JPH09259810A - Method for analyzing object using focusing ion beam device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for analyzing an object using a focusing ion beam device capable of easily checking the state of a particular position and responding to any variation in a machining range. SOLUTION: An ion beam radiation part 3 repeats sectional area machining and sectional area observation at a particular position of a semiconductor element 1 on a finely moving stage 2 at a constant interval. Namely, when the initial section is formed, the finely moving stage 2 inclines the semiconductor element 1 and the ion beam radiation part 3 scans this sectional area by means of an ion beam. A control part 61 creates a sectional area image data on the basis of the signal of a detector 4 and stores in a memory part 62 together with position data. Thereafter, the semiconductor element 1 is returned in its position before its inclination and the next sectional area machining is started. When all of machining and observation are completed, a ternary data display processing part 63 displays a particular position cubically from each sectional surface image data and the position data stored in a ternary data storing part 62.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for analyzing and observing a specific portion of an object to be observed such as a semiconductor element by an ion beam in a focused ion beam apparatus and then observing the object.

[0002]

2. Description of the Related Art A focused ion beam apparatus is a method for irradiating an irradiation target such as a semiconductor element with an ion beam.
At the ion beam irradiation position of the irradiation object, the surface shape can be observed, fine processing can be performed by the sputter etching method, or a metal film can be formed. As a result, the focused ion beam apparatus is capable of correcting the wiring of the semiconductor element and observing the cross section of a specific portion, and has become an indispensable apparatus for recent failure analysis of the semiconductor element.

In the conventional analysis method using the focused ion beam apparatus, first, a semiconductor element is set on a fine movement stage provided in the focused ion beam apparatus, the surroundings are evacuated, and the ion beam is applied to the semiconductor element. Set up the focused ion beam device until it is ready to scan. Next, a certain area on the semiconductor element is scanned with an ion beam, so that secondary electrons or secondary electrons emitted from the surface of the semiconductor element are scanned.
Detect secondary ions. Further, based on the detection result, image processing is performed using a computer or the like, and a SIM image showing the surface shape of the area is displayed on the monitor. The SIM image is displayed each time the fine movement stage is moved, and the fine movement stage is aligned so that a specific portion, which is an analysis portion, can be displayed.

In the focused ion beam apparatus, when observing a cross section formed at a specific portion of a semiconductor element, the ion beam is obliquely scanned with respect to the semiconductor element to observe a desired cross section. Therefore, as shown in FIG. 18, at the time of observing a cross section, it is necessary to form a cross section at a specific portion 71 of the semiconductor element and remove a region that obstructs the visual field by sputtering. The processing area 72 is determined by the depth of the cross section and the angle of observation.

Therefore, the user, for example, using a keyboard or the like, conditions of cross-section processing such as etching or deposit on the SIM image displaying the specific portion 71 as shown in FIG. 18A. As the setting, the processing area 72, the processing (etching) time, and the current value of the ion beam are designated.

The processing area 72 has a relatively wide area in order to secure a field of view necessary for observation, and it is necessary to form a large hole by sputtering the processing area 72 using an ion beam having a low current value. It takes time. On the other hand, when the current value of the ion beam is increased, the cross section becomes dirty due to variations in the aperture and current value of the ion beam, etching due to overlapping of sputtering, and the like, which hinders observation of the cross section. Therefore, the focused ion beam device performs roughing for increasing the current value of the ion beam to the order of several nA to roughly perform the rough processing, and then lowers the current value of the ion beam to the order of several pA for the finishing processing. And, a clean cross section is obtained in a short time.

The roughing process is completed several μm before the cross section 73 so that the desired cross section 73 is not accidentally cut. As a result, as shown in FIG. 18B, a space for securing a visual field is secured. Further, the cross-section 74 formed by the rough processing has become dirty due to the above etching and the like. Then, as shown in FIG. 18C, finish processing is performed to clean the dirty cross section 74 and remove the remaining area. As a result, a desired cross section 73 is formed at the specific location 71.

When the cross-section processing is completed, generally 60 °
The semiconductor element is tilted in the range up to. Further, the current value of the ion beam is lowered to the order of several pA, and the ion beam diameter of the ion beam is narrowed down to the minimum. With this ion beam, the cross section 73 of the tilted specific portion 71 is scanned to obtain a SIM image. Further, after performing image processing using a computer or the like, as shown in (d) of FIG. 18, the column name shape is displayed on a monitor or the like. Since the ion beam current value is low, the cross section can be observed without damaging the ion beam.

[0009]

However, each of the above-mentioned conventional observation methods has a problem that only a planar cross-sectional image can be displayed. In general, a semiconductor element that is a target of cross-section observation has a three-dimensional three-dimensional structure, and therefore information obtained from the cross section of only one plane is limited. Further, since the cross-sectional image obtained varies depending on the processing location, it is extremely inconvenient to observe one plane.

For example, as shown in FIG. 19A, when a dust defect occurs in a specific portion 71, a cross section 73a
Like 73 to 73c, the information such as the shape and position of the dust, and in which layer of the semiconductor element the dust is formed differs depending on the place where the cross section 73 is formed. Further, as shown in FIG. 19B, in the case where a current leakage portion is formed in the specific portion 71, the cross sections 73d to 7d are formed.
In the cross-sectional image obtained by observing 3f, it is difficult to judge the defect occurrence situation and specify the defect occurrence location.

Further, in order to change the place of observation, it is necessary to specify the position and form a new cross section 73. Therefore, there is no problem in forming the cross sections in the order of the cross sections 73d to 73f.
As a result of observing f, especially other cross-sections 7 such as the cross-section 73g.
It is not possible to observe cross sections that have already been cut, such as cross sections that intersect with 3 and between each cross section.

In addition, the above method is easily affected by variations in the ion beam diameter of the ion beam and the current value, and it becomes difficult to obtain a desired cross section as the observation target becomes minute. Also, when observing the cross section, tilting the semiconductor element and returning it to the original position for processing again,
Precise alignment becomes difficult when setting backlash and processing conditions for the fine movement stage.

In order to solve this problem, for example, in Japanese Unexamined Patent Publication (Kokai) No. 4-188553, processing by an ion beam and surface observation are performed at the same time, and plane images parallel to the surface of the semiconductor element are sequentially acquired. A method of accumulating as three-dimensional image data and obtaining an arbitrary cross section by image conversion is disclosed.

In this method, a SIM image of the surface of the semiconductor element is acquired in the same manner as the above-mentioned cross-section observation method. Further, as shown in (a) of FIG. 20, a processing region 72a is set so as to cover the specific portion 71, the processing time of the processing region 72a, the ion beam diameter of the ion beam used for the processing, and the current value. Is specified.

Then, the focused ion beam apparatus scans the processing area 72a in steps in the X and Y directions at regular intervals. Since the amount of sputtering is determined by the material of the semiconductor element, the type of ion beam (difference in ion beam current value), energy, dose, etc.,
As shown in FIG. 20B, the processing region 72a is dug to a substantially constant depth by one scanning. Further, in response to scanning, all detection signals of secondary electrons and secondary ions are stored in the storage device, and X, Y at the specific location 71 are stored.
Acquire the plane image data of the direction. Therefore, by repeating the scanning, the planar images of the internal layers are sequentially stored in the storage device.

As a result, as shown in FIG.
At the stage where the processing has proceeded to the depth to be observed, the planar images of all layers are stored in the storage device. In each plane image, the step in the depth direction is proportional to the number of scans. Therefore, as shown in FIG. 21, by overlapping the plane images obtained by each scan in the order of the number of scans, X, Y,
And three-dimensional image data in the Z direction.

In response to a user's instruction, the control computer extracts, for example, data having the same X-direction address from the three-dimensional image data and displays them side by side in the Y-direction and the Z-direction. As a result, as shown by the broken line in FIG. 21, it is possible to obtain an arbitrary sectional image parallel to the Y direction. By the above method, the focused ion beam apparatus can reproduce a cross-sectional image at any position and at any angle from the accumulated planar image data.

However, even in the above method, the displayed image is a plane cross-sectional image with limited information, which is the same as in the case of the cross-sectional observation method described above. In addition, the cross-sectional image cannot be obtained unless the position of the cross-section is specified. Therefore, for example, 73d to 73 shown in FIG.
When the position of the cross section is mechanically designated like f, it is necessary to confirm that a defect has occurred from these cross-sectional images and to designate the position of the cross section 73g suitable for confirming the defective portion and the defective situation. is there. Therefore, it is still difficult to identify the defective situation and the defective portion.

In addition, in this method, since the processing and the observation of a specific portion are performed at the same time, the ion beam current value of the ion beam becomes large, and the accuracy at the time of observation deteriorates. Further, for normal observation, the ion beam diameter of the ion beam and the ion beam current value cannot be changed during processing. Furthermore, in order to see the lower layer, it is necessary to delete the upper layer. Therefore, the planar size of the processed region 72a cannot be changed according to the depth. As a result, holes are formed in the entire processed region 72a with a constant depth, and there is a risk that parts not related to defective parts may be undesirably cut.
As a result, a new problem arises that it becomes difficult to analyze the influence of the defective portion on other layers constituting the semiconductor element.

The present invention has been made in view of the above problems, and an object of the present invention is to analyze an object to be observed of a focused ion beam apparatus that can easily confirm the condition of a specific place and can cope with a change in a processing region. To provide a method.

[0021]

According to a first aspect of the present invention, there is provided a focused ion beam apparatus for observing an object under observation, in which a desired position of the object under observation is irradiated with an ion beam. , A cross-section processing step of cross-section processing, and in the cross-section processing step, the cross section formed on the object to be observed is scanned with an ion beam to detect charged particles emitted from the object to be observed,
The following steps are provided in the observed object analysis method of the focused ion beam apparatus, which has an observation step of acquiring cross-sectional image data of the cross-sectional surface.

That is, with respect to a specific portion of the observed object,
An accumulation step of repeating the cross-section processing step and the observation step with a predetermined interval, and accumulating position data indicating a position where a cross section is formed in each cross-section processing step and cross-sectional image data in each observation step, and the accumulation step. And a display step of three-dimensionally displaying the shape of the specific portion from each cross-sectional image data and position data accumulated in.

The storage step is realized, for example, by storing the sectional image data and the position data in a storage device such as a semiconductor memory or a disk device.
Further, in the display step, for example, pixels forming each cross-sectional image data stored in the storage device by an arithmetic processing device such as a computer are arranged along a three-dimensional orthogonal coordinate system, for example, contour extraction or hidden line processing. It is realized by performing various image processing such as.

By performing each of the above steps, the focused ion beam apparatus can stereoscopically display a specific location. Therefore, as compared with the conventional planar display method, it is easier to grasp the defective state of a specific portion and the entire appearance of the defective portion. Furthermore, even when gazing at a specific cross section, it is easy to specify the cross section.

In addition, unlike the conventional cross-section observation method, cross-sections at arbitrary angles can be formed by mechanically forming cross-sections and converting the observed data of each cross-section without designating each desired cross-section. Can be obtained. Therefore, it is not necessary to change the cross section to be formed according to the defective state of the specific portion.
As a result, automatic observation of a specific location can be realized relatively easily.

Further, unlike the conventional method of reproducing a cross-sectional image from a plane image, the regions to be irradiated with the ion beam are different from each other in each processing step. Therefore, even if an error occurs at each processing, the error is not accumulated,
It can be easily corrected. As a result, the accuracy of observation can be improved as compared with the conventional analysis method.

Further, according to a second aspect of the present invention, there is provided a method for analyzing an object to be observed in a focused ion beam apparatus according to the first aspect of the invention, wherein the depth of the cross section to be formed from the surface in the cross section processing step is the same. The feature is that each can be set separately.

The depth of the cross section can be individually set by changing the irradiation time of the ion beam in the one cross section processing step or by setting the ion beam irradiation time separately between the cross section processing steps. Can be set.

Therefore, for example, even when there is a region that is not desired to be processed below a specific place, for example, when analyzing the influence on the other layers of the semiconductor element, etc., avoid the region and cross section. The processing area of the processing process can be set. Therefore, as compared with the conventional method of reproducing a cross-sectional image from a plane image, it is possible to automatically observe even a specific portion having a more complicated shape. As a result, it becomes easy to analyze the relationship between the specific location and the surrounding locations.

Further, in the method of analyzing an observed object of a focused ion beam device according to a third aspect of the present invention, in the configuration of the invention of the first or second aspect, the ion beam aperture of the ion beam with which the object to be observed is irradiated. At least one of the ion beam current value and the ion beam current value is set differently in the observation step and the cross-section processing step.

Therefore, the object to be observed can be scanned with an ion beam suitable for each process. As a result, the accuracy at the time of observation can be further improved as compared with the conventional analysis method.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention.
It is as follows when it demonstrates based on FIG.
That is, the focused ion beam apparatus to which the method for analyzing an observed object according to the present embodiment is applied is for irradiating an observation object such as a semiconductor element with an ion beam to process the semiconductor element or to observe the surface thereof. Is used for.

As shown in FIG. 1, the focused ion beam apparatus has a fine movement stage 2 for fixing a semiconductor element 1, an ion beam irradiation section 3 for irradiating the semiconductor element 1 with an ion beam, and a semiconductor element for emitting an ion beam. A secondary electron / secondary ion detector (hereinafter, abbreviated as a detector) 4 for detecting secondary electrons or secondary ions generated when irradiated to 1
And a control circuit unit 5 for controlling each of the above units. Furthermore, various conditions are set in the control circuit unit 5 based on the information from the control circuit unit 5, and the cross-sectional image data is created and accumulated based on the detection result of the detector 4 to perform three-dimensional display control. A computer 6 and a monitor 7 and a keyboard 8 which are input / output devices of the control computer 6 are provided.

Thus, as shown in FIG. 2, the focused ion beam apparatus can perform the following three processes. First, the first process is shape observation, and the ion beam irradiation unit 3 shown in FIG. 1 uses a submicron-focused ion beam to irradiate the surface of the semiconductor element 1 with the ion beam, as shown in FIG. To scan. At this time, the detector 4 detects secondary electrons or secondary ions emitted from the surface of the semiconductor element 1 by the irradiation of the ion beam. Further, after being subjected to A / D conversion and amplification processing by the control circuit unit 5 shown in FIG. 1, the control computer 6 performs image processing and displays the surface shape of the semiconductor element 1 on the monitor 7. Thereby, the user can observe the surface shape of the semiconductor element 1. An image observed by the focused ion beam device is generally a SIM (Scanning Ion Microsci).
oe: Scanning ion microscope) image.

The second processing is fine processing by the sputter etching method, and as shown in FIG. 2B, the ion beam irradiation unit 3 locally scans the semiconductor element 1 with the ion beam. As a result, the atoms and molecules on the surface of the semiconductor element 1 are repelled into the vacuum. The focused ion beam apparatus can process the semiconductor element 1 with submicron accuracy by etching applying this sputtering phenomenon. As a result, it is possible to perform pattern modification such as punching of the protective film 1a formed on the semiconductor element 1 or cutting of the metal wiring 1b.

The third process is a metal film forming process. As shown in FIG. 2C, the gas gun 9 provided in the focused ion beam apparatus blows a raw material gas, which is a raw material of the metal film 1c, onto the surface of the semiconductor element 1 to adsorb it. afterwards,
The ion beam irradiation unit 3 shown in FIG. 1 scans a desired range with an ion beam. As a result, only the scanned portion undergoes a chemical reaction, and the metal film 1 is formed on the desired portion of the semiconductor element 1.
c can be formed.

By performing the above-mentioned three processes depending on the application, the focused ion beam apparatus can correct the wiring of the semiconductor element 1 or can observe a cross section at a specific place.
As a result, the semiconductor device 1 can be corrected and the defect can be analyzed.

Before describing each of the above parts in more detail, for convenience of description, the directions are defined as follows. That is,
As shown in FIG. 3A, the ion beam traveling direction and the depth direction of the semiconductor element 1 are set in the Z direction with reference to the case where the traveling direction of the ion beam and the surface of the semiconductor element 1 are orthogonal to each other. , Orthogonal to this and orthogonal to each other 2
Let the directions be the X and Y directions, respectively. In addition, when observing the surface of the semiconductor element 1, the Y direction is referred to as a downward direction.
Further, as shown in (b) and (c) of FIG. 3, since the X, Y, and Z directions of the two do not match at the time of cross-section observation,
When it is necessary to make a distinction, the direction based on which is specified is designated each time.

As shown in FIG. 3, the fine movement stage 2 has a mounting surface 2a on which the semiconductor element 1 is mounted.
For example, the semiconductor element 1 can be fixed on the mounting surface 2a with a conductive tape or a conductive paste. Further, the fine movement stage 2 can be operated in the XY and Z directions, or tilted and rotated with high accuracy of ± 0.05 μm. Therefore, wherever the specific portion 11 to be analyzed is located in the semiconductor element 1, the fine movement stage 2 can guide the specific portion 11 to the scanning position of the ion beam.

When the center point 12 of the specific location 11 is not located at the center of the fine movement stage 2, when the semiconductor element 1 is tilted, the position and height of the specific location 11 change before and after the tilt. Therefore, as shown in FIG. 3A, even when the ion beam is correctly focused on the center point 12 in a state where the mounting surface 2a of the fine movement stage 2 is orthogonal to the traveling direction of the ion beam, As shown in FIG. 3B, when the semiconductor element 1 is tilted, the focus position and irradiation position of the ion beam deviate from the specific portion 11. As a result, the specific portion 11 cannot be correctly observed and processed. In order to prevent this change, it is necessary to correct the position of the fine movement stage 2 in the X, Y and Z directions as shown in FIG. In addition, in FIG. 3, the tip of the broken line arrow indicating the ion beam indicates the focused position of the ion beam.

The fine movement stage 2 according to this embodiment has a eucentric mechanism (not shown) for position correction. As a result, the focus is focused on the specific portion 11 in the pre-inclination state and the post-inclination state, and the correction values ΔX, ΔY, and ΔZ in both states are set in the X, Y, and Z directions, respectively, to thereby perform the fine movement. The position of the stage 2 can be automatically corrected before and after the inclination. In FIG. 3C, ΔX is not shown because the correction in the X direction is unnecessary.

The ion beam irradiation unit 3 shown in FIG.
Is an ion source 31 for generating an ion by converting an ion source material into plasma, an extraction electrode 32 for extracting an ion beam from the ion source 31, an electrostatic lens 33 and an objective lens 36 for converging the extracted ion beam. ,
A blanking electrode 34 interposed between the two lenses 33 and 36 for switching the path of the ion beam as necessary.
Further, an aperture 35 for selecting the ion beam diameter and the ion beam current value of the ion beam, an astigmatism correction lens 37 arranged after the objective lens 36 for correcting the ion beam shape of the ion beam, and shaped ions The semiconductor element 1 is provided with a deflection electrode 38 for scanning the ion beam by deflecting the beam in the XY directions.

The aperture 35 can change the ion beam diameter and the ion beam current value by, for example, limiting the passage of the ion beam. The ion beam irradiation unit 3 according to the present embodiment has the following Table 1 and
As shown in FIG. It has a five-stage aperture 35 of 0-4.

[0044]

[Table 1]

Each aperture 35 is an aperture N
o. The lower the number, the larger the ion beam diameter and the higher the ion beam current value are set. As a result, the processing speed becomes faster when the aperture having a lower number is used, and the semiconductor element 1 can be processed more finely when the aperture having a higher number is used. Therefore, the aperture No. 0 to 2 are mainly
Used for rough machining of the semiconductor element 1, the aperture No.
3 and 4 are used for finishing.

Further, the aperture No. 4 is also used in the observation mode. In the ion beam irradiation unit 3, the change to the observation mode is performed by a focusing lens control circuit 52, which will be described later, provided in the control circuit unit 5. In the ion beam irradiation unit 3 according to the present embodiment, the lenses 33, 36, and 37 that focus the ion beam are electrostatic lenses.
The focusing lens control circuit 52 uses the lenses 33, 36,
The ion beam is narrowed down by changing the voltage applied to 37. As a result, the ion beam irradiation unit 3
An ion beam having an extremely fine and low current value can be obtained, and the focused ion beam device can observe the semiconductor element 1 with high resolution without damage.

On the other hand, the control circuit section 5 has an ion source control circuit 51 for controlling the voltages applied to the ion source 31 and the extraction electrode 32, an electrostatic lens 33 for focusing the ion beam,
A focusing lens control circuit 52 that controls the objective lens 36 and the astigmatism correction lens 37, and a deflection control circuit 53 that controls the deflection electrode 38 are provided. Furthermore, the detector 4 is controlled, and the detector control circuit 54 that amplifies the detection signal from the detector 4 and converts it into a digital value, and the fine movement stage 2 are controlled, and the semiconductor element 1 and the ion beam A stage control circuit 55 for adjusting the positional relationship is provided.

Further, the control computer 6 receives a detection signal from the detector 4 via the detector control circuit 54 to form sectional image data and, for example, an instruction from the keyboard 8 or In order to three-dimensionally display the control unit 61 that sets various conditions in the control circuit unit 5 based on the cross-sectional image data, the storage unit 62 that stores the combination of the cross-sectional image data and the position data, and the specific portion 11 In addition, the cross-sectional image data and the position data accumulated in the storage unit 62 are converted to display a stereoscopic image on the monitor 7.
And a three-dimensional data display processing unit 63 for displaying. The storage unit 62 is realized, for example, as a region of a storage device such as a semiconductor memory or a disk device, and the control unit 61 and the three-dimensional data display processing unit 63 are, for example, CP.
U (Central Processing Unit) is a functional block realized by executing a predetermined program.

The control section 61 receives all detection signals from the detector 4 converted into digital values by the detector control circuit 54. The detection signal changes according to the scanning position of the ion beam, that is, the deflection direction of the ion beam. Therefore, by synchronizing the deflection direction and the detection signal, the surface shape and material of the semiconductor element 1 at each scanning position of the ion beam can be detected. The control unit 61 can reconfigure these according to the scanning position and display the image data of the surface of the semiconductor element 1 on the monitor 7.

Further, with respect to the image data, image processing such as contour extraction due to a change in luminance is performed, and the size and position of a characteristic portion on the surface of the semiconductor element 1 such as a hole formed by an ion beam can be recognized. . Thus, it is possible to determine whether the fine movement stage 2 has the semiconductor element 1 arranged at a desired position or whether a hole having a desired size has been formed in the semiconductor element 1 by the ion beam. further,
The control unit 61 can control the fine movement stage 2 and the ion beam irradiation unit 3 via the control circuit unit 5 according to a user's instruction input from the keyboard 8 or the like or the above determination result.

The storage unit 62 stores, for example, a pair of data by combining position data composed of position coordinates of a cross section and the cross sectional image data stored in the scanning order of the pixels forming each cross sectional image data. it can. The storage unit 62 is provided with a plurality of regions for storing this data, and the above-mentioned data corresponding to each cross section formed at the specific location 11 of the semiconductor element 1 is stored, for example, in the order of position data. it can.

The three-dimensional data display processing unit 63 is also provided.
Is an arbitrary X, Y, from the data stored in the storage unit 62.
It is possible to read the pixel data of the Z coordinate and display a stereoscopic image viewed from a desired viewpoint on the monitor 7. Although various methods are conceivable as the display method, in the present embodiment, as shown in FIG. 17, which will be described later, for example, the contour is extracted from adjacent pixel data, and the front-back relationship of the contour is determined. , The hidden part is shown by a broken line.

The operation of each part of the focused ion beam apparatus in the case of analyzing a specific portion of the semiconductor element 1 according to the three-dimensional cross-sectional analysis method in the above-mentioned structure will be described with reference to FIGS. The following is a description of each step. The cross-sectional three-dimensional analysis method according to the present embodiment includes a step of setting up the ion beam irradiation unit 3 including steps 1 (hereinafter, abbreviated as S1) to S5, and steps S6 to S9.
The setting and adjusting step before machining consisting of S10 to S12 and the setting step of machining conditions consisting of S10 to S12.
A sectional image data accumulating step (accumulating step) consisting of 20;
It can be divided into a three-dimensional image display step (display step) including S21 and S22.

First, in the setup process consisting of S1 to S5, the setup work is carried out until the focused ion beam device is ready to be processed into the semiconductor element 1. That is, in S1, the semiconductor element 1 is placed on the fine movement stage 2.
Is fixed with conductive tape or conductive paste so that it does not move. Next, to enable irradiation of the ion beam, for example, by a vacuum pump not shown,
The path of the ion beam and the semiconductor device 1 are brought into a high vacuum state (S2).

Subsequently, in S3, the ion beam irradiation unit 3
Start up. Specifically, the ion source 31 is, for example,
The ion source material introduced into the ion source 31 is turned into plasma by arc discharge or the like. In addition, the ion source 31
A high voltage is applied between the lead electrode 32 and the extraction electrode 32.
Thereby, a high-intensity ion beam is extracted from the ion source 31 and accelerated. The electrostatic lens 33, the aperture 35, and the objective lens 36 focus the accelerated ion beam. The ion source control circuit 51, the focusing lens control circuit 52, and the deflection control circuit 53 include an ion source 31, an extraction electrode 32, an electrostatic lens 33, and an objective lens 36.
The voltages applied to the astigmatism correction lens 37 and the deflection electrode 38 are controlled. Thereby, the ion beam irradiation unit 3 can always irradiate a stable ion beam.

Further, in S4, the deflection control circuit 53
Controls the voltage applied to the deflection electrode 38 to deflect the focused ion beam in the XY directions. This allows
The ion beam is applied while scanning the surface of the semiconductor element 1. When the semiconductor element 1 is scanned with an ion beam, secondary electrons and secondary ions are emitted based on the surface shape and material distribution of the semiconductor element 1. Detector 4
Detects the emitted secondary electrons and secondary ions.
The detector control circuit 54 amplifies the detection signal of the detector 4,
It is A / D converted and sent to the control computer 6. The control computer 6 recognizes the surface shape of the semiconductor element 1 based on the received signal and displays it on the monitor 7. It should be noted that if the ion beam is continuously scanned for a certain period of time, the sputtering on the surface of the semiconductor element 1 overlaps with each other, resulting in an etching state.

Next, in S5, all the apertures 35
Are sequentially selected, the focus of the ion beam is adjusted for each aperture 35, and the adjusted focus value and ion beam current value are stored in the control computer 6. As a result, even if the aperture 35 is changed during processing, the focus can be adjusted based on the stored condition each time, and the focus of the ion beam can be constantly maintained. As a result, a stable ion beam can always be obtained, and stable and highly accurate processing can be performed even if the aperture 35 is changed.

When the focus adjustment of the ion beam is completed for all the apertures 35, the ion beam irradiation unit 3 is set to the observation mode in preparation for the subsequent step, and the aperture No. 4 aperture 35 is selected.

Subsequently, in S6 to S9 described below, setting and adjustment before processing are performed. That is, in S6,
The control computer 6 sets the X, Y, height direction, rotation, and inclination of the fine movement stage 2 via the stage control circuit 55 to determine the irradiation position of the ion beam on the semiconductor element 1. Further, the control computer 6
Similarly to S4, the surface shape of the semiconductor element 1 at the irradiation position of the ion beam is displayed on the monitor 7. While observing the surface shape, the user uses the keyboard 8 to instruct a new position of the fine movement stage 2 to search for a specific position on the semiconductor element 1. Thereby, the semiconductor element 1
The fine movement stage 2 in which is fixed is guided to a desired position.

Next, the control computer 6 displays the cross line 13 on the monitor 7, as shown in FIG. The user finely adjusts the position of the fine movement stage 2 so that the intersection 14 of the cross line 13 coincides with the specific position, and performs the alignment (S7). Further, in S8, as shown in FIG. 7, the surface of the semiconductor element 1 around the specific portion 11 is provided with four markings 12 serving as reference points in each processing.
Specifically, the aperture No. 2 aperture 35
Around the specific point 11 and each cross line 13
The ion beam is focused on and irradiated for several tens of seconds.
By this spot processing, a circular hole having a depth of about several μm is dug in the semiconductor element 1. The distance between the specific portion 11 and each marking 15 is set so as not to affect the observation of the specific portion 11.

Then, in S9, the eucentric mechanism is adjusted. First, as shown in FIG.
The mounting surface 2a of the fine movement stage 2 is in a flat state, and
The control computer 6 controls the position coordinates of the fine movement stage 2 such as X, Y, and height position in a state where the ion beam is accurately focused on the center point 12 of the specific place 11.
To memorize. Next, the mounting surface 2a is moved to an arbitrary angle (for example,
Tilt to 60 °). Since the specific portion 11 is not always located at the center of the fine movement stage 2, the irradiation position and the focus position of the ion beam deviate from the specific portion 11 due to the inclination, as shown in FIG. In this state, the X, Y and height positions of the fine movement stage 2 are adjusted while observing the surface shape of the semiconductor element 1 as in S6 and S7, and as shown in FIG. Specific place 1
The ion beam is refocused to 1. The control unit 61 stores the position coordinates of the fine movement stage 2 at the time of focusing,
The correction values ΔX, ΔY, and ΔZ at the time of tilt are calculated and set in the stage control circuit 55.

As a result, the eucentric mechanism of the fine movement stage 2 can be adjusted, and the focus position of the ion beam can be made to follow the specific position 11 regardless of whether or not it is tilted. As a result, the center point 12 of the specific place 11
Is always displayed at the intersection 14 of the cross line 13 on the monitor 7.

Following the above settings and adjustments before processing, various processing conditions are set in S10 to S12 described below. That is, in S10, as shown in FIG. 7, the fine movement stage 2 is set in a flat state, and the specific portion 11 is displayed at the intersection 14 of the cross line 13. Further, the surface image data in this state is stored in the control computer 6. The surface image data and the position coordinates of the fine movement stage 2 stored in S9 serve as a reference for drift correction during cross-section processing, which will be described later.

Next, in S11, the user gives an instruction to the control computer 6 by using, for example, the keyboard 8 or the like, and as shown in (a) of FIG. The range 16 is set. When the control computer 6 recognizes the slice processing range 16, as shown in (b) of FIG.
Automatically enlarges and displays the slice processing range 16 around the cross line 13 on the monitor 7 screen.

Further, the user has the slice processing range 16
For, input an arbitrary number of slice processing. The control computer 6 displays the slice lines 17 ... Which divide the slice processing range 16 in the Y direction based on the input. As a result, the slice processing range 16 is divided by the slice lines 17 ...
Then, the depth d required for cross-sectional observation is designated in μm. Since the semiconductor element 1 has a laminated structure and the film thickness changes depending on the manufacturing process, the required depth d is investigated in advance and the value is specified.

In the display example shown in FIG. 8B, the length of the slice processing range 16 in the Y direction is set to 1.6 μm. Therefore, when 16 is input as the slice processing number, the distance between the adjacent slice lines 17, that is, the width of the slice processing frame 18 becomes 0.1 μm. In addition, in this embodiment, as shown in FIG.
The depth d was set to 3 μm so as to reach the semiconductor substrate 1d.

Next, in S12, the control computer 6 calculates the position of the step processing frame 21 from the condition designated in S11. Specifically, when observing a cross section, it is necessary to irradiate the cross section with an ion beam, so that a space for securing a visual field is required as shown by a broken line in FIG. The width x of the opening of the space along the surface of the semiconductor element 1 and in the direction away from the cross section is calculated from the observation angle, that is, the inclination angle θ of the fine movement stage 2 and the depth d as follows: As shown in 1), x = tan (θ) × d (1) For example, when observing a cross section with a depth d of 3 μm at 60 °, the width x of the opening is 5.2 according to the above formula (1).
μm is required.

In the present embodiment, as shown by the solid line in FIG. 9, in order to shorten the processing time, the step processing trace 20 is formed stepwise to secure the above space. further,
As the slicing range 16 is approached, the aperture number. The step processing trace 20 is formed while switching to the larger aperture 35. Therefore, if the step processing traces 20a to 20e are arranged in the order distant from the slice processing range 16, the step processing traces 20a will be the aperture number. With the aperture 35 of No. 0, the step processing traces 20b to 20e are respectively set to the aperture No.
It is formed by 1 to 4 apertures 35.

Therefore, the control computer 6 according to the present embodiment, for example, as shown in FIG.
Step machining frames 21a to 21e are set corresponding to 0e. Further, the processing range and processing time for each aperture 35 are determined according to the width of the slice processing range 16, the depth d, and the distance from the slice processing range 16.
The control computer 6 calculates an appropriate value and automatically sets it. In consideration of the case where a drift occurs during processing, the step processing frames 21a to 21e are set so that the adjacent step processing frames 21 each have an overlap of 10%.

When the processing conditions are set, the following S1 is performed.
In 3 to S20, cross-section processing and cross-section observation are repeated to accumulate cross-section image data. First, in S13, step processing is performed. That is, the control unit 61, for each step processing frame 21a to 21e set in S12, similarly to S14 described later, the corresponding aperture 35.
Is automatically selected, and four-point marking is aligned by changing the aperture 35. And processing time etc.
Aperture N according to the conditions specified in S12
o. From the high ion beam current value of 0, the aperture No.
Using an ion beam up to a low ion beam current value of 4,
The step processing frames 21a to 21e are sequentially processed. During processing, the entire surface is scanned at a constant cycle, and the control unit 61
Surface image data is generated from the detection signal of the detector 4, and the position coordinates of the 4-point marking are recognized. Further, the deviation of the position coordinates is obtained by comparing with the reference surface image data stored in S10. Based on this, the control unit 61
Always applies drift correction via the deflection control circuit 53. Thereby, the drift of the ion beam can be prevented to the minimum eye during processing.

Next, in S14, the current value of the ion beam is changed for the subsequent slice processing. In particular,
The control unit 61 reads out the focus adjustment and conditions stored in S5 according to the selected aperture 35, and instructs the ion beam irradiation unit 3 via the control circuit unit 5. As a result, the ion beam can be automatically changed without lowering the processing accuracy. In the present embodiment, the interval between the slice lines 17 is set to be as narrow as 0.1 μm, and the processing is performed using the aperture No. 4 observation mode. Although it depends on the observation range of the specific portion 11, the slice processing range 16 is usually 0. It is about several μm ² . Therefore, if it is not extremely wide, even if it is processed in the observation mode,
One-slice processing is completed in a short time.

After changing the ion beam to the observation mode, the focused ion beam apparatus acquires the surface image data after completion of step processing in step S15 as in step S13 as shown in FIG. Recognize position coordinates. Further, as shown in FIG. 12, the control unit 61 superimposes and displays the unprocessed reference image data.

Further, the step processing trace 20 and the semiconductor element 1
Since the shape is different from that of the surface, the difference in the detected intensity of the secondary electrons due to the surface shape is represented as a brightness level when the image data of the surface is acquired. Change according to. Note that FIG.
Indicates the case of scanning along the Y direction, and y1
Is on the end face in the Y direction of the step processing frame 21a, and y2 is
It corresponds to the opposite side end surface of the step processing frame 21e. Accordingly, the control unit 61 can determine the edge of the step processing trace 20 and can obtain the position of the cross section 19 after the step processing.

In S16, the slice processing frame 18 designated in S11 is corrected based on the position of the cross section 19 obtained in S15. If, due to the drift, an unprocessed portion or over-etching occurs and the cross section 19 is displaced from the desired position, the control unit 61 calculates the amount of displacement based on the brightness level and the surface image data of the reference. further,
Slice processing frame 1 by adding or subtracting the amount of deviation
Correct 8. As a result, as shown in FIG. 14, the slice processing frame 18 can be set at the correct position regardless of the error in the slice processing performed so far. The slice processing frame 18 is set to overlap in the X direction and the reverse X direction so as not to cause unprocessed residue in the X direction due to fluctuation of the ion beam. In addition, the slice processing frame 18
The processing time at is set according to the depth d of the slice processing frame 18 set at S12.

When the slice processing frame 18 is set, S1
In 7, the slice processing frame 18 is irradiated with an ion beam for a predetermined time to perform slice processing. During processing, full scanning is performed at a constant cycle in the same manner as step processing, and drift correction during processing is minimized because the four-point marking is read and drift correction is always performed. As a result, the first cross section 19a is formed.

When the processing of the slice processing frame 18 is completed,
Similar to S15, the reference surface image data and the processed surface image data are combined to obtain the cross-sectional position based on the difference in luminance level. Further, in a region (frame) provided in the storage unit 62 of the control computer 6 corresponding to the machining, the position coordinates of the cross-section position are stored as position data. The above S16 and S17 correspond to the cross-section processing step described in the claims.

Next, in S18, which is an observation step, the semiconductor element 1 is tilted up to 60 °. Since the eucentric mechanism of the fine movement stage 2 works, the specific portion 11 is the monitor 7
It remains visible in the center of. The control unit 61 changes the scanning speed of the ion beam to a high resolution speed,
A cross-section observation image is acquired at the speed. Further, as shown in FIG. 8B, the observation magnification is adjusted to the magnification at which the slice lines 17 ... Are displayed, and the cross-section observation image is adjusted to an appropriate brightness by auto contrast. Also, 60 °
In order to change the observation from 90 ° to 90 °, for example, magnification correction is performed on the cross-sectional observation image, and pseudo cross-sectional image data is corrected. When the correction of the cross-sectional image data is completed, the control unit 61
Stores the corrected sectional image data in the frame corresponding to the processing. When the cross-sectional image data is stored, the fine movement stage 2 returns the tilt of the semiconductor element 1.

Subsequently, it is determined whether or not the processing of all the slice processing frames 18 has been completed (S19), and the processing of S16 and subsequent steps is repeated until the processing of the last slice processing frame 18p is completed. As a result, the slice processing frames 18a to 1
Automatically repeat processing up to 8p and observation,
As shown in FIG. 5, cross-sectional image data 22 of each cross-section 19 is acquired, and each cross-sectional image data and position data are stored in each frame (a to p) provided in the storage unit 62. Note that, in FIG. 15, the cross-sectional image data 22 shown in (a) to (p) corresponds to the slice processing frames 18a to 18p, respectively, and in the case of particular distinction, the cross-sectional image data corresponding to the slice processing frame 18a. The data 22 is referred to as 22a.

When all the processing is completed (in S19, YE
In the case of S), the observation state is canceled (S20), and in S21 and S22 described below, the specific portion 11 is three-dimensionally displayed based on the cross-sectional image data and the position data.

Specifically, the control computer 6 is shown in FIG.
6, all the cross-sectional image data 22a to 22p stored in the storage unit 62 are converted into position data,
That is, they are arranged in order in correspondence with the Y coordinate. Each cross-sectional image data 22 corresponds to each cross-section 1 of the semiconductor element 1.
9 is shown, and each pixel is arranged in the X direction and the Z direction. Therefore, the three-dimensional data display processing unit 63 is made to correspond to the Y coordinate by the storage unit 62.
Therefore, for any X, Y, Z coordinates of the specific location 11,
The corresponding pixel can be read. In this way, the three-dimensional data display processing unit 63 compares each pixel with an adjacent pixel to extract contours from the thus formed three-dimensional image data, and calculates the front-rear relationship between the contours. hand,
Hidden line processing is performed (S21). As a result, the three-dimensional data display processing unit 63 displays, for example, as shown in FIG. 17, a stereoscopic image of the specific portion 11 viewed from an arbitrary viewpoint on the monitor 7.
Can be displayed (S22). Of course, it is also possible to grasp the outline of the defective portion of the specific portion 11 from this three-dimensional image and display the image of the cross section having a desired position and angle.

As described above, the focused ion beam apparatus according to the present embodiment uses, for example, the deflection electrode 38 and the like.
The ion beam irradiation unit 3 capable of scanning the ion beam in the X direction or the Y direction, and during the cross-section processing and the cross-section observation,
A fine movement stage 2 that can change the angle of the surface of the semiconductor element 1 with respect to the ion beam, a detector 4 that detects secondary electrons and secondary ions emitted from the semiconductor element 1 during scanning of the ion beam, cross-sectional image data and position. A storage unit 62 capable of storing a plurality of combinations with data, and the detector 4
The control unit 61 that forms the cross-sectional image data in accordance with the detection signal of No. 1 and stores the cross-sectional image data in the storage unit 62 together with the position data.
And a three-dimensional data display processing unit 63 that stereoscopically displays 1.

Further, using the focused ion beam apparatus, as in S16 and S17 described above, an ion beam is irradiated to each slice line 17 set at a specific position 11 at a predetermined interval to form a cross section. And a step of tilting the semiconductor element 1 on the fine movement stage 2 and scanning the formed cross section with an ion beam to form cross-sectional image data, as in S18, and the cross-sectional image data and position data. The process of storing the combination of and in the storage unit 62 is repeated, and the combinations of the sectional image data and the position data of all the slice lines 17 are accumulated in the storage unit 62. Further, as in S20 and S21, a step of analyzing the accumulated data and displaying the specific portion 11 in three dimensions is provided.

By displaying the specific portion 11 three-dimensionally, it is easy to understand the defective state of the specific portion 11 and the whole appearance of the defective portion, and it is easy to specify the specific cross-section even when gazing at the specific cross-section. Further, unlike the conventional cross-section observation method, it is possible to mechanically form a cross-section and convert the observed data of each cross-section to obtain a cross-section at an arbitrary angle without designating each desired cross-section. it can. Therefore, the cross section to be formed does not have to be changed depending on the defective state of the specific portion 11. As a result, automatic observation of the specific portion 11 can be realized relatively easily.

The three-dimensional data display processing unit 63 according to the present embodiment displays a three-dimensional image by contour extraction and hidden line processing, but the present invention is not limited to this.
When viewed from the direction of the line of sight, the pixels may be arranged in order from the back, or a method such as ray tracing may be used. Alternatively, the X, Y, and Z coordinates may be converted into another coordinate system such as polar coordinates and then processed. Three-dimensional data display processing unit 63
However, if the specific portion 11 can be displayed three-dimensionally from the data accumulated in the storage unit 62, the same effect as this embodiment can be obtained.

By the way, in the conventional method of reproducing a cross-sectional image from a plane image, since the same area is always scanned and processed, the error in the depth direction generated during the processing is accumulated. However, in the analysis method of the present embodiment, the regions irradiated with the ion beam are different from each other during each processing. Therefore, even if an error occurs during each processing, the slice processing frame 18 can be corrected each time, for example, as shown in S16. Furthermore, during processing and observation,
The area and direction of irradiation with the ion beam are different from each other. Accordingly, even if the cross section is eroded by the ion beam scanned during observation, the slice processing frame 18 can be similarly corrected. As a result, the accuracy at the time of observation can be improved as compared with the conventional analysis method.

Further, in the conventional method of reproducing a cross-sectional image from a plane image, the same area is scanned for processing and observation, so that the processing depth becomes constant. However, in the analysis method of the present embodiment, for example, when there is an area that is not desired to be processed at the bottom (Z direction end) in the slice processing range 16, the area is avoided and other slice lines 17 are provided.
Different depths d can be set in each slice line 17 or different depths d can be set in one slice line 17 within a range that does not hinder observation.

For example, when different depths d are set between the slice lines 17, the processing time of the slice processing frame 18 is set corresponding to the depth d corresponding to the slice processing frame 18 in S16. To be done. On the other hand, when different depths d are set in the one slice line 17, the processing time is changed in S17 according to the position where the ion beam is scanned.

As a result, even if there is an area that is not desired to be processed within the slice processing range 16, it is possible to avoid the area and obtain the cross-sectional image data of the remaining portion. As a result, even if there is a non-destructible portion near the specific portion 11 and the region to be processed has a complicated shape, by specifying the shape in advance, the specific portion can be flexibly compared with the conventional analysis method described above. 11 can be automatically observed.

Further, the focused ion beam apparatus according to this embodiment is provided with a plurality of apertures 35 as shown in Table 1 above. Furthermore, unlike the conventional analysis method described above, processing and observation are performed separately. Therefore, even if the semiconductor element 1 is scanned with ion beams having different ion beam diameters and ion beam current values, no trouble occurs. Therefore, in the analysis method according to the present embodiment, by adding a step of changing the ion beam diameter or the ion beam current value during processing and during observation, the semiconductor element 1 can be scanned with an ion beam suitable for both. As a result, the accuracy at the time of observation can be further improved as compared with the conventional analysis method.

In this embodiment, in S4,
The focus adjustment and conditions for each aperture 35 are stored, and each time the aperture 35 is changed,
Readjustment based on memory. Therefore, when changing the aperture 35, it is not necessary to manually adjust, and the automatic observation of the specific portion 11 becomes easier.

Although the focused ion beam apparatus observes the semiconductor element 1 in this embodiment, the present invention is not limited to this. For example, the analysis method according to this embodiment can be applied to other observation targets such as metals and insulators.

[0092]

As described above, the method for analyzing an object to be observed in the focused ion beam apparatus according to the first aspect of the present invention is such that the cross-section processing step and the observation are performed at a specific position on the object to be observed at a predetermined interval. By repeating the process, the accumulation process of accumulating the position data indicating the position where the cross section is formed in each cross-section processing process and the cross-sectional image data in each observation process, and the cross-sectional image data and the position data accumulated in the accumulation process And a display step of three-dimensionally displaying the shape of the specific portion.

Therefore, as compared with the conventional planar display method, there is an effect that it becomes easier to grasp the defective state of a specific portion and the whole appearance of the defective portion. Furthermore, since it is possible to obtain a cross section at an arbitrary angle from image data of cross sections arranged at a predetermined interval, it is possible to achieve an effect that automatic observation of a specific portion can be realized relatively easily.

In addition, unlike the conventional method of reproducing a cross-sectional image from a plane image, the regions to be irradiated with the ion beam are different from each other in each processing step. As a result, there is an effect that the accuracy at the time of observation can be improved as compared with the conventional analysis method.

As described above, the method for analyzing an object to be observed in the focused ion beam apparatus according to the invention of claim 2 is as follows. The depth can be set separately.

Therefore, as compared with the conventional method of reproducing a cross-sectional image from a plane image, it is possible to automatically observe even a specific portion having a more complicated shape. As a result, it is possible to more easily analyze the relationship between the specific location and the surrounding location.

As described above, the method of analyzing an object to be observed in the focused ion beam apparatus according to the invention of claim 3 is the same as that of the invention of claim 1 or 2, At least one of the ion beam diameter and the ion beam current value is set differently in the observation step and the cross-section processing step.

Therefore, the object to be observed can be scanned with an ion beam suitable for each step, and the accuracy of observation can be further improved as compared with the conventional method of reproducing a sectional image from a planar image.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention and showing a main part of a focused ion beam device equipped with a three-dimensional display device.

FIG. 2 is a view for explaining the function of the focused ion beam device, where (a) is for surface observation and (b) is for
At the time of etching, (c) is a cross-sectional view showing the vicinity of the ion beam irradiation object at each time of the deposition.

FIG. 3 is an explanatory diagram showing a eucentric mechanism provided on a fine movement stage of the focused ion beam apparatus.

FIG. 4 shows an aperture No. 1 in the focused ion beam device. 2 is a graph showing the relationship between the ion beam current value and the ion beam aperture.

FIG. 5 is a flowchart showing a cross-sectional three-dimensional analysis method used in the focused ion beam apparatus.

FIG. 6 is a view for explaining a pretreatment of processing in the focused ion beam apparatus, and is an example of display in alignment of a specific portion.

FIG. 7 is a plan view for explaining a pretreatment for processing in the focused ion beam device, showing an example of marking in the vicinity of a specific portion.

8A and 8B show an example of setting a slice processing frame in the focused ion beam apparatus, FIG. 8A is a plan view showing the vicinity of a specific portion, and FIG. 8B is a slice processing shown in FIG. 8A. It is the enlarged view which expanded the frame vicinity.

FIG. 9 is a cross-sectional view after step processing in the vicinity of a specific portion of a semiconductor element in the focused ion beam device.

FIG. 10 is a plan view showing an example of setting a step processing frame in the focused ion beam apparatus.

FIG. 11 is a plan view showing an example of forming a step processing trace in the focused ion beam device.

FIG. 12 is a plan view illustrating alignment after step processing in the focused ion beam device.

FIG. 13 is a graph showing a relationship between a scanning position and a brightness level when the surface of a semiconductor element including a cross section is scanned in the focused ion beam device.

FIG. 14 is an enlarged plan view for explaining a slicing frame at the time of slicing in the focused ion beam device, showing in detail the vicinity of a specific portion.

FIG. 15 shows the focused ion beam device of FIG.
It is sectional image data obtained by observing the section of each slice line shown in FIG.

16 is a view for explaining a method of converting a sectional image into a three-dimensional image in the focused ion beam apparatus.
It is explanatory drawing which arranged each cross-sectional image data of 5 in three dimensions.

FIG. 17 shows the focused ion beam device of FIG.
3 is a display example in the case where each cross-sectional image data of 3 is displayed three-dimensionally.

FIG. 18 shows a conventional general cross-sectional observation method, in which (a) shows a semiconductor element before observation, (b) shows after rough processing, and (c) shows after finishing processing. It is a perspective view which each shows a specific location, and (d) has shown section image data obtained by observation of a section.

FIG. 19 is a plan view showing an example of a defect that occurs in a semiconductor element, in which (a) is a dust defect portion and (b) is a power leak portion.

FIG. 20 is an explanatory diagram showing another conventional observation method,
(A) is a perspective view showing a specific portion of a semiconductor element before observation, (b) is in the middle of processing, and (c) is a specific view of a semiconductor element after processing.

FIG. 21 is an explanatory diagram showing a method of converting each plane image data into arbitrary sectional image data in the observation method.

[Explanation of symbols]

 1 semiconductor element (observed object) 2 fine movement stage 3 ion beam irradiation unit 4 secondary electron / secondary ion detector 6 control computer 11 specific location 62 storage unit 63 three-dimensional data display processing unit

Claims (3)

[Claims] 1. A cross-section processing step of irradiating a desired position of an object to be observed with an ion beam to perform cross-section processing, and in the cross-section processing step, the cross section formed on the object to be observed is scanned with an ion beam to obtain a target object. In the method of analyzing an observed object of a focused ion beam device, which comprises an observation step of detecting charged particles emitted from an observed object and obtaining cross-sectional image data of the cross-sectional surface, for a specific location of the observed object, An accumulation step of accumulating position data indicating a position where a cross section is formed in each cross-section processing step and cross-sectional image data in each observation step by repeating the cross-section processing step and the observation step at predetermined intervals, and the above-mentioned accumulation step. And a display step of three-dimensionally displaying the shape of the above-mentioned specific location from each cross-sectional image data and position data accumulated in 1. Method. 2. The method for analyzing an observed object of a focused ion beam apparatus according to claim 1, wherein the depth from the surface of the cross section to be formed can be set separately in the cross section processing step. 3. The ion beam diameter and the ion beam current value of the ion beam with which the object to be observed is irradiated are set differently in the observation step and the cross-section processing step. Item 1. A method for analyzing an observed object of the focused ion beam device according to Item 1 or 2.