JP6180945B2 - Electron beam drawing apparatus and electron beam drawing method - Google Patents

Description

  The present invention relates to an electron beam drawing apparatus and an electron beam drawing method.

  In a lithography process of a semiconductor element constituting a recording medium such as a flash memory or a CPU (Central Processing Unit), an original pattern formed on the mask is transferred to a wafer serving as a substrate of the semiconductor element. In recent years, an original pattern formed on this mask is generally drawn using an electron beam drawing apparatus.

  Usually, a high voltage of about several tens of kV is applied between the cathode and the anode of an electron gun used in an electron beam drawing apparatus. For this reason, electrons emitted from the cathode have a relatively large energy. When this electron collides with the insulator holding the cathode or the Wehnelt electrode, the insulator is charged. When the charge amount of the insulator increases, so-called creeping discharge in which electrons flow like an avalanche may occur.

  If an abnormal discharge such as creeping discharge occurs during pattern drawing, a drawing error occurs in the pattern drawn on the object. Thus, various techniques for suppressing the occurrence of abnormal discharge as described above have been proposed (see, for example, Patent Document 1).

JP 2008-78103 A

  The apparatus disclosed in Patent Document 1 intends to suppress the frequency of occurrence of abnormal discharge by removing discharge factors in advance. By using this device, it is possible to improve the withstand voltage characteristics of the electron gun.

  However, even when the apparatus disclosed in Patent Document 1 is used, abnormal discharge may occur, and as a result, a drawing error may occur in the pattern being drawn.

  The present invention has been made under the above-described circumstances, and an object thereof is to predict the occurrence of abnormal discharge and avoid the occurrence of a drawing error.

In order to solve the above object, an electron beam drawing apparatus according to a first aspect of the present invention provides:
An electron beam drawing apparatus for drawing a pattern on an object using an electron beam,
An insulator in which the cathode of the electron gun is disposed on the lower surface side;
A sensor electrode embedded in the vicinity of the lower surface of the insulator between the cathode and the outer edge of the insulator;
A potential measuring means for measuring the potential of the sensor electrode;
Control means for stopping drawing of the pattern on the object when it is determined that the potential of the sensor electrode is equal to or lower than a threshold based on the measurement result of the potential measuring means;
Is provided.

An electron beam drawing method according to a second aspect of the present invention includes:
An electron beam drawing method for drawing a pattern on an object using an electron beam,
A step of measuring a potential of a sensor electrode embedded in the vicinity of the lower surface of the insulator between the outer edge of the insulator provided with the cathode of the electron gun on the lower surface side and the cathode;
Blanking the electron beam when the potential of the sensor electrode is below a threshold;
including.

  According to the present invention, the occurrence of abnormal discharge is predicted based on the potential of the sensor electrode disposed between the cathode and the outer edge of the insulator. When the occurrence of abnormal discharge is predicted, pattern drawing is stopped. Therefore, pattern drawing errors can be avoided.

It is a figure which shows schematic structure of the electron beam drawing apparatus which concerns on this embodiment. It is the schematic which shows the structure of an electron gun. It is a top view of a sensor electrode. It is a block diagram of a control apparatus. It is a figure which shows the electric potential distribution of the area | region formed in an insulator lower surface. It is a figure for demonstrating transition of the electric potential distribution of the area | region formed in an insulator lower surface. It is a flowchart of a drawing error avoidance process. It is a figure which shows the modification of a sensor electrode. It is a figure which shows the modification of a sensor electrode.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description, an XYZ coordinate system including an X axis, a Y axis, and a Z axis that are orthogonal to each other is used.

FIG. 1 is a diagram showing a schematic configuration of an electron beam drawing apparatus 10 according to the present embodiment. The electron beam drawing apparatus 10 is an apparatus that draws a pattern on a sample (hereinafter referred to as a substrate) 120 such as a mask or a reticle coated with a resist material in an environment where the degree of vacuum is about 10 ⁻⁷ Pa, for example.

  As shown in FIG. 1, an electron beam drawing apparatus 10 includes an irradiation device 20 that irradiates a substrate 120 with an electron beam, a stage device 51 on which the substrate 120 is placed, a vacuum chamber 50 that houses the stage device 51, and an irradiation device. 20 and a control system 100 for controlling the stage device 51 are provided.

  The irradiation device 20 includes a lens barrel 21 whose longitudinal direction is the Z-axis direction, an electron gun 30, a blanking electrode 41, an electric field lens 42, an aperture 43, scanning, and the like, which are sequentially arranged from the upper part to the lower part of the lens barrel 21. An electrode 44 and an objective lens 45 are provided.

  The lens barrel 21 is a cylindrical casing that is open at the bottom. The lens barrel 21 is made of stainless steel and is grounded. The lens barrel 21 is installed above the vacuum chamber 50, and a portion located inside the vacuum chamber 50 has a tapered shape whose diameter decreases downward (−Z direction).

  The electron gun 30 is disposed in the upper part of the lens barrel 21. The electron gun 30 is, for example, a hot cathode type electron gun.

  FIG. 2 is a schematic diagram showing the configuration of the electron gun 30. As shown in FIG. 2, the electron gun 30 includes an insulator 31, a heating electrode 33 projecting downward from the center of the insulator 31, a cathode 34, a Wehnelt electrode 35 provided so as to surround the cathode 34, and a cathode 34. An anode 36 to be disposed and a sensor electrode 32 embedded in the insulator 31 are provided.

  The insulator 31 is a circular plate member having a diameter of about 60 cm. The diameter of the insulator 31 is substantially equal to the inner diameter of the lens barrel 21, and is fixed above the interior of the lens barrel 21. The insulator 31 is made of alumina and has a sensor electrode 32 embedded therein.

  The heating electrode 33 includes a pair of electrodes and is provided at the center of the lower surface of the insulator 31. The heating electrode 33 generates heat when a current flows. For this reason, the cathode 34 supported by the heating electrode 33 is maintained at a certain temperature or higher.

The cathode 34 is supported by the heating electrode 33 at the center of the lower surface of the insulator 31. The cathode 34 is made of, for example, lanthanum hexaboride (LaB ₆ ), and is shaped so that the lower end is about 100 nm.

  The Wehnelt electrode 35 has a diameter of about 20 cm and is made of, for example, iron or stainless steel. The Wehnelt electrode 35 is disposed so as to surround the cathode 34, and an opening 35a is formed below. The Wehnelt electrode 35 focuses the electron beam emitted downward from the cathode 34.

  The anode 36 is a circular member made of copper or the like, and an opening 36a is formed at the center. The anode 36 is supported horizontally with an opening 36 a formed in the center positioned vertically below the cathode 34.

  FIG. 3 is a plan view of the sensor electrode 32. As shown in FIG. 3, the sensor electrode 32 is an annular member made of a metal having a low electrical resistance, such as copper or aluminum. The sensor electrode 32 has a thickness of about 1 mm, a width of about 1 cm, and an inner diameter A of about 50 cm. The sensor electrode 32 is disposed inside the insulator 31. For this reason, it is in the state insulated from the conductor part which comprises the electron beam drawing apparatus 10. FIG.

  As shown in FIG. 2, the sensor electrode 32 is embedded in the vicinity of the lower surface of the insulator 31 on which the cathode 34 is provided, that is, at a distance b from the lower surface of the insulator 31. In the electron gun 30 according to the present embodiment, the distance b is about 1 mm. As shown in FIG. 3, the center of the sensor electrode 32 coincides with the center of the Wehnelt electrode 35 in the XY plane. For this reason, the distance a from the outer edge of the Wehnelt electrode 35 to the inner edge of the sensor electrode 32 is about 15 cm, and the distance L from the outer edge of the Wehnelt electrode 35 to the inner wall surface of the lens barrel 21 is about 20 cm. ing.

  Here, for convenience of explanation, an annular region R colored in FIG. 3 is defined. The annular region R is an annular region defined by the outer edge of the Wehnelt electrode 35 and the outer edge of the insulator 31. An annular sensor electrode region is included in the annular region R.

  Returning to FIG. 1, the blanking electrode 41 is disposed below the electron gun 30. The blanking electrode 41 has a pair of electrodes arranged so as to face each other in the X-axis direction. Then, according to the voltage applied by the scanning device 104, the electron beam emitted from the electron gun 30 is deflected in the + X direction or the -X direction.

  For example, a binary voltage signal of high level and low level is input to the blanking electrode 41. In the blanking electrode 41, when the input voltage signal is at a high level, an electric field is generated between the electrodes, and the electron beam is deflected and blanked. Therefore, a desired pattern can be drawn on the substrate 120 by inputting a voltage signal modulated based on the drawing pattern to the blanking electrode 41. Further, by inputting a high level voltage signal to the blanking electrode 41, the electron beam can be blanked.

  The electric field lens 42 is an annular lens disposed below the blanking electrode 41. The blanking electrode 41 focuses the electron beam that passes through the blanking electrode 41.

  The aperture 43 is a plate-like member having an opening through which an electron beam passes in the center. The aperture 43 is arranged in the vicinity of the point where the electron beam that has passed through the electric field lens 42 converges. As the electron beam passes through the opening of the aperture 43, the outer diameter and shape of the spot are shaped. Further, when the electron beam is deflected by the blanking electrode, the electron beam is shielded by the aperture 43. Thereby, the electron beam is blanked with respect to the substrate 120.

  The scanning electrode 44 is disposed below the aperture 43. The scanning electrode 44 has a pair of electrodes arranged so as to face each other in the X-axis direction and a pair of electrodes arranged so as to face each other in the Y-axis direction. Then, the electron beam that has passed through the aperture 43 is deflected in the X-axis direction or the Y-axis direction in accordance with the voltage applied by the scanning device 104.

  The objective lens 45 is disposed below the scanning electrode 44 and focuses the electron beam that has passed through the scanning electrode 44 onto the surface of the substrate 120 placed on the stage device 51.

  The vacuum chamber 50 is a rectangular parallelepiped hollow member, and a circular opening is formed on the upper surface. The lens barrel 21 of the irradiation device 20 described above is inserted into an opening formed on the upper surface of the vacuum chamber 50.

  The stage device 51 is disposed inside the vacuum chamber 50. The stage device 51 is a stage that can move in the XY plane while the substrate 120 on which a pattern is drawn is held almost horizontally.

  The control system 100 is a system for controlling the irradiation device 20 and the stage device 51. The control system 100 includes a control device 101, a surface potential meter 102, a high voltage power supply device 103, a scanning device 104, and a stage driving device 105.

  FIG. 4 is a block diagram of the control device 101. As shown in FIG. 4, the control device 101 includes a CPU (Central Processing Unit) 101a, a main storage unit 101b, an auxiliary storage unit 101c, an input unit 101d, a display unit 101e, an interface unit 101f, and a system that connects the above-described units. A computer having a bus 101g.

  The CPU 101a reads and executes the program stored in the auxiliary storage unit 101c. Specific operations of the CPU 101a will be described later.

  The main storage unit 101b has a volatile memory such as a RAM (Random Access Memory). The main storage unit 101b is used as a work area for the CPU 101a.

  The auxiliary storage unit 101c includes a nonvolatile memory such as a ROM (Read Only Memory), a magnetic disk, and a semiconductor memory. The auxiliary storage unit 101c stores programs executed by the CPU 101a, various parameters, and the like. Further, information including processing results by the CPU 101a is sequentially stored.

  The input unit 101d has a keyboard and a pointing device such as a mouse. The user instruction is input via the input unit 101d and is notified to the CPU 101a via the system bus 101g.

  The display unit 101e has a display unit such as an LCD (Liquid Crystal Display). The display unit 101e displays, for example, information related to the status of the electron beam drawing apparatus 10 and a drawing pattern.

  The interface unit 101f includes a LAN interface, a serial interface, a parallel interface, an analog interface, and the like. The surface potential meter 102, the high voltage power supply device 103, the scanning device 104, and the stage driving device 105 are connected to the control device 101 via the interface unit 101f.

  The control device 101 configured as described above comprehensively controls the surface electrometer 102, the high voltage power supply device 103, the scanning device 104, and the stage driving device 105.

  The surface potential meter 102 measures the potential of the sensor electrode 32 via the wiring 39 with reference to the potential of the grounded lens barrel 21. Then, the measurement result is output to the control device 101.

  The high voltage power supply device 103 applies a high voltage between the cathode 34 and Wehnelt electrode 35 of the electron gun 30 and the anode 36. In this embodiment, the potential of the anode 36 is 0 V, the potential of the cathode 34 is −51 kV, and the potential of the Wehnelt electrode 35 is −50 kV.

  The scanning device 104 controls the blanking electrode 41, the electric field lens 42, the scanning electrode 44, and the objective lens 45 based on instructions from the control device 101.

  The stage driving device 105 drives the stage device 51 based on an instruction from the control device 101 to move or position the substrate 120.

  In the electron beam drawing apparatus 10 configured as described above, when a drawing start command on the substrate 120 is input, the CPU 101a configuring the control device 101 reads a program stored in the auxiliary storage unit 101c. Then, the CPU 101a starts drawing a pattern on the substrate 120 based on the read program.

  Specifically, the CPU 101 a drives the stage device 51 via the stage driving device 105 and positions the substrate 120 below the irradiation device 20.

  Next, the CPU 101 a drives the high voltage power supply device 103 to apply a voltage to the electron gun 30. As a result, an electron beam is emitted downward from the electron gun 30.

  When an electron beam is emitted from the electron gun 30 of the irradiation device 20, the CPU 101 a controls the electric field lens 42 via the scanning device 104 to focus the electron beam in the vicinity of the opening of the aperture 43 (cross pober point). . At this time, the electron beam passes through the opening of the aperture 43 so that the outer diameter and shape of the spot are shaped. The electron beams that have passed through the aperture 43 once intersect and enter the objective lens 45. The CPU 101 a controls the objective lens 45 via the scanning device 104 to form an image of the electron beam incident on the objective lens 45 on the surface of the substrate 120 held by the stage device 51.

  In parallel with the above operation, the CPU 101 a inputs a binary voltage signal modulated based on the drawing pattern to the blanking electrode 41 via the scanning device 104. Thereby, the electron beam is deflected at a predetermined timing, and blanking is executed intermittently. Further, the CPU 101a controls the voltage applied to the scanning electrode 44 via the scanning device 104, deflects the electron beam in the X-axis direction or the Y-axis direction, and adjusts the incident position of the electron beam with respect to the substrate 120. . Thereby, the upper surface of the substrate 120 held by the stage device 51 is scanned with the electron beam, and a pattern is drawn on the substrate 120.

  When a voltage is applied to the cathode 34 and the Wehnelt electrode 35 constituting the electron gun 30 by the high-voltage power supply device 103, the potential distribution in the annular region R shown in FIG. .

  FIG. 5 is a diagram showing a potential distribution in the annular region R. As shown in FIG. In the graph shown in FIG. 5, the horizontal axis indicates the position x from the outer edge of the Wehnelt electrode 35 to the outer edge of the insulator 31. The vertical axis indicates the potential Vs at the position x.

  The potential at the outer edge of the Wehnelt electrode 35 is equal to the potential of the Wehnelt electrode 35. Therefore, the potential −V1 at the position 0 (x = 0) is −50 kV. Further, the potential at the outer edge of the insulator 31 is equal to the potential of the grounded lens barrel 21. Therefore, the potential at the position L (x = L) is 0 kV. Further, as shown in FIG. 5, the electric potential of the annular region R increases from the inside toward the outside. In the vicinity of the Wehnelt electrode 35 (x = 0), the potential changes abruptly, and the potential changes gradually as the outer edge (x = L) of the insulator 31 is approached.

  As described above, the potential of the annular region R is continuously distributed from the Wehnelt electrode 35 to the insulator 31 and normally does not vary greatly. However, for example, when the surface of the insulator 31 is charged, the potential distribution in the annular region R on the lower surface of the insulator 31 is, as shown in FIG. 6, sequentially from the state indicated by the curve L1, the state indicated by the curve L2, and the curve There are cases where the state shown by L3, the state shown by the curve L4, and the state shown by the curve L5 are shifted.

  In this case, initially, the potential difference for the distance L (= 20 cm) is V1 (= 50 kV), but the potential difference for the distance La (= 5 cm) is V1 (= 50 kV).

  In the case of alumina as a material for the insulator 31, the bulk withstand voltage is about 1000 kV / m. In general, the creeping withstand voltage of an insulator is about one-tenth of the withstand voltage of the bulk, so that the creeping withstand voltage of the insulator 31 made of aluminum can be considered to be 100 kV / m. Therefore, in the case where the material of the insulator 31 is alumina, and the potential of the Wehnelt electrode 35 is −50 kV, the insulation on the insulator 31 surface is broken when the potential Vs at the position “a” becomes about −50 kV. And abnormal discharge may occur. Note that the potential distribution immediately before the occurrence of the abnormal discharge is considered to be in a state approximately indicated by a curve L5 in FIG.

  As shown in FIG. 3, the sensor electrode 32 is located at a distance a from the Wehnelt electrode 35. For this reason, the potential of the sensor electrode 32 is substantially equal to the potential of the lower surface of the insulator 31 at the position a shown in FIG. Therefore, the CPU 101a detects and monitors the potential of the insulator 31 at the position a based on the output signal from the surface electrometer 102. Then, based on the monitoring result, a drawing error avoidance process for avoiding a drawing error due to abnormal discharge is performed.

  In the drawing error avoidance process, the occurrence of abnormal discharge is predicted by monitoring the potential of the sensor electrode 32, and when drawing of the abnormal discharge is predicted, pattern drawing is temporarily stopped. Hereinafter, the drawing error avoidance process will be described with reference to FIG.

  The flowchart shown in FIG. 7 is a flowchart showing a series of processing performed by the CPU 101a. This series of processing is executed when a pattern is drawn on the substrate 120.

  In the drawing error avoidance process, the CPU 101a detects the potential Vs of the sensor electrode 32 based on the output signal from the surface electrometer 102 in the first step S101.

  In the next step S102, the CPU 101a determines whether or not the potential Vs of the sensor electrode 32 is equal to or less than a threshold value Th1. As shown in FIG. 6, the threshold Th1 is smaller than f (a) when the potential f (0) at the position 0 is −V1 (= −50 kV), and the potential Th1 is the potential at the position L / 2. When g (L / 2) is −V1, it is set to be larger than g (a). In the present embodiment, the value of the threshold value Th1 is about −7.5 kV.

  If the CPU 101a determines in step S102 that the potential Vs of the sensor electrode 32 is greater than the threshold Th1 (step S102: No), the CPU 101a returns to step S101. And the process of step S101, S102 is repeatedly performed.

  On the other hand, if the CPU 101a determines in step S102 that the potential Vs of the sensor electrode 32 is equal to or less than the threshold Th1 (step S102: Yes), the CPU 101a proceeds to step S103. When the potential Vs of the sensor electrode 32 is equal to or lower than the threshold value Th1, the potential distribution between the insulator 31 and the lens barrel 21 is, for example, shown by a curve L4 as can be seen with reference to FIG. In this case, CPU101a estimates that creeping discharge will generate | occur | produce on the surface of the insulator 31, and performs the process after step S103.

  In step S103, the CPU 101a stops drawing the pattern on the substrate 120. Specifically, the CPU 101a instructs the scanning device 104 to blank the electron beam. When receiving the blanking instruction, the scanning device 104 drives the blanking electrode 41 to perform blanking of the electron beam. Thereby, the electron beam is deflected as shown by the broken line in FIG.

  In step S104, the CPU 101a changes the voltage applied to the Wehnelt electrode 35 to a voltage lower than −50 kV. Specifically, the CPU 101a instructs the high voltage power supply device 103 to lower the applied voltage. As a result, the voltage applied to the cathode 34 and Wehnelt electrode 35 is stepped down by about −10%, the voltage applied to the cathode 34 becomes about −56 kV, and the overvoltage to the Wehnelt electrode 35 becomes about −55 kV. As a result, discharge is induced between the Wehnelt electrode 35 and the lens barrel 21.

  In the next step S105, the CPU 101a detects the potential Vs of the sensor electrode 32 based on the output signal from the surface electrometer 102.

  In the next step S105, the CPU 101a determines whether or not the potential Vs of the sensor electrode 32 is equal to or higher than a threshold value Th2. The voltage applied to the cathode 34 and the Wehnelt electrode 35 is stepped down by the process of step S104. For this reason, the threshold value Th2 may be the same value as the threshold value Th1, but may be a slightly smaller value.

  When the CPU 101a determines in step S105 that the potential Vs of the sensor electrode 32 is smaller than the threshold Th2 (step S106: No), the CPU 101a returns to step S105. Then, the processes of steps S105 and S106 are repeatedly executed.

  On the other hand, when the CPU 101a determines in step S106 that the potential Vs of the sensor electrode 32 is equal to or higher than the threshold Th2 (step S106: Yes), the CPU 101a proceeds to step S107. When a discharge occurs between the Wehnelt electrode 35 and the lens barrel 21, the potential distribution in the annular region R located between the Wehnelt electrode 35 and the lens barrel 21 returns to the state shown by the curve L1 in FIG. For this reason, when a discharge occurs between the Wehnelt electrode 35 and the lens barrel 21 by the process of step S104, the CPU 101a determines that the potential Vs of the sensor electrode 32 is equal to or higher than the threshold Th2.

  In step S107, the CPU 101a restores the voltage applied to the Wehnelt electrode 35. Specifically, the CPU 101a instructs the high voltage power supply device 103 to restore the applied voltage. As a result, the voltage applied to the cathode 34 becomes −51 kV, and the printing voltage to the Wehnelt electrode 35 becomes −50 kV.

  In the next step S108, the CPU 101a resumes drawing on the substrate 120. Specifically, the CPU 101a instructs the scanning device 104 to stop blanking of the electron beam. Upon receiving the blanking stop instruction, the scanning device 104 stops driving the blanking electrode 41 and cancels the blanking of the electron beam. Thereby, pattern drawing by the electron beam is resumed.

  When the processing in step S108 is completed, the CPU 101a returns to step S101. Then, the processes from step S101 to S108 are repeatedly executed.

  As described above, in the present embodiment, the potential of the sensor electrode 32 embedded in the insulator 31 is detected (step S101). Then, the potential of the sensor electrode 32 and the threshold Th1 are compared (Step S102), and when the potential of the sensor electrode 32 becomes equal to or lower than the threshold Th1 (Step S102: Yes), it is determined that creeping discharge occurs on the lower surface of the insulator 31. Then, electron beam blanking is executed. As a result, pattern drawing on the substrate 120 is stopped (step S103).

  Also, when the pattern drawing is stopped, the potential of the sensor electrode 32 is detected (step S105), and the potential of the sensor electrode 32 is compared with the threshold Th2 (step S106). When the potential of the sensor electrode 32 becomes equal to or higher than the threshold Th2 (step S106: Yes), it is determined that creeping discharge has occurred on the lower surface of the insulator 31, the insulation of the insulator 31 has been restored, and pattern drawing is resumed. (Step S108).

  As described above, in this embodiment, when it is predicted that creeping discharge will occur on the lower surface of the insulator 31, the pattern drawing is temporarily stopped. For this reason, it is possible to draw an error-free pattern on the substrate 120 by eliminating the adverse effect of abnormal discharge on the surface of the insulator 31.

  As mentioned above, although embodiment of this invention was described, this invention is not limited by the said embodiment. For example, in the above embodiment, the potential of the sensor electrode 32 is detected using the surface potentiometer 102. Not only this but the electric potential of the sensor electrode 32 may be detected using an electrometer.

  In the present embodiment, as shown in FIG. 3, the case where the sensor electrode 32 is annular has been described. For example, as shown in FIG. 8, a plurality of sensor electrodes 32 may be arranged along a circle having a diameter A. By measuring the potentials of the plurality of sensor electrodes 32 individually, it is possible to specify a position where the frequency of creeping discharge is high.

  In the present embodiment, as shown in FIG. 3, the case where the sensor electrode 32 is arranged at a position where the distance from the Wehnelt electrode 35 is a has been described. Not limited to this, as shown in FIG. 9, the potentials of the plurality of sensor electrodes 32 having different distances from the Wehnelt electrode 35 may be measured. Each of the sensor electrodes 32 shown in FIG. 9 may be composed of a plurality of electrodes as shown in FIG.

  In the present embodiment, when the occurrence of creeping discharge is predicted, the applied voltage of the Wehnelt electrode 35 is stepped down to induce the creeping discharge. However, the present invention is not limited to this, and the occurrence of creeping discharge may be waited for without changing the applied voltage of the Wehnelt electrode 35.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Electron beam drawing apparatus 20 Irradiation apparatus 21 Lens barrel 30 Electron gun 31 Insulator 32 Sensor electrode 33 Heating electrode 34 Cathode 35 Wehnelt electrode 35a Opening 36 Anode 36a Opening 39 Wiring 41 Blanking electrode 42 Electric field lens 43 Aperture 44 Scanning electrode 45 Objective lens 50 Vacuum chamber 51 Stage device 100 Control system 101 Control device 101a CPU
101b Main storage unit 101c Auxiliary storage unit 101d Input unit 101e Display unit 101f Interface unit 101g System bus 102 Surface potential meter 103 High voltage power supply device 104 Scanning device 105 Stage drive device 120 Substrate R Annular region

Claims (4)

An electron beam drawing apparatus for drawing a pattern on an object using an electron beam,
An insulator in which the cathode of the electron gun is disposed on the lower surface side;
A sensor electrode embedded in the vicinity of the lower surface of the insulator between the cathode and the outer edge of the insulator;
A potential measuring means for measuring the potential of the sensor electrode;
Control means for stopping drawing of the pattern on the object when it is determined that the potential of the sensor electrode is equal to or lower than a threshold based on the measurement result of the potential measuring means;
An electron beam drawing apparatus comprising: Blanking means for blanking the electron beam,
The control means, the potential of the sensor electrode, when it is determined that it is below the threshold, and controls the blanking means, electron beam lithography system according to claim 1 for blanking the electron beam. A power source for applying a voltage between the cathode and an anode disposed between the cathode and the object;
3. The electron beam drawing apparatus according to claim 2 , wherein when the control unit determines that the potential of the sensor electrode is equal to or lower than a threshold value, the control unit controls a power source to step down a voltage applied to the cathode. An electron beam drawing method for drawing a pattern on an object using an electron beam,
A step of measuring a potential of a sensor electrode embedded in the vicinity of the lower surface of the insulator between the outer edge of the insulator provided with the cathode of the electron gun on the lower surface side and the cathode;
Blanking the electron beam when the potential of the sensor electrode is below a threshold;
An electron beam drawing method including:

Images