Ion implantation depth measuring method and device
By employing a self-verified measurement process based on etching rate variations, and utilizing conventional etching equipment and an ellipsometry to measure ion implantation junction depth, the high cost and low efficiency issues of existing technologies are resolved. This enables low-cost, high-efficiency junction depth measurement, adaptable to different process conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WESTLAKE UNIV
- Filing Date
- 2025-12-16
- Publication Date
- 2026-05-08
AI Technical Summary
Existing technologies for measuring ion implantation junction depth are costly, inefficient, and rely on expensive, large-scale analytical instruments, making it difficult to meet the rapid, high-throughput detection requirements of modern semiconductor manufacturing.
By detecting changes in etching rate caused by ion implantation and utilizing differences in etching behavior, a self-verifying measurement process is constructed. Measurements are performed using conventional etching equipment and an ellipsometry, avoiding reliance on expensive equipment.
It enables low-cost, high-efficiency measurement of ion implantation junction depth, ensuring the safety and reliability of the measurement, adapting to different process conditions, and eliminating dependence on expensive equipment such as TOF-SIMS.
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Figure CN122003132A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a method and apparatus for measuring ion implantation depth. Background Technology
[0002] In the semiconductor manufacturing field, ion implantation technology is a key process for achieving device doping. It precisely controls the electrical properties of semiconductor materials by implanting high-energy ions. The depth of ion implantation, or junction depth, is one of the core parameters determining device performance, and effective and reliable monitoring of the junction depth is a necessary step to ensure product yield and performance.
[0003] Currently, the industry primarily relies on time-of-flight secondary ion mass spectrometry (TOF-SIMS) to measure the depth of ion implanted junctions. This technique uses an ion beam to sputter a sample and performs mass spectrometry analysis on the emitted secondary ions, enabling high-precision characterization of the concentration distribution of dopants along the depth direction, thereby determining the junction depth.
[0004] However, this mainstream technology has significant limitations. First, the TOF-SIMS equipment itself and its subsequent maintenance costs are extremely high, making its application difficult and hindering its widespread adoption in production line monitoring. Second, achieving excellent depth resolution and detection sensitivity typically requires a long measurement time per cycle, failing to meet the demands of modern semiconductor manufacturing for rapid, high-throughput detection. Furthermore, this technology places stringent requirements on the operating environment and the expertise of the personnel. These factors collectively contribute to the high cost, limited efficiency, and heavy reliance on specific large-scale analytical instruments for current ion implantation junction depth measurement methods. Therefore, there is an urgent need to research an alternative measurement scheme that combines low cost and high efficiency. Summary of the Invention
[0005] In view of this, this application provides an ion implantation depth measurement method and apparatus, which measures junction depth by detecting the change in etching rate caused by ion implantation, thus solving the problems of high cost and low efficiency of traditional technologies.
[0006] Specifically, this application is implemented through the following technical solution:
[0007] A first aspect of this application provides a method for measuring ion implantation depth, the method comprising:
[0008] The first duration is determined based on the pre-measured thickness of the dielectric layer, the currently selected etching process, and the pre-determined relationship between the etching process and the etching rate of the dielectric layer.
[0009] The first etching duration and the second etching duration are determined based on the first duration; the first etching duration is less than the second etching duration; both the first etching duration and the second etching duration are less than the first duration;
[0010] The dielectric layer that has not been treated by ion implantation is etched according to the currently selected etching process for the second etching duration, and the first etching rate of the dielectric layer is determined based on the first thickness change value of the dielectric layer during the etching process and the second etching duration.
[0011] According to the currently selected etching process, the dielectric layer treated by the ion implantation process is etched for the first etching time and the second etching time, respectively, and the thickness change of the dielectric layer at each etching time is determined.
[0012] Based on the thickness variation of the dielectric layer at various etching durations, it is determined whether the etching process corresponding to each etching duration corresponds to two different types of etching; the two different types of etching are etching only the injection layer and etching both the injection layer and the dielectric layer simultaneously.
[0013] If so, the thickness of the injection layer is determined based on the first etching rate and the thickness change of the dielectric layer at each etching duration; otherwise, the step of determining the first etching duration and the second etching duration based on the first duration is executed again.
[0014] A second aspect of this application provides an ion implantation depth measurement device, the device comprising a determination module, an etching module, and a processing module;
[0015] The determining module is used to determine the first duration based on the pre-measured thickness of the dielectric layer, the currently selected etching process, and the pre-determined relationship between the etching process and the etching rate of the dielectric layer.
[0016] The determining module is further configured to determine a first etching duration and a second etching duration based on the first duration; the first etching duration is less than the second etching duration; and both the first etching duration and the second etching duration are less than the first duration.
[0017] The etching module is used to etch the dielectric layer that has not been treated by the ion implantation process for the second etching time according to the currently selected etching process, and to determine the first etching rate of the dielectric layer based on the first thickness change value of the dielectric layer during the etching process and the second etching time.
[0018] The etching module is further configured to etch the dielectric layer treated by the ion implantation process for the first etching time and the second etching time respectively according to the currently selected etching process, and determine the thickness change of the dielectric layer at each etching time;
[0019] The processing module is used to determine whether the etching process corresponding to each etching duration corresponds to two different types of etching based on the thickness change of the dielectric layer at each etching duration; the two different types of etching are etching only the injection layer and etching both the injection layer and the dielectric layer simultaneously.
[0020] If so, the thickness of the injection layer is determined based on the first etching rate and the thickness change of the dielectric layer at each etching duration; otherwise, the step of determining the first etching duration and the second etching duration based on the first duration is executed again.
[0021] The ion implantation depth measurement method and apparatus provided in this application effectively eliminate reliance on traditional high-cost analytical instruments by constructing a self-verifying measurement process based on differences in etching behavior. Specifically, by pre-determining a first etching duration as a safety boundary, the method ensures that the entire etching measurement process will not damage the substrate, thus guaranteeing its safety and reliability. By setting and utilizing two parameters—the first etching duration and the second etching duration—the method successfully acquires thickness change data reflecting the sequential etching of the implanted layer and the unimplanted dielectric layer, providing input for subsequent calculations. Furthermore, by determining whether the etching process corresponds to two different types of etching in a verification step, and introducing an iterative adjustment mechanism for cases where the determination is negative, the success rate and adaptability of the measurement method under different process conditions are improved. Ultimately, this achieves effective measurement of the implanted layer thickness without the need for complex component analysis equipment. Attached Figure Description
[0022] Figure 1 A flowchart of an embodiment of the ion implantation depth measurement method provided in this application;
[0023] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the ion implantation depth measurement device provided in this application. Detailed Implementation
[0024] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.
[0025] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used herein are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.
[0026] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."
[0027] The following specific embodiments are given to illustrate the technical solution of this application in detail.
[0028] Example 1
[0029] Figure 1 This is a flowchart of an embodiment of the ion implantation depth measurement method provided in this application. Please refer to... Figure 1 The method provided in this embodiment is used to measure the thickness of an implanted layer formed after ion implantation of a dielectric layer; the dielectric layer is formed on a substrate; the method may include:
[0030] It's important to note that ion implantation is a crucial doping technique in semiconductor manufacturing. It involves bombarding the surface of semiconductor materials with high-energy impurity ions, thereby altering their electrical properties. The depth of ion implantation, or junction depth, is one of the core parameters affecting device performance and requires precise monitoring. Specifically, implanted ions collide with the material's crystal lattice, causing damage to the crystal structure within the implanted region (such as lattice disorder or amorphization), thus forming an implanted layer. This damage to the crystal structure significantly alters the etching rate of the implanted layer in a specific etching process. Therefore, the difference in etching rate can be used to indirectly measure the junction depth, replacing traditional methods that rely on expensive and time-consuming large analytical equipment.
[0031] Specifically, in this embodiment, the substrate is typically a semiconductor substrate, such as a silicon substrate, and the dielectric layer is a non-conductive thin film formed on the substrate, such as a silicon dioxide (SiO2) layer or a silicon nitride layer. Preferably, this embodiment uses a silicon substrate and a silicon dioxide dielectric layer grown on it by a thermal oxidation process as an example, because this material system is widely used in the semiconductor industry, has good uniformity in preparation, and is beneficial for obtaining stable and reliable measurement results.
[0032] Before proceeding with subsequent measurement steps, sample preparation is required to prepare test pieces suitable for ion implantation and subsequent etching. First, a wafer with the dielectric layer formed on its surface is provided. Then, the wafer is diced into multiple sample pieces of suitable size for processing. Finally, at least one of the sample pieces is mounted on a support substrate to facilitate processing in an ion implantation apparatus.
[0033] In a practical implementation, for example, a 4-inch silicon wafer with a 2μm thick silicon dioxide layer thermally grown on its surface can be provided. The wafer is then cut into 10mm×10mm pieces using a precision dicing machine. After the pieces are cleaned, they are attached to a 6-inch silicon substrate. The substrate is then placed on the sample stage of an ion implanter for implantation.
[0034] S101. Determine the first duration based on the pre-measured thickness of the dielectric layer, the currently selected etching process, and the pre-determined relationship between the etching process and the etching rate of the dielectric layer.
[0035] It should be noted that the initial thickness of the dielectric layer can be measured after the sample preparation is completed. Preferably, an ellipsometer can be used for measurement, which has the advantages of being non-destructive and highly accurate, and is a commonly used and readily available metrology tool in semiconductor R&D and production lines.
[0036] It should also be noted that, in this embodiment, the HF vapor phase etching process is preferably used. Some parameters involved in this process include the flow rate of hydrogen fluoride (HF) gas, the flow rate of ethanol (EtOH) gas, the flow rate of nitrogen (N2) gas, and the etching chamber pressure. The introduction of EtOH is used to adjust the etching selectivity and suppress side reactions; N2 serves as a carrier gas and dilution gas; and the chamber pressure is used to balance the etching rate and uniformity.
[0037] The predetermined relationship between the etching process and the etching rate of the dielectric layer refers to the etching rate established through prior experiments or process knowledge, under the aforementioned etching process conditions for a raw dielectric layer that has not undergone ion implantation. This rate is a relatively fixed value, which can be obtained by etching an unimplanted sample with this etching process for a known period of time, and then measuring the thickness change before and after etching using an ellipsometry, and calculating (thickness change value / etching time).
[0038] Furthermore, the first etching duration is a theoretical upper limit set for safety based on the current etching process parameters. Its value is approximately equal to the time required to completely etch away the entire original dielectric layer. Specifically, based on the pre-measured initial thickness of the dielectric layer and the known etching rate of the dielectric layer under the current etching process, it can be estimated as: first duration ≈ initial thickness / etching rate. Further, to ensure safety, this theoretical value can be multiplied by a safety factor less than 1. By determining the first etching duration, all subsequent etching experiments (first etching duration, second etching duration) should be much shorter than this value, thereby ensuring that the etching does not reach the underlying substrate and ensuring the validity and safety of the measurement.
[0039] S102. Determine the first etching duration and the second etching duration based on the first duration; the first etching duration is less than the second etching duration; both the first etching duration and the second etching duration are less than the first duration.
[0040] It should be noted that both the first and second etching durations are determined based on the established first duration to ensure the safety and effectiveness of the experimental process. In practice, the first etching duration can be selected based on a pre-estimated thickness of the implanted layer or through experience. Specifically, the first etching duration should be set to a relatively short time, aiming to ensure that the etching process occurs exactly or nearly completely within the modified layer (i.e., the implanted layer) formed by ion implantation; while the second etching duration must be set to a sufficiently long time to ensure that the etching process has completely penetrated the entire implanted layer and etched the underlying unmodified original dielectric layer.
[0041] By setting a first etching duration and a second etching duration, two different etching profiles can be created on the ion-implanted dielectric layer. Ideally, the state at the first etching duration corresponds primarily or entirely to the implanted layer, where the etching rate is faster. The state at the second etching duration corresponds to a composite result of the implanted layer undergoing rapid etching and the subsequent slow etching of the original dielectric layer. The thickness variation data corresponding to these two states provides a physical basis for subsequently identifying and separating the two different etching rates.
[0042] S103. Etch the dielectric layer that has not been treated by ion implantation process according to the currently selected etching process for the second etching duration, and determine the first etching rate of the dielectric layer based on the first thickness change value of the dielectric layer during the etching process and the second etching duration.
[0043] It should be noted that choosing to use a longer second etching duration to etch the un-implanted sample can produce a sufficiently large thickness change value, thereby effectively reducing the relative error of a single thickness measurement and making the calculated etching rate more accurate and reliable.
[0044] In practice, a dielectric layer sample without ion implantation is selected, and etched for a duration equal to the second etching time using the same etching process as in subsequent experiments. Before and after etching, the thickness of the dielectric layer is precisely measured using an ellipsometry. Subtracting the thickness after etching from the thickness before etching yields the first thickness change. Subsequently, dividing the first thickness change by the second etching time calculates the first etching rate. The first etching rate characterizes the inherent etching properties of the unimplanted region and will be compared with the etching behavior of the ion-implanted region in subsequent calculations.
[0045] S104. The dielectric layer treated by the ion implantation process is etched for the first etching time and the second etching time according to the currently selected etching process, and the thickness change of the dielectric layer under each etching time is determined.
[0046] It should be noted that the ion implantation process uses a wide range of ion types, including but not limited to argon ions, boron ions, phosphorus ions, arsenic ions, oxygen ions, nitrogen ions, magnesium ions, and aluminum ions. Preferably, this embodiment uses argon ions as an example. The advantage of choosing inert gas ions such as argon ions is that they do not participate in electrical doping; they primarily cause purely physical structural damage through collisions with the crystal lattice. This helps to more clearly study and prove the principle that crystal structure damage leads to changes in etching rate. Furthermore, this method is also applicable to other ions, demonstrating its universality.
[0047] It should also be noted that the ion implantation dose can be controlled at 1E15 ions / cm². 2 Up to 1E17 ions / cm 2 Within this range, preferably, it can be 1E16 ions / cm 2 This dosage range ensures sufficient structural damage to cause a significant change in the etching rate, while avoiding excessive sputtering or stripping of the dielectric layer due to excessive dosage. In conjunction with the foregoing description, the etching process is preferably HF vapor phase etching. The flow rate ratio of EtOH gas to HF gas is preferably controlled between 0.5:1 and 2:1, which effectively regulates etching selectivity and reaction rate. Furthermore, the chamber pressure for vapor phase etching is preferably controlled within the range of 100 mTorr to 500 mTorr. This pressure range effectively balances etching rate and etching uniformity, avoiding excessively low pressure leading to a slow rate, or excessively high pressure causing unnecessary lateral etching.
[0048] In practice, a sample treated with ion implantation is taken and subjected to two independent etching experiments using the same HF vapor phase etching process formulation as in step S103 (including the aforementioned preferred gas flow ratio and chamber pressure). First, etching is performed for the first etching duration, and immediately after etching, the remaining thickness of the dielectric layer is measured using an ellipsometry. Second, etching is performed on another identical implanted sample for the second etching duration, and the remaining thickness is measured using an ellipsometry after etching. By comparing these two remaining thicknesses with the initial thickness of the dielectric, the thickness change value under the first etching duration (initial thickness of the dielectric - remaining thickness of the dielectric layer under the first etching duration) and the thickness change value under the second etching duration (initial thickness of the dielectric - remaining thickness of the dielectric layer under the second etching duration) can be accurately determined.
[0049] S105. Based on the thickness change of the dielectric layer at each etching duration, determine whether the etching process corresponding to each etching duration corresponds to two different types of etching; the two different types of etching are etching only the injection layer and etching both the injection layer and the dielectric layer simultaneously.
[0050] It should be noted that the purpose of this step is to verify whether the previously selected etching duration successfully captures the two material regions with different etching rates: the implanted layer and the unimplanted dielectric layer, thereby determining the validity of subsequent calculations. This verification process is based on a reasonable physical assumption and proof by contradiction. Specifically, based on the thickness change of the dielectric layer at various etching durations, it determines whether the etching process corresponding to each etching duration corresponds to two different types of etching, including:
[0051] (1) Assuming that only the injection layer is etched during the second etching duration, the assumed etching rate of the injection layer is determined based on the thickness change of the dielectric layer during the second etching duration and the second etching duration.
[0052] First, an initial assumption is made that during the longer second etching duration, the total thickness change of the medium is determined solely by the implanted layer, which has a faster etching rate. Based on this assumption, an assumed etching rate for the implanted layer can be calculated from the total thickness change during the second etching duration (i.e., assumed etching rate = thickness change during the second etching duration / second etching duration). This rate is an estimated value under the given assumptions.
[0053] (2) Assuming that the injection layer and the dielectric layer are etched simultaneously during the first etching duration, calculate the first assumed duration for etching the injection layer during the first etching duration based on the thickness change of the dielectric layer during the first etching duration, the first etching rate and the assumed etching rate.
[0054] Subsequently, using the assumed etching rate described above, we verify what happens during the relatively short first etching duration, assuming that the etching process involves both the implanted layer and the underlying original dielectric layer within the first etching duration. Based on this, we can deduce the actual time spent etching the implanted layer within the first etching duration—that is, the first assumed duration—by establishing and solving a system of equations, using the thickness change during the first etching duration, the precisely measured first etching rate, and the assumed etching rate obtained in the previous step.
[0055] Specifically, calculating the first assumed etching duration of the implanted layer at the first etching duration based on the thickness change of the dielectric layer at the first etching duration, the first etching rate, and the assumed etching rate includes:
[0056] (i) Based on the first etching duration, construct a first correlation between the first assumed duration of etching the injection layer under the first etching duration and the second assumed duration of etching the medium layer under the first etching duration.
[0057] Specifically, the first correlation is: First assumed duration + Second assumed duration = First etching duration. The second assumed duration is the time required to etch the original dielectric layer.
[0058] (ii) Based on the first etching rate, the first assumed duration, the second etching rate, the second assumed duration, and the thickness change of the dielectric layer under the first etching duration, establish a second correlation relationship corresponding to the thickness change.
[0059] Specifically, the second correlation is: (assumed etching rate × first assumed duration) + (first etching rate × second assumed duration) = thickness change under the first etching duration.
[0060] (iii) Combine the first correlation relationship and the second correlation relationship to form a system of equations, and solve the system of equations to obtain the first assumed duration and the second assumed duration.
[0061] For details on the solution process, please refer to the relevant technical descriptions; they will not be repeated here.
[0062] (3) When the first assumed duration is greater than or equal to the second etching duration, the etching process corresponding to each etching duration corresponds to two different types of etching.
[0063] Specifically, if the first etching duration is greater than or equal to the second etching duration, then to interpret the data for the first etching duration, it is necessary to assume that the etching time for the implantation layer is longer than the entire second etching duration. This contradicts the initial assumption (that only the implantation layer was etched during the second etching duration) which is invalid. This means that within the second etching duration, the etching has already penetrated the implantation layer and entered the original dielectric layer, thus determining that the etching process corresponds to two different types of etching.
[0064] (4) When the first assumed duration is less than the second etching duration, it is determined that the etching process corresponding to each etching duration does not correspond to two different types of etching.
[0065] If the first assumed duration is less than the second etching duration, it indicates that the initial assumption may be valid, meaning that the two selected etching durations failed to effectively distinguish between the two etching mechanisms. In this case, it is necessary to return to step S102 and readjust the etching duration parameters.
[0066] S106. If yes, determine the thickness of the injection layer based on the first etching rate and the thickness change of the dielectric layer under each etching duration; otherwise, execute the step of determining the first etching duration and the second etching duration based on the first duration again.
[0067] It should be noted that the thickness calculation step is only executed when the judgment result of S105 is yes (i.e., confirming that the etching process successfully corresponds to two different types of etching). At this time, the successive etching processes of the injected layer and the uninjected dielectric layer are accurately reflected, and the thickness calculation based on this is reliable.
[0068] Specifically, determining the thickness of the implanted layer based on the first etching rate and the thickness variation of the dielectric layer at various etching durations includes:
[0069] (1) Determine the assumed etching rate of the injection layer based on the thickness change of the dielectric layer under the second etching duration and the second etching duration.
[0070] Again, based on the total thickness change of the dielectric layer during the second etching duration and the second etching duration, the etching rate of the implanted layer is calculated. Although the calculation formula here is the same as step (1) in S105, its physical meaning is different. In S105, this is an assumed value used for verification, while here, since the verification has passed, this rate is confirmed as an effective implanted layer etching rate that can be used for the final calculation.
[0071] (2) Calculate the thickness of the injection layer based on the thickness change of the dielectric layer during the first etching time, the first etching rate, and the assumed etching rate.
[0072] Specifically, all parameters obtained throughout the measurement and verification process are substituted into a mathematical model to calculate the implanted layer thickness. This mathematical model describes that the total etching thickness during the second etching duration consists of two parts: the thickness H of the implanted layer etched at rate S2, and the thickness L of the underlying original dielectric layer etched at rate S1. The following set of equations is thus established:
[0073] Total thickness variation relationship: H + L = ΔD;
[0074] Total time relationship: t1 + t2 = T2;
[0075] Layered etching relationship: H=S2×t1 and L=S1×t2.
[0076] Combining the above relationships, the thickness H of the injected layer can be finally solved as:
[0077] H=S2×[(ΔD-S1×T2) / (S2-S1)].
[0078] Wherein, H represents the thickness of the implanted layer; S2 represents the etching rate of the implanted layer; t1 represents the actual time for etching the implanted layer within the second etching duration; L represents the thickness of the unimplanted dielectric layer etched within the second etching duration; S1 represents the first etching rate; t2 represents the actual time for etching the unimplanted dielectric layer within the second etching duration; ΔD represents the total thickness change of the dielectric layer treated by the ion implantation process within the second etching duration; and T2 represents the second etching duration.
[0079] Through the above calculations, we finally obtained the junction depth H of ion implantation. This method eliminates the dependence on expensive equipment such as TOF-SIMS and realizes low-cost and high-efficiency junction depth measurement.
[0080] Furthermore, if the judgment result of S105 is negative, the process will jump back to S102. This indicates that the initially selected combination of etching durations is insufficient to clearly distinguish between the two etching mechanisms (e.g., both times are too short to penetrate the injection layer). Based on the data feedback from the initial experiment, the system will determine a new, more reasonable set of first and second etching durations (e.g., appropriately extending the etching time) and re-execute the subsequent processes. This design ensures its practicality and success rate under various process conditions.
[0081] The method provided in this embodiment utilizes the effect of material etching rate changes caused by ion implantation, combined with a complete self-verifying measurement process, to achieve low-cost, high-efficiency, and high-reliability measurement of implanted junction depth. Specifically, by determining a first etching duration to set a safety boundary for the entire etching process, substrate damage is effectively prevented, ensuring the feasibility and safety of the measurement. By selecting a first etching duration and a second etching duration and performing etching separately, thickness data that clearly reflects the two different states of etched implanted layer and etched non-implanted layer is successfully obtained, laying the foundation for model calculation. Furthermore, through verification logic including hypothesis, proof by contradiction, and iterative adjustment steps, it is ensured that the selected process parameters can effectively distinguish between the two etching mechanisms, thereby significantly improving the accuracy of the measurement results and the adaptability of the method under different process conditions. In addition, this method only requires conventional ellipsometry and etching equipment to complete accurate measurements, fundamentally eliminating the dependence on expensive dedicated analytical instruments such as TOF-SIMS.
[0082] Example 2
[0083] Corresponding to the aforementioned embodiment of the ion implantation depth measurement method, this application also provides an embodiment of an ion implantation depth measurement device.
[0084] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the ion implantation depth measurement device provided in this application. Please refer to... Figure 2 The apparatus provided in this embodiment includes a determining module 210, an etching module 220, and a processing module 230;
[0085] The determining module 210 is used to determine a first duration based on the pre-measured thickness of the dielectric layer, the currently selected etching process, and the pre-determined relationship between the etching process and the etching rate of the dielectric layer.
[0086] The determining module 210 is further configured to determine a first etching duration and a second etching duration based on the first duration; the first etching duration is less than the second etching duration; and both the first etching duration and the second etching duration are less than the first duration.
[0087] The etching module 220 is used to etch the dielectric layer that has not been treated by the ion implantation process for the second etching time according to the currently selected etching process, and to determine the first etching rate of the dielectric layer based on the first thickness change value of the dielectric layer during the etching process and the second etching time.
[0088] The etching module 220 is further configured to perform etching of the dielectric layer treated by the ion implantation process for the first etching time and the second etching time respectively according to the currently selected etching process, and determine the thickness change of the dielectric layer under each etching time.
[0089] The processing module 230 is used to determine whether the etching process corresponding to each etching duration corresponds to two different types of etching based on the thickness change of the dielectric layer at each etching duration; the two different types of etching are etching only the injection layer and etching both the injection layer and the dielectric layer simultaneously.
[0090] If so, the thickness of the injection layer is determined based on the first etching rate and the thickness change of the dielectric layer at each etching duration; otherwise, the step of determining the first etching duration and the second etching duration based on the first duration is executed again.
[0091] The apparatus of this embodiment can be used to perform... Figure 1 The steps of the method embodiment shown are similar in principle and process, and will not be repeated here.
[0092] The specific implementation process of the functions and roles of each unit in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.
[0093] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this application according to actual needs. Those skilled in the art can understand and implement this without creative effort.
[0094] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A method for measuring ion implantation depth, characterized in that, The method is used to measure the thickness of the implanted layer formed after the dielectric layer is subjected to an ion implantation process. The dielectric layer is formed on the substrate; The method includes: The first duration is determined based on the pre-measured thickness of the dielectric layer, the currently selected etching process, and the pre-determined relationship between the etching process and the etching rate of the dielectric layer. The first etching duration and the second etching duration are determined based on the first duration; the first etching duration is less than the second etching duration; both the first etching duration and the second etching duration are less than the first duration; The dielectric layer that has not been treated by ion implantation is etched according to the currently selected etching process for the second etching duration, and the first etching rate of the dielectric layer is determined based on the first thickness change value of the dielectric layer during the etching process and the second etching duration. According to the currently selected etching process, the dielectric layer treated by the ion implantation process is etched for the first etching time and the second etching time, respectively, and the thickness change of the dielectric layer at each etching time is determined. Based on the thickness variation of the dielectric layer at various etching durations, it is determined whether the etching process corresponding to each etching duration corresponds to two different types of etching; the two different types of etching are etching only the injection layer and etching both the injection layer and the dielectric layer simultaneously. If so, the thickness of the injection layer is determined based on the first etching rate and the thickness change of the dielectric layer at each etching duration; otherwise, the step of determining the first etching duration and the second etching duration based on the first duration is executed again.
2. The method according to claim 1, characterized in that, Based on the thickness variation of the dielectric layer at various etching durations, determine whether the etching process corresponding to each etching duration corresponds to two different types of etching, including: Assuming that only the implantation layer is etched during the second etching duration, the assumed etching rate of the implantation layer is determined based on the thickness change of the dielectric layer during the second etching duration and the second etching duration. Assuming that the implantation layer and the dielectric layer are etched simultaneously during the first etching duration, the first assumed etching duration for etching the implantation layer during the first etching duration is calculated based on the thickness change of the dielectric layer during the first etching duration, the first etching rate, and the assumed etching rate. When the first assumed duration is greater than or equal to the second etching duration, it is determined that the etching process corresponding to each etching duration corresponds to two different types of etching. When the first assumed duration is less than the second etching duration, it is determined that the etching process corresponding to each etching duration does not correspond to two different types of etching.
3. The method according to claim 2, characterized in that, The step of calculating the first assumed etching duration of the implanted layer at the first etching duration based on the thickness change of the dielectric layer at the first etching duration, the first etching rate, and the assumed etching rate includes: Based on the first etching duration, a first correlation relationship is established between the first assumed duration of etching the injection layer under the first etching duration and the second assumed duration of etching the dielectric layer under the first etching duration; Based on the first etching rate, the first assumed duration, the second etching rate, the second assumed duration, and the thickness change of the dielectric layer under the first etching duration, a second correlation relationship corresponding to the thickness change is established; The first and second relationships are combined to form a system of equations, and the system of equations is solved to obtain the first assumed duration and the second assumed duration.
4. The method according to claim 1, characterized in that, The step of determining the thickness of the implanted layer based on the first etching rate and the thickness variation of the dielectric layer at various etching durations includes: The assumed etching rate of the injection layer is determined based on the thickness change of the dielectric layer during the second etching duration and the second etching duration. The thickness of the injection layer is calculated based on the thickness change of the dielectric layer during the first etching duration, the first etching rate, and the assumed etching rate.
5. The method according to claim 1, characterized in that, The ion types used in the ion implantation process include at least one of the following: argon ions, boron ions, phosphorus ions, arsenic ions, oxygen ions, nitrogen ions, magnesium ions, and aluminum ions.
6. The method according to claim 1, characterized in that, The substrate is a silicon substrate, and the dielectric layer is silicon dioxide; in the currently selected etching process, the flow ratio of EtOH gas to HF gas is controlled between 0.5:1 and 2:
1.
7. The method according to claim 1, characterized in that, The ion implantation process is performed with an implantation dose range of 1E15 ions / cm². 2 Up to 1E17 ions / cm 2 .
8. The method according to claim 1, characterized in that, The thickness variation of the dielectric layer at various etching durations was determined based on ellipsometer measurements.
9. The method according to claim 1, characterized in that, The etching process is vapor phase etching, and the chamber pressure of the vapor phase etching is controlled within the range of 100 mTorr to 500 mTorr.
10. An ion implantation depth measurement device, characterized in that, The device includes a determination module, an etching module, and a processing module; The determining module is used to determine the first duration based on the pre-measured thickness of the dielectric layer, the currently selected etching process, and the pre-determined relationship between the etching process and the etching rate of the dielectric layer. The determining module is further configured to determine a first etching duration and a second etching duration based on the first duration; the first etching duration is less than the second etching duration; and both the first etching duration and the second etching duration are less than the first duration. The etching module is used to etch the dielectric layer that has not been treated by the ion implantation process for the second etching time according to the currently selected etching process, and to determine the first etching rate of the dielectric layer based on the first thickness change value of the dielectric layer during the etching process and the second etching time. The etching module is further configured to etch the dielectric layer treated by the ion implantation process for the first etching time and the second etching time respectively according to the currently selected etching process, and determine the thickness change of the dielectric layer at each etching time; The processing module is used to determine whether the etching process corresponding to each etching duration corresponds to two different types of etching based on the thickness change of the dielectric layer at each etching duration; the two different types of etching are etching only the injection layer and etching both the injection layer and the dielectric layer simultaneously. If so, the thickness of the injection layer is determined based on the first etching rate and the thickness change of the dielectric layer at each etching duration; otherwise, the step of determining the first etching duration and the second etching duration based on the first duration is executed again.