A three-dimensional cross-sectional sample of a packaged chip and a preparation method thereof

Abstract

The present invention discloses a three-dimensional cross-sectional sample of a packaged chip and a preparation method thereof. The three-dimensional cross-sectional sample preparation method comprises: scanning and analyzing the packaged chip to be tested to determine whether the packaged chip to be tested has an abnormal area; if so, determining a grinding position according to the setting position of the abnormal area to grind and polish the packaged chip to be tested to obtain a first cross-sectional sample; using a focused ion beam to perform ion beam etching of a preset thickness on the target analysis area of the first cross-sectional sample to form a detection space inside the packaged chip to prepare a three-dimensional cross-sectional sample; the target analysis area includes the abnormal area. A three-dimensional cross-sectional sample can be obtained by the above-mentioned three-dimensional cross-sectional sample preparation method, and the three-dimensional cross-sectional sample can be unaffected by grinding, which is conducive to the accurate analysis of microcrack defects in the packaged chip.

Description

Technical Field

[0001] The present invention relates to the field of chip technology, and in particular to a three-dimensional cross-section sample of a packaged chip and a preparation method thereof. Background Art

[0002] Current semiconductor chip sizes have reached 7-5nm, or even 3-2nm, and wafer manufacturing processes are gradually approaching their limits. Therefore, chip packaging technology has become a major future development direction. Existing advanced packaging technology is chiplet packaging. This advanced packaging technology can stack multiple chips with different functions, sizes, and process steps, increasing capacity many times that of traditional chips. It can also combine various chip types to form a more optimized system through advanced packaging. However, the application of this advanced packaging technology requires more advanced failure analysis technology to support it.

[0003] As we all know, poor chip packaging quality can leave microcracks between the packaging material layer and the chip surface, leading to poor contact, failure, and low reliability. Later, there's also the potential for moisture intrusion through these microcracks. To detect these packaging issues, a scanning microscope can be used to scan package samples for cracks and other abnormalities.

[0004] In order to further observe and analyze the actual situation of the microcrack defect area, we usually need to prepare high-quality cross-sectional samples for further analysis. However, since the distribution of these microcrack defects is random and uneven, the cross-sectional samples prepared only by grinding methods cannot reveal the true situation of these microcrack defects. In addition, during the grinding process, the original microcrack defects will be damaged or pushed. Some microcrack defects will even be filled with grinding materials or products and disappear. In order to obtain the true situation of microcrack defects, we can use focused ion beam (FIB) to directly prepare cross-sectional samples. However, due to the large area and volume of chips packaged using core particle packaging technology, it is unrealistic to directly use focused ion beam (FIB) to prepare cross-sectional samples. It will be very time-consuming and sometimes impossible to do.

[0005] Therefore, the most commonly used method for preparing cross-sectional samples is still grinding, but the final result is only a matter of luck. Some cross-sectional samples can be used for microcrack defect analysis, while some cross-sectional samples cannot. Summary of the Invention

[0006] The present invention provides a three-dimensional cross-sectional sample of a packaged chip and a preparation method thereof, so as to solve the problem that the cross-sectional sample of the existing packaged chip is damaged due to grinding and cannot be used for microcrack defect analysis.

[0007] In a first aspect, an embodiment of the present invention provides a method for preparing a three-dimensional cross-sectional sample of a packaged chip, the method comprising:

[0008] Scan and analyze the packaged chip to be tested to determine whether there is an abnormal area in the packaged chip to be tested;

[0009] If yes, determining a grinding position according to the setting position of the abnormal area to grind and polish the packaged chip to be tested to obtain a first cross-section sample;

[0010] A focused ion beam is used to perform ion beam etching of a preset thickness on the target analysis area of the first cross-sectional sample to form a detection space inside the packaged chip to be tested, thereby preparing a three-dimensional cross-sectional sample; the target analysis area includes the abnormal area.

[0011] Optionally, using a focused ion beam to perform ion beam etching of a preset thickness on a preset area of the first cross-section sample to form a detection space inside the packaged chip to be tested, comprising:

[0012] Depositing a conductive layer on the surface of the target analysis area;

[0013] Ion beam cutting is performed on the target analysis area, and the direction in which the ion beam is emitted intersects with the cross section of the first cross section sample.

[0014] Optionally, the direction in which the ion beam is emitted is perpendicular to the cross section of the first cross section sample.

[0015] Optionally, it is characterized in that a focused ion beam is used to perform ion beam etching of a preset thickness on a target analysis area of the first cross-section sample to form a detection space inside the packaged chip to be tested, comprising:

[0016] A first beam ion beam is used to perform a first ion beam etching of a preset thickness on the target analysis area of the first cross-section sample to form a preliminary detection space inside the packaged chip to be tested; a second beam ion beam is used to perform a second ion beam etching on the preliminary detection space to form the detection space; the beam size of the second beam ion beam is smaller than the beam size of the first beam ion beam.

[0017] Optionally, scan and analyze the packaged chip to be tested, including:

[0018] Placing the packaged chip to be tested into a deionized water tank;

[0019] The packaged chip to be tested is scanned and analyzed using an ultrasonic reflection scanning mode and an ultrasonic transmission scanning mode respectively.

[0020] Optionally, determining a grinding position according to a setting position of the abnormal area to grind and polish the packaged chip to be tested includes:

[0021] Performing sealing on the packaged chip to be tested;

[0022] The packaged chip to be tested after the sealant is subjected to a first grinding process, a second grinding process, and a third grinding process in sequence; the mesh number of the grinding sandpaper in the first grinding process is smaller than the mesh number of the grinding sandpaper in the second grinding process, and the mesh number of the grinding sandpaper in the second grinding process is smaller than the mesh number of the grinding sandpaper in the third grinding process;

[0023] The packaged chip to be tested is polished.

[0024] Optionally, sealing the packaged chip to be tested with glue includes:

[0025] Covering the packaged chip to be tested with glue and curing the glue, wherein the glue comprises epoxy resin and epoxy curing agent;

[0026] Polishing the packaged chip to be tested, comprising:

[0027] The packaged chip to be tested is polished with a polishing cloth or ion beam polished.

[0028] Optionally, after forming the detection space inside the packaged chip, the method further includes:

[0029] The detection space is scanned and analyzed by a scanning electron microscope.

[0030] Optionally, after forming the detection space inside the packaged chip, the method further includes:

[0031] An energy spectrum analysis is performed on the detection space by using an energy spectrometer.

[0032] In a second aspect, an embodiment of the present invention provides a three-dimensional cross-sectional sample of a packaged chip, which is prepared using the three-dimensional cross-sectional sample preparation method described in any embodiment of the first aspect;

[0033] The three-dimensional cross-sectional sample includes a detection space located inside the packaged chip.

[0034] The technical solution of an embodiment of the present invention provides a method for preparing a three-dimensional cross-sectional sample of a packaged chip, the method comprising: scanning and analyzing the packaged chip to be tested to determine whether there is an abnormal area in the packaged chip to be tested; if so, determining a grinding position based on the setting position of the abnormal area to grind and polish the packaged chip to be tested to obtain a first cross-sectional sample; using a focused ion beam to perform ion beam etching of a preset thickness on the target analysis area of the first cross-sectional sample to form a detection space inside the packaged chip to prepare a three-dimensional cross-sectional sample, wherein the target analysis area includes the abnormal area. The present invention can obtain a three-dimensional cross-sectional sample through the above-mentioned three-dimensional cross-sectional sample preparation method, and the three-dimensional cross-sectional sample can be unaffected by grinding, thereby solving the problem that the cross-sectional samples of existing packaged chips are damaged due to grinding and cannot be used for microcrack defect analysis, and is conducive to achieving accurate analysis of microcrack defects in packaged chips.

[0035] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A flow chart of a method for preparing a three-dimensional cross-section sample of a packaged chip provided in an embodiment of the present invention;

[0038] Figure 2 A flow chart of another method for preparing a three-dimensional cross-section sample of a packaged chip provided by an embodiment of the present invention;

[0039] Figure 3 A scanning electron microscope image of a first cross-section sample provided by an embodiment of the present invention;

[0040] Figure 4 A scanning electron microscope image of a three-section sample provided by an embodiment of the present invention;

[0041] Figure 5 A flow chart of another method for preparing a three-dimensional cross-section sample of a packaged chip provided in an embodiment of the present invention;

[0042] Figure 6 A flow chart of another method for preparing a three-dimensional cross-section sample of a packaged chip provided in an embodiment of the present invention;

[0043] Figure 7 A scanning electron microscope image of a detection space provided by an embodiment of the present invention;

[0044] Figure 8 This is a scanning electron microscope image of the interior of a detection space provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0046] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0047] Example 1

[0048] Figure 1 A flowchart of a method for preparing a three-dimensional cross-section sample of a packaged chip provided in an embodiment of the present invention, with reference to Figure 1 The three-dimensional cross-section sample preparation method in the embodiment of the present invention includes:

[0049] S110 , scanning and analyzing the packaged chip to be tested to determine whether there is an abnormal area in the packaged chip to be tested.

[0050] For example, the packaged chip to be tested is scanned and analyzed by an ultrasonic scanning microscope, and then it can be determined whether there is an abnormal area in the packaged chip to be tested based on the scanning and analysis results.

[0051] S120: If yes, determine a grinding position according to the setting position of the abnormal area to grind and polish the packaged chip to be tested to obtain a first cross-section sample.

[0052] For example, after determining that there is an abnormal area in the packaged chip to be tested and determining the grinding position according to the setting position of the abnormal area, the packaged chip to be tested can be ground and polished to expose the abnormal area and obtain a first cross-sectional sample that can show the abnormal area.

[0053] S130: Using a focused ion beam, ion beam etching is performed on a target analysis region of the first cross-sectional sample to a preset thickness to form a detection space inside the packaged chip, thereby preparing a three-dimensional cross-sectional sample. The target analysis region includes the abnormal region.

[0054] For example, after obtaining a first cross-sectional sample that reveals an abnormal region, a target analysis region to be inspected and analyzed can be selected based on the abnormal region within the first cross-sectional sample. A focused ion beam is then used to ion-beam etch the target analysis region of the first cross-sectional sample to a predetermined thickness, thereby forming a detection space within the packaged chip and obtaining a three-dimensional cross-sectional sample. Once the three-dimensional cross-sectional sample, including the detection space, is obtained, the interior of the detection space can be inspected and analyzed, thereby enabling accurate analysis of microcrack defects in the packaged chip.

[0055] It should be noted that the embodiment of the present invention does not limit the numerical value of the above-mentioned preset thickness, and those skilled in the art can set it according to actual needs.

[0056] The embodiment of the present invention can obtain a three-dimensional cross-sectional sample including a detection space through the above-mentioned three-dimensional cross-sectional sample preparation method, and can achieve accurate analysis of microcrack defects in the packaged chip by detecting and analyzing the inside of the detection space. Therefore, the detection and analysis of the three-dimensional cross-sectional sample of the packaged chip in the embodiment of the present invention will not be affected by grinding, which solves the problem that the cross-sectional samples of the existing packaged chips will be damaged due to grinding and cannot be used for microcrack defect analysis.

[0057] Based on the above embodiments, Figure 2 A flow chart of another method for preparing a three-dimensional cross-section sample of a packaged chip provided by an embodiment of the present invention. Figure 2 In the embodiment shown, a detailed description is given of how to use a focused ion beam to perform ion beam etching of a preset thickness on a preset area of the first cross-section sample to form a detection space inside the packaged chip. Figure 2 , the three-dimensional cross-section sample preparation method in this embodiment includes:

[0058] S210 , scanning and analyzing the packaged chip to be tested to determine whether there is an abnormal area in the packaged chip to be tested.

[0059] As a feasible implementation method, scanning and analyzing the packaged chip to be tested includes: placing the packaged chip to be tested in a deionized water tank, and scanning and analyzing the packaged chip to be tested using an ultrasonic reflection scanning mode and an ultrasonic transmission scanning mode respectively.

[0060] For example, ultrasonic reflection scanning analysis and ultrasonic transmission scanning analysis are performed on the packaged chip to be tested through an ultrasonic scanning microscope. Ultrasonic reflection scanning has a higher resolution than transmission scanning. Although ultrasonic transmission scanning has a lower resolution than reflection scanning, ultrasonic transmission scanning can penetrate the entire packaged chip to be tested. Combining it with reflection scanning for judgment can more accurately determine whether there are abnormal areas in the packaged chip to be tested, as well as the location of the abnormal areas, to avoid misjudgment.

[0061] S220: If yes, determine a grinding position according to the setting position of the abnormal area to grind and polish the packaged chip to be tested to obtain a first cross-section sample.

[0062] As a feasible embodiment, determining a grinding position based on the location of the abnormal region to grind and polish the packaged chip under test includes: sealing the packaged chip under test with glue, and sequentially performing a first grinding step, a second grinding step, and a third grinding step on the sealed packaged chip under test. The mesh size of the grinding sandpaper in the first grinding step is smaller than the mesh size of the grinding sandpaper in the second grinding step, and the mesh size of the grinding sandpaper in the second grinding step is smaller than the mesh size of the grinding sandpaper in the third grinding step. The packaged chip under test is polished.

[0063] Furthermore, sealing the packaged chip under test with glue includes: covering the packaged chip under test with glue and curing the glue, wherein the glue includes epoxy resin and epoxy curing agent. Polishing the packaged chip under test includes: polishing the packaged chip under test with a polishing cloth or ion beam polishing.

[0064] For example, epoxy resin and epoxy curing agent are first adjusted in a suitable proportion, poured into the cup along the wall of the cup, and stirred evenly to obtain glue, and then the base is sealed on the glass sheet where the packaged chip to be tested is placed. Finally, the packaged chip to be tested is placed on the base, covered with glue, and cured. In this way, the smaller packaged chip to be tested can be turned into a larger sample, which is convenient for subsequent grinding.

[0065] The first grinding process includes: first, rinse the grinding and polishing machine disc with clean water to keep the disc clean and free of any protruding foreign matter, take 180-mesh sandpaper and install it on the disc and remove the bubbles at the bottom of the sandpaper, then turn on the grinding and polishing machine and adjust its speed to 200-400r / min, and finally turn on the cooling water. Use a microscope to observe the grinding position and start grinding. When the distance from the grinding position is about 5mm, observe whether the grinding surface is flat. If it is not flat, make corrections. When the distance from the grinding position is within 0.5mm, observe whether the grinding surface meets the flatness requirements of fine grinding. If not, it needs to be adjusted at 2500 mesh. It should be noted that for small samples, the position should be constantly observed under a microscope and 1200-mesh sandpaper should be used until it is ground to within 0.5mm. Grinding and positioning of larger samples is more convenient and quick, facilitating subsequent targeted analysis.

[0066] The second grinding process includes: first, rinse the grinding and polishing machine disc with clean water to keep the disc clean and free of any protruding foreign matter, take 1200 grit sandpaper and install it on the disc and remove the air bubbles at the bottom of the sandpaper, then turn on the grinding and polishing machine and adjust its speed to 200-400r / min, and finally turn on the cooling water. Observe the grinding position with a microscope to determine whether the grinding surface is tilted, and make corresponding adjustments during grinding. Always observe the grinding position during grinding and do not press hard. This process is to eliminate the deep scratches left by the first grinding process. It should be noted that when grinding, always observe the grinding position with a microscope to see if it has been reached. The second grinding process should be stopped after the grinding position has been reached.

[0067] The third grinding process includes: first rinse the grinding and polishing machine disc with clean water to keep the disc clean and free of any protruding foreign matter, take 2400 grit sandpaper and install it on the disc surface and remove the bubbles at the bottom of the sandpaper, then turn on the grinding and polishing machine and adjust its speed to 200-400r / min, and finally turn on the cooling water to start grinding. During grinding, always observe whether there are any residual scratches on the surface of the grinding position until the surface of the grinding position is observed to be free of scratches.

[0068] Polishing the packaged chip to be tested with a polishing cloth includes: first rinsing the disk surface and the grinding position surface with clean water to keep the disk surface and the grinding position surface clean and free of any protruding foreign matter, taking the polishing cloth and installing it on the disk surface and removing the bubbles at the bottom of the polishing cloth, then squeezing the polishing liquid on the center of the disk surface, and turning on the grinder and polisher and adjusting its speed to below 300r / min, finally turning on the cooling water to start polishing. Do not press hard, only use both hands to control the direction, adjust the polishing time according to the polishing effect, polish lightly along the edge, change a direction every 180 degrees, and adjust the polishing time according to the polishing effect until it meets the requirements of microscope observation and subsequent analysis needs.

[0069] Through the above-mentioned first grinding process, second grinding process, third grinding process and ion beam polishing, a first cross-section sample without surface scratches can be obtained. Figure 3 As shown, Figure 3 This is a scanning electron microscope image of a first cross-section sample provided in an embodiment of the present invention.

[0070] S230, depositing a conductive layer on the surface of the target analysis area.

[0071] Before the target analysis area of the first cross-section sample is ion beam cut by the ion beam cutting instrument, a conductive layer must be deposited on the surface of the target analysis area. The conductive layer is used to make the target analysis area conductive so that the scanning electron microscope can observe the cutting situation in real time when the ion beam cutting instrument performs ion beam cutting on the target analysis area, which is beneficial to improving the accuracy of ion beam cutting.

[0072] S240, performing ion beam cutting on the target analysis area, wherein the direction of ion beam emission intersects with the cross section of the first cross section sample.

[0073] As a feasible implementation manner, the direction in which the ion beam is emitted is perpendicular to the cross section of the first cross section sample.

[0074] For example, when performing ion beam cutting on the target analysis area, the direction of ion beam emission should be controlled to intersect with the cross section of the first cross section sample, so that a detection space can be formed inside the packaged chip to prepare a three-dimensional cross section sample. Preferably, the direction of ion beam emission can be set to be perpendicular to the cross section of the first cross section sample, so that the detection space formed is more convenient for detection and analysis. The three-dimensional cross section sample obtained by steps S230 and S240 is as follows: Figure 4 As shown, Figure 4 This is a scanning electron microscope image of a three-section sample provided in an embodiment of the present invention.

[0075] Based on the above embodiments, Figure 5 A flowchart of another method for preparing a three-dimensional cross-section sample of a packaged chip provided in an embodiment of the present invention. Figure 5 In the embodiment shown, a detailed description is given of how to use a focused ion beam to perform ion beam etching of a preset thickness on a preset area of the first cross-section sample to form a detection space inside the packaged chip. Figure 5 , the three-dimensional cross-section sample preparation method in this embodiment includes:

[0076] S310 , scanning and analyzing the packaged chip to be tested to determine whether there is an abnormal area in the packaged chip to be tested.

[0077] S320: If yes, determine a grinding position according to the setting position of the abnormal area to grind and polish the packaged chip to be tested to obtain a first cross-section sample.

[0078] S330, using a first beam ion beam to perform a first ion beam etching of a preset thickness on the target analysis area of the first cross-section sample to form a preliminary detection space inside the packaged chip.

[0079] S340, using a second beam ion beam to perform a second ion beam etching on the preliminary detection space to form a detection space, wherein the beam size of the second beam ion beam is smaller than the beam size of the first beam ion beam.

[0080] For example, a first ion beam with a larger size is used to perform a first ion beam etching of a preset thickness on the target analysis area of the first cross-section sample, which can quickly form a preliminary detection space inside the packaged chip. However, the surface of the preliminary detection space is relatively rough and uneven. A second ion beam with a smaller size can be used to perform a second ion beam etching on the preliminary detection space to fine-tune the surface of the preliminary detection space, thereby obtaining a detection space with a flat and smooth surface, which is convenient for subsequent detection and analysis.

[0081] Based on the above embodiments, Figure 6 A flowchart of another method for preparing a three-dimensional cross-section sample of a packaged chip provided in an embodiment of the present invention. Figure 6 The embodiment shown enriches the process of the three-dimensional cross-section sample preparation method, refer to Figure 6 , the three-dimensional cross-section sample preparation method in this embodiment includes:

[0082] S410 , scanning and analyzing the packaged chip to be tested to determine whether there is an abnormal area in the packaged chip to be tested.

[0083] S420: If yes, determine a grinding position according to the setting position of the abnormal area to grind and polish the packaged chip to be tested to obtain a first cross-section sample.

[0084] S430: Using a focused ion beam, ion beam etching is performed on a target analysis region of the first cross-sectional sample to a preset thickness to form a detection space inside the packaged chip, thereby preparing a three-dimensional cross-sectional sample. The target analysis region includes the abnormal region.

[0085] S440. Scan and analyze the detection space using a scanning electron microscope.

[0086] S450. Perform energy spectrum analysis on the detection space through an energy spectrometer.

[0087] For example, after obtaining a three-dimensional cross-sectional sample including the detection space, the detection space can be scanned and analyzed using a scanning electron microscope to observe whether there are any abnormalities in the target analysis area. An energy spectrometer can also be used to perform energy spectrum analysis on the detection space to determine whether there are any abnormal elements.

[0088] Figure 7A scanning electron microscope image of a detection space provided by an embodiment of the present invention, Figure 8 This is a scanning electron microscope image of the interior of a detection space provided by an embodiment of the present invention. Figure 8 The scanning electron microscope image of the interior of the detection space shown is Figure 7 The actual situation on the right side of the interior of the detection space is shown. Figure 7 The detection space shown is formed by ion beam cutting, and the previous grinding will not affect it, so the observation Figure 8 This enables accurate analysis of microcrack defects in packaged chips.

[0089] Example 2

[0090] An embodiment of the present invention provides a three-dimensional cross-sectional sample of a packaged chip. The three-dimensional cross-sectional sample is prepared using the three-dimensional cross-sectional sample preparation method described in the first embodiment.

[0091] The 3D cross-sectional sample includes the probe space located inside the packaged chip.

[0092] Compared with the two-dimensional cross-sectional samples obtained by grinding, the detection space in the three-dimensional cross-sectional samples obtained by grinding and ion beam cutting in the embodiment of the present invention can truly reflect the defect conditions of the packaged chip to be tested and is not affected by grinding, thereby solving the problem that the cross-sectional samples of existing packaged chips will be damaged due to grinding and cannot be used for microcrack defect analysis.

[0093] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for preparing a three-dimensional cross-section sample of a packaged chip, characterized in that: include: Scan and analyze the packaged chip to be tested to determine whether there is an abnormal area in the packaged chip to be tested; If yes, determining a grinding position according to the setting position of the abnormal area to grind and polish the packaged chip to be tested to obtain a first cross-section sample; Using a focused ion beam, ion beam etching of a preset thickness is performed on a target analysis area of the first cross-sectional sample to form a detection space inside the packaged chip to be tested, thereby preparing a three-dimensional cross-sectional sample, and then performing detection and analysis inside the detection space to achieve analysis of microcrack defects in the packaged chip; the target analysis area includes the abnormal area; Using a focused ion beam to perform ion beam etching of a preset thickness on a preset area of the first cross-section sample to form a detection space inside the packaged chip to be tested, comprising: Depositing a conductive layer on the surface of the target analysis area to make the target analysis area conductive; Performing ion beam cutting on the target analysis area, wherein the direction in which the ion beam is emitted intersects with the cross section of the first cross section sample, and the direction in which the ion beam is emitted is perpendicular to the cross section of the first cross section sample; Determining a grinding position according to the setting position of the abnormal area to grind and polish the packaged chip to be tested includes: Performing sealing on the packaged chip to be tested; The packaged chip to be tested after the sealant is subjected to a first grinding process, a second grinding process, and a third grinding process in sequence; the mesh number of the grinding sandpaper in the first grinding process is smaller than the mesh number of the grinding sandpaper in the second grinding process, and the mesh number of the grinding sandpaper in the second grinding process is smaller than the mesh number of the grinding sandpaper in the third grinding process; polishing the packaged chip to be tested; Sealing the packaged chip to be tested with glue, comprising: The packaged chip to be tested is covered with glue, and the glue is cured.

2. The method for preparing a three-dimensional cross-section sample according to claim 1, wherein: Using a focused ion beam to perform ion beam etching of a preset thickness on a target analysis area of the first cross-section sample to form a detection space inside the packaged chip to be tested, comprising: A first beam ion beam is used to perform a first ion beam etching of a preset thickness on the target analysis area of the first cross-section sample to form a preliminary detection space inside the packaged chip; a second beam ion beam is used to perform a second ion beam etching on the preliminary detection space to form the detection space; the beam size of the second beam ion beam is smaller than the beam size of the first beam ion beam.

3. The method for preparing a three-dimensional cross-section sample according to claim 1, wherein: Scan and analyze the packaged chip to be tested, including: Placing the packaged chip to be tested into a deionized water tank; The packaged chip to be tested is scanned and analyzed using an ultrasonic reflection scanning mode and an ultrasonic transmission scanning mode respectively.

4. The method for preparing a three-dimensional cross-section sample according to claim 1, wherein: The glue includes epoxy resin and epoxy curing agent; Polishing the packaged chip to be tested, comprising: The packaged chip to be tested is polished with a polishing cloth or ion beam polished.

5. The method for preparing a three-dimensional cross-section sample according to claim 1, wherein: After forming the detection space inside the packaged chip, the method further includes: The detection space is scanned and analyzed by a scanning electron microscope.

6. The method for preparing a three-dimensional cross-section sample according to claim 1, wherein: After forming the detection space inside the packaged chip, the method further includes: An energy spectrum analysis is performed on the detection space by using an energy spectrometer.

7. A three-dimensional cross-sectional sample of a packaged chip, characterized in that: Prepared by the three-dimensional cross-section sample preparation method according to any one of claims 1 to 6; The three-dimensional cross-sectional sample includes a detection space located inside the packaged chip.

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