JP5520161B2 - Electron gun conditioning method and electron beam drawing apparatus - Google Patents

Description

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

  In recent years, with the high integration and large capacity of large-scale integrated circuits (LSIs), the circuit line width required for semiconductor elements has become increasingly narrow and fine. A semiconductor element uses an original pattern (a mask or a reticle, hereinafter referred to as a mask) on which a circuit pattern is formed, and the pattern is exposed and transferred onto a wafer by a reduction projection exposure apparatus called a stepper. It is manufactured by forming a circuit. An electron beam drawing apparatus is used for manufacturing a mask for transferring such a fine circuit pattern onto a wafer.

  An electron gun that emits an electron beam is disposed in the electron beam drawing apparatus. When a high voltage is applied to the electron gun, abnormal discharge may occur due to discharge factors such as protrusions such as burrs and scratches on the electrode surface and deposits such as dust. Further, a large creeping discharge may occur due to a discharge factor caused by impurities or deposits on the insulator surface between the electrodes. The frequency of occurrence of such abnormal discharge is high at an initial stage such as about several tens of hours after the start of use of the electron gun after the installation or replacement of a new electron gun or after maintenance of the electron gun.

  When an abnormal discharge occurs in the electron gun, a voltage drop is caused in the high voltage source of the electron beam drawing apparatus and the operation is stopped. As a result, the operating rate of the electron beam drawing apparatus is lowered. In addition, since the electron beam that is originally necessary in the drawing process disappears, the drawing accuracy is lowered and the product yield is also lowered.

  Therefore, in order to suppress or prevent such abnormal discharge, a conditioning process is performed on the electron gun after a new electron gun is attached or replaced or after maintenance of the electron gun (for example, Patent Document 1). And 2). The conditioning treatment is effective in removing the discharge factor on the electrode surface and the insulator surface and improving the withstand voltage characteristics of the electron gun.

Japanese Patent Laying-Open No. 2005-026112 JP-A-3-133040

  However, the conventional conditioning method cannot sufficiently remove the minute protrusions, impurities or deposits that cause the minute discharge. For this reason, there has been a problem that abnormal discharge easily occurs due to the cause of such minute discharge during actual use of the electron gun.

  The present invention has been made in view of these problems. That is, an object of the present invention is to provide an electron gun conditioning method capable of effectively suppressing abnormal discharge of the electron gun.

  Another object of the present invention is to provide an electron beam lithography apparatus including a conditioning device that can effectively suppress abnormal discharge of an electron gun.

  Other objects and advantages of the present invention will become apparent from the following description.

According to a first aspect of the present invention, an acceleration voltage is applied between a cathode that emits electrons by heating, a Wehnelt to which a bias voltage is applied between the cathode and the cathode, and electrons emitted from the cathode are A method for conditioning an electron gun, in which a voltage is applied between the anode and Wehnelt to generate an electric discharge on these surfaces with respect to an electron gun having an anode that focuses to form an electron beam,
The application of the voltage between the anode and Wehnelt is performed by periodically changing the voltage within a range not exceeding the predetermined value after increasing the voltage to the predetermined value.
After a predetermined time has elapsed after confirming the stop of the discharge, the application of the voltage by periodically changing the voltage is stopped.

  In the first aspect of the present invention, the presence or absence of discharge is preferably detected by a change in pressure in the electron gun.

  In the first aspect of the present invention, it is preferable to change the voltage periodically by making the change when the voltage increases steep.

In the second aspect of the present invention, an acceleration voltage is applied between the cathode that emits electrons by heating, Wehnelt to which a bias voltage is applied between the cathode and the cathode, and the electrons emitted from the cathode are focused. An electron gun with an anode for forming an electron beam,
An electron beam drawing apparatus having a conditioning device for conditioning an electron gun,
Conditioning devices are those that apply a voltage between the anode and Wehnelt to cause discharge on these surfaces,
A supply for supplying voltage between the anode and Wehnelt;
An adjustment unit for adjusting a voltage supplied from the supply unit;
A control unit for controlling the adjustment unit,
The control unit periodically changes the voltage supplied from the supply unit to a predetermined value and periodically changes within a range not exceeding the predetermined value, and after a predetermined time has elapsed since the discharge was stopped. The adjustment unit is controlled so as to stop the application of the changed voltage.

The second aspect of the present invention has a detection unit for detecting the pressure in the electron gun,
The control unit can determine the presence or absence of discharge from the detection result of the detection unit.

  According to the first aspect of the present invention, there is provided an electron gun conditioning method capable of effectively suppressing abnormal discharge of the electron gun.

  According to the second aspect of the present invention, there is provided an electron beam lithography apparatus including a conditioning device that can effectively suppress abnormal discharge of an electron gun.

It is a figure which shows typically the structure of the electron gun in this Embodiment. It is a figure which shows the structure of the conditioning apparatus in this Embodiment. It is a flowchart which shows the conditioning method of this embodiment. It is a figure which shows the time change of the voltage and pressure which are applied to an electron gun in the conditioning method of this Embodiment. (A)-(c) is an example of the voltage waveform applied to an electron gun. It is a figure which shows the structure of the electron beam drawing apparatus of this Embodiment. It is explanatory drawing of the electron beam drawing method in this Embodiment.

  FIG. 1 is a diagram schematically showing a configuration of an electron gun in the present embodiment.

  As shown in FIG. 1, an electron gun 100 is disposed above an electron optical column 101, and includes a pair of first electrodes 102 (102a, 102b) and a column 103 as a second electrode. And Wehnelt (or extraction electrode) 104 as a third electrode.

During operation of the electron beam drawing apparatus, the inside of the electron gun 100 and the electron optical column 101 is in a high vacuum (for example, about 10 ⁻⁷ Pa). A high voltage (acceleration voltage) of about 50 kV, for example, is applied between the cathode 105 attached to the tip of the first electrode 102 and the anode 107. Thereby, the anode 107 focuses the electrons emitted from the cathode 105 to form an electron beam. In addition, a bias voltage for emitting a desired beam current to and from the cathode 105 is applied to the Wehnelt 104. For the cathode 105, for example, lanthanum hexaboride (LaB ₆ ) is used.

  When a voltage is applied between the first electrodes 102 a and 102 b, thermoelectrons are emitted from the cathode 105. The thermoelectrons are accelerated by the high voltage and are emitted into the electron optical column 101 as an electron beam 106. Thereafter, the electron beam 106 is shaped into a desired shape by various lenses, various deflectors, a beam shaping aperture (not shown) provided in the electron optical column 101, and then a mask to be drawn (see FIG. Irradiated to a desired position on (not shown).

  In the electron gun 100, the Wehnelt 104 is connected to the negative electrode side of the high voltage source 108, and the first electrode 102 is connected to the negative electrode side of the high voltage source 108 via the bias power source 109. Here, the Wehnelt 104 is higher than the first electrode 102 by, for example, about 500 V on the negative side. Further, the anode 107 and the column 103 are connected to the positive side of the high voltage source 108 and set to the ground potential. Here, although not shown, the first electrodes 102a and 102b, the column 103, and the Wehnelt 104 are insulated and separated by, for example, a ceramic insulator.

  When the above-described high voltage is applied to the electron gun 100, abnormal discharge caused by burrs, scratches, or other projections on the electrode surface, or dust or other deposits between the electrodes, in particular, between the anode 107 and the Wehnelt 104. Will occur. Alternatively, a large creeping discharge occurs due to discharge factors such as impurities and deposits on the surface of the insulator between the electrodes. The frequency of occurrence of such abnormal discharge is high at an initial stage such as several tens of hours after the start of use of the electron gun after the installation or replacement of a new electron gun or maintenance of the electron gun.

  Therefore, a conditioning process is performed to suppress or prevent such abnormal discharge. Hereinafter, an electron gun conditioning method according to the present embodiment will be described. In the present embodiment, it is preferable to carry out this conditioning method after installing or replacing a new electron gun, or after maintenance of the electron gun.

  FIG. 2 shows the configuration of the conditioning device in the present embodiment.

  In FIG. 2, the conditioning apparatus 200 performs conditioning of the electron gun 100. The conditioning apparatus 200 includes a voltage supply unit 11 as a voltage supply unit that supplies a high voltage to the electron gun 100, and a voltage adjustment unit 12 as a voltage adjustment unit that adjusts the voltage value of the voltage supply unit 11. The voltage adjustment unit 12 freely increases or decreases the output voltage of the voltage supply unit 11 according to a command from the control PC 17 described later. The connection unit 14 short-circuits the first electrode 102 and the Wehnelt 104 in FIG. 1, and a high negative voltage is applied to the first electrode 102 and the Wehnelt 104 from the voltage supply unit 11 by the connection unit 14.

The conditioning apparatus 200 includes a vacuum exhaust unit 15 and a pressure detection unit 16. The pressure detection unit 16 detects the pressure in the electron gun 100, and the vacuum exhaust unit 15 adjusts the inside of the electron gun 100 to a predetermined reduced pressure state. Here, the vacuum exhaust part 15 can be a vacuum exhaust apparatus provided with a vacuum pump such as an ion pump and a turbo molecular pump, and the degree of vacuum in the electron gun 100 can be controlled at a low pressure of 10 ⁻¹ Pa or less. Is preferred. Such an evacuation apparatus may be used also as an apparatus on which the electron gun 100 is mounted, for example, an evacuation apparatus used for depressurization of the electron optical column 101 in FIG. It may be provided as a vacuum exhaust device. On the other hand, the pressure detection unit 16 includes an ionization vacuum gauge such as a normal BA vacuum gauge, detects the degree of vacuum in the electron gun 100, and supplies the detected data to the control PC 17.

  The conditioning apparatus 200 includes, for example, a control personal computer (hereinafter referred to as a control PC) 17 as data processing means. The control PC 17 performs arithmetic processing using the detection value detected by the pressure detection unit 16 to control the vacuum exhaust unit 15 to make the inside of the electron gun 100 have a predetermined degree of vacuum, and also controls the voltage adjustment unit 12. Then, a predetermined voltage is supplied to the electron gun 100.

The control PC 17 can be a notebook personal computer, for example, and includes a microprocessor (MPU) to perform various data processing, and includes a memory unit, an input / output unit, and a display unit. The control PC 17 performs overall control related to the conditioning process of the electron gun 100. For example, based on the degree of vacuum in the electron gun 100 sent from the pressure detector 16, the evacuation unit 15 is controlled so that the degree of vacuum in the electron gun 100 becomes a constant pressure of about 10 ⁻⁵ Pa, for example. Control. In addition, the control PC 17 includes a timer inside, and controls the elapsed time of the conditioning process.

  FIG. 3 is a flowchart showing the conditioning method of the present embodiment. FIG. 4 is a diagram showing temporal changes in voltage and pressure applied to the electron gun 100 in this conditioning method.

  In the conditioning method in the present embodiment, a voltage is applied between the electrodes of the electron gun 100, specifically, between the anode 107 and the Wehnelt 104 by automatic control by the control PC 17. At this time, in the present embodiment, first, the applied voltage is increased to the conditioning voltage (S101). The increase in the applied voltage at this time can be a monotonic increase, that is, a linear function increase. Next, the value of the applied voltage is periodically changed within a range not exceeding the conditioning voltage (S102). As a result, a discharge is generated in the electron gun 100.

  In S102, for example, when the conditioning voltage is 80 kV, the amplitude of the applied voltage can be 10 kV and the period can be 1 second. That is, the applied voltage can be changed in a cycle of 1 second in the range of 70 to 80 kV. There is no particular limitation on the voltage waveform at this time, and any of the waveforms shown in FIGS. 5A to 5C can be used, for example. However, since discharge is more likely to occur as the voltage increases sharply, FIG. 5C is most preferable in the order of FIGS. 5C, 5A, and 5B.

  In S103, it is determined whether or not a discharge has occurred after changing the applied voltage. As shown in FIG. 4, when the applied voltage is increased to the conditioning voltage and then the voltage is periodically changed within a range not exceeding this voltage, a pressure change occurs in the electron gun 100. Thereby, it is detected that discharge has occurred in the electron gun 100. This pressure change can be detected by the pressure detection unit 16 in FIG.

  If it is determined in S103 that a pressure change has occurred, the determination is repeated until no discharge occurs. Then, even after it is determined in S103 that the discharge does not occur, the determination is repeated until the time t after the discharge does not occur exceeds a predetermined no-discharge time (for example, 1 hour) T.

  Whether or not the time t has passed the no-discharge time T is determined in S104. If it is determined that the no-discharge time T has not passed, the process returns to S103 and the same process is repeated. On the other hand, if it is determined in S104 that the time t has passed the no-discharge time T, the process proceeds to S105, and the routine for periodically changing the applied voltage is stopped. Thereafter, in S106, the applied voltage is set to 0 V, and a series of conditioning processes is completed.

  As described above, in the electron gun conditioning method according to the present embodiment, a voltage is applied between the anode and Wehnelt of the electron gun after installing or replacing a new electron gun or after maintenance of the electron gun. . At this time, after the voltage to be applied is monotonously increased to the conditioning voltage, the magnitude thereof is periodically changed in a range not exceeding the conditioning voltage. The conditioning voltage is higher than the voltage applied during actual use of the electron gun.

  Such a conditioning method is performed by the conditioning apparatus 200 described with reference to FIG. Here, the conditioning apparatus 200 applies a voltage between the anode and Wehnelt of the electron gun 100 to cause discharge on these surfaces. The conditioning device 200 includes a voltage supply unit 11 that supplies a voltage between the anode and Wehnelt, a voltage adjustment unit 12 that adjusts a voltage supplied from the voltage supply unit 11, and a control unit that controls the voltage adjustment unit 12. And a control PC 17. The control PC 17 periodically changes the voltage supplied to the electron gun 100 from the voltage supply unit 11 within a range not exceeding the predetermined value after increasing to a predetermined value (conditioning voltage value). The voltage adjustment unit 12 is controlled so as to stop the application of the voltage by periodically changing the voltage after a lapse of a predetermined time (for example, 1 hour) from the stop. In the conditioning apparatus 200 of FIG. 2, the pressure detection unit 16 detects the pressure in the electron gun 100, and the control unit PC 17 determines the presence or absence of discharge from the detection result of the pressure detection unit 16.

  As described above, by applying a voltage between the anode and Wehnelt, a discharge is induced in the electron gun, and a discharge factor on the electrode surface or the insulator surface is removed. The voltage application with the magnitude periodically changed is performed until it is confirmed that the discharge does not occur for a predetermined time. By doing so, it is possible to remove even a minute discharge factor that could not be sufficiently removed by the conventional conditioning method. Therefore, abnormal discharge due to such a micro discharge factor can be suppressed during actual use of the electron gun.

  Patent Document 2 describes that conditioning is performed by superimposing an AC power supply of 10 to 15 kV on a DC power supply of −50 kV. However, in patent document 2, the termination | terminus part by the side of an electron gun is made into the object of conditioning. On the other hand, this embodiment differs from Patent Document 2 in that a voltage is applied between the anode and Wehnelt of the electron gun to condition the surfaces of the anode and Wehnelt.

  FIG. 6 is a diagram mainly showing a configuration of a drawing control unit in the electron beam drawing apparatus according to the present embodiment. This electron beam drawing apparatus includes the electron gun and the conditioning device according to the present embodiment described with reference to FIGS. 1 and 2, and the electron gun conditioning method according to the present embodiment can be performed.

  In FIG. 6, a stage 33 on which a mask substrate 32 as a sample is installed is provided in a sample chamber 31 of the electron beam drawing apparatus 30. The stage 33 is driven by the stage drive circuit 34 in the X direction (left-right direction on the paper surface) and Y direction (vertical direction on the paper surface). The moving position of the stage 33 is measured by a position circuit 35 using a laser length meter or the like.

  An electron beam optical system 40 is installed above the sample chamber 31. The electron beam optical system 40 includes an electron gun 100 according to the present embodiment, various lenses 37, 38, 39, 41, 42, a blanking deflector 43, a shaping deflector 44, a main deflector 45 for beam scanning, It comprises a sub-deflector 46 for beam scanning, two beam shaping apertures 47 and 48, and the like.

  The electron gun 100 corresponds to the electron gun 100 of FIG. 1 and is connected to the conditioning device 200 of FIG. Thus, the electron beam drawing apparatus 30 can condition the electron gun 100. That is, a voltage is applied between the anode and Wehnelt of the electron gun 100 to induce a discharge in the electron gun 100. The voltage to be applied is monotonically increased to the conditioning voltage, and then the magnitude is periodically changed within a range not exceeding the conditioning voltage. This operation is performed until it is confirmed that the discharge does not occur for a predetermined time. As a result, even a minute discharge factor can be removed, so that abnormal discharge caused by the minute discharge factor can be suppressed when the electron gun 100 is actually used.

  FIG. 7 is an explanatory diagram of an electron beam drawing method according to the present embodiment. This drawing method is realized by using the electron beam drawing apparatus 30 of the present embodiment. That is, the electron beam 20 shown in FIG. 7 is an electron beam emitted by the electron gun 100 of the electron beam drawing apparatus 30 of the present embodiment.

  As shown in FIG. 7, the pattern 81 drawn on the mask substrate 32 is divided into strip-shaped frame regions 82. Drawing with the electron beam 20 emitted by the electron gun 100 of the electron beam drawing apparatus 30 is performed for each frame region 82 while the stage 33 continuously moves in one direction (for example, the X direction). The frame area 82 is further divided into sub-deflection areas 83, and the electron beam 20 draws only necessary portions in the sub-deflection areas 83. The frame area 82 is a strip-shaped drawing area determined by the deflection width of the main deflector 45, and the sub-deflection area 83 is a unit drawing area determined by the deflection width of the sub-deflector 46.

  The positioning of the electron beam 20 in the sub deflection region 83 is performed by the sub deflector 46. The position of the sub deflection region 83 is controlled by the main deflector 45. That is, the main deflector 45 positions the sub deflection region 83, and the sub deflector 46 determines the beam position in the sub deflection region 83. Further, the shape and size of the electron beam 20 are determined by the shaping deflector 44 and the beam shaping apertures 47 and 48. Then, the sub-deflection area 83 is drawn while continuously moving the stage 33 in one direction. When drawing of one sub-deflection area 83 is completed, the next sub-deflection area 83 is drawn. When drawing of all the sub deflection areas 83 in the frame area 82 is completed, the stage 33 is moved stepwise in a direction orthogonal to the direction in which the stage 33 is continuously moved (for example, the Y direction). Thereafter, similar processing is repeated, and the frame area 82 is sequentially drawn.

  When performing drawing with an electron beam, first, pattern data (CAD data) such as a semiconductor integrated circuit designed by using a CAD system can be input to the electron beam drawing apparatus 30 in FIG. Converted to (layout data). Next, after the layout data is converted and drawing data is created, the drawing data is divided into a size at which the electron beam 20 is actually shot, and then drawing is performed for each shot size.

  The drawing data converted from the layout data is recorded in the input unit 51 which is a storage medium, read by the control computer 50, and temporarily stored in the pattern memory 52 for each frame area 82. The pattern data for each frame area 82 stored in the pattern memory 52, that is, the frame information composed of the drawing position, the drawing graphic data, etc. is sent to the pattern data decoder 53 and the drawing data decoder 54 which are data analysis units. Next, the sub-deflection area deflection amount calculation unit 60, the blanking circuit 55, the beam shaper driver 56, the main deflector driver 57, and the sub-deflector driver 58 are sent via these.

  In addition, a deflection control unit 62 is connected to the control computer 50. The deflection control unit 62 is connected to the settling time determination unit 61, the settling time determination unit 61 is connected to the sub deflection region deflection amount calculation unit 60, and the sub deflection region deflection amount calculation unit 60 is connected to the pattern data decoder 53. doing. Further, the deflection control unit 62 is connected to the blanking circuit 55, the beam shaper driver 56, the main deflector driver 57, and the sub deflector driver 58.

  Information from the pattern data decoder 53 is sent to a blanking circuit 55 and a beam shaper driver 56. Specifically, the pattern data decoder 53 creates blanking data based on the drawing data and sends it to the blanking circuit 55. Further, desired beam dimension data is also created based on the drawing data, and is sent to the sub deflection region deflection amount calculation unit 60 and the beam shaper driver 56. Then, a predetermined deflection signal is applied from the beam shaper driver 56 to the shaping deflector 44 of the electron beam optical system 40 to control the shape and size of the electron beam 20.

  The sub deflection region deflection amount calculation unit 60 calculates the deflection amount (movement distance) of the electron beam for each shot in the sub deflection region 83 from the beam shape data created by the pattern data decoder 53. The calculated information is sent to the settling time determination unit 61, and the settling time corresponding to the movement distance by the sub deflection is determined.

  The settling time determined by the settling time determination unit 61 is sent to the deflection control unit 62, and then the blanking circuit 55, the beam shaper driver 56, the main shaper 56 It is appropriately sent to either the deflector driver 57 or the sub deflector driver 58.

  The drawing data decoder 54 creates positioning data for the sub deflection region 83 based on the drawing data, and sends this data to the main deflector driver 57 and the sub deflector driver 58. Then, a predetermined deflection signal is applied from the main deflector driver 57 to the main deflector 45 of the electron beam optical system 40, and the electron beam 20 is deflected and scanned to a predetermined main deflection position. In addition, a predetermined sub deflection signal is applied from the sub deflector driver 58 to the sub deflector 46 and drawing in the sub deflection region 83 is performed. Specifically, this drawing is performed by repeatedly irradiating the electron beam 20 after a settling time has elapsed.

  As described above, the electron beam drawing apparatus according to the present embodiment includes the conditioning apparatus that can perform the electron gun conditioning method according to the present embodiment. Therefore, it is possible to induce a discharge in the electron gun by applying a voltage between the anode and Wehnelt of the electron gun. At this time, the voltage to be applied is monotonically increased to the conditioning voltage, and then the magnitude thereof is periodically changed within a range not exceeding the conditioning voltage. This operation is performed until it is confirmed that the discharge has not occurred for a predetermined time. As a result, even a minute discharge factor can be removed, so that abnormal discharge due to the minute discharge factor can be caused during actual use of the electron gun. Therefore, it is possible to improve the product yield by suppressing the operation stop of the electron beam drawing apparatus due to the abnormal discharge of the electron gun and the reduction in drawing accuracy due to the disappearance of the electron beam originally necessary in the drawing process.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, although the electron beam is used in the above embodiment, the present invention is applied to a charged particle gun conditioning method using another charged particle beam such as an ion beam, and a charged particle beam drawing apparatus including the charged particle gun. Is also applicable.

DESCRIPTION OF SYMBOLS 11 Voltage supply part 12 Voltage adjustment part 14 Connection part 15 Vacuum exhaust part 16 Pressure detection part 17 Control PC
DESCRIPTION OF SYMBOLS 100 Electron gun 101 Electron optical column 102, 102a, 102b 1st electrode 103 Column 104 Wehnelt 105 Cathode 106 Electron beam 107 Anode 108 High voltage source 109 Bias power supply 200 Conditioning device 20 Electron beam 30 Electron beam drawing device 31 Sample chamber 32 Mask substrate 33 Stage 34 Stage drive circuit 35 Position circuit 37, 38, 39, 41, 42 Various lenses 40 Electron beam optical system 43 Blanking deflector 44 Molding deflector 45 Main deflector 46 Sub deflector 47, 48 Beam shaping Aperture 50 Control computer 51 Input section 52 Pattern memory 53 Pattern data decoder 54 Drawing data decoder 55 Blanking circuit 56 Beam shaper driver 57 Main deflector driver 58 Sub deflector door Driver 60 Sub deflection region deflection amount calculation unit 61 Settling time determination unit 62 Deflection control unit 81 Pattern to be drawn 82 Frame region 83 Sub deflection region

Claims (5)

An acceleration voltage is applied between the cathode that emits electrons by heating, a Wehnelt to which a bias voltage is applied between the cathode and the cathode, and the electrons emitted from the cathode are focused to form an electron beam. A method for conditioning an electron gun, wherein a voltage is applied between the anode and the Wehnelt to generate an electric discharge on the surface of the electron gun including an anode to be formed,
The application of the voltage between the anode and the Wehnelt is performed by periodically changing the voltage within a range not exceeding the predetermined value after increasing the voltage to a predetermined value,
A method for conditioning an electron gun, wherein the application of the voltage is stopped by periodically changing the voltage after a predetermined time has elapsed after confirming the stop of the discharge.   2. The method for conditioning an electron gun according to claim 1, wherein the presence or absence of the discharge is detected by a pressure change in the electron gun.   3. A method for conditioning an electron gun according to claim 1, wherein the voltage is periodically changed by making the change when the voltage increases steep. A cathode that emits electrons by heating, Wehnelt to which a bias voltage is applied between the cathode and an acceleration voltage is applied between the cathode and the electrons emitted from the cathode are focused to form an electron beam. An electron gun with an anode;
An electron beam lithography apparatus having a conditioning device for conditioning the electron gun,
The conditioning device applies a voltage between the anode and the Wehnelt to cause discharge on these surfaces,
A supply for supplying a voltage between the anode and the Wehnelt;
An adjustment unit for adjusting a voltage supplied from the supply unit;
A control unit for controlling the adjustment unit,
The control unit is configured to periodically change the voltage supplied from the supply unit within a range not exceeding the predetermined value after increasing to a predetermined value, and after a predetermined time has elapsed from the stop of the discharge. The electron beam lithography apparatus is characterized in that the adjustment unit is controlled to stop the application of the voltage by periodically changing the voltage. A detector for detecting pressure in the electron gun;
The electron beam drawing apparatus according to claim 4, wherein the control unit determines the presence or absence of the discharge from a detection result of the detection unit.

Images