JP2010219481A - Charged particle beam drawing device and position measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for measuring a highly accurate position by correcting a non-leaner error in a direction orthogonal to a direction to move a stage so as to be drawn toward the drawing direction. <P>SOLUTION: The charged particle beam drawing device includes a movable stage, a drive portion which moves the stage in a first direction to draw in a drawing direction and controls its driving so that the stage vibrates in a second direction orthogonal to the first direction at a predetermined speed and a predetermined amplitude while moving the stage in the first direction, a measurement portion which measures the moving position of the stage in the second direction using a laser, a filter circuit which attenuates a component of a predetermined frequency domain from a value measured by the measurement portion in the second direction, and a drawing portion which draws a pattern by radiating a charged particle beam to a specimen using movement position data of the stage which have passed through the filter circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a charged particle beam drawing apparatus and a position measuring method, and more particularly to a stage position measuring method by laser length measurement.

  Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating a pattern among semiconductor manufacturing processes. In recent years, with the high integration of LSI, circuit line widths required for semiconductor devices have been reduced year by year. In order to form a desired circuit pattern on these semiconductor devices, a highly accurate original pattern (also referred to as a reticle or a mask) is required. Here, the electron beam (electron beam) drawing technique has an essentially excellent resolution, and is used for producing a high-precision original pattern.

  FIG. 14 is a conceptual diagram for explaining the operation of a conventional variable shaping type electron beam drawing apparatus. The variable shaped electron beam (EB) drawing apparatus operates as follows. In the first aperture 410, a rectangular opening for forming the electron beam 330, for example, a rectangular opening 411 is formed. Further, the second aperture 420 is formed with a variable shaping opening 421 for shaping the electron beam 330 having passed through the opening 411 of the first aperture 410 into a desired rectangular shape. The electron beam 330 irradiated from the charged particle source 430 and passed through the opening 411 of the first aperture 410 is deflected by the deflector, passes through a part of the variable shaping opening 421 of the second aperture 420, and passes through a predetermined range. The sample 340 mounted on a stage that continuously moves in one direction (for example, the X direction) is irradiated. That is, the drawing area of the sample 340 mounted on the stage in which the rectangular shape that can pass through both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is continuously moved in the X direction. Drawn on. A method of creating an arbitrary shape by passing both the opening 411 of the first aperture 410 and the variable shaping opening 421 of the second aperture 420 is referred to as a variable shaping method.

  The electron beam drawing apparatus requires highly accurate alignment of the stage. In general, the position of the stage is measured by a laser length measurement system using a laser interferometer. However, when the position of the stage is measured by a laser length measurement system using a laser interferometer, the measured position data includes a nonlinear error. With the miniaturization of patterns, such nonlinear errors have come to affect the drawing accuracy. Therefore, the inventor has devised a method for reducing the nonlinear error component during the stage movement with a low-pass filter (see, for example, Patent Document 1).

  Here, in the electron beam drawing apparatus, the drawing area of the sample to be drawn is virtually divided into strip-shaped stripe areas, and each stripe area is set as a drawing unit area in each stripe area (for example, the X direction). The pattern is drawn on the sample 340 while moving the stage. When the drawing of one stripe area is completed, the stage is moved in a direction perpendicular to the drawing area (for example, the Y direction) and moved onto the next stripe area. Therefore, the non-linear error component generated when moving the stage in a certain direction at a predetermined speed or a variable speed has a relatively high frequency. Therefore, the non-linear error component is low-pass filtered using the method of Patent Document 1. It was possible to reduce it.

  On the other hand, while the stage is moved in such a fixed direction, the stage is not moved in an orthogonal direction (for example, the Y direction) in terms of drive control of the stage. Therefore, the stage position should be constant. In practice, however, minute fluctuations also occur in the Y direction. For example, there is an influence such as distortion of the traveling system of the stage. If the position of the stage in the Y direction is measured by the laser length measurement system in a state where these minute fluctuations are generated, a nonlinear error is included in the measured position data. However, in the case of these minute fluctuations, since the generation frequency of the non-linear error component is low, it is difficult to remove the non-linear error component using the low-pass filter using the method of Patent Document 1.

JP 2007-33281 A

  As described above, while the stage is moved in a fixed direction during drawing, it is difficult to remove non-linear errors due to minute fluctuations occurring in the orthogonal direction that should have stopped. Therefore, it may be difficult to measure a highly accurate position.

  The present invention overcomes such problems and provides a method for measuring a highly accurate position by correcting a non-linear error in a direction orthogonal to the direction in which the stage is moved so as to be drawn toward the drawing direction. Objective.

A charged particle beam drawing apparatus according to one embodiment of the present invention includes:
A movable stage,
The stage is moved in the first direction so that drawing is performed in the drawing direction, and the stage is moved in the first direction, and a predetermined speed and a predetermined amplitude are set in a second direction orthogonal to the first direction. A drive unit for controlling the drive so that the stage vibrates at
A measurement unit that measures the moving position of the stage in the second direction using a laser;
A filter circuit for attenuating a component in a predetermined frequency region from the measurement value of the measurement unit in the second direction;
A drawing unit that draws a pattern by irradiating the sample with a charged particle beam using the moving position data of the stage that has passed through the filter circuit;
It is provided with.

  The drawing unit preferably includes a deflector that deflects the charged particle beam, and the predetermined amplitude is preferably a width that can be deflected by the deflector.

  The filter circuit is disposed in parallel with the low-pass filter, the pair of high-pass filters and low-pass filters connected in series, the first measurement value passed through the low-pass filter, and one set of It is preferable to have a combining unit that combines the high-pass filter and the second measurement value that has passed through the low-pass filter.

The position measurement method of one embodiment of the present invention includes:
The stage on which the sample is placed is moved in the first direction so that the sample is drawn in the drawing direction, and the second direction orthogonal to the first direction is moved while moving the stage in the first direction. A step of driving and controlling the stage to vibrate at a predetermined speed and a predetermined amplitude;
Measuring a moving position of the stage moving in the first direction while oscillating in the second direction using a laser; and
Using a low-pass filter set to a predetermined cut-off frequency, removing a non-linear error component from the measurement value measured in the second direction, and outputting the result;
It is provided with.

  In addition, a low-pass filter was used to remove the nonlinear error component using a pair of high-pass filter and low-pass filter set to the same cutoff frequency as the predetermined cutoff frequency, resulting in a measured value. It is preferable that the method further includes a step of correcting the phase delay.

The charged particle beam drawing apparatus according to another aspect of the present invention includes:
A movable stage,
A drive unit that controls driving so that the stage vibrates at a predetermined speed and a predetermined amplitude in a first direction and a second direction orthogonal to the first direction when drawing,
A measurement unit that measures the moving position of the stage in the first and second directions using a laser;
A filter circuit for attenuating a component in a predetermined frequency region from the measurement value of the measurement unit in the first and second directions;
A drawing unit that draws a pattern by irradiating the sample with a charged particle beam using the moving position data of the stage that has passed through the filter circuit;
It is provided with.

The position measurement method according to another aspect of the present invention includes:
A step of driving and controlling the stage to vibrate at a predetermined speed and a predetermined amplitude in a first direction and a second direction orthogonal to the first direction when drawing,
Measuring the moving position of the vibrating stage in the first and second directions using a laser;
Using a low-pass filter set to a predetermined cut-off frequency, removing a non-linear error component from each measured value measured in the first and second directions, and outputting the result;
A position measuring method comprising:

  According to the present invention, since the non-linear error component in the orthogonal direction that has been in a so-called stopped state can be removed, a more accurate position can be measured. Since a position with higher accuracy can be measured, highly accurate drawing can be performed.

1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 1. FIG. It is a figure for demonstrating the mode of a stage movement. It is a block diagram which shows the internal structure of a filter circuit. FIG. 4 is a diagram showing a flowchart of a position measurement method in the first embodiment. It is a figure which shows the relationship between the position of ay direction, and time. It is a figure which shows the relationship between the output of a x direction, and a position. It is a figure which shows the relationship between the gain with respect to the frequency of the data of the position component after LPF passage, and a phase. It is a figure which shows the relationship between the gain and phase with respect to the frequency of the data of the position component data of the y direction after passing 1 set of HPF and LPF. It is a figure which shows the relationship between the gain and phase with respect to the frequency of the data which synthesize | combined the data of the position component of the y direction after passing LPF, and the data of the position component of the y direction after passing 1 set of HPF and LPF. It is a figure which shows the transfer function type | formula of a digital filter. 6 is a diagram illustrating an example of a gain change amount and a phase change amount in the y direction after passing through the filter according to Embodiment 1. FIG. It is a figure which shows an example of the waveform of the data of the position component with the case where it does not pass through the case where the combination filter in Embodiment 1 is passed. It is a figure for demonstrating the comparison with a prior art. It is a conceptual diagram for demonstrating operation | movement of a variable shaping type | mold electron beam exposure apparatus.

  Hereinafter, in the embodiment, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and a beam using charged particles such as an ion beam may be used.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment.
1, the drawing apparatus 100 includes an electron column 102, a drawing chamber 103, a drive unit 106, a laser interferometer 300, a position calculation unit 109, a filter circuit 110, a drawing calculation circuit 111, and a drive control unit 112. . The drawing apparatus 100 draws a desired pattern on the sample 101 using the electron beam 200. The electronic lens barrel 102 is an example of a drawing unit. The laser interferometer 300 is an example of a measurement unit.

  In the electron column 102, there are an electron gun 201, an illumination lens 202, a first aperture 203, a projection lens 204, a deflector 205, a second aperture 206, an objective lens 207, a sub deflector 209, and a main deflector 208. have. An XY stage 105 is disposed in the drawing chamber 103. On the XY stage 105, a mirror 104 for laser length measurement is arranged. A sample 101 to be drawn is placed on the XY stage 105. The laser interferometer 300 includes a laser head 107 serving as a laser light source, a mirror 104 on the XY stage 105, an optical system 113, and a light receiving unit 108. Here, one set of laser interferometers 300 is shown, but it goes without saying that at least two sets of laser interferometers 300 for the x direction and y direction are arranged. The laser interferometer 300 is connected to the position calculation unit 109. The position calculation unit 109 is connected to the filter circuit 110. The drive control unit 112 is connected to the drive unit 106, and the drive unit 106 moves the XY stage 105 in the x direction and the y direction. A drive control unit 112 and a filter circuit 110 are connected to the drawing arithmetic circuit 111.

  The electron beam 200 emitted from the electron gun 201 illuminates the entire first aperture 203 having a rectangular hole, for example, a rectangular hole, by the illumination lens 202. Here, the electron beam 200 is first formed into a rectangle, for example, a rectangle. Then, the electron beam 200 of the first aperture image that has passed through the first aperture 203 is projected onto the second aperture 206 by the projection lens 204. The position of the first aperture image on the second aperture 206 is controlled by the deflector 205, and the beam shape and size can be changed. Then, the electron beam 200 of the second aperture image that has passed through the second aperture 206 is focused by the objective lens 207, deflected by the sub-deflector 209 and the main deflector 208, and is movably arranged. The desired position of the sample 101 on the stage 105 is irradiated.

  FIG. 2 is a diagram for explaining how the stage moves. The drawing (exposure) surface is virtually divided into a plurality of strip-like stripe regions that can deflect the electron beam 200 by the main deflector 208. Each stripe area becomes a drawing unit area. When a pattern is drawn on the sample 101, the main deflector 208 draws on one stripe region while the XY stage 105 is continuously moved in the longitudinal direction of the stripe region by the driving unit 106, for example, in the x direction. A desired pattern is drawn in the SF by the sub deflector 209 while the deflection position follows the reference position on the desired subfield (SF). When drawing of one SF is completed, the main deflector 208 draws a desired pattern in the SF similarly with the sub deflector 209 while following the deflection position to the reference position on the next SF. Such an operation is repeated to draw one stripe region in the x direction. When drawing of one stripe region is completed, the XY stage 105 is stepped in the Y direction by the drive unit 106, and the drawing operation of the next stripe region is similarly performed in the x direction (in this case, the opposite direction). The moving time of the XY stage 105 can be shortened by making the drawing operation of each stripe region meander. Here, when drawing one stripe region, the XY stage 105 only moves in the direction opposite to the drawing direction (for example, the + x direction) (−x direction), and without moving in the y direction, the + x direction. The drawing proceeds. However, this generates a low-frequency nonlinear component due to minute fluctuations in the y direction as described above.

  Therefore, in the first embodiment, when drawing of each stripe region is advanced, drive control is performed so that the XY stage 105 vibrates at a predetermined amplitude A and speed V in the y direction. For example, if the XY stage 105 is moving in the −x direction, the XY stage 105 is driven so as to move in the −x direction while drawing a wavy curve (for example, a sine curve) as shown in the lower diagram of FIG. Control.

  FIG. 3 is a block diagram showing the internal configuration of the filter circuit. The position of the XY stage 105 installed in the drawing chamber 103 in the x direction and the position in the y direction are measured by a laser interferometer 300 that is an example of a laser measurement system. In FIG. 3, a set of circuits for measuring the position in the x direction or the y direction is described, but they are arranged for the x direction and the y direction, respectively.

  In the first embodiment, since the nonlinear component in the y direction is considered as a problem, the following description will be given with emphasis on position measurement in the y direction.

  The measurement value in the y direction measured by the laser interferometer 300 for measuring the y direction is converted into position component data in the y direction by the position calculation unit 109. Then, the data of the position component in the y direction applied to the low-pass filter (hereinafter referred to as LPF) 122 set to a predetermined cutoff frequency is passed. On the other hand, the data of the position component in the y direction is passed through a set of high-pass filters (hereinafter referred to as HPF) 124 and LPF 126 which are arranged in parallel with LPF 122 and set to the same cutoff frequency as LPF 122. . The HPF 124 and the LPF 126 are connected in series. Then, the data that has passed through the LPF 122 and the data that has passed through the pair of HPF 124 and LPF 126 are added and synthesized by an adder 128 as an example of a synthesis unit. The synthesized value is output to the drawing arithmetic circuit 111. Similar processing is performed on the measurement value in the x direction measured by the laser interferometer 300 for x direction measurement.

FIG. 4 is a diagram showing a flowchart of the position measuring method according to the first embodiment.
In S (step) 502, as described above, as the y-direction vibration control and measurement process, the drive unit 106 controlled by the drive control unit 112 moves the XY stage 105 in, for example, the x direction (first direction) in a certain stripe region. The XY stage 105 is controlled to vibrate at a velocity V and an amplitude A in the y direction (second direction) orthogonal to the x direction while moving the stage in the x direction. Thereby, the sample 101 on the XY stage 105 is drawn in the drawing direction (−x direction). In this state, the laser interferometer 300 in the x direction uses the laser to measure the movement position in the x direction of the XY stage 105 that is moving in the x direction while vibrating in the y direction. The y-direction laser interferometer 300 uses a laser to measure the movement position in the y direction of the XY stage 105 that is moving in the x direction while vibrating in the y direction. That is, the laser beam is applied to the mirror 104 mounted on the XY stage 105 installed in the drawing chamber 103 from the laser head 107 serving as a laser projector via the optical system 113, and the reflected laser beam is reflected. Light is received by the light receiving unit 108 via the optical system 113. The measurement value measured by the laser interferometer 300 is converted into position component data by the position calculator 109. Here, as described above, the position component data includes a nonlinear error component.

  FIG. 5 is a diagram illustrating the relationship between the position in the y direction and time. Conventionally, the stage has not been moved in the y direction in terms of stage drive control. Therefore, the stage position should be constant. However, actually, as shown in FIG. 5A, a minute fluctuation of the linear component occurs in the y direction. In the case of laser length measurement, a nonlinear error component is included due to an optical path (optical path) problem. Specifically, a vertical wave and a horizontal wave mixed in the laser beam interfere with each other, thereby causing a nonlinear error. That is, the reflection of a mirror or the like in the laser measurement system causes a horizontal wave component to interfere with the vertical wave and a vertical wave component to the horizontal wave, thereby generating a non-linear error. Such a nonlinear error component becomes data on the linear component. When the position of the stage in the y direction is measured by the laser interferometer 300 in a state where such minute fluctuations are occurring, the measured position data includes a low-frequency nonlinear error. On the other hand, as shown in FIG. 5B, the vibration position of the linear component is applied by forcibly applying the vibration with the predetermined amplitude A and the predetermined speed V in the y direction as in the first embodiment. The non-linear error included in the position data at the time of measuring can be made high frequency.

The generation frequency of the non-linear component has a relationship of stage speed / non-linear component wavelength. The generation frequency of the nonlinear component is dominant, for example, ¼ of the laser wavelength λ of the laser interferometer 300, that is, λ / 4. Other frequencies such as λ / 2 are also generated, but the effect is particularly great if the component of λ / 4 can be removed. For example, when a He—Ne laser is used as the laser of the laser interferometer 300, the wavelength λ of the He—Ne laser is 633 nm. Therefore, 633 nm / 4 = 158 nm. Further, when the nonlinear component is removed by the LPF, when the frequency is set higher than the position component of the XY stage 105, for example, the set frequency is desirably 2 kHz or more. Therefore, the stage speed V at which the nonlinear component having a wavelength of 158 nm is a frequency of 2 kHz or more is V ≧ 158 × 10 ⁻⁶ mm × 2000 Hz = 0.3 mm / s. Therefore, the stage speed V when vibrating in the y direction is preferably, for example, 0.3 mm / s or more.

  The amplitude A is preferably in a range that does not affect drawing. That is, it is desirable that the width be deflectable by the sub deflector 209. For example, several μm to several tens of μm is desirable.

  FIG. 6 is a diagram illustrating the relationship between the output in the x direction and the position. In the x direction, ideally, the distance from the measuring instrument to the object to be measured and its position data should have a complete linearity relationship. That is, the change in position and its output should be proportional. However, as shown in FIG. 6, in the case of laser length measurement, a nonlinear error component is included due to an optical path (optical path) problem. Therefore, the nonlinear error component becomes data on the linear component.

  In S504, as the nonlinear error component removal step, the nonlinear error component is removed from the measurement value in the y direction measured in the measurement step. Usually, since such a nonlinear error component has a higher frequency than the position component of the XY stage 105, the position error converted from the measured value in the y direction of the laser interferometer 300 is obtained by passing the LPF 122 as the first filter. From the data, a frequency region including a nonlinear error component in a high frequency region is attenuated at a predetermined cutoff frequency. Also in the x direction, the nonlinear error component is removed from the measured value in the x direction measured in the same manner.

FIG. 7 is a diagram showing the relationship between the gain and phase with respect to the frequency of the position component data after passing through the LPF.
As shown in FIG. 7A, by setting the LPF 122 to a predetermined cut-off frequency, the nonlinear error component in the high frequency region is obtained from the position component data converted from the measurement value of the laser interferometer 300 in the y direction. The containing frequency region can be attenuated and substantially eliminated. However, as shown in FIG. 7B, the passage of the LPF 122 causes a phase delay in the position component data in the y direction. If the position of the XY stage 105 in the y direction is determined based on the data that has passed through the LPF 122 as it is, the real time property may be deteriorated due to the phase delay, and a beam irradiation position described later may be shifted.

  In S506, as the phase correction component forming step, a data component for correcting the above-described phase delay is formed. An HPF 124 is connected in parallel with the LPF 122 as a second filter, and attenuates components other than the frequency region that the LPF 122 attenuates from the measured value at the same cutoff frequency as the LPF 122.

  An LPF 126 is connected in series with the HPF 124 as a third filter, and attenuates the same frequency domain component as the LPF 122 attenuates from the measured value at the same cutoff frequency as the LPF 122.

FIG. 8 is a diagram showing the relationship between the gain and phase with respect to the frequency of the data of the position component in the y direction after passing through a pair of HPF and LPF.
As shown in FIG. 8B, the phase of the data of the position component data in the y direction is accelerated by passing the HPF 124. Then, as shown in FIG. 8A, components other than the frequency region attenuated by the LPF 122 are attenuated. Further, by passing through the LPF 126, the same frequency domain component as that of the frequency domain attenuated by the LPF 122 is attenuated. The position component data is formed by advancing the phase and attenuating the frequency regions on both sides with the same cut-off frequency as the LPF 122.

  In step S <b> 508, the phase delay generated in the position component data in the y direction as a result of using the LPF 122 as the phase correction step is corrected. An adder 128, which is an example of a synthesizer, uses the positional component data converted from the measurement value in the y direction of the laser interferometer 300 that has passed through the LPF 122, and The position component data converted from the measurement value is added and combined, and the combined value is output to the drawing operation circuit 111.

FIG. 9 shows the relationship between the gain and the phase with respect to the frequency of the data obtained by synthesizing the position component data in the y direction after passing through the LPF and the position component data in the y direction after passing through a pair of HPF and LPF. FIG.
As shown in FIG. 9B, by adding and synthesizing two data, the phase lag can be corrected and the frequency region where the phase lag starts can be shifted to the high frequency side. Further, as shown in FIG. 9A, the gain attenuation start position can also be slightly shifted to the high frequency side.

  By adjusting the cutoff frequency of the LPF 122, HPF 124, and LPF 126 so that the gain and phase do not shift in the necessary frequency region, the nonlinear error component at the y-direction position can be removed while suppressing the phase shift.

  Here, either the HPF 124 or the LPF 126 may be arranged on the upstream side (primary side). That is, the order of the HPF 124 and the LPF 126 may be first. The same effect can be obtained regardless of which is arranged upstream.

  The filter circuit 110 can be configured as a digital filter. For example, it may be incorporated as a program in an FPGA (Field Programmable Gate Array). In other words, the “filter unit” can be configured by a program operable by a computer. Or you may make it implement by not only the program used as software but the combination of hardware and software. Alternatively, a combination with firmware may be used. When configured by a program, the program is recorded on a recording medium such as a magnetic disk device, a magnetic tape device, an FD, or a ROM (Read Only Memory).

FIG. 10 is a diagram illustrating a transfer function equation of the digital filter.
As shown in FIG. 9B, the transfer function equation of the LPF 122 is as follows, where the cutoff frequency is f _n , the time constant is τ _n (where τ _n = 1 / (2πf _n )), and the Laplace operator is S. 1 / (1 + τ ₁ · S). Similarly, the transfer function equation of the HPF 124 can be represented by τ ₂ · S / (1 + τ ₂ · S). Similarly, the transfer function equation of the LPF 126 can be expressed by 1 / (1 + τ ₃ · S). Therefore, as shown in FIG. 10A, the transfer function G (S) = 1 / (1 + τ ₁ · S) + τ ₂ · S / (1 + τ ₂ · S) · 1 / of the combined digital filter of the entire filter unit 110 (1 + τ ₃ · S).

Here, the cutoff frequencies of the LPF 122, the HPF 124, and the LPF 126 are preferably the same cutoff frequency. However, this does not exclude a slight deviation within a range where the above-described effects of removing the nonlinear error component and correcting the phase delay are recognized. For the same cutoff frequency, τ ₁ = τ ₂ = τ ₃ .

FIG. 11 is a diagram illustrating an example of a gain change amount and a phase change amount in the y direction after passing through the filter according to the first embodiment. In FIG. 11, as an example, when the cut-off frequency f ₁ of the LPF 122, the cut-off frequency f ₂ of the HPF 124, and the cut-off frequency f ₃ of the LPF 126 are all 5 kHz, and all are 3 kHz, all are 1 kHz. In this case, the gain change amount and the phase change amount at the position where the frequency f is 100 Hz and the gain change amount and the phase change amount at the position where the frequency f is 6.3 kHz are shown.

  In the example of FIG. 11, when all the cut-off frequencies are 1 kHz, for example, there is almost no gain change amount and no phase change amount at a position of a frequency of 100 Hz required for position detection. It can be seen that the amount of gain change at the 3 kHz position is large (attenuates to 32%). Therefore, by passing through the combination filter in the first embodiment, the nonlinear error component can be removed and the phase delay can be improved.

  FIG. 12 is a diagram illustrating an example of a waveform of position component data with and without passing through the combination filter in the first embodiment. FIG. 12A shows an example of the waveform of the position component data when the filter is OFF, that is, when the combination filter is not passed. In FIG. 12A, it can be seen that the amplitude of the waveform greatly fluctuates due to the nonlinear error component. On the other hand, when the filter is turned on, that is, through the combination filter in the first embodiment, it can be seen that the nonlinear error component is removed and the waveform amplitude is reduced as shown in FIG.

  As described above, by passing the measured value in the y direction through the LPF 122 set to a predetermined cutoff frequency for the y direction, the nonlinear error component is removed from the measured value in the y direction. On the other hand, the measured value in the y direction is passed through a set of HPF 124 and LPF 126 set to the same cutoff frequency as the predetermined cutoff frequency for the y direction. As a result of using the LPF 122, the measured value in the y direction is obtained. Correct the phase lag that occurred.

  The above operation is similarly performed in the x direction. Thereby, the non-linear error component can be removed also in the x direction, and the phase delay can be corrected.

  As described above, the drawing operation circuit 111 inputs the data of the position components in the x direction and the y direction from which the phase delay is corrected and the nonlinear error component is removed, so that the XY stage 105 is input using the input position component data. Can be detected with high accuracy. Therefore, the drawing arithmetic circuit 111 can realize high-precision pattern position accuracy with such high-precision position data.

  In S <b> 510, as a drawing process, the drawing arithmetic circuit 111 mainly performs irradiation so that the electron beam 200 is deflected and followed by a desired position of the sample 101 on the XY stage 105 that continuously moves in the drawing chamber 103. The deflector 208 and the sub deflector 209 are controlled. A drawing unit configured by each component in the electron column 102 draws a pattern by irradiating the sample 101 with the electron beam 200 using the movement position data of the XY stage 105 that has passed through the filter circuit 110.

  FIG. 13 is a diagram for explaining comparison with the prior art. FIG. 13A shows a case where the electron beam exposure is performed without passing through the combination filter in the first embodiment as a conventional technique. Since the accurate position of the XY stage 105 cannot be measured due to the non-linear error component, the desired position of the sample 101 on the XY stage 105 cannot be specified accurately. As a result, the shot position of the electron beam is shifted. FIG. 13A shows a state in which the pattern is disconnected due to the positional deviation. On the other hand, by passing through the combination filter in the first embodiment, the nonlinear error component is removed, and the position of the XY stage 105 can be measured with high accuracy. As a result, as shown in FIG. 13B, there is no deviation in the electron beam shot position, and a predetermined pattern can be drawn at a desired position.

  In the forced vibration in the y direction, the velocity becomes 0 at the maximum amplitude in the y direction and at the maximum amplitude in the −y direction. Therefore, it is more preferable to avoid the beam irradiation to the sample 101 in the vicinity of both points. is there.

  Further, as an effect of passing through the combination filter in the first embodiment, digital noise can be further reduced. As such digital noise, for example, a position error may occur due to fluctuation of LSB (Least Significant Bit) of position data of the laser interferometer 300. By passing through the combination filter in the first embodiment, the LSB fluctuation is eliminated and the position accuracy can be improved.

Embodiment 2. FIG.
In the first embodiment, for example, the example in which the nonlinear error component in the y direction is removed by applying the forced vibration in the y direction while moving in the x direction has been described. However, the present invention is not limited to this. In the second embodiment, for example, a case in which drawing is performed while stopped while performing a step-and-repeat operation will be described. The apparatus configuration is the same as that shown in FIGS. Further, the position measurement method is the same as the case where “y direction” is read as “x, y direction” in S502 of FIG. The drawing apparatus 100 described above can also be used when drawing in a stopped state while performing a step-and-repeat operation. When drawing by such an operation method, the stage is not moved in the x and y directions at the drawing position in terms of stage drive control. Therefore, the stage position should be constant. In practice, however, minute fluctuations can also occur in the x and y directions. This generates a low-frequency nonlinear component due to minute fluctuations in the x and y directions as described above. Therefore, it becomes difficult to remove the nonlinear components in both directions by the filter.

  Therefore, when drawing by such an operation, forced vibration as shown in FIG. 5B is applied to both the x direction and the y direction at the position where the stage should be stopped. By such forced vibration, the frequency of the nonlinear error component in both the x direction and the y direction can be increased. The amplitude and speed of the forced vibration may be the same as in the above-described example performed only in the y direction, for example.

  In S502, as described above, as the x and y direction vibration control and measurement process, the drive unit 106 controlled by the drive control unit 112 moves the XY stage 105 in, for example, the x direction (first direction) in a certain stripe region. To step and repeat. Then, drive control is performed so that the XY stage 105 vibrates at the velocity V and the amplitude A in the x direction and the y direction (second direction) orthogonal to the x direction at the position where the conventional stopping is performed after the step. Drawing is performed in such a state. In this state, the laser interferometer 300 in the x direction measures the movement position in the x direction of the XY stage 105 that vibrates in the x direction using a laser. The y-direction laser interferometer 300 uses a laser to measure the movement position in the y direction of the XY stage 105 vibrating in the y direction. That is, the laser beam is applied to the mirror 104 mounted on the XY stage 105 installed in the drawing chamber 103 from the laser head 107 serving as a laser projector via the optical system 113, and the reflected laser beam is reflected. Light is received by the light receiving unit 108 via the optical system 113. The measurement value measured by the laser interferometer 300 is converted into position component data by the position calculator 109. Here, as described above, the position component data includes a nonlinear error component.

  In S504, as the nonlinear error component removal step, the nonlinear error component is removed from the measured values in the x and y directions measured in the measurement step. Usually, since such a nonlinear error component has a higher frequency than the position component of the XY stage 105, each position converted from the measured value in the y direction of the laser interferometer 300 by passing through the LPF 122 as the first filter. From the component data, a frequency region including a nonlinear error component in a high frequency region is attenuated at a predetermined cutoff frequency. Also in the x direction, the nonlinear error component is removed from the measured value in the x direction measured in the same manner.

  In step S <b> 508, the phase delay generated in the position component data in the y direction as a result of using the LPF 122 as the phase correction step is corrected. An adder 128, which is an example of a synthesizer, uses the positional component data converted from the measurement value in the y direction of the laser interferometer 300 that has passed through the LPF 122, and The position component data converted from the measurement value is added and combined, and the combined value is output to the drawing operation circuit 111. Similarly, in the x direction, the phase delay generated in the position component data in the x direction is corrected.

  As described above, the drawing operation circuit 111 inputs the data of the position components in the x direction and the y direction from which the phase delay is corrected and the nonlinear error component is removed, so that the XY stage 105 is input using the input position component data. Can be detected with high accuracy. Therefore, the drawing arithmetic circuit 111 can realize high-precision pattern position accuracy with such high-precision position data.

  In S <b> 510, as a drawing process, the drawing arithmetic circuit 111 mainly performs irradiation so that the electron beam 200 is deflected and follows the desired position of the sample 101 on the XY stage 105 that is forcibly vibrated in the drawing chamber 103. The deflector 208 and the sub deflector 209 are controlled. A drawing unit configured by each component in the electron column 102 draws a pattern by irradiating the sample 101 with the electron beam 200 using the movement position data of the XY stage 105 that has passed through the filter circuit 110. After drawing, the same operation is performed by stepping to the next position.

  As described above, in S502 of FIG. 4, the “y direction” is replaced with “x, y direction”, and the x, y direction vibration control and measurement process (S502) and the nonlinear error component removal process (S502) shown in FIG. By performing each step of S504) and the phase correction component forming step (S506), both the x-direction and the y-direction have been described above even when drawing is performed while the step-and-repeat operation is stopped. The same effect as that in the position measurement in the y direction can be obtained.

  In the above description, an electron beam is used in each embodiment. However, the present invention is not limited to this, and a charged particle beam including ions or the like may be used. Further, the variable shaping type electron beam drawing apparatus is described as an example of the drawing apparatus. However, the drawing apparatus is not limited to this, and may be a drawing apparatus using an electron beam that is not changed.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the drawing apparatus 100 is omitted, it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all position measurement apparatuses, drawing apparatuses, and position measurement methods that include elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Drawing apparatus 101,340 Sample 102 Electron barrel 103 Drawing chamber 104 Mirror 105 XY stage 106 Drive part 107 Laser head 108 Light receiving part 109 Position calculation part 110 Filter circuit 111 Drawing calculation circuit 112 Drive control part 113 Optical system 122,126 LPF
124 HPF
128 Adder 200 Electron Beam 201 Electron Gun 202 Illumination Lens 203, 206, 410, 420 Aperture 204 Projection Lens 205 Deflector 207 Objective Lens 208 Main Deflector 209 Sub Deflector 300 Laser Interferometer 330 Electron Beam 411 Opening 421 Variable Shaped Opening 430 Charged particle source

Claims (7)

A movable stage,
The stage is moved in the first direction so as to be drawn toward the drawing direction, and the predetermined speed is set in the second direction orthogonal to the first direction while moving the stage in the first direction. And a drive unit that drives and controls the stage to vibrate with a predetermined amplitude,
A measurement unit that measures a moving position of the stage in the second direction using a laser;
A filter circuit for attenuating a component in a predetermined frequency region from the measurement value of the measurement unit in the second direction;
A drawing unit that draws a pattern by irradiating the sample with a charged particle beam using the movement position data of the stage that has passed through the filter circuit;
A charged particle beam drawing apparatus comprising: The drawing unit has a deflector for deflecting a charged particle beam,
The charged particle beam drawing apparatus according to claim 1, wherein the predetermined amplitude is a width that can be deflected by the deflector. The filter circuit is
A low-pass filter,
A set of a high pass filter and a low pass filter arranged in parallel with the low pass filter and connected in series;
A combining unit that combines the first measurement value that has passed through the low-pass filter and the second measurement value that has passed through the set of high-pass filter and low-pass filter;
The charged particle beam drawing apparatus according to claim 1, wherein: The stage on which the sample is placed is moved in the first direction so that the sample is drawn in the drawing direction, and the stage is orthogonal to the first direction while moving the stage in the first direction. Driving and controlling the stage to vibrate at a predetermined speed and a predetermined amplitude in a second direction;
Measuring a moving position of the stage moving in the first direction while oscillating in the second direction with respect to the second direction using a laser;
Using a low-pass filter set to a predetermined cut-off frequency, removing a non-linear error component from the measured value measured in the second direction, and outputting the result;
A position measuring method comprising:   As a result of using the low-pass filter when removing the nonlinear error component by using a set of high-pass filter and low-pass filter set to the same cutoff frequency as the predetermined cutoff frequency, it occurs in the measured value. 5. The position measuring method according to claim 4, further comprising a step of correcting the phase delay. A movable stage,
A drive unit that drives and controls the stage to vibrate at a predetermined speed and a predetermined amplitude in a first direction and a second direction orthogonal to the first direction when drawing,
A measurement unit that measures the moving position of the stage in the first and second directions using a laser;
A filter circuit for attenuating a component in a predetermined frequency region from the measurement value of the measurement unit in the first and second directions;
A drawing unit that draws a pattern by irradiating the sample with a charged particle beam using the movement position data of the stage that has passed through the filter circuit;
A charged particle beam drawing apparatus comprising: A step of driving and controlling the stage to vibrate at a predetermined speed and a predetermined amplitude in a first direction and a second direction orthogonal to the first direction when drawing,
Measuring a moving position of the vibrating stage in the first and second directions using a laser;
Using a low-pass filter set to a predetermined cut-off frequency, removing a nonlinear error component from each measurement value measured in the first and second directions, and outputting the result;
A position measuring method comprising: