JPH11183339A - Sample preparation method for transmission electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily prepare a sample for a transmission electron microscope at a specific position. SOLUTION: A sample 1 is sliced by dicing saw machining. An electron beam is radiated near a specific observation position of the sample 1, and a reaction product 3 is deposited. The sample 1 is covered with a plasma polymerization film 4. A focused ion beam is scanned on the sample 1, and the specific observation position is spatter-etched to the thickness of 0.1 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a sample of a transmission electron microscope for observing a specific portion.

[0002]

2. Description of the Related Art Generally, a transmission electron microscope (T
A great deal of labor and time has been required to prepare a sample of (EM). Therefore, in recent years, a focused ion beam apparatus (F
A method for manufacturing a cross-sectional sample using IB) has attracted attention and is becoming a general method in the field of semiconductor devices. FIG. 7 shows steps of a TEM observation method using a conventional FIB. In FIG. 7A, reference numeral 1 denotes a sample, and 2 denotes an observation specific portion.

As shown in FIG. 7B, a sample is sliced by mechanical polishing or a dicing saw. Next, FIG.
As shown in (c), the Ga ion beam is scanned over the sample by the FIB, and the thickness of the observation portion is reduced to 0.1 μm.
Rectangular processing is performed on both sides of the observation point. Next, as shown in FIG. 7 (d), the finished surface is made horizontal, the electron beam is transmitted, and observation with a transmission electron microscope is performed.

[0004]

However, for example, with the miniaturization and high integration of semiconductor devices, it has become difficult to accurately slice a specific portion. Furthermore, in FIB, secondary electron image observation is possible because the setting of the processing area and the change in the shape of the sample are continuously observed.
Since the sample is scanned with ions having a large atomic radius, the resolution of the obtained secondary electron image is not so high, and it is difficult to observe a small area of 0.1 μm or less.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a method for preparing a sample of a transmission electron microscope at a specific portion of a minute area.

[0006]

In order to achieve this object, a method for preparing a sample of a transmission electron microscope according to the first aspect of the present invention is to slice a sample having a specific portion observed by a transmission electron microscope by dicing saw processing. A step of irradiating the sample with an electron beam in the vicinity of the observation specific portion to deposit a reaction product, a step of coating the sample with a plasma polymerized film, and a process of scanning the sample with a focused ion beam to make the observation specific portion thick. 0.1
sputter etching to a thickness of μm.

The method for preparing a sample of a transmission electron microscope according to the second aspect of the present invention includes a step of laser marking a sample having a specific portion observed by the transmission electron microscope, a step of thinning the sample by dicing saw processing, A step of irradiating an electron beam in the vicinity of the observation specific area to deposit a reaction product, a step of coating the sample with a plasma polymerized film, and a step of scanning the sample with a focused ion beam so that the observation specific area has a thickness of 0.1 μm.
sputter etching to a thickness of m.

According to a third aspect of the present invention, there is provided a method for preparing a sample of a transmission electron microscope, comprising the steps of: dicing a sample having a specific portion observed by the transmission electron microscope by dicing saw processing; and forming a conductive film on the sample. A step of irradiating the sample with an electron beam in the vicinity of a specific observation position to deposit a reaction product, a step of coating the sample with a plasma-polymerized film, and a step of scanning the sample with a focused ion beam to reduce the thickness of the specific observation position to zero. . Sputter etching to a thickness of 1 μm.

According to a fourth aspect of the invention, there is provided a method for preparing a sample of a transmission electron microscope, comprising the steps of: laser marking a sample having a specific portion observed by a transmission electron microscope; thinning the sample by dicing saw processing; Forming a conductive film on the sample, irradiating the sample with an electron beam in the vicinity of a specific observation area, depositing a reaction product, coating the sample with a plasma polymerized film, and scanning the sample with a focused ion beam. And sputter-etching the observation specific portion to a thickness of 0.1 μm.

In a fifth aspect of the present invention, there is provided a method for preparing a sample of a transmission electron microscope, comprising the steps of: forming a conductive film on a sample having a specific portion observed by the transmission electron microscope; and thinning the sample by dicing saw processing. A step of irradiating the sample with an electron beam in the vicinity of a specific observation position to deposit a reaction product, a step of coating the sample with a plasma-polymerized film, and scanning the sample with a focused ion beam so that the specific observation position has a thickness of 0%. . Sputter etching to a thickness of 1 μm.

According to a sixth aspect of the present invention, there is provided a method for preparing a sample for a transmission electron microscope, comprising the steps of: forming a conductive film on a sample having a specific portion observed by the transmission electron microscope; laser marking the sample; A process of thinning by dicing saw processing, a process of irradiating an electron beam to the vicinity of a specific point of observation of the sample to deposit a reaction product, a process of coating the sample with a plasma polymerized film, and scanning the sample with a focused ion beam And sputter-etching the observation specific portion to a thickness of 0.1 μm.

With these configurations, the method for preparing a sample for a transmission electron microscope of the present invention can simplify the preparation of a sample for a transmission electron microscope at a specific portion of a minute area. This is realized by enlarging the shape of the reaction product formed by the electron beam by coating the plasma polymerized film and easily identifying it by FIB.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for preparing a sample for a transmission electron microscope according to a first embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 (a) to 1 (e) are a plan view and a sectional view of a process of a method for preparing a sample of a transmission electron microscope according to the present invention. In the figure, 1 is a sample, and 2 is an observation specific portion.
Using a dicing saw, the sample 1 shown in FIG.
As shown in FIG. 1B, 2.0 mm × 0.3 mm × 0.
Process into a 6 mm strip.

Next, in the scanning microscope (SEM), for example, an electron beam having an acceleration voltage of 20 kV, a beam current of 10 pA, and a beam diameter of 0.1 μm is irradiated to the vicinity of the observation specific portion 2 of the sample 1 for 30 seconds. As shown in c), the reaction product 3 is deposited as a marking. At this time, a columnar carbon film having a diameter of about 0.1 μm is formed.

Next, as shown in FIG. 1D, methane gas and ethylene gas are used in a plasma polymerization film forming apparatus.
The plasma polymerization film 4 is coated. The conditions for forming the plasma polymerized film at this time were a gas pressure of 10.7 Pa, a gas mixture ratio of 3: 8 (methane: ethylene), a DC voltage of 1.8 kV, and a discharge current of 6 mA. The above gas forms an amorphous carbon film as a plasma polymerized film. By coating the plasma polymerized film 4, the shape of the reaction product 3 is enlarged as compared with the time of deposition. For example, when the plasma polymerized film 4 is covered with 1.0 μm, it is expanded into a 0.5 μm diameter sphere. By increasing the level difference and marking shape,
The marking part can be easily identified by the FIB.

Next, in the FIB, for example, an acceleration voltage of 30 k
V, G of the ion beam current in the range of 10 nA to 15 pA
a Scanning over the sample using a focused ion beam
As shown in (e), the region of the observation specific portion 2 has a thickness of 0.
Rectangular processing is performed on both sides of the observation specific portion 2 by sputter etching until the thickness becomes 1 μm.

In general, the resolution of the secondary electron image of the FIB depends on the ion beam current and the ion beam diameter. Further, the sputter etching rate also depends on the amount of ion beam current, and it is difficult to observe and process a minute portion. By forming a reaction product with an electron beam and coating the plasma polymerized film, the position of the reaction product can be enlarged and projected. In this manner, processing with high positional accuracy can be performed.

Hereinafter, a method for fabricating a sample of a transmission electron microscope according to a second embodiment of the present invention will be described with reference to the drawings.

FIGS. 2 (a) to 2 (e) are a plan view and a sectional view of a process of a method for preparing a sample of a transmission electron microscope according to the present invention. In the figure, 1 is a sample, and 2 is an observation specific portion.
As shown in FIG. 2A, a rectangular mark of about 5 μm is formed on the sample 1 in the vicinity of the specific observation point 2 using a laser marking device. A YAG or excimer laser is used as a laser.

Next, as shown in FIG. 2 (b), the sample 1 was 2.0 mm × 0.3 mm × 0.6 mm using a dicing saw.
Process into strips of mm.

Next, in the scanning microscope, an electron beam having an acceleration voltage of 20 kV, a beam current of 10 pA and a beam diameter of 0.1 μm, for example, is irradiated to the vicinity of the observation specific portion 2 of the sample 1 for 30 seconds, and FIG. As shown, a reaction product 3 is deposited as a marking. At this time, the diameter is about 0.1 μm
Is formed.

Next, as shown in FIG. 2D, methane gas and ethylene gas are used in a plasma polymerization film forming apparatus.
The plasma polymerization film 4 is coated.

Next, in FIB, for example, acceleration voltage 30 k
V, G of the ion beam current in the range of 10 nA to 15 pA
a Using a focused ion beam, scan over the sample
As shown in (e), the region of the observation specific portion 2 has a thickness of 0.
Rectangular processing is performed on both sides of the observation specific portion 2 by sputter etching until the thickness becomes 1 μm.

Hereinafter, a method for fabricating a sample of a transmission electron microscope according to a third embodiment of the present invention will be described with reference to the drawings.

FIGS. 3A to 3F are a process plan view and a process sectional view of a method for preparing a sample for a transmission electron microscope according to the present invention. In the figure, 1 is a sample, and 2 is an observation specific portion.
Using a dicing saw, the sample 1 shown in FIG.
As shown in FIG. 3B, 2.0 mm × 0.3 mm × 0.
Process into a 6 mm strip.

Next, as shown in FIG. 3 (c), a conductive film 6 is formed using osmium oxide in a plasma polymerized film forming apparatus.
Is coated. At this time, the conductive film 6 was formed under the conditions of a gas pressure of 8 Pa, a DC voltage of 1.3 kV, and a discharge current of 1.2 mA.
It is. An osmium film is formed as the conductive film 6 with the above gas. By coating the conductive film, a reaction product can be formed even on a sample which is easily charged.

Next, in a scanning electron microscope, for example, an acceleration voltage of 20 kV, a beam current of 10 pA, and a beam diameter of 0.1 μm
The electron beam of m is irradiated to the vicinity of the observation specific portion 2 of the sample 1 for 30 seconds, and the reaction product 3 is deposited as a marking as shown in FIG. At this time, the diameter is about 0.1
A columnar carbon film of μm is formed.

Next, as shown in FIG. 3E, methane gas and ethylene gas are used in a plasma polymerized film forming apparatus.
The plasma polymerization film 4 is coated.

Next, in FIB, for example, acceleration voltage 30 k
V, G of the ion beam current in the range of 10 nA to 15 pA
a Using a focused ion beam, scan over the sample
As shown in (f), the region of the observation specific portion 2 has a thickness of 0.
Rectangular processing is performed on both sides of the observation specific portion 2 by sputter etching until the thickness becomes 1 μm.

Hereinafter, a method for fabricating a sample of a transmission electron microscope according to a fourth embodiment of the present invention will be described with reference to the drawings.

FIGS. 4A to 4F are a process plan view and a process cross-sectional view of a method for manufacturing a sample for a transmission electron microscope according to the present invention. In the figure, 1 is a sample, and 2 is an observation specific portion.
As shown in FIG. 4A, a rectangular mark 5 of about 5 μm is formed in the vicinity of the observation specific portion 2 of the sample 1 using a laser marking device. Next, as shown in FIG. 4B, the sample 1 was 2.0 mm × 0.3 mm ×
Process into a strip of 0.6 mm.

Next, as shown in FIG. 4 (c), a conductive film 6 was formed using osmium oxide in a plasma polymerized film forming apparatus.
Is coated. At this time, the conductive film 6 was formed under the conditions of a gas pressure of 8 Pa, a DC voltage of 1.3 kV, and a discharge current of 1.2 mA.
It is. An osmium film is formed as the conductive film 6 with the above gas.

Next, in a scanning electron microscope, for example, an acceleration voltage of 20 kV, a beam current of 10 pA, and a beam diameter of 0.1 μm
The electron beam of m is irradiated to the vicinity of the observation specific portion 2 of the sample 1 for 30 seconds to deposit the reaction product 3 as a marking as shown in FIG. At this time, the diameter is about 0.1
A columnar carbon film of μm is formed.

Next, using a methane gas and an ethylene gas in a plasma polymerization film forming apparatus, as shown in FIG.
The plasma polymerization film 4 is coated.

Next, in FIB, for example, acceleration voltage 30 k
V, G of the ion beam current in the range of 10 nA to 15 pA
a Scanning over the sample using the focused ion beam
As shown in (f), the region of the observation specific portion 2 has a thickness of 0.
Rectangular processing is performed on both sides of the observation specific portion 2 by sputter etching until the thickness becomes 1 μm.

Hereinafter, a method for preparing a sample for a transmission electron microscope according to the fifth embodiment of the present invention will be described with reference to the drawings.

FIGS. 5A to 5F are a process plan view and a process cross-sectional view of a method for preparing a sample for a transmission electron microscope according to the present invention. In the figure, 1 is a sample, and 2 is an observation specific portion.
As shown in FIG. 5B, the conductive film 6 is coated with osmium oxide in the plasma polymerization film forming apparatus. An osmium film is formed as the conductive film 6 with the above gas.

Next, the sample 1 was prepared using a dicing saw.
As shown in FIG. 5C, 2.0 mm × 0.3 mm × 0.
Process into a 6 mm strip.

Next, in a scanning electron microscope, for example, an acceleration voltage of 20 kV, a beam current of 10 pA, and a beam diameter of 0.1 μm
The electron beam of m is irradiated to the vicinity of the observation specific portion 2 of the sample 1 for 30 seconds to deposit the reaction product 3 as a marking as shown in FIG. At this time, the diameter is about 0.1
A columnar carbon film of μm is formed.

Next, using a methane gas and an ethylene gas in a plasma polymerization film forming apparatus, as shown in FIG.
The plasma polymerization film 4 is coated.

Next, in FIB, for example, acceleration voltage 30 k
V, G of the ion beam current in the range of 10 nA to 15 pA
a Using a focused ion beam, the sample was scanned and
As shown in (f), the region of the observation specific portion 2 has a thickness of 0.
Rectangular processing is performed on both sides of the observation specific portion 2 by sputter etching until the thickness becomes 1 μm.

Hereinafter, a method for preparing a sample for a transmission electron microscope according to the sixth embodiment of the present invention will be described with reference to the drawings.

FIGS. 6A to 6F are a process plan view and a process cross-sectional view of a method for manufacturing a sample for a transmission electron microscope according to the present invention. In the figure, 1 is a sample, and 2 is an observation specific portion.
As shown in FIG. 6A, the conductive film 6 is coated with osmium oxide in the plasma polymerized film forming apparatus. The conditions for forming the conductive film 6 at this time are a gas pressure of 8 Pa, a DC voltage of 1.3 kV, and a discharge current of 1.2 mA. Conductive film 6
With the above gas, an osmium film is formed.

Next, as shown in FIG. 6B, a rectangular mark 5 of about 5 μm is formed on the sample 1 in the vicinity of the specific observation point 2 using a laser marking device.

Next, as shown in FIG. 6C, the sample 1 was 2.0 mm × 0.3 mm × 0.6
Process into strips of mm.

Next, in a scanning electron microscope, for example, an acceleration voltage of 20 kV, a beam current of 10 pA, and a beam diameter of 0.1 μm
The electron beam of m is irradiated to the vicinity of the observation specific portion 2 of the sample 1 for 30 seconds to deposit the reaction product 3 as a marking as shown in FIG. At this time, the diameter is about 0.1
A columnar carbon film of μm is formed.

Next, using a methane gas and an ethylene gas in a plasma polymerization film forming apparatus, as shown in FIG.
The plasma polymerization film 4 is coated.

Next, in FIB, for example, acceleration voltage 30 k
V, G of the ion beam current in the range of 10 nA to 15 pA
a Scanning over the sample using the focused ion beam
As shown in (f), the region of the observation specific portion 2 has a thickness of 0.
Rectangular processing is performed on both sides of the observation specific portion 2 by sputter etching until the thickness becomes 1 μm.

In each of the above embodiments of the present invention,
Although a sample without a pattern has been described, a similar effect can be obtained with a sample on which a pattern is formed.

Further, in each of the above embodiments of the present invention, the osmium film has been described as the conductive film. However, the same effect can be obtained with a gold or platinum film.

[0052]

According to the method for preparing a sample of a transmission electron microscope of the present invention, a specific portion to be observed can be easily identified by FIB, and a TEM observation and a structural analysis of a minute portion or a minute foreign substance can be performed.
From this, it is expected that various failure mechanisms can be elucidated, and furthermore, the cause of failure can be quickly fed back to materials and device manufacturing processes and development processes, and the effects on materials and devices with stable yields or early development can be expected. .

[Brief description of the drawings]

FIGS. 1A and 1B are a process plan view and a process cross-sectional view illustrating a method for manufacturing a sample of a transmission electron microscope according to a first embodiment of the present invention.

FIGS. 2A and 2B are a process plan view and a process cross-sectional view illustrating a method for manufacturing a sample of a transmission electron microscope according to a second embodiment of the present invention.

FIG. 3 is a process plan view and a process cross-sectional view illustrating a method for manufacturing a sample of a transmission electron microscope according to a third embodiment of the present invention.

FIG. 4 is a process plan view and a process cross-sectional view illustrating a method for manufacturing a sample of a transmission electron microscope according to a fourth embodiment of the present invention.

FIGS. 5A and 5B are a process plan view and a process cross-sectional view illustrating a method for manufacturing a sample of a transmission electron microscope according to a fifth embodiment of the present invention.

FIG. 6 is a process plan view and a process cross-sectional view illustrating a method for manufacturing a sample of a transmission electron microscope according to a sixth embodiment of the present invention.

FIG. 7 is a process chart showing a conventional transmission electron microscope observation method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sample 2 Observation specific place 3 Reaction product 4 Plasma polymerization film 5 Mark 6 Conductive film

Claims (7)

[Claims] 1. A step of slicing a sample having a specific location observed by a transmission electron microscope by dicing saw processing, irradiating an electron beam near the specific observation location of the sample to deposit a reaction product, A sample preparation method for a transmission electron microscope, comprising: a step of coating a sample with a plasma-polymerized film; and a step of scanning the sample with a focused ion beam and sputter-etching an observation specific portion to a thickness of 0.1 μm. Method. 2. A step of laser-marking a sample having a specific portion observed by a transmission electron microscope, a step of thinning the sample by dicing saw processing, and irradiating an electron beam to a vicinity of the specific portion of the sample observed and reacting the sample. A step of depositing a product, a step of coating the sample with a plasma-polymerized film, and a step of scanning the sample with a focused ion beam and sputter-etching a specific observation location to a thickness of 0.1 μm. Characteristic method of preparing transmission electron microscope samples. 3. A step of slicing a sample having a specific portion observed by a transmission electron microscope by dicing saw processing, a step of forming a conductive film on the sample, and irradiating an electron beam to the vicinity of the specific portion of the sample observed. And depositing a reaction product, coating the sample with a plasma-polymerized film, and scanning the sample with a focused ion beam to sputter etch a specific observation location to a thickness of 0.1 μm. A method for preparing a sample for a transmission electron microscope, comprising: 4. A step of laser marking a sample having a specific portion observed by a transmission electron microscope, a step of thinning the sample by dicing saw processing, a step of forming a conductive film on the sample, and a step of A step of irradiating an electron beam in the vicinity of the specific observation area to deposit a reaction product, a step of coating the sample with a plasma polymerized film, and a step of scanning the sample with a focused ion beam so that the specific observation area has a thickness of 0. 1μ
and sputter etching to a thickness of m. 5. A step of forming a conductive film on a sample having a specific location observed by a transmission electron microscope, a step of thinning the sample by dicing saw processing, and irradiating an electron beam near the specific observation location of the sample. And depositing a reaction product, coating the sample with a plasma-polymerized film, and scanning the sample with a focused ion beam to sputter etch a specific observation location to a thickness of 0.1 μm. A method for preparing a sample for a transmission electron microscope, comprising: 6. A step of forming a conductive film on a sample having a specific portion observed by a transmission electron microscope, a step of laser marking the sample, a step of thinning the sample by dicing saw processing, A step of irradiating an electron beam in the vicinity of the specific observation area to deposit a reaction product, a step of coating the sample with a plasma polymerized film, and a step of scanning the sample with a focused ion beam so that the specific observation area has a thickness of 0. 1μ
and sputter etching to a thickness of m. 7. Os, Au, or Pt as a conductive film
7. The method for preparing a sample for a transmission electron microscope according to claim 3, wherein: