JP4299618B2 - Gas cluster ion beam system - Google Patents

Description

  The present invention relates to a gas cluster ion beam apparatus.

  2. Description of the Related Art Conventionally, there is known a processing method for obtaining a flat surface by irradiating a surface of a workpiece such as a substrate with a gas cluster ion beam and polishing the surface (see, for example, Patent Document 1).

  FIG. 2 is a schematic configuration diagram showing a general conventional gas cluster ion beam apparatus that irradiates a gas cluster ion beam. The gas cluster ion beam apparatus includes a vacuum chamber 3 having a nozzle chamber 1 for generating a neutral gas cluster and an ionization chamber 2 for ionizing and accelerating the gas cluster. The ionization chamber 2 is separated by a partition wall 5 to which a skimmer 4 is attached. The nozzle chamber 1 and the ionization chamber 2 are each maintained in vacuum by a vacuum pump (not shown).

  The nozzle chamber 1 has a conical nozzle 6, and the ionization chamber 2 has an ionization portion 7 and an extraction electrode 8. The ionization part 7 is comprised by the cage | basket-shaped anode 9 and the filament 10 which consists of the tungsten fine wire arrange | positioned concentrically on the outer periphery. The extraction electrode 8, the anode 9, and the filament 10 are supported in the ionization chamber 2 by a support member (not shown).

  A source gas supplied from a gas cylinder (not shown) is ejected at supersonic speed by the nozzle 6 in the nozzle chamber 1 to generate a gas cluster by adiabatic expansion. Part of the generated gas cluster passes through the skimmer 4 and is supplied to the ionization chamber 2 with the beam shape adjusted.

  In the ionization section 7 of the ionization chamber 2, the thermoelectrons emitted from the heated filament 10 by applying a voltage from the filament power supply 11a are accelerated by the anode 9 to which a voltage is applied from the ionization power supply 11b, and collide with a gas cluster. Ionize the gas cluster beam. The ionized gas cluster beam is accelerated by an electric field formed between the anode 9 and the extraction electrode 8 by the acceleration power source 12. Then, the accelerated gas cluster beam is caused to collide with the surface of the workpiece 13 such as the front substrate.

  At this time, the constituent atoms or molecules of the cluster cause a multi-body collision with the constituent atoms or molecules of the workpiece 13. As a result, the constituent atoms of the workpiece 13 move laterally on the surface. Thereby, the convex part of the surface of the to-be-processed object 13 is shaved, and polishing by atomic size is attained, and a flat surface can be obtained.

  Incidentally, in the ionization chamber 2 of the conventional gas cluster ion beam apparatus shown in FIG. 2, it is necessary to apply a high voltage (several tens of kV) between the anode 9 and the extraction electrode 8 in order to accelerate the ionized gas cluster beam. As a result, the ionization chamber 2 is maintained in vacuum by a vacuum pump (not shown). The nozzle chamber 1 is also maintained in a vacuum by a vacuum pump (not shown) in order to generate a neutral gas cluster. The ionization chamber 2 is set to a vacuum with a lower pressure than the nozzle chamber 1.

For this reason, the nozzle chamber 1 and the ionization chamber 2 are separated by the partition wall 5 having the skimmer 4 attached to the center so that only the neutral gas cluster flows into the ionization chamber 2 through the skimmer 4. The partition wall 5 provided between the nozzle chamber 1 and the ionization chamber 2 is fixed to the outer surface of the vacuum vessel 3 with bolts (not shown) via an O-ring (not shown).
JP-A-8-120470

  By the way, in the conventional gas cluster ion beam apparatus shown in FIG. 2, it is necessary to periodically perform maintenance work on the ionization section (anode 9 and filament 10) 7 and the extraction electrode 8 in the ionization chamber 2 in accordance with the operation state. is there.

  For this reason, conventionally, when performing the maintenance work of the ionization section 7 and the extraction electrode 8 in the ionization chamber 2, the partition wall 5 which is bolted is removed and the nozzle chamber 1 and the ionization chamber 2 are separated and removed. Later, workability was poor by removing the ionization section 7 and the extraction electrode 8 in the ionization chamber 2.

  In addition, when replacing the removed ionization section 7 and the extraction electrode 8 with new ones, the installation work is complicated by performing the installation work in the ionization chamber 2, and the nozzle 6, the skimmer 4 after assembly, The centering of the ionization part 7 and the extraction electrode 8 also took time.

  Therefore, the present invention makes it possible to easily replace the ionization section and extraction electrode in the ionization chamber during maintenance work, and even when the removed ionization section and extraction electrode are replaced with new ones, the nozzle, skimmer, and ionization section Another object of the present invention is to provide a gas cluster ion beam apparatus that can easily center the extraction electrode.

In order to achieve the above object, the present invention separates the nozzle chamber from the nozzle chamber by generating a neutral gas cluster by ejecting the introduced gas from the nozzle at a high speed, and separating the nozzle into the partition. An ionization chamber provided with an ionization chamber that is supplied after being adjusted to a beam shape by a provided skimmer is provided, and an ionization unit that ionizes the gas cluster adjusted to the beam shape in the ionization chamber, and ionization by the ionization unit A gas cluster ion beam apparatus having an acceleration electrode system for accelerating the irradiated gas cluster arranged in the beam shape and irradiating the surface of the workpiece, wherein the nozzle chamber and the ionization chamber are respectively are individually connected to the exhaust system, the partition with is placed slidably in said vacuum chamber, said partition wall opposed to previous A vacuum vessel side plate provided with a nozzle is detachably fixed to the vacuum vessel, and supports the ionization part and the acceleration electrode system on the partition wall, and supports the partition wall on the vacuum vessel side plate with a support member, Furthermore, the power supply wiring to the ionization part is connected to the ionization part while maintaining electrical insulation between the vacuum vessel side plate and the partition wall.

  In addition, the partition wall is installed with a gap from the inner peripheral surface of the vacuum vessel. The gap between the partition wall and the inner peripheral surface of the vacuum container may be such that part of the edge of the partition wall is in contact with the inner peripheral surface of the vacuum container, and the entire edge of the partition wall is in contact with the inner peripheral surface of the vacuum container. You may provide so that it may not.

  The gap has a conductance value of 10 l / sec or less.

  According to the gas cluster ion beam apparatus of the present invention, the ionization part and the extraction electrode can be detached from the vacuum container integrally with the partition wall by the operation of removing the vacuum container side plate from the vacuum container. It is possible to easily exchange with good workability, and maintenance work can be easily performed in a short time.

  In addition, when the ionization part and the extraction electrode are exchanged outside the vacuum vessel and replaced with a new one, the nozzle, skimmer, ionization part and extraction electrode can be easily centered after maintenance work. it can.

  Moreover, the entire apparatus can be reduced in size by installing the ionization part and the extraction electrode so as to be integrated.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

  FIG. 1 is a schematic configuration diagram showing a gas cluster ion beam apparatus according to an embodiment of the present invention. Note that members having the same functions as those of the conventional gas cluster ion beam apparatus shown in FIG.

  The gas cluster ion beam apparatus according to the present embodiment includes a vacuum chamber 3 having a nozzle chamber 1 for generating a neutral gas cluster and an ionization chamber 2 for ionizing and accelerating the gas cluster. The nozzle chamber 1 and the ionization chamber 2 are separated by a partition wall 5 installed in the vacuum vessel 3. A skimmer 4 is attached to the center of the partition wall 5.

  The partition wall 5 is connected to the inner wall of the vacuum vessel side plate 15 to which the nozzle 6 is attached by a support member 14. Although only one support member 14 is shown in the figure, a plurality of support members 14 may be installed in the nozzle chamber 1 to connect the partition wall 5 to the inner wall of the vacuum vessel side plate 15. The vacuum vessel side plate 15 has a flange portion 15a attached to the flange portion 3a of the vacuum vessel 3 via an O-ring (not shown) so as to be detachable with bolts (not shown).

  A minute gap of about 0.1 mm is provided between the edge 5a of the partition wall 5 and the inner peripheral surface of the vacuum vessel 3 so as to limit the conductance between the nozzle chamber 1 and the ionization chamber 2. . The width of the edge 5a in the gas flow direction (left-right direction in the figure) is 30 mm. In the present embodiment, the conductance value is set to 10 l / sec or less, and preferably 1 l / sec or less.

  The cage-shaped anode 9 of the ionization section 7 installed in the ionization chamber 2 is supported on the partition wall 5 by a support member 16 made of an insulating material, and the extraction electrode 8 is supported on the anode 9 by a support member 17 made of an insulating material. Has been. In the present embodiment, the anode 9 and the extraction electrode 8 constitute an acceleration electrode.

  The conducting wires 18a and 18b having one end connected to the anode 9 and the filament 10 are connected to an external acceleration power source 12, filament power source 11a, and ionization power source 11b through an insulating pipe 19 connected between the partition wall 5 and the vacuum vessel side plate 15. ing. Further, the extraction electrode 8 installed in the ionization chamber 2 is connected to the partition wall 5 through a conducting wire 18c. The support member 14 is a conductor, and the partition wall 5 is grounded via the support member 14 and the vacuum vessel side plate 15. The anode 9 is supported on the partition wall 5 by a support member 16, and the extraction electrode 8 is supported on the anode 9 by a support member 17. The filament 10 is supported on the partition wall 5 by fixing means (not shown).

  A source gas (for example, Ar gas) supplied from a gas cylinder (not shown) is ejected at supersonic speed by the nozzle 6 in the nozzle chamber 1 to generate a gas cluster by adiabatic expansion. At this time, for example, when the pressure of the source gas of the nozzle 6 is 6 atm, the gas flow rate from the nozzle 6 is about 500 sccm, and the operating pressure of the nozzle chamber 1 is the vacuum pump whose effective exhaust speed is about 300 l / sec. It was about 2 Pa when exhausting (not shown). The generated gas cluster passes through the skimmer 4 and is supplied to the ionization chamber 2 after adjusting the beam shape. The skimmer 4 is formed in a sharp and sharp shape so as not to disturb the gas flow as much as possible.

In the ionization section 7 of the ionization chamber 2, the thermoelectrons emitted from the heated filament 10 by applying a voltage from the filament power supply 11a are accelerated to 100 to 300 V by the anode 9 to which the voltage is applied from the ionization power supply 11b. The gas cluster beam is ionized by collision. The ionized gas cluster beam is accelerated by an electric field formed between the anode 9 and the extraction electrode 8 by applying a high voltage (several tens kV) from the acceleration power source 12 to the anode 9. At this time, the operating pressure of the ionization chamber 2 was about 10 ⁻² Pa when exhausted by a vacuum pump (not shown) having an effective exhaust speed of about 1000 l / sec.

  Then, an accelerated gas cluster beam is irradiated perpendicularly to the surface of the workpiece 13 such as the front substrate and the surface atoms of the workpiece 13 are sputtered in the lateral direction to flatten the surface irregularities. The

  By the way, when the gas cluster ion beam apparatus described above is operated for a long period of time, the ionization section (anode 9 and filament 10) 7 and the extraction electrode 8 in the ionization chamber 2 are deteriorated and contaminated, and the initial performance can be maintained. Therefore, maintenance work such as replacement is required.

  When performing this maintenance work, first, a bolt (not shown) connecting the flange portion 15 a of the vacuum vessel side plate 15 to the flange portion 3 a of the vacuum vessel 3 is removed, and the vacuum vessel side plate 15 is removed from the vacuum vessel 3.

  As described above, the anode 9, the extraction electrode 8, and the filament 10 are installed integrally with the partition wall 5, and the edge 5a of the partition wall 5 and the inner wall surface of the vacuum vessel 3 are configured to be slidable. Then, the removed vacuum vessel side plate 15 is moved to the opposite side of the workpiece 13 with respect to the longitudinal direction of the vacuum vessel 3 (the horizontal direction in the figure), so that the anode 9, the filament 10, and the extraction electrode 8 are integrated with the partition wall 5. Can be removed from the vacuum vessel 3.

  At this time, the conductors 18a and 18b which are power lines of the anode 9 and the filament 10 are also removed from the vacuum vessel 3 by being moved together by the insulating pipe 19 connected between the vacuum vessel side plate 15 and the partition wall 5. Can do.

  Then, after replacing the extraction electrode 8, the anode 9, and the filament 10 removed from the vacuum vessel 3 with new ones, they are assembled into the vacuum vessel 3 in the reverse procedure of the removal operation, and the flange portion 15a of the vacuum vessel side plate 15 is attached. By bolting to the flange portion 3a of the vacuum vessel 3, it is immediately possible to operate.

  Thus, the operation of removing the vacuum vessel side plate 15 from the vacuum vessel 3 allows the anode 9 and filament 10 and the extraction electrode 8 to be removed from the vacuum vessel 3 integrally with the partition wall 5, so that the anode 9, filament 10, The extraction electrode 8 can be easily replaced with good workability, and maintenance work can be easily performed in a short time.

  Further, by replacing the anode 9, filament 10, and extraction electrode 8 outside the vacuum vessel 3 with new ones, the cores of the nozzle 6, skimmer 4, anode 9, filament 10, and extraction electrode 8 after maintenance work are replaced. Stocking can be done easily.

  Furthermore, since the anode 9, the filament 10, and the extraction electrode 8 are not exchanged in the vacuum vessel 3 during maintenance work as in the prior art, the size of the vacuum vessel 3 can be reduced.

1 is a schematic configuration diagram showing a gas cluster ion beam apparatus according to an embodiment of the present invention. The schematic block diagram which shows the gas cluster ion beam apparatus in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nozzle chamber 2 Ionization chamber 3 Vacuum container 4 Skimmer 5 Bulkhead 6 Nozzle 7 Ionization part 8 Extraction electrode 9 Anode 10 Filament 11a Filament power supply 11b Ionization power supply 12 Acceleration power supply 13 Workpiece 14 Support member 15 Vacuum container side plate 15a Flange part 19 Insulation pipe

Claims (3)

A nozzle chamber for generating a neutral gas cluster by ejecting the introduced gas from the nozzle at a high speed and the nozzle chamber are separated by a partition, and the gas cluster is supplied in a beam shape by a skimmer provided in the partition An ionization chamber provided with an ionization chamber, an ionization unit ionizing the gas cluster arranged in the beam shape in the ionization chamber, and the gas cluster arranged in the beam shape ionized in the ionization unit A gas cluster ion beam apparatus having an accelerating electrode system for accelerating the irradiation and irradiating the surface of the workpiece,
The nozzle chamber and the ionization chamber are individually connected to an exhaust system,
The partition wall is slidably installed in the vacuum container, and a vacuum container side plate provided with the nozzle facing the partition wall is detachably fixed to the vacuum container,
The ionization unit and the acceleration electrode system are supported on the partition wall, the partition wall is supported on the vacuum vessel side plate by a support member, and a power supply wiring to the ionization unit includes the vacuum vessel side plate and the partition wall. Connected to the ionization part while maintaining electrical insulation of
A gas cluster ion beam apparatus. The partition wall is installed with a gap with the inner peripheral surface of the vacuum vessel.
The gas cluster ion beam apparatus according to claim 1. The gap has a conductance value of 10 l / sec or less.
The gas cluster ion beam apparatus according to claim 2.

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