WO2024053074A1 - Ion milling device and method for processing specimen - Google Patents

Ion milling device and method for processing specimen Download PDF

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Publication number
WO2024053074A1
WO2024053074A1 PCT/JP2022/033810 JP2022033810W WO2024053074A1 WO 2024053074 A1 WO2024053074 A1 WO 2024053074A1 JP 2022033810 W JP2022033810 W JP 2022033810W WO 2024053074 A1 WO2024053074 A1 WO 2024053074A1
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temperature
sample
shielding plate
fixing part
plate fixing
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PCT/JP2022/033810
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French (fr)
Japanese (ja)
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健人 堀之内
翔太 会田
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株式会社日立ハイテク
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Priority to PCT/JP2022/033810 priority Critical patent/WO2024053074A1/en
Publication of WO2024053074A1 publication Critical patent/WO2024053074A1/en

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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
    • H01J37/02—Details
    • H01J37/20—Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support
    • 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 and a sample processing method.
  • Ion milling equipment irradiates a sample to be observed with an electron microscope (e.g., metal, semiconductor, glass, ceramic, etc.) with an unfocused ion beam, and uses a sputtering phenomenon to knock off atoms on the sample surface, creating a stress-free and stress-free milling system.
  • an electron microscope e.g., metal, semiconductor, glass, ceramic, etc.
  • This is a device that can polish the surface of a sample and expose the internal structure of the sample.
  • the sample surface and internal structure of the sample polished by ion beam irradiation serve as observation surfaces for scanning electron microscopes and transmission electron microscopes.
  • Patent Document 1 relates to a processing device that uses an ion beam to cut a portion protruding from a mask, and uses a sample that has a low melting point, such as a polymer material, and is susceptible to damage to the sample structure such as deformation or shrinkage due to heat generated by the energy of the ion beam.
  • processing apparatuses have been disclosed in which a cooling mechanism is connected to a mask brought into contact with a sample, or a cooling mechanism is provided on a sample stage.
  • samples processed by the ion milling device there are samples such as paper and polymer materials that are affected by thermal damage due to temperature rise due to ion beam irradiation.
  • thermal damage is melting or deformation of a sample due to ion beam irradiation.
  • One way to suppress thermal damage to the sample is to reduce the amount of protrusion of the sample irradiated with the ion beam from the mask (shielding plate).
  • an ion source irradiates the sample with an unfocused ion beam.
  • the shielding plate By reducing the amount of protrusion from the shielding plate, it is possible to suppress irradiation of the sample with a low energy density ion beam that makes little contribution to sample processing, and to suppress heating of the sample.
  • this method if the observation surface is located deep within the sample, it is necessary to repeatedly adjust the boundary position between the sample and the shielding plate and process the sample.
  • Patent Document 1 discloses cooling the mask and sample stage, but the purpose is to cool the sample, and does not disclose or suggest adjusting the boundary position between the sample and the shielding plate using heat. .
  • An ion milling apparatus that is an embodiment of the present invention includes a sample stage on which a sample is placed, a sample stage and a shielding plate fixing part supported by the sample stage, and a shielding plate fixed to the shielding plate fixing part. , an ion source that irradiates an unfocused ion beam toward the sample, and a temperature adjustment unit that is connected to the shield plate fixing part by a heat transfer cable and adjusts the temperature of the shield plate fixing part, and the sample is The sample is held between a shielding plate and a sample stage, and the amount of protrusion of the sample from the shielding plate is adjusted by the set temperature of the shielding plate fixing part set in the temperature adjustment unit.
  • FIG. 2 is a schematic diagram showing an ion source and a power supply circuit that applies a control voltage to the ion source.
  • FIG. 7 is a schematic diagram showing the amount of protrusion of the sample relative to the shielding plate for each temperature of the shielding plate fixing part.
  • 3 is a flowchart showing sample processing operations in Example 1.
  • FIG. 3 is a flowchart showing sample processing operations in Example 2. It is another example of a structure (schematic diagram) of an ion milling apparatus.
  • FIG. 1 is a schematic diagram showing the main parts of the ion milling device 100 from the side.
  • the ion milling apparatus 100 includes an ion source 101, a sample stage 102, a sample stage 103, a sample 104, a shielding plate 105, a shielding plate fixing part 106, a heat transfer cable 107, a temperature adjustment unit 108, and a first It has a thermocouple 109, a control section 110, a high voltage power supply 111, a supply gas control section 112, an exhaust mechanism 113, and a sample chamber 114.
  • the ion milling device 100 is used as a preprocessing device for observing the surface or cross section of a sample using a scanning electron microscope or a transmission electron microscope. In many cases, an effective penning method is used to do this.
  • the Penning method is adopted for the ion source 101, and an unfocused ion beam is irradiated from the ion source 101 toward the sample 104.
  • the control unit 110 controls the output of the ion beam by adjusting the voltage applied to the electrodes inside the ion source 101 from the high-voltage power supply 111 and the flow rate of argon gas supplied from the supply gas control unit 112.
  • the sample 104 is placed on the sample stage 103.
  • the shielding plate 105 is fixed to the shielding plate fixing part 106 by a shielding plate fixing screw 117, and the shielding plate fixing part 106 is supported by the sample stage 103.
  • the sample 104 is sandwiched between the sample stage 102 supported by the sample stage 103 and the shielding plate 105, and is made to protrude from the shielding plate 105 by a predetermined protrusion amount.
  • the sample 104 can be freely placed on the sample stage 103 in five directions (X-axis direction, Y-axis direction, Z-axis direction, rotation direction around the Y-axis, rotation direction around the X-axis) or a part thereof.
  • a driving mechanism may be provided.
  • the shielding plate fixing part 106 in order to adjust the amount of protrusion of the sample 104 from the shield plate 105, thermal contraction of the shield plate fixing part 106 is used. For this reason, it is desirable that the shielding plate fixing part 106 be made of a material with as large a coefficient of linear expansion as possible. For example, it is made of phosphor bronze, brass, etc.
  • the shielding plate fixing part 106 is connected to a temperature adjustment unit 108 via a heat transfer cable 107, and the temperature adjusting unit 108 adjusts the temperature of the shielding plate fixing part 106 to the temperature set by the control part 110.
  • the temperature adjustment method of the temperature adjustment unit 108 is various, and is not limited to a specific temperature adjustment method.
  • the temperature adjustment unit has at least a cooling function.
  • the shield plate fixing part 106 can be cooled using liquid nitrogen or dry ice.
  • the temperature adjustment unit 108 may have both a cooling function and a heating function. For example, cooling as described above and heating by a heater may be combined, or a Peltier element may be used.
  • the heat transfer cable 107 is made of a material with high heat transfer properties such as copper. Since the sample chamber 114 is maintained at a high vacuum ( ⁇ 1.0 ⁇ 10 ⁇ 3 Pa) during the milling process by the exhaust mechanism 113, there is no need to consider heat radiation from the heat transfer cable 107. The same applies to the shielding plate fixing portion 106 in this respect. Temperature control of the shield plate fixing part 106 is performed by a first thermocouple 109. When the temperature measured by the first thermocouple 109 shows a large deviation from the set temperature, the temperature control unit 108 adjusts the temperature. be adjusted. Note that the thermocouple is an example of a thermometer, and does not need to be a thermocouple as long as it can measure the temperature of the shield plate fixing part 106.
  • FIG. 2 is a schematic diagram showing an ion source 101 employing the Penning method and a power supply circuit that applies a control voltage to electrode parts of the ion source 101.
  • the power supply circuit is part of the high voltage power supply 111.
  • the ion source 101 has a first cathode 201, a second cathode 202, an anode 203, a permanent magnet 204, an accelerating electrode 205, and a gas pipe 206.
  • Argon gas is injected into the ion source 101 through the gas pipe 206 to generate an ion beam.
  • a first cathode 201 and a second cathode 202 having the same potential are arranged facing each other, and an anode 203 is arranged between the first cathode 201 and the second cathode 202. There is.
  • Electrons are generated by applying a discharge voltage Vd from the high voltage power supply 111 between the cathodes 201, 202 and the anode 203.
  • the electrons are retained by a permanent magnet 204 disposed within the ion source 101 and collide with argon gas injected from a gas pipe 206 to generate argon ions.
  • An accelerating voltage Va is applied between the anode 203 and the accelerating electrode 205 from the high voltage power supply 111, and the generated argon ions are attracted to the accelerating electrode 205 and emitted as an ion beam.
  • FIG. 3 is a schematic diagram showing the protrusion amount ⁇ H of the sample 104 with respect to the shielding plate 105 for each temperature of the shielding plate fixing part 106 as states 301 to 303.
  • the temperatures of the shield plate fixing portion 106 in states 301 to 303 are 25° C., 0° C., and ⁇ 25° C., respectively. Since the shielding plate 105 and the sample 104 are only in close contact with each other, cooling or heating the shielding plate fixing part 106 causes the shielding plate fixing part 106 and the shielding plate 105 to expand and contract, thereby causing the shielding plate 105 and the sample 104 to The boundary (edge) of moves. As a result, the distance (protrusion amount) ⁇ H from the edge to the end face of the sample 104 changes.
  • the protrusion amount ⁇ H of the sample 104 with respect to the shielding plate 105 is ⁇ h
  • the total length of the shielding plate fixing part 106 is L1
  • the shielding from the bottom of the shielding plate fixing part 106 is set.
  • the distance to the plate fixing screw 117 is L3
  • the linear expansion coefficient of the shielding plate fixing portion 106 is ⁇ 1.
  • the total length of the shielding plate 105 is L2
  • the distance from the shielding plate fixing screw 117 to the end face of the shielding plate 105 is L4
  • the linear expansion coefficient of the shielding plate 105 is ⁇ 2.
  • the temperature difference from the state 301 is 25°C. It contracts by ⁇ 2 ⁇ L2.
  • the position of the shielding plate 105 is lowered due to the thermal contraction of the shielding plate fixing portion 106, and the shielding plate 105 itself also contracts due to the thermal contraction, so that the protrusion amount ⁇ H in the state 302 is expressed as (Formula 1).
  • the first term is the amount of protrusion in state 301
  • the second term is the amount of change in the position of the shield plate fixing screw 117 due to thermal contraction of the shield plate fixing part 106
  • the third term is the amount of change in the position of the shield plate fixing screw 117 due to thermal contraction of the shield plate fixing part 106. It represents the amount of shrinkage of the shielding plate 105 with the shielding plate fixing screw 117 as a fulcrum due to thermal contraction.
  • the protrusion amount ⁇ H also depends on the support structure of the shielding plate fixing portion 106 and the shielding plate 105.
  • the support structure for the shielding plate fixing part 106 and the shielding plate 105 shown in the schematic diagram of FIG. 3 is an example, and the present embodiment is not limited to a specific support structure.
  • the flowchart shown in FIG. 4 shows a series of operations from the start to the end of sample processing in the ion milling apparatus of Example 1. A series of operations in this flowchart are executed by the control unit 110. Details of each operation are described below.
  • the sample processing conditions include the sample protrusion amount ⁇ h of the sample 104 with respect to the shielding plate 105 at the start of the milling process, and it is desirable that the sample protrusion amount ⁇ h to be set is set to a value as small as possible.
  • the control unit 110 sets the temperature (referred to as set temperature) that corresponds to the sample protrusion amount ⁇ h set in step S01, and uses the temperature adjustment unit 108 to adjust the temperature of the shielding plate fixing unit 106 to the set temperature.
  • set temperature the temperature that corresponds to the sample protrusion amount ⁇ h set in step S01
  • uses the temperature adjustment unit 108 to adjust the temperature of the shielding plate fixing unit 106 to the set temperature.
  • the sample 104 is sandwiched between the shielding plate 105 and the sample stage 102 so that the amount of protrusion from the shielding plate becomes ⁇ h at room temperature. This makes it unnecessary to adjust the temperature of the shielding plate fixing section 106 at the start of milling.
  • the sample 104 is processed (milling process) by irradiating the sample 104 with an ion beam from the ion source 101.
  • S04 During the milling process, the temperature of the shield plate fixing part 106 is monitored with the first thermocouple 109. If the temperature of the shielding plate fixing part 106 is out of the allowable range of the set temperature due to heating caused by long-time milling processing, processing is temporarily stopped and the process returns to S02 to cool the shielding plate fixing part 106. conduct. As soon as the temperature of the shield plate fixing part 106 returns to the set temperature set in step S02, processing is restarted (S03).
  • S05 Check whether all parts of the sample 104 protruding from the shielding plate 105 have been shaved off. If it is not shaved, processing continues (S03).
  • the confirmation method is not limited. As the simplest method, it may be determined that the protruding portion has been removed when a predetermined machining time has elapsed. A transparent window may be provided in the sample chamber, and direct confirmation may be made through the window using a monitoring means such as an optical microscope or an electron microscope. Alternatively, the processing amount may be estimated from the amount of sputtered particles generated during sample processing.
  • Example 1 by adjusting the temperature of the shielding plate fixing part 106, the minute amount of protrusion of the sample from the shielding plate can be adjusted using a simple mechanism. Thereby, by performing the cross-section milling process with the amount of protrusion as small as possible, it is possible to minimize the heat load on the sample 104 accompanying the cross-section milling process. Thereby, thermal damage caused by ion beam irradiation to the sample 104 can be suppressed.
  • the temperature of the shielding plate fixing part 106 at a time when the ion beam is not irradiated before the start of processing is stored as the reference temperature. If the temperature of the shield plate fixing part 106 deviates from the reference temperature due to ion beam irradiation after the start of processing, the temperature adjustment unit 108 adjusts the temperature of the shield plate fixing part 106 to the reference temperature.
  • the flowchart shown in FIG. 5 shows a series of operations from the start to the end of sample processing in the ion milling apparatus of Example 2. A series of operations in this flowchart are executed by the control unit 110. Details of each operation are described below.
  • S11 Set sample processing conditions of the ion milling apparatus 100 (acceleration voltage of the ion source 101, discharge voltage, supply amount of argon gas, etc.). If this processing is a pretreatment for observing the cross section of the sample 104 using a scanning electron microscope or a transmission electron microscope, the cross section that will be the observation surface should be located at the boundary (edge) between the shielding plate 105 and the sample 104. Next, the sample 104 is sandwiched between the shielding plate 105 and the sample stage 102. As the sample processing conditions, the sample processing time required for milling the area of the sample 104 set up in this manner that protrudes from the shielding plate 105 is set.
  • the sample 104 is processed (milling process) by irradiating the sample 104 with an ion beam from the ion source 101.
  • the temperature adjustment unit 108 adjusts the temperature so that the shield plate fixing part 106 reaches the reference temperature, and continues processing.
  • the ion milling apparatus 100 includes the thermocouple 109, which is a first thermometer that measures the temperature of the shielding plate fixing part 106, and the control part 110, in which the sample processing time is set.
  • 110 stores the temperature of the shielding plate fixing part 106 measured by the thermocouple 109 as a first thermometer before irradiation with the ion beam from the ion source 101 as a reference temperature, and stores the temperature during the ion beam irradiation from the ion source 101.
  • the temperature adjustment unit 108 maintains the temperature of the shield plate fixing portion 106 measured by the thermocouple 109, which is the first thermometer, at the reference temperature. This makes it possible to provide an ion milling device that can control the minute amount of protrusion of the sample relative to the shielding plate with a simple mechanism.
  • FIG. 6 shows a modification of the ion milling device. Components common to those of the ion milling apparatus shown in FIG. 1 are indicated using the same reference numerals, and redundant explanation will be omitted.
  • a second thermocouple 116 for checking the temperature of the sample 104 is added to the ion milling apparatus 200.
  • a thermometer other than a thermocouple may also be used for the second thermocouple 116.
  • the present invention made by the present inventor has been specifically explained based on the embodiments, but the present invention is not limited to the described embodiments, and various changes can be made without departing from the gist thereof. .
  • the temperature of the shielding plate 105 may be adjusted directly.
  • the present invention is not limited to the embodiments described above, and includes various modifications.
  • the embodiments described above are described in detail to make the present invention easier to understand, and the present invention is not necessarily limited to having all the configurations described.
  • thermocouple 110: control unit, 111: high voltage power supply, 112: supply gas control unit, 113: exhaust mechanism, 114: sample chamber, 116: second thermocouple, 117: shield plate fixing screw , 201: first cathode, 202: second cathode, 203: anode, 204: permanent magnet, 205: accelerating electrode, 206: gas piping.

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  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
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Abstract

This ion milling device comprises: a specimen stage (103) on which a specimen is to be placed; a specimen table (102) and a shielding-plate-fixing part (106) which are supported by the specimen stage; a shielding plate (105) fixed to the shielding-plate-fixing part; an ion source (101) which emits an unfocused ion beam toward the specimen; and a temperature regulation unit (108) which is connected to the shielding-plate-fixing part by a heat transfer cable (107) and which regulates the temperature of the shielding-plate-fixing part. The specimen is sandwiched between the shielding plate and the specimen table and held thereby, and the amount in which the specimen protrudes from the shielding plate is regulated in accordance with temperatures of the shielding-plate-fixing part which are set by the temperature regulation unit.

Description

イオンミリング装置及び試料加工方法Ion milling device and sample processing method
　本発明は、イオンミリング装置及び試料加工方法に関する。 The present invention relates to an ion milling device and a sample processing method.
　イオンミリング装置は、電子顕微鏡観察対象である試料（例えば、金属、半導体、ガラス、セラミックなど）に対して非集束のイオンビームを照射し、スパッタリング現象によって試料表面の原子を弾き飛ばし、無応力で試料表面の研磨や試料の内部構造を露出できる装置である。イオンビーム照射によって研磨した試料表面や試料の内部構造は、走査電子顕微鏡や透過電子顕微鏡の観察面となる。 Ion milling equipment irradiates a sample to be observed with an electron microscope (e.g., metal, semiconductor, glass, ceramic, etc.) with an unfocused ion beam, and uses a sputtering phenomenon to knock off atoms on the sample surface, creating a stress-free and stress-free milling system. This is a device that can polish the surface of a sample and expose the internal structure of the sample. The sample surface and internal structure of the sample polished by ion beam irradiation serve as observation surfaces for scanning electron microscopes and transmission electron microscopes.
　特許文献１は、イオンビームによりマスクから突出した部分を削る加工装置に関し、高分子材料のように融点が低く、イオンビームのエネルギーによる熱により変形や収縮といった試料構造の損傷を生じやすい試料である場合に、熱ダメージの発生を防止するため、試料に接触させるマスクに冷却機構を接続させる、または試料台に冷却機構を備える加工装置が開示されている。 Patent Document 1 relates to a processing device that uses an ion beam to cut a portion protruding from a mask, and uses a sample that has a low melting point, such as a polymer material, and is susceptible to damage to the sample structure such as deformation or shrinkage due to heat generated by the energy of the ion beam. In order to prevent thermal damage from occurring in such cases, processing apparatuses have been disclosed in which a cooling mechanism is connected to a mask brought into contact with a sample, or a cooling mechanism is provided on a sample stage.
特開２０１０－２５７８５６号公報Japanese Patent Application Publication No. 2010-257856
　イオンミリング装置の加工対象とする試料の中には、紙や高分子材料等のようにイオンビーム照射による温度上昇による熱ダメージの影響を受ける試料がある。熱ダメージの一例として、イオンビーム照射による試料の溶融や変形などがある。 Among the samples processed by the ion milling device, there are samples such as paper and polymer materials that are affected by thermal damage due to temperature rise due to ion beam irradiation. An example of thermal damage is melting or deformation of a sample due to ion beam irradiation.
　試料への熱ダメージを抑制する方法として、イオンビームが照射される試料のマスク（遮蔽板）からの突出量を小さくすることが挙げられる。試料加工時には、イオン源から非集束のイオンビームが試料に向けて照射される。遮蔽板からの突出量を小さくすることで、試料加工への寄与の少ないエネルギー密度の低いイオンビームが試料に照射されるのを抑制し、試料の加熱を抑えることができる。しかしながら、この手法では、観察面が試料の深いところに存在する場合には、試料と遮蔽板の境界位置の調整及び試料の加工を繰り返し行う必要がある。 One way to suppress thermal damage to the sample is to reduce the amount of protrusion of the sample irradiated with the ion beam from the mask (shielding plate). When processing a sample, an ion source irradiates the sample with an unfocused ion beam. By reducing the amount of protrusion from the shielding plate, it is possible to suppress irradiation of the sample with a low energy density ion beam that makes little contribution to sample processing, and to suppress heating of the sample. However, in this method, if the observation surface is located deep within the sample, it is necessary to repeatedly adjust the boundary position between the sample and the shielding plate and process the sample.
　発明者らは、イオンミリング装置における試料と遮蔽板の境界位置の調整を簡易な機構で実現する検討を進め、本発明に至った。特許文献１は、マスクや試料台を冷却することを開示するが、試料の冷却を目的とするものであり、熱を用いた試料と遮蔽板の境界位置の調整を開示、示唆するものではない。 The inventors have conducted studies to realize the adjustment of the boundary position between the sample and the shielding plate in an ion milling device using a simple mechanism, and have arrived at the present invention. Patent Document 1 discloses cooling the mask and sample stage, but the purpose is to cool the sample, and does not disclose or suggest adjusting the boundary position between the sample and the shielding plate using heat. .
　本発明の一実施の形態であるイオンミリング装置は、試料が載置される試料ステージと、試料ステージによって支持される試料台及び遮蔽板固定部と、遮蔽板固定部に固定される遮蔽板と、試料に向けて非集束のイオンビームを照射するイオン源と、遮蔽板固定部と伝熱ケーブルによって接続され、遮蔽板固定部の温度を調整する温度調整ユニットと、を有し、試料は、遮蔽板と試料台との間に挟み込まれて保持され、試料の遮蔽板からの突出量は、温度調整ユニットに設定される遮蔽板固定部の設定温度によって調整される。 An ion milling apparatus that is an embodiment of the present invention includes a sample stage on which a sample is placed, a sample stage and a shielding plate fixing part supported by the sample stage, and a shielding plate fixed to the shielding plate fixing part. , an ion source that irradiates an unfocused ion beam toward the sample, and a temperature adjustment unit that is connected to the shield plate fixing part by a heat transfer cable and adjusts the temperature of the shield plate fixing part, and the sample is The sample is held between a shielding plate and a sample stage, and the amount of protrusion of the sample from the shielding plate is adjusted by the set temperature of the shielding plate fixing part set in the temperature adjustment unit.
　簡素な機構で、遮蔽板に対する試料の微小な突出量を制御可能なイオンミリング装置を提供する。その他の課題と新規な特徴は、本明細書の記述および添付図面から明らかになるであろう。 To provide an ion milling device that can control the minute amount of protrusion of a sample relative to a shielding plate with a simple mechanism. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.
イオンミリング装置の構成例（模式図）である。It is a configuration example (schematic diagram) of an ion milling device. イオン源とイオン源に制御電圧を印加する電源回路とを示す模式図である。FIG. 2 is a schematic diagram showing an ion source and a power supply circuit that applies a control voltage to the ion source. 遮蔽板固定部の温度ごとに遮蔽板に対する試料の突出量を示す模式図である。FIG. 7 is a schematic diagram showing the amount of protrusion of the sample relative to the shielding plate for each temperature of the shielding plate fixing part. 実施例１の試料加工の操作を示すフローチャートである。3 is a flowchart showing sample processing operations in Example 1. FIG. 実施例２の試料加工の操作を示すフローチャートである。3 is a flowchart showing sample processing operations in Example 2. イオンミリング装置の別の構成例（模式図）である。It is another example of a structure (schematic diagram) of an ion milling apparatus.
　以下、本発明の実施例を図面に基づいて説明する。 Hereinafter, embodiments of the present invention will be described based on the drawings.
　図１は、イオンミリング装置１００の主要部を側面から示した模式図である。図１では、鉛直方向をＹ方向として表示している。イオンミリング装置１００は、その主要な構成として、イオン源１０１、試料台１０２、試料ステージ１０３、試料１０４、遮蔽板１０５、遮蔽板固定部１０６、伝熱ケーブル１０７、温度調整ユニット１０８、第１の熱電対１０９、制御部１１０、高圧電源１１１、供給ガス制御部１１２、排気機構１１３、試料室１１４を有する。 FIG. 1 is a schematic diagram showing the main parts of the ion milling device 100 from the side. In FIG. 1, the vertical direction is shown as the Y direction. The ion milling apparatus 100 includes an ion source 101, a sample stage 102, a sample stage 103, a sample 104, a shielding plate 105, a shielding plate fixing part 106, a heat transfer cable 107, a temperature adjustment unit 108, and a first It has a thermocouple 109, a control section 110, a high voltage power supply 111, a supply gas control section 112, an exhaust mechanism 113, and a sample chamber 114.
　イオンミリング装置１００は、走査電子顕微鏡や透過電子顕微鏡による試料の表面あるいは断面を観察するための前処理装置として用いられており、このような前処理装置向けのイオン源には、構造を小型化するために有効なペニング方式を採用する場合が多い。本実施例でもイオン源１０１にはペニング方式が採用されており、イオン源１０１から試料１０４に向けて非集束のイオンビームが照射される。制御部１１０は、高圧電源１１１からイオン源１０１内部の電極に印加する電圧、供給ガス制御部１１２から供給されるアルゴンガス流量を調整して、イオンビームの出力を制御する。 The ion milling device 100 is used as a preprocessing device for observing the surface or cross section of a sample using a scanning electron microscope or a transmission electron microscope. In many cases, an effective penning method is used to do this. In this embodiment as well, the Penning method is adopted for the ion source 101, and an unfocused ion beam is irradiated from the ion source 101 toward the sample 104. The control unit 110 controls the output of the ion beam by adjusting the voltage applied to the electrodes inside the ion source 101 from the high-voltage power supply 111 and the flow rate of argon gas supplied from the supply gas control unit 112.
　試料１０４は試料ステージ１０３上に載置される。遮蔽板１０５は遮蔽板固定ねじ１１７によって遮蔽板固定部１０６に固定され、遮蔽板固定部１０６は試料ステージ１０３によって支持されている。試料１０４は、試料ステージ１０３によって支持される試料台１０２と遮蔽板１０５との間に挟み込まれ、遮蔽板１０５から所定の突出量だけ突出させられる。なお、試料ステージ１０３に試料１０４を５方向（Ｘ軸方向、Ｙ軸方向、Ｚ軸方向、Ｙ軸を中心とする回転方向、Ｘ軸を中心とする回転方向）あるいはその一部に、自由に駆動する駆動機構を設けてもよい。 The sample 104 is placed on the sample stage 103. The shielding plate 105 is fixed to the shielding plate fixing part 106 by a shielding plate fixing screw 117, and the shielding plate fixing part 106 is supported by the sample stage 103. The sample 104 is sandwiched between the sample stage 102 supported by the sample stage 103 and the shielding plate 105, and is made to protrude from the shielding plate 105 by a predetermined protrusion amount. Note that the sample 104 can be freely placed on the sample stage 103 in five directions (X-axis direction, Y-axis direction, Z-axis direction, rotation direction around the Y-axis, rotation direction around the X-axis) or a part thereof. A driving mechanism may be provided.
　本実施例では、遮蔽板１０５からの試料１０４の突出量を調整するために、遮蔽板固定部１０６の熱収縮を利用する。このため、遮蔽板固定部１０６はできるだけ線膨張係数が大きい材料で作成することが望ましい。例えば、リン青銅、黄銅などで作製する。遮蔽板固定部１０６は伝熱ケーブル１０７を介して温度調整ユニット１０８と接続されており、温度調整ユニット１０８は、遮蔽板固定部１０６を制御部１１０によって設定された温度に調整する。温度調整ユニット１０８の温度調整方式は様々であり、特定の温度調整方式に限定されない。イオンビームが照射されることにより、試料１０４と遮蔽板１０５は加熱され、伝熱により遮蔽板固定部１０６の温度は上昇する。このため、温度調整ユニットは、少なくとも冷却機能を備える。例えば、液体窒素やドライアイスを用いて遮蔽板固定部１０６を冷却することができる。一方、制御できる温度は広範囲であるほど制御の自由度が増すため、温度調整ユニット１０８は冷却機能と加温機能の双方を備えていてもよい。例えば、上述のような冷却とヒータによる加熱とを組み合わせてもよく、ペルチェ素子を用いてもよい。 In this embodiment, in order to adjust the amount of protrusion of the sample 104 from the shield plate 105, thermal contraction of the shield plate fixing part 106 is used. For this reason, it is desirable that the shielding plate fixing part 106 be made of a material with as large a coefficient of linear expansion as possible. For example, it is made of phosphor bronze, brass, etc. The shielding plate fixing part 106 is connected to a temperature adjustment unit 108 via a heat transfer cable 107, and the temperature adjusting unit 108 adjusts the temperature of the shielding plate fixing part 106 to the temperature set by the control part 110. The temperature adjustment method of the temperature adjustment unit 108 is various, and is not limited to a specific temperature adjustment method. By being irradiated with the ion beam, the sample 104 and the shielding plate 105 are heated, and the temperature of the shielding plate fixing part 106 increases due to heat transfer. Therefore, the temperature adjustment unit has at least a cooling function. For example, the shield plate fixing part 106 can be cooled using liquid nitrogen or dry ice. On the other hand, the wider the temperature range that can be controlled, the greater the degree of freedom in control, so the temperature adjustment unit 108 may have both a cooling function and a heating function. For example, cooling as described above and heating by a heater may be combined, or a Peltier element may be used.
　伝熱ケーブル１０７は、銅などの伝熱性が大きい材料で作製する。試料室１１４は排気機構１１３によってミリング処理時には高真空（＜１．０×１０－３Ｐａ）に保たれているため、伝熱ケーブル１０７からの放熱は考慮する必要はない。この点は遮蔽板固定部１０６も同様である。遮蔽板固定部１０６の温度管理は、第１の熱電対１０９で行われ、第１の熱電対１０９で測定された温度が設定温度と大きな乖離が見られたときは、温度調整ユニット１０８によって温度調整される。なお、熱電対は温度計の一例であり、遮蔽板固定部１０６の温度を測定できれば熱電対でなくてもよい。 The heat transfer cable 107 is made of a material with high heat transfer properties such as copper. Since the sample chamber 114 is maintained at a high vacuum (<1.0×10 −3 Pa) during the milling process by the exhaust mechanism 113, there is no need to consider heat radiation from the heat transfer cable 107. The same applies to the shielding plate fixing portion 106 in this respect. Temperature control of the shield plate fixing part 106 is performed by a first thermocouple 109. When the temperature measured by the first thermocouple 109 shows a large deviation from the set temperature, the temperature control unit 108 adjusts the temperature. be adjusted. Note that the thermocouple is an example of a thermometer, and does not need to be a thermocouple as long as it can measure the temperature of the shield plate fixing part 106.
　図２は、ペニング方式を採用したイオン源１０１と、イオン源１０１の電極部品に制御電圧を印加する電源回路とを示す模式図である。電源回路は高圧電源１１１の一部である。 FIG. 2 is a schematic diagram showing an ion source 101 employing the Penning method and a power supply circuit that applies a control voltage to electrode parts of the ion source 101. The power supply circuit is part of the high voltage power supply 111.
　イオン源１０１は、第１カソード２０１、第２カソード２０２、アノード２０３、永久磁石２０４、加速電極２０５、ガス配管２０６を有する。イオンビームを発生させるため、ガス配管２０６を通してイオン源１０１内部にアルゴンガスが注入される。イオン源１０１内部には、同電位とされる第１カソード２０１及び第２カソード２０２が対向して配置されており、第１カソード２０１と第２カソード２０２との間にはアノード２０３が配置されている。カソード２０１，２０２とアノード２０３との間に高圧電源１１１から放電電圧Ｖｄが印加されることにより電子が発生する。電子はイオン源１０１内に配置された永久磁石２０４によって滞留し、ガス配管２０６から注入されたアルゴンガスと衝突してアルゴンイオンを生成する。アノード２０３と加速電極２０５との間には高圧電源１１１から加速電圧Ｖａが印加されており、生成されたアルゴンイオンは加速電極２０５に誘引され、イオンビームとして放出される。 The ion source 101 has a first cathode 201, a second cathode 202, an anode 203, a permanent magnet 204, an accelerating electrode 205, and a gas pipe 206. Argon gas is injected into the ion source 101 through the gas pipe 206 to generate an ion beam. Inside the ion source 101, a first cathode 201 and a second cathode 202 having the same potential are arranged facing each other, and an anode 203 is arranged between the first cathode 201 and the second cathode 202. There is. Electrons are generated by applying a discharge voltage Vd from the high voltage power supply 111 between the cathodes 201, 202 and the anode 203. The electrons are retained by a permanent magnet 204 disposed within the ion source 101 and collide with argon gas injected from a gas pipe 206 to generate argon ions. An accelerating voltage Va is applied between the anode 203 and the accelerating electrode 205 from the high voltage power supply 111, and the generated argon ions are attracted to the accelerating electrode 205 and emitted as an ion beam.
　図３に、遮蔽板固定部１０６の温度ごとに、遮蔽板１０５に対する試料１０４の突出量ΔＨを示す模式図を状態３０１～３０３として示す。状態３０１～３０３における遮蔽板固定部１０６の温度は、それぞれ２５℃、０℃、－２５℃である。遮蔽板１０５と試料１０４とは密着させているだけであるので、遮蔽板固定部１０６を冷却または加熱することにより遮蔽板固定部１０６及び遮蔽板１０５が伸縮することにより遮蔽板１０５と試料１０４との境界（エッジ）が移動する。これにより、エッジから試料１０４の端面までの距離（突出量）ΔＨが変化する。 FIG. 3 is a schematic diagram showing the protrusion amount ΔH of the sample 104 with respect to the shielding plate 105 for each temperature of the shielding plate fixing part 106 as states 301 to 303. The temperatures of the shield plate fixing portion 106 in states 301 to 303 are 25° C., 0° C., and −25° C., respectively. Since the shielding plate 105 and the sample 104 are only in close contact with each other, cooling or heating the shielding plate fixing part 106 causes the shielding plate fixing part 106 and the shielding plate 105 to expand and contract, thereby causing the shielding plate 105 and the sample 104 to The boundary (edge) of moves. As a result, the distance (protrusion amount) ΔH from the edge to the end face of the sample 104 changes.
　遮蔽板固定部１０６の温度が２５℃であるとき（状態３０１）、遮蔽板１０５に対する試料１０４の突出量ΔＨをΔｈ、遮蔽板固定部１０６の全長をＬ１、遮蔽板固定部１０６の底面から遮蔽板固定ねじ１１７までの距離をＬ３、遮蔽板固定部１０６の線膨張係数をα１とする。また、遮蔽板１０５の全長をＬ２、遮蔽板固定ねじ１１７から遮蔽板１０５の端面までの距離をＬ４、遮蔽板１０５の線膨張係数をα２とする。 When the temperature of the shielding plate fixing part 106 is 25° C. (state 301), the protrusion amount ΔH of the sample 104 with respect to the shielding plate 105 is Δh, the total length of the shielding plate fixing part 106 is L1, and the shielding from the bottom of the shielding plate fixing part 106 is set. The distance to the plate fixing screw 117 is L3, and the linear expansion coefficient of the shielding plate fixing portion 106 is α1. Further, the total length of the shielding plate 105 is L2, the distance from the shielding plate fixing screw 117 to the end face of the shielding plate 105 is L4, and the linear expansion coefficient of the shielding plate 105 is α2.
　遮蔽板固定部１０６の温度が０℃となるとき（状態３０２）、状態３０１からの温度差は２５℃となるため、遮蔽板固定部１０６及び遮蔽板１０５は、それぞれ２５×α１×Ｌ１、２５×α２×Ｌ２だけ収縮する。遮蔽板固定部１０６の熱収縮によって遮蔽板１０５の位置が引き下げられるとともに、遮蔽板１０５そのものも熱収縮により収縮する結果、状態３０２における突出量ΔＨは、（式１）となる。 When the temperature of the shielding plate fixing part 106 is 0°C (state 302), the temperature difference from the state 301 is 25°C. It contracts by ×α2×L2. The position of the shielding plate 105 is lowered due to the thermal contraction of the shielding plate fixing portion 106, and the shielding plate 105 itself also contracts due to the thermal contraction, so that the protrusion amount ΔH in the state 302 is expressed as (Formula 1).
　ΔＨ＝Δｈ＋２５×α１×Ｌ３＋２５×α２×Ｌ４　・・・（式１）
　（式１）の右辺において、第１項は状態３０１における突出量、第２項は遮蔽板固定部１０６の熱収縮による遮蔽板固定ねじ１１７の位置の変化量、第３項は遮蔽板１０５の熱収縮による、遮蔽板固定ねじ１１７を支点とした遮蔽板１０５の収縮量を表している。このように、突出量ΔＨは、遮蔽板固定部１０６及び遮蔽板１０５の支持構造にも依存する。図３の模式図に示す遮蔽板固定部１０６や遮蔽板１０５の支持構造は一例であり、本実施例は、特定の支持構造に限定するものではない。 ΔH=Δh+25×α1×L3+25×α2×L4 (Formula 1)
On the right side of (Equation 1), the first term is the amount of protrusion in state 301, the second term is the amount of change in the position of the shield plate fixing screw 117 due to thermal contraction of the shield plate fixing part 106, and the third term is the amount of change in the position of the shield plate fixing screw 117 due to thermal contraction of the shield plate fixing part 106. It represents the amount of shrinkage of the shielding plate 105 with the shielding plate fixing screw 117 as a fulcrum due to thermal contraction. In this way, the protrusion amount ΔH also depends on the support structure of the shielding plate fixing portion 106 and the shielding plate 105. The support structure for the shielding plate fixing part 106 and the shielding plate 105 shown in the schematic diagram of FIG. 3 is an example, and the present embodiment is not limited to a specific support structure.
　同様に、遮蔽板固定部１０６の温度が－２５℃となるとき（状態３０３）、状態３０１からの温度差は５０℃となるため、遮蔽板固定部１０６及び遮蔽板１０５は、それぞれ５０×α１×Ｌ１、５０×α２×Ｌ２だけ収縮する。状態３０３における突出量ΔＨは、（式２）で表せる。 Similarly, when the temperature of the shielding plate fixing part 106 becomes -25°C (state 303), the temperature difference from the state 301 is 50°C, so the temperature of the shielding plate fixing part 106 and the shielding plate 105 is 50×α1, respectively. xL1, contracted by 50 x α2 x L2. The protrusion amount ΔH in state 303 can be expressed by (Formula 2).
　ΔＨ＝Δｈ＋５０×α１×Ｌ３＋５０×α２×Ｌ４　・・・（式２）
　このように、試料１０４の遮蔽板１０５からの突出量ΔＨは温度差を変数とする一次関数にしたがって変化することになる。 ΔH=Δh+50×α1×L3+50×α2×L4...(Formula 2)
In this way, the amount of protrusion ΔH of the sample 104 from the shielding plate 105 changes according to a linear function with the temperature difference as a variable.
　図４に示すフローチャートは、実施例１のイオンミリング装置における試料加工開始から終了までの一連の操作を示す。本フローチャートの一連の操作は制御部１１０によって実行される。以下に、それぞれの操作の詳細について記す。 The flowchart shown in FIG. 4 shows a series of operations from the start to the end of sample processing in the ion milling apparatus of Example 1. A series of operations in this flowchart are executed by the control unit 110. Details of each operation are described below.
　Ｓ０１：イオンミリング装置１００の試料加工条件（イオン源１０１の加速電圧、放電電圧、アルゴンガスの供給量など）を設定する。試料加工条件には、ミリング処理開始時における遮蔽板１０５に対する試料１０４の試料突出量Δｈを含み、設定する試料突出量Δｈはできるだけ小さい値に設定することが望ましい。 S01: Set sample processing conditions of the ion milling apparatus 100 (acceleration voltage of the ion source 101, discharge voltage, supply amount of argon gas, etc.). The sample processing conditions include the sample protrusion amount Δh of the sample 104 with respect to the shielding plate 105 at the start of the milling process, and it is desirable that the sample protrusion amount Δh to be set is set to a value as small as possible.
　Ｓ０２：制御部１１０は、ステップＳ０１において設定した試料突出量Δｈとなる温度（設定温度という）を設定し、温度調整ユニット１０８により遮蔽板固定部１０６の温度を設定温度に調整する。なお、ステップＳ０１から続けて実施する場合は、室温において遮蔽板からの突出量がΔｈとなるように試料１０４を遮蔽板１０５と試料台１０２との間に挟み込んでおく。これにより、ミリング加工開始時には、遮蔽板固定部１０６の温度調整を不要にできる。 S02: The control unit 110 sets the temperature (referred to as set temperature) that corresponds to the sample protrusion amount Δh set in step S01, and uses the temperature adjustment unit 108 to adjust the temperature of the shielding plate fixing unit 106 to the set temperature. In addition, when performing continuously from step S01, the sample 104 is sandwiched between the shielding plate 105 and the sample stage 102 so that the amount of protrusion from the shielding plate becomes Δh at room temperature. This makes it unnecessary to adjust the temperature of the shielding plate fixing section 106 at the start of milling.
　Ｓ０３：イオン源１０１からイオンビームを試料１０４に照射することにより、試料１０４の加工（ミリング処理）を実施する。 S03: The sample 104 is processed (milling process) by irradiating the sample 104 with an ion beam from the ion source 101.
　Ｓ０４：ミリング処理中は第１の熱電対１０９で遮蔽板固定部１０６の温度をモニタリングする。長時間のミリング処理に伴う加熱のため、遮蔽板固定部１０６の温度が設定温度の許容範囲を外れている場合、一時的に加工を停止してＳ０２に戻り、遮蔽板固定部１０６の冷却を行う。遮蔽板固定部１０６の温度がステップＳ０２で設定した設定温度に戻り次第、加工を再開する（Ｓ０３）。 S04: During the milling process, the temperature of the shield plate fixing part 106 is monitored with the first thermocouple 109. If the temperature of the shielding plate fixing part 106 is out of the allowable range of the set temperature due to heating caused by long-time milling processing, processing is temporarily stopped and the process returns to S02 to cool the shielding plate fixing part 106. conduct. As soon as the temperature of the shield plate fixing part 106 returns to the set temperature set in step S02, processing is restarted (S03).
　Ｓ０５：遮蔽板１０５から突出した試料１０４の部分が全て削れているか確認する。削れていない場合は引き続き加工を実施する（Ｓ０３）。なお、確認方法については限定されない。もっとも単純な方法としてはあらかじめ定めた加工時間が経過した場合に突出部分が削れたと判断してもよい。試料室に透明な窓を設け、窓を介して光学顕微鏡あるいは電子顕微鏡等のモニタ手段により直接的に確認してもよい。あるいは試料加工に伴って生じるスパッタ粒子の量から加工量を推定してもよい。 S05: Check whether all parts of the sample 104 protruding from the shielding plate 105 have been shaved off. If it is not shaved, processing continues (S03). Note that the confirmation method is not limited. As the simplest method, it may be determined that the protruding portion has been removed when a predetermined machining time has elapsed. A transparent window may be provided in the sample chamber, and direct confirmation may be made through the window using a monitoring means such as an optical microscope or an electron microscope. Alternatively, the processing amount may be estimated from the amount of sputtered particles generated during sample processing.
　Ｓ０６：試料１０４が目的となる部分まで削れたか確認する。目的となる部分とは、例えば、本加工が走査電子顕微鏡や透過電子顕微鏡によって試料１０４の断面を観察するための前処理である場合には、観察面となる断面である。削れていない場合はステップＳ０２に戻って、試料の遮蔽板からの突出量がΔｈとなるように、遮蔽板固定部１０６の温度制御を実施する。具体的には、前回温度制御時の設定温度からΔＴだけ低い設定温度を再設定し、温度調整ユニット１０８により再設定した設定温度まで遮蔽板固定部１０６を冷却する。例えば、図３の例であれば、ΔＴ＝Δｈ／（α１Ｌ３＋α２Ｌ４）である。 S06: Check whether the sample 104 has been shaved to the target part. The target portion is, for example, a cross section that will be the observation surface when the main processing is pretreatment for observing the cross section of the sample 104 using a scanning electron microscope or a transmission electron microscope. If it is not scraped, the process returns to step S02, and the temperature of the shielding plate fixing part 106 is controlled so that the amount of protrusion of the sample from the shielding plate becomes Δh. Specifically, the set temperature is reset to be lower by ΔT than the set temperature during the previous temperature control, and the temperature adjustment unit 108 cools the shielding plate fixing portion 106 to the reset set temperature. For example, in the example of FIG. 3, ΔT=Δh/(α1L3+α2L4).
　Ｓ０７：目的となる部分まで削れていれば、加工を終了する。 S07: If the target part has been cut, the machining ends.
　以上のように、実施例１では遮蔽板固定部１０６の温度を調整することで、単純な機構により、試料の遮蔽板からの微小な突出量を調整可能とする。これにより、断面ミリング処理中は、突出量を可能な限り小さくした状態で行うことにより、断面ミリング処理に伴う試料１０４への熱負荷を最低限にすることが可能になる。これにより、試料１０４へのイオンビーム照射に伴う熱ダメージを抑えることができる。 As described above, in Example 1, by adjusting the temperature of the shielding plate fixing part 106, the minute amount of protrusion of the sample from the shielding plate can be adjusted using a simple mechanism. Thereby, by performing the cross-section milling process with the amount of protrusion as small as possible, it is possible to minimize the heat load on the sample 104 accompanying the cross-section milling process. Thereby, thermal damage caused by ion beam irradiation to the sample 104 can be suppressed.
　実施例２として、遮蔽板１０５へのイオンビーム照射による温度ドリフトの影響を低減可能なイオンミリング装置について説明する。実施例２のイオンミリング装置のハードウェア構成は、図１に示したイオンミリング装置１００と同一であるので、重複する説明は省略する。実施例２においては、加工開始前のイオンビーム非照射時の遮蔽板固定部１０６の温度を基準温度として記憶する。加工開始後のイオンビーム照射により遮蔽板固定部１０６の温度が基準温度から外れた場合、温度調整ユニット１０８は遮蔽板固定部１０６の温度が基準温度になるよう調整する。これにより、断面ミリング処理中における遮蔽板１０５の温度ドリフトによる影響を低減することができ、遮蔽板１０５と試料１０４との境界（エッジ）の位置を加工開始時の位置に保った状態で加工を実施できる。 As a second embodiment, an ion milling apparatus that can reduce the influence of temperature drift due to ion beam irradiation on the shielding plate 105 will be described. The hardware configuration of the ion milling apparatus of Example 2 is the same as that of the ion milling apparatus 100 shown in FIG. 1, so a duplicate explanation will be omitted. In the second embodiment, the temperature of the shielding plate fixing part 106 at a time when the ion beam is not irradiated before the start of processing is stored as the reference temperature. If the temperature of the shield plate fixing part 106 deviates from the reference temperature due to ion beam irradiation after the start of processing, the temperature adjustment unit 108 adjusts the temperature of the shield plate fixing part 106 to the reference temperature. This makes it possible to reduce the influence of temperature drift of the shielding plate 105 during the cross-sectional milling process, and the machining can be performed while maintaining the position of the boundary (edge) between the shielding plate 105 and the sample 104 at the position at the start of machining. Can be implemented.
　図５に示すフローチャートは、実施例２のイオンミリング装置における試料加工開始から終了までの一連の操作を示す。本フローチャートの一連の操作は制御部１１０によって実行される。以下に、それぞれの操作の詳細について記す。 The flowchart shown in FIG. 5 shows a series of operations from the start to the end of sample processing in the ion milling apparatus of Example 2. A series of operations in this flowchart are executed by the control unit 110. Details of each operation are described below.
　Ｓ１１：イオンミリング装置１００の試料加工条件（イオン源１０１の加速電圧、放電電圧、アルゴンガスの供給量など）を設定する。本加工が走査電子顕微鏡や透過電子顕微鏡によって試料１０４の断面を観察するための前処理である場合には、観察面となる断面が遮蔽板１０５と試料１０４との境界（エッジ）に位置するように、試料１０４を遮蔽板１０５と試料台１０２との間に挟み込む。試料加工条件には、このように設置した試料１０４の遮蔽板１０５から突出した領域がミリング加工されるのに要する試料加工時間を設定する。 S11: Set sample processing conditions of the ion milling apparatus 100 (acceleration voltage of the ion source 101, discharge voltage, supply amount of argon gas, etc.). If this processing is a pretreatment for observing the cross section of the sample 104 using a scanning electron microscope or a transmission electron microscope, the cross section that will be the observation surface should be located at the boundary (edge) between the shielding plate 105 and the sample 104. Next, the sample 104 is sandwiched between the shielding plate 105 and the sample stage 102. As the sample processing conditions, the sample processing time required for milling the area of the sample 104 set up in this manner that protrudes from the shielding plate 105 is set.
　Ｓ１２：第１の熱電対１０９が測定した遮蔽板固定部１０６の温度を基準温度として記憶する。 S12: The temperature of the shield plate fixing portion 106 measured by the first thermocouple 109 is stored as a reference temperature.
　Ｓ１３：イオン源１０１からイオンビームを試料１０４に照射することにより、試料１０４の加工（ミリング処理）を実施する。 S13: The sample 104 is processed (milling process) by irradiating the sample 104 with an ion beam from the ion source 101.
　Ｓ１４：ミリング処理中は加工時間を監視する。 S14: Monitor the machining time during the milling process.
　Ｓ１５：ミリング処理中は第１の熱電対１０９で遮蔽板固定部１０６の温度をモニタリングする。 S15: During the milling process, the temperature of the shield plate fixing part 106 is monitored with the first thermocouple 109.
　Ｓ１６：遮蔽板固定部１０６の温度と基準温度とに差がある場合には、温度調整ユニット１０８は遮蔽板固定部１０６が基準温度になるよう温度調節を行い、加工を継続する。 S16: If there is a difference between the temperature of the shield plate fixing part 106 and the reference temperature, the temperature adjustment unit 108 adjusts the temperature so that the shield plate fixing part 106 reaches the reference temperature, and continues processing.
　Ｓ１７：設定した試料加工時間に到達したら加工を終了する。 S17: When the set sample processing time is reached, the processing ends.
　このように、イオンミリング装置１００は、遮蔽板固定部１０６の温度を測定する第１の温度計である熱電対１０９と、試料加工時間が設定される制御部１１０と、を有し、制御部１１０は、イオン源１０１からのイオンビーム照射前において、第１の温度計である熱電対１０９が測定した遮蔽板固定部１０６の温度を基準温度として記憶し、イオン源１０１からのイオンビーム照射中において、温度調整ユニット１０８により第１の温度計である熱電対１０９が測定する遮蔽板固定部１０６の温度を前記基準温度に維持する。これにより簡素な機構で、遮蔽板に対する試料の微小な突出量を制御可能なイオンミリング装置を提供することができる。 As described above, the ion milling apparatus 100 includes the thermocouple 109, which is a first thermometer that measures the temperature of the shielding plate fixing part 106, and the control part 110, in which the sample processing time is set. 110 stores the temperature of the shielding plate fixing part 106 measured by the thermocouple 109 as a first thermometer before irradiation with the ion beam from the ion source 101 as a reference temperature, and stores the temperature during the ion beam irradiation from the ion source 101. In this step, the temperature adjustment unit 108 maintains the temperature of the shield plate fixing portion 106 measured by the thermocouple 109, which is the first thermometer, at the reference temperature. This makes it possible to provide an ion milling device that can control the minute amount of protrusion of the sample relative to the shielding plate with a simple mechanism.
　図６に、イオンミリング装置の変形例を示す。図１に示したイオンミリング装置と共通する構成については、同じ符号を用いて示し、重複する説明は省略する。イオンミリング装置２００には、試料１０４の温度を確認するための第２の熱電対１１６が追加されている。第２の熱電対１１６についても熱電対以外の温度計を用いてもよい。この構成であれば、突出量の調整を遮蔽板固定部１０６及び遮蔽板１０５の熱収縮量の他、試料１０４の熱収縮量または熱膨張量も含めて計算できるため、試料の遮蔽板からの突出量をより精密に調整することが可能になる。試料１０４の材料が比較的大きな線膨張係数を有する材料である場合には有効な構成である。 FIG. 6 shows a modification of the ion milling device. Components common to those of the ion milling apparatus shown in FIG. 1 are indicated using the same reference numerals, and redundant explanation will be omitted. A second thermocouple 116 for checking the temperature of the sample 104 is added to the ion milling apparatus 200. A thermometer other than a thermocouple may also be used for the second thermocouple 116. With this configuration, the adjustment of the protrusion amount can be calculated not only by the amount of thermal contraction of the shielding plate fixing part 106 and the shielding plate 105 but also by the amount of thermal contraction or thermal expansion of the sample 104. It becomes possible to adjust the amount of protrusion more precisely. This is an effective configuration when the material of the sample 104 has a relatively large coefficient of linear expansion.
　以上、本発明者によってなされた発明を実施の形態に基づき具体的に説明したが、本発明は記述した実施の形態に限定されるものではなく、その要旨を逸脱しない範囲で種々変更可能である。例えば、遮蔽板固定部１０６の温度調整によって試料突出量を調整する実施例について説明したが、直接遮蔽板１０５の温度を調整するようにしてもよい。 Above, the invention made by the present inventor has been specifically explained based on the embodiments, but the present invention is not limited to the described embodiments, and various changes can be made without departing from the gist thereof. . For example, although an embodiment has been described in which the amount of sample protrusion is adjusted by adjusting the temperature of the shielding plate fixing part 106, the temperature of the shielding plate 105 may be adjusted directly.
　なお、本発明は上記した実施例に限定されるものではなく、様々な変形例が含まれる。例えば、上記した実施例は本発明を分かりやすくするために詳細に説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、ある実施例の構成の一部を他の実施例の構成に置き換えることが可能であり、また、ある実施例の構成に他の実施例の構成を加えることも可能である。また、各実施例の構成の一部について、他の構成の追加・削除・置換をすることが可能である。 Note that the present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above are described in detail to make the present invention easier to understand, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.
１００、２００：イオンミリング装置、１０１：イオン源、１０２：試料台、１０３：試料ステージ、１０４：試料、１０５：遮蔽板、１０６：遮蔽板固定部、１０７：伝熱ケーブル、１０８：温度調整ユニット、１０９：第１の熱電対、１１０：制御部、１１１：高圧電源、１１２：供給ガス制御部、１１３：排気機構、１１４：試料室、１１６：第２の熱電対、１１７：遮蔽板固定ねじ、２０１：第１カソード、２０２：第２カソード、２０３：アノード、２０４：永久磁石、２０５：加速電極、２０６：ガス配管。 100, 200: ion milling device, 101: ion source, 102: sample stage, 103: sample stage, 104: sample, 105: shielding plate, 106: shielding plate fixing part, 107: heat transfer cable, 108: temperature adjustment unit , 109: first thermocouple, 110: control unit, 111: high voltage power supply, 112: supply gas control unit, 113: exhaust mechanism, 114: sample chamber, 116: second thermocouple, 117: shield plate fixing screw , 201: first cathode, 202: second cathode, 203: anode, 204: permanent magnet, 205: accelerating electrode, 206: gas piping.

Claims (12)

  1. 　試料が載置される試料ステージと、
    　前記試料ステージによって支持される試料台及び遮蔽板固定部と、
    　前記遮蔽板固定部に固定される遮蔽板と、
    　前記試料に向けて非集束のイオンビームを照射するイオン源と、
    　前記遮蔽板固定部と伝熱ケーブルによって接続され、前記遮蔽板固定部の温度を調整する温度調整ユニットと、を有し、
    　前記試料は、前記遮蔽板と前記試料台との間に挟み込まれて保持され、
    　前記試料の前記遮蔽板からの突出量は、前記温度調整ユニットに設定される前記遮蔽板固定部の設定温度によって調整されるイオンミリング装置。     a sample stage on which the sample is placed;
    a sample stage and a shielding plate fixing part supported by the sample stage;
    a shielding plate fixed to the shielding plate fixing part;
    an ion source that irradiates an unfocused ion beam toward the sample;
    a temperature adjustment unit connected to the shielding plate fixing part by a heat transfer cable and adjusting the temperature of the shielding plate fixing part,
    The sample is held between the shielding plate and the sample stage,
    An ion milling apparatus in which the amount of protrusion of the sample from the shielding plate is adjusted by a set temperature of the shielding plate fixing part set in the temperature adjustment unit.
  2. 　請求項１において、
    　前記温度調整ユニットは、前記遮蔽板固定部を冷却するイオンミリング装置。     In claim 1,
    The temperature adjustment unit is an ion milling device that cools the shield plate fixing part.
  3. 　請求項１において、
    　前記温度調整ユニットは、前記遮蔽板固定部を冷却または加温するイオンミリング装置。     In claim 1,
    The temperature adjustment unit is an ion milling device that cools or heats the shield plate fixing part.
  4. 　請求項１において、
    　試料突出量が設定される制御部を有し、
    　前記制御部は、前記温度調整ユニットが前記遮蔽板固定部の温度を前記設定温度に調整した後に、前記イオン源から前記試料に向けてイオンビームを照射し、
    　前記設定温度は、前記試料の前記遮蔽板からの突出量が前記試料突出量となる温度として設定されるイオンミリング装置。     In claim 1,
    It has a control section in which the amount of sample protrusion is set,
    The control unit irradiates the sample with an ion beam from the ion source after the temperature adjustment unit adjusts the temperature of the shield plate fixing unit to the set temperature,
    The set temperature is an ion milling device in which the set temperature is set as a temperature at which the amount of protrusion of the sample from the shielding plate becomes the amount of sample protrusion.
  5. 　請求項４において、
    　前記制御部は、前記遮蔽板から突出した前記試料の部分が削られた後に前記イオン源からのイオンビームの照射を停止し、前記試料の前記遮蔽板からの突出量が再度、前記試料突出量となる設定温度を再設定し、前記温度調整ユニットが前記遮蔽板固定部の温度を前記再設定された設定温度に調整した後に、前記イオン源からのイオンビームの照射を再開するイオンミリング装置。     In claim 4,
    The control unit stops irradiation of the ion beam from the ion source after the portion of the sample protruding from the shielding plate is scraped, and the control unit causes the amount of protrusion of the sample from the shielding plate to become the amount of protrusion of the sample again. An ion milling apparatus that resets a set temperature, and restarts irradiation with an ion beam from the ion source after the temperature adjustment unit adjusts the temperature of the shielding plate fixing part to the reset set temperature.
  6. 　請求項４において、
    　前記遮蔽板固定部の温度を測定する第１の温度計を有し、
    　前記制御部は、前記第１の温度計により測定された前記遮蔽板固定部の温度が前記設定温度の許容範囲を外れている場合には、前記イオン源からのイオンビームの照射を停止して、前記温度調整ユニットにより前記遮蔽板固定部の温度を前記設定温度に調整するイオンミリング装置。     In claim 4,
    a first thermometer that measures the temperature of the shielding plate fixing part;
    The control unit is configured to stop irradiation of the ion beam from the ion source when the temperature of the shielding plate fixing unit measured by the first thermometer is outside an allowable range of the set temperature. , an ion milling apparatus in which the temperature of the shield plate fixing part is adjusted to the set temperature by the temperature adjustment unit.
  7. 　請求項１において、
    　前記遮蔽板固定部の温度を測定する第１の温度計と、
    　試料加工時間が設定される制御部と、を有し、
    　前記制御部は、前記イオン源からのイオンビーム照射前において、前記第１の温度計が測定した前記遮蔽板固定部の温度を基準温度として記憶し、前記イオン源からのイオンビーム照射中において、前記温度調整ユニットにより前記第１の温度計が測定する前記遮蔽板固定部の温度を前記基準温度に維持するイオンミリング装置。     In claim 1,
    a first thermometer that measures the temperature of the shield plate fixing part;
    a control unit in which sample processing time is set;
    The control unit stores the temperature of the shield plate fixing part measured by the first thermometer as a reference temperature before irradiation with the ion beam from the ion source, and during the ion beam irradiation from the ion source, An ion milling apparatus in which the temperature of the shielding plate fixing part, which is measured by the first thermometer, is maintained at the reference temperature by the temperature adjustment unit.
  8. 　請求項１において、
    　前記試料の温度を測定する第２の温度計を有するイオンミリング装置。     In claim 1,
    An ion milling device including a second thermometer that measures the temperature of the sample.
  9. 　イオンミリング装置を用いた試料加工方法であって、
    　前記イオンミリング装置は、試料が載置される試料ステージと、前記試料ステージによって支持される試料台及び遮蔽板固定部と、前記遮蔽板固定部に固定される遮蔽板と、前記試料に向けて非集束のイオンビームを照射するイオン源と、前記遮蔽板固定部と伝熱ケーブルによって接続され、前記遮蔽板固定部の温度を調整する温度調整ユニットと、試料突出量が設定される制御部とを備え、
    　前記温度調整ユニットは、前記遮蔽板固定部の温度を設定温度に調整し、
    　前記イオン源は、前記遮蔽板と前記試料台との間に挟み込まれて保持された前記試料に向けてイオンビームを照射し、
    　前記設定温度は、前記試料の前記遮蔽板からの突出量が前記試料突出量となる温度として設定される試料加工方法。     A sample processing method using an ion milling device, the method comprising:
    The ion milling apparatus includes a sample stage on which a sample is placed, a sample stage and a shielding plate fixing part supported by the sample stage, a shielding plate fixed to the shielding plate fixing part, and a shielding plate fixed to the shielding plate fixing part. an ion source that irradiates an unfocused ion beam; a temperature adjustment unit that is connected to the shielding plate fixing part by a heat transfer cable and adjusting the temperature of the shielding plate fixing part; and a control part that sets a sample protrusion amount. Equipped with
    The temperature adjustment unit adjusts the temperature of the shield plate fixing part to a set temperature,
    The ion source irradiates an ion beam toward the sample held between the shielding plate and the sample stage,
    The sample processing method wherein the set temperature is set as a temperature at which the amount of protrusion of the sample from the shielding plate becomes the amount of protrusion of the sample.
  10. 　請求項９において、
    　前記イオン源は、前記遮蔽板からの突出した前記試料の部分が削られた後にイオンビームの照射を停止し、
    　前記制御部は、前記試料の前記遮蔽板からの突出量が再度、前記試料突出量となる設定温度を再設定し、
    　前記温度調整ユニットは、前記遮蔽板固定部の温度を前記再設定された設定温度に調整し、
    　前記イオン源は、イオンビームの照射を再開する試料加工方法。     In claim 9,
    The ion source stops irradiation with the ion beam after the portion of the sample protruding from the shielding plate is scraped;
    The control unit resets a set temperature at which the amount of protrusion of the sample from the shielding plate becomes the amount of protrusion of the sample again,
    The temperature adjustment unit adjusts the temperature of the shielding plate fixing part to the reset temperature,
    In the sample processing method, the ion source restarts ion beam irradiation.
  11. 　請求項９において、
    　前記イオンミリング装置は、前記遮蔽板固定部の温度を測定する温度計を備え、
    　前記イオン源は、前記温度計により測定された前記遮蔽板固定部の温度が前記設定温度の許容範囲を外れている場合にはイオンビームの照射を停止し、
    　前記温度調整ユニットは、前記遮蔽板固定部の温度を前記設定温度に調整する試料加工方法。     In claim 9,
    The ion milling device includes a thermometer that measures the temperature of the shield plate fixing part,
    The ion source stops irradiation of the ion beam when the temperature of the shield plate fixing part measured by the thermometer is outside the allowable range of the set temperature,
    In the sample processing method, the temperature adjustment unit adjusts the temperature of the shielding plate fixing part to the set temperature.
  12. 　イオンミリング装置を用いた試料加工方法であって、
    　前記イオンミリング装置は、試料が載置される試料ステージと、前記試料ステージによって支持される試料台及び遮蔽板固定部と、前記遮蔽板固定部に固定される遮蔽板と、前記試料に向けて非集束のイオンビームを照射するイオン源と、前記遮蔽板固定部と伝熱ケーブルによって接続され、前記遮蔽板固定部の温度を調整する温度調整ユニットと、前記遮蔽板固定部の温度を測定する温度計と、試料加工時間が設定される制御部とを備え、
    　前記制御部は、前記イオン源からのイオンビーム照射前において、前記温度計が測定した前記遮蔽板固定部の温度を基準温度として記憶し、
    　前記イオン源は、前記遮蔽板と前記試料台との間に挟み込まれて保持された前記試料に向けてイオンビームを照射し、
    　前記温度調整ユニットは、前記イオン源からのイオンビーム照射中において、前記温度計が測定する前記遮蔽板固定部の温度を前記基準温度に維持する試料加工方法。     A sample processing method using an ion milling device, the method comprising:
    The ion milling apparatus includes a sample stage on which a sample is placed, a sample stage and a shielding plate fixing part supported by the sample stage, a shielding plate fixed to the shielding plate fixing part, and a shielding plate fixed to the shielding plate fixing part. an ion source that irradiates an unfocused ion beam, a temperature adjustment unit that is connected to the shielding plate fixing part by a heat transfer cable and adjusting the temperature of the shielding plate fixing part, and measuring the temperature of the shielding plate fixing part. Equipped with a thermometer and a control unit where sample processing time is set,
    The control unit stores the temperature of the shield plate fixing part measured by the thermometer as a reference temperature before irradiation with the ion beam from the ion source,
    The ion source irradiates an ion beam toward the sample held between the shielding plate and the sample stage,
    In the sample processing method, the temperature adjustment unit maintains the temperature of the shield plate fixing part measured by the thermometer at the reference temperature during ion beam irradiation from the ion source.
PCT/JP2022/033810 2022-09-08 2022-09-08 Ion milling device and method for processing specimen WO2024053074A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010169459A (en) * 2009-01-21 2010-08-05 Jeol Ltd Sample processing device
JP2010257856A (en) * 2009-04-28 2010-11-11 Hitachi High-Technologies Corp Processing device and sample processing method
JP2012154846A (en) * 2011-01-27 2012-08-16 Jeol Ltd Sample preparation apparatus
WO2014199737A1 (en) * 2013-06-10 2014-12-18 株式会社 日立ハイテクノロジーズ Ion milling device
JP2016095895A (en) * 2013-01-30 2016-05-26 株式会社日立ハイテクノロジーズ Sample processing method using ion milling apparatus and ion milling apparatus
JP2016173874A (en) * 2013-06-24 2016-09-29 株式会社日立ハイテクノロジーズ Ion milling device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010169459A (en) * 2009-01-21 2010-08-05 Jeol Ltd Sample processing device
JP2010257856A (en) * 2009-04-28 2010-11-11 Hitachi High-Technologies Corp Processing device and sample processing method
JP2012154846A (en) * 2011-01-27 2012-08-16 Jeol Ltd Sample preparation apparatus
JP2016095895A (en) * 2013-01-30 2016-05-26 株式会社日立ハイテクノロジーズ Sample processing method using ion milling apparatus and ion milling apparatus
WO2014199737A1 (en) * 2013-06-10 2014-12-18 株式会社 日立ハイテクノロジーズ Ion milling device
JP2016173874A (en) * 2013-06-24 2016-09-29 株式会社日立ハイテクノロジーズ Ion milling device

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