JPH1167643A - Electron beam drawing method and apparatus - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To reduce the raster-line electron beam drawing time when a figure is relatively simple and there is an area that does not include a figure pattern at all in a part of a field. A raster image processing unit sends graphic pattern data from a microprocessor μP, a RAM storage, a ROM storage, a pattern data storage PDM, and a graphic data input operation unit to a pattern data storage PDM for storage. And a raster signal processing unit. The raster image processing unit further includes a control unit SCSI, a blanking signal transmitting unit 26, a horizontal scanning signal generating unit, and a vertical scanning signal generating unit 30. , A scan start position and a scan end position are determined from the data, and a signal processing unit is provided for performing signal processing so as to form a scanning signal and a blanking signal suitable for scanning in a desired scanning area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam lithography method capable of improving the efficiency of electron beam lithography and a small electron beam lithography apparatus suitable for the method.

[0002]

2. Description of the Related Art An electron beam lithography apparatus includes an electron beam focusing / deflecting device comprising an electron beam focusing system and an electron beam deflecting system, a sample stage on which a sample to be written is placed, and a sample moving mechanism comprising a driving unit thereof. And a graphic input device having a CAD function for inputting graphic data. Such an electron beam deflecting system is composed mainly of electrostatic electrodes and has a small distortion even if the scanning range is wide, and can achieve high accuracy and high image forming efficiency. Used in In particular, a dedicated electron beam lithography system that manufactures semiconductor elements costs 10 to 15 per unit.
It will be 100 million yen, and the same cost will be required for the associated equipment to increase the yield and utilization rate. In addition, a single device of about several hundred million yen has been developed for research.

In the fields of semiconductors, electronics, basic physical properties, etc.
Fine patterns such as relatively simple figure electrodes or wiring
The number of researchers who want to create applications has increased in recent years. Soshi
Such researchers, especially at universities and government research institutes.
As mentioned above in a researcher doing progressive work
Very few can prepare the cost of obtaining a suitable device. Fine
Relatively simple and inexpensive power supply suitable for fine pattern prototype research.
A sagittal drawing apparatus has been recently announced. This type of drawing device
Now, based on the currently widely available scanning electron microscope
And digital processing of the desired figure with the aid of CAD
System that combines graphic processing devices
You. Such an electron beam lithography system is not
And the price of one unit is about 30 to 60 million yen.
Wear. In this drawing system, the electron beam is scanned by a scanning electron microscope.
When tilted with respect to the axis or moved away from the optical axis
Take measures to prevent or reduce distortion (aberration) that occurs
(For example, Japanese Patent Application Laid-Open No. 7-21 proposed by the present applicant)
No. 1614). Therefore, the desired tolerance
Test with an electron beam to maintain the
The material surface cannot be scanned indefinitely over a wide area. Follow
Thus, as shown in FIG.
Many fields F restricted to the area_1,F_{2, ....}F _{twenty four}Connect
Create the whole figure pattern by joining. in this case,
Individual field F_1,F_{2, ....}F_{twenty four}Each time you draw a figure
Adjust the center of the sample C so that it matches the optical axis of the scanning electron microscope.
Perform electron beam drawing by moving the stage (necessary in this case
The reproducible moving stage and its driving device
Reference is also made to Japanese Patent Application No. 9-167162 of the present applicant.
Want). The size of the field is 0.1 μm
500 × 500 μm in the typical case^TwoAnd even bigger
If a large aberration is allowed, it can be made even wider. First
A few mm even with the large electron beam lithography system mentioned^TwoDraw the above area
To do this, it is necessary to connect such fields.

The electron beam scanning by the raster system is different from the TV scanning system in which one frame is scanned twice to form one frame, and one field is scanned once to form one field. However, the electron beam is scanned at a constant speed in the horizontal direction, and the deflection operation of the electron beam for sequentially moving the scanning line by a constant width in the vertical direction is regularly performed. The difference between the set position coordinates is very small.

For example, when a high-resolution resist film is printed with an irradiation electron beam having a diameter of 0.1 μm, it takes about 100 to 100 μm to scan a horizontal width of 500 μm as exemplified above.
It takes 300msec. (By the way, it is several tens μs
ec). Therefore, in the raster type electronic writing, if a vertical length of 500 μm is scanned at a resolution of 10,000 lines, it takes about 30 to 90 minutes to complete writing of one field. If the resist material has high sensitivity to electrons, has a coarse pattern and relatively low resolution, it can be processed in a shorter time.

In recent years, graphic patterns created for research use have become extremely fine, that is, the line width and dot size of a pattern to be drawn are on the order of nanometers (several tens of nanometers) smaller than the so-called submicron. ) Pattern is required. In such a situation, the irradiation current value is significantly reduced, so that it is necessary to make the period during which the electron beam stays at each pixel point on the sample surface to be drawn sufficiently long, in other words, it is necessary to lengthen the scanning time . In such a state, the above-mentioned 3
Requires longer drawing time than 0 to 90 minutes. This is because the current of the irradiation beam decreases in proportion to the square of the diameter of the electron beam on the sample surface.

By the way, such a graphic pattern is
As shown in FIG. 2, a limited area of each field F
May appear only in the area. That is, in FIG.
Two very limited areas SQ of field F₁And SQ_TwoOnly exist
Although not shown in detail in these areas,
There is. And these areas SQ₁And SQ_Twoother than
Has no graphic pattern at all. In FIG. 2b, the diameter is
Two relatively large circles C ₁, C_TwoAnd between the two
A thin line LN is arranged. Figure pattern like this
So, as long as you apply normal raster scanning,
Areas without pattern information (white areas in Fig. 2)
When scanning all the figures
We need to be prepared to spend between them.

As is well known, when a drawing figure is created,
Creating a single figure you need is not enough. 100 yields including electron beam drawing work and subsequent work
Since it is not a percentage, it is necessary to prepare several figures of the same pattern in consideration of this yield. Therefore, an extremely long time of electron beam exposure is required to draw a required number of figures. In particular, when connecting a large number of fields, an operation time of about several days is required. In order to perform such a long-time operation, the current intensity of the electron beam, that is, the intensity of the total current emitted from the electron gun, the degree of convergence of the electron beam, and the mechanical stability of the sample stage on which the sample is placed are determined. It must be able to remain constant over time.

[0009] Regions that do not include graphic pattern information are omitted.
A vector method is known as a drawing method for scanning only an area to be drawn. This vector method is, for example, shown in FIG.
As shown in FIG. 3A, a perfect circle is drawn downward and rightward from the point A with a desired line width, or a substantially regular hexagon is drawn as shown in FIG. 3B. Vector-type scanning is widely used in large-sized electron beam lithography systems having an electrostatic electron beam deflection system.
However, when the scanning electron microscope to which the present invention is based is based, the electron beam deflection system uses an electromagnetic deflection coil instead of an electrostatic type, and the electron beam focusing system is a magnetic lens. The use of the vector method has serious drawbacks. In vector-based drawing, if the figure is extremely fine, for example, as shown in Fig. 3a (diameter about 10 µm, line width about 0.3 µm
) And Fig. 3b (Diagonal length about 10 μm, line width about 0.3 μm
In the case of (1), there is no coincidence between the start point A and the end point B, which should be the same in the former case, and in the latter case, irregularities are found that are not constant at the line position where the moving direction of the electron beam changes. For example, cracks occur at corner points like C and D,
A so-called overrun may occur in the drawing line as shown in FIG. Although the cause has not been sufficiently elucidated, it is presumed that the main cause is magnetization hysteresis of the magnetic material of the assembly of the deflection coil of the electron beam deflection system and the magnetic lens surrounding it.

[0010]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a magnetic field type lens and an electromagnetic deflecting device when a figure is relatively simple and there is an area that does not include a figure pattern at all in a part of a field. Electron beam drawing method that can significantly reduce raster-type electron beam drawing time by simple operation using an electron beam drawing apparatus including an electron beam focusing / deflection system comprising a system and an input device for computer-processing graphic data, and An object of the present invention is to provide an electron beam lithography apparatus suitable for carrying out this method.

[0011]

According to the present invention, there is provided an electron beam focusing system for accelerating electrons emitted from an electron beam source, converging the electron beam with a magnetic field type lens to a fine electron beam, and applying the electron beam to a sample. An electromagnetic deflection system that deflects the electron beam in this electron beam focusing system and scans the sample two-dimensionally on the sample surface, and two electrostatic devices that determine whether the electron beam reaches the sample according to the density of the figure Electron beam focusing / conversion consisting of a blanking unit for applying or not applying a DC voltage between the deflecting plate and both deflecting plates
A scanning device 16; a graphic data input operation unit 12 having a CAD function;
A raster image processing unit 10 for forming a scanning signal to an electron beam deflection system and a blanking signal to a blanking unit from the graphic data obtained in step 1 and sending the signal to the electron beam focusing / scanning device 16; In the electron beam drawing method of drawing a figure pattern by electron beam scanning, if the figure pattern to be drawn exists locally in the basic scanning field, the figure data input operation unit 12 obtains the figure pattern data. The scanning start position α and the ending position β of the localized graphic pattern are determined, and the raster image processing unit 10 scans the scanning signal and the blanking signal in the scanning area from the graphic pattern data and the data of the starting position and the ending position. Is formed and sent to the electron beam focusing / scanning device 16 to scan only the desired graphic region with the electron beam. Therefore, it has been solved.

Further, according to the present invention, there is provided an electron beam focusing system for accelerating electrons emitted from an electron beam source, converging the electron beam with a magnetic field type lens to a fine electron beam, and applying the electron beam to a sample. An electromagnetic deflection system that deflects the electron beam in the system and scans the sample two-dimensionally on the sample surface, and two electrostatic deflection plates to determine whether the electron beam reaches the sample according to the density of the figure Electron beam focusing / scanning device 1 comprising a blanking unit for applying or not applying a DC voltage between deflection plates
6 and a graphic data input operation unit 1 having a CAD function
Raster image processing for forming a scanning signal to the electron beam deflecting system and a blanking signal to the blanking unit from the graphic data obtained by the graphic data input operation unit 12 and sending it to the electron beam focusing / scanning device 16 An electron beam drawing apparatus for drawing a figure pattern by scanning a resist film with an electron beam in a raster system, wherein the raster image processing unit 10 comprises a microprocessor μ
P, RAM storage, ROM storage, pattern data storage PDM, control unit SCSI for sending and storing figure pattern data from pattern data input operation unit 12 to pattern data storage PDM, blanking signal sending unit 26, horizontal scanning signal generator, vertical scanning signal generator 30
And the raster image processing unit 10 scans the graphic pattern data obtained by the graphic data input operation unit 12 and scan start position α and scan end position β from the data.
This is solved by having a functional unit that performs signal processing so as to determine a scanning signal and a blanking signal suitable for scanning a desired scanning area.

[0013] Further advantageous configurations according to the invention are set out in the dependent claims.

[0014]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, an electron beam emitted from an electron beam source is accelerated, focused to a fine electron beam by a magnetic lens, and then applied to a sample. An electromagnetic deflection system that deflects the electron beam to scan the sample two-dimensionally on the sample surface, and between the two electrostatic deflection plates and both deflection plates to determine whether the electron beam reaches the sample according to the density of the figure Electron beam focusing / scanning electron microscope consisting of a blanking unit for applying or not applying a DC voltage
It is assumed that a scanning device and a graphic data input operation unit having a CAD function are used.

A scanning signal to the electron beam deflection system and a blanking signal to the blanking unit are formed between the electron beam focusing / scanning device and the graphic data input operation unit from the graphic data obtained by the graphic data input operation unit. A raster image processing unit for feeding the electron beam to the electron beam focusing / scanning device is provided, and the resist film is scanned with an electron beam in a raster system similar to a so-called TV scan to draw a graphic pattern.

According to the electron beam drawing method of the present invention,
When the graphic pattern to be drawn exists locally in the basic scanning field, the graphic data input operation unit obtains the data of the graphic pattern, determines the start position and the end position of the scanning of the localized graphic pattern, and A raster image processing unit forms a scanning signal and a blanking signal in a scanning area from the pattern data and the data of the starting position and the ending position, and sends the scanning signal and the blanking signal to the electron beam focusing / scanning device. I do.

According to the electron beam writing method of the present invention, only the vertical positions of the scanning start position and the ending position of each figure pattern are obtained, and the horizontal scanning of the basic scanning field is performed between the two vertical positions. An electron beam is scanned over the entire width, and drawing is performed without performing horizontal scanning at other vertical positions. According to another advantageous electron beam writing method of the present invention, when a plurality of graphic patterns are scattered in the basic scanning field, the graphic pattern whose scanning start position is the leftmost and the scanning end position is the rightmost. A figure pattern is determined, and horizontal scanning of the electron beam is performed between the leftmost start position and the rightmost end position.

According to the electron beam drawing apparatus of the present invention,
The raster image processing unit is a microprocessor, RA
M storage unit, ROM storage unit, pattern data storage unit, control unit for sending and storing graphic pattern data from the graphic data input operation unit to the pattern data storage unit, blanking signal transmission unit, horizontal scanning signal generation unit , Having a vertical scanning signal generator, and further comprising a raster image processing unit,
A scan start position and an end position are determined from the graphic pattern data obtained by the graphic data input operation unit and the data, and a scan signal and a blanking signal suitable for scanning within a desired scan area are formed. It has a functional unit for signal processing and executes the above-described electron beam drawing method.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail based on embodiments shown in the drawings. FIG. 4 shows functional blocks of the electron beam drawing apparatus according to the present invention. Electron beam focusing / scanning device 16
The operation unit 14 forms an ordinary scanning electron microscope except for a very small special part for electron beam drawing. A raster image processing unit 10 is connected to the scanning electron microscope. Further, the raster image processing unit 10 includes a graphic data input operation unit 12 which includes a personal computer and a monitor and has a CAD function for calculating the two-dimensional position of a graphic to be drawn on the monitor as pattern data. It is connected via the L _10. The raster image processing unit 10 and the graphic data input operation unit 12 constitute a graphic processing device 20 for controlling drawing.
This is called Beam Draw (trademark registration pending by the present applicant). In addition, a stage controller 18 for controlling a sample stage STG for moving a sample (substrate with a resist film) SP is also included. The stage control unit 18 and the mechanism attached thereto are the same as the ultrasonic motor stage drive device (Japanese Patent Application No. 9-167) proposed by the present applicant.
162) may be used, but a detailed description thereof is omitted because it is not directly related to the present invention.

In the electron beam focusing / scanning device 16, the electron gun G
The electrons emitted from the electron beam source are accelerated by the high voltage applied between the beam source and the anode A, and between the electrostatic deflectors E _{1 and} E ₂ provided below the anode A and below the same. It passes through the center hole of a certain aperture plate Ap. Then, the electron beam source image on the surface of the sample SP is reduced focused to a predetermined beam diameter by a focusing lens L _1, L _2. Furthermore, the final to the focusing lens near the optical axis of the L ₂ are for deflecting the electron beam, i.e. XY an electron beam on the sample surface
For scanning in the direction, a pair of deflection coils DF are provided.

Whether the resist film at a specific position on the sample surface is subjected to electron exposure (irradiation with an electron beam) is determined by a deflection voltage applied between the electrostatic deflection plates E ₁ and E ₂ , that is, a blanking voltage. If a blanking voltage is applied, the electron beam deviates from the center hole of the aperture plate Ap and hits the aperture plate Ap, and cannot reach the surface of the sample SP. If no blanking voltage is applied, the electron beam reaches the sample surface. The blanking voltage is supplied from the raster image processing unit 10 according to the pattern signal, and is finally formed by the blanking drive amplifier BLK.

For example, a secondary electron multiplier PMT is also provided as an image detector for monitoring the position of the sample surface and the like. The transmission and reception of signals between the raster image processing unit 10 and the electron beam focusing / scanning device 16 can be understood from the signal conductors in FIG. FIG. 5 shows functional blocks of main circuit elements in the raster image processing unit 10.
The data of the desired graphic pattern supplied from the graphic data input operation unit 12 is SCSI (small computer sys.).
pattern data storage PDM via tem interface)
Is stored in In order to form a desired blanking signal for each scanning position determined by the deflection signal based on the graphic pattern data, an integrated waveform generator 22, a length management unit 24, a blanking signal transmitter 26, a bias horizontal scanning position A generator 28 and a vertical scanning position generator 30 are arranged. These functional elements PDM, 22, 24,
26, 28, and 30 are storage units RO for storing a microprocessor μP, a predetermined arithmetic processing program, required constants, and the like.
M, and a storage RAM for temporarily storing operation processing values
Through a bus 25. Further, the pattern data storage PDM, the integral waveform generator 22, the length management unit 24, and the blanking signal transmitter 26 are connected to each other also via another bus 27 for transmitting and receiving digital signals related to the pattern data of the figure. ing.

The functions of these circuit elements will be described in detail below. It is easy to understand by linking the pattern data stored in the pattern data storage PDM to the basic scanning field. As shown in FIG. 6, a matrix of two-dimensional position P of each pixel in a basic scan field _{(pixels), X i = (i-} 1) X 1, i = 1~M Y i = (j- 1) Assign a blanking value S _BLK to Y _1, j = _{1 to} M. Where M
Is an integer corresponding to the maximum number of pixels in the horizontal and vertical directions of the basic scanning field. The spread of one pixel in the two-dimensional space (resolution in the X and Y directions) is represented by X ₁ and Y ₁ , and the scanning lines in the horizontal direction (X direction) are maximum (= M lines) at Y ₁ intervals in the vertical direction. ) Swept. If it is assumed that the six hatched areas in FIG. 6 are to be exposed, the blanking value S _BLK is L level (no deflection voltage is applied between the electrodes E ₁ and E ₂ ) in these areas. , And H level (a deflection voltage is applied) in the other areas.

As shown in FIG. 8, the integrated waveform generator 22 generates an integrated waveform (sawtooth waveform) signal in which a constant current flowing through the resistor R ₀ is charged by the capacitor C ₀ . This signal is subjected to various processes as will be described later in detail, and is finally supplied as a horizontal scanning signal to the deflection coil DF. The magnitude of the charging current (corresponding to the sweep speed in the X direction) is determined by the bus 25. Is determined by the output voltage specified by the digital-to-analog converter DAC ₁ according to the digital value supplied from the microprocessor μp via the .mu. The magnitude of this current value is determined according to the sensitivity of the resist used and the resolution of drawing, and
It is calculated from predetermined data and a program previously written in the OM. Start and end of the charging of the capacitor C ₀ (discharge) is determined by a switch SW connected in parallel to the capacitor C _0. Receiving a signal representing the completion of the horizontal scanning of the scanning lines, each time the charging of the capacitor C ₀ is started by sending immediately discharge start signal from the microprocessor μP to the control terminal of the switch SW. After the start of the integration, in order to start the integration after the elapse of very short time (0.1 to 1 msec), that is an analog comparator CP ₁ to delay the start of scanning as the offset voltage V _R is provided. This short period corresponds to the sum of the retrace period after the end of scanning and the period during which the transition fluctuation due to the hysteresis of the magnetization generated in the deflection coil immediately after the start of the scanning is settled.
Since the deflection coil has an inductive load and cannot follow the target position during the transition fluctuation, the period is not used.

Analog comparator CP₁Startup output from
Galling signal S₁Is the synchronization unit in the length management unit 24.
Introduced to PLL. This unit PLL has an oscillator O
160 MHz clock pulse supplied by SC
P₀To the variable frequency divider DIV. This variable frequency divider D
IV is designated by microprocessor μP via bus 25
Clock pulse P₀And divide it by
Return frequency pulse P ₁Output as In this case,
Divided pulse P of₁One or an integer multiple of
Conveniently, it corresponds to one pixel of scanning. This pa
Luth P₁Is counted by the counter CNT, X at that time is obtained.
Scan position X_iIs determined. Connect to counter CNT
Digital comparator CP_TwoThen, the count value at that time and the digital
The comparison of the reference values is performed. This digital reference value is
5, a specific horizontal scanning position X set via_i0Phase
Hit. Therefore, the count value of the counter CNT is
When the threshold value is reached, the match signal S_ThreeAnd output
Horizontal scanning ends in microprocessor μP X_i0Reached
And the capacitor C of the integrated waveform generator 22₀Filling
Turn off the electricity. Therefore, from the integral waveform generator 22 to the conductor L₂₀
The analog output signal output to the
The maximum output voltage of the sawtooth waveform is
Specify the length to the scan end position. Length management unit
The counter value accumulated by the counter CNT in
Represents a horizontal scan line starting from the current start position. In addition,
The numerical value is determined by the digital adder AD at the predetermined horizontal scanning
The digital value corresponding to is added, and the added digital
The count value is supplied to the pattern data storage PDM. So
And read the blanking value of PDM from counter CNT
Issue command S_TwoIs also supplied to the pattern data storage PDM.
You. The role of the digital adder AD will be described later in detail.

The blanking signal transmitting section 26 has a parallel input
It is composed of a serial output type shift register REG.
The register REG is to shift operation in accordance with the frequency dividing period of the pulse P ₁ occurring in length management unit 24, corresponding to the horizontal scanning line positions Y _j specified by the microprocessor .mu.P, at the count of the counter CNT A blanking signal value S _BLK of a specified series of horizontal scanning positions X _i is input in parallel to a parallel input terminal of the shift register REG, and is output in series at the cycle of the frequency-divided pulse P ₁ . This output signal is the electrostatic deflection plates E ₁ via the lead L ₂₂ and L ₂ is a pulse _signal,
It is supplied to a driving circuit BLK for E _2.

According to the present invention, as shown in FIG.
Only in the hatched area in the main scan field
These areas are selectively scanned because they have a shape pattern
I do. For example, diagonal point α_1,β₁Within the rectangle specified by
If only area II is scanned, the vertical position of the horizontal scan line
Place Y_B1Is the horizontal scanning position X_A1To X_A3Scan up to the end
X_A3The vertical position Y_B1Move one pixel down
And re-enter horizontal scanning position X_A1To X_A3Scan up to. This
Operation, and finally the vertical position Y_B2Similar horizontal run with
And finish drawing this area II. See Figure 6
Where the pattern to be drawn has three areas II, III, IV
, The scanning of the area II is completed and the diagonal point α
_2,β_TwoScans the rectangular area III specified by
Diagonal point α _3,β_ThreeScan the rectangular area IV specified by
You. In other words, areas II, III, and IV to be selectively drawn are
Can be characterized by the corresponding diagonal points α and β
You. This is a graphic data input operation unit with CAD function.
Can be specified at the time of inputting a figure in step 12. Α, β above
The standard value is Area II: α₁≡ (X_A1,Y_B1), Β₁≡ (X_A3,Y_B2Region III: α_Two≡ (X_A4,Y_B1), Β_Two≡ (X_A2,Y_B2) Region IV: α_Three≡ (X_A5,Y_B3), Β_Three≡ (X_A6,Y_B4) And these coordinate values are in the raster image processing unit 1.
Pattern data storage PDM via SCSI
Or stored in RAM and retrieved and used when needed.
It is.

Another optional scan is by region I. That is, the target graphic pattern is the vertical position of the scanning line between [X _A1, X _A2 ] and the left and right ends of the horizontal scanning position in FIG. 6, [Y _B1, Y _B2 ]; [Y _B3, Y _B4 ] ; . . . . Is localized between In this case, the horizontal scanning interval of the region I is shorter than the horizontal length (Y _M ) of the basic scanning field. Region I
Processing is also the same as described above with respect, to specify the position of the left and right ends [X _A1, X _A2] in graphic data input operation unit 12, and enter the vertical position of the scan lines [Y _B1, Y _B2] or the like, raster The data is stored in the pattern data storage PDM or the RAM via the SCSI in the image processing unit 10.

Still another selective scan is a spot scan of an electron beam.
A horizontal straight line with a width equal to the diameter
Line) needs to be drawn part of the field
You. In that case, individual straight lines are used as parameters α and β.
X coordinate of the beginning and end of _S,X_ENeed to enter
is there. In addition, other optional scans include those shown in FIGS.
For the figure pattern b, the area where the figure pattern exists
Only the entire horizontal width of the basic scanning frame, and
Consider not performing horizontal scanning in areas where there is no
Can be

In the above four examples, if the horizontal scanning of the area not including the graphic pattern is omitted, when the number of scanning lines to be scanned in the horizontal direction is small, the time for drawing one field is significantly reduced. it can. Next, in FIG.
5 and 8 with the help of the diagram of FIG. 7 for an example of selectively scanning only region I (X _A1, X _A2 ) along ₁
The functions of the main circuit elements shown in FIG.

The sawtooth waveform shown in FIG. 7a has a horizontal deflection coil.
5 shows a voltage corresponding to an exciting current applied to the motor. The vertical axis is
, And the horizontal axis indicates the sweep time t.
One-to-one correspondence with the horizontal position x of the basic scanning frame
Have a clerk. That is, t = 0 and V = 0 are the basic frames
At the left end (x = 0 in FIG. 6), and t = t_MAnd V = V _M
Is the right end of the basic frame (x = X_M). to this
Accordingly, the left end (x = X_A1) And the right end (x =
X_A2) Is the saw waveform SAW of FIG._TwoT = t_SAnd t = t_ETo
Each corresponds. Note that the flyback period and the start of scanning
The waiting time considering the transition fluctuation is the actual scanning period
It is not shown in the drawing because it is significantly shorter than the interval.

The analog output generated by the integral waveform generator 22
The force signal is a sawtooth voltage signal SAW_TwoAnd the integration start time is t
_SAnd the integration end time is t_EAnd t_SAnd t_EBetween
Distance, ie (X_A2-X_A1) Is the length management unit 24
Is determined. This saw waveform SAW_TwoThe voltage signal of the conductor L
₂₀To the output end of the bias horizontal scanning position generator 28
The signal is introduced into the analog adding section 29 to be connected. Bias water
In the flat scanning position generator 28, the microprocessor μP
The horizontal position of the left edge of the region I selected by CAD
Α of 6₁That is, X_A1) Depending on x = 0 to x = X_A1Between
Digital displacement voltage V corresponding to the horizontal scanning distance of_SBy
This digital conversion is generated as a horizontal scanning position voltage.
Potential voltage V_SIs built in the bias horizontal scanning position generator 28.
Analog-to-analog converter
Voltage signal V_SOutput as In the analog adder 29
Is the sawtooth waveform voltage signal SAW_TwoThe deflection voltage V_SAdd
And saw waveform SAW₁Is the conductor L₂₈Output to
You. Therefore, the saw waveform SAW ₁The voltage signal of the electron
The line can scan only region I.

The counter CNT of the length management unit 24 determines the horizontal scanning position (start point t _s, end point t _s) of the sawtooth waveform SAW _{2 in} FIG.
_E ) is output, and the digital value of the displacement voltage V _S corresponding to the bias horizontal scanning distance from the origin of the basic scanning frame to the starting point t _s is output to the digital value by the digital adder AD. Is supplied via the bus 25). As a result, summed digital values are output to the bus 27 becomes sawtooth waveform SAW _1, are sent to the shift register REG.
Therefore, with the help of a shift timing signal (a signal obtained by further dividing the frequency-divided pulse P ₁ by the input fraction of the shift register REG) supplied from the counter CNT of the length management unit 24 via the conducting wire S ₂ , the pattern data Memory PDM
Are sequentially read out as data corresponding to the number of parallel input terminals at a horizontal scanning position within a predetermined vertical position.

In conjunction with this, the blanking value of the horizontal scanning range of the pattern data storage device PDM read by the shift register REG is changed from the blanking signal transmitting section 26 to the corresponding blanking signal V _BLK (FIG. 7B). is output on lead L ₂₂ as blanking driving amplifier unit BL
K is introduced. At that time, the vertical position Y ₁ of the scanning line is designated by the vertical scanning position generator 30. The vertical scanning position generator 30 is, like the bias horizontal scanning position generator 28, composed of a digital-to-analog converter and converts a digital vertical scanning position signal introduced via the bus 25 by the microprocessor μP into an analog signal. into an analog vertical scan position signal by a digital converter is supplied to the vertical deflection coil via a line L _26. 1 step movement of the vertical scanning position, indicating that the count value of the coincidence signal (counter CNT output from the digital comparator CP ₂ length management unit 24 via leads S ₃ reaches the end position t _E ), The microprocessor μP receives the completion of the horizontal scanning and generates a vertical movement signal to execute the horizontal scanning. The function of the flip-flop FF in FIG. 8 is merely implicitly shown, and the corresponding function is actually performed by the microprocessor μP.

The horizontal scanning signal shown in FIG. 8 is generated using an analog integration signal for charging a capacitor. This signal is generated by digital processing and finally converted into an analog value by a digital / analog converter. There is also a way to do this. FIG. 9 shows a circuit arrangement for realizing this method.
In this case, the integrated waveform generator 22 and the analog adder 29 of FIG. 5 are no longer used. The length management unit 24 is shown in FIG.
The configuration is almost the same as that of the above. Just as the points of difference operation start signals S ₁ synchronous unit PLL is mentioned flip-flop FF (previously illustrated schematically, this function rather than being implemented as individual devices, executed by a microprocessor μP Is supplied from
Operation start signals S ₁ to the output terminal Q and put a start signal of the scanning start the set input is generated and supplied to the connected synchronization unit PLL between the oscillator OSC and the variable frequency divider DIV. Thus, the high-frequency pulse P ₀ of the oscillator OSC
The dividing pulses P _1, which is divided is output. This pulse P
₁ corresponds to the horizontal scanning position, the pulse counted to introduce the count value to a comparator CP ₂ which compares the digital reference position value corresponding to a predetermined horizontal scanning distance. Movement of the biasing horizontal scanning position shown in FIG. 7, i.e. operation of adding the voltage V _S to the deflection voltage is performed by the digital adder AD as already described. This digital sum is used as the digital / analog converter DAC ₂ of the horizontal scanning signal generator 28 '.
Is converted into an analog value on the basis of a control signal of the microprocessor μP supplied from the bus 25 at medium, is output on lead L _28, supplied to the horizontal deflection coil.

A blanking signal transmitting section 26 incorporating other functions of the length management unit 24 and the shift register REG
And function of the horizontal scanning position generator 30 with a built-in digital-to-analog converter DAC _3, so is as already described, omitting the description of it, or the like. Various changes and improvements can be considered for the specific example of the circuit configuration described above. However, it goes without saying that all the methods and apparatuses having the structures defined in the claims fall within the scope of the present invention.

[0037]

As described above, the electron beam drawing method of the present invention and the electron beam drawing apparatus suitable for carrying out the method make it possible to form a figure relatively simple and to form a figure pattern on a part of a field. When there is an area that does not include the area at all, the raster-type electron beam writing time can be significantly reduced by a simple operation.

[Brief description of the drawings]

FIG. 1 is a plan view showing a field arrangement on a sample substrate,

FIG. 2 is a plan view showing an example of a field in which a graphic pattern is localized, (a) a pattern having two discrete areas, (b) a single pattern,

FIG. 3 shows examples of irregularities occurring in a typical graphic pattern drawn by vector-based scanning, (a) a circle, (b) a hexagon,

FIG. 4 is a functional block diagram of the entire electron beam drawing apparatus;

FIG. 5 is a functional block diagram of main processing circuit elements in the raster image processing unit,

FIG. 6 is a plan view showing an arrangement in a frame when a graphic pattern to be drawn is localized;

FIG. 7 is a waveform diagram (b) of a blanking signal corresponding to a voltage (a) for determining a horizontal sweep position during selective scanning,

FIG. 8 is a detailed circuit diagram of one specific example of an integrated waveform generator, a length management unit, and a blanking signal transmission unit in the raster image processing unit;

FIG. 9 is a detailed circuit diagram of another specific example of the integrated waveform generator, the length management unit, and the blanking signal transmission unit in the raster image processing unit.

[Explanation of symbols]

Reference Signs List 10 Raster image processing unit 12 Graphic data input operation unit 14 Operation unit of electron beam focusing / scanning device 16 Electron beam focusing / scanning device 18 Stage control unit 20 Graphic processing device 22 Integral waveform generation unit 24 Length management unit 25 Bus 26 B Ranking signal sending unit 27 Other bus 28 Bias horizontal scanning position generating unit 28 'Horizontal scanning position generating unit 30 Vertical scanning position generating unit PDM pattern data storage μP Microprocessor BLK Blanking drive amplifying unit I, II, III, IV selection Scanning area X Horizontal scanning position in basic scanning field Y Vertical position of scanning line in basic scanning field α, β Start and end points of selected area

Claims (4)

[Claims] Claims: 1. Accelerate electrons emitted from an electron beam source,
An electron beam focusing system that focuses a fine electron beam with a magnetic field lens and hits the sample, an electromagnetic deflection system that deflects the electron beam within this electron beam focusing system and performs two-dimensional scanning on the sample surface, and An electron beam focusing and scanning device (16) comprising two electrostatic deflectors and a blanking unit for applying or not applying a DC voltage between the two deflectors in order to determine whether the electron beam reaches the sample or not; A graphic data input operation unit (12) having a CAD function, and a scanning signal to an electron beam deflection system and a blanking signal to a blanking unit are formed from the graphic data obtained by the graphic data input operation unit (12). , The electron beam focusing and scanning device (1)
6) a raster image processing unit (10) for sending to
In an electron beam drawing method for drawing a figure pattern by scanning a resist film with an electron beam in a raster system, when a figure pattern to be drawn exists locally in a basic scanning field, a figure data input operation unit (1
The data of the graphic pattern is obtained by 2), the start position (α) and the end position (β) of the scanning of the localized graphic pattern are determined, and the raster image processing is performed from the graphic pattern data and the data of the start position and the end position. A unit (10) forms a scanning signal and a blanking signal in a scanning area, sends the signal to the electron beam focusing / scanning device (16), and performs electron beam scanning only on a desired figure area. Method. 2. The method according to claim 1, wherein only the vertical position of the starting position and the ending position of the scanning of each graphic pattern is determined, and the electron beam is scanned between the two vertical positions over the entire width of the horizontal scanning of the basic scanning field. 2. The electron beam drawing method according to claim 1, wherein drawing is performed without performing horizontal scanning of the position. 3. When a plurality of graphic patterns are scattered in the basic scanning field, a graphic pattern whose scanning start position is the leftmost and a graphic pattern whose scanning end position is the rightmost are determined. 3. The electron beam drawing method according to claim 2, wherein horizontal scanning of the electron beam is performed between the start position and the rightmost end position. 4. Accelerating electrons emitted from an electron beam source,
An electron beam focusing system that focuses a fine electron beam with a magnetic field lens and hits the sample, an electromagnetic deflection system that deflects the electron beam within this electron beam focusing system and performs two-dimensional scanning on the sample surface, and An electron beam focusing and scanning device (16) comprising two electrostatic deflectors and a blanking unit for applying or not applying a DC voltage between the two deflectors in order to determine whether the electron beam reaches the sample or not; A graphic data input operation unit (12) having a CAD function, and a scanning signal to an electron beam deflection system and a blanking signal to a blanking unit are formed from the graphic data obtained by the graphic data input operation unit (12). , The electron beam focusing and scanning device (1)
6) a raster image processing unit (10) for sending to
In an electron beam drawing apparatus for drawing a figure pattern by scanning a resist film with an electron beam in a raster system, a raster image processing unit (10) includes a microprocessor (μP), a RAM storage, a ROM storage, and a pattern data storage (PDM). ), A control unit (SCS) for sending and storing graphic pattern data from the graphic data input operation unit (12) to a pattern data storage (PDM).
I), a blanking signal transmitting section (26), a horizontal scanning signal generating section, a vertical scanning signal generating section (30), and a raster image processing unit (10) is obtained by a graphic data input operation unit (12). Starting position (α) and ending position (β) of scanning from the figure pattern data
An electron beam lithography apparatus having a function unit that determines a scan signal and performs signal processing so as to form a scanning signal and a blanking signal suitable for scanning in a desired scanning area.