FIB sample holder of rotatable network carrying table and use method of FIB sample holder

Abstract

The invention discloses an FIB sample seat of a rotatable net carrying table, which comprises a base and a net carrying support, and the base is provided with a nail table hole and a groove; the net carrying support is located at the front end of the groove, and a rotary button is arranged at the top of the groove. The groove and the grid carrying support are used for fixing the grid carrying table, the grid carrying support rotates to drive the grid carrying table to rotate, and the grid carrying table and a sample can be switched from a horizontal state to a vertical state, so that FIB reverse cutting operation can be carried out under one-time sample injection, the operation of breaking vacuum and changing samples in conventional FIB reverse cutting is reduced, the FIB reverse cutting step is simplified, and the FIB reverse cutting efficiency is improved. The TEM sample preparation time is shortened, and the sample preparation cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor chip manufacturing, and in particular relates to a FIB sample holder of a rotatable grid stage and a use method thereof. Background Art

[0002] Transmission Electron Microscope (TEM) is widely used in semiconductor chip analysis due to its nanometer-level resolution. However, TEM testing has high sample thickness requirements. Focused Ion Beam (FIB) is often used to prepare TEM samples due to its high precision. With the gradual development of semiconductor chip technology, the size of device structures has also decreased, which means that the requirements for TEM sample preparation are getting higher and higher, and thinner TEM samples need to be prepared. At this time, traditional FIB tangents can no longer meet the requirements, and FIB reverse cutting is needed to prepare thinner areas of interest.

[0003] Using FIB inverted cutting to prepare TEM samples can obtain thinner areas of interest. When preparing samples by FIB inverted cutting, the grid needs to be changed from horizontal to vertical. However, since the sample stage of the existing 52° FIB equipment can rotate from about -10° to 56°, it is impossible to meet the requirements in one injection. At this time, it is necessary to break the vacuum to take the sample, change the grid from horizontal to vertical, and then re-evacuate, which greatly wastes the time of preparing TEM samples. Frequent vacuuming will also reduce the life of the equipment. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a FIB sample holder with a rotatable grid stage and a use method thereof, which can improve the efficiency of inverted FIB sample preparation.

[0005] In order to achieve the above-mentioned object, the present invention provides a FIB sample holder with a rotatable grid stage, comprising a base and a grid holder, wherein the base is provided with a nail stage hole and a groove.

[0006] Preferably, the net support is located at the front end of the groove, and a rotation button is provided at the top of the groove.

[0007] Preferably, the top of the groove is provided with nail platform holes, and the number of the nail platform holes is 1-3.

[0008] Furthermore, the rotating button is connected to the first spring, the first spring is connected to the first limiter and the second spring, and the second spring is connected to the net support.

[0009] More preferably, the first limiter is linked to the second limiter; and a baffle is provided at one end of the second spring.

[0010] Preferably, the base is 2-4 cm long, 1-3 cm wide and 1-2 cm high.

[0011] Preferably, the net support has a length of 4-7 mm, a width of 1-2 mm, and a thickness of 1-2 mm.

[0012] The present invention also provides a method for using a FIB sample holder of a rotatable grid stage, comprising the following steps: (1) Load the sample on the grid stage, then load the grid stage on the grid support, and keep the grid support and the base level; (2) placing the FIB sample holder containing the sample and the grid in the FIB sample chamber, with the grid parallel to the sample and the grid perpendicular to the electron beam; (3) Adjust the ion beam perpendicular to the sample and adjust it to the first parameter to dig out the area of ​​interest in the sample; (4) adjusting the electron beam perpendicular to the sample and extracting the region of interest using a nanomanipulator; (5) Make the copper pillar in the carrier grid face right, and use a tungsten needle to plate tungsten to weld the area of ​​interest on its side; (6) Use the nanomanipulator to touch the rotation button, and the grid holder rotates 90° to drive the sample perpendicular to the base; (7) adjusting the ion beam to be perpendicular to the sample, where the region of interest is below the sample and the material substrate is above the sample; (8) A tungsten protective layer is deposited on the substrate surface above the sample, and then the ion beam is adjusted to the second parameter to start FIB undercutting and thinning; (9) Repeat the thinning operation in step (8) until the sample thickness required for the experiment is achieved.

[0013] Preferably, the first parameter in step (3) is an acceleration voltage of 5-30 kV and a beam current of 9.3-47 nA.

[0014] Preferably, the second parameter in step (8) is an acceleration voltage of 5-30 kV and a beam current of 0.23-2.5 nA.

[0015] The beneficial effects of the present invention are: 1. The present invention can control the angle of the grid holder by rotating the button and the internal spring and limit structure, so that the grid stage can be rotated and switched between the horizontal state and the vertical state, which is convenient for FIB inverted cutting, reduces the operation of breaking the vacuum and changing the sample in the conventional FIB inverted cutting, simplifies the FIB inverted cutting steps, reduces the TEM sample preparation time, and saves the sample preparation cost.

[0016] 2. The present invention has a simple structure and a simple method of use, improves the efficiency of preparing FIB samples, prolongs the service life of the equipment, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the overall structure diagram of the present invention.

[0018] Figure 2 It is a schematic diagram of the overall structure when the net support is in a horizontal state.

[0019] Figure 3 This is a schematic diagram of the internal connections of the rotation button when the web support is in a horizontal position.

[0020] Figure 4 This is a schematic diagram of the internal connections of the rotation button when the web support is in a vertical position.

[0021] Figure 5 This is a schematic diagram of the structure of the network loading station in Example 2.

[0022] Figure 6 It is a cross-sectional view of the network loading platform in Example 2.

[0023] In the figure, 1 is a base, 2 is a nail stand hole, 3 is a groove, 4 is a net holder, 5 is a rotation button, 6 is a first spring, 7 is a first limiter, 8 is a second limiter, 9 is a baffle, 10 is a second spring, and 11 is a slot for the net holder. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be understood as limiting the present invention. The protection scope of the present invention shall be based on the contents recorded in the claims. Any modification or replacement made by those skilled in the art to the technical solution of the present invention without creative work shall fall within the protection scope of the present invention.

[0025] Example 1 like Figure 1-4 As shown, a FIB sample holder with a rotatable grid stage comprises a base 1 and a grid holder 4, wherein the base 1 is provided with a nail stage hole 2 and a groove 3.

[0026] Preferably, the net support 4 is located at the front end of the groove 3, and a rotation button 5 is provided at the top of the groove.

[0027] Preferably, a nail platform hole 2 is provided at the top of the groove 3, and the number of the nail platform holes 2 is 1-3.

[0028] More preferably, the number of the nail platform hole 2 is one.

[0029] Further, the rotating button 5 is connected to the first spring 6, the first spring 6 is connected to the first limiter 7 and the second spring 10, and the second spring 10 is connected to the net support 4; when the angle of the net support 4 is 90° (perpendicular to the base 1), the rotating button 5 is in a concave state, at this time the first spring 6 is compressed, the second spring 10 pops out from the gap between the first limiter 7 and the second limiter 8 and is blocked by the baffle 9; when the angle of the net support 4 is 0° (parallel to the base 1), the rotating button 5 is in a protruding state, at this time the second spring 10 is compressed and limited by the first limiter 7 and the second limiter 8, and the first spring 6 is relaxed, so that the rotating button 5 remains in a protruding state.

[0030] More preferably, the first limiter 7 is linked with the second limiter 8 ; and a baffle 9 is provided at one end of the second spring 10 .

[0031] Preferably, the base 1 is 2-4 cm long, 1-3 cm wide and 1-2 cm high.

[0032] Further preferably, the base 1 is 3 cm long, 2 cm wide and 1 cm high.

[0033] Preferably, the web support 4 has a length of 4-7 mm, a width of 1-2 mm, and a thickness of 1-2 mm.

[0034] Further preferably, the net support 4 has a length of 6 mm, a width of 1 mm, and a thickness of 1 mm.

[0035] Further preferably, the grid holder 4 is used to hold the grid stage to assist in fixing the grid. Before the grid is loaded into the grid stage, the angle of the grid holder 4 is 90°, that is, perpendicular to the base 1; after the grid is loaded into the grid stage, the angle of the grid holder 4 will become 0°, that is, parallel to the base 1, which is convenient for the ion beam to cut and dig out the area of ​​interest in the sample.

[0036] Example 2 A method for using a FIB sample holder of a rotatable grid stage comprises the following steps: (1) Manually load the sample onto the grid stage, then use the grid holder slot 11 in the grid stage to load the grid stage onto the grid holder 4, and adjust the angle of the grid holder 4 to 0°, that is, the grid holder 4 is kept horizontal with the base 1, to obtain a FIB sample holder with the sample and grid; (2) placing the FIB sample holder containing the sample and the grid in the FIB sample chamber, with the grid parallel to the sample and the grid and the sample perpendicular to the electron beam; (3) Adjust the ion beam perpendicular to the sample and adjust it to the first parameter to dig out the area of ​​interest in the sample; (4) adjusting the electron beam perpendicular to the sample and extracting the region of interest using a nanomanipulator; (5) Make the copper pillar in the carrier grid face right, and use a tungsten needle to plate tungsten to weld the area of ​​interest on its side; (6) Using the nanomanipulator to touch the rotation button 5, the rotation button 5 changes from a protruding state to a concave state, thereby rotating the network support 4 by 90° and driving the sample to be perpendicular to the base 1; (7) adjusting the ion beam to be perpendicular to the sample, where the region of interest is below the sample and the material substrate is above the sample; (8) A tungsten protective layer is deposited on the substrate surface above the sample, and then the ion beam is adjusted to the second parameter to start FIB undercutting and thinning; (9) Repeat the thinning operation in step (8) until the sample thickness required for the experiment is achieved.

[0037] Preferably, the first parameters in step (3) are an acceleration voltage of 30 kV and a beam current of 9.3 nA.

[0038] Preferably, the second parameter in step (8) is an acceleration voltage of 30 kV and a beam current of 0.23 nA.

Claims

1. A FIB sample holder with a rotatable grid stage, characterized in that: It comprises a base (1) and a net carrier (4), wherein the base (1) is provided with a nailing hole (2) and a groove (3).

2. The FIB sample holder of a rotatable grid stage according to claim 1, characterized in that: The web carrier (4) is located at the front end of the groove (3), and a rotation button (5) is provided at the top of the groove.

3. The FIB sample holder of a rotatable grid stage according to claim 1, characterized in that: The top of the groove (3) is provided with nail base holes (2), and the number of the nail base holes (2) is 1 to 3.

4. The FIB sample holder of a rotatable grid stage according to claim 2, characterized in that: The rotating button (5) is connected to the first spring (6), the first spring (6) is connected to the first limiter (7) and the second spring (10), and the second spring (10) is connected to the net support (4).

5. The FIB sample holder of a rotatable grid stage according to claim 4, characterized in that: The first stopper (7) is linked to the second stopper (8); a baffle (9) is provided at one end of the second spring (10).

6. The FIB sample holder of a rotatable grid stage according to claim 1, characterized in that: The base (1) has a length of 2-4 cm, a width of 1-3 cm, and a height of 1-2 cm.

7. The FIB sample holder of a rotatable grid stage according to claim 1, characterized in that: The web support (4) has a length of 4-7 mm, a width of 1-2 mm, and a thickness of 1-2 mm.

8. A method for using the FIB sample holder of the rotatable grid stage according to any one of claims 1 to 7, characterized in that: The steps include: (1) Load the sample onto the grid stage, then load the grid stage onto the grid support (4), and keep the grid support (4) and the base (1) level; (2) placing the FIB sample holder containing the sample and the grid in the FIB sample chamber, with the grid parallel to the sample and the grid perpendicular to the electron beam; (3) Adjust the ion beam perpendicular to the sample and adjust it to the first parameter to dig out the area of ​​interest in the sample; (4) adjusting the electron beam perpendicular to the sample and extracting the region of interest using a nanomanipulator; (5) Make the copper pillar in the carrier grid face right, and use a tungsten needle to plate tungsten to weld the area of ​​interest on its side; (6) Using the nanomanipulator to touch the rotation button (5), the mesh support (4) rotates 90° to move the sample perpendicular to the base (1); (7) adjusting the ion beam to be perpendicular to the sample, where the region of interest is below the sample and the material substrate is above the sample; (8) A tungsten protective layer is deposited on the substrate surface above the sample, and then the ion beam is adjusted to the second parameter to start FIB undercutting and thinning; (9) Repeat the thinning operation in step (8) until the sample thickness required for the experiment is achieved.

9. The method of use according to claim 8, characterized in that: The first parameters described in step (3) are an acceleration voltage of 5-30 kV and a beam current of 9.3-47 nA.

10. The method of use according to claim 8, characterized in that: The second parameters described in step (8) are an acceleration voltage of 5-30 kV and a beam current of 0.23-2.5 nA.

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