KR100620728B1 - Method for Manufacturing Specimen for Analyzing by Transmission Electron Microscope - Google Patents

Abstract

According to the present invention, there is provided a method for manufacturing a specimen for TEM analysis, comprising: separating and cutting a specimen including an analysis point from a wafer into a predetermined size; Bonding the two cut specimens with epoxy; Grinding each specimen so that a width of an upper surface including an analysis point is 100 μm or less; Milling each specimen with an FIB device (ion beam focusing device) such that the width of the predetermined area including the analysis point is 1000 mm or less; And attaching two bonded specimens to a grid.

Here, the grid is formed in the shape of a disc having a through hole in the center, and a predetermined area including the milled analysis point of the specimen is located in the through hole, and the unmilled periphery of the specimen It is preferred to be supported by a grid.

According to the present invention, it is possible to increase the accuracy of the carbon analysis of the specimen, and when the specimen is initially separated from the wafer, the size of the specimen is relatively large, so that the specimen is easily separated from the wafer. In addition, since the two specimens are produced at the same time, it is possible to shorten the process time for the specimen production.

TEM, FIB, Specimen, Milling, Grid

Description

Method for Manufacturing Specimen for Analyzing by Transmission Electron Microscope

1 is a process chart showing a test piece manufacturing method for TEM analysis according to the prior art.

2 to 9 is a cross-sectional view for explaining a method for preparing a test specimen for TEM analysis according to the present invention.

<Description of Major Symbols in Drawing>

100: wafer 200: analysis point

300: grid 310: through hole

320: support portion A: milled area

B: unmilled area

The present invention relates to a method for manufacturing a Specimens for Transmission Electron Microscope (TEM) analysis, and more specifically, to a Focused ion beam (FIB) device. It relates to a method for preparing a specimen for TEM analysis.

In general, a semiconductor device is manufactured by repeatedly performing a unit process such as film formation, etching, diffusion, metal wiring, etc. to form a pattern having electrical characteristics on a semiconductor substrate. In recent years, such semiconductor devices have been highly integrated and miniaturized to realize high capacity and high speed response speed, and thus, the importance of analytical devices or technologies required for structural and chemical analysis of finer regions has been highlighted. In particular, among various analysis apparatuses, optical equipment such as a TEM is used to observe a grating image at a specific portion of a semiconductor device, and such a TEM is very useful for device characteristics and defect analysis, and provides high reliability.

On the other hand, in order to perform the characteristics and defect analysis of the device using the TEM is required to produce a test specimen for TEM analysis, such a TEM analysis specimen should be manufactured to a very thin thickness, for example, less than 1000Å. Therefore, a FIB device is generally used for fabricating a thin film size, and the FIB device is a device for thinning a thickness of a predetermined portion of a specimen by scanning an ion beam onto a predetermined portion of the specimen cut to a predetermined size.

Hereinafter, with reference to the drawings looks at the specimen manufacturing method for a TEM analysis according to the prior art.

1 is a process chart showing a manufacturing process of a specimen for a conventional TEM analysis.

Referring to FIG. 1, a mark for identifying a portion to be observed on a wafer is formed by using an ion beam. (S100) However, this step is not necessarily required, and the mark is not displayed for the convenience of the user. You can also proceed with the process.

The periphery is cut around the mark (part to be observed) displayed on the wafer. (S200)

Grinding the specimen containing the mark to a thickness of about several μm (S300).

Then, using the epoxy adhesive, the specimen is attached to a grid (S400).

In order to protect the mark area, a protective film is deposited on the mark mark (S500).

Both sides of the specimen are milled with an ion beam to form an analytical specimen including a mark, thereby completing a TEM analysis specimen having a width of 1,000 m or less (S600).

According to the manufacturing method of the specimen for TEM analysis according to the prior art has the following problems.

In general, since the specimen is attached to a grid coated with a carbon film, when analyzing the specimen using a TEM, the carbon component contained in the specimen due to the carbon film of the grid is analyzed. Will be less accurate.

In addition, the milling (milling) process using the ion beam is a very fine work, there is a problem that takes a very long time to complete one specimen.

An object of the present invention is to increase the accuracy of the analysis of carbon contained in the specimen (carbon).

Another object of the present invention is to shorten the manufacturing process time of the specimen for TEM analysis and at the same time increase the success rate of the specimen production.

According to the present invention, there is provided a method for manufacturing a specimen for TEM analysis, comprising: separating and cutting a specimen including an analysis point from a wafer into a predetermined size; Bonding the two cut specimens with epoxy; Grinding each specimen so that a width of an upper surface including an analysis point is 100 μm or less; Milling each specimen with an FIB device (ion beam focusing device) such that the width of the predetermined area including the analysis point is 1000 mm or less; And attaching two bonded specimens to a grid.

And before the milling step, it is preferable to further include forming a protective film on top of the analysis region of each specimen. The protective film is made of any one of a tungsten (W) film, a platinum (Pt) film, a carbon (C) film, and an aluminum (Al) film. The cutting of the specimen is performed by a method of forming a groove in each corner of the specimen and then applying a shock to separate the specimen from the wafer. The grid is formed in the shape of a disk having a through hole in the center, and a predetermined area including the milled analysis point of the specimen is located in the through hole, and the unmilled periphery of the specimen It is preferred to be supported by a grid. Here, the grid is made of copper (Cu) or nickel (Ni), the diameter of the disc is 3mm, the diameter of the through hole is 2.3mm or less.

Embodiment

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, a wafer 100 in which a defect is generated is selected to perform an analysis operation for determining whether a specific film is defective among a plurality of films formed on the wafer 100.

As shown in FIG. 3, the analysis point 200 is included while marking (marking) a portion 200 (hereinafter referred to as “analysis point”) 200 to be observed on the wafer 100 or observing through a microscope or the like. The specific region is cut first from the wafer 100. For example, the first cutting to have a size of about 3 × 3mm using a diamond cutter to form a specimen in which the analysis point 200 is located in the center, as shown in FIG. As described above, the size of the specimen formed by the primary cutting is relatively large, so that the specimen can be easily separated from the wafer 100.

As shown in FIG. 5, the secondary cutting is performed as close as possible to the analysis point 200 for the primary cut specimen. At this time, the analysis point 200 is cut so that it remains on the specimen.

This primary and secondary cutting is preferably made by a cleaving system (Cleaving System). Since the wafer 100 is a single crystal, a cleaving system forms grooves at each corner of a specific region to be cut, and then applies a force to the specific region of the wafer 100 to analyze the analysis point 200. This is a method for cutting the specimen.

And, as shown in Figure 6, two specimens cut in this manner are bonded using epoxy (epoxy). That is, in a state in which the surface including the analysis point 200 of each specimen is positioned to be an upper surface, one of the cut surfaces of each specimen is bonded using epoxy.

Subsequently, as shown in FIG. 7, for two specimens bonded with epoxy, the front and rear surfaces are ground. In this case, it is preferable to grind so that the width of the upper surface of each specimen including the analysis point 200 is 100 μm or less.

Subsequently, as shown in FIG. 8, for each of the two specimens bonded with epoxy, the FIB device was milled on the front and rear surfaces around the analysis point 200 located on the upper surface of the specimen. (milling). In this case, while adjusting the current density of the FIB device sequentially, the predetermined area A including the analysis point 200 may be milled to form each specimen to have a thin width. On the other hand, in order to be able to analyze the specimen by the TEM electrons must pass through the width of the specimen, the milling (milling) each specimen so that the width of the upper surface where the analysis point 200 is located is less than 1000Å desirable. On the other hand, a very long time is required to mill the entire specimen, and only a predetermined area A including the analysis point 200 is required for the TEM analysis. It is preferable to mill only a predetermined area A including, and not to mill the peripheral portion B of the specimen. Therefore, when the specimen is manufactured by the manufacturing method according to the present invention, the predetermined region (A) including the analysis point 200 has a width of 1000 하도록 or less so that analysis by TEM, and the remaining peripheral portion (B) of the specimen Since the width formed in the grinding process, that is, the width of 100 μm or less, the peripheral portion B of the specimen has a much larger width than the predetermined area A including the analysis point 200.

And before performing such a milling process, it is preferable to perform a process of depositing a protective film on a portion including the analysis point 200 of each specimen. Such a protective film may occur on the analysis point 200 located on the upper surface of the specimen when the analysis point 200 of the specimen is observed using a FIB (ion beam focusing) device, or after the micro milling. Minimize damage. On the other hand, a tungsten (W) film, a platinum (Pt) film, a carbon (C) film, an aluminum (Al) film, or the like can be used as the protective film.

And, as shown in Figure 9, the milling (milling) complete the specimen (grid) is attached to the grid (grid) 300. The grid 300 is formed in a disc shape having a diameter of 3 mm, and includes a through hole 310 formed in the center and a donut-shaped support 320 surrounding the through hole 310. And the diameter of the through hole 310 is preferably formed to be less than 2.3mm. In addition, the material of the grid 300 is preferably made of copper (Cu) or nickel (Ni) so as not to affect the carbon analysis on the specimen. For the grid 300 having such a configuration, a predetermined region including the analysis point 200, that is, a milled region A, is positioned on the through hole 310, and the periphery of the analysis point 200. That is, the specimen is attached to the grid 300 so that the non-milled area B of the specimen is supported by the support 320 of the grid 300, so that electrons penetrating the specimen for TEM analysis are gridd. To be unaffected by 300. Meanwhile, by using the grid 300 having a relatively large diameter of the through hole 310, two specimens bonded with epoxy may be attached to the grid 300 at the same time to analyze the two specimens simultaneously. Using the grid 300 having a relatively small diameter of the hole 310, only one of the two bonded specimens may be attached to the grid 300 for analysis.

Although specific embodiments of the present invention have been described with reference to the drawings, this is intended to be easily understood by those skilled in the art and is not intended to limit the technical scope of the present invention. Therefore, the technical scope of the present invention is determined by the matters described in the claims, and the embodiments described with reference to the drawings may be modified or modified as much as possible within the technical spirit and scope of the present invention.

According to the present invention, a grid made of a material that does not contain carbon is used, and electrons emitted from the TEM pass through the specimen and then exit through the grid through holes. The accuracy of carbon analysis can be increased.

In addition, in the present invention, when the specimen is initially separated from the wafer, the size of the specimen is relatively large, so that the specimen is easily separated from the wafer.

In addition, in the present invention, since the two specimens are produced at the same time, it is possible to shorten the process time for the specimen production.

Claims (7)

In the method for preparing a specimen for TEM (transmission electron microscope) analysis, in which two analysis points are to be observed, Dividing the specimen into two specimens so that each analysis point is independently included in the wafer, and cutting each specimen into a predetermined size; Bonding the two cut specimens with epoxy; Grinding each specimen so that a width of the specimen including each analysis point is 100 μm or less; Forming a protective film on a portion of the bonded two specimens including the analysis point; In the bonded two specimens, each specimen is milled with an FIB device (ion beam focusing apparatus) so that the width of the region including the respective analysis points is 1000 Å or less, but the region including the respective analysis points is Milling to be surrounded by a non-milled periphery; Attaching the two bonded specimens to a disc-shaped grid having a through hole formed at a center thereof, wherein an area including each analysis point is located in the through hole, and the periphery is supported by the grid. step; TEM analysis specimen manufacturing method comprising a. delete In claim 1, The protective film is a TEM analysis specimen manufacturing method, characterized in that made of any one of a tungsten (W) film, platinum (Pt) film, carbon (C) film, aluminum (Al) film. In claim 1, The cutting of the test piece is made by a method of forming a groove in each corner of a specific area to be cut, and then applying a shock to separate the test piece of a predetermined size from the wafer. delete In claim 1, The diameter of the grid is 3mm, the diameter of the through hole is a specimen for TEM analysis, characterized in that less than 2.3mm. In claim 1, The grid (grid) is TEM analysis specimen manufacturing method, characterized in that made of copper (Cu) or nickel (Ni) material.

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