Method for cutting section of semiconductor device
Through the combination method of mechanical grinding and argon ion cross-section polishing, the problem of difficult to achieve large-scale, accurate positioning and no stress deformation in the prior art semiconductor sample cross-section cutting is solved, and efficient and accurate cross-section cutting is achieved, which simplifies process steps and saves time.
Patent Information
- Application Number
- CN202411669630.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-03-28
AI Technical Summary
The existing semiconductor sample cross-sectional cutting technology cannot achieve large-scale, precise positioning, and stress-free cross-sectional cutting at the same time. The process is cumbersome, the equipment costs are high, and the cutting time is long.
The semiconductor device is directly ground in the first direction to the cross section to be cut by mechanical grinding and manual grinding and polishing, and then argon ion cutting with preset cutting parameters is performed on the first surface of the baffle through argon ion cross section polishing to realize nano-scale cutting of the cross section to be cut.
Accurate positioning and stress-free cross-section cutting is achieved, process steps are simplified, cutting time is reduced (from 30 minutes to 5 minutes), and secondary cutting can be performed on adjacent areas of the target cutting section to achieve large-scale cutting of continuous areas.
Smart Images
Figure CN119704416A_ABST
Abstract
Description
Technical Field
[0001] The disclosed embodiments belong to the technical field of semiconductor cross-section cutting, and specifically relate to a semiconductor device cross-section cutting method. Background Art
[0002] In the process of developing and producing semiconductor devices, it is often necessary to observe the internal conditions of the sample to check for internal defects (such as delamination of the bonding surface, fine cracks, etc.) to achieve the purpose of improvement, optimization and acceptance. In order to obtain accurate results, it is very important to cut the sample at the position to be observed. At present, the cutting methods for sample cross-sections include conventional manual cutting and grinding, focused ion beam cutting, argon ion plane polishing and argon ion cross-section polishing.
[0003] Manual grinding is to grind and polish to the specified position manually using a grinder, sandpaper, and polishing fluid, such as Figure 1 As shown, this method often cannot completely remove surface scratches and deformation caused by stress, which affects the accurate judgment of detailed structures. Focused ion beam cutting, argon ion plane polishing, and argon ion cross-section polishing all achieve stress-free cutting by bombarding the atoms on the sample surface with ion beams. Among them, the cutting width of focused ion beam cutting can only be at the micro-nano level, which cannot achieve large-scale observation, and the equipment cost is high. Argon ion plane polishing irradiates the sample surface with an argon ion beam at a certain angle (0°~90°). The argon ions collide with the atoms on the solid surface to flatten the sample and achieve a polishing effect. When this processing method is combined with manual grinding, it can have a certain polishing effect on the cross section, such as Figure 2 As shown, it cannot reduce the deformation damage caused by early manual grinding.
[0004] Existing argon ion cross-section polishing methods (such as Figure 3 ) It is necessary to first expose the upper surface of the material layer 4 to which the sample is thinned by manual flat grinding in the Z direction, and then grind the sample to a point close to the cross section to be observed by manual grinding in the Y direction. Next, the sample loader is centered in the position to be observed in the X direction, and the baffle shields half of the exposed part of the material layer 4. After fixing the baffle, argon ion cross-section polishing is performed. Argon ion cross-section polishing is performed by installing a baffle between the sample and the ion source, slightly raising the part of the sample to be cut above the baffle, and irradiating the sample with an ion beam from above the baffle, cutting a flat cross section of the sample along the edge of the baffle.
[0005] Compared with focused ion beam cutting, argon ion cross-section polishing has a larger cutting range, which can reach the millimeter level. Compared with argon ion plane polishing, argon ion cross-section polishing can completely remove the deformation damage caused by manual grinding. Figure 4As shown, the current argon ion cross-section polishing method requires the operator to accurately control the protrusion p of the sample protruding from the baffle. The protrusion p will affect the cutting depth and cutting thickness h. If the protrusion p is too large, the cutting depth may be small and water ripples may exist in the cutting section. If the protrusion p is too small, the cutting thickness h may be too small and the position to be observed may not be cut. In addition, during argon ion cross-section polishing, as the cutting depth increases, the energy of the ion beam decays and the cutting width decreases. Therefore, the cut section is often a trapezoidal section (such as Figure 4 b) When we need to continue processing and observing the adjacent area of the sample where the sample has been cut, an ion beam cutting blind area will appear. If the blind area is cut a second time, the cutting light thickness at the overlapping position will be too large, and the position that needs to be observed will be directly cut off.
[0006] In summary, the existing semiconductor sample cross-section cutting processing method has the following problems:
[0007] 1) Manual grinding will cause stress deformation and foreign matter embedding, affecting the judgment of details.
[0008] 2) Argon ion plane polishing can only be used for auxiliary polishing after manual grinding and cannot reduce the stress deformation caused by manual grinding.
[0009] 3) The cutting area of focused ion beam cutting is small and can only reach a micro-nano-level cutting width, which cannot be observed over a large range, and the equipment cost is high.
[0010] 4) The existing argon ion cross-section polishing method has a more complicated process and relies on the operator's precise control of the flat grinding depth and grinding stop position as well as the protrusion p of the sample protruding from the baffle. It cannot achieve precise positioning, and it takes 30 minutes to cut a single cross section, which is a long cutting time. In addition, the existing argon ion cross-section polishing method has a blind area for cutting, and it is impossible to achieve large-scale cutting through secondary processing of adjacent areas.
[0011] In summary, the existing cross-section cutting technology cannot simultaneously achieve large-scale, precisely positioned, and stress-free cross-section cutting.
[0012] In view of the above problems, it is necessary to propose a semiconductor device cross-section cutting method that is reasonably designed and effectively solves the above problems. Summary of the invention
[0013] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art and provide a method for cutting a semiconductor device cross section.
[0014] The present disclosure provides a semiconductor device cross-section cutting method.
[0015] The law includes:
[0016] A semiconductor device, a baffle and a sample stage are provided, wherein the semiconductor device is made of a plurality of different materials, the baffle has a first surface and a second surface arranged opposite to each other, and the height of the first surface is higher than the height of the second surface;
[0017] The semiconductor device is directly ground along a first direction to a cross section to be cut by mechanical grinding and manual grinding and polishing;
[0018] Fix the semiconductor device between the sample stage and the second surface of the baffle, wherein the first surface of the baffle is arranged away from the sample stage, and adjust the positions of the baffle and the semiconductor device so that the section to be cut is exposed and located in the center in the second direction, and the section to be cut is flush with the plane where the highest point of the baffle is located;
[0019] The first surface of the baffle is subjected to argon ion cutting with preset cutting parameters by using an argon ion cross-section polishing method, so as to cut the cross section to be cut to obtain a target cutting cross section.
[0020] Optionally, the cutting thickness of the cross section to be cut is the difference between the height of the first surface of the baffle and the height of the second surface thereof.
[0021] Optionally, the preset cutting parameters include: eccentricity is 0, acceleration voltage range is 2KV~8KV, gas flow range is 0.07cm 3 / min~0.1cm 3 / min, and the cross-section grinding time ranges from 4min to 6min.
[0022] Optionally, the argon ion cross-section polishing method is used to perform argon ion cutting on the first surface of the baffle with preset cutting parameters to cut the cross section to be cut to obtain a target cutting cross section, including:
[0023] The semiconductor device fixed in position is placed in an ion polisher, an argon ion cross-section polishing mode is selected, and the first surface of the baffle is bombarded with argon ions with the preset cutting parameters to complete the cutting of the baffle;
[0024] After the baffle is cut, the section to be cut is bombarded with argon ions to obtain the target cutting section.
[0025] Optionally, after cutting the section to be cut to obtain a target cutting section, the method further includes:
[0026] Cutting is performed on the adjacent to-be-cut surface of the target cutting section.
[0027] Optionally, the cutting of the adjacent to-be-cut surface of the target cutting section includes:
[0028] Centering the edge point of the target cutting section along the second direction between the sample stage and the second surface of the baffle, and aligning the adjacent to-be-cut surface with the plane where the highest point of the baffle is located;
[0029] The first surface of the baffle is again subjected to argon ion cutting with the preset cutting parameters by using argon ion cross-section polishing to cut the adjacent to-be-cut surfaces to obtain adjacent target cutting cross-sections.
[0030] Optionally, the target cutting section and the section of the cutting overlapping area between the adjacent target cutting sections are still in the position to be observed.
[0031] Optionally, after cutting the section to be cut to obtain a target cutting section, the method further includes:
[0032] A scanning electron microscope is used to perform high-magnification observation of the interface between different materials on the target cutting section.
[0033] Optionally, the step of directly grinding the semiconductor device along the first direction to a cross section to be cut by mechanical grinding and manual grinding and polishing includes:
[0034] The semiconductor device is directly ground to the section to be cut along the first direction by using a grinder, sandpaper with different meshes, a polishing cloth and a polishing liquid; wherein the mesh of the sandpaper ranges from 80 meshes to 4000 meshes.
[0035] Optionally, when the semiconductor device is fixed between the sample stage and the second surface of the baffle, the height of the sample stage is lower than the height of the cross section to be cut.
[0036] The semiconductor device cross-section cutting method of the disclosed embodiment first manually grinds the semiconductor device to the cross-section to be cut to achieve precise positioning, and then performs argon ion cross-section polishing to achieve nano-scale cutting of the cross-section to be cut. The process steps are simple and the stress caused by manual grinding is completely eliminated to better observe the bonding between different materials inside the semiconductor device. The adjacent area of the target cutting cross-section can be cut a second time. Because the thickness of a single cut is small, even if the adjacent area is cut a second time, the cutting thickness of the overlapping area is also very small, and the position that needs to be observed will not be cut through, thereby achieving large-scale cutting of continuous areas. When polishing the same cross-sectional area, the cutting time is greatly reduced (from 30 minutes to 5 minutes), saving time. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1This is a SEM image of a sample that is manually ground to a target cross section in the prior art;
[0038] Figure 2 This is a SEM image of a sample after being manually ground to a target cross section using argon ion plane polishing in the prior art;
[0039] Figure 3 It is a schematic diagram of the process of cutting a sample cross section using an argon ion cross section polishing process in the prior art;
[0040] Figure 4 It is a schematic diagram of the structure when argon ion cross-section polishing is used in the prior art;
[0041] Figure 5 A schematic diagram of a process of a semiconductor device cross-section cutting method in an embodiment of the present disclosure;
[0042] Figure 6 is a schematic structural diagram of a semiconductor device in an embodiment of the present disclosure;
[0043] Figure 7 It is a schematic diagram of the structure when the cross section to be cut is cut by using the argon ion cross section polishing method in the embodiment of the present disclosure and a schematic diagram of the target cutting cross section;
[0044] Figure 8 A schematic diagram of a process flow of a semiconductor device cross-section cutting method according to an embodiment of the present disclosure;
[0045] Fig. 9 The overall SEM image and the magnified image of the bonding surface are obtained by manually grinding the cross section to be cut in the embodiment of the present disclosure;
[0046] Fig.10 This is a SEM image of the cut section after secondary processing of the adjacent area of the target cut section obtained by cutting in the embodiment of the present disclosure. DETAILED DESCRIPTION
[0047] In order to enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, the embodiments of the present disclosure are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.
[0048] like Figure 5 As shown, the embodiment of the present disclosure provides a semiconductor device cross-section cutting method S100, the method S100 comprising:
[0049] S110, providing a semiconductor device, a baffle and a sample stage, wherein the semiconductor device is made of a plurality of different materials, the baffle has a first surface and a second surface that are oppositely disposed, and a height of the first surface is higher than a height of the second surface.
[0050] Specifically, Figure 6As shown, a semiconductor device 110 is provided, and the semiconductor device 110 is composed of a plurality of different materials, and different material layers are stacked in sequence. Among them, material layer 1 and material layer 2 are external materials and can be directly observed, and material layer 3 and material layer 4 are coated by material layer 1 and material layer 2 inside the semiconductor device 110, and the external material layer 1 and material layer 2 need to be processed and cut before they can be observed. The cross-sectional cutting method provided in the embodiment of the present disclosure can observe the bonding interface between material layer 1, material layer 2, material layer 3 and material layer 4.
[0051] It should be noted that the structure of the semiconductor device 110 in the embodiment of the present disclosure is not limited to the four material layers mentioned above, and may be other structures and other material layers.
[0052] like Figure 7 As shown, a baffle 120 and a sample stage 130 are provided. The baffle 120 has a first surface 121 and a second surface 122 that are arranged opposite to each other, and the height of the first surface 121 is higher than the height of the second surface 122. That is, the top wall of the first surface 121 is inclined toward the top wall of the second surface 122.
[0053] S120, manually grinding the semiconductor device along a first direction directly to a cross section to be cut.
[0054] Specifically, Figure 8 As shown, a grinder, sandpapers of different meshes, polishing cloths and polishing liquid are used to grind the semiconductor device 110 directly along the Y-axis direction to the section A to be cut. The mesh of the sandpaper ranges from 80 mesh to 4000 mesh. The corresponding sandpaper mesh can be selected for grinding according to the thickness of different material layers.
[0055] It should be noted that the direction of manual grinding of the semiconductor device 110 can be limited according to actual needs and is not limited to the Y-axis direction in the embodiment of the present disclosure.
[0056] In this embodiment, the semiconductor device is firstly directly ground to the cross section to be cut by manual grinding to achieve precise positioning.
[0057] S130. Fix the semiconductor device between the sample stage and the second surface of the baffle, wherein the first surface of the baffle is arranged away from the sample stage, and adjust the positions of the baffle and the semiconductor device so that the cross section to be cut is exposed and located in the center in the second direction, and the cross section to be cut is flush with the plane where the highest point of the baffle is located.
[0058] Specifically, Figure 7As shown in the figure, the semiconductor device 110, which is manually ground to expose the section A to be cut, is fixed on the sample stage 130 and the second surface 122 of the baffle 120. That is, as shown in the figure, the lower surface of the material layer 2 of the semiconductor device 110 is bonded to the sample stage, and the upper surface of the material layer 1 of the semiconductor device 110 is bonded to the second surface 122 (the lower side of the baffle 120) of the baffle 120. The positions of the baffle 120 and the semiconductor device 110 are adjusted under an optical microscope by a high-precision sample loader, as shown in the figure. Figure 7 As shown, the section A to be cut is exposed and located in the center in the X-axis direction, and the section A to be cut is flush with the plane where the highest point of the baffle 120 is located.
[0059] When the semiconductor device 110 is fixed between the sample stage 130 and the second surface 122 of the baffle 120 , the height of the sample stage 130 is lower than the height of the section A to be cut. This can prevent the sample stage 130 from being cut when the section A to be cut is further cut.
[0060] S140, using argon ion cross-section polishing to perform argon ion cutting on the first surface of the baffle with preset cutting parameters, so as to cut the cross section to be cut to obtain a target cutting cross section.
[0061] Specifically, the semiconductor device 110 with a fixed position is placed in an ion polisher, and the argon ion cross-section polishing mode is selected to perform argon ion cutting with preset cutting parameters. The preset cutting parameters are: eccentricity is 0, acceleration voltage range is 2KV to 8KV, gas flow range is 0.07cm 3 / min~0.1cm 3 / min, the cross-section grinding time ranges from 4min to 6min, wherein the cross-section grinding time is preferably 5min.
[0062] like Figure 7 As shown, the argon ion source B bombards the first surface 121 of the baffle 120 with argon ions to complete the cutting of the baffle 120, wherein the area C is the area of the baffle 120 bombarded by the argon ions. After the cutting of the baffle 120 is completed, the section A to be cut is bombarded with argon ions to cut the section A to be cut to obtain the target cutting section. Figure 7 As shown in a, L is the cutting depth and H is the cutting thickness. Figure 7 b is a schematic diagram of the cross section after cross section cutting using the cutting method of an embodiment of the present disclosure, d is a single cutting cross section, and e is the total cutting cross section after multiple processing.
[0063] For example, Figure 7As shown, in this embodiment, the cutting thickness of the section A to be cut is the difference between the height of the first surface 111 of the baffle 120 and the height of the second surface 112. The height difference of the baffle 120 can limit the cutting thickness of the section A to be cut, and the cutting thickness can reach nanometer level.
[0064] Exemplarily, after cutting the section to be cut to obtain a target cutting section, the method further includes:
[0065] The adjacent to-be-cut surface of the target cutting section is cut. That is, after the target cutting section is obtained, the adjacent area of the target cutting section can also be observed in a large area.
[0066] Wherein, cutting the adjacent to-be-cut surface of the target cutting section comprises:
[0067] First, the edge point of the target cutting section is centered between the sample stage and the second surface of the baffle along the second direction, and the adjacent to-be-cut surface is flush with the plane where the highest point of the baffle is located.
[0068] Specifically, the semiconductor device 110 after cross-section cutting is fixed by a high-precision sample loader. The process of fixing the semiconductor device 110 can refer to step S130. Figure 7 As shown in b, the edge point F of the target cutting section d is centered in the X-axis direction, and the adjacent to-be-cut surface is flush with the plane where the highest point of the baffle 120 is located.
[0069] Secondly, the first surface of the baffle is again subjected to argon ion cutting with the preset cutting parameters by using argon ion cross-section polishing to cut the adjacent to-be-cut surfaces to obtain adjacent target cutting cross-sections.
[0070] Specifically, the process of performing cross-section cutting on adjacent to-be-cut surfaces may refer to step S140 , wherein the adjacent to-be-cut surfaces are cross-section cut using the same preset cutting parameters as in step S140 to obtain adjacent target cutting cross-sections.
[0071] Fig.10 To use the cross-section cutting method S100 of the embodiment of the present disclosure to perform secondary cutting on the adjacent area of the target cutting cross-section to obtain the cutting cross-section, Fig.10 It can be seen that the target cutting section that is cut twice and the section of the cutting overlapping area between adjacent target cutting sections are still in the position to be observed and have not been cut off, and other points to be observed at adjacent positions have also been well sectioned, which can achieve large-area cutting of continuous areas.
[0072] Exemplarily, after cutting the section to be cut to obtain a target cutting section, the method further includes:
[0073] A scanning electron microscope is used to perform high-magnification observation of the interface between different materials on the target cutting section.
[0074] Specifically, Fig. 9 The overall image of the target cutting section and the enlarged image of the bonding surface taken with an electron microscope are Fig. 9 It can be known that after the semiconductor device is cut by the cross-section cutting method S100 according to the embodiment of the present disclosure, the target cutting cross section A has no stress deformation and a clear bonding surface. Fig.10 This is a picture of the entire cut section taken with an electron microscope after secondary processing of the adjacent area of the cut section. Fig.10 It can be seen that the target cutting section that is cut twice and the section of the cutting overlapping area between the adjacent target cutting sections are still in the position to be observed and have not been cut off, and other points to be observed at adjacent positions have also been well sectioned.
[0075] The semiconductor device cross-section cutting method of the disclosed embodiment first manually grinds the semiconductor device to the cross-section to be cut to achieve precise positioning, and then performs argon ion cross-section polishing to achieve nano-scale cutting of the cross-section to be cut. The process steps are simple and the stress caused by manual grinding is completely eliminated to better observe the bonding between different materials inside the semiconductor device. The adjacent area of the target cutting cross-section can be cut a second time. Because the thickness of a single cut is small, even if the adjacent area is cut a second time, the cutting thickness of the overlapping area is also very small, and the position that needs to be observed will not be cut through, thereby achieving large-scale cutting of continuous areas. When polishing the same cross-sectional area, the cutting time is greatly reduced (from 30 minutes to 5 minutes), saving time.
[0076] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the embodiments of the present disclosure, but the embodiments of the present disclosure are not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the embodiments of the present disclosure, and these modifications and improvements are also considered to be within the protection scope of the embodiments of the present disclosure.
Claims
1. A semiconductor device cross-section cutting method, characterized in that: The method comprises: A semiconductor device, a baffle and a sample stage are provided, wherein the semiconductor device is made of a plurality of different materials, the baffle has a first surface and a second surface arranged opposite to each other, and the height of the first surface is higher than the height of the second surface; Manually grinding the semiconductor device along a first direction directly to a cross section to be cut; Fix the semiconductor device between the sample stage and the second surface of the baffle, wherein the first surface of the baffle is arranged away from the sample stage, and adjust the positions of the baffle and the semiconductor device so that the section to be cut is exposed and located in the center in the second direction, and the section to be cut is flush with the plane where the highest point of the baffle is located; The first surface of the baffle is subjected to argon ion cutting with preset cutting parameters by using an argon ion cross-section polishing method, so as to cut the cross section to be cut to obtain a target cutting cross section.
2. The method according to claim 1, characterized in that The cutting thickness of the cross section to be cut is the difference between the height of the first surface of the baffle and the height of the second surface thereof.
3. The method according to claim 1, characterized in that The preset cutting parameters include: eccentricity is 0, acceleration voltage range is 2KV~8KV, gas flow range is 0.07cm 3 / min~0.1cm 3 / min, and the cross-section grinding time ranges from 4min to 6min.
4. The method according to claim 3, characterized in that The method of using argon ion cross-section polishing to perform argon ion cutting on the first surface of the baffle with preset cutting parameters to cut the cross section to be cut to obtain a target cutting cross section includes: The semiconductor device fixed in position is placed in an ion polisher, an argon ion cross-section polishing mode is selected, and the first surface of the baffle is bombarded with argon ions with the preset cutting parameters to complete the cutting of the baffle; After the baffle is cut, the section to be cut is bombarded with argon ions to obtain the target cutting section.
5. The method according to any one of claims 1 to 3, characterized in that: After the section to be cut is cut to obtain a target cutting section, the method further includes: Cutting is performed on the adjacent to-be-cut surface of the target cutting section.
6. The method according to claim 5, characterized in that The step of cutting the adjacent to-be-cut surface of the target cutting section comprises: Centering the edge point of the target cutting section along the second direction between the sample stage and the second surface of the baffle, and aligning the adjacent to-be-cut surface with the plane where the highest point of the baffle is located; The first surface of the baffle is again subjected to argon ion cutting with the preset cutting parameters by using argon ion cross-section polishing to cut the adjacent to-be-cut surfaces to obtain adjacent target cutting cross-sections.
7. The method according to claim 6, characterized in that The target cutting section and the section of the cutting overlapping area between the adjacent target cutting sections are still in the position to be observed.
8. The method according to any one of claims 1 to 3, characterized in that: After the section to be cut is cut to obtain a target cutting section, the method further includes: A scanning electron microscope is used to perform high-magnification observation of the interface between different materials on the target cutting section.
9. The method according to any one of claims 1 to 3, characterized in that: The method of directly grinding the semiconductor device along the first direction to the cross section to be cut by manual grinding includes: The semiconductor device is directly ground to the section to be cut along the first direction by using a grinder, sandpaper with different meshes, a polishing cloth and a polishing liquid; wherein the mesh of the sandpaper ranges from 80 meshes to 4000 meshes.
10. The method according to any one of claims 1 to 3, characterized in that: When the semiconductor device is fixed between the sample stage and the second surface of the baffle, the height of the sample stage is lower than the height of the cross section to be cut.