JPH07211614A - Method and system electron beam lithography - Google Patents

Abstract

PURPOSE:To provide method and system for electron beam lithography based on frame scanning suitable for writing a relatively simple figure in which a relatively wide writing range is realized at low cost using an existing conventional scanning electron microscope without requiring any modification in the body thereof. CONSTITUTION:A scan synchronizing section 20 predicts the density of irradiating current within a scanning frame under control of a figure processor 10 and generates a gradation figure split into various degrees of gradation. Frame scanning is then performed for all gradations such that the time staying in a pixel will be constant at each gradation. Electron beam scanning is performed by means of a deflection coil DF in a scanning electron microscope 30 and selection of a specific gradation is made by driving an electronic shutter SH.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam drawing method, and more particularly to an electron beam drawing method suitable for drawing a relatively simple figure and can be realized at a low cost. Furthermore, the present invention also relates to an electron beam drawing system based on the electron beam drawing method.

[0002]

2. Description of the Related Art This type of electron beam drawing apparatus is used to form an exposure mask for an exposure apparatus or to draw an electronic circuit or a circuit element directly on a semiconductor element. As is well known, as an electron beam drawing apparatus, a drawing apparatus by a vector scanning method that sequentially scans and draws electron beams in accordance with various figures to be drawn, and an electron beam that scans in the horizontal and vertical directions. A drawing device based on a frame scanning method similar to the so-called television scanning method is known.

These drawing apparatuses have been developed for drawing actually used semiconductor elements or fairly complicated circuits for experiments. Therefore, these drawing apparatuses are required to have a large storage capacity for storing complicated figures and to perform a high-speed drawing process. Therefore, an electron beam drawing apparatus based on the normal vector scanning method is used.

However, there is a demand for making a semiconductor circuit having a relatively small number of circuit elements or a simple figure on a laboratory scale. In that case, you don't want or need to spend a lot of money. When a commercially available simple scanning electron microscope is used as it is without modification and a figure is drawn within the range of 0.5 μm point or line resolution, the maximum figure range that can be drawn is about 100 μm ² . Compared to this simple type scanning electron microscope that uses one-step electron beam deflection, the above-mentioned drawing is performed in the electron beam scanning device with a four-pole / one-step or eight-pole / two-step deflection developed exclusively for electron beam drawing. Under the conditions, the maximum allowable figure range is about 500 μm ² and about 2 mm ² , respectively. The reason for deciding this range is actually due to the deflection aberration of the electron beam, and when the traveling direction of the electron beam is largely deflected, the electron beam focused in a dot shape on the drawing target is distorted accordingly. This is because the current density of the electron beam incident on the drawing object is reduced at the edge portion. Besides, if the deflection angle is large,
This is because the transmittance of the electron beam in the electron optical system also decreases due to the diaphragm or the like.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to draw a relatively simple figure, and to use a normal scanning electron microscope held by a user, without making any modification to the main body of the electron microscope, to reduce the It is an object of the present invention to provide an electron beam drawing method based on frame scanning and an electron beam drawing system which executes this method, which can realize a relatively wide drawing range at a low cost.

[0006]

The above-mentioned problems are solved by the present invention.
Input the figure data and divide the figure into individual figure elements.
The type, coordinates, and location of the figure elements that are solved to characterize this figure.
Frame pattern data for electron beam scanning consisting of required parameters
Figure processing device 10 for outputting a desired drawing on the drawing object SP
Scanning electron microscope that draws by irradiating an electron beam according to an image pattern
Scanning supplied from the microscope 30 and the graphic processing device 10.
Create a desired drawing figure based on the frame figure data
Therefore, the electronic shutter SH of the scanning electron microscope 30 is
The blanking output signal to operate and the deflection coil DF
Using the scanning synchronization processing unit 20 which outputs a deflection scanning signal,
The object to be drawn when scanning with an initial electron beam of constant intensity
Of the electron flow density reaching each individual scan area of
Multiple gradations A depending on the value of the convection density_0,A_1,A₂To ...
The boundary line S of each individual gradation region in the scan frame is divided._0,
S_1,S₂A gradation processing device that creates ...
The original drawing and the floor where the figure to be processed in 10 is input
It is a tonal figure and has gradation A_0,A_1,A₂Almost the same depending on
Electron beam scanning speed so that each scanning area is irradiated with the same amount of current
Degree C_0,C_1,C ₂... for each gradation A_0,A_1,A₂To ...
The electron beam scanning position within the frame.
The electron beam can be emitted only when it is in the enclosure and the desired drawing figure.
The electronic shutter SH, and
The deflection coil DF is scanned at the corresponding electron beam scanning speed,
Electron beam scanning of all gradations A_0,A_1,A₂Against
It is solved by the electron beam drawing method.

Further, according to the present invention, the above-mentioned problem is in the electron beam drawing method described above, and the scanning synchronization processing unit 20
1 from the original drawing data supplied from the graphic processing device 10.
An original data generator 42 for creating an original drawing for a frame, an original drawing memory 44 following this, and a gradation graphic data generation for creating a gradation graphic for one frame from the gradation graphic data supplied from the graphic processor 10. Based on the input signal of the gradation and the scan start and scan end signals supplied from the device 43, the gradation graphic memory 45 following this, and the graphic processor 10.
A timing circuit 47 for generating a scanning speed corresponding to each gradation, a scanning signal generator 48 following the timing circuit 47, and a scanning signal generator 48 for generating a scanning drive signal for driving the deflection coil DF from an output signal of this circuit 47, and an original drawing memory device. 44, gradation figure memory 45 and timing circuit 47,
This is solved by providing a blanking output circuit 46 that outputs a blanking output signal to the electronic shutter SH from these output signals in accordance with the corresponding gradation degree of each scanning position in the frame.

Further, according to the present invention, the above-mentioned problem is in the electron beam drawing method described above, and the scanning synchronization processing unit 20
1 from the original drawing data supplied from the graphic processing device 10.
A figure generator that creates an original drawing for frames and creates a gradation graphic for one frame from the gradation graphic data, and is supplied from the original drawing memory 44 and the gradation graphic memory 45, which are subsequent thereto, and the graphic processor 10. A timing circuit 47 and a timing circuit 47 that generate a scanning speed corresponding to each gradation based on an input signal of a gradation level and a scanning start and scanning end signal, and drive a deflection coil DF from an output signal of this circuit 47. Connected to the scanning signal generator 48 for generating the scanning drive signal, the original drawing memory 44, the gradation figure memory 45 and the timing circuit 47, and from these output signals, the corresponding floor of each scanning position in the frame. This is solved by the provision of a blanking output circuit 46 for outputting a blanking output signal to the electronic shutter SH according to the adjustment.

Further advantageous configurations according to the invention are described in the dependent claims.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail with reference to the drawings showing the embodiments. FIG. 1 shows the entire system of an electronic drawing system according to the present invention. This system is roughly divided into three groups. That is, the main image processing unit 10, the image sweeping unit 20, and the scanning electron microscope 30 on hand. In this case, the scanning electron microscope 30 is an ordinary scanning microscope and is not the subject of the present invention per se.

The main image processing unit 10 displays, for example, an input unit 2 including a keyboard and switches, a graphic data or various other data, and a display unit 4 capable of monitoring the input data at the time of input 4, and a large amount of data to be stored. Graphic parameters and command data related to the graphic parameters are input from the external storage device 6 such as a floppy disk, a hard disk or the like and the input section 2 for temporarily storing the data and retrieving the desired image data after the desired image data. Output to the control unit (details will be described below), various storage devices (RAM, ROM) for storing required data and programs of control sequences, microprocessors for controlling digital operations, various I / Os. It is composed of a graphic processing body 9 having an O interface and the like. The main image processing unit 10 may be composed of an ordinary personal computer or a personal computer dedicated to graphic processing.

The scanning synchronization processing unit 20 outputs a scanning signal and a blanking output signal for controlling the scanning electron microscope 30 according to the output from the main image processing unit 10, as will be described in detail later, and the scanning electron microscope 30 It is for measuring the irradiation current at 30 and is the main component of this invention.

As described above, the scanning electron microscope 30 may be an ordinary simple type scanning electron microscope, and FIG. 1 shows only main parts directly related to the present invention. The electrons emitted from the electron gun G are focused by the two focusing lenses L ₁ and L ₂ and focused on the surface of the drawing object SP. Thus, in the ideal case, the electron optical axis OA
The electron beam that passes through is deflected so as to be deviated from the electron optical axis OA by driving the deflection coil driving circuit 24 and the corresponding deflection coil DF. Therefore, the electron beam moves on the drawing target SP by a distance x from the electron optical axis OA. Although not shown, another deflection coil and another deflection coil drive circuit are also provided so that the deflection can be performed in the y direction which is orthogonal to the x direction. An electronic shutter SH corresponding to a beam stopper further driven by the blanking output signal to prevent the electron beam from entering the drawing object SP
And its drive circuit 22 are provided. Besides, an ammeter 26 is also provided in the scanning electron microscope 30 in order to measure the current incident on the drawing target SP.

Before entering a detailed description of the circuit of the scan synchronization processing section 20 which is important in the present invention, the basic principle of the drawing method according to the present invention will be described first. As already described, the irradiation current density decreases due to the deflection aberration and the restriction on the device due to the scanning of the electron beam at the edge portion of the scanning range. A schematic graph in which the distribution of the irradiation current density is measured is shown in FIG. 2a. When the current densities I are illustrated on the z-axis with the electron optical axis OA as the origin and the x and y directions orthogonal to each other are respectively set, a bell-shaped irradiation current density is generated as shown in FIG. 2a. As is well known, the curing degree of the electron beam resist irradiated at the time of drawing, or the removal rate when the semiconductor is shaved by electron beam irradiation increases with the irradiation current density. According to FIG. 2a, the region A ₀ of the strongest irradiation current density is in the vicinity of the electron optical axis OA, and the regions A _1, A _2, ... A ₅ occurs. Therefore, in order to keep the curing degree of the electron beam resist or the removal rate by electron beam irradiation almost constant in any irradiation region, the irradiation current is increased as the irradiation region deviates from the electron optical axis OA, or the dwell time of the scanning line is increased. Need to be long. It is considerably difficult to increase or decrease the irradiation current with a fast response speed. Therefore, according to the present invention, maintaining the irradiation current density constant with respect to the irradiation region is achieved by increasing the dwell time of the electron beam, that is, by increasing the scanning time in that region. There is.

Therefore, as shown in FIG. 2b, individual irradiation
Current density area A_0,A_1,A_2,... A_FiveIrradiation equivalent to
Area figure B_0,B_1,B₂(Subsequent items are omitted in the drawings.
Are prepared corresponding to the figure area to be actually drawn.
And area A_0,A_1,A₂Ratio of average irradiation current density in
Is, for example, 1.00, 0.98, 0.96, the irradiation area B _0,
B_1,B₂Adjust the ratio of stay time in 1.00, 1.02, 1.04
To adjust. Limit values of these stay time ratios, gradations, etc.
Of the electronic resist used or the material to be ablated with an electron beam.
It is appropriately determined according to the type and the intensity of the incident current.

For example, as shown in FIG. 3, three vertices α,
In the drawing that fills the inside of the triangle formed by β and γ, the scanning time is changed for each circle according to the concentric circle centered on the point O corresponding to the electron optical axis OA, that is, the outer circle Drawing is performed while making the scanning time longer and scanning in the x direction. Using the example explained above, the ratio of the dwell time of electron beam scanning is 1.00 for the innermost circle (circle), 1.02 for the next adjacent outer circle (triangle), and next for the next outer circle (cross). It is 1.04.

In the drawing according to the present invention, when a triangle as shown in FIG. 3 is drawn, it does not have to be completed by a single scan, that is, a single scan in the vertical (y) direction, and the number of gradations selected matches. Drawing is completed by the number of times of scanning, that is, in the case of FIG. For this purpose, for example, as shown in FIG. 5, electron beam scanning having different scanning times in the x direction is prepared. That is, the electron beam is scanned at a constant speed in the x direction from the starting point 0 to the ending point L _{M of} the figure. This scanning speed is the first scanning speed C _0, the second scanning speed C _1, the third scanning speed C ₂ ·
・ ・ It becomes late in order.

The operation to be actually performed to draw the figure of FIG. 3 will be described with reference to FIGS. 1, 2b and 4. In the first scanning, the electron beam is scanned horizontally, that is, in the x direction at the slowest scanning speed, that is, the scanning speed C ₀ in FIG. That is, a scanning deflection signal of a sawtooth waveform corresponding to the scanning speed C ₀ of FIG. 4 is supplied to the scanning coil drive circuit 24 from the scanning drive signal output end of the scanning synchronization processing unit 20 of FIG. 1 via the conductor L ₁₂ . The current-amplified drive signal is supplied to the deflection coil DF. At this time, the electronic shutter SH is opened only in the hatched area B ₀ of FIG. 2B to allow the electron beam to pass therethrough, and in the non-hatched area, the electronic shutter SH is closed to block the passage of the electron beam ( Actually, the electron beam is largely deflected by a kind of electrostatic deflection plate provided in the scanning electron microscope as the electronic shutter SH). In this operation, the shutter signal is sent from the blanking signal output end of the scanning synchronization processing section 20 of FIG. 1 to the blanking drive circuit 22 via the conductor L ₁₁ , and the drive circuit 22 accordingly responds to the electronic shutter SH. Is performed by applying a predetermined potential for blanking. In this first scanning, the irradiation electron beam reaches only the circle in the central circle portion of the triangle αβγ in FIG.

Next, as the second scan, a sawtooth scan signal corresponding to a slow scan speed C ₁ (FIG. 4) is supplied to the scan coil drive circuit 24 and the deflection coil DF, and at the same time, as shown in FIG. 2b.
The shutter signal is sent to the blanking drive circuit 22 via the conducting wire L ₁₁ so that the electron beam can pass only in the donut-shaped hatching area of the area B ₁ of FIG.
A predetermined potential for blanking is applied to. By this operation, the electron beam reaches only the area of the concentric triangular mark of the triangle αβγ in FIG.

Similarly, as the next third scan,
A scanning signal having a sawtooth waveform corresponding to a slower scanning speed C ₂ (FIG. 4) is supplied to the scanning coil drive circuit 24 and the deflection coil DF, and at the same time, the electron beam is emitted only in the donut-shaped hatched area of the area B _{2 in} FIG. 2B. A shutter signal is sent to the blanking drive circuit 22 via the conductor L ₁₁ so as to allow passage.
A predetermined blanking potential is applied to the electronic shutter SH. By this operation, the electron beam reaches only the area of the concentric circular cross mark of the triangle αβγ in FIG.

Thereafter, the same scans of the fourth, fifth, and sixth times sequentially draw the concentric square mark, the x mark, and the double circle mark region of the triangle αβγ, and finally the triangle αβγ.
Drawing of all areas is completed.

From the above description, it is possible to understand the functions required of the scanning synchronization processing section 20 which plays a major role in the present invention, and the input signals necessary for the drawing process and the input signals for these are arithmetically processed and formed. Output signal can be specified. And
It is also necessary to equip a storage device (usually a dynamic RAM) for temporarily storing the input signal and retrieving it when necessary.

As the input signal, first, the information of the original drawing necessary for drawing, that is, in the case of FIG. 3, the input signal for the parameter for designating the coordinates of the vertices of the triangle αβγ and the three straight lines connecting them (the conductor line in FIG. 1). L ₁ ), and then the coordinates of the boundary line that divides the gradient region, that is, the circle S _0,
An input signal for mapping the coordinates of S _1, S _2, ... (input from conductor L _{2 in} FIG. 1) and an input signal for determining the timing of the scanning signal (input from conductor L _{3 in} FIG. 1) To do) is necessary. In addition, in order to measure the distribution characteristic of the irradiation current (current density distribution chart of FIG. 2A), the lead wire L _{13 is} fed from the ammeter 26 provided in the scanning electron microscope 30.
There is an input signal of a current value input via.

The output signals include the blanking signal for the electronic shutter SH and the excitation signal for the deflection coil DF, which are output via the conductors L ₁₁ and L ₁₂ , respectively, which have already been described in detail above. In addition, the measured irradiation current is AD-converted and then stored by specifying the address corresponding to the pixel, and there is also an output signal that is output to send the stored value to the image processing apparatus 10. In addition, the conductors L _1, L ₂ and L
_{The 3} is capable of bidirectional transmission as described later.

Output signals corresponding to the original drawing to be drawn supplied from the graphic processing body 9, that is, the original drawing is decomposed into a large number of graphic elements, and a command for specifying these elements (for example, straight line, circle, arc, Triangle, quadrangle, rectangle, etc.) and the coordinates of the starting point and attached parameters (for example, straight line length,
The radius of the circle, the length of the side of the polygon, etc.) is introduced from the conductive line L ₁ to the original drawing data generation unit 42 of the scanning synchronization processing unit 20. The original drawing data generation unit 42 sets the entire scanning area as one frame based on the generated original drawing data, and creates image information for this frame. That is, binary information indicating whether or not to draw each pixel in a frame (for example, a digital value that is 1 when electron beam irradiation is performed and is 0 when electron beam irradiation is not performed) is serialized according to, for example, the x-direction scanning direction. create. The created information is sequentially introduced and stored in the next original drawing storage device 44.

Next, gradation information, that is, the boundary line S in FIG.
_A gradation boundary figure consisting of _0, S _1, S _2, ... (The creation of this figure will be described in the next step) is decomposed into each image element by the same procedure as the original drawing and is attached with the image element designation command. The parameter is introduced from the graphic processing main body 9 to the gradation graphic data generating section 43 of the scanning synchronization processing section 20 from the graphic processing main body 9 through the conducting wire L ₂ . Then, similarly, image information for one frame is introduced into the gradation figure storage unit 45 and stored.

The gradation boundary graphic is created by the following procedure.
Before drawing, the intensity of the electron beam reaching the entire scanning region is measured with a scanning electron microscope used in advance. The intensity of this electron beam is used as a current value from the ammeter 26 to the scan synchronization processing unit
0 is supplied to the analog / digital converter 50, and is converted into a digital value here, and is introduced into the graphic processing body 9 through the conductor L ₄ to create current density distribution information corresponding to FIG. 2a.
This distribution information is returned to the scanning synchronization processing unit 20 again and stored in the current density distribution storage device 49 for one frame. If necessary, the stored current density distribution information is taken out and sent to the figure processing body 9, where the number of gradation steps, gradation width, etc. are selected according to the electron beam resist or the material to be drawn, and the input section is selected. Boundary lines S _0, S _1, of the above-described gradation graphic are made by the parameters input from 2 and the sequence control program stored in the control memory (eg ROM or external memory 6) of the graphic processing body 9 _. Create S _2, ...

The timing circuit 47 of the scan synchronization processing section 20.
The x-direction scanning start trigger pulse and the gradation signal indicating the gradation of the step are introduced from the graphic processing body 9 through the conducting wire L ₃ . In the timing circuit 47, the necessary scanning speed (C _0, C _1, C _2, ...
The scanning time in the x direction, which is determined by any one of the above), is calculated, and a predetermined digital value, for example, "1" is continuously output during this period. At that time, the end point of the x-direction scanning is calculated, and the x-direction scanning end pulse is formed. This x-direction scanning end pulse is used as a start trigger pulse for x-direction scanning of the next adjacent scanning line, and becomes a signal corresponding to one step of y-direction scanning. The predetermined digital value is introduced into the blanking output circuit 46, which will be described below, and at the same time, is introduced into the x-direction scanning signal generator 48. Here, during the duration of the predetermined digital value, a constant voltage generated from a digital / analog converter (not shown) is time-integrated and converted into a sawtooth waveform voltage. It is convenient to use a well-known analog current-voltage conversion circuit (not shown) for the integration. The scanning speed is changed by changing the constant voltage value from the digital-analog converter.

Whether or not the scanning electron beam is used for drawing is determined by the blanking output signal of the blanking output circuit 46. As described above, when the blanking output signal is "H", the electronic shutter SH is turned on to make the electron beam non-transparent, and when the blanking output signal is "L", the electronic shutter SH is turned off to make the electron beam transparent. Yes (or vice versa). Blanking output circuit 46
Determines whether the blanking output signal is "H" or "L" for each pixel during the scanning period, and supplies it to the drive circuit 22 of the electronic shutter SH. The blanking output signal used for the above determination is based on the two-dimensional address of the pixel to be scanned (determined by the scanning time in the x direction and the trigger pulse for the y direction scanning) formed in the timing circuit 47, and the original drawing memory unit 44. And the stored value in the corresponding pixel of the gradation figure memory 45.

An original figure data generator 42 and a gradation figure generator 43 used in the scan synchronization processing section 20 according to the present invention.
Can be configured with commercially available integrated circuits for graphic controllers, for example, μPD 72123 (NEC). Further, each of the original drawing memory 44, the gradation figure memory 45 and the current density distribution memory 49 can be constituted by one or more readable large capacity memory, for example, a dynamic RAM.

In the above description, the address generation circuit or the monitoring circuit, the clock circuit required for various timings,
The description of the memory control circuit and the like has been omitted. This is because the description of these parts may rather complicate and confuse the contents of the main part of the present invention. Since the functions on the circuit have been described in sufficient detail, those skilled in the art can easily assume the configuration of the circuit.

The present invention can be variously modified or modified based on what has been described. For example, the two graphic generators 42 and 43 of FIG. 5 are formed by only one graphic controller, the original drawing data and the gradation graphic data are processed separately with the help of the control program and stored in the corresponding memory 44 or 45. You can also do it. In this case, the conductors L _1, L
₂ can be composed of one bus line.

In any case, it goes without saying that all the methods and devices having the configurations defined in the claims are within the scope of the present invention.

[0034]

As described above, the electron beam writing method according to the present invention and the electron beam writing system for carrying out the method are composed of a scanning electron microscope which can be obtained by hand or at low cost, and a CAD or a personal computer. An electron beam drawing of a relatively complicated figure can be performed at a low cost by using an image processing apparatus and by simply adding a simple electronic circuit device according to the present invention without modifying the scanning electron microscope.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall arrangement of an electron beam drawing system of the present invention.

FIG. 2 is a graph (a) showing a map of measured irradiation current density values and a drawing (b) showing regions corresponding to each gradation of the irradiation current density.

FIG. 3 is a diagram showing regions of different scanning speeds with respect to an original diagram.

FIG. 4 is a graph showing various horizontal scanning velocities that are selectively used according to the gradation level (the horizontal axis is the horizontal length corresponding to the entire screen).

FIG. 5 is a detailed block diagram of a scan synchronization processing unit used in the electron beam drawing system according to the present invention.

[Explanation of symbols]

2 input unit 4 display device 6 external storage device 9 graphic processing body 10 graphic processing device 20 scanning synchronization processing unit 30 scanning electron microscope 22 electronic shutter drive unit 24 deflection coil drive unit 26 ammeter SP drawing object SH electronic shutter DF deflection coil L _1, L _2, L _3, L _4, L _11, L _12, L _13, Conductor S _0, S _1, S ₂ Gradation boundary 42, 43 Graphic generator 44, 45, 49 Storage device 46 Blankingun output circuit 47 Timing Circuit 48 Scanning Signal Generator 50 Analog / Digital Converter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01J 37/22 502 B

Claims (6)

[Claims] 1. An individual figure is required for the figure by inputting the figure data.
The type of graphic element that characterizes this shape by disassembling it
A frame figure for electron beam scanning consisting of marks and required parameters
Figure processing device (10) for outputting data, drawing object
(SP) draws by irradiating an electron beam according to the desired drawing figure
Scanning electron microscope (30) and graphic processing device
Based on the scanning frame graphic data supplied from (10)
Then, in order to form a desired drawing figure, the scanning electron microscope is used.
A blank to activate the electronic shutter (SH) of the mirror (30).
King output signal and deflection scan signal to deflection coil (DF)
Electron beam drawing using scanning synchronization processing unit (20) for outputting and
In the drawing method, when scanning with an initial electron beam of constant intensity, the drawing target
Of the electron flow density reaching each individual scan area of
Multiple gradations (A_0,A_1,A ₂・ ・
・), And the boundary of each individual gradation area in the scanning frame
Line (S_0,S_1,S₂..) was created, and the figure to be processed in the figure processing device (10) was input.
The original drawing and the gradation figure are the gradation (A_0,A_1,A₂...) almost the same current density
The electron beam scanning speed (C_0,
C_1,C₂...) for each gradation (A_0,A_1,A₂...)
Then, the electron beam scanning position is set to the gradation range and the desired drawing in the frame.
Only when it is in the figure, the electronic sha
Switch (SH) is activated,
The deflection coil (DF) is scanned at the sagittal line scanning speed, and the above-described electron beam scanning is performed for all gradations (A_0,A_1,A₂...)
An electron beam drawing method comprising: 2. The predicted electron flow density is obtained in advance from the measurement signal of the ammeter (26) before drawing, and the gradation is determined according to the degree of electron beam interaction of the electron beam resist or the drawing object (SP). The electron beam drawing method according to claim 1, wherein the electron beam drawing method is determined. 3. The predicted electron flow density is empirically determined, and the gradation is an electron beam resist or an object to be drawn (SP).
The electron beam drawing method according to claim 1, wherein the electron beam drawing method is determined according to the degree of the electron beam interaction. 4. An electron beam drawing system for executing the electron beam drawing method according to claim 1, wherein original scanning data supplied from a figure processing device (10) to a scanning synchronization processing unit (20). An original data generator (42) for creating an original for one frame, and an original memory (4) following this.
4), a gradation graphic data generator (43) for creating a gradation graphic for one frame from the gradation graphic data supplied from the graphic processing device (10), and a gradation graphic storage device (45) following this. A timing circuit (4) for generating a scanning speed corresponding to each gradation based on the gradation input signal and the scanning start and scanning end signals supplied from the graphic processing device (10).
7), following the timing circuit (47), this circuit (4
A scanning signal generator (48) for generating a scanning driving signal for driving the deflection coil (DF) from the output signal of 7), an original drawing memory (44), a gradation figure memory (45) and a timing circuit (47). And from these output signals,
An electron beam drawing system characterized in that a blanking output circuit (46) for outputting a blanking output signal is provided to an electronic shutter (SH) according to a corresponding gradation degree of each scanning position in a frame. 5. An electron beam drawing system for executing the electron beam drawing method according to claim 1, wherein original scanning data supplied from a figure processing device (10) to a scanning synchronization processing unit (20). A figure generator that creates an original figure for one frame and creates a gradation figure for one frame from gradation figure data, and an original figure memory (44) and a gradation figure memory (45) following this, a figure process The timing circuit (47) and the timing circuit (47) for generating the scanning speed corresponding to each gradation based on the gradation input signal and the scanning start and scanning end signals supplied from the device (10) A scanning signal generator (48) for generating a scanning driving signal for driving the deflection coil (DF) from the output signal of the circuit (47),
And an original shutter memory (44), a gradation figure memory (45), and a timing circuit (47), and from these output signals, an electronic shutter according to the gradation corresponding to each scanning position in the frame. An electron beam drawing system comprising a blanking output circuit (46) for outputting a blanking output signal to (SH). 6. The scanning synchronization processing unit (20) further includes an analog / digital converter (50) for converting a current value from the ammeter (26) of the scanning electron microscope (30) into a digital value.
6. An electron beam drawing system according to claim 4, further comprising a storage device (49) for storing the current value for each pixel in the frame.