JP2003022776A - Sample production apparatus and sample production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sample production apparatus and a sample producing method, in which cross-sectional processing at an arbitrary angle is possible, in the ion beam processing in a non-inclining sample stand. SOLUTION: The sample production apparatus is constituted so that a sample section may be formed by ion beam processing in the sample 1 held to the sample stand 2 using an ion beam optical system 5 which converges, scans, and deflects the ion beam 4 emitted from the ion source 9. It is constituted so that the angle, which is made by an ion beam optical axis of the ion beam optical system 5 and the sample stand 2 surface, may be fixed, and formation of the sample section may be controlled by rotation within the sample stand surface of the sample stand 2. With the apparatus arrangement by the non- inclining sample stand effective in reduction of apparatus manufacturing cost, the ion beam irradiation processing at arbitrary angles is attained, and an accurate section can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample manufacturing technique, and more particularly, to irradiating a sample with an ion beam to perform cross-section processing,
The present invention relates to a sample preparation device and method for performing observation.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices such as dynamic random access memories (DRAMs), microprocessors, semiconductor devices such as semiconductor lasers, and electronic parts such as magnetic heads, there is a need to control the quality of products during or after the manufacturing process. Product characteristics are inspected at the end stage. In the inspection, manufacturing dimensions are measured, circuit patterns are inspected for defects, and foreign matters are analyzed. Therefore, various means are prepared and used. In particular, when an abnormal portion exists inside the product, it is necessary to observe a sample cross section at a specific position, and a focused ion beam processing apparatus (FIB apparatus) is widely used for forming this observation cross section.

In this method, a hole is formed by utilizing sputtering by irradiating the sample surface with an ion beam, and a cross section of the hole is observed with a FIB device or a scanning electron microscope (SEM). At this time, the cross section is formed at the end of the ion beam scanning range.

However, the actual formed cross section is not completely perpendicular to the sample surface due to flare of the processing beam and redeposition of the sputtered material (hereinafter referred to as redeposition), and there is a minute inclination (taper). . In the case of an FIB device having a tilting mechanism on the sample stage, the taper is removed by inclining the sample at an angle corresponding to the taper, for example, about 0.5 degrees to irradiate the ion beam, and the observation cross section with a higher verticality is obtained. It was possible to form Regarding this method, for example, "Electron / Ion Beam Handbook 3rd Edition" is used as processing of a cross section of a sample of a transmission electron microscope (TEM).
(Japan Society for the Promotion of Science, 132nd Edition, Nikkan Kogyo Shimbun,
Pp. 459-460).

[0005]

If the FIB device has a tilting mechanism on the sample stage, FIB irradiation can be performed at an arbitrary angle, and the taper removing process can be performed as described above.

However, in recent semiconductor device inspection,
As the diameter of wafers has increased, so has the size of the sample table. There is a problem that it takes time to accurately tilt the large-sized sample stage, and as a result the sample preparation time becomes long. Further, due to the heavy weight of the sample table itself, the sample position with respect to the FIB optical system moves without maintaining eucentricity before and after the tilt, so the FIB focus deviates from the sample surface relatively greatly, and the sample surface is observed. There is also a problem that it becomes impossible to perform readjustment of the FIB optical system.

The tilting function of the sample table is a cause of increasing the size of the sample table itself and the sample chamber containing the sample table. The current trend is that the wafer diameter is 200 mm to 30 mm.
If it is further changed to 0 mm at 400 mm, the size of the sample table is inevitably increased, and it is unavoidable to solve the problems associated with the tilting of the sample table as described above.

On the other hand, if the tilting function can be omitted in the sample stage of the apparatus, the size of the apparatus as a whole can be reduced and problems such as sample position deviation due to sample tilting can be solved. Irradiation was difficult. Japanese Patent Laid-Open No. 3-166744 discloses a method capable of forming a processed hole by obliquely irradiating a sample surface with an ion beam to form an observation cross section.
As disclosed in Japanese Patent Laid-Open Publication "Cross-section observation method", this method describes vertical cross-section processing, but does not describe a method for arbitrarily changing the irradiation angle without tilting the sample table. For this reason, the above taper removal processing is also difficult.

Here, the inclination of the sample stage means that the sample stage is rotated around a line segment included in the surface of the sample stage or a parallel line segment as an axis, and is hereinafter referred to as the inclination of the sample stage.

In view of the above-mentioned problems, the present invention aims to realize a sample manufacturing apparatus and a sample manufacturing method capable of forming a cross section by FIB irradiation at an arbitrary angle within a certain range even on a non-tilted sample stage. To aim.

[0011]

First, terms used in this specification are defined as follows.

The desired cross section is a cross section which the operator of the apparatus intends to form. The set cross section is a cross section on the assumption that the set ion beam scanning region is ideally processed without the influence of the beam diameter or redeposition. The formation cross section is actually FI
It is a cross section formed by B processing. The formation section ridge is an intersection line formed by the formation section and the sample surface. The set cross section ridge is an intersection line between the set cross section and the sample surface. The deflection scanning area edge is one side forming the ion beam scanning area. The desired cross-section ridge is the line of intersection between the desired cross-section and the sample surface. The desired section edge normal direction is a direction from the sample toward the processing space, which is a normal line of the desired section edge within the sample surface. The desired cross-section normal direction is the direction from the inside of the sample to the processing space, which is the normal line of the desired cross-section. The desired depression angle is the angle between the normal direction of the desired cross section and the sample surface.The desired normal direction of the cross section is positive when it goes from the sample surface to the inside of the sample, and when it goes from the inside of the sample to the sample surface (equivalent to the elevation angle. ) Is negative. The set section depression angle is the angle between the normal direction of the set section and the sample surface,
The case where the normal direction of the set cross section goes from the sample surface to the inside of the sample is positive, and the direction from the inside of the sample to the sample surface (corresponding to the elevation angle) is negative.

The following are mentioned as means for achieving the above object. (1) An ion source, a lens for focusing ions emitted from the ion source, an ion beam optical system including a deflector, an ion beam optical system controller for controlling the ion beam optical system, and an ion beam sample Detector for detecting secondary particles from the sample generated when the sample is irradiated with
A sample preparation apparatus that includes a sample stage that holds a sample and a sample position control device that controls the position of the sample stage, and forms a sample cross section on the sample by ion beam processing, wherein the ion beam optical axis of the ion beam optical system and the sample The angle formed by the surface is fixed, and the formation of the sample cross section is controlled according to the set depression angle. This makes it possible to form a cross section having an arbitrary tilt angle even in an apparatus in which the tilt of the sample stage cannot be changed with respect to the ion beam optical system. (2) An ion source, a lens for focusing ions emitted from the ion source, an ion beam optical system including a deflector, an ion beam optical system controller for controlling the ion beam optical system, and an ion beam sample Detector for detecting secondary particles from the sample generated when the sample is irradiated with
In a sample preparation device that includes a sample stage that holds a sample and a sample position control device that controls the position of the sample stage, and a sample preparation device that forms a sample cross section on the sample by ion beam processing, the ion beam optical system control device uses an ion beam optical system. The angle between the optical axis of the ion beam and the sample surface is more than 0 ° and less than 90 °, and the ion beam scanning by the deflector is controlled in accordance with the set sectional depression angle of the set section. Thereby, the FIB irradiation angle at the time of cross-section processing can be arbitrarily set. (3) In the sample preparation device according to the above (1) and (2),
The ion beam optical system controller is configured to control the deflector based on the angle information obtained by projecting the desired depression angle onto the surface whose normal is the ion beam optical axis, corresponding to the setting depression angle of the setting cross section. . Thereby, the ion beam processing setting angle can be controlled, and the FIB irradiation angle at the time of cross-section processing can be arbitrarily set. (4) In the sample preparation device of (1) and (2) above,
The ion beam optical system controller controls the deflector based on the angle information obtained by projecting the set crossing depression angle onto the surface whose normal is the ion beam optical axis, corresponding to the set crossing depression angle of the set cross section. The position control device is configured to control the rotation of the sample table within the surface of the sample table. As a result, it becomes easy to form a cross section with an arbitrary depression angle at an arbitrary processing position by rotating the sample. (5) In the sample preparation device according to any one of (1) to (4) above, angle information obtained by projecting the set crossing depression angle of the set cross section onto a plane whose normal line is the ion beam optical axis is used as a secondary particle by a secondary particle detector. The information is displayed on a display device and set. As a result, the operator can visually perform the processing setting corresponding to the desired FIB irradiation angle. (6) In the sample preparation device of (1) and (2) above,
Depending on the coordinates of the desired cross-section edge, the normal direction of the desired cross-section, and the size parameter, or any one of these equivalent parameters, or a combination of these parameters, the ion beam optical system controller causes the ion beam deflection to be performed. The sample position control device controls the rotation of the sample table within the surface of the sample table. As a result, it becomes possible to automate the machining setting corresponding to the cross-section formation parameter desired by the operator. (7) The sample preparation device according to any one of (1) to (6) above is configured to include an input device for setting a desired cross-section depression angle of a desired cross-section or a parameter equivalent thereto.
This allows the operator to easily set the depression angle of the desired cross section. (8) Irradiate the sample with the ion beam from the tilt direction,
In a sample manufacturing method for manufacturing a cross section by sputtering, a step of setting the depression angle of the cross section at which the sample is desired to be observed and the deflection scanning area of the ion beam are determined by setting the deflection scanning area end corresponding to this depression angle. By preparing the sample from the steps and the step of processing the deflection scanning region with the ion beam, it is possible to form a cross section having an arbitrary inclination angle within a certain range only by controlling the deflection of the ion beam. (9) In the method of preparing a sample according to (8) above, a step of acquiring a rotation angle of a desired cross section, a sample rotation angle corresponding to the depression angle and the rotation angle of the desired cross section are determined, By making a sample from the process of setting the rotation in
It is possible to form a cross section having an arbitrary inclination angle within a range of a desired cross section position. (10) A charged particle beam emitted from a charged particle source is focused, and a charged particle beam optical system for scanning and deflecting is used to form a sample cross section on a sample held on a sample stage by charged particle beam processing. In the sample preparation device described above, the angle between the charged particle beam optical axis of the charged particle beam optical system and the sample table surface is fixed, and the formation of the sample cross section is controlled by rotating the sample table within the sample table surface. A sample preparation device characterized by the above. (11) Sample for forming a sample cross section on a sample placed on a sample stage by charged particle beam processing by using a charged particle beam optical system that focuses, scans and deflects a charged particle beam emitted from a charged particle source In the manufacturing apparatus, the angle between the charged particle beam optical axis of the charged particle beam optical system and the sample surface is fixed, and the normal direction of the set cross section and the sample surface set to form the sample cross section where the sample is desired to be observed. There is provided a sample preparation device characterized by being configured to control scanning and deflection of a charged particle beam optical system in accordance with an angle formed by.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a constitutional block diagram showing an embodiment of a sample preparation apparatus according to the present invention.

The sample preparation apparatus comprises a movable and non-inclined sample table 2 on which a sample 1 such as a semiconductor wafer or a semiconductor chip is placed.
A sample position control device 3 that controls the position of the sample table 2 to identify the observation and processing position of the sample 1, and an ion that irradiates the ion beam 4 near the observation position of the sample 1 to form an observation hole. A beam optical system 5, an electron beam optical system 7 for irradiating an electron beam 6 for observing the vicinity of the sample 1,
It has a secondary particle detector 8 for detecting secondary particles (for example, secondary electrons) from the sample 1.

The structure of the ion beam optical system 5 is as follows. An ion source 9 for generating ions is an acceleration power source 10
Thus, the acceleration voltage is applied to the ground potential. When the ion emission from the ion source 9 is unstable, a power supply 11 for heating electricity is supplied.
To heat the electric current to improve the state of the ion source 9.
An extraction voltage is applied to the ion source 9 by the extraction power supply 13 from the extraction electrode 12 that forms an ion extraction electric field. The ion beam extracted by this is
The aperture 14 limits the beam divergence. The aperture 14 has the same potential as the extraction electrode 12.
The ion beam that has passed through the aperture 14 is focused by a focusing lens 16 to which a focusing voltage is applied by a focusing power supply 15.

The focused ion beam is used by the deflection power source 17
Scanning and deflection are performed by the deflector 18 to which is applied. The deflection power source 17 is a power source 19 or 2 for deflecting in the X direction.
0 and a power supply 21 and 22 for deflecting in the Y direction. The power supplies 19 and 20 have potentials Vx / 2 and -Vx / 2 having the same absolute value but opposite polarities to the counter electrodes in the X direction. Is applied. Similarly, Vy / 2 and -Vy / 2 are set for the power supplies 21 and 22 in the Y direction. The deflected ion beam is focused on the surface of the sample 1 by the objective lens 24 to which the objective voltage is applied by the objective power supply 23.

The acceleration power source 10, the drawing power source 13,
The focusing power supply 15, the deflection power supply 17, and the objective power supply 23 are controlled by the ion beam optical system controller 25. The ion beam optical axis of the ion beam optical system 5 is inclined with respect to the surface of the sample 1.

The electron beam optical system 7 is composed of an electron source 26 for generating electrons, a deflection lens 27 for deflecting and scanning the electron beam, and the like.

The ion beam optical system control device 25, the sample position control device 3, the electron beam optical system control device 28 for controlling the electron beam optical system 7, the display device 29 for displaying the detection information of the secondary electron detector 8, etc. , Central processing unit 30. The sample stage 2, the ion beam optical system 5, the electron beam optical system 7, the secondary electron detector 8 and the like are arranged in the vacuum container 31.

FIG. 2 shows an example of sample processing in an inclined ion beam optical system for observing a cross section. In this configuration, the ion beam optical axis 35 is the vertical axis 40 on the surface of the sample 1.
And the inclination angle 41 is an angle θ larger than 0 ° and smaller than 90 ° here. 37 is an optical axis projection line obtained by projecting the ion beam optical axis 35 on the sample surface. The purpose is to form a processed hole 39 here and observe the formed cross section 38. Here, as shown in FIG. 2, it is assumed that the desired cross-section ridge 37, which is the line of intersection of the formed cross-section 38 and the sample surface, is parallel to the optical axis projection line 36.

At this time, the ion beam processing setting is performed by setting an ion beam scanning region 46 on the secondary electron image 45 in the display device 29, as shown in FIG. In this case, the desired cross-section ridge 37 is parallel to the optical axis projection line 36 (an imaginary line that does not actually exist on the secondary electron image screen).

A sample processing cross section in this case is shown in FIG. In this case, the ion beam 4 is irradiated parallel to the desired cross section 52 to form the processed hole 39. Here, if the ideal processing can be realized, the formed cross section should coincide with the desired cross section 52, but in reality, due to the influence of ion beam flare, redeposition, etc., the formed cross section 51 has the processing taper angle αt. For this reason, there is a possibility that positional deviation will occur with depth and accurate cross-section observation may not be possible, so the following improvements are necessary.

As shown in FIG. 5, when the ion beam 55 is obliquely irradiated at an inclination angle corresponding to the taper angle to form the processed hole 54, the formed cross section 56 is correctly formed at the position of the desired cross section 52. That is, the set cross-section depression angle αd of the set cross-section 58 may be matched with the inclination angle αt corresponding to the taper angle in FIG.

In order to realize this tilt processing with this non-tilted sample stage, the processing settings shown in FIG. 6 are made. In FIG. 6A, the deflection scanning area end 61 (corresponding to the set cross-section edge) of the ion beam scanning area 62 is the processing rotation angle 63 with respect to the optical axis projection line 36.
(Here, the angle is φd).
Here, as shown in FIG. 6B, the entire screen display of the secondary electron image 45 may be rotated by φd, and in this case, the fictitious optical axis projection line 36 is rotated by φd, and The beam scanning area 66 and its deflection scanning area edge 65 (which coincides with the set cross-section edge) appear vertical on the screen of the secondary electron image 45 as in FIG. 3, so that the operator can easily perform the processing setting. Here, φd is calculated by the ion beam optical system controller 25 by the calculation formula shown in (Equation 1), and the deflector 1 is automatically calculated.
Set 8 scans.

[0027]

[Equation 1] Here, since the ion beam optical axis tilt angle θ is determined by the device, the processing setting rotation angle φd is set with respect to the set sectional depression angle αd.
Is uniquely determined. Here, −θ ≦ αd ≦ θ.

FIG. 7 shows the processing at this time,
The set cross-section edge 71 of the processed hole 72 is at an angle of 7 with the optical axis projection line 36.
4 (here, set section edge rotation angle βd) is offset. This βd is represented by (Equation 2).

[0029]

[Equation 2] The relationship between βd and φd is simply expressed as in (Equation 3).

[0030]

[Equation 3] That is, as shown in FIG. 8A, the processing rotation angle φd is 0 °.
In FIG. 3 which is a secondary electron image in the case of, the state where the structural direction 81 to be cross-section processed is parallel to the optical axis projection line 36 is shown.
8 is used as the rotation reference (here, 0 °).
If the sample stage is rotated by βd as shown in (b), the set cross-section ridge 71 coincides with the structural direction 81 in which the cross-section is processed, and the desired observation cross-section can be manufactured.

That is, as described above, since the machining rotation angle φd is determined by the set section depression angle αd, the set section edge rotation angle βd.
The sample stage rotation angle βr determined from is also uniquely determined with respect to the set sectional depression angle αd. Therefore, by performing the calculation of (Equation 2) by the sample position control device 18, it becomes possible to automatically control the rotation of the sample table with respect to the structural direction in which the cross section is processed.

The flow of the above setting is expressed in a block diagram as shown in FIG. First, the user inputs the set sectional depression angle αd (91). This is shown in FIG.
As shown in 0 (a), by inputting to the set sectional depression angle setting unit 101 on the screen of the display device 29, it is transmitted to the ion beam optical system control device 25 via the central processing unit 30.

Next, the user sets the desired section edge (9
3). For example, as shown in FIG.
It is set by designating the starting point (Xs, Ys) 103 and the ending point (Xe, Ye) 104 of the desired section edge 102 on the five screens. The target position is CAD (Computer-Aid) for device design.
ed Design) It is also possible to set the position from the data,
In this case, it is possible to set a lower layer wiring position which is not on the outermost surface of the sample. In this CAD data, in the desired section edge setting 93, the desired section edge 1 is numerically used as coordinate information.
It is also possible to set the start point (Xs, Ys) 103 and the end point (Xe, Ye) 104 of 02. An arrow 105 in FIG. 10 represents a direction of a ridge normal to a desired cross section, and an ion beam processing hole is formed in this arrow direction.

Based on these pieces of information, the ion beam scanning range is first determined. Here, a case where the ion beam scanning itself for capturing the secondary electron image is rotated as described with reference to FIG. 6B will be described. First, the processing rotation angle φd is calculated by (Equation 1) (92). By performing the ion beam scanning rotation for the processing rotation angle φd, the deflection coordinates (Xi, Yj) before the ion beam scanning rotation is expressed by (Expression 4) and (Expression 5) (Xij, Yij). Is converted to.

[0035]

[Equation 4]

[Equation 5] Here, the ion beam scanning area is defined (i = 1 to n,
j = 1 to m) is the desired cross-section edge setting (Xs, Ys), (Xe, Ye)
And the desired section depth Zd (95). This desired section depth Zd setting (94) is input to the desired section depth setting unit 106 on the screen of the display device 29 as shown in FIG. It is transmitted to the system controller 25. (i = 1 to n, j =
1 to m) is determined from the machined hole length determined by the length of the desired section ridge and the machined hole width determined by the section observation angle and the desired section depth Zd. The deflection voltage corresponding to this (Xij, Yij) is calculated by (Equation 6) and (Equation 7) (96).

[0036]

[Equation 6]

[Equation 7] Here, kx and ky are coefficients of deflection in the X and Y directions, respectively, and are determined by the device based on the acceleration voltage 10, the length of the deflector 18, the distance between the counter electrodes, the distance from the deflector 18 to the sample 1, and the like. Is a coefficient. This (Vxij, Vyij) is applied from the deflection power source 17 to control the voltage of the deflector 18. At this time, the set cross-section ridge has the secondary electron image 3 as shown by 65 in FIG. 6B.
It becomes vertical on 6. The desired cross-section ridge 1
The sample stage rotation angle βr required to match 02 with the rotation of the sample stage 2 is determined by the equation (8).
And the rotation of the sample table 2 is controlled.

[0037]

[Equation 8] At this time, on the secondary electron image 45, as shown in FIG. 10B, the ion beam scanning region 108 is (X11, Y11) 109, (X1m, Y1m) 11 with respect to the desired cross-section ridge 107.
0, (Xn1, Yn1) 111, and (Xnm, Ynm) 112 are set as a region surrounded by them. A desired cross section is formed by scanning this region with an ion beam for processing.

If there is a processing error due to the flare of the ion beam and there is a problem, (X11, Y11) 109 and (X1
(m, Y1m) 110 is set by moving the deflection scanning region edge formed by the line segment connecting the (m, Y1m) 110 to the right in FIG. 10B from the desired section 107 by an error amount, and the formed section becomes the desired section 107.

Here, the ion beam optical axis tilt angle θ is 45.
An example of actual processing in the case of ° is shown. (Table 1) shows -45 °
The machining rotation angle φd and the set cross-section ridge rotation angle βd for the set cross-section depression angle αd of + 45 ° are set values obtained from the calculation of (Equation 1) and (Equation 2) (expressed to the first decimal place in degree units). .

(Table 1)

FIG. 14 shows the relationship between the depression angle αd of the formed section and the set depression angle αd of the actually formed section when processed under these conditions.
Shown in. If the processing is ideal, the experimental value 141 is the ideal line 1
It should match 42, but it does not. This deviation is due to the processing taper. Therefore, in order to form an accurate desired cross section, the following flow for automatically correcting the taper angle αt is necessary.

The taper angle αt depends not only on the ion beam energy and the material of the sample, but also on the optical axis tilt angle θ of the ion beam and the desired depression angle αe. Therefore, when the taper angle is expressed as αt (αe, θ), the deflection angle φd of (Equation 1) is controlled by using the set sectional depression angle αd represented by (Equation 9) below, and (Equation 8) It is possible to match the formed cross section with the desired cross section by controlling the rotation of the sample stage βr.

[0043]

[Equation 9] That is, by using a table in which the taper angle αt (αe, θ) αe, θ is used as a parameter, the formed cross section can be automatically prepared at the desired cross section position. When θ is 45 °, this table is as shown in (Table 2).

(Table 2)

As described above, according to the configuration of the present invention, the tilt irradiation angle αd of the ion beam can be arbitrarily selected by automatically controlling the processing setting rotation angle φd and the sample stage rotation angle βr, and the taper removal can be performed. Processing etc. becomes easy.

(Embodiment 2) In this embodiment, an example will be described in which the shape actually processed for making a cross section is a rectangle.

Since the ion beam scanning area described in the first embodiment is rectangular as shown in FIG. 6, the shape actually processed on the sample surface is a parallelogram as shown by 151 in FIG. 15A. Become. Here, reference numerals 153, 154, and 155 are device wirings, and the purpose thereof is to process the positions of the wirings 153 and 154. The formed cross-section ridge 152 is processed so as to intersect the wirings 153 and 154 vertically. In this case, the processing ridge 156 other than the formation cross-section ridge is formed obliquely with respect to the formation cross-section ridge 152, and even the wiring 155, which originally does not need to be processed, may be processed.

Therefore, there is a case where the processing shown in FIG. 15B is desired. That is, it is possible to process only the target wirings 153 and 154 by making the processing shape on the surface of the sample rectangular such as 157 and making the processing edges 159 other than the formation cross-section edges 158 parallel to the wiring 153 and the like. Become.

In order to realize this processing, the processing settings shown in FIG. 16 may be set. This is a diagram corresponding to FIG. 6B, and the entire screen display of the secondary electron image 161 is rotated by φd for display. Here, the deflection scanning area edge 163 is set in the same manner as the deflection scanning area edge 65 of FIG. 6B, but this deflection scanning area 162 is different from the rectangular deflection scanning area 66 of FIG. Set to shape. At this time, the internal angle γ of the parallelogram shown in 164 (displayed in degrees)
Is represented by (Equation 10).

[0050]

[Equation 10] As described above, by processing with the setting of the deflection scanning area 162 of the parallelogram, the rectangular processing of FIG. 15B can be realized, so that the arbitrary inclination processing can be realized without processing a wasteful area. it can.

Example 3 In this example, the sample preparation apparatus according to the present invention was used for TEM observation, energy dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EE).
An example applied to a thin film sample of LS) will be described.

The thin film for TEM observation is required to be thin in order to improve the observation resolution, and is usually processed to have a thickness of about 100 nm. However, as described in Example 1, when the ion beam is irradiated parallel to the observation cross section,
In the TEM thin film processing, tapered thin film cross sections 115 and 116 are formed as shown in FIG. 11, so that the sample has a thickness distribution in the depth direction with respect to the desired observation surface 117.
In this case, an excessive structure is included in the deep region, and the observation accuracy deteriorates. Further, when EDX or EELS is used for compositional element analysis, quantitativeness of the signal amount of X-rays and electron beams is important, but the film thickness is different.
In the case of such samples, it becomes impossible to quantitatively compare the compositions.

To solve this, as described in the first embodiment, the rotation angle φd of the ion beam processing setting is controlled by the ion beam optical system controller 25, and as shown in FIG. By irradiating the beam 121 while inclining it with respect to the desired observation surface 117, the thin film cross section 122
Can be formed parallel to the desired observation surface 117. Similarly, by setting the rotation angle φd in the ion beam processing setting in the opposite direction, the tilted ion beam 1 shown in FIG.
Irradiation of 24 is possible, and a thin film cross section 125 can be formed. This makes it possible to form an observation thin film having high film thickness uniformity.

As described above, according to the configuration of the present invention, the tilt irradiation angle αd of the ion beam can be arbitrarily selected by automatically controlling the processing setting rotation angle φd and the sample stage rotation angle βr. A thin film with high uniformity can be formed, which is effective for improving the observation accuracy of TEM observation and for analysis and quantification of EDX and EELS.

(Embodiment 4) In this embodiment, an example in which the sample preparation apparatus according to the present invention is applied to a sample for depth analysis of Auger electron spectroscopy (AES) or secondary ion mass spectrometry (SIMS) will be described. .

When performing composition analysis in the depth direction of a sample portion having a uniform composition in the direction parallel to the sample surface by AES or SIMS, the depth formed by analyzing the cross section formed at a shallow angle in order to improve the depth direction resolution. The resolution can be improved. FIG. 13A shows an analytical cross-section manufacturing method suitable for such an analysis.

The ion beam 131 is obliquely irradiated by the ion beam deflection control described in the first embodiment, and the processed hole 1 is processed.
33 is formed. By thus forming the formed cross section 132, the internal structure of the sample exposed on the cross section becomes wider than the depth direction of the sample. An electron beam 134 is applied to the forming cross section 132.
Of the sample 1 and the Auger electrons are detected and dispersed to acquire the in-plane composition distribution in the formed cross section 132.
It is possible to obtain the composition distribution in the depth direction. By irradiating an ion beam instead of the electron beam 134, detecting secondary ions and performing mass analysis, it can be used for elemental analysis in the depth direction by SIMS.

By forming a slanted section with a shallow angle by using the sample preparation apparatus in this manner, it is possible to improve the resolution of composition depth analysis such as AES and SIMS.

In the above embodiments, the ion beam processing is taken as an example. However, the present invention is not limited to the ion beam but can be applied to any charged particle beam that can be processed.

[0060]

According to the present invention, since the ion beam irradiation processing can be performed at an arbitrary angle and an accurate cross section can be formed by the apparatus configuration using the non-tilted sample stage which is effective in reducing the apparatus manufacturing cost, the FIB can be formed. The accuracy of SEM observation is improved. In addition, a sample thin film with high film thickness uniformity can be formed,
It is effective for improving the observation accuracy of M observation and for analysis and quantification of EDX and EELS.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a sample preparation device according to the present invention.

FIG. 2 is a diagram showing an example of cross-section processing by ion beam irradiation from an oblique direction.

FIG. 3 is a diagram showing a cross-section processing setting screen on a secondary electron image.

FIG. 4 is a view showing a cross section formed by ion beam parallel irradiation on a desired cross section.

FIG. 5 is a view showing a cross section formed by ion beam tilt irradiation with respect to a desired cross section.

FIG. 6 is a diagram showing a cross-section processing setting screen on a secondary electron image at the time of ion beam tilt irradiation.

FIG. 7 is a diagram showing cross-section processing during ion beam tilt irradiation.

FIG. 8 is a view showing a sample rotation in which a structure for cross-section processing matches a processing setting.

FIG. 9 is a block diagram showing a flow of processing setting according to the present invention.

FIG. 10 shows a processing setting screen

FIG. 11 is a diagram showing thin film processing by ion beam parallel irradiation on a desired cross section.

FIG. 12 is a diagram showing thin film processing by ion beam tilt irradiation on a desired cross section.

FIG. 13 is a diagram showing sample cross-section forming processing suitable for composition analysis in the depth direction.

FIG. 14 is a diagram showing a relationship between a set sectional depression angle and a formed sectional depression angle by an experiment.

FIG. 15 is a diagram showing a difference in device pattern processing depending on a sample surface processing shape.

FIG. 16 is a view showing a deflection scanning area for processing a rectangular hole.

[Explanation of symbols]

1 ... Sample, 2 ... Sample stage, 3 ... Sample position control device, 4 ... Ion beam, 5 ... Ion beam optical system, 6 ... Electron beam, 7 ... Electron beam optical system, 8 ... Secondary electron detector, 9 ...
Ion source, 10 ... Acceleration power supply, 11 ... Electric heating power supply, 12
... Extraction electrode, 13 ... Extraction power supply, 14 ... Aperture, 15 ... Focusing power supply, 16 ... Focusing lens, 17 ... Deflection power supply, 18 ... Deflector, 23 ... Objective power supply, 24 ... Objective lens, 25 ... Ion beam optical system control Device, 26 ... Electron source, 27 ... Deflection lens, 28 ... Electron beam optical system control device, 29 ... Display device, 30 ... Central processing unit, 31 ... Vacuum container, 35 ... Ion beam optical axis, 36 ... Optical axis projection line Three
7 ... Desired cross section ridge, 38 ... Formed cross section, 39 ... Machining hole, 40
... vertical axis of sample surface, 41 ... tilt angle, 45 ... secondary electron image, 46 ... ion beam scanning region, 51 ... forming cross section, 5
2 ... Desired cross section, 55 ... Ion beam, 56 ... Formation cross section,
57 ... Machining hole, 58 ... Setting section, 61 ... Setting section edge, 6
2 ... Ion beam scanning area, 63 ... Machining rotation angle, 65 ...
Set section ridge, 66 ... Ion beam scanning area, 71 ... Set section ridge, 72 ... Machining hole, 73 ... Forming section, 74 ... Set section ridge rotation angle, 81 ... Structural direction for section processing, 101 ... Set section depression angle setting section , 102 ... Desired cross-section edge, 105 ... Arrow, 106 ... Desired cross-section depth setting portion, 107 ... Desired cross-section edge, 108 ... Ion beam scanning region, 115, 116 ...
Thin film cross section 117 ... Desired observation plane 121 ... Ion beam 122, 123 ... Thin film cross section, 124 ... Ion beam, 125 ... Thin film cross section, 131 ... Ion beam, 132
... forming cross section 133 ... processing hole, 134 ... electron beam, 1
41 ... Experimental value, 142 ... Ideal line, 151 ... Machining shape, 1
52 ... Formation cross-section ridge, 153, 154, 155 ... Wiring, 1
56 ... Machining edge, 157 ... Machining shape, 158 ... Forming cross-sectional edge, 159 ... Machining edge, 161 ... Secondary electron image, 162 ... Deflection scanning area, 163 ... Deflection scanning area edge, 164 ... Interior angle.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toru Ishitani             882 Ichimo, Hitachinaka City, Ibaraki Stock Association             Company Hitachi Ltd. measuring instrument group (72) Inventor Hiroyasu Shichi             1-280, Higashikoigakubo, Kokubunji, Tokyo             Central Research Laboratory, Hitachi, Ltd. (72) Inventor Hideo Kashima             1-280, Higashikoigakubo, Kokubunji, Tokyo             Central Research Laboratory, Hitachi, Ltd. (72) Inventor Muneyuki Fukuda             1-280, Higashikoigakubo, Kokubunji, Tokyo             Central Research Laboratory, Hitachi, Ltd. F term (reference) 2G052 AA13 AB00 AC28 AD32 AD52                       BA02 EC18 FD11 GA33 HC04                       HC06 JA01 JA09                 5C034 AA02 AB03 AB04 BB04 BB06                       BB07

Claims (9)

[Claims] 1. A sample cross section is formed on a sample held on a sample stage by charged particle beam processing by using a charged particle beam optical system that focuses, scans and deflects a charged particle beam emitted from a charged particle source. In the sample preparation apparatus configured as described above, the angle formed between the charged particle beam optical axis of the charged particle beam optical system and the sample table surface is fixed, and the sample table is rotated within the sample table surface, whereby the sample cross section A sample preparation apparatus characterized in that formation is controlled. 2. A sample cross section is formed on a sample mounted on a sample stage by charged particle beam processing by using a charged particle beam optical system that focuses, scans and deflects a charged particle beam emitted from a charged particle source. In the sample preparation apparatus, the angle between the charged particle beam optical axis of the charged particle beam optical system and the sample surface is fixed, and a method of a set cross section set to form a sample cross section desired to observe the sample A sample preparation device characterized by being configured to control scanning and deflection of the charged particle beam optical system according to an angle formed by a line direction and the surface of the sample. 3. An ion beam optical system comprising an ion source, a lens for focusing ions emitted from the ion source, and a deflector, and an ion beam optical system controller for controlling the ion beam optical system. A detector for detecting secondary particles from the sample generated when the sample is irradiated with an ion beam, a sample stage for holding the sample, and a sample position control device for controlling the position of the sample stage. In a sample preparation device for forming a sample cross section on the sample by ion beam processing, the angle formed by the ion beam optical axis of the ion beam optical system and the sample surface is fixed, and the sample is observed. It is configured to control the formation of the sample cross section in accordance with the normal direction of the set cross section set to form a desired sample cross section and the set cross section depression angle formed by the sample surface. Sample Preparation and wherein the door. 4. An ion beam optical system having an ion source, a lens for focusing ions emitted from the ion source, and a deflector; an ion beam optical system controller for controlling the ion beam optical system; A detector for detecting secondary particles from the sample generated when the sample is irradiated with an ion beam, a sample stage for holding the sample, and a sample position control device for controlling the position of the sample stage. In a sample preparation apparatus for forming a sample cross section on the sample by ion beam processing, the ion beam optical system control device includes an ion beam optical axis of the ion beam optical system and a sample surface at an angle greater than 0 ° and greater than 90 °. Corresponding to the normal angle direction of the set cross section set to form a sample cross section that is less than ° and desired to observe the sample and the set cross section depression angle formed by the sample surface. And a sample preparation device configured to control the ion beam scanning by the deflector. 5. The ion beam optical system controller controls the deflector based on angle information obtained by projecting the set sectional depression angle on a surface having the optical axis of the ion beam as a normal line. The sample preparation device according to claim 3 or 4. 6. The ion beam optical system control device controls the deflector based on angle information obtained by projecting the set sectional depression angle on a surface having the optical axis of the ion beam as a normal line, and controls the sample position. The sample preparation device according to claim 3 or 4, wherein the device controls rotation of the sample table within a surface of the sample table. 7. The angle information obtained by projecting the set depression angle on a plane whose normal is the ion beam optical axis is displayed on a display device for displaying secondary particle information by the secondary particle detector. The sample preparation device according to claim 3 or 4, characterized in that. 8. A sample preparation method for irradiating a sample with an ion beam from an inclination direction through an ion beam optical system to form a sample cross section on the sample by a sputtering process. A step of setting a depression angle, a step of forming a deflection scanning region of the ion beam on the sample corresponding to the depression angle, a step of setting the deflection scanning region, and an ion beam processing of the deflection scanning region. A method for preparing a sample, comprising: 9. A step of obtaining a rotation angle of a desired sample cross section of the sample with respect to an optical axis projection line obtained by projecting an ion beam optical axis of the ion beam optical system onto the sample surface, the depression angle and the desired angle. 9. The sample manufacturing method according to claim 8, further comprising the step of determining a sample rotation angle corresponding to the rotation angle of the cross section and setting the rotation of the sample table in the sample table plane.