JP5189916B2 - Fine sample processing method, observation method, and apparatus - Google Patents

Description

  The present invention relates to a fine sample processing method, observation method, and apparatus capable of obtaining a microscopic image of a fine sample and designating an arbitrary shape processing region on the sample to be processed with a focused ion beam based on the microscopic image. .

  With the progress of miniaturization of semiconductor structures, the needs for observation and analysis of the microstructure are increasing rapidly. In response to this, Scanning Transmission Electron Microscope (STEM) and Transmission Electron Microscope (TEM), which have high resolution and enable observation of minute samples, are used for observation and analysis of semiconductor microstructures. The frequency of doing is increasing. By the way, in the observation and analysis of the fine structure of a semiconductor using an electron microscope such as a scanning electron microscope (SEM), a scanning transmission electron microscope (STEM), or a transmission electron microscope (TEM), an observation point is previously extracted from the substrate. In addition, it is necessary to pre-process thinly to such an extent that an electron beam is transmitted as an observation sample.

  On the other hand, a focused ion beam (FIB) apparatus images secondary particles (for example, secondary electrons) generated from a sample by irradiation of the focused ion beam, and sets a processing region in the sample based on the image. Therefore, it is possible to produce a cross section for observation and a micro pillar at a desired location of a fine sample.

  For this reason, the focused ion beam apparatus is frequently used for observation and analysis of the fine structure of a semiconductor using an electron microscope, and is also used as a pretreatment processing apparatus for an observation sample using an electron microscope.

Japanese Patent Laid-Open No. 5-52721

  With the miniaturization of the semiconductor structure, the size of the characteristic part of the sample as the object of observation / analysis has become very small. Therefore, in the pretreatment processing of the observation sample by the focused ion beam apparatus, it is necessary to accurately position the processing position on the sample. The positioning of the processing position on the sample is performed by using a scanning ion microscope (SIM) image of the sample, and the processing region of the sample is designated (set) on the scanning ion microscope image of the sample. .

  Conventionally, the processing region of a sample using a scanning ion microscope image is specified as a beam irradiation position coordinate for each point on the sample included in the target region for a target region having an arbitrary shape on the scanning ion microscope image. Is done by doing. The designation of each point on the sample included in the target area is, for example, 4 in the upper / lower, left / right of the target area corresponding to the rectangular processed area when the processed area is rectangular. The boundary of the type was done by designating on the scanning ion microscope image.

  When further defining the scanning method of the focused ion beam in the processing region, that is, the method of moving the beam irradiation position in the processing region, the irradiation order of the beam irradiation position coordinates on the sample thus specified is further determined. It was necessary to specify.

  For this reason, with the miniaturization of the sample, it is possible to easily and quickly specify the arbitrary shape processing area for focused ion beam processing. It has become an important technical problem how to accurately and accurately set the) so as to remain in the center of the thin film.

  Therefore, according to the present invention, along with the miniaturization of the sample, designation of the thin film processing position and the micro pillar formation position can be performed easily and quickly with high positional accuracy, and the thin film processing and micro pillar processing of the sample can be performed accurately. An object of the present invention is to provide a fine sample processing method or the like that enables observation of the fine structure of the sample.

  In order to solve the above-described problems, the present invention provides a non-processed area (mask that does not perform a process using a focused ion beam for specifying an arbitrary shape process area for forming a thin film or a micropillar by using a focused ion beam process. It is characterized in that the designation of (region) is used.

  Therefore, in the present invention, it is possible to designate the arbitrarily shaped machining area on a scanning ion microscope image by combining the designation of the machining area by the focused ion beam and the designation of the non-machining area. And

  Further, in the present invention, the scanning ion microscope image corresponding to the region portion that does not overlap with the designated non-working region in the designated working region by the designation of the working region by the focused ion beam and the designation of the non-working region. By converting the above coordinates into beam irradiation position coordinates on the sample, machining data of an arbitrarily shaped machining area is created.

  According to the present invention, since an arbitrary shape processing region to be processed by the focused ion beam can be specified by a combination of the processing region and the non-processing region, the region shape pattern of the arbitrary shape processing region is complicated, for example, Even for a machining target such as a micro pillar, the machining data of the arbitrarily shaped machining region can be set easily and quickly.

  As a result, according to the present invention, there is an advantage that the efficiency of specifying the processing position and the processing throughput are greatly improved in processing of a fine sample using a focused ion beam.

  Embodiments of a fine sample processing method, observation method, and observation / processing apparatus of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a schematic configuration diagram of an example of a focused ion beam apparatus used in the present embodiment.

  The focused ion beam apparatus 1 includes an apparatus main body 10 including a sample chamber 11, an FIB column 12, and a detector 13, a deflection signal generation means 21, an XY independent zoom rate address conversion means 22, a detection signal processing means 23, and an image display. The control device 20 includes a control unit 24, the input device 30 includes a keyboard and a pointing device (for example, a mouse), and the display device 40 includes a display element such as an LCD.

  The FIB column 12 generates a focused ion beam 2 for irradiating the sample 50, and deflects the generated focused ion beam 2 by a deflector based on a deflection signal supplied from the deflection signal generating means 21. The sample 50 mounted on the sample stage or the sample holder is scanned and irradiated. The deflection signal generating means 21 is a beam scanning counter that generates a deflection address for designating the scanning position (beam irradiation position) of the focused ion beam 2, and a D / A conversion that generates an analog scanning signal corresponding to the deflection address. And a preamplifier for supplying a deflector in accordance with the analog scanning signal to the deflector in the FIB column 12.

  On the other hand, the secondary electrons 3 emitted from the sample 50 by scanning irradiation of the focused ion beam 2 are detected by the detector 13, and the detection signal is supplied to the detection signal processing means 23. In the detection signal processing means 23, the analog detection signal from the detector 13 is converted into a luminance voltage signal, and this luminance voltage signal is further converted into luminance data of a digital value, and an image provided in the image display control means 24 is provided. It is stored in the memory 25 as needed. A deflection address is supplied from the deflection signal generation unit 21 to the image display control unit 24. In the image display control unit 24, the luminance data from the detection signal processing unit 23 is stored in the image memory 25 in synchronization with the deflection address. Further, the image display control unit 24 generates a scanning ion microscope image based on the luminance data stored in the image memory 25 according to the scanning position of the focused ion beam 2 and outputs the image on the display device 40.

  The XY independent zoom rate address conversion unit 22 is supplied with a deflection address from the deflection signal generation unit 21 as in the image display control unit 24. The XY independent zoom rate address conversion unit 22 converts the deflection address based on the zoom rate set by a predetermined operation of the input device 30, generates a display address for zoom display, and the image display control unit 24. To supply. The image display control means 24 reads out necessary luminance data corresponding to this display address from the luminance data for each scanning position of the focused ion beam 2 stored in the image memory 25, and a sample 50 made of a scanning ion microscope image. Sample images (including zoom images) are generated and displayed on the display device 40. The XY independent zoom rate address conversion means 22 can change the display magnification of the scanning ion microscope image of the sample 50 on the screen of the display device 40 independently of the X axis and the Y axis.

  FIG. 2 shows an embodiment of the circuit configuration around the image memory in the image control means.

  The image memory 25 is constituted by a dual port memory 25 ′, stores luminance data supplied as a secondary particle luminance signal from the detection signal processing means 23, and a display control circuit 26 provided in the image display control means 24. The luminance data can be output asynchronously. For this reason, the image memory 25 has a luminance data input port Data-in and a luminance data output port Data-out independently, and designates a storage address (write address) of the input luminance data from the detection signal processing means 23. And an output address port Address-out for designating a storage address (read address) of luminance data to be output to the display control circuit 26.

  The shift register 27x moves the horizontal slide bar used when the display target portion of the scanning ion microscope image is moved laterally on a sample processing editing screen or the like displayed on the display screen of the display device 40 by OSD (On Screen Display). A value sx corresponding to the quantity is output. The adder circuit 28x receives the value sx of the shift register 27x and the X-axis deflection address dx from the deflection signal generating means 21, and adds and outputs both.

  The shift register 27y is a value corresponding to the amount of movement of the vertical slide bar used when the display target portion of the scanning ion microscope image is moved up and down on the sample edit screen or the like displayed on the display screen of the display device 40. sy is output. The adding circuit 28y receives the value sy of the shift register 27y and the Y-axis deflection address dy from the deflection signal generating means 21, and adds and outputs both.

  Thus, the beam irradiation position on the sample 50 mounted on the sample holder is stored in the image memory 25 in accordance with the observation visual field on the sample 50, that is, the horizontal movement or vertical movement of the display target portion of the scanning ion microscope image. It can be made to correspond to an address.

  In addition, the outputs sx + dx and sy + dy of the adder circuits 28x and 28y are input to the barrel shift circuits 29x and 29y, respectively. The zoom rate Zoom-x in the X-axis direction is input as a shift bit signal to the barrel shift circuit 29x, and the zoom rate Zoom-y in the Y-axis direction is input as a shift bit signal to the barrel shift circuit 29y. As a result, the outputs sx + dx and sy + dy of the adder circuits 28x and 28y are shifted from the barrel shift circuits 29x and 29y according to the zoom rates Zoom-x and Zoom-y, respectively, and are input to the input address port Address-in of the image memory 25. It is supplied as a storage address (write address). Thus, the zoom ratio Zoom and the address of the image memory 25 are converted, and even when zoom observation is performed, the beam irradiation position on the sample 50 can be stored in the image memory 25 in correspondence with the memory address. It can be done.

  On the other hand, the display control circuit 26 is connected to an XY independent zoom rate address conversion unit 22, an OSD control circuit (not shown) included in the image display control unit 24, and the like. The display control circuit 26 converts the display address supplied from the XY independent zoom rate address conversion means 22 into a storage address (read address) of the image memory 25 in which the luminance data of the corresponding part is stored, and This is supplied to the input address port Address-out of the memory 25. Further, the display control circuit 26 responds to the supply of the storage address (read address) to the input address port Address-out, luminance data output from the output port Data-out of the image memory 25, and OSD (not shown). The OSD display data including the GUI supplied from the control circuit is taken in, and for example, display data on a processing edit screen or the like is generated. The generated display data is supplied from the display control circuit 26 to the display device 40 and displayed on the screen.

  FIG. 3 is a flowchart showing a processing procedure of a fine sample using the focused ion beam apparatus of the present embodiment.

  First, a target area is created in the vicinity of a defective portion in the sample 50, and a processing pattern of the created target area is designated as a mask mode (non-processed area mode) to make this target area a non-processed area (step S100). ).

  Next, create the target area including the surrounding area so that the target area (non-processed area) with the mask mode specified can be sampled by thinning and micro-pillars. A non-mask mode (processing area mode) is designated, and this target area is set as a processing area (step S200).

  Next, a scanning mode (scanning method) of the focused ion beam irradiated when processing the specified processing region is specified (step S300). In specifying the scanning method of the focused ion beam when processing this processing region, the boundary surface of the overlapping portion of the non-processing region specified in the mask mode (non-processing region) and the processing region including the periphery thereof By specifying a scanning mode in which the part is processed by the last irradiation of the focused ion beam, the influence on the interface part that occurred in the processing part by the previous beam irradiation is suppressed. The finishing of the boundary surface can be improved.

Next, processing data of an arbitrary shape processing region to be processed by actual irradiation of the focused ion beam 2 is created based on the specified non-processing region and processing region and the specified focused ion beam scanning method (step). S400).
Then, based on the created processing data of the arbitrary shape processing region, the focused ion beam is irradiated for a predetermined time in a predetermined order at each irradiation position on the sample 50 included in the arbitrary shape processing region. Thus, the processing of the sample 50 is started (step S500). When the processing of the sample 50 based on the processing data of the arbitrary shape processing region is completed, the series of processing is ended (step S600).

  As described above, in the fine sample processing method according to the present embodiment, designation of an arbitrary shape processing region to be processed by actual irradiation of the focused ion beam 2 is not performed in order to form a thin film or a micro pillar on the sample. It is characterized in that it can be performed by combining (synthesizing) the processing region and the processing region including the peripheral portion of the non-processing region.

  Next, in the processing procedure of the fine sample 50 using the focused ion beam apparatus 1 described above, the non-processed area specified in step S100, the specified process area specified in step S200, and the process shown in step S300 are performed. A specific example of specifying the scanning mode of the focused ion beam 2 will be described.

  FIG. 4 shows an embodiment of a processing edit screen when creating a processing pattern of an arbitrary shape processing region.

  In FIG. 4, FIG. 4 (a) shows an initial machining edit screen before designation of a non-machining area and a machining area, and FIG. 4 (b) shows a case where a non-machining area or a target area as a machining area is designated. FIG. 4C shows a machining edit screen when a machining pattern of an arbitrarily shaped machining area is created.

  The process edit screen 400 is displayed on the display screen of the display device 40 as an OSD as a GUI (Graphical User Interface) for the user to specify a process area.

  The processing edit screen 400 displays a scanning ion microscope image 60 of a desired portion of the sample 50 in order to designate the target region 70, and the sample 50 displayed on the processing target display unit 410. On the scanning ion microscope image 60 of the desired portion, various operation buttons 420 for specifying the target region 70 are provided.

  Among these various operation buttons 420, an object to be operated is selected from the screen of the processing target display unit 410, or the scanning ion microscope image 60 displayed on the screen of the processing target display unit 410 is zoomed. An operation button 421 used when performing the operation, an operation button 422 used when designating a shape state such as a concave shape or a convex shape for the selected target region, and a rectangle, a sector, a circle, a straight line, A creation button 423 used when creating a predetermined target area 70 such as a curve is included.

  FIG. 4B shows a defective portion or the like that appears in a predetermined portion on the scanning ion microscope image 60 of the sample 50 displayed on the processing target display unit 410 on the processing editing screen 400 in FIG. The case where the various operation buttons 420 described above are appropriately operated with respect to the attention site (observation site) 62 using the pointing device of the input device 30 and the rectangular target region 70 is specified by being superimposed is shown.

  Next, the processing area setting screen 500 shown in FIG. 5 is used to specify the processing area 80 or the non-processing area 90 for the target area 70 with the target area 70 selected using a pointing device. ing.

  FIG. 5 shows an example of a processing condition setting screen for specifying a processing region or a non-processing region for a selected target region.

  Note that the processing condition setting screen 500 and the processing editing screen 400 are displayed on the display screen of the display device 40 together as, for example, the processing editing screen 400 and the processing condition setting screen 500 as individual windows. The processing condition setting screen 500 may be popped up on the processing editing screen 400 based on a predetermined operation specifying a specific target area 70 on the processing editing screen 400. The specific display method of both screens is not limited.

  The machining condition setting screen 500 includes various machining condition setting fields 510. In these various processing condition setting fields 510, a scanning interval setting field 511 for setting a time interval (Interval) between individual scans, irradiation of a focused ion beam per point of irradiation position coordinates. A beam stay time setting field 512 for setting a time (Dwell Time), a processing type setting field 513 for selecting whether to subject the target area 70 to surface processing (fill) or line processing along a boundary line. A beam for processing the mask mode setting field 514 for selecting whether the target region 70 is a processing region 80 processed by a focused ion beam or a non-processing region (Mask mode) 90 that is not processed. A scan mode setting field 515 for selecting a scan mode (Scan) is included.

  In the example shown in the figure, for this target area 70, the surface type of the target area 70 is designated by checking the check box in the processing type setting field 513, and the mask mode is turned on by checking the check box in the mask mode setting field 514. Thus, a non-processed region 90 that is not processed by the focused ion beam is formed (FIG. 2, step S100).

  In FIG. 4C, after that, various operation buttons 420 are appropriately operated using the pointing device of the input device 30 again on the process editing screen 400, and the target region 71 is specified by overlapping the target region 70. Shows the case.

  In the case of the present embodiment, in the state where the target area 71 is selected using a pointing device, the processing type setting column 513 is checked for the target area 71 on the processing condition setting screen 500 shown in FIG. The box is checked to specify surface processing of the target region 71, and the check box of the mask mode setting column 514 is unchecked to turn off the mask mode, and the processing region 80 is processed by the focused ion beam (FIG. 2). Step S200).

  As a result, the control device 20 uses the OSD control circuit in the image display control unit 24 and the like for a predetermined portion of the scanning ion microscope image 60 of the sample 50 displayed on the processing target display unit 410 on the processing editing screen 400. Arbitrary shape processing for actually processing, by the focused ion beam 2, two region portions 80a and 80b that do not overlap with the target region 70 specified as the non-processing region 90 in the target region 71 specified as the processing region 80 The area is designated as two actual machining areas 100 a and 100 b grouped as the area 100. The control device 20 acquires position coordinates on the sample 50 corresponding to the two actual processing regions 100a and 100b as beam irradiation position coordinates on the sample 50.

  Furthermore, both the non-processing target area 90 and the processing target area 80 can be specified by a desired figure having the attention site 62 such as a defective part at the common center of the areas 90 and 80. The processing regions 100a and 100b can be easily set so as to be positioned symmetrically with respect to the portion to be observed, that is, the target region 62.

  As described above, in the present embodiment, designation of the arbitrarily shaped processing region 100 on the sample 50 is first performed on the scanning ion microscope image 60 with the target regions 70 and 71 having a shape corresponding to the shape of the non-processing region or the processing region. It can be performed easily and quickly by specifying as the non-processed area 90 or the processed area 80 for each of the target areas 70 and 71 specified in this way. Also, the creation of the machining data of the arbitrary shape machining area 100 is not overlapped with the designated non-machining area 70 in the designated machining area 71 by the designation of the machining area 80 and the designation of the non-machining area 90. By converting the coordinates on the scanning ion microscope image 60 corresponding to the region portion 100 into the beam irradiation position coordinates on the sample 50, it can be performed easily and quickly.

  In addition, in this embodiment, a beam scan method (scan data creation method) is further selected by the beam scan method setting field 515 on the processing condition setting screen 500.

  In the beam scanning method setting field 515, as shown in FIG. 5, buttons 515-1 to 515-4 for designating the respective left, right, upper and lower scanning directions of the area from the upper and lower sides of the area toward the center. Button 515-5 for designating the scanning direction of the button 515-6 for designating the scanning direction from the left and right sides of the region toward the center, and a button 515 for designating the scanning direction from the boundary surface side of the rectangular region to the inside. -7, a button 515-8 for designating the scanning direction from the boundary surface side to the inward side of the circular region, a button 515-9 for designating the scanning direction from the inner side of the circular region to the boundary surface side, a rectangle A button 515-10 for designating a scanning direction from the inner side of the region toward the boundary surface is provided.

  In the case of the present embodiment, the scanning direction mode from the upper and lower sides of the region toward the center is set as the beam scanning method by operating the button 515-5 for the target region 71 designated as the processing region ( FIG. 2, step S300).

  As a result, the control device 20 receives these operation instructions via the OSD control circuit or the like in the image display control means 24, and the direction along the upper and lower boundary surfaces of the target area 71 as conceptually shown in FIG. Scan of the irradiation position coordinates in which the scanning position is sequentially displaced in the direction of arrow P from the upper and lower sides of the target area 71 toward the corresponding upper and lower boundary side of the target area 70 as the non-processed area 90 Arbitrary shape machining data for the arbitrary shape machining region 100 (100a, 100b) including data is created.

FIG. 6 is a conceptual explanatory diagram regarding the arbitrary shape machining data created by the control device.
In this case, with respect to the actual processing region 100a positioned above the target region 70 designated as the non-processing region 90, the scanning beam 64 along the upper or lower boundary surface from one side of the left and right boundary surfaces to the other side. Including the irradiation position on the sample and its scan data, which are sequentially shifted from the upper boundary surface side opposite to the non-processing region 90 side toward the lower boundary surface side on the non-processing region 90 side. Create custom machining data.

  Similarly, for the actual processing region 100b positioned below the target region 70 designated as the non-processing region 90, the scanning beam 64 along the upper or lower boundary surface from one side of the left and right boundary surfaces to the other side. Including the irradiation position on the sample and its scan data, which are sequentially shifted from the lower boundary surface side opposite to the non-processing region 90 side toward the upper boundary surface side on the non-processing region 90 side. Create custom machining data.

  In the illustrated example, the scanning beam 64-1 is irradiated along the boundary surface opposite to the target region 70 side of the region 100a of the arbitrary shape processing region 100, and then the target region 70 side of the region 100b is defined. Irradiation of the scanning beam 64-2 along the opposite boundary surface is performed, and then irradiation of the scanning beam 64-3 on the inner portion of the scanning beam 64-1 irradiated before the region 100a is performed. The scanning beam 64-4 is irradiated on the inner part of the scanning beam 64-2 irradiated before the region 100b. For example, the region 100a and the region 100b are alternately shifted to the inner side in each region, and the scanning beam is scanned. It is the structure which performs 64 irradiation.

  Next, similarly, a case where a micro pillar is manufactured on the sample surface of the sample 50 will be described.

  FIG. 7 is a conceptual explanatory diagram regarding arbitrary shape machining data when the micro pillar created by the control device is produced.

  Also in this case, first, the pointing device of the input device 30 is used for the part 62 for producing the micro pillar on the scanning ion microscope image 60 of the sample 50 displayed on the processing target display unit 410 on the processing editing screen 400. By appropriately operating the various operation buttons 420 described above, a rectangular target region 70 that matches the pillar cross-sectional area is specified, and surface processing is specified for the target region 70 using the processing condition setting screen 500, The mask mode is turned on, and the non-processed region 90 that is not processed by the focused ion beam is set (FIG. 2, step S100).

  Next, a target region 71 that is concentric with the target region 70 and has a larger area than the target region 70 on the scanning ion microscope image 60 of the sample 50 displayed on the processing target display unit 410 on the processing edit screen 400. For the target region 71, surface processing is specified using the processing condition setting screen 500, the mask mode is turned off, and the processing region 80 is processed by the focused ion beam (FIG. 2, step S200). ).

  As a result, the control device 20 uses the focused ion beam 2 to convert a rectangular frame-shaped region portion 80 that does not overlap with the target region 70 specified as the non-processing region 90 in the target region 71 specified as the processing region 80. Designation is made as a grouped arbitrary shape machining region 100 to be actually machined. The control device 20 acquires position coordinates on the sample 50 corresponding to the two actual processing regions 100 as beam irradiation position coordinates on the sample 50.

  Further, by operating the button 515-7 for the target region 71 designated as the processing region by the beam scanning method setting field 515 of the processing condition setting screen 500, the beam scanning method is selected from the boundary surface side of the rectangular region. An inward scanning direction mode is set (FIG. 2, step S300).

  In this case, as shown in FIG. 7, the rectangular scanning beam 64 along the boundary line of the rectangular frame-shaped arbitrary processing region 100 surrounding the target region 70 designated as the non-processing region 90 is not processed. The irradiation position on the sample and the scan data thereof are sequentially shifted from the boundary surface side opposite to the region 90 side toward the upper boundary surface side of the non-working region 90 side while reducing the size of the region 90 in a similar manner. Creates the desired shape machining data including.

  Thereby, in the processing of the micro pillar using the focused ion beam, conventionally, a plurality of (for example, four) setting of a rectangular frame-like arbitrary shape processing region surrounding the micro pillar is set around the cutting position. The rectangular processing regions are designated and arranged, and the focused ion beam processing must be performed for each rectangular processing region. However, by specifying one processing region and one non-processing region, As shown in FIG. 7, the setting of a rectangular frame-shaped arbitrary shape processing region surrounding the micro pillar for processing the micro pillar is performed by combining (combining) the one processing region and one non-processing region as shown in FIG. It can be set easily and quickly. Further, since the side surface of the micro pillar is finally formed by the rectangular scanning beam 64, the processing finish of the side surface of the micro pillar can be improved.

  As described above, in this embodiment, when a certain target region 71 is designated as the processing region 80, processing conditions including beam scanning of the focused ion beam in the processing region 71 can be arbitrarily set. In addition, the setting of the beam scanning of the focused ion beam in the machining data of the arbitrary shape machining area at that time is performed by the focused ion beam beam scanning along the boundary surface of the arbitrary shape machining area. Scanning method that sequentially moves from one side to the other boundary surface side, beam scanning of a focused ion beam that is similar to the shape of the arbitrary shape processing region is the inner side of the arbitrary shape processing region or the boundary side or inward from the boundary side It can be performed easily and quickly when designating the processing region in accordance with the shape of the processing target such as a thin film or a micro-pillar, such as a scanning method that sequentially expands or contracts toward the surface.

  In the above description, the non-processing area 90 and the processing area 80 are designated by the rectangular target areas 70 and 71. However, the target areas 70 and 71 are circular, fan-shaped, and trapezoidal according to the arbitrary-shaped processing area to be processed. For example, a target area prepared in advance other than a rectangular shape may be specified, and the target areas 70 and 71 to be specified may have different shapes. In the case where the shapes of the non-processed region 90 and the processed region 80 are different, the setting of the beam scanning method improves the processing finish of the boundary surface to which the beam is finally irradiated. The scanning beam 64 along the boundary surface on the destination side in the scanning direction is automatically specified based on the operated buttons 515-1 to 515-10.

  Further, in the above description, the example in which one target region 70 as the non-working region 90 and one target region 71 as the processing region 80 are specified has been described. However, the non-working region 90 or the processing region 80 is a plurality of target regions. It does not preclude designation by a combination of 70 or a combination of a plurality of target areas 71, and even in such a case, since it can be performed by a combination of a machining area and a non-machining area, an arbitrarily shaped machining area is set. Can be done easily and quickly.

  That is, according to the present embodiment, even in the processing of an arbitrary shape processing region, the processing of the arbitrary shape processing region can be performed by making full use of the mask processing pattern based on the designation of the non-processing region and various focused ion beam scanning methods. Therefore, even a material that is particularly vulnerable to electron beam irradiation can be processed with high positional accuracy, a highly accurate fine sample can be manufactured, and high-resolution observation based on this fine sample by an electron microscope is possible.

<Second Embodiment>
In the present embodiment, an FIB-SEM apparatus 1 ′ as a composite apparatus in which an FIB column 12 and a scanning electron microscope column 14 are mounted on the same sample chamber 11 of the apparatus main body 10 is used. A case of processing will be described.

  In the description, the same or corresponding components as those of the focused ion beam apparatus 1 described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 8 is a schematic configuration diagram of an example of the FIB-SEM apparatus used in the present embodiment.

  The FIB-SEM apparatus 1 ′ includes an apparatus main body 10 including a sample chamber 11, an FIB column 12, an electron beam column 14, a detector 13, a deposition gun 15, and a microprobe 16, a control apparatus 20, a keyboard, and a pointing device. The input device 30 includes a device (for example, a mouse) and the like, and the display device 40 includes a display element such as an LCD.

In connection with the focused ion beam processing, the control device 20 includes a deflection signal generation means, an XY independent zoom rate address conversion means, a detection signal processing means, and an image display control means (not shown). It is the same as that used in a scanning electron microscope (SEM), and the sample 50 is scanned with the electron beam 4 while being focused on the sample 50. The detector 13 detects secondary electrons emitted from the sample 50 by scanning irradiation with the focused ion beam 2 and the electron beam 4. The deposition gun 15 emits a processing gas when a protective film is formed on the sample 50 or when a thin film sample or micro pillar manufactured by focused ion beam processing is fixed to another object. The microprobe 16 is for carrying a thin film sample or micropillar produced by a focused ion beam. A sample stage 17 for holding and moving the sample 50 is mounted in the sample chamber 11. In addition to the sample 50, the sample stage 17 is also equipped with a thin film carrier 18 for mounting a sampled thin film sample or a micro sample such as a micro pillar.

  The FIB-SEM apparatus 1 ′ configured as described above controls and controls the secondary electrons generated by the focused ion beam 2 by the detector 13 when the focused ion beam 2 is irradiated onto the sample 50 from the FIB column 12. When the scanning ion microscope image is displayed on the screen of the display device 40 by the image control means of the apparatus 20 and the electron beam 4 is irradiated onto the sample 50 from the electron beam column 14, secondary electrons by the electron beam 4 are emitted. Is detected by the detector 13, and the scanning electron microscope image is displayed on the screen of the display device 40 by the image control means of the control device 20. Switching between the focused ion beam 2 and the electron beam 4 is performed by switching the scan control and the blanking control as desired according to a timing command from the control device 20.

  Also in the FIB-SEM apparatus 1 ′ configured as described above, the image is displayed on the display device 40 and displayed on the image monitor window 600 that can switch and display the scanning ion microscope image and the scanning electron microscope image, as shown in FIGS. As described above, in the scanning ion microscope image or the scanning electron microscope image, the arbitrary shape processing region 100 can be set easily and quickly in the same manner as in the focused ion beam apparatus according to the first embodiment.

  FIG. 9 is a conceptual explanatory diagram regarding arbitrary shape processing data when a thin film is formed on an image monitor window.

  FIG. 10 is a conceptual explanatory diagram regarding arbitrary shape machining data when a micro pillar is manufactured on an image monitor window.

  Next, a method for extracting (microsampling) the micro sample 53 including the observation site (target site) 51 in the sample 50 using the FIB-SEM apparatus 1 ′ will be described.

  FIG. 11 shows a processing procedure for extracting a fine sample.

  First, on the above-described image monitor window, an irradiation region 81 for forming a deposition film 52 by FIB induced deposition (gas assist deposition) on a target region 51 of the sample 50 (see FIG. 11 (1)). Is specified. In addition, the focused ion beam 2 was locally irradiated to the irradiation region 81 while releasing tungsten hexacarbonyl gas from the deposition gun 15 toward the irradiation region 81, and the gas was constituted by irradiation of the focused ion beam 2. The metal is decomposed and deposited on the processing region 81 to form a deposition film (deposition film) 52 (see FIG. 11 (2)).

  Next, in order to perform drilling of the sample 50 around the region of interest 51, first, the deposition film 52 portion is designated as the non-working region 90 on the image monitor window, and the deposition film (deposition film) 52 portion is designated. In addition, a processing region 80 larger than the deposition film (deposition film) 52 portion centered on the target region 51 is specified, and the focused ion beam 2 is scanned and irradiated to an arbitrary shape processing region 100 formed by a combination of both regions 80 and 90. Then, the groove film processing around the deposition film 52 is performed. After the groove film processing, the sample 50 is tilted, and similarly, on the image monitor window, the boundary surface of both the regions 80 and 90 extending in the depth direction of the sample 50 is a non-processed region (not shown) on the groove opening side. ) And a processing region (not shown) on the groove bottom side, and a focused ion beam 2 is scanned and irradiated to an arbitrary shape processing region (not shown) consisting of a combination of both regions, and the groove bottom portion on the boundary surface Perform the process of slitting the side. By this slitting process, a cantilever-shaped fine sample 53 including the target region 51 protected by the deposition film 52 is produced (see FIG. 11 (3)).

  Then, the tilted sample 50 is returned to the original state, the tip of the microprobe 16 is positioned on the cantilever-shaped fine sample 53, and the tip of the microprobe 16 and the fine sample 53 are bonded on the image monitor window. The irradiation region 81 for forming the deposition film 52 for this purpose is designated. Then, the focused ion beam 2 is locally irradiated to the irradiation region 81 while releasing tungsten hexacarbonyl gas from the deposition gun 58 toward the irradiation region 81, and the tip of the microprobe 16 and the fine sample 53 are irradiated by the deposition film 52. Are bonded together (see FIG. 11 (4)).

  Next, a processing region 80 is designated on the image monitor window 600 at a portion where the cantilever-shaped fine sample 53 is connected to the sample 50, and a focused ion beam is formed on the arbitrary shape processing region 100 including the processing region 80. 2 is scanned and the fine sample 53 is separated from the sample 50 (see FIG. 11 (5)). Then, the microprobe 16 is raised, and a fine sample 53 containing the target site 51 is extracted.

  Next, the sample stage 17 is moved so that the thin film carrier 18 comes to the FIB optical axis (see FIG. 11 (6)). Then, the microprobe 16 is lowered, the fine sample 53 is brought into contact with the thin film carrier 18, and a deposition film 52 for bonding the fine sample 53 and the thin film carrier 18 is formed on the image monitor window. The irradiation area 81 is designated. Then, the focused ion beam 2 is locally irradiated onto the irradiation region 81 while releasing tungsten hexacarbonyl gas from the deposition gun 58 toward the irradiation region 81, and the thin film carrier 18 and the fine sample 53 are formed by the deposition film 52. Are bonded (see FIG. 11 (7)).

  Thereafter, on the image monitor window, an irradiation region 81 is designated at the bonding portion between the tip of the microprobe 16 and the fine sample 53, the focused ion beam 2 is locally irradiated on the irradiation region 81, and the deposition film 52 is removed. The sample 53 and the microprobe 16 are separated (see FIG. 11 (8)).

  Through the above steps, the fine sample 53 containing the target region 51 was sampled from the sample 50 and transferred onto the thin film carrier 18.

  Next, with reference to FIGS. 12 and 13, the case where the fine sample 53 is subjected to double-sided cross section extraction of the target portion 51 of the fine sample 53 using mask processing and a section view having an arbitrary shape will be described. In FIG. 12, FIG. 12 (5) shows the fine sample 53 shown in FIG. 12 (1) from the perspective, and FIG. 12 (6) shows the fine sample shown in FIG. 12 (3). The plane of the sample 53 is viewed from the perspective direction.

  FIG. 12 is an explanatory diagram of a processing procedure for processing a thin film from a sampled fine sample.

  FIG. 13 is a processing flowchart for processing a thin film from a sampled fine sample.

  First, mask processing with an arbitrarily processed shape is performed on the fine sample 53 (step S1100), and a cross section on both sides (step S1200) is performed using a section view (see FIGS. 12 (2) and 12 (3)).

  The target portion 51 is assumed to be, for example, a capacitor 54 of a semiconductor sample. When a cross section in which a capacitor row (not shown) opposed to each other disappears is determined by a section view of the image monitor window, the processing ends.

  The surface on the back surface side (the side close to the thin film carrier 18) of the fine sample 53 has a rectangular processed region 80 and a rectangular non-processed region 90 with a thickness of 0.3 μm of the portion including the capacitor 54 as a guide. The arbitrary processed shape region 100 based on the combination of the two specified regions 80 and 90 is processed, and the fine sample 53 is thinned.

  Next, for the purpose of forming the central cross section of the target capacitor 54, the focused ion beam processing is performed in the direction of gradually reducing the film thickness of the thin film (see FIG. 12 (2)). In that case, a scanning electron microscope provided with an electron beam column 14 is used under the condition of an acceleration voltage of 30 kV, and the end point of the processing is determined while checking the cross-sectional information with a scanning electron microscope image displayed in the section view ( Steps S1300 to S1600).

  For the capacitor 54 portion of the fine sample 53, a low dielectric constant material such as an organic polymer or organic silica glass, for example, a so-called Low-K material, which is a material that is weak against irradiation with the electron beam 4, is used. Since the 30 kV electron beam 4 passes through the thin film sample 55, energy loss inside the thin film sample 55 is small, and damage and deformation of the thin film sample 55 can be minimized.

  Thereafter, the fine sample 53 is rotated together with the thin film carrier 18, that is, the sample stage 17 is rotated 180 degrees in the horizontal plane (step S1700), and the back surface (in this case, the side away from the thin film carrier 18) is also as described above. Processing is performed in the same manner (steps S1300 to S1600), and finally a thin film sample 55 having a thickness of 60 nm is obtained by cutting out the center of the capacitor 54 (see FIG. 12C).

  In this way, after thin film processing using the section view, the final thin film finishing processing is performed while performing cross-sectional confirmation by scanning electron microscopy using a high acceleration electron beam, so that damage or deformation can be caused by electron beam irradiation. Even for materials that are susceptible to damage, thin film processing with minimal damage and deformation and high processing position accuracy is possible. The processed thin film sample 55 is transferred together with the thin film carrier 18 to a holder of a high acceleration scanning transmission electron microscope or a transmission electron microscope, and image observation with high resolution is performed.

  As described above, according to this embodiment, when a fine sample is processed, the fine sample is observed with a high acceleration electron beam, thereby enabling observation with reduced sample damage, and an observation image (sample image) using the electron beam. By using together, it becomes possible to process a focused ion beam into a thin and highly accurate thin film sample, and to perform high-resolution observation with an electron microscope.

<Third Embodiment>
The third embodiment is an example in which a cross-section monitor during thin film / micropillar finishing processing is implemented by a scanning transmission electron microscope image.

  FIG. 14 is a schematic configuration diagram of an example of the FIB-SEM apparatus used in the present embodiment.

  In the description, the same or corresponding components as those of the FIB-SEM apparatus 1 ′ described in the second embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The FIB-SEM apparatus 1 ″ used in the present embodiment has a configuration in which a side entry stage 170 and a STEM detector 19 are newly added to and mounted on the FIB-SEM apparatus 1 ′ shown in FIG. It has become.

  The side entry stage 170 extends in the sample chamber 11 so as to be movable in the lateral direction, and is provided with a holder 171 that can be rotated around its own axis and mounted on the holder 171 so that its own axis is perpendicular to the holder 171. The configuration includes a needle-shaped carrier 173 that can be rotated by 172.

  Next, a method for extracting (microsampling) the micro sample 53 including the observation site (target site) 51 in the sample 50 using the FIB-SEM apparatus 1 ″ will be described.

  FIG. 15 is an explanatory diagram of a thin film processing procedure according to this embodiment.

  First, on the above-described image monitor window, a deposition film 52 by FIB induced deposition (gas assist deposition) is formed on the target portion 51 of the sample 50 (see FIG. 15 (1)) (FIG. 15 (2)). )reference).

  Next, in order to drill a hole in the sample 50 around the site of interest 51, first, the deposition film 52 portion and the deposition film 52 portion are connected to the sample 50 portion around the processing region on the image monitor window. The connecting portion to be designated is designated as a non-working region 90, 90, and a designated processing region 80 including the deposition film (deposited film) 52 portion, which is larger than the non-working region 90, 90 portion centered on the target portion 51, A focused ion beam 2 is scanned and irradiated to an arbitrarily shaped processing region 100 formed by a combination of both regions 80, 90, 90, and groove film processing around the non-processing regions 90, 90 is performed. After the groove film processing, the sample 50 is tilted, and similarly, on the image monitor window, the boundary surface of both the regions 80 and 90 extending in the depth direction of the sample 50 is a non-processed region (not shown) on the groove opening side. ) And a processing region (not shown) on the groove bottom side, and a focused ion beam 2 is scanned and irradiated to an arbitrary shape processing region (not shown) consisting of a combination of both regions, and the groove bottom portion on the boundary surface Perform the process of slitting the side. By this slitting process, a cantilever-supported fine sample 53 including the target region 51 protected by the deposition film 52 is produced (see FIG. 15 (3)).

  Then, the tilted sample 50 is returned to its original state, the tip of the microprobe 16 is positioned on the cantilever-shaped fine sample 53, and the tip of the microprobe 16 and the fine sample 53 are bonded by the deposition film 52. (Refer to FIG. 15 (4)).

  Next, the focused ion beam 2 is scanned and irradiated to the connection portion of the fine sample 53 with the sample 50, and the fine sample 53 is separated from the sample 50 (see FIG. 15 (5)). Then, the microprobe 16 is raised, and a fine sample 53 containing the target site 51 is extracted.

  Next, the sample stage 17 is moved so that the needle-shaped carrier 173 of the side entry stage 170 comes to the FIB optical axis. Then, the microprobe 16 is lowered to bring the fine sample 53 into contact with the needle-shaped carrier 173 (see FIG. 15 (6)).

  Then, the needle-shaped carrier 173 and the fine sample 53 are bonded by the deposition film 52 by FIB induced deposition (gas assist deposition) (see FIG. 15 (7)).

  Thereafter, the focused ion beam 2 is locally irradiated on the irradiation region 81 at the bonding portion between the tip of the microprobe 16 and the fine sample 53 to remove the deposition film 52, and the fine sample 53 and the microprobe 16 are separated (FIG. 15). (See (8)).

  Thereafter, when the processing procedure for processing the thin film sample 55 from the sampled fine sample 53 described in FIG. 12 is performed, the fine sample 53 needs to be rotated. In this embodiment, the needle-shaped carrier 8 is used. The thin film sample 55 is processed while the holder 171 is moved or rotated in the sample chamber 11 as necessary. Note that the present embodiment is different in that the STEM detector 19 is used for observing the cross-sectional structure with an electron beam during the finishing process.

  According to the present embodiment, the fine sample 53 on which the processed thin film sample 55 is formed is mounted on the holder 171 of the side entry stage 170, and the holder 171 is removed and the holder 171 together with a transmission electron microscope or scanning transmission electron. By moving to a microscope dedicated machine, it becomes possible to observe an image with a higher resolution. Furthermore, in this embodiment, since there is no need to attach or detach the thin sample 53 to and from the thin film carrier 18 in the mounted state, there is a low risk that the sample will be damaged or lost during work, and a plurality of samples can be secured. It is suitable for difficult defect analysis.

It is a schematic block diagram of one Example of the focused ion beam apparatus used by this Embodiment. 1 shows an embodiment of a circuit configuration around an image memory in an image control means. It is the flowchart which showed the processing procedure of the fine sample using the focused ion beam apparatus of a present Example. An example of the process edit screen when designating the process pattern of an arbitrary-shaped process area is shown. An example of the processing condition setting screen for designating the processing region or the non-processing region for the selected target region is shown. It is a conceptual explanatory drawing regarding arbitrary shape process data. It is a conceptual explanatory drawing regarding the arbitrary shape process data in the case of producing a micro pillar. It is a schematic block diagram of one Example of the FIB-SEM apparatus used by 2nd Embodiment. It is a conceptual explanatory drawing regarding the arbitrary shape process data in the case of producing a thin film on an image monitor window. It is a conceptual explanatory drawing regarding arbitrary shape processing data in the case of producing a micro pillar on an image monitor window. A processing procedure for extracting a fine sample is shown. It is explanatory drawing of the process sequence which processes a thin film from the sampled fine sample. It is a process flowchart which processes a thin film from the sampled fine sample. It is a schematic block diagram of one Example of the FIB-SEM apparatus used by 3rd Embodiment. It is explanatory drawing of the thin film processing procedure by this Embodiment.

Explanation of symbols

1 Focused ion beam device, 1 'FIB-SEM device, 2 Focused ion beam,
3 secondary electrons, 4 electron beams, 10 device body, 11 sample chamber,
12 FIB columns, 13 detectors, 14 electron beam columns,
15 deposition gun, 16 microprobe, 17 sample stage,
170 side entry stage, 171 holder, 172 rotation mechanism,
173 needle type carrier, 18 thin film carrier, 19 STEM detector,
20 control device, 21 deflection signal generating means,
22 XY independent zoom rate address conversion means, 23 detection signal processing means,
24 image display control means, 25 image memory, 25 'dual port memory,
26 display control circuit, 27 shift register, 28 addition circuit,
29 barrel shift circuit, 30 input device, 40 display device, 50 samples,
51 region of interest, 52 deposition film, 53 fine sample, 54 capacitor,
55 thin film sample, 60 scanning ion microscope image, 62 defective part,
64 scanning beam, 70, 71 target area, 80 machining area,
90 non-machining area, 100 arbitrary shape machining area, 400 machining edit screen,
410 processing object display section, 420 operation buttons,
421, 422, 423 operation buttons,
440 defective part, 451 target area (non-working area),
452 Target area (machining area), 500 Machining condition setting screen,
510 processing condition setting field, 511 scan interval setting field,
512 Beam stay time setting field, 513 Processing type setting field,
514 Mask mode setting field, 515 Scan mode setting field,
600 image monitor window,

Claims (7)

A method for processing a fine sample by irradiating a sample with a focused ion beam,
Designation of an arbitrarily shaped processing area on the sample that is actually irradiated with the focused ion beam, designation of a non-processed area that is not processed by the focused ion beam, and processing by the focused ion beam on the microscope image acquired for the sample Specify the machining area and
Processing data of an arbitrary shape processing region is created by converting coordinates on a microscopic image corresponding to a region portion that does not overlap with the non-processing region in the processing region into beam irradiation position coordinates on the sample. Processing method for fine samples. A method for processing a fine sample by irradiating a sample with a focused ion beam,
Designation of an arbitrarily shaped processing area on the sample that is actually irradiated with the focused ion beam, designation of a non-processed area that is not processed by the focused ion beam, and processing by the focused ion beam on the microscope image acquired for the sample Specify the machining area and
Furthermore, when specifying the processing region, set the scanning method of the focused ion beam in relation to the boundary of the region,
Based on the set focused ion beam scanning method, the coordinates on the microscopic image corresponding to the region of the processing region that does not overlap with the non-processing region are converted to the beam irradiation position coordinates on the sample. A processing method of a fine sample that creates processing data of an arbitrarily shaped processing region. The method of scanning a focused ion beam in relation to the boundary of the processing region includes a beam scanning movement from the processing region boundary to the inside of the region and a beam scanning from the inside of the processing region to the region boundary. 3. The method for processing a fine sample according to claim 2, further comprising movement. 2. The method for processing a fine sample according to claim 1, wherein an observation image obtained by observing the fine sample with a high acceleration electron beam is used in combination with the fine sample. A focused ion beam processing apparatus for processing a sample by irradiating the sample with a focused ion beam,
Designation of the arbitrarily shaped processing area on the specimen that is actually irradiated with the focused ion beam, on the scanning ion microscope image, the non-processed area that is not processed with the focused ion beam corresponding to the target region and the processing with the focused ion beam A designation means for superimposing a machining area to be performed ;
The non-processed area specified by the specifying means and the processed area are synthesized, and based on the synthesis result , the coordinates on the microscopic image corresponding to the area portion that does not overlap the non-processed area in the processed area are obtained. A focused ion beam processing apparatus comprising processing data generating means for generating processing data converted into beam irradiation position coordinates in an arbitrary shape processing region. 6. The focused ion beam processing apparatus according to claim 5, wherein the specifying means includes a scanning method specifying means for specifying a scanning method of the focused ion beam in the specified processing region. A focused ion beam processing apparatus for processing a sample by irradiating the sample with a focused ion beam,
Designation of the arbitrarily shaped processing area on the specimen that is actually irradiated with the focused ion beam, on the scanning ion microscope image, the non-processed area that is not processed with the focused ion beam corresponding to the target region and the processing with the focused ion beam A designation means for superimposing a machining area to be performed ;
The non-processed area specified by the specifying means and the processed area are synthesized, and based on the synthesis result , the coordinates on the microscopic image corresponding to the area portion that does not overlap the non-processed area in the processed area are obtained. Machining data creation means for creating machining data converted into beam irradiation position coordinates of an arbitrarily shaped machining area,
A focused ion beam processing apparatus characterized in that an electron beam column is provided in addition to a focused ion beam column in a sample chamber in which a processed sample is accommodated.

Images