JP2008130390A - Charged beam device and its cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charged beam device, and its cleaning method, capable of efficiently removing stains by reactive gas. <P>SOLUTION: On a sample holder 3 with a sample 4 loaded and appropriately movable, a gas supply part insertion hole 17 for inserting a gas gun 11 supplying reactive gas 18 to a charged beam irradiated part on the sample 4, and a cleaning room 8 having a charged beam guide port 16 for guiding in charged beams 6 are provided to remove extraneous matters 14 affixed to a gas nozzle 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a charged beam apparatus that performs observation / analysis or processing of a sample by irradiating a charged beam, and a cleaning method thereof.

  In a charged beam apparatus that irradiates a charged beam (ion beam, electron beam) and observes / analyzes or processes a sample, when the charged beam is irradiated while supplying a reactive gas to the sample surface, the sample is deposited. (Beam-induced deposition) and etching can be locally accelerated. The former method is called gas assisted deposition (hereinafter abbreviated as GAD), and semiconductor wiring connection in a semiconductor integrated circuit (LSI) or the like, or focused ion beam (hereinafter referred to as “focused ion beam”). Processing of sample cross-section by FIB), formation of surface protection film to reduce damage to the sample when preparing a transmission electron microscope (hereinafter abbreviated as TEM), or marking of defective parts, etc. Has been used. On the other hand, the latter method is called Gas Assisted Etching (hereinafter abbreviated as GAE). In addition to high-speed removal of semiconductor wiring such as LSI, a good scanning electron microscope (hereinafter referred to as “Scanning Electron Microscope”) , Abbreviated as SEM), which is used to make the step of the processed surface remarkable by FIB in order to obtain an image.

  By the way, when the above gas processing such as GAD and GAE is performed, the reactive gas used reacts in the charged beam device, and dirt mainly composed of gas components adheres to the device or sample in the lens in the form of a film. There is a case. The dirt film increases in thickness when the gas treatment is repeated, and may be peeled off by impact or the like to become a foreign substance. In addition, when this film is an insulator, it is charged and causes beam drift, which may cause problems when forming a deposition film. Therefore, it is necessary to periodically remove the dirt film in order to avoid these problems.

  As a method for cleaning dirt caused by the reactive gas, there is a method of removing dirt by etching by irradiating a charged object with a charged beam while keeping the sample chamber of the charged beam apparatus in a reactive gas atmosphere (Patent Document 1, etc.). reference).

JP 63-313458 A

  However, in the above method, since the reactive gas is supplied to the entire sample chamber, the amount of gas molecules adsorbed on the object to be cleaned is reduced, and it is difficult to perform the cleaning process efficiently. Therefore, it takes time to complete the cleaning, and the throughput of the apparatus may be reduced.

  An object of the present invention is to provide a charged beam apparatus capable of efficiently removing dirt caused by a reactive gas, and a cleaning method therefor.

  In order to achieve the above object, the present invention provides a charged beam generation source for generating a charged beam, a charged beam optical system for focusing the charged beam from the charged beam generation source and irradiating the sample, and a charged beam on the sample. A gas supply unit that supplies a reactive gas to the irradiated portion, a gas supply unit insertion port for inserting the gas supply unit, and a charged beam introduction port for introducing a charged beam are provided in the sample chamber. And a cleaning chamber.

  According to the present invention, it is possible to increase the number of reactive gas molecules adsorbed on the object to be cleaned, so that contamination due to the reactive gas can be efficiently removed.

  Embodiments of a charged beam apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of a charged beam apparatus according to a first embodiment of the present invention.

  The charged beam apparatus shown in the figure has a sample chamber 1 in which the chamber is evacuated, a movable stage 2 provided in the sample chamber 1, and a sample 4 mounted on the stage 2 and fixed thereon. The sample holder 3 fixed by means (for example, a pin), a charged beam mirror 10 for irradiating a charged beam (electron beam, ion beam) 6 toward the sample 4, and a charged beam irradiation portion on the sample 4 are reactive. A gas gun (gas supply unit) 11 for supplying gas, a cleaning chamber 8 for removing dirt due to reactive gas adhering to the gas gun 11, and an end point of the cleaning process for the gas gun 11 (object to be cleaned) are detected. An irradiation energy dispersive X-ray analyzer (hereinafter abbreviated as EDX) 35 (see FIG. 9 described later) and a secondary electron detector (electron detection means) 1 for detecting secondary electrons from the sample 4 It is equipped with a.

The sample chamber 1 is connected to an exhaust system (not shown) composed of a turbo molecular pump, a dry pump, a valve, and the like, and has a high degree of vacuum of, for example, about 10 ⁻⁵ Pa without flowing reactive gas. Is held in. Although not particularly illustrated, the sample chamber 1 is adjacent to a load lock chamber so as to be interposed between an air transport unit (not shown) for transporting the sample in the air. When the sample 4 is carried in, for example, the sample 4 is transferred from the FOUP (Front Opening Unified Pod) or the like onto the stage 2 waiting in the load lock chamber by an atmospheric transfer robot (not shown) in the atmospheric transfer unit and loaded. After the atmosphere in the lock chamber is exhausted, the stage 2 moves into the sample chamber 1. In addition, what is necessary is just to carry out in the reverse procedure to the above when carrying out the sample 4.

  The stage 2 is a five-axis stage that rotates (R) and tilts (T) in addition to movement in three directions of X, Y, and Z, and appropriately moves the sample holder 3 on which the sample 4 is placed according to work. For the sake of explanation, the sample 4 is, for example, a silicon wafer having a diameter of 300 mm.

  FIG. 2 is a top view of the sample holder 3 in the charged beam apparatus according to the first embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same part as the previous figure, and description is abbreviate | omitted (the following figure is also the same).

  As shown in the drawing, on the upper surface of the sample holder 3, in addition to the sample 4, a charged beam adjusting jig 7 provided with a pattern for correcting focus and astigmatism of the charged beam 6, and a gas gun 11 A cleaning chamber 8 for removing attached dirt and a cartridge mechanism portion 75 (see FIG. 24 described later) for holding a microsample extracted from the sample 4 are provided.

  FIG. 3 is a cross-sectional view of the cleaning chamber 8. 3A is a cross-sectional view taken along the line IIIa-IIIa in FIG. 2, and FIG. 3B is a cross-sectional view of another example.

  In FIG. 3A, the cleaning chamber 8 has a charged beam introduction port 16 which is an opening for introducing the charged beam 6 into the chamber, and an opening for inserting a gas nozzle 12 (described later) of the gas gun 11. A certain gas supply section insertion port 17 is provided. Portions other than these openings 16 and 17 are hermetically sealed so that the pressure in the room is maintained as much as possible.

  The gas gun 11 has a gas nozzle 12 through which reactive gas is ejected from an ejection hole 101 (see FIG. 5 to be described later) provided at the tip, and the gas nozzle 12 is connected to a cleaning chamber through a gas supply unit insertion port 17. 8 is inserted. A dirt film (adhesion film) 14 due to a reactive gas is attached to the gas nozzle 12. The adhesion film 14 is formed by reacting the reactive gas used in the gas treatment such as GAD or GAE in the charged beam apparatus, and is a dirt film mainly composed of components of the reactive gas.

  The diameters of the openings 16 and 17 are preferably made as small as possible. This is because the difference between the pressure of the reactive gas ejected from the ejection hole 101 of the gas nozzle 12 and the pressure on the cleaning chamber 8 side of the gas supply portion insertion port 17 is reduced, thereby reducing the reactive gas in the cleaning chamber 8. This is to increase the pressure value. As a result, the number of reactive gas molecules adhering to the cleaning object (the gas gun 11) increases, so that the cleaning speed can be improved. In view of this point, in the present embodiment, for example, the cleaning chamber 8 has a substantially cubic shape with one side of about 10 mm, and the diameters of the openings 16 and 17 are about 2 mm.

  In the cleaning chamber 8, as shown in FIG. 3B, the electrode 20 provided on the inner wall surface (upper surface) on the secondary electron detector 13 side and the other inner wall surface (side surface) are provided. It is preferable to provide the electrode 24.

  Each of the illustrated electrodes 20 and 24 is attached to the wall surface via an insulator 22 (for example, a fluororesin or the like), and is floating in potential. Each electrode 20, 24 is connected to a power source 21, and as shown in the figure, a positive potential is applied to the electrode 20 on the secondary electron detector 13 side, and the electrode 24 on the side surface is supplied with the power source 21. Is given a negative potential. As a result, more secondary electrons 23 are drawn from the cleaning chamber 8 to the detector 13 side, so that a secondary electron image having a high SN ratio can be obtained. The potential applied to the electrode 24 provided on the side surface may be a ground potential. Further, for example, if the acceleration voltage of the charged beam 6 is 1 kV, the energy of the generated secondary electrons 23 is relatively low, about 2 eV on average, so that each electrode 20, 24 has a negative or positive value of about several tens of volts. What is necessary is just to give an electric potential.

  The electrode 20 is preferably formed in a mesh shape so that the secondary electrons 23 are easily introduced into the secondary electron detector 13. In this case, if the area ratio between the portion to be meshed and the entire top surface and the mesh interval are too large, the reactive gas is likely to leak from the cleaning chamber 8, so that these sizes are sufficiently considered.

  Next, the configuration of the charged beam mirror 10 will be described with an example in which the charged beam generation source is an electron source.

  FIG. 4 is a diagram showing the internal structure of the charged beam mirror body 10 having an electron source.

  The charged beam apparatus shown in the figure includes a control unit 150 that controls each device provided in the mirror body (column) 10 (only an objective lens 156 (described later) is shown), a result of processing by the control unit 150, and the like. A display unit (monitor) 180 for displaying the electron beam, an electron source (charged beam generation source) 151 for generating an electron beam, an extraction electrode 152 for extracting an electron beam (charged beam) 6 having a predetermined emission current from the electron source 151, A first focusing coil 153 that focuses the extracted electron beam 6, a diaphragm 154 that extracts only a necessary portion of the electron beam 6 focused by the first focusing coil 153, and the electron beam 6 focused by the diaphragm 154 are focused. A second focusing coil 155 and an electron lens that focuses the electron beam 6 focused by the second focusing coil 155 and irradiates the sample 4 as a minute spot are formed. An objective lens 156 to the deflection coil 157 for scanning the electron beam 6 on the sample 4 mainly comprises.

  Among the above, the extraction electrode 152, the first focusing coil 153, the stop 154, the second focusing coil 155, the objective lens 156, the deflection coil 157, and the like focus and deflect the electron beam 6 from the electron source 151 on the sample 4. An electron beam optical system (charged beam optical system) 165 for appropriately irradiating the light beam is configured.

  The objective lens 156 includes an objective lens coil 158 that generates a magnetic field by a voltage applied to the objective lens coil voltage control power source 175, and an electrode (lower pole) 159 on the sample 4 side that includes the objective lens coil 158. The objective lens magnetic path 160 to be configured and the booster electrode (upper pole) 162 attached to the objective lens magnetic path 160 via the insulating portion 161 so as to be positioned above the lower pole 159 are provided so as to face the sample 4. Are provided at the lower end of the mirror body 10.

  Although not shown, the control unit 1 includes a processing unit (microprocessor and the like) that performs various processing operations, a storage unit (HDD, ROM, RAM, and the like) that stores processing programs and processing results, and a processing unit. An input unit (such as a keyboard) for inputting commands is provided.

  The control unit 1 is also connected to a high voltage control power source 170 connected to the electron source 151 and the extraction electrode 152, a first focusing coil control power source 171 connected to the first focusing coil 153, and a second focusing coil 155. Second focusing coil control power source 172, deflection coil control power source 173 connected to deflection coil 157, booster electrode voltage control power source 174 connected to booster electrode 162, objective lens coil voltage control power source 175 connected to objective lens coil 158 A secondary electron detector control power source 176 (see FIG. 1) connected to the secondary electron detector 13 and a gas gun controller 177 (see FIG. 1) connected to the gas gun 11 are connected. Each power source, controller, and the like are appropriately controlled using a processing unit or the like.

  FIG. 5 is an enlarged sectional view showing the vicinity of the gas gun 11 in FIG.

  In this figure, a gas gun 11 includes a gas nozzle 12 provided at its tip with an ejection hole 101 for ejecting reactive gas, a main body 102 connected to the gas nozzle 12, and a main body 102 outside a charged beam apparatus that is at atmospheric pressure. The body cover 103 that covers from the outer periphery, the vacuum bellows 104 that covers the body 102 from the outer periphery inside the sample chamber 1 held in vacuum, and the hole 105 provided in the partition wall 125 of the sample chamber 1 hold the gas gun 11. And a gas pipe 108 connected to a gas cylinder (gas source) 107 for supplying a reactive gas to the gas nozzle 12. Each member constituting the gas gun 11 is preferably made of a non-magnetic material (for example, SUS material or aluminum material) in consideration of preventing the magnetic field distribution in the mirror body 10 from being disturbed as much as possible.

  The main body 102 is connected to an air cylinder (drive device) 46 via a joint member 109 at an end opposite to the gas nozzle 12 side, and a main body cover is provided via a plurality of roller bearings 111 arranged along the outer peripheral surface. 103.

  The air cylinder 46 is connected to an air supply source (not shown), and advances and retracts the ejection hole 101 along the axial direction with respect to the sample 4 according to a command from a gas gun controller 177 (see FIG. 1). By using this advance / retreat function, when performing GAD and GAE, the ejection hole 101 can be brought close to the charged beam irradiation part on the sample 4 (for example, the position above the irradiation part, approximately 200 μm), and others In this case, the sample 4 can be saved. The gas gun 11 is provided with a stopper (not shown) for preventing the gas nozzle 12 from approaching the sample 4 for a certain distance or more to prevent the sample or the nozzle tip from being damaged by an erroneous operation or the like. Yes. The roller bearing 111 suppresses the occurrence of shaft shake when the main body 102 moves back and forth. The fine adjustment of the advance / retreat of the gas nozzle 12 is performed by a fine adjustment mechanism (not shown).

  When changing the posture of the gas gun 11 (elevation angle, depression angle, and swing angle), an adjustment screw 120 provided on the flange 106 and holding the posture of the cover main body 103 is used. Two adjustment screws 120 are attached from the vertical direction and horizontal direction of the cover main body 103 via the flange 106, and the gas gun 11 is moved in a desired posture by appropriately advancing and retracting these four screws with respect to the screw holes. Hold on. The main body 102 is connected to a rotary drive device 121 such as a motor via a power transmission device 122 such as a gear. When the gas nozzle 12 is rotated around its axis, the main body 102 is rotated via a gas gun controller 177. It can be rotated by driving the driving device 121. The movement and rotation of the gas gun 11 in the sample chamber 1 are not limited to the above-described configuration, and a robot arm controlled by the control unit 150 is provided, and the gas gun 11 is attached to the free end side of the gas gun 11 to move and rotate as appropriate. Of course, it may be moved.

  The vacuum bellows 104 is formed in an accordion shape so that it can expand and contract as the main body 102 advances and retreats, and the inside (the main body 102 side) is maintained at atmospheric pressure. Further, an O-ring 123 is provided between the flange 106 and the partition wall 125 so as to surround the hole 105, and the inside of the sample chamber 1 is separated from the atmosphere.

  The gas pipe 108 is connected to a plurality of gas cylinders 107 and a regulating valve 124 on the upstream side, and is connected to the gas nozzle 12 after being arranged in a coil shape so as to surround the vacuum bellows 104 from the outer periphery on the downstream side. . As described above, by arranging the gas pipe 108 in a coil shape, even if the main body 102 moves back and forth, it can be expanded and contracted.

Each gas cylinder 107 appropriately stores GAD deposition gas and GAE etching gas, and the reaction gas to be used can be switched according to the work contents by opening and closing the adjustment valve 124. Examples of deposition gases include tungsten carbonyl (W (CO) ₆ ), tetraethyloxysilane that produces a silicon oxide film (Si (OC ₂ H ₅ ) ₄ , also known as theos), molybdenum carbonyl (M (CO) ₆ ), Carbon-based gas, and the like. Examples of the etching gas include xenon difluoride (XeF ₂ ), fluorine-based gas (CF _4, etc.), chlorine-based gas, and the like.

  The EDX (cleaning end point detection means) 35 detects characteristic X-rays emitted from the irradiation point of the charged beam 6 accelerated to a relatively high voltage (for example, 30 kV), and performs elemental analysis at the irradiation point. The result of elemental analysis is displayed on the display unit 180 in a graph as shown in FIG. 10 to be described later (details will be described later). As a result of such elemental analysis, if it is detected that no dirt film due to reactive gas remains, cleaning is completed. In order to improve the detection accuracy of the end point of the cleaning process, it is preferable to perform the elemental analysis at a plurality of locations by irradiating the charged beam 6 to a plurality of locations on the cleaning target. Further, from the viewpoint of simplifying the configuration of the apparatus, the charged beam 6 used for emitting characteristic X-rays is preferably emitted from a charged beam generation source in the charged beam mirror body 10.

  The secondary electron detector 13 detects secondary electrons emitted from the sample 4 irradiated with the charged beam 6. Secondary electrons emitted from the sample 4 are attracted to an electric field of a scintillator (not shown) applied to a positive potential (about 10 kV) in the secondary electron detector 13 and accelerated to light the scintillator. The emitted light enters a photomultiplier tube (both not shown) by a light guide and is converted into an electric signal. The output of the photomultiplier tube is further amplified to change the luminance of the cathode ray tube of the display unit 180. Then, by synchronizing this with a scanning signal of a deflection coil (not shown) in the mirror body 10, a secondary electron image at the processing point is generated.

  As an electron detection means other than the secondary electron detector 13, there is a reflected electron detector (not shown). The backscattered electron detector detects backscattered electrons emitted from the surface of the sample 4 by irradiation of the charged beam 6, and forms a backscattered electron image as well as a secondary electron image by the secondary electron detector 13. Used for The reflected electron image can detect irregularities on the sample observation surface.

  Although not particularly shown, the sample chamber 1 is provided with an optical microscope and a Z sensor. The optical microscope checks several alignment marks on the sample 4 and aligns the sample 4. The Z sensor measures the distance to the processing point on the sample 4 and moves the stage 2 in the vertical direction (Z-axis direction) so as to cancel the amount of change even if the height of the surface of the sample 4 changes due to warpage or the like. To keep the working distance constant. As a result, occurrence of focus deviation of the charged beam due to wafer warpage or the like is prevented.

  FIG. 6 is a diagram showing an example of a graphical user interface (hereinafter abbreviated as GUI) of the charged beam device displayed on the display unit 180.

  The GUI screen 37 shown in the figure includes a message display unit 38 for displaying a notification message for the cleaning time, an image display unit 39 for displaying a secondary electron image of the sample, the current value of the charged beam 6, and the beam type. A parameter display unit 40 for displaying beam parameters such as beam adjustment display, and an operation mode selection panel (navigation panel) 41 for selecting an operation mode to be executed from a plurality of types of predetermined operation modes, A command panel 42 on which commands for operating the charged beam device are displayed according to the operation mode selected on the operation mode selection panel 41 is provided.

  The command panel 42 is provided with a cleaning button 43 for starting the cleaning of the gas gun 11. If the maintenance button 43 is selected when a maintenance request is issued on the message display unit 38, the cleaning process of the gas gun 11 is automatically started. In addition to this, the command panel 42 displays various commands for performing operations such as high voltage application and beam current measurement, and the operator can select a desired operation.

  The operation mode selection panel 41 includes, for example, a mode in which a general operator performs processing based on a preset recipe (job mode), and each set value for operation (beam focus, astigmatism correction, etc.) Mode (system mode) for manually changing the value of ()), mode (maintenance mode) for displaying data (cumulative usage time and usable time of each device, etc.) used when performing maintenance of the device, etc. There is a button that can be selected.

  In the GUI screen 37 configured as described above, the cleaning time notification message is displayed on the message display unit 38 by the control unit 150 as follows.

  The control unit 150 irradiates the charged beam from the charged beam generation source (for example, charged beam acceleration voltage, current amount, current density, etc.) and the ejection condition of the reactive gas from the gas gun 11 (for example, reactive gas The amount of dirt (attached film 14) adhering to the gas gun 11 is predicted and calculated based on the irradiation amount, the type of reactive gas, the accumulated amount of the gas nozzle 12 position change, and the like. The predicted calculation value obtained in this way is compared with a preset “threshold value”, and a signal for displaying a notification message of the cleaning timing when the predicted calculation value reaches or exceeds the threshold value is displayed on the display unit 180. Output to. The display unit 180 to which this signal is input displays a predetermined message (for example, “Please perform maintenance of the gas nozzle” shown in FIG. 6) on the message display unit 38 to notify the operator of the cleaning time. In this embodiment, the display unit 180 is used as a notification means for notifying the cleaning time. However, a separate warning lamp may be provided in the charged beam device, and this may be turned on when necessary.

  When the notification message of the cleaning time is displayed on the message display unit 38, the operator selects the cleaning button 43 and starts cleaning the gas gun 11.

  FIG. 7 is a diagram showing how the gas gun 11 is cleaned in the charged beam apparatus according to the first embodiment of the present invention.

  Here, a case where an electron beam is used as the charged beam 6 will be described first.

  In the charged beam apparatus configured as described above, as illustrated, an electron beam (charged beam) 6 from an electron source 151 (charged beam generation source) is passed through an electron beam optical system 165 (charged beam optical system). The charged beam 6 focused and focused by the electron beam optical system 165 is introduced into the cleaning chamber 8 through the charged beam introduction hole 16, and the gas nozzle 12 of the gas gun 11 is introduced through the gas supply portion insertion port 17. Insert into the cleaning chamber 8. In this state, when an etching gas (for example, xenon difluoride) 18 is ejected as a reactive gas from the ejection hole 101, the gas pressure of the etching gas 18 on the surface of the nozzle 12 is increased as compared with the case where there is no cleaning chamber 8. As a result, the amount of molecules of the reactive gas 18 attached (adsorbed) to the gas nozzle 12 increases. The etching gas 18 whose adhesion amount to the gas nozzle 12 is increased in this way reacts with the adhesion film 14 to remove dirt, and is activated by the charged beam 6 introduced through the charged beam introduction hole 16. Since the reaction with the adhesion film 14 is promoted by being radicalized, dirt can be efficiently removed as compared with the case without the cleaning chamber 8.

  Next, a case where an ion beam is used as the charged beam 6 will be described. When an ion beam is used, an ion beam can be generated by using a liquid metal ion source such as gallium as a charged beam generation source. Other ion beam sources include, for example, group IV liquid metal ion sources such as silicon and germanium that generate non-contaminating ion beams, gas phase field ion sources such as helium and argon, and gas plasmas such as oxygen and argon. There are ion sources.

  When an ion beam is used instead of the electron beam described above, cleaning using sputtering can be performed by directly irradiating the deposition film 14 with the ion beam.

  In order to directly irradiate the deposition film 14 with the ion beam, first, a secondary electron image (for example, a SIM image) is obtained by observing the gas nozzle 12 at a low resolution, and an approximate location of the deposition film 14 is specified. High-resolution observation is performed using the secondary electron image thus obtained, and a specific position of the adhesion film 14, that is, an ion beam irradiation location is specified. At this time, as shown in FIG. 3B, a potential is applied to the cleaning chamber 8 so that the secondary electrons are easily emitted to the outside, so that a secondary electron image can be easily obtained. .

  When the etching gas 18 is jetted into the cleaning chamber 8 while directly irradiating the ion beam 6 to the irradiation site specified in this way, the etching action is promoted, compared with the case where the adhesion film 14 is removed only by sputtering. High-speed etching. For example, when xenon difluoride is used as the reactive gas 18 to remove the adhesion film 14 such as silicon or silicon oxide, although it depends on conditions, the sputtering rate is about 2 compared with the sputtering rate using only a gallium ion beam. It is possible to increase the etching rate by about 3 times.

  Further, in the cleaning method using only sputtering, when the object to be cleaned contains metal, sputtered material scatters around and causes metal contamination. However, since the sputtering is performed in the cleaning chamber 8 in the present embodiment, it is possible to suppress the spatter that becomes the metal contamination from being scattered to the surroundings, and to protect the devices in the charged beam apparatus from the metal contamination. Can do. Further, when an etching gas is used, the metal (sputtered material) reacts with the gas to become a gas compound, so that it can be exhausted in a vaporized state. As a result, a substance that is a source of metal contamination can be removed from the cleaning chamber 8, so that the risk of metal sputtered material coming out of the cleaning chamber 8 due to some action can be reduced.

  By the way, in each of the above cases, when it is difficult to remove the contamination of the gas nozzle 12 only by the scanning of the charged beam 6, the gas nozzle 12 is moved in the axial direction (in FIG. 7) using the air cylinder 46 provided in the gas gun 11. The portion irradiated with the charged beam 6 may be appropriately changed and adjusted by advancing and retreating in the A direction) or rotating around the axis (B direction in FIG. 7) using the rotary drive device 121. Thereby, the outer peripheral surface of the gas nozzle 12 can be uniformly cleaned.

  FIG. 8 is a diagram showing another aspect of cleaning the gas gun 11 in the charged beam apparatus according to the first embodiment of the present invention.

  In this figure, unlike the case of FIG. 7, the gas nozzle 12 is arranged in the cleaning chamber 8 away from the irradiation position of the charged beam 6. When the gas nozzle 12 is arranged in this way and the charged beam 6 is introduced into the cleaning chamber 8 without directly irradiating the deposited film 14, the charged beam 6 is deposited on the deposited film 14 in order to synergize the sputtering action as shown in FIG. Compared with the case of direct irradiation, soft and highly uniform etching with a reduced etching rate can be achieved. This method is not limited to the type of charged beam generation source (electron source, ion source, etc.).

  Next, a method for detecting the end point of the cleaning process using the EDX 35 will be described with reference to the drawings.

  FIG. 9 is a diagram showing how the end point of the cleaning process is detected using EDX. FIG. 9A is a diagram showing how characteristic X-rays are detected by EDX, and FIG. 9B is a diagram of the gas nozzle 12 as viewed from above.

  In FIG. 9A, a characteristic X-ray 36 is emitted from the charged beam 6 irradiated portion of the gas nozzle 12, and this characteristic X-ray 36 is detected by the EDX 35 provided above the irradiated portion. Further, as shown in FIG. 9B, a plurality of inspection points 34 are set on the gas nozzle 12 in order to improve the analysis accuracy.

  When the cleaning end point is detected, an electron beam 6 accelerated to a high voltage (for example, about 30 kV) is irradiated to a plurality of inspection points 34 set on the gas nozzle 12. At this time, characteristic X-rays 36 are emitted from each inspection point 34 by the electron beam 6, and the characteristic X-rays 36 are detected by the EDX 35 and elemental analysis is performed at each inspection point 34.

  10 and 11 are diagrams showing examples of analysis results of elemental analysis by EDX.

  FIG. 10 shows the results of elemental analysis when tungsten (W) adheres to the surface of the gas nozzle 12 made of SUS (mainly iron, nickel, and chromium) when tungsten carbonyl is used as the reactive gas 18. FIG. 10A shows an analysis result before removing tungsten, and FIG. 10B shows an analysis result after removing tungsten.

  The analysis result shown in FIG. 10A has a peak portion 190 indicating tungsten, and a peak portion 191 in which SUS components such as iron, nickel, and chromium are mainly detected on the lower energy side. have. On the other hand, from the analysis result shown in FIG. 10B, the peak portion 190 indicating tungsten disappears as indicated by the broken line L in the drawing.

  In this way, the elemental analysis before cleaning and the elemental analysis during cleaning are compared. If the element (tungsten) contained in the dirt remains, the GAE is continued in the cleaning chamber 8 and the element is removed. In that case, that time is taken as the cleaning end point.

  When elemental analysis is performed by detecting the specific X-ray 36, the gas nozzle 12 to be cleaned is preferably taken out of the cleaning chamber 8 as shown in FIG. In this way, the yield of characteristic X-rays 36 can be increased and the analysis accuracy can be improved.

  On the other hand, when depositing on the sample 4, in order to prevent heavy metals contained in the reactive gas (depot gas) 18 from contaminating the devices in the charged beam apparatus, the ion beam is not composed of gallium ion beam but argon. In some cases, an ion beam is used, the gas nozzle 12 is made of silicon, and silicon oxide is deposited using tetraethyloxysilane (SiOC2H54), which is a compound of silicon, oxygen, carbon, and hydrogen, as the deposition gas 18. In this case, silicon oxide adheres to the silicon gas nozzle 12 as dirt. This case will be described with reference to FIG.

  FIG. 11 is a diagram showing an elemental analysis result when silicon oxide adheres to the surface of the gas nozzle 12 made of silicon when tetraethyloxysilane is used as the reactive gas 18, and FIG. FIG. 11B shows the analysis result after removing the silicon oxide before removing the silicon oxide.

  The analysis result shown in FIG. 11A has a peak portion 195 indicating carbon (C) and oxygen (O), and has a peak portion 196 indicating silicon (Si) on the higher energy side. . On the other hand, from the analysis result shown in FIG. 11B, the peak portion 195 indicating carbon and oxygen disappears as indicated by the broken line M in the figure. Also in this case, as in the case of FIG. 10, the time point when the state shown in FIG. 10B in which only silicon that is the base material of the gas nozzle 12 is detected can be determined as the cleaning end point.

  Next, effects of the charged beam apparatus according to the present embodiment will be described.

  First, a problem that occurs due to contamination by reactive gas adhering to a gas nozzle or the like will be described with reference to the drawings.

  FIG. 12 is a diagram illustrating a state in which a charged beam and a reactive gas are irradiated to a sample in the charged beam apparatus.

  In this figure, the molecules of the reactive gas 218 adhering to the sample 204 are decomposed by the charged beam 206 and the secondary electrons 295 to form a deposition film 213 on the sample 204 surface. At this time, the deposition film 213 is simultaneously subjected to the sputtering action by the charged beam 206, and the difference between the sputtering amount and the deposition amount becomes the actual deposition amount.

  The gas nozzle 212 is sufficiently close to the processing point in order to increase the gas molecule density at the processing point (GAD portion) and increase the deposition rate. Sputtered particles 296 emitted from the deposition film 213, secondary electrons 295, reflected electrons, and the like are emitted from the surface of the nozzle 212. As a result, an adhesion film (deposition film) 214 is formed on the surface of the nozzle 212, and its thickness increases when GAD is repeated. At this time, when an impact or the like is applied, the adhesion film 214 is peeled off, and if it falls on the sample 204, it becomes a foreign substance.

  When the deposition film 213 and the adhesion film 214 are insulators, secondary electrons and reflected electrons accumulate on the deposition film 213 and the adhesion film 214 and are charged. When the deposition film 213 and the adhesion film 214 are charged in this way, the charged beam 206 drifts (two-dot chain line in the figure), and there may be a problem that the position of the deposition film 213 on the sample 204 drifts. The beam drift due to the adhesion film 214 becomes conspicuous when the acceleration voltage of the charged beam 206 is relatively low and when many secondary electrons and reflected electrons from the deposition film 213 are generated. This case will be described with reference to FIG.

  FIG. 13 is a diagram showing a state in which deposition is performed when an insulating deposit 214 adheres to the gas nozzle 212. In FIG. 13, time elapses in the order of (a), (b), and (c), and the charge amount of the adhesion film 214 increases with the elapse of time, and the charged beam 206 drifts to the left in the drawing. The amount is increasing. When the amount of beam drift increases in this way, the position of the deposition film 213 formed on the sample 204 also shifts to the left. If there is such misalignment of the deposition film 213, when the position of the deposition film 213 is used as a mark indicating the position of the defective portion, the deposition film 213 does not function as a mark, and the position of the defective portion is accurately determined. It becomes impossible to know. Further, there may be a problem that the height of the deposition film 213 is smaller than a desired value, or the height (step) of the deposition film 213 is low, so that it is difficult to recognize as a mark.

  As a technique for removing dirt (attached film) due to the reactive gas adhering to the gas nozzle or the like in this way, the charged object is irradiated with the charged beam while the sample chamber of the charged beam apparatus is in the reactive gas atmosphere, and the dirt is obtained by etching. There exists a thing which removes (refer patent document 1 etc.).

  However, in this method, since the reactive gas is supplied to the entire sample chamber, the amount of gas molecules adsorbed on the object to be cleaned is reduced, and it is difficult to efficiently perform the cleaning process. Therefore, it takes time to complete the cleaning, and the throughput of the apparatus may be reduced. Also, in this technique, if the amount of reactive gas supplied is increased in order to increase the amount of gas molecules adsorbed on the object to be cleaned, the pressure in the sample chamber increases, increasing the load on the exhaust system and causing equipment trouble. Will occur. Furthermore, in this case, if an etching gas is used as the reactive gas, it will damage the equipment in the apparatus, making it difficult to improve the cleaning efficiency. Furthermore, if the cleaning efficiency is inferior, the opportunity to replace the gas nozzle with a new one also increases. When exchanging the nozzle, it is necessary to perform the exchanging work after returning the sample chamber to the atmosphere, and it may take time to restart the apparatus, which may cause a problem that the throughput of the apparatus is reduced.

  On the other hand, in the charged beam apparatus of the present embodiment, the gas supply unit insertion port 17 for inserting the gas gun 11 and the charged beam introduction port 16 for introducing the charged beam 6 in the sample chamber 1. A cleaning chamber 8 is provided. Then, in this cleaning chamber 8, while introducing the charged beam 6 through the charged beam introduction hole 16, the gas nozzle 12 of the gas gun 11 is inserted through the gas supply part insertion port 17, and the reactivity from the ejection hole 101. By performing the GAE by ejecting the etching gas 18 as a gas, it is possible to increase the molecules of the reactive gas adsorbed on the gas nozzle 12 that is the object to be cleaned. Therefore, according to the present embodiment, the reactive gas molecules adsorbed on the cleaning object can be increased in this way, so that contamination due to the reactive gas can be efficiently removed.

  Further, in the present embodiment, since the cleaning process is performed in the cleaning chamber 8 as described above, even if the deposit contains a heavy metal component, the removed material can be kept indoors, and the peripheral device is contaminated with metal. Can be prevented.

  Furthermore, in the present embodiment, the control unit 150 causes dirt (attached film) to adhere to the gas gun 11 based on the irradiation conditions of the charged beam 6 from the charged beam generation source and the reactive gas ejection conditions of the gas gun 11. The amount of 14) is predicted, and the predicted time is compared with the “threshold value” to inform the operator of the cleaning time. Thereby, the operator can know the cleaning time before such trouble occurs, instead of knowing the cleaning time after the occurrence of the foreign matter or mark misalignment. Accordingly, it is possible to reduce the loss generated from the defective sample and to reduce the apparatus down time, thereby improving the throughput.

  In this embodiment, the elemental analysis of the cleaning object (gas nozzle 12) is performed by the EDX 35, and the cleaning end point is accurately detected. Thereby, since the deposit | attachment 14 can be removed completely, it can suppress that malfunctions, such as generation | occurrence | production of a foreign material and a beam drift, recur. In addition, since the end point can be accurately detected, the base material of the cleaning object is not damaged and the life of the base material can be extended.

  In the above embodiment, the case where the cleaning chamber 8 is provided on the sample holder 3 has been described. However, for example, the cleaning chamber 8 is attached to an end of an articulated arm or the like that can freely move in the sample chamber 1. For example, it may be configured as independent from the sample holder 3 or the like. Further, the shape of the cleaning chamber 8 is not limited to the case illustrated above, and may be a rectangular parallelepiped, a quadrangular pyramid, a cylinder, or the like, and the outer shape is not particularly limited. This also applies to the positions of the openings 16 and 17, and it is of course possible to provide both on the same surface. Further, in the case where a plurality of gas guns 11 are provided, the gas supply part insertion port 17 is provided with a large opening (for example, for example) so that the plurality of gas guns 11 can be introduced into the cleaning chamber 8. Oval).

  The electron beam mirror whose charged beam generation source is an electron source described above with reference to FIG. 4 may be configured as a defect observation scanning electron microscope (hereinafter abbreviated as a review SEM). The review SEM is a type of scanning electron microscope (hereinafter abbreviated as SEM), and is used for observation of defects, foreign matters, etc. at the production site of semiconductors and the like. This review SEM does not include images (defect images) that contain each defect in the field of view based on inspection results (defect coordinate data, etc.) obtained by an inspection device (such as an optical inspection device or SEM inspection device). A function for automatically acquiring a non-defective pattern image (reference image) (Automatic Defect Review: hereinafter abbreviated as ADR), and a feature amount of each defect based on the defect image and reference image acquired by this ADR A function that automatically classifies defects by comparing the feature values obtained in this way with the data (teaching data) that is the standard for defect classification set in advance (automatic defect classification) ): Hereinafter abbreviated as ADC).

  In order to perform the ADR and ADC functions with the above charged beam apparatus, for example, the storage unit of the control unit 150 stores the defect image and the reference image, the feature amount data, the teaching data, and a program used when performing each processing. The processing unit of the control unit 150 captures the defect image and the reference image based on the inspection result, calculates the feature amount based on the image, and classifies the defect based on the teaching data. It is good to do.

  Here, the main flow of typical wafer inspection work using the review SEM will be described.

  First, when performing ADR, an inspection wafer is carried into the sample chamber by a transfer means (for example, FOUP (Front Opening Unified Pod), an atmospheric transfer unit, etc.). Then, ADR is performed on the loaded wafer in low resolution observation (review mode), and ADC is performed subsequently. In this way, for example, defects are roughly classified according to the cause of occurrence of “peeling”, “foreign matter”, “scratch”, “dust”, etc., and these are further classified as “short-circuit”, “open”, “convex defect” ”,“ Concave defect ”,“ VC (voltage contrast) defect ”, and the like. When it is necessary to observe in more detail the shape of the foreign matter, the defect portion, and the like thus classified, high-resolution observation is appropriately performed. Further, when it is necessary to further investigate the cause of the occurrence of a defective portion or the like, the wafer cross section may be processed by FIB or the like. Prior to the cross-section processing by FIB, it is necessary to put a mark (marker) indicating the processing location on the wafer using an electron beam deposit. By a series of these operations, the cause of defects such as wiring voids and contact defects can be specified, feedback to the manufacturing process can be made, and the yield of products can be improved.

  Next, a second embodiment of the present invention will be described.

  FIG. 14 is a diagram showing an overall configuration of a charged beam apparatus according to the second embodiment of the present invention.

  The charged beam apparatus shown in the figure includes a nanoprober 30 and a cleaning chamber 8A, and other parts are the same as those in the first embodiment.

  A probe (probe) 31 is attached to the tip of the nanoprober 30, and the state of the sample surface (for example, electrical characteristics of a defective portion on the sample) is observed by scanning the probe 31 on the sample 4. To do. In addition to the configuration of the cleaning chamber 8 in the first embodiment, the cleaning chamber 8A has a cleaning object introduction port 19 (see FIG. 15) for introducing a cleaning object. The cleaning object introduction port 19 in the present embodiment is provided to face the gas supply unit insertion port 17.

  When the state of the defect on the sample 4 is observed, a mark is formed around the defect portion with the charged beam 6, the defect portion is searched for on the electronic image using the mark as a mark, and the probe 31 is brought into contact therewith. During observation, since the electron beam (charged beam) 6 is irradiated, the foreign matter itself may be charged depending on the irradiation condition of the electron beam 6 or the irradiation object. At this time, if an insulator is attached to the surface of the probe 31 by an electron beam deposition or the like, the probe 31 may also be charged. When the probe 31 is charged, the foreign matter 32 may be electrostatically adsorbed to the tip of the probe 31 when there is a foreign matter 32 (see FIG. 15) in the vicinity thereof. If the foreign matter 32 is present at the tip of the probe 31 as described above, the foreign matter 32 comes into contact with the region other than the inspection target region and accurate measurement becomes difficult. Therefore, the foreign matter 32 needs to be removed.

  FIG. 15 shows how the probe 31 is cleaned in the charged beam apparatus according to the second embodiment of the present invention. FIG. 15A is a top view of the cleaning chamber 8A, and FIG. 15B is a cross-sectional view thereof.

  In FIG. 15, the gas gun 12 is inserted into the cleaning chamber 8 </ b> A through the gas supply unit insertion port 17, and the probe 31 is inserted into the cleaning chamber 8 </ b> A through the cleaning object introduction port 19. A foreign matter 32 is attached to the tip of the probe 31. As described above, even when the probe 31 becomes a cleaning object in addition to the gas nozzle 12 (gas gun 11), the cleaning process can be performed efficiently as in the first embodiment.

  FIG. 16 is a diagram showing an electron image of the tip of the probe 31 obtained by irradiating the charged beam through the charged beam introduction port 16. FIG. 16A shows an electronic image 44a before the cleaning process, and FIG. 16B shows an electronic image 44b after the cleaning process.

  When cleaning is performed by directly irradiating the charged particle beam 6 to the foreign object 32, the position of the probe 31 is moved to a position where the foreign object 32 can be seen through the charged beam introduction port 16 while using an electron image (secondary electron image). This is good (see FIG. 16A). After the position of the probe 31 is determined, the processing region 33 is designated so that the charged beam (electron beam) 6 can be irradiated on the entire surface of the foreign matter 32 (see FIG. 16A). When the processing region 33 is specified, the foreign matter 32 is removed by irradiating the electron beam 6 with an acceleration voltage of 1 kV and several tens of pA, for example, while jetting a reactive gas (for example, xenon difluoride) from the gas nozzle 12 (FIG. 16 (b)).

  As described above, also in this embodiment, the same effect as that of the first embodiment can be obtained.

  In the above description, the probe 31 of the nano prober 30 is the cleaning target, but the cleaning target is not limited to this. Next, a case where the cleaning target is a probe attached to a cantilever of an atomic force microscope will be described as a modification of the present embodiment.

  FIG. 17 is a diagram showing an overall configuration of a charged beam apparatus which is a modification of the second embodiment of the present invention.

  The illustrated charged beam apparatus includes a cantilever (cantilever) 130 having a probe (probe) 131 attached to the tip instead of the nanoprober 30 described above. Although not specifically shown, the atomic force microscope includes a laser light source that generates laser light, a photodiode that measures the displacement of reflected light of the laser light applied to the probe 131, and the like. It has.

  In the above charged beam apparatus, when the probe 131 approaches the surface of the sample 4, the probe 131 is displaced by an atomic force with atoms on the sample surface, and this displacement is measured with a photodiode using reflected light of the laser beam. To do. When observing the surface state of the sample surface (state of unevenness), the probe 131 (or sample 4) is moved up and down so that the displacement measured by the photodiode is constant, and the uneven state of the sample surface is determined from the amount of displacement. Is detected.

  As in the case of the nanoprober 30, since the sample is irradiated with the electron beam 6 during observation, the foreign matter itself may be charged depending on the irradiation condition of the electron beam and the irradiation object. Further, when an insulator is attached to the surface of the probe 131 by an electron beam deposit or the like, the probe 131 is also charged. When there is a foreign substance on the sample 4 in the vicinity of the probe 131, the foreign substance may be electrostatically adsorbed on the tip. The probe 131 may be brought into contact with the sample 4 or may not be brought into contact. However, in any case, if a foreign substance is attached to the surface of the probe 131, the state of the sample surface cannot be measured accurately. Therefore, it is necessary to remove the foreign matter adhering to the probe 131.

  In this case as well, foreign matter can be effectively removed by inserting the probe 131 into the cleaning object inlet 19 as described above.

  In the above description, the probes 31 and 131 are the objects to be cleaned. However, when there are a plurality of the gas guns 11, it goes without saying that they may be inserted into the cleaning object introduction port 19 for cleaning.

  Next, a charged beam apparatus according to a third embodiment of the present invention will be described. The main feature of the charged beam apparatus according to the present embodiment is that it includes two mirror bodies (twin columns).

  FIG. 18 is a diagram showing an overall configuration of a charged beam apparatus according to the third embodiment of the present invention.

  The charged beam apparatus shown in the figure includes an SEM 46 having the same configuration as the charged beam apparatus described with reference to FIG. 4, and an ion beam generation source (charged beam generation source) 51 that generates an ion beam (see FIG. 19 described later). And the sample holder 3 provided with a cleaning chamber 8A. The SEM 46 is provided with a secondary electron detector 13, an optical microscope 49 used for alignment of the sample 4, and a gas gun 11. A gas gun 11 is provided on the ion beam mirror 45 side. 11, a microsampling unit (extraction means) 47 for extracting a microsample 80 (see FIG. 23 described later) from the sample 4, and a Z sensor 50 for keeping the working distance of the ion beam mirror 45 constant. . For the sake of explanation, the sample 4 in this embodiment is a silicon wafer having a diameter of 300 mm.

  Similarly to the first embodiment, the charged beam apparatus according to the present embodiment also includes a control unit (not shown) that performs control of each device described above. The stage 2 is a 5-axis stage as in the above embodiments, and the sample holder 3 on which the sample 4 is placed can be appropriately moved to the SEM 46 side or the ion beam mirror 45 side. The optical microscope 49 checks several alignment marks on the sample 4 and aligns the sample 4.

  FIG. 19 is a view showing the internal structure of the ion beam mirror 45 in FIG.

  In FIG. 19, an ion beam mirror 45 includes an ion source 51 that generates an ion beam, an extraction electrode (not shown) that extracts the ion beam 66 from the ion source 51, and an anode aperture 53 that determines the diameter of the ion beam 66. An ion beam optical system (charged beam optical system) that irradiates a desired position on the sample 4 with a desired diameter with a polarizer 56, a diaphragm 58, an irradiation lens 59, a projection lens 64, and the like. 300.

  The ion beam generation source (ion source) 51 is preferably one that emits a kind of ion beam (non-contamination ion beam) that does not contaminate the sample (wafer) 4, for example, a duoplasmatron that emits an argon ion beam. Suitable. Other examples include an inert gas ion source, an oxygen or nitrogen gas ion source, a duoplasmatron ion source, an electron cyclotron resonance plasma source, an inductively coupled plasma source, or a helicon wave plasma source. The ion source 51 was lifted about 30 kV in potential using a insulator 52. The ion source 51 is covered with an ion source cover 54 and is air-insulated by the ion source cover 54.

  The ion beam optical system 300 deflects the ion beam in order to remove a neutral particle (metal sputtering etc.) and a mass separator 55 that selects a necessary one (argon ion beam) from the ion beam extracted from the ion source 51. A polarizer 56, a diaphragm 58 for extracting only a necessary portion of the ion beam 66, an irradiation lens 59 for focusing the ion beam 66 narrowed by the diaphragm 58, and a diaphragm projection mask 60 for extracting only a necessary portion of the ion beam 66. And an astigmatism correction coil 61 that corrects astigmatism, an alignment coil 62 that corrects the positional deviation of the ion beam 66, a deflection coil 63 that scans the ion beam 66 over the sample 4, and the projection mask 60. A projection lens 64 for focusing the ion beam 66 is provided.

  The ion source 51 is inclined, for example, several degrees with respect to the central axis on the downstream side of the mirror body 45 so that neutral particles such as metal sputters generated from the ion source 51 do not directly reach the sample 4. (See FIG. 19). The neutral particles travel straight from the ion source 51 and are irradiated to a damper (not shown). The damper (not shown) is preferably made of silicon, carbon or the like in order to prevent metal contamination due to sputtered particles.

  The electrode application voltage and magnetic flux density intensity of the mass separator 55 are adjusted so that the mass separator 55 selects only the argon ion beam from the ion beam extracted from the ion source 51, and the electrode application of the deflector 56 is performed. The voltage is adjusted so that the ion beam bent by the deflector 56 is irradiated to the sample 4 through the diaphragm 58.

  A gun valve (not shown) is provided between the sample chamber 1 and the ion beam mirror 45 to separate them. This gun valve (not shown) is used when it is desired to leak only the sample chamber 1 during maintenance or the like. The deflection coil 63 scans the sample 4 with a circular ion beam for observation that has passed through the projection mask 60. Next, the projection mask 60 will be described in detail.

  20 is a top view of the projection mask 60, and FIG. 21 is a partially enlarged view thereof.

  In FIG. 20, the projection mask 60 includes slit holes 71 (71a, 71b) used when extracting a microsample 80 (see FIG. 23 described later) from the sample 4, and a vertical used when processing the sample into a thin film. A slit hole 72 having a relatively large lateral aspect ratio, a slit hole 73 for a deposit, and a round hole 74 (74a, 74b) for an observation beam are opened, and only an ion beam that has passed through each of these holes. Is condensed by the projection lens 64 and irradiated onto the sample 4. The slit hole 71 for extracting the microsample 80 includes a U-shaped slit 71a and a single-character slit 71b, which are properly used when extracting the microsample 80. Similarly, the round hole 74 also has two types of holes 74a and 74b having different diameters.

  The projection mask 60 can be moved in a direction substantially perpendicular to the ion beam axis (that is, a horizontal direction) by a drive unit (not shown), and the beam shape is changed through the various holes described above. It can be projected onto the sample 4. In this figure, each type of slit hole is provided one by one, but it is also possible to devise a technique for extending the life of the projection mask 60 by providing a plurality of the same type and appropriately using them. The projection mask 60 is preferably made of silicon in order to prevent metal contamination.

  FIG. 21 shows the projection mask 60 being irradiated with the non-contaminating ion beam 66. As shown in the drawing, the dimension of the micro-sampling extraction slit hole 71a is, for example, about 0.4 × 0.5 mm, and the ion beam 66 is irradiated so as to cover the entire surface of the slit hole 71a. . Thereby, the shape of the ion beam 66 can be made into the same U-shape as the slit hole 71a.

  The ion beam mirror 45 configured as described above has two types of beam modes, ie, a projection mode mainly used for cross-section processing of a sample and an observation mode mainly used for obtaining an electron image of the sample. . Next, the configuration of the ion beam optical system 300 in each of these modes will be described.

  FIG. 22 is a diagram showing two beam modes by the ion beam optical system 300 in the ion beam mirror 45, in which (a) shows a projection mode and (b) shows an observation mode.

  In the projection mode shown in FIG. 22A, the irradiation lens 59 is adjusted so that an image from the anode aperture 53 is formed at the principal point of the projection lens 64. This adjustment is performed by applying a high voltage to the central lens of the irradiation lens 59 composed of a set of three butler lenses. The projection lens 64 forms an image from the projection mask 60 on the sample 4. The projection lens 64 is also formed of a triplet butler lens, and is used by applying a high voltage only to the central electrode.

  On the other hand, in the observation mode shown in FIG. 22B, the irradiation lens 59 forms an image from the anode aperture 53 once on the upstream side of the projection mask 60, and the image formed by the projection lens 64 is used for the sample 4. The image is formed again on the top. Thereby, the reduction ratio of the image can be reduced to about 1/30 of the projection mode, and a beam having a minimum diameter of about 0.1 to 0.2 μm can be obtained. By scanning this beam with the deflection coil 63 on the sample 4, a secondary electron image having a higher resolution than that in the projection mode can be obtained.

  FIG. 23 is a view showing the cartridge mechanism unit 75 arranged on the sample holder 3 (see FIG. 2).

  The illustrated cartridge mechanism unit 75 includes a cartridge 81 having a mesh 82 to which a microsample 80 extracted from the sample 4 is bonded, and a cartridge holder that holds the cartridge 81 so as to be movable back and forth in the axial direction (the direction of arrow C in the figure). 83 and a gear 84 that transmits rotational power to the cartridge holder 83.

  The microsample 80 is obtained by irradiating the sample 4 with the ion beam 66 in the above-described projection mode, and is formed into an appropriate shape and size (for example, about 10 μm). The micro sample 80 is adhered to the mesh 82 of the cartridge 81 by a deposit. In order to mount the microsample 80 extracted from the sample 4 on the mesh 82 in this way, the contact portion of the microsample probe (probe) 48 with the microsample 80 may be cut by a non-contaminating ion beam.

  The cartridge 81 is detachably attached to the cartridge holder 83, and only the cartridge 81 can be taken out of the apparatus.

  The cartridge holder 83 is rotated 180 degrees in the positive and negative directions as indicated by an arrow D in the figure by a gear 84 rotated by a driving device (not shown: for example, a motor) provided in the sample holder 3. Driven. The cartridge 81 can be held at an angle suitable for processing the microsample 80 by appropriately rotating the cartridge holder 83 with this rotating mechanism. For example, when thin film processing is performed on the microsample 80, the direction of the ion beam emission axis and the direction of thinning can be adjusted.

  The probe 48 is preferably made of silicon, and if made of silicon, there is less concern about metal contamination compared to tungsten or the like. Note that the probe 48 may be made of, for example, carbon, germanium, or the like other than silicon.

  In the case of observing the surface of the sample 4 in the charged beam apparatus configured as described above, the sample 4 is moved to the SEM 46 side by the stage 2, the sample 4 is irradiated with the electron beam 19 by the SEM 46, and the voltage contrast (VC ) To find the defective part. For example, when the contact portion is observed, if there is a contact failure, the defective portion is observed darkly. This is because, due to the contact failure, the irradiated charge is less likely to flow to the ground, so that the defective portion is positively charged, and the secondary electrons are trapped by the secondary electrons detected by the secondary electron detector 16. This is because the amount decreases.

  In this way, the size of the defect (for example, contact hole) detected by VC is as small as several tens of nanometers. In order to perform more detailed observation, the sample 4 is processed by the ion beam mirror 45 and then the TEM. It is necessary to observe with etc. In order to process with the ion beam mirror 45, it is necessary to mark the sample 4 with a mark of the processing point by GAD by the SEM 46. When performing GAD, the gas gun 11 attached to the SEM 46 side is used.

  FIG. 24 is a diagram showing an electronic image 94 of the sample 4 after mark formation by GAD.

  The illustrated electronic image 94 is formed with a defect portion 96 that is observed darker than the surrounding normal contact holes, and a predetermined interval (for example, about several μm) on both sides of the defect portion 96 2. Two marks 97 are provided. The mark 97 has a relatively low acceleration voltage (for example, about 1 kV) for maximizing the deposition rate, and irradiates a mark of several μm square for several minutes by irradiating an electron beam of several tens of pA. It was formed by electron beam irradiation.

  Next, the defective portion is moved directly below the non-contaminated ion beam mirror 45 by the stage 2. At this time, if the position cannot be aligned with the position accuracy of the stage 2, the defect portion 96 is searched based on the positional relationship with the SIM image of the mark 97 on the sample 4.

  Subsequently, in the projection mode (see FIG. 22A), the sample 4 is irradiated with the ion beam 66 through the slit hole 71 or the like of the projection mask 60, and the microsample 80 including the defect portion 96 and the mark 97 from the sample 4 (see FIG. 22A). 23). The microsample 80 thus formed is extracted from the sample 4 by using the microsampling probe 48 (see FIG. 23), and is adhered to the mesh 82 (see FIG. 23) of the cartridge mechanism unit 75.

  FIG. 25 is a diagram illustrating a state in which the microsample 80 mounted on the mesh 82 is thinned for a TEM sample.

  The thinning process is performed in the projection mode shown in FIG. In the projection mode, as described above, it is difficult to obtain a sufficient resolution for designating a region to be thinned. First, the thinning position is determined in the observation mode shown in FIG. It should be noted that the beam in the observation mode and the beam in the projection mode have different optical conditions as described above, and beam position deviation due to axial deviation may occur. In such a case, it is preferable to obtain the amount of deviation in advance by designating the machining position in the observation mode, and to perform thinning by correcting the deviation and designating a processing region to be thinned.

  When thinning the microsample 80, the ion beam is passed through the thinning slit 72 (see FIG. 20) of the projection mask 60 and scanned by the deflection coil 63, and the microsample 80 is moved by the projection lens 64. Direct imaging on top. In order to make the cross section to be thinned into a sharp processed surface, as shown in FIG. 23, the major axis direction (Y direction in FIG. 25) of the slit hole 72 is changed to the major axis direction (Y direction) of the microsample 80. It is good to match. In this way, aberrations such as spherical aberration can be reduced near the beam center, so that the processed surface can be made sharper. Such a thinning process is repeated to obtain a microsample 90 that has been thinned.

  By using the microsample 90 thus obtained, a transmission electron image with higher resolution can be obtained. In this case, for example, the cartridge 81 is rotated 90 degrees by the rotation mechanism of the cartridge holder 83 shown in FIG. 23, and a high voltage (about 200 kV) is applied thereto to irradiate and transmit the accelerated electron beam. An electron image can be obtained by detecting the beam with a detector.

  Even when the above-described operation is performed, there is a risk that deposits may be attached to the gas gun 11 due to GAD, or foreign substances may be attached to the probe 48, and these must be removed as appropriate. However, in this case as well, the cleaning process can be performed efficiently by using the cleaning chamber 8A provided on the sample holder 3 as in the above embodiment. Therefore, the present embodiment can provide the same effects as those of the above embodiment.

  Next, the charged beam apparatus which is the 4th Embodiment of this invention is demonstrated. The main feature of the charged beam apparatus according to the present embodiment is that the central axes of two mirrors intersect on the sample 4.

  FIG. 26 is a diagram showing an overall configuration of a charged beam apparatus according to the fourth embodiment of the present invention.

  The charged beam apparatus shown in the figure is configured such that the extension of the central axis of the SEM 46 and the extension of the central axis of the ion beam mirror 45 intersect on the sample 4 fixed to the sample holder 3. That is, the present embodiment can irradiate a charged beam from the SEM 46 and the ion beam mirror 45 without moving the stage 2 as in the third embodiment. The surface can be observed as it is with an electron beam. Also in this charged beam apparatus, a cleaning chamber 8 A is provided on the sample holder 3.

  Compared with the second embodiment, the charged beam apparatus configured in this way can arrange a charged beam mirror body, a gas gun, a microsampling unit, and the like in an integrated manner, and a compact apparatus. The point which can be comprised is excellent.

  Also in the charged beam apparatus configured as described above, the gas gun 11 and the like can be cleaned in the cleaning chamber 8A, and therefore the same effects as those of the above-described embodiment can be obtained.

The figure which shows the whole structure of the charged beam apparatus which is the 1st Embodiment of this invention. The top view of the sample holder 3 in the 1st Embodiment of this invention. Sectional drawing of the cleaning chamber 8 in the 1st Embodiment of this invention. The figure which shows the internal structure of the charged beam mirror body 10 in the case of having an electron source. Sectional drawing which expands and shows the gas gun 11 vicinity in FIG. The figure which shows an example of the graphical user interface (GUI) displayed on the display part 180 in the 1st Embodiment of this invention. The figure which shows a mode that the gas gun 11 is cleaned in the 1st Embodiment of this invention. The figure which shows the other mode of cleaning the gas gun 11 in the 1st Embodiment of this invention. The figure which shows a mode that the end point of a cleaning process is detected using EDX in the 1st Embodiment of this invention. The figure which shows the elemental-analysis result when tungsten adheres to the surface of the gas nozzle 12 made from SUS when tungsten carbonyl is used as the reactive gas 18 in the 1st Embodiment of this invention. The figure which shows the elemental-analysis result when silicon oxide adheres to the surface of the gas nozzle 12 made from silicon when tetraethyloxysilane is used as the reactive gas 18 in the first embodiment of the present invention. The figure which shows a mode that the charged beam and reactive gas are irradiated to the sample in a charged beam apparatus. The figure which shows a mode that depot is performed when the insulating deposit | attachment 214 adheres to the gas nozzle 212. FIG. The figure which shows the whole structure of the charged beam apparatus which is the 2nd Embodiment of this invention. The figure which shows a mode that the probe 31 is cleaned in the 2nd Embodiment of this invention. The figure which shows the electronic image of the probe 31 tip part obtained by irradiating a charged beam through the charged beam introducing port 16 in the 2nd Embodiment of this invention. The figure which shows the whole structure of the charged beam apparatus which is a modification of the 2nd Embodiment of this invention. The figure which shows the whole structure of the charged beam apparatus which is the 3rd Embodiment of this invention. The figure which shows the internal structure of the ion beam mirror 45 in the 3rd Embodiment of this invention. The top view of the projection mask 60 in the 3rd Embodiment of this invention. The elements on larger scale of the projection mask 60 of FIG. The figure which shows two beam modes by the ion beam optical system 300 in the ion beam mirror 45 in the 3rd Embodiment of this invention. The figure which shows the cartridge mechanism part 75 arrange | positioned on the sample holder 3 in the 3rd Embodiment of this invention. The figure which shows the electronic image 94 of the sample 4 after forming the mark by GAD in the 3rd Embodiment of this invention. The figure which shows a mode that the micro sample 80 mounted in the mesh 82 in the 3rd Embodiment of this invention is thinned for TEM samples. The figure which shows the whole structure of the charged beam apparatus which is the 4th Embodiment of this invention.

Explanation of symbols

3 Sample holder 4 Sample 6 Charged beam (electron beam, ion beam)
8 Cleaning chamber 10 Charged beam mirror 11 Gas gun (gas supply unit)
12 Gas nozzle 13 Secondary electron detector 14 Dirt film (attachment)
16 Charged beam introduction port 17 Gas supply unit insertion port 18 Reactive gas 19 Cleaning object introduction port 20 Electrode (positive potential)
24 electrodes (negative potential)
30 Nanoprober 31 Probe 35 EDX (Cleaning end point detection means)
37 GUI screen 38 Message display section 46 Air cylinder (drive device)
47 Micro sampling unit 48 Micro sample probe 51 Ion source (charged beam generation source)
80 Microsample 121 Rotation drive device 130 Cantilever 131 Probe 150 Control unit 151 Electron source (charged beam generation source)
165 Electron beam optical system (charged beam optical system)
180 Display unit 300 Ion beam optical system (charged beam optical system)

Claims (24)

A charged beam source for generating a charged beam;
A charged beam optical system that focuses the charged beam from the charged beam generation source and irradiates the sample; and
A gas supply unit for supplying a reactive gas to the charged beam irradiation part on the sample;
A charged beam apparatus comprising: a gas supply unit insertion port for inserting the gas supply unit; and a cleaning chamber provided in the sample chamber, having a charged beam introduction port for introducing a charged beam. . The charged beam device according to claim 1.
A charged beam apparatus comprising: a driving device that moves the gas supply unit in the sample chamber. The charged beam device according to claim 2.
The charged beam device according to claim 1, wherein the driving device rotates the gas supply unit about its axis. The charged beam device according to claim 1.
The charged beam apparatus according to claim 1, wherein the cleaning chamber has a cleaning object introduction port for introducing a cleaning object. The charged beam apparatus according to claim 4.
Provided with another gas supply unit for supplying a reactive gas to the charged beam irradiation part on the sample,
The charged beam apparatus, wherein the cleaning object is the other gas supply unit. The charged beam apparatus according to claim 4.
It has a nano prober with a probe that observes the state of the sample surface,
The charged beam apparatus, wherein the cleaning object is the probe. The charged beam apparatus according to claim 4.
A cantilever to which a probe for observing the state of the sample surface is attached, and an atomic force microscope for obtaining the surface shape of the sample from the force acting between the probe and the sample;
The charged beam apparatus, wherein the cleaning object is the probe. The charged beam device according to claim 1.
The charged beam apparatus, wherein the cleaning chamber is provided on a sample holder on which a sample is placed. The charged beam device according to claim 1.
Comprising an electron detection means for detecting electrons from the sample;
The charged beam apparatus, wherein the cleaning chamber has an inner wall surface to which a potential is applied. The charged beam device according to claim 9.
The charged beam apparatus according to claim 1, wherein a positive potential is applied to the inner wall surface on the electron detection means side, and a ground potential or a negative potential is applied to the other inner wall surface. The charged beam device according to claim 1.
A charged beam apparatus comprising: a cleaning end point detecting unit that detects an end point of the cleaning process of the gas supply unit. The charged beam device according to claim 11.
The cleaning end point detection unit has a charged beam irradiation unit that irradiates the gas supply unit with a cleaning end point detection charged beam, and is emitted by irradiating the end point detection charged beam to the gas supply unit. A charged beam apparatus that detects an end point of a cleaning process by detecting an X-ray and performing elemental analysis at the charged beam irradiation point based on the detected characteristic X-ray. The charged beam device according to claim 12, wherein
The charged beam apparatus according to claim 1, wherein the end point detection charged beam is emitted from the charged beam generation source. The charged beam device according to claim 1.
Notification means for notifying the cleaning timing of the gas supply unit in response to an input signal;
Based on the irradiation condition of the charged beam from the charged beam generation source, the dirt adhering to the gas supply unit is predicted and calculated, and when the predicted calculation value reaches a threshold value or more, the cleaning time of the gas supply unit is determined. A charged beam apparatus comprising a control device that outputs a signal to be notified to the notification means. The charged beam device according to claim 1.
A charged beam apparatus comprising a control device that performs automatic review and automatic classification of defects in a sample. The charged beam device according to claim 1.
A charged beam apparatus comprising: extraction means for extracting a microsample from a sample. The charged beam device according to claim 16, wherein
An ion beam source for generating an ion beam;
With other charged beam optical system for focusing the ion beam from the ion beam generation source and irradiating the sample,
The charged beam generation source is an electron beam generation source. The charged beam device according to claim 16, wherein
The charged beam apparatus characterized in that the material of the extraction means is any one of silicon, carbon, and germanium. The charged beam device according to claim 1.
The charged beam generation source is any one of an inert gas ion source, an oxygen or nitrogen gas ion source, a duoplasmatron ion source, an electron cyclotron resonance plasma source, an inductively coupled plasma source, or a helicon wave plasma source. Characteristic charged beam device. The charged beam device according to claim 1.
The charged beam generating source is a group IV liquid metal ion source such as silicon or germanium. The charged beam device according to claim 1.
The charged beam generator is a gas phase field ion source such as helium or argon. In a cleaning method for a charged beam apparatus that performs observation / analysis or processing of a sample by irradiating a charged beam,
A charged beam from a charged beam generation source is focused through a charged beam optical system, and the charged beam focused by the charged beam optical system is connected to the cleaning chamber through a charged beam introduction port provided in a cleaning chamber in the sample chamber. Introduced into the
A gas supply unit for supplying a reactive gas to the charged beam irradiation portion on the sample is inserted into the cleaning chamber through a gas supply unit insertion port provided in the cleaning chamber;
A cleaning method for a charged beam apparatus, wherein dirt adhered to the gas supply unit is removed in the cleaning chamber. In the cleaning method of the charged beam apparatus according to claim 22,
A charged beam apparatus cleaning method, wherein a charged beam is directly irradiated onto the gas supply unit inserted in the cleaning chamber. In the cleaning method of the charged beam apparatus according to claim 22,
A charged beam apparatus cleaning method, wherein the gas supply unit inserted into the cleaning chamber is introduced into the cleaning chamber without directly irradiating the charged beam.

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