Granularity measurement method of carbon-based photoetching material
By depositing a dielectric layer on the substrate and etching to remove the carbon-based lithography material, combined with reference particle distribution information, the accuracy of the particle size measurement of carbon-based lithography material is solved, and a more accurate particle size measurement is achieved.
Patent Information
- Application Number
- CN202311847389.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-01
AI Technical Summary
When measuring the particle size of carbon-based lithography materials, the prior art is affected by factors such as the surface roughness, refractive index and coating thickness of carbon-based lithography materials, resulting in inaccurate test results and require continuous spectral correction, making it difficult to accurately reflect the particle size.
A dielectric layer different from the type of carbon-based lithography material is deposited on the substrate, coated with the carbon-based lithography material to be measured and etched and removed. The particle distribution information on the surface of the dielectric layer is measured, and the particle size of the particle added in the target particle distribution information is determined using the reference particle distribution information as a reference.
By acting as an etching barrier layer, the influence of factors such as the thickness and surface roughness of carbon-based lithography material is avoided, the accuracy and reliability of the measurement results are ensured, and more accurate particle size data is provided.
Smart Images
Figure CN120232779A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of integrated circuit manufacturing, and particularly to a method for measuring the particle size of a carbon-based lithography material. Background Art
[0002] The particle size of a lithography material is a key indicator for measuring the quality of the lithography material. A low particle size can ensure that no defects are generated in the chip during the manufacturing process due to the particles in the lithography material, thereby improving the yield and electrical performance of the chip. Therefore, how to accurately measure the number of particles in the lithography material is an important part of material evaluation and verification.
[0003] Currently, when measuring the particle size of a carbon-based lithography material, the commonly used method is as follows: First, use an SP series particle testing machine to measure the number of particles on the substrate, and this number of particles is used as the previous value; then coat the carbon-based lithography material on the substrate, and use the same testing machine to measure the number of particles again, and this number of particles is used as the subsequent value; the difference between the previous value of the number of particles and the subsequent value of the number of particles is the number of particles in the carbon-based lithography material. This testing method is not accurate because the principle of the SP series particle testing machine is to use obliquely incident elliptically polarized light to strike the surface of the substrate to be tested, causing reflection and diffuse scattering. The collection cylinder of the machine then collects the reflected and diffusely scattered light signals, and the surface condition of the substrate is obtained by analyzing the signal intensity and phase change of these lights. When a carbon-based lithography material 2 is coated on the surface of the substrate 1, part of the incident light is reflected and diffusely reflected on the surface of the carbon-based lithography material 2, and another part of the light is refracted into the carbon-based lithography material 2, and then reflected at the contact surface between the carbon-based lithography material 2 and the substrate 1, and then penetrates through the carbon-based lithography material 2 and is reflected out. The carbon-based lithography material 2 contains particles 3, as Figure 1 shown. Therefore, factors such as the surface roughness of the carbon-based lithography material, the refractive index of the carbon-based lithography material, and the thickness of the silicon-based lithography coating will all affect the accuracy of the test results, and continuous spectral calibration needs to be carried out for each material and each thickness. Otherwise, it is very easy to cause false detection of particles. Therefore, the method of spin-coating the carbon-based lithography material on the substrate and then measuring the particle size of the carbon-based lithography material cannot accurately reflect the particle size of the carbon-based lithography material.
[0004] Therefore, how to solve the above technical problems should be the focus of attention of those skilled in the art. Summary of the Invention
[0005] The purpose of the present application is to provide a method for measuring the particle size of a carbon-based lithography material to improve the accuracy of measuring the particle size of the carbon-based lithography material.
[0006] To solve the above technical problems, the present application provides a method for measuring the particle size of a carbon-based lithography material, including:
[0007] Obtain a substrate with a dielectric layer deposited on its upper surface; the dielectric layer is of a different type from the carbon-based lithography material to be tested;
[0008] Coat the carbon-based photolithography material to be tested on the upper surface of the dielectric layer;
[0009] Etch and remove the carbon-based photolithography material to be tested;
[0010] Measure the target particle distribution information on the surface of the dielectric layer;
[0011] Taking the reference particle distribution information as a reference, determine that the particles increased in the target particle distribution information are the particle size of the carbon-based photolithography material to be tested;
[0012] Wherein, the reference particle distribution information is the particle distribution information before the carbon-based photolithography material to be tested is coated on the upper surface of the dielectric layer, and the reference particle distribution information and the target particle distribution information are measured by the same test equipment.
[0013] Optionally, before obtaining the substrate with the dielectric layer deposited on the upper surface, it further includes:
[0014] Deposit the dielectric layer on the upper surface of the substrate.
[0015] Optionally, depositing the dielectric layer on the upper surface of the substrate includes:
[0016] Deposit a silicon dioxide layer on the upper surface of the substrate.
[0017] Optionally, the target particle distribution information includes a target particle distribution image, and the reference particle distribution information includes a reference particle distribution image. Taking the reference particle distribution information as a reference, determining that the particles increased in the target particle distribution information are the particle size of the carbon-based photolithography material to be tested includes:
[0018] Compare the reference particle distribution image and the target particle distribution image, and determine that the number of particles increased in the target particle distribution image is the particle size of the carbon-based photolithography material to be tested.
[0019] Optionally, the target particle distribution information includes a target particle distribution quantity, and the reference particle distribution information includes a reference particle distribution quantity. Taking the reference particle distribution information as a reference, determining that the particles increased in the target particle distribution information are the particle size of the carbon-based photolithography material to be tested includes:
[0020] Determine the difference between the target particle distribution quantity and the reference particle distribution quantity as the particle size of the carbon-based photolithography material to be tested.
[0021] Optionally, the thickness range of the dielectric layer is 100 angstroms to 500 angstroms.
[0022] Optionally, coating the carbon-based photolithography material to be tested on the upper surface of the dielectric layer includes:
[0023] Coat a photoresist on the upper surface of the dielectric layer.
[0024] Optionally, coating the carbon-based photolithography material to be measured on the upper surface of the dielectric layer includes:
[0025] Coat a bottom anti-reflection coating on the upper surface of the dielectric layer.
[0026] Optionally, coating the carbon-based photolithography material to be measured on the upper surface of the dielectric layer includes:
[0027] Spin-coat carbon on the upper surface of the dielectric layer.
[0028] Optionally, etching to remove the carbon-based photolithography material to be measured includes:
[0029] Use Cl2 and O2 plasma to etch and remove the carbon-based photolithography material to be measured.
[0030] A method for measuring the particle size of a carbon-based photolithography material provided in this application includes: obtaining a substrate with a dielectric layer deposited on its upper surface; the dielectric layer is of a different type from the carbon-based photolithography material to be measured; coating the carbon-based photolithography material to be measured on the upper surface of the dielectric layer; etching the carbon-based photolithography material to be measured; measuring the target particle distribution information on the surface of the dielectric layer; using the reference particle distribution information as a reference, determining the particles increased in the target particle distribution information as the particle size of the carbon-based photolithography material to be measured; wherein, the reference particle distribution information is the particle distribution information before the carbon-based photolithography material to be measured is coated on the upper surface of the dielectric layer, and the reference particle distribution information and the target particle distribution information are measured by the same testing device.
[0031] It can be seen that when measuring the particle size of the carbon-based photolithography material in this application, the carbon-based photolithography material is coated on the upper surface of the dielectric layer located on the substrate, and then the carbon-based photolithography material is etched off. The dielectric layer serves as an etching barrier layer and will not be etched. The impurity particles in the carbon-based photolithography material will fall on the upper surface of the dielectric layer, and the target particle distribution information on the upper surface of the dielectric layer at this time is measured. Then, the target particle distribution information is compared with the reference particle distribution information on the surface of the dielectric layer before coating the carbon-based photolithography material. The particles increased in the target particle distribution information are the particle size of the carbon-based photolithography material. This testing method is not affected by the thickness, surface roughness, etc. of the carbon-based photolithography material to be measured, and since the surface of the dielectric layer will not be etched, the surface of the dielectric layer remains flat after the carbon-based photolithography material is etched, which will not affect the measurement of the target particle distribution information. Therefore, the particle size of the carbon-based photolithography material measured in this application is more accurate. Description of the Drawings
[0032] To more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0033] Figure 1 It is a schematic diagram of the principle for measuring the particle size of carbon-based lithography materials by the SP series particle testing machine in the related art;
[0034] Figure 2 It is the flow of a method for measuring the particle size of a carbon-based lithography material provided by an embodiment of the present application Figure 1 ;
[0035] Figures 3 to 4 It is a schematic diagram of the particle distribution image during the measurement of the particle size of a carbon-based lithography material provided by an embodiment of the present application;
[0036] Figure 5 It is the flow of a method for measuring the particle size of a carbon-based lithography material provided by an embodiment of the present application Figure 2 ;
[0037] Figures 6 to 9 It is a process flow diagram for measuring the particle size of a carbon-based lithography material provided by an embodiment of the present application. Detailed implementation manners
[0038] In order to enable those skilled in the art to better understand the solution of the present application, the following will further elaborate on the present application in conjunction with the drawings and specific implementation manners. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.
[0039] As described in the background art section, currently when measuring the particle size of carbon-based lithography materials, the carbon-based lithography material is directly coated on the substrate, and the number of particles on the substrate before and after coating the carbon-based lithography material is measured by the SP series particle testing machine. The difference between the two particle numbers is the particle size of the carbon-based lithography material. However, due to the problems of the testing principle of the SP series particle testing machine, factors such as the surface roughness of the carbon-based lithography material, the refractive index of the carbon-based lithography material, and the thickness of the silicon-based lithography coating will affect the accuracy of the test results. It is necessary to continuously perform spectral calibration for each material and each thickness, otherwise it is very easy to cause false detection of particles.
[0040] In view of this, the present application provides a method for measuring the particle size of a carbon-based lithography material. Please refer to Figure 2, the method includes:
[0041] Step S101: Obtain a substrate with a dielectric layer deposited on its upper surface; the dielectric layer is of a different type from the carbon-based lithography material to be measured.
[0042] The substrate can be a bare silicon wafer or other types of substrates, which are not specifically limited in this embodiment.
[0043] The substrate with a dielectric layer deposited on its upper surface can be directly obtained as already prepared, or the dielectric layer can be fabricated on the substrate by itself.
[0044] As an implementable manner, before obtaining the substrate with a dielectric layer deposited on its upper surface, it may further include: depositing the dielectric layer on the upper surface of the substrate.
[0045] The thickness range of the dielectric layer can be 100 angstroms to 500 angstroms. For example, the thickness of the dielectric layer can be 100 angstroms, 200 angstroms, 300 angstroms, 400 angstroms, 500 angstroms, etc.
[0046] In this embodiment, the particle size of the carbon-based lithography material is measured. The carbon-based lithography material contains carbon, and the dielectric layer is of a different type from the carbon-based lithography material to be measured, that is, the material of the dielectric layer is a carbon-free material. For example, the material of the dielectric layer can be a silicon-containing material.
[0047] Step S102: Coat the carbon-based lithography material to be measured on the upper surface of the dielectric layer.
[0048] To improve the uniformity of the coating thickness of the carbon-based lithography material to be measured on the dielectric layer, as an implementable manner, the carbon-based lithography material to be measured can be coated on the upper surface of the dielectric layer by spin coating.
[0049] It should be noted that the type of the carbon-based lithography material to be measured is not limited in this embodiment.
[0050] As an implementable manner, when the carbon-based lithography material to be measured is a photoresist (abbreviated as PR), coating the carbon-based lithography material to be measured on the upper surface of the dielectric layer includes:
[0051] Coating a photoresist on the upper surface of the dielectric layer.
[0052] As another implementable manner, when the carbon-based lithography material to be measured is a bottom anti-reflection coating (abbreviated as BARC), coating the carbon-based lithography material to be measured on the upper surface of the dielectric layer includes:
[0053] Coating a bottom anti-reflection coating on the upper surface of the dielectric layer.
[0054] As another implementable manner, when the carbon-based lithography material to be measured is spin-on carbon (SOC), coating the carbon-based lithography material to be measured on the upper surface of the dielectric layer includes:
[0055] Coating spin-on carbon on the upper surface of the dielectric layer.
[0056] Step S103: Etch and remove the carbon-based lithography material to be measured.
[0057] In this step, the etching stops at the interface between the carbon-based lithography material to be measured and the dielectric layer.
[0058] The etching completely removes the carbon-based lithography material to be measured. The impurity particles in the carbon-based lithography material to be measured that are not reacted by the etching gas fall on the surface of the dielectric layer, and the dielectric layer is not etched. Therefore, a gas with a high etching selectivity for the carbon-based lithography material to be measured can be used for etching, and the etching stops at the upper surface of the dielectric layer.
[0059] As an implementable manner, etching and removing the carbon-based lithography material to be measured includes:
[0060] Using Cl2 and O2 plasma to etch and remove the carbon-based lithography material to be measured.
[0061] Step S104: Measure the target particle distribution information on the surface of the dielectric layer.
[0062] The target particle distribution information is obtained by measuring the upper surface of the dielectric layer after etching the carbon-based lithography material to be measured. The measurement can use an SP series particle testing machine in related technologies, such as an SP2 machine, an SP3 machine, or an SP5 machine, etc. When testing, the selected particle size range on the testing machine can be selected according to the actual situation. For example, a mode with a size of 120nm can be selected for measurement.
[0063] The target particle distribution information is an image obtained by measurement, and particles are distributed on the image. In addition, the target particle distribution information can also include the number of particles.
[0064] Step S105: Using the reference particle distribution information as a reference, determine that the particles increased in the target particle distribution information are the particle size of the carbon-based lithography material to be measured;
[0065] Wherein, the reference particle distribution information is the particle distribution information before coating the carbon-based lithography material to be measured on the upper surface of the dielectric layer, and the reference particle distribution information and the target particle distribution information are measured by the same testing equipment.
[0066] The reference particle distribution information is measured using a test device before coating the carbon-based lithography material. The reference particle distribution information and the target particle distribution information are measured by the same test device, which can avoid the error influence of the test device on the test results and ensure the accuracy of the test results.
[0067] As an implementable manner, the target particle distribution information includes a target particle distribution image, and the reference particle distribution information includes a reference particle distribution image. Taking the reference particle distribution information as a reference, determining the particles added in the target particle distribution information as the particle size of the carbon-based lithography material to be tested includes:
[0068] Comparing the reference particle distribution image and the target particle distribution image, and determining the number of particles added in the target particle distribution image as the particle size of the carbon-based lithography material to be tested.
[0069] By comparing the target particle distribution image and the reference particle distribution image, it is determined that the particles added in the target particle distribution image are the particle size in the carbon-based lithography material to be tested.
[0070] As another implementable manner, the target particle distribution information is the target particle distribution quantity, and the reference particle distribution information is the reference particle distribution quantity. Taking the reference particle distribution information as a reference, determining the particles added in the target particle distribution information as the particle size of the carbon-based lithography material to be tested includes:
[0071] Determining the difference between the target particle distribution quantity and the reference particle distribution quantity as the particle size of the carbon-based lithography material to be tested.
[0072] When determining the particle size of the carbon-based lithography material to be tested, it can be determined either by image comparison or by numerical subtraction, both of which are within the protection scope of this application.
[0073] Please refer to Figures 3 to 4 , Figure 3 is an image of the particle size distribution information on the upper surface of the dielectric layer after depositing the dielectric layer on the substrate, Figure 4 is an image of the particle size distribution information on the upper surface of the dielectric layer after etching the carbon-based lithography material to be tested, Figure 3 and Figure 4 The different shapes of the particles in represent different size sizes. It can be seen that after removing the carbon-based lithography material to be tested by the etching method, the particle distributions are the same. Therefore, the test scheme in this application is true and effective, and this method can reflect the real number of particles in the carbon-based lithography material to be tested. By comparing Figure 4 and Figure 3 it can be known that the particle distributions are the same after etching the carbon-based lithography material to be tested, and one particle is added. Figure 4 The particle pointed by the arrow in is the particle size of the carbon-based lithography material to be tested, which is 1 particle.
[0074] Among them Figure 3 the number of particles measured in Figure 3 is 17, Figure 4 the number of particles measured in Figure 4 is 18. If directly using Figure 4 the number of particles in Figure 4 minus Figure 3 the number of particles in Figure 3 can also obtain the required particle size. Therefore, in this application, the particle size distribution information can be either an image or a numerical value.
[0075] In this embodiment, when measuring the particle size of the carbon-based lithography material, the carbon-based lithography material is coated on the upper surface of the dielectric layer located on the substrate, and then the carbon-based lithography material is etched away. The dielectric layer serves as an etch stop layer and will not be etched. The impurity particles in the carbon-based lithography material will then fall on the upper surface of the dielectric layer, and the target particle distribution information on the upper surface of the dielectric layer at this time is measured. Then, the target particle distribution information is compared with the reference particle distribution information on the surface of the dielectric layer before coating the carbon-based lithography material. The increased particles in the target particle distribution information are the particle size of the carbon-based lithography material. Since the surface of the dielectric layer will not be etched, the surface of the dielectric layer remains flat after etching the carbon-based lithography material and will not affect the measurement of the target particle distribution information. Therefore, the particle size of the carbon-based lithography material measured in this application is more accurate.
[0076] Please refer to Figure 5 , on the basis of the above embodiment, in an embodiment of this application, the method for measuring the particle size of the carbon-based lithography material includes:
[0077] Step S201: Deposit a silicon dioxide layer on the upper surface of the substrate and measure the particle distribution information on the surface of the silicon dioxide layer as the reference particle distribution information.
[0078] It should be noted that in this embodiment, the deposition method of the silicon dioxide layer is not limited and can be selected arbitrarily.
[0079] As an implementable manner, depositing a silicon dioxide layer on the upper surface of the substrate includes:
[0080] Adopt any one of plasma enhanced chemical vapor deposition (PECVD for short), low pressure chemical vapor deposition (LPCVD for short), and atmospheric pressure chemical vapor deposition (APCVD for short) technologies to deposit a silicon dioxide layer on the upper surface of the substrate.
[0081] The thickness range of the silicon dioxide layer can be from 100 angstroms to 500 angstroms. For example, the thickness of the silicon dioxide layer can be 100 angstroms, 200 angstroms, 300 angstroms, 400 angstroms, 500 angstroms, etc.
[0082] As Figure 6 and Figure 7 shown, the silicon dioxide layer 4 is deposited on the upper surface of the substrate 1.
[0083] Step S202: Coat the carbon-based lithography material to be measured on the upper surface of the silicon dioxide layer.
[0084] As Figure 8 shown, the carbon-based lithography material 5 to be measured is spin-coated on the upper surface of the silicon dioxide layer 4.
[0085] Step S203: Use Cl2 and O2 plasma to etch the carbon-based lithography material to be measured, and etch until the interface between the carbon-based lithography material to be measured and the silicon dioxide layer.
[0086] As Figure 9 shown, after etching, the carbon-based lithography material 5 to be measured is etched away, and the impurity particles 3 in the carbon-based lithography material to be measured fall on the upper surface of the silicon dioxide layer 4.
[0087] Step S204: After etching the carbon-based lithography material to be measured, measure the target particle distribution information on the surface of the silicon dioxide layer.
[0088] Step S205: Using the reference particle distribution information as a reference, determine that the increased particles in the target particle distribution information are the particle size of the carbon-based lithography material to be measured;
[0089] Wherein, the reference particle distribution information and the target particle distribution information are measured by the same testing device.
[0090] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.
[0091] The above has introduced in detail the method for measuring the particle size of the carbon-based lithography material provided by the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present application, several improvements and modifications can still be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.
Claims
1. A method for measuring the particle size of a carbon-based lithography material, characterized in that, Including: Obtaining a substrate with a dielectric layer deposited on its upper surface; the dielectric layer is of a different type from the carbon-based photolithography material to be measured; Coating the carbon-based photolithography material to be measured on the upper surface of the dielectric layer; Etching and removing the carbon-based photolithography material to be measured; Measuring the target particle distribution information on the surface of the dielectric layer; Taking the reference particle distribution information as a reference, determining that the increased particles in the target particle distribution information are the particle size of the carbon-based photolithography material to be measured; Wherein, the reference particle distribution information is the particle distribution information before the carbon-based photolithography material to be measured is coated on the upper surface of the dielectric layer, and the reference particle distribution information and the target particle distribution information are measured by the same testing equipment.
2. The method for measuring the particle size of the carbon-based lithography material according to claim 1, characterized in that Before obtaining the substrate with the dielectric layer deposited on its upper surface, it further includes: Depositing the dielectric layer on the upper surface of the substrate.
3. The method for measuring the particle size of the carbon-based lithography material according to claim 2, wherein Depositing the dielectric layer on the upper surface of the substrate includes: Depositing a silicon dioxide layer on the upper surface of the substrate.
4. The method for measuring the particle size of the carbon-based lithography material according to claim 1, wherein, The target particle distribution information includes a target particle distribution image, and the reference particle distribution information includes a reference particle distribution image. Taking the reference particle distribution information as a reference, determining that the increased particles in the target particle distribution information are the particle size of the carbon-based photolithography material to be measured includes: Comparing the reference particle distribution image and the target particle distribution image, and determining that the number of increased particles in the target particle distribution image is the particle size of the carbon-based photolithography material to be measured.
5. The method for measuring the particle size of the carbon-based lithography material according to claim 1, wherein, The target particle distribution information includes a target particle distribution quantity, and the reference particle distribution information includes a reference particle distribution quantity. Taking the reference particle distribution information as a reference, determining that the increased particles in the target particle distribution information are the particle size of the carbon-based photolithography material to be measured includes: Determining the difference between the target particle distribution quantity and the reference particle distribution quantity as the particle size of the carbon-based photolithography material to be measured.
6. The method for measuring the particle size of the carbon-based lithography material according to claim 2, characterized in that, The thickness range of the dielectric layer is 100 angstroms to 500 angstroms.
7. The method for measuring the particle size of the carbon-based lithography material according to claim 1, wherein Coating the carbon-based photolithography material to be measured on the upper surface of the dielectric layer includes: Coating a photoresist on the upper surface of the dielectric layer.
8. The method for measuring the particle size of the carbon-based lithography material according to claim 1, characterized in that Coating the carbon-based photolithography material to be measured on the upper surface of the dielectric layer includes: Coating a bottom anti-reflection coating on the upper surface of the dielectric layer.
9. The method for measuring the particle size of the carbon-based lithography material according to claim 1, characterized in that, Coating the carbon-based photolithography material to be measured on the upper surface of the dielectric layer includes: Coating spin-on carbon on the upper surface of the dielectric layer.
10. The method for measuring the particle size of the carbon-based lithography material according to any one of claims 1 to 9, characterized in that, Etching and removing the carbon-based photolithography material to be measured includes: Using Cl2 and O2 plasma to etch and remove the carbon-based photolithography material to be measured.