Method and system for leakage location of semiconductor structure

Abstract

The present application provides a method and a system for locating leakage current in a semiconductor structure. The semiconductor structure includes a semiconductor layer, a metal layer, and a plurality of contact portions penetrating the semiconductor layer along a first direction. Among them, the contact portion includes a conductive layer and an insulating layer, the insulating layer surrounds the conductive layer along the first direction, and the conductive layers are electrically connected via the metal layer. The method is characterized in that it includes: extracting an initial sample including a leakage contact portion from the semiconductor structure, wherein the conductive layer in the leakage contact portion is electrically connected to the semiconductor layer; removing the metal layer in the initial sample to obtain a detection sample, wherein the semiconductor layer in the detection sample is grounded; and detecting the contact portions in the detection sample and locating the leakage contact portion based on the detection result.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and more particularly, to a method and system for leakage location of a semiconductor structure. Background Art

[0002] In the current analysis of the failure causes of semiconductor structures (including 3D NAND), it is necessary to locate the position where the failure occurs. The existing analysis methods usually use Thermal EMMI (Emission Microscope) and Laser OBIRCH (Optical Beam Induced Resistance Change) to capture hotspots for locating the failure position, and the PVC (Passive voltage contrast) contrast analysis technology is used to refine the location of the failure structure.

[0003] PVC is a powerful location tool in semiconductor failure analysis, which can be realized by FIB (Focused Ionbeam) or SEM (Scanning Electronic Microscopy). The principle of PVC is to display any position with abnormal charge through a secondary electron image. For semiconductor devices, in most cases, the PVC ion beam will positively charge the sample surface, causing the secondary electrons on the surface to escape. All metal structures with a grounding path become brighter, while the floating metal structures become relatively darker. Any difference in voltage contrast can indicate an abnormality in the metal and its connections.

[0004] It should be understood that the content described in this background art section is only used to help understand the technical solution disclosed in the present application, and does not necessarily belong to the prior art before the filing date of the present application. Summary of the Invention

[0005] On the one hand, the present application provides a method for leakage location of a semiconductor structure. The semiconductor structure includes a semiconductor layer, a metal layer, and a plurality of contact parts penetrating the semiconductor layer along a first direction. Wherein, the contact part includes a conductive layer and an insulating layer, the insulating layer surrounds the conductive layer along the first direction, and the conductive layers are electrically connected through the metal layer. The method is characterized in that it includes: extracting an initial sample including a leakage contact part from the semiconductor structure, wherein the conductive layer in the leakage contact part is electrically connected to the semiconductor layer; removing the metal layer in the initial sample to obtain a detection sample, wherein the semiconductor layer in the detection sample is grounded; and detecting the contact parts in the detection sample and locating the leakage contact part based on the detection result.

[0006] In one embodiment, the step of removing the metal layer from the initial sample includes thinning the initial sample along the first direction and / or the opposite direction of the first direction to remove the metal layer, wherein opposite sides of the contact portion in the thinned initial sample are completely exposed.

[0007] In one embodiment, the steps of detecting the contact portion in the test sample and locating the leakage contact portion include irradiating the test sample with at least one of an ion beam emitted by a focused ion beam or an electron beam emitted by a scanning electron microscope; obtaining a voltage contrast image of the contact portion in the test sample; and locating the leakage contact portion in the voltage contrast image using passive voltage contrast.

[0008] In one embodiment, the step of extracting the initial sample includes capturing a hot spot of the semiconductor structure by at least one of a photoemission method and a photoresistive method, wherein the leakage contact portion is located within the hot spot; marking the hot spot; and cutting out the initial sample based on the marking.

[0009] In one embodiment, the step of removing the metal layer from the initial sample to obtain the test sample includes transferring the initial sample to a sample stage, wherein the semiconductor layer of the initial sample is connected to the sample stage and the sample stage is grounded; and removing the metal layer from the initial sample to form the test sample grounded via the sample stage.

[0010] In one embodiment, the sample stage includes a sample-carrying metal mesh, and the semiconductor layer of the initial sample is located on the sample-carrying metal mesh and grounded via the sample-carrying metal mesh.

[0011] In one embodiment, the semiconductor structure is cut by a focused ion beam cutting method to obtain the initial sample.

[0012] In one embodiment, the size of the hot spot in a direction perpendicular to the first direction is 1 μm - 20 μm.

[0013] In one embodiment, the acceleration voltage of the focused ion beam is 1 kV - 30 kV.

[0014] In one embodiment, the semiconductor structure is a 3D NAND memory.

[0015] On the other hand, the present application provides a leakage location system, which is characterized by including: a sample thinning device configured to thin at least a part of an initial sample along a first direction and / or the opposite direction of the first direction to obtain a test sample; and a sample stage configured to ground at least a part of the test sample.

[0016] In one embodiment, the system further includes: a detection module configured to perform voltage detection on the detection sample by at least one of an ion beam emitted by a focused ion beam or an electron beam emitted by a scanning electron microscope; an analysis and display module configured to record and output a voltage contrast image of the detection sample; and a positioning module configured to locate a leakage position in the sample through a contrast difference in the voltage contrast image.

[0017] In one embodiment, the initial sample includes a semiconductor layer, a leakage contact portion, and a metal layer. The leakage contact portion penetrates the semiconductor layer along the first direction and includes a conductive layer and an insulating layer. The insulating layer surrounds a part of the conductive layer along the first direction, and a part of the conductive layer not surrounded by the insulating layer is in contact with the semiconductor layer. The conductive layer is electrically connected via the metal layer. The sample thinning device is configured to remove the metal layer along the first direction and / or the opposite direction of the first direction, and the sample stage is configured to ground the semiconductor layer.

[0018] The semiconductor structure leakage location method provided by this application may have at least one of the following beneficial effects:

[0019] According to some embodiments of this application, the position of the leakage contact portion can be accurately located, greatly increasing the success rate of failure analysis of the semiconductor structure.

[0020] According to some embodiments of this application, after accurately locating the leakage contact portion, only a single contact portion needs to be subjected to failure analysis, greatly reducing the time cost and machine cost, thereby improving the analysis efficiency and reducing the expenditure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In conjunction with the drawings, through the following detailed description of non-limiting embodiments, other features, objects, and advantages of this application will become more apparent. In the drawings:

[0022] Figure 1 is a schematic diagram of a contact portion in a semiconductor structure according to some embodiments;

[0023] Figure 2 is a schematic diagram of a hot spot captured in a semiconductor structure according to some embodiments;

[0024] Figure 3 is a flowchart of a semiconductor structure leakage location method according to an exemplary embodiment of this application;

[0025] Figure 4 is a schematic diagram of a local structure in a semiconductor structure according to an exemplary embodiment of this application;

[0026] Figure 5 is a schematic diagram of a chip having a semiconductor structure according to an embodiment of the present application;

[0027] Figure 6 is a schematic diagram of forming an initial sample in a method for locating leakage current in a semiconductor structure according to an embodiment of the present application;

[0028] Figure 7 is a schematic diagram of transferring the initial sample to a sample stage in a method for locating leakage current in a semiconductor structure according to an embodiment of the present application;

[0029] FIG. 8 is a schematic diagram of preparing a test sample in a method for locating leakage current in a semiconductor structure according to an embodiment of the present application;

[0030] Figure 9 is a schematic diagram of locating a leakage contact portion in a method for locating leakage current in a semiconductor structure according to an exemplary embodiment of the present application;

[0031] FIG. 10 is a scanning electron microscope image of precisely locating a leakage contact portion by a leakage current location method according to an embodiment of the present application; and

[0032] Figure 11 is a schematic diagram of a leakage current location system according to an exemplary embodiment of the present application. Detailed Embodiments

[0033] To better understand the present application, more detailed descriptions of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another feature and do not represent any limitation on the feature, especially not any order. Therefore, without departing from the teachings of the present application, the first direction discussed in the present application can also be referred to as the second direction, and vice versa.

[0035] In the specification, the references to "one embodiment", "an embodiment", "exemplary embodiment", "some embodiments", etc. indicate that the described embodiments may include specific features, structures, or characteristics, but each embodiment may not necessarily include the specific feature, structure, or characteristic. In addition, these phrases do not necessarily refer to the same embodiment. Further, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in connection with other embodiments will be within the knowledge of those skilled in the relevant art whether or not explicitly described.

[0036] In the accompanying drawings, for ease of illustration, the thickness, dimensions, and shapes of the components have been slightly adjusted. The drawings are provided by way of example and are not drawn to an exact scale. For example, in the present application, the thickness of the semiconductor layer drawn in the drawings is not in proportion to that in actual production. As used herein, terms such as "substantially", "about", and similar terms are used as terms indicating approximation, rather than terms indicating degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by a person of ordinary skill in the art.

[0037] It should be understood that expressions such as "comprising", "including", "having", "containing", and / or "including having" in this specification are open-ended rather than closed-ended expressions, which mean that there are the stated features, elements, and / or components, but do not exclude the presence of one or more other features, elements, components, and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of features, rather than just an individual element in the list. In addition, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to refer to an example or illustration.

[0038] It should also be understood that the meanings of "on", "above", and "over" in the present disclosure should be interpreted in the broadest manner, such that "on" not only means "directly on something", but also includes the meaning of "on something" with intermediate features or layers therebetween, and "above" or "over" not only means the meaning of "above" or "over" something, but may also include the meaning of "above" or "over" something with no intermediate features or layers therebetween (i.e., directly on something).

[0039] Unless otherwise defined, all terms used herein (including engineering terms and technical terms) have the same meaning as commonly understood by a person of ordinary skill in the art to which this application belongs. It should also be understood that, unless clearly stated in this application, words defined in a common dictionary should be interpreted as having a meaning consistent with their meaning in the context of the related art, and should not be interpreted in an idealized or overly formal sense.

[0040] It should be noted that, without conflict, the embodiments and features in the embodiments of this application may be combined with each other. In addition, unless clearly defined or in conflict with the context, the specific steps included in the methods described in this application do not have to be limited to the recited order, but may be executed in any order or executed in parallel. The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0041] The features, principles, and other aspects of the present application are described in detail below.

[0042] The inventors of the present application have found that in a semiconductor structure, there is a contact portion with a special structure. This contact portion separates the conductive layer from the conductive substrate outside it by wrapping an insulating material on the surface of the conductive layer. In some embodiments, there may be defects such as voids in the insulating layer formed around the conductive layer; in addition, the pressure difference between the conductive layer and the conductive column connected thereto may also cause rupture defects in the insulating layer. When the void defects and rupture defects are severe, they may cause abnormal leakage in the conductive contact portion of the semiconductor structure. In failure location technology, the failure location is usually determined by capturing hot spots, but there are some drawbacks in the application of this location method to the above contact portion.

[0043] For example Figure 1 As shown, due to the large number of repetitively interconnected contact portions in the semiconductor structure, the failure location cannot be directly determined by passive voltage contrast; when defect location is performed by capturing hot spots, even if a relatively convergent hot spot area is obtained, the range that the operator needs to observe includes dozens of contact portions, and precise location cannot be performed (as Figure 2 shown); in addition, finding the leakage location by using FIB and SEM machines greatly increases the time cost and machine cost of failure analysis.

[0044] The present application proposes a method for locating leakage in a semiconductor structure, which can at least partially improve or solve the above problems. The position of the leakage contact portion can be accurately located, greatly increasing the success rate of failure analysis of the semiconductor structure. After accurately locating the leakage contact portion, only a single contact portion needs to be subjected to failure analysis, greatly reducing the time cost and machine cost, thereby improving the analysis efficiency and reducing the cost.

[0045] Figure 3 is a flowchart of a method 1000 for locating leakage in a semiconductor structure according to an embodiment of the present application. As Figure 3 shown, the present application provides a method 1000 for locating leakage in a semiconductor structure, including:

[0046] Step S1100, extracting an initial sample including a leakage contact portion from the semiconductor structure, wherein the conductive layer in the leakage contact portion is electrically connected to the semiconductor layer;

[0047] Step S1200, removing the metal layer in the initial sample to obtain a detection sample, wherein the semiconductor layer in the detection sample is grounded; and

[0048] Step S1300, detecting the contact portion in the detection sample and locating the leakage contact portion based on the detection result.

[0049] It should be understood that the steps shown in method 1000 are not exclusive, and other steps may be performed before, after, or between any of the shown steps. In addition, some of the shown steps may be performed simultaneously or may be performed in an order different from Figure 3 that shown.

[0050] Figures 5 to 9 is a process schematic diagram of the leakage location method 1000 for a semiconductor structure according to an embodiment of the present application. The above steps S1100 to S1300 will be further described below in conjunction with Figures 5 to 9 this.

[0051] Step S1100, extract an initial sample including a leakage contact part from a semiconductor structure, wherein the conductive layer in the leakage contact part is electrically connected to the semiconductor layer. The conductive layer in the leakage contact part is electrically connected to the semiconductor layer.

[0052] Figure 4 is a schematic diagram of the local structure 100 in a semiconductor structure according to an embodiment of the present application. As Figure 4 shown, the local structure 100 may include a semiconductor layer 110, a contact portion 121, and a metal layer, and the metal layer may include a first metal layer 130, a second metal layer 140, or a combination of the first metal layer 130 and the second metal layer 140. The contact portion 121 penetrates the semiconductor layer 110 along a first direction (opposite to the z direction). The contact portion 121 may include a conductive layer 123 and an insulating layer 122, and the insulating layer 122 surrounds the conductive layer 123 in the z-axis direction. The conductive layer 123 is connected to the first metal layer 140, so that a plurality of contact portions 121 are electrically connected to each other in an electric field. It should be noted that the semiconductor structure in the embodiment of the present application includes a 3D NAND memory.

[0053] In some embodiments, the local structure 100 further includes a dielectric layer 150, and the contact portion 121 further includes a conductive pillar 160. The first metal layer 130 is located on the upper side (along the z direction) of the semiconductor layer 110, and the dielectric layer 150 and the second metal layer 140 are arranged in sequence on the lower side of the semiconductor layer 110. The contact portion 121 is connected to the first metal layer 130 through the conductive layer 123. The conductive pillar 160 penetrates the dielectric layer 150 and extends to the second metal layer 140. The upper end of the conductive pillar 160 is connected to the lower surface of the conductive layer 123, and its size in the x direction is less than or equal to the size of the conductive layer 123 in the same direction. The conductive pillar 160 can be used as a connection structure for connecting the second metal layer 140 and the conductive layer 123, so that a plurality of contact portions 121 simultaneously connected to the second metal layer 140 are also electrically connected to each other in an electric field.

[0054] Figure 5 is a schematic diagram of a chip 200 having a semiconductor structure according to an embodiment of the present application. As Figure 5 shown, the first metal layer 130 may be located at the edge of the chip 200, and its planar shape is not limited to one type. In combination withFigure 4 and Figure 5 As shown in Figure 5 , the contact portion 121 is located below the first metal layer 130 at the edge of the chip 200 and is connected to the first metal layer 130.

[0055] It should be noted that the number of the contact portions 121 includes multiple ones, and the multiple contact portions 121 can be connected to the same first metal layer 130 to form electrical connections with each other. The first metal layer 130 can be made of aluminum or copper and serves as a bonding pad during the packaging process.

[0056] Figure 6 is a schematic diagram of forming an initial sample 300 of a semiconductor structure according to an embodiment of the present application. As Figure 6 shown, at least one of a light emission method and a photoresist method can be used to capture a hot spot region in the semiconductor structure, and the leakage contact portion 120' is located within the hot spot; then, the position where the hot spot is located can be marked to form a mark 310; finally, based on the mark 310, the initial sample 300 as Figure 6 shown is cut out. Exemplarily, the size of the hot spot region in the x direction is 1 μm to 20 μm, and a focused ion beam cutting method can be used to cut out the initial sample 300 for subsequent failure region location. It should be noted that since FIB can perform multi-dimensional fine cutting, ion implantation, modification, deposition, and provide PVC observation on semiconductor devices, it has become a powerful means for including modification, ion implantation, cutting, and failure analysis of semiconductor integrated circuits.

[0057] In some embodiments, the steps of using FIB to cut the initial sample 300 include: First, a metal platinum protection layer with a certain size and thickness is deposited centered on the mark 310 region to avoid damage to the mark 310 region by FIB during subsequent sample preparation; then, the two sides of the target sample (i.e., the initial sample 300) to be obtained are hollowed out by FIB, and the same cutting operation is performed on the bottom and side to break it, thereby forming a U-shaped cut. At this time, the target sample only remains connected to the semiconductor device at one end and hangs on the semiconductor device. The purpose of forming the U-shaped cut in this operation is to facilitate subsequent extraction of the target sample using equipment such as a mechanical nano-arm (Easylift); finally, the mechanical nano-arm is adhered to the suspended end of the target sample to provide support, and the connection between the target sample and the semiconductor device is cut by FIB to form the initial sample 300.

[0058] Step S1200, remove the metal layer in the initial sample to obtain a detection sample, wherein the semiconductor layer in the detection sample is grounded. The semiconductor layer in the detection sample is grounded.

[0059] As Figure 7As shown, the initial sample 300 can be transferred onto the sample stage 320, and the semiconductor layer 330 in the initial sample 300 is connected to the sample stage 320. In some embodiments, the sample stage 320 can be grounded through detection devices such as FIB and SEM. It can be understood that the initial sample 300 is grounded via the sample stage 320.

[0060] Exemplarily, the sample stage 320, as a consumable product in a widely used sample extraction process, can be a sample-carrying metal mesh including at least one of a copper mesh or a silicon mesh. In some embodiments, the sample-carrying silicon mesh can be processed from a semiconductor wafer. In some embodiments, the shape of the sample stage 320 in the xy plane includes a semi-circular shape, a circular shape, or other shapes. The sample stage 320 can have a substrate and an attachment portion for placing the initial sample 300. The attachment portion can be connected to the substrate. The placement manner of the initial sample 300 on the attachment portion includes, for example, conductive adhesion. The conductive adhesion between the initial sample 300 and the attachment portion can be achieved through, for example, a conductive adhesive. The surface of the attachment portion that adheres to the initial sample 300 can be parallel to the ion beam emitted by the FIB or can form an angle θ (0 < θ < 180°) with the ion beam, so that the FIB can perform various cutting methods on the initial sample 300, such as tangential cutting, oblique cutting, and positive-oblique cutting.

[0061] Figures 8a to 8b is a process schematic diagram of preparing a detection sample for a semiconductor structure leakage location method according to an embodiment of the present application. As Figure 8a and Figure 8b shown, a part of the initial sample 300 is removed along the first direction (z direction) and the opposite direction of the first direction respectively, and it is thinned until the opposite sides ( Figure 8b the upper surface 121a and the lower surface 121b in

[0062] ) of the contact portion 121 in the initial sample 300 are exposed, thereby forming the detection sample 340. It should be noted that during the process of removing a part of the initial sample 300, the emission direction of the FIB ion beam can be parallel to the y direction. After removing this part of the initial sample 300, the upper side 121a and the lower side 121b of the contact portion 121 can be

[0063] In some other embodiments, the removed part of the initial sample 300 only includes the first metal layer 130 and the second metal layer 140. At this time, the upper surface of the contact part 121 and the lower surface of the conductive post 160 in the detection sample 340 are completely exposed, and the upper surface 121a / lower surface 121b of the remaining part of the contact part 121 can be coplanar with the upper surface of the semiconductor layer 330 / the lower surface of the dielectric layer 150 respectively. The electrical connections between the multiple contact parts 121' in the initial sample 300 are removed. After this process is completed, the remaining parts of the contact parts 121' are no longer electrically connected via the metal layer and are electrically isolated from each other.

[0064] It should be noted that after the above process is completed, the opposite sides of the leakage contact part 120' will also be exposed. However, since there is a short circuit between it and the semiconductor layer 330, when an electric field is applied, the multiple leakage contact parts 120' are not electrically isolated from each other.

[0065] In some embodiments, the initial sample 300 can be finely milled by FIB to obtain the detection sample 340. The cutting direction of the FIB ion beam can be perpendicular to the substrate of the sample stage 320, and it can mill the initial sample 300 along, for example, the y direction. After the cutting of the first surface (such as the upper surface 121a) is completed, the sample stage 320 is rotated by a certain angle (such as 180°), and the cutting of the second surface (such as the lower surface 121b) is continued to form the detection sample 340. Exemplarily, by setting the angle between the sample bonding surface of the attachment part of the sample stage 320 and the substrate of the sample stage 320, different cutting methods such as tangential cutting, oblique cutting, and positive-oblique cutting of the FIB ion beam on the initial sample 300 can be adjusted.

[0066] Step S1300, detect the contact part in the detection sample and locate the leakage contact part based on the detection result.

[0067] After the detection sample 340 is prepared by FIB milling the initial sample 300, at least one of means such as FIB and SEM can be used to detect and analyze the detection sample 340, and it can be recorded and output through, for example, a display device as Figure 9The image shown. Since the leakage contact portion 120' is connected to the semiconductor layer 330, and the semiconductor layer 330 is grounded via the sample stage 320, when electrons or ion beams with a certain energy are emitted onto the surface of the detection sample 340, more secondary electrons are scattered from the grounded leakage contact portion 120' compared to the normal contact portion 121'. Therefore, it appears brighter in contrast in the image, enabling precise localization of the leakage position and a failed contact portion through the difference in voltage contrast. Exemplarily, the acceleration voltage of the FIB ion beam during the detection and analysis of the detection sample 340 can be 1 kV - 30 kV. It should be noted that the greater the acceleration voltage of the FIB ion beam, the higher the energy of the ion beam, the higher the relative emission amount of secondary electrons from the sample surface, and the more obvious the relative voltage contrast. However, when the ion beam energy is too high, for example, exceeding 30 kV, a small potential difference will be generated in the charging area where the electrons on the sample surface interact with the sample body, causing the scattered electron beam to spread and damaging the resolution.

[0068] Figures 10a to 10d is a scanning electron microscope image for precisely locating the leakage contact portion by the leakage location method according to an embodiment of the present application. As Figures 10a to 10d can be seen, after grasping the hot spot area, transferring it to the sample carrier metal mesh and thinning both the front and back sides, by observing the brightness and darkness differences in the voltage contrast of the detection sample, a failed contact portion can be precisely located, which greatly increases the success rate of semiconductor structure failure analysis. Among them, Figure 10c clearly shows the contrast difference caused by the different emission amounts of secondary electrons of the contact portion 121' and the leakage contact portion 120' on both the front and back sides of the detection sample 340 under the bombardment of the FIB ion beam, thereby precisely locating the leakage contact portion 120'. After precisely locating the leakage contact portion 120', only the failure analysis of a single contact portion is required (as Figure 10d shown), which greatly reduces the time cost and machine cost, thereby improving the analysis efficiency and reducing the expenditure.

[0069] On the other hand, the present application also provides a leakage location system. This system precisely locates the leakage contact portion in the above semiconductor structure.

[0070] Figure 11 is a schematic diagram of the leakage location system 400 according to an embodiment of the present application. As Figure 11 shown, the leakage location system 400 can include a sample thinning device 390 and a sample stage 320. The sample thinning device 390 is configured to thin at least a part of the initial sample 300 along the first direction (z direction) and / or the opposite direction of the first direction to obtain the detection sample 340 (refer to Figure 8); the sample stage 320 is configured to ground at least a part of the detection sample 300.

[0071] In some embodiments, the initial sample 300 includes a semiconductor layer 330, a leakage contact portion 120', and a metal layer (refer to Figure 4 ). The leakage contact portion 120' penetrates through the semiconductor layer 330 along the first direction, and includes a conductive layer 123 and an insulating layer 122. The insulating layer 122 surrounds a part of the conductive layer 123 along the first direction. The part of the conductive layer 123 not surrounded by the insulating layer 122 is in contact with the conductor layer 330. The conductive layer 123 is electrically connected via the metal layer 122. The sample thinning device 390 is configured to remove the metal layer along the first direction and / or the opposite direction of the first direction. After the metal layer of the initial sample 300 is removed, a detection sample 340 is formed. In the detection sample 340, the opposite sides of the leakage contact portion 120' parallel to the xy plane are exposed. The sample stage 320 is configured to ground the semiconductor layer 330 in the detection sample 340.

[0072] Exemplarily, the shape of the sample stage 320 in the xy plane can be semi-circular, and it has an attachment portion (not shown) 320 for placing the detection sample 340. The sample stage can be a metal sample grid, including at least one of a copper grid and a silicon grid.

[0073] In some embodiments, the leakage location system 400 further includes a contact portion 121', which can penetrate through the semiconductor layer 330 along the first direction. The structure of the contact portion 121' is similar to that of the leakage contact portion 120', and both are composed of an insulating layer 122 wrapping a conductive layer 123. The difference is that the insulating layer 122 of the contact portion 121' completely wraps the conductive layer 123 around the z-axis direction, isolating it from the semiconductor layer 330. It can be understood that the opposite sides of the contact portion 121' parallel to the xy plane are also exposed. When the exposed surfaces of the contact portion 121' and the leakage contact portion 120' are bombarded by electrons or ion beams, different amounts of secondary electrons are released, so that the contact portion 121' and the leakage contact portion 120' show different voltage contrasts.

[0074] In some embodiments, the detection sample 340 further includes a marker 310, and the leakage contact portion 120' is located within the area of the marker 310. The size of the marker 310 in the direction perpendicular to the first direction (for example, the x direction) can be 1 μm - 20 μm.

[0075] In some embodiments, the leakage location system 400 further includes a detection module 410. The detection module 410 can be a specific detection device, such as including a focused ion beam, a scanning electron microscope and other devices; the detection module 410 can also be a certain detection means, such as including a focused ion beam detection means, a detection means combining a focused ion beam and a scanning electron microscope, etc.

[0076] In some embodiments, the leakage current positioning system 400 further includes an analysis and display module 420. The analysis and display module 420 can be used to record and output a voltage contrast image of the detection sample 340. The analysis and display module 420 is connected to the detection module 410, and can receive the electrical signals transmitted by the detection module and process and convert the electrical signals into a voltage contrast image for output. Exemplarily, the analysis and display module 420 includes a computer or a computer system with computing functions.

[0077] In some embodiments, the leakage current positioning system 400 further includes a positioning module 430. The positioning module 430 accurately locates the leakage contact part 120' by discriminating the voltage contrast difference in the voltage contrast image. Exemplarily, the positioning module 430 can be electrically connected to the analysis and display module 410, and complete the positioning of the leakage contact part 120' through, for example, a compilation program. The positioning module 430 can also be an independent part, such as including an organism with contrast analysis and discrimination capabilities and artificial intelligence, etc.

[0078] In some embodiments, any of the leakage current positioning methods in the embodiments of the present application can be used to accurately locate the leakage position and the leakage contact part 120' through the leakage current positioning system 400.

[0079] The above description is only for the embodiments of the present application and the description of the applied technical principles. Those skilled in the art should understand that the protection scope involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the technical concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. Method for locating leakage current in a semiconductor structure, the semiconductor structure comprising a semiconductor layer, a metal layer, and a plurality of contact portions penetrating the semiconductor layer along a first direction, wherein, the contact portion includes a conductive layer and an insulating layer, the insulating layer surrounds the conductive layer around the first direction, and the conductive layers are electrically connected via the metal layer, and characterized in that the method comprises: extracting an initial sample including a leakage contact portion from the semiconductor structure, wherein the conductive layer in the leakage contact portion is electrically connected to the semiconductor layer; removing the metal layer from the initial sample to obtain a detection sample, wherein the semiconductor layer in the detection sample is grounded, and the metal layer includes a first metal layer and a second metal layer respectively located on both sides of the semiconductor layer in the first direction and connected to the conductive layer; and detecting the contact portions in the detection sample and locating the leakage contact portion based on the detection result.

2. The method according to claim 1, wherein, the step of removing the metal layer from the initial sample includes: thinning the initial sample along the first direction and / or the opposite direction of the first direction to remove the metal layer, wherein the opposite sides of the contact portion in the thinned initial sample are completely exposed.

3. The method according to claim 1, wherein, the steps of detecting the contact portions in the detection sample and locating the leakage contact portion include: irradiating the detection sample with at least one of an ion beam emitted by a focused ion beam or an electron beam emitted by a scanning electron microscope; obtaining a voltage contrast image of the contact portions in the detection sample; and locating the leakage contact portion in the voltage contrast image by passive voltage contrast.

4. The method according to claim 2, wherein, the step of extracting the initial sample includes: grabbing the hot spot of the semiconductor structure by at least one of a light emission method and a photoresistive method, wherein the leakage contact portion is located within the hot spot; marking the hot spot; and cutting out the initial sample based on the marking.

5. The method according to claim 1, wherein, the step of removing the metal layer from the initial sample to obtain the detection sample includes: transferring the initial sample to a sample stage, wherein the semiconductor layer of the initial sample is connected to the sample stage, and the sample stage is grounded; and removing the metal layer from the initial sample to form the detection sample grounded via the sample stage.

6. The method according to claim 5, wherein, the sample stage includes a sample-carrying metal mesh, and the semiconductor layer of the initial sample is located on the sample-carrying metal mesh and grounded via the sample-carrying metal mesh.

7. The method according to claim 4, wherein, the initial sample is obtained by cutting the semiconductor structure using a focused ion beam cutting method.

8. The method according to claim 4, wherein, the size of the hot spot in a direction perpendicular to the first direction is 1 μm - 20 μm.

9. The method according to claim 3, wherein, the acceleration voltage of the focused ion beam is 1 kV - 30 kV.

10. The method according to claim 1, wherein, The semiconductor structure is a 3D NAND memory.

11. Leakage current location system, characterized in that, it includes: A sample thinning device configured to thin at least a part of an initial sample along a first direction and / or the opposite direction of the first direction to obtain a detection sample; and A sample stage configured to ground at least a part of the detection sample; wherein, the initial sample includes a semiconductor layer, a leakage current contact part and a metal layer, the leakage current contact part penetrates the semiconductor layer along the first direction, and includes a conductive layer and an insulating layer, the insulating layer surrounds a part of the conductive layer around the first direction, and the part of the conductive layer not surrounded by the insulating layer is in contact with the semiconductor layer, the conductive layer is electrically connected via the metal layer, and the metal layer includes a first metal layer and a second metal layer that are respectively located on both sides of the semiconductor layer in the first direction and are connected to the conductive layer; wherein, the sample thinning device is configured to remove the metal layer along the first direction and / or the opposite direction of the first direction, and the sample stage is configured to ground the semiconductor layer.

12. The system according to claim 11, further includes: A detection module configured to perform voltage detection on the detection sample by at least one of an ion beam emitted by a focused ion beam or an electron beam emitted by a scanning electron microscope; An analysis and display module configured to record and output a voltage contrast image of the detection sample; and A location module configured to locate the leakage current position in the sample through the contrast difference in the voltage contrast image.

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