JPH1126348A - Method and apparatus for electron beam exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for multiple electron beam exposure wherein a larger throughput is attained. SOLUTION: A multiple electron beam exposure method with a continuous stage movement comprises a first decision stage, where it is decided that at least one sub field of at least one main field is exposed to a plurality of electron beams, after settlement at such a polarization position that at least one of plurality of electron beams is radiated, while the plurality of electron beams is polarized for exposure without settlement at such polarization position as the entire electron beam is cut off, a stage where exposure time for each main field is calculated, and a second decision stage wherein the moving speed of a stage is decided to be such speed at which a main field corresponding to within such exposure time as that calculated for each main field can be exposed.

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. 16 schematically shows a multi-electron beam type exposure apparatus. 501a, 501b, 501c individually turn on the electron beam
An electron gun that can be turned off. 502 is an electron gun 501a, 501b, 501
A reduction electron optical system for reducing and projecting a plurality of electron beams from c onto the wafer 503, and a deflector 504 for deflecting the plurality of electron beams reduced and projected on 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. 16A, 16B and 16C show electron guns 501a and 501a, respectively.
The figure shows that electron beams from 501b and 501c expose 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 solving the above-mentioned problems, in which a plurality of electron beams are exposed while continuously moving a stage on which an object to be exposed is mounted. By deflecting the surface, individually controlling the irradiation of each electron beam for each deflection, and drawing a pattern in the element exposure area for each electron beam, the subfield composed of the plurality of element exposure areas is drawn. By sequentially drawing a plurality of subfields arranged in a direction orthogonal to the continuous movement direction, a main field composed of the plurality of subfields is drawn, and furthermore, a plurality of main fields arranged in the continuous movement direction are sequentially drawn The at least one sub-field of at least one main field comprises at least one of the plurality of electron beams. In the deflection position where one is irradiated, the plurality of electron beams are settled and exposed, and in the deflection position where all of the plurality of electron beams are blocked, the plurality of electron beams are deflected without setting and exposed. Determining a first determining step, calculating an exposure time for each main field, and determining a moving speed of the stage to a moving speed at which the main field corresponding to the exposure time calculated for each main field can be exposed. And a second determining step.

[0010] The first determining step is determined based on a pattern to be drawn in each subfield.

The calculating step may include calculating the exposure time based on the number of settling of the plurality of electron beams, the settling time, and the settling wait time in the main field.

[0012] The second determining step includes a step of determining a moving speed of the stage for each main field.

In the second determining step, the moving speed of the main field having a high moving speed is determined so that the difference between the determined moving speeds of the main fields adjacent in the continuous moving direction is equal to or less than a predetermined value. And determining a lower speed than the determined moving speed.

By sequentially drawing a plurality of main fields arranged in the continuous movement direction, a frame composed of the plurality of main fields is drawn, and a plurality of frames arranged in a direction perpendicular to the continuous movement direction are sequentially drawn. A step of determining the moving speed of the stage on a frame-by-frame basis.

One embodiment of the electron beam exposure apparatus according to the present invention is an electron beam exposure apparatus that draws a pattern on an object to be exposed by using a plurality of electron beams. Deflecting means for deflecting the plurality of electron beams on the surface to be exposed; irradiation control means for individually controlling irradiation of each electron beam for each deflection; and a plurality of deflecting means for continuously moving the stage. The electron beam is deflected on the surface to be exposed, the irradiation control means individually controls the irradiation of each electron beam for each deflection, and draws a pattern in an element exposure area for each electron beam to thereby form the plurality of elements. A subfield composed of an exposure region is drawn, and a plurality of electron beams are deflected by the deflecting means, and a plurality of subfields arranged in a direction orthogonal to the continuous movement direction are drawn. The main field composed of the plurality of sub-fields is drawn by sequentially drawing the fields, and the plurality of main fields arranged in the continuous movement direction by further deflecting a plurality of electron beams by the deflecting means are drawn at least. At least one subfield of one main field is set at a deflection position where at least one of the plurality of electron beams is irradiated, the plurality of electron beams are settled by the deflecting means, and all of the plurality of electron beams are blocked. At the deflection position, the plurality of electron beams are deflected without settling by the deflecting means, and the moving speed of the stage is adjusted based on the exposure time of each main field within the exposure time of the main field. Control means for controlling the moving speed at which exposure is possible, That.

The control means switches the moving speed of the stage when the main field to be drawn changes.

The control means controls the moving speed of the stage such that the difference in the moving speed becomes less than a predetermined value when the moving speed of the stage is switched.

The control means draws a frame composed of the plurality of main fields by deflecting a plurality of electron beams by the deflecting means and sequentially drawing a plurality of main fields arranged in a continuous moving direction. A plurality of frames arranged in a direction orthogonal to a continuous movement direction are sequentially drawn by stepping the object to be exposed by the stage, and the moving speed of the stage is switched when a frame to be drawn changes.

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.

[0021]

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 the 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 focal length is represented by the following equation.

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. AX on optical axis
Is located 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 -f
Reduced to 2 / 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 drawing deflector that deflects a plurality of electron beams from the elementary electron optical system array 3 and deflects a plurality of electron source images on the wafer 5 by substantially the same deflection width in the X and Y directions. is there. The drawing 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. 61 is an electromagnetic deflector, and the sub deflector 62 is an electrostatic deflector.

SDEF is a stage follow deflector for making a plurality of electron beams from the elementary electron optical system array 3 follow the continuous movement of the XY stage 12. The stage following deflector SDEF is an electrostatic deflector.

Numeral 7 denotes a dynamic focus coil for correcting a shift of the focus position of the electron source image due to deflection aberration generated when the drawing deflector 6 is operated. This is a dynamic stig coil for correcting astigmatism of the generated deflection aberration.

Numeral 9 denotes a refocus 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.

Numeral 11 denotes a θ-Z stage on which a wafer is placed and which is movable in the direction of the optical axis AX (Z axis) and in the direction of rotation around the Z axis. The stage reference plate 13 and the Faraday cup
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, the elementary electron optical system array 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. For example, as shown in FIG.
Five sub-arrays A to E are formed, and in each sub-array, a plurality of element electron optical systems are two-dimensionally arranged. In each sub-array of the present embodiment, C (1,1) to C (3, As shown in 9), 27 element electron optical systems are formed.

FIG. 3 is a cross-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.

Numeral 301 denotes a blanking electrode having a pair of electrodes and having a deflecting function. Numeral 302 denotes a substrate having an opening (AP2) which is common to other element electron optical systems. A wiring (W) for turning on / of the electrode with the blanking electrode 301 is formed on the substrate 302. That is, the substrate 302 is a substrate having a plurality of openings and a plurality of blanking electrodes.

Reference 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 formation 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 lenses of the respective element electron optics are used to correct 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.
Is a control circuit for controlling the focal position and astigmatism of the reduction electron optical system 4 by controlling the drawing deflection control circuit 17.
Control circuit, stage follow-up control circuit SDC is XY
A control circuit for controlling the stage following deflector SDEF so that the electron beam follows the continuous movement of the stage 12, a magnification control circuit 18, a control circuit for adjusting the magnification 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 θ-Z stage and controls the drive of the XY stage 12 in cooperation with the laser interferometer 21 that detects the position of the XY stage 12.

The control system 22 controls the plurality of control circuits, the backscattered electron detector 9 and the 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.

(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 drawing deflection control circuit 17 based on the exposure control data from the memory 23,
The six sub-deflectors 62 deflect a plurality of electron beams from the element electron optical system array, and instruct the blanking control circuit 14 to expose the blanking electrodes of each element electron optical system to the wafer 5 in accordance with the pattern to be exposed. on / off.
At this time, the XY stage 12 is continuously moving in the X direction.
The stage following control circuit is instructed so that a plurality of electron beams follow the movement of the Y stage.
EF deflects multiple electron beams. Then, the electron beam from the element electron optical system is transferred to the wafer as shown in FIG.
The element exposure area (EF) on 5 is scanned and exposed. In this embodiment, Sx = Sy = 4 μm. Since the element exposure areas (EF) of the plurality of element electron optical systems of the element electron optical system array are set to be two-dimensionally adjacent to each other,
On 5, a subfield (SF) composed of a plurality of element exposure areas (EF) that are arranged two-dimensionally adjacent and are exposed simultaneously is exposed. In this embodiment, the plurality of element exposure areas (EF) are M = 64 (pieces) in the X direction and N = 64 in the Y direction.
64 (number) are arranged, and the size of the subfield (SF) is 256 × 256 (μm ² ).

The control system 22 controls the subfield 1 shown in FIG.
After exposing (SF1), the deflection control circuit 17 is commanded to expose the subfield 2 (SF2), and the main deflector 61 of the drawing deflector 6 is exposed.
Thereby, a plurality of electron beams from the elementary electron optical system array are deflected in a direction orthogonal to the stage scanning direction. Then, as described above, the drawing deflector control circuit 17 is again commanded to deflect a plurality of electron beams from the elementary electron optical system array by the sub deflector 62 of the drawing deflector 6,
Command the blanking control circuit 14 to expose the blanking electrode of each element electron optical system to the wafer 5 according to the pattern to be exposed.
n / off to expose subfield 2 (SF2). Then, as shown in FIG. 6, the subfields (SF1 to SF16)
Are sequentially exposed to expose a pattern on the wafer 5. As a result, a main field (MF) composed of subfields (SF1 to SF16) arranged in a direction orthogonal to the stage scanning direction on the wafer 5 is exposed. Here, the subfields are arranged in L = 16 (pieces) in the Y direction, and the size of the main field (MF) is 256 × 4096 (μm ² ).

After exposing the main field 1 (MF1) shown in FIG. 6, the control system 22 instructs the drawing deflection control circuit 17 to sequentially arrange the main fields (MF2, MF2,
A plurality of electron beams from the elementary electron optical system array are deflected to MF3, MF4,.

That is, the electron beam exposure apparatus of this embodiment continuously moves the stage on which the wafer is mounted,
A plurality of electron beams are deflected on the wafer, the irradiation of each electron beam is individually controlled for each deflection, and a pattern is drawn in an element exposure region for each electron beam. Draw a subfield, draw a main field composed of the plurality of subfields by sequentially drawing a plurality of subfields arranged in a direction orthogonal to the continuous movement direction, and further draw a plurality of Draw the main field sequentially.

Here, when exposing a subfield, 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 stabilizing it (a vector scan control method for a multi-electron beam) , Hereinafter referred to as a vector scan control method) or a conventional multiple electron beam with a constant deflection width (minimum deflection width).
Exposure is performed by selecting one of the control methods (raster scan control method for a multi-electron beam, hereinafter referred to as a raster scan control method) for deflecting and sequentially setting and exposing. This is because the deflection cycle of the sub deflector 62 when exposing the subfield is constant, and the settling time (so-called exposure time) Ts (se
c), among the settling wait times until the electron beam is deflected from a certain deflection position and settles to a desired deflection position, the maximum settling wait time in the subfield is defined as To (sec). The deflection cycle Td (sec) 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 characteristic 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 characteristic information, the minimum deflection width and electron beam diameter given to the electron beam by the sub deflector 62 (the size of the electron source image formed on the wafer)
To determine. In this embodiment, an integral multiple of the minimum deflection width is the arrangement pitch (on the wafer) of the plurality of electron beams. The minimum deflection width is determined to be approximately one quarter of the minimum line width. In addition, the electron beam diameter is determined to be substantially equal to a circumscribed circle of a square having the minimum deflection width as a side.

(Step S103) The input pattern data is divided into data in units of main fields determined by the electron beam exposure apparatus of this embodiment.

(Step S104) At the time of exposure, a main field to be exposed first is selected.

(Step S105) The pattern data of the selected main field is divided into data in units of subfields determined by the electron beam exposure apparatus of this embodiment.

(Step S106) One subfield is selected.

(Step S107) The deflection position (reference position) determined by the main deflector 61 when exposing the selected subfield is determined.

(Step S108) The pattern data of the selected subfield is divided into pattern data for each element exposure area of each elementary electron optical system, and the determined minimum deflection width of the sub deflector 62 is set as an array interval. A common array composed of the elements FME is set, and the pattern data is converted into data represented on the common array for each element electron optical system. Hereinafter, in order to simplify the description, two element electron optical systems a,
A process related to pattern data when performing exposure using b will be described. Arrays DM for deflection common to FIGS. 8A and 8B
Pattern P to be exposed by element electron optical systems a and b adjacent to
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. Therefore, the data of the array position to be exposed for each elementary electron optical system as shown in FIGS.
As shown in FIG. 8 (C), a first region FF (black portion) composed of an arrangement position when at least one of the element electron optical systems a and b is exposed, and the element 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. Multiple electron beams on the first array
In the area FF, all the patterns exposed on the wafer can be exposed by deflecting and exposing the electron beam by the drawing deflector 6 with the minimum deflection width (array interval) as a unit. . 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), it skips over the second area (NN) and moves to the next first area (F
By exposing by deviating to F), it is possible to reduce the deflection having a settling time and to perform exposure in a shorter time. And FIG.
From the data on the areas FF and NN shown in (C), the CPU 25 determines the array position of the array element to be exposed, and furthermore, FIG.
From the data shown in (B), the on / off state of the blanking electrode for each element electron optical system corresponding to the array position where the electron beam is settled
Determine / off. 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 S109) From the data obtained in step S108, the number of set positions (set times) when the subfield is exposed by the vector scan control method, and the number of set positions from the set position of the sub deflector to the next set position. Detect the maximum deflection width.

(Step S110) 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 wait time obtained in advance through experiments and the like. The settling wait time To (V) for the subfield is exposed based on the maximum deflection width (same value as the minimum deflection width) in the raster scan control method. Find (R). 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 S111) The exposure time of each control method is compared, and the shorter one is determined as the control method for exposing the subfield.

(Step S112) For all subfields of the selected main field, step S107
It is determined whether or not the processing from S111 to S111 has been completed. If there is an unprocessed subfield, the process returns to step S106 to select an unprocessed subfield. If not, step S113
Proceed to.

(Step S113) The exposure time of the selected main field is calculated by adding the exposure time of each subfield of the selected main field in the selected control method.

(Step S114) The moving speed of the stage when exposing each main field is determined based on the calculated exposure time for each main field. FIG. 9 (A)
Shows an example of the relationship between each main field (MF (N)) and the exposure time (T (n)). In this way, at least a part (subfield) of at least one main field is exposed by stabilizing the plurality of electron beams at a deflection position where at least one of the plurality of electron beams is irradiated,
When a plurality of electron beams are deflected for exposure without settling at a deflection position where all of the plurality of electron beams are blocked, the exposure time may differ between main fields. Therefore, in this embodiment, the stage moving speed (V (n)) that is inversely proportional to the exposure time is determined. For example, since the length of the main field (LMF) in the stage movement direction is 256 μm, if the exposure time T (n) = 2.56 ms, the stage movement speed
V (n) = 100 mm / s (= LMF / T (n)). FIG. 9B shows the relationship between each main field and the stage moving speed. Since the exposure is performed at the stage moving speed for each main field according to the exposure time of the main field, the wafer can be exposed in a shorter time. This is because, when the stage is controlled at a constant speed as in the conventional multi-electron beam type exposure apparatus, when exposing the next main field from the main field having a short exposure time, the next main field is controlled by the deflection range of the main deflector 61. This is because the exposure must be interrupted until it exists. However, the present invention does not require that downtime.

(Step S115) The stage moving speed of the selected main field, the reference position determined by the main deflector 61 for each subfield of the selected main field, the control method, and the deflection of the sub deflector 62 corresponding to the control method. The data on the period, 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 are 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 a subfield defined by the minimum deflection width of the sub deflector 62 is stored.

(Step S116) At the time of exposure, if there is a main field to be exposed next, the main field is selected and the process returns to step S105. At the time of exposure, if there is no main field to be exposed next, the process proceeds to step S117.

(Step S117) As shown in FIG. 10, the minimum deflection width of the sub deflector 61, the electron beam diameter, the stage moving speed for each main field, the reference position determined by the main deflector 61 for each subfield, Exposure control using, as elements, a control method, a deflection cycle of the sub deflector 62 corresponding to the control method, an arrangement position determined by the sub deflector 62, and data on opening and closing of electron beam irradiation of each element electron optical system at each arrangement position. Store the data.

In the present 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. 11 are executed based on the above exposure control data.

Each step will be described.

(Step S201) The focal length control circuit FC is instructed to change the focal length of the illumination electron optical system 2 to set the determined electron beam diameter.

(Step S202) The drawing deflection control circuit 17 is instructed to set the minimum deflection width of the sub deflector 61 to the determined minimum deflection width.

(Step S203) Stage drive control circuit 20
To switch the stage moving speed corresponding to the main field to be exposed, and control the XY stage 12.

(Step S204) The drawing deflection control circuit 17 is instructed so that a plurality of electron beams from the elementary electron optical system array are located at the reference positions when the first subfield of the main field to be exposed is exposed. A plurality of electron beams are deflected by a deflector 61 into a subfield to be exposed.

(Step S205) Command the drawing / 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. And
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 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 electrode of each element electron optical system according to the pattern to be exposed on the wafer 5.
off. 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, the XY stage 12 is continuously moving in the X direction, and
Reference numeral 17 controls the deflection position of the electron beam, including the amount of movement of the XY stage 12. As described above, as a result, the electron beam from the element electron optical system scans and exposes the element exposure area (EF) on the wafer 5 as shown in FIG. The element exposure areas (EF) of the plurality of element electron optical systems of the element electron optical system array are set to be two-dimensionally adjacent, and as a result, are arranged on the wafer 5 so as to be two-dimensionally adjacent. And a plurality of element exposure areas (E
The subfield (SF) composed of F) is exposed.
Next, the control system 22 executes the subfield 1 (SF1) shown in FIG.
After the exposure, the drawing deflection control circuit 17 is commanded to expose the subfield 2 (SF2), and the main deflector 61 of the drawing deflector 6 sends the light from the element electron optical system array in a direction orthogonal to the stage scanning direction. A plurality of electron beams are deflected. Then, as described above, the drawing deflector control circuit 17 is again commanded to deflect a plurality of electron beams from the elementary electron optical system array by the sub deflector 62 of the drawing deflector 6,
Command the blanking control circuit 14 to expose the blanking electrode of each element electron optical system to the wafer 5 according to the pattern to be exposed.
n / off to expose subfield 2 (SF2). Then, as shown in FIG. 6, the subfields (SF1 to SF16)
Are sequentially exposed to expose a pattern on the wafer 5. As a result, a main field (MF) composed of subfields (SF1 to SF16) arranged in a direction orthogonal to the stage scanning direction on the wafer 5 is exposed.

(Step S206) If there is a main field to be exposed next, the flow returns to step S203.
The exposure ends.

(Second Embodiment) In the first embodiment, the stage moving speed for each main field is determined so as to be inversely proportional to the exposure time for exposing the main field. However, if the difference in the determined moving speed between the main feels adjacent in the continuous moving direction is large, an excessive acceleration is applied to the stage, which makes it difficult to control the stage and degrades the position stability of the stage. I do. Therefore, in the present embodiment, the moving speed of the main field having a high moving speed is determined so that the difference in the determined moving speed between the main fields adjacent in the continuous moving direction is equal to or less than a predetermined value (Vp). Is determined to be lower than the moving speed.

The specific processing will be described with reference to FIG.

(Step S301) The relationship between each main field and the stage moving speed determined in the first embodiment (FIG. 9B) is input.

(Step S302) At the time of exposure, a main field to be exposed first is selected. Set the redetermination flag F to F =
Set to 0.

(Step S303) The difference between the stage moving speed of the selected main field and the stage moving speed of the main field exposed immediately before exposing the selected main field is calculated (there is no previous main field). If so, the process jumps to step S305.). If the difference is not smaller than or equal to a predetermined value that can ensure the controllability and stability of the stage, the process proceeds to step S304. If the value is equal to or less than the predetermined value (Vp), the process jumps to step S305.

(Step S304) The moving speed of the main field having the higher moving speed is determined again so that the difference in the moving speed becomes equal to or less than a predetermined value. Redetermination flag F
Is set to F = 1.

(Step S305) The difference between the stage moving speed of the selected main field and the stage moving speed of the main field exposed immediately after exposing the selected main field is calculated (when there is no immediately following main field). Jumps to step S305.). If the difference is not smaller than the predetermined value, the process proceeds to step S306. If the value is equal to or less than the predetermined value, the process jumps to step S307.

(Step S306) The moving speed of the main field having the higher moving speed is determined again so that the difference between the moving speeds becomes equal to or less than a predetermined value.

(Step S307) Immediately after exposing the selected main field, a main field to be exposed is selected, and the process returns to step S303. If there is no immediately following main field, the process proceeds to step S308.

(Step S308) The redetermined flag F is F = 1.
In the case of, the process returns to step S302. Redetermination flag F is F =
If it is 0, the process ends. The relationship between each main field and the stage moving speed determined in the first embodiment is
The result obtained by performing the above processing is shown in FIG.
Shown in

(Third Embodiment) In this embodiment, FIG.
As shown in FIG. 3, after exposing a frame (FL1) composed of a plurality of main fields in which exposure regions on the wafer 5 are arranged in the continuous movement direction, the stage 12 is stepped in the Y direction, and the stage 12 is moved in the continuous movement direction. And the next frame (FL2) is exposed. That is, frames arranged in a direction orthogonal to the continuous movement direction of the stage 12 are sequentially exposed.

In the first embodiment, the moving speed of the stage is determined for each main field. In the present embodiment, the moving speed of the stage is determined for each frame. Specifically, in the main field that makes up the frame,
The stage moving speed in the corresponding frame is determined based on the exposure time of the main field having the longest exposure time. Then, when the frame to be drawn is changed, the moving speed of the XY stage is switched to the determined moving speed, and the frame is drawn at the same stage moving speed.

(Description 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. 14 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. 15 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 was conventionally difficult to manufacture, at low cost.

[0105]

As described above, according to the present invention, since the stage speed is controlled according to the reduction of the exposure time of the main field, it is possible to provide a multi-electron beam type exposure method and apparatus capable of achieving a larger throughput. .

[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), a subfield (SF), and a main field (MF).

FIG. 7 is a view for explaining exposure control data creation processing.

FIG. 8 is a view for explaining a pattern to be exposed by each elementary electron optical system and determination of an area of an array determined by a drawing deflector.

FIG. 9 is a view for explaining a relationship between an exposure time and a stage moving speed for each main field and a relationship between a subfield and a pattern area.

FIG. 10 is a view for explaining exposure control data.

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

FIG. 12 is a view for explaining a method of determining a stage speed for each main field according to the second embodiment.

FIG. 13 illustrates a frame.

FIG. 14 is a diagram illustrating a flow of manufacturing a micro device.

FIG. 15 illustrates a wafer process.

FIG. 16 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 drawing deflector 7 dynamic focus coil 8 dynamic stig coil 9 refocus coil 10 Faraday cup 11 θ-Z stage 12 XY stage 13 stage Reference plate 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 23 Memory 24 Interface 25 CPU AP-P Substrate with Opening FC Focal Length Control Circuit SDEF Stage Tracking Deflector SDC Stage Tracking Control Circuit

Claims (13)

[Claims] 1. A method according to claim 1, wherein a plurality of electron beams are deflected on a surface to be exposed while continuously moving a stage on which the object to be exposed is mounted, and irradiation of each electron beam is individually controlled for each deflection. By drawing a pattern in the element exposure area, a subfield composed of the plurality of element exposure areas is drawn, and by sequentially drawing a plurality of subfields arranged in a direction orthogonal to the continuous movement direction, the plurality of subfields are drawn. An electron beam exposure method for drawing a main field composed of subfields and further drawing a plurality of main fields arranged in a continuous movement direction sequentially, wherein at least one subfield of at least one main field is formed by the plurality of electrons. At a deflection position where at least one of the beams is irradiated, the plurality of electron beams are settled and exposed, and the plurality of electron beams are exposed. A first determining step of deflecting and exposing the plurality of electron beams without setting at a deflection position at which all of the beams are blocked; and calculating an exposure time for each main field; A second determining step of determining the moving speed of the stage to a moving speed at which the main field corresponding to the exposure time calculated for each main field can be exposed. 2. The electron beam exposure method according to claim 1, wherein said first determining step is determined based on a pattern to be drawn in each subfield. 3. The method according to claim 1, wherein the calculating step includes calculating the exposure time based on a number of times of setting of the plurality of electron beams in the main field, a settling time, and a settling wait time. An electron beam exposure method according to 1 or 2. 4. The electron beam exposure method according to claim 1, wherein said second determining step includes a step of determining a moving speed of said stage for each main field. 5. The moving speed of the main field having a high moving speed such that a difference between the determined moving speeds of the main fields adjacent in the continuous moving direction is equal to or less than a predetermined value. 5. An electron beam exposure method according to claim 4, further comprising the step of re-determining a value lower than the determined moving speed. 6. A frame composed of a plurality of main fields is drawn by sequentially drawing a plurality of main fields arranged in a continuous movement direction, and a plurality of frames arranged in a direction orthogonal to the continuous movement direction are sequentially drawn. 4. The electron beam exposure method according to claim 1, further comprising the step of drawing, wherein said second determining step includes determining a moving speed of said stage for each frame. 7. A device manufacturing method, wherein a device is manufactured using the electron beam exposure method according to claim 1. 8. An electron beam exposure apparatus for drawing a pattern on an object to be exposed using a plurality of electron beams, a stage for mounting and moving the object to be exposed, Deflecting means for deflecting the surface, irradiation control means for individually controlling irradiation of each electron beam for each deflection, and deflecting a plurality of electron beams on the surface to be exposed by the deflecting means while continuously moving the stage. Then, the irradiation control means individually controls the irradiation of each electron beam for each deflection, and draws a pattern in an element exposure area for each electron beam to draw a subfield composed of the plurality of element exposure areas. By deflecting a plurality of electron beams by the deflecting means and sequentially drawing a plurality of subfields arranged in a direction orthogonal to the continuous moving direction, the plurality of electron beams are deflected. A plurality of main fields arranged in the continuous movement direction by deflecting a plurality of electron beams by the deflecting means, and drawing at least one subfield of at least one main field. At the deflection position where at least one of the plurality of electron beams is irradiated, the plurality of electron beams are settled by the deflection means, and at the deflection position where all of the plurality of electron beams are cut off, the field is set by the deflection means. Control for deflecting the plurality of electron beams without settling and controlling the moving speed of the stage to a moving speed at which the corresponding main field can be exposed within the exposure time of the main field based on the exposure time of each main field. And an electron beam exposure apparatus. 9. The electron beam exposure apparatus according to claim 8, wherein said control means switches a moving speed of said stage when a main field to be drawn changes. 10. The apparatus according to claim 9, wherein, when switching the moving speed of the stage, the control means controls the moving speed of the stage so that a difference between the moving speeds becomes equal to or less than a predetermined value. Electron beam exposure equipment. 11. The control means draws a frame composed of the plurality of main fields by deflecting a plurality of electron beams by the deflecting means and sequentially drawing a plurality of main fields arranged in a continuous movement direction. ,
9. The method according to claim 8, further comprising: sequentially stepping the object to be exposed by the stage to draw a plurality of frames arranged in a direction orthogonal to the continuous movement direction, and switching a moving speed of the stage when a frame to be drawn changes. Electron beam exposure equipment. 12. The deflecting means has an electrostatic deflector and an electromagnetic deflector, and the control means is configured to deflect the plurality of electron beams in the element exposure area by using the electrostatic deflector. 12. The electron beam exposure apparatus according to claim 8, wherein when the plurality of electron beams are deflected from one subfield to the next subfield using a deflector, the electromagnetic deflector is used. 13. A device manufacturing method, wherein a device is manufactured using the electron beam exposure apparatus according to claim 8.