention, a multi-electron beam type exposure method and apparatus capable of achieving a larger throughput for selecting an optimal control method for each subfield based on pattern data. Can be provided.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a main part of an electron beam exposure apparatus according to the present invention.

FIG. 2 is a diagram illustrating an element electron optical system array 3.

FIG. 3 is a diagram illustrating an element electron optical system.

FIG. 4 is a diagram illustrating electrodes of the elementary electron optical system.

FIG. 5 is a diagram illustrating a system configuration according to the present invention.

FIG. 6 is a view for explaining an exposure field (EF) and a sub-array exposure field (SEF).

FIG. 7 is a diagram illustrating a subfield.

FIG. 8 is a view for explaining the relationship between a subfield and a pattern area.

FIG. 9 is a view for explaining exposure control data creation processing.

FIG. 10 explains a pattern to be exposed by each elementary electron optical system and determination of an area of an array determined by a deflector.

FIG. 11 is a view for explaining exposure control data.

FIG. 12 is a view for explaining exposure based on exposure control data.

FIG. 13 is a diagram illustrating a flow of manufacturing a micro device.

FIG. 14 is a diagram illustrating a wafer process.

FIG. 15 is a diagram illustrating a conventional multi-electron beam type exposure apparatus.

[Explanation of symbols]

 Reference Signs List 1 electron gun 2 illumination electron optical system 3 element electron optical system array 4 reduction electron optical system 5 wafer 6 deflector 7 dynamic focus coil 8 dynamic stig coil 9 refocus coil 10 Faraday cup 11 θ-Z stage 12 XY stage 13 intensity distribution Control circuit 14 Blanking control circuit 15 First focus / astigmatism control circuit 16 Second focus / astigmatism control circuit 17 Deflection control circuit 18 Magnification adjustment circuit 19 Refocus control circuit 20 Stage drive control circuit 21 Laser interferometer 22 Control system Reference Signs List 23 memory 24 interface 25 CPU AP-P substrate with opening FC focal length control circuit

Claims (10)

[Claims] 1. A method according to claim 1, wherein a plurality of electron beams are deflected on a surface to be exposed, the irradiation of each electron beam is individually controlled for each deflection, and a pattern is drawn in an element exposure area for each electron beam. An electron beam exposure method for sequentially drawing a pattern in a subfield composed of element exposure regions, wherein pattern data of a pattern to be drawn on the surface to be exposed is divided in units of the subfield, and the subfield is exposed. As a control method at the time of performing, the first control method of deflecting and stabilizing and exposing the plurality of electron beams with a constant deflection width, or at a deflection position where all of the plurality of electron beams are cut off, Either one of the second control systems for deflecting and exposing an electron beam without setting is selected based on pattern data for each subfield. And floor, when exposing each subfield, an electron beam exposure method characterized by having the steps of exposing a selected control scheme. 2. The electron beam exposure method according to claim 1, wherein the selecting step includes a step of calculating and comparing a time for exposing a subfield by the first and second control methods. 3. The method according to claim 2, wherein the selecting step includes a step of selecting the first control method when the number of set positions in the case of performing exposure by the second control method is equal to or more than a predetermined value. The electron beam exposure method according to claim 1. 4. A device manufacturing method, wherein a device is manufactured using the electron beam exposure method according to claim 1. 5. An electron beam exposure apparatus for drawing a pattern on a surface to be exposed by using a plurality of electron beams, comprising: a deflecting means for deflecting the plurality of electron beams on the surface to be exposed; Irradiation control means for individually controlling the irradiation of the electron beam, and deflecting the plurality of electron beams by the deflecting means to draw a pattern in an element exposure area for each electron beam,
A pattern is sequentially drawn on a subfield composed of the plurality of element exposure areas, and as a control method when exposing the subfield, the plurality of electron beams are deflected with a constant deflection width and settled by the deflecting unit. In the first control method for exposing, or in the deflection position where all of the plurality of electron beams are blocked by the irradiation control means, the second control for deflecting and exposing the electron beam without setting by the deflecting means. Control means for selecting one of the methods to perform exposure. 6. The electron beam according to claim 5, wherein said control means selects a control method based on control data having information on a control method determined based on a pattern exposed in a subfield. Exposure equipment. 7. The predetermined control method includes the first,
7. The electron beam exposure apparatus according to claim 6, wherein the time is determined based on a result of calculating and comparing the time for exposing the subfield by the second control method. 8. The electron beam according to claim 6, wherein the first control method is selected when the number of set positions in exposure in the second control method is equal to or greater than a predetermined value. Exposure equipment. 9. The deflecting unit has an electrostatic deflector and an electromagnetic deflector, and the control unit is configured to deflect the plurality of electron beams in the element exposure area by using the electrostatic deflector. 9. An electron beam exposure apparatus according to claim 5, wherein said electromagnetic deflector is used when deflecting said plurality of electron beams from one subfield to the next subfield using a deflector. 10. A device manufacturing method, wherein a device is manufactured using the electron beam exposure apparatus according to claim 5.