JP2001035769A - Pattern formation and charged particle beam exposure system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance positional accuracy of pattern exposure by accurately correcting a beam drift, while preventing reduction in the throughput. SOLUTION: A fluorescence 211, issued from an fluorescent substance film on a substrate 202 irradiated with an electron beam 203 based on one-irradiation position design data, is reflected by a inflecting mirror 212, guided to an imaging optical system 213, and then imaged on an image pick-up element 214. On the basis of an image signal S output from the element 214, a beam position computing means 215 finds an actually measured value De of the irradiation position of the electron beam 203, and finds a shift of the actually measured value De from a single irradiation position design data as a beam drift amount ΔD. A deflection position computing means 208 corrects for the beam drift amount ΔD, to compute a deflected position data Dd of the beam 203 corresponding to the next irradiation position design data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pattern forming method and a charged particle beam exposure apparatus.

[0002]

2. Description of the Related Art A charged particle beam exposure apparatus, particularly an electron beam exposure apparatus, has been widely used as a pattern forming means for a semiconductor integrated circuit or a photomask.

FIG. 6 is a perspective view showing a schematic configuration of a conventional electron beam exposure apparatus, and shows a deflection control system of an electron beam and a drive system of a wafer stage. In FIG. 6, a part of the electron beam deflection control system is schematically illustrated.

As shown in FIG. 6, a substrate 2 to be exposed is mounted on a wafer stage, specifically, an XY stage 1 movable in the X and Y directions, and a peripheral edge of the XY stage 1 is provided. An origin mark 3 is provided on an area of the portion where the substrate 2 to be exposed is not placed. The origin mark 3 is composed of, for example, a cross-shaped step, and a cross point of the origin mark 3 is a stage origin 3a.

When an electron gun 4 (not shown) provided above the XY stage 1 irradiates the substrate 2 with the electron beam 4, the electron gun 4 is moved backward from the region of the substrate 2 to which the electron beam 4 is irradiated. Reflected electrons 5 such as scattered electrons and secondary electrons are generated, and bounce back in the direction opposite to the irradiation direction of the electron beam 4. In order to detect the backscattered electrons 5, a backscattered electron detector 6 is provided directly above the XY stage 1.

[0006] An aperture and an electron lens (not shown) are provided between the XY stage 1 and the electron gun. The electron beam 4 is shaped into a predetermined shape by an aperture and an electron lens, and is imaged on the substrate 2 to be exposed by the electron lens.

In the vicinity of the XY stage 1 in the X direction,
A first laser interferometer 7a for measuring the position of the XY stage 1 in the X direction, that is, the X coordinate, is disposed, and is located near the XY stage 1 in the Y direction and in the Y direction of the XY stage 1. A second laser interferometer 7b for measuring the position, that is, the Y coordinate, is provided.

In the conventional electron beam exposure apparatus, the design data of the irradiation position of the electron beam 4 (hereinafter referred to as irradiation position design data) prepared in advance to draw a predetermined pattern on the substrate 2 to be exposed. Are stored in the drawing data storage means 8.

The irradiation position design data stored in the drawing data storage means 8 and the first laser interferometer 7a and the second
The deflection position calculation means 9 calculates the deflection amount of the electron beam 4, that is, deflection position data, based on the position data (the X coordinate and the Y coordinate) of the XY stage 1 measured by the laser interferometer 7b. . Further, based on the deflection position data calculated by the deflection position calculation means 9, the deflection voltage generation means 10 applies a predetermined deflection voltage to the first deflection electrode plate 11a provided above the XY stage 1 and the second deflection electrode. The voltage is applied between the electrode plates 11b to deflect the electron beam 4. Thereby, the electron beam 4 is irradiated on the substrate 2 according to the irradiation position design data, and a predetermined pattern is drawn on the substrate 2.

By the way, a charged particle beam such as an electron beam can be easily deflected by an electric or magnetic field, while a charged particle beam is easily affected by disturbance.
A phenomenon occurs in which the trajectory of the charged particle beam emitted from the electron gun toward the material to be exposed fluctuates, and the irradiation position of the charged particle beam on the material to be exposed deviates from the irradiation position design data. This phenomenon is called beam drift, and is a main factor that degrades the position accuracy of pattern exposure.

Hereinafter, the beam drift will be described with reference to FIG.

As shown in FIG. 6, after the reflected electrons 5 bounce in the direction opposite to the direction of irradiation of the electron beam 4, they are captured by the first deflection electrode plate 11a or the second deflection electrode plate 11b. At this time, if the potential of the first deflecting electrode plate 11a is higher than the potential of the second deflecting electrode plate 11b, the reflected electrons 5 are deflected in the direction of the first deflecting electrode plate 11a. It is captured by the electrode plate 11a. On the other hand, the components of the electron optical system of the electron beam exposure apparatus, in particular, the surfaces of the first deflection electrode plate 11a or the second deflection electrode plate 11b, which are close to the electron beam 4, are irradiated with the electron beam 4. Since the generated contamination (contaminant) containing carbon as a main component is adhered, electrons captured by a component such as the first deflection electrode plate 11a stay on the surface of the component. As a result, the components such as the first deflection electrode plate 11a are charged, so that the position shift of the electron beam 4, that is, a beam drift occurs.

The cause of the beam drift is as follows.
In addition to the charging of the deflection electrode plate, charging of an aperture or the like not shown in FIG. 6 is assumed. In particular, when the resist film is irradiated with a charged particle beam, a solvent remaining inside the resist film or a contamination such as a volatile substance generated when the resist film is exposed to light adheres to the aperture or the like. As the irradiation time of the charged particle beam becomes longer, the deviation amount of the irradiation position of the charged particle beam from the irradiation position design data, that is, the beam drift amount increases.

In order to suppress the deterioration of the positional accuracy of pattern exposure due to the beam drift, in the conventional electron beam exposure method, beam drift correction using an origin mark, that is, origin correction is performed during pattern writing.

Hereinafter, the procedure of origin correction will be described with reference to FIG. (Procedure 1) Before irradiating the substrate 2 with the electron beam 4, the XY stage 1 is moved so that the origin mark 3 is directly below the electron beam 4, that is, the electron gun (not shown). (Procedure 2) The electron beam 4 is scanned with respect to the origin mark 3, and the reflected electrons 5 generated by the scanning are detected by the reflected electron detector 6, and based on the signal waveform of the reflected electrons 5, the stage origin 3a is set. The intensity of the deflection voltage required to deflect the electron beam 4 was obtained, and the intensity of the deflection voltage was measured by the first laser interferometer 7a and the second laser interferometer 7b. The position of the stage origin 8a is obtained based on the position data of the XY stage 1. (Procedure 3) After moving the XY stage 1 to a predetermined exposure start position, the substrate 2 to be exposed is irradiated with the electron beam 4 to draw a pattern. At this time, every time the irradiation time of the electron beam 4 reaches a predetermined time, pattern writing is interrupted, and (procedure 1) and (procedure 2) are performed. When a beam drift occurs during pattern writing, the position of the stage origin 8a obtained by (Procedure 2) fluctuates apparently according to the beam drift amount. Therefore, after the pattern writing is restarted, the amount of change in the position of the stage origin 8a is regarded as the amount of beam drift, and the amount of beam drift is corrected by deflection control of the electron beam 4 or drive control of the XY stage 1. Then, the substrate 2 to be exposed is irradiated with the electron beam 4.

[0016]

However, in the above-described electron beam exposure method, it is necessary to interrupt the pattern writing every time a predetermined time elapses and move the wafer stage to obtain the position of the stage origin. Therefore, a decrease in the throughput of the pattern exposure is inevitable. In particular, when the time interval for performing the origin correction is shortened in order to improve the positional accuracy of the pattern exposure, the throughput of the pattern exposure is greatly reduced.

Also, during pattern writing, in other words, during the period from one origin correction to the next origin correction, the amount of change in the position of the stage origin, that is, the amount of beam drift, cannot be measured. When the beam drift occurs due to the above, appropriate beam drift correction cannot be performed, so that the positional accuracy of the pattern exposure is greatly reduced.

Incidentally, the charged state of the components of the electron optical system which causes beam drift greatly changes depending on the pattern writing area density. For example, when a fine pattern is sparsely drawn using a variable shaping exposure method or a partial batch exposure method, the amount of charge reaching a material to be exposed in a certain period of time is small, so that the components of the electron optical system are charged. Since it becomes smaller, the beam drift amount also becomes smaller. On the other hand, when a large area pattern is densely drawn by using the variable shaping exposure method or the partial batch exposure method, the amount of charge reaching the material to be exposed in a certain time is large, so that the components of the electron optical system are charged. Becomes larger, so that the beam drift amount also becomes larger. That is, the time interval for performing the origin correction is semi-empirically determined based on the relationship between the pattern writing area density of the pattern and the beam drift amount.

In a reduction projection type charged particle beam exposure apparatus proposed in recent years, a charged particle beam is shaped into a predetermined pattern, and the shaped charged particle beam is moved with respect to an origin mark. Since the position of the stage origin is determined by scanning, the accuracy of measurement of the position of the stage origin, that is, the accuracy of origin correction is reduced, and the position accuracy of pattern exposure is reduced.

In view of the foregoing, it is an object of the present invention to improve the positional accuracy of pattern exposure in charged particle beam exposure so that beam drift correction can be performed accurately while preventing a decrease in throughput.

[0021]

In order to achieve the above object, a first pattern forming method according to the present invention comprises a resist film forming step of forming a resist film by applying a resist material on a substrate; Pattern exposure is performed by irradiating a charged particle beam onto a resist film based on irradiation position design data, which is design data of a charged particle beam irradiation position, which is prepared in advance for drawing a predetermined pattern on the resist film. And a pattern forming method including a pattern forming step of developing a pattern-exposed resist film to form a resist pattern, between the resist film forming step and the exposing step, a charged particle beam The method further comprises a fluorescent material film forming step of forming a fluorescent material film by applying a fluorescent material that generates fluorescent light by irradiation on the resist film, and the exposing step includes: Capturing the fluorescence generated from the fluorescent material film by the irradiation of the electron particle beam as an image, processing the image to determine the measured value of the irradiation position of the charged particle beam on the resist film, and irradiating the measured value of the irradiation position The method includes a step of obtaining a deviation amount from the position design data as a beam drift amount, and a step of correcting the beam drift amount.

According to the first pattern forming method, a fluorescent material film that generates fluorescence by irradiation with a charged particle beam is formed in the fluorescent material film forming step, and the fluorescent material film is formed by irradiation of the charged particle beam in the exposure step. After capturing the fluorescence generated from as an image, processing the image,
The irradiation position actual value of the charged particle beam in the resist film is obtained, and the deviation amount from the irradiation position design data of the irradiation position actual value is obtained as a beam drift amount. Thereafter, one irradiation position is corrected to correct the beam drift amount. The beam drift amount obtained in the irradiation of the charged particle beam based on the design data is corrected, and the irradiation of the charged particle beam based on the next irradiation position design data can be performed.
Therefore, beam drift correction can be performed each time the charged particle beam is irradiated without interrupting the pattern drawing and moving the wafer stage, thereby improving the positional accuracy of pattern exposure while preventing a decrease in throughput. it can.

In the first pattern forming method, it is preferable that the resist material has no sensitivity to the fluorescent light generated from the fluorescent material film.

By doing so, the situation where the resist film is exposed to fluorescence can be avoided, and the resist film can be exposed only to the charged particle beam, so that the shape accuracy and dimensional accuracy of the pattern drawn on the resist film can be reduced. improves.

In the first pattern forming method, the resist material is preferably made soluble in an alkaline solution by irradiation with a charged particle beam, and the fluorescent material is preferably water-soluble.

In this way, the removal of the fluorescent material film and the development of the resist film can be simultaneously performed using the alkaline solution, so that the process can be simplified.

A second pattern forming method according to the present invention comprises:
A resist film forming step of applying a resist material on a substrate to form a resist film, and a charged particle beam prepared for drawing a predetermined pattern on the resist film with respect to the resist film; Pattern formation including an exposure step of performing pattern exposure by irradiating based on irradiation position design data which is design data of a beam irradiation position, and a pattern forming step of developing a resist film subjected to pattern exposure to form a resist pattern On the premise of the method, the resist material has a material that generates fluorescence by irradiation with a charged particle beam, and the exposure step includes a step of capturing the fluorescence generated from the resist film by irradiation with the charged particle beam as an image, and Processing to obtain the measured value of the irradiation position of the charged particle beam on the resist film; and setting the irradiation position of the measured value of the irradiation position. And a step of determining the amount of deviation from the data as a beam drift amount, and a step of correcting the beam drift amount.

According to the second pattern forming method, the resist material has a material that generates fluorescent light by irradiation with a charged particle beam, and in the exposure step, the fluorescent light generated from the resist film by the irradiation of the charged particle beam is imaged. After that, the image is processed to obtain a measured value of the irradiation position of the charged particle beam on the resist film, and a deviation amount from the irradiation position design data of the measured irradiation position value as a beam drift amount. In order to correct the beam drift amount, it is possible to correct the beam drift amount obtained in the irradiation of the charged particle beam based on one irradiation position design data and perform the irradiation of the charged particle beam based on the next irradiation position design data it can. Therefore, beam drift correction can be performed each time the charged particle beam is irradiated without interrupting the pattern drawing and moving the wafer stage, thereby improving the positional accuracy of pattern exposure while preventing a decrease in throughput. it can.

In the second pattern forming method, it is preferable that the resist material has no sensitivity to the fluorescence generated from the resist film.

By doing so, it is possible to avoid the situation where the resist film is exposed to the fluorescent light and to expose the resist film to only the charged particle beam, so that the pattern accuracy and dimensional accuracy of the pattern drawn on the resist film are reduced. improves.

The charged particle beam exposure apparatus according to the present invention comprises:
A pattern exposure is performed by irradiating a charged particle beam onto a substrate based on irradiation position design data which is design data of an irradiation position of the charged particle beam, which is prepared in advance for drawing a predetermined pattern on the substrate. Assuming a charged particle beam exposure apparatus, image input means for capturing an electromagnetic wave generated from the substrate by irradiation of the charged particle beam as an image,
By processing the image, a beam position calculating means for calculating an irradiation position actual value of the charged particle beam on the substrate, and a comparison calculating means for calculating a deviation amount from the irradiation position design data of the irradiation position actual value as a beam drift amount, Beam drift correction means for correcting the beam drift amount.

According to the charged particle beam exposure apparatus of the present invention, the electromagnetic wave generated from the substrate by the irradiation of the charged particle beam is captured as an image by the image input means, and the image is processed by the beam position calculating means to perform the charged particle irradiation. In order to obtain the actual value of the irradiation position of the beam and to obtain the amount of deviation of the actual value of the irradiation position from the irradiation position design data as the amount of beam drift by the comparison calculation means, and then to correct the amount of beam drift by the beam drift correction means ,
The beam drift amount obtained in the irradiation of the charged particle beam based on one irradiation position design data is corrected, and the irradiation of the charged particle beam based on the next irradiation position design data can be performed. Therefore, beam drift correction can be performed each time the charged particle beam is irradiated without interrupting the pattern drawing and moving the wafer stage, thereby improving the positional accuracy of pattern exposure while preventing a decrease in throughput. it can.

In the charged particle beam exposure apparatus according to the present invention, the charged particle beam is shaped into a predetermined shape, and the beam position calculating means includes means for processing an image to create image processing data; Based on the shape, by predicting the intensity distribution of the electromagnetic wave generated from the substrate by the irradiation of the charged particle beam, or by comparing the intensity distribution and the image processing data with the means stored in advance, the irradiation position actual measurement value It is preferable to have means for determining

With this configuration, even when the charged particle beam is formed into a predetermined shape, the actual measurement value of the irradiation position, that is, the beam drift amount can be accurately obtained.
Beam drift correction can be performed accurately.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a pattern forming method according to a first embodiment will be described with reference to FIGS.
This will be described with reference to FIG.

First, in a resist film forming step shown in FIG. 1A, a resist material which becomes soluble in an alkaline solution by irradiation with an electron beam is applied on a substrate 101 to form a resist film 102. It is assumed that the substrate 101 is mounted on a wafer stage, for example, an XY stage (not shown).

Next, in a fluorescent material film forming step shown in FIG. 1B, a fluorescent material which generates fluorescence by electron beam irradiation is applied on the resist film 102, and the fluorescent material film 1 is formed.
03 and the fluorescent material film 103 is dried.

In the fluorescent material film forming step, for example, zinc sulfide to which copper or aluminum is added is used as the fluorescent material. In this case, since the fluorescent material is soluble in the acidic solution, the fluorescent material film 103 can be formed by spin-coating the acidic solution in which the fluorescent material is dissolved on the substrate 101 on which the resist film 102 is formed.
In addition, by adding a water-soluble polymer material such as polyvinyl alcohol to the acidic solution in which the fluorescent material is dissolved, the applicability of the acidic solution can be improved.

Next, in the exposure step shown in FIG. 1C, the resist film 102 is irradiated with the electron beam 104 through the fluorescent material film 103 based on the irradiation position design data prepared in advance, and the pattern is formed. Perform exposure.

The feature of the exposure step in the pattern forming method according to the first embodiment is that an image input step of taking in a fluorescent light 105 generated from the fluorescent material film 103 by irradiation of the electron beam 104 as an image by an image pickup device or the like, The image captured in the process is processed by a computer or the like, and the electron beam 104 on the resist film 102 is
A beam position calculating step of calculating an actual irradiation position measured value, a comparison operation step of obtaining a deviation amount of the irradiation position measured value obtained in the beam position calculating step from the irradiation position design data, that is, a beam drift amount, and a comparison operation step. A beam drift correction step of correcting the obtained beam drift amount by deflection control of the electron beam 104, drive control of the wafer stage, or the like.

That is, in the first embodiment, after calculating the beam drift amount in the irradiation of the electron beam 104 based on one irradiation position design data, the beam drift amount is corrected, and the next irradiation position design data is corrected. Of the electron beam 104 based on the

Next, as shown in FIG. 1D, after the fluorescent material film 103 is removed using an acidic solution, the resist film 102 is developed using an alkaline solution. As shown in d), a resist pattern 106 consisting of an unexposed portion of the resist film 102 is obtained.

According to the first embodiment, the fluorescent material film 103 which generates fluorescence by irradiation with the electron beam 104 is formed in the fluorescent material film forming step, and the fluorescent material film 103 is irradiated by the electron beam 104 in the exposure step. After capturing the fluorescence 105 generated from the laser beam as an image, the image is processed and the electron beam 10 on the resist film 102 is processed.
4 and the deviation of the measured irradiation position from the irradiation position design data is determined as a beam drift amount. Thereafter, in order to correct the beam drift amount, an electron based on one irradiation position design data is used. Beam 104
Is corrected in the irradiation of the electron beam 104, and the electron beam 104 based on the next irradiation position design data is corrected.
Irradiation can be performed. Therefore, beam drift correction can be performed each time the electron beam 104 is irradiated without interrupting pattern writing and moving the wafer stage, thereby improving pattern exposure position accuracy while preventing a decrease in throughput. it can.

Although the electron beam 104 is used as the charged particle beam in the first embodiment, another charged particle beam may be used instead.

In the first embodiment, the resist material forming the resist film 102 is a fluorescent material film 103.
It is preferable not to have sensitivity to the fluorescence 105 generated from. By doing so, the situation where the resist film 102 is exposed to the fluorescent light 105 is avoided, and the resist film 10
Since 2 can be exposed only to the electron beam 104, the pattern accuracy and dimensional accuracy of the pattern drawn on the resist film 102 are improved.

In the first embodiment, the resist material forming the resist film 102 becomes soluble in an alkaline solution by irradiation with an electron beam, and the fluorescent material forming the fluorescent material film 103 is water-soluble. Is preferred. By doing so, the removal of the fluorescent material film 103 and the development processing of the resist film 102 can be performed simultaneously using an alkaline solution, so that the process can be simplified.

In the first embodiment, an inorganic material is used as the fluorescent material constituting the fluorescent material film 103, but an organic polymer material may be used instead. In this case, a base resin that is conventionally used as a base resin of a resist material and generates fluorescence by irradiation with an electron beam by a method of adding a predetermined substituent to a resin such as cresol novolak that generates fluorescence by irradiation of ultraviolet rays, or the like. Can be molecularly designed. That is, since a resist material that generates fluorescence upon irradiation with an electron beam can be formed, the step of forming the fluorescent material film 103 is not required by forming the resist film 102 made of the resist material. it can.

(Second Embodiment) Hereinafter, a charged particle beam exposure apparatus according to a second embodiment, specifically, a spot beam type electron beam exposure apparatus will be described with reference to FIG.

As shown in FIG. 2, a substrate 202 to be exposed is mounted on a wafer stage, for example, an XY stage 201 movable in the X and Y directions. An electron beam 203 emitted from an electron gun (not shown) provided above the XY stage 201 is irradiated on an exposed substrate 202 by an electron lens (not shown) provided between the XY stage 201 and the electron gun. It is imaged. Note that a resist film (not shown) and a fluorescent material film (not shown) that emits fluorescence when irradiated with the electron beam 203 are formed on the substrate 202 to be exposed.

When a voltage is applied to the blanking electrode 204 provided between the XY stage 201 and the electron gun,
The electron beam 203 is blocked by a blanking aperture 205 provided between the XY stage 201 and the blanking electrode 204. Thereby, the electron beam 2
03 can be applied to the substrate 202 for a predetermined time.

In the vicinity of the XY stage 201 in the X direction, a first laser interferometer for measuring the position of the XY stage 201 in the X direction, that is, the X coordinate, is arranged. Near the direction, the position of the XY stage 201 in the Y direction,
That is, the second laser interferometer for measuring the Y coordinate is arranged. Note that in FIG. 2, the first and second
Laser interferometer 206 together with the laser interferometer 206
As shown.

In the electron beam exposure apparatus according to the second embodiment, the irradiation position design data D of the electron beam 203, which is prepared in advance for drawing a predetermined pattern on the substrate 202 to be exposed, is stored in a drawing data storage. It is stored in the means 207.

Based on the irradiation position design data D stored in the drawing data storage means 207 and the position data L of the XY stage 201 measured by the laser interferometer 206 (the X and Y coordinates described above), deflection is performed. Position calculation means 20
8 calculates the deflection amount of the electron beam 203, that is, deflection position data Dd. Further, based on the deflection position data Dd calculated by the deflection position calculation means 208, the deflection voltage generation means 209 outputs a predetermined deflection voltage Vd to the XY stage 20.
The electron beam 4 is deflected by applying a voltage to a deflection electrode 210 provided above the electron beam 1. After the irradiation of the electron beam 203 based on one irradiation position design data is completed, the blanking electrode 204 and the blanking aperture 205 are used until the irradiation of the electron beam 203 based on the next irradiation position design data is started. The electron beam 203 is cut off.

The electron beam exposure apparatus according to the second embodiment is characterized in that the substrate 2 to be exposed is irradiated with the electron beam 203.
Image input means for capturing the electromagnetic waves generated from the image 02 as an image, beam position calculation means for processing the image captured by the image input means to obtain an actual measurement value of the irradiation position of the electron beam 203 on the substrate 202 to be exposed, and beam position calculation Means for calculating a deviation amount of the measured irradiation position of the electron beam 203 from the irradiation position design data, that is, a beam drift amount, and a beam drift amount obtained by the comparison operation means.
And a beam drift correction means for correcting by deflection control of the XY stage 201 or drive control of the XY stage 201.

That is, when the electron beam exposure apparatus according to the second embodiment is used, the beam drift amount in the irradiation of the electron beam 203 based on one irradiation position design data is obtained, and the beam drift amount is corrected. The irradiation of the electron beam 203 based on the next irradiation position design data can be performed.

The electromagnetic waves captured as an image by the image input means include, for example, the substrate 202 to be exposed.
X-rays generated from the main body or fluorescent light generated from a fluorescent material film (not shown) on the substrate 202 to be exposed are assumed.

Hereinafter, the case where the fluorescence generated from the fluorescent material film on the substrate 202 to be exposed is taken in as an image by the image input means and the amount of beam drift obtained by the comparison operation means is corrected by the deflection control of the electron beam 203 will be described. An example will be specifically described with reference to FIG.

The fluorescent light 211 generated from the fluorescent material film on the substrate to be exposed 202 by the irradiation of the electron beam 203 based on one irradiation position design data is provided directly above the substrate to be exposed 202 and has a smooth surface. After being reflected by the light 212, the light is guided to the imaging optical system 213, and thereafter, is imaged by the image sensor 214. Thereby, the fluorescence 21
1 is captured as an image by the image sensor 214.

That is, in the second embodiment, the image input means comprises the reflecting mirror 212, the imaging optical system 213, and the image sensor 214, but the configuration of the image input means is not limited to this.

An opening 212a for passing the electron beam 203 is provided at the center of the reflecting mirror 212. Further, in order to prevent the reflected electrons generated from the substrate 202 to be exposed by the irradiation of the electron beam 203 from adhering to the surface of the reflecting mirror 212 and charging the reflecting mirror 212,
Aluminum is deposited on the surface of the reflecting mirror 212.

Next, based on the image signal S output from the image sensor 214, the beam position calculating means 215 obtains the position where the fluorescent light 211 is generated on the substrate 202 to be exposed, that is, the actual irradiation position De of the electron beam 203. After that, the comparison operation unit 216 calculates the irradiation position measured value De calculated by the beam position calculation unit 215 and the deflection position calculation unit 208.
By comparing the calculated deflection position data Dd with the deflection position data Dd, the deviation amount from the actual irradiation position design data, ie, the beam drift amount ΔD, is obtained.
After that, the deflection position calculating means 208 executes the comparing operation means 21.
6, the beam drift amount ΔD calculated by
The deflection position data Dd of the electron beam 203 corresponding to the next irradiation position design data is calculated.

Next, based on the deflection position data Dd in which the beam drift amount ΔD has been corrected, the deflection voltage generation means 209
After applying a predetermined deflection voltage Vd to the deflection electrode 210,
The voltage of the blanking electrode 204 is turned off, and the irradiation of the electron beam 203 based on the next irradiation position design data is performed. Thereby, beam drift correction is performed by controlling the deflection of the electron beam 203.

That is, in the second embodiment, the beam drift correction means comprises the deflection position calculation means 208, the deflection voltage generation means 209 and the deflection electrode 210, but the configuration of the beam drift correction means is limited to this. Not something.

According to the second embodiment, the electron beam 20
3, an image input means for taking in an electromagnetic wave generated from the substrate 202 to be exposed as an image, a beam position calculating means 215 for processing the image to obtain an irradiation position actual value De of the electron beam 203, and an irradiation position actual value A comparison calculating means 216 for obtaining a deviation amount from the irradiation position design data of De as a beam drift amount ΔD;
And D is used to correct the electron beam 203 based on one irradiation position design data.
The beam drift amount ΔD obtained in the irradiation of the electron beam is corrected, and the electron beam 20 based on the next irradiation position design data is corrected.
3 irradiations can be performed. Therefore, beam drift correction can be performed each time the electron beam 203 is irradiated without interrupting the pattern drawing and moving the wafer stage, thereby improving the positional accuracy of pattern exposure while preventing a decrease in throughput. it can.

Although the electron beam 203 is used as the charged particle beam in the second embodiment, another charged particle beam may be used instead.

In the second embodiment, the reflecting mirror 2
12. Fluorescent light 211 generated from the fluorescent material film on the substrate 202 to be exposed is captured as an image by the image input means including the imaging optical system 213 and the image pickup device 214. By means, X-rays or the like generated from the substrate 202 to be exposed may be captured as an image.

(Modification of Second Embodiment) Hereinafter, a charged particle beam exposure apparatus according to a modification of the second embodiment, specifically, a spot beam type electron beam exposure apparatus will be described with reference to FIG. explain. In the modification of the second embodiment, the same members as those of the second embodiment shown in FIG.

The difference between the electron beam exposure apparatus according to the modification of the second embodiment and the second embodiment is that
In other words, beam drift correction is performed by drive control of the XY stage 201 instead of the deflection control of FIG.

Specifically, as shown in FIG. 3, after the comparison operation means 216 obtains the beam drift amount ΔD in the irradiation of the electron beam 203 based on one irradiation position design data, the comparison operation means 216 determines the beam drift amount ΔD and the beam drift amount ΔD. , Laser interferometer 2
Based on the position data L of the XY stage 201 measured in step 06, the stage driving means 217 moves the XY stage 201 to correct the beam drift amount ΔD, and then turns off the voltage of the blanking electrode 204. The electron beam 203 based on the next irradiation position design data.
Irradiation is performed. Thereby, the XY stage 201
, Beam drift correction is performed.

That is, in the modification of the second embodiment, the beam drift correction means comprises the XY stage 201 and the stage driving means 217, but the configuration of the beam drift correction means is not limited to this.

As described above, according to the modified example of the second embodiment, the deflection position calculation means 208 in the second embodiment is provided by the beam drift correction means comprising the XY stage 201 and the stage driving means 217. ,
Since the same function as that of the beam drift correction unit including the deflection voltage generation unit 209 and the deflection electrode 210 is realized, the same effect as that of the second embodiment can be obtained.

(Third Embodiment) Hereinafter, a charged particle beam exposure apparatus according to a third embodiment, specifically, a reduced projection type or partial batch type electron beam exposure apparatus will be described with reference to FIG. . Note that in the third embodiment,
The same members as those in the second embodiment shown in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

The electron beam exposure apparatus according to the third embodiment is different from the second embodiment in that the electron beam 203 is formed into a predetermined shot shape, and the beam position calculating means 215 is used instead. Image input means (reflecting mirror 21
2. An image processing unit that performs outline processing on the image captured by the imaging optical system 213 and the image pickup device 214 to generate image processing data, and generates an image of the electron beam 203 based on the shot shape of the electron beam 203. By comparing the intensity distribution predicted by the electromagnetic wave intensity prediction unit with the intensity distribution of the electromagnetic wave generated from the substrate 202 to be exposed by irradiation, and the image processing data created by the image processing unit, And an irradiation position calculating means for obtaining an irradiation position actual measurement value of the electron beam 203 on the substrate 202 to be exposed. Note that the electromagnetic wave intensity prediction means has a shot shape storage means for storing a shot shape of the electron beam 203.

Hereinafter, a specific description will be given with reference to FIG.

The image signal S output from the image sensor 214
Then, the image processing means 218 performs outline processing by contrast adjustment or the like to generate image processing data I.

Further, based on the shot shape Dp of the electron beam 203 stored in the shot shape storage means 219 and the aperture coefficient of the imaging optical system 213, the fluorescence shape calculation means 220 causes the predicted intensity distribution of the fluorescence 211, in other words, And image prediction data Dc which is a prediction value of the image signal S output from the image sensor 214.

In other words, in the third embodiment, the electromagnetic wave intensity calculation means comprises the shot shape storage means 219 and the fluorescence shape calculation means 220, but the configuration of the electromagnetic wave intensity calculation means is not limited to this.

FIG. 5A schematically shows an example of the shot shape Dp, and FIG. 5B corresponds to the irradiation of the electron beam 203 shaped into the shot shape Dp shown in FIG. 5A. An example of the image prediction data Dc is schematically shown.

Next, the irradiation position calculating means 221 compares the image processing data I generated by the image processing means 218 with the image prediction data Dc calculated by the fluorescent shape calculating means 220, thereby obtaining the substrate to be exposed. An irradiation position actual measurement value De of the electron beam 203 in 202 is obtained.

FIG. 5C shows a state where the image processing data I and the image prediction data Dc are compared. still,
In FIG. 5C, the solid line indicates the image prediction data Dc, and the broken line indicates the area corresponding to the image prediction data Dc in the image processing data I.

That is, the irradiation position calculation means 221 superimposes the image prediction data Dc as a template on the image processing data I to obtain a region which best matches the image prediction data Dc in the image processing data I, that is, in the image processing data I By determining a region corresponding to the image prediction data Dc, the position of the determined region is obtained as the irradiation position actual measurement value De.

Next, the comparison operation means 216 calculates the irradiation position actual value De calculated by the irradiation position calculation means 221,
By comparing the deflection position data Dd calculated by the deflection position calculation means 208, the actual irradiation position value De is calculated.
A deviation amount from one irradiation position design data, that is, a beam drift amount ΔD is obtained. Thereafter, the deflection position calculating means 20
8 calculates the deflection position data Dd of the electron beam 203 corresponding to the next irradiation position design data by correcting the beam drift amount ΔD calculated by the comparison calculation means 216.

Next, based on the deflection position data Dd in which the beam drift amount ΔD has been corrected, the deflection voltage generation means 209
After applying a predetermined deflection voltage Vd to the deflection electrode 210,
The voltage of the blanking electrode 204 is turned off, and the irradiation of the electron beam 203 based on the next irradiation position design data is performed. Thereby, beam drift correction is performed by controlling the deflection of the electron beam 203.

As described above, according to the third embodiment, the image processing means 218, the electromagnetic wave intensity predicting means (the shot shape storing means 219 and the fluorescent shape calculating means 220)
And the irradiation position calculation unit 221 realizes the same function as the beam position calculation unit 215 in the second embodiment, so that the same effect as in the second embodiment can be obtained and the electron beam 203 can be obtained. Even in the case of being formed into a predetermined shot shape, the irradiation position actual measurement value De, that is, the beam drift amount ΔD can be accurately obtained.
Beam drift correction can be performed accurately.

Although the electron beam 203 is used as the charged particle beam in the third embodiment, another charged particle beam may be used instead.

In the third embodiment, the beam drift is corrected by controlling the deflection of the electron beam 203. Alternatively, the beam drift may be corrected by controlling the drive of the XY stage 201.

In the third embodiment, the intensity distribution of the electromagnetic wave generated from the substrate 202 to be exposed, that is, the image prediction data Dc is converted into the electron beam 20 by the electromagnetic wave intensity prediction means.
3 was predicted for each irradiation, but instead of this, the electron beam 2
The image prediction data Dc predicted in advance for all the shot shapes 03 may be stored in the storage unit, and the image prediction data Dc stored in the storage unit may be used as appropriate.

In the third embodiment, the image prediction data Dc is calculated on the basis of the shot shape of the electron beam 203. However, when the shot shape of the electron beam 203 is large, of the shot shapes of the electron beam 203, Only characteristic pattern portions may be extracted, and the image prediction data Dc may be calculated based on the extracted pattern portions.

[0089]

According to the present invention, the beam drift amount obtained in the irradiation of the charged particle beam based on one irradiation position design data is corrected, and the irradiation of the charged particle beam based on the next irradiation position design data is performed. Therefore, beam drift correction can be performed each time a charged particle beam is irradiated without interrupting pattern writing and moving the wafer stage, thereby improving the positional accuracy of pattern exposure while preventing a decrease in throughput. be able to.

[Brief description of the drawings]

FIGS. 1A to 1D are cross-sectional views illustrating respective steps of a pattern forming method according to a first embodiment.

FIG. 2 is a schematic view of a charged particle beam exposure apparatus according to a second embodiment.

FIG. 3 is a schematic view of a charged particle beam exposure apparatus according to a modification of the second embodiment.

FIG. 4 is a schematic view of a charged particle beam exposure apparatus according to a third embodiment.

5A is a diagram illustrating an example of an electron beam shot shape Dp, and FIG. 5B is a diagram illustrating image prediction data Dc corresponding to the irradiation of the electron beam shaped into the shot shape Dp illustrated in FIG. FIG. 7C is a diagram showing an example in which image processing data I and image prediction data Dc are compared.

FIG. 6 is a perspective view of a conventional charged particle beam exposure apparatus.

[Explanation of symbols]

 Reference Signs List 101 substrate 102 resist film 103 fluorescent material film 104 electron beam 105 fluorescence 106 resist pattern 201 XY stage 202 exposed substrate 203 electron beam 204 blanking electrode 205 blanking aperture 206 laser interferometer 207 drawing data storage means 208 deflection position calculation Means 209 Deflection voltage generating means 210 Deflection electrode 211 Fluorescent light 212 Reflecting mirror 212a Opening 213 Imaging optical system 214 Imaging element 215 Beam position calculating means 216 Comparison calculating means 217 Stage driving means 218 Image processing means 219 Shot shape storage means 220 Fluorescent shape Calculation means 221 Irradiation position calculation means L Position data of XY stage 201 D Irradiation position design data of electron beam 203 Dd Deflection position data of electron beam 203 Vd polarization Voltage S image signal De shots shape of the irradiation position measured value ΔD beam drift amount Dp electron beam 203 of the electron beam 203 I imaging data Dc image predictive data

Claims (7)

[Claims] A resist film forming step of applying a resist material on a substrate to form a resist film; and a method of applying a charged particle beam to the resist film in advance to draw a predetermined pattern on the resist film. An exposure step of performing pattern exposure by irradiating the prepared based on irradiation position design data that is design data of the irradiation position of the charged particle beam, and a pattern for forming the resist pattern by developing the pattern-exposed resist film. A pattern forming method comprising: forming a fluorescent material that generates fluorescence by irradiation of the charged particle beam on the resist film, between the resist film forming step and the exposing step. The method further includes a fluorescent material film forming step of forming a fluorescent material film, wherein the exposing step includes the step of irradiating the charged particle beam from the fluorescent material film. Capturing the generated fluorescence as an image; processing the image to determine an irradiation position actual measurement value of the charged particle beam on the resist film; and a deviation amount of the irradiation position actual value from the irradiation position design data. And a step of correcting the beam drift amount. 2. The pattern forming method according to claim 1, wherein the resist material has no sensitivity to the fluorescent light generated from the fluorescent material film. 3. The resist material becomes soluble in an alkaline solution by irradiation of the charged particle beam,
The fluorescent material is water-soluble.
4. The pattern forming method according to 1. 4. A resist film forming step of forming a resist film by applying a resist material on a substrate, and applying a charged particle beam to the resist film in advance to draw a predetermined pattern on the resist film. An exposure step of performing pattern exposure by irradiating the prepared based on irradiation position design data that is design data of the irradiation position of the charged particle beam, and a pattern for developing the resist film subjected to pattern exposure to form a resist pattern. A pattern forming method comprising: forming the resist material, wherein the resist material includes a material that generates fluorescence by irradiation of the charged particle beam; and the exposing step includes: Capturing the generated fluorescence as an image; processing the image to illuminate the charged particle beam on the resist film. A step of obtaining an actual measurement value of the irradiation position; a step of obtaining a deviation amount of the actual measurement value of the irradiation position from the irradiation position design data as a beam drift amount; and a step of correcting the beam drift amount. Forming method. 5. The pattern forming method according to claim 4, wherein said resist material has no sensitivity to fluorescence generated from said resist film. 6. A charged particle beam, which is prepared in advance on a substrate, for drawing a predetermined pattern on the substrate,
A charged particle beam exposure apparatus that performs pattern exposure by irradiating based on irradiation position design data that is design data of an irradiation position of the charged particle beam, wherein an electromagnetic wave generated from the substrate by the irradiation of the charged particle beam is used as an image. An image input unit to be captured, a beam position calculating unit that processes the image and obtains a measured value of the irradiation position of the charged particle beam on the substrate, and a beam that calculates a deviation amount of the measured irradiation position from the irradiation position design data. A charged particle beam exposure apparatus, comprising: comparison operation means for obtaining a drift amount; and beam drift correction means for correcting the beam drift amount. 7. The charged particle beam is shaped into a predetermined shape, the beam position calculating means processes the image to create image processing data, and based on the shape of the charged particle beam, Means for predicting or previously storing the intensity distribution of the electromagnetic wave generated from the substrate by the irradiation of the charged particle beam, and comparing the intensity distribution with the image processing data to obtain the measured irradiation position. The charged particle beam exposure apparatus according to claim 6, further comprising a calculating unit.