JP2012160346A - Deflection amplifier evaluation method and charged particle beam lithography method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of evaluating the stability of a main deflection amplifier accurately, and to provide a charged particle beam lithography method ensuring high precision drawing by evaluating the stability of a main deflection amplifier accurately.SOLUTION: A predetermined position of a main deflection region 200 determined by the deflection width of a main deflector is irradiated with an electron beam. After a predetermined time, for an evaluation mark 100 composed of a material having a reflectance different from that of a foundation material composing the main deflection region 200, a position taking on both the foundation and the evaluation mark 100 is irradiated with an electron beam. Reflection electrons are detected as a current value, and a main deflection amplifier is evaluated based on the variation of the current value.

Description

  The present invention relates to a deflection amplifier evaluation method and a charged particle beam writing method.

  In recent years, the circuit line width required for a semiconductor element has become increasingly narrower as the large scale integrated circuit (LSI) is highly integrated and has a large capacity. The semiconductor element uses an original pattern pattern (a mask or a reticle, which will be collectively referred to as a mask hereinafter) on which a circuit pattern is formed, and the circuit is exposed and transferred onto a wafer by a reduction projection exposure apparatus called a stepper. Manufactured by forming. For manufacturing a mask for transferring such a fine circuit pattern onto a wafer, an electron beam drawing apparatus capable of drawing the fine pattern is used. Attempts have also been made to develop a laser beam drawing apparatus for drawing using a laser beam. The electron beam drawing apparatus is also used when drawing a pattern circuit directly on a wafer.

  Patent Document 1 discloses an example of a variable shaping type electron beam drawing apparatus. In this apparatus, a stage on which a mask is placed is housed inside a sample chamber, and an electron beam optical system is provided above the sample chamber. The electron beam optical system includes an electron gun, various lenses, a deflector for blanking, a deflector for variable beam size, a main deflector and a sub deflector for beam scanning, and two beam shaping apertures. .

  The electron beam emitted from the electron gun is turned on and off by the blanking deflector.

  The size and shape of the electron beam are controlled by a beam size variable deflector and a beam shaping aperture. Specifically, the electron beam is shaped into a rectangular shape by the first shaping aperture and then deflected onto the second shaping aperture by the deflector to change the beam shape and dimensions.

  Further, the irradiation position of the electron beam is positioned in a predetermined subfield by the main deflector, and positioning in the subfield is performed by the subdeflector. Then, the stage is continuously moved in one direction to perform drawing in the subfield. When drawing of one subfield is completed, the drawing moves to the next subfield.

JP-A-10-284392

  Specifically, the deflection control of the electron beam is performed by the above-described deflector and deflection amplifier. Similar to the deflector, a plurality of deflection amplifiers are provided depending on the type of deflection. In order to deflect the electron beam to a desired position, the stability of the output voltage of the deflection amplifier is indispensable.

  There are two methods for evaluating the main deflection amplifier in the conventional method: mounting the main deflection amplifier on an actual machine and evaluating the drawing result; and evaluating the output waveform with an oscilloscope by applying a load equivalent to the actual machine to the main deflection amplifier alone. There is.

  According to the former method, that is, the method based on the actual drawing result, the stability of the main deflection amplifier can be most reliably evaluated. However, in this case, it takes several hours to several tens of hours of drawing time for one evaluation of drawing, process, and analysis, and an expensive evaluation mask is required. Therefore, the latter method, that is, a method of evaluating the main deflection amplifier by monitoring an output signal from the main deflection amplifier to the main deflector with an oscilloscope.

  Incidentally, electron beam shots are output at high speed and continuously. Therefore, in order to evaluate the main deflection amplifier that controls such a beam shot, a highly accurate measuring instrument is required. However, the measurement using an oscilloscope has a problem that the oscilloscope input circuit is saturated and an accurate waveform cannot be observed. In addition, this method also has a problem that a downtime of the apparatus of about several hours occurs due to the connection of the oscilloscope. Furthermore, the evaluation result by the oscilloscope may not match the evaluation result by drawing. This is presumed that the evaluation with the main deflection amplifier alone cannot be performed in a state using an electron beam.

  The present invention has been made in view of these problems. That is, an object of the present invention is to provide a method capable of accurately evaluating the stability of a main deflection amplifier. Another object of the present invention is to provide a charged particle beam writing method capable of writing with high accuracy by accurately evaluating the stability of a main deflection amplifier.

  Other objects and advantages of the present invention will become apparent from the following description.

A first aspect of the present invention is a charged particle beam drawing apparatus that draws a predetermined pattern by deflecting a charged particle beam using a main deflector and a sub deflector arranged on an optical path of the charged particle beam. An evaluation method of a deflection amplifier used for
A charged particle beam is irradiated to a predetermined position of the main deflection area determined by the deflection width of the main deflector, and after a predetermined time, a mark made of a material having a reflectance different from that of the base material constituting the main deflection area It is characterized in that a charged particle beam is irradiated to both positions of the mark to detect reflected charged particles as a current value, and the deflection amplifier is evaluated based on the fluctuation amount of the current value.

In the first aspect of the present invention, it is preferable to detect the reflected charged particles as a current value by changing a distance from a predetermined position of the main deflection region to a position on both the base and the mark.
Thereby, an appropriate settling time according to the distance can be obtained. Further, since the measurement time is shorter than the method of detecting the current value of the charged particle beam by the Faraday cup, it does not take a long time for the whole measurement even if the measurement is performed at different distances.

In the first aspect of the present invention, it is preferable to detect the reflected charged particles as a current value by changing the predetermined time.
Thereby, an appropriate settling time can be obtained. In addition, since the measurement time is shorter than the method of detecting the current value of the charged particle beam by the Faraday cup, even if the measurement is performed for a predetermined time, that is, by changing the settling time, the entire measurement does not require a long time.

A second aspect of the present invention is a charged particle beam that deflects a charged particle beam using a main deflector and a sub deflector disposed on an optical path of the charged particle beam and draws a predetermined pattern on a sample on the stage. A drawing method,
A charged particle beam is irradiated to a predetermined position of the main deflection area determined by the deflection width of the main deflector, and after a predetermined time, a mark made of a material having a reflectance different from that of the base material constituting the main deflection area A feature is that a charged particle beam is irradiated to a position on both of the marks to detect reflected charged particles as a current value, and a predetermined pattern is drawn after a fluctuation amount of the current value becomes constant.

In the second aspect of the present invention, the distance from the predetermined position of the main deflection region to the position of both the ground and the mark is changed, the reflected charged particles are detected as the current value, and the settling time is determined from the current value. It is preferable to do.
Since the measurement time is shorter than the method of detecting the current value of the charged particle beam with the Faraday cup, the entire measurement does not take a long time even if the measurement is performed at different distances, and an appropriate settling time is determined. be able to.

  According to the present invention, there is provided a method capable of accurately evaluating the stability of the main deflection amplifier. Further, according to the present invention, since the stability of the main deflection amplifier can be accurately evaluated, a charged particle beam writing method capable of writing with high accuracy is provided.

It is a block diagram of the electron beam drawing apparatus in this Embodiment. It is explanatory drawing of the drawing method by the electron beam of this Embodiment. It is an example which shows the relationship between the mark for evaluation and the main deflection area in the present embodiment. It is an example of the evaluation method of the main deflection amplifier in this Embodiment. It is a figure which shows the shaping | molding deflector which consists of an 8-electrode electrostatic deflector, and the DAC amplifier unit which applies analog data to each electrode. It is another example of the evaluation method of the main deflection amplifier in this Embodiment. It is a figure which shows the positional relationship of the three electron beam shots in FIG.

  FIG. 1 is a configuration diagram of an electron beam drawing apparatus according to the present embodiment.

  As shown in FIG. 1, the electron beam drawing apparatus includes a drawing unit that draws an electron beam on a sample and a control unit that controls drawing.

  In the sample chamber 1, a stage 3 on which the sample 2 is installed is provided. The stage 3 is driven by the stage drive circuit 4 in the X direction (left and right direction on the paper surface) and the Y direction (vertical direction on the paper surface). The moving position of the stage 3 is measured by a position circuit 5 using a laser interferometer or the like.

  An electron beam optical system 10 is installed above the sample chamber 1. The optical system 10 includes an electron gun 6, various lenses 7, 8, 9, 11, 12, a blanking deflector 13, a shaping deflector 14, a beam scanning main deflector 15, and a beam scanning sub deflector. 16 and two beam shaping apertures 17, 18 and the like.

  FIG. 2 is an explanatory diagram of a drawing method using an electron beam. As shown in this figure, the pattern 51 drawn on the sample 2 is divided into strip-shaped frame regions (also referred to as main deflection regions in the present specification; the same applies hereinafter) 52. Drawing with the electron beam 54 is performed for each frame region 52 while the stage 3 continuously moves in one direction (for example, the X direction). The frame area 52 is further divided into sub-fields (sub-deflection areas) 53, and the electron beam 54 draws only necessary portions in the sub-field 53. The frame area 52 is a strip-shaped drawing area determined by the deflection width of the main deflector 15, and the subfield 53 is a unit drawing area determined by the deflection width of the sub-deflector 16.

  The positioning of the reference position of the subfield is performed by the main deflector 15, and the drawing in the subfield 53 is controlled by the subdeflector 16. That is, the main deflector 15 positions the electron beam 54 in a predetermined subfield 53, and the subdeflector 16 determines the drawing position in the subfield 53.

  The shape and size of the electron beam 54 are determined by the shaping deflector 14 and the beam shaping apertures 17 and 18.

  Then, the inside of the subfield 53 is drawn while continuously moving the stage 3 in one direction, and when drawing of one subfield 53 is completed, the next subfield 53 is drawn. When drawing of all the subfields 53 in the frame area 52 is completed, the stage 3 is step-moved in a direction (for example, Y direction) orthogonal to the direction in which the stage 3 is continuously moved. Thereafter, the same processing is repeated, and the frame area 52 is sequentially drawn.

  The sample 2 is provided with an evaluation mark for evaluating the stability of the main deflection amplifier. This evaluation mark is formed of a material having a reflectance different from that of the sample surface. In the present embodiment, an evaluation mark may be provided as close as possible to the sample surface, not the sample surface.

  For example, the evaluation mark may be formed in a lattice shape by providing a tungsten film on a silicon substrate and etching the tungsten film. Instead of the tungsten film, a film made of another heavy metal can be used. The combination of the evaluation mark and its base is preferably as the difference in reflectance between the two is large and the value of one of the reflectances is small. This makes it easy to grasp the degree of stability of the deflection amplifier described later.

  The relationship between the evaluation mark 100 and the main deflection area 200 is as shown in FIG. As can be seen from this figure, the outer periphery of one main deflection region 200 is located inside the range surrounded by the evaluation mark 100. In this example, it is assumed that the evaluation mark 100 is made of a tungsten film formed on a base made of a silicon substrate.

A method for evaluating the main deflection amplifier according to the present embodiment will be described with reference to FIG. FIG. 4 is an enlarged view of the vicinity of the boundary between the evaluation mark and the main deflection area shown in FIG. In the main deflection amplifier evaluation method of this embodiment, first, an arbitrary beam (x ₁ , y ₁ ) is irradiated with an electron beam. That is, a voltage is applied to the main deflection amplifier so that the electron beam is irradiated to the coordinates (x ₁ , y ₁ ). Reference numeral 301 in the figure represents a shot of the electron beam irradiated on the coordinates. In this example, the electron beam is shaped into a square shape.

Next, after a predetermined settling time, a voltage is applied to the main deflection amplifier to deflect the electron beam to the coordinates (x ₁ , y ₂ ). At this time, the coordinates (x ₁ , y ₂ ) are set so that a part of the shot of the electron beam is on the evaluation mark.

If the output voltage of the main deflection amplifier is not stable, the electron beam cannot be deflected to a desired position. That is, even if the electron beam irradiation position is moved from the coordinates (x ₁ , y ₁ ) to the coordinates (x ₁ , y ₂ ), the electron beam is not stable when the output voltage of the main deflection amplifier is not stable. , A position shifted from the coordinates (x ₁ , y ₂ ) is irradiated. Code 303 of figure coordinates _(x 1, _{y 2)} represents the electron beam shot just after the electron beam is deflected, the shot position shifted from the coordinates _(x 1, _{y 2)} (coordinates ( x ₁ , y ₃ )).

Thereafter, the irradiation position changes as indicated by a dotted rectangle until the output voltage is stabilized, and after the output voltage is stabilized, the irradiation position is fixed to the coordinates (x ₁ , y ₂ ). Reference numeral 302 in the figure represents a shot of the electron beam irradiated on this coordinate. The irradiation position varies in the direction of the arrow (+ Y direction) in the example of FIG. 4, but may also vary in the −Y direction. Which direction varies depends on the characteristics of the main deflection amplifier. .

  By the way, when the sample 2 is irradiated with the electron beam, the sample 2 reflects the electrons and generates reflected electrons. Here, the amount of reflected electrons generated when the tungsten film is irradiated with the electron beam is different from the amount of reflected electrons generated when the silicon substrate is irradiated with the electron beam. Specifically, the former is more than the latter.

In the example of FIG. 4, the irradiation position of the electron beam varies until the output voltage of the main deflection amplifier is stabilized. With this change, the area of the tungsten film and the area of the silicon substrate in the electron beam irradiation region change relatively. In FIG. 4, the shot is first shot at the coordinates (x ₁ , y ₃ ), and then moved in the + Y direction and then fixed at the coordinates (x ₁ , y ₂ ). Therefore, the area of the tungsten film in the electron beam irradiation region is gradually reduced, and the area of the silicon substrate is gradually increased instead.

  The amount of reflected electrons generated by irradiating the tungsten film with the electron beam is different from the amount of reflected electrons generated by irradiating the electron beam on the silicon substrate. The change in the relative area between the tungsten film and the silicon substrate can be known. When the amount of reflected electrons is constant, it can be seen that the irradiation position of the electron beam is fixed and the output voltage of the main deflection amplifier is constant.

  The amount of reflected electrons can be measured as a current value. In the example of FIG. 4, as a result of the amount of reflected electrons gradually decreasing, the measured current value also gradually decreases. After the output voltage of the deflection amplifier is stabilized, the measured current value is also constant. When the electron beam moves in the −Y direction from the initial irradiation position, the area of the tungsten film gradually increases with this movement. As a result, the amount of reflected electrons gradually increases, and the measured current value also gradually increases.

  In FIG. 1, when the sample 2 is irradiated with an electron beam, the sample 2 reflects the electrons and generates reflected electrons. Above the sample chamber 1, a detector 32 is provided that detects reflected electrons generated as a result of irradiation of the evaluation mark with an electron beam as a current value. The detector 32 may detect secondary electrons as current values in addition to the reflected electrons.

  The electrical signal output from the detector 32 is input to the detection unit 33. Then, after being amplified by the detection unit 33, it is input to the A / D conversion unit 34. The A / D converter 34 converts the analog signal from the detector 33 into a digital signal. The converted digital signal is sent to the control computer 19. Here, since the A / D converter 34 can accumulate the data from the detector 33, it is not necessary to transfer the data to the control computer 19 for each measurement. Therefore, the lengthening of the sampling time due to the communication time can be reduced.

  From the data sent to the control computer 19, the time until the fluctuation of the current value is saturated is obtained in the control computer 19. At this time, for example, exponential function fitting is used to interpolate the measurement values. The performance of the main deflection amplifier can be evaluated from the obtained saturation time. Such an evaluation can be performed before starting the electron beam drawing apparatus or during periodic inspection.

  By the way, the amount of current of the electron beam can also be detected by a Faraday cup. However, while the output voltage of the main deflection amplifier stabilizes in a time of about 1 millisecond, for example, the Faraday cup can detect a fluctuation only at a period of about 10 Hz, that is, at a time interval of about 100 milliseconds. On the other hand, according to the method of this embodiment, it is possible to detect the fluctuation amount of the irradiation position at a period of 1 MHz, that is, at a time interval of about 1 microsecond.

  According to the present embodiment, an appropriate settling time in the actual drawing process can be easily grasped. This point will be described in detail below.

  When the deflector is driven by the deflection amplifier, an output voltage settling time (settling time) corresponding to the load is required. In other words, a predetermined settling time is required to set the target deflection position. On the other hand, the moving distance of the electron beam in the actual drawing process, that is, the deflection amount of the main deflection amplifier is not constant, and takes various values depending on the arrangement of the drawn pattern. Therefore, by grasping the relationship between the moving distance of the electron beam and the settling time, it is possible to set an appropriate settling time according to the moving distance.

Here, according to the present embodiment, since the measurement time is short, it is possible to know the variation amount of the irradiation position in a plurality of settling times by one measurement without performing the measurement every settling time. . For example, in FIG. 4, by changing the coordinates _(x 1, _{y 1)} moving distance from the coordinates _{(x 1, y 2) (} y 1 -y 2), to observe the variation in the irradiation position of the electron beam. Specifically, the current value of the electron beam is measured. Since the time until the current value does not change is the optimum settling time, the optimum settling time corresponding to the moving distance can be obtained by performing the above measurement.

In the above description, the example in which the electron beam is moved from the coordinates (x ₁ , y ₁ ) to the coordinates (x ₁ , y ₂ ) has been described. However, the coordinates (x ₁ , y ₁ ) are changed to the coordinates (x ₂ , y ₁ ). It may be moved. In this case, the electron beam moves in the + X direction or the −X direction until the output voltage of the main deflection amplifier is stabilized according to the characteristics of the main deflection amplifier.

  However, in the electron beam drawing apparatus, the electron beam may not be deflected to a desired position due to a failure of the main deflector. Hereinafter, an evaluation method of the main deflection amplifier in this case will be described.

  The main deflector is constituted by a plurality of electrodes such as 4 poles or 8 poles. Each electrode is connected to at least one DAC (digital / analog converter) amplifier unit (main deflection amplifier), and the deflection control unit synchronizes a plurality of digital data for controlling the main deflector with the DAC amplifier unit. Send while taking. The digital data is an instruction voltage signal (digital signal) to a plurality of electrodes constituting the main deflector. Each DAC amplifier unit provided corresponding to each electrode DA converts the digital data received from the deflection control unit, amplifies the analog data after the DA conversion, and further applies the amplified analog data to the corresponding electrode. Send.

  FIG. 5 is a diagram showing eight electrodes 130a to 130h and eight DAC amplifier units 232 that apply analog data to each electrode. The eight electrodes 130a to 130h are composed of four pairs of electrodes facing each other, and analog voltages are applied from the corresponding DAC amplifier units 232a to 232h, respectively.

In FIG. 5, the voltage “y” is applied to the electrode 130a from the DAC amplifier unit 232a, and the voltage “−y” is applied to the electrode 130e that is the counter electrode of the electrode 130a from the DAC amplifier unit 232e. Further, the voltage “(x + y) / 2 ^1/2 ” is applied to the electrode 130b from the DAC amplifier unit 232b, and the voltage “(−x−y” is applied to the electrode 130f that is the counter electrode of the electrode 130b from the DAC amplifier unit 232f. ) / 2 ^1/2 "is applied. Further, the voltage “x” is applied to the electrode 130c from the DAC amplifier unit 232c, and the voltage “−x” is applied to the electrode 130g which is the counter electrode of the electrode 130c from the DAC amplifier unit 232g. Further, the voltage “(xy) / 2 ^1/2 ” is applied to the electrode 130d from the DAC amplifier unit 232d, and the voltage “(−x + y) is applied to the electrode 130h that is the counter electrode of the electrode 130d. ) / 2 ^1/2 "is applied.

  When the digital data for controlling each electrode 130a to 130h of the main deflector 130 is transmitted from the deflection control unit 230 to each DAC amplifier unit 232a to 232h, each electrode 130a to 130h is transmitted from each DAC amplifier unit 232a to 232h. In addition, an analog voltage is applied.

  Although FIG. 5 shows the main deflector 130 composed of four pairs (eight) electrodes, the main deflector 130 may be composed of two pairs (four) electrodes.

With respect to the main deflector 130 of FIG. 5, when the above voltage is applied to each of the eight-pole electrostatic deflectors, the position fluctuation of the electron beam is proportional to the applied voltage. It is represented by In the following formula, α is the deflection sensitivity.

For example, it is assumed that the electrode 130c in FIG. 5 is fixed at 0V due to a failure of the main deflection amplifier. In this case, the position X and the position Y are respectively expressed by the following equations.

  Thus, the position X when the main deflection amplifier is normal is 4αx, whereas when the electrode 130c is fixed at 0V, the position x becomes 3αx. That is, the electron beam can be deflected only by about (3/4) of a desired deflection amount.

  Therefore, an evaluation method of the main deflection amplifier in such a case will be described with reference to FIGS.

In FIG. 6, first, an electron beam is irradiated to the position of coordinates (x ₁ , y ₁ ). Specifically, a voltage is applied to the main deflection amplifier so that the electron beam is irradiated to the coordinates (x ₁ , y ₁ ).

Next, after a predetermined settling time, a voltage is applied to the main deflection amplifier to deflect the electron beam to the coordinates (x ₁ , y ₂ ). At this time, the coordinates (x ₁ , y ₂ ) are set so that a part of the shot of the electron beam is on the evaluation mark.

If the output voltage of the main deflection amplifier is not stable, the electron beam cannot be deflected to a desired position. That is, even if the electron beam irradiation position is moved from the coordinates (x ₁ , y ₁ ) to the coordinates (x ₁ , y ₂ ), the electron beam is not stable when the output voltage of the main deflection amplifier is not stable. , A position shifted from the coordinates (x ₁ , y ₂ ) is irradiated. Thereafter, the irradiation position fluctuates until the output voltage is stabilized, and the fluctuation is stopped after the output voltage is stabilized.

In the example of FIG. 6, when a voltage is applied to the main deflection amplifier in an attempt to move from the coordinates (x ₁ , y ₁ ) to the coordinates (x ₁ , y ₂ ), until the output voltage of the deflection amplifier is stabilized, Although the irradiation position was varied in the + Y direction, after the output voltage was stabilized, it was fixed at the target coordinates (x ₁ , y ₂ ).

However, in the example of FIG. 6, the irradiation position is changed not only in the + Y direction but also in the −X direction as indicated by a dotted rectangle and an arrow. The coordinates finally fixed are (x ₂ , y ₃ ). This indicates that a failure has occurred in the main deflection amplifier as described with reference to FIG. 5, and the deflection cannot be performed with a desired deflection amount.

の方向へ曲げられる。この曲げられた電子ビームの傾きに、ステージ面までの距離を乗ずると、電子ビームの照射位置の変動量が分かる。 For example, assume that the electrode 130c is defective in FIG. Assuming that the voltage error amount at this time is δV, the electron beam is bent by the force of eδE (x, y) by the electric field δE (x, y) created in the space by δV. Here, assuming that the direction of δE (x, y) is electrode 130c-electrode 130g, the electron beam is

It is bent in the direction of By multiplying the angle of the bent electron beam by the distance to the stage surface, the amount of fluctuation of the irradiation position of the electron beam can be found.

On the other hand, when the actual deflection position is (x ₂ , y ₃ ) with respect to the target coordinate (x ₁ , y ₂ ), the change amount of these coordinate positions is represented by the change amount of the position vector. The This will be described with reference to FIG. In FIG. 7, a vector A represents the amount of change from the initial position (x ₁ , y ₁ ) to the target position (x ₁ , y ₂ ). On the other hand, the vector B represents the amount of change from the initial position (x ₁ , y ₁ ) to the actual irradiation position (x ₂ , y ₃ ). Therefore, by comparing the vector A and the vector B, the target deflection amount and the actual deflection amount can be compared.

  In the present embodiment, the amount of reflected electrons generated by being reflected by the sample 2 is measured as a current value, whereby the amount of variation in the irradiation position of the electron beam can be obtained. This fluctuation amount corresponds to the difference between the vector A and the vector B. Therefore, it is possible to identify the electrode that has caused the failure using the above relationship from this value.

  Next, the control unit in the electron beam drawing apparatus of FIG. 1 will be described in detail.

  In FIG. 1, reference numeral 20 denotes an input unit, which is a part where drawing data of the sample 2 is input to the electron beam drawing apparatus through a magnetic disk as a storage medium. The drawing data read from the input unit 20 is temporarily stored in the pattern memory 21 for each frame area (main deflection area) 52 that can be deflected by the main deflector 15. The pattern data for each frame area 52 stored in the pattern memory 21, that is, the frame information composed of the drawing position, the drawing graphic data, etc. is corrected by the drawing data correction unit 31 and then the pattern data which is the data analysis unit The data is sent to the decoder 22 and the drawing data decoder 23.

  The drawing data correction unit 31 performs drift correction on the original design value data. Specifically, a correction value for drift correction is calculated based on data input from the A / D conversion unit 34 to the control computer 19. Then, the design value data and the correction value data are added and synthesized.

  The drawing data correction unit 31 further performs position correction on the stage 3 with respect to the design value data subjected to drift correction. That is, the position data of the stage 3 measured by the position circuit 5 is sent to the drawing data correction unit 31 and added to the data of the design value subjected to drift correction. The synthesized data is sent to the pattern data decoder 22 and the drawing data decoder 23.

  Information from the pattern data decoder 22 is sent to a blanking circuit 24 and a beam shaper driver 25. Specifically, blanking data based on the data is created by the pattern data decoder 22 and sent to the blanking circuit 24. Desired beam size data is also created and sent to the beam shaper driver 25. Then, a predetermined deflection signal is applied from the beam shaper driver 25 to the shaping deflector 14 of the electron optical system 10 to control the size of the electron beam 54.

  The deflection control unit 30 in FIG. 1 is connected to a settling time determination unit 29, the settling time determination unit 29 is connected to a subfield deflection amount calculation unit 28, and the subfield deflection amount calculation unit 28 is connected to the pattern data decoder 22. Connected. The deflection control unit 30 is connected to a blanking circuit 24, a beam shaper driver 25, a main deflector driver 26, and a sub deflector driver 27.

  The output of the drawing data decoder 23 is sent to the main deflector driver 26 and the sub deflector driver 27. Then, a predetermined deflection signal is applied from the main deflector driver 26 to the main deflector 15 of the electron optical system 10, and the electron beam 54 is deflected and scanned to a predetermined main deflection position. In addition, a predetermined sub deflection signal is applied from the sub deflector driver 27 to the sub deflector 16, and drawing in the sub field 53 is performed.

  Next, a drawing method by the electron beam drawing apparatus will be described.

  First, the sample 2 is placed on the stage 3 in the sample chamber 1. Next, the position of the stage 3 is detected by the position circuit 5, and the stage 3 is moved to a position where drawing can be performed by the stage drive circuit 4 based on a signal from the control computer 19.

  Next, an electron beam 54 is emitted from the electron gun 6. The emitted electron beam 54 is collected by the illumination lens 7. Then, the blanking deflector 13 performs an operation for irradiating the sample 2 with the electron beam 54.

  The electron beam 54 incident on the first aperture 17 passes through the opening of the first aperture 17 and is then deflected by the shaping deflector 14 controlled by the beam shaper driver 25. And it passes through the opening part provided in the 2nd aperture 18, and becomes a beam shape which has a desired shape and a dimension. This beam shape is a drawing unit of the electron beam 54 applied to the sample 2.

  The electron beam 54 is shaped into a beam shape and then reduced by the reduction lens 11. The irradiation position of the electron beam 54 on the sample 2 is controlled by the main deflector 15 controlled by the main deflector driver 26 and the sub deflector 16 controlled by the sub deflector driver 27. The main deflector 15 positions the electron beam 54 in the subfield 53 on the sample 2. The sub deflector 16 positions the drawing position within the subfield 53.

  Drawing with the electron beam 54 on the sample 2 is performed by scanning the electron beam 54 while moving the stage 3 in one direction. Specifically, a pattern is drawn in each subfield 53 while moving the stage 3 in one direction. After all the subfields 53 in one frame area 52 have been drawn, the stage 3 is moved to a new frame area 52 and drawn similarly.

  After drawing all the frame regions 52 of the sample 2 as described above, the mask is replaced with a new mask, and drawing by the same method as above is repeated.

  Next, drawing control by the control computer 19 will be described.

  The control computer 19 reads the drawing data of the sample 2 recorded on the magnetic disk by the input unit 20. The read drawing data is temporarily stored in the pattern memory 21 for each frame area 52.

  The drawing data for each frame area 52 stored in the pattern memory 21, that is, the frame information composed of the drawing position and drawing graphic data, etc. is corrected by the drawing data correction unit 31 as described above, and then subjected to data analysis. The data is sent to a subfield deflection amount calculation unit 28, a blanking circuit 24, a beam shaper driver 25, a main deflector driver 26, and a sub deflector driver 27 via a pattern data decoder 22 and a drawing data decoder 23.

  The pattern data decoder 22 generates blanking data based on the drawing data and sends it to the blanking circuit 24. Further, desired beam shape data is created based on the drawing data and is sent to the subfield deflection amount calculation unit 28 and the beam shaper driver 25.

  The subfield deflection amount calculation unit 28 calculates the deflection amount (movement distance) of the electron beam for each shot in the subfield 53 from the beam shape data created by the pattern data decoder 22. The calculated information is sent to the settling time determination unit 29, and the settling time corresponding to the movement distance by the sub deflection is determined.

  The settling time determined by the settling time determination unit 29 is sent to the deflection control unit 30, and then the deflection control unit 30 measures the blanking circuit 24, the beam shaper driver 25, the main pattern while timing the pattern drawing. It is appropriately sent to either the deflector driver 26 or the sub deflector driver 27.

  In the beam shaper driver 25, a predetermined deflection signal is applied to the shaping deflector 14 of the optical system 10, and the shape and size of the electron beam 54 are controlled.

  The drawing data decoder 23 creates positioning data for the subfield 53 based on the drawing data, and sends this data to the main deflector driver 26. Next, a predetermined deflection signal is applied from the main deflector driver 26 to the main deflector 15, and the electron beam 54 is deflected and scanned to a predetermined position in the subfield 53.

  The drawing data decoder 23 generates a control signal for scanning the sub deflector 16 based on the drawing data. After the control signal is sent to the sub deflector driver 27, a predetermined sub deflection signal is applied from the sub deflector driver 27 to the sub deflector 16. Drawing in the subfield 53 is performed by repeatedly irradiating the electron beam 54 after the settling time has elapsed.

  According to the electron beam drawing method of the present embodiment, drawing can be carried out after accurately evaluating the stability of the main deflection amplifier, and thus drawing with high accuracy is possible.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, although the electron beam is used in the above embodiment, the present invention is not limited to this, and the present invention can be applied to the case where other charged particle beams such as an ion beam are used.

DESCRIPTION OF SYMBOLS 1 Sample chamber 2 Mask 3 Stage 4 Stage drive circuit 5 Position circuit 6 Electron gun 7, 8, 9, 11, 12 Various lenses 10 Optical system 13 Blanking deflector 14 Molding deflector 15, 130 Main deflector 16 Sub deflector Device 17 First aperture 18 Second aperture 19 Control computer 20 Input unit 21 Pattern memory 22 Pattern data decoder 23 Drawing data decoder 24 Blanking circuit 25 Beam shaper driver 26 Main deflector driver 27 Sub deflector driver 28 Subfield Deflection amount calculation unit 29 Settling time determination unit 30, 230 Deflection control unit 31 Drawing data correction unit 32 Detector 33 Detection unit 34 A / D conversion unit 51 Pattern to be drawn 52 Frame region 53 Subfield 54 Electron beam 100 Evaluation mark 200 main bias Area

Claims (5)

A deflection amplifier used in the main deflector in a charged particle beam drawing apparatus that deflects the charged particle beam and draws a predetermined pattern using a main deflector and a sub deflector arranged on the optical path of the charged particle beam. An evaluation method,
Irradiating a charged particle beam to a predetermined position of a main deflection area defined by a deflection width of the main deflector, and after a predetermined time, a mark made of a material having a reflectance different from that of a base material constituting the main deflection area, Deflection characterized by irradiating the charged particle beam to a position on both the ground and the mark to detect reflected charged particles as a current value, and evaluating the deflection amplifier based on a fluctuation amount of the current value Amplifier evaluation method.   2. The deflection amplifier according to claim 1, wherein the reflected charged particles are detected as a current value by changing a distance from a predetermined position of the main deflection region to a position covering both the base and the mark. Evaluation methods.   2. The deflection amplifier evaluation method according to claim 1, wherein the reflected charged particles are detected as a current value by changing the predetermined time. A charged particle beam drawing method for drawing a predetermined pattern on a sample on a stage by deflecting the charged particle beam using a main deflector and a sub deflector arranged on an optical path of the charged particle beam,
Irradiating a charged particle beam to a predetermined position of a main deflection area defined by a deflection width of the main deflector, and after a predetermined time, a mark made of a material having a reflectance different from that of a base material constituting the main deflection area, Irradiating the charged particle beam to a position on both the ground and the mark to detect reflected charged particles as a current value, and drawing the predetermined pattern after the fluctuation amount of the current value becomes constant Characterized charged particle beam writing method. The distance from a predetermined position of the main deflection region to a position applied to both the base and the mark is changed, the reflected charged particles are detected as a current value, and a settling time is determined from the current value. The charged particle beam drawing method according to claim 4.

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