JPH10308341A - Exposing method and aligner by means of electron beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bring the lithography condition of every irradiation of an electron beam into an appropriate state, by a method wherein an evaluated value of the amount of movement of the focul position of the electron beam for every group of the electron beam is computed, and the focul position of the corresponding electron beam of the electron beam group is corrected. SOLUTION: The arrangement position to be set is selected (S101), and the number of electron beams to be projected on a wafer without interruption by subarrays is detected (S102). Then, a distribution coefficient C1 is computed for every subarray (S103), and the distribution coefficient C1 computed for every subarray is stored as refocus control data (S104). Then, the treatment on all arrangement positions to be set is finished (S105), and an evaluation treatment is finished (S106). The intermediate image forming position of an element electronic optical system is controlled for every subarray, based on the refocus control data as an element of the distribution coefficient C1 for every subarray as an element.

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 In an electron beam exposure apparatus which performs exposure by forming an electron beam on a substrate, if the beam current is large, the electron beam image projected on the substrate is blurred due to the Coulomb effect. Most of the blur due to the Coulomb effect can be corrected by re-adjusting the focal position of the reduction electron optical system for electron beam projection, but a part remains without being corrected. In a variable-shaped exposure apparatus that transfers the electron beam by shaping the cross-sectional shape of the electron beam within a range of at most about 10 μm square, the area of the formed beam and the device parameters (beam current density, beam incident half angle, beam acceleration voltage and reduction) The blur due to the Coulomb effect is predicted from the optical length of the electron optical system), and the focus of the reduced electron optical system is adjusted according to the prediction result.

Meanwhile, a plurality of electron beams are arranged and irradiated on a substrate, the plurality of electron beams are deflected to scan the substrate, and the irradiation of the plurality of electron beams is individually performed according to a pattern to be drawn. In a multi-electron beam type exposure apparatus that writes patterns on / off, the electron beam is dispersed and arranged, that is, the effective current density per unit area on the substrate is low, so the Coulomb effect The blur due to is small. This means that when blurring due to the Coulomb effect is limited to within a predetermined value, the multi-electron beam type exposure apparatus can provide a larger beam current than the variable-shaped type exposure apparatus, thereby improving the exposure throughput.

[0004]

However, even in the multi-electron beam type exposure apparatus, depending on the pattern to be drawn, the case where the electron beam irradiated on the substrate is concentrated in a narrow area and the case where the electron beam is irradiated on the substrate are different. In some cases, the beam is uniformly dispersed. Then, even if the number of irradiated electron beams is the same, the former has a higher effective current density per unit area than the latter, so that the blur due to the Coulomb effect is large.

For example, as shown in FIGS. 14 (A) and 14 (B), the number of electron beams applied to the substrate (equivalent to the sum of currents applied to the substrate). (B), the plurality of electron beams are concentrated in a narrower area than in (A), so that the blur due to the Coulomb effect increases. , (B), the blur due to the Coulomb effect is reduced because (A) has only one electron beam for four electron beams. That is, FIG.
In (B), the blur due to the Coulomb effect varies depending on the location. Therefore, simply performing focus adjustment based on the number of electron beams for each irradiation or the sum of currents applied to the substrate cannot correct blur caused by the Coulomb effect accurately.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-electron beam type exposure apparatus capable of realizing higher resolution drawing than before by optimizing drawing conditions for each electron beam irradiation for correcting blur due to the Coulomb effect. It is in.

[0007]

According to an aspect of the present invention, there is provided an electron beam exposure method for exposing a pattern on a base slope using a plurality of electron beams. Arranging a plurality of electron beam groups composed of electron beams and forming an image on the substrate via a reduction electron optical system; deflecting the plurality of electron beam groups on the substrate; Independently controlling the irradiation of each electron beam, and forming an image of the electron beam for each electron beam group based on the number of electron beams for each deflection applied to the substrate for each electron beam group. The method includes an evaluation step of calculating an evaluation value relating to a movement amount of a position, and a correction step of correcting an imaging position of an electron beam of a corresponding electron beam group based on the evaluation value.

In the correcting step, the image forming positions of the electron beams of all the electron beam groups are corrected by an average value of the correction amounts of the electron beam groups, and the correction amount and the average value of each electron beam group are corrected. And correcting the imaging position of the electron beam for each corresponding electron beam group by the difference from the above.

In the evaluation step, the distance between the electron beam group whose evaluation value is calculated and another electron beam group, and the number of electron beams irradiated on the substrate of the other electron beam group are further determined. The evaluation value is calculated based on the evaluation value.

Each of the electron beams is an electron beam from an intermediate image of the corresponding electron source, and the correcting step includes setting an image forming position of the intermediate image in the optical axis direction of the reduction electron optical system with the electron beam. The method is characterized in that the method includes a step of correcting each group.

In the correcting step, in the predetermined deflection area, the imaging position of the electron beam of the corresponding electron beam group is corrected based on the evaluation value for each of the plurality of electron beam groups in the deflection area. Is performed.

One embodiment of the electron beam exposure apparatus according to the present invention is an electron beam exposure apparatus for exposing a pattern on a base slope using a plurality of electron beams. A reduction electron optical system that forms an image on the substrate, a deflecting unit that deflects the plurality of electron beams on the substrate, and an irradiation control unit that individually controls irradiation of each electron beam for each deflection. Correcting means for correcting an image forming position of an electron beam for each of the electron beam groups; and calculating the electron beam based on the number of electron beams for each deflection applied to the substrate for each of the electron beam groups. Means for storing an evaluation value relating to the amount of movement of the imaging position of the electron beam for each group; and correcting the imaging position of the electron beam of the corresponding electron beam group by the correction means based on the evaluation value. And having a that control means.

The evaluation value is calculated based on a distance between the electron beam group for which the evaluation value is calculated and another electron beam group and the number of electron beams irradiated on the substrate of the other electron beam group.
It is characterized by being calculated.

Further, there is provided an element electron optical system array formed by arranging a plurality of subarrays each including a plurality of element electron optical systems for forming an intermediate image of the electron source, wherein each of the electron beams is converted from the corresponding intermediate image of the electron source. Wherein the correction means moves the position of the intermediate image in the optical axis direction of the reduction electron optical system for each of the sub-arrays.

The correction means has a refocus coil for adjusting the focal position of the reduction electron optical system, and the control means controls the electron beams of all the electron beam groups by the average value of the correction amount for each electron beam group. The imaging position of the beam is corrected by the refocus coil.

Each of the elementary electron optical systems corrects an aberration generated when the intermediate image is reduced and projected onto the substrate via the reduction electron optical system.

The control means corrects the imaging position of the electron beam of the corresponding electron beam group in a predetermined deflection area based on the evaluation value for each of the plurality of electron beam groups in the deflection area. Is performed by the correction means.

A device manufacturing method according to the present invention is characterized in that a device is manufactured using the above-described electron beam exposure method or electron beam exposure apparatus.

[0019]

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 1a form a crossover image between the grid 1b and the anode 1c (hereinafter, this crossover image is referred to as an electron source).

Electrons radiated from this electron source are focused on a condenser lens whose front focal position is at the electron source position.
2 makes the electron beam almost parallel. The substantially parallel electron beams enter the elementary electron optical system array 3. The element electron optical system array 3 is formed by 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 on the wafer 5.

At this time, each element of the element electron optical system array 3 is set so that the interval between the electron source images on the wafer 5 is an integral multiple of the size of the electron source image. 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 reduces each intermediate image to the wafer 5 by the reduction electron optical system 4. The aberration that occurs when the image is projected is corrected in advance.

The reduction electron optical system 4 includes a first projection lens 41 (4
3) and the 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 deflector that deflects a plurality of electron beams from the elementary electron optical system array 3 and displaces a plurality of electron source images on the wafer 5 by substantially the same amount of displacement in the X and Y directions. . The deflector 6 includes a main deflector 61 used when the deflection width is wide and a sub deflector 62 used when the deflection width is small.The main deflector 61 is an electromagnetic 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 A1 to A5 are formed. Each subarray is
A plurality of element electron optical systems are two-dimensionally arranged. In each of the sub-arrays of this embodiment, two sub-arrays such as A3 (1,1) to A3 (3,9) are used.
Seven element electron optical systems are formed.

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

In FIG. 3, AP-P is a substrate having an aperture (AP1) which is illuminated by an electron beam made substantially parallel by a condenser lens 2 and defines the shape of the transmitted electron beam. This is a common substrate with the system. 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 elementary electron optical systems. A wiring (W) for turning on / off 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.

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 individually set by the first focus / astigmatism control circuit and can be individually set for each element electron optical system,
The unipotential lens 303b can have different focal lengths in orthogonal cross sections, and can be set individually for each elementary electron optical 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 of the focal length of the condenser lens 2 to the focal length of the electron optical system 303.
The focal point is kept constant, and the principal point is moved to move the intermediate image system formation position. 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 condenser lens 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, and a blanking corresponding to the intermediate image forming position (rear focal position) of the electron optical system 303 or near it. The electrode 301 is located. 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, the electron beam bundle 305 and the electron beam bundle 306 form the reduced electron optical system 4
Have different angular distributions on the object plane, the electron beam bundle 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.
Therefore, the blanking aperture BA that transmits only the electron beam bundle 305 is reduced in the pupil position of the reduced electron optical system (on the P plane in FIG. 1).
It is provided in.

The electron optical system 303 of each element electron optics
Are image field curvatures generated when the intermediate images formed by each are reduced and projected on the surface to be exposed by the reduction electron optical system 4.
In order to correct astigmatism, the potentials of the two intermediate electrodes of each electron optical system 303 are individually set, and the electron optical characteristics (intermediate image formation position, astigmatism) of each element electron optical system are made different. I have. 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 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 1
Reference numeral 5 denotes a control circuit for controlling the electron optical characteristics (intermediate image formation position, astigmatism) of each element electron optical system of the element electron optical array 3 for each subarray.

The second focus / astigmatism control circuit 16 comprises 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 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 synchronously controls the plurality of control circuits and the Faraday cup 10 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 Operation) The operation of the electron beam exposure apparatus of this embodiment will be described with reference to FIG.

When the pattern data to be exposed on the wafer is inputted, the CPU 25 determines the minimum deflection amount given to the electron beam by the sub deflector 62 based on the minimum line width, the type and the shape of the line width of the pattern to be exposed on the wafer. To determine. Next, the data is divided into pattern data for each exposure area of each element electron optical system, a common array composed of array elements FME is set using the minimum deflection amount as an array interval, and the pattern data is divided for each element electron optical system. Convert to data represented on a common array. 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.

6A and 6B, the patterns Pa and P to be exposed by the element electron optical systems a and b adjacent to the deflecting array DM are common.
Indicates b. That is, each of the elementary electron optical systems irradiates the electron beam onto the wafer with the blanking electrode turned off at the hatched arrangement position where the pattern exists.

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.

The first area FF on the array is formed by a plurality of electron beams.
When the electron beam is positioned at the position (1), the electron beam is deflected by the sub-deflector 62 for exposure in units of the minimum deflection amount (array interval), so that all the patterns exposed on the wafer can be exposed. When a plurality of electron beams are located in the second area NN on the array, the electron beams are deflected without being settled, whereby exposure can be performed while reducing unnecessary deflection of the electron beams.

Next, 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. From the data shown in FIGS. 6A and 6B, the on / off of the blanking electrode for each element electron optical system corresponding to the arrangement position where the electron beam is settled is determined.

As a result, as shown in FIG. 7, an exposure control data is prepared in which the arrangement position exposed by at least one electron beam and the on / off of the blanking electrode of each element electron optical system at the arrangement position are elements. I do.

Further, the CPU 25 executes an evaluation process shown in FIG. 8 based on the created exposure control data in order to correct blur due to the Coulomb effect.

In the evaluation process of FIG. 8, a distribution coefficient C for each sub-array representing a distribution state of a plurality of electron beams irradiated on the wafer is calculated for each arrangement position to be settled in the following procedure.

(Step S101) The array position (x,
Select y).

(Step S102) The selected array position (x,
In y), the number N1 to N5 of electron beams irradiated on the wafer without being blocked for each of the subarrays A1 to A5 (the number of blanking electrodes turned off in the subarray) is detected. That is, of the electron beams from the sub-array, which is an electron beam group composed of a plurality of electron beams, how many electron beams are irradiated on the wafer is detected.

(Step S103) As the distribution coefficient Ci of the sub-array Ai, the distribution coefficient Ci for each sub-array is calculated by the following equation.
Ask for.

[0061]

[Outside 1] Here, Ni is the number of electron beams irradiated on the wafer in the subarray Ai detected in step S102, K is a constant determined by the size of the subarray, and Di, j is the center of the subarray Ai and the subarray. It is the distance from the center of Aj.

According to the above equation, even if the number of electron beams irradiated on the wafer is the same, the larger the number of electron beams irradiated on the wafer in the subarray Ai, the more the subarray
The distribution coefficient Ci of Ai increases. Even if the number of electron beams irradiated on the wafer in the sub-array Ai is the same, if the number of electron beams in the other sub-arrays is large, the distribution coefficient Ci of the sub-array Ai increases.

(Step S104) The obtained distribution coefficient Ci for each sub-array is stored as refocus control data.

(Step S105) It is determined whether or not the processing of steps S102 to S104 has been completed for all the array positions (x, y) to be settled, and the unprocessed array positions (x, y) to be settled. If there is, the process returns to step S101 to select an unprocessed settling array position (x, y).

(Step S106) When the above processing is completed for all the array positions (x, y) to be settled, the evaluation processing in FIG. 8 ends, and the sub-arrays for the array positions to be settled as shown in FIG. The refocus control data having the distribution coefficient Ci as an element is stored.

In this embodiment, these processes are performed by the CPU 25 of the electron beam exposure apparatus. However, even if the processing is performed by another processing apparatus, and the exposure control data and the refocus control data are transferred to the CPU 25, the purpose and The effect remains the same.

Next, when the CPU 25 instructs the control system 22 to execute “exposure” via the interface 24, the CPU 25
Executes the following steps based on the data on the memory 23 to which the above-described exposure control data and refocus control data are transferred.

(Step S201) The control system 22 instructs the deflection control circuit 17 based on the exposure control data from the memory 23 transferred in synchronization with the internal reference clock, and the sub-deflector 62 of the deflector 6 A plurality of electron beams from the elementary electron optical system array are deflected to set their positions.

Further, the control system 22 performs the first control based on the refocus control data transferred in the same manner as the exposure control data.
The focus / astigmatism control circuit is commanded to control the intermediate image forming position of the elementary electron optical system for each sub-array. That is, based on the distribution coefficient Ci for each subarray, the intermediate image forming position of the elementary electron optical system of each subarray is set closer to the electron gun 1 as the distribution coefficient C increases. As a result, as the distribution coefficient C increases, the imaging position of the electron beam on the wafer that moves to a position farther from the reduction electron optical system 4 due to the Coulomb effect becomes:
Since it comes closer to the reduced electron electronic optical system 4, blurring due to the Coulomb effect can be corrected. The amount of movement (correction amount) of the imaging position of the electron beam on the wafer is called a refocus amount, and the relationship between the refocus amount and the distribution coefficient C is obtained in advance by numerical simulation or experiment, and is based on the distribution coefficient C. The electron optical characteristics of the element electron optical system for each sub-array are controlled so as to obtain a desired refocus amount.

Further, the control system 22 instructs the blanking control circuit 14 to turn on / off the blanking electrode of each element electron optical system according to the pattern to be exposed on the wafer 5. At this time, the XY stage 12 is continuously moving in the X direction, and the deflection control circuit 17 controls the deflection position of the electron beam including the amount of movement of the XY stage 12.

As a result, the electron beam from one elementary electron optical system scans and exposes the exposure field (EF) on the wafer 5 starting from the black square as shown in FIG. 10A. Also, as shown in FIG. 10B, the exposure fields (EF) of the plurality of element electron optical systems in the sub-array are set to be adjacent, and as a result, the plurality of exposure fields The sub-array exposure field (SEF) composed of (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 A1 to A5 as shown in FIG.

(Step S202) The control system 22 is configured as shown in FIG.
After exposing the subfield 1 shown in (1), the deflection control circuit 17 is instructed to expose the subfield 2, and the main deflector 61 of the deflector 6 deflects a plurality of electron beams from the elementary electron optical system array. At this time, the control system 22
Instructs the astigmatism control circuit to correct the focal position of the reduction electron optical system 4 by controlling the dynamic focus coil 7 based on the previously obtained dynamic focus correction data, and based on the previously obtained dynamic astigmatism correction data. By controlling the dynamic stig coil 8, the astigmatism of the reduction electron optical system is corrected. Then, the operation of step 1 is performed, and the subfield 2 is exposed.

By repeating the above steps S201 and S202,
As shown in FIG. 11B, the subfields are sequentially exposed such as subfields 3 and 4, and the entire surface of the wafer is exposed.

(Second Embodiment) In the first embodiment,
The refocus amount of the electron beam for each sub-array has been set by adjusting the electron optical characteristics of the elementary electron optical system for each sub-array. In the second embodiment, the average value of the refocus amount for each sub-array is set. Is calculated, the refocus amount of the average value is set by the refocus coil 9, and the element electron optical system of each subarray sets the refocus amount of the residual obtained by subtracting the average value from the refocus amount to be set. .

(Third Embodiment) In the first embodiment,
Each time the sub-deflector 62 deflects a plurality of electron beams from the elementary electron optical system array and stabilizes their positions, the refocus amount of the electron beam for each sub-array is changed. However, in the third embodiment, During the exposure of the subfield, the refocus amount of the electron beam for each subarray is kept constant, and when the subfield to be exposed changes, the refocus amount of the electron beam for each subarray is changed. At this time, the distribution coefficient C for each sub-array uses the average value of the distribution coefficient C at each array position in the sub-field to be exposed. In other words, in a predetermined deflection area (subfield), the imaging position of the electron beam for each subarray is corrected based on the evaluation value for each of the plurality of subarrays in the deflection area.

(Embodiment of Device Manufacturing Method) Next, an embodiment of a device manufacturing method using the above-described electron beam exposure apparatus will be described.

FIG. 12 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. 13 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.

[0080]

As described above, according to the present invention, when a pattern is drawn by a multi-electron beam type exposure apparatus, the drawing conditions for each electron beam irradiation for correcting blur due to the Coulomb effect are optimized. As a result, higher resolution drawing than before can be realized.

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

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

FIG. 8 is a diagram illustrating an evaluation process according to the present invention.

FIG. 9 illustrates refocus control data.

FIG. 10 is a view for explaining an exposure field (EF) and a sub-array exposure field (SEF).

FIG. 11 is a diagram illustrating a subfield.

FIG. 12 is a diagram illustrating a flow of manufacturing a micro device.

FIG. 13 is a diagram illustrating a wafer process.

FIG. 14 is a diagram illustrating blurring due to the Coulomb effect.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electron gun 2 condenser lens 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 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

Claims (13)

[Claims] 1. An electron beam exposure method for exposing a pattern on a base slope using a plurality of electron beams, comprising: arranging a plurality of electron beams composed of a plurality of electron beams; Forming an image on a substrate; deflecting the plurality of electron beams on the substrate; individually controlling irradiation of each electron beam for each deflection; and the substrate for each electron beam group An evaluation step of calculating an evaluation value related to a movement amount of an imaging position of an electron beam for each of the electron beam groups based on the number of electron beams for each deflection irradiated above, and an electron corresponding to the electron beam based on the evaluation value. A correcting step of correcting the imaging position of the electron beam of the beam group. 2. The method according to claim 1, wherein the correcting step corrects the imaging positions of the electron beams of all the electron beam groups by an average value of the correction amounts of the electron beam groups. Correcting the imaging position of the electron beam for each corresponding electron beam group by the difference from the average value. 3. The evaluation step further includes the step of calculating a distance between the electron beam group for which an evaluation value is calculated and another electron beam group, and the number of electron beams of the other electron beam group irradiated onto the substrate. 2. The electron beam exposure method according to claim 1, wherein the evaluation value is calculated based on the following. 4. Each electron beam is an electron beam from an intermediate image of a corresponding electron source, wherein the correcting step comprises:
4. The electron beam exposure method according to claim 1, further comprising the step of correcting an image forming position of the intermediate image in the optical axis direction of the reduction electron optical system for each of the electron beam groups. 5. The image forming apparatus according to claim 1, wherein the correcting step includes, in a predetermined deflection area, an imaging position of an electron beam of the corresponding electron beam group based on an evaluation value for each of the plurality of electron beam groups in the deflection area. 2. The electron beam exposure method according to claim 1, wherein the correction is performed. 6. A device manufacturing method, wherein a device is manufactured using the electron beam exposure method according to claim 1. 7. An electron beam exposure apparatus for exposing a pattern on a base slope using a plurality of electron beams, wherein a plurality of electron beam groups composed of a plurality of electron beams are arranged and imaged on the substrate. An electron optical system; a deflecting unit that deflects the plurality of electron beams on the substrate; an irradiation control unit that individually controls irradiation of each electron beam for each deflection; Correction means for correcting the imaging position, calculated based on the number of electron beams for each deflection applied to the substrate for each of the electron beam groups, the imaging position of the electron beam for each of the electron beam groups Means for storing an evaluation value relating to the amount of movement, and control means for causing the correction means to correct the imaging position of the electron beam of the corresponding electron beam group based on the evaluation value. Electron beam exposure equipment. 8. The evaluation value is based on a distance between the electron beam group for which the evaluation value is calculated and another electron beam group, and the number of electron beams applied to the substrate of the other electron beam group. 8. The electron beam exposure apparatus according to claim 7, wherein the values are calculated. 9. An element electron optical system array in which a plurality of subarrays each including a plurality of element electron optical systems forming an intermediate image of an electron source are arranged, and each of the electron beams is converted from a corresponding intermediate image of the electron source. 8. The electron beam exposure apparatus according to claim 7, wherein the correction means moves the position of the intermediate image in the optical axis direction of the reduction electron optical system for each of the sub-arrays. 10. The correction means includes a refocus coil for adjusting a focal position of the reduction electron optical system, and the control means controls all electron beam groups by an average value of correction amounts for each electron beam group. 10. The electron beam exposure apparatus according to claim 7, wherein the image forming position of the electron beam is corrected by the refocus coil. 11. Each of the element electron optical systems corrects an aberration generated when the intermediate image is reduced and projected onto the substrate via the reduction electron optical system. Electron beam exposure equipment. 12. The image forming apparatus according to claim 1, wherein the control unit determines an image forming position of an electron beam of the corresponding electron beam group in a predetermined deflection area based on an evaluation value for each of the plurality of electron beam groups in the deflection area. 8. The electron beam exposure method according to claim 7, wherein said correction is performed by said correction means. 13. A device manufacturing method, wherein a device is manufactured using the electron beam exposure apparatus according to claim 7.