Combined beam apparatus

Abstract

The present invention achieves a composite beam device (10), with which it is possible to remove neutral particles generated in a gas ion source (30) and reduce the size of a gas ion beam column (18). The composite beam device (10) includes a focused ion beam device (14), an electron beam device (15), and a low acceleration gas ion beam device (18). The low acceleration gas ion beam device (18) includes a gas ion source (30), an ion beam deflector (31) connected to the gas ion source (30), and an ion beam casing column (32) connected to the ion beam deflector (31) via a bent portion (26). The ion beam deflector (31) and the ion beam casing column (32) are connected to each other via the bent portion (26) so as to be inclined relative to each other.

Description

Technical Field

[0001] The present invention relates to a composite beam apparatus including a focused ion beam apparatus, a scanning electron microscope, and a gas ion beam column. Background Art

[0002] As a method for analyzing the internal structure of a sample such as a semiconductor device or performing three-dimensional observation, a composite beam apparatus equipped with a charged particle beam (Focused Ion Beam; FIB) column and an electron beam (Electron Beam; EB) column is used to perform cross-section forming processing by FIB, and a sample cross-section processing and observation method in which the cross-section is observed by a scanning electron microscope (Scanning Electron Microscope; SEM) is known.

[0003] Patent Document 1 describes a charged particle beam apparatus including a gallium ion beam column, an electron beam column that irradiates an electron beam toward a sample, and a gas ion beam, wherein the gas ion beam has a beam diameter larger than the maximum diameter of the cross-section of the sample.

[0004] According to the technology described in Patent Document 1, finish processing of a sample cross-section and acquisition of a high-precision SEM image of the sample cross-section can be efficiently performed in a short time.

[0005] Patent Document 2 describes a technology in which the axis for extracting an ion beam and the axis for irradiating the sample with the ion beam are inclined, so that neutron impurities or gaseous neutral molecules do not reach the sample. Prior Art Documents Patent Documents

[0006] Patent Document 1 Japanese Unexamined Patent Publication No. 2019-145328 Patent Document 2 Japanese Patent No. 5127148 Summary of the Invention [Problems that the invention aims to solve]

[0007] However, in the technology described in Patent Document 1, neutral particles generated simultaneously with ions in the plasma ion source (gas ion source) used to generate gas ions are mixed into the ion beam and irradiated onto the sample. Since the neutral particles generate secondary electrons, they interfere with intermediate observation by SEM.

[0008] Furthermore, in a device that mounts an SEM column, a FIB column, and a gas ion column in the same apparatus and irradiates charged particles at the same location, as in the technology described in Patent Document 2, there is insufficient space to mount the columns.

[0009] Therefore, in the technology described in Patent Document 2, simply having a bent section to tilt the axis from which the ion beam is extracted and the axis from which the ion beam is irradiated onto the sample made it difficult to miniaturize the bent section and the gas ion column (gas ion beam tube).

[0010] The objective of the present invention is to realize a combined beam system that can remove neutral particles generated in a gas ion source and also enables miniaturization of the gas ion beam tube. [Means for solving the problem]

[0011] To achieve the above objective, the present invention is configured as follows.

[0012] The combined beam system is In a combined beam apparatus having a focused ion beam apparatus, an electron beam apparatus, and a low-acceleration gas ion beam apparatus, the low-acceleration gas ion beam apparatus comprises a gas ion source, an ion beam deflection unit connected to the gas ion source, and an ion beam casing connected to the ion beam deflection unit via a bent portion, wherein the ion beam deflection unit and the ion beam casing are The aforementioned They are connected to each other at an angle via a bent portion. A Blanca deflector for deflecting the ion beam is positioned at the aforementioned bent section. , The system further comprises a boosting power supply that supplies voltage to the aforementioned Blanka deflector. . Effects of the Invention

[0013] According to the present invention, a composite beam apparatus capable of removing neutral particles generated in a gas ion source and achieving size reduction of a gas ion beam column can be realized. Brief Description of the Drawings

[0014] [Figure 1] FIG. 1 is a schematic configuration diagram showing an entire composite beam apparatus to which an embodiment of the present invention is applied. [Figure 2] FIG. 2 is a schematic configuration diagram of one embodiment and is an explanatory view of a part of the composite beam apparatus shown in FIG. 1. [Figure 3] FIG. 3 is an internal configuration diagram of a gas ion beam column 18. Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Examples

[0016] FIG. 1 is a schematic configuration diagram showing an entire composite beam apparatus 10 to which an embodiment of the present invention is applied.

[0017] The composite beam apparatus 10 according to the embodiment of the present invention includes: a sample chamber 11 capable of maintaining a vacuum state inside; and a stage 12 capable of fixing a sample stage 13 for placing a sample S inside the sample chamber 11.

[0018] The composite beam apparatus 10 includes, within a predetermined irradiation region (that is, a scanning range ) inside the sample chamber 11, a gallium ion An on-beam column 14 (focused ion beam device) is provided. Such a gallium ion beam column 14 is provided with a gallium source using liquid gallium or the like (not shown in FIG. 1). A gallium ion beam (FIB) having a beam diameter of, for example, 1 μm or less is irradiat ed from a front end 14a of the gallium ion beam column, which is the emission end of the gallium ion beam column 14.

[0019] The acceleration voltage of the gallium ion beam column 14 (focused ion beam device) is 50 V to 5000 V.

[0020] The composite beam device 10 is provided with an electron beam column 15 (electron beam device) that irradiates an electron beam EB toward an irradiation target within a predetermined irradiation region inside a sample chamber 11, for example, a sample S.

[0021] Further, the composite beam device 10 includes a secon dary electron detector 16 that detects secondary electrons generated from the sample S by irradiation of the electron beam EB. The secondary electron detector 16 detects the intensity (that is, the amount of secondary electrons) of secondary charged particles (secondary electrons) emitted from an irradiation target such as the sample S when the irradiation target is irradiated with the electron beam, and outputs information on the detected amount of secondary electrons.

[0022] The secondary electron detector 16 is disposed inside the sample chamber 11 at a position where the amount of secondary electrons can be detected, for example, at a position obliquely above an irradiation target such as the sample S within the irradiation region.

[0023] The composite beam device 10 is provided with a gas ion beam column 18 (low-acceleration gas ion beam device) that irradiates a gas ion beam toward an irradiation target within a predetermined irradiation region inside the sample chamber 11, for example, the sample S. In the present embodiment, an argon ion beam using argon, which is a noble gas, is used as the gas ion beam.

[0024] The charged particle beam device 10 includes a gas gun that supplies gas to an irradiation target, for example, the surface of the sample S It is equipped with 17. The gas gun 17 is equipped with, for example, a nozzle with an outer diameter of about 200 μm.

[0025] The gas gun 17 supplies, for example, an etching gas to selectively accelerate the etching of a sample by a gallium ion beam, and a deposition gas to form a deposition film of metal or an insulator on the surface of the sample S.

[0026] The combined beam apparatus 10 comprises a control unit 21, a display device 22, and an input device 23. The control unit 21 is a control means that controls the gallium ion beam tube 14, electron beam tube 15, secondary electron detector 16, gas ion beam tube 18, gas gun 17, and other components that make up the combined beam apparatus 10. The gallium ion beam tube 14 irradiates the sample S with a gallium ion beam from its front end 14a.

[0027] Furthermore, the electron beam tube 15 irradiates the sample S with an electron beam EB from its front end 15a.

[0028] Furthermore, the gas ion beam tube 18 irradiates the sample S with an argon ion beam GB from its front end 18a.

[0029] The beam axes of the gallium ion beam, electron beam EB, and argon ion beam GB intersect at point P.

[0030] The control unit 21 consists of, for example, a personal computer and an interface. The display device 22 displays an image of the sample S based on secondary electrons detected by the secondary electron detector 16. Commands, data, and other inputs are input to the control unit 21 via the input device 23.

[0031] In addition to the configuration described above, the combined beam apparatus 10 is also equipped with a needle mechanism (not shown) for moving the sample S placed on the stage 12.

[0032] Figure 2 is a schematic diagram of one embodiment and is an explanatory diagram of a part of the composite beam apparatus 10 shown in Figure 1.

[0033] In Figure 2, the gas ion beam microscope tube 18 comprises a gas ion source 30, an ion beam deflection unit 31, and an ion beam casing 32. A bent section 26 is formed between the ion beam deflection unit 31 and the ion beam casing 32. The centerlines of the ion beam deflection unit 31 and the ion beam casing 32 are not in a straight line, but have an angle between them. In other words, the centerlines of the ion beam deflection unit 31 and the ion beam casing 32 intersect at the bent section 26.

[0034] The angle between the centerline of the ion beam deflection unit 31 and the centerline of the ion beam casing 32 is the angle for separating the ion beam 28 and the neutral particles 29, and is an angle that allows the neutral particles 29 to be separated from the ion beam and the neutral particles 27. The line segment formed by the neutral particles 29 is a line segment that extends in the same direction as the line segment formed by the ion beam and the neutral particles 27.

[0035] On the other hand, the line segment formed by the ion beam 28 extends in a different direction from the line segment formed by the ion beam and neutral particles 27. The ion beam deflection unit 31 and the ion beam casing 32 are connected to each other at an inclination via the bent portion 26.

[0036] The ion beam and neutral particles 27 generated in the gas ion source 30 are separated into an ion beam 28 and neutrons 29 at the bent section 26.

[0037] In other words, the ion beam 28 is focused by the condenser lens 2 (described later), then bent by the Blanca deflector 3 installed in the bending section 26, and then focused via the downstream objective lens 7 by the scanning deflector 8 (described later) and scanned over the sample S. A voltage is applied to the Blanca deflector 3, as described later. If no voltage is applied to the Blanca deflector 3 in the bending section 26, the ion beam cannot pass through the bending section 26, so the Blanca deflector 3 also functions as a Blanca to stop the ion beam.

[0038] In this embodiment, the gas ion beam tube (low-accelerated gas ion beam device) 18 is set to a lower energy than the gallium ion beam tube (focused ion beam device) 14.

[0039] Figure 3 is an internal diagram of the gas ion beam tube 18.

[0040] In Figure 3, the gas ion beam microscope tube 18 in one embodiment employs a boosting optical system that accelerates ions between two lenses in order to improve processing performance at low acceleration (less than 1 keV). In the boosting optical system, ions are accelerated between the condenser lens 2 and the objective lens 7 when the acceleration voltage is low.

[0041] This allows the ion beam 28 to decelerate, converge, and spread, preventing ions from being lost before reaching the objective lens 7, and enabling the irradiation of the sample S with an ion current of several tens of nA.

[0042] The ion beam emitted from the ion source 1 is focused by the condenser lens 2, deflected by the blanker deflector 3 located in the bending section 26, and separated from the neutral particles 29 by the blanking aperture 4 located in the accelerating tube 5.

[0043] After the ion beam 28 passes through the blanking aperture 4, the beam current is adjusted to an appropriate value by the beam limiting aperture 6. To adjust the current value with the beam limiting aperture 6, the voltage of the condenser lens 2 is changed, and the beam's focusing position is appropriately altered. The ion beam 28 passes through the objective lens 7, is focused on the sample S, scanned by the scanning deflector 8, deflected to an arbitrary position, and then irradiated.

[0044] The Blanca deflector 3 and blanking aperture 4 are installed inside the accelerating tube 5 that accelerates the ions. In order to deflect the ion beam 28 to the bending angle of the gas ion beam tube 18, a voltage proportional to the energy of the ions must be applied.

[0045] The voltage, which is proportional to the energy of the ions, will depend on both the voltage of the accelerating tube 5 (voltage from the boosting power supply 24) and the ion acceleration voltage.

[0046] In this embodiment, voltage is supplied to the blanker deflector 3 from a low-voltage blanking power supply 25 that is suspended by the boosting power supply 24. The blanking power supply 25 supplies voltage to the blanker deflector 3 together with the boosting power supply 24.

[0047] This eliminates the need for a high-voltage power supply. Furthermore, the blanking voltage can be stabilized in a short time.

[0048] In this embodiment, since a blanker deflector 3 with a blanker function is used in the electrostatic deflector of the bent section 26, only the space of one deflector is required, and the gas ion beam tube 18 can be miniaturized.

[0049] Furthermore, since electrodes and power supplies that were required when a dedicated blanker was used are no longer needed, manufacturing costs can be reduced.

[0050] The Blanca deflector 3 uses parallel plates, parallel plates (shaped like concentric cylinders cut out), and multi-pole electrodes to improve symmetry. This suppresses distortion of the beam shape after deflection, allowing a symmetrical, round beam shape to be obtained on the sample.

[0051] At low acceleration (below 1 keV), the beam spreads out during flight due to the Coulomb force between charged particles. It is inexpensive. A boost voltage is applied by the boosting power supply 24 to increase the current passing through the blanking aperture 4.

[0052] As described above, the present invention is configured to remove neutral particles generated in the gas ion source and to realize a combined beam apparatus that enables miniaturization of the gas ion beam tube. [Explanation of Symbols]

[0053] 1...Ion source (gas ion source), 2...Condenser lens, 3...Blanca deflector, 4...Blanking aperture, 5...Accelerating tube, 6...Beam limiting aperture, 7...Objective lens, 8...Scanning deflector, 10...Combined beam apparatus, 11...Sample chamber, 1 2... Stage (sample stage), 13... Sample stage, 14... Gallium ion battery Ion beam tube (focused ion beam device), 14a...Gallium ion beam tube front end, 15...Electron beam tube (electron beam device), 15a...Electron beam tube front end, 16...Secondary electron detector, 17...Gas gun, 18...Gas ion beam tube (low-acceleration gas ion beam device), 18a...Gas ion beam tube front end, 21...Control unit, 22...Display device, 23...Input device, 24...Boosting power supply, 25...Blanking power supply, 26...Bend section, 27...Ion beam + neutron beam, 28...Ion beam, 29...Neutron beam, 30...Gas ion source, 31...Ion beam deflection section, 32...Ion beam housing, EB...Electron beam, GB...Argon ion beam, P...Intersection, S...Sample

Claims

1. In a combined beam apparatus having a focused ion beam apparatus, an electron beam apparatus, and a low-acceleration gas ion beam apparatus, The low-acceleration gas ion beam apparatus is, The system comprises a gas ion source, an ion beam deflection unit connected to the gas ion source, and an ion beam housing connected to the ion beam deflection unit via a bent portion. The ion beam deflection section and the ion beam casing are connected to each other at an inclination via the bent section, A Blanca deflector for deflecting the ion beam is positioned at the aforementioned bent section. A composite beam apparatus further comprising a boosting power supply that supplies voltage to the aforementioned Blanca deflector.

2. In the combined beam apparatus according to claim 1, A composite beam apparatus further comprising a blanking power supply that supplies voltage to the blanker deflector together with the boosting power supply.

3. In the combined beam apparatus according to claim 1, The low-accelerating gas ion beam apparatus is a combined beam apparatus characterized by having lower energy than the focused ion beam apparatus.

4. In the combined beam apparatus according to claim 3, A combined beam apparatus characterized in that the acceleration voltage of the focused ion beam apparatus is 50V to 5000V.

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