Diaphragm structure for focused ion beam system

Abstract

The embodiment of the utility model provides a diaphragm structure for a focused ion beam system, and the diaphragm structure comprises a diaphragm substrate; n rows of diaphragm holes; the diaphragm hole penetrates through the diaphragm base body; n is an integer and is greater than 2; each row of diaphragm holes comprises a plurality of diaphragm holes arranged along a first direction; the N rows of diaphragm holes are sequentially arranged along a second direction; the second direction is intersected with the first direction; wherein the number of the diaphragm holes in the N rows of diaphragm holes is M, and M is greater than 15.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor technology, and more particularly to an aperture structure for a focused ion beam system. Background Technology

[0002] With the miniaturization of semiconductor devices, electron microscopes, such as transmission electron microscopes (TEM), scanning electron microscopes (SEM), focused ion beam microscopes (FIB), and atomic force microscopes (AFM), are needed for the analysis of the microstructure of semiconductor devices. Among them, focused ion beam microscopes accelerate the ion beam generated by ion sources (such as gallium (Ga), helium (He), and neon (Ne) ion sources) with an ion gun and focus it onto the sample surface with an aperture structure. This enables precise micro- and nano-scale cutting, and has advantages such as controllable size and uniform thickness. It is often used for the modification, cutting, and fault analysis of semiconductor devices.

[0003] However, in order to cope with sample preparation and analysis in different scenarios, the lifespan of the aperture structure in the focused ion beam system needs to be extended. Utility Model Content

[0004] In view of this, in order to solve one or more of the existing technical problems, this disclosure proposes an aperture structure for a focused ion beam system, the aperture structure comprising: an aperture substrate; N rows of aperture holes; the aperture holes penetrating the aperture substrate; N being an integer and N > 2; each row of aperture holes including a plurality of aperture holes arranged along a first direction; the N rows of aperture holes being arranged sequentially along a second direction; the second direction intersecting the first direction; wherein, the number of aperture holes in the N rows of aperture holes is M, M > 15.

[0005] In some embodiments, at least some of the apertures in the N rows of apertures have the same aperture diameter.

[0006] In some embodiments, the N rows of apertures include a first aperture and a second aperture; the aperture of the first aperture is smaller than the aperture of the second aperture, and the first aperture is located in the middle region of the N rows of apertures; the second aperture is located in the edge region of the N rows of apertures; the edge region surrounds the middle region.

[0007] In some embodiments, the aperture is circular; the center points of the plurality of apertures arranged along the first direction are located on the same straight line; the extension direction of the straight line is parallel to the first direction.

[0008] In some embodiments, the distance between the center points of two adjacent apertures arranged along the first direction ranges from 0.7 mm to 1.3 mm; and / or, the distance between two adjacent straight lines arranged along the second direction ranges from 0.7 mm to 1.3 mm.

[0009] In some embodiments, the arrangement of the center points of the N rows of apertures includes at least one of triangles, squares, and rectangles.

[0010] In some embodiments, N=3, M=23; wherein, the first row of the three rows of aperture holes includes 8 aperture holes; the second row includes 7 aperture holes; and the third row includes 8 aperture holes.

[0011] In some embodiments, the aperture structure has a rectangular shape with a chamfered angle in the cross-section of the first plane; wherein the chamfered angle is used as a marker position of the aperture structure; the first direction and the second direction intersect to form the first plane.

[0012] In some embodiments, the aperture structure satisfies at least one of the following conditions: the maximum length in the first direction is 20 mm to 25 mm; the maximum width in the second direction is 6 mm to 7 mm; the thickness in the third direction is 0.05 mm to 0.1 mm; and the third direction is perpendicular to both the first and second directions.

[0013] In some embodiments, the material of the aperture substrate includes at least one of molybdenum or carbon.

[0014] In some embodiments, the aperture structure is located between the ion source of the focused ion beam system and the sample placement position, which is used to place the sample to be tested.

[0015] In some embodiments, the sample to be tested includes a 3D NAND flash memory.

[0016] This disclosure provides an aperture structure for a focused ion beam system. The aperture structure includes: an aperture substrate; N rows of aperture holes; the aperture holes penetrating the aperture substrate; N is an integer, and N > 2; each row of aperture holes includes multiple aperture holes arranged along a first direction; the N rows of aperture holes are arranged sequentially along a second direction; the second direction intersects the first direction; wherein the number of aperture holes in the N rows is M, and M > 15. In this disclosure, by setting multiple rows of aperture holes in the aperture structure and making the number of aperture holes greater than 15, the practicality of the aperture structure can be increased, the service life of the aperture structure can be extended, the replacement time of the aperture structure can be reduced, the operating efficiency of the focused ion beam system can be improved, and the operating cost can be reduced. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a focused ion beam system provided in an embodiment of the present disclosure;

[0018] Figure 2 This is a top view of the aperture structure provided in an embodiment of the present disclosure in the XY plane.

[0019] Figure Labels

[0020] 1-Focused ion beam system; 2-Aperture structure; 101-Ion source; 102-Ion extraction electrode; 103-First-stage lens; 104-Aperture structure; 105-Deflector; 106-Second-stage lens; 107-Sample placement position; 108-Sample; 201-Aperture substrate; 202-Aperture aperture.

[0021] In the above figures (which are not necessarily drawn to scale), similar reference numerals may describe similar parts in different views. Similar reference numerals with different letter suffixes may indicate different examples of similar parts. The figures illustrate, by way of example and not limitation, the various embodiments discussed herein. Detailed Implementation

[0022] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0023] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of this disclosure. However, it will be apparent to those skilled in the art that this disclosure may be practiced without one or more of these details. In other instances, to avoid confusion with this disclosure, certain technical features well-known in the art have not been described; that is, not all features of actual embodiments are described herein, nor are well-known functions and structures described in detail.

[0024] In the accompanying drawings, for clarity, the dimensions of layers, areas, and elements, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0025] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this disclosure, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And the discussion of a second element, component, area, layer, or portion does not imply that the first element, component, area, layer, or portion necessarily exists in this disclosure.

[0026] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprise” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0028] To gain a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of this disclosure.

[0029] Figure 1 This is a schematic diagram of a focused ion beam system provided in an embodiment of this disclosure. The focused ion beam system 1 may include an ion source 101, an ion extraction electrode 102, a first-stage lens 103, an aperture structure 104, a deflector 105, a second-stage lens 106, and a sample placement position 107. Gallium is commonly used as the ion source 101 due to its low melting point, low vapor pressure, and good oxidation resistance. The ion extraction electrode 102 can be used to accelerate, pull, and extract the ion beam. The first-stage lens 103 can be used for the initial focusing of the ion beam and to enhance and control the ion transport direction, ensuring that the ion beam leaves the ion source with a preset target direction and energy. The aperture structure 104 can be used to constrain the ion beam and adjust the beam spot size to obtain a usable beam with a preset energy and shape; it can adjust the beam intensity or focus by partially blocking the beam.

[0030] The deflector 105 can be used to control the scanning motion of the ion beam to detect and analyze micro / nano patterns and perform maskless processing on micro / nano structures. The second-stage lens 106 can be used to focus the ion beam a second time to obtain a finer beam. The sample placement position 107 can be used to place the sample 108 to be tested.

[0031] In other words, a focused ion beam system can adjust and focus the ion beam through structures such as lenses, aperture structures, and deflectors, so that the ion beam can act on the surface of the sample under test at high resolution.

[0032] This demonstrates that the aperture structure plays a crucial role in focused ion beam systems, helping to control and manage the intensity and shape of the ion beam, thereby enabling high-precision processing and handling of samples.

[0033] In some specific embodiments, the focused ion beam system is used in a chip cutting machine. With a fixed ion beam current emitted by the ion source, it selects apertures of different aperture sizes (typically circular) in the aperture structure to partially block the ion beam, thereby reducing the intensity of the ion beam passing through the aperture and achieving a preset target ion beam current. For example, if the ion beam current emitted by the ion source is 2 microamps (µA), and the target ion beam current required for the sample surface is 90 picoamperes (pA), then an aperture with a diameter of 40 micrometers (µm) can be selected in the aperture structure and placed between the ion source and the sample. By blocking part of the ion beam through the aperture structure, the ion beam current passing through the aperture is reduced, for example, from 2 µA to 90 pA, thus ensuring that the target ion beam current acting on the sample surface is 90 pA.

[0034] To accommodate different test samples and application scenarios, the apertures of multiple apertures in the aperture structure vary in diameter. However, for the same type of test sample, one or more fixed apertures in the aperture structure need to be used multiple times, resulting in a longer usage time for these fixed apertures. It should be understood that the longer the aperture is used, the longer the ion beam, confined by the aperture structure, bombards the sidewalls of that aperture. This leads to an increase in the aperture diameter of the fixed apertures, rendering them unusable, increasing manufacturing costs, and increasing the time required to replace the aperture structure, thus affecting the operating efficiency of the instrument / focused ion beam system.

[0035] Based on this, in order to solve one or more of the above problems, this disclosure proposes an aperture structure 2 for a focused ion beam system, such as... Figure 2 As shown, the aperture structure 2 includes: an aperture substrate 201; N rows of aperture holes 202; the aperture holes 202 penetrate the aperture substrate 201; N is an integer and N>2; each row of aperture holes includes multiple aperture holes 202 arranged along a first direction; the N rows of aperture holes are arranged sequentially along a second direction; the second direction intersects the first direction; wherein, the number of aperture holes in the N rows of aperture holes is M, M>15.

[0036] In detail Figure 2 Before illustrating the aperture structure, the various directions that may be used in the following description are defined. In this disclosure, the thickness extension direction of the aperture structure is defined as a third direction (Z-axis direction), and intersecting first direction (X-axis direction) and second direction (Y-axis direction) are defined in a plane perpendicular to the Z-axis direction. In some embodiments, the X-axis direction, Y-axis direction, and Z-axis direction may be mutually perpendicular.

[0037] refer to Figure 2The aperture structure 2 has a rectangular cross-sectional shape with a beveled angle in the XY plane. This beveled angle serves as a marker for the aperture structure, allowing for its positioning within the focused ion beam system. The beveled angle can be positioned anywhere on the rectangular aperture substrate. For example,... Figure 2 As shown, the angle α between the oblique line S in the chamfered angle and the X-axis direction can be any angle. Preferably, the angle α is 45° or 135°. The area of ​​the chamfered angle can be set according to actual needs, and this disclosure does not limit it.

[0038] In some embodiments, the aperture structure satisfies at least one of the following conditions: the maximum length in the X-axis direction is 20 mm to 25 mm; the maximum width in the Y-axis direction is 6 mm to 7 mm; and the thickness in the Z-axis direction is 0.05 mm to 0.1 mm.

[0039] refer to Figure 2 The maximum length of the aperture structure in the X-axis direction is L, ranging from 20mm to 25mm. The maximum width of the aperture structure in the Y-axis direction is W, ranging from 6mm to 7mm. The thickness of the aperture structure in the Y-axis direction is H. Figure 2 (Not shown in the figure), H ranges from 0.05 mm to 0.1 mm.

[0040] In this embodiment, the material of the aperture substrate 201 includes at least one of molybdenum (Mo) or carbon (C). In other embodiments, the material of the aperture substrate 201 may also be other materials with high melting points, such as platinum (Pt).

[0041] In this embodiment, the aperture structure can be provided with multiple aperture holes, each of which is circular, and the multiple aperture holes are arranged sequentially in a row or column. It should be noted that the specific arrangement of the multiple aperture holes is related to factors such as the number of aperture holes, the number of rows of aperture holes, the aperture diameter of the aperture holes, and the arrangement of the center points of the aperture holes. The arrangement of the multiple aperture holes will be described in detail below with reference to the embodiments and accompanying drawings.

[0042] In some embodiments, the aperture structure may include M apertures, where M > 15, and the M apertures are distributed in N rows, where N > 2. Each row of apertures may include multiple apertures arranged along the X-axis. The N rows of apertures are arranged sequentially along the Y-axis.

[0043] For example, refer to Figure 2 N=3, M=23; wherein, the first row of the three rows of aperture holes includes eight aperture holes, numbered 1-7 and 15; the second row includes seven aperture holes, numbered 8-14; and the third row includes eight aperture holes, numbered 16-23.

[0044] For example, N=4, M=30; wherein, the first row of the four rows of aperture holes includes 8 aperture holes; the second row includes 7 aperture holes; the third row includes 8 aperture holes; and the fourth row includes 7 aperture holes.

[0045] For example, N=5, M=38; wherein, the first row of the four rows of aperture holes includes eight aperture holes; the second row includes seven aperture holes; the third row includes eight aperture holes; the fourth row includes seven aperture holes; and the fifth row includes eight aperture holes.

[0046] It should be noted that, compared to an aperture structure with fewer than 15 aperture holes, the aperture structure shown in this embodiment has more than 15 aperture holes. Thus, by increasing the number of aperture holes, the service life of the aperture structure can be extended.

[0047] In some embodiments, the center points of multiple apertures in each row are located on the same straight line, and the direction of extension of the line is parallel to the X-axis. This allows the relevant structures in the focused ion beam system to move linearly when changing apertures, reducing the distance of each movement and ensuring more precise positioning or coordinates.

[0048] For example, refer to Figure 2 The center points of the eight apertures numbered 1-7 and 15 in the first row are all located on line r1; the center points of the seven apertures numbered 8-14 in the second row are all located on line r2; and the center points of the eight apertures numbered 16-23 in the third row are all located on line r3. The extension directions of lines r1, r2, and r3 are all parallel to the X-axis direction.

[0049] In some embodiments, the arrangement of the center points of the apertures in the N rows includes at least one of triangles, squares, and rectangles.

[0050] refer to Figure 2 The center points of the multiple apertures in the first row and the multiple apertures in the second row are arranged in a triangle. For example, the center points of apertures numbered 3, 9, and 10 are arranged in a triangle. In this way, multiple apertures in adjacent rows along the Y-axis are spaced apart, increasing the spacing between adjacent apertures, thereby reducing the influence of the ion beam on adjacent apertures. Furthermore, the area of ​​the aperture substrate can be fully utilized, increasing the number of apertures per unit area.

[0051] It should be noted that in other embodiments, the arrangement of the center points of the multiple aperture holes can be in other ways, and this disclosure does not limit it.

[0052] In some embodiments, depending on the application scenario or the requirements of the sample, the apertures of the multiple aperture holes in the aperture structure may be the same or different. In this embodiment of the present disclosure, at least some of the aperture holes in the N rows of aperture holes have the same aperture.

[0053] In some specific embodiments, the number of apertures with the same aperture size in the aperture structure is directly proportional to the duration for which that aperture is used to confine the ion beam. In other words, the more frequently used apertures in the aperture structure have a larger number of apertures with the same aperture size, while the fewer frequently used apertures have a smaller number of apertures with the same aperture size; that is, in actual operation, there are more frequently used apertures and fewer infrequently used apertures. This increases the practicality of the aperture structure, balances the usage time of the apertures, and extends the lifespan of the aperture structure.

[0054] In some embodiments, based on factors such as different aperture diameters and different arrangement of the center points of the apertures, the distance between the center points of two adjacent apertures along the X-axis is in the range of 0.7mm-1.3mm; and / or, the distance between two adjacent straight lines along the Y-axis is in the range of 0.7mm-1.3mm.

[0055] For example, refer to Figure 2 The distance R1 between the center points of two adjacent apertures (such as apertures numbered 4 and 5) along the X-axis is 1.3 mm, and the distance R2 between two adjacent straight lines (such as r1 and r2) along the Y-axis is 1 mm.

[0056] The 23 apertures numbered 1-23 mentioned in the above embodiments are respectively arranged according to... Figure 2 The arrangement of the 23 apertures and the relationship between the ion beam current passing through the corresponding apertures are shown in Table 1.

[0057] Table 1

[0058] serial number Ion beam current serial number Ion beam current 1 1pA 13 0.44pA 2 0.26nA 14 0.75nA 3 7pA 15 65nA 4 26pA 16 1.2nA 5 41pA 17 90pA 6 90pA 18 2.4nA 7 90pA 19 2.4nA 8 0.75nA 20 9.0nA 9 90pA 21 9.0nA 10 90pA 22 20.3nA 11 0.26nA 23 46.6nA 12 1.2nA

[0059] As shown in Table 1, the ion beam current that can pass through apertures numbered 6, 7, 9, 10, and 17 is 90 pA. The ion beam current that can pass through apertures numbered 18 and 19 is 2.4 nA. The ion beam current that can pass through aperture number 1 is 1 pA.

[0060] For example, a 90pA ion beam current is a commonly used ion beam current, and apertures numbered 6, 7, 9, 10, and 17 can all be used to obtain this current. In other words, apertures numbered 6, 7, 9, 10, and 17 are commonly used apertures, meaning there are a relatively large number of commonly used apertures in the aperture structure. Here, the aperture diameters of apertures numbered 6, 7, 9, 10, and 17 can be the same. However, a 1pA ion beam current is a non-common ion beam current, and aperture numbered 1 is a non-common aperture. Therefore, there are fewer apertures in the aperture structure with the same aperture diameter as aperture numbered 1. This arrangement can balance the usage time of apertures with different aperture diameters, extending the lifespan of the aperture structure.

[0061] It should be noted that the ion beam current values ​​shown in Table 1 are fixed values. In other embodiments, the range of ion beam current values ​​that can pass through the same aperture as in Table 1 can fluctuate by 30% above or below the ion beam current values ​​shown in Table 1.

[0062] In some embodiments, the N-row aperture includes a first aperture and a second aperture; the aperture of the first aperture is smaller than the aperture of the second aperture, and the first aperture is located in the middle region of the N-row aperture; the second aperture is located in the edge region of the N-row aperture; the edge region surrounds the middle region.

[0063] It should be understood that the larger the aperture of the aperture, the more ion beams pass through it, i.e., the larger the ion beam current. If a large aperture is placed in the middle region of the aperture structure, the ion beam passing through it may affect the surrounding apertures. However, if a large aperture is placed at the edge of the aperture structure, i.e., other apertures are only placed on one side of the large aperture, the ion beam passing through it will only affect the aperture on that side. This reduces the impact of the ion beam on the surrounding apertures and extends the service life of the aperture structure.

[0064] It should be noted that in some other embodiments, the positions of the multiple aperture holes in the aperture structure can also be set arbitrarily, that is, they are not arranged in a row or column manner; and the aperture diameter of the aperture hole can also be customized according to actual needs, which is not limited in this disclosure.

[0065] In this embodiment of the present disclosure, the aperture structure is located between the ion source of the focused ion beam system and the sample placement position, which is used to place the sample to be tested.

[0066] In some embodiments, the sample to be tested includes a 3D NAND type memory.

[0067] In some embodiments, an aperture can be formed on the aperture substrate by laser drilling.

[0068] Based on this, in this embodiment of the disclosure, by setting multiple rows of aperture holes in the aperture structure and making the number of aperture holes greater than 15, the practicality of the aperture structure can be increased by increasing the number of aperture holes, thereby extending the service life of the aperture structure, reducing the time for replacing the aperture structure, improving the operating efficiency of the focused ion beam system, and reducing operating costs.

[0069] It should be noted that terms such as "first" and "second" are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the technical solutions described in the embodiments of this disclosure can be combined arbitrarily without conflict.

[0070] The above description is merely a preferred embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure.

Claims

1. An aperture structure for a focused ion beam system, characterized in that, The aperture structure includes: Aperture substrate; N rows of aperture holes; the aperture holes penetrate the aperture substrate; N is an integer and N>2; each row of aperture holes includes multiple aperture holes arranged along a first direction; the N rows of aperture holes are arranged sequentially along a second direction; the second direction intersects the first direction; Among them, the number of apertures in the N rows is M, where M>15.

2. The aperture structure according to claim 1, characterized in that, At least some of the apertures in the N rows have the same aperture diameter.

3. The aperture structure according to claim 1, characterized in that, The N rows of apertures include a first aperture and a second aperture; the diameter of the first aperture is smaller than the diameter of the second aperture, and the first aperture is located in the middle region of the N rows of apertures; the second aperture is located in the edge region of the N rows of apertures; the edge region surrounds the middle region.

4. The aperture structure according to claim 1, characterized in that, The aperture is circular; the center points of the plurality of apertures arranged along the first direction are located on the same straight line; the extension direction of the straight line is parallel to the first direction.

5. The aperture structure according to claim 4, characterized in that, The distance between the center points of two adjacent apertures arranged along the first direction ranges from 0.7 mm to 1.3 mm; and / or, The distance between two adjacent straight lines arranged along the second direction ranges from 0.7 mm to 1.3 mm.

6. The aperture structure according to claim 5, characterized in that, The arrangement of the center points of the N rows of apertures includes at least one of triangles, squares, and rectangles.

7. The aperture structure according to claim 6, characterized in that, N=3, M=23; where the first row of the three rows of aperture holes includes 8 aperture holes; the second row includes 7 aperture holes; and the third row includes 8 aperture holes.

8. The aperture structure according to claim 1, characterized in that, The aperture structure has a rectangular shape with a beveled angle in its cross-section on the first plane; The oblique angle is used as a marker position for the aperture structure; the first direction and the second direction intersect to form the first plane.

9. The aperture structure according to claim 8, characterized in that, The aperture structure satisfies at least one of the following conditions: The maximum length in the first direction is between 20 mm and 25 mm; The maximum width range in the second direction is 6 mm to 7 mm; The thickness ranges from 0.05 mm to 0.1 mm on the third-party side; The third direction is perpendicular to both the first direction and the second direction.

10. The aperture structure according to claim 1, characterized in that, The material of the aperture substrate includes at least one of molybdenum or carbon.

11. The aperture structure according to claim 1, characterized in that, The aperture structure is located between the ion source of the focused ion beam system and the sample placement position, which is used to place the sample to be tested.

12. The aperture structure according to claim 11, characterized in that, The sample to be tested includes a 3DNAND type memory.

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