JP2000208090A - Converged ion beam machining device and etching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a converged ion beam machining device capable of forming an etched slot having a desired size at a desired position of a sample in a manner that sets its side walls at a desired angle. SOLUTION: This device is provided with an ion source 2 for emitting an ion beam IB, and a sample stage 8 equipped with a rotary stage that holds a semiconductor element 12 and rotates the semiconductor element 12; and adjusts an angle at which the ion beam IB enters into the surface of the semiconductor element 12 by adjusting the inclination angle of an ion column 1 having the ion source 2 on its inside. Then, etching is performed by irradiating with the ion beam IB the semiconductor element 12 rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focused ion beam apparatus and an etching method which are used, for example, when correcting a wiring of a semiconductor element having a plurality of wirings formed in multiple layers.

[0002]

2. Description of the Related Art A processing apparatus using a focused ion beam includes:
In every field, it is widely used when fine processing is required. For example, a focused ion beam processing apparatus is used for correcting wiring of an LSI, observing a local cross section, and preparing a sample during observation with a transmission electron microscope.

FIG. 22 is a schematic diagram showing a schematic configuration of a conventional focused ion beam processing apparatus. This focused ion beam processing apparatus includes an ion source 52, an electrostatic lens 53, and a deflection lens 54 disposed inside an ion column 51.
And a detector 56, a deposition nozzle 57, a sample stage 58, and a dedicated nozzle 59 disposed inside the processing chamber 55.
And a plurality of gas cylinders 6 arranged outside the processing chamber 55.
0 ... and a gas pipe 61.

[0004] The ion source 52 is mainly composed of liquid metal as a raw material. This liquid metal is generally Ga
⁺ (Gallium) ions are used. An ion beam IB extracted from the ion source 52 has a diameter of at least 0.1 mm by an electrostatic lens 53 disposed below the ion source 52.
The light is focused down to 01 μm, and reaches the surface of the semiconductor element 62 to be processed, which is fixed on the sample stage 58.

When the ion beam IB is scanned by operating the deflecting lens 54, the semiconductor device 6
Secondary ions and secondary electrons are emitted from the surface of No. 2.
These secondary ions and secondary electrons are supplied to the detector 5
6, after being subjected to image processing, the image is displayed on a display (not shown) as an image of the processed portion.

As described above, physical sputtering occurs by irradiating the ion beam IB to a specific region of the semiconductor element 62, whereby a fine hole can be formed on the semiconductor element 62.

Further, a metal film can be formed at an arbitrary position of the semiconductor element 62 by performing the following processing using the above focused ion beam processing apparatus. First, the metal compound gas is supplied to the deposition nozzle 57.
From the surface of the semiconductor element 62 to adsorb gas components. When the ion beam IB is irradiated onto the adsorbed metal compound gas, the compound gas is separated by a chemical reaction, and the ion beam IB
A metal film is deposited at the position where is irradiated.

As a result, it is possible to form a metal film at an arbitrary position on the semiconductor element 62, and it is possible to form fine wiring on the semiconductor element 62. Also,
By changing the compound gas to have an insulating property, an insulating film can be formed at an arbitrary position on the semiconductor element 62 by the same principle.

In the above-described processing for forming a fine hole on the semiconductor element 62, by performing the following processing, the processed shape of the hole can be improved. First, a reactive gas is introduced into the processing chamber 55 through a pipe 61 from gas cylinders 60 provided outside the processing chamber 55 in which the sample stage 58 is disposed. Inject.

Then, as described above, when forming a fine hole by irradiating a specific region on the semiconductor element 62 with the ion beam IB, a reactive gas is injected from the dedicated nozzle 59 onto the surface of the semiconductor element 62. I do. by this,
The spatter ejected from the ion beam IB irradiation location can be prevented from re-adhering to the ion beam IB irradiation location. That is, by reducing the re-adhesion of the sputtered material, it becomes possible to perform high-speed etching with a clean processed shape compared to the case where no reactive gas is used.

The reactive gas is roughly divided into:
XeF ₂ (mixed with fluorine) and Cl ₂ (mixed with chlorine) are used. Both are reactive gases having a selectivity, and Xe
In the case of using F _2, when the etching speed with respect to oxide film, about 3 to 4 times faster than the etching speed for Si and Al, with Cl ₂ is, Al
And the etching speed of Si is about 10 times faster than the etching speed of the oxide film. Therefore,
When ion beam processing is performed using a reactive gas, it is necessary to select and use a gas suitable for the material of the film to be processed.

As described above, the reactive gas used when performing the etching process by the focused ion beam is generally called an assist gas because it has an effect of supporting the etching process.

Next, the processing shape when the conventional focused ion beam processing method is used will be described.

FIG. 23A is a cross-sectional view showing the shape of an etching groove 63 when the semiconductor element 62 is etched by irradiating the semiconductor element 62 without using an assist gas. The etching is performed under the conditions that the current value of the ion beam IB is 100 pA, the diameter of the opening region is 1 μm, and the etching depth is 3 μm. Looking at the cross-sectional shape, the surface 64 of the semiconductor element 62 and the etching groove 6
It can be seen that sagging has occurred in the upper side wall 65 corresponding to the entrance portion of No. 3 and it has a rounded shape.

As shown in FIG. 24, the beam intensity distribution of the ion beam IB has a distribution like a Gaussian distribution curve 66. The upper side wall 65 located at the entrance of the etching groove 63 also has this Gaussian distribution curve. A small amount of the ion beam IB corresponding to the 66 seo portion will be irradiated. Therefore, the upper portion 65 of the side wall located at the entrance of the etching groove 63 is necessarily rounded.

FIG. 23 (a) shows the normal direction 67 to the surface 64 of the semiconductor element 62 and the etching groove 63 when the processing is performed under the processing conditions of not using the assist gas as described above. Side wall inclination direction 68
FIG. 4 is an explanatory diagram showing a relationship with the above. As shown in this figure, the angle between the normal direction 67 and the side wall inclination direction 68 is 1
1.2 °.

FIG. 23B is a cross-sectional view showing the shape of the etching groove 63 when the semiconductor element 62 is etched by irradiating the semiconductor element 62 with an ion beam IB using an assist gas. The etching is performed under the conditions that the current value of the ion beam IB is 100 pA, the diameter of the opening region is 1 μm, and the etching depth is 3 μm. Since the semiconductor element 62 in which the film to be etched is an oxide film is used, XeF ₂ (fluorine mixed) is used as the assist gas.
Gas is used. The gas pressure at this time is adjusted so that the degree of vacuum in the processing chamber 55 is stabilized at around 4 × 10 ⁻⁶ torr.

When the assist gas (XeF ₂ ) is used, the reattachment of the sputtered material from the irradiation position of the ion beam IB to the irradiation position is reduced, so that the side wall of the etching groove 63 is compared with the case where the assist gas is not used. The verticality has been improved. However, as described above, since the Gaussian distribution type of the ion beam IB exists even when the assist gas is used, the upper side wall 65 located at the entrance of the etching groove 63 also has a rounded shape. That is,
Etching groove 6 even when assist gas is used
3 cannot be eliminated, and the etching groove 6 cannot be removed.
3 has a tapered shape.

FIG. 23B shows the normal direction 67 to the surface 64 of the semiconductor element 62 and the etching groove 63 when the processing is performed under the processing conditions of using the assist gas as described above. It is explanatory drawing which shows the relationship with the inclination direction 68 of the side wall. As shown in this figure, the angle formed between the normal direction 67 and the side wall inclination direction 68 is 2.0
°. That is, the angle between the normal direction 67 and the side wall inclination direction 68 is smaller by 9.2 degrees than in the case where the assist gas is not used, and the verticality is improved.

The above processing method has a problem that a deep etching groove 63 cannot be formed particularly in a minute area. Hereinafter, this problem will be described.

FIG. 25 is a sectional view showing a shape when a deep etching groove 63 is formed in the semiconductor element 62 by the processing method as described above. As shown in FIG. 25, in the case of the etching groove 63 in which the verticality of the side wall is impaired, as the etching depth 63D increases, the opening region 63A becomes narrower, and the areas of the opening bottom surface 63B and the opening region 63A are clearly different. It will be.

FIG. 26 is a graph showing the relationship when the etching depth 63D is plotted on the horizontal axis and the size of the opening area 63A is plotted on the vertical axis. In FIG. 26, G1
Shows a graph when no assist gas is used, and G2
Shows a graph when an assist gas is used.
The processing conditions are such that the diameter of the opening region 63A when the etching depth 63D is 0 is 1.0 μm (1.0 μm).
mφ), the current value of the ion beam IB is 100 pA, and the etching depth 63D is 5 μm.

As shown in FIG. 26, the graph G1 when the assist gas is not used and G2 when the assist gas is used are both lower right in the graph. This indicates that the size of the opening region 63A decreases as the etching depth 63D increases. Each time the etching depth 63D increases by 1 μm, the size of the opening region 63A decreases by 21% when the assist gas is not used, and by 14% when the assist gas is used.

FIG. 27 is a cross-sectional view showing a cross-sectional structure of a semiconductor element 69 in which a plurality of wiring layers M1 to M5 are formed. In such a semiconductor element 69, in order to perform a process such as a correction on a specific wiring L1 of the lowest wiring hierarchy M1, it is necessary to form a hole reaching the wiring L1. . In this case, the etching groove 70 reaching the wiring L1 by the processing method as described above.
FIG. 28 shows a cross-sectional structure of the semiconductor element 69 in which is formed.

As shown in FIG. 28, it can be seen that the opening region is significantly changed between the upper and lower portions of the etching groove 70. Wiring L1 located at the lowest wiring hierarchy M1
In order to etch down to
A needs to be set large in advance. However, by increasing the size of the opening region 70A, the wirings L2 and L3 adjacent to the etching groove 70 come into contact with the etching groove 70. As described above, depending on the wiring structure of the semiconductor element, a case in which an etching groove having a desired depth cannot be formed frequently occurs.

Next, as described above, the etching process in the case where the wiring is formed in a plurality of layers inside the sample to be processed will be described in more detail with reference to FIGS. Will be considered. In the following description, a sample 71 to be processed is formed therein with wirings 72 arranged in a plurality of layers and processing target wirings 73 to be subjected to processing such as correction. It is assumed that For simplicity, the ion beam IB is affected by the Gaussian distribution characteristic described above.
It is assumed that the tip has a wedge shape.

FIG. 29 is a cross-sectional view showing a shape when the etching groove 75 on the surface of the sample 71 is processed so as to be equal to the processing width 74 required for the wiring 73 to be processed. As shown in FIG. 29, the ion beam IB
Due to the wedge shape, the etching grooves 75
Has a shape that is inclined inward as it proceeds inside the sample 71. Accordingly, as described above, when the ion beam IB is moved and processed so that the width of the etching groove 75 on the surface of the sample 71 becomes the processing width 74 required for the wiring 73 to be processed, The etching groove 75 that reaches the wiring 73 to be processed cannot be formed.

FIG. 30 is a cross-sectional view showing a shape when the etching groove 75 reaches the wiring 73 to be processed and the width of the bottom of the etching groove 75 becomes the processing width 74. As shown in FIG. 30, in this case, the width of the etching groove 75 on the surface of the sample 71 is larger than the processing width 74 due to the inclination of the side wall of the etching groove 75. Therefore, there is a possibility that the processing may affect the other wiring 72 adjacent to the etching groove 75.

FIG. 31 shows that, after the sample 71 is arranged at an angle, the etching groove 75 reaches the wiring 73 to be processed.
FIG. 13 is a cross-sectional view showing a shape when processing is performed so that a width of a bottom portion of an etching groove 75 becomes a processing width 74. As shown in FIG. 31, by inclining the sample 71, the left side wall 75L of the etching groove 75 is formed perpendicular to the surface of the sample 71. However, the right side wall 75R of the etching groove 75 has an inclination angle further away from the vertical direction with respect to the surface of the sample 71. Therefore, the other wiring 7 near the side wall 75R
2 is more likely to affect the processing.

Therefore, the sample 71 is arranged at an angle, and the center of the region to be processed is set as an axis.
Assume a configuration in which processing is performed while rotating 1. In this case, first, as shown in FIG. 32, the sample 71 is processed so that the width of the etching groove 75 on the surface of the sample 71 is equal to the processing width 74 in a state where the sample 71 is inclined. Then, the left side wall of the etching groove 75 is formed perpendicular to the surface of the sample 71. On the other hand, the right side wall of the etching groove 75 is located at the right end of the processing width 74 on the surface of the sample 71, but is located on the inner side of the right end of the processing width 74 on the surface of the wiring 73 to be processed. are doing.

Then, from the state shown in FIG.
Is processed while rotating about the center of the processing width 74 as an axis, a state shown in FIG. 33 is obtained. That is, the side walls on both sides of the etching groove 75 are perpendicular to the surface of the sample 71, and the width of the etching groove 75 is formed to be equal to the processing width 74 from the surface of the sample 71 to the wiring 73 to be processed. .

As a configuration capable of realizing the processing method as shown in FIGS.
There is a configuration disclosed in Japanese Unexamined Patent Application Publication No. H11-163,873. The configuration disclosed in Japanese Utility Model Application Laid-Open No. 5-84014 is a configuration as a scanning electron microscope, but the configuration for holding a sample is applicable to a focused ion beam processing apparatus.

FIG. 34 is a sectional view showing a schematic configuration of the sample device of the scanning microscope. This sample device includes a sample rotation stage 76, a sample holder 80, an X-direction moving stage 8
1, a Y-direction moving stage 82, a tilt stage 83, and a Z-direction moving stage 84 are provided. When the sample rotation stage 76 is rotated by a specific driving source, the gear 77 set on the sample rotation stage 76 rotates. The rotation of the gear 77 causes the gear 78 connected to the gear 77 to rotate about the rotation axis R. The rotation of the gear 78 causes the actual sample 79
Is mounted, the sample holder 80 rotates. As a result, the sample 79 set in the sample holder 80 is rotated.

In this sample apparatus, the tilt angle between the sample rotating stage 83 and the sample holder 80 on which the sample is mounted is fixed. In order to position the sample 79 at the center of the observation field when the sample rotation stage 83 is rotated, it is necessary to constantly arrange the sample 79 on the rotation axis R.

Next, the problem that the upper portion 65 of the side wall corresponding to the entrance portion of the etching groove 63 is sagged, which has been described with reference to FIGS. The conventional method will be described. As such a conventional method, Japanese Patent Application Laid-Open No. 64-42822 discloses a method for processing a semiconductor substrate.

In this conventional method, as shown in FIG. 35A, in order to prevent sagging at the upper part of the side wall of the etching groove due to the Gaussian distribution of the ion beam intensity, the upper surface of the semiconductor substrate 86 is Upper layer 8 on the entire surface
5 (SiO ₂ or SiN ₂ film). Then, as shown in FIG. 35B, the reactive gas SiF ₄
While supplying the gas 88 from the radical supply pipe 87 onto the semiconductor grave plate 86, the ion beam IB is applied to an arbitrary opening area to form an etching groove as shown in FIG.

The SiO ₂ or SiN ₂ film used as the upper film 85 has a small reactivity with the ion beam, it is possible to prevent sagging in the upper portion of the side wall of the etched groove.

[0038]

However, a configuration in which the sample is arranged obliquely and processed while rotating the sample about the center of the region to be processed as an axis has a structure as shown in FIG. When using the device,
The following problems arise.

As shown in FIG. 34, the sample rotating stage 7
6 and the sample holder 80 on which the sample 79 is mounted have a fixed inclination angle. Therefore, sample 7
Beam IB due to factors such as material change
When the inclination angle of the side wall of the etching groove formed by the above changes, it is impossible to adjust the inclination angle to an appropriate one. That is, such an apparatus cannot form an etching groove having an optimal shape.

The configuration shown in FIG. 34 is provided with a tilt stage 83, and according to the above publication, the sample 79
Is described, the tilt stage 83 is tilted by a drive source (not shown).
However, according to the description and the drawings, the tilt stage 83 can be tilted only in the direction in which the tilt direction of the sample 79 is increased. That is, it is impossible to control the tilt angle of the sample to an arbitrary angle.

When the etching process is performed while rotating the sample, it is necessary to move the portion to be processed to the center of rotation. In this case, in the case of the configuration shown in FIG. 34, there is no means for relatively moving the positional relationship between the sample 79 and the sample holder 80 as a rotating body, and the positional relationship between the sample 79 and the rotation axis R is moved. It is not possible. Therefore, for example, when there are a plurality of processing locations in one sample, the sample 79 is removed from the sample holder 80 each time the processing in one processing location is completed, and the sample 79 is again placed in the next processing location. Needs to be re-attached to the sample holder 80 so that is placed on the rotation axis R.

In this case, it is required that the positioning accuracy when mounting the sample 79 to the sample holder 80 is extremely high. However, in the case of the above-mentioned configuration, since the mounting is performed manually by a human, the necessary positioning accuracy is required. The positioning accuracy cannot be obtained. Therefore, it is extremely difficult to form an etching groove of a desired size at a desired location.

In the method of processing a semiconductor substrate described in Japanese Patent Application Laid-Open No. Sho 64-42822, etching is performed after an upper layer 85 made of a material having low reactivity is formed on a semiconductor substrate 86. By doing so, dripping at the upper part of the side wall of the etching groove is prevented. However, since it is not considered that the beam intensity of the ion beam IB has a Gaussian distribution and the sidewall of the etching groove is formed to be inclined, the sidewall of the etching groove is made to face the surface of the semiconductor substrate 86. It is impossible to make it vertical.

The present invention has been made in order to solve the above-mentioned problems. An object of the present invention is to provide an etching groove of a desired size at a desired position with respect to a sample, and a side wall of the etching groove having a desired angle. It is an object of the present invention to provide a focused ion beam processing apparatus and an etching method which can be formed as follows.

[0045]

According to a first aspect of the present invention, there is provided a focused ion beam processing apparatus for performing an etching process by irradiating a sample with an ion beam. Is characterized by comprising an ion source for emitting an ion beam, sample holding means for holding a sample, and incident angle control means for adjusting an angle at which the ion beam is incident on the sample to an arbitrary angle.

According to the above arrangement, the angle of incidence of the ion beam on the sample can be adjusted to an arbitrary angle by the incident angle control means, so that the beam intensity and beam diameter of the ion beam are changed. Also in this case, by adjusting the incident angle of the ion beam, the angle of the side wall of the formed etching groove can be formed to a desired angle, for example, vertical.

A focused ion beam processing apparatus according to a second aspect is characterized in that, in the configuration according to the first aspect, the sample holding means includes a rotating stage for rotating the sample at an arbitrary cycle.

According to the above configuration, the sample can be rotated at an arbitrary cycle by the rotation stage provided in the sample holding means, so that the etching process can be performed by irradiating the ion beam while rotating the sample. . That is, after adjusting the angle at which the ion beam is incident on the sample by the incident angle control means, the etching process can be performed while rotating the sample, so that the angles of all the side walls of the etching groove are at the desired angle and It can be formed to be constant.

According to a third aspect of the present invention, in the focused ion beam processing apparatus according to the first or second aspect, the incident angle control means adjusts an inclination angle of an ion column having the ion source therein. It is a control means.

According to the above arrangement, by adjusting the inclination angle of the ion column having the ion source therein,
Since the angle at which the ion beam is incident on the sample is adjusted, the incident angle of the ion beam can be changed without shifting the irradiation position of the ion beam on the sample.

According to a fourth aspect of the present invention, there is provided a focused ion beam processing apparatus for performing an etching process by irradiating a sample held by a sample holding means with an ion beam. An XY-direction moving stage that can change an inclination angle, a rotation stage that can rotate about a rotation axis, and an XY-direction moving stage that can change an arrangement position in a plane; It is arranged on a stage, and the sample is held on the XY direction moving stage.

According to the above configuration, the sample can be moved to an arbitrary position in the horizontal plane and in the vertical direction by the XYZ direction moving stage. The normal direction of a specific surface of the sample can be set to an arbitrary direction by adjusting the tilt angle of the tilt stage. In addition, the sample is
It can be rotated about a rotation axis. Further, the positional relationship between the rotation axis and the sample can be changed by the XY stage arranged on the rotation stage.
Therefore, it is possible to position the center of the target processing portion on the sample at the intersection of the rotation axis and the central axis of the ion beam scanning area. By locating the sample in this manner, it is possible to perform the etching process by rotating the sample while keeping the angle of incidence of the ion beam on the sample at a desired angle. It can be formed at a desired angle and constant.

Further, even when there are a plurality of target processing portions in the sample, the respective stages provided in the sample holding means are appropriately moved so that each target processing portion is arranged at a desired position and in a desired direction. Becomes possible.

According to a fifth aspect of the present invention, there is provided an etching method comprising the steps of: rotating a sample at a predetermined cycle around a target processing portion on a sample; Irradiating the ion beam from a direction inclined by a predetermined angle from, including forming an etching groove to a desired depth, the predetermined angle at the time of irradiating the ion beam, the beam intensity of the ion beam and And / or setting based on the beam diameter.

According to the above-described method, the sample is rotated at a predetermined cycle around the target processing location on the sample, and the target processing location is inclined by a predetermined angle from the normal direction of the surface of the sample. Since the etching groove is formed to a desired depth by irradiating the ion beam from the set direction, the etching can be performed so that the angles of all the side walls of the etching groove become a desired angle and become constant.

Further, since the predetermined angle for irradiating the ion beam is set based on the beam intensity and / or the beam diameter of the ion beam, when the beam intensity and / or the beam diameter of the ion beam is changed, Also, the angles of all the side walls of the etching groove can be set to desired angles.

According to a sixth aspect of the present invention, in the method of the fifth aspect, the cycle of rotating the sample is set in a range of 0.05 to 0.1 nc / rotation. I have.

According to the above method, the disorder of the etching groove due to the rotation error caused when the sample is rotated faster,
When the rotation of the sample is slowed, it is possible to prevent unevenness of the shape of the etching groove due to a long irradiation time of the ion beam. Therefore, a well-shaped etching groove can be formed.

According to a seventh aspect of the present invention, in the method of the fifth or sixth aspect, an etching groove is formed after forming a metal or insulating film on the upper surface of the target processing portion. It is characterized by.

According to the above-described method, since an etching groove is formed after a metal or insulating film is formed on the upper surface of a target processing portion, a portion of a Gaussian distribution curve showing a beam intensity distribution of an ion beam is formed. The sag at the upper part of the etching groove caused by the above is formed only in the above-mentioned film portion. Therefore, it is possible to prevent etching damage from occurring on the surface of the sample.

[0061]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic diagram showing a schematic configuration of a focused ion beam processing apparatus according to the present embodiment. This focused ion beam processing apparatus includes an ion source 2, an electrostatic lens 3, and a deflecting lens 4 disposed inside an ion column 1.
, A detector 6, a deposition nozzle 7, a sample stage (sample holding means) 8, and a dedicated nozzle 9 disposed inside the processing chamber 5, and a plurality of gas cylinders 10 and gas pipes disposed outside the processing chamber 5. 11 is provided. In addition, the ion column 1 is configured such that its mounting angle can be changed with respect to the processing chamber 5, and its movable range is such that the ion column 1 stands upright with respect to the processing chamber 5. From ± 45 ° in the left-right direction. The tilt angle of the ion column 1 is controlled by a tilt angle control unit (not shown). FIG. 2 shows a state in which the ion column 1 is arranged in a state inclined with respect to the processing chamber 5.

The ion source 2 is mainly composed of liquid metal as a raw material. Generally, Ga ⁺
(Gallium) ions are used.
Emits an ion beam IB.

The electrostatic lens 3 is disposed below the ion source 2, and controls the diameter of the ion beam IB by passing the ion beam IB emitted from the ion source 2 through the center thereof. The deflecting lens 4 is disposed further below the electrostatic lens 3, and controls the traveling direction of the ion beam IB by passing the ion beam IB emitted from the ion source 2 through the center thereof.

On the sample stage 8, a semiconductor element 12 to be processed is fixedly mounted, and the ion beam IB emitted from the ion source 2 passes through the electrostatic lens 3 and the deflecting lens 4. The semiconductor device 12 is irradiated.

The detector 6 detects secondary ions and secondary electrons generated when the semiconductor device 12 is irradiated with the ion beam IB. The deposition nozzle 7 is a nozzle for spraying a metal compound gas to an irradiation position of the ion beam IB, and is used when a metal film is formed on the semiconductor element 12.

The dedicated nozzle 9 is a nozzle for spraying a reactive gas introduced from the gas cylinders 10 through the gas pipe 11 to the irradiation position of the ion beam IB.

The operation of forming an etching groove on the semiconductor element 12 in the focused ion beam processing apparatus having the above configuration will be described below.

First, the semiconductor element 12 is placed in a fixed state on the sample stage 8, and the inside of the processing chamber 5 is evacuated until the degree of vacuum reaches 2 × 10 ^-7 torr. Then, the ion beam IB extracted from the ion source 2 is
The electrostatic lens 3 converges to a minimum diameter of 0.01 μm and irradiates the surface of the semiconductor element 12 on the sample stage 8.

At this time, secondary ions and secondary electrons are emitted from the portion of the surface of the semiconductor element 12 irradiated with the ion beam IB. After these secondary ions and secondary electrons are detected by the detector 6 and subjected to image processing, 100 to 10 are displayed on a display (not shown) as an image of a processed portion on the surface of the semiconductor element 12.
It is enlarged and projected in the range of 10,000 times.

FIGS. 3 to 6 are side views showing the structure and operation of the sample stage 8. FIG. The sample stage 8 has a stage structure in which three stages are vertically stacked on a base 16 as shown in FIG. 3, for example. Specifically, a lower stage (rotary stage) 15, a middle stage 14, and an upper stage 13 are arranged on a base 16 in this order from below. Then, the semiconductor element 12 to be processed is fixedly arranged on the upper stage 13.

The lower stage 15 is configured to be able to rotate 360 ° relative to the base 16 at an arbitrary cycle. In addition, the middle stage 14 disposed thereon
It is configured to be movable in the Y direction. Further, the upper stage 13 disposed thereon is configured to be movable in a direction perpendicular to the moving direction of the middle stage 14, that is, in the X direction. In the above description, two directions perpendicular to each other in the horizontal plane are referred to as X directions, respectively.
In FIGS. 3 to 6, the left-right direction of the drawing is the X direction, and the direction perpendicular to the drawing is the Y direction.

Further, the lower stage 15 is configured so that the direction of its surface can be inclined within a range of ± 45 ° with respect to the base 45. That is, the ion column 1
Can be adjusted in the range of ± 45 °, the angle at which the ion beam IB irradiates the surface of the semiconductor element 12 can be adjusted in the range of ± 90 °.

Next, the operation of the sample stage 8 will be described. First, as shown in FIG. 3, the semiconductor element 12 is mounted on the upper stage 13 in a fixed state. Next, FIG.
As shown in the figure, the upper stage 13 and the middle stage 1
4 is moved to a position on the center axis A of the lower stage 15,
Adjust so that is positioned.

Next, as shown in FIG.
B is applied to the processing location 17 on the semiconductor element 12 and the lower stage 15 is rotated while observing the surface. At this time, if the processing location 17 is adjusted so as to be located on the central axis A, even if the lower stage 15 is rotated, the processing location 17 will only rotate on the central axis A and will not shift. . If the processing location 17 is displaced during rotation of the lower stage 15, the upper stage 13 and the middle stage 14 are placed in a state where the surface of the semiconductor element 12 is observed.
Is fine-adjusted to find a point where the processing location 17 does not shift at all.

Next, as shown in FIG.
Is adjusted so that the ion beam IB is irradiated at an inclined angle with respect to the surface of the semiconductor element 12. The inclination angle set here is set so that the side wall of the etching groove formed at the processing location 17 is vertical. The relationship between the inclination angle and the shape of the etching groove will be described later in detail.

Then, while the lower stage 15 is rotated at a constant speed, the ion beam IB is applied to the processing location 17 for processing. At this time, as described above, if the processing location 17 and the rotation axis A are adjusted so as to coincide with each other,
Even if the lower stage 15 is rotated at a constant speed, the processing location 17 does not shift.

Then, the ion beam IB is applied to the processing portion 17.
In this state, the processing (etching) is performed while injecting an assist gas having a selectivity from the dedicated nozzle 9 onto the surface of the semiconductor element 12.

At this time, the rotation speed of the lower stage 15 is
Most preferably, it is set to 0.1 nc / 1 rotation. nc
The unit indicates the amount of ions implanted per unit area, and is used as an expression of the etching speed. 1μ
To etch a depth of m requires about 4 nc,
The etching time required at this time changes depending on the ion beam current value used. 400p ion beam current
In the case of A, it takes 60 seconds to etch a depth of 1 μm, and when the ion beam current value is 100 pA,
Four times 240 seconds are required. When the ion beam current value is changed as described above, the etching time is changed, but the ion implantation amount per unit area is the same.

Regarding the processing shape, the ion beam current value is 10 times higher than when the ion beam current value is 400 pA.
At 0 pA, the beam is finely processed because the beam diameter is smaller. In addition, when the rotation speed of the lower stage 15 is increased (for example, 0.05 nc / 1 rotation), there is basically no major problem, but there is a concern that a rotation error may occur during the rotation of the stage. Conversely, when the rotation speed of the lower stage 15 is reduced (for example, 0.3 nc / 1 rotation), the irradiation time of the ion beam to one location becomes longer, so that the processing shape becomes more uneven. Therefore, the optimum rotation speed of the lower stage 15 is about 0.1 nc / 1 rotation, and the lower stage 15 can be rotated at a speed increased to 0.05 nc / 1 rotation.

Next, the relationship between the inclination angle of the ion column 1, that is, the angle (incident angle) between the direction of incidence of the ion beam IB on the semiconductor element 12 and the normal line of the semiconductor element 12, and the shape of the etching groove Will be described below with reference to FIG.

FIG. 7 is a table showing the shape of the etching groove according to the incident angle in the case of two types of ion beam current values. The incident angle is set in the range of 0 ° to 10 °. When the ion beam current value is 400 pA, the opening area of the etching groove is set to 2 μmφ, and when the ion beam current value is 100 pA, the opening area of the etching groove is 0.1 μm. It is set to be 5 μmφ. The depth of the etching groove is set to 5 μm in both cases.

When the incident angle is 0 °, the aperture area is 2 μm
In the case of φ and the case where the opening area is 0.5 μmφ, both sides have an inclined shape such that the side wall of the etching groove becomes narrower toward the bottom of the etching groove. Also, when the incident angle is 8 °, compared to the case where the incident angle is 0 °,
Regarding the inclination of the side wall of the etching groove, the verticality is improved in both the case where the opening area is 2 μmφ and the case where the opening area is 0.5 μmφ, but a slight inclination is still observed. When the incident angle is set to 10 °, the aperture area is 2 μmφ.
In both cases (1) and (2), the side wall of the etching groove is inclined in the opposite direction, that is, inclined so as to become wider toward the bottom of the etching groove. That is, the inclination angle of the ion column 1 is too large. When the incident angle is 9.8 °, the aperture area is 2
In both the case of .mu.m.phi. and the case where the opening area is 0.5 .mu.m.phi., a vertical etching groove is obtained, which indicates that the incident angle is most suitable.

The reason why the ion beam current value is set to 400 pA when the opening area is formed to have a diameter of 2 μmφ is to shorten the processing time. When the opening area is 0.5 μmφ, the ion beam current value is set to 100 p.
The reason for setting to A is to improve the shape of the etching groove by narrowing the beam diameter to 0.1 μmφ because the aperture region is a minute region.

Next, a procedure for forming an etching groove will be described below with reference to FIGS.

First, the inclination angle of the ion column 1 was set to 9.8.
° and the processed portion 17 of the semiconductor element 12 is irradiated with the ion beam IB at an incident angle of 9.8 °. At this time,
By adjusting the processing location 17 to be located at the center of the rotation axis A of the lower stage 15, the lower stage 15
With the rotation of, the positional deviation of the processing location 17 is prevented from occurring.

Next, as shown in FIG. 8, while the assist gas is jetted from the dedicated nozzle 9 to the surface of the semiconductor element 12, the rotation of the lower stage 15 is stopped, and 1 μm
An ion beam I having a current value of 100 pA
B is irradiated while scanning as shown by the arrow in FIG. 8 to form an etching groove. As described above, the shape of the ion beam IB reflects the Gaussian distribution of the intensity, but in FIG.
For simplicity, the shape of the ion beam IB is described as a wedge.

At this time, in FIG.
The left side wall 18L of the etching groove is formed by the left end portion IBL of the beam region when B is located at the leftmost position, and the right side portion of the etching groove is formed by the right end portion IBR of the beam region when the ion beam IB is positioned at the rightmost position. A wall 18R is formed. Further, the incident angle of the ion beam IB is set to 9.8 °.
, The left end IB of the ion beam IB
L is perpendicular to the surface of the semiconductor element 12. Therefore, the left side wall 1 which is one side wall of the etching groove
8L is formed to be perpendicular to the surface of the semiconductor element 12.

FIG. 9 shows the shape of the etching groove when the etching groove is formed without rotating the lower stage 15 in this manner.

Next, the inclination angle of the ion column 1 is set to 9.8.
The lower stage 15 is rotated at 0.05 to 0.1 nc / rotation while maintaining the ion beam IB having the current value of 100 pA in the opening area of 1 μmφ in the same manner as in FIG.
Irradiation is performed while scanning as indicated by the arrow. By rotating the lower stage 15, as shown in FIG. 10, the ion beam IB is applied to the side wall portion P to which the ion beam IB has not been applied. Finally, as shown in FIG. 11, an etching groove is formed in which all side walls of the etching groove are perpendicular to the surface of the semiconductor element 12.

According to the above-described method, the open area 1 μm
It is possible to form an etching groove of mφ and a depth of 10 μm such that all side walls thereof are perpendicular to the surface of the semiconductor element 12.

Next, a case is described in which the semiconductor element 12 having a structure in which various wirings are formed in multiple layers is subjected to processing such as correction for wirings located in a deep layer.
This will be described below.

FIG. 12 is a cross-sectional view showing a cross section of the semiconductor element 12 on which the wiring layers M1 to M5 are formed. First, the contents to be corrected in the circuit design are examined, and when the target wiring 19 to be corrected is determined, the minimum value D between the wirings of the corrected part is calculated from the layout data of the semiconductor element 12. As an example, the minimum value D between the wires of the upper layer is 0.2 μm.
m. When the minimum value D is obtained, the aperture area is set so as to fall within this range, and the ion beam current value is selected. Then, etching is performed by using the method described above until the depth reaches the target wiring 19, and the etching groove 18 is formed.
To form When the minimum value D between the wirings is 0.2 μm, the ion beam current value may be set to 100 pA.

FIG. 13 shows an enlarged view of the vicinity of the upper portion of the etching groove 15. According to the above-described etching method, it is possible to form the side wall of the etching groove 15 so as to be perpendicular to the surface of the semiconductor element 12. Occurs. This is because, as described above, the surface of the semiconductor element 12 is irradiated with the sine portion of the Gaussian distribution curve in the intensity distribution of the ion beam IB.

In order to prevent dripping at the upper portion of the etching groove 15, as shown in FIG.
A metal or insulating film 20 is formed in advance at the position where the is formed. When an opening area is set from above the formed film 20 and etching is performed, the surface of the film 20 is rounded off due to the influence of the swelling portion of the Gaussian distribution curve, but the surface of the semiconductor element 12 is not cut off. .

FIG. 15 shows an enlarged view of the vicinity of the upper portion of the etching groove 15 in this case. As shown in FIG.
The sag occurring in the opening region occurs in the film 20 formed in advance, and no etching damage is observed on the surface of the semiconductor element 12. That is, by forming the metal or insulating film 20 in advance at the position where the etching groove 15 is to be formed, the protective film is formed on the opening region, and the surface of the semiconductor element 12 is not damaged. In addition, it becomes possible to form an etching groove excellent in verticality.

[Embodiment 2] Another embodiment of the present invention will be described below with reference to FIGS. The components having the same functions as those described in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, another configuration of the sample stage 8 in the first embodiment will be described. FIG. 16 is a schematic diagram illustrating a schematic configuration of the sample stage 8 in the present embodiment.

As shown in FIG. 16, the sample stage 8 in the present embodiment includes an XY-direction moving stage 21, a rotating stage 22, a tilting stage 23, an XYZ-direction moving stage 24, and a stage rotating mechanism box 28. XY direction moving stage 21, rotating stage 22,
Tilt stage 23 and XYZ direction moving stage 24
Are stacked and arranged in this order from the top, and the stage rotation mechanism box 28 is arranged inside these components. Then, the semiconductor element 12 as a sample
Is mounted on the XY direction moving stage 21 in a fixed state.

The XY-direction moving stage 21 is configured to be slidable in two directions (X and Y directions) orthogonal to each other in a horizontal plane, and is driven by an XY-direction moving stage driving device 25. Rotary stage 22
Is rotatable about a rotation axis A on the tilt stage 23, and is rotated by a stage rotation mechanism box 28. The stage rotating mechanism box 28 is driven by a rotating stage driving device 29.

The tilt stage 23 is tilted via a stage tilt mechanism box 23A so that the normal direction of the surface is tilted from the vertical direction, and is driven by a tilt stage driving device 26. The XYZ direction moving stages 24 are two orthogonal to each other in a horizontal plane.
It is configured to be movable in the directions (X and Y directions) and the vertical direction (Z direction), and is driven by an XYZ direction moving stage driving device 27.

In the above configuration, when the rotary stage 22 rotates, the XY-direction moving stage 21 and the semiconductor element 12 mounted thereon rotate simultaneously. At this time, the position of the XY-direction moving stage 21 is controlled so that the target processing location (for example, the target processing location P1) on the semiconductor element 12 is always located on the rotation axis A.

Further, the XYZ direction moving stage 24 moves the target processing portion (for example, the target processing position P) on the semiconductor element 12.
The arrangement position is controlled such that the center of 1) is the center of the scanning area by the ion beam IB, and the distance between the ion source 2 (not shown) and the target processing location is kept constant. Then, the XYZ-direction moving stage driving device 27, the tilt stage turbulence device 26, the rotating stage driving device 29, and the XY-direction moving stage driving device 25 described above.
Are integrally controlled by a control device (not shown).

FIG. 17 shows a stage rotation mechanism box 28.
FIG. 18 is a schematic diagram illustrating a schematic configuration of a stage tilt mechanism box 23A and an arrangement in the vicinity thereof.
FIG. 7 is a side view when viewed from the left in FIG.

As shown in FIG. 17, the stage rotating mechanism box 28 includes a rotating shaft gear 32, a rotating drive shaft gear 33,
A rotation drive shaft 34, a rotation drive motor 35, and a rotation stage shaft 36 are provided. FIG.
As shown in FIG. 7 and FIG. 18, the stage tilt mechanism box 23A includes a tilt stage driving shaft 30 and a tilt driving motor 31.

A stage tilt mechanism box 23A and a tilt stage 23 are mounted on the XYZ direction moving stage 24. The tilt stage 23 and the stage tilt mechanism box 23A are connected via a tilt stage driving shaft 30. I have. Further, a motor 31 for driving the tilt is connected to the shaft 30 for driving the tilt stage, and the driving of the motor 31 for driving the tilt is controlled by the device 26 for driving the tilt stage.
Is adjusted.

The tilt stage 23 and the rotary stage 22
It is connected via a stage rotation mechanism box 28. When the rotation stage 22 rotates, the rotation driving motor 35 in the stage rotation mechanism box 28 mounted inside the tilt stage 23 and the rotation stage 22
Is driven. That is, the rotation drive motor 35 is driven by the rotation stage drive device 29, and the rotation of the rotation drive motor 35 is controlled by the rotation drive shaft 3.
4. The rotation stage 22 is rotated by transmitting the rotation drive gear 33, the rotation shaft gear 32, and the rotation stage shaft 36 in this order, and finally transmitting the rotation stage 22 to the rotation stage 22.

Next, the sample stage 8 having the above-described configuration is used.
Will be described with reference to FIGS. 19 to 21.

FIG. 19 shows a state where the tilt stage 23 is in a horizontal state and the target processing position P1 is within the visual field of processing. Here, the processing visual field indicates the scanning area of the ion beam. FIG. 20 shows the tilt stage 2
3 shows a state in which the target processing point P1 is in the processing visual field. In other words, the state shown in FIG. 20 shows a state in which the stage has been moved from the state shown in FIG. 19 to a state in which the daily processing location P1 is actually etched.

The state change of each stage is as follows. The tilt stage 23 is an XYZ direction moving stage 2
4 is tilted by a predetermined tilt angle via a stage tilting mechanism box 23A. The deviation of the XYZ coordinates of the target processing portion P1 caused at this time is caused by the XYZ direction movement stage 2
4 is corrected. Such position correction control is performed by a control device (not shown).

As described above, the processing target point P1 is the rotation axis A
And at the coordinates of the intersection with the central axis B of the ion beam scanning area. Further, the position between the ion source 2 (not shown) and the target processing portion P1 is controlled by the position correction control of the XYZ direction moving stage 24 so that the distance is always kept constant.

Then, after correcting the position of the target processing portion P1 due to the inclination of the inclination stage 23, the stage rotating mechanism box 2 is rotated by the rotating stage driving device 29.
The rotary stage 22 is rotated through 8 to perform an etching process. The rotation speed of the rotary stage 22 can be arbitrarily adjusted by the rotary stage driving device 29.

As described above, the movement of each stage until the etching process is actually started is controlled by the above-described control device or the like.

FIG. 21 shows a state where the target processing location has moved from the target processing location P1 to the target processing location P2. The state change of each stage when the state shown in FIG. 20 changes to the state shown in FIG. 21 is as follows.

First, after the processing in the state shown in FIG. 20 is completed, once the tilt stage 23 is controlled so that the tilt automatically becomes 0 degrees. Then, from this state, X
The XY-direction moving stage 21 is moved by the Y-direction moving stage driving device 25 to move the target processing location to the target processing location P2. At this time, in the same manner as when changing from the state shown in FIG. 19 to the state shown in FIG.
The XY-direction moving stage 21 is moved by the control device so that the target processing portion P2 is located on the rotation axis A and on the center axis B of the scanning region of the ion beam.

In the above description, the direction of the positional coordinate shift between the target processing point P1 and the target processing point P2 is as follows.
The positional relationship is not limited to one of the X direction and the Y direction, and the positional relationship may be shifted in both the X direction and the Y direction. That is, when processing an actual semiconductor element, it is assumed that the coordinates of the target processing location exist at random. Even in such a case, if the sample stage 8 in the present embodiment is used, the processing visual field is moved to the target processing location. In this case, control can be performed such that the processing target portion is always located on the rotation axis A of the rotary stage 22 and on the center axis B of the ion beam scanning area.

[0117]

As described above, the focused ion beam processing apparatus according to the first aspect of the present invention emits an ion beam in a focused ion beam processing apparatus that performs etching by irradiating a sample with an ion beam. An ion source, a sample holding means for holding a sample, and an incident angle control means for adjusting an angle at which an ion beam is incident on the sample to an arbitrary angle.

Accordingly, even when the beam intensity and the beam diameter of the ion beam are changed, the angle of the side wall of the etching groove to be formed is adjusted to a desired angle by adjusting the incident angle of the ion beam. This has the effect that it can be performed.

A focused ion beam processing apparatus according to a second aspect of the present invention is configured such that the sample holding means includes a rotary stage for rotating the sample at an arbitrary cycle.

Thus, in addition to the effect of the configuration of claim 1, the angle of incidence of the ion beam on the sample can be adjusted by the incident angle control means, and the etching process can be performed while rotating the sample. There is an effect that the angle of all the side walls of the etching groove can be formed to be a desired angle and constant.

A focused ion beam processing apparatus according to a third aspect of the present invention is configured such that the incident angle control means is an inclination angle control means for adjusting an inclination angle of an ion column having the ion source therein.

Thus, in addition to the effects of the first and second aspects, there is an effect that the incident angle of the ion beam can be changed without shifting the irradiation position of the ion beam on the sample.

A focused ion beam processing apparatus according to a fourth aspect of the present invention is the focused ion beam processing apparatus for performing an etching process by irradiating a sample held by a sample holding means with an ion beam. Has a tilt stage that can change the tilt angle, a rotary stage that can rotate around a rotation axis, and an XY-direction moving stage that can change an arrangement position in a plane, wherein the XY-direction moving stage includes: The sample is arranged on the rotary stage, and the sample is held on the XY-direction moving stage.

As a result, the center of the target processing portion on the sample can be located at the intersection of the rotation axis and the central axis of the ion beam scanning area. By locating the sample in this manner, it is possible to perform the etching process by rotating the sample while keeping the angle of incidence of the ion beam on the sample at a desired angle. This has the effect of being able to be formed at a desired angle and to be constant.

Even when there are a plurality of target processing locations on the sample, the respective stages provided in the sample holding means are appropriately moved so that each target processing location is arranged at a desired position and in a desired direction. This has the effect that it becomes possible.

An etching method according to a fifth aspect of the present invention includes a step of rotating the sample at a predetermined cycle around a target processing location on the sample, and a method of forming a surface of the sample relative to the target processing location. Irradiating the ion beam from a direction inclined by a predetermined angle from the line direction to form an etching groove to a desired depth, the ion beam irradiation at a predetermined angle, the ion beam beam The setting is made based on the intensity and / or the beam diameter.

Thus, the sample is rotated at a predetermined cycle around the target processing portion on the sample, and the ions are ionized from a direction inclined at a predetermined angle from the normal direction of the surface of the sample with respect to the target processing portion. Since the etching groove is formed to a desired depth by irradiating the beam, there is an effect that the etching can be performed so that the angles of all the side walls of the etching groove are a desired angle and constant.

Further, the beam intensity of the ion beam and / or
Alternatively, even when the beam diameter is changed, there is an effect that the angles of all the side walls of the etching groove can be set to a desired angle.

In the etching method according to the sixth aspect of the present invention, the cycle when rotating the sample is set to 0.05 to
Set to the range of 0.1 nc / rotation.

Thus, in addition to the effect of the method according to claim 5, in addition to the disorder of the etching groove due to a rotation error caused when the rotation of the sample is accelerated, or the irradiation time of the ion beam when the rotation of the sample is delayed, Since the unevenness of the shape of the etching groove due to the lengthening can be prevented, it is possible to form an etching groove having a uniform shape.

In the etching method according to the present invention, an etching groove is formed after forming a metal or insulating film on the upper surface of the target processing portion.

Thus, in addition to the effect of the method according to claim 5 or 6, in addition to the effect of the method according to claim 5 or 6, the sagging of the upper part of the etching groove caused by the swelling portion of the Gaussian distribution curve showing the beam intensity distribution of the ion beam, Only will be formed. Therefore, there is an effect that etching damage can be prevented from being generated on the surface of the sample.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a focused ion beam processing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration when the ion column is inclined in the focused ion beam processing apparatus.

FIG. 3 is a schematic view showing one operation mode of a sample stage provided in the focused ion beam processing apparatus.

FIG. 4 is a schematic view showing another operation mode of the sample stage.

FIG. 5 is a schematic diagram showing still another operation mode of the sample stage.

FIG. 6 is a schematic diagram showing still another operation mode of the sample stage.

FIG. 7 shows two types of ion beam current values.
5 is a table showing shapes of etching grooves according to incident angles.

FIG. 8 is an explanatory diagram showing an operation during an etching process.

FIG. 9 is a cross-sectional view showing a shape of an etching groove when the etching groove is formed without rotating the lower stage in the sample stage.

FIG. 10 is a cross-sectional view showing a region where etching is not performed when an etching groove is formed without rotating the lower stage.

FIG. 11 is a cross-sectional view showing the shape of the etching groove when the etching groove is formed with the lower stage rotated.

FIG. 12 is a cross-sectional view showing a state where an etching groove is formed in a semiconductor element on which a plurality of wiring layers are formed.

FIG. 13 is an enlarged cross-sectional view showing the vicinity of an upper portion of the etching groove shown in FIG. 12 in an enlarged manner.

FIG. 14 is a cross-sectional view showing a state in which an insulating film is formed in advance on the semiconductor element shown in FIG. 12 at a position where an etching groove is to be formed, and then the etching groove is formed.

FIG. 15 is an enlarged cross-sectional view showing the vicinity of an upper portion of the etching groove shown in FIG. 14 in an enlarged manner.

FIG. 16 is a schematic diagram showing a schematic configuration of a sample stage provided in a focused ion beam processing apparatus according to another embodiment of the present invention.

FIG. 17 is a schematic diagram showing a schematic configuration of a stage rotating mechanism box and a stage tilting mechanism box provided in the sample stage and an arrangement in the vicinity thereof.

FIG. 18 is a side view when viewed from the left in FIG.

FIG. 19 is a schematic view showing one operation mode of the sample stage.

FIG. 20 is a schematic view showing another operation mode of the sample stage.

FIG. 21 is a schematic view showing still another operation mode of the sample stage.

FIG. 22 is a schematic diagram showing a schematic configuration of a conventional focused ion beam processing apparatus.

FIGS. 23A and 23B are cross-sectional views showing the shape of an etching groove formed by a conventional focused ion beam processing apparatus. FIG. 23A shows a case where an assist gas is not used. FIG. 2B shows a case where an assist gas is used.

FIG. 24 is a graph showing an intensity distribution of an ion beam.

FIG. 25 is a cross-sectional view showing a shape when a deep etching groove is formed in a semiconductor element.

FIG. 26 is a graph showing the relationship when the etching depth is plotted on the horizontal axis and the size of the hole area is plotted on the vertical axis.

FIG. 27 is a cross-sectional view showing a configuration of a semiconductor device in which a plurality of wiring layers are formed.

28 is a cross-sectional view showing a state when an etching groove is formed in the semiconductor element shown in FIG. 27.

FIG. 29: The width of the etching groove on the surface of the sample is
It is sectional drawing which shows the shape at the time of processing so that it may become equal to the required processing width with respect to the wiring to be processed.

FIG. 30: An etching groove reaches a wiring to be processed, and
It is sectional drawing which shows the shape at the time of processing so that the width | variety of the bottom part of an etching groove might become a processing width.

FIG. 31 is a cross-sectional view showing a shape when the etching groove reaches the wiring to be processed and the width of the bottom of the etching groove is equal to the processing width after the sample is arranged at an inclination; .

FIG. 32 is an explanatory view showing a state in which the sample is processed so that the width of the etching groove on the surface of the sample is equal to the processing width in a state where the sample is inclined.

FIG. 33 is an explanatory diagram showing a state where the sample is processed while being rotated about the center of the processing width as an axis from the state shown in FIG. 32;

FIG. 34 is a cross-sectional view showing a schematic configuration of a sample device of a conventional scanning microscope.

FIGS. 35A to 35C are explanatory views showing a conventional method for processing a semiconductor substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ion column 2 Ion source 8 Sample stage (sample holding means) 12 Semiconductor element (sample) 13 Upper stage 14 Middle stage 15 Lower stage 16 Base 17 Target processing place 18 Etching groove 19 Target wiring 20 Film 21 XY direction movement stage 22 Rotation Stage 23 Tilt stage 23A Stage tilt mechanism box 24 XYZ direction moving stage 28 Stage rotation mechanism box A Rotation axis B Center axis P1, P2 Target machining point

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Sodegaki 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 5C001 AA03 AA05 AA06 BB07 CC07 5C034 BB07 BB08 CC01 CC08 CC19 CD08 DD06 5F004 BA17 BB24 CA05 EA19 EA38

Claims (7)

[Claims] A focused ion beam processing apparatus for performing an etching process by irradiating a sample with an ion beam, an ion source for emitting an ion beam, a sample holding means for holding the sample, and an ion beam applied to the sample. A focused ion beam processing apparatus comprising: an incident angle control unit that adjusts an incident angle to an arbitrary angle. 2. The focused ion beam processing apparatus according to claim 1, wherein said sample holding means includes a rotating stage for rotating the sample at an arbitrary cycle. 3. The focused ion beam machining according to claim 1, wherein said incident angle control means is an inclination angle control means for adjusting an inclination angle of an ion column having said ion source therein. apparatus. 4. A focused ion beam processing apparatus for performing an etching process by irradiating a sample held by a sample holding means with an ion beam, wherein the sample holding means comprises: a tilt stage capable of changing a tilt angle; A rotation stage rotatable about a rotation axis; and an XY-direction moving stage capable of changing an arrangement position in a plane. The XY-direction moving stage is disposed on the rotation stage. A focused ion beam processing apparatus wherein a sample is held on an XY-direction moving stage. 5. A step of rotating the sample at a predetermined cycle around a target processing portion on the sample, and a direction inclined at a predetermined angle from a normal direction of a surface of the sample with respect to the target processing portion. Forming an etching groove up to a desired depth by irradiating the ion beam from a predetermined angle. The predetermined angle at the time of irradiating the ion beam is set based on the beam intensity and / or beam diameter of the ion beam. Etching method. 6. The method according to claim 1, wherein the rotation cycle of the sample is set to 0.
6. The etching method according to claim 5, wherein the etching rate is set in a range of 0.5 to 0.1 nc / rotation. 7. An etching method according to claim 5, wherein an etching groove is formed after forming a metal or insulating film on the upper surface of the target processing portion.