Etching endpoint detection method and device

Abstract

The present invention provides an etching endpoint detection method and device, the etching endpoint detection method comprising: obtaining an etching endpoint element and an etching intermediate element according to an etching endpoint layer; collecting the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element; obtaining a target element concentration time curve of the etching endpoint element according to the current element concentration time curve of the etching endpoint element and the corresponding historical element concentration time curve; determining the target etching endpoint according to the target element concentration in the target element concentration time curve and the historical etching endpoint. The present invention can meet the high-precision etching endpoint detection of samples with different film layer structures.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuit manufacturing, and in particular to an etching endpoint detection method and device. Background Art

[0002] With the rapid development of integrated circuit technology, the preparation process of dynamic random access memory, magnetic random access memory and other components includes dry etching of samples containing multi-layer and nano-thick films. During the dry etching process, it is necessary to monitor the etching progress in real time to ensure that it stops at the desired film layer, that is, to achieve high-precision endpoint detection, thereby ensuring the final device function.

[0003] Existing dry etching endpoint detection technology based on component analysis is usually based on continuous light emission spectrum acquisition of the gas composition of the vacuum chamber, thereby obtaining information on gas reactants and products in the chamber, and comparing the film structure of the sample to be etched to determine the progress of dry etching to achieve endpoint detection; or using mass spectrometry component analysis technology, continuously acquiring secondary ion components generated during the analytical etching process, and comparing the film structure of the sample to be etched to determine the progress of dry etching to achieve endpoint detection. However, during the etching process, the plasma formed by the reaction gas continuously bombards the surface of the sample to be etched, and the multi-layer and nano-thickness film materials of the sample to be etched will successively react physically or chemically with the reaction gas plasma. On the one hand, gaseous products related to the components of the etched film are continuously generated on the surface of the sample to be etched, and on the other hand, these gaseous reaction gases, products and the film material being etched will also continuously emit atomic spectra on the surface of the sample to be etched; afterwards, due to the concentration gradient and the vacuum pump, these gaseous products will be redistributed in the vacuum chamber. Therefore, by continuously detecting the gas composition in the vacuum chamber, the film material being etched can be determined in principle. In order to ensure the efficiency of the etching process, integrated circuit device manufacturing expects to increase the etching rate, but accordingly, an endpoint detection method based on component analysis is required to reflect the dry etching process in near real time. For thicker film layers (more than 10 nanometers), the corresponding etching time is longer. The accuracy requirement for etching endpoint detection is generally nanometer level, and the existing endpoint detection method for detecting gas components in the vacuum chamber can meet the demand; however, for samples to be etched that include ultra-thin film layers (1 nanometer-2 nanometers or even thinner), on the one hand, the endpoint detection accuracy is required to reach 0.1 nanometer level, and on the other hand, the etching time of the corresponding ultra-thin film layer is short (usually less than 10 seconds), and the gaseous products generated by etching different film layers need time (up to several seconds) to diffuse from the sample surface to the vacuum chamber. Therefore, the existing technology has poor real-time performance in reflecting the actual process of dry etching and cannot meet the endpoint detection requirements of ultra-thin film layers.The dry etching process of integrated circuit device manufacturing technology often involves continuous etching of film layers of different thicknesses and different compositions on the wafer. These film layers have a large thickness span and large composition differences. For example, the corresponding sample film layers of magnetic memory include substrate / Ta (3 nanometers) / CuN (20 nanometers) / Ta (3 nanometers) / CuN (20 nanometers) / Ta (0.7 nanometers) / Pt (1.5 nanometers) / 6x[Co (0.5 nanometers) / Pt (0.35 nanometers)] / Co (0.6 nanometers) / Ru (0.8 nanometers) / Co (0.6 nanometers) / 3x[Pt (0.35 nanometers) / Co (0.5 nanometers) )] / Pt(0.25nm) / Ta(0.2nm) / Co(1.2nm) / W(0.25nm) / CoFeB(0.9nm) / MgO(1.46nm) / CoFeB(1.2nm) / W(0.3nm) / CoFeB(0.5nm) / MgO(1.46nm) / Pt(1.5nm) / Ta(3.0nm) / CuN(5nm) / Ta(3nm) / Ru(5nm). The thickness of different film layers can differ by more than 10 times. It is difficult to achieve accurate and efficient endpoint detection by relying solely on the existing vacuum cavity composition analysis technology. Existing etching technology usually only has the endpoint detection capability of detecting the gas composition in the vacuum cavity. As the thin film composition in the integrated circuit field becomes more and more complex and diversified, the accuracy of dry etching will gradually decrease. Even if there are some theoretical models of state transition on the market to fit the etching endpoint, it is impossible to fundamentally solve the problem of mixing of gaseous substances produced by etching in the vacuum cavity, and it is difficult to meet the etching needs of advanced integrated circuit manufacturing.

[0004] In summary, the current endpoint detection method of dry etching based on component analysis faces the following problems:

[0005] 1. The gaseous products corresponding to different etched film layers are easily mixed in the cavity, causing the gas composition analysis results of the vacuum cavity as a whole to be mixed with information of different film layers, resulting in deviations in the judgment results, especially making it difficult to meet the endpoint detection requirements of ultra-thin film layer dry etching;

[0006] 2. In the integrated circuit process, different film layers of the sample to be etched have different thicknesses. The existing endpoint detection method based on component analysis collects the gas composition information of the vacuum chamber as a whole, which makes it difficult to match different etching rates to achieve efficient endpoint detection. Summary of the invention

[0007] The main purpose of the embodiments of the present invention is to provide an etching endpoint detection method and device to meet the requirements of high-precision etching endpoint detection of samples with different film layer structures.

[0008] In order to achieve the above object, an embodiment of the present invention provides an etching endpoint detection method, comprising:

[0009] Obtaining etching endpoint elements and etching intermediate elements according to the etching endpoint layer;

[0010] Collecting the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element;

[0011] Obtaining a target element concentration time curve of the etching endpoint element according to a current element concentration time curve of the etching endpoint element and a corresponding historical element concentration time curve;

[0012] The target etching endpoint is determined based on the target element concentration in the target element concentration time curve and the historical etching endpoint.

[0013] In one embodiment, it also includes:

[0014] The acquisition position is determined according to the thickness of the etching endpoint layer.

[0015] In one embodiment, obtaining a target element concentration time curve of the etching endpoint element according to a current element concentration time curve of the etching endpoint element and a corresponding historical element concentration time curve includes:

[0016] Determine the conversion factor based on the current element concentration time curve and the corresponding historical element concentration time curve;

[0017] The current element concentration-time curve of the etching endpoint element is processed according to the conversion coefficient to obtain the target element concentration-time curve.

[0018] In one embodiment, determining the target etching endpoint according to the target element concentration in the target element concentration time curve and the historical etching endpoint includes:

[0019] Determine endpoint detection parameters based on the target element concentration in the target element concentration time curve and the historical etching endpoint;

[0020] Determine an endpoint detection threshold interval according to the etching endpoint layer;

[0021] The target etching endpoint is determined based on the comparison result of the endpoint detection parameter and the endpoint detection threshold range.

[0022] The embodiment of the present invention further provides an etching endpoint detection device, comprising:

[0023] An etching element acquisition module is used to acquire etching endpoint elements and etching intermediate elements according to the etching endpoint layer;

[0024] The current element concentration time curve module is used to collect the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element;

[0025] A target element concentration time curve module is used to obtain a target element concentration time curve of the etching endpoint element according to the current element concentration time curve of the etching endpoint element and the corresponding historical element concentration time curve;

[0026] The target etching endpoint module is used to determine the target etching endpoint according to the target element concentration in the target element concentration time curve and the historical etching endpoint.

[0027] In one embodiment, it also includes:

[0028] The acquisition position module is used to determine the acquisition position according to the thickness of the etching endpoint layer.

[0029] In one embodiment, the target element concentration time curve module includes:

[0030] A conversion coefficient unit, used to determine a conversion coefficient based on a current element concentration time curve and a corresponding historical element concentration time curve;

[0031] The target element concentration-time curve unit is used to process the current element concentration-time curve of the etching endpoint element according to the conversion coefficient to obtain the target element concentration-time curve.

[0032] In one embodiment, the target etch endpoint module includes:

[0033] An endpoint detection parameter unit, used to determine endpoint detection parameters according to the target element concentration in the target element concentration time curve and the historical etching endpoint;

[0034] An endpoint detection threshold unit, used to determine an endpoint detection threshold according to the etching endpoint layer;

[0035] The target etching endpoint unit is used to determine the target etching endpoint according to the comparison result of the endpoint detection parameter and the endpoint detection threshold.

[0036] An embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the etching endpoint detection method are implemented.

[0037] An embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the etching endpoint detection method are implemented.

[0038] The etching endpoint detection method and device of the embodiment of the present invention first obtains the etching endpoint element and the etching intermediate element according to the etching endpoint layer, and then collects the current element concentration-time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration-time curve of the etching intermediate element to obtain the target element concentration-time curve of the etching endpoint element with the corresponding historical element concentration-time curve, and finally determines the target etching endpoint according to the target element concentration in the target element concentration-time curve and the historical etching endpoint, which can meet the high-precision etching endpoint detection of samples with different film layer structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 paying creative work.

[0040] Figure 1 is a schematic diagram of a gas composition curve in a vacuum chamber obtained by light emission spectrum detection in an embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of a gas composition curve in a vacuum chamber obtained by mass spectrometry in an embodiment of the present invention;

[0042] Figure 3 is a flow chart of an etching endpoint detection method in an embodiment of the present invention;

[0043] Figure 4 is a flow chart of an etching endpoint detection method in another embodiment of the present invention;

[0044] Figure 5 is a schematic diagram of an endpoint detection experimental system in an embodiment of the present invention;

[0045] Figure 6 is a flow chart of S103 in an embodiment of the present invention;

[0046] Figure 7 is a flow chart of S104 in an embodiment of the present invention;

[0047] Figure 8 is a schematic diagram of the gas composition database in the vacuum chamber obtained through mass spectrometry detection;

[0048] Fig. 9 It is a schematic diagram of the gas composition database near the sample surface obtained by mass spectrometry;

[0049] Fig.10is a schematic diagram of a current element concentration time curve and a corresponding historical element concentration time curve in an embodiment of the present invention;

[0050] Fig.11 is a schematic diagram of a target element concentration time curve and a corresponding historical element concentration time curve in an embodiment of the present invention;

[0051] Fig.12 is a structural block diagram of an etching endpoint detection device in an embodiment of the present invention;

[0052] Fig.13 It is a structural block diagram of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0054] Those skilled in the art will appreciate that the embodiments of the present invention may be implemented as a system, device, apparatus, method or computer program product. Therefore, the present disclosure may be specifically implemented in the following forms, namely: complete hardware, complete software (including firmware, resident software, microcode, etc.), or a combination of hardware and software.

[0055] In view of the fact that it is difficult for the existing technology to match different etching rates to achieve efficient endpoint detection, an embodiment of the present invention provides an etching endpoint detection method and device, which comprehensively uses component analysis technologies such as light emission spectrum or mass spectrometry component analysis during dry etching, and continuously collects gas component information that changes with time at three locations, namely, near the sample surface, vacuum chamber, and tail gas, and compares it with a gas component information database obtained by dry etching samples of the same film structure under the same etching process parameters, so as to accurately judge the etching progress, feedback and adjust the etching parameters, and achieve high-precision dry etching endpoint detection and control. During dry etching, the gas components at different gas component analysis locations have different response speeds to etching and different mixing conditions of gas products corresponding to different film layers that are etched successively. By comprehensively analyzing the gas component analysis results at different locations such as near the sample surface, vacuum chamber, and tail gas, the accuracy and efficiency of dry etching endpoint detection can be improved, which is suitable for different etching process parameters and different film structures.

[0056] The present invention first establishes a gas composition information database of samples with specific film structure under specific etching process parameters. The specific film structure refers to the composition and thickness of different film layers of the sample from the substrate upward. The sample is dry-etched using specific etching process parameters, which include the type and flow rate of reactive gas, chamber pressure, RF power supply power and bias voltage. Figure 1 It is a schematic diagram of a gas composition curve in a vacuum chamber obtained by light emission spectrum detection in an embodiment of the present invention. Figure 2 Schematic diagram of the gas composition curve in the vacuum chamber obtained by mass spectrometry in an embodiment of the present invention. Figure 1-Figure 2 As shown, in this process, the results of the changes of the gas components near the sample surface, the vacuum chamber and the tail gas over time are first collected continuously through optical emission spectrum or mass spectrometry analysis to form a reference database. Afterwards, for samples with the same film layer structure, the same etching process parameters are used for dry etching. In this process, the results of the changes of the gas components near the sample surface, the vacuum chamber and the tail gas over time are continuously collected. By comparing the aforementioned reference database, the information of the film layer currently being etched is determined, and it is determined whether to turn off the RF power supply to end the etching. The present invention is described in detail below in conjunction with the accompanying drawings.

[0057] Figure 3 It is a flow chart of the etching endpoint detection method in an embodiment of the present invention. Figure 4 FIG. 4 is a flow chart of an etching endpoint detection method in another embodiment of the present invention. Figure 3-Figure 4 As shown, the etching endpoint detection method includes:

[0058] S101: Obtaining an etching endpoint element and an etching intermediate element according to an etching endpoint layer.

[0059] The etching intermediate element is an element corresponding to the film layer above the etching endpoint layer, and the etching endpoint layer includes the etching endpoint element.

[0060] S102: collecting the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element.

[0061] Figure 5 Schematic diagram of the endpoint detection experimental system in an embodiment of the present invention. Figure 5 As shown, the endpoint detection experimental system includes a vacuum chamber 310; one end of the first pipe 311, the second pipe 314 and the third pipe 315 are connected to the vacuum chamber 310, and the other ends are connected to the first mass spectrometer 340, the second mass spectrometer 341 and the third mass spectrometer 342 respectively; one end of the fourth pipe 312 is connected to the vacuum chamber 310, and the other end is connected to the vacuum pump ( Figure 5The quartz window 313 is connected to the vacuum chamber body 324 for extracting the tail gas of the vacuum chamber; the quartz window 313 is located on the vacuum chamber body; the sample 320 to be etched includes a first film layer 321, a second film layer 322, a third film layer 323 and a substrate 324. For example, for a magnetic random access memory, the film layer may include a non-magnetic metal layer such as tantalum (Ta), a magnetic layer such as cobalt iron boron (CoFeB) and a non-magnetic insulating layer such as magnesium oxide (MgO), and the thickness of the corresponding film layer may be 0.1 nanometers to 1000 nanometers; the substrate may be a silicon wafer, aluminum oxide (Al2O3) and a quartz wafer (SiO2), etc.; the plasma 330 generated during the dry etching process is a plasma formed by reaction gases such as argon (Ar), carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), chlorine (Cl2), boron trichloride (BCl3) and oxygen (O2) under a radio frequency electric field.

[0062] The vacuum chamber detection mass spectrometer 340, the sample surface detection mass spectrometer 341 and the tail gas detection mass spectrometer 342 are used to analyze the gas components generated by dry etching; the vacuum chamber optical emission spectrum test system 350, the sample surface optical emission spectrum test system 351 and the tail gas optical emission spectrum test system 352 are used to analyze the atomic spectrum excited by the plasma; the vacuum chamber optical emission spectrum test system 350 includes a host 353 and an optical fiber 354, which are used to collect gaseous reactants and products 362 (such as BCl3 + , Cl + , Ar and Al) and the atomic spectrum 372 emitted by the film being etched, the wavelength range is generally 200 nanometers to 800 nanometers; the light emission spectrum test system 351 on the sample surface is used to collect gaseous reactants and products 361 (such as BCl3 + , Cl + , Ar and Al) and the atomic spectrum 371 emitted by the film being etched, the wavelength range is generally 200 nanometers to 800 nanometers; the exhaust light emission spectrum test system 352 is used to collect gaseous reactants and products 363 (such as BCl3 + , Cl + , Ar and Al) and the atomic spectrum 373 emitted by the film layer being etched, the wavelength range is generally 200 nanometers to 800 nanometers.

[0063] The present invention uses an endpoint detection experimental system to simultaneously collect real-time gas composition information at three locations: near the sample surface (1 nanometer to 1 meter away from the sample surface), in the vacuum chamber, and in the exhaust gas. By monitoring the etching time and etching rate of different film materials, the etching progress is accurately judged, and then the etching parameters are adjusted by feedback. The flow rate and power of the etching gas are adjusted by the etching rate, ultimately achieving high-precision dry etching endpoint detection and control.

[0064] Figure 8 This is a schematic diagram of the gas composition database in the vacuum chamber obtained through mass spectrometry. Figure 8 As shown in the figure, compared with the actual film structure of the etched sample, it can be seen that when the dry etching method is used to etch the Pt (thickness 1.5 nanometers) / MgO (thickness 1.46 nanometers) / CoFeB (thickness 0.5 nanometers) / W (0.3nm) film layer, due to the thin film layer, on the one hand, the signal-to-noise ratio of the gas concentration curve obtained by component detection is low; on the other hand, the gaseous products corresponding to different etched film layers such as MgO (thickness 1.46 nanometers) / CoFeB (thickness 0.5 nanometers) are easily mixed in the vacuum chamber, causing the component analysis results to mix the information of different film layers, making it difficult to accurately judge the film material currently being etched from the results of the gas composition analysis in the vacuum chamber, and unable to achieve accurate endpoint detection.

[0065] Fig. 9 This is a schematic diagram of the gas composition database near the sample surface obtained through mass spectrometry detection. Fig. 9 As shown in the figure, for the same etched film layer, the gas composition analysis is performed near the sample surface to avoid the mixing of gaseous products corresponding to different etched film layers. On the one hand, the signal has a better signal-to-noise ratio, and on the other hand, the component analysis curve can better distinguish the boundaries of different film layer etching, which is convenient for accurately judging the film material currently being etched and realizing accurate endpoint detection. However, the method of detecting gas composition near the sample surface may fail to detect some elements due to the short duration of signal appearance.

[0066] Depend on Figure 8-Figure 9 It can be seen that the detection of gas near the sample surface by mass spectrometry has better discrimination and recognition than the detection of vacuum chamber gas. This is because after the target material is bombarded by the etching gas, most of the etching elements will stay near the sample, and then diffuse into the vacuum chamber with the etching gas, and then be discharged through the exhaust port. Since there is a time lag for the gas to reach the vicinity of the vacuum chamber detector, the discrimination and recognition of vacuum chamber gas monitoring are relatively weak. However, due to the close proximity to the sample surface, the sample surface detector sometimes has the problem of not being able to detect the target elements.

[0067] Therefore, in order to solve the above problems, the present invention can determine the collection position of the current element concentration time curve of the element corresponding to each etching layer according to the thickness of each etching layer; when the etching layer is the etching end point layer, the collection position is determined according to the thickness of the etching end point layer.

[0068] In specific implementation, when there are multiple layers of continuous ultra-thin films (thickness less than 1 nanometer) in the etched sample or when etching needs to be terminated at the front and rear interfaces of ultra-thin films (thickness less than 1 nanometer), gas mixing is likely to occur in the vacuum chamber. At this time, it is also necessary to select a sample surface detector to detect the etching progress. Gas detection at the exhaust is an optional option to assist in monitoring the etching process.

[0069] For example, when the thickness of the etching layer is less than 1 nanometer, the collection position is the sample surface. When the thickness of the etching layer is greater than or equal to 1 nanometer, the collection position is the vacuum cavity. The layer where the etching intermediate element is located is located in the upper layer of the layer where the etching endpoint element is located; when the thickness of the layer where the etching intermediate element is located is greater than or equal to 1 nanometer, and the thickness of the etching endpoint layer (the layer where the etching endpoint element is located) is less than 1 nanometer, the current element concentration time curve of the etching intermediate element is first collected in the vacuum cavity. When an etching peak appears in the current element concentration time curve of the etching intermediate element, the current element concentration time curve of the etching endpoint element is collected on the sample surface, and compared with the historical element concentration time curve of the etching endpoint element collected on the sample surface. The exhaust component detection is turned on throughout the process and used as a data reference for other sample surfaces and vacuum cavities. When the detection time of a certain film layer exceeds 10% of the etching peak time of the historical element concentration time curve, and the etching peak has not been detected, the exhaust component detection comparison is enabled to ensure the existence of the etching peak and the smooth progress of etching.

[0070] S103: Obtaining a target element concentration-time curve of the etching endpoint element according to the current element concentration-time curve of the etching endpoint element and the corresponding historical element concentration-time curve.

[0071] Figure 6 is a flow chart of S103 in an embodiment of the present invention. Figure 6 As shown, S103 includes:

[0072] S201: Determine a conversion coefficient according to a current element concentration time curve and a corresponding historical element concentration time curve.

[0073] The conversion coefficient includes slope and offset.

[0074] Fig.10 It is a schematic diagram of the current element concentration time curve and the corresponding historical element concentration time curve in an embodiment of the present invention. Fig.11 Schematic diagram of the target element concentration time curve and the corresponding historical element concentration time curve in the embodiment of the present invention. Figure 10-11As shown, taking copper as an example, the historical element concentration time curve (historical etching curve) is set to X(t), the current element concentration time curve (current etching curve) is set to Y(t), and the target element concentration time curve (target etching curve) is set to Y'(t). First, find the background signal and peak value of the etched element in the two curves. The element concentration (etching signal) corresponding to the etching valley in the historical element concentration time curve is X min , the element concentration (etching signal) corresponding to the etching peak is X max ; The element concentration (etching signal) corresponding to the etching valley in the current element concentration time curve is Y min , the element concentration (etching signal) corresponding to the etching peak is Y max The coordinates of the etching end point in the historical element concentration time curve are (X end ,t end ), different etching stop times t can be adjusted by using multiple reference samples end , combined with X-ray fluorescence analysis and X-ray diffraction and other thin film characterization methods to determine the composition of the corresponding sample surface film material, so as to screen out the optimal endpoint value (X end ,t end ).

[0075] After that, the current element concentration time curve is normalized compared with the historical element concentration time curve, which can be calculated according to equation X min = k × Y min +b and X max = k × Y max +b determines the slope k and the bias b.

[0076] S202: Processing the current element concentration-time curve of the etching endpoint element according to the conversion coefficient to obtain a target element concentration-time curve.

[0077] In specific implementation, the Y(t) curve may be normalized to Y'(t), that is, Y'(t)=k×Y(t)+b.

[0078] S104: Determine a target etching endpoint according to the target element concentration in the target element concentration-time curve and a historical etching endpoint.

[0079] Figure 7 is a flow chart of S104 in an embodiment of the present invention. Figure 7 As shown, S104 includes:

[0080] S301: Determine endpoint detection parameters according to the target element concentration in the target element concentration time curve and the historical etching endpoint.

[0081] In specific implementation, the endpoint detection parameter is [Y'-X end ] / X end; where Y' is the target element concentration, X end Etching the end point of history.

[0082] S302: Determine an endpoint detection threshold interval according to the etching endpoint layer.

[0083] Among them, the endpoint detection threshold interval can be within the range of ±10%; 10% is an example value, which is related to the material structure of the etching endpoint layer. According to the requirements for etching accuracy in the etching process, the endpoint detection threshold interval can be selected within the range of ±0.01%-±50%. Taking the film layer structure of the magnetic memory as an example, when the etching endpoint layer is in the CoFeB layer or MgO layer of the magnetic tunnel junction and other key film layers, the etching accuracy requirements are relatively high, and the endpoint detection threshold interval is ±1%-±5%; when the etching endpoint layer is in the bottom electrode layer of the magnetic tunnel junction (such as CuN), the etching accuracy requirements are relatively low and the film layer needs to be partially etched to ensure its electrode function. At this time, the endpoint detection threshold interval is ±50%.

[0084] S303: Determine the target etching endpoint according to the comparison result of the endpoint detection parameter and the endpoint detection threshold range.

[0085] In specific implementation, when the endpoint detection parameter is within the endpoint detection threshold interval, it can be considered that the target etching endpoint is reached, and the RF power supply is turned off to stop etching.

[0086] Figure 1 The execution subject of the etching endpoint detection method shown can be a computer. Figure 1 It can be seen from the process shown that the etching endpoint detection method of the embodiment of the present invention first obtains the etching endpoint element and the etching intermediate element according to the etching endpoint layer, and then collects the current element concentration-time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration-time curve of the etching intermediate element to obtain the target element concentration-time curve of the etching endpoint element with the corresponding historical element concentration-time curve, and finally determines the target etching endpoint according to the target element concentration in the target element concentration-time curve and the historical etching endpoint, which can meet the high-precision etching endpoint detection of samples with different film layer structures.

[0087] Based on the same inventive concept, an embodiment of the present invention further provides an etching endpoint detection device. Since the principle of solving the problem by the device is similar to that of the etching endpoint detection method, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be repeated.

[0088] Fig.12 is a structural block diagram of an etching endpoint detection device in an embodiment of the present invention. Fig.12 As shown, the etching endpoint detection device includes:

[0089] An etching element acquisition module is used to acquire etching endpoint elements and etching intermediate elements according to the etching endpoint layer;

[0090] The current element concentration time curve module is used to collect the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element;

[0091] A target element concentration time curve module is used to obtain a target element concentration time curve of the etching endpoint element according to the current element concentration time curve of the etching endpoint element and the corresponding historical element concentration time curve;

[0092] The target etching endpoint module is used to determine the target etching endpoint according to the target element concentration in the target element concentration time curve and the historical etching endpoint.

[0093] In one embodiment, it also includes:

[0094] The acquisition position module is used to determine the acquisition position according to the thickness of the etching endpoint layer.

[0095] In one embodiment, the target element concentration time curve module includes:

[0096] A conversion coefficient unit, used to determine a conversion coefficient based on a current element concentration time curve and a corresponding historical element concentration time curve;

[0097] The target element concentration-time curve unit is used to process the current element concentration-time curve of the etching endpoint element according to the conversion coefficient to obtain the target element concentration-time curve.

[0098] In one embodiment, the target etch endpoint module includes:

[0099] An endpoint detection parameter unit, used to determine endpoint detection parameters according to the target element concentration in the target element concentration time curve and the historical etching endpoint;

[0100] An endpoint detection threshold unit, used to determine an endpoint detection threshold according to the etching endpoint layer;

[0101] The target etching endpoint unit is used to determine the target etching endpoint according to the comparison result of the endpoint detection parameter and the endpoint detection threshold.

[0102] In summary, the etching endpoint detection device of the embodiment of the present invention first obtains the etching endpoint element and the etching intermediate element according to the etching endpoint layer, and then collects the current element concentration-time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration-time curve of the etching intermediate element to obtain the target element concentration-time curve of the etching endpoint element with the corresponding historical element concentration-time curve, and finally determines the target etching endpoint according to the target element concentration in the target element concentration-time curve and the historical etching endpoint, which can meet the high-precision etching endpoint detection of samples with different film layer structures.

[0103] The embodiment of the present invention also provides a specific implementation of a computer device capable of implementing all the steps in the etching endpoint detection method in the above embodiment. Fig.13 is a block diagram of a computer device in an embodiment of the present invention, see Fig.13 , the computer equipment specifically includes the following contents:

[0104] Processor (processor) 1301 and memory (memory) 1302 .

[0105] The processor 1301 is used to call the computer program in the memory 1302. When the processor executes the computer program, all the steps in the etching endpoint detection method in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0106] Obtaining etching endpoint elements and etching intermediate elements according to the etching endpoint layer;

[0107] Collecting the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element;

[0108] Obtaining a target element concentration time curve of the etching endpoint element according to a current element concentration time curve of the etching endpoint element and a corresponding historical element concentration time curve;

[0109] The target etching endpoint is determined based on the target element concentration in the target element concentration time curve and the historical etching endpoint.

[0110] In summary, the computer device of the embodiment of the present invention first obtains the etching endpoint element and the etching intermediate element according to the etching endpoint layer, and then collects the current element concentration-time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration-time curve of the etching intermediate element to obtain the target element concentration-time curve of the etching endpoint element with the corresponding historical element concentration-time curve, and finally determines the target etching endpoint according to the target element concentration in the target element concentration-time curve and the historical etching endpoint, which can meet the high-precision etching endpoint detection of samples with different film layer structures.

[0111] The embodiment of the present invention also provides a computer-readable storage medium capable of implementing all the steps in the etching endpoint detection method in the above embodiment. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, all the steps of the etching endpoint detection method in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0112] Obtaining etching endpoint elements and etching intermediate elements according to the etching endpoint layer;

[0113] Collecting the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element;

[0114] Obtaining a target element concentration time curve of the etching endpoint element according to a current element concentration time curve of the etching endpoint element and a corresponding historical element concentration time curve;

[0115] The target etching endpoint is determined based on the target element concentration in the target element concentration time curve and the historical etching endpoint.

[0116] In summary, the computer-readable storage medium of the embodiment of the present invention first obtains the etching endpoint element and the etching intermediate element according to the etching endpoint layer, and then collects the current element concentration-time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration-time curve of the etching intermediate element to obtain the target element concentration-time curve of the etching endpoint element with the corresponding historical element concentration-time curve, and finally determines the target etching endpoint according to the target element concentration in the target element concentration-time curve and the historical etching endpoint, which can meet the high-precision etching endpoint detection of samples with different film layer structures.

[0117] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0118] Those skilled in the art may also understand that the various illustrative logical blocks, units, and steps listed in the embodiments of the present invention may be implemented by electronic hardware, computer software, or a combination of the two. In order to clearly demonstrate the interchangeability of hardware and software, the various illustrative components, units, and steps described above have generally described their functions. Whether such functions are implemented by hardware or software depends on the specific application and the design requirements of the entire system. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementation should not be understood as exceeding the scope of protection of the embodiments of the present invention.

[0119] The various illustrative logic blocks, or units, or devices described in the embodiments of the present invention can be implemented or operated by a general-purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a field programmable gate array or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination of the above. The general-purpose processor can be a microprocessor, and optionally, the general-purpose processor can also be any conventional processor, controller, microcontroller or state machine. The processor can also be implemented by a combination of computing devices, such as a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a digital signal processor core, or any other similar configuration.

[0120] The steps of the method or algorithm described in the embodiments of the present invention can be directly embedded in hardware, a software module executed by a processor, or a combination of the two. The software module can be stored in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or other storage media of any form in the art. Exemplarily, the storage medium can be connected to the processor so that the processor can read information from the storage medium and can write information to the storage medium. Optionally, the storage medium can also be integrated into the processor. The processor and the storage medium can be arranged in an ASIC, and the ASIC can be arranged in a user terminal. Optionally, the processor and the storage medium can also be arranged in different components in the user terminal.

[0121] In one or more exemplary designs, the above functions described in the embodiments of the present invention can be implemented in hardware, software, firmware or any combination of the three. If implemented in software, these functions can be stored on a computer-readable medium, or transmitted in the form of one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media that facilitate the transfer of computer programs from one place to another. The storage medium can be any available medium that can be accessed by any general or special computer. For example, such computer-readable media can include but are not limited to RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store program codes in the form of instructions or data structures and other forms that can be read by general or special computers, or general or special processors. In addition, any connection can be appropriately defined as a computer-readable medium, for example, if the software is transmitted from a website site, server or other remote resource through a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wirelessly, such as infrared, wireless and microwave, it is also included in the defined computer-readable medium. The disk and disc include compact disk, laser disk, optical disk, DVD, floppy disk and blue-ray disk. Disks usually copy data magnetically, while discs usually copy data optically with lasers. The above combination can also be included in computer readable media.

Claims

1. A method for detecting an etching endpoint, characterized in that: include: Obtaining etching endpoint elements and etching intermediate elements according to the etching endpoint layer; Collecting the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element; Obtaining a target element concentration time curve of the etching endpoint element according to a current element concentration time curve of the etching endpoint element and a corresponding historical element concentration time curve; The target element concentration time curve of the etching endpoint element is obtained according to the current element concentration time curve of the etching endpoint element and the corresponding historical element concentration time curve, including: Determine a conversion coefficient according to the current element concentration time curve and the corresponding historical element concentration time curve; the conversion coefficient includes a slope k and a bias b; determine the slope k and the bias b according to the equations Xmin=k×Ymin+b and Xmax=k×Ymax+b; wherein the element concentration corresponding to the etching valley in the historical element concentration time curve is Xmin, and the element concentration corresponding to the etching peak is Xmax; the element concentration corresponding to the etching valley in the current element concentration time curve is Ymin, and the element concentration corresponding to the etching peak is Ymax; The current element concentration-time curve of the etching endpoint element is processed according to the conversion coefficient to obtain the target element concentration-time curve; specifically, the current element concentration-time curve is Y(t), and the target element concentration-time curve is Y'(t); the Y(t) curve is normalized to Y'(t), that is, Y'(t)=k×Y(t)+b; Determining a target etching endpoint according to a target element concentration in a target element concentration-time curve and a historical etching endpoint; Determining the target etching endpoint according to the target element concentration in the target element concentration time curve and the historical etching endpoint comprises: Determine the endpoint detection parameter according to the target element concentration in the target element concentration-time curve and the historical etching endpoint; the endpoint detection parameter is [Y'-Xend] / Xend; wherein Y' is the target element concentration, and Xend is the historical etching endpoint; by using multiple reference samples, adjusting different etching stop times tend, and cooperating with X-ray fluorescence analysis and X-ray diffraction thin film characterization to determine the composition of the film material on the surface of the corresponding sample, thereby screening out the optimal endpoint value (Xend, tend); Determining an endpoint detection threshold interval according to the etching endpoint layer; The target etching endpoint is determined according to a comparison result between the endpoint detection parameter and the endpoint detection threshold interval.

2. The etching endpoint detection method according to claim 1, characterized in that: Also includes: The collection position is determined according to the thickness of the etching endpoint layer.

3. An etching endpoint detection device, characterized in that: include: An etching element acquisition module is used to acquire etching endpoint elements and etching intermediate elements according to the etching endpoint layer; The current element concentration time curve module is used to collect the current element concentration time curve of the etching endpoint element at a preset collection position according to the etching peak of the current element concentration time curve of the etching intermediate element; A target element concentration time curve module is used to obtain a target element concentration time curve of the etching endpoint element according to the current element concentration time curve of the etching endpoint element and the corresponding historical element concentration time curve; The target element concentration time curve module includes: A conversion coefficient unit, used to determine a conversion coefficient according to the current element concentration time curve and the corresponding historical element concentration time curve; the conversion coefficient includes a slope k and a bias b; the slope k and the bias b are determined according to the equations Xmin=k×Ymin+b and Xmax=k×Ymax+b; wherein the element concentration corresponding to the etching valley in the historical element concentration time curve is Xmin, and the element concentration corresponding to the etching peak is Xmax; the element concentration corresponding to the etching valley in the current element concentration time curve is Ymin, and the element concentration corresponding to the etching peak is Ymax; The target element concentration time curve unit is used to process the current element concentration time curve of the etching endpoint element according to the conversion coefficient to obtain the target element concentration time curve; specifically, the current element concentration time curve is Y(t), and the target element concentration time curve is Y'(t); the Y(t) curve is normalized to Y'(t), that is, Y'(t)=k×Y(t)+b; A target etching endpoint module is used to determine a target etching endpoint according to a target element concentration in a target element concentration time curve and a historical etching endpoint; The target etching endpoint module includes: An endpoint detection parameter unit is used to determine an endpoint detection parameter according to the target element concentration in the target element concentration-time curve and the historical etching endpoint; the endpoint detection parameter is [Y'-Xend] / Xend; wherein Y' is the target element concentration, and Xend is the historical etching endpoint; by using multiple reference samples, adjusting different etching stop times tend, and cooperating with X-ray fluorescence analysis and X-ray diffraction thin film characterization to determine the composition of the film material on the surface of the corresponding sample, thereby screening out the optimal endpoint value (Xend, tend); An endpoint detection threshold unit, used to determine an endpoint detection threshold interval according to the etching endpoint layer; The target etching endpoint unit is used to determine the target etching endpoint according to the comparison result between the endpoint detection parameter and the endpoint detection threshold interval.

4. The etching endpoint detection device according to claim 3, characterized in that: Also includes: The acquisition position module is used to determine the acquisition position according to the thickness of the etching endpoint layer.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the etching endpoint detection method according to any one of claims 1 to 2 are implemented.

6. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the etching endpoint detection method according to any one of claims 1 to 2 are implemented.

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