A Device for Extracting and Placing a Lamella

Abstract

A device for creating and placing a lamella comprises a focused ion beam, a scanning electron microscope, a stage for placing at least two specimens enabling tilting, rotation and movement of the specimen. The device further comprises a manipulator terminated by a needle for attaching and transporting the specimen. The manipulator is positioned in a plane perpendicular to the axis of the tilt of the specimen, thereby enabling easy transportation and placing of the lamella into the specimen holder for a transmission electron microscope, so-called grid. The manipulator is adjusted to rotate the needle about its own axis. Thus, it enables inverting of the lamella and its polishing over a layer of semiconductor substrate, on which a semiconductor structure is formed, in case of creating the lamella from a semiconductor device.

Claims

1. A device for extracting and placing a lamella, comprising a focused ion beam column, a scanning electron microscope column, and a specimen chamber with a stage for positioning of at least two specimens enabling tilting, rotation and movement along three mutually perpendicular axes, wherein the tilting is enabled about the axis perpendicular to a plane defined by the axis of the focused ion beam column and by the axis of the scanning electron microscope column, and the rotation is enabled about the vertical axis, further comprising a handler terminated by a needle, which is able to move and rotate about its own axis, wherein the handler is positioned in a plane defined by the axis of the focused ion beam column and by the axis of the scanning electron microscope column, wherein the handler is placed directly under the focused ion beam column and above an intersection of the axis of the scanning electron microscope column and the axis of the focused ion beam column.

2. The device for extracting and placing a lamella according to claim 1, wherein the handler is placed at an angle 0-35 from the line perpendicular to the axis of the scanning electron microscope column and intersecting the intersection of the axis of the scanning electron microscope column and the axis of the focused ion beam column, wherein the intersection is the vertex of the angle.

3. The device for extracting and placing a lamella according to claim 1, wherein the handler is positioned closer to the focused ion beam column.

4. The device for extracting and placing a lamella according to claim 1, wherein the stage is adjusted for placing the specimens about the axis of the rotation.

5. The device for extracting and placing a lamella according to claim 1, wherein it further comprises a gas admission system.

6. A method for extracting and placing a lamella comprising the steps of tilting the specimen to the first position, wherein in the first position the surface of the specimen is perpendicular to the focused ion beam column; sputtering the sides of the future lamella by the focused ion beam column; tilting the specimen to the second position; cutting the edges of the lamella by the focused ion beam column; attaching the lamella to the needle of the handler and placing the lamella in the grid wherein the needle approaches the lamella perpendicularly to the surface of the lamella.

7. The method for extracting and placing the lamella according to the claim 6 wherein upon extracting the lamella from the specimen, the handler is rotated by 180 and the lamella is polished by the focused ion beam column.

Description

DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows a device for processing and examining the specimen according to the invention.

[0020] FIGS. 2-7 show a procedure of extracting and placing the specimen in the device according to the invention.

EXEMPLARY EMBODIMENTS OF THE INVENTION

[0021] FIG. 1 illustrates a device according to the present invention. On the specimen chamber 1, a scanning electron microscope column 2 is positioned, comprising an electron source 21, an SEM condenser 22, an SEM aperture 23, an SEM objective 24, and SEM scanning coils 25. Further, a focused ion beam column 3 is positioned on the specimen chamber 1 comprising an ion source 31, an FIB extractor 32, an FIB objective lens 33 and an FIB scanning system 34. A stage 4 is positioned in the specimen chamber 1, which enables a gradient of the perpendicular axis to the plane defined by the axis of the focused ion beam column 3 and the axis of the scanning electron microscope column 2, a rotation about the axis which is vertical with zero tilt, and a movement in three mutually perpendicular axes. The device further comprises a handler 5 terminated by a needle 6 that is able to move and rotate about its own axis. The handler 5 is positioned in a plane defined by the axis of the focused ion beam column 3 and the axis of the scanning electron microscope column 2. The handler 5 is positioned closer to the focused ion beam column 3.

[0022] The device can be used for example to extract and place a lamella 11 from a semiconductor specimen. A specimen 8 and a grid 9 for placing the lamella 11 are positioned on the stage 4, as shown in FIG. 2. The structure of the semiconductor specimen 8 consists of metal layers and of dielectric layers, which are placed on the layer of a semiconductor substrate, usually silicon. The grid 9 is of a semi-circular shape with projections on which lamellae 11 are positioned. The grid 9 is positioned on the stage 4 vertically, perpendicularly to the plane defined by the axis of the focused ion beam column 3 and the axis of the scanning electron microscope column 2.

[0023] As shown in FIG. 3, the stage 4 is tilted about the axis of the gradient to the focused ion beam column 3 so that the surface of the specimen 8 is perpendicular to the axis of the focused ion beam column 3. In this position, the material of the specimen 8 is sputtered so that two opposite cross-sections of the specimen 8 are sputtered, thereby creating the lamella 11. With this sputtering, it is possible to admit appropriate gas by the gas admission system 10 depending on the exact composition of the specimen 8, for example to accelerate the sputtering or to reduce the curtaining effect. It is possible to monitor the sputtering using the scanning electron microscope or the focused ion beam.

[0024] The stage 4 is then tilted into the second position, where the lamella 11 is cut out around the perimeter by ion beam 12 and stays fixed only to a small portion of the specimen 8. As shown in FIG. 4, the stage 4 is tilted so that the needle 6 could proximate to the surface of the lamella 11 perpendicularly. In this position, the needle 6 is fixed to the lamella 11 by a deposition of appropriate material, supplied by the gas admission system 10, using the electron beam or the ion beam 12 or otherwise. The lamella 11 is then released by the ion beam 12 from the specimen 8 and the lamella is raised from the specimen 8 by the handler 5, as shown in FIG. 5. The handler 5 rotates the needle 6 by 180, thereby converting the lamella 11 (FIG. 6).

[0025] As shown in FIG. 7, the lamella 11 in this inverted position is moved by the handler 5 and placed in the grid 9. The lamella 11 can be further polished in the grid 9 using the ion beam 12 preferably from the side of the semiconductor substrate, which prevents the formation of curtaining effect. For polishing and examining the lamella 11 from different sides, it is then possible to use tilting, rotation or movement of the stage 4. During the whole preparation of the lamella 11, the operation can be observed using the scanning electron microscope.

[0026] The lamella 11 placed in the grid 9 can be further transported into TEM for further examination.

LIST OF REFERENCE SIGNS

[0027] 1specimen chamber

[0028] 2scanning electron microscope column

[0029] 3focused ion beam column

[0030] 4stage

[0031] 5handler

[0032] 6needle

[0033] 8specimen

[0034] 9grid

[0035] 10gas admission system

[0036] 11lamella

[0037] 12ion beam

[0038] 21electron source

[0039] 22SEM condenser

[0040] 23SEM aperture

[0041] 24SEM objective

[0042] 25SEM scanning coils

[0043] 31ion source

[0044] 32FIB extractor

[0045] 33FIB objective lens

[0046] 34FIB scanning system