JP2004276103A - Specimen machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an FIB (Focused Ion Beam) machining apparatus capable of optimizing the machining order of machining positions scattered on a specimen to be machined. <P>SOLUTION: The FIB machining needing a plurality of processes is performed by optimizing the machining order. Thus, the shortening of a stage moving distance, the reduction of the number of times of stage rotation and the reduction of the number of times of a mechanical change for selecting kinds of machining are realized to shorten the total machining time and improve the machining precision. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a processing method and a processing apparatus using a focused ion beam (FIB).
[0002]
[Prior art]
2. Description of the Related Art An FIB apparatus is used for processing a cross section of a fine device or a new functional material, manufacturing a sample for a transmission electron microscope, or micromachining a fine mechanical part (see, for example, Patent Document 1). For example, FIB processing for cutting a sample from a sample involves moving the stage to process different locations on the sample, rotating the stage to process from different directions, changing the beam current and beam diameter, and changing from sputtering to deposition. A plurality of steps including the steps are required. As a method for sampling processing, a simple processing method of individually processing a desired shape at a desired position on a sample under desired conditions, and a process of cutting out one sample by combining a plurality of individual processings are continuously executed. There is a sampling processing method or an automatic processing method in which a plurality of sampling processings are prepared and executed collectively.
[0003]
[Patent Document 1]
Japanese Patent Publication No. 7-71755
[0004]
[Problems to be solved by the invention]
In any of the simple processing method, the sampling processing method, and the automatic processing method, processing is performed according to the processing procedure set by the operator. Therefore, useless movement may be forced in view of the mechanism and performance of the apparatus, and this has resulted in waste of total processing time and instability of processing accuracy.
An object of the present invention is to provide an FIB processing method which optimizes the processing order of processing locations scattered on a sample to be processed in view of the problems of the related art.
[0005]
[Means for Solving the Problems]
The present invention reduces the stage moving distance, reduces the number of stage rotations, and selects the type of processing by performing the processing in a proper order in FIB processing that requires a plurality of steps. Reduces the number of mechanism switching times, shortens total machining time and improves machining accuracy.
[0006]
That is, the sample processing method according to the present invention is a sample processing method in which a focused ion beam is irradiated from a diagonal direction on a sample held on a translationally and rotatable stage. Dividing the stage into a set of minimum processing units that can be processed without changing the stage, changing the beam type, and changing the processing type, and selecting the current stage and beam from a plurality of unprocessed minimum processing units. The method includes a step of searching for a minimum processing unit to be processed next based on a relationship between the type and the state of the processing type, and a step of processing the searched minimum processing unit.
[0007]
Next, it is also possible to sequentially search for the minimum processing unit to be processed, determine only the processing order first, and then continuously process the sample according to the determined order.
[0008]
The stage movement includes translation and rotation of the stage, and the beam type includes a rough processing beam having a large beam diameter and beam current, a medium processing beam, and a finishing beam having a small beam diameter and a small current. . The processing types include sputtering and deposition.
[0009]
The search for the minimum processing unit to be processed next is performed in consideration of the processing efficiency. Specifically, it is preferable to search for the minimum processing unit that can start processing in the shortest time from the current state as the minimum processing unit to be processed next. Further, the search for the minimum processing unit to be processed next needs to be performed in consideration of the precondition for starting processing of each minimum processing unit.
[0010]
The sample processing method according to the present invention is also directed to a sample processing method in which a focused ion beam is irradiated from a diagonal direction on a sample held on a translationally and rotatable stage. Step of dividing the stage into a set of minimum processing units that can be processed without changing the stage, changing the beam type, and changing the processing type based on, information on the processing location, information on the direction of beam irradiation for each minimum processing unit, Steps for creating a processing information table that describes information including beam type information and processing type information, and setting penalties for stage translation, stage rotation, beam type change, and process type change Step, the current stage, beam type and processing type status are compared with the processing information table, A small minimum feature units of penalty upon transition from state, characterized in that it comprises the steps of selecting as the next processing. Usually, the smallest processing unit having the smallest penalty is selected as the next processing.
Preferably, the processing information includes a flag indicating whether or not processing has been performed, and information on preconditions for starting processing.
[0011]
A sample processing method according to the present invention is directed to a sample processing method for irradiating a focused ion beam from a diagonal direction to a sample held on a translationally and rotatable stage and processing the sample under the same preconditions. Dividing into a set of minimum processing units that can be processed without changing the stage, changing the beam type, and changing the processing type; information on the processing location, information on the direction of beam irradiation, and beam type for each minimum processing unit And a step of creating a processing information table describing information including information on the processing type, based on coefficients given for stage movement, stage rotation, beam type change, and processing type change, respectively. The current stage, beam type and processing type status are compared with the processing information table, and the minimum processing is performed based on the current state. Characterized in that it comprises calculating a total cost of transition to position, and selecting a smaller minimum processing unit of the total cost as the next processing. Usually, the minimum processing unit having the smallest total cost is selected as the next processing.
[0012]
It is preferable that the processing information table includes information on preconditions for starting processing of each minimum processing unit, and that the total cost is calculated for the minimum processing unit satisfying the precondition.
[0013]
The coefficient may be derived based on the data of the time required for the movement of the stage, the rotation of the stage, the change of the beam type, and the change of the processing type, which are stored in advance. Alternatively, a preset value based on the specifications of the device may be used.
[0014]
According to the present invention, it is possible to perform processing on a more efficient path by matching the mechanism switching time of the FIB device with the stage positioning time. Further, by measuring the time for the mechanism switching and the stage positioning, and storing and reusing the time, the effectiveness of the path selection can be enhanced. Since the number of switching mechanisms is reduced, machining accuracy is improved. Also, even if the stage is temporarily moved during the processing to adjust the beam and the beam is moved to a location different from the processing location, the most efficient processing location is viewed from the current location different from the processing location by the processing restart instruction. It is possible to restart machining from.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Data relating to the processing procedure and conditions for the sample to be processed is called a recipe, and an operator creates a new recipe or reuses an already created recipe to give a processing instruction to the apparatus. When the FIB apparatus executes a recipe according to an instruction from an operator, the FIB apparatus first interprets the contents of the recipe. At this time, the minimum processing executed by continuously deflecting and irradiating the focused ion beam to a desired range is regarded as one processing location (minimum processing unit), and the recipe is subdivided into a set of processing locations. And a processing information table is created for each processing location. The processing information table includes the processed flag, processing preconditions, processing location (coordinates on the sample), processing direction, type of focused ion beam (rough processing, medium processing, finishing processing), and processing type (sputtering or Position) information. In the recipe interpretation, the current apparatus state is obtained, collated with each processing information table, and the most efficient processing part is determined from the current apparatus state. However, since individual processing may have a context with other processing, if it does not meet the preconditions, it is excluded from the selection candidates. When the processing of the highest-priority processing portion at that time thus determined is completed, the processed flag in the processing information table for that portion is turned on. In this way, processing is performed on all processing points while deriving an appropriate processing point each time from the current state of the processing point and the contents of the processing information table.
[0016]
By assigning comparison priorities to the processing information items themselves, it is also possible to preferentially select the processing in which the prioritized item has the same condition as the current one. In addition, a coefficient that represents the complexity of moving to processing for each item is prepared, and the degree of departure from the current state is expressed using this coefficient, and the processing part with the smallest sum may be used as the next candidate. it can. For the coefficients at this time, there are prepared a method of storing the coefficients in the processing information table and a method of externally referencing the items using the items as keys.
[0017]
As for the timing for determining the processing order, a batch method for determining the processing schedule at once at the start of the recipe and a sequential method for determining the next processing candidate while processing are prepared. The former has the advantage that the operator can be notified of the schedule in advance before processing, while the latter has the flexibility to handle exceptional processing during processing, such as when the operator needs to move the stage or adjust the beam. There are advantages that can be done. The function of dynamically deriving the next machining point suitable for the current state is implemented as software executed by a computer.
[0018]
FIG. 1 is a schematic diagram showing a configuration example of a FIB processing apparatus according to the present invention. A focused ion beam (FIB) 2 inclined 45 ° from a direction perpendicular to the surface of the sample to be processed passes through an aperture 5, is focused by a focused ion beam optical system 6, and is irradiated on the sample 1. The sample stage on which the sample 1 is mounted is composed of an XYZ stage 3 that can move in three axes of X, Y, and Z, and an R stage 4 that can rotate the sample in the horizontal direction. It is possible to observe the sample from an angle of elevation of 45 degrees and to process with a focused ion beam.
[0019]
The observation of the sample is performed by detecting secondary charged particles generated from the sample with the detector 8 and displaying the sample image on the display device 13 via the computer 10. While observing the sample image displayed on the display device 13, the observation region and the processing region of the sample are determined, and the control of the focused ion beam optical system 6 and the aperture 5 is performed via the linked beam deflection control device 14. Do. Above the XYZ stage 3, a Z sensor 16 for detecting the height of the sample on the stage is provided. The computer 10 includes an apparatus control program for controlling the entire apparatus, a state monitoring program for recognizing the current apparatus state, and a recipe execution program for performing processing and control relating to recipes.
[0020]
In the processing, the ion beam 2 focused from the focused ion beam optical system 6 is irradiated to an arbitrary position on the sample 1 to cut the sample 1, and a tungsten compound gas or a carbon compound gas is used as a gas source, and There is a deposition in which a gas is released near the sample by the position gun 7 and a film is formed on the sample 1. The setting of processing is performed by inputting processing setting information from the information input device 11 while viewing the sample image displayed on the display device 13. That is, while viewing the imaged secondary electron image of the sample, the sample stages 3 and 4 are moved, the deflection area of the beam 2 is designated, and a figure superimposed on the sample image of the display device 13 is used. To determine the position to hit the beam. After the processing region is determined, the beam, diameter, time, sputtering / deposition, and other conditions used for processing are designated, and processing is performed.
[0021]
As a feature of this FIB processing apparatus, there is a function of cutting out small pieces from a sample using processing by a focused ion beam called microsampling. This microsampling is a function of cutting the periphery of a sample to be taken out by sputtering, bonding the probe 9 to the sample by deposition, and transferring the probe 9 to a dedicated table called a cartridge 15.
[0022]
In this apparatus, a processing procedure called a recipe is created by using the display device 13 and the information input device 11 to create a processing procedure called a recipe, and stored in the storage device 12. can do.
[0023]
FIG. 2 is a diagram showing an example of the recipe execution operation screen 20 displayed on the screen display device 13 when executing a recipe. The processing method includes “One by One”, which advances the processing while sequentially deriving an appropriate processing portion, or “Batch”, which derives all the processing paths at the time of the processing start instruction. The operator selects a processing method using the menu button 21 of the recipe execution operation screen 20. When the menu button 22 for selecting the mechanism operation database is used, “Default” using a mechanism operation database defined in advance in the device and “Flexible” using a mechanism operation database reflecting a result of operating the device are used. Either can be selected. The “Top Start” button 23 is an instruction button for instructing execution from the beginning of the recipe, and the “Continue” button 24 is a button for instructing restart of the recipe when it is stopped halfway. The “Pause” button 25 is a button for interrupting the recipe halfway, and can be restarted by the “Continue” button 24. The “Stop” button 26 is a button for completely stopping the recipe, and after pressing this button to stop the recipe, the recipe processing cannot be continued by the “Continue” button 24.
[0024]
First, the processing for cutting out one sample from a sample using the micro-sampling function of the FIB processing apparatus shown in FIG. 1 will be described with reference to FIGS. 3A and 3B are views showing a typical processing portion for cutting out a sample from a sample, FIG. 3A is a schematic plan view of a sample processing region of the sample, and FIG. FIG. 3C is a BB cross-sectional view. FIG. 4 is a diagram three-dimensionally showing a sample cut out from the sample. FIG. 5 is a flowchart showing a processing procedure for sampling.
[0025]
In FIG. 3, reference numeral 31 denotes a marker which serves as a guide when the sample 39 is processed into a thin film. The marker 31 is marked using a sputtering phenomenon caused by irradiation of the focused ion beam 2 on the sample surface. Reference numeral 36 denotes a metal deposition film for detecting electrical conduction when the probe is bonded. The fact that the sample connected to the probe is separated from the sample and loses electrical continuity between the sample and the sample body is used to detect that the sample has been removed from the sample. Reference numeral 32 denotes a deposition film for protecting the sample surface. This film has a role of preventing the shavings of the sample from depositing on the sample surface due to the peripheral processing of the sample and preventing the sample surface from being scraped off by the nearby processing when the sample is cut. The large lateral groove 33, the small lateral groove 34, and the vertical groove 35, which are the three peripheral sides, are processed by using the vertical irradiation angle of the focused ion beam. The oblique groove 37 is cut by utilizing the fact that the focused ion beam is inclined by 45 °. Since the beam irradiation direction is fixed, the irradiation direction is changed by rotating the stage when cutting out one sample. In order to perform one sampling in this way, it is necessary to consider processing around the sample, deposition, movement and rotation of the stage, change of the beam used, and the like. In some cases, steps such as beam adjustment and processing position correction may be inserted during the processing.
FIG. 4 schematically shows the surrounding cutting and the adhesion state of the deposition film when the sample is cut out from the sample as described in FIG.
[0026]
Next, a procedure for cutting out one sample 39 from a sample will be described with reference to the flowchart of FIG. First, the orientation of the observation surface of the sample 1 is determined (S11) so that the observation surface is parallel to the vertical plane including the focused ion beam 2. When the directions are orthogonal to each other, the stage 4 is rotated right by 90 ° (S12). After rotating 90 °, the XYZ stage 3 is moved so that the sample enters the deflection region of the focused ion beam. When the rotation of the R stage is performed, processing position alignment (alignment) is required to determine an accurate processing position. Alignment occurs after the rotation of the R stage. This alignment process may take several minutes. Further, the shake in the Z direction caused by the XY movement of the stage 3 is corrected. Blurring in the Z direction is detected by a Z sensor 16 that detects a Z position by irradiating a laser beam onto a sample and receiving reflected light thereof. The Z correction is required every time the XYZ stage 3 or the R stage 4 moves.
[0027]
Next, two markers 31 are drawn as marks on the observation surface (S13). Since these two markers fall within the deflection area of the focused ion beam 2, no stage movement occurs at this time. At the same location, a protective film is created to prevent the sample surface from being eroded by the beam. The deposition function is used for attaching this film. The deposition gun 7 is usually at the retracted position so that the nozzle does not interfere with the sample, and when the deposition function is required, the tip of the nozzle is brought near the beam (S14). A protective film is formed by irradiating a focused ion beam while ejecting gas from the deposition gun 7 (S15). After the film is formed by the deposition, the nozzle is returned to the retracted position (S16). The insertion and removal of the deposition gun 7 is a process included in the deposition function, and controls up to and out of the nozzle according to a deposition processing execution instruction. In individual processing such as drawing of a marker and formation of a protective film, a beam used for the processing is often used properly, and switching of the beam involves switching of a mechanism such as the aperture 5.
[0028]
Next, the R stage 4 is rotated to the left by 90 ° to cut the lateral groove (S17). This is for making the lateral groove surface of the sample vertical. Subsequently, the large lateral groove and the small lateral groove are cut (S18, S19). Thereafter, the R stage 4 is rotated 90 degrees to the right (S20), and the vertical groove is cut (S21). Here, it is determined whether the sample surface is an insulator or a conductor (S22). In the case of an insulator, a contact pad which is a metal deposition film for detecting that the sample has separated from the sample is formed (S23, S24, S25). The deposition film is offset so as to be formed also on the sample wall surface.
[0029]
Thereafter, the R stage 4 is rotated again by 90 ° (S26). The tip of the probe 9 is grounded to the contact pad surface (S27), and the probe 9 and the sample are adhered by being deposited near the grounded portion (S28, S29, S30). After bonding, the oblique groove is cut (S31). Thus, the sample is separated from the sample, and the sample is pulled up to the retreat position together with the probe 9 (S32).
[0030]
In this state, the XYZ stage 3 is moved XY so that the cartridge 15 which is the sample transfer position is located below the probe 9 (S33). The probe 9 with the sample is lowered to a predetermined position of the cartridge 15 (S34), and the sample is adhered by deposition (S35, S36, S37). After bonding, the tip of the probe 9 is irradiated with a beam and cut (S38). Since the tip of the probe becomes thicker each time it is cut, the tip of the probe is polished by irradiating a beam (S39). Thereafter, the probe is retracted (S40).
[0031]
The above is one cycle when one sample is taken out of the sample. In the conventional method, when a plurality of samples exist on one sample, this is repeated. One cycle requires at least three R-stage rotations and alignments. Since the stage rotation process involves not only rotation but also processes such as XY movement, alignment, and Z correction, it greatly affects the total processing time and accuracy. Therefore, it is desirable to reduce the number of processes as much as possible.
[0032]
When cutting out two or more samples from the sample, if processing can be performed in the same direction, it is more efficient to continue processing even if the XY stage is moved, rather than performing processing around one sample sequentially. Is good. The method of processing the same direction continuously increases the amount of movement of the XY stage, but the method of processing the periphery of the sample sequentially generates three rotations of the R stage for each sample. If the sample moves away from the center of the R stage due to the rotation, the sample position deviates from the original position. Therefore, the XY stage must be moved to the original position. In consideration of the alignment, the Z correction, and the return of the XY stage, it is effective to use a method in which portions that can be processed in the same direction are continuously processed. Further, there are cases where processing conditions are different even in the same direction of processing. For example, the type of beam and the processing method are different between the deposition processing of the protective film and the processing of the marker. Since the difference between these conditions is related to the switching of the mechanism, it is desirable to adopt a method in which machining under the same conditions is continuously performed so as to minimize the switching of the mechanism.
Next, an algorithm of the present invention for determining the processing order will be described. The algorithm of the present invention for determining the processing order is dynamic.
[0033]
FIG. 6 is a diagram illustrating an example of a processing information table used when determining a processing order. The processing information table is a set of individual elements E1 to E9 held for each processing location. The data constituting the processing information table consists of the processing name such as processing name, processing completed flag, precondition, stage direction when processing, stage position, beam type, sputtering and deposition, etc. It is held for each machining point. This table is used to proceed with the processing from the processing location having the condition most suitable for the current apparatus state. The “direction” described in the individual elements E1 to E9 shown in the drawing expresses from which direction in the drawing the processing should be performed in the state shown. For example, a portion to be processed by applying a beam from the lower side of the figure in the illustrated state is described as “from the bottom”, and a portion to be processed by applying the beam from the left side of the figure is described as “from the left”. I have.
[0034]
As an example, the priority of the processing is, as viewed from the final processing state, which can also be referred to as the current apparatus state, (1) indicates that the processing performed flag is not performed, and indicates that the processing is possible, that is, the precondition is Satisfaction has the highest priority, and then (2) the stage orientation is the same direction (does not cause stage rotation), (3) does not cause stage movement, and (4) control the deposition gun. No, (5) without beam control. The processing that matches this condition as much as possible is determined as the processing part to be processed next.
[0035]
A mechanism for dynamically changing the priority itself is provided. This is a method in which the priorities of the respective processes are described in advance in the definition table, and the processes are executed from the processes according to the description. For example, since the beam switching process is usually lighter in control of the mechanism than the stage rotation process, reducing the beam switching process is not regarded as important, that is, the priority is set lower than the stage rotation process. . Therefore, as shown in FIG. 7A, the upper order record of the priority order definition table is described in the order of the stage rotation process (without accompanying) and the lower order of the beam switching process (without accompanying). In this priority order definition table, for example, as shown in FIG. 7B, when the description order of the stage rotation processing and the beam switching processing is exchanged, the processing priority is changed and the number of times of beam switching is reduced as much as possible. The processing order is set. By making the processing procedure dynamic in this way, even when the number of samples obtained increases, the processing can proceed autonomously without describing a complicated processing procedure.
[0036]
Next, an example of processing when two samples are taken out of a sample according to the algorithm will be described. FIG. 8 is a schematic diagram showing a positional relationship between two samples on the sample 1. C1 is a vertical sample whose observation surface is parallel to the focused ion beam, and C2 is a horizontal sample whose observation surface is perpendicular to the focused ion beam. Using this example, FIG. 9 shows a procedure of processing for reducing the number of rotations of the R stage in accordance with the priority order table shown in FIG.
[0037]
First, the large lateral groove of C2 is subjected to sputtering (S41). The small horizontal groove of C2 is machined in the same deflection area of the focused ion beam without moving the stage (S42). The portion that can be processed at the current stage position is diagonal groove processing. However, since this processing is processing for separating the probe after bonding, processing cannot be performed at the current timing. Since the direction of the focused ion beam is different from the original processing direction in the remaining part, it is determined that there is no part that can be currently processed with this sample. Therefore, the XY stage 3 is moved XY to the C1 sample position (S43). In the C1 processing part, the part that can be processed in this state is two markers (S44). Since the protective film can be deposited, the process is performed here (S45). Thereafter, since there is no place that can be processed in this direction, the R stage 4 is rotated 90 ° to the left (S46).
[0038]
As a result of the rotation, the stage is moved XY to a sample position that is close when viewed from immediately below the current beam. In this case, since C1 is closer to C2, the process of forming a large lateral groove of C1 is started (S47). Thereafter, the small lateral groove of C1 is processed (S48). Since there is no processing location at C1 in the current direction, the XY stage 3 is moved to C2 (S49). In C2, two markers are drawn (S50), and the protection film is deposited (S51). Since the horizontal groove of C2 has already been processed, the vertical groove is processed (S52). Machining the vertical groove before the protective deposition of C2 is more efficient because it does not involve the insertion and removal of the deposition gun. Positions are implemented first.
[0039]
Next, the contact pad of C2 is deposited, but at a position relatively opposite to the position of the contact pad of C1 (S53). This takes into account the fact that the focused ion beam is irradiated in the current direction, that is, in the sample direction when viewed from the lateral groove size, and the deposition film is efficiently formed on the sample lateral wall surface. Thereafter, there is a diagonal groove of C1 as a portion that can be processed in this state, but since the vertical groove of C1 is not processed, it is postponed. Therefore, there is no place that can be machined in this state, and the R stage 4 is rotated right by 90 ° (S54).
[0040]
Since the closest workable portion as viewed from immediately below the current beam is the vertical groove of C1, the XY stage 3 moves the XY motion (S55), and processes it (S56). Next, a contact pad of C1 is formed (S57). Since there is no part that can be processed without rotating the stage in C1, the stage is moved to the vicinity of C2 (S58), and the probe 9 is deposited and adhered to the contact pad (S59). After the bonding, the sample is separated from the sample 1 by processing the diagonal groove of C2. Thereafter, the probe 9 is pulled up, and the XY stage 3 is moved to the cartridge 15. The probe 9 is lowered to the position where the cartridge is bonded, and when the sample comes into contact with the cartridge, it is bonded by deposition. After the completion of the deposition, the probe 9 is cut by the focused ion beam (S60).
[0041]
After raising the probe 9 to the retracted position, the R stage 4 is rotated counterclockwise by 90 ° to take out the C1 sample (S61), and the XY stage 3 is moved to the vicinity of C1 (S62). The probe 9 is lowered to the contact pad position of C1, and the sample is adhered by deposition (S63). After bonding, the diagonal groove of C1 is cut, and the sample is cut off from the sample. Thereafter, stage movement, probe operation, and deposition control are performed in the same manner as in the method in which the C2 sample is attached to the cartridge (S64).
[0042]
The feature of this processing is that the current stage position and orientation and the sampling process are taken into account, and two samples can be obtained by three stage rotations. This method can also be applied when the number of samples taken from one sample is three or more.
[0043]
Conventionally, when there are a plurality of locations on a single sample to be processed by the FIB processing apparatus, the processing is performed in the order described in the recipe created by the operator, so that there is a useless movement in the apparatus control and the processing is performed. It takes a long time, and the switching of the hardware mechanism frequently occurs, and the machining accuracy is reduced. According to the method of the present invention, useless movements of these devices and the number of switching mechanisms can be reduced, so that the total processing time can be reduced and the processing accuracy can be improved. For example, looking at the number of R-stage rotations, three times are required to obtain one sample from a sample. In the conventional method, taking out n samples requires 3n R-stage rotations. On the other hand, in this method, even if the number n of samples increases, the number of rotations of the R stage is only three. The alignment process associated with the rotation may take several minutes, and therefore, when acquiring a plurality of samples, the total processing time is significantly reduced according to the method of the present invention.
[0044]
Next, another example of the algorithm for determining the processing order will be described. The example described here is a method in which a time element is considered in weighting. According to this method, priority is given to beam switching when the stage movement distance is large, and priority is given to stage movement when the aperture switching distance is long. It is possible to do.
[0045]
FIG. 10 is an explanatory diagram showing a method of assigning coefficients to elements related to mechanism control among the elements described in the processing information table, and comparing the total costs thereof to determine the next processing. In the example shown, as shown in the conversion coefficient table F2, 50 points for stage rotation per unit (90 °), 1 point for stage movement per unit distance, 6 points for beam switching to an adjacent aperture, and processing position. 18 points are assigned to the movement of the deposition gun to the position or the evacuation of the deposition gun from the processing position, and the total points of the mechanism control required to shift from the current state F1 to each processing position are calculated as a total cost, Compare. In the example shown in the figure, the difference between the current state F1 and the candidate groups F3, F4, and F5 is quantified. As a result, the processing name “1 protection deposition” (F3) has the lowest total cost “54”. This is the next processing.
[0046]
The conversion coefficient table F2 shown in FIG. 10 is calculated based on the time when the device mechanism actually works. Specifically, a command acting on the device is input from the information input device 11, and the time until the device returns a response indicating completion is measured. This time is converted into the unit of each control mechanism. For example, the stage is stored in the storage device 12 as a movement amount (speed) per unit time. In this method, the latest data can be used for deriving the next route every time the device operates. Separately, the device specification data before the execution of the recipe is provided, and a mechanism for switching and using the two is prepared. The required time for stage movement and beam switching depends on the amount of movement. On the other hand, the direction change and the insertion / removal of the deposition gun do not take a linear value, so that the total time is maintained.
[0047]
With respect to systems that can be controlled at the same time due to the mechanism of the apparatus, one of them may be effectively hidden by the control time of the other due to the combination. In a system capable of parallel processing, the combination is tabulated, and the control time of the system that is actually hidden is treated as 0, so that the total cost can be reduced and the priority can be increased.
[0048]
FIG. 11 is a diagram for explaining a processing example of the state monitoring program mounted on the computer 10. The status monitoring program includes a process 41 for acquiring the current status of the device and a process 42 for collecting the distance and time when a mechanism such as a stage and an aperture of the device is operated and updating the mechanism operation database 43. The former acquires the direction of the stage, the position of the stage, the type of beam, and the type of processing such as sputtering or deposition. This acquired data is used by the recipe execution program to derive an appropriate processing location to be processed next. In the latter, the stage movement speed, aperture switching speed, deposition gun insertion / removal speed, alignment required time, Z correction time, and the like are acquired from the apparatus. These pieces of information are overwritten as the latest data in the mechanism operation database 43 at the acquired timing. As the mechanism operation database, a default mechanism operation database holding a preset default value is prepared separately from this, and it is possible to select which method is used to execute the recipe according to the instruction of the operator.
[0049]
FIG. 12 is a flowchart illustrating a processing example of the recipe execution program. When executing a recipe, the operator selects an execution method on the recipe execution operation screen 20 shown in FIG. 2 (S71). The batch method is a method in which a sequence of all the processing is assembled in advance before executing the recipe, and the sequential method is a method in which the next processing part is determined when one processing is completed. After determining the execution method, the specified recipe is divided into minimum processing units (S72). Next, a processing information table is created in the divided minimum processing unit (S73). Next, the process proceeds to an optimal candidate selection process (S74). The optimal candidate selection process (S74) is a process for finding an appropriate processing location. The processing section finds the most suitable processing location from the processing information table based on the current apparatus state 90 and the information of the mechanism operation database 91 previously specified from the recipe execution operation screen. Is derived. The execution method is determined (S75), and when the specified execution method is the sequential method, the processing of the derived appropriate processing part is executed (S76). On the other hand, in the case of the batch method, the processing information of the derived optimum processing location is sequentially stored in the processing order table (S77).
[0050]
When the process goes through step 76, the current processing information table content becomes the current device state. If the processing goes through step 77, it is assumed that the processing location has been processed, and the contents of the processing information table are set to the current apparatus state (S78). In either method, the current processing location is determined to have been processed, and the completed flag is set to ON to prevent it from being the next processing candidate (S79), and the next appropriate candidate is selected (S74). Thus, the processing from step 74 to step 80 is repeated until there are no more processing candidates.
[0051]
Next, the execution mode is determined (S81). If the execution mode is the sequential method, the process ends when there are no more processing candidates. If the execution mode is the batch mode, the processing is executed continuously according to the order held in the processing order table (S82). When it is necessary to perform an exceptional process such as adjustment of the focused ion beam during the sequential processing, the operator presses the “Pause” button on the recipe execution operation screen 20 of FIG. Then, after the execution of the single processing in step 76, the processing according to the recipe is temporarily interrupted. For example, the operator moves the stage by manual operation to bring the beam away from the sample, and adjusts the beam there. Thereafter, when the "Continue" button is pressed, in the process of step 78, the current device state is fetched instead of the content of the processing information table of the immediately preceding processed portion, and the process returns to the processing according to the recipe. Therefore, in the selection of the optimum candidate immediately after the interruption of the recipe (S74), the optimum processing candidate is selected by searching from the apparatus state after the exception processing.
[0052]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, useless movement of a FIB processing apparatus and the frequency | count of switching of a mechanism can be reduced, and the total processing time can be shortened and the processing accuracy can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration example of a FIB processing apparatus according to the present invention.
FIG. 2 is a diagram showing an example of a recipe execution operation screen.
FIG. 3 is a view showing a typical processing site for cutting out a sample from a sample.
FIG. 4 is a diagram showing a sample cut out from the sample in a three-dimensional manner.
FIG. 5 is a flowchart showing a processing procedure for sampling.
FIG. 6 is a view for explaining an example of a processing information table.
FIG. 7 is a diagram showing an example of a priority order definition table.
FIG. 8 is a schematic diagram showing a positional relationship between two samples on a sample.
FIG. 9 is a flowchart for processing a plurality of samplings in an appropriate processing order.
FIG. 10 is an explanatory diagram of a method of holding a mechanism switching time in a database and parameterizing the mechanism in order to derive an appropriate processing order at the next processing.
FIG. 11 illustrates a processing example of a state monitoring program.
FIG. 12 is a flowchart illustrating a processing example of a recipe execution program.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Processing object sample, 2 ... Focused ion beam, 3 ... XYZ triaxial stage, 4 ... R stage, 5 ... Aperture, 6 ... Focused ion beam optical system, 7 ... Gas ejection nozzle, 8 ... Detector, 9 ... Sampling Probe 10 Computer 11 Information input device 12 Storage device 13 Display device 14 Beam deflection control device 15 Cartridge 16 Z sensor 20 Recipe execution operation screen 31 Marker 32 ... Protective film, 33 ... Large lateral groove, 34 ... Small lateral groove, 35 ... Vertical groove, 36 ... Contact pad, 37 ... Diagonal groove, 38 ... Observation surface position, 39 ... Sample, C1 ... Vertical sample, C2 ... Horizontal sample

Claims (8)

In a sample processing method of processing by irradiating a focused ion beam from a diagonal direction to a sample held on a translational and rotatable stage,
Dividing the processing of the sample into a set of minimum processing units that can be processed without performing stage movement, changing the beam type and changing the processing type under the same preconditions,
A step of searching for a minimum processing unit to be processed next based on the relationship between the current stage, the beam type, and the state of the processing type from among the plurality of unprocessed minimum processing units;
Performing the processing of the searched minimum processing unit. In a sample processing method of processing by irradiating a focused ion beam from a diagonal direction to a sample held on a translational and rotatable stage,
Dividing the processing of the sample into a set of minimum processing units that can be processed without performing stage movement, changing the beam type and changing the processing type under the same preconditions,
For the set of minimum processing units, sequentially searching for the minimum processing unit to be processed next based on the current stage, the relationship between the beam type and the state of the processing type, and determining the order of processing,
Processing the sample in accordance with the determined order. 3. The sample processing method according to claim 1, wherein a minimum processing unit which can start processing in a shortest time from a current state is searched as a minimum processing unit to be processed next. 4. The sample processing method according to claim 1, wherein the search for the minimum processing unit to be processed next is performed in consideration of a precondition for starting processing of each minimum processing unit. . In a sample processing method of processing by irradiating a focused ion beam from a diagonal direction to a sample held on a translational and rotatable stage,
Dividing the processing of the sample into a set of minimum processing units that can be processed without performing stage movement, changing the beam type and changing the processing type under the same preconditions,
For each of the minimum processing units, a step of creating a processing information table describing information including processing information, information on a beam irradiation direction, information on a beam type, and information including information on a processing type,
Setting a penalty for translation of the stage, rotation of the stage, change of beam type and change of processing type,
Comparing the current stage, the state of the beam type and the processing type with the processing information table, and selecting the minimum processing unit having the smaller penalty as the next processing when shifting from the current state. Sample processing method. In a sample processing method of processing by irradiating a focused ion beam from a diagonal direction to a sample held on a translational and rotatable stage,
Dividing the processing of the sample into a set of minimum processing units that can be processed without performing stage movement, changing the beam type and changing the processing type under the same preconditions,
For each of the minimum processing units, creating a processing information table describing information including processing location, information on the direction of beam irradiation, information on the beam type, information including information on the processing type,
Based on the coefficients given for the movement of the stage, the rotation of the stage, the change in the beam type and the change in the processing type, the current stage, the state of the beam type and the processing type are compared with the processing information table, Calculating the total cost of transition from the current state to each minimum processing unit;
Selecting the minimum processing unit having a small total cost as the next processing. 7. The sample processing method according to claim 6, wherein the processing information table includes information on a precondition for starting processing of each minimum processing unit, and the calculation of the total cost is performed on the minimum processing unit satisfying the precondition. A sample processing method characterized by performing. 7. The sample processing method according to claim 6, wherein when the stage is moved, the stage is rotated, the beam type is changed, and the processing type is changed, data of time required for the change is stored, and the coefficient is stored in the data. A method for processing a sample, wherein the method is derived based on the following.

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