Wafer warping degree detection method and device, electronic equipment and storage medium

Abstract

The invention relates to a wafer warping degree detection method and device, electronic equipment and a storage medium, and the wafer warping degree detection method comprises the following steps. A wafer to be detected is provided, and a target structure formed by stacking a plurality of layers of thin films is arranged on the surface of one side of the wafer to be detected. A plurality of pieces of detection light with different wave bands are sequentially incident to the target structure, and the reflectivity of the target structure under each piece of detection light is obtained. And determining the warping degree of the wafer to be detected according to the wave band of each detection light and the corresponding reflectivity. According to the wafer warping degree detection method, the warping deformation of the to-be-detected wafer can be detected on the premise that the to-be-detected wafer is not contacted.

Description

Technical Field

[0001] The present disclosure relates to the field of integrated circuit technologies, and in particular, to a method and apparatus for detecting the warpage of a wafer, an electronic device, and a storage medium. Background Art

[0002] With the rapid development of integrated circuit manufacturing technologies, the integration degree of semiconductor devices has been increasing day by day. In the research of three-dimensional semiconductor devices, obtaining devices with smaller critical dimensions through self-aligned double patterning technology is a current popular research direction.

[0003] However, devices with smaller critical dimensions will cause the warpage problem of the wafer to become more and more serious. The self-aligned double patterning technology needs to stack mask and other material layers on the wafer and then transfer the lithography pattern. Therefore, it is very important to detect the warpage deformation of the wafer to be measured without affecting the stacked material layers on the wafer to be measured, so as to improve the self-aligned double patterning technology and further improve the yield of the device.

[0004] Therefore, how to detect the warpage deformation of the wafer to be measured without contacting the wafer to be measured has also become an urgent problem to be solved in the related technologies. Summary of the Invention

[0005] Based on this, the embodiments of the present disclosure provide a method and apparatus for detecting the warpage of a wafer, an electronic device, and a storage medium, which can detect the warpage deformation of the wafer to be measured without contacting the wafer to be measured.

[0006] To achieve the above object, first, some embodiments of the present disclosure provide a method for detecting the warpage of a wafer, including the following steps.

[0007] Provide a wafer to be measured, and a target structure composed of a stack of multiple thin films is provided on one surface of the wafer to be measured.

[0008] Successively irradiate the target structure with a plurality of detection lights having different wavelength bands, and obtain the reflectivity of the target structure under each detection light.

[0009] Determine the warpage of the wafer to be measured according to the wavelength band of each detection light and the corresponding reflectivity.

[0010] In some embodiments of the present disclosure, the method for detecting the warpage of a wafer further includes the following steps.

[0011] Obtain the thickness, refractive index, and extinction coefficient of each thin film in the target structure to determine the optical admittance of the target structure.

[0012] Based on the optical admittance, fit the reflectivity reference curve of the non-warped wafer.

[0013] Among them, according to the wavelength bands of the respective detection lights and the corresponding reflectivities, the warpage of the wafer to be measured is determined, including the following steps.

[0014] According to the wavelength bands of the respective detection lights and the corresponding reflectivities, obtain the reflectivity measurement curve of the wafer to be measured.

[0015] Determine the deviation between the reflectivity measurement curve and the reflectivity reference curve.

[0016] Based on the deviation, determine the warpage of the wafer to be measured.

[0017] In some embodiments of the present disclosure, determining the deviation between the reflectivity measurement curve and the reflectivity reference curve includes the following steps.

[0018] Obtain the reflectivity peaks of the detection lights with the same wavelength band in the reflectivity measurement curve and the reflectivity reference curve.

[0019] Determine the difference between the corresponding reflectivity peaks of the detection lights with the same wavelength band in the reflectivity measurement curve and the reflectivity reference curve and obtain the maximum difference.

[0020] Among them, the maximum difference is the deviation between the reflectivity measurement curve and the reflectivity reference curve.

[0021] In some embodiments of the present disclosure, a plurality of detection lights with different wavelength bands are sequentially incident on the target structure, and the reflectivities of the target structure under the respective detection lights are obtained, including the following steps.

[0022] The reflectometer vertically irradiates the target structure with the detection light.

[0023] The reflectometer receives the reflected light of the detection light from the target structure.

[0024] Determine the reflectivity of the target structure under each detection light according to the reflected light.

[0025] In some embodiments of the present disclosure, the sensor of the reflectometer for receiving the reflected light has a target distance from the target structure.

[0026] Based on the deviation, determining the warpage of the wafer to be measured further includes the following steps.

[0027] According to the deviation and the target distance, determine the warpage of the wafer to be measured.

[0028] In some embodiments of the present disclosure, the determination formula for the warpage of the wafer to be measured includes: Among them, lp is the warpage of the wafer to be measured, R% is the deviation, and d is the target distance.

[0029] An embodiment of the present disclosure also provides a wafer warpage detection device, including a reflection unit and a processing unit. The reflection unit is configured to: sequentially incident a plurality of detection lights with different wavelength bands on a target structure, and obtain the reflectivity of the target structure under each detection light. The processing unit is connected to the reflection unit and is configured to: determine the warpage of the wafer to be measured according to the wavelength bands of the detection lights and the corresponding reflectivities.

[0030] Here, the target structure includes multiple thin films, and the multiple thin films are stacked on one side surface of the wafer to be measured.

[0031] In some embodiments of the present disclosure, the reflection unit includes a reflectometer; the reflectometer includes a light source, a sensor, and a spectrometer. The light source is configured to: vertically incident a detection light on the target structure. The sensor, having a target distance from the target structure, is configured to: receive the reflected light of the detection light by the target structure, and obtain the thickness, refractive index, and extinction coefficient of each layer of thin film in the target structure. The spectrometer is connected to the sensor and is configured to: determine the optical admittance of the target structure according to the thickness, refractive index, and extinction coefficient obtained by the sensor, and fit the reflectivity reference curve of the non-warped wafer based on the optical admittance.

[0032] In some embodiments of the present disclosure, the spectrometer is further configured to: obtain the reflectivity measurement curve of the wafer to be measured according to the wavelength bands of the detection lights and the corresponding reflectivities. The processing unit is further configured to: determine the deviation between the reflectivity measurement curve and the reflectivity reference curve; and determine the warpage of the wafer to be measured based on the deviation.

[0033] In some embodiments of the present disclosure, the processing unit includes a comparison unit. The comparison unit is connected to the spectrometer and is configured to: obtain the reflectivity peaks of the detection lights with the same wavelength band in the reflectivity measurement curve and the reflectivity reference curve; determine the difference between the corresponding reflectivity peaks of the detection lights with the same wavelength band in the reflectivity measurement curve and the reflectivity reference curve, and obtain the maximum difference.

[0034] Wherein, the maximum difference is the deviation between the reflectivity measurement curve and the reflectivity reference curve.

[0035] In some embodiments of the present disclosure, the processing unit further includes a calculation unit. The calculation unit is connected to the comparison unit and is configured to: determine the warpage of the wafer to be measured according to the deviation and the target distance. The determination formula for the warpage of the wafer to be measured includes: Wherein, lp is the warpage of the wafer to be measured, R% is the deviation, and d is the target distance.

[0036] An embodiment of the present disclosure also provides an electronic device, including a memory and a processor. A computer instruction is stored on the memory. When the computer instruction is executed by the processor, the wafer warpage detection method according to any one of the foregoing embodiments is implemented.

[0037] An embodiment of the present disclosure also provides a storage medium storing computer instructions suitable for execution by a processor, and when the computer instructions are executed by the processor, the wafer warpage detection method described in any one of the foregoing embodiments is implemented.

[0038] The embodiments of the present disclosure may / at least have the following advantages:

[0039] The wafer warpage detection method, device, electronic device, and storage medium provided by the embodiments of the present disclosure are as described above. In the embodiments of the present disclosure, a target structure composed of multiple thin film stacks is provided on one surface of the wafer to be measured. By sequentially incident multiple detection lights with different wavelengths on the target structure, and then determining the warpage of the wafer to be measured according to the wavelengths of the detection lights and the corresponding reflectivities. That is, the present disclosure determines the warpage of the wafer to be measured through the reflectivities of multiple detection lights with different incident wavelengths. In this way, when there are multiple thin films on the surface of the wafer to be measured, multiple detection lights with different wavelengths can be sequentially incident on the multiple thin films, and then the warpage deformation of the wafer to be measured can be determined according to the reflectivities of the multiple detection lights. Thus, the present disclosure realizes the detection of the warpage of the wafer without contacting the wafer to be measured. Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0041] Figure 1 It is a flowchart of a wafer warpage detection method provided in an embodiment;

[0042] Figure 2 It is a flowchart of step S20 in a wafer warpage detection method provided in an embodiment;

[0043] Figure 3 It is a flowchart before step S30 in a wafer warpage detection method provided in an embodiment;

[0044] Figure 4 It is a flowchart of step S30 in a wafer warpage detection method provided in an embodiment;

[0045] Figure 5 It is a flowchart of step S32 in a wafer warpage detection method provided in an embodiment;

[0046] Figure 6Schematic cross-sectional view of the structure obtained in step S10 of a wafer warpage detection method provided in an embodiment;

[0047] Figure 7 Schematic cross-sectional view of a structure obtained in step S21 of a wafer warpage detection method provided in an embodiment;

[0048] Figure 8 Schematic cross-sectional view of another structure obtained in step S21 of a wafer warpage detection method provided in an embodiment;

[0049] Figure 9 Schematic cross-sectional view of the structure obtained in step S32 of a wafer warpage detection method provided in an embodiment;

[0050] Figure 10 Schematic structural diagram of a wafer warpage detection device provided in an embodiment;

[0051] Figure 11 Schematic structural diagram of a reflectometer provided in an embodiment;

[0052] Figure 12 Schematic structural diagram of another wafer warpage detection device provided in an embodiment.

[0053] Description of reference numerals:

[0054] 1 - Wafer to be measured; 11 - Warped wafer; 12 - Unwarped wafer; 2 - Target structure; 21 - Mask layer; 22 - Anti-reflection layer; 23 - Photoresist layer; 3 - Reflectometer; 31 - Light source; 32 - Sensor; 33 - Spectrometer; 4 - Spacer; 41 - Connecting fitting; 100 - Reflection unit; 200 - Processing unit; 201 - Comparison unit; 202 - Calculation unit. Detailed implementation manners

[0055] To facilitate the understanding of the present disclosure, the present disclosure will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present disclosure are shown in the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present disclosure more thorough and comprehensive.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs. The terms used in the specification of the present disclosure herein are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0057] It should be understood that when an element or layer is referred to as being "on", "adjacent to", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on", "directly adjacent to", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or portions, these elements, components, regions, layers and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or portion from another element, component, region, layer or portion. Thus, a first element, component, region, layer or portion discussed below may be denoted as a second element, component, region, layer or portion without departing from the teachings of this disclosure.

[0058] Spatial relationship terms such as "under", "below", "lower", "beneath", "above", "upper", etc. are used herein to describe the relationship of one element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relationship terms also encompass different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "under" or "beneath" or "below" another element or feature will be oriented "on" the other element or feature. Thus, the exemplary terms "under" and "beneath" can include both an upper and a lower orientation. Additionally, the device may also assume other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are to be interpreted accordingly.

[0059] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that when the terms "comprises" and / or "comprising" are used in this specification, the presence of the stated features, integers, steps, operations, elements and / or components can be identified, but one or more other features, integers, steps, operations, elements, components and / or groups thereof are not precluded from existence or addition. Also, as used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0060] As used herein, the "deposition" process includes, but is not limited to, physical vapor deposition (PVD), chemical vapor deposition (CVD), or atomic layer deposition (ALD).

[0061] Embodiments of the invention are described herein with reference to cross-sectional views that are schematic illustrations of ideal embodiments (and intermediate structures) of the present disclosure, such that variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances are to be expected. Accordingly, embodiments of the present disclosure should not be limited to the specific shapes of regions shown herein, but include shape deviations due to, for example, manufacturing techniques. For example, an implantation region shown as rectangular typically has rounded or curved features at its edges and / or an implantation concentration gradient, rather than a binary change from the implantation region to the non-implantation region. Similarly, a buried region formed by implantation can result in some implantation in the region between the buried region and the surface through which the implantation occurs. Accordingly, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of the regions of the device and do not limit the scope of the present disclosure.

[0062] With the rapid development of integrated circuit manufacturing technology, the integration level of semiconductor devices has been increasing day by day. In the research of three-dimensional semiconductor devices, obtaining devices with smaller critical dimensions through self-aligned double patterning process is a current popular research direction.

[0063] However, devices with smaller critical dimensions will cause the warpage problem of the wafer to become more and more serious. Wafer warpage will affect the layout alignment performance and cannot produce clear images. At the same time, the adsorption ability of the wafer will also be affected, thereby affecting the progress of the manufacturing process. The self-aligned double patterning process needs to stack mask and other material layers on the wafer and then transfer the lithography pattern. Therefore, it is very important to detect the warpage deformation of the wafer to be tested without affecting the stacked material layer on the wafer to be tested for improving the self-aligned double patterning process and then improving the yield of the device.

[0064] Therefore, how to detect the warpage deformation of the wafer to be tested without contacting the wafer to be tested has also become an urgent problem to be solved in the related technology.

[0065] Based on this, embodiments of the present disclosure provide a method and device for detecting wafer warpage, an electronic device, and a storage medium, which can detect the warpage deformation of the wafer to be tested without contacting the wafer to be tested.

[0066] Please refer to Figure 1 , some embodiments of the present disclosure provide a method for detecting wafer warpage, including steps S10 to S30.

[0067] S10: Provide a wafer to be tested, and a target structure composed of a stack of multiple thin films is provided on one surface of the wafer to be tested.

[0068] S20: Incident multiple detection lights with different wavelength bands on the target structure in sequence, and obtain the reflectivity of the target structure under each detection light.

[0069] S30: Determine the warpage of the wafer to be measured according to the wavelength bands of the respective detection lights and the corresponding reflectivities.

[0070] In the embodiments of the present disclosure, a target structure composed of a multi-layer thin film stack is provided on one surface of the wafer to be measured. By sequentially irradiating the target structure with a plurality of detection lights having different wavelength bands and obtaining the reflectivities, the warpage of the wafer to be measured is determined according to the wavelength bands of the respective detection lights and the corresponding reflectivities. That is, the present disclosure determines the warpage of the wafer to be measured by the reflectivities of a plurality of detection lights having different incident wavelength bands. Thus, in the case where there are multiple thin films on the surface of the wafer to be measured, a plurality of detection lights having different wavelength bands can be sequentially irradiated onto the multi-layer thin films, and then the warpage deformation of the wafer to be measured is determined according to the reflectivities of the plurality of detection lights. Therefore, the present disclosure realizes the detection of the warpage of the wafer without contacting the wafer to be measured.

[0071] In some embodiments of the present disclosure, please refer to Figure 2 , step S20 of sequentially irradiating the target structure with a plurality of detection lights having different wavelength bands and obtaining the reflectivities of the target structure under the respective detection lights includes steps S21 to S23.

[0072] S21: The reflectometer vertically irradiates the detection light onto the target structure.

[0073] S22: The reflectometer receives the reflected light of the detection light from the target structure.

[0074] S23: Determine the reflectivity of the target structure under each detection light according to the reflected light.

[0075] In some embodiments of the present disclosure, please refer to Figure 3 , before step S30, the wafer warpage detection method further includes steps S21' to S22'.

[0076] S21': Obtain the thickness, refractive index, and extinction coefficient of each layer of the thin film in the target structure to determine the optical admittance of the target structure.

[0077] S22': Based on the optical admittance, fit the reflectivity reference curve of the non-warped wafer.

[0078] Correspondingly, in some embodiments of the present disclosure, please refer to Figure 4 , step S30 of determining the warpage of the wafer to be measured according to the wavelength bands of the respective detection lights and the corresponding reflectivities includes steps S31 to S33.

[0079] S31: Obtain the reflectivity measurement curve of the wafer to be measured according to the wavelength bands of the respective detection lights and the corresponding reflectivities.

[0080] S32: Determine the deviation between the reflectivity measurement curve and the reflectivity reference curve.

[0081] S33: Determine the warpage of the wafer to be measured based on the deviation.

[0082] In some embodiments of the present disclosure, refer to Figure 5 , step S32 determines the deviation between the reflectivity measurement curve and the reflectivity reference curve, including steps S321 to S322.

[0083] S321: Obtain the reflectivity peaks of the detection light in the same wavelength band in the reflectivity measurement curve and the reflectivity reference curve.

[0084] S322: Determine the peak difference of the corresponding reflectivities of the detection light in the same wavelength band in the reflectivity measurement curve and the reflectivity reference curve and obtain the maximum difference; wherein, the maximum difference is the deviation between the reflectivity measurement curve and the reflectivity reference curve.

[0085] Exemplarily, the maximum difference is the maximum value of multiple peak differences.

[0086] Step S33 determines the warpage of the wafer to be measured based on the deviation, and further includes the following steps: Determine the warpage of the wafer to be measured according to the deviation and the target distance.

[0087] To more clearly illustrate the wafer warpage detection method in the above - mentioned some embodiments, the following some embodiments exemplarily give some specific implementations of some steps.

[0088] In step S10, refer to Figure 6 , provide a wafer 1 to be measured, and a target structure 2 composed of a stack of multiple thin films is provided on one side surface of the wafer 1 to be measured.

[0089] In some embodiments, the multiple thin films include a mask layer 21, an anti - reflection layer 22, and a photoresist layer 23. That is, the target structure 2 is composed of a stack of the mask layer 21, the anti - reflection layer 22, and the photoresist layer 23. Here, the multiple thin films are not limited to three thin films.

[0090] Exemplarily, the thickness range of the mask layer 21 includes: 60nm - 80nm. For example, the thickness of the mask layer 21 can be 60nm, 65nm, 70nm, 75nm, or 80nm, etc. The thickness range of the anti - reflection layer 22 includes: 15nm - 35nm. For example, the thickness of the anti - reflection layer 22 can be 15nm, 20nm, 25nm, 30nm, or 35nm, etc. The thickness range of the photoresist layer 23 includes: 80nm - 100nm. For example, the thickness of the photoresist layer 23 can be 80nm, 85nm, 90nm, 95nm, or 100nm, etc.

[0091] In step S21, refer to Figure 7 and Figure 8, the reflectometer 3 vertically irradiates the detection light onto the target structure 2.

[0092] In some embodiments, the wafer 1 to be measured with the target structure 2 on its surface can be fixed to the spacer 4 through the connecting fitting 41.

[0093] In some embodiments, the orthographic projection of the reflectometer 3 on the wafer 1 is located at the center of the wafer 1 to be measured.

[0094] In some embodiments, the wafer 1 to be measured includes a warped wafer 11 and an unwarped wafer 12.

[0095] In step S22, please continue to refer to Figure 7 and Figure 8 , the reflectometer 3 receives the reflected light of the detection light by the target structure 2.

[0096] In some embodiments, the distance from the sensor of the reflectometer 3 for receiving the reflected light to the target structure 2 is the target distance d.

[0097] Here, the target distance d is the shortest distance between the sensor of the reflectometer 3 for receiving the reflected light and the surface of the target structure 2.

[0098] In step S23, the reflectivity of the target structure 2 under each detection light is determined according to the reflected light.

[0099] In some embodiments, the reflectometer 3 includes a light source, a sensor, and a spectrometer. Among them, the light source can be a tungsten halogen lamp with a spectral range of 360nm - 2300nm, which is used to vertically irradiate the detection light onto the target structure 2 to provide the wavelengths required for calculating the optical models of different target structures 2. The sensor is used to receive the reflected light of the detection light. The spectrometer is used to determine the reflectivity of the target structure 2 under each detection light according to the reflected light.

[0100] In step S21’, please refer to Figure 8 , obtain the thickness, refractive index, and extinction coefficient of each layer of thin film in the target structure 2 to determine the optical admittance of the target structure 2.

[0101] Here, since the detection light is vertically incident, the reflection angle and refraction angle of the reflected light are zero. Therefore, when the wavelength of the detection light reaches a certain value, the extinction coefficient of the target structure 2 composed of multiple layers of thin films is 0.

[0102] In some embodiments, for multiple layers of thin films, the changes in refractive index and reflectivity during the transmission of light in different media need to be considered. The reflection signals of the reflected light with multiple wavelengths can be obtained through the sensor in the reflectometer 3. The reflection signals include the wavelength lengths of the light vertically incident on the multiple layers of thin films. The optical admittance of the target structure 2 is calculated from the thickness, refractive index, and extinction coefficient of each layer of thin film in the target structure 2. Specifically, the optical admittance can be obtained through the characteristic matrix, and the specific calculation process is as follows:

[0103] Among them, for the stacked structure of the target structure 2, the optical matrices of each stacked layer are combined to obtain the characteristic matrix as follows:

[0104]

[0105]

[0106] N i = n i - ik

[0107] Among them, η m is the substrate or the outgoing medium, N is the complex refractive index, n is the refractive index, K is the extinction coefficient, θ is the angle of the incident light incident on each thin film layer, and d is the thickness of each thin film layer;

[0108] According to the characteristic matrix, the optical admittance of the target structure 2 is:

[0109]

[0110] In step S22’, please refer to Figure 9 , and based on the optical admittance, fit the reflectance reference curve R1 of the un-warped wafer 12.

[0111] Here, the optical admittance can truly characterize the physical properties of light in the multi-layer thin film. Importing the optical admittance into the spectrometer in the reflectometer 3 can fit the reflectance reference curve R1 of the un-warped wafer 12.

[0112] In step S31, according to the wavelength bands of the respective detection lights and the corresponding reflectances, obtain the reflectance measurement curve of the wafer 1 to be measured.

[0113] In some examples, please continue to refer to Figure 9 , when the wafer 1 to be measured is the warped wafer 11, there is a deviation between the reflectance measurement curve R2 of the warped wafer 11 and the reflectance reference curve R1.

[0114] In step S321, please continue to refer to Figure 9 , and obtain the reflectance peaks of the detection lights with the same wavelength band in the reflectance measurement curve R2 and the reflectance reference curve R1.

[0115] In some embodiments, in the reflectance reference curve R1, the reflectance peak of the detection light in a certain wavelength band is A1, and the reflectance peak of the detection light with the same wavelength band in the reflectance measurement curve R2 is A2.

[0116] Here, when the wafer 1 to be measured is warped, the reflectance of the peak of a certain wavelength of the warped wafer 11 decreases to a certain extent compared with that of the un-warped wafer 12.

[0117] In step S322, determine the peak difference of the corresponding reflectance in the reflectance measurement curve R2 and the reflectance reference curve R1 for the detection light of the same wavelength band, and obtain the maximum difference. Among them, the maximum difference is the deviation between the reflectance measurement curve and the reflectance reference curve.

[0118] Exemplarily, the maximum difference is the maximum value of multiple peak differences. For example: the maximum difference is the difference between A1 and A2 (i.e., R%). And use the maximum difference as the deviation R% between the reflectance measurement curve R2 and the reflectance reference curve R1.

[0119] In step S33, determine the warpage lp of the wafer 1 to be measured according to the deviation R% and the target distance d.

[0120] It should be particularly noted that during the simulation, it is found that: there is a positive correlation between the degree of decrease in the reflectance of the wafer 1 to be measured and the degree of warpage, that is, when the measurement distance remains unchanged, the greater the warpage, the greater the degree of decrease in the reflectance at the peak of a certain wavelength.

[0121] In some embodiments, the formula for determining the warpage of the wafer 1 to be measured includes: Among them, lp is the warpage of the wafer 1 to be measured, R% is the deviation, and d is the target distance.

[0122] Exemplarily, when the wafer 1 to be measured is an unwarped wafer 12, the deviation R% is 0, and the warpage lp is 0.

[0123] The embodiments of the present disclosure also provide a wafer warpage detection device for implementing the above-mentioned wafer warpage detection method. The technical effects that the wafer warpage detection device can achieve are the same as those of the wafer warpage detection method in the foregoing embodiments, and will not be elaborated here.

[0124] Please refer to Figure 10 , the wafer warpage detection device includes a reflection unit 100 and a processing unit 200. The reflection unit 100 is configured to: sequentially emit a plurality of detection lights with different wavelength bands to the target structure 2, and obtain the reflectance of the target structure 2 under each detection light. The processing unit 200 is connected to the reflection unit 100 and is configured to: determine the warpage of the wafer 1 to be measured according to the wavelength band of each detection light and the corresponding reflectance.

[0125] Here, the target structure 2 includes a multi-layer thin film, and the multi-layer thin film is stacked on one side surface of the wafer 1 to be measured. In some embodiments, the multi-layer thin film includes a mask layer 21, an anti-reflection layer 22, and a photoresist layer 23. That is, the target structure 2 is composed of a stack of the mask layer 21, the anti-reflection layer 22, and the photoresist layer 23. Here, the multi-layer thin film is not limited to a three-layer thin film.

[0126] Exemplarily, the thickness range of the mask layer 21 includes: 60 nm to 80 nm, the thickness range of the anti-reflection layer 22 includes: 15 nm to 35 nm, and the thickness range of the photoresist layer 23 includes: 80 nm to 100 nm.

[0127] In some embodiments, referring to Figure 7 and Figure 8 , the reflection unit 100 includes a reflectometer 3. The reflectometer 3 is used for the sensor that receives the reflected light to have a target distance d from the target structure 2. Here, the target distance d is the shortest distance between the sensor of the reflectometer 3 that receives the reflected light and the surface of the target structure 2.

[0128] In some examples, referring to Figure 11 , the reflectometer 3 includes a light source 31, a sensor 32, and a spectrometer 33. The light source 31 is configured to: vertically incident the detection light on the target structure. The sensor 32, having a target distance d from the target structure 2, is configured to: receive the reflected light of the detection light from the target structure 2 and obtain the thickness, refractive index, and extinction coefficient of each thin film layer in the target structure 2. The spectrometer 33 is connected to the sensor 32 and is configured to: determine the optical admittance of the target structure 2 according to the thickness, refractive index, and extinction coefficient obtained by the sensor 32, and based on the optical admittance, fit the reflectance reference curve of the un-warped wafer 12.

[0129] Among them, the light source can be a tungsten halogen lamp, with a spectral range of 360 nm - 2300 nm, used to vertically incident the detection light on the target structure 2 to provide the wavelengths required for calculating the optical models of different target structures 2. The sensor is used to receive the reflected light of the detection light. The spectrometer is used to determine the reflectance of the target structure 2 under each detection light according to the reflected light.

[0130] In some embodiments, the orthographic projection of the reflectometer 3 on the wafer 1 is located at the center of the wafer 1 to be measured.

[0131] In some embodiments, the wafer 1 to be measured includes a warped wafer 11 and an un-warped wafer 12.

[0132] In some embodiments, the spectrometer 33 is further configured to: obtain the reflectance measurement curve of the wafer 1 to be measured according to the wavelength bands of each detection light and the corresponding reflectances. The processing unit 200 is further configured to: determine the deviation R% between the reflectance measurement curve R2 and the reflectance reference curve R1; based on the deviation R%, determine the warpage degree lp of the wafer to be measured.

[0133] In some embodiments, referring to Figure 12, the processing unit 200 includes a comparison unit 201. The comparison unit 201 is connected to the spectrometer 33 and is configured to: obtain the reflectance peaks of the detected light in the same wavelength band in the reflectance measurement curve R2 and the reflectance reference curve R1; determine the peak difference of the corresponding reflectances of the detected light in the same wavelength band in the reflectance measurement curve R2 and the reflectance reference curve R1 and obtain the maximum difference. Among them, the maximum difference is the deviation between the reflectance measurement curve and the reflectance reference curve.

[0134] Please refer to Figure 9 , in some embodiments, in the reflectance reference curve R1, the reflectance peak of the detected light in a certain wavelength band is A1, and the reflectance peak of the detected light in the same wavelength band in the reflectance measurement curve R2 is A2.

[0135] Exemplarily, the maximum difference is the maximum value of multiple peak differences. For example: the maximum difference is the deviation between A1 and A2.

[0136] In some embodiments, the processing unit 200 further includes a calculation unit 202. The calculation unit 202 is connected to the comparison unit 201 and is configured to: determine the warpage lp of the wafer 1 to be measured according to the deviation R% and the target distance d. The determination formula of the warpage lp of the wafer 1 to be measured includes: where lp is the warpage of the wafer 1 to be measured, R% is the deviation, and d is the target distance.

[0137] The embodiments of the present disclosure also provide an electronic device, including a memory and a processor. A computer instruction is stored on the memory. When the computer instruction is executed by the processor, the wafer warpage detection method described in any one of the foregoing embodiments is implemented.

[0138] The embodiments of the present disclosure also provide a storage medium, characterized in that the storage medium stores computer instructions suitable for being executed by a processor, and when the computer instructions are executed by the processor, the wafer warpage detection method described in any one of the foregoing embodiments is implemented.

[0139] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), floppy disks, flash memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processing units, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., and are not limited thereto.

[0140] In the above storage medium and electronic device, when the computer instruction is executed by the processor, the wafer warpage detection method described in any one of the foregoing solutions is adopted. Thus, the above storage medium and electronic device for wafer warpage detection can detect the warpage deformation of the wafer to be measured without contacting the wafer to be measured.

[0141] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features of the above embodiments are described. However, as long as these combinations of technical features do not conflict, they should be considered to be within the scope described in this specification.

[0142] The above embodiments only represent several implementation manners of the present disclosure. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present disclosure, several modifications and improvements can still be made, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the patent of the present disclosure should be subject to the appended claims.

Claims

1. A method for detecting the warpage of a wafer, characterized in that, Including: Providing a wafer to be measured, on one side surface of which there is a target structure composed of a stack of multiple thin films; Successively irradiating the target structure with multiple detection lights having different wavelength bands, and obtaining the reflectivity of the target structure under each of the detection lights; Determining the warpage of the wafer to be measured according to the wavelength bands of the detection lights and the corresponding reflectivities.

2. The method for detecting the warpage of a wafer according to claim 1, characterized in that, Further including: Obtaining the thickness, refractive index and extinction coefficient of each layer of the thin films in the target structure to determine the optical admittance of the target structure; Fitting a reflectivity reference curve of an unwarped wafer based on the optical admittance; Wherein, the determining the warpage of the wafer to be measured according to the wavelength bands of the detection lights and the corresponding reflectivities includes: Obtaining a reflectivity measurement curve of the wafer to be measured according to the wavelength bands of the detection lights and the corresponding reflectivities; Determining the deviation between the reflectivity measurement curve and the reflectivity reference curve; Determining the warpage of the wafer to be measured based on the deviation.

3. The method for detecting the warpage of a wafer according to claim 2, characterized in that, The determining the deviation between the reflectivity measurement curve and the reflectivity reference curve includes: Obtaining the reflectivity peaks of the detection lights with the same wavelength band in the reflectivity measurement curve and the reflectivity reference curve; Determining the difference between the reflectivity peaks corresponding to the detection lights with the same wavelength band in the reflectivity measurement curve and the reflectivity reference curve and obtaining the maximum difference; Wherein, the maximum difference is the deviation between the reflectivity measurement curve and the reflectivity reference curve.

4. The method for detecting the warpage of a wafer according to claim 2, characterized in that, The successively irradiating the target structure with multiple detection lights having different wavelength bands and obtaining the reflectivity of the target structure under each of the detection lights includes: The reflectometer vertically irradiates the target structure with the detection light; The reflectometer receives the reflected light of the detection light by the target structure; Determining the reflectivity of the target structure under each of the detection lights according to the reflected light.

5. The method for detecting the warpage of a wafer according to claim 4, characterized in that, The sensor of the reflectometer for receiving the reflected light has a target distance from the target structure; The determining the warpage of the wafer to be measured based on the deviation further includes: Determining the warpage of the wafer to be measured according to the deviation and the target distance.

6. The method for detecting the warpage of a wafer according to claim 5, characterized in that, The determining formula for the warpage of the wafer to be measured includes: Wherein, lp is the warpage of the wafer to be measured, R% is the deviation, and d is the target distance.

7. A device for detecting the warpage of a wafer, characterized in that, Including: A reflection unit configured to: successively irradiate the target structure with multiple detection lights having different wavelength bands, and obtain the reflectivity of the target structure under each of the detection lights; the target structure includes a stack of multiple thin films, and the stack of multiple thin films is disposed on one side surface of the wafer to be measured; A processing unit connected to the reflection unit and configured to: determine the warpage of the wafer to be measured according to the wavelength bands of the detection lights and the corresponding reflectivities.

8. The device for detecting the warpage of a wafer according to claim 7, characterized in that, The reflection unit includes a reflectometer; the reflectometer includes: A light source configured to: vertically irradiate the target structure with the detection light; A sensor having a target distance from the target structure and configured to: receive the reflected light of the detection light by the target structure, and obtain the thickness, refractive index and extinction coefficient of each layer of the thin films in the target structure; A spectrometer, connected to the sensor, is configured to: determine the optical admittance of the target structure according to the thickness, refractive index, and extinction coefficient obtained by the sensor, and fit a reflectance reference curve of the unwarped wafer based on the optical admittance.

9. The wafer warpage detection device according to claim 8, wherein, The spectrometer is further configured to: obtain a reflectance measurement curve of the wafer to be measured according to the wavelength bands of the detection lights and the corresponding reflectances. The processing unit is further configured to: determine the deviation between the reflectance measurement curve and the reflectance reference curve; and determine the warpage degree of the wafer to be measured based on the deviation.

10. The wafer warpage detection device according to claim 9, wherein, The processing unit includes: A comparison unit, connected to the spectrometer, is configured to: Obtain the reflectance peaks of the detection lights in the same wavelength band in the reflectance measurement curve and the reflectance reference curve. Determine the difference between the reflectance peaks corresponding to the detection lights in the same wavelength band in the reflectance measurement curve and the reflectance reference curve and obtain the maximum difference. Wherein, the maximum difference is the deviation between the reflectance measurement curve and the reflectance reference curve.

11. The wafer warpage detection device according to claim 10, wherein, The processing unit further includes: A calculation unit, connected to the comparison unit, is configured to: determine the warpage degree of the wafer to be measured according to the deviation and the target distance. The determination formula for the warpage degree of the wafer to be measured includes: Wherein, lp is the warpage degree of the wafer to be measured, R% is the deviation, and d is the target distance.

12. An electronic device, wherein, It includes a memory and a processor; computer instructions are stored on the memory; when the computer instructions are executed by the processor, the wafer warpage degree detection method according to any one of claims 1 to 6 is implemented.

13. A storage medium, wherein, The storage medium stores computer instructions suitable for being executed by a processor, and when the computer instructions are executed by the processor, the wafer warpage degree detection method according to any one of claims 1 to 6 is implemented.

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