JP2007141797A - Electron microscope control device, electron microscope control method, control program, recording medium having control program recorded thereon, electron microscope system, and electron beam irradiation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron microscope control device capable of controlling the intensity and/or acceleration voltage of an electron beam applied to a sample to a low value and enabling acquisition of an electron microscope image having a high S/N ratio. <P>SOLUTION: An electron beam irradiation matrix setting part 65 sets an electron beam irradiation matrix indicating a time series of a two-dimensional pattern of the electron beam to be emitted from a projector 8. The electron beam irradiation matrix is set to include a plurality of pixels to be irradiated with the electron beam among the pixels included in the two-dimensional pattern, and such that two-dimensional patterns whose number is equal to the number of the pixels included in the two-dimensional pattern are formed into time-series two-dimensional patterns independent from each other. A matrix computing part 66 calculates a vector indicating the electron microscope image of the sample by performing matrix computation based on the electron beam irradiation matrix and a vector representing time-series detection signals detected by the secondary electron detector. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electron microscope control apparatus and an electron microscope control method in an electron microscope for observing the surface state of a sample by irradiating a sample as an observation target with an electron beam and detecting secondary electrons emitted from the sample. The present invention relates to a control program, a recording medium recording the control program, and an electron microscope system.

  2. Description of the Related Art Conventionally, an electron microscope that observes the surface state of a sample by irradiating a sample as an observation target with an electron beam and detecting secondary electrons emitted from the sample has been used. In this electron microscope, the amount of charge injected into the sample is determined by the detection sensitivity of the secondary electrons emitted from the sample. That is, the improvement in detection sensitivity of secondary electrons enables observation of an electron microscope with a sample whose structure and physical properties are easily changed by electron beam irradiation.

On the other hand, the surface observation of the sample using the two-dimensional electron beam array is equivalent to focusing the two-dimensional electron beam array on the resist surface in the semiconductor lithography technique. Here, secondary electrons emitted from the resist are detected, and control is performed to focus the two-dimensional electron beam array on the resist surface using this detection signal. That is, the problem of improving the detection sensitivity of secondary electrons in two-dimensional electron beam irradiation is a common problem in the semiconductor lithography technology.
As shown in FIG. 16, it is no exaggeration to say that the performance of the semiconductor element is left to the precision of microfabrication by the semiconductor lithography technique (that is, the reduction of the minimum processing dimension). Until now, the resolution of fine processing by lithography using light (electromagnetic waves) in the visible light band is determined depending on the wavelength of the light. For this reason, in order to further miniaturize the fine processing, as shown in FIG. 17, light in a shorter wavelength band such as EUV (Extreme UltraViolet rays) or X-rays from the visible light region is used. There was a need.

  However, it is not easy to realize such an optical system used for the generation of the light generation device or the reduction of the light beam, so that the light in the short wavelength band is relatively easy to generate and control. It was considered to use the (line) for fine processing by semiconductor lithography technology.

  However, since an existing semiconductor manufacturing (lithography) apparatus using an electron beam directly draws a circuit pattern of a semiconductor element with a single electron beam, all of the circuit patterns in a highly integrated semiconductor element are drawn. However, it takes a lot of exposure time (several hours to several tens of hours). In other words, the electron beam exposure method that breaks down the fine processing limit depending on the wavelength of light is a one-dimensional exposure method of "one-stroke writing", so it takes a lot of exposure time to directly expose the entire wafer, The problem is that it is not practical.

  In recent years, in an exposure method using an electron beam, in order to shorten the exposure time, a two-dimensional electron beam batch exposure method for drawing the above-mentioned pattern batch has been developed. As such a two-dimensional electron beam batch exposure method, a SCALPEL method (AT & T) and a PRIVAIL method (IBM) have been proposed.

  In the SCALPEL system, as shown in FIG. 18 (a), the electron beam 31 is irradiated onto the reticle 32 having the scattering portion 32b patterned on the surface of the membrane 32a, and the emitted electron beam is applied to the electron lens 33 and the back surface. In this system, a circuit having the above pattern is formed by irradiating and exposing a metal thin film 35 coated with an electronic register by an optical system having a focal plane filter 34. The SCALPEL method is also described in Patent Document 1.

  In the PRIVAIL method, as shown in FIGS. 19 (a) and 19 (b), an Si substrate 44 having holes 44a corresponding to the pattern is used as a reticle, and the electron beam 41 is irradiated onto the Si substrate 44. In this method, the electron beam 41 having passed through the holes 44a is irradiated and exposed on a wafer 47 provided with a metal thin film coated with an electron beam resist, using an optical system. Examples of the optical system include an electron lens 42, an illumination lens 43 including an electron beam axis deflection yoke 43a, a collimation lens 45, and a projection lens 46 including a contrast aperture 46. However, the PRIVAIL method has a disadvantage that the Si substrate 44 having a hollow portion as shown in FIG. The PRIVAIL method is also described in Patent Document 2.

  However, the SCALPEL method has a problem that the resolution is remarkably lowered at that portion because the electron beam 31 needs to pass through the membrane 32a as shown in FIG.

  The PRIVAIL method irradiates the wafer 47 with each small pattern obtained by dividing the pattern when forming a complicated pattern, for example, a pattern having a hollow as shown in FIG. However, it is necessary to align the small patterns with each other, and due to the accuracy of the alignment, there is a problem that the resolution is remarkably lowered (the resolution is limited to 100 nm) as in the SCALPEL system.

Moreover, in both of the above systems, there is a problem that troublesome operations such as manufacturing of the reticle and installation of the reticle in a vacuum chamber are necessary. As described above, each system has the fundamental problem described above.
US Pat. No. 5,260,151 (Publication date: November 9, 1993) U.S. Pat. No. 5,466,904 (publication date: November 14, 1995)

  When considering an electron microscope using a two-dimensionally arranged electron beam irradiation source, the method initially assumed is to irradiate the sample with an electron beam in order for each pixel of the electron beam irradiation source, In this method, secondary electrons emitted by using one secondary electron detector are detected to form a two-dimensional image.

  In this method, for example, observation of nanostructures of organic and bio-based samples, when the subject is likely to be accompanied by changes in structure and physical properties by electron beam irradiation, and it is necessary to set both irradiation time and acceleration voltage low, electron microscope images at high speed Need to get. Thus, when the irradiation time has to be set short, it is considered that the amount of secondary electrons emitted from the sample decreases as it falls below the detection device noise, and high detection sensitivity of secondary electrons is essential. Become. That is, when the detection sensitivity of secondary electrons is low, it is impossible to observe the surface of the sample. Therefore, there is a need for high secondary electron detection sensitivity that allows microscopic observation even when the total amount of charges injected into the sample is as low as possible.

  On the other hand, in electron beam lithography using a two-dimensional electron beam irradiation source, it is necessary to focus the two-dimensional electron beam array on the resist surface. Here, as described above, in order to focus the two-dimensional electron beam array on the resist surface, it is necessary to detect secondary electrons emitted from the resist. That is, it is equivalent to performing microscopic observation of a sample using an irradiation source. In order to improve the resolution of the exposure, the acceleration voltage is set high, the electron wave is kept at a short wavelength, and the resolution is lowered by the electrostatic interaction force between the beams and the charges injected into the sample. In order to prevent this, it is essential to set the total injected charge amount to the sample low. Therefore, it is inevitably necessary to improve the secondary electron detection sensitivity in the electron microscope using the above-described two-dimensionally arranged electron beam irradiation source also in lithography.

  An object of the present invention is to control an electron microscope that makes it possible to obtain an electron microscope image having a high S / N even when the total amount of injected electrons into the sample is set low and the amount of all emitted secondary electrons is sufficiently small. An object is to provide an apparatus, an electron microscope control method, a control program, a recording medium recording the control program, and an electron microscope system.

  In order to solve the above problems, an electron microscope control apparatus according to the present invention emits an electron beam irradiation unit that irradiates a sample to be observed with a two-dimensional pattern by an electron beam, and is emitted from the sample by irradiation with the electron beam An electron microscope control apparatus for generating an electron microscope image of a sample by an electron beam irradiation apparatus including a secondary electron detector for detecting secondary electrons, the two-dimensional electron beam to be emitted from the electron beam irradiation unit Based on a pattern setting means for setting a pattern in time series, a time-series two-dimensional pattern set by the pattern setting means, and a time-series detection signal detected by the secondary electron detector, An image generation means for generating an electron microscope image, and the pattern setting means emits an electron beam among pixels included in the two-dimensional pattern. Each time-series two-dimensional pattern is set so as to include pixels that are to be included, and the same number of two-dimensional patterns as the number of all pixels included in the observation area are time-series so as to become independent two-dimensional patterns. This is the configuration set in

  In addition, an electron microscope control method according to the present invention detects an electron beam irradiation unit that irradiates a sample to be observed with a two-dimensional pattern by an electron beam, and detects secondary electrons emitted from the sample by the electron beam irradiation. An electron microscope control method for generating an electron microscope image of a sample by an electron beam irradiation apparatus including a secondary electron detector, wherein a two-dimensional pattern of an electron beam to be emitted from the electron beam irradiation unit is set in time series An image for generating an electron microscope image of a sample based on a pattern setting step, a time-series two-dimensional pattern set by the pattern setting step, and a time-series detection signal detected by the secondary electron detector And the pattern setting step is irradiated with an electron beam among the pixels included in the two-dimensional pattern. Each time-series two-dimensional pattern is set so as to include pixels, and a number of two-dimensional patterns equal to the number of all pixels included in the observation region are set in time series so as to become independent two-dimensional patterns. It is a method of setting.

  In the above configuration or method, first, an electron beam is irradiated in time series as a two-dimensional pattern to a sample.

  Here, as described above, when an electron microscope is realized using an electron beam irradiation source arranged two-dimensionally, a method of irradiating a sample with an electron beam in order for each pixel of the electron beam irradiation source Can be considered. However, in this method, only one electron beam corresponding to one pixel is irradiated by one electron beam irradiation. When the amount of secondary electrons is small, in order to increase the S / N, the electron beam It is necessary to increase the current density, and the above-described problems occur.

  On the other hand, according to the above configuration or method, the electron beam irradiation unit irradiates the sample with an electron beam as a two-dimensional pattern. Therefore, it is possible to irradiate a plurality of pixels with an electron beam in one electron beam irradiation. Therefore, even if the intensity of the electron beam corresponding to one pixel is relatively low, the charge injection amount for the entire sample can be ensured, so that the same pixel is irradiated with the electron beam multiple times in time series. Therefore, it is possible to sufficiently ensure the S / N of the detection signal by the secondary electron detector.

  In addition, the same number of two-dimensional patterns as the number of all pixels included in the observation region are set in time series so that they become independent two-dimensional patterns. Therefore, if the number of pixels in the electron microscopic image of the sample is an unknown number, detection results based on the same number of independent two-dimensional patterns as the unknown number can be obtained, so that all unknown numbers can be calculated.

  That is, according to the above-described configuration or method, it is possible to reduce the intensity and acceleration voltage of the electron beam applied to the sample and to obtain an electron microscope image with a high S / N. Therefore, for example, it is possible to provide an electron microscope control apparatus that can be suitably used for nano-structure observation of organic / bio-based samples that are easily demanded in recent years and are likely to undergo structural / physical property changes due to energy of electron beams. it can.

  In the electron microscope control apparatus according to the present invention, in the above configuration, the pattern setting means includes at least one two-dimensional pattern among the two-dimensional patterns set in time series. The pixel may be configured to include a plurality of pixels irradiated with the electron beam.

  In the above configuration, among the two-dimensional patterns set in time series, at least one two-dimensional pattern is set to include a plurality of pixels irradiated with the electron beam among the pixels included in the two-dimensional pattern. The Therefore, even if the intensity of the electron beam corresponding to one pixel is relatively low, the charge injection amount for the entire sample can be ensured, so that the S / N of the detection signal by the secondary electron detector can be ensured. It becomes possible.

  In the electron microscope control apparatus according to the present invention, in the configuration described above, the pattern setting unit is a matrix in which vectors representing each two-dimensional pattern are arranged in rows and arranged in the column direction along a time series. Then, a matrix that is a regular matrix is set as an electron beam irradiation matrix, and the image generating means converts the electron beam irradiation matrix and a vector representing a time-series detection signal detected by the secondary electron detector. It is good also as a structure provided with the matrix calculating part which calculates the vector which shows the electron microscope image of a sample by performing matrix calculation based on it.

  According to the above configuration, the time-series two-dimensional pattern set by the pattern setting unit is represented as an electron beam irradiation matrix, and the matrix calculation is performed by the matrix calculation unit provided in the image generation unit, thereby performing an electron microscope image of the sample. Is calculated. That is, an electron microscope image can be easily generated by using a known calculation method called matrix calculation.

  In the electron microscope control apparatus according to the present invention, in the configuration described above, the pattern setting unit includes more pixels than the half of the total number of pixels among the pixels included in each two-dimensional pattern. It is good also as a structure set to become.

  According to the above configuration, each two-dimensional pattern is set so that the number of pixels irradiated with the electron beam is larger than half of the total number of pixels, so that observation with a higher S / N can be realized. it can.

  In the electron microscope control apparatus according to the present invention, in the configuration described above, the pattern setting unit is a matrix in which vectors representing each two-dimensional pattern are arranged in rows and arranged in the column direction along a time series. Then, a matrix that is a regular matrix is set as an electron beam irradiation matrix, and the image generating means converts the electron beam irradiation matrix and a vector representing a time-series detection signal detected by the secondary electron detector. A matrix calculation unit that calculates a vector indicating an electron microscope image of the sample by performing matrix calculation based on the matrix calculation, and the electron beam irradiation matrix is a Hadamard matrix or a M-series and M-sequence shift row vector The configuration may be an orthogonal matrix.

  As in the above configuration, the electron beam irradiation matrix is a Hadamard matrix or a regular matrix having M-sequence and M-sequence shifts as row vectors. Therefore, among the pixels included in each two-dimensional pattern, the electron beam is It is possible to set an electron beam irradiation matrix that is more than half of the total number of pixels and is an orthogonal matrix.

  Further, the electron microscope control apparatus according to the present invention is the detection signal output from the secondary electron detector when the image generating means performs electron beam irradiation based on each two-dimensional pattern in the above configuration. In consideration of the time-series noise signal superimposed on the sample, an electron microscope image of the sample may be generated.

  According to the above configuration, in addition to the time-series two-dimensional pattern set by the pattern setting means and the time-series detection signal detected by the secondary electron detector, it is output from the secondary electron detector. An electron microscope image of the sample is generated in consideration of a time-series noise signal superimposed on the detection signal. Therefore, it is possible to provide a higher S / N electron microscope image.

  In the electron microscope control apparatus according to the present invention, in the above configuration, the electron beam irradiation apparatus is incident as a light pattern generation unit for generating a two-dimensional light pattern as the electron beam irradiation unit. An electron amplifying unit for generating an electron beam array based on the light pattern, amplifying and emitting the electron beam array, and an electron beam lens unit for accelerating and focusing the electron beam array The light pattern generation control unit may further include a light pattern generation control unit that controls emission of the light pattern by the light pattern generation unit based on the time-series two-dimensional pattern set by the pattern setting unit.

  The electron beam irradiation apparatus used in the above configuration can draw a two-dimensional exposure pattern in a lump by irradiating and exposing an electron beam array based on a two-dimensional light pattern onto a sample, thereby shortening the exposure time. It can be made. Further, since the electron beam array amplified based on the light pattern is used, the intensity of the electron beam applied to the sample can be increased, the exposure time can be further shortened, and the drawing speed can be improved.

  In addition, the above configuration can reduce the interaction between micro electron beams and the electrostatic interaction force between scattered electrons inside the electron beam resist caused by using an electron beam array that is an aggregate of micro electron beams. The accuracy of the drawing pattern can be improved.

  As a result, since the above-described configuration can improve the accuracy and drawing speed of the drawing pattern, it becomes an electron beam irradiation apparatus capable of rapidly performing electron beam irradiation with higher resolution such as a resolution of 5 nm or less.

  With respect to such an electron beam irradiation apparatus, since the emission of the light pattern is controlled by the light pattern generation control means, it is possible to provide an electron microscope image with high resolution at high speed.

  The electron microscope control device may be realized by a computer. In this case, the control program for the electron microscope control device that realizes the electron microscope control device by the computer by causing the computer to operate as the respective means. And a computer-readable recording medium on which it is recorded also fall within the scope of the present invention.

  In addition, an electron beam irradiation apparatus according to the present invention detects an electron beam irradiation unit that irradiates a sample to be observed with a two-dimensional pattern by an electron beam, and detects secondary electrons emitted from the sample by the electron beam irradiation. And a secondary electron detector.

  Conventionally, in an electron microscope, a sample is observed by scanning a one-dimensional electron beam. In this case, only one electron beam corresponding to one pixel is irradiated by one electron beam irradiation. When the amount of secondary electrons is small, the current density of the electron beam is set to increase the S / N. It is necessary to make it high, and the above-described problems occur.

  On the other hand, according to the above configuration, the electron beam irradiation unit irradiates the sample with an electron beam as a two-dimensional pattern. Therefore, it is possible to irradiate a plurality of pixels with an electron beam in one electron beam irradiation. Therefore, even if the intensity of the electron beam corresponding to one pixel is relatively low, the same pixel is irradiated with the electron beam a plurality of times in time series. N can be secured sufficiently.

  In the electron beam irradiation apparatus, if the electron beam lens unit can further accelerate the electron beam array, the electron beam can be shortened, so that the drawing pattern can be made finer. The accuracy and the drawing speed of the drawing pattern can be improved. Further, if the electron beam lens unit can further align the electron beam array, the accuracy of the drawing pattern can be further improved.

  In the electron beam irradiation apparatus, the electron amplifying unit amplifies electrons. A plurality of cylindrical microchannels are arranged so that an axial direction of the microchannel is along an optical axis direction of the optical pattern. It is preferable that they are formed adjacent to each other in a direction orthogonal to the optical axis direction.

  According to the above configuration, a plurality of cylindrical microchannels are adjacent to each other in a direction perpendicular to the optical axis direction, so that the axial direction of the microchannel is along the optical axis direction of the optical pattern. Forming. From this, an electron beam array corresponding to the light pattern can be obtained while suppressing the interaction between the micro electron beams obtained by dividing each micro channel. As a result, the electron beam array can be obtained more reliably.

  In the electron beam irradiation apparatus, the electron amplification unit may include a photoelectric film that converts incident photons into electrons and emits them on the incident side of the optical pattern.

  According to the above configuration, even if the light intensity of the light pattern from the light pattern generation unit is small, the photoelectric pattern is provided on the incident side of the light pattern in the electronic amplification unit, so that the electronic pattern corresponding to the light pattern is provided. It becomes possible to obtain an electron beam array more reliably by entering and amplifying the electron amplifier.

  In the electron beam irradiation apparatus, the electron amplification unit may be an avalanche type photoconductor film.

  Further, the light pattern generation unit may be a liquid crystal projector that generates the light pattern, or an electroluminescence light emitting unit that generates the light pattern.

  According to the above configuration, the light pattern from the light pattern generation unit is emitted to the electronic amplification unit using the light pattern generation unit that can easily change the light pattern that is a two-dimensional image, such as a liquid crystal projector or an electroluminescence light emission unit. Therefore, the correction of the light pattern in the correction unit can be simplified, and the improvement of the accuracy of the drawing pattern by the correction can be stabilized.

  In the said electron beam irradiation apparatus, the said light pattern generation | occurrence | production part may be provided with the light source and the mask pattern for producing | generating the said light pattern with the light from the said light source. According to the above configuration, by using the mask pattern, the light pattern generation unit can be simplified, and the overall cost can be reduced. In addition, when the distortion generated in the drawing pattern can be predicted to some extent, the above configuration can suppress the distortion and improve the accuracy of the drawing pattern by using a mask pattern corrected according to the prediction. Is possible.

  The electron beam irradiation apparatus preferably further includes a correction unit for correcting the light pattern so as to reduce distortion generated in the pattern drawn by the electron beam array.

  According to the above configuration, since the correction unit for correcting the light pattern is provided so as to reduce the distortion generated in the pattern drawn by the electron beam array, the pattern drawn by the electron beam array can be changed from the light pattern side. By correcting, it can be ensured and speeded up to a desired drawing pattern.

  In the electron beam irradiation apparatus, the correction unit controls the light pattern generation unit to generate a reverse distortion light pattern generation unit so as to cancel a distortion generated in the electron beam array. May be provided.

  According to the above configuration, by providing the reverse distortion light pattern generation unit for generating the reverse distortion light pattern so as to cancel the distortion generated in the electron beam array, the accuracy of the drawing pattern can be improved by the cancellation.

  In the electron beam irradiation apparatus, the correction unit includes a split light pattern generation unit that controls the light pattern generation unit to generate a plurality of split light patterns that interpolate each other with the light pattern. May be.

  According to the above configuration, each of the plurality of divided patterns that interpolate from each of the plurality of divided light patterns by including the divided light pattern generation unit for generating a plurality of divided light patterns that interpolate each other. An electron beam array can be obtained. By irradiating the same area of the electron beam resist with the respective divided pattern electron beam arrays along the time axis at different times, a drawing pattern corresponding to the optical pattern can be formed on the electron beam resist.

  At this time, the interval between adjacent micro electron beams in each divided pattern electron beam array used in time division can be increased. Thereby, the electrostatic interaction force between the micro electron beams adjacent to each other and the scattered electrons inside the electron beam resist in each divided pattern electron beam array can be reduced.

  As a result, in the above configuration, since a desired drawing pattern with less distortion can be obtained on the electron beam resist, it is possible to increase the accuracy of the drawing pattern by the divided pattern electron beam array.

  The electron beam irradiation device may further include a grid-like electrostatic lens unit on the emission side of the electron amplification unit in order to suppress variations in the emission angle of the electron beam array from the electron amplification unit.

  According to the above configuration, by passing the electron beam array through the grid portion in the grid-like electrostatic lens portion, the electron beam array can be made parallel to each other and the variation in the emission angle is suppressed, so that the resolution is reduced due to the variation. Can be reduced. In addition, since the variation in the emission angle can be suppressed, the similarity with the above-described optical pattern can be improved, and the accuracy of the drawing pattern can be improved.

  As described above, the electron beam irradiation apparatus according to the present invention sets the two-dimensional pattern of the electron beam to be emitted from the electron beam irradiation unit in time series, and the time set by the pattern setting unit. An image generating means for generating an electron microscope image of the sample based on a series of two-dimensional patterns and a time-series detection signal detected by the secondary electron detector; Of the pixels included in the pattern, each of the time-series two-dimensional patterns is set so as to include a plurality of pixels irradiated with the electron beam, and the number of two-dimensional patterns equal to the total number of pixels included in the observation region is set. In this configuration, the two-dimensional patterns that are independent from each other are set in time series. As a result, it is possible to reduce the intensity and acceleration voltage of the electron beam applied to the sample and to obtain an electron microscope image with a high S / N.

  An embodiment of the present invention is described below with reference to the drawings.

(Configuration of electron microscope system)
FIG. 2 shows a configuration of the electron microscope system according to the present embodiment. As shown in the figure, the electron microscope system includes an electron beam irradiation unit 51 and a computer system 52.

  The electron beam irradiation unit 51 includes a vacuum chamber 1, a stage 2, a mechanical drive 3, a stage position monitor 4, a projector (light pattern generation unit) 8, an optical lens 9, a photoelectric film 10, and an MCP (Micro Channel Plate) (electronic amplification unit). ) 11, the electron beam lens unit 12 is provided.

In the electron beam irradiation unit 51, the box-shaped vacuum chamber 1 capable of maintaining a vacuum state therein is provided so that the degree of vacuum is 10 ⁻⁶ Torr or less. In this embodiment, the degree of vacuum is set to 10 ⁻⁸ Torr.

  A stage (mounting table) 2 for mounting the sample 5 to be exposed is attached to the bottom of the vacuum chamber 1 so as to be movable in a two-dimensional horizontal direction. A mechanical drive 3 for moving and driving the stage 2 is provided inside or outside the vacuum chamber 1 so as to be controlled by a controller 17 described later. A stage position monitor 4 for monitoring the position of the stage 2 (that is, the movement position) is attached so as to notify the controller 17 described later of the monitor position.

  In the vicinity of the top of the vacuum chamber 1, a projector 8 for generating a two-dimensional light pattern 13 corresponding to the circuit pattern of the semiconductor element emits the light pattern 13 from the light emitting surface of the projector 8 to the outside. It is provided as follows.

  Examples of the projector 8 include a transmissive liquid crystal system and a single plate DLP (Digital Light Processing) system. A trace amount of photons present in the dark portion of the light pattern 13 is multiplied by 1000 times or more by the MCP 11 (details will be described later), and finally irradiated to the sample 5, so that the contrast ratio is generally high. The plate type DLP method is more desirable. Examples of projectors that support this single-plate DLP method include DMD (Digital Micromirror Device).

  In the optical path between the projector 8 and the MCP 11, a convex or concave optical lens 9 for efficiently entering the light pattern 13 on the incident side of the MCP 11 may be provided as necessary. In addition, it is desirable that a photoelectric film 10 that converts incident light into electrons and emits it is provided on the incident side of the MCP 11.

  In the above example, the two-dimensional light pattern 13 is emitted from the projector 8 and applied to the MCP 11. However, a photomask constituted by a liquid crystal shutter or the like is installed on the light incident side of the MCP 11. A light source that irradiates the entire surface of the photomask with uniform light may be provided. In the case of this configuration, the light emitted from the light source is converted into a two-dimensional light pattern 13 by a photomask, and this light pattern 13 is irradiated onto the MCP 11. Here, finally, since the patterned electron beam array 14 is focused by the electron beam lens unit 12 to be described later, the resolution of the photomask may be relatively low. That is, it is not necessary to provide an expensive photomask with high resolution.

  Further, an EL light emitting unit in which organic electroluminescence (hereinafter abbreviated as EL) light emitting elements are arranged on a matrix can be used in place of the projector 8 and the optical lens 9 described later. In this case, the EL light emitting unit is disposed so as to be in contact with the photoelectric film 10, and the light pattern 13 emitted from the EL light emitting unit is directly projected onto the photoelectric film 10 at the same magnification. In any case, at the stage of irradiating the photoelectric film 10 with the light pattern 13 (in other words, the incident position on the MCP 11 described later), it is sufficient that the light pattern 13 has an accuracy of μm level.

  The light pattern 13 emitted from the projector 8 and collected by the optical lens 9 is applied to the MCP 11 through the photoelectric film 10. The MCP 11 generates a patterned electron beam array 14 based on the incident light pattern 13. The electron beam array 14 amplifies the electron beam emitted from the photoelectric film 10 from several thousand times to several tens of million times by the MCP 11. Details of the configuration of the MCP 11 will be described later.

  Examples of the material of the photoelectric film 10 include multi-alkali (Na—K—Sb—Cs), bialkali (Sb—Rb—Ce, Sb—K—Cs), Ce—Te, Ag—O—Cs, GaAs, and GaAsP. Etc. are typical examples. In the visible region, CdS is widely used, and (Cu, Ag, Sb, etc.) is generally added to increase sensitivity. In this embodiment, CdS is used.

  When the photons of the light pattern 13 have energy higher than the work function of the semiconductor portion on the inner surface of the microchannel of the MCP 11, the photoelectric film 10 can be omitted. Further, even when the light pattern 13 by UV having a short wavelength of 200 nm or less is irradiated on the inside of the MCP 11, secondary electrons are generated from the semiconductor portion on the inner surface, and the electron beam array corresponding to the light pattern 13 14 can be obtained, and thus the photoelectric film 10 is unnecessary. For the production of the light pattern 13 by UV, a UV photomask may be placed on the light incident side of the MCP 11.

  An electron beam lens unit 12 for accelerating, focusing, aligning, and projecting the electron beam array 14 is provided along the optical path of the patterned electron beam array 14 emitted from the MCP 11. Details of the configuration of the electron beam lens unit 12 will be described later.

  The electron beam emitted from the MCP 11 and accelerated and focused by the electron beam array 14 reaches the surface of the sample 5, whereby secondary electrons corresponding to the surface state of the sample 5 are emitted. The secondary electron detector 15 detects secondary electrons emitted from the sample 5.

  The computer system 52 includes a controller 17 as a computer main body, a display 18 as a display output unit, and an input unit 19 such as a keyboard and a mouse. The controller 17 controls the operations of the projector 8, the electron beam lens unit 12, and the mechanical drive 3, and performs a process of generating an electron microscope image based on the detection result signal in the secondary electron detector 15. Details of the configuration of the controller 17 will be described later.

(Configuration of MCP)
Next, the configuration of the MCP 11 will be described. As shown in FIGS. 3 and 4, the MCP 11 has a configuration in which a plurality of cylindrical microchannels 11 a that amplify electrons are provided. The microchannels 11a are arranged side by side in a two-dimensional direction in which the respective axial directions are parallel to each other and perpendicular to the axial direction. The MCP 11 is provided so that the axial direction of each microchannel 11 a is parallel to the optical axis direction of the light pattern 13 incident on the MCP 11.

  Examples of the cylindrical shape include a cylindrical shape, a square cylindrical shape, and a hexagonal cylindrical shape, but a cylindrical shape is used in the present embodiment for ease of manufacture.

  The production of the MCP 11 will be described below by taking up one microchannel 11a of the MCP 11. First, for example, a plurality of cylindrical portions are formed in parallel to each other in the thickness direction of the main body 11b of the lead glass plate. The diameter of the cylindrical part is set to 1 μm to 100 μm, and the ratio of the length of the cylindrical part to the diameter (L / d) is set to 20 to 200, more preferably 40 to 100. In this embodiment, the diameter is set to 2 μm to 10 μm, and the ratio (L / d) is set to 40 to 80. Moreover, although the axial direction of a cylindrical part may be parallel along the normal line direction of the surface of a lead glass plate, and may incline to about 8 degrees, it is parallel in this embodiment.

Next, when one electron collides with the inner surface of each cylindrical portion, a semiconductor portion 11c having a dynode structure that emits a plurality of secondary electrons in a direction along the collision direction is formed. The semiconductor part 11c is formed as a resistive semiconductor part on the surface of the main body 11b by reducing the main body 11b at a high temperature of 250 ° C. to 450 ° C. in a hydrogen atmosphere. The resistance value in the thickness direction of the main body 11b of the semiconductor portion 11c is set to 10 ⁸ Ω to ^{10 10} Ω.

  Subsequently, the electrodes 11d and 11e are respectively formed by vapor deposition of nichrome or inconel on both surfaces of the main body 11b of the lead glass plate in which the cylindrical semiconductor portions 11c are formed in the thickness direction. Produced.

In such a microchannel 11a, a DC voltage of 600V to 1100V is applied between the electrodes 11d and 11e, with the electron incident side being negative and the electron emission side being positive, as shown in FIG. When one electron 25 collides with the semiconductor portion 11c in the microchannel 11a from the electrode 11d side on the electron incident side, a plurality of secondary electrons 27 are emitted in the direction along the collision direction, and the electrons are emitted. Each electron 27 collides with the semiconductor portion 11c and repeatedly emits more electrons, whereby one electron 25 becomes 5 × 10 ² to 3 × 10 ⁵ electron beams 29. It will be emitted. The CHEVRON shown in FIG. 5 is one in which the MCP 11 is formed in two stages.

  Therefore, the above-described electron beam array 14 is a collection of a plurality of micro electron beams respectively corresponding to the respective micro channels 11a. The plurality of micro electron beams are separated from each other, and are along the optical path direction of the light pattern 13 and the longitudinal direction of each of the micro channels 11a. However, the plurality of micro electron beams do not necessarily have to be parallel to the optical path direction and the longitudinal direction, and may be inclined as in the case of focusing.

  A HARP (High-gain Avalanche Rushing amorphous Photoconductor) film can be used as an avalanche type photoconductor film as a substitute for the above-described photoelectric film 10 + MCP11. The HARP film means an amorphous selenium film to which a high pressure is applied. When light is incident on the surface of the HARP film, photoelectric conversion occurs in the HARP film, and a charge is avalanche amplified in the film to emit electrons. Therefore, by making the light pattern 13 incident on one surface of the HARP film, a patterned electron beam array 14 is emitted from the other surface of the HARP film.

  In addition, instead of the projector 8 + photoelectric film 10 + MCP11, a surface-conduction electron emitter (SED) is used as a device for generating a patterned electron beam array 14 by voltage control and exposing a resist. ), At least one selected from a device group consisting of a field emission display (FED) field emitter display (FED, Field Emission Display) such as a silicon dip or molybdenum tip dip, carbon nanotube array, and diamond thin film Can be used.

(Configuration of electron beam lens)
Next, the configuration of the electron beam lens unit 12 will be described. As shown in FIG. 6, the electron beam lens unit 12 includes an accelerating tube unit 12a, a focusing lens unit 12b, an alignment multipole deflecting electrode unit 12c, and a projection lens unit 12d. It is the structure arranged along the direction. In the electron beam lens unit 12, it is sufficient that at least the focusing lens unit 12b is provided. If necessary, at least one of the acceleration tube unit 12a, the alignment multipolar deflection electrode unit 12c, and the projection lens unit 12d is used. May be provided.

  The acceleration tube portion 12a is for accelerating the electron beam array 14, shortening the wavelength of the electron beam, and finally improving the drawing resolution on the electron beam resist 7. The focusing lens portion 12b is for focusing the pattern in the in-plane direction orthogonal to the optical path direction of the patterned electron beam array 14. The multipole deflecting electrode portion 12c is for correcting distortion of the electron beam array 14 after passing through the focusing lens portion 12b. The projection lens unit 12d is for irradiating the sample 5 with the electron beam array 14 having passed through the multipole deflecting electrode unit 12c as a two-dimensional electron beam pattern 14a having a desired size.

  The electron beam of the electron beam array 14 is shortened to a wavelength of about 0.01 nm at 100 keV by the acceleration tube portion 12a such as an acceleration lens or an acceleration electrode. The electron beam array 14 having a reduced wavelength makes it possible to irradiate the sample 5 with a finer two-dimensional electron beam pattern 14a having a scale of 5 nm or less.

(Configuration of controller)
Next, the configuration of the controller 17 will be described with reference to FIG. As shown in the figure, the controller 17 includes a projector control unit (light pattern generation control means) 61, an electronic lens control unit 62, a detection signal receiving unit 63, a mechanical drive control unit 64, an electron beam irradiation matrix setting unit (pattern setting). Means) 65, a matrix operation unit (image generation unit) 66, an image processing unit (image generation unit) 67, a display control unit 68, and an input control unit 69.

  The projector control unit 61 controls the operation of the projector 8. Specifically, the projector control unit 61 controls to emit the light pattern 13 to be emitted from the projector 8 and also controls the emission timing of the light pattern 13.

  The electron lens control unit 62 controls the operation of the electron beam lens unit 12. The detection signal receiving unit 63 receives the detection signal output from the secondary electron detector 15 and performs A / D (Analog / Digital) conversion processing. The mechanical drive control unit 64 drives the mechanical drive 3 based on the position detection result of the stage 2 by the stage position monitor 4 and adjusts the stage position.

  The electron beam irradiation matrix setting unit 65 performs processing for setting an electron beam irradiation matrix to be described later. The electron beam irradiation matrix set by the electron beam irradiation matrix setting unit 65 is transmitted to the projector control unit 61, and the projector control unit 61 transmits the light pattern 13 according to the sequence of the two-dimensional pattern indicated in the electron beam irradiation matrix. Perform output control.

  The matrix calculation unit 66 performs a matrix calculation based on the electron beam irradiation matrix and the detection signal received by the detection signal reception unit 63, and performs processing for generating electron microscope image data. Details of this matrix operation will be described later.

  The image processing unit 67 performs processing for generating image data that can be displayed on the display 18 by performing image processing on the electron microscope image data generated by the matrix calculation unit 66.

  The display control unit 68 performs control to display information indicating an operation state in the controller 17 and image data generated by the image processing unit 67 on the display 18. The input control unit 69 performs processing for receiving an instruction input from the user received by the input unit 19.

(Two-dimensional electron beam pattern correction processing)
The projector control unit 61 serves as a correction unit for correcting the light pattern 13 so as to reduce the distortion generated in the two-dimensional electron beam pattern 14 a drawn by the electron beam array 14 that is accelerated, focused, aligned, and projected. Is also set to work.

  First, as a first example of the correction, there is correction of distortion in the electron beam lens unit 12. Since the electric field generated by the electron beam lens unit 12 has a spatial intensity distribution, the reduction rate differs between the center of the patterned electron beam array 14 to be focused and the pattern outline. In order to solve this, the projector control unit 61 causes the projector 8 to generate an incident light pattern (reverse distortion light pattern) that is a product of an inverse function of distortion generated in the electron beam lens unit 12 with respect to a desired pattern. Control. Therefore, the projector control unit 61 includes a reverse distortion light pattern generation unit.

  Accordingly, in the first example, in the electron beam lens unit 12, distortion generated in the two-dimensional electron beam pattern 14a drawn by the electron beam array 14 can be canceled by the incident light pattern. In other words, it is possible to irradiate the sample 5 with the two-dimensional electron beam pattern 14a at a normal electron beam resolution.

  As a result, in the first example, the two-dimensional electron beam pattern 14a can be irradiated with high accuracy and programmable by correcting from the light pattern 13 side. Therefore, for example, an electron microscope system with a higher resolution such as a resolution of 5 nm or less can be realized with high accuracy and low cost.

  Next, as a second example of the correction, as shown in FIGS. 7A and 7B, as the electron beam array 14 is focused by the electron beam lens unit 12 and approaches the sample 5, As shown in FIG. 7C, an example of avoiding the disadvantage that the interaction force between the adjacent micro electron beams 14b is increased and the resolution due to the scattering due to the interaction force is lowered will be described.

  Therefore, as shown in FIG. 8A, a plurality of divided light patterns 11a-1 to 11a- each composed of dots interpolating with each other from the light pattern 13 incident on each microchannel 11a which is each matrix of the MCP 11. 3 is generated by the projector control unit 61 so as to generate 3 in a time division manner. Since the divided light patterns 11a-1 to 11a-3 are formed so as to interpolate each other, as shown in FIG. 8B, when they are overlapped with each other, the original light pattern 13 is obtained. . Therefore, the projector control unit 61 includes a split light pattern generation unit.

  As described above, in the second example of the correction, the micro electron beam 14b based on the divided light patterns 11a-1 to 11a-3 irradiated onto the sample 5 has a wide interval, and thus the above interaction is performed. Inconvenience due to force can be suppressed. As a result, also in the second example of correction, it is possible to avoid a decrease in resolution, so that an ultra-high density LSI can be manufactured with higher accuracy, lower cost, and programmable.

  Further, in the electron microscope system according to the present embodiment, as shown in FIGS. 9A and 9B, in order to prevent a reduction in resolution due to variations in the emission angle of the electron beam array 14 from the MCP 11. In addition, a grid-like electrostatic lens portion 16 may be provided on the emission side of the MCP 11.

  In the grid-like electrostatic lens portion 16, each grid-like space portion 16a corresponding to each microchannel 11a of the MCP 11 has a space along the traveling direction of each amplified electron beam from each microchannel 11a. Are formed respectively. As a result, when a voltage is applied to the grid-like electrostatic lens portion 16, an attractive force is generated on the electron beam array 14 from the MCP 11, and the accelerated electron beam array 14 is moved to each grid-like space portion. By passing through 16a, it is possible to make them parallel to each other, suppress variations in the emission angle, reduce a decrease in resolution caused by the variations, and improve similarity to the light pattern 13 described above. It is possible to improve the accuracy of the two-dimensional electron beam pattern 14a.

  In this way, by using the microchannel 11a having a diameter of 10 μm and the MCP11 having a distance of 12 μm between the centers of the adjacent microchannels 11a, a rated 2 keV is applied to the electrodes 11d and 11e of the MCP11 to obtain a total exposure current. 10 mA, as shown in FIG. 10A, a micro electron beam 14 b of 0.5 μA is obtained per microchannel 11 a of the MCP 11, so that the conventional exposure using the same exposure current shown in FIG. It was found that the S / N was 40000 times that of an electron microscope using the electron beam 14c.

  This numerical value corresponds to the number of microchannels 11a formed in the MCP 11, and if the MCP 11 having a large number of microchannels 11a is used, the exposure speed is considered to increase in proportion thereto.

(Reference example of electron beam irradiation method)
The electron beam array 14 emitted from the MCP 11 is accelerated and focused as described above, and sequentially reaches the surface of the sample 5 in time series, whereby secondary electrons corresponding to the surface state of the sample 5 are emitted. The secondary electrons are detected by the secondary electron detector 15 and imaged by the matrix calculation unit 66 and the image processing unit 67 based on the detection signal, whereby an electron microscope image is obtained. Hereinafter, an electron beam irradiation method as a reference example which is an example of the embodiment of the present invention will be described with reference to FIG.

  In the example shown in FIG. 11, for the sake of simplicity, the total number of pixels of the two-dimensional light pattern 13 emitted from the projector 8 is 25 × 5 × 5, and this two-dimensional pattern is shown as a matrix. In each number in the matrix, 1 indicates a pixel on which electron beam irradiation is performed, and 0 indicates a pixel on which electron beam irradiation is not performed.

  In the matrix shown in A1, only the (1,1) pixel is 1, and in the matrix shown in A2, only the (2,1) pixel is 1. Only one pixel is 1. By preparing 25 such matrices and sequentially performing electron beam irradiation with a two-dimensional pattern based on these matrices, the electron beam irradiation is performed once for all the pixels.

  In the above case, the two-dimensional pattern irradiated in one electron beam irradiation can be expressed by a 25-dimensional (5 × 5 = 25 pixels) vector. Specifically, in FIG. 12, the matrices indicated by A1 and A2 can be represented by vectors indicated by B1 and B2, respectively. When B1 to B25 are arranged vertically, they can be represented by a 25 × 25 matrix shown in C. This 25 × 25 matrix is referred to as an electron beam irradiation matrix. This electron beam irradiation matrix shows a time series when all the pixels of the two-dimensional pattern are sequentially irradiated with the electron beam.

  When the electron beam irradiation method as described above is performed, as described above, in terms of S / N (signal to noise ratio), the influence on the sample 5 as a subject (such as structural change), and the sample 5 There is a big problem in terms of minimizing the charge-up. Although it is preferable to set the total charge injection amount as low as possible by lowering the electron beam intensity and acceleration voltage, in this case, the signal intensity corresponding to the amount of secondary electron emission from each pixel is lower than the device noise. In this case, there is a problem that observation becomes impossible.

(Electron beam irradiation method)
In order to solve the above problems, in this embodiment, a two-dimensional pattern irradiated in one electron beam irradiation is used as a pattern in which a plurality of pixels are irradiated with an electron beam, and these two-dimensional patterns are defined as predetermined. It is assumed that the electron beam irradiation is performed a plurality of times by changing the rule. For example, when the electron beam irradiation source is turned ON (set to 1 in the matrix) in half of the pixels included in the two-dimensional pattern, the secondary electron detector 15 detects the electron beam irradiation once. The signal increases by (total pixels) / 2 times. That is, since the detected signal intensity increases and each pixel is irradiated with an electron beam a plurality of times, noise is averaged and reduced in an operation for calculating an electron beam image. (Signal to noise ratio) will be improved. That is, since the detected signal intensity increases and each pixel is irradiated with an electron beam a plurality of times, noise is averaged and reduced in an operation for calculating an electron beam image. Will be improved. Thus, by irradiating an electron beam irradiation based on a two-dimensional pattern capable of improving the S / N several times for all the pixels, and performing arithmetic processing on the signal obtained by each electron beam irradiation, The amount of secondary electrons emitted can be calculated. Thereby, a two-dimensional electron microscope image can be obtained.

  For example, when the two-dimensional pattern is 5 × 5 pixels, the electron beam irradiation is performed 25 times with different two-dimensional patterns. Since there are 25 unknowns here, all unknowns can be calculated by performing electron beam irradiation with 25 different two-dimensional patterns (or orthogonal to each other in terms of a matrix).

(Specific example of calculation processing)
Hereinafter, a specific example of a two-dimensional pattern and an algorithm for obtaining an electron microscope image from the obtained signal will be described using the above-described electron beam irradiation matrix.

  First, let L × L electron beam irradiation matrix be matrix B. As defined above, the total number of pixels in the electron microscope image by this electron beam irradiation matrix is L. Further, an L-dimensional column vector indicating a time series of the amount of secondary electrons emitted from the sample 5 when the electron beam irradiation based on each two-dimensional pattern is performed is defined as a vector A. An L-dimensional column noise vector indicating a time series of noise superimposed on a detection signal output from the secondary electron detector 15 when electron beam irradiation based on each two-dimensional pattern is performed is a vector C. . Here, the vector C represents device noise, and is an output signal generated even when no secondary electrons are emitted from the sample 5. This noise is sufficiently larger than the Johnson noise caused by the signal when the injected charge amount is set low. An L-dimensional column vector indicating a time series of detection signals detected by the secondary electron detector 15 when electron beam irradiation based on each two-dimensional pattern is performed is a vector S. The relationship between the matrix B, vector A, vector C, and vector S is expressed by the following equation.

  In the case of the reference example described above, the matrix B is a unit matrix. In the case of this embodiment, the matrix B is suitable for realizing high sensitivity when the following two conditions are satisfied. (1) The ratio of the number 1 is large in all rows. (2) In the measurement, the matrix B, the vector S, and the vector C of the equation (1) are obtained. Therefore, in order to obtain the vector A, an inverse matrix of the matrix B needs to exist. That is, the matrix B needs to be a regular matrix.

As the regular matrix that satisfies the above two conditions, the Hadamard matrix and the orthogonal matrix having the M-sequence and the M-sequence shift as row vectors are optimal. The M sequence is a cyclic code sequence that uses a primitive polynomial ( ^m-th order polynomial on the Galois field GF (q) whose period is equal to q ^m−1 ) as a generator polynomial, and the period is expressed as m-order primitive polynomial. In this case, 2 ^{m + 1} −1.

For example, if the primitive polynomial is a fourth-order recurrence formula represented by a5 = a4 + a3 + a1 + a0, the period is 2 ⁵ −1 = 31. An M sequence generated by this primitive polynomial is shown in FIG. Further, FIG. 13B shows a matrix constituted by M sequence groups generated by sequentially shifting the arrangement positions of the elements in the M sequence. This matrix is set by the electron beam irradiation matrix setting unit 65 as a matrix B as an electron beam irradiation matrix. The electron beam irradiation matrix setting unit 65 may store the electron beam irradiation matrix determined in advance as described above, or the electron beam irradiation matrix may be set according to the number of elements required as described above. It may be calculated as follows.

FIG. 14 shows the state of each two-dimensional pattern when electron beam irradiation is performed in time series based on the matrix B as the electron beam irradiation matrix set as described above. The two-dimensional pattern shown in (A) shows a two-dimensional pattern irradiated with an electron beam based on the first row of the matrix B, and the two-dimensional pattern shown in (B) is based on the second row of the matrix B. The two-dimensional pattern irradiated with the electron beam is shown, and the two-dimensional pattern shown in (C) shows the two-dimensional pattern irradiated with the electron beam based on the 31st row of the matrix B. Thus, an electron microscope image can be measured with high S / N by irradiating a two-dimensional pattern 2 ^{m + 1} −1 times with an electron beam based on the electron beam irradiation matrix.

Specifically, as shown in FIG. 15, the projector control unit 61 causes the first to second ^{m + 1} −1 light patterns 13 to be emitted at predetermined time intervals based on the electron beam irradiation matrix. To control. As a result, the first to second ( ^{m + 1)} -1 electron beam arrays 14 are sequentially emitted from the MCP 11 and irradiated onto the sample 5.

  Hereinafter, a description will be given of a method in which the matrix calculation unit 66 calculates the vector A from Expression (1) when the matrix B is a matrix composed of M-sequence cyclic codes as shown in FIG. .

  First, in the matrix B, a matrix in which an element part having an element value of 0 is replaced with −1 (each row of this matrix is called a pn sequence) is called a matrix B ′. Can be represented.

  In the above equation, the matrix E ′ indicates a matrix in which all elements are 1. Substituting this equation (2) into equation (1) yields:

In Equation (3), in order to solve for the vector A, the transposed matrix B ′ ^T of the matrix B ′ is multiplied on both sides to obtain the following equation.

Here, each element of the matrix B ′ ^T B ′ corresponds to an autocorrelation function in the pn sequence, and each element b ′ _ij of the matrix B ′ ^T B ′ is expressed by the following equation.

On the other hand, in the matrix B ′ ^T E ′, since the number of 1 is one more than the number of −1 in the pn sequence, the following equation is obtained.

  Therefore, in the case of L >> 1, the following expression can be obtained based on Expression (5) and Expression (6).

  Here, the matrix E represents an L × L unit matrix. Based on the equations (7) and (4), the following equation is obtained.

From the above equation, it can be seen that by obtaining the matrix B ′ ^T , the vector A is obtained, and a two-dimensional electron microscope image can be obtained. Here, the matrix B ′ ^T can be easily obtained by transposing the element part having the element value of 0 in the matrix B set by the electron beam irradiation matrix setting unit 65 by transposing it with −1. It is.

  Finally, each block of the controller 17, in particular, the electron beam irradiation matrix setting unit 65 and the matrix calculation unit 66 may be configured by hardware logic, or may be realized by software using a CPU as follows. .

  That is, the controller 17 includes a central processing unit (CPU) that executes instructions of a control program that implements each function, a read only memory (ROM) that stores the program, a random access memory (RAM) that expands the program, A storage device (recording medium) such as a memory for storing programs and various data is provided. An object of the present invention is to provide a recording medium on which a program code (execution format program, intermediate code program, source program) of a control program of the controller 17 which is software for realizing the above-described functions is recorded in a computer-readable manner. This can also be achieved by supplying to the controller 17 and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  The controller 17 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Also, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

  The electron microscope system of the present invention can be suitably used for observing nanostructures of organic / bio-based samples, for which demand is increasing in recent years.

In the structure of the electron microscope system which concerns on one Embodiment of this invention, it is a block diagram which shows the functional block with which a controller is provided. It is a figure which shows schematic structure of the said electron microscope system. It is a perspective view of the principal part fracture | rupture in the microchannel of MCP used for the said irradiation apparatus. It is a perspective view of the principal part fracture | rupture of the said MCP. It is a graph which shows the relationship between the applied voltage of said MCP, and a gain. It is a perspective view which shows the state in which the electron beam array is produced | generated from the optical pattern in the said MCP and an electron lens beam part, and it is converged and projected. The electron beam array is focused, (a) is a perspective view of the state, (b) is a perspective view of the focused electron beam array on the sample, and (c) is a perspective view. It is a schematic front view which shows the interaction between each electron beam in the said focused electron beam array. An example for alleviating the interaction between each micro electron beam of the electron beam array is shown. (A) shows divided light beams which are formed by dividing a light pattern for generating the electron beam array and interpolate with each other. It is a top view which shows the example of a pattern, (b) is a top view which shows an electron beam array when the said each division | segmentation light pattern is match | combined. The grid-shaped electrostatic lens part for shaping the electron beam array from said MCP is shown, (a) is a principal part fracture perspective view of the said grid-shaped electrostatic lens part, (b) is the said grid-shaped electrostatic lens part. It is sectional drawing of a lens part. (A) is a schematic front view which shows the electron beam of this invention, (b) is a schematic front view which shows the conventional electron beam. In the electron beam irradiation method as a reference example, it is a figure which shows the example of the two-dimensional pattern irradiated with an electron beam in a time series. The figure which shows the electron beam irradiation matrix which shows the time series when the state which showed the matrix which shows a two-dimensional pattern by a vector, and all the pixels of a two-dimensional pattern are irradiated with an electron beam in order in the electron beam irradiation method as a reference example It is. (A) is a figure which shows the example of the M series produced | generated by the primitive polynomial, (b) is comprised by the M series group produced | generated by shifting the arrangement position of each element in M sequence in order. It is a figure which shows a matrix. It is a figure which shows the state of each two-dimensional pattern in case electron beam irradiation is performed in time series based on an electron beam irradiation matrix. It is a figure which shows the state from which an optical pattern is irradiated to MCP11 based on an electron beam irradiation matrix, and an electron beam array is radiate | emitted. It is a graph which shows the change of a general decrease over time in the minimum processing dimension of DRAM as a semiconductor element and a microprocessor. It is a graph which shows the relationship between the exposure wavelength and the resolution in X-ray exposure, EUV exposure, and electron beam exposure. The example of the exposure by the conventional electron beam is shown, (a) is sectional drawing, (b) is an expanded sectional view. Other examples of exposure with a conventional electron beam are shown, (a) is a cross-sectional view, (b) is an enlarged cross-sectional view, and (c) is an empty space on a Si substrate as a reticle, which is not possible with the other examples. It is a front view which shows the example of a hole.

Explanation of symbols

1 Vacuum chamber 2 Stage 3 Mechanical drive 4 Stage position monitor 5 Sample 7 Electron beam resist 8 Projector (light pattern generator)
9 Optical Lens 10 Photoelectric Film 11 MCP (Electronic Amplifier)
DESCRIPTION OF SYMBOLS 12 Electron beam lens part 13 Optical pattern 14 Electron beam array 15 Secondary electron detector 16 Grid-shaped electrostatic lens part 17 Controller 18 Display 19 Input part 51 Electron beam irradiation unit 52 Computer system 61 Projector control part (light pattern generation control means )
62 Electronic lens control unit 63 Detection signal receiving unit 64 Mechanical drive control unit 65 Electron beam irradiation matrix setting unit (pattern setting means)
66 Matrix operation unit (image generation means)
67 Image processing unit (image generating means)
68 Display control unit 69 Input control unit

Claims (12)

An electron beam irradiation apparatus comprising: an electron beam irradiation unit that irradiates a sample as an observation target with a two-dimensional pattern by an electron beam; and a secondary electron detector that detects secondary electrons emitted from the sample by the electron beam irradiation. An electron microscope control device for generating an electron microscope image of a sample by:
Pattern setting means for setting a two-dimensional pattern of an electron beam to be emitted from the electron beam irradiation unit in time series;
Image generation means for generating an electron microscope image of the sample based on the time-series two-dimensional pattern set by the pattern setting means and the time-series detection signal detected by the secondary electron detector. ,
The pattern setting means sets each of the time-series two-dimensional patterns so as to include the pixels irradiated with the electron beam among the pixels included in the two-dimensional pattern, and sets the number of all pixels included in the observation region, An electron microscope control apparatus characterized in that an equal number of two-dimensional patterns are set in time series so as to become two-dimensional patterns independent of each other.   The pattern setting means is set to include a plurality of pixels irradiated with an electron beam among at least one two-dimensional pattern among the two-dimensional patterns set in time series. An electron microscope control device. The pattern setting means sets a vector representing each two-dimensional pattern as a row, sets the matrix in the column direction along a time series, and sets a regular matrix as an electron beam irradiation matrix,
The image generation means performs a matrix operation based on the electron beam irradiation matrix and a vector representing a time-series detection signal detected by the secondary electron detector, thereby showing an electron microscope image of the sample. The electron microscope control apparatus according to claim 1, further comprising a matrix calculation unit that calculates a vector.   2. The electron microscope according to claim 1, wherein the pattern setting means sets the number of pixels irradiated with the electron beam to be larger than half of the total number of pixels among the pixels included in each two-dimensional pattern. Control device. The pattern setting means sets a vector representing each two-dimensional pattern as a row, sets the matrix in the column direction along a time series, and sets a regular matrix as an electron beam irradiation matrix,
The image generation means performs a matrix operation based on the electron beam irradiation matrix and a vector representing a time-series detection signal detected by the secondary electron detector, thereby showing an electron microscope image of the sample. It has a matrix calculation unit that calculates vectors,
5. The electron microscope control apparatus according to claim 4, wherein the electron beam irradiation matrix is a Hadamard matrix or a regular matrix having M-sequence and M-sequence shifts as row vectors.   The image generation means also takes into account the time-series noise signal superimposed on the detection signal output from the secondary electron detector when the electron beam irradiation based on each two-dimensional pattern is performed. The electron microscope control apparatus according to claim 1, wherein an electron microscope image is generated. The electron beam irradiation apparatus generates, as the electron beam irradiation unit, a light pattern generation unit for generating a two-dimensional light pattern, an electron beam array based on the incident light pattern, and the electron beam array An electron amplification unit for amplifying and emitting, and an electron beam lens unit for accelerating and focusing the electron beam array,
The light pattern generation control means for controlling emission of the light pattern by the light pattern generation section based on the time-series two-dimensional pattern set by the pattern setting means. Electron microscope control device. An electron beam irradiation apparatus comprising: an electron beam irradiation unit that irradiates a sample as an observation target with a two-dimensional pattern by an electron beam; and a secondary electron detector that detects secondary electrons emitted from the sample by the electron beam irradiation. An electron microscope control method for generating an electron microscope image of a sample by:
A pattern setting step for setting a two-dimensional pattern of an electron beam to be emitted from the electron beam irradiation unit in time series;
An image generation step for generating an electron microscope image of the sample based on the time-series two-dimensional pattern set by the pattern setting step and the time-series detection signal detected by the secondary electron detector; And
The pattern setting step sets each of the time-series two-dimensional patterns so as to include the pixels irradiated with the electron beam among the pixels included in the two-dimensional pattern, and the number of all pixels included in the observation region. And set the same number of two-dimensional patterns in time series so as to be two-dimensional patterns independent of each other,
Among the two-dimensional patterns set in time series, at least one two-dimensional pattern is set so as to include a plurality of pixels irradiated with an electron beam among pixels included in the two-dimensional pattern. Electron microscope control method.   The control program for functioning a computer as each means with which the electron microscope control apparatus of any one of Claims 1-7 is provided.   A computer-readable recording medium on which the control program according to claim 9 is recorded. An electron beam irradiation apparatus comprising: an electron beam irradiation unit that irradiates a sample as an observation target with a two-dimensional pattern by an electron beam; and a secondary electron detector that detects secondary electrons emitted from the sample by the electron beam irradiation. When,
An electron microscope system comprising: the electron microscope control device according to claim 1. An electron beam irradiation unit for irradiating a sample to be observed with a two-dimensional pattern by an electron beam;
An electron beam irradiation apparatus comprising: a secondary electron detector that detects secondary electrons emitted from a sample by irradiation with an electron beam.

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