JPH06132001A - Sheet mesh, and sample and its formation for transmission electron microscope - Google Patents

Abstract

(57) [Summary] [Purpose] Make the ion beam irradiated on the sample uniform,
Provide a sheet mesh capable of polishing a wide range. [Structure] By forming a tapered portion 11b at the edge of the central opening 11a of the disk-shaped sheet mesh 11 so that the ion beam B does not hit the edge, a wide range of sample surfaces can be polished and the beam disturbance can be improved. Prevents flow from occurring and enables uniform polishing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a transmission electron microscope (TEM).
The present invention relates to a sheet mesh for supporting a sample used in a Microscope) and a method for preparing the sample.

[0002]

2. Description of the Related Art Conventionally, as a means for evaluating the fine structure of a semiconductor device, observation with a transmission electron microscope from the cross-sectional direction of the device has been performed. The sample observed with this transmission electron microscope is, for example, two semiconductor substrates 1 and 1 shown in FIG.
As shown in (A), the laminated films 2 are faced to each other and bonded with an adhesive 3, and a thin plate a is cut out. Next, FIG.
As shown in (B), the thin plate a is adhered to the polishing rotator 4 with the adhesive 5 and is rotationally polished with the polishing powder 6 to have a thickness of 20.
Thin to about μm and mirror-finish both sides. Then
The thin plate a thus thinly processed is shown in FIG.
As shown in FIG. 3, the hole 7a is formed in the central part of the metallic single hole mesh (sheet mesh) having a thickness of several 10 μm.
14a is fixed so as to cover a and mounted on the rotary support 8 as shown in FIG. 14D, and Ar ⁺ ions generated by high-voltage discharge in a vacuum are accelerated to accelerate the thin plate a at an irradiation angle of 9 to 20 °. The ion beam B is irradiated onto the thin plate a, and the ion irradiation is stopped when there is a small hole in the center of the thin plate a. In this way, a transmission electron microscope sample can be prepared.

[0003]

However, according to such a conventional method for producing a sample for a transmission electron microscope, as shown in FIG. 15, Ar ⁺ incident from an oblique direction is used.
As shown in FIG. 16, the periphery of the lower surface of the thin plate (sample) a facing the hole 7a when the ion beam B collides with the edge of the opening of the single-hole mesh 7 is not much polished and is close to the edge. There is a problem that uneven polishing and surface roughness occur due to the turbulent flow generated in 1., and the polishing is not performed properly.

Further, according to such a conventional method for producing a sample for a transmission electron microscope, the adhesive 3 does not work depending on the material of the laminated film 2 of the sample to be polished, and the subsequent polishing step cannot proceed. There was a problem. Examples of the non-adhesive material include Al.

Further, according to such a conventional method for producing a sample for a transmission electron microscope, it is difficult to arrange the thin plate a so that the laminated film 2 which is an observation target portion is located at the center of the hole 7a, and it is generally. As shown in FIG. 17, the laminated film 2 has holes 7
There is a problem in that the laminated film 2 portion, which is the portion to be observed and is fixed while being displaced from the center of a, is not polished well as shown in FIG. 17 (B).

The problem to be solved by the present invention is, what kind of means should be taken to obtain a method for preparing a sheet mesh and a transmission electron microscope sample in which an ion beam is uniformly irradiated over a wide range of the sample. There is a point. Moreover, what kind of means should be used to ensure the adhesion of the sample? Furthermore, what kind of means should be taken to strictly arrange the laminated film (observed film) at the center of the sheet mesh.

[0007]

The invention according to claim 1 is
In a sheet mesh having an opening in the center and supporting the sample for a transmission electron microscope so as to cover the opening, the edge portion of the opening is formed in a tapered shape. , As a solution.

The invention according to claim 2 is characterized in that the taper of the edge portion is set to the same angle as the irradiation angle of the sample polishing energy beam.

According to a third aspect of the present invention, there is provided a sheet mesh which has an opening in the center and supports the sample in a state where the sample for a transmission electron microscope is placed so as to cover the opening. It is characterized in that a concave portion is formed in the supporting region and the sample is fitted into the concave portion.

According to the fourth aspect of the invention, the sample is supported on a sheet mesh having an opening at the center and the edge of the opening is formed in a tapered shape, and the sample is polished with an energy beam. It is a solution.

According to a fifth aspect of the invention, a sheet mesh is used in which the taper of the edge portion is the same as the irradiation angle of the energy rays.

According to a sixth aspect of the present invention, the sample is fitted into the recess of a sheet mesh having an opening in the center and a recess is formed in a region for supporting the sample, and the sample is polished with energy rays. Is the solution.

According to a seventh aspect of the present invention, a substrate having a laminated film formed on the surface of at least one of the substrates is adhered so as to sandwich the laminated film to prepare a sample, and the sample is cut and polished. In the method for producing a sample for a transmission electron microscope by performing the method, after forming an adhesive layer having high adhesiveness to the laminated film and the adhesive on the laminated film, the adhesive is attached to the surface of the adhesive layer. The solution is to perform the adhesion.

The invention according to claim 8 has an adhesive layer sandwiching an adhesive layer, a laminated film is provided outside the adhesive layer, and a substrate is provided outside the laminated film. I am trying.

According to a ninth aspect of the present invention, in a sheet mesh having an opening in the center and supporting the sample for a transmission electron microscope placed on the opening so as to cover the opening, the opening is provided. The solution means is to provide a means for positioning the sample for the transmission electron microscope with respect to.

According to a tenth aspect of the present invention, the positioning means is a line extending toward the center, which is formed around the opening.

The invention according to claim 11 is characterized in that the positioning means is a concave portion into which the transmission electron microscope sample is fitted.

According to a twelfth aspect of the present invention, a transmission electron microscope sample is supported on a sheet mesh having an opening at the center and a line directed toward the center is formed around the opening, and the sample is attached to the sheet mesh. Polishing with energy rays is the solution.

According to a thirteenth aspect of the present invention, a transmission electron microscope sample is fitted and supported in the recess of a sheet mesh having an opening in the center and a recess for positioning.
Polishing the sample with energy rays is the solution.

[0020]

In the invention according to claims 1 to 6 of this application, the edge portion of the opening of the sheet mesh is tapered so that the sample surface facing the opening is uniformly irradiated with the energy beam for sample polishing. It becomes possible. In particular,
By setting the taper of the edge portion to the same angle as the irradiation angle of the energy ray, the shadow of the edge of the opening is eliminated on the sample surface, and good polishing can be performed. Further, by forming a concave portion in the sheet mesh having an opening in the center and fitting the sample into the concave portion, the step between the surface of the sheet mesh on the side where the concave portion is not formed and the sample surface becomes small, so that the sample polishing Irradiation of the energy beam onto a wide range of the sample surface suppresses the generation of turbulent flow of the energy beam, and good polishing can be performed.

Further, in the inventions according to claims 7 and 8 of this application, the substrates on which the laminated films are formed are integrated by adhering with each other by using the adhesion layer, and it is possible to cut and polish the sample. Play an action. This is particularly effective when the laminated film is a material film such as Al that does not work with an adhesive.

Further, in the inventions according to claims 9 to 13 of this application, the sample for a transmission electron microscope is provided by a line directed toward the center or a positioning recess formed around the opening of the sheet mesh. It becomes possible to arrange strictly. Therefore, the observation with the transmission electron microscope can be favorably performed.

[0023]

The details of a sheet mesh, a transmission electron microscope sample and a method for producing the same according to the present invention will be described below with reference to the examples shown in the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a sheet mesh (single hole mesh) 11 of this embodiment and a sample A placed and fixed on the sheet mesh 11. The sheet mesh 11 has a disk shape with an opening 11a formed in the center, and the sample A is placed and fixed on one surface to cover the opening 11a of the sheet mesh 11. And
A tapered portion 11b is formed around the edge portion of the opening 11a on the other surface side of the sheet mesh 11. As shown in FIG. 2, the taper angle of the taper portion 11b is as follows.
The irradiation angle of the ion beam B of argon (Ar), which is an energy ray for polishing the sample, is the same. The sample A may be prepared by the conventional method shown in FIGS.

When the sample A is polished by using the sheet mesh 11, the sheet mesh 11 is attached to the rotary support 8 as shown in FIG. 14 (D) and the ion beam B is irradiated from the ion beam irradiation means. And the rotary support 8 is rotated.

In this embodiment, as shown in FIG.
Since the ion beam B can be applied to a wide area of the sample surface without colliding with the edge of the opening 11a, the sample A can be polished well. Further, in this embodiment, since the ion beam does not hit the edge of the opening 11a, the beam flow is uniform and the sheet mesh 11 itself is not polished in the vicinity of the sample, so that the sample A is contaminated with the sheet mesh material. There is an advantage that it is hard to be done.

3 to 7 are sectional views showing modified examples of the embodiment. Sheet mesh 11 opening 11a shown in FIG.
The inner peripheral surface of is entirely tapered 11b,
The taper angle of the ion beam B is the same as in the above embodiment.
The irradiation angle is the same. Therefore, the ion beam B
No shadow is formed at all, and more uniform polishing becomes possible. The sheet mesh 11 shown in FIG. 4 has a tapered portion 11b on the entire lower surface of the sheet mesh 11, and is suitable for performing ion beam irradiation at a lower angle.
Further, in the sheet mesh 11 shown in FIG. 5, the tapered portion 11b of the sheet mesh 11 shown in FIG. 3 is used as the curved surface 11c that curves inward, and the sheet mesh 11 shown in FIG. This is an example having a surface 11d. Further, the sheet mesh 11 shown in FIG. 7 has a concave portion 11e for fitting the sample A formed on the upper surface thereof and a tapered portion 11b formed on the lower surface thereof. It has a structure that can be used for angular ion beams.

Although the present embodiment has been described above, the present invention is not limited to these, and various design changes associated with the gist of the configuration can be made.

(Second Embodiment) FIGS. 8 and 9 are sectional views of the second embodiment. In this embodiment, the adhesive 3 shown in FIG. 14 is ineffective, and the laminated film 2 which cannot be adhered is effective.

FIG. 8 shows that Si as an adhesion layer is formed on the laminated film 2 made of Al, which is an observation target portion of the transmission electron microscope.
It is a cross-sectional view of a state in which the N film 14 is coated. Up to the state where the laminated film 2 is formed on the semiconductor substrate 1, it is manufactured under a normal semiconductor device manufacturing process. The film pressure of the laminated film 2 may be the actual designed film thickness of the semiconductor device. And
A SiN film 14 is coated on the upper side of the laminated film 2.
The SiN film 14 is coated to a thickness of about 500 nm by a SiN film (passivation film) coating process using a CVD apparatus, which is performed in a normal semiconductor device manufacturing process.

By doing so, as shown in FIG. 9, since the epoxy adhesive 3 has an adhesive effect on the SiN film 14, sample adhesion, which is one step of preparing a sample for a transmission electron microscope, is possible. Becomes Therefore, by using the method shown in this example, it is possible to prepare a transmission electron microscope sample of a laminated film that cannot be adhered with an adhesive, which has been impossible in the past.

Although the present embodiment has been described for the case where the laminated film 2 is made of Al, it can be applied to the case where the laminated film 2 is made of another material. Also, the adhesion layer is not limited to SiN. Furthermore, it is possible to use an adhesive other than an epoxy adhesive. Further, although the above-mentioned embodiment is an example in which the laminated film is formed on both substrates to be adhered, the present invention can be applied even when the laminated film is formed on only one substrate.

(Embodiment 3) FIG. 10 is a plan view of a sheet mesh (single hole mesh) 12 of this embodiment, and FIG. 11 is a plan view of a state in which a sample A is placed and fixed on the sheet mesh 12. . The sheet mesh 12 has an opening 12a at the center.
Is formed into a disc shape, and by mounting and fixing the sample A on one surface, the opening 1 of the sheet mesh 12 is formed.
It is designed to cover 2a. A line 12b extending toward the center of the opening 12a is marked on the periphery of the opening 12a. As shown in FIG. 11, by placing and fixing the laminated film 2 portion of the sample A in line with the line 12b, the laminated film 2 portion is strictly arranged in the center of the opening 12a of the sheet mesh 12. The sample A is shown in FIG.
It may be manufactured by the conventional method shown in FIG.

When the sample A is polished by using the sheet mesh 12, the sheet mesh 12 is attached to the rotary support 8 as shown in FIG. 14D, and the ion beam B is irradiated from the ion beam irradiation means. And the rotary support 8 is rotated.

By the way, in the method of manufacturing a series of transmission electron microscope samples used for carrying out the present invention as shown in the prior art, the finished sample A is polished thinnest in the vicinity of the center and approaches the periphery. Therefore, the sample has a shape with an increased thickness. Therefore, when the laminated film 2 to be observed is arranged in the center of the opening 12a, the best sample in which the laminated film 2 portion is thinly and uniformly polished over a wide range can be obtained. In this embodiment, as shown in FIG. 12, it is easier to strictly arrange the laminated film 2 which is the observation target portion in the center of the opening 12a as compared with the prior art, and such arrangement is required. The advantage is that the best sample for transmission electron microscope can be obtained.

FIG. 13 shows a modification of this embodiment. Figure 1
The sheet mesh 13 shown in 3 has a concave portion 13b for positioning the sample A formed on one side surface, and it becomes easier and more accurate to dispose the laminated film 2 portion of the sample A at the center of the opening of the sheet mesh.

Although the first to third embodiments have been described above,
The present invention is not limited to these, and various design changes are possible.

[0038]

As is clear from the above description, according to the inventions described in claims 1 to 6 of this application, the flow of the ion beam becomes uniform and the ion beam hits a wide range of the sample, which is favorable. There is an effect that the sample can be polished. Moreover, the sheet mesh itself is less likely to be abraded by the energy rays, which has the effect of suppressing the occurrence of sample contamination by the sheet mesh material.

Further, according to the inventions of claims 7 and 8 of this application, it becomes possible to prepare a sample for a transmission electron microscope of a laminated film which cannot be adhered with an adhesive, which was impossible in the past. Produces the effect of

Further, according to the inventions of claims 9 to 13 of the present application, since the laminated curtain as the observation target portion can be easily arranged exactly in the center of the sheet mesh, the observation target portion can be made thin and uniform over a wide range. There is an effect that it becomes possible to polish.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of the present invention.

FIG. 2 is a sectional view of the first embodiment of the present invention.

FIG. 3 is a sectional view showing a modified example of the first embodiment.

FIG. 4 is a cross-sectional view showing a modified example of the first embodiment.

FIG. 5 is a cross-sectional view showing a modified example of the first embodiment.

FIG. 6 is a cross-sectional view showing a modified example of the first embodiment.

FIG. 7 is a cross-sectional view showing a modified example of the first embodiment.

FIG. 8 is a cross-sectional view showing a second embodiment.

FIG. 9 is a cross-sectional view showing a second embodiment.

FIG. 10 is a plan view showing a third embodiment.

FIG. 11 is a plan view showing a third embodiment.

FIG. 12 is a cross-sectional view showing a third embodiment.

FIG. 13 is a perspective view showing a modified example of the third embodiment.

14A to 14D are explanatory views showing steps of a conventional method for polishing a sample.

FIG. 15 is an explanatory diagram showing a conventional beam state.

FIG. 16 is a cross-sectional explanatory view of a conventional example.

17A and 17B are cross-sectional views of a conventional example.

[Explanation of symbols]

 A ... Sample B ... Ion beam 1 ... Semiconductor substrate 2 ... Laminated film 3 ... Adhesive 11 ... Sheet mesh 11a ... Opening 11b ... Taper 11e ... Recess 12 ... Sheet mesh 12a ... Opening 12b ... Line 13 ... Sheet mesh 13a ... Opening 13b ... Concave

Claims (13)

[Claims] 1. A sheet mesh having an opening in the center and supporting a sample for a transmission electron microscope so as to cover the opening, wherein the edge of the opening is tapered. A sheet mesh characterized by being formed into. 2. The sheet mesh according to claim 1, wherein the taper of the edge portion is the same as the irradiation angle of the sample polishing energy ray. 3. A sheet mesh having an opening in the center and supporting a sample for a transmission electron microscope so as to cover the opening, wherein a recess is provided in a region supporting the sample. A sheet mesh, which is formed and the sample is fitted into the recess. 4. A transmission electron microscope, comprising: a sheet mesh having an opening at the center, the edge of the opening being tapered; and supporting the sample, and polishing the sample with energy rays. For preparing sample for use. 5. The method for producing a sample for a transmission electron microscope according to claim 4, wherein a sheet mesh in which the taper of the edge portion is the same as the irradiation angle of the energy beam is used. 6. A transmission type, characterized in that the sample is fitted into the recess of a sheet mesh having an opening at the center and a recess is formed in a region for supporting the sample, and the sample is polished with energy rays. Method for preparing sample for electron microscope. 7. A transmissive type in which a laminated film is formed on the surface of at least one of the substrates, the substrates are adhered to each other so as to sandwich the laminated film to prepare a sample, and the sample is cut and polished. In the method for producing a sample for an electron microscope, after forming an adhesive layer having high adhesiveness to the laminated film and the adhesive on the laminated film, the adhesive is adhered to the surface of the adhesive layer for adhesion. A method for producing a sample for a transmission electron microscope, which is characterized by being performed. 8. A sample for a transmission electron microscope, comprising an adhesive layer sandwiching an adhesive layer, a laminated film outside the adhesive layer, and a substrate outside the laminated film. . 9. A sheet mesh having an opening in the center and supporting the sample for a transmission electron microscope in a state that the sample is placed so as to cover the opening, wherein the transmission electron microscope with respect to the opening is provided. A sheet mesh, characterized in that it is provided with means for positioning a sample for use. 10. The sheet mesh according to claim 9, wherein the positioning means is a line formed toward the center and formed around the opening. 11. The sheet mesh according to claim 9, wherein the positioning means is a recess into which the transmission electron microscope sample is fitted. 12. A transmission electron microscope sample is supported on a sheet mesh having an opening at the center and a line directed toward the center is formed around the opening, and the sample is polished with energy rays. A method for producing a sample for a transmission electron microscope, which comprises: 13. A transmission electron microscope sample is fitted and supported in the recess of a sheet mesh having an opening in the center and a recess for positioning, and the sample is polished with energy rays. And a method for preparing a sample for a transmission electron microscope.