Sample preparation method for analyzing section morphology of metal film

Abstract

The invention discloses a sample preparation method for analyzing the section morphology of a metal film, relates to the technical field of sample detection, and aims to solve the problem that a to-be-observed metal sample does not meet the observation requirement due to the fact that extended metal covers the section of the to-be-observed metal film after the metal film is broken. The sample preparation method of the sample for analyzing the section morphology of the metal film comprises the following steps: providing a bearing piece with a first surface and a second surface; forming a metal film on the first surface; forming a tensile protective film on the metal film to obtain a sample to be cut; the stretch-resistant protective film coats the outer side wall of at least one metal film and is used for limiting the deformation quantity of the coated metal film when the coated metal film is cut; cutting the to-be-cut sample along the direction from the first surface to the second surface to obtain a cut sample; the cut surface of the cut sample comprises the cross section of the bearing part, the cross section of the coated metal film and the cross section of the tensile protective film; and removing the tensile protective film to obtain the sample to be observed.

Description

Technical Field

[0001] This invention relates to the field of sample testing technology, and in particular to a sample preparation method for analyzing the cross-sectional morphology of metal thin films. Background Technology

[0002] The fabrication of devices involves multiple layers of metals, such as ohmic metals, gate metals, and interconnect metals. The morphology of each metal layer affects properties such as resistance and capacitance. Therefore, during device fabrication, it is necessary to observe and analyze the cross-sectional morphology of the metal thin film to ensure the quality of the devices fabricated using that metal.

[0003] In existing technologies, a diamond cutter is typically used to directly cut a metal thin film to obtain the segmented metal film. Then, the cross-sectional morphology of the cut metal thin film is observed using a scanning electron microscope, and the cross-sectional morphology of the metal thin film is analyzed and judged.

[0004] However, due to the excellent ductility of metal films, during dissociation and fragmentation, the metal at the segmented location and the metal extending towards both ends of that location undergoes plastic deformation, causing the metal at both ends of the segmented location to break after being stretched. After the metal film breaks, the remaining irregular metal will cover the cross-section of the metal film to be observed, resulting in the final metal sample obtained not meeting the observation requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a sample preparation method for analyzing the cross-sectional morphology of metal thin films, thereby improving the quality of the final metal sample to be observed.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a sample preparation method for analyzing the cross-sectional morphology of metal thin films. This sample preparation method for analyzing the cross-sectional morphology of metal thin films includes:

[0007] First, a carrier is provided; the carrier has a first surface and a second surface that are opposite to each other;

[0008] Next, a thin metal film is formed on the first surface of the carrier;

[0009] Next, a tensile protective film is formed on the outer sidewall of the metal film to obtain the sample to be cut; the tensile protective film covers all the outer sidewalls of at least one metal film and is used to limit the deformation of the covered metal film when it is cut.

[0010] Next, the sample to be cut is cut along the direction from the first surface to the second surface to obtain the cut sample; the cut surfaces of the cut sample include the cross-section of the bearing, the cross-section of the covered metal film, and the cross-section of the tensile protective film.

[0011] Next, the tensile protective film is removed to obtain the sample to be observed.

[0012] Compared with existing technologies, the sample preparation method for analyzing the cross-sectional morphology of metal thin films provided by this invention involves forming a tensile protective film on the outer wall of the metal thin film to obtain the sample to be cut. Furthermore, the tensile protective film covers all outer walls of at least one metal thin film, and serves to limit the deformation of the covered metal thin film during cutting. Therefore, during the actual cutting of the sample, the tensile protective film can reduce or eliminate the plastic deformation generated when the covered metal thin film is cut, reduce or eliminate the lateral tension on the surface of the covered metal thin film and the longitudinal deformation of the cross-section of the covered metal thin film, thereby reducing or eliminating the probability of irregular metal residue covering the cross-section of the metal thin film after fracture (in other words, it can reduce or eliminate the probability of changes in the cross-section after fracture due to metal ductility, such as metal deformation and extended metal covering the cross-section of the metal thin film), thus improving the quality of the final metal sample to be observed. It should be noted that the aforementioned residual irregular metal may cover the boundary of the metal film cross-section (i.e., the metal film cross-sectional boundary) or the internal region of the metal film cross-section. Furthermore, the probability of the boundary between the coated metal film cross-section and the support cross-section can be reduced or eliminated, thereby obtaining a sample that more accurately reflects the boundary between the coated metal film cross-section and the support cross-section. This further improves the quality of the final metal sample to be observed, thereby further improving the accuracy of the observation and analysis of the morphology of the coated metal film cross-section and enhancing the precision of process quality monitoring. In addition, compared to the existing method of using focused ion beam (FIB) sample preparation, the sample preparation method provided by this invention reduces sample preparation costs.

[0013] In one implementation, the metal film has an abutting surface that abuts against the first surface; all edges of the abutting surface of the covered metal film are spaced apart from all edges of the first surface.

[0014] In one implementation, the metal film has an abutting surface that abuts against the first surface; along a first direction, the abutting surface has two opposing first sides, and the first surface has two opposing second sides; along a second direction, the abutting surface has two opposing third sides, and the first surface has two opposing fourth sides; the first direction is perpendicular to the second direction.

[0015] Along the first direction, at least one first side of the covered metal film coincides with the second side; along the second direction, the two third sides and the two fourth sides of the covered metal film are spaced apart.

[0016] In one implementation, the tensile protective film is made of a non-metallic and brittle material.

[0017] In one implementation, the tensile protective film is made of a dielectric film and / or photoresist.

[0018] In one implementation, the dielectric film comprises silicon oxide, silicon nitride, or benzocyclobutene.

[0019] In one implementation, when the material of the tensile protective film includes benzocyclobutene and / or photoresist, the ratio of the thickness of the metal film to the thickness of the tensile protective film is greater than 1.

[0020] When the material of the tensile protective film includes silicon oxide and / or silicon nitride, the ratio of the thickness of the metal film to the thickness of the tensile protective film is greater than 2.

[0021] In one implementation, the cross-section of the covered metal film is the cross-section of the covered metal film; and / or, the metal film is a single-layer metal film or a stack of multiple metal films; and / or, the material of the metal film includes one or more of Al, Au, Pt, Cu, Ti, Ni, and Ge; and / or, the thickness of the metal film is less than 1 micrometer, and the thickness direction of the metal film is consistent with the direction from the first surface to the second surface.

[0022] In one implementation, the material of the carrier includes one or more of silicon, quartz, SiC, sapphire, GaAs, InP, and GaN; and / or, the thickness of the carrier is greater than or equal to 50 μm and less than or equal to 400 μm, and the thickness direction of the carrier is consistent with the direction from the first surface to the second surface; and / or, the first surface of the carrier is a plane parallel to the horizontal plane; and / or, the method of removing the tensile protective film includes dry etching removal or wet etching removal.

[0023] Secondly, the present invention also provides a method for analyzing the cross-sectional morphology of a metal thin film. This method includes observing the cross-section of the metal thin film coated in the sample to be observed, obtained using the sample preparation method described above for analyzing the cross-sectional morphology of a metal thin film, in order to analyze the morphology of the coated metal thin film's cross-section.

[0024] Compared with existing technologies, the sample preparation method for analyzing the cross-sectional morphology of metal thin films described above obtains the sample to be observed by forming a tensile protective film on the outer wall of the metal thin film. Furthermore, the tensile protective film covers all outer walls of at least one metal thin film, limiting the deformation of the covered metal thin film during cutting. Therefore, during the actual cutting process, the tensile protective film can reduce or eliminate the plastic deformation generated when the covered metal thin film is cut, reducing or eliminating the lateral tension on the surface of the covered metal thin film and the longitudinal deformation of the cross-section. This reduces or eliminates the probability of irregular metal residue remaining on the cross-section of the metal thin film after breakage, thereby improving the quality of the final metal sample. Based on this, the accuracy of observing and analyzing the cross-sectional morphology of the metal thin film can be improved, thus enhancing the precise judgment of process quality monitoring. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram of the structure of the carrier and the metal film in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the carrier, metal film, and tensile protective film in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the sample to be cut, with the cutting path drawn in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of the cut sample in an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of the sample to be observed in an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram of the distribution of the metal thin film on the first surface of the carrier in an embodiment of the present invention. Figure 1 ;

[0032] Figure 7 This is a schematic diagram of the distribution of the metal thin film on the first surface of the carrier in an embodiment of the present invention. Figure 2 ;

[0033] Figure 8 This is a schematic diagram of the distribution of the metal thin film on the first surface of the carrier in an embodiment of the present invention. Figure 3 ;

[0034] Figure 9 This is a schematic diagram of the distribution of the metal thin film on the first surface of the carrier in an embodiment of the present invention. Figure 4 ;

[0035] Figure 10 This is an image of the sample under a scanning electron microscope in the existing technology.

[0036] Figure 11 This is an image of the sample under a scanning electron microscope in an embodiment of the present invention;

[0037] Figure 12 This is an image of the sample under observation at a higher magnification scanning electron microscope in an embodiment of the present invention.

[0038] Figure label:

[0039] 1-Bearing component, 10-First side, 100-Second side, 101-Fourth side; 2-Metallic film, 20-Covered metal film, 200-Cross-section of the covered metal film, 201-First side, 202-Third side; 3-Tension protective film. Detailed Implementation

[0040] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0043] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] To address the aforementioned technical problems, in a first aspect, embodiments of the present invention provide a sample preparation method for analyzing the cross-sectional morphology of metal thin films. This sample preparation method for analyzing the cross-sectional morphology of metal thin films includes:

[0046] Step 101: See Figure 1 A carrier 1 is provided, the carrier 1 having a first surface 10 and a second surface ( ) opposite to each other. Figure 1 (not shown in the image);

[0047] As one possible implementation, the material of the support includes one or more of silicon, quartz, SiC, sapphire, GaAs, InP, and GaN. For example, the support can be a structure formed by epitaxially growing GaN on SiC or sapphire.

[0048] The thickness of the aforementioned support component can be set according to actual conditions, as long as it ensures that the support component can be easily cut during subsequent cutting. As one possible implementation, the thickness D of support component 1 is greater than or equal to 50 μm and less than or equal to 400 μm, and the thickness direction of support component 1 is consistent with the direction from the first surface to the second surface. For example, the thickness D of support component 1 can be 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 200 μm, 250 μm, 280 μm, 300 μm, 320 μm, 350 μm, 380 μm, or 400 μm, etc.

[0049] Step 102: See Figure 1 A metal film 2 is formed on the first surface 10 of the support member 1;

[0050] For example, a metal thin film 2 is deposited on the first surface 10 of the semiconductor material carrier 1.

[0051] The first surface of the aforementioned carrier can be a plane parallel to the horizontal plane or a surface with a certain slope, as long as it can be used to form a metal thin film, and no specific limitation is made here.

[0052] As one possible implementation, see Figure 1 The first surface 10 of the aforementioned carrier 1 is a plane parallel to the horizontal plane. This not only provides a good foundation for forming the metal thin film and ensures the uniformity of the metal thin film thickness, but also facilitates subsequent processing using methods such as photolithography to form the metal thin film.

[0053] The number and size of the metal thin film formed on the first surface of the aforementioned carrier can be set according to actual needs. For example, see [link to example]. Figures 6 to 9 A single metal film 2 can be formed on the first surface 10 of the carrier 1, or multiple metal films 2 can be formed. When multiple metal films 2 are formed, they can be arranged in an array, or they can be arranged in other ways according to actual needs.

[0054] Step 103: See Figure 1 and Figure 2 A tensile protective film 3 is formed on the outer side wall of the metal film 2 to obtain the sample to be cut; the tensile protective film 3 covers all the outer side walls of at least one metal film 2 and is used to limit the deformation of the covered metal film 20 when it is cut.

[0055] For ease of description, the side of the metal film 2 that abuts against the first surface 10 of the carrier 1 is defined as the abutting surface. The outer sidewall of the metal film 2 refers to all exposed surfaces other than the abutting surface. The aforementioned covering refers to the tensile protective film 3 being tightly adhered to all exposed outer sidewalls of the metal film 2. It should be noted that... Figure 2 and Figure 3 The tensile protective film 3 should completely cover all outer walls of the metal film 2. However, to facilitate understanding and observation of the relative positional relationship between the tensile protective film and the metal film, an attached diagram is provided. Figure 2 and attached Figure 3 The tensile protective film on one outer wall of the metal film was removed. Similarly, the attached diagram was drawn. Figure 4 hour, Figure 4 The tensile protective film on the outer wall of the metal film was also removed.

[0056] Based on the foregoing description, to cover all outer walls of the metal film, the tensile protective film can be formed simultaneously on both the outer walls of the metal film and at least a portion of the side walls of the carrier; or, the tensile protective film can be formed simultaneously on both the first surface of the carrier and the outer walls of the metal film. Alternatively, the tensile protective film can be partially formed on the first surface of the carrier, partially formed on the side walls of the carrier, and partially formed on the outer walls of the metal film. It should be noted that the positional relationship of the tensile protective film relative to the carrier can be set according to actual needs and is not specifically limited here, as long as it ensures that the tensile protective film is formed on all outer walls of the metal film and that the tensile protective film covers the metal film. See also Figure 2 In this embodiment of the invention, the length of the metal film is equal to the width of the carrier, and the width of the metal film is less than the length of the carrier. In this case, the tensile protective film is partially formed on the first surface of the carrier, partially formed on the sidewall of the carrier, and partially formed on the outer sidewall of the metal film, thus covering all the outer sidewalls of the metal film.

[0057] Step 104: See Figure 3 and Figure 4 The sample to be cut is cut along the direction from the first surface to the second surface to obtain the cut sample. The cut surface of the cut sample includes the cross section of the bearing 1, the cross section 200 of the covered metal film, and the cross section of the tensile protective film 3. Since the cut surface of the cut sample includes the cross section 200 of the covered metal film, the cutting path L must be located above the covered metal film 20.

[0058] For example, a diamond cutter is used to dissociate and cleave the sample to be cut to obtain the cut sample. The specific operation process can be found in existing diamond cutter dissociation and cleaving procedures, and will not be described in detail here. Furthermore, the cross-section of the aforementioned coated metal film can be a cross-section, a longitudinal section, or a section at other angles. Preferably, see [link to relevant documentation]. Figure 4 and Figure 5 The cross-section of the aforementioned coated metal film is its cross-section. Observing and analyzing the cross-section of the coated metal film can further improve the accuracy of the cross-sectional analysis of the metal film, thereby further enhancing the precise judgment of process quality monitoring.

[0059] Step 105: See Figure 5 Remove the tensile protective film 3 to obtain the sample to be observed. Note that the "sample to be observed" here is the "sample used to analyze the cross-sectional morphology of the metal thin film".

[0060] One possible method for removing the tensile protective film includes dry etching or wet etching; the specific removal process will not be described in detail here.

[0061] Compared with existing technologies, the sample preparation method for analyzing the cross-sectional morphology of metal thin films provided in this invention involves forming a tensile protective film on the outer wall of the metal thin film to obtain the sample to be cut. Furthermore, the tensile protective film covers all outer walls of at least one metal thin film, limiting the deformation of the covered metal thin film during cutting. Therefore, during the actual cutting of the sample, the tensile protective film can reduce or eliminate the plastic deformation generated when the covered metal thin film is cut, reducing or eliminating the lateral stretching of the covered metal thin film surface and the longitudinal deformation of the covered metal thin film cross-section. This reduces or eliminates the probability of irregular metal residue covering the cross-section of the metal thin film after fracture (in other words, it reduces or eliminates the probability of cross-sectional changes due to metal ductility, such as metal deformation and extended metal covering the cross-section of the metal thin film), thereby improving the quality of the final metal sample obtained. It should be noted that the aforementioned residual irregular metal may cover the boundary of the metal film cross-section (i.e., the metal film cross-sectional boundary) or the internal region of the metal film cross-section. Furthermore, the probability of the boundary between the coated metal film cross-section and the support cross-section can be reduced or eliminated, thereby obtaining a sample that more accurately reflects the boundary between the coated metal film cross-section and the support cross-section. This further improves the quality of the final metal sample to be observed, thereby further improving the accuracy of the observation and analysis of the morphology of the coated metal film cross-section and enhancing the precision of process quality monitoring. In addition, compared to the existing method of using focused ion beam (FIB) sample preparation, the sample preparation method provided by this invention reduces sample preparation costs.

[0062] The following description uses two possible scenarios to illustrate the coated metal film. It should be understood that the following description is for illustrative purposes only and is not intended to limit the specific application of the technology.

[0063] As one possible implementation, see Figure 6 and Figure 7 The metal film 2 has an abutting surface that abuts against the first surface 10; all edges of the abutting surface of the covered metal film 20 are spaced apart from all edges of the first surface 10.

[0064] Example 1: See Figure 6When multiple metal films 2 arranged in an array are formed on the first surface 10 of the support member 1, the tensile protective film 3 only covers the metal films 2 away from the edge of the support member 1 (for ease of description, it is simply referred to as the inner metal film). As for the metal film 2 whose edge of the contact surface coincides with the edge of the first surface 10 (for ease of description, it is simply referred to as the edge metal film), the tensile protective film may cover it or may only be formed on part of the outer sidewall of the edge metal film.

[0065] See Figure 6 In the actual cutting process, the cutting path L avoids positions where the entire area consists of edge metal films, and these edge metal films are not used for observation and analysis. Of course, if the circumference of the internal metal film is entirely composed of edge metal films, it is inevitable that the edge metal films will be cut during the cutting process. However, in the later observation and analysis, it is possible to choose not to observe the edge metal films and only observe and analyze the internal metal films.

[0066] Example 2: See Figure 7 When a metal film 2 (i.e., an attachment) is formed in the central region of the first surface 10 of the support member 1 Figure 7 When the metal film 20 is covered in the first surface 10, and all the edges of the contact surface of the metal film 2 are spaced apart from all the edges of the first surface 10, the tensile protective film 3 covers the metal film 2.

[0067] As another possible implementation, see Figure 8 and Figure 9 The metal film 2 has an abutting surface that abuts against the first surface 10. Along the first direction A, the abutting surface has two opposing first edges 201, and the first surface 10 has two opposing second edges 100. Along the second direction B, the abutting surface has two opposing third edges 202, and the first surface 10 has two opposing fourth edges 101. The first direction A is perpendicular to the second direction B. Along the first direction A, at least one first edge 201 of the covered metal film 20 coincides with a second edge 100; along the second direction B, the two third edges 202 and the two fourth edges 101 of the covered metal film 20 are spaced apart.

[0068] Example 1: See Figure 8 Along the first direction A, the two first sides 201 and two second sides 100 of the covered metal film 20 coincide respectively; along the second direction B, when the two third sides 202 and two fourth sides 101 of the covered metal film 20 are evenly distributed, the tensile protective film 3 covers the metal film 2. In the actual cutting process, the cutting path L is located on the metal film 2 (i.e., the attached...). Figure 8The upper surface of the metal film 20) is covered by the cutting path, and the specific location of the cutting path can be set according to actual needs. In this embodiment of the invention, the cutting path L is perpendicular to the first side 201, and the cutting path L coincides with the center line of the metal film 2.

[0069] Example 2: See Figure 9 Along the first direction A, one first side 201 of the covered metal film 20 coincides with the nearest second side 100, and the other first side 201 is spaced apart from the nearest second side 100; along the second direction B, when the two third sides 202 and two fourth sides 101 of the covered metal film 20 are spaced apart, the tensile protective film 3 covers the metal film 2. In the actual cutting process, the cutting path L is located on the metal film 2 (i.e., the attached...). Figure 9 The upper surface of the metal film 20 covered in the film.

[0070] As one possible implementation, the tensile protective film is made of a non-metallic and brittle material. In this case, the tensile protective film does not possess significant plastic deformation capacity, which can reduce or eliminate the probability of deformation of the tensile protective film during the actual cutting of the sample, thereby ensuring that the tensile protective film is used to limit the deformation of the metal film when it is cut.

[0071] As one possible implementation, the materials of the aforementioned tensile protective film include dielectric films and / or photoresists.

[0072] In one alternative embodiment, the dielectric film comprises silicon oxide, silicon nitride, or benzocyclobutene (BCB). As is generally known, benzocyclobutene differs significantly from silicon oxide and silicon nitride, with different preparation methods and applications. However, in this application, silicon oxide, silicon nitride, or benzocyclobutene can all be used to fabricate the tensile protective film, increasing selectivity.

[0073] In one alternative, the photoresist can be 9920 photoresist, 955 photoresist, AZ5214 photoresist, PMMA photoresist, 4400 photoresist, etc.

[0074] As one possible implementation, the thickness of the metal thin film is less than 1 micrometer, and the thickness direction of the metal thin film is consistent with the direction from the first surface to the second surface.

[0075] Because the thickness of a metal film is on the micrometer scale and its size is extremely small, it is difficult to form a metal film without a carrier, and it is also difficult to perform subsequent cutting operations.

[0076] In one alternative, when the material of the tensile protective film includes benzocyclobutene and / or photoresist, the ratio of the thickness of the metal film to the thickness of the tensile protective film is greater than 1.

[0077] In another alternative, when the material of the tensile protective film includes silicon oxide and / or silicon nitride, the ratio of the thickness of the metal film to the thickness of the tensile protective film is greater than 2, which ensures that the silicon oxide and / or silicon nitride completely encapsulate and cover the metal film.

[0078] As one possible implementation, the metal thin film can be a single-layer metal thin film or a stack of multiple metal thin films. This expands the applicability of the above sample preparation method to meet different sample preparation needs.

[0079] Furthermore, when the metal film is a multilayer metal film stack, the tensile protective film can not only reduce or eliminate the plastic deformation generated when the metal film is cut, thereby reducing or eliminating the probability of irregular metal residue remaining on the cross-section of the metal film to be observed after the metal film breaks; at the same time, it can also reduce or eliminate the probability of the interface between the cross-sections of the multilayer metal films being covered, as well as the probability of the interface between the cross-section of the metal film and the cross-section of the support component being covered, thereby further improving the quality of the final metal sample to be observed, and thus further improving the accuracy of the observation and analysis of the cross-sectional morphology of the metal film, and enhancing the accurate judgment of process quality monitoring.

[0080] The sample preparation method provided in this embodiment of the invention is applicable to metal thin films of all materials. For example, the materials of the metal thin films include one or more of Al, Au, Pt, Cu, Ti, Ni, and Ge.

[0081] Secondly, embodiments of the present invention also provide a method for analyzing the cross-sectional morphology of a metal thin film. This method includes observing the cross-section of the metal thin film coated in the sample to be observed, obtained using the sample preparation method described above for analyzing the cross-sectional morphology of a metal thin film, in order to analyze the morphology of the coated metal thin film's cross-section.

[0082] For example, a scanning electron microscope (SEM) can be used to observe the cross-section of the metal thin film of the sample to be observed in order to analyze the morphology of the cross-section of the metal thin film.

[0083] Compared with existing technologies, the sample preparation method for analyzing the cross-sectional morphology of metal thin films described above obtains the sample to be observed by forming a tensile protective film on the outer wall of the metal thin film. Furthermore, the tensile protective film covers all outer walls of at least one metal thin film, limiting the deformation of the covered metal thin film during cutting. Therefore, during the actual cutting process, the tensile protective film can reduce or eliminate the plastic deformation generated when the covered metal thin film is cut, reducing or eliminating the lateral tension on the surface of the covered metal thin film and the longitudinal deformation of the cross-section. This reduces or eliminates the probability of irregular metal residue remaining on the cross-section of the metal thin film after breakage, thereby improving the quality of the final metal sample. Based on this, the accuracy of observing and analyzing the cross-sectional morphology of the metal thin film can be improved, thus enhancing the precise judgment of process quality monitoring.

[0084] The following uses the existing technology and the sample prepared in this application as examples to observe and analyze the sample using a scanning electron microscope.

[0085] See Figure 10 , Figure 10 The image shown is an illustration of the sample under a scanning electron microscope, as presented in the current technology. Figure 10 Region C shows the morphology of the normal metal film cross-section. Region D shows the morphology of the top metal layer after being stretched and extended into the normal metal film cross-section due to its ductility. Region E shows the morphology of the stretched metal layer covering the normal metal film cross-section, obscuring its long and short sides. As can be seen, regions D and E of the sample under observation in the prior art are unfavorable for electron microscopy observation.

[0086] See Figure 11 , Figure 11 The image shown is an image of the sample to be observed in this application under a scanning electron microscope. Figure 11 Region F in the figure shows the morphology of the cross-section of the coated metal film. As can be seen from the figure, the edges of the coated metal film cross-section are neat and without... Figure 10 The phenomenon of a metal section being covered by tensile stress.

[0087] See Figure 12 , Figure 12 The image shown is an image of the sample to be observed in this application under a scanning electron microscope at a higher magnification. Figure 12 The middle G region shows the morphology of the cross-section of the covered metal film. As can be seen from the figure, the edges of the covered metal film cross-section are neat and there is no stretching phenomenon.

[0088] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0089] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A sample preparation method for analyzing the cross-sectional morphology of metal thin films, characterized in that, include: A carrier is provided; the carrier has opposing first and second surfaces; A thin metal film is formed on the first surface of the carrier; A tensile protective film is formed on the outer wall of the metal film to obtain the sample to be cut; The tensile protective film covers all outer walls of at least one of the metal films, and the tensile protective film is used to limit the deformation of the covered metal film when it is cut. The sample to be cut is cut along the direction from the first surface to the second surface to obtain the cut sample; The cut surface of the sample after cutting includes the cross-section of the bearing, the cross-section of the covered metal film, and the cross-section of the tensile protective film; Remove the tensile protective film to obtain the sample to be observed.

2. The sample preparation method for analyzing the cross-sectional morphology of metal thin films according to claim 1, characterized in that, The metal film has an abutting surface that abuts against the first surface; all edges of the abutting surface of the covered metal film are spaced apart from all edges of the first surface.

3. The sample preparation method for analyzing the cross-sectional morphology of metal thin films according to claim 1, characterized in that, The metal film has an abutting surface that abuts against the first surface; along a first direction, the abutting surface has two opposing first sides, and the first surface has two opposing second sides; along a second direction, the abutting surface has two opposing third sides, and the first surface has two opposing fourth sides; the first direction is perpendicular to the second direction; Along the first direction, at least one first side of the covered metal film coincides with the second side; along the second direction, the two third sides and the two fourth sides of the covered metal film are spaced apart.

4. The sample preparation method for analyzing the cross-sectional morphology of metal thin films according to claim 1, characterized in that, The tensile protective film is made of a non-metallic and brittle material.

5. The sample preparation method for analyzing the cross-sectional morphology of metal thin films according to claim 1 or 4, characterized in that, The tensile protective film is made of dielectric film and / or photoresist.

6. The sample preparation method for analyzing the cross-sectional morphology of metal thin films according to claim 5, characterized in that, The dielectric film includes silicon oxide, silicon nitride, or benzocyclobutene.

7. The sample preparation method for analyzing the cross-sectional morphology of metal thin films according to claim 6, characterized in that, When the material of the tensile protective film includes benzocyclobutene and / or photoresist, the ratio of the thickness of the metal film to the thickness of the tensile protective film is greater than 1. When the material of the tensile protective film includes silicon oxide and / or silicon nitride, the ratio of the thickness of the metal film to the thickness of the tensile protective film is greater than 2.

8. The sample preparation method for analyzing the cross-sectional morphology of metal thin films according to claim 1, characterized in that, The cross-section of the covered metal film is the cross-sectional area of ​​the covered metal film; And / or, the metal film is a single-layer metal film or a stack of multiple metal films; And / or, the material of the metal thin film includes one or more of Al, Au, Pt, Cu, Ti, Ni, and Ge; And / or, the thickness of the metal film is less than 1 micrometer, and the thickness direction of the metal film is consistent with the direction from the first surface to the second surface.

9. The sample preparation method for analyzing the cross-sectional morphology of metal thin films according to claim 1, characterized in that, The material of the carrier includes one or more of silicon, quartz, SiC, sapphire, GaAs, InP, and GaN; And / or, the thickness of the support member is greater than or equal to 50 μm and less than or equal to 400 μm, and the thickness direction of the support member is consistent with the direction from the first surface to the second surface; And / or, the first surface of the carrier is a plane parallel to the horizontal plane; And / or, the method of removing the tensile protective film includes dry etching removal or wet etching removal.

10. A method for analyzing the cross-sectional morphology of a metal thin film, characterized in that, include: The cross-section of the metal film covered in the sample to be observed is obtained by the sample preparation method for analyzing the cross-sectional morphology of the metal film as described in any one of claims 1 to 9, in order to analyze the morphology of the cross-section of the covered metal film.

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