JP5241273B2 - Charged particle device and method of use - Google Patents

Description

  The present invention relates to a charged particle apparatus such as a scanning electron microscope (SEM) or a focused ion beam (FIB) processing observation apparatus, and a method of using the charged particle apparatus.

  As charged particle beam processing apparatuses, FIB processing observation apparatuses and ion milling apparatuses are known. These apparatuses are used for sample preparation when a defect portion of a sample is cross-sectionally observed with a transmission electron microscope (TEM), an SEM, or the like. FIB processing and observation equipment scans the surface of a sample with a focused ion beam, detects secondary charged particles generated during the scanning, and observes it as an image while accurately processing a specific part such as a defect. Widely used as a process evaluation system.

  In the ion beam processing, in order to prevent spatter particles from reattaching to the mask pattern and the processing surface and generating burrs on the sample, Japanese Patent Application Laid-Open No. 2005-135867 discloses a space on the processing surface of the processing sample. By arranging an electrode for generating an electric field on the surface and applying 0 V or a negative voltage to the sample, it is possible to perform processing without depositing scattered substances generated when the ion beam is irradiated on the sample surface. Technology is disclosed.

JP 2005-135867 A

  When a sample is processed using a charged particle beam in an FIB processing observation apparatus or the like, scattered substances generated during processing contaminate the observation surface, or adversely affect image observation such as narrowing the observation area. In SEM and the like, when a charged particle beam is scanned on a sample for observation / analysis, the sample surface, the gas molecules contained therein and the residual gas molecules in vacuum are polymerized by charged particle beam irradiation, and the sample surface To deposit. When these materials are processed / observed / analyzed, scattered materials or contaminants generated during processing or observation are deposited at or around the place where the charged particle beam is irradiated, so the observation area is contaminated. Or narrow the observation area.

  In order to secure the observation region, it is necessary to process / observe while processing it more than necessary or confirming whether the observation region is hindered by the scattered material deposited.

  Since these operations are cumbersome and cause a reduction in work efficiency, it is desired to develop mechanisms and methods that reduce the effects of scattered substances and contaminants.

  However, the known method is not sufficient to solve the problem.

  Therefore, the present invention effectively suppresses deposition on the sample due to a part of the sample generated from the sample scattered from the sample by the charged particle beam irradiation, contamination, and other samples by the charged particle beam device.

  One aspect of the present invention is a charged particle source, an optical mechanism that irradiates a sample with charged particles generated from the charged particle source, and a detection mechanism that detects charged particles generated from an irradiated region of the sample by irradiation with charged particles. And an attachment mechanism that attaches a part of the sample separated from the sample by the irradiation, and is formed so as to be disposed at a position corresponding to the irradiated region.

  A part of the sample separated from the sample may be a scattered substance generated when scanning charged particles, or a substance different from the sample component deposited on or included in the sample surface (for example, contamination). Substance, gas molecule).

  Or a first attachment step of irradiating a first region on the sample with charged particles generated from a charged particle source, and attaching a part of the sample generated from the first region to the attachment mechanism by the irradiation; And a first removal step of removing the attached portion. Alternatively, in addition, a second region on the sample is irradiated with charged particles, and a part of the sample generated from the second region by the irradiation is attached to the attachment mechanism after the removal. A method for using a charged particle device comprising: an attaching step; and a second removing step for removing the attached portion.

  In addition, the present invention proposes a probe mechanism and a processing observation method having a function of reducing scattered substances or contaminants that are problematic in a charged particle beam apparatus that performs processing / observation / analysis.

  The mechanism and specific configuration of the present invention will be described in the following embodiments of the invention.

  The following can be considered as another invention different from the above invention. A charged particle beam source; an optical system that scans the sample with a charged particle beam generated from the charged particle beam source; and a detection system that detects a signal generated from the sample surface by charged particle beam irradiation. Observation / analysis or a charged particle beam device that forms a protective film on the surface. It has a probe mechanism and a mechanism that can apply a positive or negative voltage to the probe. Is to do. Carbon, metal, or other wiring is provided so that the vapor deposition material can be heated by applying a voltage. Or it is the processing method characterized by using the produced vapor deposition substance as a protective film. Alternatively, when the protective film is formed, the probe is brought into contact with the vicinity of the sample and the sample, whereby the charged particle beam is scattered by collision with the gas molecules for forming the protective film, and a protective film is formed in a region other than the designated region. This is a processing technique characterized in that this can be prevented.

  According to the present invention, it is possible to suppress deposition on a sample by a part of the sample generated from the scattered material, contaminants, and other samples of the sample generated from the sample by charged particle irradiation in the charged particle beam apparatus.

  The embodiments of the present invention may be applied to SEM, FIB processing observation apparatus, and other charged particle apparatuses. In addition, it relates to methods such as processing, observation and analysis using charged particle beams, and may be applied regardless of fields such as semiconductors, materials, and organisms.

  Further, the present invention is not limited to the present embodiment, but allows improvements and changes.

(First embodiment)
FIG. 2 shows a schematic configuration diagram of a general FIB in the charged particle beam apparatus.

  This apparatus has an ion gun chamber 202 having an ion source 201 for taking out the charged particle beam 101 and an optical mechanism for scanning and irradiating the generated ions on the sample. Specifically, it has a focusing lens 203, a deflector 204, and an objective lens 205, and an exhaust for maintaining a vacuum in a sample chamber 212 having a sample stage 210, a probe 207, a deposition gas molecule supply unit 213, and a detector 209. It consists of pumps 211 and the like.

  The charged particle beam 101 taken out from the ion source 201 is finely focused by the focusing lens 203 and the objective lens 205, and scans the sample 102 by the deflector 204. Sample processing is performed by a sputtering phenomenon generated by collision of ions with the sample 102 by irradiation of the ion beam 101. The secondary charged particles 206 emitted from the scanned sample 102 are captured by the detector 209 to form an image.

  FIG. 3 is a schematic diagram showing an embodiment of the present invention, and particularly shows a case where the present invention is applied to an FIB processing observation apparatus.

  Here, the ion beam 101 is formed so as to be disposed at a position corresponding to the irradiated region in the sample, and has a rod shape having a region that narrows toward the end as an attachment mechanism for attaching a part of the sample separated from the sample by irradiation. An example using the probe is shown. For example, the tip of the probe has a drive mechanism that moves independently of the stage and the sample chamber wall. Thereby, it can be located in the desired area | region on a sample.

  As shown in FIG. 3 a, a probe 207 having the characteristics of the present invention is arranged in the vicinity of the ion beam 101. In FIG. 3A, although it is arranged on the left side of the charged particle beam, the probe 207 can be arranged at any location as long as it is in the vicinity of the ion beam 101.

  Next, the collection state of the scattered substance 103 is shown in FIG. When processing is performed with the ion beam 101, the scattered material 103 is generated from the portion irradiated with the ion beam 101.

  The scattered substance 103 generated by irradiating the ion beam 101 is adsorbed by the probe 207 having a lower temperature than the processing part to which heat is applied and its periphery by irradiating the ion beam 101. Therefore, it is possible to perform processing while reducing the contamination of the observation surface 104 with the scattered substance 103.

  Here, the comparative example when not using the Example of the said this invention is shown. An example of sample processing with a charged particle beam by the FIB processing observation apparatus is shown in FIG. When the charged particle beam 101 is scanned on the sample 102 as shown in FIG. 1A, when the charged particle beam 101 is irradiated as shown in FIG. Since the scattering material 103 is deposited on the manufactured observation surface 104 and the processed region 105, it is a bad effect for image observation. On the other hand, the problem of the comparative example can be effectively suppressed by implementing the embodiment of the present invention.

  In this way, we propose a method and mechanism for processing / observing / analyzing using a probe having a function of reducing scattered substances or contaminants, which is a problem when processing / observing / analyzing with a charged particle beam apparatus. can do.

  FIG. 4 is a schematic diagram showing an embodiment of the present invention, and particularly shows a case where the present invention is applied to an SEM.

  As shown in FIG. 4 a, a probe 207 is disposed in the vicinity of the electron beam 101. In FIG. 4 a, it is arranged on the left side of the electron beam, but the probe 207 can be arranged at any location as long as it is near the electron beam 101. When the electron beam 101 is scanned, heat is applied to and around the scanned location, so that the surface of the sample 102 and internal gas molecules are released. This gas molecule causes sample contamination as the contaminant 103. Similarly, residual gas molecules in the sample chamber also cause sample contamination as the contaminant 103.

  The collected state of the pollutant 103 is shown in FIG. 4b. By irradiating the electron beam 101, the pollutant 103 is collected by the probe 207 having a temperature lower than that of the scanned place where the heat is applied and the vicinity thereof. Thereby, observation can be performed without contamination of the surface of the sample 102.

  In this way, scattered substances generated during sample processing can be collected. Alternatively, contaminants deposited on the sample surface during sample observation can be collected. For this reason, it can suppress that these substances adhere to a processing field and an observation field effectively.

  FIG. 5 is a schematic diagram showing an embodiment of a mechanism for causing the charged particle beam and the probe to follow the present invention.

  As shown in FIG. 5, the mechanism for causing the probe 207 to follow includes a probe unit including the probe 207 and the probe driving unit 208, and a probe control mechanism 504 that controls the probe driving unit 208. The charged particle beam apparatus main body includes a charged particle optical system in which the charged particle beam 101 emitted from the charged particle beam source 201 is finely focused by the focusing lens 203 and the objective lens 205 and scanned on the sample 102 by the deflector 204. , And a charged particle beam control mechanism 502 for controlling it. These pieces of operation information are managed by the control computer 503, and can follow the movements of the probe 207 and the charged particle beam 101.

  For example, as shown in FIG. 3, when performing sample processing using the ion beam 101 in the FIB processing observation apparatus, the probe 207 is disposed behind the charged particle beam 101 in the scanning direction, thereby observing the observation surface 104. It is possible to reduce the scattering material 103 that hinders the above.

  As shown in FIG. 4, when performing observation using the electron beam 101, the probe 207 is arranged so as not to enter the observation field of view, so that the pollutant 103 can be trapped without deteriorating the image observation. Can be collected. These can be switched by selecting a processing mode or an observation mode with the control computer 503 of the charged particle beam apparatus.

  In addition, it is possible to provide a processing observation method that can reduce deposition of contaminants or scattered substances on a sample by moving the probe following the charged particle beam to be scanned.

  Note that the probe may be moved corresponding to the movement of the position of the beam irradiation area on the sample. On the other hand, when the sample has a plurality of irradiation targets, when the first irradiation target is irradiated, the probe is installed at the first position near the irradiation region, and the second irradiation region is irradiated. It is also conceivable to move the probe so as to be installed at a second position in the vicinity of the irradiation area. The former can maintain the distance to the beam irradiation region more uniformly, while the latter has a slight change in the distance to the beam irradiation region due to scanning, but can be controlled easily and efficiently. .

  FIG. 6 is a schematic view showing an embodiment of a mechanism for cooling the probe of the present invention.

  As shown in FIG. 6, the mechanism for cooling the probe 207 includes a probe 207, a probe driving unit 208 for driving the probe, a container 602 for containing a refrigerant, a refrigerant 601, and a wiring 603 for connecting the refrigerant and the probe. For the refrigerant 601, for example, liquid nitrogen, liquid helium, dry ice, or the like is used. For the wiring 603 that connects the refrigerant and the probe, for example, a material having good thermal conductivity such as Cu (copper) or Al (aluminum) is used. At least a member having better thermal conductivity than a member around the wiring is used.

  Thereby, the heat of the refrigerant 601 is transmitted through the wiring 603 connecting the refrigerant and the probe, and the probe 207 can be cooled.

  In FIG. 6, the cooling method using the refrigerant 601 is taken as an example, but the probe 207 can be cooled using a Peltier element or the like. Moreover, a probe can be adjusted to arbitrary temperature by combining a heater.

  For example, when processing a sample (polymer material such as rubber or plastic) whose shape is easily deformed by heat using an FIB processing observation apparatus, if processing is performed using the ion beam 101 having a high irradiation current, an unprocessed portion is formed. However, the heat changed and the shape changed. In such a case, processing is performed using the ion beam 101 having a low irradiation current in order to prevent the temperature of the sample from being increased. However, since the processing takes a long time, a reduction in work efficiency has been a problem. Further, by using a cryostage to process the sample while cooling, deformation due to the ion beam 101 can be prevented, but lacks versatility such as requiring a long time for cooling the stage.

  By arranging the probe 207 with a cooling mechanism in contact or in the vicinity thereof, the processing can be performed while cooling. As a result, even if the sample is processed using the charged particle beam 101 having a high irradiation current, the unprocessed portion is cooled, so that the shape can be processed in a short time without being deformed by heat.

  In addition, it is possible to provide a processing observation method characterized in that processing can be observed while the probe is endothermic or locally cooled by bringing the probe in the vicinity of the sample or in contact with the sample.

  Further, by cooling the probe 207, there is an effect of improving not only the cooling of the sample but also the collection efficiency of the scattered substance or the pollutant 103 which is a causative substance of the sample contamination.

  FIG. 7 is a schematic diagram showing an embodiment of a mechanism for heating the probe of the present invention.

  As shown in FIG. 7, the mechanism for heating the probe 207 includes a probe 207, a probe driving unit 208, a heater 701, a power source 702, and a wiring 703 that connects the heater 701 and the power source 702.

  The heater 701 is heated, and this heat is transmitted to the tip of the probe 207 to heat the tip of the probe 207. The temperature of the heater 701 can be changed by a power source 702.

  In FIG. 7, the method of heating using the heater 701 is taken as an example, but the probe 207 can be heated even if hot water or the like is put in the container 602 containing the refrigerant in FIG. 6.

  For example, in the case of a sample containing many gas molecules during SEM observation, the sample was heated before observation. As a result, it was possible to release gas molecules that were present on the sample surface and in the interior, and to reduce contaminants adsorbed during observation. However, since heating is performed in the air, if the sample is not observed immediately after the heating is stopped, gas molecules re-adsorb on the sample and, in the case of a sample that is easily oxidized, the harmful effect of promoting the oxidation of the sample There was also.

  If a probe having a heating mechanism is used, the sample can be locally heated in the sample chamber by contacting or arranging the probe in the vicinity of the observation region. Further, since heating is performed in the evacuated sample chamber, the gas molecules contained in the sample can be released more efficiently, and even a sample that is easily oxidized can be heated while suppressing oxidation due to heating as much as possible.

  Further, by heating the probe 207 without the sample 102 in the sample chamber 212, the scattered material or the contaminant 103 adsorbed on the probe 207 can be dissociated and cleaned.

  In addition, it is possible to provide a processing observation method characterized in that processing and observation can be performed while locally heating the sample by bringing the probe close to or in contact with the sample.

  As the probe used in the present invention, an arbitrary shape can be selected according to each use of processing / observation / analysis. FIG. 8 is a schematic diagram showing an example of a processing technique using the arbitrary shape probe of the present invention.

  For example, a probe, which is an adhesion mechanism of scattered substances, is formed so that the surface area of the tip side region disposed in the region corresponding to the irradiation position of the charged particles is larger than the surface area of the support portion side region than the tip side region. This time, as an example, a ring probe is shown. The surface area of the ring portion region located on the distal end side is formed so as to be larger than the surface area of the rod-like region on the support portion side. For example, the width of the tip side region is wider than the width of the support portion side region.

  As shown in FIG. 8, the arbitrary-shaped probe includes a charged particle beam 101, a sample 102, and an arbitrary-shaped probe 801. By irradiating the charged particle beam 101, the scattered substance or contaminant 103 is adsorbed on the ring-shaped surface of the probe. In the case of this shape, the surface area is significantly larger than that of the above-described pointed probe, so that the scattered material or contaminant 103 can be efficiently collected. Thus, by selecting the shape of the probe, it is possible to improve the collection efficiency of the scattered substance or the contaminant 103, the cooling efficiency of the sample, and the heating efficiency.

  In addition, the tip of the probe can be used in place of the protective film by processing in the vicinity of or in contact with the sample. As a result, the time for producing the surface protective film can be shortened and the working efficiency can be improved.

  In addition, it has a support mechanism that can be controlled to place the end on the sample to be irradiated with charged particles, and the end is arranged corresponding to the irradiation region that irradiates the sample with charged particles generated from the charged particle source, The sample is irradiated with charged particles, a region where the sample is irradiated with charged particles, and a region where the sample is suppressed from being irradiated with charged particles by the support mechanism are formed. For example, when forming a protective film, by contacting the probe in the vicinity of the sample and the sample, even if charged particle beam and protective film forming gas are supplied, the region where the protective film is formed and the formation of the protective film A region for suppressing the above is formed. For this reason, it can prevent that a charged particle beam is scattered by collision with the gas molecule for protective film formation, and a protective film is formed in areas other than the designated area.

  FIG. 9 is a schematic view showing an embodiment of the probe surface treatment method of the present invention.

  This time, an example of probe tip processing using charged particle beam is shown.

  When the charged particle beam 101 is irradiated to the tip of the probe 207 as shown in FIG. 9a, an uneven shape can be produced at the tip of the probe 207 as shown in FIG. 9b. Thereby, since the surface area of the tip of the probe 207 can be increased, the collection efficiency of the scattered substance or the contaminant 103 can be improved.

  In addition, the adsorbed scattered material or contaminant is removed by cutting the tip portion of the probe 207 on which the scattered material or contaminant 103 is deposited with the charged particle beam 101 without the sample 102 in the sample chamber 212. can do.

  In FIG. 9, the surface treatment of the probe 207 is performed using the charged particle beam 101, but the same effect can be obtained even if chemical etching or dry etching is performed.

  FIG. 10 is a schematic diagram showing an embodiment of a mechanism for applying a voltage to the probe of the present invention.

  As shown in FIG. 10, a mechanism for applying a voltage to the probe includes a probe 207, a probe driving unit 208 for driving the probe, a power source 702, a wiring 703 connecting the probe 207 and the power source 702, and a wiring 703 connecting the power source and the ground 1001. It consists of The wiring 703 uses a material having good conductivity such as Cu (copper), Al (aluminum), Ag (silver), or the like. By applying a voltage with the power source 702, the voltage flows through the wiring 703 connecting the probe 207 and the power source 702, and the voltage is applied to the probe 207. The voltage applied to the probe 207 can be varied depending on the voltage applied by the power source 702. Thereby, an arbitrary voltage can be applied to the probe or the sample. By bringing the probe into contact with the sample and applying an appropriate negative voltage to the sample, it is possible to suppress the adhesion of scattered substances to the sample. In addition, it is possible to improve the collection efficiency of scattered substances by applying an appropriate positive voltage without contacting the sample to the probe.

  Further, in a state where the sample 102 is not in the sample chamber 212, the probe 207 is heated by applying a positive or negative high voltage for a short time, and the deposited scattered substances or contaminants 103 are dissociated from the probe 207 to clean the probe 207. Can be

  Thus, when cleaning, it is preferable to apply a voltage on the negative side of the voltage used for adhesion, such as zero or a negative voltage.

(Second Embodiment)
Other examples are shown below. An application example not related to the above embodiment will be described using the basic configuration of the above embodiment. Description of the basic configuration of FIG. 2 is omitted.

  FIG. 11 is a schematic view showing an example of a technique for local vapor deposition using the probe of the present invention.

  As shown in FIG. 11, the method of vapor deposition using the probe 207 includes a probe 207, a probe driving unit 208 for driving the probe, a power source 702, a wiring 703 connecting the probe 207 and the power source 702, and a vapor deposition material 1101. Has been.

  For example, C (carbon), Au (gold), Pt (platinum), or the like is used as the vapor deposition material 1101.

  FIG. 12 is an enlarged view of a portion composed of the probe 207, the vapor deposition material 1101, and the sample 102 in FIG.

First, the probe 207 with the vapor deposition material 1101 is arranged in the vicinity of a place where vapor deposition is desired. By applying a voltage with the power supply 702, the voltage is applied to the deposition material 1101 through the wiring 703 connecting the power supply 702 and the probe 207 to the probe 207.
By raising the voltage applied by the power source 702 to some extent, the temperature rises to a temperature at which the vapor deposition material 1101 is scattered. Thereby, it can vapor-deposit in the place which wants to perform vapor deposition, and can form the vapor deposition film 1201. FIG. Furthermore, since the sample 102 and the vapor deposition material 1101 are close to each other, local vapor deposition can be performed. Thereby, for example, vapor deposition can be performed in a region having a size corresponding to the vapor deposition material. Therefore, since only a small part of the sample is heated, the influence on the surroundings can be reduced.

  It can be applied to an apparatus having means for processing / observing / analyzing / processing in a vacuum using a charged particle beam.

The schematic diagram of the process in the charged particle beam apparatus of a comparative example. Sectional drawing which shows the structure of a focused ion beam processing observation apparatus. The schematic diagram of the processing method which collects a scattering material. The schematic diagram of the observation method which collects a scattering material. The apparatus block diagram for making a probe and the motion of a charged particle beam follow. The apparatus block diagram for cooling a probe. The apparatus block diagram for heating a probe. The schematic diagram which processes using the probe of another shape. The schematic diagram which performs the surface treatment of a probe. The apparatus block diagram for applying a voltage to a probe. The block diagram of the method of performing local vapor deposition. The expansion schematic diagram of the probe part of the method of performing local vapor deposition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Charged particle beam, ion beam, or electron beam 102 Sample 103 Scattering substance or contaminant 104 Observation surface 105 Processing area 201 Ion source or charged particle source 202 Ion gun chamber 203 Focusing lens 204 Deflector 205 Objective lens 206 Secondary Charged particle 207 Probe 208 Probe drive unit 209 Detector 210 Sample stage 211 Vacuum exhaust pump 212 Sample chamber 213 Deposition gas molecule supply unit 501 Electron gun chamber 502 Charged particle beam control mechanism 503 Control computer 504 Probe control mechanism 601 Refrigerant 602 Container 603 to be inserted Wiring 701 connecting the refrigerant and the probe Heater 702 Power supply 703 Wiring 801 Arbitrary shaped probe 1001 Earth 1101 Vapor deposition material 1201 Vapor deposition film

Claims (11)

A charged particle source;
An optical mechanism for irradiating the sample with charged particles generated from a charged particle source;
It has a detection mechanism that detects charged particles generated from the irradiated area of the sample by irradiation of charged particles,
An attachment mechanism that is formed so as to be disposed at a position corresponding to the irradiated region, and that attaches a part of the sample separated from the sample by the irradiation ,
A charged particle apparatus , wherein the adhesion mechanism moves following a position of a charged particle to be scanned on a sample .
2. The sample according to claim 1, wherein a part of the sample separated from the sample is different from the sample generated by the sample generated when scanning charged particles and the sample substance contained in the scattered substance or sample attached to the sample. A charged particle device comprising a substance.
The charged particle apparatus according to claim 1, wherein the adhesion mechanism includes a temperature control mechanism.
4. The charged particle apparatus according to claim 3 , wherein the temperature control mechanism includes a cooling mechanism.
4. The charged particle apparatus according to claim 3 , wherein the temperature control mechanism includes a heating mechanism.
4. The charged particle apparatus according to claim 3 , wherein the temperature control mechanism includes a cooling mechanism for lowering the temperature than before the temperature control operation and a heating mechanism for higher temperature than before the temperature control operation.
2. The attachment mechanism according to claim 1, wherein a surface area of a tip side region disposed in a region corresponding to an irradiation position of the charged particles is formed to be larger than a surface area of a support portion side region located closer to the support portion than the tip end region. Charged particle device characterized by being made.
The charged particle apparatus according to claim 1, wherein the adhesion mechanism includes a voltage application mechanism capable of applying a positive or negative voltage.
Irradiate the first region on the sample with charged particles generated from a charged particle source,
A first attachment step of attaching a portion of the sample separated from the first region by the irradiation to an attachment mechanism;
A first removal step of removing the adhered portion;
Irradiating a second area on the sample with charged particles,
A method of using a charged particle apparatus, comprising: a second attachment step of attaching a part of the sample separated from the second region by the irradiation to the attachment mechanism after the removal.
In Claim 9 , compared with said 1st removal step, controlling so that the temperature of the adhesion field where a part of said sample adheres in said adhesion mechanism in said 1st and 2nd adhesion steps becomes low. A method of using the charged particle device.
10. The control according to claim 9 , wherein a positive charge is applied to the attachment mechanism in the first attachment step and a negative charge is applied to the attachment mechanism in the first removal step. How to use a charged particle device.

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