JP2005259863A - Electron beam exposure apparatus and electron beam exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron beam exposure apparatus and an electron beam exposure method capable of correcting a deflection distortion of a sub deflector.
An electron beam exposure apparatus includes a deflection distortion information storage unit that stores deflection distortion information that is deviation information of a deflection angle caused by deflection distortion of sub-deflectors 51 and 52 acquired in advance, and a sub-deflector 51. And an incident angle information correction unit 74 that corrects the incident angle information commanded to 52 and 52 based on the deflection distortion information.
[Selection] Figure 7

Description

  The present invention relates to an electron beam exposure apparatus that exposes a fine pattern used in a manufacturing process of a semiconductor integrated circuit and the like, and in particular, a mask having an opening corresponding to the exposure pattern is arranged close to the surface of a sample such as a semiconductor wafer. The present invention relates to an electron beam proximity exposure apparatus that performs exposure with an electron beam that has passed through an aperture by irradiating an electron beam onto a mask.

  In recent years, with the need for higher integration of semiconductor integrated circuits, further miniaturization of circuit patterns has been demanded. At present, the limits of miniaturization are mainly limited to exposure apparatuses, and new exposure apparatuses such as an electron beam direct writing apparatus and an X-ray exposure apparatus have been developed.

  Recently, an electron beam proximity exposure apparatus that can be used for ultrafine processing at a mass production level has been disclosed as a new type of exposure apparatus (for example, Patent Document 1 and Patent Document 2 corresponding to Japanese Patent Application). .

  FIG. 1 is a diagram showing a basic configuration of an electron beam proximity exposure apparatus disclosed in Patent Document 1. As shown in FIG. The electron beam proximity exposure apparatus will be briefly described with reference to this figure. As shown in the figure, an electron gun 12 having an electron beam source 14 for generating an electron beam 15, a shaping aperture 18, and an irradiation lens 16 for making the electron beam 15 a parallel beam, in an electron optical column (column) 10. A scanning unit 20 that includes a pair of main deflectors 21 and 22 and a pair of sub-deflectors 51 and 52, and that scans the electron beam 15 parallel to the optical axis 19, and a mask having an opening corresponding to the pattern to be exposed. 30, and an electrostatic chuck 44 and an XY stage 46. A sample (semiconductor wafer) 40 has a resist layer 42 formed on the surface thereof and is held on an electrostatic chuck 44.

  The mask 30 has a thin film portion 32 in which an opening is formed at the center portion of the thick outer edge portion 34, and the sample 40 is arranged so that the surface is close to the mask 30. In this state, when the electron beam 15 is irradiated perpendicularly to the mask, the electron beam 15 that has passed through the opening of the mask is irradiated onto the resist layer 42 on the surface of the sample 40.

  The main deflectors 21 and 22, which are a pair of deflectors realized by an electrostatic lens, a magnetic lens, or the like, control the deflection of the electron beam 15 so as to scan the entire surface of the thin film portion 32 of the mask 30. As shown in FIG. 2, when the electron beam 15 scans the entire surface of the thin film portion 32, the mask pattern of the mask 30 is transferred to the resist layer 42 on the sample 40 at the same magnification.

  The XY stage 46 moves the sample 40 adsorbed by the electrostatic chuck 44 in two horizontal orthogonal axes, and moves the sample 40 by a predetermined amount every time when the mask pattern equal magnification transfer is completed. A plurality of mask patterns can be transferred to a single sample 40.

The sub deflectors 51 and 52 in the scanning unit 20 are realized by an electrostatic lens, a magnetic lens, or the like, and control (tilt control) the incident angle of the electron beam 15 on the mask pattern so as to correct the mask distortion. As shown in FIG. 3, when the incident angle of the electron beam 15 to the exposure mask 30 is α and the gap between the exposure mask 30 and the wafer 40 is G, the shift amount δ of the transfer position of the mask pattern due to the incident angle α. Is
δ = G ・ tanα
It is represented by In FIG. 3, the mask pattern is transferred to a position shifted from the normal position by a shift amount δ.

  Therefore, when the exposure mask 30 has a mask distortion as shown in FIG. 4A, for example, the tilt of the electron beam is controlled according to the mask distortion at the electron beam scanning position. As shown in FIG. 4B, it is possible to transfer the mask pattern without mask distortion.

US Pat. No. 5,831,272 (Overall) Japanese Patent No. 2951947 (Overall)

  However, the electric field and magnetic field generated by the sub deflectors 51 and 52 are distorted due to mechanical attachment errors of electrodes constituting the deflector, electrode characteristics, and the like. Due to the distortion of the electric field and the magnetic field, a deflection between the deflection distortion of the sub deflectors 51 and 52, that is, the deflection command value input to the sub deflectors 51 and 52 and the actual deflection angle of the electron beam 15 occurs.

FIG. 5 is an explanatory diagram of the deflection distortion generated in the sub deflectors 51 and 52. The incident angle [rad] in the x direction when entering the mask 30 is set to the x coordinate, and the incident angle [rad] in the y direction is set to y. Shown in coordinates. The electron beam 15 deflected by the sub-deflectors 51 and 52 to which the sub-deflection command values P1, P2, P3, P4, P5, P6, P7, P8 or P9 are input is shifted, enlarged or reduced. Due to deflection distortion such as rotation, trapezoidal distortion, x-direction arcuate distortion, or y-direction arcuate distortion, at the same deflection angle as the sub-deflection command values P1, P2, P3, P4, P5, P6, P7, P8 or P9. It is not deflected but deflected to slightly shifted deflection angles P1 ′, P2 ′, P3 ′, P4 ′, P5 ′, P6 ′, P7 ′, P8 ′ or P9 ′.
Therefore, even if the incident angle of the electron beam 15 is deflected within the sub-deflection command value range 91 shown in the figure, the actual electron beam 15 is deflected within a deflection angle range 92 different from the range 91.

  Further, the deflection distortion amount also varies depending on the main deflection amount by the main deflectors 21 and 22. That is, the amount of deflection distortion of the sub deflectors 51 and 52 differs depending on the deflection position on the mask 30 of the electron beam deflected by the main deflectors 21 and 22.

FIG. 6 is an explanatory diagram of the deflection distortion of the sub deflector that varies depending on the main deflection amount. It is assumed that the deflection position in the x direction on the mask 30 irradiated with the electron beam 15 is indicated by the X coordinate, and the deflection position in the y direction is indicated by the Y coordinate.
Deflection distortion of the sub deflectors 51 and 52 of the electron beam 15 deflected to the deflection positions 94A, 94B, 94C, 94D, 94E, 94F, 91G, 94H and 94I in the deflection region 93 of the main deflectors 21 and 22 Are different at each deflection position, and the actual deflection angle range of the electron beam 15 deflected by the command values of the sub-deflection command values 91A, 91B, 91C, 91D, 91E, 91F, 91G, 91H and 91I at each deflection position. Are as shown in ranges 92A, 92B, 92C, 92D, 92E, 92F, 92G, 92H and 92I, respectively.

Due to the above-described deflection distortion of the sub-deflector and fluctuations in the nonlinearity of the deflection distortion depending on the main deflection amount, a deviation between the calculated irradiation position on the sample 40 of the electron beam 15 and the actual irradiation position occurs. This causes unevenness in the exposure amount of the sample and causes deterioration of the resolution of the exposure pattern.
Further, when the overlay correction between the ground pattern already formed on the sample 40 and the pattern to be exposed in the previous process is performed by the tilt correction by the sub deflector, the overlay accuracy is also deteriorated.

  In view of the above problems, an object of the present invention is to provide an electron beam exposure apparatus and an electron beam exposure method capable of correcting the deflection distortion of the sub deflector.

  In order to achieve the above object, the present invention acquires in advance deflection distortion information of a deflector that deflects the incident angle of the electron beam on the mask, and corrects the incident angle information commanded to the deflector based on the deflection distortion information. To do.

  That is, the electron beam exposure apparatus according to the first embodiment of the present invention includes an electron beam source that generates an electron beam, a mask including a mask pattern corresponding to a pattern to be exposed on a sample surface, and an incident angle of the electron beam to the mask. An electron beam exposure apparatus that exposes a mask pattern on the surface of a sample with an electron beam that has passed through a mask, and is information on deflection angle deviation caused by deflection distortion of the deflector acquired in advance. A deflection distortion information storage unit that stores deflection distortion information, and an incident angle information correction unit that corrects incident angle information commanded to the deflector based on the deflection distortion information.

  The electron beam exposure method according to the second embodiment of the present invention is an electron beam exposure method in which a beam is generated from an electron beam source and a mask having a mask pattern corresponding to a pattern to be exposed on a sample surface is incident on the electron beam by a deflector. This is an electron beam exposure method that exposes the mask pattern on the sample surface with an electron beam that has passed through the mask while deflecting it, and obtains deflection distortion information that is information on the deflection angle caused by the deflection distortion of the deflector. Then, the incident angle information commanded to the deflector is corrected based on the deflection distortion information.

  When deflecting the electron beam to each deflection position in a predetermined deflection area on the mask, the deflection distortion information is acquired or stored for each deflection position in the deflection area, and the electron beam is stored. The incident angle information commanded to the deflector may be corrected based on the stored deflection distortion information according to the current deflection position.

  According to the present invention, it is possible to correct the deflection distortion of the sub-deflector and greatly reduce the deviation of the deflection angle of the sub-deflector. Is eliminated, and the exposure amount unevenness of the sample and the deterioration of the resolution of the exposure pattern are reduced.

  Further, when overlay correction between the base pattern and the pattern to be exposed is performed by the sub deflector, overlay accuracy is improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 7 is a basic block diagram of an electron beam proximity exposure apparatus according to an embodiment of the present invention. The basic configuration of the electron beam proximity exposure apparatus 1 has a configuration similar to the configuration shown in FIG. 1 and the configuration disclosed in Document 1 above. Therefore, the same functional parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
The present invention is preferably used in a proximity exposure type electron beam exposure apparatus, but can be widely applied to an electron beam exposure apparatus in which an incident angle to a mask is controlled by a deflector.

  As shown in FIG. 7, the electron beam proximity exposure apparatus 1 includes a column 10 and a chamber 8. In the column 10, an electron gun 12 having an electron beam source 14 for generating an electron beam 15, a shaping aperture 18 and an irradiation lens 16 for making the electron beam 15 a parallel beam, a pair of main deflectors 21 and 22, Deflection means scanning means 20 that includes a pair of sub-deflectors 51 and 52 and deflects the electron beam 15 so as to scan parallel to the optical axis 19, a mask 30 having an opening corresponding to the pattern to be exposed, electrostatic A chuck 44 and an XY stage 46 are included. A sample (semiconductor wafer) 40 has a resist layer 42 formed on the surface thereof and is held on an electrostatic chuck 44.

The mask 30 is disposed so as to be close to the surface of the sample 40 adsorbed by the electrostatic chuck 44 (so that the gap between the mask 30 and the sample 40 is, for example, 50 μm).
The sub deflectors 51 and 52 are the first deflectors of the electron beam exposure apparatus according to the claims of the present invention, and the main deflectors 21 and 22 are the second deflectors of the electron beam exposure apparatus according to the claims of the present invention. This is a deflector.

  Further, the electron beam proximity exposure apparatus 1 includes a deflection position information supply unit 71 that supplies deflection position information indicating a deflection position, which is a position on the mask 30 where the electron beam 15 is to be deflected by the main deflectors 21 and 22; A main deflector control unit 72 that determines main deflection command values of the main deflectors 21 and 22 based on the deflection position information supplied by the deflection position information supply unit 71 and supplies the command values to the main deflectors 21 and 22 is provided.

  Further, the electron beam proximity exposure apparatus 1 supplies incident angle information for controlling the inclination of the incident angle of the electron beam 15 on the mask 30 based on the distortion amount of the mask 30 stored in the memory 62. An incident angle information correcting unit 74 that corrects incident angle information supplied from the incident angle information supplying unit 73 based on deflection distortion information described later stored in the memory 62 and an incident angle information correcting unit 74. A sub-deflector control unit 75 that determines sub-deflection command values of the sub-deflectors 51 and 52 based on the corrected incident angle information corrected by the step S and supplies the sub-deflection command values to the sub-deflectors 51 and 52 is provided.

  The overall control of the electron beam proximity exposure apparatus 1 is performed by a computer 60 realized by a computer or the like. The memory 62, the deflection position information supply unit 71, and the incident angle information supply unit 73 are connected to the data bus 61 of the computer 60 and can exchange data with each other and with the computer 60.

FIG. 8 is a flowchart of the electron beam exposure method according to the present invention.
Before exposure of the sample 40, in step S101, deflection distortion information, which is deviation information of the deflection angle caused by the deflection distortion of the deflector, is generated for each deflection position in the deflection area of the main deflectors 21 and 22, and is stored in the memory. 62 respectively. The creation of deflection distortion information will be described later.

  When the exposure is started and the electron beam proximity exposure apparatus 1 scans the electron beam 15 on the mask 30, the deflection position information supply unit 71 performs scanning on the mask of the electron beam 15 in accordance with a scanning command from the computer 60 in step S 102. The deflection position information indicating the deflection position is generated and supplied to the main deflector control unit 72.

  The main deflector control unit 72 determines the deflection amount of the main deflectors 21 and 22 based on the supplied deflection position information, and supplies the main deflector command value corresponding to the determined deflection amount to the main deflectors 21 and 22. To do. The main deflectors 21 and 22 deflect the electron beam 15 by a deflection amount corresponding to the supplied main deflection command value, and deflect it to the deflection position indicated by the deflection position information generated by the deflection position information supply unit 71.

In step S103, the incident angle information supply unit 73 acquires the distortion amount of the mask 30 at this deflection position from the memory 62 based on the deflection position information generated by the deflection position information supply unit 71, and controls the tilt of the electron beam 15. Find the incident angle to do.
Then, incident angle information indicating the incident angle is supplied to the incident angle information correction unit 74.

In step S104, the incident angle information correction unit 74, based on the deflection position information generated by the deflection position information supply unit 71, correction coefficients that are deflection distortion information stored for the deflection position, A ₁ , A ₂ , A _3. , A ₄ , A ₅ and A ₆ and B ₁ , B ₂ , B ₃ , B ₄ , B ₅ and B ₆ are read from the memory 62.

Here, A _{1 to} A ₆ are correction coefficients related to the deflection angle in the x direction (hereinafter simply referred to as “in the x direction”), A ₁ is the shift amount in the x direction, and A ₂ is the enlargement in the x direction. reduced weight, _{a 3} is rotated, _{a 4} is trapezoidal distortion, _{a 5} is the x-direction of the bow distortion, _{a 6} is a correction coefficient according to the bow distortion in the y direction.

B _{1 to} B ₆ are correction coefficients related to a deflection angle in the y direction (hereinafter simply referred to as “y direction”), B ₁ is a shift amount in the y direction, and B ₂ is an enlargement / reduction in the y direction. B ₃ is rotation, B ₄ is trapezoidal distortion, B ₅ is bow distortion in the y direction, and B ₆ is a correction coefficient related to bow distortion in the x direction.
Here, the x direction and the y direction are defined as, for example, the x direction and the y direction in the mask coordinate system defined on the plane of the mask 30 as shown in FIG.

  In step S105, the incident angle information correction unit 74 corrects and corrects the incident angle information supplied from the incident angle information supply unit 73 by the following formulas (1) and (2) based on the read deflection distortion information. Find incident angle information.

Here, x _c, y _c is x direction indicated incidence angle information supplied from the incident angle information supply unit 73 are each incident angle in the y-direction, here, x _a, y _a are corrected The incident angles in the x and y directions indicated by the incident angle information.
Then, the incident angle information correction unit 74 supplies the corrected incident angle information to the sub deflector control unit 75.

  In step S <b> 106, the sub deflector control unit 75 determines the deflection amount of the sub deflectors 51 and 52 based on the supplied corrected incident angle information, and outputs a sub deflection command value corresponding to the determined deflection amount. And 52 are sequentially supplied.

  In step S107, the sub deflectors 51 and 52 deflect the electron beam 15 by a deflection amount corresponding to the supplied sub deflection command value.

  In step S108, the deflection position information supply unit 71 determines whether or not the electron beam 15 has been scanned in the entire deflection area. If scanning has been performed in the entire deflection area, the exposure ends. If not, the process returns to step S102. Thus, the electron beam 15 is deflected to the next deflection position.

  Here, the generation of deflection distortion information at each deflection position in step S101 is performed as follows. FIG. 9 is an explanatory diagram of a method of generating deflection distortion information. Assume that the incident angle [rad] in the x direction when entering the mask 30 is indicated by the x coordinate, and the incident angle [rad] in the y direction is indicated by the y coordinate. .

  First, the main deflectors 21 and 22 deflect the electron beam 15 to a deflection position where deflection distortion information is to be acquired.

Then, enter the sub-deflection command value corresponding to a plurality of incident angle information _{p c1, p c2, p c3} , p c4, p c5, p c6, p c7, p c8 and _{p c9} the sub deflector 51, 52 . Then, p _m1 , p _m2 , p _m3 , p _m4 , p _m5 , p _m6 , p _m7 , p _m8, and p _m9 , which are actual incident angles of the electron beam deflected by each incident angle information, are measured.

The incident angle information p _ci (i = 1 to 9) indicates the incident angle in the x direction as x _ci (i = 1 to 9) and the incident angle in the y direction as y _ci (i = 1 to 9). The incident angle in the x direction of the incident angle p _mi (i = 1 to 9) is set to x _mi (i = 1 to 9), and the incident angle in the y direction is set to y _mi (i = 1 to 9).
At this time, for example, the correction coefficients A _{1 to} A ₆ and B _{1 to} B ₆ which are deflection distortion information are expressed by the following simultaneous equations (3) and (4) as A _{1 to} A ₆ and B _{1 to} B _6. Can be obtained by solving for.

Note that the actual incident angles p _mi (i = 1 to 9) of the sub deflectors 51 and 52 based on a larger number of incident angle information p _ci (i = 1 to 9) are measured, and based on the obtained measurement results. By calculating the correction coefficients A _{1 to} A ₆ and B _{1 to} B ₆ by a method such as a least square method, it is possible to obtain with higher accuracy.

The actual incident angle p _mi (i = 1 to 9) of the electron beam deflected by the sub deflectors 51 and 52 should be measured by using an incident angle detector using an imaging element such as a CCD shown below. Is possible.
FIG. 10A is a configuration diagram of an incident angle detector. The incident angle detector 80 receives an aperture plate 81 having electron passage holes 81x and 81y having a predetermined shape as shown in FIG. 10B and the electron beam 15 that has passed through the electron passage holes 81x and 81y, and irradiates them. A fluorescent screen 82 that creates a luminescent image A corresponding to the intensity distribution of the electron beam 15 by emitting light from the location, an image sensor 83 such as a CCD sensor or a CMOS sensor that captures the luminescent image A generated on the fluorescent screen 82, and a fluorescent screen An optical system (focusing lens) 84 that forms a light emission image A generated on the image 82 as a projection image B on the image sensor 83 is provided. The aperture plate 81 and the phosphor screen 82 are arranged with a predetermined distance D therebetween.

  Here, the electron passage hole 81x is an electron passage hole for generating a light emission image for measuring the x direction incident angle on the phosphor screen 82, and the electron passage hole 81y is for measuring the y direction incident angle. This is an electron passage hole for generating a light emission image of the above on the phosphor screen 82.

Prior to the measurement of the incident angle of the electron beam 15, the reference position of the emission image A generated on the phosphor screen 82 by the electron beam 15 incident perpendicularly to the mask 30 is measured and stored in advance.
Here, the measurement of the reference position of the light emission image A may be performed as follows, for example.

First, the x-direction profile and the y-direction profile of the emission intensity of the emission images Ax and Ay respectively generated by the electron beams that have passed through the x-position measurement passage hole 81x and the y-position measurement passage hole 81y are obtained.
FIG. 10C shows an image Ax and an image Ay of the light emission image A generated by the electron beams that have passed through the x-position measurement passage hole 81x and the y-position measurement passage hole 81y, and the respective x-direction intensity profiles and y-directions. An intensity profile is shown.
Then, the x position and the y position having the highest emission intensity are measured and stored as the reference position p0 of the image A having x and y coordinates.

Then, enter the secondary correction command value based on the incident angle information p _c in the sub-deflector 51 and 52. A light emission image formed on the fluorescent screen 82 by the electron beam 15 deflected by the sub deflectors 51 and 52 and having an incident angle inclined through the aperture plate 81 is a light emission image A ′ shown in FIG. As described above, the position is shifted from the light emission image A generated by the electron beam 15 incident perpendicularly to the mask 30. In the example of FIG. 10D, the distance is shifted by dx in the x direction and dy in the y direction.

  Then, the position p0 ′ of the luminescent image A ′ is measured by the same method as the method for measuring the reference position of the luminescent image A described with reference to FIG. Then, the x-direction incident angle θx and the y-direction incident angle θy are obtained by the following equations, respectively.

θx = Tan ⁻¹ (dx / D)
θy = Tan ⁻¹ (dy / D)

Here, dx and dy are the amounts of displacement (dx, dy) in the x and y directions between the position p0 ′ of the light emission image A ′ and the reference position p0 of the light emission image A, respectively, and D is the aperture plate. 81 and the distance between the phosphor screen 82.
Of the electron beam 15 deflected by the sub deflector 51, 52 which is input to the sub deflection command value based on the incident angle information p _c the above, it is possible to an actual incident angle p _m, measured.

The actual angle of incidence p _m of deflected electron beam by the sub deflector 51, 52 may be measured using the incident angle detector using an electronic detector such as a Faraday cup below. FIG. 11A is a configuration diagram of an incident angle detector using an electron detector.

  The incident angle detector 80 includes an aperture plate 85 having an electron passage hole 86 having a very small diameter with respect to the diameter of the electron beam 15 on the upper surface. An aperture plate 87 having an electron passage hole 88 having the same diameter as the electron passage hole 86 is further provided below the aperture plate 85.

The aperture plates 85 and 87 are arranged so as to be overlapped in the optical axis direction of the electron beam 15 at a predetermined interval, and the electron passage holes 86 and 88 are arranged perpendicular to the surface of the mask 30.
An electron detector 89 such as a Faraday cup is provided below the aperture plate 87. The electron detector 89 detects the electrons that have passed through the electron passage holes 86 and 88, converts the amount of electrons into an electrical signal, and outputs the electrical signal.
In the incident angle detector 80 configured as described above, the amount of electrons detected by the electron detector 89 through the electron passage holes 86 and 88 is the largest because the electron beam is perpendicular to the electron passage holes 86 and 88. The output signal of the incident angle detector 80 becomes weaker as the incident angle of the electron beam is inclined.

  The principle of incident angle detection by the incident angle detector 80 having such a structure will be described with reference to FIG. First, the electron beam 15 is incident on the incident angle detector 80 while gradually changing the incident angle around the incident angle to be measured. Then, the output signal of the electron detector 89 of the incident angle detector 80 at each time point is acquired and stored.

  FIG. 11B is an intensity distribution diagram showing the relationship between the variation amount of the incident angle and the intensity of the output signal of the electron detector 89. In the figure, the x-coordinate and the y-coordinate indicate the incident angle fluctuation amount (dx, dy) in the x direction and the y direction, respectively.

Using the intensity distribution diagram generated in this way, the incident angle fluctuation amount dθ _{max at} which the signal intensity of the electron detector 89 is the strongest is obtained.
As described above, the signal intensity of the electron detector 89 is the strongest when the electron beam enters the electron passage holes 86 and 88 most perpendicularly, so that the incident angle fluctuation amount dθ _max depends on the incident angle to be measured. Changes.

Therefore, prior to the measurement, each incident angle fluctuation amount dθ _max corresponding to each known incident angle is measured and stored in advance as reference information, and the stored reference information is compared with the measured incident angle fluctuation amount dθ _max. By doing so, the incident angle of the measured electron beam can be measured.

The electron beam proximity exposure apparatus 1, when the measurement of the actual incident angle p _m in FIG. 11 using the incident angle detector 80 (A), the electron beam 15 deflected by a certain angle of incidence information p _c is , around the incident angle indicated by the incident angle information p _c, sequentially inputs the sub-deflection command value generated by varying by small angular steps dφ over the fluctuation angular width φ in the sub-deflector 51 and 52. Then, the output signal of the electron detector 89 of the incident angle detector 80 at that time is acquired and stored.

Next, an intensity distribution diagram showing the relationship between the incident angle variation (dx, dy) and the intensity of the output signal of the electron detector 89 as shown in FIG. 11B is generated.
Here, the incidence angle variation amount (dx, dy) is the incident angle indicated by the angle of incidence information p _c, the incident angle corresponding to the sub-deflector is input to the input auxiliary deflection command value, and the difference amount.
And it obtains the incidence angle variation amount d [theta] _max of highest signal intensity of the electron detector 89 uses this intensity distribution diagram is increased, measuring the angle of incidence p _m by collating the reference information and the incident angle variation amount d [theta] _max To do.

On the other hand, the above-mentioned reference information collated with the measured incident angle fluctuation amount dθ _max may be obtained by the following method, for example.
FIG. 12 is an explanatory diagram of a reference information acquisition method. As shown in FIG. 12, the main deflector 21 deflects the electron beam 15 at a known incident angle θr and makes it incident on the incident angle detector 80.
At this time, the incident angle θr is set to Hr from the main deflector 21 to the electron passage hole 86 of the incident angle detector 80, and the optical axis center 19 of the electron beam 15 when the main deflector 21 is not deflected. When the distance on the surface of the mask 30 from the electron passing hole 86 of the incident angle detector 80 to Dr is taken as Dr,

θ = Tan ⁻¹ (Dr / Hr)

Can be determined.
The electron beam 15 deflected by the main deflector 21 to each known incident angle θr and further deflected by the sub-deflectors 51 and 52 by a minute angle step dφ over the varying angle width φ is incident angle. The light enters the detector 80.
Then, the respective output signals of the electron detector 89 at that time are sequentially obtained, and the incident angle fluctuation amount (in this case, the deflection angle by the sub deflectors 51 and 52) and the electron detector as shown in FIG. Each intensity distribution diagram showing the relationship with the intensity of 89 output signals is generated.
Using this intensity distribution chart, each incident angle fluctuation amount dθ _max corresponding to each incident angle θr is acquired and used as the above-described reference information.

Further, the electron beam proximity exposure apparatus 1 is based on the incident angle detector 80 shown in FIGS. 10 (A) and 11 (A) and the incident angle of the electron beam 15 detected by the incident angle detector 80. A deflection distortion information generation unit 76 that generates information may be provided.
The deflection distortion information generation unit 76 detects the actual incident angle p _mi (i is a natural number) of the electron beam 15 deflected by the sub deflectors 51 and 52 by each incident angle information p _ci (i is a natural number). The above correction coefficient, which is deflection distortion information, is calculated by the above equations (3) and (4).

It is a basic block diagram of an electron beam proximity exposure apparatus. It is explanatory drawing of the scanning method of an electron beam. It is explanatory drawing of inclination correction of the electron beam by a sub deflector. It is explanatory drawing of mask distortion correction. It is explanatory drawing of the deflection distortion which arises in a sub deflector. It is explanatory drawing of the deflection distortion of the sub deflector which changes with main deflection amounts. 1 is a basic configuration diagram of an electron beam proximity exposure apparatus according to an embodiment of the present invention. 3 is a flowchart of an electron beam exposure method according to the present invention. It is explanatory drawing of the production | generation method of deflection distortion information. (A) is a block diagram (No. 1) of an incident angle detector, (B) is a top view of an aperture plate 82 provided on the upper part, and (C) is a diagram showing a light emission image A generated on a fluorescent screen. (D) is a diagram for explaining the comparison of the positions of the emission images A and A ′. (A) is a block diagram (No. 2) of an incident angle detector, and (B) is an explanatory view of the measurement principle. It is explanatory drawing of the measurement principle of the incident angle detector of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electron beam proximity exposure apparatus 15 ... Electron beams 21, 22 ... Main deflectors 51, 52 ... Sub deflector 62 ... Storage part 71 ... Deflection position information supply part 72 ... Main deflector control part 73 ... Incident angle information supply part 74 ... Incident angle information correction unit 75 ... Sub deflector control unit 76 ... Deflection distortion information generation unit 80 ... Incident angle detector

Claims (4)

An electron beam source for generating an electron beam, a mask having a mask pattern corresponding to a pattern to be exposed on a sample surface, and a deflector for deflecting an incident angle of the electron beam to the mask, and passes through the mask An electron beam exposure apparatus that exposes the mask pattern on the sample surface with the electron beam,
A deflection distortion information storage unit that stores deflection distortion information that is deviation information of a deflection angle caused by deflection distortion of the deflector acquired in advance;
An incident angle information correction unit that corrects incident angle information commanded to the deflector based on the deflection distortion information;
An electron beam exposure apparatus comprising: A first deflector constituting the deflector;
A second deflector for deflecting the electron beam at each deflection position within a predetermined deflection area on the mask,
The deflection distortion information storage unit stores each deflection distortion information according to each deflection position,
The electron beam exposure apparatus according to claim 1, wherein the incident angle information correction unit corrects incident angle information commanded to the deflector according to a current deflection position of the electron beam. The electron beam generated from an electron beam source and incident on the mask having a mask pattern corresponding to the pattern to be exposed on the sample surface while deflecting the incident angle by a deflector, and passed through the mask. An electron beam exposure method for exposing the mask pattern to the sample surface,
Obtain deflection distortion information that is deviation information of the deflection angle caused by the deflection distortion of the deflector,
An electron beam exposure method, wherein the incident angle information commanded to the deflector is corrected based on the deflection distortion information. Storing the deflection distortion information for each deflection position within a predetermined deflection area on the mask;
Deflecting the electron beam to each deflection position;
4. The electron beam exposure method according to claim 3, wherein incident angle information commanded to the deflector is corrected based on the stored deflection distortion information in accordance with a current deflection position of the electron beam.

Images