A tem sample, its preparation method and application

Abstract

This invention provides a TEM sample, its preparation method, and its application. The TEM sample preparation method provided by this invention, without affecting the pore structure of the semiconductor device, first uses reactive ion etching to remove some residual polymer deposits blocking the pore openings on the semiconductor device. This enlarges the pore openings, preventing blockage and facilitating the entry of colloidal materials into the pore structure for filling and the deposition of precursor materials for atomic layer deposition. This enhances the clarity of the pore sidewalls, effectively improving the quality of the TEM sample and the final observation results. Furthermore, the TEM sample preparation method provided by this invention requires less equipment and technical investment, and the operation process is simpler and faster than Fab etching. It also enables batch laboratory-scale sample processing. In addition, compared to wet chemical etching cleaning techniques for removing residual polymers, it avoids problems such as chemical reagent residues at the bottom of deep pore structures and chemical reactant contamination.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a TEM sample, its preparation method, and its application. Background Technology

[0002] As the size of semiconductor integrated circuits continues to shrink, transmission electron microscopy (TEM) is increasingly being used for device structure morphology characterization and failure analysis. Among these, the quality of TEM samples prepared using focused ion beam (FIB) directly affects the observation results of TEM.

[0003] Existing processes typically employ C during the etching of insulating or dielectric layers (primarily composed of SiO2 or Si3N4, etc.) in semiconductor devices to form vias. x F y The compound, under the action of a high-frequency electric field, forms a plasma that etches the dielectric layer. At the same time, it reacts to generate residual polymers containing hydrocarbon and fluorine components, which are deposited on the sidewall surface of the etched interface to form passivation. The longer the etching time, the more it accumulates, and it can even form a very thick accumulation layer at the opening of the etched hole, causing the hole to be blocked. This is more likely to occur in holes with high aspect ratio.

[0004] The phenomenon of residual polymer accumulating and blocking the orifice during TEM sample preparation and pretreatment prevents the precursor material of atomic layer deposition (ALD) from entering the via and depositing on the inner sidewall, resulting in unclear observation of the via sidewall by the final TEM. At the same time, it also prevents the protective colloid from entering the via to fill it, causing ion beam scratches due to voids in the sample during focused ion beam (FIB) preparation, which in turn affects the TEM imaging quality and may even damage the TEM sample in severe cases, making it unanalyzable.

[0005] Existing methods for removing residual polymers after etching mainly utilize chemical etching cleaning, using strong solvents to clean the wafer and remove the residual polymers. CN1665755A discloses a composition for selectively removing residual polymers after etching. This composition contains deionized water, organic dicarboxylic acid, organic or inorganic alkali, fluoride-containing compounds, and corrosion inhibitors, which can remove residual polymers after etching. However, this method involves more than eight components, resulting in high costs; moreover, the composition formulation is complex, especially requiring strict control of the final pH value of the composition, which is difficult to implement.

[0006] Current chemical etching cleaning methods often fail to completely remove residual polymers, leaving behind some insoluble polymer particles. Furthermore, the complex formulation of cleaning solutions makes it difficult to precisely control the degree of removal of residual polymers, which can easily lead to damage to the film structure of the sample after the residual polymers are removed, thus affecting the accuracy of TEM characterization of the sample structure and size.

[0007] Therefore, it is necessary to design a method for preparing TEM samples that can effectively improve the quality of TEM sample preparation and the final observation results. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a TEM sample, its preparation method, and its application. By designing the process steps, the technical problem of residual polymers on the surface formed by the etched hole structure affecting the TEM sample preparation effect is solved, resulting in high-quality TEM samples and thus improving the observation effect of semiconductor devices.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a method for preparing a TEM sample, the method comprising the following steps:

[0011] (1) A semiconductor device containing a hole structure is provided; the hole structure is formed by etching the semiconductor device with a plasma of fluorocarbon gas; a residual polymer formed during the etching process is deposited at the opening of the hole on the surface of the semiconductor device;

[0012] Without affecting the pore structure, the residual polymer at the pore opening is removed by reactive ion etching using plasma of oxygen and carrier gas, thereby enlarging the pore opening.

[0013] (2) Mark the target region containing the hole structure on the semiconductor device;

[0014] (3) Apply a protective colloid to the surface of the target area to form a protective layer;

[0015] (4) The target region is separated from the body of the semiconductor device using a first focused ion beam to obtain a first sample;

[0016] (5) The first sample is thinned using a second focused ion beam to obtain the TEM sample.

[0017] The TEM sample preparation method provided by this invention first uses reactive ion etching (RIE) to remove some residual polymer deposits blocking the orifices of semiconductor devices, thereby enlarging the openings of the pore structure and preventing blockage. This facilitates the entry of colloids into the pore structure for filling and enhances the structural contour information within the pores. Simultaneously, some residual polymer is retained to protect the sample structure from plasma etching damage. This method effectively improves the quality of TEM samples and the final observation results. The TEM sample preparation method provided by this invention requires less equipment and technical investment, and the operation process is simpler and faster than Fab etching processes. It also enables batch laboratory-scale sample processing. Furthermore, compared to wet chemical etching cleaning techniques, it avoids problems such as chemical reagent residues at the bottom of deep-hole structures and chemical reactant contamination.

[0018] In this invention, the residual polymer includes hydrocarbon and fluorocarbon components. The oxygen plasma can chemically react with the hydrocarbon components in the residual polymer, and the oxygen ions and carrier gas can physically bombard the residual polymer. Through the combination of chemical reaction and physical bombardment effect, the covalent bonds between residual polymer molecules can be broken, promoting the removal of residual polymer and achieving mild and precise controllable plasma etching cleaning.

[0019] In this invention, the semiconductor device containing a hole structure includes a substrate and a dielectric layer disposed on the substrate. The hole structure is formed by etching the dielectric layer with a plasma of fluorocarbon gas. The material of the dielectric layer includes, but is not limited to, SiO2 or Si3N4.

[0020] This invention does not limit the amount of residual polymer removed from the orifice; as long as the orifice is enlarged so that the protective colloid can enter the pore structure and fill it, it is acceptable.

[0021] In this invention, the marking method in step (2) includes laser marking.

[0022] In this invention, the target region may contain only one hole structure or multiple (at least two) hole structures.

[0023] In this invention, after the protective colloid is coated on the surface of the target area in step (3), due to gravity, part of the protective colloid will enter the pore structure and fill it, while the other part of the protective colloid will adhere to the surface of the target area to form a protective layer.

[0024] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0025] As a preferred technical solution, the diameter of the hole structure is 10-70nm (e.g., it can be 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, etc.), and the depth is 50-3000nm (e.g., it can be 100nm, 200nm, 400nm, 600nm, 1000nm, 1200nm, 1400nm, 1600nm, 1800nm, 2000nm, 2200nm, 2400nm, 2600nm, 2800nm, etc.).

[0026] Preferably, the general chemical formula of the fluorocarbon gas is C1. x F y or CH x F y .

[0027] Preferably, the fluorocarbon gas includes any one or a combination of at least two of CHF3, CH2F2, CH3F, or CF4.

[0028] Preferably, the carrier gas includes any one or a combination of at least two of helium, nitrogen, or argon.

[0029] Preferably, the chamber pressure for reactive ion etching is 5-100 mTorr, for example, it can be 10 mTorr, 12 mTorr, 14 mTorr, 16 mTorr, 18 mTorr, 20 mTorr, 22 mTorr, 24 mTorr, 26 mTorr, 28 mTorr, 30 mTorr, 40 mTorr, 50 mTorr, 60 mTorr, 70 mTorr, 80 mTorr, 90 mTorr, etc.

[0030] Preferably, the radio frequency power of the reactive ion etching is 10-50W, for example, it can be 12W, 15W, 18W, 20W, 22W, 25W, 28W, 30W, 32W, 35W, 38W, 40W, 42W, 45W, 48W, etc.

[0031] Preferably, the flow rates of oxygen and carrier gas in the reactive ion etching are each independently 10-100 mL / min, for example, 15 mL / min, 20 mL / min, 25 mL / min, 30 mL / min, 35 mL / min, 40 mL / min, 45 mL / min, 50 mL / min, 55 mL / min, 60 mL / min, 65 mL / min, 70 mL / min, 75 mL / min, 80 mL / min, 85 mL / min, 90 mL / min, 95 mL / min, etc.

[0032] Preferably, the flow rate ratio of oxygen to carrier gas in the reactive ion etching is (1-2):1, for example, it can be 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, etc.

[0033] Preferably, the reactive ion etching time is 5-60s, for example, it can be 10s, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s, etc.

[0034] In this invention, the flow rates of oxygen and carrier gas, as well as the etching time of reactive ions, can be adjusted according to the amount of residual polymer at the orifice to obtain an ideal etching effect.

[0035] Preferably, the gas generated during the reactive ion etching process is discharged through a gas extraction system to achieve the etching and cleaning effect.

[0036] Preferably, the marking process further includes an atomic layer deposition step on the pore walls of the pore structure.

[0037] Preferably, the thickness of the thin film formed by the atomic layer deposition is 1-10 nm, for example, it can be 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, 5.5 nm, 6 nm, 6.5 nm, 7 nm, 7.5 nm, 8 nm, 8.5 nm, 9 nm, 9.5 nm, etc.

[0038] Preferably, the precursor material for the atomic layer deposition includes tetrakis(dimethylamino)hafnium and / or trimethylaluminum.

[0039] Preferably, the deposition temperature of the atomic layer deposition is 40-80℃ (e.g., 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, etc.), the cavity pressure is 30-50 Torr (e.g., 32 Torr, 34 Torr, 36 Torr, 38 Torr, 40 Torr, 42 Torr, 44 Torr, 46 Torr, 48 Torr, etc.), and the flow rate of the precursor material is 5-20 sccm (e.g., 6 sccm, 7 sccm, 8 sccm, 9 sccm, 10 sccm, 11 sccm, 12 sccm, 13 sccm, 14 sccm, 15 sccm, 16 sccm, 17 sccm, 18 sccm, 19 sccm, etc.).

[0040] In this invention, atomic layer deposition is performed on the pore walls of the pore structure to enhance the outlining effect of the sample structure under TEM, which facilitates the observation of the pore contour morphology and the measurement of key dimensions.

[0041] Preferably, the protective colloid comprises epoxy resin adhesive.

[0042] In this invention, the epoxy resin adhesive includes, but is not limited to, the ion-thinning resin 610 from Beijing Haide Venture Biotechnology Co., Ltd.

[0043] Preferably, the thickness of the protective layer is 20-300nm, for example, it can be 40nm, 60nm, 80nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 220nm, 240nm, 260nm, 280nm, etc.

[0044] Preferably, the coating process further includes a heat treatment step.

[0045] Preferably, the heat treatment temperature is 50-100℃, for example, it can be 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, etc.

[0046] Preferably, the heat treatment time is 10-30 min, for example, it can be 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, etc.

[0047] Preferably, the beam current of the first focused ion beam is 90-9900 pA (e.g., 100 pA, 200 pA, 500 pA, 1000 pA, 1500 pA, 2000 pA, 2500 pA, 3000 pA, 3500 pA, 4000 pA, 4500 pA, 5000 pA, 5500 pA, 6000 pA, 6500 pA, 7000 pA, 7500 pA, 8000 pA, 8500 pA, 9000 pA, 9500 pA, etc.), and the voltage is 8-30 kV, for example, 10 kV, 12 kV, 14 kV, 16 kV, 18 kV, 20 kV, 22 kV, 24 kV, 26 kV, 28 kV, etc.

[0048] Preferably, the length of the first sample is 2-10 μm (e.g., it can be 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, etc.), the width is 3-5 μm (e.g., it can be 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4 μm, 4.2 μm, 4.4 μm, 4.6 μm, 4.8 μm, etc.), and the thickness is 1-2 μm (e.g., it can be 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, etc.).

[0049] Preferably, the beam current of the second focused ion beam is 41-260 pA, for example, it can be 50 pA, 60 pA, 80 pA, 100 pA, 120 pA, 140 pA, 160 pA, 180 pA, 200 pA, 220 pA, 240 pA, 260 pA, etc., and the voltage is 2-30 kV, for example, it can be 5 kV, 10 kV, 12 kV, 14 kV, 16 kV, 18 kV, 20 kV, 22 kV, 24 kV, 26 kV, 28 kV, etc.

[0050] Preferably, the thinning process is carried out to a sample thickness of 10-80 nm, for example, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, etc.

[0051] Preferably, the preparation method specifically includes the following steps:

[0052] (1) A semiconductor device containing a hole structure is provided; the hole structure is formed by etching the semiconductor device with plasma of fluorocarbon gas; residual polymer formed during the etching process is deposited at the opening of the hole on the surface of the semiconductor device; the diameter of the hole structure is 10-70 nm and the depth is 50-3000 nm.

[0053] Without affecting the hole structure, the residual polymer at the hole opening is subjected to reactive ion etching using plasma of oxygen and carrier gas to remove part of the residual polymer at the hole opening, thereby enlarging the hole opening. The gas generated during the reactive ion etching process is discharged through a vacuum system.

[0054] The chamber pressure for the reactive ion etching is 5-100 mTorr, the radio frequency power is 10-50 W, and the flow rates of oxygen and carrier gas are each 10-100 mL / min; the flow rate ratio of oxygen to carrier gas is (1-2):1; and the time for the reactive ion etching is 5-60 s.

[0055] (2) After atomic layer deposition on the pore walls of the pore structure to form a thin film with a thickness of 1-10 nm, the target area containing the pore structure is marked on the semiconductor device;

[0056] (3) Apply the protective colloid to the surface of the target area, and then heat treat it at 50-100℃ for 10-30 min to form a protective layer with a thickness of 20-300nm;

[0057] (4) The target region is separated from the body of the semiconductor device using a first focused ion beam with a beam current of 90-9900pA and a voltage of 8-30kV to obtain a first sample. The first sample has a length of 2-10μm, a width of 3-5μm, and a thickness of 1-2μm.

[0058] (5) The first sample is thinned to a thickness of 10-80 nm using a second focused ion beam with a current of 41-260 pA and a voltage of 2-30 kV to obtain the TEM sample.

[0059] Secondly, the present invention provides a TEM sample, which is prepared by the preparation method described in the first aspect.

[0060] Thirdly, the present invention provides a method for measuring the dimensions of a hole structure in a semiconductor device, the measurement method comprising:

[0061] The TEM sample as described in the second aspect was observed and the size of the pore structure in the semiconductor device was measured.

[0062] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] (1) The TEM sample preparation method provided by the present invention first uses reactive ion etching to remove some residual polymer that has accumulated and blocked the orifice on the semiconductor device, so that the orifice is no longer blocked, which is beneficial to protect the colloidal filling and effectively improves the quality of the TEM sample and the final observation effect.

[0065] (2) The TEM sample preparation method provided by the present invention requires less equipment and technology investment, and the operation process is simpler and faster than the Fab etching process; at the same time, it can also realize batch laboratory-scale sample processing; in addition, compared with wet chemical etching and cleaning technology, there will be no problems such as chemical reagent residues at the bottom of deep hole structures or chemical reactant contamination. Attached Figure Description

[0066] Figure 1 This is a schematic diagram showing that the openings on the surface of a semiconductor device are blocked by residual polymer.

[0067] Wherein, 1-substrate, 2-dielectric layer, 3-residual polymer;

[0068] Figure 2 This is a schematic diagram of the precursor material deposited after reactive ion etching and atomic layer deposition.

[0069] Wherein, 1-substrate, 2-dielectric layer, 3-residual polymer, 4-thin film formed after atomic layer deposition;

[0070] Figure 3 This is a TEM image of the TEM sample provided in Example 1;

[0071] Among them, 2-dielectric layer, 3-residual polymer, 4-thin film formed after atomic layer deposition;

[0072] Figure 4 The TEM image is of the TEM sample provided in Comparative Example 1;

[0073] Among them, 2-dielectric layer, 3-residual polymer, and 4-atom layer are thin films formed after deposition. Detailed Implementation

[0074] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0075] The sources of some components in the following examples and comparative examples are as follows:

[0076] Epoxy resin adhesive: Ion thinning resin 610 purchased from Beijing Haide Venture Biotechnology Co., Ltd.

[0077] Example 1

[0078] A TEM sample and its preparation method, the preparation method comprising the following steps:

[0079] (1) A semiconductor device containing a porous structure is provided, wherein the porous structure is formed by etching the semiconductor device with a plasma of fluorocarbon gas; the diameter of the porous structure is 30 nm and the depth is 1.5 μm, and residual polymer formed during the etching process is deposited at the opening of the porous structure on the surface of the semiconductor device, as shown in the schematic diagram. Figure 1 As shown, by Figure 1 It can be seen that the semiconductor device includes a substrate 1 and a dielectric layer 2, and the residual polymer 3 completely blocks the orifice;

[0080] The semiconductor device is placed in an etching chamber at a pressure of 10 mTorr, and oxygen and argon are introduced at a flow rate of 20 mL / min and 10 mL / min, respectively. A plasma of oxygen and argon is generated by glow discharge. Without affecting the hole structure, reactive ion etching is performed on the residual polymer at the hole opening. The radio frequency power is 15 W and the reactive ion etching time is 20 s to remove part of the residual polymer at the hole opening, thereby enlarging the hole opening.

[0081] (2) After reactive ion etching, the semiconductor device is removed, and hafnium oxide atomic layer deposition is performed on the pore walls of the pore structure. The deposition temperature is 50°C, the chamber pressure is 40.5 Torr, and the flow rate of the precursor material tetrakis(dimethylamino)hafnium is 10 sccm, forming a thin film with a thickness of 3 nm. A schematic diagram is shown below. Figure 2 As shown, by Figure 2 It can be seen that a uniform thin film is formed on the sidewall of the pore structure by atomic layer deposition 4;

[0082] The target region containing the hole structure is marked on the semiconductor device using a laser.

[0083] (3) The ion-thinning resin 610 is coated on the surface of the target area and then heat-treated at 50°C for 30 min to form a protective layer with a thickness of 200 nm.

[0084] (4) The target region is separated from the body of the semiconductor device using a focused ion beam with a current of 9.9 nA and a voltage of 30 kV to obtain a first sample. The first sample has a length of 3 μm, a width of 3 μm, and a thickness of 1.5 μm.

[0085] (5) The first sample was thinned to a thickness of 50 nm using a focused ion beam with a beam current of 260 pA and a voltage of 30 kV to obtain the TEM sample;

[0086] The TEM samples were tested using a FEI Talos F200E transmission electron microscope, and the test results are as follows: Figure 3 As shown, by Figure 3 It can be seen that the TEM sample preparation method provided by this invention can obtain high-quality TEM samples. After removing some residual polymer deposited and blocking the orifices on the semiconductor device by reactive ion etching, the precursor material of atomic layer deposition can enter the pore structure to form a film, enhancing the clarity of the pore sidewalls and improving the quality of the TEM sample and the final observation effect.

[0087] Example 2

[0088] A TEM sample and its preparation method are different from Example 1 only in that the operation of step (1) is as follows, while the other materials, process parameters and steps are the same as those in Example 1; after observing the TEM sample by transmission electron microscopy, a test image with the same effect as that in Example 1 can be obtained.

[0089] (1) Provide the same semiconductor device as in Example 1, place the semiconductor device in an etching chamber with a chamber pressure of 30 mTorr, introduce oxygen and argon gas with a flow rate of 10 mL / min and a flow rate of 10 mL / min; generate oxygen and argon plasma by glow discharge, and perform reactive ion etching on the residual polymer at the aperture without affecting the aperture structure, with a radio frequency power of 15 W and a reactive ion etching time of 60 s, to remove part of the residual polymer at the aperture and enlarge the aperture.

[0090] Example 3

[0091] A TEM sample and its preparation method are different from Example 1 only in that the operation of step (1) is as follows, while the other materials, process parameters and steps are the same as those in Example 1; after observing the TEM sample by transmission electron microscopy, a test image with the same effect as that in Example 1 can be obtained.

[0092] (1) Provide the same semiconductor device as in Example 1, place the semiconductor device in an etching chamber with a chamber pressure of 30 mTorr, introduce oxygen and argon gas with a flow rate of 100 mL / min and a flow rate of 100 mL / min; generate oxygen and argon plasma by glow discharge, and perform reactive ion etching on the residual polymer at the aperture without affecting the aperture structure, with a radio frequency power of 15 W and a reactive ion etching time of 5 s to remove part of the residual polymer at the aperture and enlarge the aperture.

[0093] Comparative Example 1

[0094] A TEM sample and its preparation method are different from Example 1 only in that the residual polymer at the aperture is not subjected to reactive ion etching, i.e. step (1) is not performed. The other materials, process parameters and steps are the same as those in Example 1.

[0095] The obtained TEM samples were tested using transmission electron microscopy, and the test results are as follows: Figure 4 As shown, if atomic layer deposition is performed directly without reactive ion etching of the residual polymer at the aperture, the precursor material for atomic layer deposition cannot enter the pore structure but accumulates on the surface. The pore structure is not clear under TEM observation, and the observation effect is poor.

[0096] The applicant declares that the detailed process flow of this invention is illustrated by the above embodiments, but this invention is not limited to the above detailed process flow, that is, it does not mean that this invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A method of preparing a TEM sample, characterized by, The preparation method includes the following steps: (1) A semiconductor device having a hole structure is provided; the hole structure is formed by etching the semiconductor device with plasma of fluorocarbon gas; residual polymer formed during the etching process is deposited at the opening of the hole on the surface of the semiconductor device; Without affecting the pore structure, the residual polymer at the pore opening is removed by reactive ion etching using plasma of oxygen and carrier gas, thereby enlarging the pore opening. (2) Mark the target region containing the hole structure on the semiconductor device; (3) Apply a protective colloid to the surface of the target area to form a protective layer; (4) The target region is separated from the body of the semiconductor device using a first focused ion beam to obtain a first sample; (5) The first sample is thinned using a second focused ion beam to obtain the TEM sample.

2. The preparation method according to claim 1, characterized in that, The diameter of the pore structure is 10-70 nm, and the depth is 50-3000 nm.

3. The preparation method according to claim 1, characterized in that, The fluorocarbon gas includes any one or a combination of at least two of CHF3, CH2F2, CH3F, or CF4.

4. The preparation method according to claim 1, characterized in that, The carrier gas includes any one or a combination of at least two of helium, nitrogen, or argon.

5. The preparation method according to claim 1, characterized in that, The chamber pressure for the reactive ion etching is 5-100 millitor.

6. The preparation method according to claim 1, characterized in that, The radio frequency power of the reactive ion etching is 10-50W.

7. The preparation method according to claim 1, characterized in that, In the reactive ion etching, the flow rates of oxygen and carrier gas are each 10-100 mL / min independently.

8. The preparation method according to claim 7, characterized in that, The flow rate ratio of oxygen to carrier gas in the reactive ion etching is (1-2):

1.

9. The preparation method according to claim 1, characterized in that, The reactive ion etching time is 5-60 s.

10. The preparation method according to claim 1, characterized in that, The gas generated during the reactive ion etching process is discharged through a gas extraction system.

11. The preparation method according to claim 1, characterized in that, The marking process includes an atomic layer deposition step on the pore walls of the pore structure.

12. The preparation method according to claim 11, characterized in that, The thickness of the thin film formed by atomic layer deposition is 1-10 nm.

13. The preparation method according to claim 11, characterized in that, The precursor materials for the atomic layer deposition include tetra(dimethylamino)hafnium and / or trimethylaluminum.

14. The preparation method according to claim 1, characterized in that, The protective colloid includes epoxy resin adhesive.

15. The preparation method according to claim 1, characterized in that, The thickness of the protective layer is 20-300 nm.

16. The preparation method according to claim 1, characterized in that, The coating process also includes a heat treatment step.

17. The preparation method according to claim 16, characterized in that, The heat treatment temperature is 50-100℃.

18. The preparation method according to claim 16, characterized in that, The heat treatment time is 10-30 minutes.

19. The preparation method according to claim 1, characterized in that, The current of the first focused ion beam is 90-9900 pA and the voltage is 8-30 kV.

20. The preparation method according to claim 1, characterized in that, The first sample has a length of 2-10 μm, a width of 3-5 μm, and a thickness of 1-2 μm.

21. The preparation method according to claim 1, characterized in that, The second focused ion beam has a beam current of 41-260 pA and a voltage of 2-30 kV.

22. The preparation method according to claim 1, characterized in that, The thinning process is carried out until the thickness of the sample is 10-80 nm.

23. The preparation method according to claim 1, characterized in that, The preparation method specifically includes the following steps: (1) A semiconductor device containing a hole structure is provided; the hole structure is formed by etching the semiconductor device with plasma of fluorocarbon gas; residual polymer formed during the etching process is deposited at the opening of the hole on the surface of the semiconductor device; the diameter of the hole structure is 10-70 nm and the depth is 50-3000 nm. Without affecting the hole structure, the residual polymer at the hole opening is subjected to reactive ion etching using plasma of oxygen and carrier gas to remove part of the residual polymer at the hole opening, thereby enlarging the hole opening. The gas generated during the reactive ion etching process is discharged through a vacuum system. The chamber pressure for the reactive ion etching is 5-100 mTorr, the radio frequency power is 10-50 W, and the flow rates of oxygen and carrier gas are each 10-100 mL / min; the flow rate ratio of oxygen to carrier gas is (1-2):1; and the time for the reactive ion etching is 5-60 s. (2) After performing atomic layer deposition on the pore walls of the pore structure to form a thin film with a thickness of 1-10 nm, the target area containing the pore structure is marked on the semiconductor device; (3) Apply the protective colloid to the surface of the target area, and then heat treat it at 50-100℃ for 10-30 min to form a protective layer with a thickness of 20-300nm; (4) The target region is separated from the body of the semiconductor device using a first focused ion beam with a beam current of 90-9900pA and a voltage of 8-30kV to obtain a first sample. The first sample has a length of 2-10μm, a width of 3-5μm, and a thickness of 1-2μm. (5) The first sample is thinned to a thickness of 10-80 nm using a second focused ion beam with a beam current of 41-260 pA and a voltage of 2-30 kV to obtain the TEM sample.

24. A TEM sample, characterized in that, The TEM sample was prepared using the preparation method described in any one of claims 1-23.

25. A method for measuring the dimensions of a hole structure in a semiconductor device, characterized in that, The measurement method includes: The TEM sample as described in claim 24 was observed and the dimensions of the pore structure in the semiconductor device were measured.

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