CN112557430A - Sample characterization method - Google Patents

Sample characterization method Download PDF

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CN112557430A
CN112557430A CN202011312307.7A CN202011312307A CN112557430A CN 112557430 A CN112557430 A CN 112557430A CN 202011312307 A CN202011312307 A CN 202011312307A CN 112557430 A CN112557430 A CN 112557430A
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energy loss
target layer
interval
target
transmission electron
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CN112557430B (en
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刘军
魏强民
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Yangtze Memory Technologies Co Ltd
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Yangtze Memory Technologies Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
    • G01N23/223—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
    • G01N23/20091—Measuring the energy-dispersion spectrum [EDS] of diffracted radiation

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Abstract

The embodiment of the application provides a sample characterization method, which is applied to a transmission electron microscope and comprises the following steps: obtaining a sample to be characterized, wherein the sample to be characterized comprises a target layer and at least one non-target layer; determining a first energy loss interval according to a first electron energy loss spectrum of the target layer and a second electron energy loss spectrum of the non-target layer; selecting an energy loss value in the first energy loss interval as a target working parameter of the transmission electron microscope; under the energy filtering mode of the transmission electron microscope and the target working parameters, electron beams generated by the transmission electron microscope are projected to the surfaces of a target layer and each non-target layer to obtain a characterization image of a sample to be characterized; and determining the characteristic parameters of the target layer according to the characteristic images, wherein the characteristic parameters comprise the thickness of the target layer and the spatial distribution of the target layer in the sample.

Description

Sample characterization method
Technical Field
The present application relates to the field of material testing, and relates to, but is not limited to, a method of characterizing a sample.
Background
Currently, the characterization of Titanium Nitride (TiN) mainly depends on Transmission Electron Microscope (TEM) and its equipped X-ray Energy Spectrometer (EDS) and Electron Energy Loss Spectrometer (EELS). Among them, a common Transmission Electron microscope (tem) image and a Scanning Transmission Electron Microscope (STEM) image can give information about an interface structure and a morphology, but cannot give information about a composition, and thus, the EDS and the EELS are required to be combined for characterization.
However, in the related art, if there is a material with similar thickness contrast beside the TiN, the boundary of the TiN will be difficult to identify. For example, TiN and aluminum Oxide (Al) in Channel Holes (CH)2O3) Is equivalent to that of (A), and therefore, TiN and Al2O3The boundaries are hard to define strictly. If the TiN is occluded by other diffraction-contrast or heavier materials (e.g., tungsten), the boundaries of the TiN in the TEM or STEM images will become very blurred. Further, although the general distribution of TiN can be determined through the composition information measured by EDS and EELS, the EDS and EELS both have the problem of complicated operation and result analysis, and the EDS is limited by fluorescence, the EELS is limited by collection efficiency (large pixel point), and both cannot well represent the thickness of TiN.
Disclosure of Invention
In view of the above, the embodiments of the present application provide a method for characterizing a sample.
The technical scheme of the application is realized as follows:
the embodiment of the application provides a sample characterization method, which is applied to a transmission electron microscope and comprises the following steps:
obtaining a sample to be characterized, wherein the sample to be characterized comprises a target layer and at least one non-target layer, and the target layer and the non-target layer are made of different materials;
determining a first energy loss interval according to the first electron energy loss spectrum of the target layer and the second electron energy loss spectrum of the non-target layer, wherein each semaphore of the first electron energy loss spectrum in the first energy loss interval is larger than each corresponding second semaphore of the second electron energy loss spectrum in the first energy loss interval;
selecting an energy loss value in the first energy loss interval as a target working parameter of the transmission electron microscope;
projecting an electron beam generated by the transmission electron microscope to the surfaces of the target layer and each of the non-target layers in an energy filtering mode of the transmission electron microscope and the target operating parameters to obtain a characterization image of the sample;
and determining the characterization parameters of the target layer according to the characterization image, wherein the characterization parameters comprise the thickness of the target layer and the spatial distribution of the target layer in the sample to be characterized.
In some embodiments, prior to determining the first energy loss interval, the method further comprises:
acquiring a first electron energy loss spectrum of the target layer and a second electron energy loss spectrum of the non-target layer;
correspondingly, the determining a first energy loss interval according to the first electron energy loss spectrum of the target layer and the second electron energy loss spectrum of the non-target layer includes:
under each energy loss value, acquiring a first semaphore in the first electron energy loss spectrum and a second semaphore in the second electron energy loss spectrum;
comparing the first semaphore with the second semaphore, and determining an energy loss interval in which the first semaphore is larger than the second semaphore as a first energy loss interval.
In some embodiments, the selecting the energy loss value in the first energy loss interval as the target operating parameter of the transmission electron microscope includes:
determining a difference between the first semaphore and each of the second semaphores at each energy loss value in the first energy loss interval;
determining, at each energy loss value, a ratio between the difference and the second semaphore as a semaphore ratio between the target layer and the non-target layer at the corresponding energy loss value;
in the first energy loss interval, determining continuous subintervals with the signal quantity ratios larger than a signal quantity threshold as second energy loss intervals;
and selecting the energy loss value in the second energy loss interval as a target working parameter of the transmission electron microscope.
In some embodiments, the selecting the energy loss value in the second energy loss interval as the target operating parameter of the transmission electron microscope includes:
and selecting any one energy loss value or any section of energy loss value interval in the second energy loss interval as the target working parameter.
In some embodiments, the target layer comprises titanium nitride and the non-target layer comprises tungsten and/or high K dielectric, the target layer and the non-target layer being in contact with each other.
In some embodiments, the first energy loss interval comprises 40eV to 70 eV.
In some embodiments, the second energy loss interval comprises 45eV to 55 eV.
In some embodiments, the selecting the energy loss value in the first energy loss interval as the target operating parameter of the transmission electron microscope includes:
and selecting an energy loss interval with an interval width of 10eV in the first energy loss interval as a selection interval of the target working parameter.
In some embodiments, the sample to be characterized comprises: a trench hole of a three-dimensional memory;
the target layer comprises titanium nitride formed on the side wall of the channel hole, the non-target layer comprises high-K medium and/or tungsten, and the non-target layer is stacked on one side, facing to or departing from the channel hole, of the target layer.
In some embodiments, the characterization image comprises an energy-filtered, transmission electron image;
in the energy-filtered, transmitted-electron image, the first contrast of the target layer is greater than the second contrast of each of the non-target layers.
The embodiment of the application provides a sample characterization method, a first energy loss interval is determined according to a first electron energy loss spectrum of a target layer and a second electron energy loss spectrum of a non-target layer in a sample to be characterized, an energy loss value in the first energy loss interval is selected and used as a target working parameter of a transmission electron microscope, a characterization image of the sample to be characterized is obtained under an energy filtering mode and the target working parameter of the transmission electron microscope, and the characterization parameter of the target layer is determined through the characterization image.
Drawings
In the drawings, which are not necessarily drawn to scale, like reference numerals may describe similar components in different views. Like reference numerals having different letter suffixes may represent different examples of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed herein.
FIG. 1A is a transmission electron micrograph of a trench hole in a related art;
FIG. 1B is a diagram showing an energy spectrum of a channel hole in the related art;
FIG. 2 is a schematic flow chart of an alternative implementation of a sample characterization method provided in an embodiment of the present application;
FIG. 3 is a schematic flow chart of an alternative implementation of a sample characterization method provided in the embodiments of the present application;
FIG. 4 is a schematic flow chart of an alternative implementation of a sample characterization method provided in the embodiments of the present application;
FIG. 5A is a schematic flow chart illustrating an implementation of a sample characterization method provided in an embodiment of the present application;
FIG. 5B is a graph of electron energy loss spectra for various materials provided in accordance with an embodiment of the present application;
FIG. 5C is a graph of semaphore ratio distribution for TiN and HK at different values of energy loss, as provided by an embodiment of the present application;
FIG. 5D is a bright field image of a transmission electron microscope of a trench hole in the related art;
fig. 5E is an energy filtered transmission electron image of a channel hole provided by an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, specific technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings in the embodiments of the present application. The following examples are intended to illustrate the present application but are not intended to limit the scope of the present application.
In the following description, suffixes such as "module" or "unit" used to denote elements are used only for facilitating the explanation of the present application, and have no specific meaning in themselves. Thus, "module" or "unit" may be used mixedly.
In large scale integrated circuits, titanium nitride is widely used as a Glue layer (Glue layer) of tungsten (W). The composition and morphology of TiN has a significant effect on the W particle size (Grain size) and the filling. Especially in the three-dimensional flash memory array area, how to clearly characterize the composition and spatial distribution of TiN is crucial.
In the related art, the distribution of titanium nitride is characterized by a transmission electron microscope and an X-ray energy spectrometer and an electron energy loss spectrometer equipped with the same, wherein common TEM and STEM images can give information on the interface structure and morphology, and EDS and EELS can give information on the composition distribution.
However, in the related art, if there is a material with similar thickness contrast beside the TiN, the boundary of the TiN will be difficult to identify. Such as TiN in Channel Holes (CH) and high dielectric materials (Al)2O3) Due to TiN and Al in CH2O3Is equivalent to that of (A), and therefore, TiN and Al2O3The boundaries of (a) are difficult to define strictly. The boundaries of TiN in TEM or STEM images become very blurred if shielded by other diffraction-contrast strong or heavier materials (e.g., tungsten). FIG. 1A is a transmission electron micrograph of a trench hole in the related art, and it can be seen thatTitanium nitride 101 and Al2O3The boundary of 102 is very fuzzy and indistinguishable.
Further, although the composition information can be obtained by EDS and EELS, the general distribution of TiN is clarified. As shown in fig. 1B, which is an energy spectrum of a channel hole in the related art, wherein the thickness of a channel hole sample is about 15nm, a portion 103 of a graph shows the distribution of Ti element (i.e., TiN), a portion 104 of a graph shows the distribution of W element (i.e., tungsten wire), and a portion c of a graph shows the energy spectrum of the entire channel hole, and the general distribution of TiN can be seen in the combination of a graph, B graph and c graph. However, both EDS and EELS have significant shortcomings in characterizing TiN distribution and monitoring TiN thickness. For example, EDS and EELS both suffer from the problem of complex operation and analysis of results (analysis of a single picture takes about half an hour); and EDS is limited by fluorescence (TiN is usually photographed to be thick), EELS is limited by collection efficiency (pixel point is large), and the EDS cannot well represent the thickness of TiN.
Based on the above problems in the related art, the embodiments of the present application provide a sample characterization method, so that the sample has an image contrast that is easier to identify, and the spatial distribution of the sample does not need to be determined by EDS and EELS, thereby greatly simplifying the characterization process.
Example one
Fig. 2 is a schematic flow chart of an alternative implementation of a sample characterization method provided in an embodiment of the present application, where the sample characterization method is applied to a transmission electron microscope, and as shown in fig. 2, the method includes the following steps:
step S201, obtaining a sample to be characterized, wherein the sample to be characterized comprises a target layer and at least one non-target layer, and the target layer and the non-target layer are made of different materials.
The sample to be characterized may be a three-dimensional bulk material comprising a plurality of layers or materials. In an embodiment of the present application, the sample to be characterized includes a target layer and at least one non-target layer. The target layer is a substance which needs to be characterized finally, the at least one non-target layer is adjacent to the target layer respectively, and the target layer and the non-target layer are different in material.
Step S202, determining a first energy loss interval according to the first electron energy loss spectrum of the target layer and the second electron energy loss spectrum of the non-target layer.
In the embodiment of the application, an energy loss signal after interaction of incident electrons and a target layer is detected through an electron energy loss spectrometer so as to obtain a first electron energy loss spectrum; and detecting an energy loss signal after the interaction of the incident electrons and the non-target layer through an energy loss spectrometer to obtain a second electron energy loss spectrum. Here, each signal quantity of the first electron energy loss spectrum in the first energy loss interval is larger than each corresponding second signal quantity of the second electron energy loss spectrum in the first energy loss interval.
And S203, selecting the energy loss value in the first energy loss interval as a target working parameter of the transmission electron microscope.
The target working parameters are the working parameters of the transmission electron microscope when the sample to be characterized is characterized. The sample characterization method provided by the embodiment of the application is applied to a transmission electron microscope, and before the sample to be characterized is characterized, the target working parameters of the transmission electron microscope need to be obtained. Here, an energy loss value is selected from the first energy loss section as a target operating parameter.
Step S204, under the energy filtering mode of the transmission electron microscope and the target working parameters, projecting the electron beams generated by the transmission electron microscope to the surfaces of the target layer and each non-target layer to obtain a characterization image of the sample to be characterized.
In some embodiments, the energy filtering mode of the transmission electron microscope is a transmission electron microscope with energy filtering, the purpose of the energy filtering is to improve the energy resolution, and in the energy filtering mode of the transmission electron microscope, the analysis of the distribution and the like of elements in the micro-area of the sample to be characterized is more accurate.
The target working parameters of the transmission electron microscope are the attribute parameters of each part of the transmission electron microscope when the transmission electron microscope carries out normal representation on a sample to be represented. The characterization image is a transmission electron microscope image of the sample to be characterized, which is obtained in the energy filtering mode of the transmission electron microscope. Here, the first contrast of the target layer in the transmission electron microscope image of the sample to be characterized is greater than the second contrast of each non-target layer.
And S205, determining the characterization parameters of the target layer according to the characterization image.
The characterization parameters are parameters for characterizing the target layer, wherein the target layer characterization parameters include the thickness of the target layer and the spatial distribution of the target layer in the sample. The characterization image comprises an Energy-Filtered Transmission Electron Microscopy (EFTEM); in the characterization image, a first contrast of the target layer is greater than a second contrast of each of the non-target layers.
In the embodiment of the application, because the first contrast of the target layer is greater than the second contrast of each non-target layer in the characterization image, the spatial distribution of the target layer can be clearly seen from the characterization image, and the thickness of the target layer can be automatically measured and obtained by adopting software such as Digital Micrograph and the like.
According to the sample characterization method, the first energy loss interval is determined according to the first electron energy loss spectrum of the target layer and the second electron energy loss spectrum of the non-target layer in the sample to be characterized, the energy loss value in the first energy loss interval is selected and used as the target working parameter of the transmission electron microscope, the characterization image of the sample to be characterized is obtained under the energy filtering mode and the target working parameter of the transmission electron microscope, and the characterization parameter of the target layer is determined through the characterization image.
Example two
Fig. 3 is a schematic flow chart of an alternative implementation of a sample characterization method provided in an embodiment of the present application, where the characterization method is applied to a transmission electron microscope, as shown in fig. 3, and the method includes the following steps:
step S301, a sample to be characterized is obtained, wherein the sample to be characterized comprises a target layer and at least one non-target layer, and the target layer and the non-target layer are made of different materials.
The implementation process and implemented functions of step S301 are the same as those of step S201 in the above-described embodiment.
Step S302, a first electron energy loss spectrum of the target layer and a second electron energy loss spectrum of the non-target layer are obtained.
In this embodiment of the application, when the first electron energy loss spectrum is obtained, a difference between the thickness of the target layer and the thickness of the non-target layer when the second electron energy loss spectrum is obtained is smaller than a thickness threshold, and when the thickness threshold is 0, the contrast between the first electron energy loss spectrum and the second electron energy loss spectrum is strongest.
Step S303, acquiring a first semaphore in the first electron energy loss spectrum and a second semaphore in the second electron energy loss spectrum at each energy loss value.
In some embodiments, the first semaphore is an energy loss condition of the target layer at each energy loss value, and the first semaphore of the target layer at each energy loss value can be acquired through the first electron energy loss spectrum. The second semaphore is the energy loss condition of the non-target layer under different energy loss values, and the second semaphore of the non-target layer under different energy loss values can be obtained through the second electron energy loss spectrum.
Step S304, comparing the first semaphore and the second semaphore, and determining an energy loss interval in which the first semaphore is greater than the second semaphore as a first energy loss interval.
Step S305, selecting the energy loss value in the first energy loss interval as a target working parameter of the transmission electron microscope.
In this embodiment of the present application, any energy loss value in the first energy loss interval may be selected as the target operating parameter of the transmission electron microscope, or an energy loss subinterval having a preset characteristic may be determined in the first energy loss interval, and any energy loss value in the energy loss subinterval is used as the target operating parameter, where the preset characteristic includes: the magnitude of a ratio between a difference value of the first semaphore and the corresponding second semaphore and the second semaphore, wherein in the energy loss subinterval, the ratio is larger than a preset ratio.
Step S306, under the energy filtering mode of the transmission electron microscope and the target working parameters, projecting the electron beams generated by the transmission electron microscope to the surfaces of the target layer and each non-target layer to obtain the characterization image of the sample to be characterized.
Here, by obtaining the target operating parameter of the transmission electron microscope and setting the operating parameter of the transmission electron microscope as the target operating parameter, the characterization image of the sample to be characterized can be obtained in the energy filtering mode of the transmission electron microscope.
In this embodiment of the present application, the target operating parameter is determined by comparing a first electron energy loss spectrum of the target substance with a second electron energy loss spectrum of the non-target substance, and selecting an energy loss interval in which each first signal quantity in the first electron energy loss spectrum is greater than a corresponding second signal quantity in the second electron energy loss spectrum, so that in the characterization map, the first contrast of the target layer is greater than the second contrast of the non-target layer.
And S307, determining the characterization parameters of the target layer according to the characterization image.
The implementation process and implemented functions of step S307 are the same as those of step S205 in the above-described embodiment.
According to the sample characterization method provided by the embodiment of the application, the first electron energy loss spectrum of the target layer and the second electron energy loss spectrum of the non-target layer in the sample to be characterized are compared, the energy loss interval in which the first semaphore in the first electron energy loss spectrum is larger than the second semaphore in the second electron energy loss spectrum is determined as the first energy loss interval, the energy loss value of the first energy loss interval is selected as the target working parameter of the transmission electron microscope, the characterization image of the sample to be characterized is obtained under the energy filtering mode and the target working parameter of the transmission electron microscope, and the characterization parameter of the target layer is determined through the characterization image.
EXAMPLE III
Fig. 4 is a schematic flow chart of an alternative implementation of a sample characterization method provided in an embodiment of the present application, which is applied to a transmission electron microscope, as shown in fig. 4, and includes the following steps:
step S401, a sample to be represented is obtained, wherein the sample to be represented comprises a target layer and at least one non-target layer, and the target layer and the non-target layer are different in material.
In some embodiments, the sample to be characterized may include: channel Holes (CH) of the three-dimensional memory; the target layer comprises titanium nitride formed on the sidewall of the channel hole CH, and the non-target layer comprises high-K dielectric (e.g., Al)2O3) And/or tungsten (W), the non-target layer is laminated on one side of the target layer facing to or departing from the channel hole CH, and the target layer and the non-target layer are in contact with each other.
Step S402, determining a first energy loss interval according to the first electron energy loss spectrum of the target layer and the second electron energy loss spectrum of the non-target layer.
Here, each signal quantity of the first electron energy loss spectrum in the first energy loss interval is larger than each corresponding second signal quantity of the second electron energy loss spectrum in the first energy loss interval. In an embodiment of the present application, the first energy loss interval includes 40eV to 70 eV.
And S403, selecting the energy loss value in the first energy loss interval as a target working parameter of the transmission electron microscope.
In some embodiments, the selecting the energy loss value in the first energy loss interval as the target operating parameter of the transmission electron microscope includes the following steps:
step S4031, in the first energy loss interval, a difference between the first semaphore and each of the second semaphores at each energy loss value is determined.
Step S4032, at each energy loss value, determine a ratio between the difference and the second signal amount as a signal amount ratio between the target layer and the non-target layer at the corresponding energy loss value.
Step S4033, in the first energy loss interval, determine sub-intervals in which the signal-quantity ratios are all greater than a signal-quantity threshold and are continuous, as a second energy loss interval.
And step S4034, selecting the energy loss value in the second energy loss interval as a target working parameter of the transmission electron microscope.
Here, the second energy loss section is located in the first energy loss section, and a width of the second energy loss section is greater than a preset width, which may be 8eV or 10eV, including 45eV to 55 eV.
In the embodiment of the application, firstly, in a first energy loss interval, a difference value between a first semaphore of a target layer and a second semaphore of each non-target layer at each energy loss value is determined; secondly, determining the ratio of the difference value to the second semaphore under each energy loss value as the semaphore ratio between a target layer and a non-target layer under the corresponding energy loss value, and determining continuous subintervals with the semaphore ratios larger than the semaphore threshold value in the first energy loss interval as the second energy loss interval; finally, a target energy loss value of the transmission electron microscope is determined in the second energy loss interval. Here, the semaphore threshold may be 55% or 65%.
In some embodiments, the selecting the energy loss value in the second energy loss interval as the target operating parameter of the transmission electron microscope includes: and selecting any one energy loss value or any section of energy loss value interval in the second energy loss interval as the target working parameter.
For example, the second energy loss interval includes: 45eV to 50eV, the target operating parameter may be any one of 45eV, 47eV, 49eV or 50eV, or the target operating parameter may be an energy loss interval of 46-48 eV.
In some embodiments, the selecting the energy loss value in the first energy loss interval as the target operating parameter of the transmission electron microscope includes: and selecting an energy loss interval with an interval width of 10eV in the first energy loss interval as a selection interval of the target working parameter.
Step S404, under the energy filtering mode of the transmission electron microscope and the target working parameters, projecting the electron beams generated by the transmission electron microscope to the surfaces of the target layer and each non-target layer to obtain an energy filtering transmission electron image of the sample to be characterized.
Here, the energy-filtered transmission electron image is an image of a specimen to be characterized acquired in an energy-filtering mode of the transmission electron microscope. When the sample to be characterized is a channel hole, the target layer is titanium nitride, and the non-target layer is aluminum oxide or tungsten, in the energy-filtering transmission electron image, the first contrast of the titanium nitride is greater than the second contrast of the aluminum oxide, or the first contrast of the titanium nitride is greater than the second contrast of the tungsten.
And S405, determining the characterization parameters of the target layer according to the characterization image.
The implementation process and implemented functions of step S405 are the same as those of step S205 in the above-described embodiment.
In the embodiment of the application, because the first contrast of the titanium nitride in the energy filtering transmission electron image of the channel hole is greater than the second contrast of the aluminum oxide or the tungsten, the thickness and the spatial distribution of the titanium nitride can be accurately and quickly obtained by filtering the transmission electron image through the energy of the channel hole, and thus, the characterization process is greatly simplified.
Example four
Fig. 5A is a schematic flow chart of an implementation of a sample characterization method applied to a transmission electron microscope, where the sample to be characterized is a channel hole, and the target layer is titanium nitride. Here, the channel hole further includes therein: High-K (HK) filled in the channel hole, and tungsten and silicon dioxide (SiO) around the channel hole2) And single crystal silicon (Poly). As shown in fig. 5A, the method includes the steps of:
step S501, analyzing electron energy loss peaks of all substances in the channel holes.
In the electron energy loss spectrum, the intensity of the low-loss region energy loss signal is different according to the element type and the chemical environment, and first, the low loss peak (low loss) of each substance in the channel hole under the similar thickness is compared, as shown in fig. 5B, the electron energy loss spectrum pattern diagram of different materials provided by the embodiment of the present application can find that the peak position and the shape of each material are greatly different. By comparative analysis of the low loss peaks of TiN and other substances in the channel hole, it was found that the Plasmon loss peak (Plasmon) of TiN and SiO2、HK(Al2O3) Particularly, the electron energy loss spectrum of TiN is higher than that of SiO in the channel hole in the range of 40eV to 70eV2And Poly electron energy loss spectra.
Step S502, an energy slit section of the transmission electron microscope (corresponding to the second energy loss section in the above-described embodiment) is determined.
Because both sides of TiN are HK (Al) respectively2O3) And W, the energy loss spectrum peak of TiN is higher than that of other substances in the channel hole, the TiN and HK (Al) should be selected2O3) The most significant energy difference from WAnd (4) measuring. In the electron energy loss spectrum, Al is present in the energy band of 40eV to 60eV2O3Is stronger than the W semaphore. So TiN and HK (Al)2O3) The ratio of the signal quantities of (a) is the key to the selection of the energy slot interval.
As shown in FIG. 5C, the distribution of the semaphore ratio of TiN and HK provided for the embodiments of the present application at different energy loss values shows that the TiN semaphores are about 55% higher than HK between 46.5 to 53.2eV (as shown in the interval A in FIG. 5C) by analyzing the energy band of 30eV to 70eV (TiN-HK)/HK, which is the most distinct region. Limited to GIF states, but too small an energy slit interval tends to cause imaging distortion. In addition, the signal-to-Noise Ratio (SNR) is difficult to be ensured even in an excessively small energy slit interval. The energy slit interval is finally determined to be 45eV to 55eV (as in B interval in fig. 5C) by taking contrast, signal-to-noise ratio and other factors into consideration.
And S503, acquiring an energy filtering transmission electron image in the energy filtering mode and the energy slit interval of the transmission electron microscope.
And step S504, determining the characterization parameters of the titanium nitride through the energy filtered transmission electron image.
The characterization parameters of the titanium nitride comprise the thickness of the titanium nitride and the spatial distribution of the titanium nitride in the channel hole. Fig. 5D is a bright field image of a transmission electron microscope of a channel hole in the related art, and fig. 5E is an energy-filtered transmission electron image of a channel hole provided in an embodiment of the present application, where diagrams a, b, and c in fig. 5D and 5E are channel holes in memories of different models, respectively. Comparing fig. 5D and 5E, it can be seen that after the imaging conditions are optimized, the TiN 501 is obviously highlighted (Highlight). Therefore, the thickness of TiN can be automatically measured based on the energy-filtered transmission electron image obtained by the sample characterization method provided by the embodiment of the application. As can be seen from the energy filtered transmission electron image in fig. 5E, the TiN in the b plot is significantly coarser than the TiN in the a plot. And the characterization method of the sample provided in the example of the present application also confirmed that TiN is in an island-like form (as shown in c in fig. 5E).
In the embodiment of the application, in an energy filtering mode of a transmission electron microscope, the position of an energy slit (corresponding to target working parameters in the embodiment) is 50eV, the width of the energy slit is 10eV, the image contrast of TiN in an obtained EFTEM image is strongest, and the image contrast of other materials such as metal, silicon nitride, monocrystalline silicon, silicon oxide and the like is weak, so that the information such as the thickness, the spatial distribution and the like of TiN can be directly obtained according to the EFTEM image.
Compared with a common TEM image, the energy-filtered transmission electron image obtained by the sample characterization method provided by the embodiment of the application has the advantage of easy-to-identify TiN image contrast, and TiN distribution does not need to be judged by means of EDS and EELS, so that the characterization process is greatly simplified.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in a non-target manner. The above-described device embodiments are merely illustrative, for example, the division of the unit is only a logical functional division, and there may be other division ways in actual implementation, such as: multiple units or components may be combined, or may be integrated into another system, or some features may be omitted, or not implemented. In addition, the coupling, direct coupling or communication connection between the components shown or discussed may be through some interfaces, indirect coupling or communication connection between devices or units, and may be electrical, mechanical or non-target.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed on a plurality of network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, all the functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may be separately used as one unit, or two or more units may be integrated into one unit; the integrated unit can be realized in a form of hardware, or in a form of hardware plus a software functional unit. Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: a mobile storage device, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The methods disclosed in the several method embodiments provided in the present application may be combined arbitrarily without conflict to obtain new method embodiments.
The features disclosed in the several method or apparatus embodiments provided in the present application may be combined arbitrarily, without conflict, to arrive at new method embodiments or apparatus embodiments.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims (10)

1. A method of characterizing a sample for use in a transmission electron microscope, the method comprising:
obtaining a sample to be characterized, wherein the sample to be characterized comprises a target layer and at least one non-target layer, and the target layer and the non-target layer are made of different materials;
determining a first energy loss interval according to the first electron energy loss spectrum of the target layer and the second electron energy loss spectrum of the non-target layer, wherein each semaphore of the first electron energy loss spectrum in the first energy loss interval is larger than each corresponding second semaphore of the second electron energy loss spectrum in the first energy loss interval;
selecting an energy loss value in the first energy loss interval as a target working parameter of the transmission electron microscope;
under the energy filtering mode of the transmission electron microscope and the target working parameters, projecting the electron beams generated by the transmission electron microscope to the surfaces of the target layer and each non-target layer to obtain a characterization image of the sample to be characterized;
and determining the characterization parameters of the target layer according to the characterization images, wherein the characterization parameters comprise the thickness of the target layer and the spatial distribution of the target layer in the sample.
2. The method of claim 1, wherein prior to determining the first energy loss interval, the method further comprises:
acquiring a first electron energy loss spectrum of the target layer and a second electron energy loss spectrum of the non-target layer;
correspondingly, the determining a first energy loss interval according to the first electron energy loss spectrum of the target layer and the second electron energy loss spectrum of the non-target layer includes:
under each energy loss value, acquiring a first semaphore in the first electron energy loss spectrum and a second semaphore in the second electron energy loss spectrum;
comparing the first semaphore with the second semaphore, and determining an energy loss interval in which the first semaphore is larger than the second semaphore as a first energy loss interval.
3. The method of claim 1, wherein selecting the energy loss value in the first energy loss interval as the target operating parameter of the transmission electron microscope comprises:
determining a difference between the first semaphore and each of the second semaphores at each energy loss value in the first energy loss interval;
determining, at each energy loss value, a ratio between the difference and the second semaphore as a semaphore ratio between the target layer and the non-target layer at the corresponding energy loss value;
in the first energy loss interval, determining continuous subintervals with the signal quantity ratios larger than a signal quantity threshold as second energy loss intervals;
and selecting the energy loss value in the second energy loss interval as a target working parameter of the transmission electron microscope.
4. The method of claim 2, wherein selecting the energy loss value in the second energy loss interval as the target operating parameter of the transmission electron microscope comprises:
and selecting any one energy loss value or any section of energy loss value interval in the second energy loss interval as the target working parameter.
5. The method of claim 1, wherein the target layer comprises titanium nitride and the non-target layer comprises tungsten and/or high-K dielectric, the target layer and the non-target layer being in contact with each other.
6. The method of claim 5, wherein the first energy loss interval comprises 40eV to 70 eV.
7. The method of claim 6, wherein the second energy loss interval comprises 45eV to 55 eV.
8. The method of claim 1, wherein selecting the energy loss value in the first energy loss interval as the target operating parameter of the transmission electron microscope comprises:
and selecting an energy loss interval with an interval width of 10eV in the first energy loss interval as a selection interval of the target working parameter.
9. The method of claim 1, wherein the sample to be characterized comprises: a trench hole of a three-dimensional memory;
the target layer comprises titanium nitride formed on the side wall of the channel hole, the non-target layer comprises high-K medium and/or tungsten, and the non-target layer is stacked on one side, facing to or departing from the channel hole, of the target layer.
10. The method of claim 1, wherein the characterization image comprises an energy-filtered transmission electron image;
in the energy-filtered, transmitted-electron image, the first contrast of the target layer is greater than the second contrast of each of the non-target layers.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113097089A (en) * 2021-03-30 2021-07-09 长江存储科技有限责任公司 Method and system for determining film continuity
CN113310442A (en) * 2021-04-27 2021-08-27 长江存储科技有限责任公司 Thickness measuring method and device
CN113643996A (en) * 2021-07-30 2021-11-12 长江存储科技有限责任公司 Compactness characterization method
CN114216917A (en) * 2021-11-23 2022-03-22 长江存储科技有限责任公司 Method for characterizing test samples

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009244001A (en) * 2008-03-31 2009-10-22 Hitachi High-Technologies Corp Transmission electron microscope equipped with electron spectrometer
CN102262997A (en) * 2010-05-12 2011-11-30 Fei公司 Simultaneous electron detection
CN105806853A (en) * 2014-12-31 2016-07-27 北京有色金属研究总院 Method for monitoring and analyzing micro area metal elements in material
CN108140525A (en) * 2015-09-29 2018-06-08 株式会社日立高新技术 Have the scanning transmission electron microscope and its observation method of electronic energy loss spectrometer
CN109580688A (en) * 2018-12-20 2019-04-05 北京科技大学 For trace impurity concentration in GaN and the high-precision detecting method of distribution
CN110579494A (en) * 2019-09-19 2019-12-17 长江存储科技有限责任公司 Characterization method of metal silicide
CN110687138A (en) * 2019-09-05 2020-01-14 长江存储科技有限责任公司 Method and device for measuring semiconductor structure and extracting boundary characteristic
CN110808112A (en) * 2018-08-06 2020-02-18 斯格瑞公司 TALBOT-LAU X-ray source and interferometry system
WO2020175554A1 (en) * 2019-02-26 2020-09-03 住友金属鉱山株式会社 Positive electrode active material for lithium ion secondary batteries, method for producing positive electrode active material for lithium ion secondary batteries, and lithium ion secondary battery

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009244001A (en) * 2008-03-31 2009-10-22 Hitachi High-Technologies Corp Transmission electron microscope equipped with electron spectrometer
CN102262997A (en) * 2010-05-12 2011-11-30 Fei公司 Simultaneous electron detection
CN105806853A (en) * 2014-12-31 2016-07-27 北京有色金属研究总院 Method for monitoring and analyzing micro area metal elements in material
CN108140525A (en) * 2015-09-29 2018-06-08 株式会社日立高新技术 Have the scanning transmission electron microscope and its observation method of electronic energy loss spectrometer
CN110808112A (en) * 2018-08-06 2020-02-18 斯格瑞公司 TALBOT-LAU X-ray source and interferometry system
CN109580688A (en) * 2018-12-20 2019-04-05 北京科技大学 For trace impurity concentration in GaN and the high-precision detecting method of distribution
WO2020175554A1 (en) * 2019-02-26 2020-09-03 住友金属鉱山株式会社 Positive electrode active material for lithium ion secondary batteries, method for producing positive electrode active material for lithium ion secondary batteries, and lithium ion secondary battery
CN110687138A (en) * 2019-09-05 2020-01-14 长江存储科技有限责任公司 Method and device for measuring semiconductor structure and extracting boundary characteristic
CN110579494A (en) * 2019-09-19 2019-12-17 长江存储科技有限责任公司 Characterization method of metal silicide

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
肖晓玲等: "电子能量损失谱及其在纳米多层膜研究中的应用", 《真空科学与技术学报》 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113097089A (en) * 2021-03-30 2021-07-09 长江存储科技有限责任公司 Method and system for determining film continuity
CN113097089B (en) * 2021-03-30 2022-01-25 长江存储科技有限责任公司 Method and system for determining film continuity
CN113310442A (en) * 2021-04-27 2021-08-27 长江存储科技有限责任公司 Thickness measuring method and device
CN113643996A (en) * 2021-07-30 2021-11-12 长江存储科技有限责任公司 Compactness characterization method
CN113643996B (en) * 2021-07-30 2023-10-27 长江存储科技有限责任公司 Compactibility characterization method
CN114216917A (en) * 2021-11-23 2022-03-22 长江存储科技有限责任公司 Method for characterizing test samples
CN114216917B (en) * 2021-11-23 2024-04-12 长江存储科技有限责任公司 Characterization method of test sample

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