Photoetching alignment method

Abstract

The invention provides a photoetching alignment method, and relates to the technical field of semiconductor processes. Based on the first groove and the second groove of the mask layer, enabling the metal layer to form a similar conformal shape with the second groove in the preparation process of the metal layer; in the preparation process of the first non-light-transmitting film layer, the first non-light-transmitting film layer also forms a shape similar to the shape of the second groove; a photoresist layer and a second non-light-transmitting film layer are sequentially formed, the surfaces of the sides, away from the substrate, of the photoresist layer and the second non-light-transmitting film layer are parallel to the plane where the substrate is located, and at the moment, the thickness of the photoresist layer corresponding to the core area pattern is smaller than the thickness of the photoresist layer corresponding to the alignment mark pattern; the photoresist layers with different thicknesses have different signal responses in the measurement process of the diffraction light efficiency, so that the aim of accurately positioning and aligning the position of the identification pattern is fulfilled.

Description

Technical Field

[0001] The present application relates to the field of semiconductor process technology, and in particular to a photolithography alignment method. Background Art

[0002] In the process of integrated circuit manufacturing, as the core structure becomes smaller and smaller, the thickness of the film layer becomes thinner and thinner, and the chemical mechanical polishing technology is widely used, it is difficult to transfer the graphic morphology features in the manufacturing process through the film.

[0003] When there is opaque material between the alignment mark pattern of the front layer and the photoresist, it is difficult to detect the alignment mark pattern of the front layer during the lithography alignment detection process, and the lithography machine cannot perform alignment operations and subsequent exposure operations. Summary of the invention

[0004] In view of the above problems, the present application provides a photolithography alignment method to achieve the purpose of accurately locating the alignment mark pattern position. The specific scheme is as follows:

[0005] A first aspect of the present application provides a photolithography alignment method, the photolithography alignment method comprising:

[0006] A structure to be processed is provided, the structure to be processed comprising a substrate and a mask layer located on one side of the substrate; the mask layer has a core area pattern and an alignment mark pattern; the core area pattern has a first groove, and the alignment mark pattern has a second groove;

[0007] forming a metal layer, wherein the metal layer fills the first groove and covers the sidewall and the bottom of the second groove; the thickness of the metal layer at the bottom of the second groove is less than the depth of the second groove;

[0008] forming a first non-light-transmitting film layer, wherein the first non-transparent film layer comprises a first concave region that is concave toward one side of the substrate; an orthographic projection of the first concave region on the substrate is located within an orthographic projection of the second groove on the substrate;

[0009] forming a photoresist layer on a side of the first non-light-transmissive film layer away from the substrate, wherein a surface of the photoresist layer away from the substrate is parallel to a plane where the substrate is located;

[0010] forming a second non-light-transmitting film layer on a side of the photoresist layer away from the substrate, wherein a surface of the second non-light-transmitting film layer on a side away from the substrate is parallel to a plane where the substrate is located;

[0011] The diffraction light efficiency is measured on a side of the second light-impermeable film layer facing away from the substrate to determine the position of the alignment mark pattern.

[0012] Preferably, in the above-mentioned photolithography alignment method, the width of the first groove is less than or equal to 200 nanometers.

[0013] Preferably, in the above-mentioned photolithography alignment method, the width of the second groove is greater than or equal to 1 micron.

[0014] Preferably, in the above-mentioned photolithography alignment method, the thickness of the mask layer ranges from 50 nanometers to 500 nanometers.

[0015] Preferably, in the above-mentioned photolithography alignment method, the forming of the metal layer comprises:

[0016] forming a metal layer on a side of the mask layer away from the substrate, the metal layer comprising a second recessed region recessed toward the substrate side; an orthographic projection of the second recessed region on the substrate is located within an orthographic projection of the second groove on the substrate;

[0017] The metal layer is processed based on a CMP process so that the metal layer fills the first groove and covers the sidewall and bottom of the second groove; the thickness of the metal layer at the bottom of the second groove is less than the depth of the second groove.

[0018] Preferably, in the above-mentioned photolithography alignment method, the structure to be processed further comprises:

[0019] A first protection layer is located between the substrate and the mask layer.

[0020] Preferably, in the above-mentioned photolithography alignment method, before forming the first light-impermeable film layer, the photolithography alignment method further comprises:

[0021] A second protective layer is formed, wherein the second protective layer comprises a third recessed area recessed toward one side of the substrate; an orthographic projection of the third recessed area on the substrate is located within an orthographic projection of the second groove on the substrate.

[0022] Preferably, in the above-mentioned photolithography alignment method, before forming the photoresist layer, the photolithography alignment method further comprises:

[0023] forming a dielectric material layer, wherein the dielectric material layer comprises a fourth recessed region recessed toward one side of the substrate; an orthographic projection of the fourth recessed region on the substrate is located within an orthographic projection of the second groove on the substrate;

[0024] Wherein, the refractive index of the dielectric material layer is different from the refractive index of the first non-light-transmissive film layer.

[0025] Preferably, in the above-mentioned photolithography alignment method, the material of the metal layer is Cu material or Al material.

[0026] Preferably, in the above-mentioned photolithography alignment method, the material of the first non-light-transmitting film layer is Ag material or Al material;

[0027] The material of the second non-light-transmitting film layer is Ag material or Al material.

[0028] By means of the above technical scheme, the present application provides a photolithography alignment method, which is based on the first groove and the second groove of the mask layer. During the preparation of the metal layer, the first groove is filled and the side wall and the bottom of the second groove are covered. The thickness of the metal layer at the bottom of the second groove is less than the depth of the second groove, forming a conformal morphology similar to the second groove; during the preparation of the first non-light-transmitting film layer, the orthographic projection of the first recessed area of ​​the first non-transparent film layer on the substrate is located within the orthographic projection of the second groove on the substrate, also forming a conformal morphology similar to the second groove; then, a photoresist layer and a second non-light-transmitting film layer are formed in sequence, and the surfaces of the photoresist layer and the second non-light-transmitting film layer facing away from the substrate are parallel to the plane where the substrate is located. At this time, the thickness of the photoresist layer corresponding to the core area pattern will be less than the thickness of the photoresist layer corresponding to the alignment mark pattern; in the measurement process of the diffraction light efficiency, photoresist layers of different thicknesses have different signal responses, thereby achieving the purpose of accurately locating the position of the alignment mark pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0030] Figure 1 A schematic diagram of a process flow of a photolithography alignment method provided by an embodiment of the present invention;

[0031] Figure 2-Figure 9 for Figure 1 A schematic diagram of a portion of the structure corresponding to the photolithography alignment method shown;

[0032] Fig.10 A schematic diagram of a curve showing the relationship between mask layer thickness and normalized diffraction light efficiency provided by an embodiment of the present invention;

[0033] Fig.11 Another structural schematic diagram corresponding to a photolithography alignment method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation mode of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. It is known to those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] It should be noted that the directional words appearing in the present invention are based on the relative position relationship shown in the drawings and cannot be used as an absolute limitation to the present application.

[0037] refer to Figure 1 , Figure 1 A schematic diagram of a process flow of a photolithography alignment method provided by an embodiment of the present invention. A photolithography alignment method provided by an embodiment of the present invention comprises:

[0038] S101: Figure 2 As shown, a structure to be processed is provided, which includes a substrate 11 and a mask layer 12 located on one side of the substrate 11; the mask layer has a core area pattern and an alignment mark pattern; the core area pattern has a first groove 13, and the alignment mark pattern has a second groove 14.

[0039] Specifically, in the embodiment of the present invention, the mask layer 12 includes but is not limited to a hard mask layer, and the thickness of the mask layer 12 is 50 nanometers to 500 nanometers; exemplary, the thickness of the mask layer 12 is 50 nanometers, 78 nanometers, 200 nanometers, 264 nanometers or 500 nanometers. The width W01 of the first groove 13 is less than or equal to 200 nanometers; exemplary, the width W01 of the first groove 13 is 200 nanometers, 146 nanometers or 75 nanometers. The width W02 of the second groove 14 is greater than or equal to 1 micrometer; exemplary, the width W02 of the second groove 14 is 1 micrometer, 3.5 micrometers or 8 micrometers.

[0040] It should be noted that, for the alignment mark pattern, when there is a gap with a width greater than 1 micron, the corresponding portion of the mask layer 12 can also be finely divided according to the size of the core area pattern, that is, the pattern in the alignment mark pattern except the second groove 14 can be secondarily finely subdivided according to the width of the first groove 13.

[0041] The material of the mask layer 12 includes but is not limited to dielectric materials such as silicon oxide and silicon nitride, and needs to have good electrical insulation. The mask layer 12 serves as a subsequent metal isolation layer.

[0042] In an optional embodiment of the present invention, Figure 3 As shown, the structure to be processed also includes:

[0043] A first protection layer 15 is located between the substrate 11 and the mask layer 12 .

[0044] Since a metal layer will be formed in the subsequent process, in order to avoid diffusion of metal elements in the metal layer and ensure the film quality of the metal layer, a protective layer, namely a first protective layer 15, is provided between the substrate 11 and the mask layer 12 to protect the bottom of the metal layer.

[0045] S102: Figure 4 and Figure 5 As shown, a metal layer 16 is formed, the metal layer 16 fills the first groove 13 , and the metal layer 16 covers the sidewall and bottom of the second groove 14 ; the thickness of the metal layer 16 at the bottom of the second groove 14 is less than the depth of the second groove 14 .

[0046] Optionally, in the embodiment of the present invention, a possible way to form the metal layer 16 is:

[0047] like Figure 4 As shown, a metal layer 16 is formed on the side of the mask layer 12 facing away from the substrate 11 , and the metal layer 16 includes a second recessed area 17 recessed toward the side of the substrate 11 ; the orthographic projection of the second recessed area 17 on the substrate 11 is located within the orthographic projection of the second groove 14 on the substrate 11 .

[0048] like Figure 5 As shown, the metal layer 16 is processed based on the CMP process so that the metal layer 16 fills the first groove 13 and covers the sidewall and bottom of the second groove 14; the thickness of the metal layer 16 located at the bottom of the second groove 14 is less than the depth of the second groove 14.

[0049] Specifically, the material of the metal layer 16 includes but is not limited to Cu material or Al material, and includes but is not limited to the use of an electroplating process to form the metal layer 16. The thickness of the metal layer 16 in different regions can be controlled by controlling the parameters in the electroplating process. Figure 4 As shown, the cut-off time of the metal layer 16 covering the structure can be accurately controlled according to the time of the metal layer 16 electroplating process, so that it appears as shown in FIG. Figure 4The conformal effect shown in the figure is achieved. That is, good filling is achieved in the core area pattern, and conformal features are achieved in the alignment mark pattern. In an ideal case, the cross-sectional shape of the second recessed area 17 is the same as the cross-sectional shape of the second groove 14, but the size of the cross-sectional shape of the second recessed area 17 is smaller than the size of the cross-sectional shape of the second groove 14.

[0050] In order to ensure that the metal layer 16 can completely fill the area where the first groove 13 is located, Figure 4 As shown, during the electroplating process of the metal layer 16 , a portion of the metal layer 16 will be deposited more thickly, and at this time, the metal layer 16 will completely cover the exposed surface of the mask layer 12 .

[0051] Afterwards, if Figure 5 As shown, including but not limited to using a CMP process to process the metal layer 16, so as to remove the metal layer 16 above the mask layer 12, so that the metal layer 16 fills the first groove 13, and the metal layer 16 covers the side wall and the bottom of the second groove 14, and the thickness of the metal layer 16 at the bottom of the second groove 14 is less than the depth of the second groove 14, so as to obtain a film layer structure with different characteristics.

[0052] Among them, the film layer structure with different characteristics means that the metal layer 16 of the core area pattern can be well filled into the first groove 13, and the thickness of the metal layer 16 located in the first groove 13 is the same as the depth of the first groove 13; the metal layer 16 of the alignment mark pattern covers the side wall and the bottom of the second groove 14, and the thickness of the metal layer 16 located at the bottom of the second groove 14 is less than the depth of the second groove 14, forming a structure conformal to the second groove 14, and a step morphology appears.

[0053] In an optional embodiment of the present invention, Figure 6 As shown, before forming the first non-light-transmitting film layer, the photolithography alignment method further includes:

[0054] A second protective layer 18 is formed, and the second protective layer 18 includes a third recessed area 19 recessed toward one side of the substrate 11 ; the orthographic projection of the third recessed area 19 on the substrate 11 is located within the orthographic projection of the second groove 14 on the substrate 11 .

[0055] In order to avoid diffusion of metal elements in the metal layer 16 and ensure the film quality of the metal layer 16 , after the metal layer 16 is prepared, a protective layer, namely a second protective layer 18 , is disposed on top of the metal layer 16 to protect the top of the metal layer 16 .

[0056] Based on the arrangement of the first protective layer 15 and the second protective layer 18 , combined with the mask layer 12 , all-round protection of the metal layer 16 can be achieved, thereby maximizing the film quality of the metal layer 16 .

[0057] based on Figure 5 The morphological features of the film layer shown in FIG. 1 are as follows. The prepared second protective layer 18 also has a third concave region 19 that is concave toward the substrate 11 side, so that it appears as shown in FIG. Figure 6 The conformal effect shown in FIG. 1 is that a good planar film layer feature is achieved in the core area pattern, and a conformal feature is achieved in the alignment mark pattern. In an ideal case, the cross-sectional shape of the third recessed area 19 is the same as the cross-sectional shape of the second groove 14, but the size of the cross-sectional shape of the third recessed area 19 is smaller than the size of the cross-sectional shape of the second groove 14, and smaller than the size of the cross-sectional shape of the second recessed area 17.

[0058] The thickness of the second protective layer 18 ranges from 5 nanometers to 200 nanometers. Exemplarily, the thickness of the second protective layer 18 is 5 nanometers, 60 nanometers, 124 nanometers, or 200 nanometers.

[0059] S103: Figure 7 As shown, a first non-light-transmitting film layer 20 is formed, and the first non-transparent film layer 20 includes a first recessed area 21 recessed toward one side of the substrate 11; the orthographic projection of the first recessed area 21 on the substrate 11 is located within the orthographic projection of the second groove 14 on the substrate 11.

[0060] Specifically, the material of the first non-light-transmitting film layer 20 includes but is not limited to Ag material or Al material, and includes but is not limited to forming the first non-light-transmitting film layer 20 by metal sputtering. The thickness of the first non-light-transmitting film layer 20 is less than or equal to 50 nanometers.

[0061] based on Figure 6 The morphological characteristics of the film layer shown in FIG. 1 are as follows. The first non-light-transmitting film layer 20 prepared also has a first concave region 21 that is concave toward the side of the substrate 11, so that it appears as shown in FIG. Figure 7 The conformal effect shown in FIG. 1 is that a good planar film layer feature is achieved in the core area pattern, and a conformal feature is achieved in the alignment mark pattern. In an ideal case, the cross-sectional shape of the first recessed area 21 is the same as the cross-sectional shape of the second groove 14, but the size of the cross-sectional shape of the first recessed area 21 is smaller than the size of the cross-sectional shape of the second groove 14, and smaller than the size of the cross-sectional shape of the second recessed area 17, and smaller than the size of the cross-sectional shape of the third recessed area 19.

[0062] S104: Figure 8As shown, a photoresist layer 22 is formed on the side of the first non-light-transmissive film layer 20 away from the substrate 11 , and the surface of the photoresist layer 22 away from the substrate 11 is parallel to the plane where the substrate 11 is located.

[0063] Specifically, the method includes but is not limited to preparing the photoresist layer 22 by spin coating with a coating machine, and the top height of the prepared photoresist layer 22 is consistent. It can be understood that the surface of the photoresist layer 22 facing away from the substrate 11 is parallel to the plane where the substrate 11 is located. At this time, the thickness of the photoresist layer 22 corresponding to the core area pattern will be less than the thickness of the photoresist layer 22 corresponding to the alignment mark pattern.

[0064] S105: Fig. 9 As shown, a second non-light-transmitting film layer 23 is formed on the side of the photoresist layer 22 away from the substrate 11 , and a surface of the second non-light-transmitting film layer 23 away from the substrate 11 is parallel to the plane where the substrate 11 is located.

[0065] Specifically, the material of the second non-light-transmitting film layer 23 includes but is not limited to Ag material or Al material, and includes but is not limited to forming the second non-light-transmitting film layer 23 by metal sputtering. The thickness of the second non-light-transmitting film layer 23 is less than or equal to 50 nanometers.

[0066] In an optional embodiment of the present invention, the thickness of the first non-light-transmitting film layer 20 and the second non-light-transmitting film layer 23 are both 30 nanometers, and the thickness of the photoresist layer 22 is 50 nanometers.

[0067] based on Fig. 9 As for the structure shown in the figure, in the sandwich structure of the first non-light-transmitting film layer 20, the photoresist layer 22 and the second non-light-transmitting film layer 23, the photoresist layer 22 corresponding to the core area pattern and the alignment mark pattern has different thickness characteristics. That is, the thickness of the photoresist layer 22 corresponding to the core area pattern is less than the thickness of the photoresist layer 22 corresponding to the alignment mark pattern. In the subsequent measurement process of the diffraction light efficiency, the photoresist layers 22 with different thicknesses have different signal responses, thereby achieving the purpose of accurately locating the position of the alignment mark pattern.

[0068] S106: measuring the diffraction light efficiency on the side of the second light-impermeable film layer 23 facing away from the substrate 11 to determine the position of the alignment mark pattern.

[0069] Specifically, in the embodiments of the present invention, refer to Fig.10 , Fig.10A schematic diagram of a curve showing the relationship between the thickness of a mask layer and the normalized diffraction light efficiency provided by an embodiment of the present invention. Due to the sandwich structure of the first non-light-transmitting film layer 20, the photoresist layer 22 and the second non-light-transmitting film layer 23, the photoresist layer 22 corresponding to the core area pattern and the alignment mark pattern has different thickness characteristics. That is, the thickness of the photoresist layer 22 corresponding to the core area pattern will be less than the thickness of the photoresist layer 22 corresponding to the alignment mark pattern. In the subsequent measurement process of the diffraction light efficiency, the photoresist layers 22 of different thicknesses have different signal responses, and the signal is further regulated by optimizing the thickness of the mask layer 12, so as to achieve the purpose of accurately locating the position of the alignment mark pattern.

[0070] The measurement of diffraction light efficiency refers to the measurement of diffraction light efficiency, especially the first-order diffraction light efficiency. Normalized diffraction light efficiency is used for evaluation, and usually the diffraction light efficiency is required to exceed 0.1%. Fig.10 As shown, the change in the thickness of the mask layer 12 causes the diffraction light efficiency to change. When the thickness of the mask layer 12 is 210 nanometers, the maximum diffraction light efficiency, which is 115%, occurs. The diffraction light detection wavelength used in this embodiment is 633 nanometers. Optionally, any wavelength of light within the range of 400 nanometers to 900 nanometers can be used for detection. In particular, when the detection light wavelength is changed, the thickness of the mask layer 12 should be optimized.

[0071] When the thickness of the mask layer 12 is greater than 147 nanometers and less than 268 nanometers, the first-order diffraction light efficiency is greater than 0.1%; when the thickness of the mask layer 12 is greater than 184 nanometers and less than 236 nanometers, the first-order diffraction light efficiency is greater than 1%.

[0072] During feedback, the thickness of the mask layer 12 should be controlled within the range of [147, 268] nanometers to achieve a normalized diffraction light efficiency of 0.1%; the thickness of the mask layer 12 is controlled within the range of [184, 236] nanometers to achieve a normalized diffraction light efficiency of 1%.

[0073] When the alignment mark pattern of the front layer is difficult to detect in the alignment detection process, the technical solution of the present application can be used to ensure that the photoresist layer 22 corresponding to the core area pattern and the alignment mark pattern has different thickness characteristics, and excellent alignment efficiency can be achieved by optimizing the thickness of the mask layer 12.

[0074] In addition, the technical solution of the present application ensures the filling quality of the metal layer 16 of the core area graphic, and ensures the conformal characteristics of the partial film layer to the alignment mark graphic, that is, it does not affect the imaging quality requirements of the core area, and does not require additional processes in the area of ​​the alignment mark graphic, such as additional photolithography processes to achieve etching and removal of the opaque film layer.

[0075] In an optional embodiment of the present invention, reference Fig.11 , Fig.11 Another structural schematic diagram corresponding to a photolithography alignment method provided by an embodiment of the present invention. Since the size of the second groove 14 of the alignment mark pattern is in the order of micrometers, a feature conforming to the second groove 14 will appear after the photoresist layer 22 is prepared, and a feature conforming to the second groove 14 will also appear after the second non-light-transmitting film layer 23 is prepared. If this feature can be clearly extracted, there is no need to additionally control the thickness of the mask layer 12, and the position of the alignment mark pattern can be intuitively identified.

[0076] In an optional embodiment of the present invention, before forming the photoresist layer 22, the photolithography alignment method further includes:

[0077] A dielectric material layer is formed, the dielectric material layer comprising a fourth recessed area recessed toward one side of the substrate 11; the orthographic projection of the fourth recessed area on the substrate 11 is located within the orthographic projection of the second groove 14 on the substrate 11; wherein the refractive index of the dielectric material layer is different from the refractive index of the first non-light-transmitting film layer 20.

[0078] Specifically, in the embodiment of the present invention, after the first non-light-transmitting film layer 20 is prepared, other materials can be deposited and chemically mechanically polished to achieve a flat surface feature, and then a photoresist layer 22 and a second non-light-transmitting film layer 23 are prepared. The refractive index of the dielectric material layer is different from that of the first non-light-transmitting film layer 20 to achieve an optical signal difference, and in the process of measuring the diffraction light efficiency, the position of the alignment mark pattern can be determined more accurately.

[0079] The above is a detailed introduction to a lithography alignment method provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0080] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between 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 method part description.

[0081] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device that includes a series of elements is inherent to the elements, or also includes elements inherent to these processes, methods, articles or devices. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device that includes the elements.

[0082] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photolithography alignment method, characterized in that: The photolithography alignment method comprises: A structure to be processed is provided, the structure to be processed comprising a substrate and a mask layer located on one side of the substrate; the mask layer has a core area pattern and an alignment mark pattern; the core area pattern has a first groove, and the alignment mark pattern has a second groove; forming a metal layer, wherein the metal layer fills the first groove and covers the sidewall and the bottom of the second groove; the thickness of the metal layer at the bottom of the second groove is less than the depth of the second groove; forming a first non-light-transmitting film layer, wherein the first non-transparent film layer comprises a first concave region that is concave toward one side of the substrate; an orthographic projection of the first concave region on the substrate is located within an orthographic projection of the second groove on the substrate; forming a photoresist layer on a side of the first non-light-transmissive film layer away from the substrate, wherein a surface of the photoresist layer away from the substrate is parallel to a plane where the substrate is located; forming a second non-light-transmitting film layer on a side of the photoresist layer away from the substrate, wherein a surface of the second non-light-transmitting film layer on a side away from the substrate is parallel to a plane where the substrate is located; The diffraction light efficiency is measured on a side of the second light-impermeable film layer facing away from the substrate to determine the position of the alignment mark pattern.

2. The photolithography alignment method according to claim 1, characterized in that: The width of the first groove is less than or equal to 200 nanometers.

3. The photolithography alignment method according to claim 1, characterized in that: The width of the second groove is greater than or equal to 1 micrometer.

4. The photolithography alignment method according to claim 1, characterized in that: The thickness of the mask layer ranges from 50 nanometers to 500 nanometers.

5. The photolithography alignment method according to claim 1, characterized in that: The forming of the metal layer comprises: forming a metal layer on a side of the mask layer away from the substrate, the metal layer comprising a second recessed area recessed toward the substrate side; the orthographic projection of the second recessed area on the substrate is located within the orthographic projection of the second groove on the substrate; The metal layer is processed based on a CMP process so that the metal layer fills the first groove and covers the sidewall and bottom of the second groove; the thickness of the metal layer at the bottom of the second groove is less than the depth of the second groove.

6. The photolithography alignment method according to claim 1, characterized in that: The structure to be processed also includes: A first protection layer is located between the substrate and the mask layer.

7. The photolithography alignment method according to claim 1, characterized in that: Before forming the first non-light-transmitting film layer, the photolithography alignment method further includes: A second protective layer is formed, wherein the second protective layer comprises a third recessed area recessed toward one side of the substrate; an orthographic projection of the third recessed area on the substrate is located within an orthographic projection of the second groove on the substrate.

8. The photolithography alignment method according to claim 1, characterized in that: Before forming the photoresist layer, the photolithography alignment method further comprises: forming a dielectric material layer, wherein the dielectric material layer comprises a fourth recessed region recessed toward one side of the substrate; an orthographic projection of the fourth recessed region on the substrate is located within an orthographic projection of the second groove on the substrate; Wherein, the refractive index of the dielectric material layer is different from the refractive index of the first non-light-transmissive film layer.

9. The photolithography alignment method according to any one of claims 1 to 8, characterized in that: The material of the metal layer is Cu material or Al material.

10. The photolithography alignment method according to any one of claims 1 to 8, characterized in that: The material of the first non-light-transmitting film layer is Ag material or Al material; The material of the second non-light-transmitting film layer is Ag material or Al material.

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