JPH1154395A - Charged beam image drawing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve precision of image drawing, by uniformly irradiating the whole surface of a specified region of a specimen, with a light of a Z sensor using a light for specimen surface position detection. SOLUTION: In this image drawing method, after a specimen 21 is set on a stage 31, it is scanned in order to measure the height as far as the specimen surface in the peripheral part of a pattern region 51 or in the end portion of the specimen 21, and the position of the specimen 21 is moved. In a location other than the pattern region 51, the illumination light of a Z sensor is turned on, and the height as far as the specimen 21 surface is measured. While the Z sensor illumination light is ON, the stage 31 is so driven that the whole surface of the specimen 21 is scanned by the locus of a spot 61 of the Z sensor illumination light. When the locus reaches the drawing start point 53 of the first frame of the pattern region 51, image drawing is started by turning on electron beam irradiation, in order to draw a circuit pattern. In the state that the Z sensor is turned on, image drawing is performed also in the pattern region 51, successively to the peripheral region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged beam writing apparatus for writing a desired pattern on a sample surface, and more particularly, to detecting a shift in the beam axis direction of the sample surface by irradiation of non-photosensitive light. The present invention relates to a charged beam drawing apparatus having a function of performing correction.

[0002]

2. Description of the Related Art In the manufacture of a semiconductor device, a lithography technique for reducing and transferring various patterns formed on a mask onto a wafer by using light is used. Extremely high precision is required for a mask pattern used in this lithography technique, and an electron beam lithography apparatus is used to create the pattern. An electron beam drawing apparatus is also used for drawing a pattern directly on a wafer without using a mask.

An electron beam writing apparatus includes an electron gun for generating an electron beam, an electron optical system for guiding a beam emitted from the electron gun onto a sample, and an electron beam for scanning the entire surface of the sample with the electron beam. It consists of a stage system. Furthermore, a variable shaped beam type electron beam writing system uses a shaping deflector to shape the irradiated electron beam into a desired shape, and a highly accurate positioning of the shaped electron beam on the sample surface. Objective deflector.

The area which can be positioned by the objective deflector is
It is about several millimeters in order to suppress the aberration of the electron optical system. On the other hand, the size of a sample is, for example, about 200 mm for a silicon wafer, and about 150 mm square for a glass substrate used for a mask. Therefore, the sample has a stage capable of scanning the entire surface with the electron beam.

[0005] In this type of electron beam lithography system, the height of the surface of a sample to which an electron beam is guided may fluctuate due to a change in the surface shape due to the running accuracy of the stage or the difference between samples. Since the change in the height direction of the sample surface changes the length of the trajectory of the electron beam, the electron beam guided in the magnetic field rotates according to Fleming's left hand rule. In the variable shaped beam type electron beam writing apparatus, as shown in FIG. 9A, a pattern is formed by connecting the shapes of the electron beam formed at a predetermined position. When the shot is rotating, the pattern connection accuracy is deteriorated as shown in FIG.

Therefore, a Z sensor for measuring the displacement of the electron beam at the focal position on the sample surface, particularly in the direction along the trajectory of the electron beam, is provided to measure the fluctuation of the focal position during writing, The surface position is corrected. For the Z sensor, for example, a sample surface such as a wafer or a glass substrate on which a metal such as chromium is vapor-deposited has a good reflectivity, so that it can be easily and inexpensively configured, and furthermore, non-contact and highly accurate displacement measurement. Optical sensors that can be used have been used. An oblique incidence optical system has been employed so that a reflection surface can be formed on the sample surface so that the positional displacement of the sample surface drawn by the electron beam can always be measured.

In the production of a mask, a resist (photosensitive resin) applied on a glass substrate on which a metal film of chromium or the like is applied is irradiated with energy by electron beam drawing, thereby exposing the resist to a desired one. In order to obtain a pattern, since these resists almost transmit visible light used for a Z sensor or the like, it has been considered that there is no problem even if light is constantly applied during writing. Therefore, conventionally, after the sample is set, the Z sensor is always turned on to constantly measure the shape of the substrate surface.

However, when the present inventors repeated various experiments using this type of electron beam writing apparatus,
It has been found that an error occurs in the dimension of the drawn pattern due to the influence of the Z sensor. This is explained as follows.

The sensitivity of the electron beam resist used for electron beam lithography is increased so that it is exposed in a short time in order to shorten the time required for lithography. In addition, since the sensitivity also changes depending on the temperature, in actual use, the sample is baked uniformly at a predetermined set temperature before drawing in order to stabilize the sensitivity of the sample. At the focal position where the electron beam is applied to the glass substrate coated with the resist, the temperature may increase locally. This temperature rise is considered to return to room temperature instantaneously due to the effect of thermal radiation, considering that the shot size of the electron beam is several μm and the irradiation time is several milliseconds.

On the other hand, the visible light laser used for the Z sensor is almost completely transmitted through the resist.
It is impossible to pattern with the light of the sensor. However, with respect to laser light having a wavelength in the visible light range of about 500 to 800 nm used for the Z sensor, even when 90% or more of the light is transmitted, the remaining several percent of energy is absorbed by the resin constituting the resist. Is done. It is considered that the absorbed energy is not enough to give a change such as exposing the resist to light (cutting the side chain structure of the resin), and is therefore converted into heat.

Here, the Z sensor is, as shown in FIG.
In order to measure the position fluctuation of the sample surface at the drawing focal point, the laser light used is focused so as to form an elliptical spot of about several tens of μm on the reflection surface. It is considered that the energy per unit area increases due to the light being collected, and the temperature is locally increased by several tens of degrees. This temperature is sufficient to increase the sensitivity of the resist. Therefore, there is a possibility that the sensitivity of the resist is locally changed in a region irradiated with the laser beam from the Z sensor. This is because the sensitivity generally increases as the temperature rises. For this reason, a positive resist becomes larger than a desired pattern size.

[0012]

As described above, conventionally, in an electron beam lithography apparatus having a function of detecting the displacement of the sample surface in the beam axis direction by the Z sensor and correcting the position of the sample surface, the electron beam writing apparatus has a The laser beam irradiation locally raises the temperature of the resist, which causes a change in pattern line width (pattern dimensional error).

The above-mentioned influence becomes greater as the accuracy of the pattern is increased by shortening the wavelength of the exposure light source, using a phase shift mask, and reducing the transfer magnification of the mask in a recent electron beam drawing apparatus. Further, the above problem is not limited to the electron beam writing apparatus, but can be similarly applied to the ion beam writing apparatus.

The present invention has been made in view of the above circumstances, and has as its object to reduce the pattern line width associated with the use of a Z sensor utilizing light for detecting a sample surface position. An object of the present invention is to provide a charged beam writing apparatus capable of reducing fluctuations and improving writing accuracy.

[0015]

[Means for Solving the Problems]

(Structure) In order to solve the above problem, the present invention employs the following structure. That is, the present invention (claim 1)
A charged beam optical system for irradiating a charged beam on the surface of the sample coated with the resist and scanning the charged beam on the surface, and a direction orthogonal to an optical axis direction of the charged beam optical system for holding the sample and holding the sample. A movable stage, and irradiating a non-photosensitive light to the resist with a diameter smaller than the scanning range of the charged beam in the vicinity of the optical axis of the charged beam optical system on the sample surface and detecting the reflected light thereof Sample surface position detecting means for detecting the position of the sample surface in the optical axis direction, and correcting the sample surface to match the focal position of the charged beam based on the position information detected by the sample surface position detecting means. A sample surface position correcting means for performing the correction by the sample surface position correcting means, while scanning the charged beam and moving the stage to the resist applied to the sample surface. A charged beam writing apparatus for writing a desired pattern, wherein the stage is moved so that the non-photosensitive light scans the entire surface of the sample uniformly, in addition to the movement of the stage when writing the pattern. It is characterized by the following.

Further, according to the present invention (claim 2), the surface of the sample coated with the resist is irradiated with a charged beam,
A charged beam optical system for scanning a charged beam on the surface, a stage that holds the sample and is movable in a direction orthogonal to an optical axis direction of the charged beam optical system, and a diameter smaller than a scanning range of the charged beam. A sample for irradiating the resist with light insensitive to the resist in the vicinity of the optical axis of the charged beam optical system on the sample surface and detecting the reflected light to detect the position of the sample surface in the optical axis direction Surface position detecting means, and a sample surface position correcting means for correcting the sample surface to match the focal position of the charged beam based on the position information detected by the sample surface position detecting means. A charged beam writing apparatus for writing a desired pattern on a resist applied to a sample surface by scanning the charged beam and moving the stage while performing correction by means. In addition to the movement of the stage at the time of draw, the non-photosensitive light is characterized in that moving the stage to uniformly scan the desired area of the sample surface.

Further, according to the present invention (claim 3), the surface of the sample coated with the resist is irradiated with a charged beam,
A charged beam optical system for scanning a charged beam on the surface, an irradiation amount correcting means for controlling an irradiation energy amount per unit area of the charged beam on the sample surface, and the charged beam optical system for holding the sample and A stage movable in a direction orthogonal to the optical axis direction of the system; and a light non-photosensitive to the resist having a diameter smaller than the scanning range of the charged beam, and a light beam near the optical axis of the charged beam optical system on a sample surface. And a sample surface position detecting means for detecting the position of the sample surface in the beam axis direction by detecting the reflected light, and charging the sample surface based on the position information detected by the sample surface position detecting means. A sample surface position correcting means for correcting the position of the charged beam so as to match the focal position of the beam, and scanning the charged beam and the stage while performing correction by the sample surface position correcting means. What is claimed is: 1. A charged beam writing apparatus for writing a desired pattern on a resist applied to a surface of a sample by movement, wherein the irradiation amount correction unit irradiates the non-photosensitive light with an area corresponding to the irradiation of the light. It is characterized in that the irradiation energy of the charged beam is reduced by the energy.

Further, according to the present invention (claim 4), the surface of the sample coated with the resist is irradiated with a charged beam,
A charged beam optical system for scanning a charged beam on the surface, a stage that holds the sample and is movable in a direction perpendicular to the optical axis direction of the charged beam optical system, and a diameter smaller than the scanning range of the charged beam. A sample surface for irradiating the resist with light insensitive to the resist in the vicinity of the optical axis of the charged beam optical system on the sample surface and detecting the reflected light to detect the position of the sample surface in the beam axis direction A position detection unit, and a sample surface position correction unit that corrects the surface of the sample based on the position information detected by the sample surface position detection unit so that the sample surface is aligned with the focal position of the charged beam. A charged beam writing apparatus for writing a desired pattern on a resist applied to a sample surface by scanning the charged beam and moving the stage while performing correction by the sample surface. The 置検 detecting means to reduce the amount of energy irradiated on the resist, characterized by intermittently performing the light irradiation of the light-insensitive due to the sample surface position detecting means.

Further, according to the present invention (claim 5), the surface of the sample coated with the resist is irradiated with a charged beam,
A charged beam optical system for scanning a charged beam on the surface, a stage that holds the sample and is movable in a direction perpendicular to the optical axis direction of the charged beam optical system, and a diameter smaller than the scanning range of the charged beam. A sample surface for irradiating the resist with light insensitive to the resist in the vicinity of the optical axis of the charged beam optical system on the sample surface and detecting the reflected light to detect the position of the sample surface in the beam axis direction Position detecting means, a memory for storing position information obtained by the sample surface position detecting means, and a sample for correcting the surface of the sample based on the position information stored in the memory so that the surface of the sample matches the focal position of the charged beam. Surface position correcting means, and while performing correction by the sample surface position correcting means, a desired pattern is formed on the resist applied to the sample surface by the scanning of the charged beam and the movement of the stage. A writing beam writing apparatus for writing, wherein, before writing, the stage is moved so that the non-photosensitive light from the sample surface position detection means uniformly scans the entire surface of the sample surface, and the surface of the sample with respect to the stage position is moved. The position in the beam axis direction is stored in the memory, and at the time of writing, the irradiation of the non-photosensitive light by the sample surface position detecting means is stopped, and the correction by the sample surface position correcting means is performed based on the information stored in the memory. It is characterized by performing.

Here, preferred embodiments of the present invention include the following. (1) The sample surface position correcting means moves the stage in the beam axis direction (Z direction). (2) The sample surface position correcting means changes the excitation condition of the electron lens for imaging the electron beam on the sample surface. (3) Irradiate non-photosensitive light uniformly only on the pattern formation area, not on the entire surface of the sample. (4) Irradiate non-photosensitive light uniformly only to the area where high pattern accuracy is required in the pattern formation area.

(Operation) According to the present invention (claim 1), the stage is moved so that the non-photosensitive light for detecting the position of the sample surface uniformly scans the entire surface of the sample surface. The amount of energy from the non-photosensitive light incident on the sample becomes uniform over the entire sample surface. For this reason, even if there is an increase in sensitivity due to non-photosensitive light with respect to the resist applied on the sample surface, the sensitivity is not a local increase but an overall increase in the sensitivity. Variations in pattern line width can be eliminated over the entire surface of the sample.

Further, according to the present invention (claim 2), the stage is moved so that the non-photosensitive light uniformly scans an arbitrary area on the sample surface. Therefore, the amount of energy from the light having the same intensity becomes uniform, and the fluctuation of the pattern line width in the region can be eliminated.

Further, according to the present invention (claim 3), the irradiation energy of the charged beam is reduced by the energy corresponding to the irradiation of the non-photosensitive light in the area to which the non-photosensitive light is irradiated. The sensitivity increase of the resist due to the photosensitive light can be corrected by the change in the irradiation amount of the charged beam,
Variations in pattern line width can be suppressed.

According to the present invention (claim 4), non-photosensitive light for detecting the sample surface position is not continuously irradiated, but is operated intermittently, for example, in synchronization with the speed of the stage. By doing so, it is possible to reduce the amount of energy incident on the resist while having the conventional position measurement function. Then, a change in the pattern dimension accompanying this can be reduced, and the in-plane uniformity of the pattern dimension can be improved.

According to the present invention (claim 5), before writing, the position of the sample surface in the beam axis direction is detected by the sample surface position detecting means and stored in the memory, and the non-photosensitive light is emitted from the sample. By moving the stage so as to uniformly irradiate the entire surface of the surface, the amount of energy from the non-photosensitive light over the entire surface of the sample becomes uniform over the entire sample surface. It is no longer necessary to irradiate the pattern line width, so that the pattern line width does not change over the entire surface of the sample.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. (First Embodiment) FIGS. 1 and 2 are for explaining a schematic configuration of an electron beam writing apparatus according to a first embodiment of the present invention. FIG. 1 is a perspective view, and FIG. is there.

The electron beam writing apparatus includes an electron optical system 10 for generating an electron beam and writing a predetermined minute area with high accuracy, and an electron optical system for writing an entire surface of the sample 21. A stage system 30 housed in a sample chamber 20 capable of keeping a space including a stage 31 scanable with respect to the optical center of the sample 10 in a vacuum state;
And a Z sensor system 40 for measuring the distance to the sample surface provided at a position symmetrical with respect to the optical center of the electron optical system 10 in the wall of the sample chamber 20 at a position opposite to.

The electron optical system 10 includes an electron gun unit 11 for generating an electron beam, a condenser lens unit 12 for condensing the generated electron beam, and a rectangle for shaping the condensed electron beam. First forming aperture 13 of
A projection lens unit 14 for projecting a rectangular shaped electron beam; a second shaping aperture unit 15 provided below the projection lens unit 14 for shaping the electron beam into a desired shape; A shaping deflecting electrode section 16 disposed in the lens section 14 for changing the activation of the electron beam and illuminating the electron beam at a predetermined position of the shaping aperture 15 to obtain an electron beam of a desired shape; Lens unit 17 for reducing the size of the electron beam, and objective deflection electrode unit 18 for positioning the electron beam at a predetermined position on the sample surface.
It is composed of

The sample 21 is, for example, a glass substrate of about 5 to 9 inches square if the electron beam lithography apparatus is a mask lithography apparatus, or a φ6 to 12 inches wafer if the electron beam lithography apparatus is a direct wafer lithography apparatus. Although not shown, the surface of the sample 21 is finished so that the surface becomes a mirror surface in the case of a wafer, and a process such that a metal thin film layer of chromium or the like is provided by vapor deposition or the like in the case of glass. Therefore, both of them exhibit high reflectance to visible light. Further, a resist layer coated with a resist exhibiting photosensitivity to an electron beam is provided on these mirror surfaces. Note that this resist shows little sensitivity to visible light and is largely transmitted, and as a result, the reflectance for visible light is maintained.

The stage system 30 includes a holding mechanism (not shown) capable of detachably holding the sample 21 and a stage 31 capable of driving the entire surface of the sample 21 over the optical center of the electron optical system 10. A reflection mirror 32 for reflecting a laser beam for measuring the position of the stage 31, and a laser fixed to the side wall of the sample chamber 20 for measuring the position of the stage 31 with high accuracy using the reflection mirror 32 And an interferometer 33.

The Z sensor system 40 includes a projection illumination optical system 41 for projecting a visible light laser of about 500 to 900 nm onto the surface of the sample 21, and a detection system for condensing and detecting the light reflected by the sample 21. And an optical system 42,
These are fixed to the upper wall of the sample chamber 20. In order to measure the surface shape of the sample 21 held on the stage 31 at the optical center of the electron optical system 10, light from the illumination optical system 41 is arranged to illuminate the center of the electron optical system 10. I have.

Next, a drawing method according to the present embodiment will be described with reference to FIG. In the writing method according to the present embodiment, after setting the sample 21 on the stage 31, the height to the sample surface is measured at the periphery of the pattern area 51 for writing a circuit pattern or at the end of the sample 21. For this purpose, the stage 31 is scanned to move the position of the sample 21. Here, the pattern area 51 is divided into a plurality of strip-shaped areas (frames), and each frame is drawn by one continuous movement of the stage and scanning of the electron beam.

Subsequently, in a place other than the pattern area 51, after the illumination light of the Z sensor is turned on and the height is measured to the surface of the sample 21, the spot of the Z sensor illumination light is kept while the Z sensor illumination light is on. The stage 31 is driven so that the locus of 61 scans the entire surface of the sample 21. That is, after the stage 31 is continuously moved in the X direction by the length of the sample 21, the stage 31 is stepped in the Y direction by the width of the spot 61 of the Z sensor illumination light, and further continuously moved in the direction opposite to the X direction. By repeating this, the locus of the illumination light spot 61 scans the entire surface of the sample 21.

While the stage 31 is being moved as described above, when the drawing start point 53 of the first frame of the pattern area 51 is reached, the electron beam irradiation for drawing a circuit pattern is turned on to start drawing. Start. The pattern area 51 is also drawn following the peripheral area with the Z sensor turned on. In this manner, even after drawing of the pattern area 51 is completed and the irradiation of the electron beam is turned off, the stage 31 is driven so that the locus 61 of the spot of the Z sensor illumination light scans the remaining portion. .

As described above, in this embodiment, the energy from the Z sensor illumination light is made uniform over the entire surface of the sample 21, that is, the spot 61 of the Z sensor illumination light scans the entire surface of the sample. By moving the stage 31, the change in pattern dimension due to a local change in sensitivity of the resist can be reduced. Therefore, it is possible to reduce the fluctuation of the pattern line width due to the use of the Z sensor using light for detecting the sample surface position,
It is possible to improve the drawing accuracy.

In this embodiment, the drawing is started when the Z sensor spot light 61 reaches the position of the drawing start point 53 of the frame. However, when the spot light 61 reaches the center of the frame in the Y direction, that is, in the normal case, The drawing may be started when the center of the optical axis of the electron optical system comes to the center in the Y direction at the end of the frame in the X direction in the same manner as the drawing of FIG. In addition, spot light 6
Since the stage 31 is moved so as to scan the entire surface of the sample in step 1, even if the scanning width of the electron beam is widened, it is not possible to improve the drawing throughput. Therefore, the scanning width of the electron beam is the same as the width of the spot light 61. It may be.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
FIG. 9 is a schematic diagram for explaining a drawing procedure in the embodiment.

In the sample 21 such as a glass mask, a defect inspection apparatus for inspecting a pattern defect and an exposure apparatus for transferring a pattern onto a wafer are provided around a pattern area 51 where a main circuit pattern is drawn. Marks 55 used for alignment, and identification marks 57 such as IDs and bar codes for identifying each pattern for managing a mask may be arranged. Regarding the marks 55 used for the alignment, there is no problem in the alignment of the mask if the position of the center of gravity of the pattern does not change even if the size changes. Further, since the identification mark 57 such as a bar code does not require the precision such as the pattern dimension, it is not necessary to draw the entire mask with high precision.

Even when the resist is applied to the entire surface of the glass substrate, the uniformity of the energy from the illumination light of the Z sensor is important only in the pattern region 51 where uniformity of the pattern dimensions is required. Therefore, as shown in FIG. 4, the movement of the stage 31 for scanning the Z sensor illumination light is set or selected in accordance with the pattern area 51 so as not to scan the entire mask, so that the uniformity of the pattern dimension is improved. By drawing only the necessary pattern area 51 with high accuracy, the drawing can be performed without deteriorating the pattern dimensional accuracy of the area where accuracy is required, thereby improving the throughput.

FIG. 5 shows this state in more detail. One frame of the pattern area 51 is an area to be drawn by one movement of the stage in the X direction and scanning of the electron beam in the Y direction. The spot light 61 does not irradiate the pattern area 51 but irradiates only the pattern area 51.
At this time, since the width of the spot light 61 is smaller by about one digit than the scanning width of the electron beam, one stage movement cannot cover an entire frame. Then, after continuously moving the stage in the X direction, the stage is moved in the Y direction by the width of the spot light 61 in the Y direction, and the stage is further moved by -X.
Move continuously in the direction. By repeating this, the entire one frame is scanned by the spot light 61. The same applies to other frames, whereby the entire pattern area 51 is scanned.

Pattern drawing by electron beam irradiation is 1
Since the stage is performed by one continuous movement of the stage for one frame, it starts when the spot light 61 reaches the end of the frame or reaches a position passing through the center of the frame.

In normal electron beam writing, the stage 31
Is moved in the X direction, and one frame of the pattern area 51 is drawn by electron beam irradiation. At this time, the spot light 6 for position detection is located near the center of the beam scanning range.
1 is irradiated to detect the position of the sample surface in the Z direction, and this is fed back to the stage 31 to correct the height position of the stage. In this case, the spot light 61 is irradiated only in the vicinity of the center of the frame, and the pattern line width in this portion varies.

Therefore, in this embodiment, the stage 31 is continuously moved in the X direction and stepwise moved in the Y direction, separately from the irradiation of the spot light near the center of the frame at the time of electron beam writing, so that the entire surface of the frame is exposed to the spot light. Scan 61. Thus, the amount of energy from the spot light 61 becomes uniform over the entire surface of the frame, and the amount of energy from the spot light 61 becomes uniform over the entire surface of the pattern region 51, so that the line width variation of the pattern can be eliminated.

Also, as shown in FIG. 6, the stage 31 is moved so that the spot light 61 is uniformly irradiated only in the region 52 of the frame where the highest pattern accuracy is required, as shown in FIG. You may do it.

As described above, according to the present embodiment, not the entire sample but only the pattern region 51 or the pattern region 5
By moving the stage 31 so that the spot light 61 is uniformly irradiated only in the region 52 where particularly high accuracy is required, the pattern dimensional accuracy of a necessary portion can be maintained. In this case, the spot light may be scanned over a part of the sample instead of scanning the entire surface of the sample, so that the throughput can be improved.

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention.
FIG. 9 is a schematic diagram for explaining a drawing method according to the embodiment.

The drawing method according to the present embodiment utilizes the fact that the sensitivity of the resist changes depending on the irradiation amount of the electron beam. For the pattern area 52 where the dimensional uniformity is required, an increase in sensitivity due to the Z sensor illumination light 61 is estimated in advance by a computer (not shown). When the pattern area 52 is drawn with an electron beam, the dimensional change due to the energy from the Z sensor is corrected by changing the irradiation amount of the electron beam only in the area 52.

That is, the sensitivity of the resist increases in the irradiation area 53 of the spot light 61 due to the continuous movement of the stage during electron beam writing, but in the irradiation area 54 of the spot light in the area 52, only the energy corresponding to the irradiation of the spot light Reduce the amount of electron beam irradiation. As a result, in-pattern uniformity of dimensions in the pattern region 52 is ensured. In this case, if the correction of the electron beam irradiation amount is performed in all of the spot light irradiation regions 53, the time required for the correction calculation becomes enormous. Can be reduced.

(Fourth Embodiment) In the drawing method according to the fourth embodiment of the present invention, the illumination light of the Z sensor, which has been continuously illuminated conventionally, is replaced with a Z sensor illumination light control circuit (not shown) or the like. As a result, the Z sensor illumination light is emitted intermittently. Accordingly, the amount of total energy incident on the resist can be reduced, and the dimensional change of the pattern can be reduced.

This is because, for example, when the moving speed of the stage 31 is slow, the interval between the incidences of the illumination light is increased, and when the moving speed of the stage 31 is fast, the interval between the incidence of the illumination light is shortened. , It is possible to reduce the amount of incident energy from the Z sensor as a whole while keeping the amount of energy incident on the resist per unit area the same.

(Fifth Embodiment) FIG. 8 shows a fifth embodiment of the present invention.
FIG. 2 is a block diagram showing a main configuration of an electron beam writing apparatus according to the embodiment.

In the present embodiment, the surface shape of the sample 21 is read by the Z sensor 81 before writing, and is stored in the memory 82 by scanning the entire surface of the sample 21 to be drawn beforehand on the stage 31 after holding it on the stage 31 in advance. Remember. Thereafter, even when the Z sensor 81 is turned off, the surface shape of the sample 21 can be recognized by referring to the memory 82 without turning on the Z sensor 81. Therefore, during writing, it is possible to prevent the Z sensor illumination light from illuminating the resist, and it is possible to eliminate a pattern dimension change due to a synergistic effect with the electron beam.

The position of the sample surface in the Z direction during the writing is corrected based on the sample surface position information stored in the memory 82.
The stage controller 83 may drive the stage 31 in the Z direction. Also, instead of driving the stage 31,
The excitation condition of the reduction lens unit 17 may be changed by the lens control unit 84.

The present invention is not limited to the above embodiments. The configuration of the electron beam optical system is not limited to those shown in FIGS. 1 and 2 and can be changed as appropriate according to the specifications. In the embodiment, the electron beam lithography apparatus has been described as an example. However, the present invention can be applied to an ion beam lithography apparatus. In addition, various modifications can be made without departing from the spirit of the present invention.

[0055]

As described above in detail, according to the present invention, light irradiation by the Z sensor using light for detecting the position of the sample surface is performed uniformly over the entire surface of the sample or in a specific region, or intermittently. By performing or reducing the irradiation amount of the charged beam by the energy of light irradiation, the variation of the pattern line width due to the use of the Z sensor can be reduced, and the drawing accuracy can be improved. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an electron beam writing apparatus according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a schematic configuration of an electron beam writing apparatus according to the first embodiment.

FIG. 3 is a schematic diagram for explaining a drawing procedure in the first embodiment.

FIG. 4 is a schematic diagram for explaining a drawing procedure according to the second embodiment.

FIG. 5 is a schematic diagram for explaining a drawing procedure in the second embodiment in more detail.

FIG. 6 is a schematic diagram for explaining a drawing procedure in the second embodiment in more detail.

FIG. 7 is a schematic diagram for explaining a drawing procedure in the third embodiment.

FIG. 8 is a block diagram showing a main configuration of an electron beam writing apparatus according to a fifth embodiment.

FIG. 9 is an explanatory diagram of a pattern drawn by a variable shaped beam type electron beam drawing apparatus.

FIG. 10 is an explanatory diagram showing a relationship between a focus of an electron beam and a spot size of a Z sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Electron optical system 11 ... Electron gun part 12 ... Condenser lens part 13 ... First shaping aperture part 14 ... Projection lens part 15 ... Second shaping aperture part 16 ... Shaping deflection electrode part 17 ... Reduction lens part 18 ... Objective deflection electrode Part 20: sample chamber 21: sample 30: stage system 31: stage 32: reflection mirror 33: laser interferometer 40: Z sensor system 41: projection illumination optical system 42: detection optical system

Claims (5)

[Claims] 1. A charged beam optical system for irradiating a charged beam on a surface of a sample coated with a resist and scanning the charged beam on the surface, and an optical axis of the charged beam optical system for holding the sample and holding the sample. A stage movable in a direction orthogonal to the direction, and light insensitive to the resist with a smaller diameter than the scanning range of the charged beam is irradiated on the surface of the sample near the optical axis of the charged beam optical system, A sample surface position detecting means for detecting the position of the sample surface in the optical axis direction by detecting the reflected light; and a focal position of the charged beam based on the position information detected by the sample surface position detecting means. And a sample surface position correcting means for correcting so as to match with the sample surface position correction means, while performing the correction by the sample surface position correcting means, is applied to the sample surface by scanning the charged beam and moving the stage. A charged beam writing apparatus for writing a desired pattern on a resist, wherein the stage is moved so that the non-photosensitive light scans the entire surface of the sample uniformly, in addition to movement of the stage when writing the pattern. A charged beam drawing apparatus characterized by being moved. 2. A charged beam optical system for irradiating a charged beam on a surface of a sample coated with a resist and scanning the charged beam on the surface, and an optical axis of the charged beam optical system holding the sample and holding the sample. A stage movable in a direction orthogonal to the direction, and light insensitive to the resist with a smaller diameter than the scanning range of the charged beam is irradiated on the surface of the sample near the optical axis of the charged beam optical system, A sample surface position detecting means for detecting the position of the sample surface in the optical axis direction by detecting the reflected light; and a focal position of the charged beam based on the position information detected by the sample surface position detecting means. And a sample surface position correcting means for correcting so as to match with the sample surface position correction means, while performing the correction by the sample surface position correcting means, is applied to the sample surface by scanning the charged beam and moving the stage. A charged beam writing apparatus that writes a desired pattern on a resist, in addition to moving the stage when writing the pattern, the non-photosensitive light uniformly scans an arbitrary area on the sample surface. A charged beam drawing apparatus characterized by moving a stage. 3. A charged beam optical system for irradiating a charged beam on a surface of a sample coated with a resist and scanning the charged beam on the surface, and an irradiation energy per unit area of the charged beam on the sample surface. Irradiation amount correcting means for controlling the amount, a stage that holds the sample and is movable in a direction perpendicular to the optical axis direction of the charged beam optical system, and a resist having a smaller diameter than the scanning range of the charged beam. A sample surface position detecting means for irradiating a non-photosensitive light on the surface of the sample near the optical axis of the charged beam optical system, and detecting the reflected light to detect the position of the sample surface in the beam axis direction. And sample surface position correcting means for correcting the surface of the sample to match the focal position of the charged beam based on the position information detected by the sample surface position detecting means, A charged beam writing apparatus for writing a desired pattern on a resist applied to a sample surface by scanning the charged beam and moving the stage while performing correction by a position correcting unit, wherein the irradiation amount correcting unit A charged beam drawing apparatus characterized in that the irradiation energy of a charged beam is reduced by an amount of energy corresponding to irradiation of photosensitive light in an area irradiated with the photosensitive light. 4. A charged beam optical system for irradiating a charged beam on a surface of a sample coated with a resist and scanning the charged beam on the surface, and an optical axis direction of the charged beam optical system for holding the sample and holding the sample. A stage movable in a direction orthogonal to the direction, and light insensitive to the resist with a smaller diameter than the scanning range of the charged beam is irradiated on the surface of the sample near the optical axis of the charged beam optical system. A sample surface position detecting means for detecting a reflected light to detect a position of the sample surface in the beam axis direction, and a focal position of the charged beam based on the position information detected by the sample surface position detecting means. And a sample surface position correcting means for performing correction so that the charged beam is applied to the sample surface by scanning the charged beam and moving the stage while performing correction by the sample surface position correcting means. What is claimed is: 1. A charged beam writing apparatus for writing a desired pattern on a resist, comprising: irradiating a non-photosensitive light with the sample surface position detecting means in order to reduce an amount of energy applied to the resist by the sample surface position detecting means. A charged beam drawing apparatus, wherein the charged beam writing is performed intermittently. 5. A charged beam optical system for irradiating a charged beam on a surface of a sample coated with a resist and scanning the charged beam on the surface, and an optical axis direction of the charged beam optical system for holding the sample and holding the sample. A stage movable in a direction orthogonal to the direction, and light insensitive to the resist with a smaller diameter than the scanning range of the charged beam is irradiated on the surface of the sample near the optical axis of the charged beam optical system. A sample surface position detector for detecting the reflected light to detect the position of the sample surface in the beam axis direction, a memory for storing position information obtained by the sample surface position detector, and a memory for storing the position information. Sample surface position correcting means for correcting the sample surface to match the focal position of the charged beam based on the obtained position information, and performing the correction by the sample surface position correcting means, A charged beam writing apparatus for writing a desired pattern on a resist applied to a sample surface by scanning and moving the stage, wherein a non-photosensitive light by a sample surface position detecting unit uniformly covers the entire surface of the sample surface before writing. While moving the stage so as to scan, the position of the sample surface in the beam axis direction with respect to the stage position is stored in the memory, at the time of drawing, the irradiation of non-photosensitive light by the sample surface position detection means is stopped, A charged beam drawing apparatus, wherein the correction by the sample surface position correcting means is performed based on information stored in the memory.