JP2001118767A - Device for cleaning inside of lens barrel of electron beam plotting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device capable of surely cleaning the inside of the lens barrel of an electron beam plotting device by a remote operation by using etching gas containing a radical. SOLUTION: This device 30 for cleaning the inside of the lens barrel is attached to the lens barrel 10 through a gate valve 34. For an electric discharge tube 40, a tip is attached to the gate valve 34 and a cleaning gas supplier 45 is connected to a rear end. The discharge tube 40 is passed through the cavity of a microwave generator 48 and the periphery is covered with a light shielding cover 47. A photoelectric sensor 50 is housed in the light shielding cover 47 and a Tesla coil 49 is arranged adjacent to the light shielding cover 47. A control part 62 operates the respective pieces of equipment, starts discharge inside the discharge tube 40, and supplies the etching gas containing the radial into the lens barrel 10. When the discharge is not started, the control part 62 repeats a discharge starting operation by receiving detection signals from the photoelectric sensor 50 and re-operating the Tesla coil 49.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam lithography system, and more particularly to a cleaning in a lens barrel for etching and removing deposits attached to the surface of a component such as a beam deflector installed in the lens barrel. Related to the device.

[0002]

2. Description of the Related Art When an electron beam drawing apparatus is used continuously for a long time, deposits adhere to components provided in a lens barrel, especially to a beam deflector. Of the sediment thus attached,
Since a charge is generated in an insulating material (insulating film),
This causes drift of the electron beam and causes deterioration of the drawing accuracy.

To cope with such a problem, Japanese Patent Laid-Open No.
No. 39010 discloses a cleaning gas (for example, in a discharge tube).
The mixture gas of O ₂ and CF ₄ ) is irradiated with microwaves to generate radicals, and an etching gas containing radicals (free radicals) is flowed into the lens barrel to etch deposits attached to the surface of the component. An in-lens cleaning device that removes by removal is described.

The above-mentioned cleaning device in the lens barrel needs to be shielded from the inside of the lens barrel at the time of drawing, and is connected to the side wall of the lens barrel via a gate valve. Therefore, when cleaning the inside of the lens barrel, it is necessary to open and close the gate valve. Further, since it is relatively difficult to cause a discharge in the cleaning gas in the discharge tube by the microwave, the operation is complicated, for example, it is necessary to confirm the occurrence of the discharge.
Further, in the electron beam lithography apparatus, it is necessary to minimize the approach of a person to the apparatus in order to prevent drawing failure due to dust.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the conventional cleaning apparatus in a lens barrel using an etching gas containing radicals as described above. An object of the present invention is to provide a cleaning device in a lens barrel of an electron beam lithography apparatus which can be reliably performed by remote operation.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided an in-lens cleaning apparatus for an electron beam lithography apparatus, in which an etching gas containing radicals is flowed into a lens barrel of an electron beam lithography apparatus to remove components disposed inside. In the in-barrel cleaning apparatus for cleaning, a gate valve attached to a side wall of the barrel, a glass discharge tube whose tip is connected to the barrel via the gate valve, and a rear end of the discharge tube A cleaning gas supply device for supplying a cleaning gas into the discharge tube, a microwave generation terminal, and a matching tab, wherein the discharge tube penetrates a cavity therebetween, and the cleaning gas flows through the discharge tube. A microwave generator that generates a discharge within the microwave generator to generate radicals; and a microwave generator that is disposed adjacent to the microwave generator and that extends from outside to inside of the discharge tube. A Tesler coil that starts a discharge in the discharge tube by emitting a strong microwave pulse, a sensor for detecting that the discharge tube is in a discharge state, the cleaning gas supply device, and the gate A control unit for controlling the bulb, the microwave generator, and the Tesler coil, respectively, to start and end the discharge in the discharge tube, wherein the control unit is determined in advance from the operation of the Tesler coil. When the sensor does not confirm that the inside of the discharge tube is in a discharge state after a lapse of time, the Tesler coil is operated again.

According to the in-lens cleaning device of the present invention, the gas supply device, the gate valve, the microwave generator, and the Tesler coil are automatically operated in accordance with a predetermined sequence based on a command from the control unit, and automatically. Initiate the discharge in the cleaning gas. If no discharge occurs, the sensor detects this, and based on the result, activates the Tesler coil again to start discharge. Such a restart of the Tesler coil is repeatedly performed a predetermined number of times until the discharge state is confirmed by the sensor.

Preferably, when the discharge state is not confirmed before the number of times of re-operation of the Tesler coil reaches a preset upper limit number, the control unit operates the gas supply device and the microwave generation device. Is stopped and the gate valve is closed.

Preferably, a photoelectric sensor is used as the sensor, and the periphery of an intermediate portion of the discharge tube is covered with a light-shielding cover, and the cavity portion of the microwave generator and the sensor are accommodated in the light-shielding cover.

[0010] Preferably, the light-shielding cover is configured so that the inside thereof can be exhausted.

Preferably, the gate valve is mounted on a side wall of a lens barrel via a flange, and the discharge tube and the gate valve are arranged such that their axes are aligned. With this configuration, the radical generated in the cleaning gas by the microwave generator can be efficiently sent into the lens barrel.

Preferably, the microwave generator and the Tesler coil are supported by a base plate made of an electrically insulating material, and the base plate is fixed to a lens barrel. With this configuration, it is possible to prevent the microwave generator and the Tesler coil from applying electric or magnetic noise to the electron beam writing apparatus main body.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of an in-lens cleaning apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of an electron beam lithography system equipped with an in-lens cleaning device according to the present invention.
In the figure, reference numeral 10 denotes a lens barrel of the electron beam writing apparatus, in which an electron beam generator 11, various electron lenses 12,
13, 14, 15, first aperture 16 and second aperture 17 for variable shaping beam, beam shaping deflector 18
a, 18b, a beam position control deflector 19, and the like. A drawing chamber 20 is provided below the lens barrel 10,
An XY stage 22 is provided therein. The workpiece 21 is held on an XY stage 22. The cleaning device 30 in the lens barrel according to the present invention includes the first aperture 1 of the lens barrel 10.
At a position corresponding to between the electronic lens 6 and the electronic lens 13, the electronic lens 13 is attached to the lens barrel 10 via a gate valve 34.

In this electron beam drawing apparatus, the electron beam emitted from the electron beam
The electron beam is focused on the first aperture 16 by 2 to form an electron beam having a predetermined sectional shape. This is the electronic lens 1
The electron beam is focused on the second aperture 17 by 3 and 14 and deflected by the beam shaping deflectors 18a and 18b to obtain an electron beam having a desired cross-sectional shape. This is focused on the drawing material 21 by the electron lens 15, and the electron beam is guided onto the drawing material 21 by the beam position control deflector 19, and a predetermined pattern is drawn on the drawing material 21. .

The configuration itself of the main body of the electron beam lithography apparatus is not the subject of the present invention, and may be in various known forms. For this reason, only the outline is shown and detailed description is omitted.

FIG. 2 shows an axial sectional view of a main part of the in-lens cleaning device 30. The in-lens cleaning device 30 includes a gate valve 34, a discharge tube 40, a cleaning gas supply device 45, a microwave generator 48, a Tesler coil 49, and a photoelectric sensor 5
0 (sensor) and the like.

A flange 31 is fixed to a side wall of the lens barrel 10 by a bolt 32. A gate valve 34 is fixed to the rear surface (left side surface in FIG. 2) of the flange 31 by bolts 33. A base plate 5 made of an electrically insulating material (for example, a resin such as vinyl chloride) is further provided on the back surface of the flange 31 via a bracket 56.
5 is attached.

The gate valve 34 is attached to the lens barrel 10 via the flange 31. The flange 31 has a hole 35 penetrating front and rear at the center thereof. The hole 35 communicates with the through hole 36 on the outlet side of the gate valve 34 in a straight line, and a nozzle 37 for gas introduction is attached to the lens tube 10 side of the hole 35. Gate valve 3
4 is a pneumatic type, which is automatically opened and closed by a pneumatic cylinder (not shown).

A distal end of a discharge tube 40 made of quartz glass is hermetically attached to a through hole 38 on the inlet side of the gate valve 34 via a joint 39. The discharge tube 40 is disposed so as to communicate with the through hole 38 in a straight line.

A cleaning gas supply device 45 is hermetically connected to the rear end of the discharge tube 40 via a joint 43 and a pipe joint 44. The joint 43 is supported on a front end portion (left end in FIG. 2) of the base plate 55 via a bracket 57.

Near the center of the base plate 55, a light-shielding cover 47 is mounted via a mounting base 46.
The light shielding cover 47 is provided so as to cover the periphery of the middle part of the discharge tube 40. The cavity portion of the microwave generator 48 is accommodated in the light shielding cover 47. The microwave generator 48 includes a pair of microwave generating terminals 48a and a matching tab 48b for adjustment.
The discharge tube 40 passes through a cavity (resonant cavity) formed between them. Further, a photoelectric sensor 50 for detecting the presence or absence of a discharge in the discharge tube 40 is accommodated in the light shielding cover 47. Shading cover 4
7 is connected to a pipe 47a for exhausting ozone gas and the like generated by microwaves.

Further, adjacent to the light shielding cover 47, along the discharge tube 40 and upstream of the microwave generator 48,
A Tesler coil 49 is provided. The Tesler coil 49 is also supported on the base plate 55.

FIG. 3 is a sectional view taken along line AA of FIG. As shown in FIG. 3, the tip of the terminal 49 a of the Tesler coil 49 is directed to the central axis of the discharge tube 40, and emits a stronger microwave pulse than the microwave generator 48.
The discharge is started in the discharge tube 40. In the light shielding cover 47, as described above, the photoelectric sensor 50 is provided.
Is housed.

FIG. 4 shows a control block diagram of the cleaning device in the lens barrel. The cleaning gas supply device 45, the gate valve 34, the microwave generator 48, and the Tesler coil 49 are controlled according to a command from the control unit 62. The control unit 62
Upon receiving a cleaning start signal from the operation unit 61, the above devices are operated in accordance with a predetermined sequence to start discharge in the discharge tube 40 and to supply an etching gas containing radicals into the lens barrel 10. . Similarly, the control unit 62
Receives the cleaning completion signal from the operation unit 61, stops the discharge in the discharge tube 40, and stops the supply of the cleaning gas into the lens barrel 10. As described later, when no discharge occurs in the discharge tube 40, the control unit 62
Controls the operation of the Tesler coil 49 in response to the detection signal from the photoelectric sensor 50 to repeat the discharge start operation.

FIG. 5 shows a flowchart of the control by the control unit 62. (A) is a flow for starting the cleaning,
(B) is a flow at the end of cleaning.

When it is determined from the accumulated drawing time and the drift amount of the electron beam that cleaning of the lens barrel is necessary, the drawing operation is interrupted, and a command signal for starting the cleaning is sent from the operation unit 61 (FIG. 4) to the control unit 62. give. In response to the command signal, the control unit 62 executes the cleaning start flow shown in FIG. 5A, and operates the cleaning gas supply device 45, the gate valve 34, the microwave generator 48, and the Tesler coil 49.

That is, first, the supply of the cleaning gas from the cleaning gas supply device 45 is started (step ST1). Then
The gate valve 34 is opened (step ST2). Thereby, the cleaning gas (for example, a mixed gas of O ₂ and CF ₄ )
From the cleaning gas supply device 45 to the discharge tube 40 and the gate valve 3
The light is sent into the lens barrel 10 through the nozzle 4 and the nozzle 37 in order.

In this state, the microwave generator 48 is operated (step ST3). Note that no discharge occurs in the discharge tube 40 only by the operation of the microwave generator 48. In the next step (step ST4), the discharge is generated by operating the Tesler coil 49, and thereafter, the discharge state is maintained by the microwave generator 48. The discharge state of the microwave generator 48 is detected by the photoelectric sensor 50. However, the start of the discharge by the Tesler coil 49 or the maintenance of the discharge state by the microwave generator 48 following this may fail. Therefore, the Tesler coil 49
After the operation of (1), after waiting for 2 to 3 seconds (step ST5), the discharge state in the discharge tube 50 is confirmed using the photoelectric sensor 50.

As a result, if the discharge state is not maintained in the discharge tube 50, the process returns to step ST4, and
The Tesler coil 49 is operated to start discharging.
Such operation of reactivating the Tesler coil 49 is repeatedly performed until the photoelectric sensor 50 confirms the discharge state.

If the discharge is not confirmed even after the Tesler coil 49 is restarted a predetermined number of times, it is possible that the device has malfunctioned such as breakage of the discharge tube 40. The operation of the wave generator 48 and the cleaning gas supply device 45 is stopped, and the gate valve 3 is stopped.
Close 4. On the other hand, when the discharge state is confirmed in step ST6, the start of radical generation is displayed (step ST7), and the cleaning start flow ends.

The discharge in the cleaning gas in the discharge tube 40 generates radicals in the cleaning gas, and the etching gas containing the radicals passes through the gate valve 34 and the flange 31 from the nozzle 37 into the lens barrel 10. Supplied. The etching gas containing radicals flows along components such as the beam shaping deflectors 18a and 18b (FIG. 1), and after etching the insulating film and the like deposited on the surfaces thereof, exhaust gas 25 (FIG. 1). ) Is discharged through.

At this time, the position where radicals are generated, that is, the discharge tube 4 penetrating the cavity of the microwave generator 48
0 (discharge position) through the short and straight path of only the gate valve 34 and the flange 31,
The cleaning gas having a high radical density is supplied into the lens barrel 10 with little deactivation of the generated radicals.

After the cleaning process in the lens barrel 10 (FIG. 1) is completed in this manner, the operation unit 61 (FIG. 4) controls the control unit 62.
To the cleaning end command signal. In response to the command signal, the control unit 62 executes the cleaning end flow shown in FIG. That is, upon receiving the cleaning end command signal from the operation unit 61, the microwave generator 48 is stopped (step S).
T11) Then, the supply of the cleaning gas from the cleaning gas supply device 45 is stopped (step ST12), and the gate valve 34 is closed (step ST13).

The cleaning end flow is shown in FIG.
The time elapsed from step ST7 shown in FIG.
The program may be automatically executed based on analysis data of gas discharged from (FIG. 1).

The above-described cleaning operation in the lens barrel itself is performed with the drawing stopped, so that the drawing accuracy is not adversely affected. However, the microwave generator 48 and the Tesler coil 49 are both grounded, and the lens barrel 10 is also grounded (not shown). Unless electrically insulated, an electric circuit connecting them is formed, and even when the microwave generator 48 and the Tesler coil 49 are not operated, electric or magnetic noise may be applied to the electron beam writing apparatus main body. is there. Therefore, in the example shown in FIG. 2, the microwave generator 48 and the Tesler coil 49
Is supported on a base plate 55 made of an electrically insulating material (for example, vinyl chloride), and the base plate 55 is attached to the lens barrel 10 via a bracket 56. Therefore, the microwave generator 48 and the Tesler coil 49
However, there is no fear that electric or magnetic noise is given to the electron beam writing apparatus main body.

[0037]

According to the apparatus for cleaning the inside of a lens barrel according to the present invention, the cleaning operation of the inside of the lens barrel with an etching gas containing radicals can be reliably performed by remote control.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the configuration of an electron beam writing apparatus to which an in-lens cleaning device according to the present invention is attached.

FIG. 2 is a detailed diagram showing a configuration of a main part of the in-lens cleaning device according to the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a control block diagram of the in-lens cleaning device according to the present invention.

FIGS. 5A and 5B are control flowcharts of the in-lens cleaning device according to the present invention, wherein FIG. 5A is a flow for starting cleaning, and FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Barrel, 11 ... Electron beam generation part, 12, 13, 14, 15 ... Electron lens, 16 ... 1st aperture, 17 ... 2nd aperture, 18a, 18b ... -Beam forming deflector, 19-Beam position controlling deflector, 20-Drawing chamber, 21-Material to be drawn, 22-XY stage, 25-Exhaust port, 30-・ In-cylinder cleaning device, 31 ・ ・ ・ Flange, 34 ・ ・ ・ Gate valve, 37 ・ ・ ・ Nozzle, 39 ・ ・ ・ Fitting part, 40 ・ ・ ・ Discharge tube, 43 ・ ・ ・ Fitting, 44 ・ ・ ・Pipe fittings, 45 ... Gas supply device, 46 ... Mounting stand, 47 ... Light shielding cover, 47a ... Pipe (for exhaust), 48 ... Microwave generator, 48a ... Micro Wave generating terminal, 48b ... matching tab, 49 ... test Koiru, 50 ... photoelectric sensor (sensor), 55 ... base plate, 56 ... bracket, 57 ... bracket, 61 ... operation part, 62 ... control unit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference)

Claims (6)

[Claims] 1. An in-lens cleaning apparatus for cleaning a component disposed therein by flowing an etching gas containing radicals into a lens barrel of an electron beam writing apparatus, wherein the gate is attached to a side wall of the lens barrel. A bulb, a glass discharge tube having a distal end connected to the lens barrel via the gate valve, a cleaning gas supply device connected to a rear end of the discharge tube, and supplying a cleaning gas into the discharge tube; A microwave generation device having a microwave generation terminal and a matching tab, wherein the discharge tube penetrates a cavity between them, and causes a discharge in a cleaning gas flowing in the discharge tube to generate radicals; The discharge device is arranged adjacent to the microwave generator and emits a microwave pulse that is stronger than the microwave generator from outside to inside of the discharge tube. A Tesler coil for starting discharge in the tube, a sensor for detecting that the inside of the discharge tube is in a discharge state, and controlling the cleaning gas supply device, the gate valve, the microwave generator, and the Tesler coil, respectively. A control unit that starts and ends the discharge in the discharge tube.The control unit may be in a discharge state after a predetermined time has elapsed since the operation of the Tesler coil. The in-cylinder cleaning device of the electron beam writing apparatus, wherein the device is configured to operate the Tesler coil again when it is not confirmed by the sensor. 2. The cleaning gas supply device and the microwave generation device, when the discharge state is not confirmed before the number of times of re-operation of the Tesler coil reaches a preset upper limit number. 2. The apparatus according to claim 1, wherein the operation of the apparatus is stopped and the gate valve is closed. 3. The sensor according to claim 1, wherein the sensor is a photoelectric sensor, and a periphery of an intermediate portion of the discharge tube is covered with a light-shielding cover, and the cavity portion of the microwave generator and the sensor are accommodated in the light-shielding cover. 2. The cleaning apparatus according to claim 1, wherein the cleaning apparatus includes a cleaning unit. 4. The cleaning device according to claim 3, wherein the light shielding cover is configured to be able to exhaust the inside. 5. The gate valve is mounted on a side wall of a lens barrel via a flange, and the discharge tube and the gate valve are arranged such that their axes are aligned. An apparatus for cleaning the inside of a lens barrel of an electron beam lithography apparatus according to claim 1. 6. The electronic device according to claim 1, wherein the microwave generator and the Tessler coil are supported by a base plate made of an electrically insulating material, and are attached to a lens barrel via the base plate. Cleaning device in the lens barrel of the beam drawing device.