JP4634288B2 - Focused ion beam processing method and charged particle beam apparatus - Google Patents

Description

  The present invention relates to a technique for producing a thin sample for a transmission electron microscope using a focused ion beam, and more particularly to a focused ion beam processing method and charged particles suitable for producing a thin sample containing a defect to be observed from a semiconductor wafer. The present invention relates to a beam device.

  A thin piece having a thickness of about 0.1 μm is used as a sample for a transmission electron microscope. In recent years, focused ion beams have been used to make such thin specimens. By using the focused ion beam, a thin sample including a desired observation position can be reliably produced in a short time. For example, when observing a cross section of a semiconductor device or the like, a thin sample including the cross section at the observation position may be prepared. Non-Patent Documents 1 and 2 report a method for preparing a sample using such a focused ion beam.

  Japanese Patent Application Publication No. 2002-503870 discloses an apparatus and a method for processing a focused ion beam using a column and stage rotating function inclined with respect to a wafer. Japanese Laid-Open Patent Publication No. 5-52721 describes a method of cutting out a thin film sample piece using a focused ion beam and a probe.

"After preparing a sample for TEM with a focused ion beam" Surface Science: Vol.16, No.12, pp755-760,1995 “Transmission Electron Microscope Sample Preparation Using a Focused Ion Beam”: J Electron Microscope 43, pp322-326,1994 Yamamura, Y., "Energy dependence of the yield of ion-induced sputtering of monatomic solid," At. Dat. & Nuc. Dat. Tab. 62 (1996) 149) Special Table 2002-503870 Japanese Patent Laid-Open No. 5-52721

  Conventionally, when a minute piece sample including a defect position is cut out from a wafer using a focused ion beam, a rectangular groove is formed around the defect position to form a protrusion. Next, a minute piece is generated by cutting the base of the protrusion along the inclined surface. However, the conventional method has a drawback that the processing amount is large and the processing time is long.

  Further, in the conventional method, since the relationship between the set value of the processing amount and the actual processing amount is unknown, inefficient processing is performed to obtain a desired processing amount.

  The objective of this invention is providing the apparatus and method which can cut out a micro piece sample from a sample in a short time.

  According to the present invention, the setting value of the V-groove depth and the setting value of the V-groove width are calculated from the desired depth of the V-groove using an empirical formula so that the machining time is minimized. V-groove processing is performed by the focused ion beam according to the set value thus obtained. A fine piece is cut out from the sample surface only from the V-groove processing. An ion beam tilted with respect to the sample surface is used.

  According to the present invention, a minute piece sample can be cut out from a sample in a short time.

  According to the present invention, a minute piece sample is cut out from the sample surface by processing a V groove on the sample surface. That is, a micro-piece sample is created only by V-groove processing using a focused ion beam. Therefore, first, processing conditions when performing V-groove processing with a focused ion beam will be described. As shown in FIG. 5A, when the ion beam 25 scans the surface of the flat sample 40, the ion beam irradiation point is scraped by sputtering in accordance with the irradiation amount, and there is a difference in level before and after the beam scanning. It is formed. At the turning point of the beam scanning, a step is deepened between the portion that has received the beam and the portion that has not received the beam, and a recess is formed. Accordingly, inclined surfaces 40a and 40b are formed on the sample surface before and after ion beam scanning.

  As shown in FIG. 5B, the inclination angle of the inclined surface 40a is assumed to be θ. An angle formed by the normal line n of the inclined surface 40a and the optical axis 25A of the ion beam 25 is defined as a beam incident angle. The beam incident angle is equal to the inclination angle θ of the inclined surface 40a. Therefore, when the tilt angle is 0 degree, the beam incident angle is 0 degree, and when the tilt angle is 90 degrees, the beam incident angle is 90 degrees.

  Even if the ion beam is irradiated perpendicularly to the sample surface, since the concave portion is formed, the ion beam irradiation surface is inclined and the incident angle of the ion beam does not become 0 degree.

  The sputtering yield with an ion beam is a function of the incident angle of the ion beam. In Non-Patent Document 3, Yamamura has proposed the following equation as a theoretical expression that agrees well with the experimental results.

  Here, t = 1 / cos θ, and f and s are parameters. The curve in FIG. 6 is a graph when the parameters are f = 1.8 and s = 0.3 in the equation (1). The horizontal axis represents the ion beam incident angle, and the vertical axis represents the sputtering yield. However, the sputtering yield Y (E, θ) / Y (0) on the vertical axis is normalized by the sputtering yield Y (0) when the ion beam incident angle θ is 0.

  As shown by the curve in FIG. 6, the sputtering yield depends on the beam incident angle. The sputtering yield increases with the beam incident angle θ when the beam incident angle θ is 0 to 80 degrees. In particular, when the beam incident angle θ exceeds 50 degrees, the sputtering yield increases rapidly, and when the beam incident angle θ is about 80 degrees, the sputtering yield becomes maximum. When the beam incident angle θ exceeds 80 degrees, the sputtering yield decreases rapidly. As the beam incident angle θ is further increased, the sputtering yield becomes smaller than 1. If the beam incident angle when the sputtering yield is 1 is θc, θc is about 87 degrees. When the beam incident angle exceeds θc, the sputtering yield becomes very small and it is almost impossible to process.

  A wedge-shaped V-groove can be formed on the surface of the sample by utilizing the dependency of the sputtering yield on the beam incident angle. A flat sample surface is irradiated with an ion beam and scanned. Initially, since the beam incident angle is small, a small recess is formed. However, once the concave portion is formed and an inclined surface is formed, the beam incident angle increases and the amount of processing increases. When the amount of processing increases, the concave portion of the sample surface becomes deeper and the beam incident angle becomes larger. Thus, the processing amount increases as the beam incident angle increases. Accordingly, the inclined surface of the recess is rapidly scraped to form a wedge-shaped V-groove. When the inclination angle of the wedge-shaped V-groove reaches θc, the V-groove does not increase any more. Therefore, a V-groove having a cross section with a wedge-shaped apex angle approximately equal to 2θc is formed.

  Next, the relationship between the set value of the V groove and the depth of the actually processed V groove was examined. As shown in FIG. 7A, the V-groove was beam-processed with the groove width set value set to w (μm) and the depth set value set to H (μm). As shown in FIG. 7B, the depth d (μm) of the V groove actually formed by the beam processing was measured. The machining beam used was tilted by 45 ° with respect to the sample surface, but substantially the same result was obtained when it was incident perpendicular to the sample surface. From the experimental results, it was found that the following relational expression can be obtained.

  From this equation, the machining time t of the V groove having the groove width set value w, the length set value L, and the depth set value H is obtained by the following equation.

  t is the machining time (seconds), L is the groove length (μm), and Ib is the beam current (nA). Therefore, in order to obtain the condition w that minimizes the machining time t, the following condition may be calculated.

  When w satisfying Expression 4 is obtained, the following expression is obtained.

  If the depth d of the machining result is deleted from this equation, the following equation is obtained.

  However, H, w, and L are values when expressed in a rectangular coordinate system with the incident direction of the beam as the Z direction. When the sample and the beam are tilted, H and w are the beam direction and a component orthogonal to the beam direction, but L is the actual length to be processed with the angle between the line segment L and the beam as φ. Then, L ′ × sin φ = L may be set.

  Equation (6) represents the relationship between the depth setting value H and the groove width setting value w that minimize the processing time in ion beam processing. e is a natural logarithm and is constant. Accordingly, the ratio H / w of the depth setting value H to the groove width setting value w is approximately 7.4. When the ratio H / w is smaller than 7.4, that is, when the groove width setting value w is larger than the depth setting value H, the processing surface becomes flatter and the ion beam incident angle θ becomes smaller. The time will be longer. When the ratio H / w is larger than 7.4, that is, when the groove width setting value w is small with respect to the depth setting value H, the inclination of the machining surface is large, and the ion beam incident angle θ is large. Although the time is shortened, the depth set value H cannot be obtained.

  Next, the beam current Ib will be described. In order to shorten the processing time t from the equation (3), the beam current Ib may be increased. However, as the beam current increases, the beam opening angle increases. Thereby, the spherical aberration of the ion optical system is increased. Spherical aberration depends on the cube of the beam opening angle. As the spherical aberration increases, the spread of the base of the beam increases. When such a beam is used, the edge of the groove (processing edge) is broken, and the sampling surface is damaged. Therefore, there is a limit to the increase in beam current.

  Conversely, when the beam current is small, the processing time increases. For example, if the beam current is reduced from 20 nA to 10 nA, the processing time is doubled.

  FIG. 1 shows an example of a tilted column charged particle beam device according to the present invention. The tilted column charged particle beam apparatus of this example includes a sampling manipulator 10, a focused ion beam (FIB) column 20, a deposition gun 30, a wafer holder 41 for holding a sample wafer 40, X, Y, Z, R (rotation). ) Four-stage stage 42, vacuum evacuation device 43, and charged particle detector 45. On the stage 42, the x-axis and y-axis are taken on the horizontal plane, and the z-axis is taken vertically upward.

  The sampling manipulator 10 has a probe position control 11 and a sampling probe 12. The FIB column 20 includes an ion gun 21 made of a Ga liquid metal ion source, a beam limiting aperture 22 for limiting the ion beam 25, a lens system 23 for focusing the ion beam 25, and a deflector 24 for beam scanning on the wafer surface. Have The optical axis of the FIB column 20 is inclined by 45 ° with respect to the Z axis of the stage 42.

The deposition gun 30 includes a nozzle 31, a nozzle position and temperature control 32, and a deposition source reservoir 33. The deposition source reservoir 33 is filled with W (CO) ₆ .

  The tilted column charged particle beam apparatus of this example further includes a sampling manipulator control unit 51, a deposition gun control unit 52, an FIB control unit 53, a loader control unit 54, a stage control unit 55, an evacuation control unit 56, a display 57, A storage unit 58 and a CPU 59 are included.

  The sampling manipulator control unit 51 controls the sampling manipulator 10 to take out and change the minute piece sample separated from the wafer. The deposition gun control 52 controls the deposition gun 30 to control the temperature of the gas source and the nozzle position. The FIB control unit 53 controls the FIB column 20 to control ion beam acceleration, beam current, focus, and deflection. The loader control unit 54 controls the loading / unloading of the wafer holder 41.

  The stage control unit 55 performs drive / position control of the stage 42 based on position information measured by the laser length measurement system. The stage 42 is a four-axis stage that performs linear movement in the X, Y, and Z axis directions and rotation around the Z axis. In this example, since the position information is obtained by the laser length measurement system, it is possible to increase the sampling position accuracy. Therefore, it is possible to reliably sample the target location from the wafer.

  The vacuum exhaust control unit 56 controls the vacuum exhaust device 43. The display 57 displays an image obtained by a signal from the charged particle detector 45 synchronized with the scanning signal. The storage unit 58 stores an image. The CPU 59 centrally manages the entire tilted column charged particle beam apparatus.

  According to the charged particle beam apparatus of this example, when the user inputs a desired V groove depth d, the CPU 59 calculates the V groove depth setting value H and the width setting value w according to the equation (5). To do. The charged particle beam device forms a V-groove based on the depth setting value H and the width setting value w calculated by the CPU 59. Therefore, a V-groove having a desired depth d is formed in the shortest time.

  Next, a method of cutting out a minute piece including a defect without breaking the wafer using the inclined column charged particle beam apparatus of FIG. 1 will be described. According to the present invention, V-shaped groove processing is performed using the FIB column 20 having an optical axis inclined by 45 degrees with respect to the sample surface. The FIB column 20 is fixed, and a V-groove in an arbitrary direction can be formed only by moving and rotating the wafer. Small pieces are cut out only by V-groove processing.

  By obtaining the set value W of the width of the V groove and the set value H of the depth according to the equation (5) and using them as input values of the charged particle beam apparatus, the processing time is minimized.

  The case of forming a P-shaped V-groove will be described with reference to FIG. By forming the P-shaped V-shaped groove, a prismatic minute piece 105 having a right triangle cross section is obtained as shown in FIG.

  First, as shown in FIG. 2A, it is assumed that the optical axis 25A of the focused ion beam 25 is on the xz plane. Further, it is assumed that the optical axis 25A of the focused ion beam 25 is inclined 45 degrees with respect to the z-axis. By moving a wafer as a sample along the x-axis direction, V-grooves 101 and 102 in the x-axis direction are formed. The V grooves 101 and 102 are formed perpendicular to the surface of the wafer. FIG.2 (b) is sectional drawing seen along the arrow BB direction of Fig.2 (a). Both ends of the V-grooves 101 and 102 have inclined surfaces 101a and 101b corresponding to the inclination angle of the ion beam of 45 degrees. Next, the Y-axis direction V-groove 103 is formed by moving the wafer along the y-axis direction. FIG.2 (c) is sectional drawing seen along the arrow CC direction of Fig.2 (a). The cross section of the V groove 103 is inclined 45 degrees with respect to the surface of the wafer.

  Next, the sample wafer is rotated by -90 degrees around the z axis. Accordingly, as shown in FIG. 2D, the V-groove 103 is parallel to the x-axis, and the V-grooves 101 and 102 are parallel to the y-axis. By moving the wafer along the x-axis direction, the V-groove 104 in the x-axis direction is formed. FIG.2 (e) is sectional drawing seen along the arrow EE direction of FIG.2 (d). Both ends of the V-shaped groove 104 have inclined surfaces 104a and 104b corresponding to the inclination angle of the ion beam of 45 degrees.

  FIG. 2 (f) shows a state where the minute piece 105 is cut out by the four V grooves 101, 102, 103, 104. By forming the P-shaped V-shaped groove in this way, a prismatic minute piece 105 having a right triangle cross section is obtained.

  Next, the machining time is calculated. In this example, since the V-groove is processed using a beam inclined by 45 degrees with respect to the sample surface, for example, when forming a V-groove having a depth of 10 μm from the surface, the actual drilling depth, The processing depth is 10 × √2 μm = 14 μm. D in the formula 5 represents the machining depth. Therefore, the machining depth d is obtained from the shape of the V groove to be actually machined, and is substituted into the equation 5 to obtain the V groove width setting value W and the depth setting value H.

  As shown in FIG. 2F, here, the dimension of the minute piece 105 is 14 μm × 10 μm × 10 μm. However, the height is 10 μm. The depth from the surface of the V grooves 101 and 102 is equal to the height of the minute piece 105 and is 10 μm, but the actual processing depth is required to be at least 14 μm. Here, an extra 3 μm is excavated, and the processing depth is d = 17 μm.

  The width setting value w and the depth setting value H of the V-grooves 101 and 102 are w = 2 μm and H = 15 μm from the equation (5). Similarly, the processing depth of the V groove 103 is d = 17 μm. Similarly, the set value w of the width of the V-groove 103 and the set value H of the depth are w = 2 μm and H = 15 μm from the equation (5).

The processing length of the V grooves 101 and 102 is L = 10 μm, and the processing length of the V groove 103 is L = 16 μm. From Equation 3, the processing time for the V grooves 101 and 102 is 56 s, and the processing time for the V groove 103 is 89 s. However, the material of the wafer was silicon and the beam current was 20 nA. The sputtering yield was Y (0) = 0.27 (μm ³ / nC).

  The processing depth of the V groove 104 is d = 17 μm. The width setting value w and the depth setting value H of the V-groove 104 are w = 2 μm and H = 15 μm from the equation (5). The processing length of the V groove 104 is L = 20 μm. Accordingly, the processing time is 111 s from the equation of Equation 3. Therefore, the processing time required for sampling a small piece having a right triangle cross section is 56 s × 2 + 89 s + 111 s = 312 s. That is, about 5 minutes. Here, the case of processing with a beam current of 20 nA has been described. When the beam current is about 10 nA, the processing time is about twice as long as about 10 minutes.

  FIG. 3 shows a state in which the sampling probe 12 is adhered to the upper surface of the minute piece 105. The tip of the sampling probe 12 is adhered to the minute piece 105 before or after the minute piece 105 is completely separated by the four V grooves 101, 102, 103, 104. In this way, the minute piece 105 is completely separated while the minute piece 105 is held by the sampling probe 12.

  A case where a V-shaped V-shaped groove is formed will be described with reference to FIG. By forming a B-shaped V-shaped groove, a prismatic minute piece 205 having an isosceles triangular cross section is obtained as shown in FIG.

  First, as shown in FIG. 4A, it is assumed that the optical axis 25A of the focused ion beam 25 is on the xz plane. Further, it is assumed that the optical axis 25A of the focused ion beam 25 is inclined 45 degrees with respect to the z-axis. By moving a wafer as a sample along the x-axis direction, V grooves 201 and 202 in the x-axis direction are formed. The V grooves 201 and 202 are formed perpendicular to the wafer surface. FIG. 4B is a cross-sectional view taken along the direction of the arrow BB in FIG. Both ends of the V-grooves 201 and 202 have inclined surfaces 201a and 201b corresponding to the inclination angle of the ion beam of 45 degrees. Next, the V-groove 203 in the y-axis direction is formed by moving the wafer along the y-axis direction. FIG.4 (c) is sectional drawing seen along the arrow CC direction of Fig.4 (a). The cross section of the V groove 203 is inclined 45 degrees with respect to the wafer surface.

  Next, the sample wafer is rotated 180 degrees around the z-axis. Accordingly, as shown in FIG. 4D, the V-groove 203 is parallel to the y-axis, and the V-grooves 201 and 202 are parallel to the x-axis. By moving the wafer along the y-axis direction, the V-groove 204 in the y-axis direction is formed. FIG. 4E is a cross-sectional view taken along the direction of the arrow EE in FIG. The cross section of the V groove 204 is inclined 45 degrees with respect to the wafer surface.

  FIG. 4F shows a state in which the minute piece 205 is cut out by the four V grooves 201, 202, 203, 204.

  Actually, in order to cut out the minute piece 205, the sampling probe 12 is used as described with reference to FIG. Before the micro piece 205 is completely separated by the four V grooves 201, 202, 203, 204, the tip of the sampling probe 12 is adhered to the upper surface of the micro piece 205. In this way, the minute piece 205 is completely separated while the minute piece 205 is held by the sampling probe 12.

  By forming a square V-shaped groove in this manner, a prismatic minute piece 205 having an isosceles triangular cross section is obtained.

  Next, the machining time is calculated. As shown in FIG. 4F, the dimension of the minute piece 205 is 14 μm × 16 μm × 10 μm. However, the height is 10 μm. The depth from the surface of the V-grooves 201 and 202 is equal to the height of the minute piece 205 and is 10 μm, but the actual processing depth is required to be at least 14 μm. Here, an extra 3 μm is excavated, and the processing depth is d = 14 μm. The width setting value w and depth setting value H of the V-grooves 201 and 202 are w = 2 μm and H = 15 μm from the equation (5). Similarly, the processing depth of the V groove 203 is d = 17 μm. Similarly, the set value w for the width and the set value H for the depth of the V-groove 203 are w = 2 μm and H = 15 μm from the equation (5).

  The processing length of the V grooves 201 and 202 is L = 14 μm, and the processing length of the V groove 203 is L = 16 μm. From the equation (3), the processing time of the V grooves 201 and 202 is 78 s, and the processing time of the V groove 203 is 89 s, respectively.

  The processing time of the V groove 204 is the same as the processing time of the V groove 203 and is 89 s. Therefore, the processing time required for sampling a micro piece having an isosceles triangular cross section is (78 s + 89 s) × 2 = 334 s. That is, about 5.6 minutes. Here, the case of processing with a beam current of 20 nA has been described. When the beam current is about 10 nA, the processing time is about doubled to about 11 minutes.

  According to this example, since a small piece is cut out from the wafer only by the V-groove processing, there is little possibility that a problem due to redeposition (hereinafter referred to as redeposition) occurs. Redepo is a phenomenon in which sputtered particles accumulate on sidewalls that are not irradiated with a beam. In the V-groove processing, since scanning is repeatedly performed between two narrow side walls at a short cycle, the redeposit is formed on the side wall and is sputtered soon, so that the redepot is hardly formed on the side wall. In the case of the example in FIG. 2, redeposition does not occur in the formation of the first two V grooves 101 and 102. However, by forming the next V grooves 103 and 104, the first two V grooves 101 and 102 are filled with the redepot. However, in this example, only the positions of the V grooves 101 and 102 that intersect with the V grooves 103 and 104 are filled with the redepot. Therefore, it is easy to remove the redepot in this part.

  The redepo is removed in a state where the sampling probe 12 is adhered to the minute piece 105 and before the minute piece 105 is completely separated. The beam current for redepo removal is about 10 nA. When the beam current is large, the periphery is processed by the removal of the redepot, and a redepot is generated.

  According to this example, since a minute piece is cut out from the wafer only by V-groove processing, the processing time is shorter than in the case of performing conventional rectangular cross-section groove processing. When V-groove processing is not used and a minute piece of the same size is cut out by a groove having a normal rectangular cross section, the processing time is required to be several tens of minutes because the processing volume is large even if the beam current is 30 nA.

  According to the present invention, an ion beam inclined with respect to the normal line of the sample was used to form the V groove. According to the present invention, the charged particle beam apparatus may have any structure as long as it can generate an ion beam inclined with respect to the normal line of the sample. In the example of FIG. 1, the charged particle beam apparatus includes an FIB column 20 having an optical axis inclined with respect to the z axis of the stage 42. However, instead of providing the tilted FIB column 20, a stage having a function of tilting the sample may be used.

  In the above-described example, an ion beam inclined by 45 degrees with respect to the normal line of the sample is used. However, an ion beam inclined by another angle with respect to the normal line of the sample may be used. For example, an ion beam inclined by 30 degrees or 60 degrees with respect to the normal line of the sample may be used.

  According to the present invention, since a minute piece can be sampled from a sample only by V-groove processing, sampling processing can be performed with one processing beam. That is, from the start to the end of processing, the set value w for the width of the V groove and the set value H for the depth are constant. Further, according to the present invention, when a desired depth d is given in the V-groove processing, the set value H for the depth of the V-groove and the set value W for the width are obtained so that the processing time is minimized. Therefore, the V-groove can be processed easily and efficiently. Further, in the V-groove processing, since the processing volume is smaller than that of the rectangular groove, sampling can be performed in a short time even if the beam current is small. Furthermore, according to the present invention, in an apparatus having a column inclined with respect to the wafer, it is possible to sample a minute piece including a defect without dividing the wafer only by using the rotation function of the stage once, which is suitable for sampling automation.

  The example of the present invention has been described above, but the present invention is not limited to the above-described example, and various modifications can be made by those skilled in the art within the scope of the invention described in the claims. It will be easily understood if there is.

It is a figure which shows the structural example of the charged particle beam apparatus by this invention. It is explanatory drawing for demonstrating the method to cut out a micro piece sample with the P-shaped V-groove by this invention. It is a figure which shows the state which made the probe adhere | attach the micro piece in the processing method by this invention. It is explanatory drawing for demonstrating the method to cut out a micro piece sample by the square-shaped V groove by this invention. It is a figure for demonstrating the level | step difference of the sample surface produced by beam scanning. It is a figure which shows the incident angle dependence of sputtering yield. It is a figure which shows the relationship of the depth d of the V groove actually formed with respect to the setting value H of the depth of a V groove, and the setting value W of a width | variety.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Sampling manipulator, 11 ... Probe position control, 12 ... Sampling probe, 20 ... Focused ion beam (FIB) column, 21 ... Ion gun, 22 ... Beam limiting aperture, 23 ... Lens system, 24 ... Deflector, 25 ... Ion beam, 30 ... depot gun, 31 ... nozzle, 32 ... nozzle position / temperature control, 33 ... depot source reservoir, 40 ... wafer, 41 ... wafer holder, 42 ... stage, 43 ... vacuum exhaust device, 45 ... charged particle detector

Claims (12)

Inputting a desired depth of the V-groove, calculating a set value of the V-groove depth and a set value of the width of the V-groove from the desired depth so as to minimize the processing time, Irradiating the surface of the sample with a focused ion beam based on a set value to form a V-groove on the surface of the sample, and cutting out a micro-piece from the surface of the sample by repeating the formation of the V-groove. , only contains the depth d of the V-groove, the width w of the V groove, the length of the V grooves L, sputtering yield material Y (0), controls the processing time t from the beam current Ib by using the following formula And a focused ion beam processing method.

2. The focused ion beam processing method according to claim 1, wherein the set value H of the depth of the V groove and the set value w of the width of the V groove are calculated from a desired depth d of the V groove using the following empirical formula. And a focused ion beam processing method.
w = 0.115d
H = 0.115e ² d   The focused ion beam processing method according to claim 1, wherein the minute piece is cut out only by V-groove processing.   2. The focused ion beam processing method according to claim 1, wherein the V-groove is processed by using an ion beam inclined at a constant angle with respect to the normal line of the sample. .   2. The focused ion beam processing method according to claim 1, wherein the set value is constant until the minute piece is cut out, and the state of the focused ion beam is constant.   2. The focused ion beam processing method according to claim 1, wherein the minute piece is cut out by forming the V-groove along a P-shape.   2. The focused ion beam processing method according to claim 1, wherein the minute piece is cut out by forming the V-groove along a square shape.   2. The focused ion beam processing method according to claim 1, wherein the sampling probe is adhered to the minute piece before or after the minute piece is cut out from the surface of the sample, and the minute piece is held by the sampling probe. A method of processing a focused ion beam, comprising: completely cutting off a minute piece. From a stage for moving the sample in a desired axial direction, a charged particle beam column for irradiating the sample with a charged particle beam, a control unit for controlling the charged particle beam column, and a desired depth of the input V-groove, A calculation unit for calculating a set value of the V-groove depth and a set value of the width of the V-groove so as to minimize the processing time;
The control unit forms a V groove on the surface of the sample by irradiating the surface of the sample with the focused ion beam based on the set value calculated by the calculation unit, and repeats the formation of the V groove. to cut out a small piece from the surface of the sample,
The calculation unit controls the processing time t from the depth d of the V groove, the width w of the V groove, the sputtering yield Y (0) of the material, and the beam current Ib using the following expression. Particle beam device.

10. The charged particle beam apparatus according to claim 9, wherein the calculation unit calculates a set value H for the depth of the V groove and a set value w for the width of the V groove from the desired depth d of the V groove by the following empirical formula Charged particle beam apparatus characterized by calculating using
w = 0.115d
H = 0.115e ² d 10. The charged particle beam apparatus according to claim 9, wherein the charged particle beam is irradiated from a direction inclined at a constant angle with respect to a normal line of the sample. 10. The charged particle beam apparatus according to claim 9 , wherein a sampling manipulator having a sampling probe is provided, and the sampling probe is adhered to the minute piece before or after the minute piece is cut out from the surface of the sample. Particle beam device.

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