Measurement calibration methods and methods for monitoring the stability of measurement equipment

Abstract

The present disclosure provides a measurement calibration method and a method for monitoring the stability of measurement equipment. The measurement calibration method includes: preparing a standard wafer having a surface covered with a dielectric film; pre-treating the standard wafer; obtaining a growth formula for an air molecule contamination layer on the surface of the pre-treated standard wafer; and calibrating the measured thickness of the dielectric film on the surface of a wafer to be tested, which is stored in the same environment as the standard wafer, based on the growth formula for the air molecule contamination layer, to obtain a calibrated thickness of the dielectric film on the surface of the wafer to be tested; the surfaces of the standard wafer and the wafer to be tested have the same type of dielectric film. The measurement calibration method dynamically monitors the adsorption and growth patterns of air molecule contamination on the wafer surface, and then uses these patterns to correct the wafer's dielectric film thickness, thereby achieving calibration of the dielectric film's measured thickness and improving the accuracy of obtaining the dielectric film thickness.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a measurement calibration method and a method for monitoring the stability of a measurement device. Background Art

[0002] Airborne molecular contamination (AMC) typically manifests as organic pollutants in the air adsorbing onto wafer surfaces, forming a contaminated film. AMC can severely impact semiconductor manufacturing processes and reduce yields. For example, AMC can cause semiconductor gate oxidation, thin film growth, and surface erosion during photolithography. Therefore, effectively monitoring AMC adsorption and growth on wafer surfaces is crucial for controlling semiconductor manufacturing processes and improving yields.

[0003] AMC refers to a series of pollutants contained in clean room air, which often appear in the form of gas, vapor or dust, mainly including inorganic compounds, organometallic compounds and organic compounds, such as sulfur dioxide (SO2), formaldehyde (HCHO), hydrogen sulfide (H2S), hydrogen fluoride (HF), ammonia (NH3), hexamethyldisilane (HMDS), etc. Summary of the Invention

[0004] The present disclosure aims to provide a measurement calibration method and a method for monitoring the stability of measurement equipment. By dynamically monitoring the growth patterns of air molecule contamination adsorbed on the wafer surface and calibrating the thickness of the wafer's dielectric film based on the patterns obtained from the monitoring, damage to the wafer caused by removing air molecule contamination before measurement can be avoided.

[0005] At least one embodiment of the present disclosure provides a measurement calibration method, the method comprising: preparing a standard wafer having a surface covered with a dielectric film; pre-treating the standard wafer; obtaining a growth formula for an air molecule contamination layer on the surface of the pre-treated standard wafer; and calibrating the measured thickness of the dielectric film on the surface of a wafer to be measured that has the same storage environment as the standard wafer based on the growth formula for the air molecule contamination layer to obtain a calibrated thickness of the dielectric film on the surface of the wafer to be measured; wherein the surfaces of the standard wafer and the wafer to be measured have the same type of dielectric film.

[0006] For example, in the measurement calibration method provided in at least one embodiment of the present disclosure, pre-processing the standard wafer includes: stabilizing the standard wafer; and / or cleaning the air molecule contamination layer on the surface of the standard wafer.

[0007] For example, in the measurement calibration method provided in at least one embodiment of the present disclosure, a growth formula of the air molecular contamination layer on the surface of the pretreated standard wafer is obtained, including: recording the thickness change of the dielectric film of the pretreated standard wafer, obtaining a growth curve of the thickness of the air molecular contamination layer on the surface of the pretreated standard wafer, and then obtaining the growth formula of the air molecular contamination layer.

[0008] For example, in the measurement and calibration method provided in at least one embodiment of the present disclosure, the thickness change of the dielectric film of the pre-treated standard wafer is recorded to obtain a growth curve of the thickness of the air molecule contamination layer on the surface of the pre-treated standard wafer, including: recording the initial thickness of the dielectric film of the pre-treated standard wafer; measuring the thickness of the dielectric film of the pre-treated standard wafer at different storage times to obtain multiple real-time thicknesses of the dielectric film of the pre-treated standard wafer, where the different storage times are equal time intervals or unequal time intervals; subtracting the initial thickness from the multiple real-time thicknesses to obtain the thickness of the air molecule contamination layer at different storage times; and obtaining a growth curve of the thickness of the air molecule contamination layer based on the thickness of the air molecule contamination layer at different storage times.

[0009] For example, in the measurement calibration method provided by at least one embodiment of the present disclosure, the growth formula of the air molecule contamination layer is expressed as: AMC=A*(1-e -k*t ), where AMC represents the thickness of the air pollution layer at time t, k=k des , C air Indicates the concentration of air molecules polluting in the environment, k abs Indicates the instantaneous adsorption rate of air molecule contamination on the wafer surface, k des Indicates the instantaneous desorption rate of air molecule contamination on the chip surface.

[0010] For example, in the measurement calibration method provided by at least one embodiment of the present disclosure, obtaining the growth formula of the air molecule contamination layer on the surface of the pre-treated standard wafer includes: fitting the growth curve of the thickness of the air molecule contamination layer to obtain A and k.

[0011] For example, in the measurement calibration method provided in at least one embodiment of the present disclosure, the measured thickness of the dielectric film of the wafer to be measured is calibrated according to the growth formula of the air molecule contamination layer, including: measuring the dielectric film of the wafer to be measured to obtain the measured thickness of the dielectric film of the wafer to be measured; calculating the thickness of the air molecule contamination layer on the surface of the wafer to be measured according to the growth formula of the air molecule contamination layer; and subtracting the thickness of the air molecule contamination layer on the surface of the wafer to be measured from the measured thickness of the dielectric film of the wafer to be measured to obtain the calibrated thickness of the dielectric film of the wafer to be measured.

[0012] For example, in the measurement calibration method provided in at least one embodiment of the present disclosure, stabilizing the standard chip includes: using heat treatment and oxidation treatment to stabilize the thickness of the dielectric film; cleaning the air molecule contamination layer on the surface of the standard chip includes: using heat treatment, solvent cleaning, and laser cleaning to remove the air molecule contamination layer.

[0013] At least one embodiment of the present disclosure further provides a method for monitoring the stability of a measurement device, comprising: obtaining a wafer to be measured, wherein a dielectric film of a specified thickness is provided on a surface of the wafer to be measured; using a measurement device to obtain a measured thickness of the dielectric film of the wafer to be measured; using a measurement calibration method provided by at least one embodiment of the present disclosure to calibrate the measured thickness of the dielectric film of the wafer to be measured to obtain a calibrated thickness of the dielectric film of the wafer to be measured; and evaluating the stability of the measurement device based on the calibrated thickness.

[0014] For example, in the method for monitoring the stability of a measuring device provided in at least one embodiment of the present disclosure, the stability of the measuring device is evaluated based on the calibration thickness, including: comparing the deviation between the calibration thickness and the specified thickness; if the deviation is not greater than a threshold, the stability of the measuring device is good; otherwise, the stability of the measuring device is poor.

[0015] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

[0016] The measurement calibration method disclosed in the present invention has the following beneficial effects:

[0017] This measurement and calibration method dynamically monitors the adsorption and growth patterns of air molecules on the wafer surface, then uses these patterns to correct the wafer's dielectric film thickness. This calibrates the measured dielectric film thickness and improves the accuracy of the obtained dielectric film thickness. Furthermore, this measurement and calibration method eliminates the need to clean the air molecule contamination layer on the wafer surface, effectively avoiding potential wafer damage from this cleaning process. Applying this disclosed measurement and calibration method to monitoring measurement equipment also effectively improves the accuracy of routine monitoring and calibration of the measurement equipment, thereby enhancing the long-term stability of the measurement equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Other features, objects and advantages of the present disclosure will become more apparent from a reading of the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0019] Figure 1 A schematic flow chart of a measurement calibration method provided in at least one embodiment of the present disclosure;

[0020] Figure 2 A schematic flowchart of step S112 provided for at least one embodiment of the present disclosure;

[0021] Figure 3 A schematic diagram of a method for measuring a growth curve of a thickness of an air molecule contamination layer on a pre-treated standard wafer surface according to at least one embodiment of the present disclosure;

[0022] Figure 4 is a schematic diagram of a growth curve of the thickness of an air molecule pollution layer;

[0023] Figure 5 A schematic diagram of calibrating the measured thickness of a dielectric film on a wafer to be measured according to at least one embodiment of the present disclosure;

[0024] Figure 6 A schematic diagram of a growth formula for an air molecule contamination layer obtained by fitting according to some embodiments of the present disclosure;

[0025] Figure 7 A schematic block diagram of a measurement and calibration system provided by at least one embodiment of the present disclosure;

[0026] Figure 8 A schematic block diagram of a measurement and calibration device provided in accordance with at least one embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0028] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by people with ordinary skills in the field to which this disclosure belongs. "First", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "one", "an" or "the" and similar words do not indicate a quantity limitation, but rather indicate the presence of at least one. "Include" or "comprising" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0029] Existing AMC detection mainly focuses on AMC detection on the chip surface and monitoring of AMC content in the air. The main technologies include ion chromatography (IC), gas chromatography-mass spectrometry (GC-MS), total reflection X-ray fluorescence (TXRF), etc. However, there is still a lack of effective means to dynamically monitor the AMC adsorption and growth process on the chip surface.

[0030] In wafer cassettes and cleanroom environments, AMCs continuously adsorb on the wafer surface, causing the measured dielectric film thickness to increase continuously. This in turn leads to inaccuracies in daily monitoring and calibration, and affects the long-term stability of the measurement equipment. Currently, wafer dielectric film thickness calibration primarily uses laser cleaning technology to remove AMCs before each monitoring session. However, laser cleaning can damage the wafer, causing changes in surface structural properties, which in turn affects the accuracy and stability of the dielectric film thickness.

[0031] In order to solve the above technical problems, at least one embodiment of the present disclosure provides a measurement calibration method, which includes: preparing a standard wafer with a dielectric film covered on its surface; pre-treating the standard wafer; obtaining a growth formula of an air molecule contamination layer on the surface of the pre-treated standard wafer; and calibrating the measured thickness of the dielectric film on the surface of a wafer to be measured that has the same storage environment as the standard wafer according to the growth formula of the air molecule contamination layer to obtain the calibrated thickness of the dielectric film on the surface of the wafer to be measured; wherein the surfaces of the standard wafer and the wafer to be measured have the same type of dielectric film.

[0032] The measurement and calibration method provided in the embodiments of the present disclosure dynamically monitors the adsorption and growth patterns of air molecule contamination on the wafer surface, and then continuously corrects the dielectric film thickness of the wafer based on these patterns. This can effectively avoid wafer damage caused by laser cleaning, thereby effectively improving the accuracy of daily monitoring and calibration of the measurement equipment and improving the long-term stability of the measurement equipment.

[0033] At least one embodiment of the present disclosure further provides a method for monitoring the stability of a measurement device and a measurement calibration system using the above-mentioned measurement calibration method.

[0034] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings, but the present disclosure is not limited to these specific embodiments.

[0035] Figure 1 A schematic flowchart of a measurement calibration method provided in at least one embodiment of the present disclosure.

[0036] like Figure 1As shown, the measurement calibration method includes the following steps S101 to S104.

[0037] Step S101: preparing a standard wafer with a surface covered with a dielectric film.

[0038] For example, the surface of a standard wafer has a dielectric film of a specified thickness. If the surface of the wafer has a silicon dioxide film of a specified thickness, a silicon dioxide wafer is formed. Taking silicon dioxide wafers as an example, silicon dioxide wafers can be prepared using different preparation processes, such as natural growth, water oxygen, thermal oxygen, CVD, etc. The film thickness includes but is not limited to Silica scales of equal thickness include but are not limited to 6, 8, 12 inches or other specifications.

[0039] Step S102: pre-processing the standard wafer.

[0040] For example, pre-treatment may include a stabilization treatment and / or an AMC removal process.

[0041] For example, in some embodiments of the present disclosure, step S101 may include: performing a stabilization process on the standard wafer; and / or performing a cleaning process on the air molecule contamination layer on the surface of the standard wafer.

[0042] For example, stabilization methods include, but are not limited to, heat treatment, oxidation treatment, and long-term storage. Stabilization treatment tends to stop the natural oxidation of the dielectric film on the wafer, stabilizing the thickness of the dielectric film. Heat treatment utilizes conventional heating equipment (such as an oven or heating table), allowing the dielectric film thickness to reach a stable state in a relatively short period of time.

[0043] For example, AMC removal processes / cleaning treatments include but are not limited to heat treatment, solvent cleaning, laser cleaning, and other technologies. Heat treatment includes but is not limited to different treatment temperatures (such as 200°C, 230°C, 260°C, 300°C, etc.), different heating equipment (such as ovens, heating tables, etc.), and different heat treatment times (1 min, 3 min, 5 min, 7 min, 10 min, etc.). Solvent cleaning includes but is not limited to different solvents, such as isopropyl alcohol, ethanol, acetone, etc. Laser cleaning includes but is not limited to laser types (nanosecond pulse, picosecond pulse laser, etc.) and cleaning times (1 s, 3 s, 5 s, 7 s, etc.).

[0044] The wafer can be pre-processed through stabilization and AMC removal processes to ensure the consistency of the wafer's initial state.

[0045] Step S103: obtaining a growth formula of the air molecule contamination layer on the pre-treated standard wafer surface.

[0046] Step S104: Calibrate the measured thickness of the dielectric film on the surface of the wafer to be tested that has the same storage environment as the standard wafer according to the growth formula of the air molecule contamination layer to obtain the calibrated thickness of the dielectric film on the surface of the wafer to be tested.

[0047] For example, the surfaces of the standard wafer and the wafer to be tested have the same type of dielectric film. The wafer to be tested can be a standard wafer or a non-standard wafer having the same type of dielectric film.

[0048] For example, in some embodiments of the present disclosure, step S103 may include step S112: recording the thickness change of the dielectric film of the pre-treated standard wafer, obtaining a growth curve of the thickness of the air molecular contamination layer on the surface of the pre-treated standard wafer, and then obtaining a growth formula for the air molecular contamination layer.

[0049] For example, in some embodiments of the present disclosure, the growth formula of the air molecule contamination layer is expressed as: AMC=A*(1-e -k*t ), where AMC represents the thickness of the air pollution layer at time t, C air Indicates the concentration of air molecules polluting in the environment, k abs Indicates the instantaneous adsorption rate of air molecule contamination on the wafer surface, k des Indicates the instantaneous desorption rate of air molecule contamination on the chip surface.

[0050] The growth formula can be obtained by obtaining A and k in the growth formula of the air molecular contamination layer. For example, A and k can be obtained by fitting the growth curve of the thickness of the air molecular contamination layer.

[0051] Figure 2 A schematic flowchart of step S112 is provided for at least one embodiment of the present disclosure.

[0052] like Figure 2 As shown, step S112 includes the following steps S201 to S204.

[0053] Step S201: recording the initial thickness of the dielectric film of the pre-processed standard wafer.

[0054] For example, the initial thickness of the dielectric film of the pre-treated standard wafer is the dielectric film thickness of the pre-treated standard wafer stored for 0 days.

[0055] Step S202 : measuring the thickness of the dielectric film of the pre-processed standard wafer at different storage times to obtain a plurality of real-time thicknesses of the dielectric film of the pre-processed standard wafer.

[0056] Over varying storage times, the wafer surface will continuously adsorb AMC, causing the dielectric film thickness to grow. The real-time thickness of the dielectric film on a standard wafer after pretreatment will continue to increase over time. It's important to note that when selecting storage times, real-time thickness data should be collected at as many different time points as possible until the growth of airborne contamination stabilizes, meaning the real-time thickness is essentially stable.

[0057] For example, the different storage times are equal time intervals or unequal time intervals.

[0058] Step S203: subtracting the initial thickness from the multiple real-time thicknesses to obtain the thickness of the air molecule pollution layer at different storage times.

[0059] Step S204: obtaining a growth curve of the thickness of the air molecular contamination layer according to the thickness of the air molecular contamination layer at different storage times.

[0060] The thickness growth curve of the air molecule contamination layer on the surface of the pre-treated standard wafer can be calculated by the difference method. The measurement method is as follows: Figure 3 As shown. Figure 3 In the figure, the horizontal axis is time, the vertical axis is the thickness of the dielectric film of the standard wafer after pretreatment, the dotted line represents the initial thickness of the dielectric film of the standard wafer after pretreatment, and the solid line represents multiple real-time thicknesses of the dielectric film of the standard wafer after pretreatment. The real-time thickness is subtracted from the initial thickness to obtain the growth curve of the thickness of the air molecule contamination layer. The growth curve is shown in FIG. Figure 4 As shown. Figure 4 In the figure, the horizontal axis is time, the vertical axis is the thickness of the air molecular pollution layer, the period from 0 to T4 is the growth period of the air molecular pollution layer, and the period greater than T4 is the stable period of the air molecular pollution layer.

[0061] For example, the dielectric film thickness can be measured using measuring equipment such as ellipsometry, reflectivity film thickness measuring equipment, and the present disclosure does not impose any restrictions on this.

[0062] For example, in some embodiments of the present disclosure, step S104 may include: measuring the dielectric film of the wafer to be tested to obtain a measured thickness of the dielectric film of the wafer to be tested; calculating the thickness of the air molecular contamination layer on the surface of the wafer to be tested according to a growth formula of the air molecular contamination layer; and subtracting the thickness of the air molecular contamination layer on the surface of the wafer to be tested from the measured thickness of the dielectric film of the wafer to be tested to obtain a calibrated thickness of the dielectric film of the wafer to be tested.

[0063] Figure 5 The diagram is a schematic diagram of calibrating the thickness of the dielectric film on the wafer to be tested. Figure 5As shown, the solid line represents the measured thickness of the dielectric film of the wafer to be tested, the dotted line represents the thickness of the air molecular contamination layer calculated according to the growth formula of the air molecular contamination layer, and the dotted solid line represents the calibrated thickness of the dielectric film of the wafer to be tested.

[0064] By dynamically monitoring the AMC growth curve, the AMC growth formula is obtained. The dielectric film thickness of the wafer to be measured is then corrected using the AMC growth formula, thereby achieving calibration of the measured dielectric film thickness and improving the accuracy of the obtained dielectric film thickness. At the same time, this measurement and calibration method does not require cleaning the surface air molecule contamination layer of the wafer to be measured, effectively avoiding possible wafer damage caused by the cleaning process.

[0065] At least one embodiment of the present disclosure further provides a method for monitoring the stability of a measurement device, comprising: obtaining a wafer to be measured, wherein a surface of the wafer to be measured has a dielectric film of a specified thickness; using a measurement device to obtain the measured thickness of the dielectric film of the wafer to be measured; using the above-mentioned measurement calibration method to calibrate the measured thickness of the dielectric film of the wafer to be measured to obtain the calibrated thickness of the dielectric film of the wafer to be measured; and evaluating the stability of the measurement device based on the calibrated thickness.

[0066] For example, in some embodiments of the present disclosure, evaluating the stability of the measuring device based on the calibration thickness may include: comparing the deviation between the calibration thickness and the specified thickness; if the deviation is not greater than a threshold, the stability of the measuring device is good; otherwise, the stability of the measuring device is poor.

[0067] Applying the measurement calibration method in the embodiment of the present disclosure to monitoring measurement equipment effectively improves the accuracy of daily monitoring and calibration of the measurement equipment, thereby improving the long-term stability of the measurement equipment.

[0068] The following uses an example to specifically illustrate the measurement calibration method and the method for monitoring the stability of a measurement device provided by the embodiments of the present disclosure.

[0069] First, there will be The standard wafers with dielectric films are stored for one year, so that the natural oxidation of the dielectric film on the surface of the standard wafer tends to stop, the film thickness of the dielectric film is stabilized, and the stabilization treatment is completed.

[0070] The standard wafers are then heat-treated to remove the airborne contamination layer from their surfaces. Heat treatment conditions are 230°C for 3-6 minutes to complete the removal of the airborne contamination layer. Ellipsometry is used to measure the initial thickness of the dielectric film on the treated standard wafers. The pre-treated standard wafers are then stored in a wafer cassette.

[0071] For example, for standard wafers with thicker dielectric films, heat treatment can be directly used to simultaneously stabilize the dielectric film thickness and remove the air molecule layer.

[0072] Then, the real-time thickness of the dielectric film on the pre-treated standard wafers at different storage times (e.g., 0 / 1 / 2 / 4 / 8 / 16 / 32 / 64 / 128 days) was measured using ellipsometry (Table 1). The thickness of the air molecular contamination layer at different storage times was calculated using the difference method (Table 1), and the growth formula for the thickness of the air molecular contamination layer was obtained by fitting ( Figure 6 ),exist Figure 6 In the figure, the solid line represents the thickness of AMC changing with time, i.e., the AMC growth curve, and the dotted line represents the AMC growth formula obtained by mathematical fitting: AMC = 3.4*(1-e -0.1*t ) corresponding to the curve.

[0073] Table 1

[0074]

[0075] The derivation process of the above growth formula is as follows:

[0076] During the deposition process of AMC on the wafer surface, adsorption and desorption occur simultaneously. The instantaneous surface deposition density can be expressed as:

[0077]

[0078] Among them C dep is the surface deposition density (ng / cm 2 ), C abs is the surface adsorption density (ng / cm 2 ), C des is the surface desorption density (ng / cm 2 ). In general, it can be considered that the AMC concentration in the environment (C air , μg / m 3 ) is relatively stable, and the instantaneous adsorption rate of air molecule pollution on the chip surface is k abs Same as C air The correlation is a fixed constant, and the instantaneous AMC adsorption density on the wafer surface can be expressed as:

[0079]

[0080] The instantaneous desorption rate k of air molecule contamination on the chip surface de s is the same as the deposition density C on the wafer surface de p, and its instantaneous desorption density can be expressed as:

[0081]

[0082] It can be deduced that:

[0083]

[0084] Then the AMC surface deposition density at time t is obtained as:

[0085]

[0086] The above formula can be further simplified as:

[0087] C dep (t) = A*[1-e -k*t ] Formula 6

[0088] Assuming that the thickness of the dielectric film after AMC deposition is positively correlated with its surface deposition density, the film thickness change during AMC growth can be expressed using the molecular deposition kinetics formula, namely:

[0089] AMC=A*(1-e -k*t )

[0090] By simply measuring the AMC growth curve and obtaining A and k, we can obtain the approximate AMC growth formula.

[0091] Then, select a wafer with the same storage environment as the pre-processed standard wafer. For the wafer with dielectric film, the thickness of the dielectric film is measured using ellipsometry. The thickness of the air molecular contamination layer on the surface of the wafer is calculated according to the growth formula of the air molecular contamination layer. The thickness of the dielectric film on the wafer is calibrated using the difference method. The calibrated thickness is shown in Table 2.

[0092] Table 2

[0093]

[0094] Among them, the 1st and 2nd rows are the data of the measured thickness of the wafer under test changing with time, the 3rd row is the AMC thickness obtained according to the AMC growth formula, and the calibrated thickness of the dielectric film of the wafer under test is obtained by subtracting the data in the 2nd row from the data in the 3rd row.

[0095] As shown in Table 2, the measured thickness at the three time points in row 2 gradually increases. The dielectric film thickness growth is primarily due to AMC growth, resulting in variations in the dielectric film thickness. However, the calibrated thickness in row 4 eliminates the influence of AMC, resulting in relatively stable thickness (fluctuating within a very small range). This demonstrates that the measurement calibration method disclosed herein effectively improves the measurement accuracy of dielectric film thickness on the wafer surface under test without performing AMC removal on the wafer under test. Directly calibrating the metrology equipment using measured thickness would introduce additional errors caused by AMC growth, affecting calibration accuracy and, in turn, the measurement accuracy of the metrology equipment. In contrast, the method disclosed herein uses calibrated thickness to calibrate the metrology equipment, eliminating the influence of AMC and improving calibration accuracy, thereby ensuring the measurement accuracy of the metrology equipment. While Table 2 only provides partial data, in practical applications, it can achieve good calibration results over relatively long periods of time. Furthermore, the method disclosed herein avoids damage to the wafer under test caused by the AMC removal process in the prior art. Using this measurement calibration method to monitor metrology equipment improves calibration and monitoring accuracy during long-term calibration and monitoring of metrology equipment stability.

[0096] Figure 7 A measurement calibration system 700 provided by at least one embodiment of the present disclosure is shown. The measurement calibration system 700 can be used to perform Figure 1 The measurement calibration method shown.

[0097] like Figure 7 As shown, the measurement calibration system 700 may include a pre-processing module 701 , a growth formula calculation module 702 and a calibration module 703 .

[0098] The pre-processing module 701 is configured to pre-process the standard wafer to obtain a processed standard wafer;

[0099] The growth formula calculation module 702 is configured to obtain a growth formula of the air molecule contamination layer on the surface of the pre-treated standard wafer;

[0100] The calibration module 703 is configured to calibrate the measured thickness of the dielectric film of the wafer under test that has the same storage environment as the pre-processed standard wafer according to the growth formula of the air molecule contamination layer.

[0101] For example, the measurement and calibration system 700 may be implemented using hardware, software, firmware, or any feasible combination thereof, and the present disclosure is not limited thereto.

[0102] The technical effects of the measurement and calibration system 700 are the same as those of the above-mentioned measurement and calibration method, and are not described in detail here.

[0103] Figure 8Schematic block diagram of a measurement and calibration device 800 provided in some embodiments of the present disclosure. Figure 8 As shown, the measurement and calibration device 800 includes a processor 810 and a memory 820. The memory 820 is used to store computer-executable instructions (e.g., one or more computer program modules). The processor 810 is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor 810, one or more steps of the measurement and calibration method described above are performed. The memory 820 and the processor 810 can be interconnected via a bus system and / or other form of connection mechanism (not shown).

[0104] For example, the processor 810 may be a central processing unit (CPU), a graphics processing unit (GPU), or other processing unit with data processing capabilities and / or program execution capabilities. For example, the central processing unit (CPU) may be an X86 or ARM architecture. The processor 810 may be a general-purpose processor or a dedicated processor, and may control other components in the measurement and calibration device 800 to perform desired functions.

[0105] For example, the memory 820 may include any combination of one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Non-volatile memory may include, for example, read-only memory (ROM), a hard disk, an erasable programmable read-only memory (EPROM), a portable compact disk read-only memory (CD-ROM), a USB memory, a flash memory, etc. One or more computer program modules may be stored on the computer-readable storage medium, and the processor 810 may execute one or more computer program modules to implement various functions of the measurement and calibration device 800. Various applications and various data, as well as various data used and / or generated by the applications, may also be stored in the computer-readable storage medium.

[0106] It should be noted that, in the embodiment of the present disclosure, the specific functions and technical effects of the measurement and calibration device 800 can be referred to the above description of the measurement and calibration method, which will not be repeated here.

[0107] For example, according to embodiments of the present disclosure, the measurement calibration method described above can be implemented as a computer software program. For example, embodiments of the present disclosure include a computer program product comprising a computer program borne on a non-transitory computer-readable medium, the computer program including program code for executing the measurement calibration method described above. When executed by a processor, the computer program can implement the functions defined in the measurement calibration method provided in embodiments of the present disclosure.

[0108] There are a few points to note:

[0109] (1) The drawings of the embodiments of the present disclosure only relate to the structures involved in the embodiments of the present disclosure. Other structures may refer to conventional designs.

[0110] (2) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to form new embodiments.

[0111] The above description is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. The protection scope of the present disclosure shall be based on the protection scope of the claims.

Claims

1. A measurement calibration method, characterized in that: include: Preparation of standard wafers with dielectric film covering the surface; Pre-processing the standard wafer; Obtaining a growth formula for an air molecule contamination layer on a standard wafer surface after pretreatment; Calibrate the measured thickness of the dielectric film on the surface of a wafer to be tested that has the same storage environment as the standard wafer according to the growth formula of the air molecule contamination layer to obtain a calibrated thickness of the dielectric film on the surface of the wafer to be tested; The surfaces of the standard wafer and the wafer to be tested have the same type of dielectric film, and the wafer to be tested and the standard wafer are not the same wafer.

2. The measurement calibration method according to claim 1, wherein: The pre-processing of the standard wafer comprises: performing a stabilization process on the standard wafer; and / or, The air molecule contamination layer on the surface of the standard wafer is cleaned.

3. The measurement calibration method according to claim 1, wherein: The growth formula of the air molecular contamination layer on the surface of the pre-treated standard wafer is obtained, including: The thickness change of the dielectric film of the pre-treated standard wafer is recorded to obtain a thickness growth curve of the air molecule contamination layer on the surface of the pre-treated standard wafer, and then obtain a growth formula of the air molecule contamination layer.

4. The measurement calibration method according to claim 3, wherein: Recording the thickness change of the dielectric film of the pretreated standard wafer to obtain a growth curve of the thickness of the air molecule contamination layer on the surface of the pretreated standard wafer includes: Recording the initial thickness of the dielectric film of the pre-processed standard wafer; Measuring the thickness of the dielectric film of the pre-processed standard wafer at different storage times to obtain multiple real-time thicknesses of the dielectric film of the pre-processed standard wafer, wherein the different storage times are equal time intervals or unequal time intervals; Subtracting the initial thickness from the multiple real-time thicknesses to obtain the thickness of the air molecule pollution layer at different storage times; A growth curve of the thickness of the air molecule contamination layer is obtained according to the thickness of the air molecule contamination layer at different storage times.

5. The measurement calibration method according to claim 3 or 4, characterized in that: The growth formula of the air molecule contamination layer is expressed as: AMC=A*(1-e -k*t ), where AMC represents the thickness of the air pollution layer at time t, k=k des , C air Indicates the concentration of air molecules polluting in the environment, k abs Indicates the instantaneous adsorption rate of air molecule contamination on the wafer surface, k des Indicates the instantaneous desorption rate of air molecule contamination on the chip surface.

6. The measurement calibration method according to claim 5, characterized in that: Obtaining a growth formula for the air molecule contamination layer on the pre-treated standard wafer surface includes: A and k are obtained by fitting a growth curve of the thickness of the air molecule pollution layer.

7. The measurement calibration method according to claim 1, wherein: Calibrate the measured thickness of the dielectric film of the wafer to be tested according to the growth formula of the air molecule contamination layer, including: Measuring the dielectric film of the wafer to be tested to obtain a measured thickness of the dielectric film of the wafer to be tested; Calculating the thickness of the air molecule contamination layer on the surface of the wafer to be tested according to a growth formula of the air molecule contamination layer; The measured thickness of the dielectric film of the wafer to be tested is subtracted from the thickness of the air molecule contamination layer on the surface of the wafer to be tested to obtain a calibrated thickness of the dielectric film of the wafer to be tested.

8. The measurement calibration method according to claim 2, wherein: The stabilization treatment of the standard wafer includes: using heat treatment and oxidation treatment to stabilize the thickness of the dielectric film; The cleaning process of the air molecule contamination layer on the surface of the standard wafer includes: removing the air molecule contamination layer by heat treatment, solvent cleaning, or laser cleaning.

9. A method for monitoring the stability of a measuring device, characterized in that: The method comprises: Obtaining a wafer to be tested, wherein a dielectric film of a specified thickness is formed on a surface of the wafer to be tested; Using the measuring device, obtaining the measured thickness of the dielectric film of the wafer to be measured; Adopting the measurement calibration method according to any one of claims 1 to 8, calibrating the measured thickness of the dielectric film of the wafer to be measured to obtain the calibrated thickness of the dielectric film of the wafer to be measured; Based on the calibrated thickness, the stability of the metrology device is evaluated.

10. The method for monitoring the stability of a measuring device according to claim 9, wherein: The evaluating the stability of the measuring device based on the calibration thickness includes: The deviation between the calibrated thickness and the specified thickness is compared. If the deviation is not greater than a threshold, the stability of the measuring device is good; otherwise, the stability of the measuring device is poor.

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