JP2004304031A - Mask scanning lithography method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mask scanning lithography method by which a pattern can be formed with high dimensional accuracy without relying upon the kind of a character pattern nor other patterns existing in the periphery of the character pattern. <P>SOLUTION: In the mask scanning electron beam lithography method, the pattern is formed with high dimensional accuracy without relying upon the kind of the character pattern nor other patterns existing in the periphery of the character pattern by using shaped beams A, B, and C having different sizes to the peripheral section and inside of the character pattern and, in addition, correcting the doses of the shaped beams with sufficiently high spatial resolution by changing the doses at the time of scanning the character pattern by successively using the shaped beams A, B, and C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pattern writing technique using a charged particle beam or an electromagnetic wave beam, and more particularly to a mask scan writing method for writing a character pattern on a sample by beam scanning a character pattern.
[0002]
[Prior art]
In recent years, in a character projection type electron beam drawing apparatus, a so-called mask scan drawing method has been proposed in which a character pattern is scanned with a shaped beam instead of transferring the entire character pattern at once (for example, see Patent Document 1). reference). However, in this type of mask scan drawing, the dimensional accuracy is degraded due to the discontinuity of the position or irradiation amount at the connection between the character patterns, and furthermore, the distance between the scanned shaped beams in the character pattern is reduced. There has been a problem that the dimensional accuracy is deteriorated due to the shift of the scanning position and the discontinuity of the irradiation amount.
[0003]
In order to solve these problems, when the electron beam is scanned in a predetermined direction on the character mask, a part of the first scanning region of the electron beam is overlapped with the second scanning region to be scanned next. (For example, see Patent Document 2).
[0004]
On the other hand, a decrease in dimensional accuracy due to the so-called proximity effect depending on the pattern density is a problem in the mask scanning method. Representative examples of the proximity effect correction method include an irradiation amount correction method in which irradiation is performed by changing the irradiation amount according to the location of a pattern, and a GHOST method in which exposure is performed twice. There are various proposals for proximity effect correction when transferring large-area character patterns, but even with these methods, there are still the following problems, and the desired dimensional accuracy is achieved in mask-scan drawing. It turns out that you can't.
[0005]
One of the phenomena relates to the proximity effect caused by the character pattern itself and the proximity effect caused by the relationship between the proximity pattern and the peripheral pattern. In particular, a dimensional change in the vicinity of a connection portion between the character pattern and a peripheral pattern other than the character pattern has been a problem. In addition, there is a problem that the pattern is not formed to a desired size due to the influence of fogging due to the fogging effect which depends on the shape of the drawing pattern and the layout of the entire pattern and affects a wider range than the proximity effect. Further, in the stencil type EB mask which is usually used, the scattered electrons due to the reflected electrons from the lower edge portion of the Si beam at the pattern opening fall down on the substrate as stray light through the electron optical system. There was a problem that proper irradiation was hindered.
[0006]
Here, in order to explain a phenomenon considered to occur due to these factors, a character pattern is given to a resist when a photosensitive resist on a substrate to be drawn is irradiated with an electron beam, assuming lines and spaces. FIGS. 6A to 6C are schematic diagrams showing examples of the exposure intensity profile.
[0007]
6A and 6B show the influence of the proximity effect, and FIG. 6C shows the influence of fogging and stray light such as reflected electrons on the EB mask.
[0008]
FIG. 6 (a) shows a profile generated by applying energy to the resist with a spatial distribution of about 10 μm in the backscattered electrons on a normal glass mask substrate. At this time, at both ends of the line & space pattern, the gradient of the exposure intensity profile is relatively small. For example, a difference of about 20% of the exposure amount occurs in a range of about 10 μm.
[0009]
In such a case, as an example, the pattern size of the space portion of the positive resist is formed to be small because the exposure amount is reduced. In order to correct the dimensional deterioration, it is effective to change the exposure amount appropriately with a spatial resolution of about 1/10 of the blur radius. Therefore, it is necessary to perform drawing by controlling the irradiation amount with a beam size of about 1 μm. In the case of performing the auxiliary exposure as in the GHOST method, it is necessary to realize an exposure profile opposite to this profile, so that a spatial resolution is also required.
[0010]
FIG. 6B corresponds to the case where the substrate is made of Si, heavy metal, or the like, and the blur of the backscattered electrons can be about several μm to about 5 μm. In this case, the gradient of the exposure intensity profile at both ends of the pattern becomes steep, and the dimensional variation also increases. To correct this effect, it is necessary to correct the exposure amount with a sufficiently high spatial resolution, for example, a resolution of about 0.5 μm or 1 μm.
[0011]
FIG. 6C is an exposure intensity profile that can be generated when electrons fall from above the substrate due to scattering, reflected electrons, stray light, and fogging effects from the Si beam of the EB mask. In this case, compared with the proximity effect depending on the irradiation density of the electron beam (or the area density of the pattern to be drawn), scattered electrons and reflected electrons generated from the beam of the EB mask are more likely to be in the directionality of the pattern (pattern edge). (Difference depending on the direction of the linear density). For this reason, it is easy to give an anisotropic distribution to the exposure intensity profile, and it is assumed that the profile has a steeper gradient. Therefore, it is necessary to correct the exposure amount with a sufficiently high spatial resolution in accordance with the distribution of the exposure intensity profile.
[0012]
On the other hand, there has been proposed a method of predicting a dimensional change due to the proximity effect of the character pattern itself, and using a character mask formed by resizing in consideration of the dimensional change in advance. However, when a resized character pattern is used, dimensional fluctuation in the vicinity of a connection portion between the character pattern and a peripheral pattern that is not a character pattern, or when a larger area is transferred by connecting the same character pattern to each other. It is difficult to solve problems such as dimensional change near the connection.
[0013]
[Patent Document 1]
Patent No. 3034285
[0014]
[Patent Document 2]
JP 2001-217173 A
[0015]
[Problems to be solved by the invention]
As described above, conventionally, in the electron beam writing of the mask scan method using the character mask, there has been a problem that a dimensional change is caused by the type of the character pattern and other patterns located around the character pattern. In particular, a dimensional change in the vicinity of a connection portion between the character pattern and a peripheral pattern other than the character pattern has been a problem. Further, there is a problem that the pattern is not formed to a desired size due to the influence of fogging due to the fogging effect. Due to these factors, it has been difficult to form a pattern with high precision dimensions.
[0016]
The present invention has been made in consideration of the above circumstances, and has as its object the purpose of making a pattern of high-precision dimensions independent of the type of character pattern and other patterns located around the character pattern. It is an object of the present invention to provide a mask scan drawing method capable of forming a pattern.
[0017]
[Means for Solving the Problems]
(Constitution)
In order to solve the above problems, the present invention employs the following configuration.
[0018]
That is, the present invention irradiates a shaped beam of charged particles or electromagnetic waves onto a character mask having a character pattern, sequentially scans the shaped beam, forms an image of the projected beam of the character pattern on the sample surface, and forms the pattern. A mask scan writing method for writing, wherein at least a peripheral portion and an inside of the character pattern are changed in size or shape of the shaping beam, and an irradiation amount (an irradiation amount per unit area) of the shaping beam is changed. It is characterized by changing.
[0019]
Further, the present invention irradiates a shaped mask of charged particles or electromagnetic waves onto a character mask having a character pattern, sequentially scans the shaped beam, forms an irradiation projected beam of the character pattern on a sample surface, and forms the pattern. A mask scan drawing method for drawing, wherein a size or a shape and an irradiation amount (unit) of the shaping beam are determined according to an in-plane distribution and an intensity gradient of an exposure intensity generated by drawing the character pattern and a pattern in a peripheral portion of the pattern. (Irradiation amount per area) is partially changed on the character pattern.
[0020]
Here, preferred embodiments of the present invention include the following.
[0021]
(1) A plurality of types of character patterns are provided on a character mask, and one of the character patterns is selected according to a pattern to be drawn on a sample.
[0022]
(2) To reduce the size of the shaping beam and increase the irradiation amount in the peripheral portion with respect to the inside of the character pattern.
[0023]
(3) Changing the beam size in the direction parallel to the scanning direction during one-way scanning of the shaped beam.
[0024]
(4) With respect to the length of the side in each direction constituting the opening figure of the character pattern, based on the length of the component in the direction parallel to and perpendicular to the scanning direction, the length in the direction perpendicular to the direction of the longer side is determined. To change the beam size and correct the dose.
[0025]
(5) The character pattern includes means for generating drawing data for scanning in which the size or shape of a shaped beam is changed for each scanning area, and memory means for storing data, and the drawing data stored in the memory. Read out the scan drawing data specific to the character pattern selected from the above and perform the scan drawing.
[0026]
(6) The length of the side in each direction constituting the opening figure of the character pattern is determined based on the length of the component in the direction parallel and perpendicular to the scanning direction, and according to the directionality of the longer side. Generating scan drawing data so that the size or shape of the forming beam differs in the outer peripheral direction of the opening figure pattern of the character pattern.
[0027]
(7) The length of the side in each direction constituting the opening figure of the character pattern is determined based on the length of the component in the direction parallel to and perpendicular to the scanning direction, and according to the directionality of the longer side. Generating scan drawing data so that the size or shape of the shaped beam is locally changed in the character pattern plane.
[0028]
(8) The size (area) of the character pattern formed on the sample surface is approximately 20 μm square or more.
[0029]
(9) When sequentially scanning the character pattern on the character mask with the shaped beam, the beam is blanked while the beam moves from a predetermined position to the next position within the character pattern area.
[0030]
(10) Multiple drawing is performed partially or entirely on the character pattern on the character mask by irradiating the character beam with the forming beam repeatedly.
[0031]
(11) Performing multiple writing on a character pattern on a character mask by scanning a forming beam a plurality of times, partially or entirely.
[0032]
Further, the present invention provides a means for generating a charged beam or an electromagnetic wave beam, a means for blanking a beam, a character mask having a plurality of character patterns constituting a part of a circuit pattern to be drawn on a sample, A shaping aperture mask mounted with a plurality of shaping apertures for forming a beam for projecting a character mask, an aperture selecting deflecting means for selecting the shaping aperture, and shaping via the shaping aperture Scanning deflecting means for projecting and scanning the shaped beam onto a predetermined character pattern on the character mask, and sequentially scanning and irradiating the shaped beam onto the predetermined character pattern; Scan method that draws a pattern by imaging the image In the drawing apparatus, for each of the character patterns, a memory means for storing scan drawing data in which the size or shape of the shaped beam and the irradiation amount are changed, and a drawing means selected from the drawing data stored in the memory means. Means for reading specific scan drawing data according to the character pattern, controlling the irradiation amount of each shaping beam at the time of scanning by the blanking means based on the read data, and further controlling the size or shape of the shaping beam. Are sequentially selected by the shaping aperture selecting deflecting means to perform scan drawing.
[0033]
(Action)
According to the present invention, in a mask scanning type drawing method, when a forming beam is sequentially scanned and drawn on a character pattern, a forming beam having a different size or shape is applied to at least the peripheral portion and the inside of the character pattern. By using and changing the dose of each shaped beam, dose correction can be performed with sufficient spatial resolution. In addition, the size or shape of the shaping beam and the irradiation amount are partially changed on the character pattern in accordance with the in-plane distribution and the intensity gradient of the exposure intensity generated by drawing the character pattern and the pattern at the periphery of the pattern. Accordingly, the dose correction can be performed with a sufficient spatial resolution.
[0034]
Thereby, the influence of the dimensional change due to the proximity effect and the fogging due to the fogging effect can be effectively suppressed. Accordingly, it is possible to form a pattern with high precision dimensions without depending on the type of the character pattern or other patterns located around the character pattern.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
[0036]
(1st Embodiment)
FIG. 1 is a schematic configuration diagram showing an electron beam writing apparatus according to one embodiment of the present invention.
[0037]
In the figure, reference numeral 10 denotes an optical system (electron optical column), 30 denotes a sample chamber, 40 denotes a control circuit system, 50 denotes a control computer system, 60 denotes a measurement system, and 70 denotes a data processing system. First, the configurations of the optical system 10 and the sample chamber 30 will be described.
[0038]
In the figure, 11 is an electron gun, 12 is a beam limiting aperture, 13 is a condenser lens, 14 is a blanking electrode, 15 is a blanking slit, 16 is a shaping aperture selecting deflector, 17 is a shaping aperture mask, and 18 is a shaping aperture mask. Projection lens, 19 is a scan deflector, 20 is a character mask, 21 is a moving stage, 22 is a reduction lens, 23 is an objective deflector, 24 is an objective lens, 31 is a sample (substrate to be drawn), and 32 is a stage. I have.
[0039]
A part of the electron beam emitted from the electron gun 11 is cut by a beam limiting aperture 12, condensed by a condenser lens 13 and adjusted to a predetermined current density. The current density on the surface of sample 31 is up to 20 A / cm ² It is. The electron beam is controlled by a high-speed blanking control circuit 41 described later so that the electron beam passes or is cut off by the voltage of the blanking electrode 14 through the blanking slit 15. In this example, the beam is cut off when a voltage of 40 V is applied, and passes when the voltage is 0 V. The ON / OFF control of the electron beam is performed by the blanking electrode 14, and the irradiation amount at the time of writing is set by adjusting the ON / OFF time.
[0040]
The shaping aperture selecting deflector 16 is a deflector for selecting a predetermined aperture with respect to a shaping aperture mask 17 having openings of a plurality of sizes and shapes. The electron beam having passed through the blanking slit 15 is shaped into a beam having a predetermined size and shape by the shaping aperture selecting deflector 16. In the present embodiment, the plurality of openings described in the shaping aperture mask 17 are arranged in an area sufficiently smaller than the deflection area of the shaping aperture selecting deflector 16.
[0041]
The projection lens 18 (18a, 18b) projects the image of the shaping aperture selected by the shaping aperture selecting deflector 16 onto the character mask 20 via the scan deflector 19. The scan deflector 19 includes a deflector for scanning the selected aperture image on the character mask 20 and a deflector for changing the projection position of the aperture image on the character mask 20 (character pattern selection deflector). ). In the present embodiment, the scan range on the character mask 20 by the scan deflector 19 is about 300 μm, and the deflection area is about 1 mm □.
[0042]
The character mask 20 is mounted on the moving stage 21. When a character pattern located outside the deflection area 1 mm is selected, the moving stage 21 causes the corresponding character pattern to be approximately centered on the beam axis. It is positioned by a moving stage drive mechanism (not shown) so as to be positioned.
[0043]
The image of the character mask 20 is projected and formed on the sample 31 by the reduction lens 22 and the objective lens 24, and is scanned on the sample 31 by the objective deflector 23. Here, the reduction lens 22 and the objective lens 24 realize a low aberration optical system having a reduction ratio of 1/15 and an aberration of 30 nm in the main deflection region. The sample chamber 30 includes a stage 32 on which the sample 31 is mounted, and the stage 32 is driven by a stage drive circuit unit 45 described later.
[0044]
FIG. 2 shows a configuration of an aperture pattern used for the formed aperture mask 17 in the present embodiment. The formed aperture mask has six types of openings, including an aperture 175 used as a standard. The maximum beam size is about 2 μm on the sample surface and the reduction ratio is 1/15 from the device characteristics, especially the current density and the design restrictions of the low aberration optical system. Has an aperture size L of about 30 μm. The size of the aperture 171 is 7.5 μm × 15 μm in the vertical and horizontal directions in the figure, 172 is 15 μm × 15 μm, and 173 is 15 μm × 7.5 μm. 174 is 15 μm × 30 μm, 175 is 30 μm × 30 μm, and 176 is 30 μm × 15 μm.
[0045]
FIG. 3 shows three of nine character patterns located at the center of the mask as a part of the character mask 20 in the present embodiment. An aperture for variable shaping is arranged in the central pattern 200, and a square or triangular beam is formed depending on the degree of overlap with the image of the standard aperture 175 of the shaping aperture mask 17. In the case of drawing a pattern in which various character patterns cannot be used, the variable shaping drawing is executed by using the aperture for the variable shaping drawing.
[0046]
The character pattern 201 is a line and space in the y direction, and 202 is a line and space in the x direction, where the horizontal direction of the paper is the x direction and the vertical direction is the y direction. In addition to these, various patterns such as a contact hole pattern with serifs can be prepared. In drawing, a character pattern suitable for a circuit pattern to be drawn on the sample 31 is selected from various character patterns mounted on the character mask 20. The selection of the character pattern is performed by the scan deflector 19 (character pattern selection deflector) or the moving stage 21 as described above.
[0047]
Next, the control circuit system 40, control computer system 50, measurement system 60, and data processing system 70 will be described. After the design pattern data (CAD data) is input to the CAD system 71, the arithmetic processing unit 72 performs predetermined processing such as calculation of proximity effect correction and figure division. Then, the data is converted into special machine data by the data converter 73. The figure dividing process is performed by a figure dividing circuit in the arithmetic processing unit 72. That is, the design pattern data is sequentially developed and read, and the design pattern data is divided into a pattern portion for performing variable shaping drawing and a portion for performing mask scan drawing using a character pattern. The figure division data for variable shaping drawing is further divided into predetermined beam size units. At this time, the coordinate position, size, and irradiation time of each divided shot are set.
[0048]
Next, regarding the circuit pattern of the mask scan drawing portion, a code for each character pattern allocated to select a character pattern, a coordinate position of each character pattern, a beam size, a shape, and an irradiation at the time of scanning in the character pattern. Scan drawing data that defines time is set. Since this scan drawing data is different for each character pattern, by reading out the scan drawing data corresponding to the character pattern selected from the individual scan drawing data stored in advance in the memory means. Is set.
[0049]
These drawing conditions are prepared as data and temporarily stored in a buffer memory built in the data converter 73. Further, shaping deflection data is prepared so that a beam shot is shaped according to the shape and size of the graphic pattern in the variable shaping drawing portion and the mask scan drawing portion. The drawing data converted into the machine data is divided into strip-shaped frames as usual, and further divided into sub-deflection area units.
[0050]
Next, the machine data is transmitted to the control computer system 50, and each part of the control circuit system 40 is controlled by the control computer 51, the buffer memory 52, and the control circuit 53 based on the machine data. The control circuit system 40 includes a blanking control circuit 41 for driving the blanking electrode 14, a shaping aperture selecting deflection control circuit 42 for driving the shaping aperture selecting deflector 16, and a scan deflection control for driving the scan deflector 19. It comprises a circuit section 43, a character beam deflection control circuit section 44 for driving the objective deflector 24, and a stage drive circuit section 45 for driving the stage 32. The scan deflection control circuit 43 also has a function as a variable shaped beam size control circuit in variable shaped drawing.
[0051]
The measurement system 60 includes a laser interferometer 61 that measures the movement position of the stage 32 and a beam current measurement device 62 that measures the beam current on the sample 31. These measurement information is supplied to the computer 51. It has become.
[0052]
As described above, in the present apparatus configuration, based on the variable shaping drawing data and the scan drawing data generated from the design pattern data, the predetermined size and shape mounted on the shaping aperture mask 17 are used in the scan drawing. Select aperture. Then, the aperture image is projected onto a predetermined character pattern selected in the character mask, sequentially scanned, and the projected image is reduced and transferred to form an image on the sample surface to draw a pattern. . In particular, when sequentially scanning the inside of a predetermined character pattern, the beam is blanked while moving the beam as an aperture image from a predetermined position in the character pattern area to the next position.
[0053]
In this way, by sequentially scanning shots while blanking the beam, compared to a method of continuously scanning with the beam emitted, robustness against scan speed variation and irradiation dose variation is improved. Can be improved. For patterns other than the character pattern, variable shaping drawing is performed.
[0054]
Next, referring to FIGS. 4 and 5, taking the line and space pattern in the y direction as an example, changing the irradiation amount of the shaped electron beam to at least the peripheral part and the inside of the character pattern, and changing the size or (and) A description will be given of performing scan drawing using the shaped electron beams having different shapes. In both figures, a schematic diagram (a) showing the appearance of scanning, and a conceptual diagram (b) showing the relationship between the exposure intensity of the space obtained thereby and the distance from the left end of the pattern.
[0055]
FIG. 4 shows an aspect in which scanning is performed by blanking a beam while moving the beam in the scanning type drawing method. FIG. 5 shows an aspect of scanning according to the present embodiment. Note that the scan is started from the lower left of the character pattern, the scan direction is from left to right, and the mode is not folded. The size of the character pattern is 300 μm square, and line and space patterns having a line width of 0.6 μm are repeatedly arranged in this area.
[0056]
In the scan shown in FIG. 4A, a beam A having a fixed size and the same shape as the beam A is used. Each of the shaped beams A11, A12,..., A1n is scanned by repeating ON / OFF of the beam while sequentially performing blank / unblank control. Here, the beam A is a beam formed using the aperture 175 in FIG. 2 and has a designed size of 2 μm □. For each beam, a coordinate position in the character pattern and an irradiation amount (unblanking time) at the coordinate position are set, and the beam is blanked for a predetermined time while each beam moves to the next position. . However, in this figure, the irradiation dose of each beam is the same for the sake of explanation.
[0057]
When the beam is scanned with the same irradiation amount, the exposure amount at the four corners of the character pattern tends to be under, mainly due to the proximity effect. As shown in FIG. 4B, the exposure intensity decreases toward the left end of the pattern, the exposure intensity near the lower end (or upper end) decreases in the vertical direction of the pattern, and the dimension of the line & space in the character pattern. Will be distributed.
[0058]
Therefore, in order to at least reduce the non-uniformity of the line and space dimensions in the character pattern, a portion corresponding to the outer peripheral portion of the character pattern region within a range of a blur radius affected by the proximity effect has a sufficient spatial resolution. It is necessary to scan with the beam size and to correct the irradiation amount before drawing. For example, when drawing on a glass mask is assumed, it is appropriate to perform correction with a beam size of about 1 μm. In the case where correction is performed with a beam having a size of 2 μm as shown in this figure, sufficient accuracy cannot be obtained.
[0059]
Therefore, in this embodiment, as shown in FIG. 5A, in order to improve the non-uniformity of the exposure intensity, a beam B or a beam C having a small size is used for the periphery of the character pattern, and the inside of the character pattern is used. Scan writing is performed using a beam A having a large size. That is, with respect to the outer peripheral portion on the lower side, a beam C of 1 μm × 1 μm is used to scan up to C11, C12,... ,..., A1m, and then B13, B14 are scanned with a 1 μm × 2 μm beam. By repeating this, the periphery of the upper side is scanned with the beam C, thereby drawing the entire character pattern.
[0060]
The arrangement of the beam sizes and the manner of scanning are based on the total length of the sides in the y direction as compared with the total length of the sides in the x direction constituting the space pattern in the y direction which is the opening figure of the character pattern. The extension is overwhelmingly large, and the linear density is due to the large y-direction. The length of the side (edge component) in the y direction perpendicular to the scan direction (x direction) is longer than that in the x direction, and reflected electrons are generated from the edge in a direction parallel to the scan direction to reduce the exposure intensity distribution. Since it is formed anisotropically, the correction drawing is performed by changing the beam size in the x direction and changing the irradiation amount of each beam.
[0061]
As in the case of FIG. 4, from the prepared drawing data, each shaped beam is scanned by repeating ON / OFF of the beam while sequentially performing blank / unblank control, and the irradiation time of each beam is set appropriately. Is done. Specifically, the beam ON time is set to be longer at the left end and the upper and lower ends than in the center of the character pattern.
[0062]
It is expected that the exposure intensity distribution when drawing is performed in this way will be improved as shown in FIG. 5B. By changing the irradiation amount of the shaped electron beam to at least the peripheral part and the inside of the character pattern, and performing scan drawing using a shaped electron beam having a different size or shape, a spatial distribution and an intensity gradient were obtained. Exposure intensity can be improved.
[0063]
Also, when connecting the same character pattern to form a pattern in a larger drawing area, the irradiation size can be set with higher spatial resolution by reducing the beam size near the connection between the character patterns. Is desirable. Specifically, by using the scan data in which the beam size of the peripheral portion is changed as shown in FIG. 5A, the irradiation amount is adjusted in a minute area near the connection, thereby improving the connection failure such as disconnection. Becomes possible.
[0064]
In the above description, the line & space pattern is taken as an example. However, in order to set unique scan data for various character patterns, the character pattern is calculated by taking into account the proximity effect and the fogging effect by ordinary area density calculation. It is possible to calculate the exposure intensity profile based on the influence of itself and the peripheral pattern, and set the exposure intensity profile according to the in-plane distribution and the intensity gradient of the exposure intensity profile. As described with reference to FIG. 6, even when the exposure intensity is steep in the outer peripheral portion of the character pattern or when the character pattern has a local distribution, the intensity distribution is small enough to compensate the intensity and the distribution profile. By performing the irradiation amount correction using the beam size, a highly accurate pattern can be formed.
[0065]
As described above, according to the present embodiment, when the shaped beam is sequentially scanned and drawn on the character pattern, by changing the size and the irradiation amount of the shaped beam with respect to the peripheral portion and the inside of the character pattern, The dose correction can be performed with a sufficient spatial resolution. In addition, by partially changing the size and irradiation amount of the forming beam in accordance with the in-plane distribution and intensity gradient of the exposure intensity generated by the drawing of the character pattern and its peripheral pattern, the irradiation amount with sufficient spatial resolution is obtained. Correction can be performed. For this reason, it is possible to form a pattern with high-accuracy dimensions without depending on the type of character pattern or other patterns located around the character pattern.
[0066]
(Modification)
Note that the present invention is not limited to the contents described in the above embodiment. In the embodiment, the electron beam lithography apparatus using both the mask scanning method and the variable shaping method is used as an example. However, it is needless to say that the present invention can be applied to various mask scanning type apparatuses. PREVAIL (Projection Reduction Exposure with Variable Axis Immersion Lenses), SCALPEL (Scattering with Angle Correction, etc.) Is applicable to the present invention.
[0067]
In the embodiment, an aperture mask having a plurality of rectangular apertures is used to change the size of the shaping beam irradiated on the character pattern. Instead, two aperture masks having a rectangular aperture are used. Beams of various dimensions may be formed by optically overlapping one aperture. In this case, the configuration of the optical system becomes complicated, but the beam size and shape can be changed more finely.
[0068]
Further, the present invention can be applied not only to an electron beam but also to a drawing apparatus using a charged beam such as an ion beam, and further to a drawing apparatus using an electromagnetic wave beam such as an ultraviolet light, a laser beam, and an X-ray beam. Further, the present invention can also be implemented in an exposure apparatus for a semiconductor or a liquid crystal panel or the like, or a process manufacturing apparatus such as an ion implantation apparatus by making appropriate changes as needed.
[0069]
In the embodiment, a series of data processing is executed by the components on the drawing apparatus to occupy the drawing apparatus main body. However, this is not always necessary. For example, it is effective to prepare drawing machine data by preparing an external data processing system different from the drawing apparatus without inputting the design data to the CAD system of the apparatus. By inputting the drawing machine data stored outside to the control computer system of the drawing apparatus main body, there is an advantage that necessary machine data can be prepared without occupying the drawing apparatus main body.
[0070]
In addition, various modifications can be made without departing from the scope of the present invention.
[0071]
【The invention's effect】
As described above in detail, according to the present invention, in a mask scanning drawing method, when forming a character pattern by sequentially scanning a shaped beam and drawing, the in-plane distribution of the beam position and the exposure intensity on the character pattern and By changing the size or shape of the shaped beam and the irradiation amount according to the intensity gradient, etc., a pattern with high precision dimensions can be obtained without depending on the type of character pattern or other patterns located around the character pattern. Can be formed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an electron beam writing apparatus according to an embodiment of the present invention.
FIG. 2 is a plan view showing a configuration of a formed aperture mask used in the embodiment.
FIG. 3 is an exemplary plan view showing a configuration of a character mask used in the embodiment;
FIG. 4 is a diagram showing a scanning state and an exposure intensity distribution in a conventional method.
FIG. 5 is a view showing a scanning state and an exposure intensity distribution in the embodiment.
FIG. 6 is a diagram showing an example of an exposure intensity profile according to a conventional method.
[Explanation of symbols]
10 ... Electron optical column 11 ... Electron gun
12: Beam limiting aperture 13: Condenser lens
14 blanking electrode 15 blanking slit
16: Aperture selecting deflector 17: Molded aperture mask
18 Projection lens 19 Scan deflector
20: Character mask 21: Moving stage
22 ... reduction lens 23 ... objective deflector
24: Objective lens 30: Sample chamber
31 sample (substrate to be drawn) 32 stage
40: control circuit system 41: blanking control circuit unit
42: Deflection control circuit for selecting the forming aperture
43 ... Scan deflection control circuit section
44 ... Character beam deflection control circuit
45: Stage drive control circuit unit 50: Control computer system
51: Computer 52: Buffer memory
53: control circuit 60: measuring system
61: Laser interferometer 62: Beam current measuring device
70: Data processing system 71: CAD system
72: arithmetic processing unit 73: data converter

Claims (4)

A mask scanning method that irradiates a shaped beam of charged particles or electromagnetic waves onto a character mask having a character pattern, sequentially scans the shaped beam, and forms a pattern by irradiating the projected beam of the character pattern on the sample surface to draw a pattern. Drawing method,
A mask scan drawing method, wherein the size or shape of the shaping beam is changed and the irradiation amount of the shaping beam is changed with respect to at least a peripheral portion and an inside of the character pattern. 2. The mask scan drawing method according to claim 1, wherein the size of the shaping beam is reduced and the irradiation amount is increased in a peripheral portion with respect to the inside of the character pattern. A mask scanning method that irradiates a shaped beam of charged particles or electromagnetic waves onto a character mask having a character pattern, sequentially scans the shaped beam, and forms a pattern by irradiating the projected beam of the character pattern on the sample surface to draw a pattern. Drawing method,
In accordance with the in-plane distribution and the intensity gradient of the exposure intensity generated by drawing the character pattern and the pattern at the periphery of the pattern, the size or shape of the shaping beam and the irradiation amount are partially changed on the character pattern. A mask scan drawing method. 4. The mask scan drawing method according to claim 1, wherein a plurality of types of the character patterns are provided on the character mask, and one of the character patterns is selected according to a pattern to be drawn on the sample. .

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