WO2022244149A1 - イオンミリング装置 - Google Patents
イオンミリング装置 Download PDFInfo
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- WO2022244149A1 WO2022244149A1 PCT/JP2021/019012 JP2021019012W WO2022244149A1 WO 2022244149 A1 WO2022244149 A1 WO 2022244149A1 JP 2021019012 W JP2021019012 W JP 2021019012W WO 2022244149 A1 WO2022244149 A1 WO 2022244149A1
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- 238000000992 sputter etching Methods 0.000 title claims abstract description 47
- 238000010884 ion-beam technique Methods 0.000 claims abstract description 148
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Images
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
- H01J37/305—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating or etching
- H01J37/3053—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating or etching for evaporating or etching
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J27/00—Ion beam tubes
- H01J27/02—Ion sources; Ion guns
- H01J27/16—Ion sources; Ion guns using high-frequency excitation, e.g. microwave excitation
- H01J27/18—Ion sources; Ion guns using high-frequency excitation, e.g. microwave excitation with an applied axial magnetic field
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement, ion-optical arrangement
- H01J37/08—Ion sources; Ion guns
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/24—Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for
- H01J37/243—Beam current control or regulation circuits
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/26—Electron or ion microscopes; Electron or ion diffraction tubes
- H01J37/261—Details
- H01J37/265—Controlling the tube; circuit arrangements adapted to a particular application not otherwise provided, e.g. bright-field-dark-field illumination
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/30—Electron-beam or ion-beam tubes for localised treatment of objects
- H01J37/305—Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating or etching
Definitions
- the present invention relates to an ion milling device suitable for pretreatment processing of samples observed with an electron microscope.
- the ion milling method is a processing method in which accelerated ions collide with the sample, and the sample is milled using the sputtering phenomenon in which the ions repel atoms and molecules.
- This method is used for metals, glasses, ceramics, electronic parts, composite materials, etc.
- electronic parts it is used for internal structure, cross-sectional area shape, film thickness evaluation, crystal state, failure and foreign matter cross-section analysis.
- it is widely used as a cross-sectional sample preparation method for obtaining morphological images, sample composition images, channeling images by scanning electron microscope, X-ray analysis, crystal orientation analysis, etc.
- the scope of application has been expanded to structure observation for the purpose of process control in mass production processes in the field of semiconductors and the like.
- a small Penning discharge ion gun with a simple configuration is used as the ion gun.
- the Penning discharge type ion gun electrons emitted from the cathode are ionized by rotating due to the magnetic field of the permanent magnet and colliding with the process gas introduced into the ion gun.
- the electrons that are orbiting due to the magnetic field reciprocate between the cathodes, thereby lengthening the electron trajectory and improving the ionization efficiency. .
- This has the advantage that a high plasma density can be obtained.
- a high plasma density is essential for this purpose, and it is important to supply an appropriate magnetic field strength on the ion gun axis. Fluctuations in the magnetic field intensity cause a decrease in plasma density, affect the ion beam performance, and change the processing shape of the sample processing surface.
- the ion milling device processes the sample by irradiating the sample surface with an unfocused ion beam emitted from a Penning discharge type ion gun.
- the ion density distribution of the non-focused ion beam has the characteristic that it is highest at the irradiation center and decreases toward the outside. Since the ion density is closely related to the processing speed of the sample, the ion density distribution is directly reflected in the processing shape of the sample processing surface. Therefore, when the ion milling apparatus is used for pretreatment processing of a sample to be observed with an electron microscope, the difference in ion density distribution is directly linked to the difference in the observation surface observed with the electron microscope.
- Patent Document 1 discloses the basic structure of a Penning discharge ion gun.
- Patent Literature 2 discloses a Penning discharge type ion gun that achieves a higher processing speed than conventional ion guns by limiting the magnetic field intensity of the built-in magnet to an appropriate value.
- An ion milling apparatus which is an embodiment of the present invention, comprises a vacuum chamber whose internal air pressure is controlled by a vacuum exhaust system, an ion gun attached to the vacuum chamber for irradiating an unfocused ion beam, and It has a sample stage for holding a sample, an ion beam characteristic measurement mechanism for measuring ion beam characteristics for estimating the processing profile of the sample by the ion beam, and a controller, and applies a magnetic field to the ionization chamber of the ion gun.
- the magnetic field generator to be generated is an electromagnet having an electromagnetic coil and a magnetic path, and the controller controls the current value applied to the electromagnetic coil based on the ion beam characteristics measured by the ion beam characteristics measuring mechanism.
- FIG. 1 is a schematic diagram (cross-sectional view) of an ion beam and a sample processed by the ion beam;
- FIG. 2 is a schematic diagram (top view) of a sample processed by an ion beam; It is a figure which shows the relationship between the axial magnetic flux density of an ion gun, and a milling processing speed.
- FIG. 5 is a diagram schematically showing how the machining depth and machining shape fluctuate under the influence of on-axis magnetic flux density;
- FIG. 5 is a diagram showing an example profile of on-axis magnetic flux density;
- 5 is a diagram showing an example profile of on-axis magnetic flux density; It is an ion beam profile measured by an ion beam characteristic measuring mechanism. 4 is a flowchart for adjusting ion beam irradiation conditions; It is another configuration example of the ion milling device. It is another configuration example of the ion milling device.
- FIG. 1 is a schematic diagram showing the main part of the ion milling device 300 of this embodiment.
- a Penning discharge type ion gun 1 comprises elements necessary for generating ions therein, and irradiates a sample 6 with an ion beam 2 . Its internal structure will be described later.
- a gas source 41 is connected to the ion gun 1 through a gas supply mechanism 40 , and a gas flow rate controlled by the gas supply mechanism 40 is supplied into the plasma generation chamber of the ion gun 1 .
- the gas supply mechanism 40 includes all components for adjusting the flow rate of the gas to be ionized and supplying it inside the ion gun.
- Ar gas is used as an introduced gas, for example.
- Irradiation conditions of the ion beam 2 are controlled by the ion gun controller 3 .
- the ion gun control unit 3 includes all components for adjusting the voltage conditions applied to the components of the ion gun 1 and emitting the ion beam 2 .
- the vacuum chamber 4 is controlled to atmospheric pressure or vacuum by an evacuation system 5 .
- a sample 6 is held on a sample stage 7 , and the sample stage 7 is held by a sample stage 8 .
- a sample stage drive unit 9 is provided to drive the sample stage 8 .
- the sample 6 is irradiated with the ion beam 2 emitted from the ion gun 1 without being focused. Therefore, the ion beam distribution near the ion beam irradiation point of the sample 6 has the highest ion density in the central portion. , the ion density decreases from the center toward the outside. Since the ion density is directly linked to the processing speed of the sample, the processed shape of the sample greatly depends on the ion beam distribution near the ion beam irradiation point.
- the ion milling apparatus 300 has means for measuring the intensity distribution of the unfocused ion beam from the ion gun 1 (ion beam characteristic measuring mechanism) for the purpose of improving processing speed controllability and processing profile reproducibility.
- a current probe 52 is arranged between the ion gun 1 and the sample 6, and the ion beam current value of the ion beam 2 is measured by the ammeter 50.
- FIG. The ammeter 50 includes all components for outputting ion information captured by a current probe 52 irradiated with the ion beam 2 as a current value.
- the current probe 52 is a linear conductive member extending in the Y direction, and is reciprocally driven in the X direction perpendicular to the Y direction in the figure by the current probe driving unit 51 .
- the trajectory of the current probe 52 can be determined. It is possible to obtain an intensity distribution of the ion beam current (hereinafter referred to as an ion beam profile) along the .
- the ion milling device 300 is controlled by the device control section 200 .
- a display unit 210 and an input unit 220 for inputting a user's instruction are connected to the device control unit 200 .
- the device control unit 200 is connected to control mechanisms of various parts of the ion milling device such as the ion gun control unit 3, the vacuum exhaust system 5, the gas supply mechanism 40, the coil control unit 62, and the sample stage drive unit 9. ing. It is also connected to a monitor mechanism such as an ammeter 50 that monitors the operational status of the ion milling apparatus.
- the display unit 210 displays the ion beam profile obtained from the output of the ammeter 50, as well as the control parameters and operating state of the device. Before milling the actual device, the user checks the ion beam profile of the ion beam 2 and adjusts the control parameters of the ion gun 1 through the input unit 220 so as to obtain the desired ion beam characteristics. can do. Further, an operation program for adjusting the control parameters may be executed based on the monitoring result of the monitoring mechanism of the ion milling apparatus 300 including the ion beam characteristic measuring mechanism.
- the main control parameters for adjusting the ion beam characteristics are the discharge voltage and the gas flow rate, and the inventors' examination revealed that adjustment by these control parameters alone is insufficient. .
- a parameter that greatly affects the ion beam intensity is the on-axis magnetic flux density.
- a conventional Penning discharge ion gun uses a permanent magnet to generate a magnetic field. Due to the nature of permanent magnets, the magnetic field strength cannot be controlled and individual differences are large. It is difficult to cancel variations in axial magnetic flux density due to individual differences in permanent magnets by adjusting the discharge voltage and gas flow rate. For this reason, the conventional ion milling apparatus has a large machine difference, and has inevitably been insufficient in machining speed controllability and machining profile reproducibility.
- the on-axis magnetic field density of the ion gun 1 can be controlled in order to satisfy the advanced processing speed controllability and processing profile reproducibility required for mass production management. Therefore, the magnetic field generator of the ion gun 1 is of an electromagnet type having an electromagnetic coil 61, a magnetic path 60, and a coil control section 62, and the on-axis magnetic flux density of the ion gun 1 can be adjusted by the coil current.
- the coil controller 62 contains all the components for adjusting the current applied to the electromagnetic coil 61 to provide the ion gun 1 with the proper axial magnetic flux density.
- the current value of the electromagnetic coil 61 is newly added as a control parameter for adjusting the ion beam characteristics, making it possible to control the on-axis magnetic flux density. can be significantly increased.
- FIG. 2 is a cross-sectional view showing the configuration of the ion gun 1 and related peripheral parts.
- the first cathode 11 is made of a conductive magnetic material such as pure iron and has a disc shape, and is provided with a hole for introducing gas into the ionization chamber 18 .
- the second cathode 12 is made of a conductive magnetic material such as pure iron and formed in a disc shape, and has a cathode exit hole in the center.
- the first cathode 11 and the second cathode 12 are each connected to a cathode ring 14 and arranged to face each other.
- a cylindrical insulator 16 is arranged inside the cathode ring 14 .
- the anode 13 is fitted inside the insulator 16 , the outer surface of the anode 13 is in contact with the inner surface of the insulator 16 and the inner surface faces the ionization chamber 18 .
- the anode 13 is made of a conductive non-magnetic material such as aluminum.
- Anode 13 is electrically insulated from first cathode 11 and second cathode 12 and cathode ring 14 by insulator 16 .
- the accelerating electrode 15 is made of a conductive non-magnetic material such as stainless steel, and has an accelerating electrode exit hole in the center.
- the magnetic field generating device of the ion gun 1 is an electromagnet system that includes an electromagnetic coil 61, a magnetic path 60, and a coil control section 62.
- the electromagnetic coil 61 is provided outside the vacuum chamber 4 and on the outer peripheral portion of the ion gun base 17 . An opening is provided to surround the ring 14 . It should be noted that the electromagnetic coil 61 generates heat by applying a current to the electromagnetic coil 61 . By arranging the electromagnetic coil 61 outside the vacuum chamber 4, heat dissipation from the electromagnetic coil 61 can be facilitated.
- the gas supply mechanism 40 is connected to the ion gun base 17 and includes all components for adjusting the flow rate of the gas to be ionized and supplying it inside the ion gun.
- Ar gas will be described as an example.
- a hole is provided in the ion gun base 17 and the cathode 11 , and Ar gas introduced from the gas supply mechanism 40 is introduced into the ionization chamber 18 .
- the Ar gas introduced into the ionization chamber 18 is maintained at an appropriate gas partial pressure, and a discharge voltage of about 0 to 4 kV is applied between the first cathode 11, the second cathode 12 and the anode 13 by the discharge power supply 21. is applied, electrons are generated due to the potential difference between the anode and the cathode.
- the generated electrons are bent by the magnetic field formed by the electromagnetic coil 61 and the magnetic path 60 and undergo a revolving motion.
- an accelerating voltage of about 0 to 10 kV is applied between the cathode 12 and the accelerating electrode 15 by the accelerating power source 22 to accelerate the Ar ions and eject the ion beam 2 out of the ion gun 1 .
- some of the positive ions generated in the ionization chamber 18 pass through the cathode exit hole of the second cathode 12, are accelerated by the accelerating electrode 15, and are emitted from the accelerating electrode exit hole to the outside of the ion gun 1.
- a sample 6 is processed by an ion beam 2 composed of ions.
- FIGS. 3A and 3B show schematic diagrams of the ion beam 2 emitted from the ion gun 1 and the sample 6 processed by it.
- 3A is a sectional view of the ion gun 1, the ion beam 2, and the sample 6, and FIG. 3B is a top view of the sample 6.
- FIG. 3A the ion beam 2 emitted from the ion gun 1 irradiates the sample 6 without being focused, so that it is formed in a Gaussian distribution around the beam center 105 . For this reason, the ion beam distribution at the ion beam irradiation point of the sample 6 has the characteristic that the ion density is highest in the central portion and decreases toward the outside from the center.
- the ion density is directly linked to the processing speed of the sample, and the milling processing area 100 on the surface of the sample 6 has the largest processing amount at the center of the ion beam irradiation, and has a shape in which the processing amount decreases from the center toward the outside.
- the milling region 100 may vary depending on the processing depth and inclination angle of the milling region 100.
- the shape of the exposed measurement pattern 101 changes. In order to obtain accurate evaluation results, high precision is required for the reproducibility of the machined shape.
- FIG. 4 is a diagram showing the relationship between the milling speed and the on-axis magnetic flux density of the ion gun.
- an ion gun using a permanent magnet as a magnetic field generator was used, and the applied milling conditions were an acceleration voltage condition of 6 kV, a discharge voltage of 1.5 kV, an Ar gas as the gas introduced into the ion gun, and a flow rate of It was 0.07 cm 3 /min.
- the material to be processed was silicon, and as shown in FIG. 3A, the surface of the sample 6 was irradiated with the ion beam 2 perpendicularly, and the milling time was set to 1 hour. As can be seen from FIG.
- the milling speed is 360 ⁇ m/hr, increases to 385 ⁇ m/hr at 145 mT, and decreases to 340 ⁇ m/hr at 160 mT.
- the on-axis magnetic flux density of the ion gun 1 is a factor that greatly affects the milling speed, that is, the ion beam intensity.
- the magnetic field generating device is a permanent magnet, such individual differences result in machine differences, resulting in lower reproducibility.
- the performance of the permanent magnet is deteriorated due to heating.
- the magnetic field generator of the ion gun 1 is a permanent magnet
- the axial magnetic flux density varies greatly due to individual differences and deterioration over time. Fluctuations in ion beam properties due to magnetic flux density may not be corrected by other control parameters.
- FIG. 5 schematically shows how the machining depth and machining shape change due to the influence of the on-axis magnetic flux density in the Penning discharge type ion gun 1 .
- the on-axis magnetic flux density affects the orbital motion of electrons generated in the ionization chamber 18 .
- the diameter of the electron rotation is changed by the on-axis magnetic flux density, the spread of the plasma region and the plasma density are affected, and the ion beam characteristics are varied.
- This influence affects the spread of the ion beam 115 as shown in FIG. 5, and the processing profile 125 also fluctuates.
- the machining profile 125 of the milling process area 100 cannot be formed with high reproducibility, the shape of the measurement pattern 101 that appears changes, and this cannot be applied to mass production process control. .
- FIG. 6A is the profile of the axial magnetic flux density when the current value applied to the electromagnetic coil 61 is 2.6 A, and the maximum magnetic field is 350 mT.
- FIG. 6B shows the profile of the axial magnetic flux density when the current value applied to the electromagnetic coil 61 is 3.7 A, and the maximum magnetic field is 500 mT.
- the range indicated by the arrows in both magnetic field profiles corresponds to the ionization chamber 18 .
- the magnetic field profile in the ionization chamber 18 has a similar shape, and it can be seen that an increase in the current value lifts the magnetic field profile in the direction of high density without changing the shape of the magnetic field profile. From this, it can be seen that ion beam profile control by adjusting the on-axis magnetic flux density is effective.
- the ion milling apparatus 300 has an ion beam characteristic measuring mechanism in order to control the ion beam characteristic by adjusting the axial magnetic flux density of the ion gun.
- FIG. 7 shows an ion beam profile measured by the current probe 52. As shown in FIG. The horizontal axis indicates the beam measurement position, and the vertical axis indicates the ion beam current measured by the current probe 52 .
- the ion beam profile to be measured is the sum of the ion beam profile flowing due to Ar ions colliding with the current probe 52 and the background noise profile due to electrons generated due to the irradiation of the ion beam. Therefore, it is necessary to remove the effect of the background noise profile from the measured ion beam profile.
- the background noise profile fluctuates depending on the measurement position due to variations in the generation of secondary electrons and backscattered electrons and differences in the amount of electron collision with the current probe 52 depending on the beam measurement position. Secondary electrons and backscattered electrons generated by Ar ion collisions have negative charges. A voltage is applied to electron trap 55 .
- An electron trap driver 54 is provided to move the electron trap 55 so that the electron trap 55 does not block the ion beam 2 during processing of the sample 6 . Also, in order to prevent the electron trap 55 from becoming a source of noise due to collision of ions, it is desirable to use a light element and low sputtering yield material for the electron trap 55 . Specifically, it is desirable to use graphite carbon.
- the device control unit 200 evacuates the vacuum chamber 4 by the vacuum exhaust system 5 .
- a target ion beam profile (referred to as a guideline profile) is read and displayed on the display unit 210 .
- the device control unit 200 controls the coil control unit 62, applies the coil current conditions held as initial settings to the electromagnetic coil 61 of the electromagnet ion gun 1, and creates a desired axial magnetic flux density in the ion gun 1. Generate a magnetic field.
- the device control unit 200 supplies the ion gun 1 with Ar gas whose flow rate is controlled by the gas supply mechanism 40 .
- the device control unit 200 sets the ion beam irradiation conditions held as processing conditions by the ion gun control unit 3 , and emits the ion beam 2 from the ion gun 1 .
- the ion beam irradiation conditions determined as processing conditions are the acceleration voltage and discharge voltage of the ion gun 1 .
- the device control unit 200 controls the current probe driving unit 51 to reciprocate the current probe 52 in the X direction while measuring the ion beam current value with the ammeter 50. .
- the device control unit 200 acquires an ion beam profile by associating the position of the current probe 52 in the X direction with the ion beam current value measured by the ammeter 50 at that position.
- the device control unit 200 displays the acquired ion beam profile together with the pointer profile on the display unit 210 .
- the device control unit 200 compares the ion beam profile acquired in step 506 with the guideline profile read in step 501, and starts the machining process if the desired ion beam profile has been acquired; , the steps from adjustment of the applied current to the electromagnetic coil (step 502) are repeated, and the ion beam profile is acquired again under the adjusted on-axis magnetic flux density conditions. If the difference between the acquired ion beam profile and the guideline profile is small, the ion gun controller 3 may control the discharge voltage and the gas supply mechanism 40 may control the flow rate of the Ar gas.
- FIG. 9 is a schematic diagram showing the main part of an ion milling apparatus 301 having an ion beam characteristic measuring mechanism different from the example of FIG.
- the same components as those in FIG. 1 are denoted by the same reference numerals, and overlapping descriptions are omitted.
- the ion beam characteristics measuring mechanism of the ion milling apparatus 301 includes a phosphor 82 formed on a thin film, a phosphor driver 81 for driving the phosphor so that the phosphor 82 is irradiated with an ion beam, and an ion beam
- a camera 83 is provided at a position where the ion beam 2 is not irradiated and photographs the phosphor 82, and the intensity distribution of the ion beam 2 is measured from the photographed data. This utilizes the fact that the emission intensity of the phosphor 82 depends on the intensity of the ion beam.
- a two-dimensional intensity distribution of the ion beam 2 along the fluorescent screen may be treated as the ion beam profile, or an arbitrary one-dimensional intensity distribution of the ion beam 2 may be treated as the ion beam profile.
- FIG. 10 is a schematic diagram showing the main part of an ion milling apparatus 302 having an ion beam characteristic measuring mechanism different from the example of FIG.
- the same components as those in FIG. 1 are denoted by the same reference numerals, and overlapping descriptions are omitted.
- the ion beam characteristic measurement mechanism uses an ion beam profile indicating the intensity distribution of the ion beam current of the ion beam as the ion beam characteristic for estimating the processing profile of the sample 6 by the ion beam 2. is used.
- the ion beam characteristic measuring mechanism estimates the amount of milling of the sample 6 by the ion beam 2 per unit time and uses it as the ion beam characteristic.
- the ion beam characteristic measuring mechanism of the ion milling apparatus 302 includes a probe 72 arranged near the sample table 7 on which the sample 6 is placed.
- the probe 72 is a crystal oscillator, and oscillates at a constant frequency when a voltage is applied.
- the mass of the probe 72 changes when the workpiece that has been repelled from the sample 6 by the collision of the ions emitted from the ion gun 1 reattaches to the probe 72 .
- the oscillation frequency of the crystal oscillator changes, so that the film thickness meter 71 calculates the change in the adhesion amount of the workpiece from the change in the oscillation frequency, thereby calculating the amount of milling of the sample per unit time by the ion beam. can be estimated.
- the processing profile of the sample 6 is the same, the amount of the workpiece generated by processing the sample 6 and adhering to the probe 72 is also the same. Therefore, in the ion milling device 302, the beam intensity of the ion beam 2 during processing can be estimated.
- the on-axis magnetic flux density of the ion gun 1 may be controlled so that the oscillation frequency of the ion gun 1 is kept within a predetermined range.
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Abstract
Description
Claims (10)
- 真空排気系により内部の気圧が制御される真空チャンバーと、
前記真空チャンバーに取り付けられ、非集束のイオンビームを照射するイオンガンと、
前記真空チャンバー内に配置され、試料を保持する試料台と、
前記イオンビームによる前記試料の加工プロファイルを推定するためのイオンビーム特性を計測するイオンビーム特性計測機構と、
制御部とを有し、
前記イオンガンのイオン化室に磁場を発生させる磁場発生装置は、電磁コイルと磁路とを備える電磁石であり、
前記制御部は、前記電磁コイルに印加する電流値を、前記イオンビーム特性計測機構の計測したイオンビーム特性に基づき制御するイオンミリング装置。 - 請求項1において、
前記イオンビーム特性計測機構は、前記イオンビーム特性として前記イオンビームのイオンビーム電流の強度分布を示すイオンビームプロファイルを計測するイオンミリング装置。 - 請求項2において、
前記イオンビーム特性計測機構は、第1の方向に延在する線状のイオンビーム電流測定子と、前記イオンビームを横切るように、前記第1の方向と直交する第2の方向に延びる軌道に沿って、前記イオンビーム電流測定子を移動させる電流測定子駆動部とを備え、
前記制御部は、前記イオンビーム電流測定子に流れるイオンビーム電流と前記イオンビーム電流測定子の前記軌道上の位置とを対応付けることにより、前記イオンビームプロファイルを計測するイオンミリング装置。 - 請求項3において、
前記イオンビーム特性計測機構は、前記軌道の近傍に配置される電子トラップを備え、
前記制御部は、前記イオンビーム特性計測機構による前記イオンビームプロファイルの計測期間中、前記電子トラップに所定の正電圧を印加するイオンミリング装置。 - 請求項2において、
前記イオンビーム特性計測機構は、薄膜体上に形成された蛍光体と、前記蛍光体に前記イオンビームが照射されるように前記蛍光体を駆動させる蛍光体駆動部と、前記蛍光体を撮影するカメラとを備え、
前記制御部は、前記カメラの撮影データから前記イオンビームプロファイルを計測するイオンミリング装置。 - 請求項2において、
前記制御部は、前記イオンビームが目標とする指針プロファイルを読み込み、前記イオンビーム特性計測機構が計測したイオンビームプロファイルを、前記指針プロファイルにあわせるよう前記電磁コイルに印加する電流値を調整するイオンミリング装置。 - 請求項1において、
前記イオンビーム特性計測機構は、前記イオンビーム特性として前記イオンビームによる前記試料の単位時間あたりのミリング量を推定するイオンミリング装置。 - 請求項7において、
前記イオンビーム特性計測機構は、前記試料台の近傍に保持される水晶振動子を備え、
前記制御部は、前記試料に前記イオンビームが照射されることにより前記試料から弾き飛ばされた被加工物が前記水晶振動子に付着することによって変化する前記水晶振動子の発振周波数に基づき前記イオンビーム特性を計測するイオンミリング装置。 - 請求項1において、
前記イオンガンは、
前記イオン化室にガスを供給するガス供給源と、
互いに対向して配置される第1のカソード及び第2のカソードと、
前記第1のカソードと前記第2のカソードとの間に配置されるカソードリングと、
前記カソードリングに電気的に絶縁された状態で配置され、前記第1のカソード及び前記第2のカソードの電位に対して正電圧が印加されるアノードとを備え、
前記イオン化室は、前記第1のカソード、前記第2のカソード及び前記アノードに囲まれた領域であり、
前記磁場発生装置の前記磁路は、前記カソードリングを囲むように開口が設けられるイオンミリング装置。 - 請求項9において、
前記磁場発生装置の前記電磁コイルは、前記真空チャンバーの外側に設けられるイオンミリング装置。
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JPS53300U (ja) * | 1976-06-22 | 1978-01-05 | ||
JPH02109244A (ja) * | 1988-10-17 | 1990-04-20 | Sony Corp | イオンビーム装置 |
JP2002216653A (ja) * | 2001-01-23 | 2002-08-02 | Hitachi Ltd | イオンビーム分布制御方法およびイオンビーム処理装置 |
JP2009245880A (ja) * | 2008-03-31 | 2009-10-22 | Mitsui Eng & Shipbuild Co Ltd | イオン注入装置、イオン注入方法及びプログラム |
JP2015220352A (ja) * | 2014-05-19 | 2015-12-07 | 東京エレクトロン株式会社 | プラズマ処理装置 |
WO2021038650A1 (ja) * | 2019-08-23 | 2021-03-04 | 株式会社日立ハイテク | イオンミリング装置及びそれを用いたミリング加工方法 |
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JPS53114661A (en) | 1977-03-17 | 1978-10-06 | Toshiba Corp | Ion source of penning discharge type |
JP6220749B2 (ja) | 2014-07-30 | 2017-10-25 | 株式会社日立ハイテクノロジーズ | イオンガン及びイオンミリング装置、イオンミリング方法 |
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JPS53300U (ja) * | 1976-06-22 | 1978-01-05 | ||
JPH02109244A (ja) * | 1988-10-17 | 1990-04-20 | Sony Corp | イオンビーム装置 |
JP2002216653A (ja) * | 2001-01-23 | 2002-08-02 | Hitachi Ltd | イオンビーム分布制御方法およびイオンビーム処理装置 |
JP2009245880A (ja) * | 2008-03-31 | 2009-10-22 | Mitsui Eng & Shipbuild Co Ltd | イオン注入装置、イオン注入方法及びプログラム |
JP2015220352A (ja) * | 2014-05-19 | 2015-12-07 | 東京エレクトロン株式会社 | プラズマ処理装置 |
WO2021038650A1 (ja) * | 2019-08-23 | 2021-03-04 | 株式会社日立ハイテク | イオンミリング装置及びそれを用いたミリング加工方法 |
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