JPH07209155A - Sample preparing device and method - Google Patents

Abstract

PURPOSE:To easily determine the thickness of a sample at the time of polishing and to prepare a sample by a dimple grinder and by ion milling. CONSTITUTION:A sample 2 is stuck to a transparent plate 4 and a dimple grinder 1 for performing concave polishing of the sample and optical microscopes 5 to 7 for observing the polishing state of the sample are provided below the sample. The thin films on a plurality of substrates are opposedly stuck to each other and sliced, a marker is drawn on an observation position, the dummy of a transparent member is stuck to it, cutting is made with a constant width, sticking is made to half-moon-shaped mesh, wires are arranged on a flat plate and are fixed and then resin is injected for curing, plane polishing was made up to a location near the center of wires after cutting, particles and resin are mixed and then compressed under a high pressure for curing, polishing is performed in a flat plate-shape and punching is carried out, and then polishing is made by the dimple grinder, and further ion milling is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample observing apparatus and method for preparing a sample for observing a transmission image by performing preliminary polishing and ion polishing.

[0002]

2. Description of the Related Art FIG. 8 is a diagram for explaining a procedure for preparing a material-based sample, and FIG. 9 is a diagram for explaining a method for obtaining a center thickness of a sample.

The sample preparation procedure for TEM observation of samples of semiconductors, ceramics, etc. is as follows. First, as shown in FIG. 8, a sample is cut out using a precision low-speed cutting machine, and the cut-out material is roughly polished before it is cut. Is punched to 3 mmφ with a disc punch or an ultrasonic disc cutter, and precision polishing, polishing with a dimple grinder, ion polishing with a milling device or electrolytic polishing device, and electrolytic polishing are performed.

Transmission electron microscope (T
In the case of producing a sample of (EM), the center of the sample is pre-polished with a dimple grinder and the thickness of the center sample is set to 1
It is desirable to set it to 0 μm or less. In such sample preparation, after pasting the sample on the glass conventionally,
Polishing is performed with a dimple grinder, and the center thickness H at this time is, as shown in FIG. 9 using a micrometer of an optical microscope, a center height h ₃ and both end heights h ₁ ,
Average of h ₂ differences

[0005]

[Equation 1] Seeking in.

Further, even before the preliminary polishing by the dimple grinder, various methods are actually adopted as follows depending on the type of sample such as thin film, powder, wire and the like.

FIG. 10 is a diagram for explaining a conventional sample preparation method for observing a cross section of a thin film or IC, and FIG. 11 is a diagram for explaining a conventional sample preparation method for observing a cross section of an IC pattern or the like. Figure 12: Focused ion beam system (FIB)
FIG. 13 is a diagram for explaining a conventional example in which a specific portion is thinned by, and FIG. 13 is a diagram for explaining a conventional example in which a powder sample is thinned.

When observing a cross section of a thin film (sputtering, vapor deposition film, etc.) or an IC, one method is to sandwich a dummy 63 from both sides and attach a sample 61 on a substrate 62,
The bonded surface of the sliced sample 61 as shown in FIG. 10A is subjected to concave surface polishing by a dimple grinder and ion milling to make a hole in the sample as shown in FIG. TEM for a sufficiently thin part
I'm observing. In addition, as another method, FIG.
As shown in (a) and (b), the sample 71 to be observed is made to face each other and bonded, and the plates of the dummy 72 are further bonded to both outer sides thereof to form the box-shaped 73 as shown in FIG. 11 (c). FIG. 11 focusing on the sample bonding surface
As shown in (d), a brass pipe 74 is punched into a cylindrical shape.
Then, as shown in FIG.
After cutting to an appropriate thickness of about 100 μm, FIG.
As shown in (e), polishing with a dimple grinder is performed in the same manner as above.

When thinning a specific portion with a focused ion beam device (FIB), first, when a portion to be observed such as a defective portion is found, marking is performed with a laser or an ion beam as shown in FIG. 12 (a). After doing 72,
As shown in FIGS. 12B and 12C, the dicing saw 73
It cuts out and is made into blocks. And FIG.
As shown in (d), a specific portion is thinned by FIB and observed by TEM.

When it is desired to observe the longitudinal section of the wire rod sample,
If the diameter is very small, less than 2mmφ,
Although a sample is prepared by ion milling, it is difficult to accurately perform polishing with a dimple grinder in the preceding stage with one wire, so it is necessary to bond a plurality of wire rod samples together.

When thinning a powder sample by ion milling, powder is mixed with resin as shown in FIG. 13 (a) and the mixture 81 is mixed as shown in FIG. 13 (b). The pipe 82 is packed and hardened, and is cut into an appropriate thickness of, for example, about 50 μm to 100 μm as shown in FIG. 13C, and then flat-polished and dimple grinder shown in FIGS. 13D and 13E. Preliminary polishing with 83 is performed, and ion milling is performed.

[0012]

However, in the conventional sample preparation method, the time for subsequent ion etching is minimized by making the sample thickness as small as possible by polishing the sample in a concave shape with a dimple grinder. However, there is no way to know the exact sample thickness in a short time in a non-destructive manner because the sample is pasted on glass with wax.

In the measurement by the above-mentioned conventional method, it is estimated that the thickness of the wavelength level of light is such that the interference fringes can be seen by the incident light of the optical microscope as the ideal thickness of the sample. However, this thickness is on the verge of sample failure, and stopping the polishing here requires considerable experience. Further, although the thickness is measured a plurality of times, there is a problem that the error becomes large unless the same place is measured each time.

In addition, the above-mentioned conventional sample preparation method has various problems. For example, when you want to observe a cross-section of a specific part such as a failure location, the above-mentioned conventional method makes it difficult to observe due to the small area to be observed, and the dicing saw is used as a thinning method to cut out a wafer such as silicon or gallium arsenide. Too expensive to use. In the case of the wire rod sample, the deformation is particularly strong when the wire rod is made of a metal, so that it is very difficult to attach the wire rod, and in the case of the powder sample, it is shown in FIGS. As resin 91
In many cases, the powder sample 92 is lost due to etching from the portion of.

The present invention is intended to solve the above-mentioned problems, and it is possible to easily know the thickness of a sample during polishing and to secure an observable region of the sample. It is intended to provide.

[0016]

To this end, the sample preparation apparatus of the present invention comprises a dimple grinder for adhering a sample on a transparent plate and polishing the sample with a concave surface, and observing the polished state of the sample below the sample. And an optical microscope that does this.

Further, the sample preparation method is such that a marker is drawn on a transparent plate and the sample is pasted, the thickness of the sample is observed by the marker with the transmitted light of the sample and the sample is polished to observe the transmitted image. A thin film on a plurality of substrates is laminated to face each other, sliced, polished with a dimple grinder, a marker is drawn on the observation site, a dummy of a transparent member is stuck on it, and cut out with a constant width After cutting and polishing from one side to the position of the marker, polishing is performed from the other side by a dimple grinder, and further ion milling is performed. Also,
Draw a marker on the observation site and cut it out with a certain width and attach it to a half-moon mesh, and after polishing with a dimple grinder to near the position of the marker, thin it with an ion beam and sample for observation of a specific site Characterized in that the wire rods are arranged side by side on a flat plate and fixed, resin is injected and cured, cut out and subjected to planar polishing to the vicinity of the center of the wire rod, and then polishing with a dimple grinder from the opposite side of the planar polishing. A sample for observing the cross section of the wire and the powder by ion-milling after mixing the powder with resin and then compressing it under high pressure to harden it, polishing it into a flat plate, punching it, polishing with a dimple grinder Is produced.

[0018]

In the sample preparation apparatus of the present invention, since the sample is attached on the transparent plate and the sample is concavely polished, the dimple grinder and the optical microscope for observing the polished state of the sample are provided below the sample. While polishing the sample, the change in the thickness of the optical microscope can be observed at the same time.

Further, in the sample preparation method, a marker is drawn on a transparent plate, the sample is attached, and the thickness of the sample is viewed by the marker through the transmitted light of the sample, so that the thickness can be easily determined. Laminating thin films on multiple substrates facing each other,
Slice and polish with a dimple grinder, draw a marker on the observation site and attach a dummy of a transparent member on it and cut out with a constant width, cut from one side to the position of the marker, after polishing, then from the other Since polishing with a dimple grinder and ion milling are performed, a sample such as a thin film that can be easily observed can be manufactured.

A marker is drawn on the observation site, cut out with a constant width and attached to a half-moon mesh, and after polishing to a position near the marker with a dimple grinder, a thin film is formed with an ion beam. A sample for observing a specific portion can be prepared without using.

Then, the wire rods are arranged and fixed on a flat plate, resin is injected and cured, cut out and subjected to plane polishing to the vicinity of the central portion of the wire rod, and then polishing with a dimple grinder from the opposite side of the plane polishing to obtain powder. The body is mixed with resin, then compressed under high pressure to harden, polished into a flat plate, punched, polished with a dimple grinder, and further ion milled, making it easy to observe samples for observing wire cross sections and powders. Can be manufactured.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an example of a method for producing an observation sample by a transmission electron microscope according to the present invention, and FIG. 2 is a diagram for explaining another example of a thickness measuring method at the time of producing an observation sample. In the figure, 1 is a dimple grinder, 2 is a sample,
3 is wax, 4 and 8 are glass, 5 is a half mirror, and 6
Is a light source, 7 is an optical microscope objective lens, and 9 is a marker.

In FIG. 1, a sample 2 is fixed by adhering it to a glass 4 with a wax 3 and polishing it from the top to a predetermined thickness with a dimple grinder 1 until a hole is further opened. Ion milling is performed, and the periphery thereof is used as an observation part by a transmission electron microscope. Half mirror 5, light source 6, optical microscope objective lens 7
Is installed below the side opposite to the side to be polished by the dimple grinder 1 and monitors the thickness of the sample being polished. The laser from the light source 6 through the half mirror 5 to the glass 4 and the sample 2 from below. The monochromatic light is emitted, and the reflected light is received by the optical microscope objective lens 7 through the half mirror 5 to monitor it by an eye or a TV monitor and automatically stop the polishing by detecting the contrast.

When the light source 6 such as a laser or monochromatic light and the optical microscope are arranged below the sample 2 as described above, the sample is observed by the optical microscope as the thickness of the sample becomes thin due to polishing by the dimple grinder 1. The image of the transmitted light gradually increases. Then, when it becomes extremely thin and reaches the wavelength level of the light, the interference fringes can be observed by the incident light. The thickness at this time becomes an ideal thickness. Such a change in thickness can be observed in real time. Therefore, the observing method in this case includes observing with eyes through an eyepiece lens, observing with a television monitor, and determining whether or not to interrupt the polishing by automatically detecting the contrast by image processing. May be controlled. In the conventional polishing with the dimple grinder, the optical microscope was incorporated above, so it was necessary to remove the wheel of the dimple grinder at the time of observation, but as in the present invention, the optical microscope was incorporated below the sample. By performing image processing and judgment, it becomes possible to observe the sample in real time during polishing, and it becomes unnecessary to know the thickness of the wax and the empirical feeling of interrupting polishing.

As a method for measuring the thickness of the sample, one or more linear or dot-like markers 9 may be drawn on the surface of the glass 8 to which the sample is attached as shown in FIG. Good. As the polishing progresses, this marker 9 can be seen by the transmitted light through the sample. This allows height measurement with the center always at the same position. Further, when the refractive index of the sample is known in advance, the center thickness of the sample can be calculated from the difference in the focus amount between the surface and the marker, and the error can be further reduced. The marker may have a shape other than the linear shape or the dot shape, or may be drawn only on the central portion or on the entire surface.

FIG. 3 is a diagram showing an embodiment of a sample preparation method according to the present invention for observing a cross section of a thin film, an IC or the like, and FIG.
FIG. 3 is a diagram showing an example of a sample manufacturing method according to the present invention for observing a cross section of a specific portion such as an IC. 11 in the figure
Is a thin film, 12 is a substrate, 13 and 22 are dummy, 21 is a sample, 23 is an optical microscope, 24 is a dimple grinder, and 25 is a marker.

A sample preparation method for TEM observation of thin films, ICs and the like is as follows. First, as shown in FIG. 3A, a plurality of sets are attached so that the thin films 11 formed on a substrate 12 face each other. They are laminated together, and a dummy 13 is attached to the outer side thereof, and then sliced. And FIG.
After polishing to a predetermined thickness with a dimple grinder in the range shown by the dotted line in (b), ion etching is performed until a hole is opened as shown in FIG. 3 (b). Thereby, the periphery of the edge of the hole becomes an observable portion. By stacking a plurality of thin samples in this way, a wide observable region after ion etching can be secured.

Further, in the sample preparation method for observing a cross section of a specific portion such as an IC pattern, first, as shown in FIG. 4A, a cross-shaped marker 25 is drawn on the portion of the sample 21 where the cross section is to be observed, and the cross marker 25 is drawn. As shown in FIG. 4B, a dummy 22 made of transparent glass or the like is attached to the top. Next, FIG.
Cut near the cross marker 25 as shown in (c),
While observing with the optical microscope 23 as shown in FIG. 4D, it is cut and polished as shown in FIG. At this time, since a transparent material such as glass is stuck on the sample, it is possible to confirm that a specific portion appears on the surface by polishing while observing with an optical microscope. Therefore, as shown in FIG. 4 (f), with a specific portion facing downward, as shown in FIG. 4 (g), a dimple grinder 24 is used to grind to a predetermined thickness, and then a hole is opened as shown in FIG. 4 (h). Perform ion milling until. Since the dummy is made of a transparent material as described above, it is possible to perform planar polishing while confirming the position of the specific portion.

FIG. 5 is a diagram for explaining one embodiment of a sample manufacturing method for thinning a specific portion, 31 is a sample,
32 is a mesh, and 33 is a dimple grinder.

When thinning a specific portion for observation, a dimple grinder 33 as shown in FIG. 5 is used instead of the conventional dicing saw. In this case, first, as shown in FIG. 5 (a), the sample 31 is cut out to a width of about 0.5 mm including a specific portion, and then, as shown in FIG.
As shown in (b) and (c), the sample 31 is attached onto the single-hole mesh 32 cut into a half moon shape. Then, it is attached to a polishing glass or the like with wax or the like, and a dimple grinder 33 is applied as shown in FIG. 5 (d) to form a block with a width of 20 μm or less. Further, as shown in FIG. A beam device (FIB) is used to thin the film (hatched portion) and TEM observation is performed.

Generally, a dicing saw is rarely owned by anyone other than a semiconductor maker, whereas a dimple grinder is normally owned in a place where TEM sampling is performed. Therefore, a simple preparation for FIB processing should be performed. You can Further, by making the ring half-moon shaped, it becomes easy to observe the progress in the middle with an optical microscope or an electron microscope.

FIG. 6 is a diagram for explaining one embodiment of the method for preparing a wire sample, and FIG. 7 is a diagram for explaining one embodiment of the method for preparing a powder sample, where 41 is a wire and 42 is Board, 4
3 is a clip, 44 is a ring, 45 and 55 are dimple grinders, 51 is a resin / sample mixture, 52 is a ring, 53 is a compressor, and 54 is a punched sample.

When observing the longitudinal section of the wire rod sample, the wire rods 41 are lined up as shown in FIGS. 6 (a) and 6 (b), and both ends are fixed on the flat plate 42 by the clips 43, and the resin is poured. To cure. Then, as shown in FIGS. 6C and 6D, the sample 41 arranged in a plate shape by curing the resin is cut and attached to the ring 44, and as shown in FIG.
The top surface is polished to about half of the surface. After that, FIG. 6 (f)
Dimple grinder 4 from the opposite bottom as shown in
Polishing to a predetermined thickness is carried out with No. 5, followed by ion milling as shown in FIG. Since the wire rods are arranged on the flat plate and cured with the resin in this manner, the sample of the wire rods can be adhered to each other without any gap and polished to thin the observation site.

In the case of a powder sample, first, as shown in FIG.
As shown in (b), a resin / sample mixture 51 of a powder sample and a resin is placed in a ring 52, and as shown in FIG. 7 (c), a high pressure device 53 compresses the high pressure (100 to 300 kg / cm).
² ), and then heat curing or natural curing depending on the type of resin. Then, as shown in FIGS. 7 (d) and 7 (e), it is ground into a flat plate shape and punched to have a diameter of 3 mm.
As shown in (f), the dimple grinder 55 is used to polish to a predetermined thickness, and then ion milling is performed. By performing high-pressure compression and hardening treatment in this way, defoaming is effectively performed in the mixture of the powder sample and the resin,
Moreover, since the powder is packed at a high density, the resin portion can be etched first and the sample can be prevented from being lost even during ion milling.

[0035]

As is apparent from the above description, according to the present invention, since the dimple grinder for polishing the sample on the concave surface and the optical microscope for observing the polishing state of the sample are provided below the dimple grinder, the polishing of the sample is performed. At the same time, you can see the change in thickness of the optical microscope. Further, in the sample preparation method, a marker is drawn on a transparent plate, the sample is attached, and the thickness of the sample is viewed by the marker by the transmitted light of the sample, so that the thickness can be easily determined. Laminating thin films on multiple substrates facing each other, slicing and polishing with a dimple grinder, drawing a marker on the observation site and attaching a dummy of a transparent member on it and cutting it out with a certain width, from one side After cutting and polishing to the position of the marker, polishing with a dimple grinder from the other side and further ion milling, a sample such as a thin film that can be easily observed can be prepared.

A marker is drawn on the observation site, cut out with a constant width, and attached to a half-moon mesh. After polishing with a dimple grinder to the vicinity of the marker, a thin film is formed with an ion beam. A sample for observing a specific portion can be prepared without using.

Then, the wire rods are arranged and fixed on a flat plate, resin is injected and cured, cut out and subjected to plane polishing to the vicinity of the center of the wire rod, and then polishing with a dimple grinder from the opposite side of the plane polishing to obtain a powder. The body is mixed with resin, then compressed under high pressure to harden, polished into a flat plate, punched, polished with a dimple grinder, and further ion milled, making it easy to observe samples for observing wire cross sections and powders. It is possible to prevent the powder sample from being lost.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a method for producing an observation sample by a transmission electron microscope according to the present invention.

FIG. 2 is a diagram for explaining another example of the thickness measuring method at the time of preparing an observation sample.

FIG. 3 is a diagram showing an example of a sample manufacturing method according to the present invention for observing a cross section of a thin film, an IC, or the like.

FIG. 4 is a diagram showing an example of a sample manufacturing method according to the present invention for observing a cross section of a specific portion such as an IC.

FIG. 5 is a diagram for explaining one example of a sample manufacturing method for thinning a specific portion.

FIG. 6 is a diagram for explaining one example of a method for preparing a sample of a wire rod.

FIG. 7 is a diagram for explaining one example of a method for preparing a powder sample.

FIG. 8 is a diagram for explaining a procedure for preparing a material-based sample.

FIG. 9 is a diagram for explaining a method for obtaining the center thickness of a sample.

FIG. 10 is a diagram for explaining a conventional sample preparation method for observing a cross section of a thin film, an IC, or the like.

FIG. 11 is a diagram for explaining a conventional sample manufacturing method for observing a cross section of an IC pattern or the like.

FIG. 12 is a diagram for explaining a conventional example in which a specific portion is thinned by a focused ion beam device (FIB).

FIG. 13 is a diagram for explaining a conventional example in which a powder sample is made into a thin film.

FIG. 14 is a diagram for explaining the problem of powder sample loss.

[Explanation of symbols]

1 ... Dimple grinder, 2 ... Sample, 3 ... Wax, 4, 8 ... Glass, 5 ... Half mirror, 6 ... Light source, 7
… Optical microscope objective lens, 9… Marker

Claims (7)

[Claims] 1. A sample preparation comprising a dimple grinder for sticking a sample on a transparent plate and polishing the sample with a concave surface, and an optical microscope below the sample for observing the polished state of the sample. apparatus. 2. A marker is drawn on a transparent plate and the sample is attached, and the sample is polished by observing the thickness of the sample with the marker by the transmitted light of the sample to prepare a sample for transmission image observation. Characteristic sample preparation method. 3. A thin film on a plurality of substrates is bonded to face each other, sliced and polished by a dimple grinder, and further ion milled to prepare a sample for observing a cross section of the thin film or the like. A method for preparing a sample. 4. A marker is drawn on an observation site, a dummy of a transparent member is stuck on the marker and cut out with a constant width, and after cutting and polishing from one side to the position of the marker, polishing with a dimple grinder from the other side. A method for preparing a sample, which comprises performing ion milling and further preparing a sample for observing a cross section of a specific portion. 5. A marker is drawn on the observation site, cut out with a constant width and attached to a half-moon mesh, and after polishing with a dimple grinder to the vicinity of the position of the marker, a thin film is formed with an ion beam to remove the specific region. A method for preparing a sample, which comprises preparing a sample for observation. 6. Wires are arranged side by side on a flat plate, resin is injected and cured, cut out and subjected to surface polishing to near the center of the wire, and then polishing with a dimple grinder from the opposite side of the surface polishing, and A method for preparing a sample, which comprises performing a sample for observing a cross section of a wire by performing ion milling. 7. A sample for observing the powder by observing the powder by mixing the powder with a resin, followed by compression under high pressure to cure, polishing into a flat plate shape, punching, polishing with a dimple grinder, and further ion milling. A method for preparing a sample, which comprises manufacturing the sample.