Lens defect detection method, device, and semiconductor structure fabrication method

Abstract

This application relates to a lens defect detection method, apparatus, and semiconductor structure fabrication method. The lens defect detection method of this application includes: providing a wafer; the wafer including multiple exposure areas; exposing each of the exposure areas, wherein at least two different exposure energies are used during the multiple exposures; after the multiple exposures, determining whether the lens has a defect based on whether spots appear in each of the exposure areas; if spots appear in the exposure areas, then the lens is determined to have a defect. The lens defect detection method provided by this application, by exposing the same wafer with different exposure energies, can detect less obvious defects on the lens, exhibiting high sensitivity; moreover, the detection process is simple and easy to implement.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a method, apparatus, and method for preparing a semiconductor structure for detecting lens defects. Background Technology

[0002] The lithography machine is the most crucial piece of equipment in the entire chip industry chain, used to transfer patterns from a photomask to the surface of a wafer. During the exposure process, the light source in the lithography machine provides a beam of light and transmits it through the photomask on which the circuit pattern is drawn. Then, the lens in the lithography machine compensates for various optical errors in the transmitted beam, mapping the circuit pattern on the photomask onto the wafer surface.

[0003] The lens is one of the most crucial components of a lithography machine; its job is to direct light onto the wafer. Because the light must be uniform and have high resolution, the requirements for the lens are extremely high.

[0004] Therefore, how to detect defects in the lens of a lithography machine is an urgent problem that needs to be solved. Summary of the Invention

[0005] Based on this, this application provides a lens defect detection method, device, and semiconductor structure fabrication method, which can detect whether there are defects in the lens of a lithography machine, thereby improving the reliability of the prepared semiconductor structure and the production yield.

[0006] To achieve the above objectives, this application provides a lens defect detection method according to some embodiments, characterized in that it is used to detect whether a lens of a lithography machine has defects; the detection method includes:

[0007] Provide wafers;

[0008] The wafer is subjected to multiple exposures in different regions, and at least two different exposure energies are used in the multiple exposures.

[0009] After the multiple exposures, the presence of spots on the wafer is used to determine whether the lens has defects.

[0010] In one embodiment, the wafer includes multiple exposure areas arranged in an array; the multiple exposures include: exposing the exposure areas one by one or column by column;

[0011] The lens defect detection method also includes:

[0012] If, after multiple exposures, the spot appears in at least two of the same exposed areas of the lens, then the lens is defective.

[0013] In one embodiment, the areas of each of the exposure regions are equal.

[0014] In one embodiment, a plurality of the exposure regions are arranged in rows along the first direction and in columns along the second direction, wherein the first direction and the second direction intersect; and the exposure energies corresponding to adjacent columns of exposure regions are different.

[0015] In one embodiment, the exposure energy corresponding to the same column of exposure areas is the same, and the exposure energy corresponding to multiple columns of exposure areas gradually increases along the first direction.

[0016] In one embodiment, the exposure energy corresponding to the multiple exposure areas gradually increases along the first direction from a preset initial exposure energy according to a preset step size.

[0017] In one embodiment, the preset initial exposure energy is 80 millijoules to 120 millijoules.

[0018] In one embodiment, the preset step size is 8 millijoules to 12 millijoules.

[0019] On the other hand, according to some embodiments, this application also provides a lens defect detection device, which is used to implement the lens defect detection method provided in any of the foregoing embodiments.

[0020] Furthermore, according to some embodiments, this application also provides a method for fabricating a semiconductor structure, including:

[0021] Provide lithography machines;

[0022] The lens of the lithography machine is inspected using the lens defect detection method provided in any of the foregoing embodiments;

[0023] Once the lithography machine determines that the lens has no defects, it is used to fabricate a semiconductor structure.

[0024] The lens defect detection method, apparatus, and semiconductor structure fabrication method provided in this application have at least the following beneficial effects:

[0025] The detection method provided in this application, by exposing the same wafer with different exposure energies, can detect less obvious defects on the lens, exhibiting high sensitivity; moreover, the detection process is simple and easy to implement. By detecting defects in the lens of the lithography machine, adjustments can be made in a timely manner when defects are detected, avoiding the production of flawed products and improving the reliability and production yield of the prepared semiconductor structure.

[0026] The detection apparatus provided in this application is used to implement the detection method as described in the foregoing embodiments. Therefore, by exposing the same wafer with different exposure energies, it is possible to detect less obvious defects on the lens, exhibiting high sensitivity. Moreover, the detection process is simple and easy to implement. By detecting defects in the lens of the lithography machine, adjustments can be made in a timely manner when defects are detected, avoiding the production of defective products and improving the reliability and production yield of the prepared semiconductor structure.

[0027] The semiconductor structure fabrication method provided in this application uses the detection method provided in the foregoing embodiments to detect the lens of the lithography machine. When a defect is detected in the lens of the current lithography machine, it can be adjusted in time to avoid producing defective products. This is beneficial to improving the reliability and production yield of the prepared semiconductor structure. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A schematic flowchart of a detection method provided in one possible embodiment of this application;

[0030] Figure 2 A schematic diagram of the wafer structure provided in step S100 of the detection method provided in one possible embodiment of this application;

[0031] Figure 3 A schematic diagram of the structure in step S300 of the detection method provided in one possible embodiment of this application, showing the appearance of spots in the exposed area;

[0032] Figure 4 This is a schematic flowchart illustrating a method for fabricating a semiconductor structure according to one possible embodiment of this application.

[0033] Explanation of reference numerals in the attached figures:

[0034] 100. Wafer; 101. Exposure area; 102. Spot. Detailed Implementation

[0035] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. In the embodiments of this application, terms such as "in one possible embodiment of this application" or "in some possible embodiments" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "in one possible embodiment of this application" or "in some possible embodiments" in the embodiments of this application should not be construed as preferred or advantageous over other embodiments or designs. Specifically, the use of the terms "in one possible embodiment of this application" or "in some possible embodiments" is intended to present the relevant concepts in a specific manner.

[0037] When used herein, the singular forms of "a," "an," and "the" may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of this application, "at least two" and "more than" refer to two or more. The term "and / or" is used to describe the relationship between related objects, indicating that three relationships may exist; for example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0038] It should be noted that when the terms "compose" and / or "comprise" are used in this specification, the presence of the stated features, integers, steps, operations, elements, and / or components is confirmed, but the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups is not excluded. Furthermore, when used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0039] The embodiments of this application should not be limited to the specific shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing techniques. Therefore, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of the regions of the device, nor do they limit the scope of this application.

[0040] The lithography machine is the most crucial piece of equipment in the entire chip industry chain, used to transfer patterns from a photomask to the surface of a wafer. During exposure, a light source in the lithography machine provides a beam of light that passes through a photomask with the circuit pattern drawn on it. The lens in the lithography machine then compensates for various optical errors in the transmitted beam, mapping the circuit pattern from the photomask onto the wafer surface. The lens is one of the most critical components of the lithography machine; its job is to illuminate the wafer. Because the light must be uniform and have high resolution, the requirements for the lens are extremely high.

[0041] Therefore, how to detect defects in the lens of a lithography machine is an urgent problem that needs to be solved.

[0042] Currently, traditional methods for detecting defects in lithography machine lenses generally use fixed exposure energy. After exposure and development on a bare silicon wafer coated with photoresist, a pattern is formed. Then, the defect is determined by scanning with a wafer inspection device or by visual inspection by inspectors.

[0043] However, for fully exposed bare silicon wafers, the above detection methods can only detect relatively obvious defects on the lens, and therefore are only applicable to process inspection when lithography machines are used to produce traditional integrated circuits. If it is necessary to verify whether the lithography machine is suitable for manufacturing devices that are more sensitive to the lens, such as micro-electro-mechanical systems (MEMS) used for thermal infrared imaging, the sensitivity of traditional lithography machine lens defect detection methods is insufficient.

[0044] Based on this, this application provides a detection method according to some embodiments.

[0045] Please see Figure 1 In one possible embodiment of this application, the steps include:

[0046] S100: Provides wafers.

[0047] S200: Multiple exposures are performed on different areas of the wafer; at least two different exposure energies are used during the multiple exposures.

[0048] S300: After multiple exposures, the presence of spots on the wafer indicates whether the lens has defects.

[0049] Traditional inspection methods use fixed exposure energy. If this fixed energy fully exposes the entire wafer, subtle lens defects may go undetected or remain undetectable by visual inspection. The inspection method described above, however, uses different exposure energies to expose the same wafer, enabling the detection of less noticeable lens defects with high sensitivity. Furthermore, the inspection process is simple and easy to implement. By detecting defects in the lithography machine's lens, adjustments can be made promptly when defects are detected, preventing the production of flawed products and improving the reliability and yield of the resulting semiconductor structures.

[0050] To more clearly illustrate the detection method provided in the embodiments of this application, please refer to the following... Figures 2 to 3 Understand some possible embodiments of this application.

[0051] In step S100, please refer to Figure 2 100 wafers are provided.

[0052] In one possible embodiment of this application, wafer 100 can refer to a silicon wafer used in the manufacturing process of a semiconductor structure. Since its shape is generally circular, it is called a wafer. Various circuit element structures can be fabricated on wafer 100. In some possible embodiments, wafer 100 can also be a germanium (Ge) wafer, a gallium arsenide (GaAs) wafer, or a gallium nitride (GaN) wafer. Furthermore, the material of wafer 100 can also include silicon-on-insulator (SOI), silicon-on-insulator stacked (SSOI), silicon-on-insulator stacked (S-SiGeOI), silicon-on-insulator (SiGeOI), and / or germanium-on-insulator (GeOI), etc. The detection method provided in this application does not specifically limit the material of wafer 100; a suitable material for wafer 100 can be selected according to actual needs.

[0053] In step S200, please continue reading. Figure 2 The wafer is exposed multiple times in a 100-point area; at least two different exposure energies are used in the multiple exposure process.

[0054] As an example, such as Figure 2 As shown, wafer 100 may include multiple exposure regions 101 arranged in an array. Based on this, the step of performing multiple exposures on wafer 100 by region can be performed in the following manner, for example: exposing exposure regions 101 one by one or column by column.

[0055] Because at least two different exposure energies are used for exposure within the same wafer 100, at least two different states will occur in the exposure region 101 within the wafer 100. For example... Figure 2As shown, Figure 2 The labels indicate the fully exposed area 'a' and the completely unexposed area 'b'. Area 'a' includes two exposure areas 101 exposed at 150 millijoules (mJ) and 160 millijoules; area 'b' includes one exposure area 101 exposed at 100 millijoules.

[0056] It is understood that this application does not specifically limit the use of different exposure energies during the multiple exposures of wafer 100 in step S200; this can be adaptively set according to actual needs. In one possible embodiment of this application, such as Figure 2 As shown, seven different exposure energies can be used during the multiple exposures of wafer 100 in step S200. For example, during the multiple exposures of wafer 100 in step S200, seven different exposure energies of 100 millijoules, 110 millijoules, 120 millijoules, 130 millijoules, 140 millijoules, 150 millijoules, and 160 millijoules can be used to expose each exposure area 101.

[0057] The detection method provided in this application does not specifically limit the shape and size of the exposure area 101. As an example, each exposure area 101 may have the same area.

[0058] Please continue reading. Figure 2 In one possible embodiment of this application, multiple exposure areas 101 may be arranged in rows along a first direction and in columns along a second direction, with the first and second directions intersecting. Adjacent columns of exposure areas 101 correspond to different exposure energies.

[0059] like Figure 2 As shown, it can be Figure 2 The x-direction shown is the first direction in the embodiments of this application.

[0060] As an example, the exposure energy corresponding to the same column of exposure areas 101 can be the same, while the exposure energy corresponding to multiple columns of exposure areas 101 can gradually increase along the first direction.

[0061] The detection method provided in this application does not specifically limit the form of the exposure area 101. For example... Figure 2 As shown, wafer 100 may include multiple chips and scribe lines isolating each chip. The scribe lines are located between the chips and are adjacent to each chip; wherein the multiple chips are arranged in an array. In one possible embodiment of this application, the exposure area 101 may be an area including a row of chips.

[0062] In one possible embodiment of this application, during the multiple exposures in step S200, the exposure energy corresponding to the multiple exposure areas 101 can gradually increase along the first direction from a preset initial exposure energy according to a preset step size.

[0063] In the detection method provided in the above embodiments, multiple exposure areas are exposed sequentially. A preset initial exposure energy is used to expose one of the exposure areas for the first time. Then, starting from the preset initial exposure energy, the exposure energy of each field (one field refers to one exposure) is changed by a preset step size to expose the next exposure area. This allows for a visually detectable transition from completely unexposed to fully exposed areas. Figure 2 As shown. In other words, in the detection method provided in the above embodiments, each exposure is performed by increasing the exposure energy by a preset step size based on the exposure energy used in the previous exposure, thereby achieving a gradual effect.

[0064] It is understandable that a smaller preset step size creates a more gradual effect, thus increasing the sensitivity to defect detection in the lithography machine lens. Furthermore, the preset step size should be adaptively set based on the number of chips on the wafer 100 during the actual inspection process.

[0065] This application does not specifically limit the magnitude of the preset initial exposure energy. In one possible embodiment of this application, the magnitude of the preset initial exposure energy can be 80 millijoules to 120 millijoules; for example, the magnitude of the preset initial exposure energy can be 80 millijoules, 90 millijoules, 100 millijoules, 110 millijoules, or 120 millijoules, etc.

[0066] In one possible embodiment of this application, the initial exposure energy is preset to 100 millijoules.

[0067] This application does not specifically limit the size of the preset step size. In one possible embodiment of this application, the size of the preset step size can be 8 millijoules to 12 millijoules; for example, the size of the preset step size can be 8 millijoules, 9 millijoules, 10 millijoules, 11 millijoules, or 12 millijoules, etc.

[0068] In one possible embodiment of this application, the preset step size is 10 millijoules.

[0069] like Figure 2 As shown, exposure area 101 is a region comprising a column of chips. In one possible embodiment of this application, each exposure area 101 is exposed sequentially column by column along the x-direction. The first exposure area ( ) in the x-direction is exposed with a preset initial exposure energy of 100 millijoules. Figure 2The first exposure is performed on region b (the exposure area 101). Then, during the sequential exposure of each exposure area 101 along the x-direction, a preset step size of 10 millijoules is used. Starting from 100 millijoules, the exposure energy for each subsequent exposure area 101 is 110 millijoules, 120 millijoules, 130 millijoules, 140 millijoules, 150 millijoules, and 160 millijoules. In this way, the inspector can visually observe the gradual change from no exposure to full exposure.

[0070] The lens defect detection method provided in this application does not specifically limit the implementation method of gradually increasing the exposure energy corresponding to the multiple exposure areas 101 along the first direction from a preset initial exposure energy according to a preset step size. As an example, the rules of the Focus-Energy Matrix (FEM) can be followed to make the exposure energy corresponding to the multiple exposure areas 101 gradually increase along the first direction from a preset initial exposure energy according to a preset step size.

[0071] Please see Figure 3 In step S300, after multiple exposures, the presence of a defect in the lens is determined based on whether spot 102 appears on the wafer 100.

[0072] It is understood that in step S300, the wafer 100 may be scanned by a device used for quality inspection and measurement, or the presence of spots 102 on the wafer 100 may be observed by a macroscopic visual inspection by an inspection person.

[0073] In one possible embodiment of this application, the lens defect detection method may further include the following steps:

[0074] If, after multiple exposures, spots 102 appear in at least two exposed areas 101 of the same part of the lens, the lens is deemed to have a defect.

[0075] During the multiple exposures of a 100-point area on the wafer, the same lens is used to expose each exposure area 101. Therefore, if there is a defect in the lens, spots 102 will appear at similar locations on the exposed areas 101 that have been exposed by the lens.

[0076] It is understood that in the above steps, the wafer 100 can be scanned by equipment used for quality inspection and measurement, or the spot 102 can be observed by inspection personnel through macroscopic visual inspection to see whether at least two exposure areas 101 exposed by the same part of the lens after multiple exposures have spots 102.

[0077] In one possible embodiment of this application, a KLA wafer inspection device can be used to scan the wafer 100.

[0078] In one possible embodiment of this application, the lithography machine can be a lithography machine used for fabricating microelectromechanical devices.

[0079] In other words, the detection method provided in the above embodiments can be used to detect whether a lithography machine is suitable for the process of fabricating microelectromechanical devices.

[0080] This application does not specifically limit the types of microelectromechanical devices (MEMS). In one possible embodiment of this application, the microelectromechanical device may include, but is not limited to, thermal infrared detectors.

[0081] Since MEMS thermal infrared detectors are more sensitive to lenses, traditional lithography machine lens defect detection methods are not sensitive enough. The detection method provided in the above embodiments can be used to determine whether a lithography machine is suitable for the process of fabricating MEMS thermal infrared detectors. When a defect is detected in the lens of the current lithography machine, adjustments can be made in a timely manner to avoid producing defective products in the subsequent fabrication. This is beneficial to improving the reliability and production yield of the fabricated MEMS thermal infrared detectors.

[0082] In one possible embodiment of this application, the lithography machine can be a lithography machine from ASML Holding NV (ASML). Specifically, the lithography machine model can be an ASML PAS5500-2000 series i-line lithography machine.

[0083] According to some embodiments, this application also provides a lens defect detection device.

[0084] The lens defect detection device can be used to implement the lens defect detection method provided in any of the foregoing embodiments.

[0085] The lens defect detection device provided in the above embodiments can be used to implement the lens defect detection method provided in the foregoing embodiments. Therefore, by exposing the same wafer with different exposure energies, less obvious defects on the lens can be detected, exhibiting high sensitivity. Moreover, the detection process is simple and easy to implement. By detecting defects in the lens of the lithography machine, adjustments can be made in a timely manner when defects are detected, avoiding the production of defective products and improving the reliability and production yield of the prepared semiconductor structure.

[0086] This application also provides a method for fabricating a semiconductor structure according to some embodiments.

[0087] Please see Figure 4In one possible embodiment of this application, the method for fabricating the semiconductor structure may include the following steps:

[0088] S1: Provides lithography machines.

[0089] S2: The lens of the lithography machine is inspected using the lens defect detection method provided in any of the foregoing embodiments.

[0090] S3: After the lithography machine determines that the lens has no defects, it uses the lithography machine to prepare the semiconductor structure.

[0091] The semiconductor structure fabrication method provided in this application uses the lens defect detection method provided in the aforementioned embodiments to detect the lens of the lithography machine. When a defect is detected in the lens of the current lithography machine, adjustments can be made in a timely manner to avoid producing defective products. This is beneficial to improving the reliability and production yield of the prepared semiconductor structure.

[0092] The semiconductor structure fabrication method provided in this application does not specifically limit the type of lithography machine provided in step S1. In one possible embodiment of this application, the lithography machine can be a lithography machine from ASML Holding NV (ASML). Specifically, the model of the lithography machine can be an ASML PAS5500-2000 series i-line lithography machine.

[0093] It should be understood that, although Figure 1 and Figure 4 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 1 and Figure 4 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0094] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for detecting defects of a lens, characterized by, A method for detecting whether a lens of a photolithography machine has a defect; The method comprises: providing a wafer; performing multiple exposures on the wafer in a region-by-region manner, at least two different exposure energies being used in the multiple exposures; the exposure energies include insufficient exposure energy; after the multiple exposures, judging whether the lens has a defect according to whether a spot appears on the wafer; wherein the wafer comprises a plurality of exposure regions arranged in an array; the exposure region is a region comprising a column of chips; the multiple exposures comprise: exposing the exposure regions one by one or column by column; the lens defect detection method further comprises: after the multiple exposures, if the spot appears on similar positions of at least two exposure regions exposed by the same part of the lens, the lens has a defect. wherein the plurality of exposure regions are arranged in rows along a first direction and in columns along a second direction, the first direction and the second direction intersect; the exposure energy corresponding to the exposure regions in the same column is the same, and the exposure energy corresponding to the exposure regions in multiple columns gradually increases along the first direction.

2. The lens defect detection method according to claim 1, characterized by, The areas of the exposure regions are equal.

3. The lens defect detection method of claim 1, wherein The exposure energy corresponding to the exposure regions in adjacent columns is different.

4. The lens defect detection method of claim 1, wherein The exposure energy corresponding to the exposure regions in multiple columns gradually increases along the first direction from a preset initial exposure energy by a preset step size.

5. The lens defect detection method according to claim 4, characterized by, The preset initial exposure energy is 80-120 mJ.

6. The lens defect detection method according to claim 4, characterized by, The preset step size is 8-12 mJ.

7. An apparatus for detecting defects of a lens, characterized by comprising: The detection device is used to implement the lens defect detection method according to any one of claims 1-6.

8. A method of fabricating a semiconductor structure, characterized by, comprises: providing a photolithography machine; detecting the lens of the photolithography machine by using the lens defect detection method according to any one of claims 1-6; when the photolithography machine is determined to have no defect lens after detection, using the photolithography machine to prepare a semiconductor structure.

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